xref: /xnu-11417.140.69/bsd/kern/kern_exec.c (revision 43a90889846e00bfb5cf1d255cdc0a701a1e05a4)
1 /*
2  * Copyright (c) 2000-2020 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
29 /*
30  * Mach Operating System
31  * Copyright (c) 1987 Carnegie-Mellon University
32  * All rights reserved.  The CMU software License Agreement specifies
33  * the terms and conditions for use and redistribution.
34  */
35 
36 /*-
37  * Copyright (c) 1982, 1986, 1991, 1993
38  *	The Regents of the University of California.  All rights reserved.
39  * (c) UNIX System Laboratories, Inc.
40  * All or some portions of this file are derived from material licensed
41  * to the University of California by American Telephone and Telegraph
42  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
43  * the permission of UNIX System Laboratories, Inc.
44  *
45  * Redistribution and use in source and binary forms, with or without
46  * modification, are permitted provided that the following conditions
47  * are met:
48  * 1. Redistributions of source code must retain the above copyright
49  *    notice, this list of conditions and the following disclaimer.
50  * 2. Redistributions in binary form must reproduce the above copyright
51  *    notice, this list of conditions and the following disclaimer in the
52  *    documentation and/or other materials provided with the distribution.
53  * 3. All advertising materials mentioning features or use of this software
54  *    must display the following acknowledgement:
55  *	This product includes software developed by the University of
56  *	California, Berkeley and its contributors.
57  * 4. Neither the name of the University nor the names of its contributors
58  *    may be used to endorse or promote products derived from this software
59  *    without specific prior written permission.
60  *
61  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
62  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
63  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
64  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
65  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
66  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
67  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
68  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
69  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
70  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
71  * SUCH DAMAGE.
72  *
73  *	from: @(#)kern_exec.c	8.1 (Berkeley) 6/10/93
74  */
75 /*
76  * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
77  * support for mandatory and extensible security protections.  This notice
78  * is included in support of clause 2.2 (b) of the Apple Public License,
79  * Version 2.0.
80  */
81 #include <machine/reg.h>
82 #include <machine/cpu_capabilities.h>
83 
84 #include <sys/cdefs.h>
85 #include <sys/param.h>
86 #include <sys/systm.h>
87 #include <sys/filedesc.h>
88 #include <sys/kernel.h>
89 #include <sys/proc_internal.h>
90 #include <sys/kauth.h>
91 #include <sys/user.h>
92 #include <sys/socketvar.h>
93 #include <sys/malloc.h>
94 #include <sys/namei.h>
95 #include <sys/mount_internal.h>
96 #include <sys/vnode_internal.h>
97 #include <sys/file_internal.h>
98 #include <sys/stat.h>
99 #include <sys/uio_internal.h>
100 #include <sys/acct.h>
101 #include <sys/exec.h>
102 #include <sys/kdebug.h>
103 #include <sys/signal.h>
104 #include <sys/aio_kern.h>
105 #include <sys/sysproto.h>
106 #include <sys/sysctl.h>
107 #include <sys/persona.h>
108 #include <sys/reason.h>
109 #if SYSV_SHM
110 #include <sys/shm_internal.h>           /* shmexec() */
111 #endif
112 #include <sys/ubc_internal.h>           /* ubc_map() */
113 #include <sys/spawn.h>
114 #include <sys/spawn_internal.h>
115 #include <sys/process_policy.h>
116 #include <sys/codesign.h>
117 #include <sys/random.h>
118 #include <crypto/sha1.h>
119 
120 #include <libkern/libkern.h>
121 #include <libkern/amfi/amfi.h>
122 #include <libkern/crypto/sha2.h>
123 #include <security/audit/audit.h>
124 
125 #include <ipc/ipc_types.h>
126 
127 #include <mach/mach_param.h>
128 #include <mach/mach_types.h>
129 #include <mach/port.h>
130 #include <mach/task.h>
131 #include <mach/task_access.h>
132 #include <mach/thread_act.h>
133 #include <mach/vm_map.h>
134 #include <mach/mach_vm.h>
135 #include <mach/vm_param.h>
136 #include <mach_debug/mach_debug_types.h>
137 
138 #include <kern/sched_prim.h> /* thread_wakeup() */
139 #include <kern/affinity.h>
140 #include <kern/assert.h>
141 #include <kern/ipc_kobject.h>
142 #include <kern/task.h>
143 #include <kern/thread.h>
144 #include <kern/coalition.h>
145 #include <kern/policy_internal.h>
146 #include <kern/kalloc.h>
147 #include <kern/zalloc.h> /* zone_userspace_reboot_checks() */
148 
149 #include <os/log.h>
150 
151 #if CONFIG_MACF
152 #include <security/mac_framework.h>
153 #include <security/mac_mach_internal.h>
154 #endif
155 
156 #if CONFIG_AUDIT
157 #include <bsm/audit_kevents.h>
158 #endif
159 
160 #if CONFIG_ARCADE
161 #include <kern/arcade.h>
162 #endif
163 
164 #include <vm/vm_map_xnu.h>
165 #include <vm/vm_kern_xnu.h>
166 #include <vm/vm_protos.h>
167 #include <vm/vm_fault.h>
168 #include <vm/vm_pageout_xnu.h>
169 #include <vm/pmap.h>
170 #include <vm/vm_reclaim_xnu.h>
171 
172 #include <kdp/kdp_dyld.h>
173 
174 #include <machine/machine_routines.h>
175 #include <machine/pal_routines.h>
176 
177 #include <pexpert/pexpert.h>
178 #include <pexpert/device_tree.h>
179 
180 #if CONFIG_MEMORYSTATUS
181 #include <sys/kern_memorystatus.h>
182 #endif
183 
184 #include <IOKit/IOBSD.h>
185 #include <IOKit/IOKitKeys.h> /* kIODriverKitEntitlementKey */
186 
187 #include "kern_exec_internal.h"
188 
189 #include <CodeSignature/Entitlements.h>
190 
191 #include <mach/exclaves.h>
192 
193 
194 extern boolean_t vm_darkwake_mode;
195 
196 /* enable crash reports on various exec failures */
197 static TUNABLE(bool, bootarg_execfailurereports, "execfailurecrashes", false);
198 
199 #if XNU_TARGET_OS_OSX
200 #if __has_feature(ptrauth_calls)
201 static TUNABLE(bool, bootarg_arm64e_preview_abi, "-arm64e_preview_abi", false);
202 #endif /* __has_feature(ptrauth_calls) */
203 
204 #if DEBUG || DEVELOPMENT
205 static TUNABLE(bool, unentitled_ios_sim_launch, "unentitled_ios_sim_launch", false);
206 #endif /* DEBUG || DEVELOPMENT */
207 #endif /* XNU_TARGET_OS_OSX */
208 
209 #if DEVELOPMENT || DEBUG
210 os_log_t exec_log_handle = NULL;
211 #define EXEC_LOG(fmt, ...)      \
212 do {    \
213 	if (exec_log_handle) {      \
214 	        os_log_with_type(exec_log_handle, OS_LOG_TYPE_INFO, "exec - %s:%d " fmt, __FUNCTION__, __LINE__, ##__VA_ARGS__);    \
215 	}   \
216 } while (0)
217 #else /* DEVELOPMENT || DEBUG */
218 #define EXEC_LOG(fmt, ...)  do { } while (0)
219 #endif /* DEVELOPMENT || DEBUG */
220 
221 #if CONFIG_DTRACE
222 /* Do not include dtrace.h, it redefines kmem_[alloc/free] */
223 extern void dtrace_proc_exec(proc_t);
224 extern void (*dtrace_proc_waitfor_exec_ptr)(proc_t);
225 
226 /*
227  * Since dtrace_proc_waitfor_exec_ptr can be added/removed in dtrace_subr.c,
228  * we will store its value before actually calling it.
229  */
230 static void (*dtrace_proc_waitfor_hook)(proc_t) = NULL;
231 
232 #include <sys/dtrace_ptss.h>
233 #endif
234 
235 #if __has_feature(ptrauth_calls)
236 static TUNABLE_DEV_WRITEABLE(int, vm_shared_region_per_team_id,
237     "vm_shared_region_per_team_id", 1);
238 static TUNABLE_DEV_WRITEABLE(int, vm_shared_region_by_entitlement,
239     "vm_shared_region_by_entitlement", 1);
240 
241 /* Upon userland request, reslide the shared cache. */
242 static TUNABLE_DEV_WRITEABLE(int, vm_shared_region_reslide_aslr,
243     "vm_shared_region_reslide_aslr",
244 #if CONFIG_RESLIDE_SHARED_CACHE
245     1
246 #else
247     0
248 #endif /* CONFIG_RESLIDE_SHARED_CACHE */
249     );
250 
251 /*
252  * Flag to control what processes should get shared cache randomize resliding
253  * after a fault in the shared cache region:
254  *
255  * 0 - all processes get a new randomized slide
256  * 1 - only platform processes get a new randomized slide
257  */
258 TUNABLE_DEV_WRITEABLE(int, vm_shared_region_reslide_restrict,
259     "vm_shared_region_reslide_restrict", 1);
260 
261 #if DEVELOPMENT || DEBUG
262 SYSCTL_INT(_vm, OID_AUTO, vm_shared_region_per_team_id,
263     CTLFLAG_RW, &vm_shared_region_per_team_id, 0, "");
264 SYSCTL_INT(_vm, OID_AUTO, vm_shared_region_by_entitlement,
265     CTLFLAG_RW, &vm_shared_region_by_entitlement, 0, "");
266 SYSCTL_INT(_vm, OID_AUTO, vm_shared_region_reslide_restrict,
267     CTLFLAG_RW, &vm_shared_region_reslide_restrict, 0, "");
268 SYSCTL_INT(_vm, OID_AUTO, vm_shared_region_reslide_aslr,
269     CTLFLAG_RW, &vm_shared_region_reslide_aslr, 0, "");
270 #endif
271 #endif /* __has_feature(ptrauth_calls) */
272 
273 #if DEVELOPMENT || DEBUG
274 static TUNABLE(bool, enable_dext_coredumps_on_panic, "dext_panic_coredump", true);
275 #else
276 static TUNABLE(bool, enable_dext_coredumps_on_panic, "dext_panic_coredump", false);
277 #endif
278 extern kern_return_t kern_register_userspace_coredump(task_t task, const char * name);
279 #define USERSPACE_COREDUMP_PANIC_ENTITLEMENT "com.apple.private.enable-coredump-on-panic"
280 #define USERSPACE_COREDUMP_PANIC_SEED_ENTITLEMENT \
281 	"com.apple.private.enable-coredump-on-panic-seed-privacy-approved"
282 
283 extern void proc_apply_task_networkbg_internal(proc_t, thread_t);
284 extern void task_set_did_exec_flag(task_t task);
285 extern void task_clear_exec_copy_flag(task_t task);
286 proc_t proc_exec_switch_task(proc_t old_proc, proc_t new_proc, task_t old_task,
287     task_t new_task, struct image_params *imgp, void **inherit);
288 boolean_t task_is_active(task_t);
289 boolean_t thread_is_active(thread_t thread);
290 void thread_copy_resource_info(thread_t dst_thread, thread_t src_thread);
291 void *ipc_importance_exec_switch_task(task_t old_task, task_t new_task);
292 extern void ipc_importance_release(void *elem);
293 extern boolean_t task_has_watchports(task_t task);
294 extern void task_set_no_smt(task_t task);
295 #if defined(HAS_APPLE_PAC)
296 char *task_get_vm_shared_region_id_and_jop_pid(task_t task, uint64_t *jop_pid);
297 #endif
298 task_t convert_port_to_task(ipc_port_t port);
299 
300 #if CONFIG_EXCLAVES
301 int task_add_conclave(task_t task, void *vnode, int64_t off, const char *task_conclave_id);
302 kern_return_t task_inherit_conclave(task_t old_task, task_t new_task, void *vnode, int64_t off);
303 #endif /* CONFIG_EXCLAVES */
304 
305 /*
306  * Mach things for which prototypes are unavailable from Mach headers
307  */
308 extern void ipc_task_enable(task_t task);
309 extern void ipc_task_reset(task_t task);
310 extern void ipc_thread_reset(thread_t thread);
311 
312 #if DEVELOPMENT || DEBUG
313 void task_importance_update_owner_info(task_t);
314 #endif
315 
316 extern struct savearea *get_user_regs(thread_t);
317 
318 __attribute__((noinline)) int __EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__(mach_port_t task_access_port, int32_t new_pid);
319 
320 #include <kern/thread.h>
321 #include <kern/task.h>
322 #include <kern/ast.h>
323 #include <kern/mach_loader.h>
324 #include <kern/mach_fat.h>
325 #include <mach-o/fat.h>
326 #include <mach-o/loader.h>
327 #include <machine/vmparam.h>
328 #include <sys/imgact.h>
329 
330 #include <sys/sdt.h>
331 
332 
333 /*
334  * EAI_ITERLIMIT	The maximum number of times to iterate an image
335  *			activator in exec_activate_image() before treating
336  *			it as malformed/corrupt.
337  */
338 #define EAI_ITERLIMIT           3
339 
340 /*
341  * For #! interpreter parsing
342  */
343 #define IS_WHITESPACE(ch) ((ch == ' ') || (ch == '\t'))
344 #define IS_EOL(ch) ((ch == '#') || (ch == '\n'))
345 
346 extern vm_map_t bsd_pageable_map;
347 extern const struct fileops vnops;
348 extern int nextpidversion;
349 
350 
351 #define USER_ADDR_ALIGN(addr, val) \
352 	( ( (user_addr_t)(addr) + (val) - 1) \
353 	        & ~((val) - 1) )
354 
355 /*
356  * For subsystem root support
357  */
358 #define SPAWN_SUBSYSTEM_ROOT_ENTITLEMENT "com.apple.private.spawn-subsystem-root"
359 
360 /*
361  * Allow setting p_crash_behavior to trigger panic on crash
362  */
363 #define SPAWN_SET_PANIC_CRASH_BEHAVIOR "com.apple.private.spawn-panic-crash-behavior"
364 
365 /* Platform Code Exec Logging */
366 static int platform_exec_logging = 0;
367 
368 SYSCTL_DECL(_security_mac);
369 
370 SYSCTL_INT(_security_mac, OID_AUTO, platform_exec_logging, CTLFLAG_RW, &platform_exec_logging, 0,
371     "log cdhashes for all platform binary executions");
372 
373 static os_log_t peLog = OS_LOG_DEFAULT;
374 
375 struct exception_port_action_t {
376 	ipc_port_t port;
377 	_ps_port_action_t *port_action;
378 };
379 
380 struct exec_port_actions {
381 	uint32_t exception_port_count;
382 	uint32_t portwatch_count;
383 	uint32_t registered_count;
384 	struct exception_port_action_t *excport_array;
385 	ipc_port_t *portwatch_array;
386 	ipc_port_t registered_array[TASK_PORT_REGISTER_MAX];
387 };
388 
389 struct image_params;    /* Forward */
390 static int exec_activate_image(struct image_params *imgp);
391 static int exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp);
392 static int load_return_to_errno(load_return_t lrtn);
393 static int execargs_alloc(struct image_params *imgp);
394 static int execargs_free(struct image_params *imgp);
395 static int exec_check_permissions(struct image_params *imgp);
396 static int exec_extract_strings(struct image_params *imgp);
397 static int exec_add_apple_strings(struct image_params *imgp, const load_result_t *load_result, task_t task);
398 static int exec_handle_sugid(struct image_params *imgp);
399 static int sugid_scripts = 0;
400 SYSCTL_INT(_kern, OID_AUTO, sugid_scripts, CTLFLAG_RW | CTLFLAG_LOCKED, &sugid_scripts, 0, "");
401 static kern_return_t create_unix_stack(vm_map_t map, load_result_t* load_result, proc_t p);
402 static int copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size);
403 static void exec_resettextvp(proc_t, struct image_params *);
404 static int process_signature(proc_t, struct image_params *);
405 static void exec_prefault_data(proc_t, struct image_params *, load_result_t *);
406 static errno_t exec_handle_port_actions(struct image_params *imgp,
407     struct exec_port_actions *port_actions);
408 static errno_t exec_handle_exception_port_actions(const struct image_params *imgp,
409     const struct exec_port_actions *port_actions);
410 static errno_t exec_handle_spawnattr_policy(proc_t p, thread_t thread, int psa_apptype, uint64_t psa_qos_clamp,
411     task_role_t psa_darwin_role, struct exec_port_actions *port_actions);
412 static void exec_port_actions_destroy(struct exec_port_actions *port_actions);
413 
414 /*
415  * exec_add_user_string
416  *
417  * Add the requested string to the string space area.
418  *
419  * Parameters;	struct image_params *		image parameter block
420  *		user_addr_t			string to add to strings area
421  *		int				segment from which string comes
422  *		boolean_t			TRUE if string contributes to NCARGS
423  *
424  * Returns:	0			Success
425  *		!0			Failure errno from copyinstr()
426  *
427  * Implicit returns:
428  *		(imgp->ip_strendp)	updated location of next add, if any
429  *		(imgp->ip_strspace)	updated byte count of space remaining
430  *		(imgp->ip_argspace) updated byte count of space in NCARGS
431  */
432 __attribute__((noinline))
433 static int
exec_add_user_string(struct image_params * imgp,user_addr_t str,int seg,boolean_t is_ncargs)434 exec_add_user_string(struct image_params *imgp, user_addr_t str, int seg, boolean_t is_ncargs)
435 {
436 	int error = 0;
437 
438 	do {
439 		size_t len = 0;
440 		int space;
441 
442 		if (is_ncargs) {
443 			space = imgp->ip_argspace; /* by definition smaller than ip_strspace */
444 		} else {
445 			space = imgp->ip_strspace;
446 		}
447 
448 		if (space <= 0) {
449 			error = E2BIG;
450 			break;
451 		}
452 
453 		if (!UIO_SEG_IS_USER_SPACE(seg)) {
454 			char *kstr = CAST_DOWN(char *, str);     /* SAFE */
455 			error = copystr(kstr, imgp->ip_strendp, space, &len);
456 		} else {
457 			error = copyinstr(str, imgp->ip_strendp, space, &len);
458 		}
459 
460 		imgp->ip_strendp += len;
461 		imgp->ip_strspace -= len;
462 		if (is_ncargs) {
463 			imgp->ip_argspace -= len;
464 		}
465 	} while (error == ENAMETOOLONG);
466 
467 	return error;
468 }
469 
470 /*
471  * dyld is now passed the executable path as a getenv-like variable
472  * in the same fashion as the stack_guard and malloc_entropy keys.
473  */
474 #define EXECUTABLE_KEY "executable_path="
475 
476 /*
477  * exec_save_path
478  *
479  * To support new app package launching for Mac OS X, the dyld needs the
480  * first argument to execve() stored on the user stack.
481  *
482  * Save the executable path name at the bottom of the strings area and set
483  * the argument vector pointer to the location following that to indicate
484  * the start of the argument and environment tuples, setting the remaining
485  * string space count to the size of the string area minus the path length.
486  *
487  * Parameters;	struct image_params *		image parameter block
488  *		char *				path used to invoke program
489  *		int				segment from which path comes
490  *
491  * Returns:	int			0	Success
492  *		EFAULT				Bad address
493  *	copy[in]str:EFAULT			Bad address
494  *	copy[in]str:ENAMETOOLONG		Filename too long
495  *
496  * Implicit returns:
497  *		(imgp->ip_strings)		saved path
498  *		(imgp->ip_strspace)		space remaining in ip_strings
499  *		(imgp->ip_strendp)		start of remaining copy area
500  *		(imgp->ip_argspace)		space remaining of NCARGS
501  *		(imgp->ip_applec)		Initial applev[0]
502  *
503  * Note:	We have to do this before the initial namei() since in the
504  *		path contains symbolic links, namei() will overwrite the
505  *		original path buffer contents.  If the last symbolic link
506  *		resolved was a relative pathname, we would lose the original
507  *		"path", which could be an absolute pathname. This might be
508  *		unacceptable for dyld.
509  */
510 static int
exec_save_path(struct image_params * imgp,user_addr_t path,int seg,const char ** excpath)511 exec_save_path(struct image_params *imgp, user_addr_t path, int seg, const char **excpath)
512 {
513 	int error;
514 	size_t len;
515 	char *kpath;
516 
517 	// imgp->ip_strings can come out of a cache, so we need to obliterate the
518 	// old path.
519 	memset(imgp->ip_strings, '\0', strlen(EXECUTABLE_KEY) + MAXPATHLEN);
520 
521 	len = MIN(MAXPATHLEN, imgp->ip_strspace);
522 
523 	switch (seg) {
524 	case UIO_USERSPACE32:
525 	case UIO_USERSPACE64:   /* Same for copyin()... */
526 		error = copyinstr(path, imgp->ip_strings + strlen(EXECUTABLE_KEY), len, &len);
527 		break;
528 	case UIO_SYSSPACE:
529 		kpath = CAST_DOWN(char *, path); /* SAFE */
530 		error = copystr(kpath, imgp->ip_strings + strlen(EXECUTABLE_KEY), len, &len);
531 		break;
532 	default:
533 		error = EFAULT;
534 		break;
535 	}
536 
537 	if (!error) {
538 		bcopy(EXECUTABLE_KEY, imgp->ip_strings, strlen(EXECUTABLE_KEY));
539 		len += strlen(EXECUTABLE_KEY);
540 
541 		imgp->ip_strendp += len;
542 		imgp->ip_strspace -= len;
543 
544 		if (excpath) {
545 			*excpath = imgp->ip_strings + strlen(EXECUTABLE_KEY);
546 		}
547 	}
548 
549 	return error;
550 }
551 
552 /*
553  * exec_reset_save_path
554  *
555  * If we detect a shell script, we need to reset the string area
556  * state so that the interpreter can be saved onto the stack.
557  *
558  * Parameters;	struct image_params *		image parameter block
559  *
560  * Returns:	int			0	Success
561  *
562  * Implicit returns:
563  *		(imgp->ip_strings)		saved path
564  *		(imgp->ip_strspace)		space remaining in ip_strings
565  *		(imgp->ip_strendp)		start of remaining copy area
566  *		(imgp->ip_argspace)		space remaining of NCARGS
567  *
568  */
569 static int
exec_reset_save_path(struct image_params * imgp)570 exec_reset_save_path(struct image_params *imgp)
571 {
572 	imgp->ip_strendp = imgp->ip_strings;
573 	imgp->ip_argspace = NCARGS;
574 	imgp->ip_strspace = (NCARGS + PAGE_SIZE);
575 
576 	return 0;
577 }
578 
579 /*
580  * exec_shell_imgact
581  *
582  * Image activator for interpreter scripts.  If the image begins with
583  * the characters "#!", then it is an interpreter script.  Verify the
584  * length of the script line indicating the interpreter is not in
585  * excess of the maximum allowed size.  If this is the case, then
586  * break out the arguments, if any, which are separated by white
587  * space, and copy them into the argument save area as if they were
588  * provided on the command line before all other arguments.  The line
589  * ends when we encounter a comment character ('#') or newline.
590  *
591  * Parameters;	struct image_params *	image parameter block
592  *
593  * Returns:	-1			not an interpreter (keep looking)
594  *		-3			Success: interpreter: relookup
595  *		>0			Failure: interpreter: error number
596  *
597  * A return value other than -1 indicates subsequent image activators should
598  * not be given the opportunity to attempt to activate the image.
599  */
600 static int
exec_shell_imgact(struct image_params * imgp)601 exec_shell_imgact(struct image_params *imgp)
602 {
603 	char *vdata = imgp->ip_vdata;
604 	char *ihp;
605 	char *line_startp, *line_endp;
606 	char *interp;
607 
608 	/*
609 	 * Make sure it's a shell script.  If we've already redirected
610 	 * from an interpreted file once, don't do it again.
611 	 */
612 	if (vdata[0] != '#' ||
613 	    vdata[1] != '!' ||
614 	    (imgp->ip_flags & IMGPF_INTERPRET) != 0) {
615 		return -1;
616 	}
617 
618 	if (imgp->ip_origcputype != 0) {
619 		/* Fat header previously matched, don't allow shell script inside */
620 		return -1;
621 	}
622 
623 	imgp->ip_flags |= IMGPF_INTERPRET;
624 	imgp->ip_interp_sugid_fd = -1;
625 	imgp->ip_interp_buffer[0] = '\0';
626 
627 	/* Check to see if SUGID scripts are permitted.  If they aren't then
628 	 * clear the SUGID bits.
629 	 * imgp->ip_vattr is known to be valid.
630 	 */
631 	if (sugid_scripts == 0) {
632 		imgp->ip_origvattr->va_mode &= ~(VSUID | VSGID);
633 	}
634 
635 	/* Try to find the first non-whitespace character */
636 	for (ihp = &vdata[2]; ihp < &vdata[IMG_SHSIZE]; ihp++) {
637 		if (IS_EOL(*ihp)) {
638 			/* Did not find interpreter, "#!\n" */
639 			return ENOEXEC;
640 		} else if (IS_WHITESPACE(*ihp)) {
641 			/* Whitespace, like "#!    /bin/sh\n", keep going. */
642 		} else {
643 			/* Found start of interpreter */
644 			break;
645 		}
646 	}
647 
648 	if (ihp == &vdata[IMG_SHSIZE]) {
649 		/* All whitespace, like "#!           " */
650 		return ENOEXEC;
651 	}
652 
653 	line_startp = ihp;
654 
655 	/* Try to find the end of the interpreter+args string */
656 	for (; ihp < &vdata[IMG_SHSIZE]; ihp++) {
657 		if (IS_EOL(*ihp)) {
658 			/* Got it */
659 			break;
660 		} else {
661 			/* Still part of interpreter or args */
662 		}
663 	}
664 
665 	if (ihp == &vdata[IMG_SHSIZE]) {
666 		/* A long line, like "#! blah blah blah" without end */
667 		return ENOEXEC;
668 	}
669 
670 	/* Backtrack until we find the last non-whitespace */
671 	while (IS_EOL(*ihp) || IS_WHITESPACE(*ihp)) {
672 		ihp--;
673 	}
674 
675 	/* The character after the last non-whitespace is our logical end of line */
676 	line_endp = ihp + 1;
677 
678 	/*
679 	 * Now we have pointers to the usable part of:
680 	 *
681 	 * "#!  /usr/bin/int first    second   third    \n"
682 	 *      ^ line_startp                       ^ line_endp
683 	 */
684 
685 	/* copy the interpreter name */
686 	interp = imgp->ip_interp_buffer;
687 	for (ihp = line_startp; (ihp < line_endp) && !IS_WHITESPACE(*ihp); ihp++) {
688 		*interp++ = *ihp;
689 	}
690 	*interp = '\0';
691 
692 	exec_reset_save_path(imgp);
693 	exec_save_path(imgp, CAST_USER_ADDR_T(imgp->ip_interp_buffer),
694 	    UIO_SYSSPACE, NULL);
695 
696 	/* Copy the entire interpreter + args for later processing into argv[] */
697 	interp = imgp->ip_interp_buffer;
698 	for (ihp = line_startp; (ihp < line_endp); ihp++) {
699 		*interp++ = *ihp;
700 	}
701 	*interp = '\0';
702 
703 #if CONFIG_SETUID
704 	/*
705 	 * If we have an SUID or SGID script, create a file descriptor
706 	 * from the vnode and pass /dev/fd/%d instead of the actual
707 	 * path name so that the script does not get opened twice
708 	 */
709 	if (imgp->ip_origvattr->va_mode & (VSUID | VSGID)) {
710 		proc_t p;
711 		struct fileproc *fp;
712 		int fd;
713 		int error;
714 
715 		p = vfs_context_proc(imgp->ip_vfs_context);
716 		error = falloc_exec(p, imgp->ip_vfs_context, &fp, &fd);
717 		if (error) {
718 			return error;
719 		}
720 
721 		fp->fp_glob->fg_flag = FREAD;
722 		fp->fp_glob->fg_ops = &vnops;
723 		fp_set_data(fp, imgp->ip_vp);
724 
725 		proc_fdlock(p);
726 		procfdtbl_releasefd(p, fd, NULL);
727 		fp_drop(p, fd, fp, 1);
728 		proc_fdunlock(p);
729 		vnode_ref(imgp->ip_vp);
730 
731 		imgp->ip_interp_sugid_fd = fd;
732 	}
733 #endif /* CONFIG_SETUID */
734 
735 	return -3;
736 }
737 
738 
739 
740 /*
741  * exec_fat_imgact
742  *
743  * Image activator for fat 1.0 binaries.  If the binary is fat, then we
744  * need to select an image from it internally, and make that the image
745  * we are going to attempt to execute.  At present, this consists of
746  * reloading the first page for the image with a first page from the
747  * offset location indicated by the fat header.
748  *
749  * Parameters;	struct image_params *	image parameter block
750  *
751  * Returns:	-1			not a fat binary (keep looking)
752  *		-2			Success: encapsulated binary: reread
753  *		>0			Failure: error number
754  *
755  * Important:	This image activator is byte order neutral.
756  *
757  * Note:	A return value other than -1 indicates subsequent image
758  *		activators should not be given the opportunity to attempt
759  *		to activate the image.
760  *
761  *              If we find an encapsulated binary, we make no assertions
762  *		about its  validity; instead, we leave that up to a rescan
763  *		for an activator to claim it, and, if it is claimed by one,
764  *		that activator is responsible for determining validity.
765  */
766 static int
exec_fat_imgact(struct image_params * imgp)767 exec_fat_imgact(struct image_params *imgp)
768 {
769 	proc_t p = vfs_context_proc(imgp->ip_vfs_context);
770 	kauth_cred_t cred = kauth_cred_proc_ref(p);
771 	struct fat_header *fat_header = (struct fat_header *)imgp->ip_vdata;
772 	struct _posix_spawnattr *psa = NULL;
773 	struct fat_arch fat_arch;
774 	int resid, error;
775 	load_return_t lret;
776 
777 	if (imgp->ip_origcputype != 0) {
778 		/* Fat header previously matched, don't allow another fat file inside */
779 		error = -1; /* not claimed */
780 		goto bad;
781 	}
782 
783 	/* Make sure it's a fat binary */
784 	if (OSSwapBigToHostInt32(fat_header->magic) != FAT_MAGIC) {
785 		error = -1; /* not claimed */
786 		goto bad;
787 	}
788 
789 	/* imgp->ip_vdata has PAGE_SIZE, zerofilled if the file is smaller */
790 	lret = fatfile_validate_fatarches((vm_offset_t)fat_header, PAGE_SIZE,
791 	    (off_t)imgp->ip_vattr->va_data_size);
792 	if (lret != LOAD_SUCCESS) {
793 		error = load_return_to_errno(lret);
794 		goto bad;
795 	}
796 
797 	/* If posix_spawn binprefs exist, respect those prefs. */
798 	psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
799 	if (psa != NULL && psa->psa_binprefs[0] != 0) {
800 		uint32_t pr = 0;
801 
802 		/* Check each preference listed against all arches in header */
803 		for (pr = 0; pr < NBINPREFS; pr++) {
804 			cpu_type_t pref = psa->psa_binprefs[pr];
805 			cpu_type_t subpref = psa->psa_subcpuprefs[pr];
806 
807 			if (pref == 0) {
808 				/* No suitable arch in the pref list */
809 				error = EBADARCH;
810 				goto bad;
811 			}
812 
813 			if (pref == CPU_TYPE_ANY) {
814 				/* Fall through to regular grading */
815 				goto regular_grading;
816 			}
817 
818 			lret = fatfile_getbestarch_for_cputype(pref,
819 			    subpref,
820 			    (vm_offset_t)fat_header,
821 			    PAGE_SIZE,
822 			    imgp,
823 			    &fat_arch);
824 			if (lret == LOAD_SUCCESS) {
825 				goto use_arch;
826 			}
827 		}
828 
829 		/* Requested binary preference was not honored */
830 		error = EBADEXEC;
831 		goto bad;
832 	}
833 
834 regular_grading:
835 	/* Look up our preferred architecture in the fat file. */
836 	lret = fatfile_getbestarch((vm_offset_t)fat_header,
837 	    PAGE_SIZE,
838 	    imgp,
839 	    &fat_arch,
840 	    (p->p_flag & P_AFFINITY) != 0);
841 	if (lret != LOAD_SUCCESS) {
842 		error = load_return_to_errno(lret);
843 		goto bad;
844 	}
845 
846 use_arch:
847 	/* Read the Mach-O header out of fat_arch */
848 	error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata,
849 	    PAGE_SIZE, fat_arch.offset,
850 	    UIO_SYSSPACE, (IO_UNIT | IO_NODELOCKED),
851 	    cred, &resid, p);
852 	if (error) {
853 		if (error == ERESTART) {
854 			error = EINTR;
855 		}
856 		goto bad;
857 	}
858 
859 	if (resid) {
860 		memset(imgp->ip_vdata + (PAGE_SIZE - resid), 0x0, resid);
861 	}
862 
863 	/* Success.  Indicate we have identified an encapsulated binary */
864 	error = -2;
865 	imgp->ip_arch_offset = (user_size_t)fat_arch.offset;
866 	imgp->ip_arch_size = (user_size_t)fat_arch.size;
867 	imgp->ip_origcputype = fat_arch.cputype;
868 	imgp->ip_origcpusubtype = fat_arch.cpusubtype;
869 
870 bad:
871 	kauth_cred_unref(&cred);
872 	return error;
873 }
874 
875 static int
activate_exec_state(task_t task,proc_t p,thread_t thread,load_result_t * result)876 activate_exec_state(task_t task, proc_t p, thread_t thread, load_result_t *result)
877 {
878 	int ret;
879 
880 	(void)task_set_dyld_info(task, MACH_VM_MIN_ADDRESS, 0, false);
881 	task_set_64bit(task, result->is_64bit_addr, result->is_64bit_data);
882 	if (result->is_64bit_addr) {
883 		OSBitOrAtomic(P_LP64, &p->p_flag);
884 		get_bsdthread_info(thread)->uu_flag |= UT_LP64;
885 	} else {
886 		OSBitAndAtomic(~((uint32_t)P_LP64), &p->p_flag);
887 		get_bsdthread_info(thread)->uu_flag &= ~UT_LP64;
888 	}
889 	task_set_mach_header_address(task, result->mach_header);
890 
891 	ret = thread_state_initialize(thread);
892 	if (ret != KERN_SUCCESS) {
893 		return ret;
894 	}
895 
896 	if (result->threadstate) {
897 		uint32_t *ts = result->threadstate;
898 		uint32_t total_size = (uint32_t)result->threadstate_sz;
899 
900 		while (total_size > 0) {
901 			uint32_t flavor = *ts++;
902 			uint32_t size = *ts++;
903 
904 			ret = thread_setstatus(thread, flavor, (thread_state_t)ts, size);
905 			if (ret) {
906 				return ret;
907 			}
908 			ts += size;
909 			total_size -= (size + 2) * sizeof(uint32_t);
910 		}
911 	}
912 
913 	thread_setentrypoint(thread, result->entry_point);
914 
915 	return KERN_SUCCESS;
916 }
917 
918 #if (DEVELOPMENT || DEBUG)
919 extern char panic_on_proc_crash[];
920 extern int use_panic_on_proc_crash;
921 
922 extern char panic_on_proc_exit[];
923 extern int use_panic_on_proc_exit;
924 
925 extern char panic_on_proc_spawn_fail[];
926 extern int use_panic_on_proc_spawn_fail;
927 
928 static inline void
set_crash_behavior_from_bootarg(proc_t p)929 set_crash_behavior_from_bootarg(proc_t p)
930 {
931 	if (use_panic_on_proc_crash && strcmp(p->p_comm, panic_on_proc_crash) == 0) {
932 		printf("will panic on proc crash: %s\n", p->p_comm);
933 		p->p_crash_behavior |= POSIX_SPAWN_PANIC_ON_CRASH;
934 	}
935 
936 	if (use_panic_on_proc_exit && strcmp(p->p_comm, panic_on_proc_exit) == 0) {
937 		printf("will panic on proc exit: %s\n", p->p_comm);
938 		p->p_crash_behavior |= POSIX_SPAWN_PANIC_ON_EXIT;
939 	}
940 
941 	if (use_panic_on_proc_spawn_fail && strcmp(p->p_comm, panic_on_proc_spawn_fail) == 0) {
942 		printf("will panic on proc spawn fail: %s\n", p->p_comm);
943 		p->p_crash_behavior |= POSIX_SPAWN_PANIC_ON_SPAWN_FAIL;
944 	}
945 }
946 #endif
947 
948 void
set_proc_name(struct image_params * imgp,proc_t p)949 set_proc_name(struct image_params *imgp, proc_t p)
950 {
951 	uint64_t buflen = imgp->ip_ndp->ni_cnd.cn_namelen;
952 	const int p_name_len = sizeof(p->p_name) - 1;
953 	const int p_comm_len = sizeof(p->p_comm) - 1;
954 
955 	if (buflen > p_name_len) {
956 		buflen = p_name_len;
957 	}
958 
959 	bcopy((caddr_t)imgp->ip_ndp->ni_cnd.cn_nameptr, (caddr_t)p->p_name, buflen);
960 	p->p_name[buflen] = '\0';
961 
962 	if (buflen > p_comm_len) {
963 		static_assert(MAXCOMLEN + 1 == sizeof(p->p_comm));
964 		buflen = p_comm_len;
965 	}
966 
967 	bcopy((caddr_t)imgp->ip_ndp->ni_cnd.cn_nameptr, (caddr_t)p->p_comm, buflen);
968 	p->p_comm[buflen] = '\0';
969 
970 #if (DEVELOPMENT || DEBUG)
971 	/*
972 	 * This happens during image activation, so the crash behavior flags from
973 	 * posix_spawn will have already been set. So we don't have to worry about
974 	 * this being overridden.
975 	 */
976 	set_crash_behavior_from_bootarg(p);
977 #endif
978 }
979 
980 #if __has_feature(ptrauth_calls)
981 /**
982  * Returns a team ID string that may be used to assign a shared region.
983  *
984  * Platform binaries do not have team IDs and will return NULL.  Non-platform
985  * binaries without a team ID will be assigned an artificial team ID of ""
986  * (empty string) so that they will not be assigned to the default shared
987  * region.
988  *
989  * @param imgp image parameter block
990  * @return NULL if this is a platform binary, or an appropriate team ID string
991  *         otherwise
992  */
993 static inline const char *
get_teamid_for_shared_region(struct image_params * imgp)994 get_teamid_for_shared_region(struct image_params *imgp)
995 {
996 	assert(imgp->ip_vp != NULL);
997 
998 	const char *ret = csvnode_get_teamid(imgp->ip_vp, imgp->ip_arch_offset);
999 	if (ret) {
1000 		return ret;
1001 	}
1002 
1003 	struct cs_blob *blob = csvnode_get_blob(imgp->ip_vp, imgp->ip_arch_offset);
1004 	if (csblob_get_platform_binary(blob)) {
1005 		return NULL;
1006 	} else {
1007 		static const char *NO_TEAM_ID = "";
1008 		return NO_TEAM_ID;
1009 	}
1010 }
1011 
1012 /**
1013  * Determines whether ptrauth should be enabled for the provided arm64 CPU subtype.
1014  *
1015  * @param cpusubtype Mach-O style CPU subtype
1016  * @return whether the CPU subtype matches arm64e with the current ptrauth ABI
1017  */
1018 static inline bool
arm64_cpusubtype_uses_ptrauth(cpu_subtype_t cpusubtype)1019 arm64_cpusubtype_uses_ptrauth(cpu_subtype_t cpusubtype)
1020 {
1021 	return (cpusubtype & ~CPU_SUBTYPE_MASK) == CPU_SUBTYPE_ARM64E &&
1022 	       CPU_SUBTYPE_ARM64_PTR_AUTH_VERSION(cpusubtype) == CPU_SUBTYPE_ARM64_PTR_AUTH_CURRENT_VERSION;
1023 }
1024 
1025 #endif /* __has_feature(ptrauth_calls) */
1026 
1027 /**
1028  * Returns whether a type/subtype slice matches the requested
1029  * type/subtype.
1030  *
1031  * @param mask Bits to mask from the requested/tested cpu type
1032  * @param req_cpu Requested cpu type
1033  * @param req_subcpu Requested cpu subtype
1034  * @param test_cpu Tested slice cpu type
1035  * @param test_subcpu Tested slice cpu subtype
1036  */
1037 boolean_t
binary_match(cpu_type_t mask,cpu_type_t req_cpu,cpu_subtype_t req_subcpu,cpu_type_t test_cpu,cpu_subtype_t test_subcpu)1038 binary_match(cpu_type_t mask, cpu_type_t req_cpu,
1039     cpu_subtype_t req_subcpu, cpu_type_t test_cpu,
1040     cpu_subtype_t test_subcpu)
1041 {
1042 	if ((test_cpu & ~mask) != (req_cpu & ~mask)) {
1043 		return FALSE;
1044 	}
1045 
1046 	test_subcpu &= ~CPU_SUBTYPE_MASK;
1047 	req_subcpu  &= ~CPU_SUBTYPE_MASK;
1048 
1049 	if (test_subcpu != req_subcpu && req_subcpu != (CPU_SUBTYPE_ANY & ~CPU_SUBTYPE_MASK)) {
1050 		return FALSE;
1051 	}
1052 
1053 	return TRUE;
1054 }
1055 
1056 
1057 // Check entitlements to see if this is a hardened runtime binary.
1058 // Save this in load_result until later for two purposes:
1059 // 1. Once the task is created, we can mark it as hardened runtime if needed
1060 // 2. we can propagate which entitlements are present to the apple array
1061 static inline void
encode_HR_entitlement(const char * entitlement,HR_flags_t mask,const struct image_params * imgp,load_result_t * load_result)1062 encode_HR_entitlement(const char *entitlement, HR_flags_t mask,
1063     const struct image_params *imgp, load_result_t *load_result)
1064 {
1065 	if (IOVnodeHasEntitlement(imgp->ip_vp, (int64_t)imgp->ip_arch_offset, entitlement)) {
1066 		load_result->hardened_runtime_binary |= mask;
1067 	}
1068 }
1069 
1070 /*
1071  * If the passed in executable's vnode should use the RSR
1072  * shared region, then this should return TRUE, otherwise, return FALSE.
1073  */
1074 static uint32_t rsr_current_version = 0;
1075 boolean_t (*rsr_check_vnode)(void *vnode) = NULL;
1076 
1077 boolean_t
vnode_is_rsr(vnode_t vp)1078 vnode_is_rsr(vnode_t vp)
1079 {
1080 	if (!(vnode_isreg(vp) && vnode_tag(vp) == VT_APFS)) {
1081 		return FALSE;
1082 	}
1083 
1084 	if (rsr_check_vnode != NULL && rsr_check_vnode((void *)vp)) {
1085 		return TRUE;
1086 	}
1087 	return FALSE;
1088 }
1089 
1090 /* Runtime security mitigations */
1091 
1092 /*
1093  * Hardened-process.
1094  *
1095  * Security mitigations follow the notion of "hardened-process": binaries that we
1096  * have identified as being security critical. They are identified by the
1097  * com.apple.developer.hardened-process entitlement, which is required to further
1098  * configure the other security mitigations.
1099  */
1100 #define SPAWN_ENABLE_HARDENED_PROCESS "com.apple.developer.hardened-process"
1101 
1102 /*
1103  * Hardened-Heap.
1104  *
1105  * This mitigation extends libmalloc xzone with a number of security features,
1106  * most notably increasing the number of buckets and adding guard pages.
1107  * The presence of the entitlement opts the binary into the feature.
1108  */
1109 #define SPAWN_ENABLE_HARDENED_HEAP "com.apple.developer.hardened-process.hardened-heap"
1110 
1111 
1112 
1113 /*
1114  * Enablement of hardened-heap is pretty straightforward and solely depends on
1115  * the presence of the associated entitlement.
1116  */
1117 static inline void
exec_setup_hardened_heap(struct image_params * imgp,task_t task)1118 exec_setup_hardened_heap(struct image_params *imgp, task_t task)
1119 {
1120 	if (IOVnodeHasEntitlement(imgp->ip_vp, (int64_t)imgp->ip_arch_offset,
1121 	    SPAWN_ENABLE_HARDENED_HEAP)) {
1122 		task_set_hardened_heap(task);
1123 	}
1124 }
1125 
1126 
1127 
1128 /*
1129  * This routine configures the various runtime mitigations we can apply to a process.
1130  * Returns true on success, false on failure. Failure will be fatal in exec_mach_imgact().
1131  */
1132 static inline errno_t
exec_setup_runtime_mitigations(struct image_params * imgp,__unused load_result_t * load_result,__unused task_t old_task,task_t new_task,__unused vm_map_t map,__unused proc_t proc)1133 exec_setup_runtime_mitigations(struct image_params *imgp, __unused load_result_t *load_result,
1134     __unused task_t old_task, task_t new_task, __unused vm_map_t map, __unused proc_t proc)
1135 {
1136 	errno_t retval = 0;
1137 
1138 	/*
1139 	 * Hardened-heap enables a set of extra security features in our system memory allocator.
1140 	 */
1141 	exec_setup_hardened_heap(imgp, new_task);
1142 
1143 
1144 	return retval;
1145 }
1146 
1147 uint32_t
rsr_get_version(void)1148 rsr_get_version(void)
1149 {
1150 	return os_atomic_load(&rsr_current_version, relaxed);
1151 }
1152 
1153 void
rsr_bump_version(void)1154 rsr_bump_version(void)
1155 {
1156 	os_atomic_inc(&rsr_current_version, relaxed);
1157 }
1158 
1159 #if XNU_TARGET_OS_OSX
1160 static int
1161 rsr_version_sysctl SYSCTL_HANDLER_ARGS
1162 {
1163 #pragma unused(arg1, arg2, oidp)
1164 	int value = rsr_get_version();
1165 	int error = SYSCTL_OUT(req, &value, sizeof(int));
1166 	if (error) {
1167 		return error;
1168 	}
1169 
1170 	if (!req->newptr) {
1171 		return 0;
1172 	}
1173 
1174 	error = SYSCTL_IN(req, &value, sizeof(int));
1175 	if (error) {
1176 		return error;
1177 	}
1178 	if (value != 0) {
1179 		rsr_bump_version();
1180 	}
1181 	return 0;
1182 }
1183 
1184 
1185 SYSCTL_PROC(_vm, OID_AUTO, shared_region_control,
1186     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED | CTLFLAG_MASKED,
1187     0, 0, rsr_version_sysctl, "I", "");
1188 #endif /* XNU_TARGET_OS_OSX */
1189 
1190 /*
1191  * exec_mach_imgact
1192  *
1193  * Image activator for mach-o 1.0 binaries.
1194  *
1195  * Parameters;	struct image_params *	image parameter block
1196  *
1197  * Returns:	-1			not a fat binary (keep looking)
1198  *		-2			Success: encapsulated binary: reread
1199  *		>0			Failure: error number
1200  *		EBADARCH		Mach-o binary, but with an unrecognized
1201  *					architecture
1202  *		ENOMEM			No memory for child process after -
1203  *					can only happen after vfork()
1204  *
1205  * Important:	This image activator is NOT byte order neutral.
1206  *
1207  * Note:	A return value other than -1 indicates subsequent image
1208  *		activators should not be given the opportunity to attempt
1209  *		to activate the image.
1210  */
1211 static int
exec_mach_imgact(struct image_params * imgp)1212 exec_mach_imgact(struct image_params *imgp)
1213 {
1214 	struct mach_header *mach_header = (struct mach_header *)imgp->ip_vdata;
1215 	proc_t                  p = vfs_context_proc(imgp->ip_vfs_context);
1216 	int                     error = 0;
1217 	task_t                  task;
1218 	task_t                  new_task = NULL;    /* protected by vfexec */
1219 	thread_t                thread;
1220 	struct uthread          *uthread;
1221 	vm_map_switch_context_t switch_ctx;
1222 	vm_map_t old_map = VM_MAP_NULL;
1223 	vm_map_t map = VM_MAP_NULL;
1224 	load_return_t           lret;
1225 	load_result_t           load_result = {};
1226 	struct _posix_spawnattr *psa = NULL;
1227 	int                     spawn = (imgp->ip_flags & IMGPF_SPAWN);
1228 	const int               vfexec = 0;
1229 	int                     exec = (imgp->ip_flags & IMGPF_EXEC);
1230 	os_reason_t             exec_failure_reason = OS_REASON_NULL;
1231 	boolean_t               reslide = FALSE;
1232 	char *                  userspace_coredump_name = NULL;
1233 
1234 	/*
1235 	 * make sure it's a Mach-O 1.0 or Mach-O 2.0 binary; the difference
1236 	 * is a reserved field on the end, so for the most part, we can
1237 	 * treat them as if they were identical. Reverse-endian Mach-O
1238 	 * binaries are recognized but not compatible.
1239 	 */
1240 	if ((mach_header->magic == MH_CIGAM) ||
1241 	    (mach_header->magic == MH_CIGAM_64)) {
1242 		error = EBADARCH;
1243 		goto bad;
1244 	}
1245 
1246 	if ((mach_header->magic != MH_MAGIC) &&
1247 	    (mach_header->magic != MH_MAGIC_64)) {
1248 		error = -1;
1249 		goto bad;
1250 	}
1251 
1252 	if (mach_header->filetype != MH_EXECUTE) {
1253 		error = -1;
1254 		goto bad;
1255 	}
1256 
1257 	if (imgp->ip_origcputype != 0) {
1258 		/* Fat header previously had an idea about this thin file */
1259 		if (imgp->ip_origcputype != mach_header->cputype ||
1260 		    imgp->ip_origcpusubtype != mach_header->cpusubtype) {
1261 			error = EBADARCH;
1262 			goto bad;
1263 		}
1264 	} else {
1265 		imgp->ip_origcputype = mach_header->cputype;
1266 		imgp->ip_origcpusubtype = mach_header->cpusubtype;
1267 	}
1268 
1269 	task = current_task();
1270 	thread = current_thread();
1271 	uthread = get_bsdthread_info(thread);
1272 
1273 	if ((mach_header->cputype & CPU_ARCH_ABI64) == CPU_ARCH_ABI64) {
1274 		imgp->ip_flags |= IMGPF_IS_64BIT_ADDR | IMGPF_IS_64BIT_DATA;
1275 	}
1276 
1277 
1278 	/* If posix_spawn binprefs exist, respect those prefs. */
1279 	psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
1280 	if (psa != NULL && psa->psa_binprefs[0] != 0) {
1281 		int pr = 0;
1282 		for (pr = 0; pr < NBINPREFS; pr++) {
1283 			cpu_type_t pref = psa->psa_binprefs[pr];
1284 			cpu_subtype_t subpref = psa->psa_subcpuprefs[pr];
1285 
1286 			if (pref == 0) {
1287 				/* No suitable arch in the pref list */
1288 				error = EBADARCH;
1289 				goto bad;
1290 			}
1291 
1292 			if (pref == CPU_TYPE_ANY) {
1293 				/* Jump to regular grading */
1294 				goto grade;
1295 			}
1296 
1297 			if (binary_match(CPU_ARCH_MASK, pref, subpref,
1298 			    imgp->ip_origcputype, imgp->ip_origcpusubtype)) {
1299 				goto grade;
1300 			}
1301 		}
1302 		error = EBADARCH;
1303 		goto bad;
1304 	}
1305 grade:
1306 	if (!grade_binary(imgp->ip_origcputype, imgp->ip_origcpusubtype & ~CPU_SUBTYPE_MASK,
1307 	    imgp->ip_origcpusubtype & CPU_SUBTYPE_MASK, TRUE)) {
1308 		error = EBADARCH;
1309 		goto bad;
1310 	}
1311 
1312 	if (validate_potential_simulator_binary(imgp->ip_origcputype, imgp,
1313 	    imgp->ip_arch_offset, imgp->ip_arch_size) != LOAD_SUCCESS) {
1314 #if __x86_64__
1315 		const char *excpath;
1316 		error = exec_save_path(imgp, imgp->ip_user_fname, imgp->ip_seg, &excpath);
1317 		os_log_error(OS_LOG_DEFAULT, "Unsupported 32-bit executable: \"%s\"", (error) ? imgp->ip_vp->v_name : excpath);
1318 #endif
1319 		error = EBADARCH;
1320 		goto bad;
1321 	}
1322 
1323 #if defined(HAS_APPLE_PAC)
1324 	assert(mach_header->cputype == CPU_TYPE_ARM64
1325 	    );
1326 
1327 	if ((mach_header->cputype == CPU_TYPE_ARM64 &&
1328 	    arm64_cpusubtype_uses_ptrauth(mach_header->cpusubtype))
1329 	    ) {
1330 		imgp->ip_flags &= ~IMGPF_NOJOP;
1331 	} else {
1332 		imgp->ip_flags |= IMGPF_NOJOP;
1333 	}
1334 #endif
1335 
1336 	/* Copy in arguments/environment from the old process */
1337 	error = exec_extract_strings(imgp);
1338 	if (error) {
1339 		goto bad;
1340 	}
1341 
1342 	AUDIT_ARG(argv, imgp->ip_startargv, imgp->ip_argc,
1343 	    imgp->ip_endargv - imgp->ip_startargv);
1344 	AUDIT_ARG(envv, imgp->ip_endargv, imgp->ip_envc,
1345 	    imgp->ip_endenvv - imgp->ip_endargv);
1346 
1347 	/* reset local idea of thread, uthread, task */
1348 	thread = imgp->ip_new_thread;
1349 	uthread = get_bsdthread_info(thread);
1350 	task = new_task = get_threadtask(thread);
1351 
1352 	/*
1353 	 *	Load the Mach-O file.
1354 	 *
1355 	 * NOTE: An error after this point  indicates we have potentially
1356 	 * destroyed or overwritten some process state while attempting an
1357 	 * execve() following a vfork(), which is an unrecoverable condition.
1358 	 * We send the new process an immediate SIGKILL to avoid it executing
1359 	 * any instructions in the mutated address space. For true spawns,
1360 	 * this is not the case, and "too late" is still not too late to
1361 	 * return an error code to the parent process.
1362 	 */
1363 
1364 	/*
1365 	 * Actually load the image file we previously decided to load.
1366 	 */
1367 	lret = load_machfile(imgp, mach_header, thread, &map, &load_result);
1368 	if (lret != LOAD_SUCCESS) {
1369 		error = load_return_to_errno(lret);
1370 
1371 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1372 		    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_MACHO, 0, 0);
1373 		if (lret == LOAD_BADMACHO_UPX) {
1374 			set_proc_name(imgp, p);
1375 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_UPX);
1376 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1377 		} else {
1378 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_MACHO);
1379 
1380 			if (bootarg_execfailurereports) {
1381 				set_proc_name(imgp, p);
1382 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1383 			}
1384 		}
1385 
1386 		exec_failure_reason->osr_flags |= OS_REASON_FLAG_CONSISTENT_FAILURE;
1387 
1388 		goto badtoolate;
1389 	}
1390 
1391 	assert(imgp->ip_free_map == NULL);
1392 
1393 
1394 	// It's safe to check entitlements anytime after `load_machfile` if you check
1395 	// based on the vnode in imgp. We must perform this entitlement check
1396 	// before we start using load_result->hardened_runtime_binary further down
1397 	load_result.hardened_runtime_binary = 0;
1398 	encode_HR_entitlement(kCSWebBrowserHostEntitlement, BrowserHostEntitlementMask, imgp, &load_result);
1399 	encode_HR_entitlement(kCSWebBrowserGPUEntitlement, BrowserGPUEntitlementMask, imgp, &load_result);
1400 	encode_HR_entitlement(kCSWebBrowserNetworkEntitlement, BrowserNetworkEntitlementMask, imgp, &load_result);
1401 	encode_HR_entitlement(kCSWebBrowserWebContentEntitlement, BrowserWebContentEntitlementMask, imgp, &load_result);
1402 
1403 	/*
1404 	 * ERROR RECOVERY
1405 	 *
1406 	 * load_machfile() returned the new VM map ("map") but we haven't
1407 	 * committed to it yet.
1408 	 * Any error path between here and the point where we commit to using
1409 	 * the new "map" (with swap_task_map()) should deallocate "map".
1410 	 */
1411 
1412 #ifndef KASAN
1413 	/*
1414 	 * Security: zone sanity checks on fresh boot or initproc re-exec.
1415 	 * launchd by design does not tear down its own service port on USR (rdar://72797967),
1416 	 * which means here is the earliest point we can assert on empty service port label zone,
1417 	 * after load_machfile() above terminates old launchd's IPC space.
1418 	 *
1419 	 * Disable on KASAN builds since zone_size_allocated() accounts for elements
1420 	 * under quarantine.
1421 	 */
1422 	if (task_pid(task) == 1) {
1423 		zone_userspace_reboot_checks();
1424 	}
1425 #endif
1426 
1427 	proc_lock(p);
1428 	p->p_cputype = imgp->ip_origcputype;
1429 	p->p_cpusubtype = imgp->ip_origcpusubtype;
1430 	proc_setplatformdata(p, load_result.ip_platform, load_result.lr_min_sdk, load_result.lr_sdk);
1431 
1432 	vm_map_set_size_limit(map, proc_limitgetcur(p, RLIMIT_AS));
1433 	vm_map_set_data_limit(map, proc_limitgetcur(p, RLIMIT_DATA));
1434 	vm_map_set_user_wire_limit(map, (vm_size_t)proc_limitgetcur(p, RLIMIT_MEMLOCK));
1435 
1436 #if XNU_TARGET_OS_OSX
1437 	if (proc_platform(p) == PLATFORM_IOS) {
1438 		assert(vm_map_is_alien(map));
1439 	} else {
1440 		assert(!vm_map_is_alien(map));
1441 	}
1442 #endif /* XNU_TARGET_OS_OSX */
1443 	proc_unlock(p);
1444 
1445 	/*
1446 	 * Setup runtime mitigations.
1447 	 */
1448 	if ((error = exec_setup_runtime_mitigations(imgp, &load_result, current_task(), new_task, map, p)) != 0) {
1449 		set_proc_name(imgp, p);
1450 		exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_MACHO);
1451 		if (bootarg_execfailurereports) {
1452 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1453 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_CONSISTENT_FAILURE;
1454 		}
1455 		/* release new address space since we won't use it */
1456 		imgp->ip_free_map = map;
1457 		map = VM_MAP_NULL;
1458 		goto badtoolate;
1459 	}
1460 
1461 	/*
1462 	 * Set code-signing flags if this binary is signed, or if parent has
1463 	 * requested them on exec.
1464 	 */
1465 	if (load_result.csflags & CS_VALID) {
1466 		imgp->ip_csflags |= load_result.csflags &
1467 		    (CS_VALID | CS_SIGNED | CS_DEV_CODE | CS_LINKER_SIGNED |
1468 		    CS_HARD | CS_KILL | CS_RESTRICT | CS_ENFORCEMENT | CS_REQUIRE_LV |
1469 		    CS_FORCED_LV | CS_ENTITLEMENTS_VALIDATED | CS_NO_UNTRUSTED_HELPERS | CS_RUNTIME |
1470 		    CS_ENTITLEMENT_FLAGS |
1471 		    CS_EXEC_SET_HARD | CS_EXEC_SET_KILL | CS_EXEC_SET_ENFORCEMENT);
1472 	} else {
1473 		imgp->ip_csflags &= ~CS_VALID;
1474 	}
1475 
1476 	if (proc_getcsflags(p) & CS_EXEC_SET_HARD) {
1477 		imgp->ip_csflags |= CS_HARD;
1478 	}
1479 	if (proc_getcsflags(p) & CS_EXEC_SET_KILL) {
1480 		imgp->ip_csflags |= CS_KILL;
1481 	}
1482 	if (proc_getcsflags(p) & CS_EXEC_SET_ENFORCEMENT) {
1483 		imgp->ip_csflags |= CS_ENFORCEMENT;
1484 	}
1485 	if (proc_getcsflags(p) & CS_EXEC_INHERIT_SIP) {
1486 		if (proc_getcsflags(p) & CS_INSTALLER) {
1487 			imgp->ip_csflags |= CS_INSTALLER;
1488 		}
1489 		if (proc_getcsflags(p) & CS_DATAVAULT_CONTROLLER) {
1490 			imgp->ip_csflags |= CS_DATAVAULT_CONTROLLER;
1491 		}
1492 		if (proc_getcsflags(p) & CS_NVRAM_UNRESTRICTED) {
1493 			imgp->ip_csflags |= CS_NVRAM_UNRESTRICTED;
1494 		}
1495 	}
1496 
1497 #if __has_feature(ptrauth_calls) && defined(XNU_TARGET_OS_OSX)
1498 	/*
1499 	 * ptrauth version 0 is a preview ABI.  Developers can opt into running
1500 	 * their own arm64e binaries for local testing, with the understanding
1501 	 * that future OSes may break ABI.
1502 	 */
1503 	if ((imgp->ip_origcpusubtype & ~CPU_SUBTYPE_MASK) == CPU_SUBTYPE_ARM64E &&
1504 	    CPU_SUBTYPE_ARM64_PTR_AUTH_VERSION(imgp->ip_origcpusubtype) == 0 &&
1505 	    !load_result.platform_binary &&
1506 	    !bootarg_arm64e_preview_abi) {
1507 		static bool logged_once = false;
1508 		set_proc_name(imgp, p);
1509 
1510 		printf("%s: not running binary \"%s\" built against preview arm64e ABI\n", __func__, p->p_name);
1511 		if (!os_atomic_xchg(&logged_once, true, relaxed)) {
1512 			printf("%s: (to allow this, add \"-arm64e_preview_abi\" to boot-args)\n", __func__);
1513 		}
1514 
1515 		exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_MACHO);
1516 		if (bootarg_execfailurereports) {
1517 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1518 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_CONSISTENT_FAILURE;
1519 		}
1520 
1521 		/* release new address space since we won't use it */
1522 		imgp->ip_free_map = map;
1523 		map = VM_MAP_NULL;
1524 		goto badtoolate;
1525 	}
1526 
1527 	if ((imgp->ip_origcpusubtype & ~CPU_SUBTYPE_MASK) != CPU_SUBTYPE_ARM64E &&
1528 	    imgp->ip_origcputype == CPU_TYPE_ARM64 &&
1529 	    load_result.platform_binary &&
1530 	    (imgp->ip_flags & IMGPF_DRIVER) != 0) {
1531 		set_proc_name(imgp, p);
1532 		printf("%s: disallowing arm64 platform driverkit binary \"%s\", should be arm64e\n", __func__, p->p_name);
1533 		exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_MACHO);
1534 		if (bootarg_execfailurereports) {
1535 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1536 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_CONSISTENT_FAILURE;
1537 		}
1538 
1539 		/* release new address space since we won't use it */
1540 		imgp->ip_free_map = map;
1541 		map = VM_MAP_NULL;
1542 		goto badtoolate;
1543 	}
1544 #endif /* __has_feature(ptrauth_calls) && defined(XNU_TARGET_OS_OSX) */
1545 
1546 
1547 
1548 	/*
1549 	 * Set up the shared cache region in the new process.
1550 	 *
1551 	 * Normally there is a single shared region per architecture.
1552 	 * However on systems with Pointer Authentication, we can create
1553 	 * multiple shared caches with the amount of sharing determined
1554 	 * by team-id or entitlement. Inherited shared region IDs are used
1555 	 * for system processes that need to match and be able to inspect
1556 	 * a pre-existing task.
1557 	 */
1558 	int cpu_subtype = 0;     /* all cpu_subtypes use the same shared region */
1559 #if __has_feature(ptrauth_calls)
1560 	char *shared_region_id = NULL;
1561 	size_t len;
1562 	char *base;
1563 	const char *cbase;
1564 #define HARDENED_RUNTIME_CONTENT_ID "C-"
1565 #define TEAM_ID_PREFIX "T-"
1566 #define ENTITLE_PREFIX "E-"
1567 #define SR_PREFIX_LEN  2
1568 #define SR_ENTITLEMENT "com.apple.pac.shared_region_id"
1569 
1570 	if (cpu_type() == CPU_TYPE_ARM64 &&
1571 	    arm64_cpusubtype_uses_ptrauth(p->p_cpusubtype) &&
1572 	    (imgp->ip_flags & IMGPF_NOJOP) == 0) {
1573 		assertf(p->p_cputype == CPU_TYPE_ARM64,
1574 		    "p %p cpu_type() 0x%x p->p_cputype 0x%x p->p_cpusubtype 0x%x",
1575 		    p, cpu_type(), p->p_cputype, p->p_cpusubtype);
1576 
1577 		/*
1578 		 * arm64e uses pointer authentication, so request a separate
1579 		 * shared region for this CPU subtype.
1580 		 */
1581 		cpu_subtype = p->p_cpusubtype & ~CPU_SUBTYPE_MASK;
1582 
1583 		/*
1584 		 * Determine which shared cache to select based on being told,
1585 		 * matching a team-id or matching an entitlement.
1586 		 */
1587 		if (load_result.hardened_runtime_binary & BrowserWebContentEntitlementMask) {
1588 			len = sizeof(HARDENED_RUNTIME_CONTENT_ID);
1589 			shared_region_id = kalloc_data(len, Z_WAITOK | Z_NOFAIL);
1590 			strlcpy(shared_region_id, HARDENED_RUNTIME_CONTENT_ID, len);
1591 		} else if (imgp->ip_inherited_shared_region_id) {
1592 			len = strlen(imgp->ip_inherited_shared_region_id);
1593 			shared_region_id = kalloc_data(len + 1, Z_WAITOK | Z_NOFAIL);
1594 			memcpy(shared_region_id, imgp->ip_inherited_shared_region_id, len + 1);
1595 		} else if ((cbase = get_teamid_for_shared_region(imgp)) != NULL) {
1596 			len = strlen(cbase);
1597 			if (vm_shared_region_per_team_id) {
1598 				shared_region_id = kalloc_data(len + SR_PREFIX_LEN + 1,
1599 				    Z_WAITOK | Z_NOFAIL);
1600 				memcpy(shared_region_id, TEAM_ID_PREFIX, SR_PREFIX_LEN);
1601 				memcpy(shared_region_id + SR_PREFIX_LEN, cbase, len + 1);
1602 			}
1603 		} else if ((base = IOVnodeGetEntitlement(imgp->ip_vp,
1604 		    (int64_t)imgp->ip_arch_offset, SR_ENTITLEMENT)) != NULL) {
1605 			len = strlen(base);
1606 			if (vm_shared_region_by_entitlement) {
1607 				shared_region_id = kalloc_data(len + SR_PREFIX_LEN + 1,
1608 				    Z_WAITOK | Z_NOFAIL);
1609 				memcpy(shared_region_id, ENTITLE_PREFIX, SR_PREFIX_LEN);
1610 				memcpy(shared_region_id + SR_PREFIX_LEN, base, len + 1);
1611 			}
1612 			/* Discard the copy of the entitlement */
1613 			kfree_data(base, len + 1);
1614 		}
1615 	}
1616 
1617 	if (imgp->ip_flags & IMGPF_RESLIDE) {
1618 		reslide = TRUE;
1619 	}
1620 
1621 	/* use "" as the default shared_region_id */
1622 	if (shared_region_id == NULL) {
1623 		shared_region_id = kalloc_data(1, Z_WAITOK | Z_ZERO | Z_NOFAIL);
1624 	}
1625 
1626 	/* ensure there's a unique pointer signing key for this shared_region_id */
1627 	shared_region_key_alloc(shared_region_id,
1628 	    imgp->ip_inherited_shared_region_id != NULL, imgp->ip_inherited_jop_pid);
1629 	task_set_shared_region_id(task, shared_region_id);
1630 	shared_region_id = NULL;
1631 #endif /* __has_feature(ptrauth_calls) */
1632 
1633 #if CONFIG_ROSETTA
1634 	if (imgp->ip_flags & IMGPF_ROSETTA) {
1635 		OSBitOrAtomic(P_TRANSLATED, &p->p_flag);
1636 	} else if (p->p_flag & P_TRANSLATED) {
1637 		OSBitAndAtomic(~P_TRANSLATED, &p->p_flag);
1638 	}
1639 #endif
1640 
1641 	int cputype = cpu_type();
1642 
1643 	uint32_t rsr_version = 0;
1644 #if XNU_TARGET_OS_OSX
1645 	if (vnode_is_rsr(imgp->ip_vp)) {
1646 		rsr_version = rsr_get_version();
1647 		os_atomic_or(&p->p_ladvflag, P_RSR, relaxed);
1648 		os_atomic_or(&p->p_vfs_iopolicy, P_VFS_IOPOLICY_ALTLINK, relaxed);
1649 	}
1650 #endif /* XNU_TARGET_OS_OSX */
1651 
1652 	error = vm_map_exec(map, task, load_result.is_64bit_addr,
1653 	    (void *)p->p_fd.fd_rdir, cputype, cpu_subtype, reslide,
1654 	    (imgp->ip_flags & IMGPF_DRIVER) != 0,
1655 	    rsr_version);
1656 
1657 	if (error) {
1658 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1659 		    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_MAP_EXEC_FAILURE, 0, 0);
1660 
1661 		exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_MAP_EXEC_FAILURE);
1662 		if (bootarg_execfailurereports) {
1663 			set_proc_name(imgp, p);
1664 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1665 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_CONSISTENT_FAILURE;
1666 		}
1667 		/* release new address space since we won't use it */
1668 		imgp->ip_free_map = map;
1669 		map = VM_MAP_NULL;
1670 		goto badtoolate;
1671 	}
1672 
1673 	/*
1674 	 * Close file descriptors which specify close-on-exec.
1675 	 */
1676 	fdt_exec(p, vfs_context_ucred(imgp->ip_vfs_context),
1677 	    psa != NULL ? psa->psa_flags : 0, imgp->ip_new_thread, exec);
1678 
1679 	/*
1680 	 * deal with set[ug]id.
1681 	 */
1682 	error = exec_handle_sugid(imgp);
1683 	if (error) {
1684 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1685 		    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_SUGID_FAILURE, 0, 0);
1686 
1687 		exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_SUGID_FAILURE);
1688 		if (bootarg_execfailurereports) {
1689 			set_proc_name(imgp, p);
1690 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1691 		}
1692 
1693 		/* release new address space since we won't use it */
1694 		imgp->ip_free_map = map;
1695 		map = VM_MAP_NULL;
1696 		goto badtoolate;
1697 	}
1698 
1699 	/*
1700 	 * Commit to new map.
1701 	 *
1702 	 * Swap the new map for the old for target task, which consumes
1703 	 * our new map reference but each leaves us responsible for the
1704 	 * old_map reference.  That lets us get off the pmap associated
1705 	 * with it, and then we can release it.
1706 	 *
1707 	 * The map needs to be set on the target task which is different
1708 	 * than current task, thus swap_task_map is used instead of
1709 	 * vm_map_switch.
1710 	 */
1711 	old_map = swap_task_map(task, thread, map);
1712 #if MACH_ASSERT
1713 	/*
1714 	 * Reset the pmap's process info to prevent ledger checks
1715 	 * which might fail due to the ledgers being shared between
1716 	 * the old and new pmaps.
1717 	 */
1718 	vm_map_pmap_set_process(old_map, -1, "<old_map>");
1719 #endif /* MACH_ASSERT */
1720 	imgp->ip_free_map = old_map;
1721 	old_map = NULL;
1722 
1723 	lret = activate_exec_state(task, p, thread, &load_result);
1724 	if (lret != KERN_SUCCESS) {
1725 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1726 		    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_ACTV_THREADSTATE, 0, 0);
1727 
1728 		exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_ACTV_THREADSTATE);
1729 		if (bootarg_execfailurereports) {
1730 			set_proc_name(imgp, p);
1731 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1732 		}
1733 
1734 		goto badtoolate;
1735 	}
1736 
1737 	/*
1738 	 * deal with voucher on exec-calling thread.
1739 	 */
1740 	if (imgp->ip_new_thread == NULL) {
1741 		thread_set_mach_voucher(current_thread(), IPC_VOUCHER_NULL);
1742 	}
1743 
1744 	/* Make sure we won't interrupt ourself signalling a partial process */
1745 	if (!vfexec && !spawn && (p->p_lflag & P_LTRACED)) {
1746 		psignal(p, SIGTRAP);
1747 	}
1748 
1749 	if (load_result.unixproc &&
1750 	    create_unix_stack(get_task_map(task),
1751 	    &load_result,
1752 	    p) != KERN_SUCCESS) {
1753 		error = load_return_to_errno(LOAD_NOSPACE);
1754 
1755 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1756 		    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_STACK_ALLOC, 0, 0);
1757 
1758 		exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_STACK_ALLOC);
1759 		if (bootarg_execfailurereports) {
1760 			set_proc_name(imgp, p);
1761 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1762 		}
1763 
1764 		goto badtoolate;
1765 	}
1766 
1767 	if (load_result.hardened_runtime_binary) {
1768 		if (cs_debug) {
1769 			printf("setting hardened runtime with entitlement mask= "
1770 			    "0x%x on task: pid = %d\n",
1771 			    load_result.hardened_runtime_binary,
1772 			    proc_getpid(p));
1773 		}
1774 		task_set_hardened_runtime(task, true);
1775 	}
1776 
1777 	/*
1778 	 * The load result will have already been munged by AMFI to include the
1779 	 * platform binary flag if boot-args dictated it (AMFI will mark anything
1780 	 * that doesn't go through the upcall path as a platform binary if its
1781 	 * enforcement is disabled).
1782 	 */
1783 	if (load_result.platform_binary) {
1784 		if (cs_debug) {
1785 			printf("setting platform binary on task: pid = %d\n", proc_getpid(p));
1786 		}
1787 
1788 		/*
1789 		 * We must use 'task' here because the proc's task has not yet been
1790 		 * switched to the new one.
1791 		 */
1792 		task_set_platform_binary(task, TRUE);
1793 	} else {
1794 		if (cs_debug) {
1795 			printf("clearing platform binary on task: pid = %d\n", proc_getpid(p));
1796 		}
1797 
1798 		task_set_platform_binary(task, FALSE);
1799 	}
1800 
1801 #if XNU_TARGET_OS_OSX
1802 	/* Disable mach hardening for all 1P tasks which load 3P plugins */
1803 	if (imgp->ip_flags & IMGPF_3P_PLUGINS) {
1804 		if (cs_debug) {
1805 			printf("Disabling some mach hardening on task due to 3P plugins: pid = %d\n", proc_getpid(p));
1806 		}
1807 		task_disable_mach_hardening(task);
1808 	}
1809 #if DEVELOPMENT || DEBUG
1810 	/* Disable mach hardening for all tasks if amfi_get_out_of_my_way is set.
1811 	 * Customers will have to turn SIP off to use this boot-arg, and so this is
1812 	 * only needed internally since we disable this feature when SIP is off. */
1813 	if (AMFI_bootarg_disable_mach_hardening) {
1814 		if (cs_debug) {
1815 			printf("Disabling some mach hardening on task due to AMFI boot-args: pid = %d\n", proc_getpid(p));
1816 		}
1817 		task_disable_mach_hardening(task);
1818 	}
1819 #endif /* DEVELOPMENT || DEBUG */
1820 #endif /* XNU_TARGET_OS_OSX */
1821 
1822 	/*
1823 	 * Set starting EXC_GUARD and control port behavior for task now that
1824 	 * platform and hardened runtime is set. Use the name directly from imgp since we haven't
1825 	 * set_proc_name() yet. Also make control port for the task and main thread
1826 	 * immovable/pinned based on task's option.
1827 	 *
1828 	 * Must happen before main thread port copyout in exc_add_apple_strings.
1829 	 */
1830 	task_set_exc_guard_ctrl_port_default(task, thread,
1831 	    imgp->ip_ndp->ni_cnd.cn_nameptr,
1832 	    (unsigned)imgp->ip_ndp->ni_cnd.cn_namelen,
1833 	    proc_is_simulated(p),
1834 	    load_result.ip_platform,
1835 	    load_result.lr_sdk);
1836 
1837 	error = exec_add_apple_strings(imgp, &load_result, task);     /* copies out main thread port */
1838 
1839 	if (error) {
1840 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1841 		    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_APPLE_STRING_INIT, 0, 0);
1842 
1843 		exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_APPLE_STRING_INIT);
1844 		if (bootarg_execfailurereports) {
1845 			set_proc_name(imgp, p);
1846 			exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1847 		}
1848 		goto badtoolate;
1849 	}
1850 
1851 	/* Switch to target task's map to copy out strings */
1852 	switch_ctx = vm_map_switch_to(get_task_map(task));
1853 
1854 	if (load_result.unixproc) {
1855 		user_addr_t     ap;
1856 
1857 		/*
1858 		 * Copy the strings area out into the new process address
1859 		 * space.
1860 		 */
1861 		ap = p->user_stack;
1862 		error = exec_copyout_strings(imgp, &ap);
1863 		if (error) {
1864 			vm_map_switch_back(switch_ctx);
1865 
1866 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1867 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_STRINGS, 0, 0);
1868 
1869 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_STRINGS);
1870 			if (bootarg_execfailurereports) {
1871 				set_proc_name(imgp, p);
1872 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1873 			}
1874 			goto badtoolate;
1875 		}
1876 		/* Set the stack */
1877 		thread_setuserstack(thread, ap);
1878 	}
1879 
1880 	if (load_result.dynlinker || load_result.is_rosetta) {
1881 		user_addr_t        ap;
1882 		int                     new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) ? 8 : 4;
1883 
1884 		/* Adjust the stack */
1885 		ap = thread_adjuserstack(thread, -new_ptr_size);
1886 		error = copyoutptr(load_result.mach_header, ap, new_ptr_size);
1887 
1888 		if (error) {
1889 			vm_map_switch_back(switch_ctx);
1890 
1891 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1892 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_DYNLINKER, 0, 0);
1893 
1894 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_DYNLINKER);
1895 			if (bootarg_execfailurereports) {
1896 				set_proc_name(imgp, p);
1897 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1898 			}
1899 			goto badtoolate;
1900 		}
1901 		error = task_set_dyld_info(task, load_result.all_image_info_addr,
1902 		    load_result.all_image_info_size, false);
1903 		if (error) {
1904 			vm_map_switch_back(switch_ctx);
1905 
1906 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1907 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_SET_DYLD_INFO, 0, 0);
1908 
1909 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_SET_DYLD_INFO);
1910 			if (bootarg_execfailurereports) {
1911 				set_proc_name(imgp, p);
1912 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1913 			}
1914 			error = EINVAL;
1915 			goto badtoolate;
1916 		}
1917 	} else {
1918 		/*
1919 		 * No dyld or rosetta loaded, set the TF_DYLD_ALL_IMAGE_FINAL bit on task.
1920 		 */
1921 		error = task_set_dyld_info(task, MACH_VM_MIN_ADDRESS,
1922 		    0, true);
1923 		if (error) {
1924 			vm_map_switch_back(switch_ctx);
1925 
1926 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1927 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_SET_DYLD_INFO, 0, 0);
1928 
1929 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_SET_DYLD_INFO);
1930 			if (bootarg_execfailurereports) {
1931 				set_proc_name(imgp, p);
1932 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1933 			}
1934 			error = EINVAL;
1935 			goto badtoolate;
1936 		}
1937 	}
1938 
1939 #if CONFIG_ROSETTA
1940 	if (load_result.is_rosetta) {
1941 		// Add an fd for the executable file for Rosetta's use
1942 		int main_binary_fd;
1943 		struct fileproc *fp;
1944 
1945 		error = falloc_exec(p, imgp->ip_vfs_context, &fp, &main_binary_fd);
1946 		if (error) {
1947 			vm_map_switch_back(switch_ctx);
1948 
1949 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1950 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_MAIN_FD_ALLOC, 0, 0);
1951 
1952 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_MAIN_FD_ALLOC);
1953 			if (bootarg_execfailurereports) {
1954 				set_proc_name(imgp, p);
1955 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1956 			}
1957 			goto badtoolate;
1958 		}
1959 
1960 		error = VNOP_OPEN(imgp->ip_vp, FREAD, imgp->ip_vfs_context);
1961 		if (error) {
1962 			vm_map_switch_back(switch_ctx);
1963 
1964 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1965 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_MAIN_FD_ALLOC, 0, 0);
1966 
1967 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_MAIN_FD_ALLOC);
1968 			if (bootarg_execfailurereports) {
1969 				set_proc_name(imgp, p);
1970 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
1971 			}
1972 			goto cleanup_rosetta_fp;
1973 		}
1974 
1975 		fp->fp_glob->fg_flag = FREAD;
1976 		fp->fp_glob->fg_ops = &vnops;
1977 		fp_set_data(fp, imgp->ip_vp);
1978 
1979 		proc_fdlock(p);
1980 		procfdtbl_releasefd(p, main_binary_fd, NULL);
1981 		fp_drop(p, main_binary_fd, fp, 1);
1982 		proc_fdunlock(p);
1983 
1984 		vnode_ref(imgp->ip_vp);
1985 
1986 		// Pass the dyld load address, main binary fd, and dyld fd on the stack
1987 		uint64_t ap = thread_adjuserstack(thread, -24);
1988 
1989 		error = copyoutptr((user_addr_t)load_result.dynlinker_fd, ap, 8);
1990 		if (error) {
1991 			vm_map_switch_back(switch_ctx);
1992 
1993 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
1994 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_ROSETTA, 0, 0);
1995 
1996 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_ROSETTA);
1997 			if (bootarg_execfailurereports) {
1998 				set_proc_name(imgp, p);
1999 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
2000 			}
2001 			goto cleanup_rosetta_fp;
2002 		}
2003 
2004 		error = copyoutptr(load_result.dynlinker_mach_header, ap + 8, 8);
2005 		if (error) {
2006 			vm_map_switch_back(switch_ctx);
2007 
2008 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
2009 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_ROSETTA, 0, 0);
2010 
2011 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_ROSETTA);
2012 			if (bootarg_execfailurereports) {
2013 				set_proc_name(imgp, p);
2014 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
2015 			}
2016 			goto cleanup_rosetta_fp;
2017 		}
2018 
2019 		error = copyoutptr((user_addr_t)main_binary_fd, ap + 16, 8);
2020 		if (error) {
2021 			vm_map_switch_back(switch_ctx);
2022 
2023 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
2024 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_ROSETTA, 0, 0);
2025 
2026 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_ROSETTA);
2027 			if (bootarg_execfailurereports) {
2028 				set_proc_name(imgp, p);
2029 				exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT;
2030 			}
2031 			goto cleanup_rosetta_fp;
2032 		}
2033 
2034 cleanup_rosetta_fp:
2035 		if (error) {
2036 			fp_free(p, load_result.dynlinker_fd, load_result.dynlinker_fp);
2037 			fp_free(p, main_binary_fd, fp);
2038 			goto badtoolate;
2039 		}
2040 	}
2041 
2042 #endif
2043 
2044 	/* Avoid immediate VM faults back into kernel */
2045 	exec_prefault_data(p, imgp, &load_result);
2046 
2047 	vm_map_switch_back(switch_ctx);
2048 
2049 	/*
2050 	 * Reset signal state.
2051 	 */
2052 	execsigs(p, thread);
2053 
2054 	/*
2055 	 * need to cancel async IO requests that can be cancelled and wait for those
2056 	 * already active.  MAY BLOCK!
2057 	 */
2058 	_aio_exec( p );
2059 
2060 #if SYSV_SHM
2061 	/* FIXME: Till vmspace inherit is fixed: */
2062 	if (!vfexec && p->vm_shm) {
2063 		shmexec(p);
2064 	}
2065 #endif
2066 #if SYSV_SEM
2067 	/* Clean up the semaphores */
2068 	semexit(p);
2069 #endif
2070 
2071 	/*
2072 	 * Remember file name for accounting.
2073 	 */
2074 	p->p_acflag &= ~AFORK;
2075 
2076 	set_proc_name(imgp, p);
2077 
2078 #if CONFIG_SECLUDED_MEMORY
2079 	if (secluded_for_apps &&
2080 	    load_result.platform_binary) {
2081 		if (strncmp(p->p_name,
2082 		    "Camera",
2083 		    sizeof(p->p_name)) == 0) {
2084 			task_set_could_use_secluded_mem(task, TRUE);
2085 		} else {
2086 			task_set_could_use_secluded_mem(task, FALSE);
2087 		}
2088 		if (strncmp(p->p_name,
2089 		    "mediaserverd",
2090 		    sizeof(p->p_name)) == 0) {
2091 			task_set_could_also_use_secluded_mem(task, TRUE);
2092 		}
2093 		if (strncmp(p->p_name,
2094 		    "cameracaptured",
2095 		    sizeof(p->p_name)) == 0) {
2096 			task_set_could_also_use_secluded_mem(task, TRUE);
2097 		}
2098 	}
2099 #endif /* CONFIG_SECLUDED_MEMORY */
2100 
2101 #if __arm64__
2102 	if (load_result.legacy_footprint) {
2103 		task_set_legacy_footprint(task);
2104 	}
2105 #endif /* __arm64__ */
2106 
2107 	pal_dbg_set_task_name(task);
2108 
2109 #if DEVELOPMENT || DEBUG
2110 	/*
2111 	 * Update the pid an proc name for importance base if any
2112 	 */
2113 	task_importance_update_owner_info(task);
2114 #endif
2115 
2116 	proc_setexecutableuuid(p, &load_result.uuid[0]);
2117 
2118 #if CONFIG_DTRACE
2119 	dtrace_proc_exec(p);
2120 #endif
2121 
2122 	if (kdebug_enable) {
2123 		long args[4] = {};
2124 
2125 		uintptr_t fsid = 0, fileid = 0;
2126 		if (imgp->ip_vattr) {
2127 			uint64_t fsid64 = vnode_get_va_fsid(imgp->ip_vattr);
2128 			fsid   = (uintptr_t)fsid64;
2129 			fileid = (uintptr_t)imgp->ip_vattr->va_fileid;
2130 			// check for (unexpected) overflow and trace zero in that case
2131 			if (fsid != fsid64 || fileid != imgp->ip_vattr->va_fileid) {
2132 				fsid = fileid = 0;
2133 			}
2134 		}
2135 		KERNEL_DEBUG_CONSTANT_IST1(TRACE_DATA_EXEC, proc_getpid(p), fsid, fileid, 0,
2136 		    (uintptr_t)thread_tid(thread));
2137 
2138 		extern void kdebug_proc_name_args(struct proc *proc, long args[static 4]);
2139 		kdebug_proc_name_args(p, args);
2140 		KERNEL_DEBUG_CONSTANT_IST1(TRACE_STRING_EXEC, args[0], args[1],
2141 		    args[2], args[3], (uintptr_t)thread_tid(thread));
2142 	}
2143 
2144 
2145 	/*
2146 	 * If posix_spawned with the START_SUSPENDED flag, stop the
2147 	 * process before it runs.
2148 	 */
2149 	if (imgp->ip_px_sa != NULL) {
2150 		psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
2151 		if (psa->psa_flags & POSIX_SPAWN_START_SUSPENDED) {
2152 			proc_lock(p);
2153 			p->p_stat = SSTOP;
2154 			proc_unlock(p);
2155 			(void) task_suspend_internal(task);
2156 		}
2157 	}
2158 
2159 	/*
2160 	 * mark as execed
2161 	 */
2162 	OSBitOrAtomic(P_EXEC, &p->p_flag);
2163 	proc_resetregister(p);
2164 	if (p->p_pptr && (p->p_lflag & P_LPPWAIT)) {
2165 		proc_lock(p);
2166 		p->p_lflag &= ~P_LPPWAIT;
2167 		proc_unlock(p);
2168 		wakeup((caddr_t)p->p_pptr);
2169 	}
2170 
2171 	/*
2172 	 * Set up dext coredumps on kernel panic.
2173 	 * This requires the following:
2174 	 * - dext_panic_coredump=1 boot-arg (enabled by default on DEVELOPMENT, DEBUG and certain Seed builds)
2175 	 * - process must be a driver
2176 	 * - process must have the com.apple.private.enable-coredump-on-panic entitlement, and the
2177 	 *   entitlement has a string value.
2178 	 * - process must have the com.apple.private.enable-coredump-on-panic-seed-privacy-approved
2179 	 *   entitlement (Seed builds only).
2180 	 *
2181 	 * The core dump file name is formatted with the entitlement string value, followed by a hyphen
2182 	 * and the process PID.
2183 	 */
2184 	if (enable_dext_coredumps_on_panic &&
2185 	    (imgp->ip_flags & IMGPF_DRIVER) != 0 &&
2186 	    (userspace_coredump_name = IOVnodeGetEntitlement(imgp->ip_vp,
2187 	    (int64_t)imgp->ip_arch_offset, USERSPACE_COREDUMP_PANIC_ENTITLEMENT)) != NULL) {
2188 		size_t userspace_coredump_name_len = strlen(userspace_coredump_name);
2189 
2190 		char core_name[MACH_CORE_FILEHEADER_NAMELEN];
2191 		/* 16 - NULL char - strlen("-") - maximum of 5 digits for pid */
2192 		snprintf(core_name, MACH_CORE_FILEHEADER_NAMELEN, "%.9s-%d", userspace_coredump_name, proc_getpid(p));
2193 
2194 		kern_register_userspace_coredump(task, core_name);
2195 
2196 		/* Discard the copy of the entitlement */
2197 		kfree_data(userspace_coredump_name, userspace_coredump_name_len + 1);
2198 		userspace_coredump_name = NULL;
2199 	}
2200 
2201 	goto done;
2202 
2203 badtoolate:
2204 	/* Don't allow child process to execute any instructions */
2205 	if (!spawn) {
2206 		{
2207 			assert(exec_failure_reason != OS_REASON_NULL);
2208 			if (bootarg_execfailurereports) {
2209 				set_proc_name(imgp, current_proc());
2210 			}
2211 			psignal_with_reason(current_proc(), SIGKILL, exec_failure_reason);
2212 			exec_failure_reason = OS_REASON_NULL;
2213 
2214 			if (exec) {
2215 				/* Terminate the exec copy task */
2216 				task_terminate_internal(task);
2217 			}
2218 		}
2219 
2220 		/* We can't stop this system call at this point, so just pretend we succeeded */
2221 		error = 0;
2222 	} else {
2223 		os_reason_free(exec_failure_reason);
2224 		exec_failure_reason = OS_REASON_NULL;
2225 	}
2226 
2227 done:
2228 	if (load_result.threadstate) {
2229 		kfree_data(load_result.threadstate, load_result.threadstate_sz);
2230 		load_result.threadstate = NULL;
2231 	}
2232 
2233 bad:
2234 	/* If we hit this, we likely would have leaked an exit reason */
2235 	assert(exec_failure_reason == OS_REASON_NULL);
2236 	return error;
2237 }
2238 
2239 
2240 
2241 
2242 /*
2243  * Our image activator table; this is the table of the image types we are
2244  * capable of loading.  We list them in order of preference to ensure the
2245  * fastest image load speed.
2246  *
2247  * XXX hardcoded, for now; should use linker sets
2248  */
2249 struct execsw {
2250 	int(*const ex_imgact)(struct image_params *);
2251 	const char *ex_name;
2252 }const execsw[] = {
2253 	{ exec_mach_imgact, "Mach-o Binary" },
2254 	{ exec_fat_imgact, "Fat Binary" },
2255 	{ exec_shell_imgact, "Interpreter Script" },
2256 	{ NULL, NULL}
2257 };
2258 
2259 
2260 /*
2261  * exec_activate_image
2262  *
2263  * Description:	Iterate through the available image activators, and activate
2264  *		the image associated with the imgp structure.  We start with
2265  *		the activator for Mach-o binaries followed by that for Fat binaries
2266  *		for Interpreter scripts.
2267  *
2268  * Parameters:	struct image_params *	Image parameter block
2269  *
2270  * Returns:	0			Success
2271  *		ENOEXEC			No activator for image.
2272  *		EBADEXEC		The executable is corrupt/unknown
2273  *	execargs_alloc:EINVAL		Invalid argument
2274  *	execargs_alloc:EACCES		Permission denied
2275  *	execargs_alloc:EINTR		Interrupted function
2276  *	execargs_alloc:ENOMEM		Not enough space
2277  *	exec_save_path:EFAULT		Bad address
2278  *	exec_save_path:ENAMETOOLONG	Filename too long
2279  *	exec_check_permissions:EACCES	Permission denied
2280  *	exec_check_permissions:ENOEXEC	Executable file format error
2281  *	exec_check_permissions:ETXTBSY	Text file busy [misuse of error code]
2282  *	exec_check_permissions:???
2283  *	namei:???
2284  *	vn_rdwr:???			[anything vn_rdwr can return]
2285  *	<ex_imgact>:???			[anything an imgact can return]
2286  *	EDEADLK				Process is being terminated
2287  */
2288 static int
exec_activate_image(struct image_params * imgp)2289 exec_activate_image(struct image_params *imgp)
2290 {
2291 	struct nameidata *ndp = NULL;
2292 	const char *excpath;
2293 	int error;
2294 	int resid;
2295 	int once = 1;   /* save SGUID-ness for interpreted files */
2296 	int i;
2297 	int itercount = 0;
2298 	proc_t p = vfs_context_proc(imgp->ip_vfs_context);
2299 
2300 	/*
2301 	 * For exec, the translock needs to be taken on old proc and not
2302 	 * on new shadow proc.
2303 	 */
2304 	if (imgp->ip_flags & IMGPF_EXEC) {
2305 		p = current_proc();
2306 	}
2307 
2308 	error = execargs_alloc(imgp);
2309 	if (error) {
2310 		goto bad_notrans;
2311 	}
2312 
2313 	error = exec_save_path(imgp, imgp->ip_user_fname, imgp->ip_seg, &excpath);
2314 	if (error) {
2315 		goto bad_notrans;
2316 	}
2317 
2318 	/* Use excpath, which contains the copyin-ed exec path */
2319 	DTRACE_PROC1(exec, uintptr_t, excpath);
2320 
2321 	ndp = kalloc_type(struct nameidata, Z_WAITOK | Z_ZERO | Z_NOFAIL);
2322 
2323 	NDINIT(ndp, LOOKUP, OP_LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
2324 	    UIO_SYSSPACE, CAST_USER_ADDR_T(excpath), imgp->ip_vfs_context);
2325 
2326 again:
2327 	error = namei(ndp);
2328 	if (error) {
2329 		if (error == ERESTART) {
2330 			error = EINTR;
2331 		}
2332 		goto bad_notrans;
2333 	}
2334 	imgp->ip_ndp = ndp;     /* successful namei(); call nameidone() later */
2335 	imgp->ip_vp = ndp->ni_vp;       /* if set, need to vnode_put() at some point */
2336 
2337 	/*
2338 	 * Before we start the transition from binary A to binary B, make
2339 	 * sure another thread hasn't started exiting the process.  We grab
2340 	 * the proc lock to check p_lflag initially, and the transition
2341 	 * mechanism ensures that the value doesn't change after we release
2342 	 * the lock.
2343 	 */
2344 	proc_lock(p);
2345 	if (p->p_lflag & P_LEXIT) {
2346 		error = EDEADLK;
2347 		proc_unlock(p);
2348 		goto bad_notrans;
2349 	}
2350 	error = proc_transstart(p, 1, 0);
2351 	proc_unlock(p);
2352 	if (error) {
2353 		goto bad_notrans;
2354 	}
2355 
2356 	error = exec_check_permissions(imgp);
2357 	if (error) {
2358 		goto bad;
2359 	}
2360 
2361 	/* Copy; avoid invocation of an interpreter overwriting the original */
2362 	if (once) {
2363 		once = 0;
2364 		*imgp->ip_origvattr = *imgp->ip_vattr;
2365 	}
2366 
2367 	error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, 0,
2368 	    UIO_SYSSPACE, IO_NODELOCKED,
2369 	    vfs_context_ucred(imgp->ip_vfs_context),
2370 	    &resid, vfs_context_proc(imgp->ip_vfs_context));
2371 	if (error) {
2372 		goto bad;
2373 	}
2374 
2375 	if (resid) {
2376 		memset(imgp->ip_vdata + (PAGE_SIZE - resid), 0x0, resid);
2377 	}
2378 
2379 encapsulated_binary:
2380 	/* Limit the number of iterations we will attempt on each binary */
2381 	if (++itercount > EAI_ITERLIMIT) {
2382 		error = EBADEXEC;
2383 		goto bad;
2384 	}
2385 	error = -1;
2386 	for (i = 0; error == -1 && execsw[i].ex_imgact != NULL; i++) {
2387 		error = (*execsw[i].ex_imgact)(imgp);
2388 
2389 		switch (error) {
2390 		/* case -1: not claimed: continue */
2391 		case -2:                /* Encapsulated binary, imgp->ip_XXX set for next iteration */
2392 			goto encapsulated_binary;
2393 
2394 		case -3:                /* Interpreter */
2395 #if CONFIG_MACF
2396 			/*
2397 			 * Copy the script label for later use. Note that
2398 			 * the label can be different when the script is
2399 			 * actually read by the interpreter.
2400 			 */
2401 			if (imgp->ip_scriptlabelp) {
2402 				mac_vnode_label_free(imgp->ip_scriptlabelp);
2403 				imgp->ip_scriptlabelp = NULL;
2404 			}
2405 			imgp->ip_scriptlabelp = mac_vnode_label_alloc(NULL);
2406 			if (imgp->ip_scriptlabelp == NULL) {
2407 				error = ENOMEM;
2408 				break;
2409 			}
2410 			mac_vnode_label_copy(mac_vnode_label(imgp->ip_vp),
2411 			    imgp->ip_scriptlabelp);
2412 
2413 			/*
2414 			 * Take a ref of the script vnode for later use.
2415 			 */
2416 			if (imgp->ip_scriptvp) {
2417 				vnode_put(imgp->ip_scriptvp);
2418 				imgp->ip_scriptvp = NULLVP;
2419 			}
2420 			if (vnode_getwithref(imgp->ip_vp) == 0) {
2421 				imgp->ip_scriptvp = imgp->ip_vp;
2422 			}
2423 #endif
2424 
2425 			nameidone(ndp);
2426 
2427 			vnode_put(imgp->ip_vp);
2428 			imgp->ip_vp = NULL;     /* already put */
2429 			imgp->ip_ndp = NULL; /* already nameidone */
2430 
2431 			/* Use excpath, which exec_shell_imgact reset to the interpreter */
2432 			NDINIT(ndp, LOOKUP, OP_LOOKUP, FOLLOW | LOCKLEAF,
2433 			    UIO_SYSSPACE, CAST_USER_ADDR_T(excpath), imgp->ip_vfs_context);
2434 
2435 			proc_transend(p, 0);
2436 			goto again;
2437 
2438 		default:
2439 			break;
2440 		}
2441 	}
2442 
2443 	if (error == -1) {
2444 		error = ENOEXEC;
2445 	} else if (error == 0) {
2446 		if (imgp->ip_flags & IMGPF_INTERPRET && ndp->ni_vp) {
2447 			AUDIT_ARG(vnpath, ndp->ni_vp, ARG_VNODE2);
2448 		}
2449 
2450 		/*
2451 		 * Call out to allow 3rd party notification of exec.
2452 		 * Ignore result of kauth_authorize_fileop call.
2453 		 */
2454 		if (kauth_authorize_fileop_has_listeners()) {
2455 			kauth_authorize_fileop(vfs_context_ucred(imgp->ip_vfs_context),
2456 			    KAUTH_FILEOP_EXEC,
2457 			    (uintptr_t)ndp->ni_vp, 0);
2458 		}
2459 	}
2460 bad:
2461 	proc_transend(p, 0);
2462 
2463 bad_notrans:
2464 	if (imgp->ip_strings) {
2465 		execargs_free(imgp);
2466 	}
2467 	if (imgp->ip_ndp) {
2468 		nameidone(imgp->ip_ndp);
2469 	}
2470 	kfree_type(struct nameidata, ndp);
2471 
2472 	return error;
2473 }
2474 
2475 
2476 /*
2477  * exec_validate_spawnattr_policy
2478  *
2479  * Description: Validates the entitlements required to set the apptype.
2480  *
2481  * Parameters:  int psa_apptype         posix spawn attribute apptype
2482  *
2483  * Returns:     0                       Success
2484  *              EPERM                   Failure
2485  */
2486 static errno_t
exec_validate_spawnattr_policy(int psa_apptype)2487 exec_validate_spawnattr_policy(int psa_apptype)
2488 {
2489 	if ((psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK) != 0) {
2490 		int proctype = psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK;
2491 		if (proctype == POSIX_SPAWN_PROC_TYPE_DRIVER) {
2492 			if (!IOCurrentTaskHasEntitlement(POSIX_SPAWN_ENTITLEMENT_DRIVER)) {
2493 				return EPERM;
2494 			}
2495 		}
2496 	}
2497 
2498 	return 0;
2499 }
2500 
2501 /*
2502  * exec_handle_spawnattr_policy
2503  *
2504  * Description: Decode and apply the posix_spawn apptype, qos clamp, and watchport ports to the task.
2505  *
2506  * Parameters:  proc_t p                process to apply attributes to
2507  *              int psa_apptype         posix spawn attribute apptype
2508  *
2509  * Returns:     0                       Success
2510  */
2511 static errno_t
exec_handle_spawnattr_policy(proc_t p,thread_t thread,int psa_apptype,uint64_t psa_qos_clamp,task_role_t psa_darwin_role,struct exec_port_actions * port_actions)2512 exec_handle_spawnattr_policy(proc_t p, thread_t thread, int psa_apptype, uint64_t psa_qos_clamp,
2513     task_role_t psa_darwin_role, struct exec_port_actions *port_actions)
2514 {
2515 	int apptype     = TASK_APPTYPE_NONE;
2516 	int qos_clamp   = THREAD_QOS_UNSPECIFIED;
2517 	task_role_t role = TASK_UNSPECIFIED;
2518 
2519 	if ((psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK) != 0) {
2520 		int proctype = psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK;
2521 
2522 		switch (proctype) {
2523 		case POSIX_SPAWN_PROC_TYPE_DAEMON_INTERACTIVE:
2524 			apptype = TASK_APPTYPE_DAEMON_INTERACTIVE;
2525 			break;
2526 		case POSIX_SPAWN_PROC_TYPE_DAEMON_STANDARD:
2527 			apptype = TASK_APPTYPE_DAEMON_STANDARD;
2528 			break;
2529 		case POSIX_SPAWN_PROC_TYPE_DAEMON_ADAPTIVE:
2530 			apptype = TASK_APPTYPE_DAEMON_ADAPTIVE;
2531 			break;
2532 		case POSIX_SPAWN_PROC_TYPE_DAEMON_BACKGROUND:
2533 			apptype = TASK_APPTYPE_DAEMON_BACKGROUND;
2534 			break;
2535 		case POSIX_SPAWN_PROC_TYPE_APP_DEFAULT:
2536 			apptype = TASK_APPTYPE_APP_DEFAULT;
2537 			break;
2538 		case POSIX_SPAWN_PROC_TYPE_DRIVER:
2539 			apptype = TASK_APPTYPE_DRIVER;
2540 			break;
2541 		default:
2542 			apptype = TASK_APPTYPE_NONE;
2543 			/* TODO: Should an invalid value here fail the spawn? */
2544 			break;
2545 		}
2546 	}
2547 
2548 	if (psa_qos_clamp != POSIX_SPAWN_PROC_CLAMP_NONE) {
2549 		switch (psa_qos_clamp) {
2550 		case POSIX_SPAWN_PROC_CLAMP_UTILITY:
2551 			qos_clamp = THREAD_QOS_UTILITY;
2552 			break;
2553 		case POSIX_SPAWN_PROC_CLAMP_BACKGROUND:
2554 			qos_clamp = THREAD_QOS_BACKGROUND;
2555 			break;
2556 		case POSIX_SPAWN_PROC_CLAMP_MAINTENANCE:
2557 			qos_clamp = THREAD_QOS_MAINTENANCE;
2558 			break;
2559 		default:
2560 			qos_clamp = THREAD_QOS_UNSPECIFIED;
2561 			/* TODO: Should an invalid value here fail the spawn? */
2562 			break;
2563 		}
2564 	}
2565 
2566 	if (psa_darwin_role != PRIO_DARWIN_ROLE_DEFAULT) {
2567 		proc_darwin_role_to_task_role(psa_darwin_role, &role);
2568 	}
2569 
2570 	if (apptype != TASK_APPTYPE_NONE ||
2571 	    qos_clamp != THREAD_QOS_UNSPECIFIED ||
2572 	    role != TASK_UNSPECIFIED ||
2573 	    port_actions->portwatch_count) {
2574 		proc_set_task_spawnpolicy(proc_task(p), thread, apptype, qos_clamp, role,
2575 		    port_actions->portwatch_array, port_actions->portwatch_count);
2576 	}
2577 
2578 	if (port_actions->registered_count) {
2579 		if (_kernelrpc_mach_ports_register3(proc_task(p),
2580 		    port_actions->registered_array[0],
2581 		    port_actions->registered_array[1],
2582 		    port_actions->registered_array[2])) {
2583 			return EINVAL;
2584 		}
2585 		/* mach_ports_register() consumed the array */
2586 		bzero(port_actions->registered_array,
2587 		    sizeof(port_actions->registered_array));
2588 		port_actions->registered_count = 0;
2589 	}
2590 
2591 	return 0;
2592 }
2593 
2594 static void
exec_port_actions_destroy(struct exec_port_actions * port_actions)2595 exec_port_actions_destroy(struct exec_port_actions *port_actions)
2596 {
2597 	if (port_actions->excport_array) {
2598 		for (uint32_t i = 0; i < port_actions->exception_port_count; i++) {
2599 			ipc_port_t port = NULL;
2600 			if ((port = port_actions->excport_array[i].port) != NULL) {
2601 				ipc_port_release_send(port);
2602 			}
2603 		}
2604 		kfree_type(struct exception_port_action_t, port_actions->exception_port_count,
2605 		    port_actions->excport_array);
2606 	}
2607 
2608 	if (port_actions->portwatch_array) {
2609 		for (uint32_t i = 0; i < port_actions->portwatch_count; i++) {
2610 			ipc_port_t port = NULL;
2611 			if ((port = port_actions->portwatch_array[i]) != NULL) {
2612 				ipc_port_release_send(port);
2613 			}
2614 		}
2615 		kfree_type(ipc_port_t, port_actions->portwatch_count,
2616 		    port_actions->portwatch_array);
2617 	}
2618 
2619 	for (uint32_t i = 0; i < port_actions->registered_count; i++) {
2620 		ipc_port_t port = NULL;
2621 		if ((port = port_actions->registered_array[i]) != NULL) {
2622 			ipc_port_release_send(port);
2623 		}
2624 	}
2625 }
2626 
2627 /*
2628  * exec_handle_port_actions
2629  *
2630  * Description:	Go through the _posix_port_actions_t contents,
2631  *              calling task_set_special_port, task_set_exception_ports
2632  *              and/or audit_session_spawnjoin for the current task.
2633  *
2634  * Parameters:	struct image_params *	Image parameter block
2635  *
2636  * Returns:	0			Success
2637  *              EINVAL			Failure
2638  *              ENOTSUP			Illegal posix_spawn attr flag was set
2639  */
2640 static errno_t
exec_handle_port_actions(struct image_params * imgp,struct exec_port_actions * actions)2641 exec_handle_port_actions(struct image_params *imgp,
2642     struct exec_port_actions *actions)
2643 {
2644 	_posix_spawn_port_actions_t pacts = imgp->ip_px_spa;
2645 #if CONFIG_AUDIT
2646 	proc_t p = vfs_context_proc(imgp->ip_vfs_context);
2647 #endif
2648 	_ps_port_action_t *act = NULL;
2649 	task_t task = get_threadtask(imgp->ip_new_thread);
2650 	ipc_port_t port = NULL;
2651 	errno_t ret = 0;
2652 	int i = 0, portwatch_i = 0, registered_i = 0, excport_i = 0;
2653 	kern_return_t kr;
2654 	boolean_t task_has_watchport_boost = task_has_watchports(current_task());
2655 	boolean_t in_exec = (imgp->ip_flags & IMGPF_EXEC);
2656 	int ptrauth_task_port_count = 0;
2657 
2658 	for (i = 0; i < pacts->pspa_count; i++) {
2659 		act = &pacts->pspa_actions[i];
2660 
2661 		switch (act->port_type) {
2662 		case PSPA_SPECIAL:
2663 #if CONFIG_AUDIT
2664 		case PSPA_AU_SESSION:
2665 #endif
2666 			break;
2667 		case PSPA_EXCEPTION:
2668 			if (++actions->exception_port_count > TASK_MAX_EXCEPTION_PORT_COUNT) {
2669 				ret = EINVAL;
2670 				goto done;
2671 			}
2672 			break;
2673 		case PSPA_IMP_WATCHPORTS:
2674 			if (++actions->portwatch_count > TASK_MAX_WATCHPORT_COUNT) {
2675 				ret = EINVAL;
2676 				goto done;
2677 			}
2678 			break;
2679 		case PSPA_REGISTERED_PORTS:
2680 			if (++actions->registered_count > TASK_PORT_REGISTER_MAX) {
2681 				ret = EINVAL;
2682 				goto done;
2683 			}
2684 			break;
2685 		case PSPA_PTRAUTH_TASK_PORT:
2686 			if (++ptrauth_task_port_count > 1) {
2687 				ret = EINVAL;
2688 				goto done;
2689 			}
2690 			break;
2691 		default:
2692 			ret = EINVAL;
2693 			goto done;
2694 		}
2695 	}
2696 
2697 	if (actions->exception_port_count) {
2698 		actions->excport_array = kalloc_type(struct exception_port_action_t,
2699 		    actions->exception_port_count, Z_WAITOK | Z_ZERO);
2700 
2701 		if (actions->excport_array == NULL) {
2702 			ret = ENOMEM;
2703 			goto done;
2704 		}
2705 	}
2706 	if (actions->portwatch_count) {
2707 		if (in_exec && task_has_watchport_boost) {
2708 			ret = EINVAL;
2709 			goto done;
2710 		}
2711 		actions->portwatch_array = kalloc_type(ipc_port_t,
2712 		    actions->portwatch_count, Z_WAITOK | Z_ZERO);
2713 		if (actions->portwatch_array == NULL) {
2714 			ret = ENOMEM;
2715 			goto done;
2716 		}
2717 	}
2718 
2719 	for (i = 0; i < pacts->pspa_count; i++) {
2720 		act = &pacts->pspa_actions[i];
2721 
2722 		if (MACH_PORT_VALID(act->new_port)) {
2723 			kr = ipc_typed_port_copyin_send(get_task_ipcspace(current_task()),
2724 			    act->new_port, IKOT_UNKNOWN, &port);
2725 
2726 			if (kr != KERN_SUCCESS) {
2727 				ret = EINVAL;
2728 				goto done;
2729 			}
2730 		} else {
2731 			/* it's NULL or DEAD */
2732 			port = CAST_MACH_NAME_TO_PORT(act->new_port);
2733 		}
2734 
2735 		switch (act->port_type) {
2736 		case PSPA_SPECIAL:
2737 			kr = task_set_special_port(task, act->which, port);
2738 
2739 			if (kr != KERN_SUCCESS) {
2740 				ret = EINVAL;
2741 			}
2742 			break;
2743 
2744 #if CONFIG_AUDIT
2745 		case PSPA_AU_SESSION:
2746 			ret = audit_session_spawnjoin(p, port);
2747 			if (ret) {
2748 				/* audit_session_spawnjoin() has already dropped the reference in case of error. */
2749 				goto done;
2750 			}
2751 
2752 			break;
2753 #endif
2754 		case PSPA_EXCEPTION:
2755 			assert(excport_i < actions->exception_port_count);
2756 			/* hold on to this till end of spawn */
2757 			actions->excport_array[excport_i].port_action = act;
2758 			actions->excport_array[excport_i].port = port;
2759 			excport_i++;
2760 			break;
2761 		case PSPA_IMP_WATCHPORTS:
2762 			assert(portwatch_i < actions->portwatch_count);
2763 			/* hold on to this till end of spawn */
2764 			actions->portwatch_array[portwatch_i++] = port;
2765 			break;
2766 		case PSPA_REGISTERED_PORTS:
2767 			assert(registered_i < actions->registered_count);
2768 			/* hold on to this till end of spawn */
2769 			actions->registered_array[registered_i++] = port;
2770 			break;
2771 
2772 		case PSPA_PTRAUTH_TASK_PORT:
2773 #if (DEVELOPMENT || DEBUG)
2774 #if defined(HAS_APPLE_PAC)
2775 			{
2776 				task_t ptr_auth_task = convert_port_to_task(port);
2777 
2778 				if (ptr_auth_task == TASK_NULL) {
2779 					ret = EINVAL;
2780 					break;
2781 				}
2782 
2783 				imgp->ip_inherited_shared_region_id =
2784 				    task_get_vm_shared_region_id_and_jop_pid(ptr_auth_task,
2785 				    &imgp->ip_inherited_jop_pid);
2786 
2787 				/* Deallocate task ref returned by convert_port_to_task */
2788 				task_deallocate(ptr_auth_task);
2789 			}
2790 #endif /* HAS_APPLE_PAC */
2791 #endif /* (DEVELOPMENT || DEBUG) */
2792 
2793 			/* consume the port right in case of success */
2794 			ipc_port_release_send(port);
2795 			break;
2796 		default:
2797 			ret = EINVAL;
2798 			break;
2799 		}
2800 
2801 		if (ret) {
2802 			/* action failed, so release port resources */
2803 			ipc_port_release_send(port);
2804 			break;
2805 		}
2806 	}
2807 
2808 done:
2809 	if (0 != ret) {
2810 		DTRACE_PROC1(spawn__port__failure, mach_port_name_t, act->new_port);
2811 	}
2812 	return ret;
2813 }
2814 
2815 
2816 /*
2817  * exec_handle_exception_port_actions
2818  *
2819  * Description:	Go through the saved exception ports in exec_port_actions,
2820  *              calling task_set_exception_ports for the current Task.
2821  *              This must happen after image activation, and after exec_resettextvp()
2822  *				because task_set_exception_ports checks the `TF_PLATFORM` bit and entitlements.
2823  *
2824  * Parameters:	struct image_params *		Image parameter block
2825  *                              struct exec_port_actions *  Saved Port Actions
2826  *
2827  * Returns:	0			Success
2828  *              EINVAL			task_set_exception_ports failed
2829  */
2830 static errno_t
exec_handle_exception_port_actions(const struct image_params * imgp,const struct exec_port_actions * actions)2831 exec_handle_exception_port_actions(const struct image_params *imgp,
2832     const struct exec_port_actions *actions)
2833 {
2834 	task_t task = get_threadtask(imgp->ip_new_thread);
2835 
2836 	for (int i = 0; i < actions->exception_port_count; i++) {
2837 		ipc_port_t port = actions->excport_array[i].port;
2838 		_ps_port_action_t *act = actions->excport_array[i].port_action;
2839 		assert(act != NULL);
2840 		kern_return_t kr = task_set_exception_ports(task, act->mask, port,
2841 		    act->behavior, act->flavor);
2842 		if (kr != KERN_SUCCESS) {
2843 			DTRACE_PROC1(spawn__exception__port__failure, mach_port_name_t, act->new_port);
2844 			return EINVAL;
2845 		}
2846 		actions->excport_array[i].port = NULL;
2847 	}
2848 
2849 	return 0;
2850 }
2851 
2852 
2853 /*
2854  * exec_handle_file_actions
2855  *
2856  * Description:	Go through the _posix_file_actions_t contents applying the
2857  *		open, close, and dup2 operations to the open file table for
2858  *		the current process.
2859  *
2860  * Parameters:	struct image_params *	Image parameter block
2861  *
2862  * Returns:	0			Success
2863  *		???
2864  *
2865  * Note:	Actions are applied in the order specified, with the credential
2866  *		of the parent process.  This is done to permit the parent
2867  *		process to utilize POSIX_SPAWN_RESETIDS to drop privilege in
2868  *		the child following operations the child may in fact not be
2869  *		normally permitted to perform.
2870  */
2871 static int
exec_handle_file_actions(struct image_params * imgp,short psa_flags)2872 exec_handle_file_actions(struct image_params *imgp, short psa_flags)
2873 {
2874 	int error = 0;
2875 	int action;
2876 	proc_t p = vfs_context_proc(imgp->ip_vfs_context);
2877 	kauth_cred_t p_cred = vfs_context_ucred(imgp->ip_vfs_context);
2878 	_posix_spawn_file_actions_t px_sfap = imgp->ip_px_sfa;
2879 	int ival[2];            /* dummy retval for system calls) */
2880 #if CONFIG_AUDIT
2881 	struct uthread *uthread = current_uthread();
2882 #endif
2883 
2884 	for (action = 0; action < px_sfap->psfa_act_count; action++) {
2885 		_psfa_action_t *psfa = &px_sfap->psfa_act_acts[action];
2886 
2887 		switch (psfa->psfaa_type) {
2888 		case PSFA_OPEN: {
2889 			/*
2890 			 * Open is different, in that it requires the use of
2891 			 * a path argument, which is normally copied in from
2892 			 * user space; because of this, we have to support an
2893 			 * open from kernel space that passes an address space
2894 			 * context of UIO_SYSSPACE, and casts the address
2895 			 * argument to a user_addr_t.
2896 			 */
2897 			struct vnode_attr *vap;
2898 			struct nameidata *ndp;
2899 			int mode = psfa->psfaa_openargs.psfao_mode;
2900 			int origfd;
2901 			struct {
2902 				struct vnode_attr va;
2903 				struct nameidata nd;
2904 			} *__open_data;
2905 
2906 			__open_data = kalloc_type(typeof(*__open_data), Z_WAITOK | Z_ZERO);
2907 			if (__open_data == NULL) {
2908 				error = ENOMEM;
2909 				break;
2910 			}
2911 
2912 			vap = &__open_data->va;
2913 			ndp = &__open_data->nd;
2914 
2915 			VATTR_INIT(vap);
2916 			/* Mask off all but regular access permissions */
2917 			mode = ((mode & ~p->p_fd.fd_cmask) & ALLPERMS) & ~S_ISTXT;
2918 			VATTR_SET(vap, va_mode, mode & ACCESSPERMS);
2919 
2920 			AUDIT_SUBCALL_ENTER(OPEN, p, uthread);
2921 
2922 			NDINIT(ndp, LOOKUP, OP_OPEN, FOLLOW | AUDITVNPATH1, UIO_SYSSPACE,
2923 			    CAST_USER_ADDR_T(psfa->psfaa_openargs.psfao_path),
2924 			    imgp->ip_vfs_context);
2925 
2926 			error = open1(imgp->ip_vfs_context, ndp,
2927 			    psfa->psfaa_openargs.psfao_oflag,
2928 			    vap, NULL, NULL, &origfd, AUTH_OPEN_NOAUTHFD);
2929 
2930 			kfree_type(typeof(*__open_data), __open_data);
2931 
2932 			AUDIT_SUBCALL_EXIT(uthread, error);
2933 
2934 			/*
2935 			 * If there's an error, or we get the right fd by
2936 			 * accident, then drop out here.  This is easier than
2937 			 * reworking all the open code to preallocate fd
2938 			 * slots, and internally taking one as an argument.
2939 			 */
2940 			if (error || origfd == psfa->psfaa_filedes) {
2941 				break;
2942 			}
2943 
2944 			/*
2945 			 * If we didn't fall out from an error, we ended up
2946 			 * with the wrong fd; so now we've got to try to dup2
2947 			 * it to the right one.
2948 			 */
2949 			AUDIT_SUBCALL_ENTER(DUP2, p, uthread);
2950 			error = dup2(p, p_cred, origfd, psfa->psfaa_filedes, ival);
2951 			AUDIT_SUBCALL_EXIT(uthread, error);
2952 			if (error) {
2953 				break;
2954 			}
2955 
2956 			/*
2957 			 * Finally, close the original fd.
2958 			 */
2959 			AUDIT_SUBCALL_ENTER(CLOSE, p, uthread);
2960 			error = close_nocancel(p, p_cred, origfd);
2961 			AUDIT_SUBCALL_EXIT(uthread, error);
2962 		}
2963 		break;
2964 
2965 		case PSFA_DUP2: {
2966 			AUDIT_SUBCALL_ENTER(DUP2, p, uthread);
2967 			error = dup2(p, p_cred, psfa->psfaa_filedes,
2968 			    psfa->psfaa_dup2args.psfad_newfiledes, ival);
2969 			AUDIT_SUBCALL_EXIT(uthread, error);
2970 		}
2971 		break;
2972 
2973 		case PSFA_FILEPORT_DUP2: {
2974 			ipc_port_t port;
2975 			kern_return_t kr;
2976 			int origfd;
2977 
2978 			if (!MACH_PORT_VALID(psfa->psfaa_fileport)) {
2979 				error = EINVAL;
2980 				break;
2981 			}
2982 
2983 			kr = ipc_typed_port_copyin_send(get_task_ipcspace(current_task()),
2984 			    psfa->psfaa_fileport, IKOT_FILEPORT, &port);
2985 
2986 			if (kr != KERN_SUCCESS) {
2987 				error = EINVAL;
2988 				break;
2989 			}
2990 
2991 			error = fileport_makefd(p, port, 0, &origfd);
2992 
2993 			if (IPC_PORT_NULL != port) {
2994 				ipc_typed_port_release_send(port, IKOT_FILEPORT);
2995 			}
2996 
2997 			if (error || origfd == psfa->psfaa_dup2args.psfad_newfiledes) {
2998 				break;
2999 			}
3000 
3001 			AUDIT_SUBCALL_ENTER(DUP2, p, uthread);
3002 			error = dup2(p, p_cred, origfd,
3003 			    psfa->psfaa_dup2args.psfad_newfiledes, ival);
3004 			AUDIT_SUBCALL_EXIT(uthread, error);
3005 			if (error) {
3006 				break;
3007 			}
3008 
3009 			AUDIT_SUBCALL_ENTER(CLOSE, p, uthread);
3010 			error = close_nocancel(p, p_cred, origfd);
3011 			AUDIT_SUBCALL_EXIT(uthread, error);
3012 		}
3013 		break;
3014 
3015 		case PSFA_CLOSE: {
3016 			AUDIT_SUBCALL_ENTER(CLOSE, p, uthread);
3017 			error = close_nocancel(p, p_cred, psfa->psfaa_filedes);
3018 			AUDIT_SUBCALL_EXIT(uthread, error);
3019 		}
3020 		break;
3021 
3022 		case PSFA_INHERIT: {
3023 			struct fileproc *fp;
3024 
3025 			/*
3026 			 * Check to see if the descriptor exists, and
3027 			 * ensure it's -not- marked as close-on-exec.
3028 			 *
3029 			 * Attempting to "inherit" a guarded fd will
3030 			 * result in a error.
3031 			 */
3032 
3033 			proc_fdlock(p);
3034 			if ((fp = fp_get_noref_locked(p, psfa->psfaa_filedes)) == NULL) {
3035 				error = EBADF;
3036 			} else if (fp->fp_guard_attrs) {
3037 				error = fp_guard_exception(p, psfa->psfaa_filedes,
3038 				    fp, kGUARD_EXC_NOCLOEXEC);
3039 			} else {
3040 				fp->fp_flags &= ~FP_CLOEXEC;
3041 				error = 0;
3042 			}
3043 			proc_fdunlock(p);
3044 		}
3045 		break;
3046 
3047 		case PSFA_CHDIR: {
3048 			/*
3049 			 * Chdir is different, in that it requires the use of
3050 			 * a path argument, which is normally copied in from
3051 			 * user space; because of this, we have to support a
3052 			 * chdir from kernel space that passes an address space
3053 			 * context of UIO_SYSSPACE, and casts the address
3054 			 * argument to a user_addr_t.
3055 			 */
3056 			struct nameidata *nd;
3057 			nd = kalloc_type(struct nameidata,
3058 			    Z_WAITOK | Z_ZERO | Z_NOFAIL);
3059 
3060 			AUDIT_SUBCALL_ENTER(CHDIR, p, uthread);
3061 			NDINIT(nd, LOOKUP, OP_CHDIR, FOLLOW | AUDITVNPATH1, UIO_SYSSPACE,
3062 			    CAST_USER_ADDR_T(psfa->psfaa_chdirargs.psfac_path),
3063 			    imgp->ip_vfs_context);
3064 
3065 			error = chdir_internal(p, imgp->ip_vfs_context, nd, 0);
3066 			kfree_type(struct nameidata, nd);
3067 			AUDIT_SUBCALL_EXIT(uthread, error);
3068 		}
3069 		break;
3070 
3071 		case PSFA_FCHDIR: {
3072 			AUDIT_SUBCALL_ENTER(FCHDIR, p, uthread);
3073 			error = fchdir(p, imgp->ip_vfs_context,
3074 			    psfa->psfaa_filedes, false);
3075 			AUDIT_SUBCALL_EXIT(uthread, error);
3076 		}
3077 		break;
3078 
3079 		default:
3080 			error = EINVAL;
3081 			break;
3082 		}
3083 
3084 		/* All file actions failures are considered fatal, per POSIX */
3085 
3086 		if (error) {
3087 			if (PSFA_OPEN == psfa->psfaa_type) {
3088 				DTRACE_PROC1(spawn__open__failure, uintptr_t,
3089 				    psfa->psfaa_openargs.psfao_path);
3090 			} else {
3091 				DTRACE_PROC1(spawn__fd__failure, int, psfa->psfaa_filedes);
3092 			}
3093 			break;
3094 		}
3095 	}
3096 
3097 	if (error != 0 || (psa_flags & POSIX_SPAWN_CLOEXEC_DEFAULT) == 0) {
3098 		return error;
3099 	}
3100 
3101 	/*
3102 	 * If POSIX_SPAWN_CLOEXEC_DEFAULT is set, behave (during
3103 	 * this spawn only) as if "close on exec" is the default
3104 	 * disposition of all pre-existing file descriptors.  In this case,
3105 	 * the list of file descriptors mentioned in the file actions
3106 	 * are the only ones that can be inherited, so mark them now.
3107 	 *
3108 	 * The actual closing part comes later, in fdt_exec().
3109 	 */
3110 	proc_fdlock(p);
3111 	for (action = 0; action < px_sfap->psfa_act_count; action++) {
3112 		_psfa_action_t *psfa = &px_sfap->psfa_act_acts[action];
3113 		int fd = psfa->psfaa_filedes;
3114 
3115 		switch (psfa->psfaa_type) {
3116 		case PSFA_DUP2:
3117 		case PSFA_FILEPORT_DUP2:
3118 			fd = psfa->psfaa_dup2args.psfad_newfiledes;
3119 			OS_FALLTHROUGH;
3120 		case PSFA_OPEN:
3121 		case PSFA_INHERIT:
3122 			*fdflags(p, fd) |= UF_INHERIT;
3123 			break;
3124 
3125 		case PSFA_CLOSE:
3126 		case PSFA_CHDIR:
3127 		case PSFA_FCHDIR:
3128 			/*
3129 			 * Although PSFA_FCHDIR does have a file descriptor, it is not
3130 			 * *creating* one, thus we do not automatically mark it for
3131 			 * inheritance under POSIX_SPAWN_CLOEXEC_DEFAULT. A client that
3132 			 * wishes it to be inherited should use the PSFA_INHERIT action
3133 			 * explicitly.
3134 			 */
3135 			break;
3136 		}
3137 	}
3138 	proc_fdunlock(p);
3139 
3140 	return 0;
3141 }
3142 
3143 #if CONFIG_MACF
3144 /*
3145  * Check that the extension's data is within the bounds of the
3146  * allocation storing all extensions' data
3147  */
3148 static inline errno_t
exec_spawnattr_validate_policyext_data(const struct ip_px_smpx_s * px_s,const _ps_mac_policy_extension_t * ext)3149 exec_spawnattr_validate_policyext_data(const struct ip_px_smpx_s *px_s,
3150     const _ps_mac_policy_extension_t *ext)
3151 {
3152 	uint64_t dataend;
3153 
3154 	if (__improbable(os_add_overflow(ext->dataoff, ext->datalen, &dataend))) {
3155 		return EOVERFLOW;
3156 	}
3157 	if (__improbable(dataend > px_s->datalen)) {
3158 		return EINVAL;
3159 	}
3160 
3161 	return 0;
3162 }
3163 
3164 /*
3165  * exec_spawnattr_getmacpolicyinfo
3166  */
3167 void *
exec_spawnattr_getmacpolicyinfo(const void * macextensions,const char * policyname,size_t * lenp)3168 exec_spawnattr_getmacpolicyinfo(const void *macextensions, const char *policyname, size_t *lenp)
3169 {
3170 	const struct ip_px_smpx_s *px_s = macextensions;
3171 	const struct _posix_spawn_mac_policy_extensions *psmx = NULL;
3172 	int i;
3173 
3174 	if (px_s == NULL) {
3175 		return NULL;
3176 	}
3177 
3178 	psmx = px_s->array;
3179 	if (psmx == NULL) {
3180 		return NULL;
3181 	}
3182 
3183 	for (i = 0; i < psmx->psmx_count; i++) {
3184 		const _ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[i];
3185 		if (strncmp(extension->policyname, policyname, sizeof(extension->policyname)) == 0) {
3186 			if (__improbable(exec_spawnattr_validate_policyext_data(px_s, extension))) {
3187 				panic("invalid mac policy extension data");
3188 			}
3189 			if (lenp != NULL) {
3190 				*lenp = (size_t)extension->datalen;
3191 			}
3192 			return (void *)((uintptr_t)px_s->data + extension->dataoff);
3193 		}
3194 	}
3195 
3196 	if (lenp != NULL) {
3197 		*lenp = 0;
3198 	}
3199 	return NULL;
3200 }
3201 
3202 static int
spawn_copyin_macpolicyinfo(const struct user__posix_spawn_args_desc * px_args,struct ip_px_smpx_s * pxsp)3203 spawn_copyin_macpolicyinfo(const struct user__posix_spawn_args_desc *px_args,
3204     struct ip_px_smpx_s *pxsp)
3205 {
3206 	_posix_spawn_mac_policy_extensions_t psmx = NULL;
3207 	uint8_t *data = NULL;
3208 	uint64_t datalen = 0;
3209 	uint64_t dataoff = 0;
3210 	int error = 0;
3211 
3212 	bzero(pxsp, sizeof(*pxsp));
3213 
3214 	if (px_args->mac_extensions_size < PS_MAC_EXTENSIONS_SIZE(1) ||
3215 	    px_args->mac_extensions_size > PAGE_SIZE) {
3216 		error = EINVAL;
3217 		goto bad;
3218 	}
3219 
3220 	psmx = kalloc_data(px_args->mac_extensions_size, Z_WAITOK);
3221 	if (psmx == NULL) {
3222 		error = ENOMEM;
3223 		goto bad;
3224 	}
3225 
3226 	error = copyin(px_args->mac_extensions, psmx, px_args->mac_extensions_size);
3227 	if (error) {
3228 		goto bad;
3229 	}
3230 
3231 	size_t extsize = PS_MAC_EXTENSIONS_SIZE(psmx->psmx_count);
3232 	if (extsize == 0 || extsize > px_args->mac_extensions_size) {
3233 		error = EINVAL;
3234 		goto bad;
3235 	}
3236 
3237 	for (int i = 0; i < psmx->psmx_count; i++) {
3238 		_ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[i];
3239 		if (extension->datalen == 0 || extension->datalen > PAGE_SIZE) {
3240 			error = EINVAL;
3241 			goto bad;
3242 		}
3243 		if (__improbable(os_add_overflow(datalen, extension->datalen, &datalen))) {
3244 			error = ENOMEM;
3245 			goto bad;
3246 		}
3247 	}
3248 
3249 	data = kalloc_data((vm_size_t)datalen, Z_WAITOK);
3250 	if (data == NULL) {
3251 		error = ENOMEM;
3252 		goto bad;
3253 	}
3254 
3255 	for (int i = 0; i < psmx->psmx_count; i++) {
3256 		_ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[i];
3257 
3258 #if !__LP64__
3259 		if (extension->data > UINT32_MAX) {
3260 			goto bad;
3261 		}
3262 #endif
3263 		error = copyin((user_addr_t)extension->data, &data[dataoff], (size_t)extension->datalen);
3264 		if (error) {
3265 			error = ENOMEM;
3266 			goto bad;
3267 		}
3268 		extension->dataoff = dataoff;
3269 		dataoff += extension->datalen;
3270 	}
3271 
3272 	pxsp->array = psmx;
3273 	pxsp->data = data;
3274 	pxsp->datalen = datalen;
3275 	return 0;
3276 
3277 bad:
3278 	kfree_data(psmx, px_args->mac_extensions_size);
3279 	kfree_data(data, (vm_size_t)datalen);
3280 	return error;
3281 }
3282 #endif /* CONFIG_MACF */
3283 
3284 #if CONFIG_COALITIONS
3285 static inline void
spawn_coalitions_release_all(coalition_t coal[COALITION_NUM_TYPES])3286 spawn_coalitions_release_all(coalition_t coal[COALITION_NUM_TYPES])
3287 {
3288 	for (int c = 0; c < COALITION_NUM_TYPES; c++) {
3289 		if (coal[c]) {
3290 			coalition_remove_active(coal[c]);
3291 			coalition_release(coal[c]);
3292 		}
3293 	}
3294 }
3295 #endif
3296 
3297 #if CONFIG_PERSONAS
3298 static int
spawn_validate_persona(struct _posix_spawn_persona_info * px_persona)3299 spawn_validate_persona(struct _posix_spawn_persona_info *px_persona)
3300 {
3301 	int error = 0;
3302 	struct persona *persona = NULL;
3303 	kauth_cred_t mycred = kauth_cred_get();
3304 
3305 	if (!IOCurrentTaskHasEntitlement( PERSONA_MGMT_ENTITLEMENT)) {
3306 		return EPERM;
3307 	}
3308 
3309 	if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_GROUPS) {
3310 		if (px_persona->pspi_ngroups > NGROUPS_MAX) {
3311 			return EINVAL;
3312 		}
3313 	}
3314 
3315 	persona = persona_lookup(px_persona->pspi_id);
3316 	if (!persona) {
3317 		return ESRCH;
3318 	}
3319 
3320 	// non-root process should not be allowed to set persona with uid/gid 0
3321 	if (!kauth_cred_issuser(mycred) &&
3322 	    (px_persona->pspi_uid == 0 || px_persona->pspi_gid == 0)) {
3323 		return EPERM;
3324 	}
3325 
3326 	persona_put(persona);
3327 	return error;
3328 }
3329 
3330 static bool
kauth_cred_model_setpersona(kauth_cred_t model,struct _posix_spawn_persona_info * px_persona)3331 kauth_cred_model_setpersona(
3332 	kauth_cred_t            model,
3333 	struct _posix_spawn_persona_info *px_persona)
3334 {
3335 	bool updated = false;
3336 
3337 	if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_UID) {
3338 		updated |= kauth_cred_model_setresuid(model,
3339 		    px_persona->pspi_uid,
3340 		    px_persona->pspi_uid,
3341 		    px_persona->pspi_uid,
3342 		    KAUTH_UID_NONE);
3343 	}
3344 
3345 	if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_GID) {
3346 		updated |= kauth_cred_model_setresgid(model,
3347 		    px_persona->pspi_gid,
3348 		    px_persona->pspi_gid,
3349 		    px_persona->pspi_gid);
3350 	}
3351 
3352 	if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_GROUPS) {
3353 		updated |= kauth_cred_model_setgroups(model,
3354 		    px_persona->pspi_groups,
3355 		    px_persona->pspi_ngroups,
3356 		    px_persona->pspi_gmuid);
3357 	}
3358 
3359 	return updated;
3360 }
3361 
3362 static int
spawn_persona_adopt(proc_t p,struct _posix_spawn_persona_info * px_persona)3363 spawn_persona_adopt(proc_t p, struct _posix_spawn_persona_info *px_persona)
3364 {
3365 	struct persona *persona = NULL;
3366 
3367 	/*
3368 	 * we want to spawn into the given persona, but we want to override
3369 	 * the kauth with a different UID/GID combo
3370 	 */
3371 	persona = persona_lookup(px_persona->pspi_id);
3372 	if (!persona) {
3373 		return ESRCH;
3374 	}
3375 
3376 	return persona_proc_adopt(p, persona,
3377 	           ^bool (kauth_cred_t parent __unused, kauth_cred_t model) {
3378 		return kauth_cred_model_setpersona(model, px_persona);
3379 	});
3380 }
3381 #endif
3382 
3383 #if __arm64__
3384 #if DEVELOPMENT || DEBUG
3385 TUNABLE(int, legacy_footprint_entitlement_mode, "legacy_footprint_entitlement_mode",
3386     LEGACY_FOOTPRINT_ENTITLEMENT_IGNORE);
3387 
3388 __startup_func
3389 static void
legacy_footprint_entitlement_mode_init(void)3390 legacy_footprint_entitlement_mode_init(void)
3391 {
3392 	/*
3393 	 * legacy_footprint_entitlement_mode specifies the behavior we want associated
3394 	 * with the entitlement. The supported modes are:
3395 	 *
3396 	 * LEGACY_FOOTPRINT_ENTITLEMENT_IGNORE:
3397 	 *	Indicates that we want every process to have the memory accounting
3398 	 *	that is available in iOS 12.0 and beyond.
3399 	 *
3400 	 * LEGACY_FOOTPRINT_ENTITLEMENT_IOS11_ACCT:
3401 	 *	Indicates that for every process that has the 'legacy footprint entitlement',
3402 	 *      we want to give it the old iOS 11.0 accounting behavior which accounted some
3403 	 *	of the process's memory to the kernel.
3404 	 *
3405 	 * LEGACY_FOOTPRINT_ENTITLEMENT_LIMIT_INCREASE:
3406 	 *      Indicates that for every process that has the 'legacy footprint entitlement',
3407 	 *	we want it to have a higher memory limit which will help them acclimate to the
3408 	 *	iOS 12.0 (& beyond) accounting behavior that does the right accounting.
3409 	 *      The bonus added to the system-wide task limit to calculate this higher memory limit
3410 	 *      is available in legacy_footprint_bonus_mb.
3411 	 */
3412 
3413 	if (legacy_footprint_entitlement_mode < LEGACY_FOOTPRINT_ENTITLEMENT_IGNORE ||
3414 	    legacy_footprint_entitlement_mode > LEGACY_FOOTPRINT_ENTITLEMENT_LIMIT_INCREASE) {
3415 		legacy_footprint_entitlement_mode = LEGACY_FOOTPRINT_ENTITLEMENT_LIMIT_INCREASE;
3416 	}
3417 }
3418 STARTUP(TUNABLES, STARTUP_RANK_MIDDLE, legacy_footprint_entitlement_mode_init);
3419 #else
3420 const int legacy_footprint_entitlement_mode = LEGACY_FOOTPRINT_ENTITLEMENT_IGNORE;
3421 #endif
3422 
3423 static inline void
proc_legacy_footprint_entitled(proc_t p,task_t task)3424 proc_legacy_footprint_entitled(proc_t p, task_t task)
3425 {
3426 #pragma unused(p)
3427 	boolean_t legacy_footprint_entitled;
3428 
3429 	switch (legacy_footprint_entitlement_mode) {
3430 	case LEGACY_FOOTPRINT_ENTITLEMENT_IGNORE:
3431 		/* the entitlement is ignored */
3432 		break;
3433 	case LEGACY_FOOTPRINT_ENTITLEMENT_IOS11_ACCT:
3434 		/* the entitlement grants iOS11 legacy accounting */
3435 		legacy_footprint_entitled = memorystatus_task_has_legacy_footprint_entitlement(proc_task(p));
3436 		if (legacy_footprint_entitled) {
3437 			task_set_legacy_footprint(task);
3438 		}
3439 		break;
3440 	case LEGACY_FOOTPRINT_ENTITLEMENT_LIMIT_INCREASE:
3441 		/* the entitlement grants a footprint limit increase */
3442 		legacy_footprint_entitled = memorystatus_task_has_legacy_footprint_entitlement(proc_task(p));
3443 		if (legacy_footprint_entitled) {
3444 			task_set_extra_footprint_limit(task);
3445 		}
3446 		break;
3447 	default:
3448 		break;
3449 	}
3450 }
3451 
3452 static inline void
proc_ios13extended_footprint_entitled(proc_t p,task_t task)3453 proc_ios13extended_footprint_entitled(proc_t p, task_t task)
3454 {
3455 #pragma unused(p)
3456 	boolean_t ios13extended_footprint_entitled;
3457 
3458 	/* the entitlement grants a footprint limit increase */
3459 	ios13extended_footprint_entitled = memorystatus_task_has_ios13extended_footprint_limit(proc_task(p));
3460 	if (ios13extended_footprint_entitled) {
3461 		task_set_ios13extended_footprint_limit(task);
3462 	}
3463 }
3464 
3465 static inline void
proc_increased_memory_limit_entitled(proc_t p,task_t task)3466 proc_increased_memory_limit_entitled(proc_t p, task_t task)
3467 {
3468 	if (memorystatus_task_has_increased_debugging_memory_limit_entitlement(task)) {
3469 		memorystatus_act_on_entitled_developer_task_limit(p);
3470 	} else if (memorystatus_task_has_increased_memory_limit_entitlement(task)) {
3471 		memorystatus_act_on_entitled_task_limit(p);
3472 	}
3473 }
3474 
3475 /*
3476  * Check for any of the various entitlements that permit a higher
3477  * task footprint limit or alternate accounting and apply them.
3478  */
3479 static inline void
proc_footprint_entitlement_hacks(proc_t p,task_t task)3480 proc_footprint_entitlement_hacks(proc_t p, task_t task)
3481 {
3482 	proc_legacy_footprint_entitled(p, task);
3483 	proc_ios13extended_footprint_entitled(p, task);
3484 	proc_increased_memory_limit_entitled(p, task);
3485 }
3486 #endif /* __arm64__ */
3487 
3488 /*
3489  * Processes with certain entitlements are granted a jumbo-size VM map.
3490  */
3491 static inline void
proc_apply_jit_and_vm_policies(struct image_params * imgp,proc_t p,task_t task)3492 proc_apply_jit_and_vm_policies(struct image_params *imgp, proc_t p, task_t task)
3493 {
3494 #if CONFIG_MACF
3495 	bool jit_entitled = false;
3496 #endif /* CONFIG_MACF */
3497 	bool needs_jumbo_va = false;
3498 	bool needs_extra_jumbo_va = false;
3499 	struct _posix_spawnattr *psa = imgp->ip_px_sa;
3500 
3501 #if CONFIG_MACF
3502 	jit_entitled = (mac_proc_check_map_anon(p, proc_ucred_unsafe(p),
3503 	    0, 0, 0, MAP_JIT, NULL) == 0);
3504 	needs_jumbo_va = jit_entitled || IOTaskHasEntitlement(task,
3505 	    "com.apple.developer.kernel.extended-virtual-addressing") ||
3506 	    memorystatus_task_has_increased_memory_limit_entitlement(task) ||
3507 	    memorystatus_task_has_increased_debugging_memory_limit_entitlement(task);
3508 #else
3509 #pragma unused(p)
3510 #endif /* CONFIG_MACF */
3511 
3512 
3513 	if (needs_jumbo_va) {
3514 		vm_map_set_jumbo(get_task_map(task));
3515 	}
3516 
3517 	if (psa && psa->psa_max_addr) {
3518 		vm_map_set_max_addr(get_task_map(task), psa->psa_max_addr, false);
3519 	}
3520 
3521 #if CONFIG_MAP_RANGES
3522 	if (task_is_hardened_binary(task) && !proc_is_simulated(p)) {
3523 		/*
3524 		 * This must be done last as it needs to observe
3525 		 * any kind of VA space growth that was requested.
3526 		 * This is used by the secure allocator, so
3527 		 * must be applied to all hardened binaries
3528 		 */
3529 #if XNU_TARGET_OS_IOS && EXTENDED_USER_VA_SUPPORT
3530 		needs_extra_jumbo_va = IOTaskHasEntitlement(task,
3531 		    "com.apple.kernel.large-file-virtual-addressing");
3532 #endif /* XNU_TARGET_OS_IOS && EXTENDED_USER_VA_SUPPORT */
3533 		vm_map_range_configure(get_task_map(task), needs_extra_jumbo_va);
3534 	}
3535 #else
3536 #pragma unused(needs_extra_jumbo_va)
3537 #endif /* CONFIG_MAP_RANGES */
3538 
3539 #if CONFIG_MACF
3540 	if (jit_entitled) {
3541 		vm_map_set_jit_entitled(get_task_map(task));
3542 
3543 	}
3544 #endif /* CONFIG_MACF */
3545 
3546 #if XNU_TARGET_OS_OSX
3547 	/* TPRO cannot be enforced on binaries that load 3P plugins on macos - rdar://107420220 */
3548 	const bool task_loads_3P_plugins = imgp->ip_flags & IMGPF_3P_PLUGINS;
3549 #endif /* XNU_TARGET_OS_OSX */
3550 
3551 	if (task_is_hardened_binary(task)
3552 #if XNU_TARGET_OS_OSX
3553 	    && !task_loads_3P_plugins
3554 #endif /* XNU_TARGET_OS_OSX */
3555 	    ) {
3556 		/*
3557 		 * Pre-emptively disable TPRO remapping for
3558 		 * hardened binaries (which do not load 3P plugins)
3559 		 */
3560 		vm_map_set_tpro_enforcement(get_task_map(task));
3561 	}
3562 }
3563 
3564 static int
spawn_posix_cred_adopt(proc_t p,struct _posix_spawn_posix_cred_info * px_pcred_info)3565 spawn_posix_cred_adopt(proc_t p,
3566     struct _posix_spawn_posix_cred_info *px_pcred_info)
3567 {
3568 	int error = 0;
3569 
3570 	if (px_pcred_info->pspci_flags & POSIX_SPAWN_POSIX_CRED_GID) {
3571 		struct setgid_args args = {
3572 			.gid = px_pcred_info->pspci_gid,
3573 		};
3574 		error = setgid(p, &args, NULL);
3575 		if (error) {
3576 			return error;
3577 		}
3578 	}
3579 
3580 	if (px_pcred_info->pspci_flags & POSIX_SPAWN_POSIX_CRED_GROUPS) {
3581 		error = setgroups_internal(p,
3582 		    px_pcred_info->pspci_ngroups,
3583 		    px_pcred_info->pspci_groups,
3584 		    px_pcred_info->pspci_gmuid);
3585 		if (error) {
3586 			return error;
3587 		}
3588 	}
3589 
3590 	if (px_pcred_info->pspci_flags & POSIX_SPAWN_POSIX_CRED_UID) {
3591 		struct setuid_args args = {
3592 			.uid = px_pcred_info->pspci_uid,
3593 		};
3594 		error = setuid(p, &args, NULL);
3595 		if (error) {
3596 			return error;
3597 		}
3598 	}
3599 	return 0;
3600 }
3601 
3602 /*
3603  * posix_spawn
3604  *
3605  * Parameters:	uap->pid		Pointer to pid return area
3606  *		uap->fname		File name to exec
3607  *		uap->argp		Argument list
3608  *		uap->envp		Environment list
3609  *
3610  * Returns:	0			Success
3611  *		EINVAL			Invalid argument
3612  *		ENOTSUP			Not supported
3613  *		ENOEXEC			Executable file format error
3614  *	exec_activate_image:EINVAL	Invalid argument
3615  *	exec_activate_image:EACCES	Permission denied
3616  *	exec_activate_image:EINTR	Interrupted function
3617  *	exec_activate_image:ENOMEM	Not enough space
3618  *	exec_activate_image:EFAULT	Bad address
3619  *	exec_activate_image:ENAMETOOLONG	Filename too long
3620  *	exec_activate_image:ENOEXEC	Executable file format error
3621  *	exec_activate_image:ETXTBSY	Text file busy [misuse of error code]
3622  *	exec_activate_image:EAUTH	Image decryption failed
3623  *	exec_activate_image:EBADEXEC	The executable is corrupt/unknown
3624  *	exec_activate_image:???
3625  *	mac_execve_enter:???
3626  *
3627  * TODO:	Expect to need __mac_posix_spawn() at some point...
3628  *		Handle posix_spawnattr_t
3629  *		Handle posix_spawn_file_actions_t
3630  */
3631 int
posix_spawn(proc_t ap,struct posix_spawn_args * uap,int32_t * retval)3632 posix_spawn(proc_t ap, struct posix_spawn_args *uap, int32_t *retval)
3633 {
3634 	proc_t p = ap;
3635 	user_addr_t pid = uap->pid;
3636 	int ival[2];            /* dummy retval for setpgid() */
3637 	char *subsystem_root_path = NULL;
3638 	struct image_params *imgp = NULL;
3639 	struct vnode_attr *vap = NULL;
3640 	struct vnode_attr *origvap = NULL;
3641 	struct uthread  *uthread = 0;   /* compiler complains if not set to 0*/
3642 	int error, sig;
3643 	int is_64 = IS_64BIT_PROCESS(p);
3644 	struct vfs_context context;
3645 	struct user__posix_spawn_args_desc px_args = {};
3646 	struct _posix_spawnattr px_sa = {};
3647 	_posix_spawn_file_actions_t px_sfap = NULL;
3648 	_posix_spawn_port_actions_t px_spap = NULL;
3649 	struct __kern_sigaction vec;
3650 	boolean_t spawn_no_exec = FALSE;
3651 	boolean_t proc_transit_set = TRUE;
3652 	boolean_t proc_signal_set = TRUE;
3653 	boolean_t exec_done = FALSE;
3654 	os_reason_t exec_failure_reason = NULL;
3655 
3656 	struct exec_port_actions port_actions = { };
3657 	vm_size_t px_sa_offset = offsetof(struct _posix_spawnattr, psa_ports);
3658 	task_t old_task = current_task();
3659 	task_t new_task = NULL;
3660 	boolean_t should_release_proc_ref = FALSE;
3661 	void *inherit = NULL;
3662 	uint8_t crash_behavior = 0;
3663 	uint64_t crash_behavior_deadline = 0;
3664 #if CONFIG_EXCLAVES
3665 	char *task_conclave_id = NULL;
3666 #endif
3667 #if CONFIG_PERSONAS
3668 	struct _posix_spawn_persona_info *px_persona = NULL;
3669 #endif
3670 	struct _posix_spawn_posix_cred_info *px_pcred_info = NULL;
3671 	struct {
3672 		struct image_params imgp;
3673 		struct vnode_attr va;
3674 		struct vnode_attr origva;
3675 	} *__spawn_data;
3676 
3677 	/*
3678 	 * Allocate a big chunk for locals instead of using stack since these
3679 	 * structures are pretty big.
3680 	 */
3681 	__spawn_data = kalloc_type(typeof(*__spawn_data), Z_WAITOK | Z_ZERO);
3682 	if (__spawn_data == NULL) {
3683 		error = ENOMEM;
3684 		goto bad;
3685 	}
3686 	imgp = &__spawn_data->imgp;
3687 	vap = &__spawn_data->va;
3688 	origvap = &__spawn_data->origva;
3689 
3690 	/* Initialize the common data in the image_params structure */
3691 	imgp->ip_user_fname = uap->path;
3692 	imgp->ip_user_argv = uap->argv;
3693 	imgp->ip_user_envv = uap->envp;
3694 	imgp->ip_vattr = vap;
3695 	imgp->ip_origvattr = origvap;
3696 	imgp->ip_vfs_context = &context;
3697 	imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT_ADDR : IMGPF_NONE);
3698 	imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32);
3699 	imgp->ip_mac_return = 0;
3700 	imgp->ip_px_persona = NULL;
3701 	imgp->ip_px_pcred_info = NULL;
3702 	imgp->ip_cs_error = OS_REASON_NULL;
3703 	imgp->ip_simulator_binary = IMGPF_SB_DEFAULT;
3704 	imgp->ip_subsystem_root_path = NULL;
3705 	imgp->ip_inherited_shared_region_id = NULL;
3706 	imgp->ip_inherited_jop_pid = 0;
3707 	uthread_set_exec_data(current_uthread(), imgp);
3708 
3709 	if (uap->adesc != USER_ADDR_NULL) {
3710 		if (is_64) {
3711 			error = copyin(uap->adesc, &px_args, sizeof(px_args));
3712 		} else {
3713 			struct user32__posix_spawn_args_desc px_args32;
3714 
3715 			error = copyin(uap->adesc, &px_args32, sizeof(px_args32));
3716 
3717 			/*
3718 			 * Convert arguments descriptor from external 32 bit
3719 			 * representation to internal 64 bit representation
3720 			 */
3721 			px_args.attr_size = px_args32.attr_size;
3722 			px_args.attrp = CAST_USER_ADDR_T(px_args32.attrp);
3723 			px_args.file_actions_size = px_args32.file_actions_size;
3724 			px_args.file_actions = CAST_USER_ADDR_T(px_args32.file_actions);
3725 			px_args.port_actions_size = px_args32.port_actions_size;
3726 			px_args.port_actions = CAST_USER_ADDR_T(px_args32.port_actions);
3727 			px_args.mac_extensions_size = px_args32.mac_extensions_size;
3728 			px_args.mac_extensions = CAST_USER_ADDR_T(px_args32.mac_extensions);
3729 			px_args.coal_info_size = px_args32.coal_info_size;
3730 			px_args.coal_info = CAST_USER_ADDR_T(px_args32.coal_info);
3731 			px_args.persona_info_size = px_args32.persona_info_size;
3732 			px_args.persona_info = CAST_USER_ADDR_T(px_args32.persona_info);
3733 			px_args.posix_cred_info_size = px_args32.posix_cred_info_size;
3734 			px_args.posix_cred_info = CAST_USER_ADDR_T(px_args32.posix_cred_info);
3735 			px_args.subsystem_root_path_size = px_args32.subsystem_root_path_size;
3736 			px_args.subsystem_root_path = CAST_USER_ADDR_T(px_args32.subsystem_root_path);
3737 			px_args.conclave_id_size = px_args32.conclave_id_size;
3738 			px_args.conclave_id = CAST_USER_ADDR_T(px_args32.conclave_id);
3739 		}
3740 		if (error) {
3741 			goto bad;
3742 		}
3743 
3744 		if (px_args.attr_size != 0) {
3745 			/*
3746 			 * We are not copying the port_actions pointer,
3747 			 * because we already have it from px_args.
3748 			 * This is a bit fragile: <rdar://problem/16427422>
3749 			 */
3750 
3751 			if ((error = copyin(px_args.attrp, &px_sa, px_sa_offset)) != 0) {
3752 				goto bad;
3753 			}
3754 
3755 			imgp->ip_px_sa = &px_sa;
3756 		}
3757 		if (px_args.file_actions_size != 0) {
3758 			/* Limit file_actions to allowed number of open files */
3759 			size_t maxfa_size = PSF_ACTIONS_SIZE(proc_limitgetcur_nofile(p));
3760 
3761 			if (px_args.file_actions_size < PSF_ACTIONS_SIZE(1) ||
3762 			    maxfa_size == 0 || px_args.file_actions_size > maxfa_size) {
3763 				error = EINVAL;
3764 				goto bad;
3765 			}
3766 
3767 			px_sfap = kalloc_data(px_args.file_actions_size, Z_WAITOK);
3768 			if (px_sfap == NULL) {
3769 				error = ENOMEM;
3770 				goto bad;
3771 			}
3772 			imgp->ip_px_sfa = px_sfap;
3773 
3774 			if ((error = copyin(px_args.file_actions, px_sfap,
3775 			    px_args.file_actions_size)) != 0) {
3776 				goto bad;
3777 			}
3778 
3779 			/* Verify that the action count matches the struct size */
3780 			size_t psfsize = PSF_ACTIONS_SIZE(px_sfap->psfa_act_count);
3781 			if (psfsize == 0 || psfsize != px_args.file_actions_size) {
3782 				error = EINVAL;
3783 				goto bad;
3784 			}
3785 		}
3786 		if (px_args.port_actions_size != 0) {
3787 			/* Limit port_actions to one page of data */
3788 			if (px_args.port_actions_size < PS_PORT_ACTIONS_SIZE(1) ||
3789 			    px_args.port_actions_size > PAGE_SIZE) {
3790 				error = EINVAL;
3791 				goto bad;
3792 			}
3793 
3794 			px_spap = kalloc_data(px_args.port_actions_size, Z_WAITOK);
3795 			if (px_spap == NULL) {
3796 				error = ENOMEM;
3797 				goto bad;
3798 			}
3799 			imgp->ip_px_spa = px_spap;
3800 
3801 			if ((error = copyin(px_args.port_actions, px_spap,
3802 			    px_args.port_actions_size)) != 0) {
3803 				goto bad;
3804 			}
3805 
3806 			/* Verify that the action count matches the struct size */
3807 			size_t pasize = PS_PORT_ACTIONS_SIZE(px_spap->pspa_count);
3808 			if (pasize == 0 || pasize != px_args.port_actions_size) {
3809 				error = EINVAL;
3810 				goto bad;
3811 			}
3812 		}
3813 #if CONFIG_PERSONAS
3814 		/* copy in the persona info */
3815 		if (px_args.persona_info_size != 0 && px_args.persona_info != 0) {
3816 			/* for now, we need the exact same struct in user space */
3817 			if (px_args.persona_info_size != sizeof(*px_persona)) {
3818 				error = ERANGE;
3819 				goto bad;
3820 			}
3821 
3822 			px_persona = kalloc_data(px_args.persona_info_size, Z_WAITOK);
3823 			if (px_persona == NULL) {
3824 				error = ENOMEM;
3825 				goto bad;
3826 			}
3827 			imgp->ip_px_persona = px_persona;
3828 
3829 			if ((error = copyin(px_args.persona_info, px_persona,
3830 			    px_args.persona_info_size)) != 0) {
3831 				goto bad;
3832 			}
3833 			if ((error = spawn_validate_persona(px_persona)) != 0) {
3834 				goto bad;
3835 			}
3836 		}
3837 #endif
3838 		/* copy in the posix cred info */
3839 		if (px_args.posix_cred_info_size != 0 && px_args.posix_cred_info != 0) {
3840 			/* for now, we need the exact same struct in user space */
3841 			if (px_args.posix_cred_info_size != sizeof(*px_pcred_info)) {
3842 				error = ERANGE;
3843 				goto bad;
3844 			}
3845 
3846 			if (!kauth_cred_issuser(kauth_cred_get())) {
3847 				error = EPERM;
3848 				goto bad;
3849 			}
3850 
3851 			px_pcred_info = kalloc_data(px_args.posix_cred_info_size, Z_WAITOK);
3852 			if (px_pcred_info == NULL) {
3853 				error = ENOMEM;
3854 				goto bad;
3855 			}
3856 			imgp->ip_px_pcred_info = px_pcred_info;
3857 
3858 			if ((error = copyin(px_args.posix_cred_info, px_pcred_info,
3859 			    px_args.posix_cred_info_size)) != 0) {
3860 				goto bad;
3861 			}
3862 
3863 			if (px_pcred_info->pspci_flags & POSIX_SPAWN_POSIX_CRED_GROUPS) {
3864 				if (px_pcred_info->pspci_ngroups > NGROUPS_MAX) {
3865 					error = EINVAL;
3866 					goto bad;
3867 				}
3868 			}
3869 		}
3870 #if CONFIG_MACF
3871 		if (px_args.mac_extensions_size != 0) {
3872 			if ((error = spawn_copyin_macpolicyinfo(&px_args, (struct ip_px_smpx_s *)&imgp->ip_px_smpx)) != 0) {
3873 				goto bad;
3874 			}
3875 		}
3876 #endif /* CONFIG_MACF */
3877 		if ((px_args.subsystem_root_path_size > 0) && (px_args.subsystem_root_path_size <= MAXPATHLEN)) {
3878 			/*
3879 			 * If a valid-looking subsystem root has been
3880 			 * specified...
3881 			 */
3882 			if (IOTaskHasEntitlement(old_task, SPAWN_SUBSYSTEM_ROOT_ENTITLEMENT)) {
3883 				/*
3884 				 * ...AND the parent has the entitlement, copy
3885 				 * the subsystem root path in.
3886 				 */
3887 				subsystem_root_path = zalloc_flags(ZV_NAMEI,
3888 				    Z_WAITOK | Z_ZERO | Z_NOFAIL);
3889 
3890 				if ((error = copyin(px_args.subsystem_root_path, subsystem_root_path, px_args.subsystem_root_path_size))) {
3891 					goto bad;
3892 				}
3893 
3894 				/* Paranoia */
3895 				subsystem_root_path[px_args.subsystem_root_path_size - 1] = 0;
3896 			}
3897 		}
3898 #if CONFIG_EXCLAVES
3899 
3900 		/*
3901 		 * Calling exclaves_boot_wait() ensures that the conclave name
3902 		 * id will only be set when exclaves are actually
3903 		 * supported/enabled. In practice this will never actually block
3904 		 * as by the time this is called the system will have booted to
3905 		 * EXCLAVECORE if it's supported/enabled.
3906 		 */
3907 		if ((px_args.conclave_id_size > 0) && (px_args.conclave_id_size <= MAXCONCLAVENAME) &&
3908 		    (exclaves_boot_wait(EXCLAVES_BOOT_STAGE_EXCLAVECORE) == KERN_SUCCESS)) {
3909 			if (px_args.conclave_id) {
3910 				if (imgp->ip_px_sa != NULL && (px_sa.psa_flags & POSIX_SPAWN_SETEXEC)) {
3911 					/* Conclave id could be set only for true spawn */
3912 					error = EINVAL;
3913 					goto bad;
3914 				}
3915 				task_conclave_id = kalloc_data(MAXCONCLAVENAME,
3916 				    Z_WAITOK | Z_ZERO | Z_NOFAIL);
3917 				if ((error = copyin(px_args.conclave_id, task_conclave_id, MAXCONCLAVENAME))) {
3918 					goto bad;
3919 				}
3920 				task_conclave_id[MAXCONCLAVENAME - 1] = 0;
3921 			}
3922 		}
3923 #endif
3924 	}
3925 
3926 	if (IOTaskHasEntitlement(old_task, SPAWN_SET_PANIC_CRASH_BEHAVIOR)) {
3927 		/* Truncate to uint8_t since we only support 2 flags for now */
3928 		crash_behavior = (uint8_t)px_sa.psa_crash_behavior;
3929 		crash_behavior_deadline = px_sa.psa_crash_behavior_deadline;
3930 	}
3931 
3932 	/* set uthread to parent */
3933 	uthread = current_uthread();
3934 
3935 	/*
3936 	 * <rdar://6640530>; this does not result in a behaviour change
3937 	 * relative to Leopard, so there should not be any existing code
3938 	 * which depends on it.
3939 	 */
3940 
3941 	if (imgp->ip_px_sa != NULL) {
3942 		struct _posix_spawnattr *psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
3943 		if ((psa->psa_options & PSA_OPTION_PLUGIN_HOST_DISABLE_A_KEYS) == PSA_OPTION_PLUGIN_HOST_DISABLE_A_KEYS) {
3944 			imgp->ip_flags |= IMGPF_PLUGIN_HOST_DISABLE_A_KEYS;
3945 		}
3946 
3947 
3948 #if (DEVELOPMENT || DEBUG)
3949 		if ((psa->psa_options & PSA_OPTION_ALT_ROSETTA) == PSA_OPTION_ALT_ROSETTA) {
3950 			imgp->ip_flags |= (IMGPF_ROSETTA | IMGPF_ALT_ROSETTA);
3951 		}
3952 #endif /* (DEVELOPMENT || DEBUG) */
3953 
3954 		if ((error = exec_validate_spawnattr_policy(psa->psa_apptype)) != 0) {
3955 			goto bad;
3956 		}
3957 	}
3958 
3959 	/*
3960 	 * If we don't have the extension flag that turns "posix_spawn()"
3961 	 * into "execve() with options", then we will be creating a new
3962 	 * process which does not inherit memory from the parent process,
3963 	 * which is one of the most expensive things about using fork()
3964 	 * and execve().
3965 	 */
3966 	if (imgp->ip_px_sa == NULL || !(px_sa.psa_flags & POSIX_SPAWN_SETEXEC)) {
3967 		/* Set the new task's coalition, if it is requested.  */
3968 		coalition_t coal[COALITION_NUM_TYPES] = { COALITION_NULL };
3969 #if CONFIG_COALITIONS
3970 		int i, ncoals;
3971 		kern_return_t kr = KERN_SUCCESS;
3972 		struct _posix_spawn_coalition_info coal_info;
3973 		int coal_role[COALITION_NUM_TYPES];
3974 
3975 		if (imgp->ip_px_sa == NULL || !px_args.coal_info) {
3976 			goto do_fork1;
3977 		}
3978 
3979 		memset(&coal_info, 0, sizeof(coal_info));
3980 
3981 		if (px_args.coal_info_size > sizeof(coal_info)) {
3982 			px_args.coal_info_size = sizeof(coal_info);
3983 		}
3984 		error = copyin(px_args.coal_info,
3985 		    &coal_info, px_args.coal_info_size);
3986 		if (error != 0) {
3987 			goto bad;
3988 		}
3989 
3990 		ncoals = 0;
3991 		for (i = 0; i < COALITION_NUM_TYPES; i++) {
3992 			uint64_t cid = coal_info.psci_info[i].psci_id;
3993 			if (cid != 0) {
3994 				/*
3995 				 * don't allow tasks which are not in a
3996 				 * privileged coalition to spawn processes
3997 				 * into coalitions other than their own
3998 				 */
3999 				if (!task_is_in_privileged_coalition(proc_task(p), i) &&
4000 				    !IOTaskHasEntitlement(proc_task(p), COALITION_SPAWN_ENTITLEMENT)) {
4001 					coal_dbg("ERROR: %d not in privilegd "
4002 					    "coalition of type %d",
4003 					    proc_getpid(p), i);
4004 					spawn_coalitions_release_all(coal);
4005 					error = EPERM;
4006 					goto bad;
4007 				}
4008 
4009 				coal_dbg("searching for coalition id:%llu", cid);
4010 				/*
4011 				 * take a reference and activation on the
4012 				 * coalition to guard against free-while-spawn
4013 				 * races
4014 				 */
4015 				coal[i] = coalition_find_and_activate_by_id(cid);
4016 				if (coal[i] == COALITION_NULL) {
4017 					coal_dbg("could not find coalition id:%llu "
4018 					    "(perhaps it has been terminated or reaped)", cid);
4019 					/*
4020 					 * release any other coalition's we
4021 					 * may have a reference to
4022 					 */
4023 					spawn_coalitions_release_all(coal);
4024 					error = ESRCH;
4025 					goto bad;
4026 				}
4027 				if (coalition_type(coal[i]) != i) {
4028 					coal_dbg("coalition with id:%lld is not of type:%d"
4029 					    " (it's type:%d)", cid, i, coalition_type(coal[i]));
4030 					spawn_coalitions_release_all(coal);
4031 					error = ESRCH;
4032 					goto bad;
4033 				}
4034 				coal_role[i] = coal_info.psci_info[i].psci_role;
4035 				ncoals++;
4036 			}
4037 		}
4038 		if (ncoals < COALITION_NUM_TYPES) {
4039 			/*
4040 			 * If the user is attempting to spawn into a subset of
4041 			 * the known coalition types, then make sure they have
4042 			 * _at_least_ specified a resource coalition. If not,
4043 			 * the following fork1() call will implicitly force an
4044 			 * inheritance from 'p' and won't actually spawn the
4045 			 * new task into the coalitions the user specified.
4046 			 * (also the call to coalitions_set_roles will panic)
4047 			 */
4048 			if (coal[COALITION_TYPE_RESOURCE] == COALITION_NULL) {
4049 				spawn_coalitions_release_all(coal);
4050 				error = EINVAL;
4051 				goto bad;
4052 			}
4053 		}
4054 do_fork1:
4055 #endif /* CONFIG_COALITIONS */
4056 
4057 		/*
4058 		 * note that this will implicitly inherit the
4059 		 * caller's persona (if it exists)
4060 		 */
4061 		error = fork1(p, &imgp->ip_new_thread, PROC_CREATE_SPAWN, coal);
4062 		/* returns a thread and task reference */
4063 
4064 		if (error == 0) {
4065 			new_task = get_threadtask(imgp->ip_new_thread);
4066 		}
4067 #if CONFIG_COALITIONS
4068 		/* set the roles of this task within each given coalition */
4069 		if (error == 0) {
4070 			kr = coalitions_set_roles(coal, new_task, coal_role);
4071 			if (kr != KERN_SUCCESS) {
4072 				error = EINVAL;
4073 			}
4074 			if (kdebug_debugid_enabled(MACHDBG_CODE(DBG_MACH_COALITION,
4075 			    MACH_COALITION_ADOPT))) {
4076 				for (i = 0; i < COALITION_NUM_TYPES; i++) {
4077 					if (coal[i] != COALITION_NULL) {
4078 						/*
4079 						 * On 32-bit targets, uniqueid
4080 						 * will get truncated to 32 bits
4081 						 */
4082 						KDBG_RELEASE(MACHDBG_CODE(
4083 							    DBG_MACH_COALITION,
4084 							    MACH_COALITION_ADOPT),
4085 						    coalition_id(coal[i]),
4086 						    get_task_uniqueid(new_task));
4087 					}
4088 				}
4089 			}
4090 		}
4091 
4092 		/* drop our references and activations - fork1() now holds them */
4093 		spawn_coalitions_release_all(coal);
4094 #endif /* CONFIG_COALITIONS */
4095 		if (error != 0) {
4096 			goto bad;
4097 		}
4098 		imgp->ip_flags |= IMGPF_SPAWN;  /* spawn w/o exec */
4099 		spawn_no_exec = TRUE;           /* used in later tests */
4100 	} else {
4101 		/* Adjust the user proc count */
4102 		(void)chgproccnt(kauth_getruid(), 1);
4103 		/*
4104 		 * For execve case, create a new proc, task and thread
4105 		 * but don't make the proc visible to userland. After
4106 		 * image activation, the new proc would take place of
4107 		 * the old proc in pid hash and other lists that make
4108 		 * the proc visible to the system.
4109 		 */
4110 		imgp->ip_new_thread = cloneproc(old_task, NULL, p, CLONEPROC_EXEC);
4111 
4112 		/* task and thread ref returned by cloneproc */
4113 		if (imgp->ip_new_thread == NULL) {
4114 			(void)chgproccnt(kauth_getruid(), -1);
4115 			error = ENOMEM;
4116 			goto bad;
4117 		}
4118 
4119 		new_task = get_threadtask(imgp->ip_new_thread);
4120 		imgp->ip_flags |= IMGPF_EXEC;
4121 	}
4122 
4123 	p = (proc_t)get_bsdthreadtask_info(imgp->ip_new_thread);
4124 
4125 	if (spawn_no_exec) {
4126 		/*
4127 		 * We had to wait until this point before firing the
4128 		 * proc:::create probe, otherwise p would not point to the
4129 		 * child process.
4130 		 */
4131 		DTRACE_PROC1(create, proc_t, p);
4132 	}
4133 	assert(p != NULL);
4134 
4135 	if (subsystem_root_path) {
4136 		/* If a subsystem root was specified, swap it in */
4137 		char * old_subsystem_root_path = p->p_subsystem_root_path;
4138 		p->p_subsystem_root_path = subsystem_root_path;
4139 		subsystem_root_path = old_subsystem_root_path;
4140 	}
4141 
4142 	p->p_crash_behavior = crash_behavior;
4143 	p->p_crash_behavior_deadline = crash_behavior_deadline;
4144 
4145 	p->p_crash_count = px_sa.psa_crash_count;
4146 	p->p_throttle_timeout = px_sa.psa_throttle_timeout;
4147 
4148 	/* We'll need the subsystem root for setting up Apple strings */
4149 	imgp->ip_subsystem_root_path = p->p_subsystem_root_path;
4150 
4151 	context.vc_thread = imgp->ip_new_thread;
4152 	context.vc_ucred = proc_ucred_unsafe(p);  /* in init */
4153 
4154 	/*
4155 	 * Post fdt_fork(), pre exec_handle_sugid() - this is where we want
4156 	 * to handle the file_actions.
4157 	 */
4158 
4159 	/* Has spawn file actions? */
4160 	if (imgp->ip_px_sfa != NULL) {
4161 		/*
4162 		 * The POSIX_SPAWN_CLOEXEC_DEFAULT flag
4163 		 * is handled in exec_handle_file_actions().
4164 		 */
4165 #if CONFIG_AUDIT
4166 		/*
4167 		 * The file actions auditing can overwrite the upath of
4168 		 * AUE_POSIX_SPAWN audit record.  Save the audit record.
4169 		 */
4170 		struct kaudit_record *save_uu_ar = uthread->uu_ar;
4171 		uthread->uu_ar = NULL;
4172 #endif
4173 		error = exec_handle_file_actions(imgp,
4174 		    imgp->ip_px_sa != NULL ? px_sa.psa_flags : 0);
4175 #if CONFIG_AUDIT
4176 		/* Restore the AUE_POSIX_SPAWN audit record. */
4177 		uthread->uu_ar = save_uu_ar;
4178 #endif
4179 		if (error != 0) {
4180 			goto bad;
4181 		}
4182 	}
4183 
4184 	/* Has spawn port actions? */
4185 	if (imgp->ip_px_spa != NULL) {
4186 #if CONFIG_AUDIT
4187 		/*
4188 		 * Do the same for the port actions as we did for the file
4189 		 * actions.  Save the AUE_POSIX_SPAWN audit record.
4190 		 */
4191 		struct kaudit_record *save_uu_ar = uthread->uu_ar;
4192 		uthread->uu_ar = NULL;
4193 #endif
4194 		error = exec_handle_port_actions(imgp, &port_actions);
4195 #if CONFIG_AUDIT
4196 		/* Restore the AUE_POSIX_SPAWN audit record. */
4197 		uthread->uu_ar = save_uu_ar;
4198 #endif
4199 		if (error != 0) {
4200 			goto bad;
4201 		}
4202 	}
4203 
4204 	/* Has spawn attr? */
4205 	if (imgp->ip_px_sa != NULL) {
4206 		/*
4207 		 * Reset UID/GID to parent's RUID/RGID; This works only
4208 		 * because the operation occurs before the call
4209 		 * to exec_handle_sugid() by the image activator called
4210 		 * from exec_activate_image().
4211 		 *
4212 		 * POSIX requires that any setuid/setgid bits on the process
4213 		 * image will take precedence over the spawn attributes
4214 		 * (re)setting them.
4215 		 *
4216 		 * Modifications to p_ucred must be guarded using the
4217 		 * proc's ucred lock. This prevents others from accessing
4218 		 * a garbage credential.
4219 		 */
4220 		if (px_sa.psa_flags & POSIX_SPAWN_RESETIDS) {
4221 			kauth_cred_proc_update(p, PROC_SETTOKEN_NONE,
4222 			    ^bool (kauth_cred_t parent __unused, kauth_cred_t model){
4223 				return kauth_cred_model_setuidgid(model,
4224 				kauth_cred_getruid(parent),
4225 				kauth_cred_getrgid(parent));
4226 			});
4227 		}
4228 
4229 		if (imgp->ip_px_pcred_info) {
4230 			if (!spawn_no_exec) {
4231 				error = ENOTSUP;
4232 				goto bad;
4233 			}
4234 
4235 			error = spawn_posix_cred_adopt(p, imgp->ip_px_pcred_info);
4236 			if (error != 0) {
4237 				goto bad;
4238 			}
4239 		}
4240 
4241 #if CONFIG_PERSONAS
4242 		if (imgp->ip_px_persona != NULL) {
4243 			if (!spawn_no_exec) {
4244 				error = ENOTSUP;
4245 				goto bad;
4246 			}
4247 
4248 			/*
4249 			 * If we were asked to spawn a process into a new persona,
4250 			 * do the credential switch now (which may override the UID/GID
4251 			 * inherit done just above). It's important to do this switch
4252 			 * before image activation both for reasons stated above, and
4253 			 * to ensure that the new persona has access to the image/file
4254 			 * being executed.
4255 			 */
4256 			error = spawn_persona_adopt(p, imgp->ip_px_persona);
4257 			if (error != 0) {
4258 				goto bad;
4259 			}
4260 		}
4261 #endif /* CONFIG_PERSONAS */
4262 #if !SECURE_KERNEL
4263 		/*
4264 		 * Disable ASLR for the spawned process.
4265 		 *
4266 		 * But only do so if we are not embedded + RELEASE.
4267 		 * While embedded allows for a boot-arg (-disable_aslr)
4268 		 * to deal with this (which itself is only honored on
4269 		 * DEVELOPMENT or DEBUG builds of xnu), it is often
4270 		 * useful or necessary to disable ASLR on a per-process
4271 		 * basis for unit testing and debugging.
4272 		 */
4273 		if (px_sa.psa_flags & _POSIX_SPAWN_DISABLE_ASLR) {
4274 			OSBitOrAtomic(P_DISABLE_ASLR, &p->p_flag);
4275 		}
4276 #endif /* !SECURE_KERNEL */
4277 
4278 		/* Randomize high bits of ASLR slide */
4279 		if (px_sa.psa_flags & _POSIX_SPAWN_HIGH_BITS_ASLR) {
4280 			imgp->ip_flags |= IMGPF_HIGH_BITS_ASLR;
4281 		}
4282 
4283 #if !SECURE_KERNEL
4284 		/*
4285 		 * Forcibly disallow execution from data pages for the spawned process
4286 		 * even if it would otherwise be permitted by the architecture default.
4287 		 */
4288 		if (px_sa.psa_flags & _POSIX_SPAWN_ALLOW_DATA_EXEC) {
4289 			imgp->ip_flags |= IMGPF_ALLOW_DATA_EXEC;
4290 		}
4291 #endif /* !SECURE_KERNEL */
4292 
4293 #if     __has_feature(ptrauth_calls)
4294 		if (vm_shared_region_reslide_aslr && is_64 && (px_sa.psa_flags & _POSIX_SPAWN_RESLIDE)) {
4295 			imgp->ip_flags |= IMGPF_RESLIDE;
4296 		}
4297 #endif /* __has_feature(ptrauth_calls) */
4298 
4299 		if ((px_sa.psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK) ==
4300 		    POSIX_SPAWN_PROC_TYPE_DRIVER) {
4301 			imgp->ip_flags |= IMGPF_DRIVER;
4302 		}
4303 	}
4304 
4305 	/*
4306 	 * Disable ASLR during image activation.  This occurs either if the
4307 	 * _POSIX_SPAWN_DISABLE_ASLR attribute was found above or if
4308 	 * P_DISABLE_ASLR was inherited from the parent process.
4309 	 */
4310 	if (p->p_flag & P_DISABLE_ASLR) {
4311 		imgp->ip_flags |= IMGPF_DISABLE_ASLR;
4312 	}
4313 
4314 	/*
4315 	 * Clear transition flag so we won't hang if exec_activate_image() causes
4316 	 * an automount (and launchd does a proc sysctl to service it).
4317 	 *
4318 	 * <rdar://problem/6848672>, <rdar://problem/5959568>.
4319 	 */
4320 	proc_transend(p, 0);
4321 	proc_transit_set = 0;
4322 
4323 	if (!spawn_no_exec) {
4324 		/*
4325 		 * Clear the signal lock in case of exec, since
4326 		 * image activation uses psignal on child process.
4327 		 */
4328 		proc_signalend(p, 0);
4329 		proc_signal_set = 0;
4330 	}
4331 
4332 #if MAC_SPAWN   /* XXX */
4333 	if (uap->mac_p != USER_ADDR_NULL) {
4334 		error = mac_execve_enter(uap->mac_p, imgp);
4335 		if (error) {
4336 			goto bad;
4337 		}
4338 	}
4339 #endif
4340 	/*
4341 	 * Activate the image.
4342 	 * Warning: If activation failed after point of no return, it returns error
4343 	 * as 0 and pretends the call succeeded.
4344 	 */
4345 	error = exec_activate_image(imgp);
4346 #if defined(HAS_APPLE_PAC)
4347 	const uint8_t disable_user_jop = imgp->ip_flags & IMGPF_NOJOP ? TRUE : FALSE;
4348 	ml_task_set_jop_pid_from_shared_region(new_task, disable_user_jop);
4349 	ml_task_set_disable_user_jop(new_task, disable_user_jop);
4350 	ml_thread_set_disable_user_jop(imgp->ip_new_thread, disable_user_jop);
4351 	ml_thread_set_jop_pid(imgp->ip_new_thread, new_task);
4352 #endif
4353 
4354 	/*
4355 	 * If you've come here to add support for some new HW feature or some per-process or per-vmmap
4356 	 * or per-pmap flag that needs to be set before the process runs, or are in general lost, here
4357 	 * is some help. This summary was accurate as of Jul 2022. Use git log as needed. This comment
4358 	 * is here to prevent a recurrence of rdar://96307913
4359 	 *
4360 	 * In posix_spawn, following is what happens:
4361 	 * 1. Lots of prep and checking work
4362 	 * 2. Image activation via exec_activate_image(). The new task will get a new pmap here
4363 	 * 3. More prep work. (YOU ARE HERE)
4364 	 * 4. exec_resettextvp() is called
4365 	 * 5. At this point it is safe to check entitlements and code signatures
4366 	 * 6. task_clear_return_wait(get_threadtask(imgp->ip_new_thread), TCRW_CLEAR_INITIAL_WAIT);
4367 	 *    The new thread is allowed to run in kernel. It cannot yet get to userland
4368 	 * 7. More things done here. This is your chance to affect the task before it runs in
4369 	 *    userspace
4370 	 * 8. task_clear_return_wait(get_threadtask(imgp->ip_new_thread), TCRW_CLEAR_FINAL_WAIT);
4371 	 *     The new thread is allowed to run in userland
4372 	 */
4373 
4374 	if (error == 0 && !spawn_no_exec) {
4375 		p = proc_exec_switch_task(current_proc(), p, old_task, new_task, imgp, &inherit);
4376 		/* proc ref returned */
4377 		should_release_proc_ref = TRUE;
4378 	}
4379 
4380 	if (error == 0) {
4381 		/* process completed the exec, but may have failed after point of no return */
4382 		exec_done = TRUE;
4383 	}
4384 
4385 #if CONFIG_EXCLAVES
4386 	if (!error && task_conclave_id != NULL) {
4387 		kern_return_t kr;
4388 		kr = task_add_conclave(new_task, imgp->ip_vp, (int64_t)imgp->ip_arch_offset,
4389 		    task_conclave_id);
4390 		if (kr != KERN_SUCCESS) {
4391 			error = EINVAL;
4392 			goto bad;
4393 		}
4394 	}
4395 #endif
4396 
4397 	if (!error && imgp->ip_px_sa != NULL) {
4398 		thread_t child_thread = imgp->ip_new_thread;
4399 		uthread_t child_uthread = get_bsdthread_info(child_thread);
4400 
4401 		/*
4402 		 * Because of POSIX_SPAWN_SETEXEC, we need to handle this after image
4403 		 * activation, else when image activation fails (before the point of no
4404 		 * return) would leave the parent process in a modified state.
4405 		 */
4406 		if (px_sa.psa_flags & POSIX_SPAWN_SETPGROUP) {
4407 			struct setpgid_args spga;
4408 			spga.pid = proc_getpid(p);
4409 			spga.pgid = px_sa.psa_pgroup;
4410 			/*
4411 			 * Effectively, call setpgid() system call; works
4412 			 * because there are no pointer arguments.
4413 			 */
4414 			if ((error = setpgid(p, &spga, ival)) != 0) {
4415 				goto bad_px_sa;
4416 			}
4417 		}
4418 
4419 		if (px_sa.psa_flags & POSIX_SPAWN_SETSID) {
4420 			error = setsid_internal(p);
4421 			if (error != 0) {
4422 				goto bad_px_sa;
4423 			}
4424 		}
4425 
4426 		/*
4427 		 * If we have a spawn attr, and it contains signal related flags,
4428 		 * the we need to process them in the "context" of the new child
4429 		 * process, so we have to process it following image activation,
4430 		 * prior to making the thread runnable in user space.  This is
4431 		 * necessitated by some signal information being per-thread rather
4432 		 * than per-process, and we don't have the new allocation in hand
4433 		 * until after the image is activated.
4434 		 */
4435 
4436 		/*
4437 		 * Mask a list of signals, instead of them being unmasked, if
4438 		 * they were unmasked in the parent; note that some signals
4439 		 * are not maskable.
4440 		 */
4441 		if (px_sa.psa_flags & POSIX_SPAWN_SETSIGMASK) {
4442 			child_uthread->uu_sigmask = (px_sa.psa_sigmask & ~sigcantmask);
4443 		}
4444 		/*
4445 		 * Default a list of signals instead of ignoring them, if
4446 		 * they were ignored in the parent.  Note that we pass
4447 		 * spawn_no_exec to setsigvec() to indicate that we called
4448 		 * fork1() and therefore do not need to call proc_signalstart()
4449 		 * internally.
4450 		 */
4451 		if (px_sa.psa_flags & POSIX_SPAWN_SETSIGDEF) {
4452 			vec.sa_handler = SIG_DFL;
4453 			vec.sa_tramp = 0;
4454 			vec.sa_mask = 0;
4455 			vec.sa_flags = 0;
4456 			for (sig = 1; sig < NSIG; sig++) {
4457 				if (px_sa.psa_sigdefault & (1 << (sig - 1))) {
4458 					error = setsigvec(p, child_thread, sig, &vec, spawn_no_exec);
4459 				}
4460 			}
4461 		}
4462 
4463 		/*
4464 		 * Activate the CPU usage monitor, if requested. This is done via a task-wide, per-thread CPU
4465 		 * usage limit, which will generate a resource exceeded exception if any one thread exceeds the
4466 		 * limit.
4467 		 *
4468 		 * Userland gives us interval in seconds, and the kernel SPI expects nanoseconds.
4469 		 */
4470 		if ((px_sa.psa_cpumonitor_percent != 0) && (px_sa.psa_cpumonitor_percent < UINT8_MAX)) {
4471 			/*
4472 			 * Always treat a CPU monitor activation coming from spawn as entitled. Requiring
4473 			 * an entitlement to configure the monitor a certain way seems silly, since
4474 			 * whomever is turning it on could just as easily choose not to do so.
4475 			 */
4476 			error = proc_set_task_ruse_cpu(proc_task(p),
4477 			    TASK_POLICY_RESOURCE_ATTRIBUTE_NOTIFY_EXC,
4478 			    (uint8_t)px_sa.psa_cpumonitor_percent,
4479 			    px_sa.psa_cpumonitor_interval * NSEC_PER_SEC,
4480 			    0, TRUE);
4481 		}
4482 
4483 
4484 		if (px_pcred_info &&
4485 		    (px_pcred_info->pspci_flags & POSIX_SPAWN_POSIX_CRED_LOGIN)) {
4486 			/*
4487 			 * setlogin() must happen after setsid()
4488 			 */
4489 			setlogin_internal(p, px_pcred_info->pspci_login);
4490 		}
4491 
4492 bad_px_sa:
4493 		if (error != 0) {
4494 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
4495 			    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_PSATTR, 0, 0);
4496 			exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_PSATTR);
4497 		}
4498 	}
4499 
4500 bad:
4501 
4502 	if (error == 0) {
4503 		/* reset delay idle sleep status if set */
4504 #if CONFIG_DELAY_IDLE_SLEEP
4505 		if ((p->p_flag & P_DELAYIDLESLEEP) == P_DELAYIDLESLEEP) {
4506 			OSBitAndAtomic(~((uint32_t)P_DELAYIDLESLEEP), &p->p_flag);
4507 		}
4508 #endif /* CONFIG_DELAY_IDLE_SLEEP */
4509 		/* upon  successful spawn, re/set the proc control state */
4510 		if (imgp->ip_px_sa != NULL) {
4511 			switch (px_sa.psa_pcontrol) {
4512 			case POSIX_SPAWN_PCONTROL_THROTTLE:
4513 				p->p_pcaction = P_PCTHROTTLE;
4514 				break;
4515 			case POSIX_SPAWN_PCONTROL_SUSPEND:
4516 				p->p_pcaction = P_PCSUSP;
4517 				break;
4518 			case POSIX_SPAWN_PCONTROL_KILL:
4519 				p->p_pcaction = P_PCKILL;
4520 				break;
4521 			case POSIX_SPAWN_PCONTROL_NONE:
4522 			default:
4523 				p->p_pcaction = 0;
4524 				break;
4525 			}
4526 			;
4527 		}
4528 		exec_resettextvp(p, imgp);
4529 
4530 		/*
4531 		 * Enable new task IPC access if exec_activate_image() returned an
4532 		 * active task. (Checks active bit in ipc_task_enable() under lock).
4533 		 * Must enable after resettextvp so that task port policies are not evaluated
4534 		 * until the csblob in the textvp is accurately reflected.
4535 		 */
4536 		vm_map_setup(get_task_map(new_task), new_task);
4537 		ipc_task_enable(new_task);
4538 
4539 		/* Set task exception ports now that we can check entitlements */
4540 		if (imgp->ip_px_spa != NULL) {
4541 			error = exec_handle_exception_port_actions(imgp, &port_actions);
4542 		}
4543 
4544 #if CONFIG_MEMORYSTATUS
4545 		/* Set jetsam priority for DriverKit processes */
4546 		if (px_sa.psa_apptype == POSIX_SPAWN_PROC_TYPE_DRIVER) {
4547 			px_sa.psa_priority = JETSAM_PRIORITY_DRIVER_APPLE;
4548 		}
4549 
4550 		/* Has jetsam attributes? */
4551 		if (imgp->ip_px_sa != NULL && (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_SET)) {
4552 			int32_t memlimit_active = px_sa.psa_memlimit_active;
4553 			int32_t memlimit_inactive = px_sa.psa_memlimit_inactive;
4554 
4555 			memstat_priority_options_t priority_options = MEMSTAT_PRIORITY_OPTIONS_NONE;
4556 			if ((px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_USE_EFFECTIVE_PRIORITY)) {
4557 				priority_options |= MEMSTAT_PRIORITY_IS_EFFECTIVE;
4558 			}
4559 			memorystatus_set_priority(p, px_sa.psa_priority, 0,
4560 			    priority_options);
4561 
4562 			memlimit_options_t memlimit_options = MEMLIMIT_OPTIONS_NONE;
4563 			if ((px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_MEMLIMIT_ACTIVE_FATAL)) {
4564 				memlimit_options |= MEMLIMIT_ACTIVE_FATAL;
4565 			}
4566 			if ((px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_MEMLIMIT_INACTIVE_FATAL)) {
4567 				memlimit_options |= MEMLIMIT_INACTIVE_FATAL;
4568 			}
4569 			if (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_HIWATER_BACKGROUND) {
4570 				/*
4571 				 * With 2-level high-water-mark support,
4572 				 * POSIX_SPAWN_JETSAM_HIWATER_BACKGROUND is no longer relevant,
4573 				 * as background limits are described via the inactive limit
4574 				 * slots. However, if the
4575 				 * POSIX_SPAWN_JETSAM_HIWATER_BACKGROUND is passed in, we
4576 				 * attempt to mimic previous behavior by forcing the BG limit
4577 				 * data into the inactive/non-fatal mode and force the active
4578 				 * slots to hold system_wide/fatal mode.
4579 				 */
4580 				memlimit_options |= MEMLIMIT_ACTIVE_FATAL;
4581 				memlimit_options &= ~MEMLIMIT_INACTIVE_FATAL;
4582 				memlimit_active = -1;
4583 			}
4584 			memorystatus_set_memlimits(p, memlimit_active, memlimit_inactive,
4585 			    memlimit_options);
4586 		}
4587 
4588 		/* Has jetsam relaunch behavior? */
4589 		if (imgp->ip_px_sa != NULL && (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_RELAUNCH_BEHAVIOR_MASK)) {
4590 			/*
4591 			 * Launchd has passed in data indicating the behavior of this process in response to jetsam.
4592 			 * This data would be used by the jetsam subsystem to determine the position and protection
4593 			 * offered to this process on dirty -> clean transitions.
4594 			 */
4595 			int relaunch_flags = P_MEMSTAT_RELAUNCH_UNKNOWN;
4596 			switch (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_RELAUNCH_BEHAVIOR_MASK) {
4597 			case POSIX_SPAWN_JETSAM_RELAUNCH_BEHAVIOR_LOW:
4598 				relaunch_flags = P_MEMSTAT_RELAUNCH_LOW;
4599 				break;
4600 			case POSIX_SPAWN_JETSAM_RELAUNCH_BEHAVIOR_MED:
4601 				relaunch_flags = P_MEMSTAT_RELAUNCH_MED;
4602 				break;
4603 			case POSIX_SPAWN_JETSAM_RELAUNCH_BEHAVIOR_HIGH:
4604 				relaunch_flags = P_MEMSTAT_RELAUNCH_HIGH;
4605 				break;
4606 			default:
4607 				break;
4608 			}
4609 			memorystatus_relaunch_flags_update(p, relaunch_flags);
4610 		}
4611 
4612 #endif /* CONFIG_MEMORYSTATUS */
4613 		if (imgp->ip_px_sa != NULL && px_sa.psa_thread_limit > 0) {
4614 			task_set_thread_limit(new_task, (uint16_t)px_sa.psa_thread_limit);
4615 		}
4616 
4617 #if CONFIG_PROC_RESOURCE_LIMITS
4618 		if (imgp->ip_px_sa != NULL && (px_sa.psa_port_soft_limit > 0 || px_sa.psa_port_hard_limit > 0)) {
4619 			task_set_port_space_limits(new_task, (uint32_t)px_sa.psa_port_soft_limit,
4620 			    (uint32_t)px_sa.psa_port_hard_limit);
4621 		}
4622 
4623 		if (imgp->ip_px_sa != NULL && (px_sa.psa_filedesc_soft_limit > 0 || px_sa.psa_filedesc_hard_limit > 0)) {
4624 			proc_set_filedesc_limits(p, (int)px_sa.psa_filedesc_soft_limit,
4625 			    (int)px_sa.psa_filedesc_hard_limit);
4626 		}
4627 		if (imgp->ip_px_sa != NULL && (px_sa.psa_kqworkloop_soft_limit > 0 || px_sa.psa_kqworkloop_hard_limit > 0)) {
4628 			proc_set_kqworkloop_limits(p, (int)px_sa.psa_kqworkloop_soft_limit,
4629 			    (int)px_sa.psa_kqworkloop_hard_limit);
4630 		}
4631 #endif /* CONFIG_PROC_RESOURCE_LIMITS */
4632 	}
4633 
4634 
4635 	/*
4636 	 * If we successfully called fork1() or cloneproc, we always need
4637 	 * to do this. This is because we come back from that call with
4638 	 * signals blocked in the child, and we have to unblock them, for exec
4639 	 * case they are unblocked before activation, but for true spawn case
4640 	 * we want to wait until after we've performed any spawn actions.
4641 	 * This has to happen before process_signature(), which uses psignal.
4642 	 */
4643 	if (proc_transit_set) {
4644 		proc_transend(p, 0);
4645 	}
4646 
4647 	/*
4648 	 * Drop the signal lock on the child which was taken on our
4649 	 * behalf by forkproc()/cloneproc() to prevent signals being
4650 	 * received by the child in a partially constructed state.
4651 	 */
4652 	if (proc_signal_set) {
4653 		proc_signalend(p, 0);
4654 	}
4655 
4656 	if (error == 0) {
4657 		/*
4658 		 * We need to initialize the bank context behind the protection of
4659 		 * the proc_trans lock to prevent a race with exit. We can't do this during
4660 		 * exec_activate_image because task_bank_init checks entitlements that
4661 		 * aren't loaded until subsequent calls (including exec_resettextvp).
4662 		 */
4663 		error = proc_transstart(p, 0, 0);
4664 
4665 		if (error == 0) {
4666 			task_bank_init(new_task);
4667 			proc_transend(p, 0);
4668 		}
4669 
4670 #if __arm64__
4671 		proc_footprint_entitlement_hacks(p, new_task);
4672 #endif /* __arm64__ */
4673 
4674 #if XNU_TARGET_OS_OSX
4675 #define SINGLE_JIT_ENTITLEMENT "com.apple.security.cs.single-jit"
4676 		if (IOTaskHasEntitlement(new_task, SINGLE_JIT_ENTITLEMENT)) {
4677 			vm_map_single_jit(get_task_map(new_task));
4678 		}
4679 #endif /* XNU_TARGET_OS_OSX */
4680 
4681 #if __has_feature(ptrauth_calls)
4682 		task_set_pac_exception_fatal_flag(new_task);
4683 #endif /* __has_feature(ptrauth_calls) */
4684 		task_set_jit_flags(new_task);
4685 	}
4686 
4687 	/* Inherit task role from old task to new task for exec */
4688 	if (error == 0 && !spawn_no_exec) {
4689 		proc_inherit_task_role(new_task, old_task);
4690 	}
4691 
4692 #if CONFIG_ARCADE
4693 	if (error == 0) {
4694 		/*
4695 		 * Check to see if we need to trigger an arcade upcall AST now
4696 		 * that the vnode has been reset on the task.
4697 		 */
4698 		arcade_prepare(new_task, imgp->ip_new_thread);
4699 	}
4700 #endif /* CONFIG_ARCADE */
4701 
4702 	if (error == 0) {
4703 		proc_apply_jit_and_vm_policies(imgp, p, new_task);
4704 	}
4705 
4706 	/* Clear the initial wait on the thread before handling spawn policy */
4707 	if (imgp && imgp->ip_new_thread) {
4708 		task_clear_return_wait(get_threadtask(imgp->ip_new_thread), TCRW_CLEAR_INITIAL_WAIT);
4709 	}
4710 
4711 	/*
4712 	 * Apply the spawnattr policy, apptype (which primes the task for importance donation),
4713 	 * and bind any portwatch ports to the new task.
4714 	 * This must be done after the exec so that the child's thread is ready,
4715 	 * and after the in transit state has been released, because priority is
4716 	 * dropped here so we need to be prepared for a potentially long preemption interval
4717 	 *
4718 	 * TODO: Consider splitting this up into separate phases
4719 	 */
4720 	if (error == 0 && imgp->ip_px_sa != NULL) {
4721 		struct _posix_spawnattr *psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
4722 
4723 		error = exec_handle_spawnattr_policy(p, imgp->ip_new_thread, psa->psa_apptype, psa->psa_qos_clamp,
4724 		    psa->psa_darwin_role, &port_actions);
4725 	}
4726 
4727 	/* Transfer the turnstile watchport boost to new task if in exec */
4728 	if (error == 0 && !spawn_no_exec) {
4729 		task_transfer_turnstile_watchports(old_task, new_task, imgp->ip_new_thread);
4730 	}
4731 
4732 	if (error == 0 && imgp->ip_px_sa != NULL) {
4733 		struct _posix_spawnattr *psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
4734 
4735 		if (psa->psa_no_smt) {
4736 			task_set_no_smt(new_task);
4737 		}
4738 		if (psa->psa_tecs) {
4739 			task_set_tecs(new_task);
4740 		}
4741 	}
4742 
4743 	if (error == 0 && imgp->ip_px_sa != NULL) {
4744 		struct _posix_spawnattr *psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
4745 
4746 		if (psa->psa_options & PSA_OPTION_DATALESS_IOPOLICY) {
4747 			struct _iopol_param_t iop_param = {
4748 				.iop_scope = IOPOL_SCOPE_PROCESS,
4749 				.iop_iotype = IOPOL_TYPE_VFS_MATERIALIZE_DATALESS_FILES,
4750 				.iop_policy = psa->psa_dataless_iopolicy,
4751 			};
4752 			error = iopolicysys_vfs_materialize_dataless_files(p, IOPOL_CMD_SET, iop_param.iop_scope,
4753 			    iop_param.iop_policy, &iop_param);
4754 		}
4755 	}
4756 
4757 	if (error == 0) {
4758 		/* Apply the main thread qos */
4759 		thread_t main_thread = imgp->ip_new_thread;
4760 		task_set_main_thread_qos(new_task, main_thread);
4761 	}
4762 
4763 	/*
4764 	 * Release any ports we kept around for binding to the new task
4765 	 * We need to release the rights even if the posix_spawn has failed.
4766 	 */
4767 	if (imgp->ip_px_spa != NULL) {
4768 		exec_port_actions_destroy(&port_actions);
4769 	}
4770 
4771 	/*
4772 	 * We have to delay operations which might throw a signal until after
4773 	 * the signals have been unblocked; however, we want that to happen
4774 	 * after exec_resettextvp() so that the textvp is correct when they
4775 	 * fire.
4776 	 */
4777 	if (error == 0) {
4778 		error = process_signature(p, imgp);
4779 
4780 		/*
4781 		 * Pay for our earlier safety; deliver the delayed signals from
4782 		 * the incomplete spawn process now that it's complete.
4783 		 */
4784 		if (imgp != NULL && spawn_no_exec && (p->p_lflag & P_LTRACED)) {
4785 			psignal_vfork(p, proc_task(p), imgp->ip_new_thread, SIGTRAP);
4786 		}
4787 
4788 		if (error == 0 && !spawn_no_exec) {
4789 			extern uint64_t kdp_task_exec_meta_flags(task_t task);
4790 			KDBG(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXEC),
4791 			    proc_getpid(p), kdp_task_exec_meta_flags(proc_task(p)));
4792 		}
4793 	}
4794 
4795 	if (spawn_no_exec) {
4796 		/* flag the 'fork' has occurred */
4797 		proc_knote(p->p_pptr, NOTE_FORK | proc_getpid(p));
4798 	}
4799 
4800 	/* flag exec has occurred, notify only if it has not failed due to FP Key error */
4801 	if (!error && ((p->p_lflag & P_LTERM_DECRYPTFAIL) == 0)) {
4802 		proc_knote(p, NOTE_EXEC);
4803 	}
4804 
4805 	if (imgp != NULL) {
4806 		uthread_set_exec_data(current_uthread(), NULL);
4807 		if (imgp->ip_vp) {
4808 			vnode_put(imgp->ip_vp);
4809 		}
4810 		if (imgp->ip_scriptvp) {
4811 			vnode_put(imgp->ip_scriptvp);
4812 		}
4813 		if (imgp->ip_strings) {
4814 			execargs_free(imgp);
4815 		}
4816 		if (imgp->ip_free_map) {
4817 			/* Free the map after dropping iocount on vnode to avoid deadlock */
4818 			vm_map_deallocate(imgp->ip_free_map);
4819 		}
4820 		kfree_data(imgp->ip_px_sfa,
4821 		    px_args.file_actions_size);
4822 		kfree_data(imgp->ip_px_spa,
4823 		    px_args.port_actions_size);
4824 #if CONFIG_PERSONAS
4825 		kfree_data(imgp->ip_px_persona,
4826 		    px_args.persona_info_size);
4827 #endif
4828 		kfree_data(imgp->ip_px_pcred_info,
4829 		    px_args.posix_cred_info_size);
4830 
4831 		if (subsystem_root_path != NULL) {
4832 			zfree(ZV_NAMEI, subsystem_root_path);
4833 		}
4834 #if CONFIG_MACF
4835 		struct ip_px_smpx_s *px_s = &imgp->ip_px_smpx;
4836 		kfree_data(px_s->array, px_args.mac_extensions_size);
4837 		kfree_data(px_s->data, (vm_size_t)px_s->datalen);
4838 
4839 		if (imgp->ip_execlabelp) {
4840 			mac_cred_label_free(imgp->ip_execlabelp);
4841 			imgp->ip_execlabelp = NULL;
4842 		}
4843 		if (imgp->ip_scriptlabelp) {
4844 			mac_vnode_label_free(imgp->ip_scriptlabelp);
4845 			imgp->ip_scriptlabelp = NULL;
4846 		}
4847 		if (imgp->ip_cs_error != OS_REASON_NULL) {
4848 			os_reason_free(imgp->ip_cs_error);
4849 			imgp->ip_cs_error = OS_REASON_NULL;
4850 		}
4851 		if (imgp->ip_inherited_shared_region_id != NULL) {
4852 			kfree_data(imgp->ip_inherited_shared_region_id,
4853 			    strlen(imgp->ip_inherited_shared_region_id) + 1);
4854 			imgp->ip_inherited_shared_region_id = NULL;
4855 		}
4856 #endif
4857 	}
4858 
4859 #if CONFIG_DTRACE
4860 	if (spawn_no_exec) {
4861 		/*
4862 		 * In the original DTrace reference implementation,
4863 		 * posix_spawn() was a libc routine that just
4864 		 * did vfork(2) then exec(2).  Thus the proc::: probes
4865 		 * are very fork/exec oriented.  The details of this
4866 		 * in-kernel implementation of posix_spawn() is different
4867 		 * (while producing the same process-observable effects)
4868 		 * particularly w.r.t. errors, and which thread/process
4869 		 * is constructing what on behalf of whom.
4870 		 */
4871 		if (error) {
4872 			DTRACE_PROC1(spawn__failure, int, error);
4873 		} else {
4874 			DTRACE_PROC(spawn__success);
4875 			/*
4876 			 * Some DTrace scripts, e.g. newproc.d in
4877 			 * /usr/bin, rely on the the 'exec-success'
4878 			 * probe being fired in the child after the
4879 			 * new process image has been constructed
4880 			 * in order to determine the associated pid.
4881 			 *
4882 			 * So, even though the parent built the image
4883 			 * here, for compatibility, mark the new thread
4884 			 * so 'exec-success' fires on it as it leaves
4885 			 * the kernel.
4886 			 */
4887 			dtrace_thread_didexec(imgp->ip_new_thread);
4888 		}
4889 	} else {
4890 		if (error) {
4891 			DTRACE_PROC1(exec__failure, int, error);
4892 		} else {
4893 			dtrace_thread_didexec(imgp->ip_new_thread);
4894 		}
4895 	}
4896 
4897 	if ((dtrace_proc_waitfor_hook = dtrace_proc_waitfor_exec_ptr) != NULL) {
4898 		(*dtrace_proc_waitfor_hook)(p);
4899 	}
4900 #endif
4901 
4902 #if CONFIG_AUDIT
4903 	if (!error && AUDIT_ENABLED() && p) {
4904 		/* Add the CDHash of the new process to the audit record */
4905 		uint8_t *cdhash = cs_get_cdhash(p);
4906 		if (cdhash) {
4907 			AUDIT_ARG(data, cdhash, sizeof(uint8_t), CS_CDHASH_LEN);
4908 		}
4909 	}
4910 #endif
4911 
4912 	/* terminate the new task if exec failed  */
4913 	if (new_task != NULL && task_is_exec_copy(new_task)) {
4914 		task_terminate_internal(new_task);
4915 	}
4916 
4917 	if (exec_failure_reason && !spawn_no_exec) {
4918 		psignal_with_reason(p, SIGKILL, exec_failure_reason);
4919 		exec_failure_reason = NULL;
4920 	}
4921 
4922 	/* Return to both the parent and the child? */
4923 	if (imgp != NULL && spawn_no_exec) {
4924 		/*
4925 		 * If the parent wants the pid, copy it out
4926 		 */
4927 		if (error == 0 && pid != USER_ADDR_NULL) {
4928 			_Static_assert(sizeof(pid_t) == 4, "posix_spawn() assumes a 32-bit pid_t");
4929 			bool aligned = (pid & 3) == 0;
4930 			if (aligned) {
4931 				(void)copyout_atomic32(proc_getpid(p), pid);
4932 			} else {
4933 				(void)suword(pid, proc_getpid(p));
4934 			}
4935 		}
4936 		retval[0] = error;
4937 
4938 		/*
4939 		 * If we had an error, perform an internal reap ; this is
4940 		 * entirely safe, as we have a real process backing us.
4941 		 */
4942 		if (error) {
4943 			proc_list_lock();
4944 			p->p_listflag |= P_LIST_DEADPARENT;
4945 			proc_list_unlock();
4946 			proc_lock(p);
4947 			/* make sure no one else has killed it off... */
4948 			if (p->p_stat != SZOMB && p->exit_thread == NULL) {
4949 				p->exit_thread = current_thread();
4950 				p->p_posix_spawn_failed = true;
4951 				proc_unlock(p);
4952 				exit1(p, 1, (int *)NULL);
4953 			} else {
4954 				/* someone is doing it for us; just skip it */
4955 				proc_unlock(p);
4956 			}
4957 		}
4958 	}
4959 
4960 	/*
4961 	 * Do not terminate the current task, if proc_exec_switch_task did not
4962 	 * switch the tasks, terminating the current task without the switch would
4963 	 * result in loosing the SIGKILL status.
4964 	 */
4965 	if (task_did_exec(old_task)) {
4966 		/* Terminate the current task, since exec will start in new task */
4967 		task_terminate_internal(old_task);
4968 	}
4969 
4970 	/* Release the thread ref returned by cloneproc/fork1 */
4971 	if (imgp != NULL && imgp->ip_new_thread) {
4972 		/* clear the exec complete flag if there is an error before point of no-return */
4973 		uint32_t clearwait_flags = TCRW_CLEAR_FINAL_WAIT;
4974 		if (!spawn_no_exec && !exec_done && error != 0) {
4975 			clearwait_flags |= TCRW_CLEAR_EXEC_COMPLETE;
4976 		}
4977 		/* wake up the new thread */
4978 		task_clear_return_wait(get_threadtask(imgp->ip_new_thread), clearwait_flags);
4979 		thread_deallocate(imgp->ip_new_thread);
4980 		imgp->ip_new_thread = NULL;
4981 	}
4982 
4983 	/* Release the ref returned by cloneproc/fork1 */
4984 	if (new_task) {
4985 		task_deallocate(new_task);
4986 		new_task = NULL;
4987 	}
4988 
4989 	if (should_release_proc_ref) {
4990 		proc_rele(p);
4991 	}
4992 
4993 	kfree_type(typeof(*__spawn_data), __spawn_data);
4994 
4995 	if (inherit != NULL) {
4996 		ipc_importance_release(inherit);
4997 	}
4998 
4999 #if CONFIG_EXCLAVES
5000 	if (task_conclave_id != NULL) {
5001 		kfree_data(task_conclave_id, MAXCONCLAVENAME);
5002 	}
5003 #endif
5004 
5005 	assert(spawn_no_exec || exec_failure_reason == NULL);
5006 	return error;
5007 }
5008 
5009 /*
5010  * proc_exec_switch_task
5011  *
5012  * Parameters:  old_proc		proc before exec
5013  *		new_proc		proc after exec
5014  *		old_task		task before exec
5015  *		new_task		task after exec
5016  *		imgp			image params
5017  *		inherit			resulting importance linkage
5018  *
5019  * Returns: proc.
5020  *
5021  * Note: The function will switch proc in pid hash from old proc to new proc.
5022  * The switch needs to happen after draining all proc refs and inside
5023  * a proc list lock. In the case of failure to switch the proc, which
5024  * might happen if the process received a SIGKILL or jetsam killed it,
5025  * it will make sure that the new tasks terminates. User proc ref returned
5026  * to caller.
5027  *
5028  * This function is called after point of no return, in the case
5029  * failure to switch, it will terminate the new task and swallow the
5030  * error and let the terminated process complete exec and die.
5031  */
5032 proc_t
proc_exec_switch_task(proc_t old_proc,proc_t new_proc,task_t old_task,task_t new_task,struct image_params * imgp,void ** inherit)5033 proc_exec_switch_task(proc_t old_proc, proc_t new_proc, task_t old_task, task_t new_task, struct image_params *imgp, void **inherit)
5034 {
5035 	boolean_t task_active;
5036 	boolean_t proc_active;
5037 	boolean_t thread_active;
5038 	boolean_t reparent_traced_child = FALSE;
5039 	thread_t old_thread = current_thread();
5040 	thread_t new_thread = imgp->ip_new_thread;
5041 
5042 	thread_set_exec_promotion(old_thread);
5043 	old_proc = proc_refdrain_will_exec(old_proc);
5044 
5045 	new_proc = proc_refdrain_will_exec(new_proc);
5046 	/* extra proc ref returned to the caller */
5047 
5048 	assert(get_threadtask(new_thread) == new_task);
5049 	task_active = task_is_active(new_task);
5050 	proc_active = !(old_proc->p_lflag & P_LEXIT);
5051 
5052 	/* Check if the current thread is not aborted due to SIGKILL */
5053 	thread_active = thread_is_active(old_thread);
5054 
5055 	/*
5056 	 * Do not switch the proc if the new task or proc is already terminated
5057 	 * as a result of error in exec past point of no return
5058 	 */
5059 	if (proc_active && task_active && thread_active) {
5060 		uthread_t new_uthread = get_bsdthread_info(new_thread);
5061 		uthread_t old_uthread = current_uthread();
5062 
5063 		/* Clear dispatchqueue and workloop ast offset */
5064 		new_proc->p_dispatchqueue_offset = 0;
5065 		new_proc->p_dispatchqueue_serialno_offset = 0;
5066 		new_proc->p_dispatchqueue_label_offset = 0;
5067 		new_proc->p_return_to_kernel_offset = 0;
5068 		new_proc->p_pthread_wq_quantum_offset = 0;
5069 
5070 		/* If old_proc is session leader, change the leader to new proc */
5071 		session_replace_leader(old_proc, new_proc);
5072 
5073 		proc_lock(old_proc);
5074 
5075 		/* Copy the signal state, dtrace state and set bsd ast on new thread */
5076 		act_set_astbsd(new_thread);
5077 		new_uthread->uu_siglist |= old_uthread->uu_siglist;
5078 		new_uthread->uu_siglist |= old_proc->p_siglist;
5079 		new_uthread->uu_sigwait = old_uthread->uu_sigwait;
5080 		new_uthread->uu_sigmask = old_uthread->uu_sigmask;
5081 		new_uthread->uu_oldmask = old_uthread->uu_oldmask;
5082 		new_uthread->uu_exit_reason = old_uthread->uu_exit_reason;
5083 #if CONFIG_DTRACE
5084 		new_uthread->t_dtrace_sig = old_uthread->t_dtrace_sig;
5085 		new_uthread->t_dtrace_stop = old_uthread->t_dtrace_stop;
5086 		new_uthread->t_dtrace_resumepid = old_uthread->t_dtrace_resumepid;
5087 		assert(new_uthread->t_dtrace_scratch == NULL);
5088 		new_uthread->t_dtrace_scratch = old_uthread->t_dtrace_scratch;
5089 
5090 		old_uthread->t_dtrace_sig = 0;
5091 		old_uthread->t_dtrace_stop = 0;
5092 		old_uthread->t_dtrace_resumepid = 0;
5093 		old_uthread->t_dtrace_scratch = NULL;
5094 #endif
5095 
5096 #if CONFIG_PROC_UDATA_STORAGE
5097 		new_proc->p_user_data = old_proc->p_user_data;
5098 #endif /* CONFIG_PROC_UDATA_STORAGE */
5099 
5100 		/* Copy the resource accounting info */
5101 		thread_copy_resource_info(new_thread, current_thread());
5102 
5103 		/* Clear the exit reason and signal state on old thread */
5104 		old_uthread->uu_exit_reason = NULL;
5105 		old_uthread->uu_siglist = 0;
5106 
5107 		task_set_did_exec_flag(old_task);
5108 		task_clear_exec_copy_flag(new_task);
5109 
5110 		task_copy_fields_for_exec(new_task, old_task);
5111 
5112 		/*
5113 		 * Need to transfer pending watch port boosts to the new task
5114 		 * while still making sure that the old task remains in the
5115 		 * importance linkage. Create an importance linkage from old task
5116 		 * to new task, then switch the task importance base of old task
5117 		 * and new task. After the switch the port watch boost will be
5118 		 * boosting the new task and new task will be donating importance
5119 		 * to old task.
5120 		 */
5121 		*inherit = ipc_importance_exec_switch_task(old_task, new_task);
5122 
5123 		/* Transfer parent's ptrace state to child */
5124 		new_proc->p_lflag &= ~(P_LTRACED | P_LSIGEXC | P_LNOATTACH);
5125 		new_proc->p_lflag |= (old_proc->p_lflag & (P_LTRACED | P_LSIGEXC | P_LNOATTACH));
5126 		new_proc->p_oppid = old_proc->p_oppid;
5127 
5128 		if (old_proc->p_pptr != new_proc->p_pptr) {
5129 			reparent_traced_child = TRUE;
5130 			new_proc->p_lflag |= P_LTRACE_WAIT;
5131 		}
5132 
5133 		proc_unlock(old_proc);
5134 
5135 		/* Update the list of proc knotes */
5136 		proc_transfer_knotes(old_proc, new_proc);
5137 
5138 		/* Update the proc interval timers */
5139 		proc_inherit_itimers(old_proc, new_proc);
5140 
5141 		proc_list_lock();
5142 
5143 		/* Insert the new proc in child list of parent proc */
5144 		p_reparentallchildren(old_proc, new_proc);
5145 
5146 		/* Switch proc in pid hash */
5147 		phash_replace_locked(old_proc, new_proc);
5148 
5149 		/* Transfer the shadow flag to old proc */
5150 		os_atomic_andnot(&new_proc->p_refcount, P_REF_SHADOW, relaxed);
5151 		os_atomic_or(&old_proc->p_refcount, P_REF_SHADOW, relaxed);
5152 
5153 		/* Change init proc if launchd exec */
5154 		if (old_proc == initproc) {
5155 			/* Take the ref on new proc after proc_refwake_did_exec */
5156 			initproc = new_proc;
5157 			/* Drop the proc ref on old proc */
5158 			proc_rele(old_proc);
5159 		}
5160 
5161 		proc_list_unlock();
5162 #if CONFIG_EXCLAVES
5163 		if (task_inherit_conclave(old_task, new_task, imgp->ip_vp,
5164 		    (int64_t)imgp->ip_arch_offset) != KERN_SUCCESS) {
5165 			task_terminate_internal(new_task);
5166 		}
5167 #endif
5168 	} else {
5169 		task_terminate_internal(new_task);
5170 	}
5171 
5172 	proc_refwake_did_exec(new_proc);
5173 	proc_refwake_did_exec(old_proc);
5174 
5175 	/* Take a ref on initproc if it changed */
5176 	if (new_proc == initproc) {
5177 		initproc = proc_ref(new_proc, false);
5178 		assert(initproc != PROC_NULL);
5179 	}
5180 
5181 	thread_clear_exec_promotion(old_thread);
5182 	proc_rele(old_proc);
5183 
5184 	if (reparent_traced_child) {
5185 		proc_t pp = proc_parent(old_proc);
5186 		assert(pp != PROC_NULL);
5187 
5188 		proc_reparentlocked(new_proc, pp, 1, 0);
5189 		proc_rele(pp);
5190 
5191 		proc_lock(new_proc);
5192 		new_proc->p_lflag &= ~P_LTRACE_WAIT;
5193 		proc_unlock(new_proc);
5194 	}
5195 
5196 	return new_proc;
5197 }
5198 
5199 /*
5200  * execve
5201  *
5202  * Parameters:	uap->fname		File name to exec
5203  *		uap->argp		Argument list
5204  *		uap->envp		Environment list
5205  *
5206  * Returns:	0			Success
5207  *	__mac_execve:EINVAL		Invalid argument
5208  *	__mac_execve:ENOTSUP		Invalid argument
5209  *	__mac_execve:EACCES		Permission denied
5210  *	__mac_execve:EINTR		Interrupted function
5211  *	__mac_execve:ENOMEM		Not enough space
5212  *	__mac_execve:EFAULT		Bad address
5213  *	__mac_execve:ENAMETOOLONG	Filename too long
5214  *	__mac_execve:ENOEXEC		Executable file format error
5215  *	__mac_execve:ETXTBSY		Text file busy [misuse of error code]
5216  *	__mac_execve:???
5217  *
5218  * TODO:	Dynamic linker header address on stack is copied via suword()
5219  */
5220 /* ARGSUSED */
5221 int
execve(proc_t p,struct execve_args * uap,int32_t * retval)5222 execve(proc_t p, struct execve_args *uap, int32_t *retval)
5223 {
5224 	struct __mac_execve_args muap;
5225 	int err;
5226 
5227 	memoryshot(DBG_VM_EXECVE, DBG_FUNC_NONE);
5228 
5229 	muap.fname = uap->fname;
5230 	muap.argp = uap->argp;
5231 	muap.envp = uap->envp;
5232 	muap.mac_p = USER_ADDR_NULL;
5233 	err = __mac_execve(p, &muap, retval);
5234 
5235 	return err;
5236 }
5237 
5238 /*
5239  * __mac_execve
5240  *
5241  * Parameters:	uap->fname		File name to exec
5242  *		uap->argp		Argument list
5243  *		uap->envp		Environment list
5244  *		uap->mac_p		MAC label supplied by caller
5245  *
5246  * Returns:	0			Success
5247  *		EINVAL			Invalid argument
5248  *		ENOTSUP			Not supported
5249  *		ENOEXEC			Executable file format error
5250  *	exec_activate_image:EINVAL	Invalid argument
5251  *	exec_activate_image:EACCES	Permission denied
5252  *	exec_activate_image:EINTR	Interrupted function
5253  *	exec_activate_image:ENOMEM	Not enough space
5254  *	exec_activate_image:EFAULT	Bad address
5255  *	exec_activate_image:ENAMETOOLONG	Filename too long
5256  *	exec_activate_image:ENOEXEC	Executable file format error
5257  *	exec_activate_image:ETXTBSY	Text file busy [misuse of error code]
5258  *	exec_activate_image:EBADEXEC	The executable is corrupt/unknown
5259  *	exec_activate_image:???
5260  *	mac_execve_enter:???
5261  *
5262  * TODO:	Dynamic linker header address on stack is copied via suword()
5263  */
5264 int
__mac_execve(proc_t p,struct __mac_execve_args * uap,int32_t * retval __unused)5265 __mac_execve(proc_t p, struct __mac_execve_args *uap, int32_t *retval __unused)
5266 {
5267 	struct image_params *imgp = NULL;
5268 	struct vnode_attr *vap = NULL;
5269 	struct vnode_attr *origvap = NULL;
5270 	int error;
5271 	int is_64 = IS_64BIT_PROCESS(p);
5272 	struct vfs_context context;
5273 	struct uthread  *uthread = NULL;
5274 	task_t old_task = current_task();
5275 	task_t new_task = NULL;
5276 	boolean_t should_release_proc_ref = FALSE;
5277 	boolean_t exec_done = FALSE;
5278 	void *inherit = NULL;
5279 	struct {
5280 		struct image_params imgp;
5281 		struct vnode_attr va;
5282 		struct vnode_attr origva;
5283 	} *__execve_data;
5284 
5285 	/* Allocate a big chunk for locals instead of using stack since these
5286 	 * structures are pretty big.
5287 	 */
5288 	__execve_data = kalloc_type(typeof(*__execve_data), Z_WAITOK | Z_ZERO);
5289 	if (__execve_data == NULL) {
5290 		error = ENOMEM;
5291 		goto exit_with_error;
5292 	}
5293 	imgp = &__execve_data->imgp;
5294 	vap = &__execve_data->va;
5295 	origvap = &__execve_data->origva;
5296 
5297 	/* Initialize the common data in the image_params structure */
5298 	imgp->ip_user_fname = uap->fname;
5299 	imgp->ip_user_argv = uap->argp;
5300 	imgp->ip_user_envv = uap->envp;
5301 	imgp->ip_vattr = vap;
5302 	imgp->ip_origvattr = origvap;
5303 	imgp->ip_vfs_context = &context;
5304 	imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT_ADDR : IMGPF_NONE) | ((p->p_flag & P_DISABLE_ASLR) ? IMGPF_DISABLE_ASLR : IMGPF_NONE);
5305 	imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32);
5306 	imgp->ip_mac_return = 0;
5307 	imgp->ip_cs_error = OS_REASON_NULL;
5308 	imgp->ip_simulator_binary = IMGPF_SB_DEFAULT;
5309 	imgp->ip_subsystem_root_path = NULL;
5310 	uthread_set_exec_data(current_uthread(), imgp);
5311 
5312 #if CONFIG_MACF
5313 	if (uap->mac_p != USER_ADDR_NULL) {
5314 		error = mac_execve_enter(uap->mac_p, imgp);
5315 		if (error) {
5316 			goto exit_with_error;
5317 		}
5318 	}
5319 #endif
5320 	uthread = current_uthread();
5321 	{
5322 		imgp->ip_flags |= IMGPF_EXEC;
5323 
5324 		/* Adjust the user proc count */
5325 		(void)chgproccnt(kauth_getruid(), 1);
5326 		/*
5327 		 * For execve case, create a new proc, task and thread
5328 		 * but don't make the proc visible to userland. After
5329 		 * image activation, the new proc would take place of
5330 		 * the old proc in pid hash and other lists that make
5331 		 * the proc visible to the system.
5332 		 */
5333 		imgp->ip_new_thread = cloneproc(old_task, NULL, p, CLONEPROC_EXEC);
5334 		/* task and thread ref returned by cloneproc */
5335 		if (imgp->ip_new_thread == NULL) {
5336 			(void)chgproccnt(kauth_getruid(), -1);
5337 			error = ENOMEM;
5338 			goto exit_with_error;
5339 		}
5340 
5341 		new_task = get_threadtask(imgp->ip_new_thread);
5342 	}
5343 
5344 
5345 	p = (proc_t)get_bsdthreadtask_info(imgp->ip_new_thread);
5346 
5347 	context.vc_thread = imgp->ip_new_thread;
5348 	context.vc_ucred = kauth_cred_proc_ref(p);      /* XXX must NOT be kauth_cred_get() */
5349 
5350 	imgp->ip_subsystem_root_path = p->p_subsystem_root_path;
5351 
5352 	proc_transend(p, 0);
5353 	proc_signalend(p, 0);
5354 
5355 	/*
5356 	 * Activate the image.
5357 	 * Warning: If activation failed after point of no return, it returns error
5358 	 * as 0 and pretends the call succeeded.
5359 	 */
5360 	error = exec_activate_image(imgp);
5361 	/* thread and task ref returned for vfexec case */
5362 
5363 	if (imgp->ip_new_thread != NULL) {
5364 		/*
5365 		 * task reference might be returned by exec_activate_image
5366 		 * for vfexec.
5367 		 */
5368 		new_task = get_threadtask(imgp->ip_new_thread);
5369 #if defined(HAS_APPLE_PAC)
5370 		ml_task_set_disable_user_jop(new_task, imgp->ip_flags & IMGPF_NOJOP ? TRUE : FALSE);
5371 		ml_thread_set_disable_user_jop(imgp->ip_new_thread, imgp->ip_flags & IMGPF_NOJOP ? TRUE : FALSE);
5372 #endif
5373 	}
5374 
5375 	if (!error) {
5376 		p = proc_exec_switch_task(current_proc(), p, old_task, new_task, imgp, &inherit);
5377 		/* proc ref returned */
5378 		should_release_proc_ref = TRUE;
5379 	}
5380 
5381 	kauth_cred_unref(&context.vc_ucred);
5382 
5383 	if (!error) {
5384 		exec_done = TRUE;
5385 		assert(imgp->ip_new_thread != NULL);
5386 
5387 		exec_resettextvp(p, imgp);
5388 		/*
5389 		 * Enable new task IPC access if exec_activate_image() returned an
5390 		 * active task. (Checks active bit in ipc_task_enable() under lock).
5391 		 * Must enable after resettextvp so that task port policies are not evaluated
5392 		 * until the csblob in the textvp is accurately reflected.
5393 		 */
5394 		vm_map_setup(get_task_map(new_task), new_task);
5395 		ipc_task_enable(new_task);
5396 		error = process_signature(p, imgp);
5397 	}
5398 
5399 #if defined(HAS_APPLE_PAC)
5400 	if (imgp->ip_new_thread && !error) {
5401 		ml_task_set_jop_pid_from_shared_region(new_task, imgp->ip_flags & IMGPF_NOJOP);
5402 		ml_thread_set_jop_pid(imgp->ip_new_thread, new_task);
5403 	}
5404 #endif /* defined(HAS_APPLE_PAC) */
5405 
5406 	/* flag exec has occurred, notify only if it has not failed due to FP Key error */
5407 	if (exec_done && ((p->p_lflag & P_LTERM_DECRYPTFAIL) == 0)) {
5408 		proc_knote(p, NOTE_EXEC);
5409 	}
5410 
5411 	if (imgp->ip_vp != NULLVP) {
5412 		vnode_put(imgp->ip_vp);
5413 	}
5414 	if (imgp->ip_scriptvp != NULLVP) {
5415 		vnode_put(imgp->ip_scriptvp);
5416 	}
5417 	if (imgp->ip_free_map) {
5418 		/* Free the map after dropping iocount on vnode to avoid deadlock */
5419 		vm_map_deallocate(imgp->ip_free_map);
5420 	}
5421 	if (imgp->ip_strings) {
5422 		execargs_free(imgp);
5423 	}
5424 #if CONFIG_MACF
5425 	if (imgp->ip_execlabelp) {
5426 		mac_cred_label_free(imgp->ip_execlabelp);
5427 		imgp->ip_execlabelp = NULL;
5428 	}
5429 	if (imgp->ip_scriptlabelp) {
5430 		mac_vnode_label_free(imgp->ip_scriptlabelp);
5431 		imgp->ip_scriptlabelp = NULL;
5432 	}
5433 #endif
5434 	if (imgp->ip_cs_error != OS_REASON_NULL) {
5435 		os_reason_free(imgp->ip_cs_error);
5436 		imgp->ip_cs_error = OS_REASON_NULL;
5437 	}
5438 
5439 	if (!error) {
5440 		/*
5441 		 * We need to initialize the bank context behind the protection of
5442 		 * the proc_trans lock to prevent a race with exit. We can't do this during
5443 		 * exec_activate_image because task_bank_init checks entitlements that
5444 		 * aren't loaded until subsequent calls (including exec_resettextvp).
5445 		 */
5446 		error = proc_transstart(p, 0, 0);
5447 	}
5448 
5449 	if (!error) {
5450 		task_bank_init(new_task);
5451 		proc_transend(p, 0);
5452 
5453 		// Don't inherit crash behavior across exec, but preserve crash behavior from bootargs
5454 		p->p_crash_behavior = 0;
5455 		p->p_crash_behavior_deadline = 0;
5456 #if (DEVELOPMENT || DEBUG)
5457 		set_crash_behavior_from_bootarg(p);
5458 #endif
5459 
5460 #if __arm64__
5461 		proc_footprint_entitlement_hacks(p, new_task);
5462 #endif /* __arm64__ */
5463 
5464 #if XNU_TARGET_OS_OSX
5465 		if (IOTaskHasEntitlement(new_task, SINGLE_JIT_ENTITLEMENT)) {
5466 			vm_map_single_jit(get_task_map(new_task));
5467 		}
5468 #endif /* XNU_TARGET_OS_OSX */
5469 
5470 		/* Sever any extant thread affinity */
5471 		thread_affinity_exec(current_thread());
5472 
5473 		/* Inherit task role from old task to new task for exec */
5474 		proc_inherit_task_role(new_task, old_task);
5475 
5476 		thread_t main_thread = imgp->ip_new_thread;
5477 
5478 		task_set_main_thread_qos(new_task, main_thread);
5479 
5480 #if __has_feature(ptrauth_calls)
5481 		task_set_pac_exception_fatal_flag(new_task);
5482 #endif /* __has_feature(ptrauth_calls) */
5483 		task_set_jit_flags(new_task);
5484 
5485 #if CONFIG_ARCADE
5486 		/*
5487 		 * Check to see if we need to trigger an arcade upcall AST now
5488 		 * that the vnode has been reset on the task.
5489 		 */
5490 		arcade_prepare(new_task, imgp->ip_new_thread);
5491 #endif /* CONFIG_ARCADE */
5492 
5493 		proc_apply_jit_and_vm_policies(imgp, p, new_task);
5494 
5495 		if (vm_darkwake_mode == TRUE) {
5496 			/*
5497 			 * This process is being launched when the system
5498 			 * is in darkwake. So mark it specially. This will
5499 			 * cause all its pages to be entered in the background Q.
5500 			 */
5501 			task_set_darkwake_mode(new_task, vm_darkwake_mode);
5502 		}
5503 
5504 #if CONFIG_DTRACE
5505 		dtrace_thread_didexec(imgp->ip_new_thread);
5506 
5507 		if ((dtrace_proc_waitfor_hook = dtrace_proc_waitfor_exec_ptr) != NULL) {
5508 			(*dtrace_proc_waitfor_hook)(p);
5509 		}
5510 #endif
5511 
5512 #if CONFIG_AUDIT
5513 		if (!error && AUDIT_ENABLED() && p) {
5514 			/* Add the CDHash of the new process to the audit record */
5515 			uint8_t *cdhash = cs_get_cdhash(p);
5516 			if (cdhash) {
5517 				AUDIT_ARG(data, cdhash, sizeof(uint8_t), CS_CDHASH_LEN);
5518 			}
5519 		}
5520 #endif
5521 	} else {
5522 		DTRACE_PROC1(exec__failure, int, error);
5523 	}
5524 
5525 exit_with_error:
5526 
5527 	/* terminate the new task it if exec failed  */
5528 	if (new_task != NULL && task_is_exec_copy(new_task)) {
5529 		task_terminate_internal(new_task);
5530 	}
5531 
5532 	if (imgp != NULL) {
5533 		/* Clear the initial wait on the thread transferring watchports */
5534 		if (imgp->ip_new_thread) {
5535 			task_clear_return_wait(get_threadtask(imgp->ip_new_thread), TCRW_CLEAR_INITIAL_WAIT);
5536 		}
5537 
5538 		/* Transfer the watchport boost to new task */
5539 		if (!error) {
5540 			task_transfer_turnstile_watchports(old_task,
5541 			    new_task, imgp->ip_new_thread);
5542 		}
5543 		/*
5544 		 * Do not terminate the current task, if proc_exec_switch_task did not
5545 		 * switch the tasks, terminating the current task without the switch would
5546 		 * result in loosing the SIGKILL status.
5547 		 */
5548 		if (task_did_exec(old_task)) {
5549 			/* Terminate the current task, since exec will start in new task */
5550 			task_terminate_internal(old_task);
5551 		}
5552 
5553 		/* Release the thread ref returned by cloneproc */
5554 		if (imgp->ip_new_thread) {
5555 			/* clear the exec complete flag if there is an error before point of no-return */
5556 			uint32_t clearwait_flags = TCRW_CLEAR_FINAL_WAIT;
5557 			if (!exec_done && error != 0) {
5558 				clearwait_flags |= TCRW_CLEAR_EXEC_COMPLETE;
5559 			}
5560 			/* wake up the new exec thread */
5561 			task_clear_return_wait(get_threadtask(imgp->ip_new_thread), clearwait_flags);
5562 			thread_deallocate(imgp->ip_new_thread);
5563 			imgp->ip_new_thread = NULL;
5564 		}
5565 	}
5566 
5567 	/* Release the ref returned by fork_create_child */
5568 	if (new_task) {
5569 		task_deallocate(new_task);
5570 		new_task = NULL;
5571 	}
5572 
5573 	if (should_release_proc_ref) {
5574 		proc_rele(p);
5575 	}
5576 
5577 	uthread_set_exec_data(current_uthread(), NULL);
5578 	kfree_type(typeof(*__execve_data), __execve_data);
5579 
5580 	if (inherit != NULL) {
5581 		ipc_importance_release(inherit);
5582 	}
5583 
5584 	return error;
5585 }
5586 
5587 
5588 /*
5589  * copyinptr
5590  *
5591  * Description:	Copy a pointer in from user space to a user_addr_t in kernel
5592  *		space, based on 32/64 bitness of the user space
5593  *
5594  * Parameters:	froma			User space address
5595  *		toptr			Address of kernel space user_addr_t
5596  *		ptr_size		4/8, based on 'froma' address space
5597  *
5598  * Returns:	0			Success
5599  *		EFAULT			Bad 'froma'
5600  *
5601  * Implicit returns:
5602  *		*ptr_size		Modified
5603  */
5604 static int
copyinptr(user_addr_t froma,user_addr_t * toptr,int ptr_size)5605 copyinptr(user_addr_t froma, user_addr_t *toptr, int ptr_size)
5606 {
5607 	int error;
5608 
5609 	if (ptr_size == 4) {
5610 		/* 64 bit value containing 32 bit address */
5611 		unsigned int i = 0;
5612 
5613 		error = copyin(froma, &i, 4);
5614 		*toptr = CAST_USER_ADDR_T(i);   /* SAFE */
5615 	} else {
5616 		error = copyin(froma, toptr, 8);
5617 	}
5618 	return error;
5619 }
5620 
5621 
5622 /*
5623  * copyoutptr
5624  *
5625  * Description:	Copy a pointer out from a user_addr_t in kernel space to
5626  *		user space, based on 32/64 bitness of the user space
5627  *
5628  * Parameters:	ua			User space address to copy to
5629  *		ptr			Address of kernel space user_addr_t
5630  *		ptr_size		4/8, based on 'ua' address space
5631  *
5632  * Returns:	0			Success
5633  *		EFAULT			Bad 'ua'
5634  *
5635  */
5636 static int
copyoutptr(user_addr_t ua,user_addr_t ptr,int ptr_size)5637 copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size)
5638 {
5639 	int error;
5640 
5641 	if (ptr_size == 4) {
5642 		/* 64 bit value containing 32 bit address */
5643 		unsigned int i = CAST_DOWN_EXPLICIT(unsigned int, ua);   /* SAFE */
5644 
5645 		error = copyout(&i, ptr, 4);
5646 	} else {
5647 		error = copyout(&ua, ptr, 8);
5648 	}
5649 	return error;
5650 }
5651 
5652 
5653 /*
5654  * exec_copyout_strings
5655  *
5656  * Copy out the strings segment to user space.  The strings segment is put
5657  * on a preinitialized stack frame.
5658  *
5659  * Parameters:	struct image_params *	the image parameter block
5660  *		int *			a pointer to the stack offset variable
5661  *
5662  * Returns:	0			Success
5663  *		!0			Faiure: errno
5664  *
5665  * Implicit returns:
5666  *		(*stackp)		The stack offset, modified
5667  *
5668  * Note:	The strings segment layout is backward, from the beginning
5669  *		of the top of the stack to consume the minimal amount of
5670  *		space possible; the returned stack pointer points to the
5671  *		end of the area consumed (stacks grow downward).
5672  *
5673  *		argc is an int; arg[i] are pointers; env[i] are pointers;
5674  *		the 0's are (void *)NULL's
5675  *
5676  * The stack frame layout is:
5677  *
5678  *      +-------------+ <- p->user_stack
5679  *      |     16b     |
5680  *      +-------------+
5681  *      | STRING AREA |
5682  *      |      :      |
5683  *      |      :      |
5684  *      |      :      |
5685  *      +- -- -- -- --+
5686  *      |  PATH AREA  |
5687  *      +-------------+
5688  *      |      0      |
5689  *      +-------------+
5690  *      |  applev[n]  |
5691  *      +-------------+
5692  *             :
5693  *             :
5694  *      +-------------+
5695  *      |  applev[1]  |
5696  *      +-------------+
5697  *      | exec_path / |
5698  *      |  applev[0]  |
5699  *      +-------------+
5700  *      |      0      |
5701  *      +-------------+
5702  *      |    env[n]   |
5703  *      +-------------+
5704  *             :
5705  *             :
5706  *      +-------------+
5707  *      |    env[0]   |
5708  *      +-------------+
5709  *      |      0      |
5710  *      +-------------+
5711  *      | arg[argc-1] |
5712  *      +-------------+
5713  *             :
5714  *             :
5715  *      +-------------+
5716  *      |    arg[0]   |
5717  *      +-------------+
5718  *      |     argc    |
5719  * sp-> +-------------+
5720  *
5721  * Although technically a part of the STRING AREA, we treat the PATH AREA as
5722  * a separate entity.  This allows us to align the beginning of the PATH AREA
5723  * to a pointer boundary so that the exec_path, env[i], and argv[i] pointers
5724  * which preceed it on the stack are properly aligned.
5725  */
5726 __attribute__((noinline))
5727 static int
exec_copyout_strings(struct image_params * imgp,user_addr_t * stackp)5728 exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp)
5729 {
5730 	proc_t p = vfs_context_proc(imgp->ip_vfs_context);
5731 	int     ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) ? 8 : 4;
5732 	int     ptr_area_size;
5733 	void *ptr_buffer_start, *ptr_buffer;
5734 	size_t string_size;
5735 
5736 	user_addr_t     string_area;    /* *argv[], *env[] */
5737 	user_addr_t     ptr_area;       /* argv[], env[], applev[] */
5738 	user_addr_t argc_area;  /* argc */
5739 	user_addr_t     stack;
5740 	int error;
5741 
5742 	unsigned i;
5743 	struct copyout_desc {
5744 		char    *start_string;
5745 		int             count;
5746 #if CONFIG_DTRACE
5747 		user_addr_t     *dtrace_cookie;
5748 #endif
5749 		boolean_t       null_term;
5750 	} descriptors[] = {
5751 		{
5752 			.start_string = imgp->ip_startargv,
5753 			.count = imgp->ip_argc,
5754 #if CONFIG_DTRACE
5755 			.dtrace_cookie = &p->p_dtrace_argv,
5756 #endif
5757 			.null_term = TRUE
5758 		},
5759 		{
5760 			.start_string = imgp->ip_endargv,
5761 			.count = imgp->ip_envc,
5762 #if CONFIG_DTRACE
5763 			.dtrace_cookie = &p->p_dtrace_envp,
5764 #endif
5765 			.null_term = TRUE
5766 		},
5767 		{
5768 			.start_string = imgp->ip_strings,
5769 			.count = 1,
5770 #if CONFIG_DTRACE
5771 			.dtrace_cookie = NULL,
5772 #endif
5773 			.null_term = FALSE
5774 		},
5775 		{
5776 			.start_string = imgp->ip_endenvv,
5777 			.count = imgp->ip_applec - 1, /* exec_path handled above */
5778 #if CONFIG_DTRACE
5779 			.dtrace_cookie = NULL,
5780 #endif
5781 			.null_term = TRUE
5782 		}
5783 	};
5784 
5785 	stack = *stackp;
5786 
5787 	/*
5788 	 * All previous contributors to the string area
5789 	 * should have aligned their sub-area
5790 	 */
5791 	if (imgp->ip_strspace % ptr_size != 0) {
5792 		error = EINVAL;
5793 		goto bad;
5794 	}
5795 
5796 	/* Grow the stack down for the strings we've been building up */
5797 	string_size = imgp->ip_strendp - imgp->ip_strings;
5798 	stack -= string_size;
5799 	string_area = stack;
5800 
5801 	/*
5802 	 * Need room for one pointer for each string, plus
5803 	 * one for the NULLs terminating the argv, envv, and apple areas.
5804 	 */
5805 	ptr_area_size = (imgp->ip_argc + imgp->ip_envc + imgp->ip_applec + 3) * ptr_size;
5806 	stack -= ptr_area_size;
5807 	ptr_area = stack;
5808 
5809 	/* We'll construct all the pointer arrays in our string buffer,
5810 	 * which we already know is aligned properly, and ip_argspace
5811 	 * was used to verify we have enough space.
5812 	 */
5813 	ptr_buffer_start = ptr_buffer = (void *)imgp->ip_strendp;
5814 
5815 	/*
5816 	 * Need room for pointer-aligned argc slot.
5817 	 */
5818 	stack -= ptr_size;
5819 	argc_area = stack;
5820 
5821 	/*
5822 	 * Record the size of the arguments area so that sysctl_procargs()
5823 	 * can return the argument area without having to parse the arguments.
5824 	 */
5825 	proc_lock(p);
5826 	p->p_argc = imgp->ip_argc;
5827 	p->p_argslen = (int)(*stackp - string_area);
5828 	proc_unlock(p);
5829 
5830 	/* Return the initial stack address: the location of argc */
5831 	*stackp = stack;
5832 
5833 	/*
5834 	 * Copy out the entire strings area.
5835 	 */
5836 	error = copyout(imgp->ip_strings, string_area,
5837 	    string_size);
5838 	if (error) {
5839 		goto bad;
5840 	}
5841 
5842 	for (i = 0; i < sizeof(descriptors) / sizeof(descriptors[0]); i++) {
5843 		char *cur_string = descriptors[i].start_string;
5844 		int j;
5845 
5846 #if CONFIG_DTRACE
5847 		if (descriptors[i].dtrace_cookie) {
5848 			proc_lock(p);
5849 			*descriptors[i].dtrace_cookie = ptr_area + ((uintptr_t)ptr_buffer - (uintptr_t)ptr_buffer_start); /* dtrace convenience */
5850 			proc_unlock(p);
5851 		}
5852 #endif /* CONFIG_DTRACE */
5853 
5854 		/*
5855 		 * For each segment (argv, envv, applev), copy as many pointers as requested
5856 		 * to our pointer buffer.
5857 		 */
5858 		for (j = 0; j < descriptors[i].count; j++) {
5859 			user_addr_t cur_address = string_area + (cur_string - imgp->ip_strings);
5860 
5861 			/* Copy out the pointer to the current string. Alignment has been verified  */
5862 			if (ptr_size == 8) {
5863 				*(uint64_t *)ptr_buffer = (uint64_t)cur_address;
5864 			} else {
5865 				*(uint32_t *)ptr_buffer = (uint32_t)cur_address;
5866 			}
5867 
5868 			ptr_buffer = (void *)((uintptr_t)ptr_buffer + ptr_size);
5869 			cur_string += strlen(cur_string) + 1; /* Only a NUL between strings in the same area */
5870 		}
5871 
5872 		if (descriptors[i].null_term) {
5873 			if (ptr_size == 8) {
5874 				*(uint64_t *)ptr_buffer = 0ULL;
5875 			} else {
5876 				*(uint32_t *)ptr_buffer = 0;
5877 			}
5878 
5879 			ptr_buffer = (void *)((uintptr_t)ptr_buffer + ptr_size);
5880 		}
5881 	}
5882 
5883 	/*
5884 	 * Copy out all our pointer arrays in bulk.
5885 	 */
5886 	error = copyout(ptr_buffer_start, ptr_area,
5887 	    ptr_area_size);
5888 	if (error) {
5889 		goto bad;
5890 	}
5891 
5892 	/* argc (int32, stored in a ptr_size area) */
5893 	error = copyoutptr((user_addr_t)imgp->ip_argc, argc_area, ptr_size);
5894 	if (error) {
5895 		goto bad;
5896 	}
5897 
5898 bad:
5899 	return error;
5900 }
5901 
5902 
5903 /*
5904  * exec_extract_strings
5905  *
5906  * Copy arguments and environment from user space into work area; we may
5907  * have already copied some early arguments into the work area, and if
5908  * so, any arguments opied in are appended to those already there.
5909  * This function is the primary manipulator of ip_argspace, since
5910  * these are the arguments the client of execve(2) knows about. After
5911  * each argv[]/envv[] string is copied, we charge the string length
5912  * and argv[]/envv[] pointer slot to ip_argspace, so that we can
5913  * full preflight the arg list size.
5914  *
5915  * Parameters:	struct image_params *	the image parameter block
5916  *
5917  * Returns:	0			Success
5918  *		!0			Failure: errno
5919  *
5920  * Implicit returns;
5921  *		(imgp->ip_argc)		Count of arguments, updated
5922  *		(imgp->ip_envc)		Count of environment strings, updated
5923  *		(imgp->ip_argspace)	Count of remaining of NCARGS
5924  *		(imgp->ip_interp_buffer)	Interpreter and args (mutated in place)
5925  *
5926  *
5927  * Note:	The argument and environment vectors are user space pointers
5928  *		to arrays of user space pointers.
5929  */
5930 __attribute__((noinline))
5931 static int
exec_extract_strings(struct image_params * imgp)5932 exec_extract_strings(struct image_params *imgp)
5933 {
5934 	int error = 0;
5935 	int     ptr_size = (imgp->ip_flags & IMGPF_WAS_64BIT_ADDR) ? 8 : 4;
5936 	int new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) ? 8 : 4;
5937 	user_addr_t     argv = imgp->ip_user_argv;
5938 	user_addr_t     envv = imgp->ip_user_envv;
5939 
5940 	/*
5941 	 * Adjust space reserved for the path name by however much padding it
5942 	 * needs. Doing this here since we didn't know if this would be a 32-
5943 	 * or 64-bit process back in exec_save_path.
5944 	 */
5945 	while (imgp->ip_strspace % new_ptr_size != 0) {
5946 		*imgp->ip_strendp++ = '\0';
5947 		imgp->ip_strspace--;
5948 		/* imgp->ip_argspace--; not counted towards exec args total */
5949 	}
5950 
5951 	/*
5952 	 * From now on, we start attributing string space to ip_argspace
5953 	 */
5954 	imgp->ip_startargv = imgp->ip_strendp;
5955 	imgp->ip_argc = 0;
5956 
5957 	if ((imgp->ip_flags & IMGPF_INTERPRET) != 0) {
5958 		user_addr_t     arg;
5959 		char *argstart, *ch;
5960 
5961 		/* First, the arguments in the "#!" string are tokenized and extracted. */
5962 		argstart = imgp->ip_interp_buffer;
5963 		while (argstart) {
5964 			ch = argstart;
5965 			while (*ch && !IS_WHITESPACE(*ch)) {
5966 				ch++;
5967 			}
5968 
5969 			if (*ch == '\0') {
5970 				/* last argument, no need to NUL-terminate */
5971 				error = exec_add_user_string(imgp, CAST_USER_ADDR_T(argstart), UIO_SYSSPACE, TRUE);
5972 				argstart = NULL;
5973 			} else {
5974 				/* NUL-terminate */
5975 				*ch = '\0';
5976 				error = exec_add_user_string(imgp, CAST_USER_ADDR_T(argstart), UIO_SYSSPACE, TRUE);
5977 
5978 				/*
5979 				 * Find the next string. We know spaces at the end of the string have already
5980 				 * been stripped.
5981 				 */
5982 				argstart = ch + 1;
5983 				while (IS_WHITESPACE(*argstart)) {
5984 					argstart++;
5985 				}
5986 			}
5987 
5988 			/* Error-check, regardless of whether this is the last interpreter arg or not */
5989 			if (error) {
5990 				goto bad;
5991 			}
5992 			if (imgp->ip_argspace < new_ptr_size) {
5993 				error = E2BIG;
5994 				goto bad;
5995 			}
5996 			imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */
5997 			imgp->ip_argc++;
5998 		}
5999 
6000 		if (argv != 0LL) {
6001 			/*
6002 			 * If we are running an interpreter, replace the av[0] that was
6003 			 * passed to execve() with the path name that was
6004 			 * passed to execve() for interpreters which do not use the PATH
6005 			 * to locate their script arguments.
6006 			 */
6007 			error = copyinptr(argv, &arg, ptr_size);
6008 			if (error) {
6009 				goto bad;
6010 			}
6011 			if (arg != 0LL) {
6012 				argv += ptr_size; /* consume without using */
6013 			}
6014 		}
6015 
6016 		if (imgp->ip_interp_sugid_fd != -1) {
6017 			char temp[19]; /* "/dev/fd/" + 10 digits + NUL */
6018 			snprintf(temp, sizeof(temp), "/dev/fd/%d", imgp->ip_interp_sugid_fd);
6019 			error = exec_add_user_string(imgp, CAST_USER_ADDR_T(temp), UIO_SYSSPACE, TRUE);
6020 		} else {
6021 			error = exec_add_user_string(imgp, imgp->ip_user_fname, imgp->ip_seg, TRUE);
6022 		}
6023 
6024 		if (error) {
6025 			goto bad;
6026 		}
6027 		if (imgp->ip_argspace < new_ptr_size) {
6028 			error = E2BIG;
6029 			goto bad;
6030 		}
6031 		imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */
6032 		imgp->ip_argc++;
6033 	}
6034 
6035 	while (argv != 0LL) {
6036 		user_addr_t     arg;
6037 
6038 		error = copyinptr(argv, &arg, ptr_size);
6039 		if (error) {
6040 			goto bad;
6041 		}
6042 
6043 		if (arg == 0LL) {
6044 			break;
6045 		}
6046 
6047 		argv += ptr_size;
6048 
6049 		/*
6050 		 * av[n...] = arg[n]
6051 		 */
6052 		error = exec_add_user_string(imgp, arg, imgp->ip_seg, TRUE);
6053 		if (error) {
6054 			goto bad;
6055 		}
6056 		if (imgp->ip_argspace < new_ptr_size) {
6057 			error = E2BIG;
6058 			goto bad;
6059 		}
6060 		imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */
6061 		imgp->ip_argc++;
6062 	}
6063 
6064 	/* Save space for argv[] NULL terminator */
6065 	if (imgp->ip_argspace < new_ptr_size) {
6066 		error = E2BIG;
6067 		goto bad;
6068 	}
6069 	imgp->ip_argspace -= new_ptr_size;
6070 
6071 	/* Note where the args ends and env begins. */
6072 	imgp->ip_endargv = imgp->ip_strendp;
6073 	imgp->ip_envc = 0;
6074 
6075 	/* Now, get the environment */
6076 	while (envv != 0LL) {
6077 		user_addr_t     env;
6078 
6079 		error = copyinptr(envv, &env, ptr_size);
6080 		if (error) {
6081 			goto bad;
6082 		}
6083 
6084 		envv += ptr_size;
6085 		if (env == 0LL) {
6086 			break;
6087 		}
6088 		/*
6089 		 * av[n...] = env[n]
6090 		 */
6091 		error = exec_add_user_string(imgp, env, imgp->ip_seg, TRUE);
6092 		if (error) {
6093 			goto bad;
6094 		}
6095 		if (imgp->ip_argspace < new_ptr_size) {
6096 			error = E2BIG;
6097 			goto bad;
6098 		}
6099 		imgp->ip_argspace -= new_ptr_size; /* to hold envv[] entry */
6100 		imgp->ip_envc++;
6101 	}
6102 
6103 	/* Save space for envv[] NULL terminator */
6104 	if (imgp->ip_argspace < new_ptr_size) {
6105 		error = E2BIG;
6106 		goto bad;
6107 	}
6108 	imgp->ip_argspace -= new_ptr_size;
6109 
6110 	/* Align the tail of the combined argv+envv area */
6111 	while (imgp->ip_strspace % new_ptr_size != 0) {
6112 		if (imgp->ip_argspace < 1) {
6113 			error = E2BIG;
6114 			goto bad;
6115 		}
6116 		*imgp->ip_strendp++ = '\0';
6117 		imgp->ip_strspace--;
6118 		imgp->ip_argspace--;
6119 	}
6120 
6121 	/* Note where the envv ends and applev begins. */
6122 	imgp->ip_endenvv = imgp->ip_strendp;
6123 
6124 	/*
6125 	 * From now on, we are no longer charging argument
6126 	 * space to ip_argspace.
6127 	 */
6128 
6129 bad:
6130 	return error;
6131 }
6132 
6133 /*
6134  * Libc has an 8-element array set up for stack guard values.  It only fills
6135  * in one of those entries, and both gcc and llvm seem to use only a single
6136  * 8-byte guard.  Until somebody needs more than an 8-byte guard value, don't
6137  * do the work to construct them.
6138  */
6139 #define GUARD_VALUES 1
6140 #define GUARD_KEY "stack_guard="
6141 
6142 /*
6143  * System malloc needs some entropy when it is initialized.
6144  */
6145 #define ENTROPY_VALUES 2
6146 #define ENTROPY_KEY "malloc_entropy="
6147 
6148 /*
6149  * libplatform needs a random pointer-obfuscation value when it is initialized.
6150  */
6151 #define PTR_MUNGE_VALUES 1
6152 #define PTR_MUNGE_KEY "ptr_munge="
6153 
6154 /*
6155  * System malloc engages nanozone for UIAPP.
6156  */
6157 #define NANO_ENGAGE_KEY "MallocNanoZone=1"
6158 
6159 /*
6160  * Used to pass experiment flags up to libmalloc.
6161  */
6162 #define LIBMALLOC_EXPERIMENT_FACTORS_KEY "MallocExperiment="
6163 
6164 /*
6165  * Passes information about hardened runtime entitlements to libsystem/libmalloc
6166  */
6167 #define HARDENED_RUNTIME_KEY "HardenedRuntime="
6168 
6169 #define PFZ_KEY "pfz="
6170 extern user32_addr_t commpage_text32_location;
6171 extern user64_addr_t commpage_text64_location;
6172 
6173 extern uuid_string_t bootsessionuuid_string;
6174 static TUNABLE(uint32_t, exe_boothash_salt, "exe_boothash_salt", 0);
6175 
6176 __startup_func
6177 static void
exe_boothash_salt_generate(void)6178 exe_boothash_salt_generate(void)
6179 {
6180 	if (!PE_parse_boot_argn("exe_boothash_salt", NULL, 0)) {
6181 		read_random(&exe_boothash_salt, sizeof(exe_boothash_salt));
6182 	}
6183 }
6184 STARTUP(EARLY_BOOT, STARTUP_RANK_MIDDLE, exe_boothash_salt_generate);
6185 
6186 
6187 #define MAIN_STACK_VALUES 4
6188 #define MAIN_STACK_KEY "main_stack="
6189 
6190 #define FSID_KEY "executable_file="
6191 #define DYLD_FSID_KEY "dyld_file="
6192 #define CDHASH_KEY "executable_cdhash="
6193 #define DYLD_FLAGS_KEY "dyld_flags="
6194 #define SUBSYSTEM_ROOT_PATH_KEY "subsystem_root_path="
6195 #define APP_BOOT_SESSION_KEY "executable_boothash="
6196 #if __has_feature(ptrauth_calls)
6197 #define PTRAUTH_DISABLED_FLAG "ptrauth_disabled=1"
6198 #define DYLD_ARM64E_ABI_KEY "arm64e_abi="
6199 #endif /* __has_feature(ptrauth_calls) */
6200 #define MAIN_TH_PORT_KEY "th_port="
6201 
6202 #define FSID_MAX_STRING "0x1234567890abcdef,0x1234567890abcdef"
6203 
6204 #define HEX_STR_LEN 18 // 64-bit hex value "0x0123456701234567"
6205 #define HEX_STR_LEN32 10 // 32-bit hex value "0x01234567"
6206 
6207 #if XNU_TARGET_OS_OSX && _POSIX_SPAWN_FORCE_4K_PAGES && PMAP_CREATE_FORCE_4K_PAGES
6208 #define VM_FORCE_4K_PAGES_KEY "vm_force_4k_pages=1"
6209 #endif /* XNU_TARGET_OS_OSX && _POSIX_SPAWN_FORCE_4K_PAGES && PMAP_CREATE_FORCE_4K_PAGES */
6210 
6211 static int
exec_add_entropy_key(struct image_params * imgp,const char * key,int values,boolean_t embedNUL)6212 exec_add_entropy_key(struct image_params *imgp,
6213     const char *key,
6214     int values,
6215     boolean_t embedNUL)
6216 {
6217 	const int limit = 8;
6218 	uint64_t entropy[limit];
6219 	char str[strlen(key) + (HEX_STR_LEN + 1) * limit + 1];
6220 	if (values > limit) {
6221 		values = limit;
6222 	}
6223 
6224 	read_random(entropy, sizeof(entropy[0]) * values);
6225 
6226 	if (embedNUL) {
6227 		entropy[0] &= ~(0xffull << 8);
6228 	}
6229 
6230 	int len = scnprintf(str, sizeof(str), "%s0x%llx", key, entropy[0]);
6231 	size_t remaining = sizeof(str) - len;
6232 	for (int i = 1; i < values && remaining > 0; ++i) {
6233 		size_t start = sizeof(str) - remaining;
6234 		len = scnprintf(&str[start], remaining, ",0x%llx", entropy[i]);
6235 		remaining -= len;
6236 	}
6237 
6238 	return exec_add_user_string(imgp, CAST_USER_ADDR_T(str), UIO_SYSSPACE, FALSE);
6239 }
6240 
6241 /*
6242  * Build up the contents of the apple[] string vector
6243  */
6244 #if (DEVELOPMENT || DEBUG)
6245 extern uint64_t dyld_flags;
6246 #endif
6247 
6248 #if __has_feature(ptrauth_calls)
6249 static inline bool
is_arm64e_running_as_arm64(const struct image_params * imgp)6250 is_arm64e_running_as_arm64(const struct image_params *imgp)
6251 {
6252 	return (imgp->ip_origcpusubtype & ~CPU_SUBTYPE_MASK) == CPU_SUBTYPE_ARM64E &&
6253 	       (imgp->ip_flags & IMGPF_NOJOP);
6254 }
6255 #endif /* __has_feature(ptrauth_calls) */
6256 
6257 _Atomic uint64_t libmalloc_experiment_factors = 0;
6258 
6259 static int
exec_add_apple_strings(struct image_params * imgp,const load_result_t * load_result,task_t task)6260 exec_add_apple_strings(struct image_params *imgp,
6261     const load_result_t *load_result, task_t task)
6262 {
6263 	int error;
6264 	int img_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) ? 8 : 4;
6265 	thread_t new_thread;
6266 	ipc_port_t sright;
6267 	uint64_t local_experiment_factors = 0;
6268 
6269 	/* exec_save_path stored the first string */
6270 	imgp->ip_applec = 1;
6271 
6272 	/* adding the pfz string */
6273 	{
6274 		char pfz_string[strlen(PFZ_KEY) + HEX_STR_LEN + 1];
6275 
6276 		if (img_ptr_size == 8) {
6277 			__assert_only size_t ret = snprintf(pfz_string, sizeof(pfz_string), PFZ_KEY "0x%llx", commpage_text64_location);
6278 			assert(ret < sizeof(pfz_string));
6279 		} else {
6280 			snprintf(pfz_string, sizeof(pfz_string), PFZ_KEY "0x%x", commpage_text32_location);
6281 		}
6282 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(pfz_string), UIO_SYSSPACE, FALSE);
6283 		if (error) {
6284 			printf("Failed to add the pfz string with error %d\n", error);
6285 			goto bad;
6286 		}
6287 		imgp->ip_applec++;
6288 	}
6289 
6290 	/* adding the NANO_ENGAGE_KEY key */
6291 	if (imgp->ip_px_sa) {
6292 		struct _posix_spawnattr* psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
6293 		int proc_flags = psa->psa_flags;
6294 
6295 		if ((proc_flags & _POSIX_SPAWN_NANO_ALLOCATOR) == _POSIX_SPAWN_NANO_ALLOCATOR) {
6296 			const char *nano_string = NANO_ENGAGE_KEY;
6297 			error = exec_add_user_string(imgp, CAST_USER_ADDR_T(nano_string), UIO_SYSSPACE, FALSE);
6298 			if (error) {
6299 				goto bad;
6300 			}
6301 			imgp->ip_applec++;
6302 		}
6303 	}
6304 
6305 	/*
6306 	 * Supply libc with a collection of random values to use when
6307 	 * implementing -fstack-protector.
6308 	 *
6309 	 * (The first random string always contains an embedded NUL so that
6310 	 * __stack_chk_guard also protects against C string vulnerabilities)
6311 	 */
6312 	error = exec_add_entropy_key(imgp, GUARD_KEY, GUARD_VALUES, TRUE);
6313 	if (error) {
6314 		goto bad;
6315 	}
6316 	imgp->ip_applec++;
6317 
6318 	/*
6319 	 * Supply libc with entropy for system malloc.
6320 	 */
6321 	error = exec_add_entropy_key(imgp, ENTROPY_KEY, ENTROPY_VALUES, FALSE);
6322 	if (error) {
6323 		goto bad;
6324 	}
6325 	imgp->ip_applec++;
6326 
6327 	/*
6328 	 * Supply libpthread & libplatform with a random value to use for pointer
6329 	 * obfuscation.
6330 	 */
6331 	error = exec_add_entropy_key(imgp, PTR_MUNGE_KEY, PTR_MUNGE_VALUES, FALSE);
6332 	if (error) {
6333 		goto bad;
6334 	}
6335 	imgp->ip_applec++;
6336 
6337 	/*
6338 	 * Add MAIN_STACK_KEY: Supplies the address and size of the main thread's
6339 	 * stack if it was allocated by the kernel.
6340 	 *
6341 	 * The guard page is not included in this stack size as libpthread
6342 	 * expects to add it back in after receiving this value.
6343 	 */
6344 	if (load_result->unixproc) {
6345 		char stack_string[strlen(MAIN_STACK_KEY) + (HEX_STR_LEN + 1) * MAIN_STACK_VALUES + 1];
6346 		snprintf(stack_string, sizeof(stack_string),
6347 		    MAIN_STACK_KEY "0x%llx,0x%llx,0x%llx,0x%llx",
6348 		    (uint64_t)load_result->user_stack,
6349 		    (uint64_t)load_result->user_stack_size,
6350 		    (uint64_t)load_result->user_stack_alloc,
6351 		    (uint64_t)load_result->user_stack_alloc_size);
6352 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(stack_string), UIO_SYSSPACE, FALSE);
6353 		if (error) {
6354 			goto bad;
6355 		}
6356 		imgp->ip_applec++;
6357 	}
6358 
6359 	if (imgp->ip_vattr) {
6360 		uint64_t fsid    = vnode_get_va_fsid(imgp->ip_vattr);
6361 		uint64_t fsobjid = imgp->ip_vattr->va_fileid;
6362 
6363 		char fsid_string[strlen(FSID_KEY) + strlen(FSID_MAX_STRING) + 1];
6364 		snprintf(fsid_string, sizeof(fsid_string),
6365 		    FSID_KEY "0x%llx,0x%llx", fsid, fsobjid);
6366 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(fsid_string), UIO_SYSSPACE, FALSE);
6367 		if (error) {
6368 			goto bad;
6369 		}
6370 		imgp->ip_applec++;
6371 	}
6372 
6373 	if (imgp->ip_dyld_fsid || imgp->ip_dyld_fsobjid) {
6374 		char fsid_string[strlen(DYLD_FSID_KEY) + strlen(FSID_MAX_STRING) + 1];
6375 		snprintf(fsid_string, sizeof(fsid_string),
6376 		    DYLD_FSID_KEY "0x%llx,0x%llx", imgp->ip_dyld_fsid, imgp->ip_dyld_fsobjid);
6377 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(fsid_string), UIO_SYSSPACE, FALSE);
6378 		if (error) {
6379 			goto bad;
6380 		}
6381 		imgp->ip_applec++;
6382 	}
6383 
6384 	uint8_t cdhash[SHA1_RESULTLEN];
6385 	int cdhash_errror = ubc_cs_getcdhash(imgp->ip_vp, imgp->ip_arch_offset, cdhash, NULL);
6386 	if (cdhash_errror == 0) {
6387 		char hash_string[strlen(CDHASH_KEY) + 2 * SHA1_RESULTLEN + 1];
6388 		strncpy(hash_string, CDHASH_KEY, sizeof(hash_string));
6389 		char *p = hash_string + sizeof(CDHASH_KEY) - 1;
6390 		for (int i = 0; i < SHA1_RESULTLEN; i++) {
6391 			snprintf(p, 3, "%02x", (int) cdhash[i]);
6392 			p += 2;
6393 		}
6394 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(hash_string), UIO_SYSSPACE, FALSE);
6395 		if (error) {
6396 			goto bad;
6397 		}
6398 		imgp->ip_applec++;
6399 
6400 		/* hash together cd-hash and boot-session-uuid */
6401 		uint8_t sha_digest[SHA256_DIGEST_LENGTH];
6402 		SHA256_CTX sha_ctx;
6403 		SHA256_Init(&sha_ctx);
6404 		SHA256_Update(&sha_ctx, &exe_boothash_salt, sizeof(exe_boothash_salt));
6405 		SHA256_Update(&sha_ctx, bootsessionuuid_string, sizeof(bootsessionuuid_string));
6406 		SHA256_Update(&sha_ctx, cdhash, sizeof(cdhash));
6407 		SHA256_Final(sha_digest, &sha_ctx);
6408 		char app_boot_string[strlen(APP_BOOT_SESSION_KEY) + 2 * SHA1_RESULTLEN + 1];
6409 		strncpy(app_boot_string, APP_BOOT_SESSION_KEY, sizeof(app_boot_string));
6410 		char *s = app_boot_string + sizeof(APP_BOOT_SESSION_KEY) - 1;
6411 		for (int i = 0; i < SHA1_RESULTLEN; i++) {
6412 			snprintf(s, 3, "%02x", (int) sha_digest[i]);
6413 			s += 2;
6414 		}
6415 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(app_boot_string), UIO_SYSSPACE, FALSE);
6416 		if (error) {
6417 			goto bad;
6418 		}
6419 		imgp->ip_applec++;
6420 	}
6421 #if (DEVELOPMENT || DEBUG)
6422 	if (dyld_flags) {
6423 		char dyld_flags_string[strlen(DYLD_FLAGS_KEY) + HEX_STR_LEN + 1];
6424 		snprintf(dyld_flags_string, sizeof(dyld_flags_string), DYLD_FLAGS_KEY "0x%llx", dyld_flags);
6425 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(dyld_flags_string), UIO_SYSSPACE, FALSE);
6426 		if (error) {
6427 			goto bad;
6428 		}
6429 		imgp->ip_applec++;
6430 	}
6431 #endif
6432 	if (imgp->ip_subsystem_root_path) {
6433 		size_t buffer_len = MAXPATHLEN + strlen(SUBSYSTEM_ROOT_PATH_KEY);
6434 		char subsystem_root_path_string[buffer_len];
6435 		int required_len = snprintf(subsystem_root_path_string, buffer_len, SUBSYSTEM_ROOT_PATH_KEY "%s", imgp->ip_subsystem_root_path);
6436 
6437 		if (((size_t)required_len >= buffer_len) || (required_len < 0)) {
6438 			error = ENAMETOOLONG;
6439 			goto bad;
6440 		}
6441 
6442 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(subsystem_root_path_string), UIO_SYSSPACE, FALSE);
6443 		if (error) {
6444 			goto bad;
6445 		}
6446 
6447 		imgp->ip_applec++;
6448 	}
6449 #if __has_feature(ptrauth_calls)
6450 	if (is_arm64e_running_as_arm64(imgp)) {
6451 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(PTRAUTH_DISABLED_FLAG), UIO_SYSSPACE, FALSE);
6452 		if (error) {
6453 			goto bad;
6454 		}
6455 
6456 		imgp->ip_applec++;
6457 	}
6458 #endif /* __has_feature(ptrauth_calls) */
6459 
6460 
6461 #if __has_feature(ptrauth_calls) && defined(XNU_TARGET_OS_OSX)
6462 	{
6463 		char dyld_abi_string[strlen(DYLD_ARM64E_ABI_KEY) + 8];
6464 		strlcpy(dyld_abi_string, DYLD_ARM64E_ABI_KEY, sizeof(dyld_abi_string));
6465 		bool allowAll = bootarg_arm64e_preview_abi;
6466 		strlcat(dyld_abi_string, (allowAll ? "all" : "os"), sizeof(dyld_abi_string));
6467 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(dyld_abi_string), UIO_SYSSPACE, FALSE);
6468 		if (error) {
6469 			goto bad;
6470 		}
6471 
6472 		imgp->ip_applec++;
6473 	}
6474 #endif
6475 	/*
6476 	 * Add main thread mach port name
6477 	 * +1 uref on main thread port, this ref will be extracted by libpthread in __pthread_init
6478 	 * and consumed in _bsdthread_terminate. Leaking the main thread port name if not linked
6479 	 * against libpthread.
6480 	 */
6481 	if ((new_thread = imgp->ip_new_thread) != THREAD_NULL) {
6482 		thread_reference(new_thread);
6483 		sright = convert_thread_to_port_pinned(new_thread);
6484 		task_t new_task = get_threadtask(new_thread);
6485 		mach_port_name_t name = ipc_port_copyout_send(sright, get_task_ipcspace(new_task));
6486 		char port_name_hex_str[strlen(MAIN_TH_PORT_KEY) + HEX_STR_LEN32 + 1];
6487 		snprintf(port_name_hex_str, sizeof(port_name_hex_str), MAIN_TH_PORT_KEY "0x%x", name);
6488 
6489 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(port_name_hex_str), UIO_SYSSPACE, FALSE);
6490 		if (error) {
6491 			goto bad;
6492 		}
6493 		imgp->ip_applec++;
6494 	}
6495 
6496 #if XNU_TARGET_OS_OSX && _POSIX_SPAWN_FORCE_4K_PAGES && PMAP_CREATE_FORCE_4K_PAGES
6497 	if (imgp->ip_px_sa != NULL) {
6498 		struct _posix_spawnattr* psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
6499 		if (psa->psa_flags & _POSIX_SPAWN_FORCE_4K_PAGES) {
6500 			const char *vm_force_4k_string = VM_FORCE_4K_PAGES_KEY;
6501 			error = exec_add_user_string(imgp, CAST_USER_ADDR_T(vm_force_4k_string), UIO_SYSSPACE, FALSE);
6502 			if (error) {
6503 				goto bad;
6504 			}
6505 			imgp->ip_applec++;
6506 		}
6507 	}
6508 #endif /* XNU_TARGET_OS_OSX && _POSIX_SPAWN_FORCE_4K_PAGES && PMAP_CREATE_FORCE_4K_PAGES */
6509 
6510 	/* adding the libmalloc experiment string */
6511 	local_experiment_factors = os_atomic_load_wide(&libmalloc_experiment_factors, relaxed);
6512 	if (__improbable(local_experiment_factors != 0)) {
6513 		char libmalloc_experiment_factors_string[strlen(LIBMALLOC_EXPERIMENT_FACTORS_KEY) + HEX_STR_LEN + 1];
6514 
6515 		snprintf(
6516 			libmalloc_experiment_factors_string,
6517 			sizeof(libmalloc_experiment_factors_string),
6518 			LIBMALLOC_EXPERIMENT_FACTORS_KEY "0x%llx",
6519 			local_experiment_factors);
6520 		error = exec_add_user_string(
6521 			imgp,
6522 			CAST_USER_ADDR_T(libmalloc_experiment_factors_string),
6523 			UIO_SYSSPACE,
6524 			FALSE);
6525 		if (error) {
6526 			printf("Failed to add the libmalloc experiment factors string with error %d\n", error);
6527 			goto bad;
6528 		}
6529 		imgp->ip_applec++;
6530 	}
6531 
6532 	/*
6533 	 * Push down the task security configuration. To reduce confusion when userland parses the information
6534 	 * still push an empty security configuration if nothing is active.
6535 	 */
6536 	{
6537 		#define SECURITY_CONFIG_KEY "security_config="
6538 		char security_config_str[strlen(SECURITY_CONFIG_KEY) + HEX_STR_LEN + 1];
6539 
6540 		snprintf(security_config_str, sizeof(security_config_str),
6541 		    SECURITY_CONFIG_KEY "0x%x", task_get_security_config(task));
6542 
6543 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(security_config_str), UIO_SYSSPACE, FALSE);
6544 		if (error) {
6545 			printf("Failed to add the security config string with error %d\n", error);
6546 			goto bad;
6547 		}
6548 		imgp->ip_applec++;
6549 	}
6550 
6551 
6552 
6553 
6554 	if (load_result->hardened_runtime_binary) {
6555 		const size_t HR_STRING_SIZE = sizeof(HARDENED_RUNTIME_KEY) + HR_FLAGS_NUM_NIBBLES + 2 + 1;
6556 		char hardened_runtime[HR_STRING_SIZE];
6557 		snprintf(hardened_runtime, HR_STRING_SIZE, HARDENED_RUNTIME_KEY"0x%x", load_result->hardened_runtime_binary);
6558 		error = exec_add_user_string(imgp, CAST_USER_ADDR_T(hardened_runtime), UIO_SYSSPACE, FALSE);
6559 		if (error) {
6560 			printf("Failed to add hardened runtime flag with error %d\n", error);
6561 			goto bad;
6562 		}
6563 		imgp->ip_applec++;
6564 	}
6565 	/* Align the tail of the combined applev area */
6566 	while (imgp->ip_strspace % img_ptr_size != 0) {
6567 		*imgp->ip_strendp++ = '\0';
6568 		imgp->ip_strspace--;
6569 	}
6570 
6571 bad:
6572 	return error;
6573 }
6574 
6575 /*
6576  * exec_check_permissions
6577  *
6578  * Description:	Verify that the file that is being attempted to be executed
6579  *		is in fact allowed to be executed based on it POSIX file
6580  *		permissions and other access control criteria
6581  *
6582  * Parameters:	struct image_params *	the image parameter block
6583  *
6584  * Returns:	0			Success
6585  *		EACCES			Permission denied
6586  *		ENOEXEC			Executable file format error
6587  *		ETXTBSY			Text file busy [misuse of error code]
6588  *	vnode_getattr:???
6589  *	vnode_authorize:???
6590  */
6591 static int
exec_check_permissions(struct image_params * imgp)6592 exec_check_permissions(struct image_params *imgp)
6593 {
6594 	struct vnode *vp = imgp->ip_vp;
6595 	struct vnode_attr *vap = imgp->ip_vattr;
6596 	proc_t p = vfs_context_proc(imgp->ip_vfs_context);
6597 	int error;
6598 	kauth_action_t action;
6599 
6600 	/* Only allow execution of regular files */
6601 	if (!vnode_isreg(vp)) {
6602 		return EACCES;
6603 	}
6604 
6605 	/* Get the file attributes that we will be using here and elsewhere */
6606 	VATTR_INIT(vap);
6607 	VATTR_WANTED(vap, va_uid);
6608 	VATTR_WANTED(vap, va_gid);
6609 	VATTR_WANTED(vap, va_mode);
6610 	VATTR_WANTED(vap, va_fsid);
6611 	VATTR_WANTED(vap, va_fsid64);
6612 	VATTR_WANTED(vap, va_fileid);
6613 	VATTR_WANTED(vap, va_data_size);
6614 	if ((error = vnode_getattr(vp, vap, imgp->ip_vfs_context)) != 0) {
6615 		return error;
6616 	}
6617 
6618 	/*
6619 	 * Ensure that at least one execute bit is on - otherwise root
6620 	 * will always succeed, and we don't want to happen unless the
6621 	 * file really is executable.
6622 	 */
6623 	if (!vfs_authopaque(vnode_mount(vp)) && ((vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0)) {
6624 		return EACCES;
6625 	}
6626 
6627 	/* Disallow zero length files */
6628 	if (vap->va_data_size == 0) {
6629 		return ENOEXEC;
6630 	}
6631 
6632 	imgp->ip_arch_offset = (user_size_t)0;
6633 #if __LP64__
6634 	imgp->ip_arch_size = vap->va_data_size;
6635 #else
6636 	if (vap->va_data_size > UINT32_MAX) {
6637 		return ENOEXEC;
6638 	}
6639 	imgp->ip_arch_size = (user_size_t)vap->va_data_size;
6640 #endif
6641 
6642 	/* Disable setuid-ness for traced programs or if MNT_NOSUID */
6643 	if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_lflag & P_LTRACED)) {
6644 		vap->va_mode &= ~(VSUID | VSGID);
6645 	}
6646 
6647 	/*
6648 	 * Disable _POSIX_SPAWN_ALLOW_DATA_EXEC and _POSIX_SPAWN_DISABLE_ASLR
6649 	 * flags for setuid/setgid binaries.
6650 	 */
6651 	if (vap->va_mode & (VSUID | VSGID)) {
6652 		imgp->ip_flags &= ~(IMGPF_ALLOW_DATA_EXEC | IMGPF_DISABLE_ASLR);
6653 	}
6654 
6655 #if CONFIG_MACF
6656 	error = mac_vnode_check_exec(imgp->ip_vfs_context, vp, imgp);
6657 	if (error) {
6658 		return error;
6659 	}
6660 #endif
6661 
6662 	/* Check for execute permission */
6663 	action = KAUTH_VNODE_EXECUTE;
6664 	/* Traced images must also be readable */
6665 	if (p->p_lflag & P_LTRACED) {
6666 		action |= KAUTH_VNODE_READ_DATA;
6667 	}
6668 	if ((error = vnode_authorize(vp, NULL, action, imgp->ip_vfs_context)) != 0) {
6669 		return error;
6670 	}
6671 
6672 #if 0
6673 	/* Don't let it run if anyone had it open for writing */
6674 	vnode_lock(vp);
6675 	if (vp->v_writecount) {
6676 		panic("going to return ETXTBSY %x", vp);
6677 		vnode_unlock(vp);
6678 		return ETXTBSY;
6679 	}
6680 	vnode_unlock(vp);
6681 #endif
6682 
6683 	/* XXX May want to indicate to underlying FS that vnode is open */
6684 
6685 	return error;
6686 }
6687 
6688 
6689 /*
6690  * exec_handle_sugid
6691  *
6692  * Initially clear the P_SUGID in the process flags; if an SUGID process is
6693  * exec'ing a non-SUGID image, then  this is the point of no return.
6694  *
6695  * If the image being activated is SUGID, then replace the credential with a
6696  * copy, disable tracing (unless the tracing process is root), reset the
6697  * mach task port to revoke it, set the P_SUGID bit,
6698  *
6699  * If the saved user and group ID will be changing, then make sure it happens
6700  * to a new credential, rather than a shared one.
6701  *
6702  * Set the security token (this is probably obsolete, given that the token
6703  * should not technically be separate from the credential itself).
6704  *
6705  * Parameters:	struct image_params *	the image parameter block
6706  *
6707  * Returns:	void			No failure indication
6708  *
6709  * Implicit returns:
6710  *		<process credential>	Potentially modified/replaced
6711  *		<task port>		Potentially revoked
6712  *		<process flags>		P_SUGID bit potentially modified
6713  *		<security token>	Potentially modified
6714  */
6715 __attribute__((noinline))
6716 static int
exec_handle_sugid(struct image_params * imgp)6717 exec_handle_sugid(struct image_params *imgp)
6718 {
6719 	proc_t                  p = vfs_context_proc(imgp->ip_vfs_context);
6720 	kauth_cred_t            cred = vfs_context_ucred(imgp->ip_vfs_context);
6721 	int                     i;
6722 	int                     leave_sugid_clear = 0;
6723 	int                     mac_reset_ipc = 0;
6724 	int                     error = 0;
6725 #if CONFIG_MACF
6726 	int                     mac_transition, disjoint_cred = 0;
6727 	int             label_update_return = 0;
6728 
6729 	/*
6730 	 * Determine whether a call to update the MAC label will result in the
6731 	 * credential changing.
6732 	 *
6733 	 * Note:	MAC policies which do not actually end up modifying
6734 	 *		the label subsequently are strongly encouraged to
6735 	 *		return 0 for this check, since a non-zero answer will
6736 	 *		slow down the exec fast path for normal binaries.
6737 	 */
6738 	mac_transition = mac_cred_check_label_update_execve(
6739 		imgp->ip_vfs_context,
6740 		imgp->ip_vp,
6741 		imgp->ip_arch_offset,
6742 		imgp->ip_scriptvp,
6743 		imgp->ip_scriptlabelp,
6744 		imgp->ip_execlabelp,
6745 		p,
6746 		&imgp->ip_px_smpx);
6747 #endif
6748 
6749 	OSBitAndAtomic(~((uint32_t)P_SUGID), &p->p_flag);
6750 
6751 	/*
6752 	 * Order of the following is important; group checks must go last,
6753 	 * as we use the success of the 'ismember' check combined with the
6754 	 * failure of the explicit match to indicate that we will be setting
6755 	 * the egid of the process even though the new process did not
6756 	 * require VSUID/VSGID bits in order for it to set the new group as
6757 	 * its egid.
6758 	 *
6759 	 * Note:	Technically, by this we are implying a call to
6760 	 *		setegid() in the new process, rather than implying
6761 	 *		it used its VSGID bit to set the effective group,
6762 	 *		even though there is no code in that process to make
6763 	 *		such a call.
6764 	 */
6765 	if (((imgp->ip_origvattr->va_mode & VSUID) != 0 &&
6766 	    kauth_cred_getuid(cred) != imgp->ip_origvattr->va_uid) ||
6767 	    ((imgp->ip_origvattr->va_mode & VSGID) != 0 &&
6768 	    ((kauth_cred_ismember_gid(cred, imgp->ip_origvattr->va_gid, &leave_sugid_clear) || !leave_sugid_clear) ||
6769 	    (kauth_cred_getgid(cred) != imgp->ip_origvattr->va_gid)))) {
6770 #if CONFIG_MACF
6771 /* label for MAC transition and neither VSUID nor VSGID */
6772 handle_mac_transition:
6773 #endif
6774 
6775 #if CONFIG_SETUID
6776 		/*
6777 		 * Replace the credential with a copy of itself if euid or
6778 		 * egid change.
6779 		 *
6780 		 * Note:	setuid binaries will automatically opt out of
6781 		 *		group resolver participation as a side effect
6782 		 *		of this operation.  This is an intentional
6783 		 *		part of the security model, which requires a
6784 		 *		participating credential be established by
6785 		 *		escalating privilege, setting up all other
6786 		 *		aspects of the credential including whether
6787 		 *		or not to participate in external group
6788 		 *		membership resolution, then dropping their
6789 		 *		effective privilege to that of the desired
6790 		 *		final credential state.
6791 		 *
6792 		 * Modifications to p_ucred must be guarded using the
6793 		 * proc's ucred lock. This prevents others from accessing
6794 		 * a garbage credential.
6795 		 */
6796 
6797 		if (imgp->ip_origvattr->va_mode & VSUID) {
6798 			kauth_cred_proc_update(p, PROC_SETTOKEN_NONE,
6799 			    ^bool (kauth_cred_t parent __unused, kauth_cred_t model) {
6800 				return kauth_cred_model_setresuid(model,
6801 				KAUTH_UID_NONE,
6802 				imgp->ip_origvattr->va_uid,
6803 				imgp->ip_origvattr->va_uid,
6804 				KAUTH_UID_NONE);
6805 			});
6806 		}
6807 
6808 		if (imgp->ip_origvattr->va_mode & VSGID) {
6809 			kauth_cred_proc_update(p, PROC_SETTOKEN_NONE,
6810 			    ^bool (kauth_cred_t parent __unused, kauth_cred_t model) {
6811 				return kauth_cred_model_setresgid(model,
6812 				KAUTH_GID_NONE,
6813 				imgp->ip_origvattr->va_gid,
6814 				imgp->ip_origvattr->va_gid);
6815 			});
6816 		}
6817 #endif /* CONFIG_SETUID */
6818 
6819 #if CONFIG_MACF
6820 		/*
6821 		 * If a policy has indicated that it will transition the label,
6822 		 * before making the call into the MAC policies, get a new
6823 		 * duplicate credential, so they can modify it without
6824 		 * modifying any others sharing it.
6825 		 */
6826 		if (mac_transition) {
6827 			/*
6828 			 * This hook may generate upcalls that require
6829 			 * importance donation from the kernel.
6830 			 * (23925818)
6831 			 */
6832 			thread_t thread = current_thread();
6833 			thread_enable_send_importance(thread, TRUE);
6834 			kauth_proc_label_update_execve(p,
6835 			    imgp->ip_vfs_context,
6836 			    imgp->ip_vp,
6837 			    imgp->ip_arch_offset,
6838 			    imgp->ip_scriptvp,
6839 			    imgp->ip_scriptlabelp,
6840 			    imgp->ip_execlabelp,
6841 			    &imgp->ip_csflags,
6842 			    &imgp->ip_px_smpx,
6843 			    &disjoint_cred,                     /* will be non zero if disjoint */
6844 			    &label_update_return);
6845 			thread_enable_send_importance(thread, FALSE);
6846 
6847 			if (disjoint_cred) {
6848 				/*
6849 				 * If updating the MAC label resulted in a
6850 				 * disjoint credential, flag that we need to
6851 				 * set the P_SUGID bit.  This protects
6852 				 * against debuggers being attached by an
6853 				 * insufficiently privileged process onto the
6854 				 * result of a transition to a more privileged
6855 				 * credential.
6856 				 */
6857 				leave_sugid_clear = 0;
6858 			}
6859 
6860 			imgp->ip_mac_return = label_update_return;
6861 		}
6862 
6863 		mac_reset_ipc = mac_proc_check_inherit_ipc_ports(p, p->p_textvp, p->p_textoff, imgp->ip_vp, imgp->ip_arch_offset, imgp->ip_scriptvp);
6864 
6865 #endif  /* CONFIG_MACF */
6866 
6867 		/*
6868 		 * If 'leave_sugid_clear' is non-zero, then we passed the
6869 		 * VSUID and MACF checks, and successfully determined that
6870 		 * the previous cred was a member of the VSGID group, but
6871 		 * that it was not the default at the time of the execve,
6872 		 * and that the post-labelling credential was not disjoint.
6873 		 * So we don't set the P_SUGID or reset mach ports and fds
6874 		 * on the basis of simply running this code.
6875 		 */
6876 		if (mac_reset_ipc || !leave_sugid_clear) {
6877 			/*
6878 			 * Have mach reset the task and thread ports.
6879 			 * We don't want anyone who had the ports before
6880 			 * a setuid exec to be able to access/control the
6881 			 * task/thread after.
6882 			 */
6883 			ipc_task_reset((imgp->ip_new_thread != NULL) ?
6884 			    get_threadtask(imgp->ip_new_thread) : proc_task(p));
6885 			ipc_thread_reset((imgp->ip_new_thread != NULL) ?
6886 			    imgp->ip_new_thread : current_thread());
6887 		}
6888 
6889 		if (!leave_sugid_clear) {
6890 			/*
6891 			 * Flag the process as setuid.
6892 			 */
6893 			OSBitOrAtomic(P_SUGID, &p->p_flag);
6894 
6895 			/*
6896 			 * Radar 2261856; setuid security hole fix
6897 			 * XXX For setuid processes, attempt to ensure that
6898 			 * stdin, stdout, and stderr are already allocated.
6899 			 * We do not want userland to accidentally allocate
6900 			 * descriptors in this range which has implied meaning
6901 			 * to libc.
6902 			 */
6903 			for (i = 0; i < 3; i++) {
6904 				if (fp_get_noref_locked(p, i) != NULL) {
6905 					continue;
6906 				}
6907 
6908 				/*
6909 				 * Do the kernel equivalent of
6910 				 *
6911 				 *      if i == 0
6912 				 *              (void) open("/dev/null", O_RDONLY);
6913 				 *      else
6914 				 *              (void) open("/dev/null", O_WRONLY);
6915 				 */
6916 
6917 				struct fileproc *fp;
6918 				int indx;
6919 				int flag;
6920 				struct nameidata *ndp = NULL;
6921 
6922 				if (i == 0) {
6923 					flag = FREAD;
6924 				} else {
6925 					flag = FWRITE;
6926 				}
6927 
6928 				if ((error = falloc_exec(p, imgp->ip_vfs_context,
6929 				    &fp, &indx)) != 0) {
6930 					continue;
6931 				}
6932 
6933 				ndp = kalloc_type(struct nameidata,
6934 				    Z_WAITOK | Z_ZERO | Z_NOFAIL);
6935 
6936 				NDINIT(ndp, LOOKUP, OP_OPEN, FOLLOW, UIO_SYSSPACE,
6937 				    CAST_USER_ADDR_T("/dev/null"),
6938 				    imgp->ip_vfs_context);
6939 
6940 				if ((error = vn_open(ndp, flag, 0)) != 0) {
6941 					fp_free(p, indx, fp);
6942 					kfree_type(struct nameidata, ndp);
6943 					break;
6944 				}
6945 
6946 				struct fileglob *fg = fp->fp_glob;
6947 
6948 				fg->fg_flag = flag;
6949 				fg->fg_ops = &vnops;
6950 				fp_set_data(fp, ndp->ni_vp);
6951 
6952 				vnode_put(ndp->ni_vp);
6953 
6954 				proc_fdlock(p);
6955 				procfdtbl_releasefd(p, indx, NULL);
6956 				fp_drop(p, indx, fp, 1);
6957 				proc_fdunlock(p);
6958 
6959 				kfree_type(struct nameidata, ndp);
6960 			}
6961 		}
6962 	}
6963 #if CONFIG_MACF
6964 	else {
6965 		/*
6966 		 * We are here because we were told that the MAC label will
6967 		 * be transitioned, and the binary is not VSUID or VSGID; to
6968 		 * deal with this case, we could either duplicate a lot of
6969 		 * code, or we can indicate we want to default the P_SUGID
6970 		 * bit clear and jump back up.
6971 		 */
6972 		if (mac_transition) {
6973 			leave_sugid_clear = 1;
6974 			goto handle_mac_transition;
6975 		}
6976 	}
6977 
6978 #endif  /* CONFIG_MACF */
6979 
6980 	/* Update the process' identity version and set the security token.
6981 	 * Also, ensure we always see a modified identity version (rdar://129775819).
6982 	 */
6983 	int previous_pid_version = proc_get_ro(p)->p_idversion;
6984 	int new_pid_version;
6985 	do {
6986 		new_pid_version = OSIncrementAtomic(&nextpidversion);
6987 	} while (new_pid_version == previous_pid_version);
6988 	proc_setpidversion(p, new_pid_version);
6989 	task_set_uniqueid(proc_task(p));
6990 
6991 	/*
6992 	 * Implement the semantic where the effective user and group become
6993 	 * the saved user and group in exec'ed programs.
6994 	 */
6995 	kauth_cred_proc_update(p, PROC_SETTOKEN_ALWAYS,
6996 	    ^bool (kauth_cred_t parent __unused, kauth_cred_t model) {
6997 		posix_cred_t pcred = posix_cred_get(model);
6998 
6999 		if (pcred->cr_svuid == pcred->cr_uid &&
7000 		pcred->cr_svgid == pcred->cr_gid) {
7001 		        return false;
7002 		}
7003 
7004 		pcred->cr_svuid = pcred->cr_uid;
7005 		pcred->cr_svgid = pcred->cr_gid;
7006 		return true;
7007 	});
7008 
7009 	return error;
7010 }
7011 
7012 
7013 /*
7014  * create_unix_stack
7015  *
7016  * Description:	Set the user stack address for the process to the provided
7017  *		address.  If a custom stack was not set as a result of the
7018  *		load process (i.e. as specified by the image file for the
7019  *		executable), then allocate the stack in the provided map and
7020  *		set up appropriate guard pages for enforcing administrative
7021  *		limits on stack growth, if they end up being needed.
7022  *
7023  * Parameters:	p			Process to set stack on
7024  *		load_result		Information from mach-o load commands
7025  *		map			Address map in which to allocate the new stack
7026  *
7027  * Returns:	KERN_SUCCESS		Stack successfully created
7028  *		!KERN_SUCCESS		Mach failure code
7029  */
7030 __attribute__((noinline))
7031 static kern_return_t
create_unix_stack(vm_map_t map,load_result_t * load_result,proc_t p)7032 create_unix_stack(vm_map_t map, load_result_t* load_result,
7033     proc_t p)
7034 {
7035 	mach_vm_size_t          size, prot_size;
7036 	mach_vm_offset_t        addr, prot_addr;
7037 	kern_return_t           kr;
7038 
7039 	mach_vm_address_t       user_stack = load_result->user_stack;
7040 
7041 	proc_lock(p);
7042 	p->user_stack = (uintptr_t)user_stack;
7043 	if (load_result->custom_stack) {
7044 		p->p_lflag |= P_LCUSTOM_STACK;
7045 	}
7046 	proc_unlock(p);
7047 	if (vm_map_page_shift(map) < (int)PAGE_SHIFT) {
7048 		DEBUG4K_LOAD("map %p user_stack 0x%llx custom %d user_stack_alloc_size 0x%llx\n", map, user_stack, load_result->custom_stack, load_result->user_stack_alloc_size);
7049 	}
7050 
7051 	if (load_result->user_stack_alloc_size > 0) {
7052 		/*
7053 		 * Allocate enough space for the maximum stack size we
7054 		 * will ever authorize and an extra page to act as
7055 		 * a guard page for stack overflows. For default stacks,
7056 		 * vm_initial_limit_stack takes care of the extra guard page.
7057 		 * Otherwise we must allocate it ourselves.
7058 		 */
7059 		if (mach_vm_round_page_overflow(load_result->user_stack_alloc_size, &size)) {
7060 			return KERN_INVALID_ARGUMENT;
7061 		}
7062 		addr = vm_map_trunc_page(load_result->user_stack - size,
7063 		    vm_map_page_mask(map));
7064 		kr = mach_vm_allocate_kernel(map, &addr, size,
7065 		    VM_MAP_KERNEL_FLAGS_FIXED(.vm_tag = VM_MEMORY_STACK));
7066 		if (kr != KERN_SUCCESS) {
7067 			// Can't allocate at default location, try anywhere
7068 			addr = 0;
7069 			kr = mach_vm_allocate_kernel(map, &addr, size,
7070 			    VM_MAP_KERNEL_FLAGS_ANYWHERE(.vm_tag = VM_MEMORY_STACK));
7071 			if (kr != KERN_SUCCESS) {
7072 				return kr;
7073 			}
7074 
7075 			user_stack = addr + size;
7076 			load_result->user_stack = (user_addr_t)user_stack;
7077 
7078 			proc_lock(p);
7079 			p->user_stack = (uintptr_t)user_stack;
7080 			proc_unlock(p);
7081 		}
7082 
7083 		load_result->user_stack_alloc = (user_addr_t)addr;
7084 
7085 		/*
7086 		 * And prevent access to what's above the current stack
7087 		 * size limit for this process.
7088 		 */
7089 		if (load_result->user_stack_size == 0) {
7090 			load_result->user_stack_size = proc_limitgetcur(p, RLIMIT_STACK);
7091 			prot_size = vm_map_trunc_page(size - load_result->user_stack_size, vm_map_page_mask(map));
7092 		} else {
7093 			prot_size = PAGE_SIZE;
7094 		}
7095 
7096 		prot_addr = addr;
7097 		kr = mach_vm_protect(map,
7098 		    prot_addr,
7099 		    prot_size,
7100 		    FALSE,
7101 		    VM_PROT_NONE);
7102 		if (kr != KERN_SUCCESS) {
7103 			(void)mach_vm_deallocate(map, addr, size);
7104 			return kr;
7105 		}
7106 	}
7107 
7108 	return KERN_SUCCESS;
7109 }
7110 
7111 #include <sys/reboot.h>
7112 
7113 /*
7114  * load_init_program_at_path
7115  *
7116  * Description:	Load the "init" program; in most cases, this will be "launchd"
7117  *
7118  * Parameters:	p			Process to call execve() to create
7119  *					the "init" program
7120  *		scratch_addr		Page in p, scratch space
7121  *		path			NULL terminated path
7122  *
7123  * Returns:	KERN_SUCCESS		Success
7124  *		!KERN_SUCCESS           See execve/mac_execve for error codes
7125  *
7126  * Notes:	The process that is passed in is the first manufactured
7127  *		process on the system, and gets here via bsd_ast() firing
7128  *		for the first time.  This is done to ensure that bsd_init()
7129  *		has run to completion.
7130  *
7131  *		The address map of the first manufactured process matches the
7132  *		word width of the kernel. Once the self-exec completes, the
7133  *		initproc might be different.
7134  */
7135 static int
load_init_program_at_path(proc_t p,user_addr_t scratch_addr,const char * path)7136 load_init_program_at_path(proc_t p, user_addr_t scratch_addr, const char* path)
7137 {
7138 	int retval[2];
7139 	int error;
7140 	struct execve_args init_exec_args;
7141 	user_addr_t argv0 = USER_ADDR_NULL, argv1 = USER_ADDR_NULL;
7142 
7143 	/*
7144 	 * Validate inputs and pre-conditions
7145 	 */
7146 	assert(p);
7147 	assert(scratch_addr);
7148 	assert(path);
7149 
7150 	/*
7151 	 * Copy out program name.
7152 	 */
7153 	size_t path_length = strlen(path) + 1;
7154 	argv0 = scratch_addr;
7155 	error = copyout(path, argv0, path_length);
7156 	if (error) {
7157 		return error;
7158 	}
7159 
7160 	scratch_addr = USER_ADDR_ALIGN(scratch_addr + path_length, sizeof(user_addr_t));
7161 
7162 	/*
7163 	 * Put out first (and only) argument, similarly.
7164 	 * Assumes everything fits in a page as allocated above.
7165 	 */
7166 	if (boothowto & RB_SINGLE) {
7167 		const char *init_args = "-s";
7168 		size_t init_args_length = strlen(init_args) + 1;
7169 
7170 		argv1 = scratch_addr;
7171 		error = copyout(init_args, argv1, init_args_length);
7172 		if (error) {
7173 			return error;
7174 		}
7175 
7176 		scratch_addr = USER_ADDR_ALIGN(scratch_addr + init_args_length, sizeof(user_addr_t));
7177 	}
7178 
7179 	if (proc_is64bit(p)) {
7180 		user64_addr_t argv64bit[3] = {};
7181 
7182 		argv64bit[0] = argv0;
7183 		argv64bit[1] = argv1;
7184 		argv64bit[2] = USER_ADDR_NULL;
7185 
7186 		error = copyout(argv64bit, scratch_addr, sizeof(argv64bit));
7187 		if (error) {
7188 			return error;
7189 		}
7190 	} else {
7191 		user32_addr_t argv32bit[3] = {};
7192 
7193 		argv32bit[0] = (user32_addr_t)argv0;
7194 		argv32bit[1] = (user32_addr_t)argv1;
7195 		argv32bit[2] = USER_ADDR_NULL;
7196 
7197 		error = copyout(argv32bit, scratch_addr, sizeof(argv32bit));
7198 		if (error) {
7199 			return error;
7200 		}
7201 	}
7202 
7203 	/*
7204 	 * Set up argument block for fake call to execve.
7205 	 */
7206 	init_exec_args.fname = argv0;
7207 	init_exec_args.argp = scratch_addr;
7208 	init_exec_args.envp = USER_ADDR_NULL;
7209 
7210 	/*
7211 	 * So that init task is set with uid,gid 0 token
7212 	 *
7213 	 * The access to the cred is safe:
7214 	 * the proc isn't running yet, it's stable.
7215 	 */
7216 	set_security_token(p, proc_ucred_unsafe(p));
7217 
7218 	return execve(p, &init_exec_args, retval);
7219 }
7220 
7221 static const char * init_programs[] = {
7222 #if DEBUG
7223 	"/usr/appleinternal/sbin/launchd.debug",
7224 #endif
7225 #if DEVELOPMENT || DEBUG
7226 	"/usr/appleinternal/sbin/launchd.development",
7227 #endif
7228 	"/sbin/launchd",
7229 };
7230 
7231 /*
7232  * load_init_program
7233  *
7234  * Description:	Load the "init" program; in most cases, this will be "launchd"
7235  *
7236  * Parameters:	p			Process to call execve() to create
7237  *					the "init" program
7238  *
7239  * Returns:	(void)
7240  *
7241  * Notes:	The process that is passed in is the first manufactured
7242  *		process on the system, and gets here via bsd_ast() firing
7243  *		for the first time.  This is done to ensure that bsd_init()
7244  *		has run to completion.
7245  *
7246  *		In DEBUG & DEVELOPMENT builds, the launchdsuffix boot-arg
7247  *		may be used to select a specific launchd executable. As with
7248  *		the kcsuffix boot-arg, setting launchdsuffix to "" or "release"
7249  *		will force /sbin/launchd to be selected.
7250  *
7251  *              Search order by build:
7252  *
7253  * DEBUG	DEVELOPMENT	RELEASE		PATH
7254  * ----------------------------------------------------------------------------------
7255  * 1		1		NA		/usr/appleinternal/sbin/launchd.$LAUNCHDSUFFIX
7256  * 2		NA		NA		/usr/appleinternal/sbin/launchd.debug
7257  * 3		2		NA		/usr/appleinternal/sbin/launchd.development
7258  * 4		3		1		/sbin/launchd
7259  */
7260 void
load_init_program(proc_t p)7261 load_init_program(proc_t p)
7262 {
7263 	uint32_t i;
7264 	int error;
7265 	vm_map_t map = current_map();
7266 	mach_vm_offset_t scratch_addr = 0;
7267 	mach_vm_size_t map_page_size = vm_map_page_size(map);
7268 
7269 #if DEVELOPMENT || DEBUG
7270 	/* Use the opportunity to initialize exec's debug log stream */
7271 	exec_log_handle = os_log_create("com.apple.xnu.bsd", "exec");
7272 #endif /* DEVELOPMENT || DEBUG */
7273 
7274 	(void) mach_vm_allocate_kernel(map, &scratch_addr, map_page_size,
7275 	    VM_MAP_KERNEL_FLAGS_ANYWHERE());
7276 #if CONFIG_MEMORYSTATUS
7277 	(void) memorystatus_init_at_boot_snapshot();
7278 #endif /* CONFIG_MEMORYSTATUS */
7279 
7280 #if DEBUG || DEVELOPMENT
7281 	/* Check for boot-arg suffix first */
7282 	char launchd_suffix[64];
7283 	if (PE_parse_boot_argn("launchdsuffix", launchd_suffix, sizeof(launchd_suffix))) {
7284 		char launchd_path[128];
7285 		boolean_t is_release_suffix = ((launchd_suffix[0] == 0) ||
7286 		    (strcmp(launchd_suffix, "release") == 0));
7287 
7288 		if (is_release_suffix) {
7289 			printf("load_init_program: attempting to load /sbin/launchd\n");
7290 			error = load_init_program_at_path(p, (user_addr_t)scratch_addr, "/sbin/launchd");
7291 			if (!error) {
7292 				return;
7293 			}
7294 
7295 			panic("Process 1 exec of launchd.release failed, errno %d", error);
7296 		} else {
7297 			strlcpy(launchd_path, "/usr/appleinternal/sbin/launchd.", sizeof(launchd_path));
7298 			strlcat(launchd_path, launchd_suffix, sizeof(launchd_path));
7299 
7300 			printf("load_init_program: attempting to load %s\n", launchd_path);
7301 			error = load_init_program_at_path(p, (user_addr_t)scratch_addr, launchd_path);
7302 			if (!error) {
7303 				return;
7304 			} else if (error != ENOENT) {
7305 				printf("load_init_program: failed loading %s: errno %d\n", launchd_path, error);
7306 			}
7307 		}
7308 	}
7309 #endif
7310 
7311 	error = ENOENT;
7312 	for (i = 0; i < sizeof(init_programs) / sizeof(init_programs[0]); i++) {
7313 		printf("load_init_program: attempting to load %s\n", init_programs[i]);
7314 		error = load_init_program_at_path(p, (user_addr_t)scratch_addr, init_programs[i]);
7315 		if (!error) {
7316 			return;
7317 		} else if (error != ENOENT) {
7318 			printf("load_init_program: failed loading %s: errno %d\n", init_programs[i], error);
7319 		}
7320 	}
7321 
7322 	panic("Process 1 exec of %s failed, errno %d", ((i == 0) ? "<null>" : init_programs[i - 1]), error);
7323 }
7324 
7325 /*
7326  * load_return_to_errno
7327  *
7328  * Description:	Convert a load_return_t (Mach error) to an errno (BSD error)
7329  *
7330  * Parameters:	lrtn			Mach error number
7331  *
7332  * Returns:	(int)			BSD error number
7333  *		0			Success
7334  *		EBADARCH		Bad architecture
7335  *		EBADMACHO		Bad Mach object file
7336  *		ESHLIBVERS		Bad shared library version
7337  *		ENOMEM			Out of memory/resource shortage
7338  *		EACCES			Access denied
7339  *		ENOENT			Entry not found (usually "file does
7340  *					does not exist")
7341  *		EIO			An I/O error occurred
7342  *		EBADEXEC		The executable is corrupt/unknown
7343  */
7344 static int
load_return_to_errno(load_return_t lrtn)7345 load_return_to_errno(load_return_t lrtn)
7346 {
7347 	switch (lrtn) {
7348 	case LOAD_SUCCESS:
7349 		return 0;
7350 	case LOAD_BADARCH:
7351 		return EBADARCH;
7352 	case LOAD_BADMACHO:
7353 	case LOAD_BADMACHO_UPX:
7354 		return EBADMACHO;
7355 	case LOAD_SHLIB:
7356 		return ESHLIBVERS;
7357 	case LOAD_NOSPACE:
7358 	case LOAD_RESOURCE:
7359 		return ENOMEM;
7360 	case LOAD_PROTECT:
7361 		return EACCES;
7362 	case LOAD_ENOENT:
7363 		return ENOENT;
7364 	case LOAD_IOERROR:
7365 		return EIO;
7366 	case LOAD_DECRYPTFAIL:
7367 		return EAUTH;
7368 	case LOAD_FAILURE:
7369 	default:
7370 		return EBADEXEC;
7371 	}
7372 }
7373 
7374 #include <mach/mach_types.h>
7375 #include <mach/vm_prot.h>
7376 #include <mach/semaphore.h>
7377 #include <mach/sync_policy.h>
7378 #include <kern/clock.h>
7379 #include <mach/kern_return.h>
7380 
7381 /*
7382  * execargs_alloc
7383  *
7384  * Description:	Allocate the block of memory used by the execve arguments.
7385  *		At the same time, we allocate a page so that we can read in
7386  *		the first page of the image.
7387  *
7388  * Parameters:	struct image_params *	the image parameter block
7389  *
7390  * Returns:	0			Success
7391  *		EINVAL			Invalid argument
7392  *		EACCES			Permission denied
7393  *		EINTR			Interrupted function
7394  *		ENOMEM			Not enough space
7395  *
7396  * Notes:	This is a temporary allocation into the kernel address space
7397  *		to enable us to copy arguments in from user space.  This is
7398  *		necessitated by not mapping the process calling execve() into
7399  *		the kernel address space during the execve() system call.
7400  *
7401  *		We assemble the argument and environment, etc., into this
7402  *		region before copying it as a single block into the child
7403  *		process address space (at the top or bottom of the stack,
7404  *		depending on which way the stack grows; see the function
7405  *		exec_copyout_strings() for details).
7406  *
7407  *		This ends up with a second (possibly unnecessary) copy compared
7408  *		with assembing the data directly into the child address space,
7409  *		instead, but since we cannot be guaranteed that the parent has
7410  *		not modified its environment, we can't really know that it's
7411  *		really a block there as well.
7412  */
7413 
7414 
7415 static int execargs_waiters = 0;
7416 static LCK_MTX_DECLARE_ATTR(execargs_cache_lock, &proc_lck_grp, &proc_lck_attr);
7417 
7418 static void
execargs_lock_lock(void)7419 execargs_lock_lock(void)
7420 {
7421 	lck_mtx_lock_spin(&execargs_cache_lock);
7422 }
7423 
7424 static void
execargs_lock_unlock(void)7425 execargs_lock_unlock(void)
7426 {
7427 	lck_mtx_unlock(&execargs_cache_lock);
7428 }
7429 
7430 static wait_result_t
execargs_lock_sleep(void)7431 execargs_lock_sleep(void)
7432 {
7433 	return lck_mtx_sleep(&execargs_cache_lock, LCK_SLEEP_DEFAULT, &execargs_free_count, THREAD_INTERRUPTIBLE);
7434 }
7435 
7436 static kern_return_t
execargs_purgeable_allocate(char ** execarg_address)7437 execargs_purgeable_allocate(char **execarg_address)
7438 {
7439 	mach_vm_offset_t addr = 0;
7440 	kern_return_t kr = mach_vm_allocate_kernel(bsd_pageable_map, &addr,
7441 	    BSD_PAGEABLE_SIZE_PER_EXEC,
7442 	    VM_MAP_KERNEL_FLAGS_ANYWHERE(.vmf_purgeable = true));
7443 	*execarg_address = (char *)addr;
7444 	assert(kr == KERN_SUCCESS);
7445 	return kr;
7446 }
7447 
7448 static kern_return_t
execargs_purgeable_reference(void * execarg_address)7449 execargs_purgeable_reference(void *execarg_address)
7450 {
7451 	int state = VM_PURGABLE_NONVOLATILE;
7452 	kern_return_t kr = vm_map_purgable_control(bsd_pageable_map,
7453 	    (vm_offset_t) execarg_address, VM_PURGABLE_SET_STATE, &state);
7454 
7455 	assert(kr == KERN_SUCCESS);
7456 	return kr;
7457 }
7458 
7459 static kern_return_t
execargs_purgeable_volatilize(void * execarg_address)7460 execargs_purgeable_volatilize(void *execarg_address)
7461 {
7462 	int state = VM_PURGABLE_VOLATILE | VM_PURGABLE_ORDERING_OBSOLETE;
7463 	kern_return_t kr;
7464 	kr = vm_map_purgable_control(bsd_pageable_map,
7465 	    (vm_offset_t) execarg_address, VM_PURGABLE_SET_STATE, &state);
7466 
7467 	assert(kr == KERN_SUCCESS);
7468 
7469 	return kr;
7470 }
7471 
7472 static void
execargs_wakeup_waiters(void)7473 execargs_wakeup_waiters(void)
7474 {
7475 	thread_wakeup(&execargs_free_count);
7476 }
7477 
7478 static int
execargs_alloc(struct image_params * imgp)7479 execargs_alloc(struct image_params *imgp)
7480 {
7481 	kern_return_t kret;
7482 	wait_result_t res;
7483 	int i, cache_index = -1;
7484 
7485 	execargs_lock_lock();
7486 
7487 	while (execargs_free_count == 0) {
7488 		execargs_waiters++;
7489 		res = execargs_lock_sleep();
7490 		execargs_waiters--;
7491 		if (res != THREAD_AWAKENED) {
7492 			execargs_lock_unlock();
7493 			return EINTR;
7494 		}
7495 	}
7496 
7497 	execargs_free_count--;
7498 
7499 	for (i = 0; i < execargs_cache_size; i++) {
7500 		vm_offset_t element = execargs_cache[i];
7501 		if (element) {
7502 			cache_index = i;
7503 			imgp->ip_strings = (char *)(execargs_cache[i]);
7504 			execargs_cache[i] = 0;
7505 			break;
7506 		}
7507 	}
7508 
7509 	assert(execargs_free_count >= 0);
7510 
7511 	execargs_lock_unlock();
7512 
7513 	if (cache_index == -1) {
7514 		kret = execargs_purgeable_allocate(&imgp->ip_strings);
7515 	} else {
7516 		kret = execargs_purgeable_reference(imgp->ip_strings);
7517 	}
7518 
7519 	assert(kret == KERN_SUCCESS);
7520 	if (kret != KERN_SUCCESS) {
7521 		return ENOMEM;
7522 	}
7523 
7524 	/* last page used to read in file headers */
7525 	imgp->ip_vdata = imgp->ip_strings + (NCARGS + PAGE_SIZE);
7526 	imgp->ip_strendp = imgp->ip_strings;
7527 	imgp->ip_argspace = NCARGS;
7528 	imgp->ip_strspace = (NCARGS + PAGE_SIZE);
7529 
7530 	return 0;
7531 }
7532 
7533 /*
7534  * execargs_free
7535  *
7536  * Description:	Free the block of memory used by the execve arguments and the
7537  *		first page of the executable by a previous call to the function
7538  *		execargs_alloc().
7539  *
7540  * Parameters:	struct image_params *	the image parameter block
7541  *
7542  * Returns:	0			Success
7543  *		EINVAL			Invalid argument
7544  *		EINTR			Oeration interrupted
7545  */
7546 static int
execargs_free(struct image_params * imgp)7547 execargs_free(struct image_params *imgp)
7548 {
7549 	kern_return_t kret;
7550 	int i;
7551 	boolean_t needs_wakeup = FALSE;
7552 
7553 	kret = execargs_purgeable_volatilize(imgp->ip_strings);
7554 
7555 	execargs_lock_lock();
7556 	execargs_free_count++;
7557 
7558 	for (i = 0; i < execargs_cache_size; i++) {
7559 		vm_offset_t element = execargs_cache[i];
7560 		if (element == 0) {
7561 			execargs_cache[i] = (vm_offset_t) imgp->ip_strings;
7562 			imgp->ip_strings = NULL;
7563 			break;
7564 		}
7565 	}
7566 
7567 	assert(imgp->ip_strings == NULL);
7568 
7569 	if (execargs_waiters > 0) {
7570 		needs_wakeup = TRUE;
7571 	}
7572 
7573 	execargs_lock_unlock();
7574 
7575 	if (needs_wakeup == TRUE) {
7576 		execargs_wakeup_waiters();
7577 	}
7578 
7579 	return kret == KERN_SUCCESS ? 0 : EINVAL;
7580 }
7581 
7582 void
uthread_set_exec_data(struct uthread * uth,struct image_params * imgp)7583 uthread_set_exec_data(struct uthread *uth, struct image_params *imgp)
7584 {
7585 	uth->uu_save.uus_exec_data.imgp = imgp;
7586 }
7587 
7588 size_t
thread_get_current_exec_path(char * path,size_t size)7589 thread_get_current_exec_path(char *path, size_t size)
7590 {
7591 	struct uthread *uth = current_uthread();
7592 	struct image_params *imgp = uth->uu_save.uus_exec_data.imgp;
7593 	size_t string_size = 0;
7594 	char *exec_path;
7595 
7596 	if (path == NULL || imgp == NULL || imgp->ip_strings == NULL) {
7597 		return 0;
7598 	}
7599 
7600 	exec_path = imgp->ip_strings + strlen(EXECUTABLE_KEY);
7601 	string_size = imgp->ip_strendp - exec_path;
7602 	string_size = MIN(MAXPATHLEN, string_size);
7603 	string_size = MIN(size, string_size);
7604 
7605 	string_size = strlcpy(path, exec_path, string_size);
7606 	return string_size;
7607 }
7608 static void
exec_resettextvp(proc_t p,struct image_params * imgp)7609 exec_resettextvp(proc_t p, struct image_params *imgp)
7610 {
7611 	vnode_t vp;
7612 	off_t offset;
7613 	vnode_t tvp  = p->p_textvp;
7614 	int ret;
7615 
7616 	vp = imgp->ip_vp;
7617 	offset = imgp->ip_arch_offset;
7618 
7619 	if (vp == NULLVP) {
7620 		panic("exec_resettextvp: expected valid vp");
7621 	}
7622 
7623 	ret = vnode_ref(vp);
7624 	proc_lock(p);
7625 	if (ret == 0) {
7626 		p->p_textvp = vp;
7627 		p->p_textoff = offset;
7628 	} else {
7629 		p->p_textvp = NULLVP;   /* this is paranoia */
7630 		p->p_textoff = 0;
7631 	}
7632 	proc_unlock(p);
7633 
7634 	if (tvp != NULLVP) {
7635 		if (vnode_getwithref(tvp) == 0) {
7636 			vnode_rele(tvp);
7637 			vnode_put(tvp);
7638 		}
7639 	}
7640 }
7641 
7642 // Includes the 0-byte (therefore "SIZE" instead of "LEN").
7643 static const size_t CS_CDHASH_STRING_SIZE = CS_CDHASH_LEN * 2 + 1;
7644 
7645 static void
cdhash_to_string(char str[CS_CDHASH_STRING_SIZE],uint8_t const * const cdhash)7646 cdhash_to_string(char str[CS_CDHASH_STRING_SIZE], uint8_t const * const cdhash)
7647 {
7648 	static char const nibble[] = "0123456789abcdef";
7649 
7650 	/* Apparently still the safest way to get a hex representation
7651 	 * of binary data.
7652 	 * xnu's printf routines have %*D/%20D in theory, but "not really", see:
7653 	 * <rdar://problem/33328859> confusion around %*D/%nD in printf
7654 	 */
7655 	for (int i = 0; i < CS_CDHASH_LEN; ++i) {
7656 		str[i * 2] = nibble[(cdhash[i] & 0xf0) >> 4];
7657 		str[i * 2 + 1] = nibble[cdhash[i] & 0x0f];
7658 	}
7659 	str[CS_CDHASH_STRING_SIZE - 1] = 0;
7660 }
7661 
7662 /*
7663  * __EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__
7664  *
7665  * Description: Waits for the userspace daemon to respond to the request
7666  *              we made. Function declared non inline to be visible in
7667  *		stackshots and spindumps as well as debugging.
7668  */
7669 __attribute__((noinline)) int
__EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__(mach_port_t task_access_port,int32_t new_pid)7670 __EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__(mach_port_t task_access_port, int32_t new_pid)
7671 {
7672 	return find_code_signature(task_access_port, new_pid);
7673 }
7674 
7675 /*
7676  * Update signature dependent process state, called by
7677  * process_signature.
7678  */
7679 static int
proc_process_signature(proc_t p,os_reason_t * signature_failure_reason)7680 proc_process_signature(proc_t p, os_reason_t *signature_failure_reason)
7681 {
7682 	int error = 0;
7683 	char const *error_msg = NULL;
7684 
7685 	kern_return_t kr = machine_task_process_signature(proc_get_task_raw(p), proc_platform(p), proc_sdk(p), &error_msg);
7686 
7687 	if (kr != KERN_SUCCESS) {
7688 		error = EINVAL;
7689 
7690 		if (error_msg != NULL) {
7691 			uint32_t error_msg_len = (uint32_t)strlen(error_msg) + 1;
7692 			mach_vm_address_t data_addr = 0;
7693 			int reason_error = 0;
7694 			int kcdata_error = 0;
7695 
7696 			os_reason_t reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_SECURITY_POLICY);
7697 			reason->osr_flags = OS_REASON_FLAG_GENERATE_CRASH_REPORT | OS_REASON_FLAG_CONSISTENT_FAILURE;
7698 
7699 			if ((reason_error = os_reason_alloc_buffer_noblock(reason,
7700 			    kcdata_estimate_required_buffer_size(1, error_msg_len))) == 0 &&
7701 			    (kcdata_error = kcdata_get_memory_addr(&reason->osr_kcd_descriptor,
7702 			    EXIT_REASON_USER_DESC, error_msg_len,
7703 			    &data_addr)) == KERN_SUCCESS) {
7704 				kern_return_t mc_error = kcdata_memcpy(&reason->osr_kcd_descriptor, (mach_vm_address_t)data_addr,
7705 				    error_msg, error_msg_len);
7706 
7707 				if (mc_error != KERN_SUCCESS) {
7708 					printf("process_signature: failed to copy reason string (kcdata_memcpy error: %d)\n",
7709 					    mc_error);
7710 				}
7711 			} else {
7712 				printf("failed to allocate space for reason string (os_reason_alloc_buffer error: %d, kcdata error: %d, length: %u)\n",
7713 				    reason_error, kcdata_error, error_msg_len);
7714 			}
7715 
7716 			assert(*signature_failure_reason == NULL); // shouldn't have gotten so far
7717 			*signature_failure_reason = reason;
7718 		}
7719 	}
7720 	return error;
7721 }
7722 
7723 #define DT_UNRESTRICTED_SUBSYSTEM_ROOT "unrestricted-subsystem-root"
7724 
7725 static bool
allow_unrestricted_subsystem_root(void)7726 allow_unrestricted_subsystem_root(void)
7727 {
7728 #if !(DEVELOPMENT || DEBUG)
7729 	static bool allow_unrestricted_subsystem_root = false;
7730 	static bool has_been_set = false;
7731 
7732 	if (!has_been_set) {
7733 		DTEntry chosen;
7734 		const uint32_t *value;
7735 		unsigned size;
7736 
7737 		has_been_set = true;
7738 		if (SecureDTLookupEntry(0, "/chosen", &chosen) == kSuccess &&
7739 		    SecureDTGetProperty(chosen, DT_UNRESTRICTED_SUBSYSTEM_ROOT, (const void**)&value, &size) == kSuccess &&
7740 		    value != NULL &&
7741 		    size == sizeof(uint32_t)) {
7742 			allow_unrestricted_subsystem_root = (bool)*value;
7743 		}
7744 	}
7745 
7746 	return allow_unrestricted_subsystem_root;
7747 #else
7748 	return true;
7749 #endif
7750 }
7751 
7752 static int
process_signature(proc_t p,struct image_params * imgp)7753 process_signature(proc_t p, struct image_params *imgp)
7754 {
7755 	mach_port_t port = IPC_PORT_NULL;
7756 	kern_return_t kr = KERN_FAILURE;
7757 	int error = EACCES;
7758 	boolean_t unexpected_failure = FALSE;
7759 	struct cs_blob *csb;
7760 	boolean_t require_success = FALSE;
7761 	int spawn = (imgp->ip_flags & IMGPF_SPAWN);
7762 	const int vfexec = 0;
7763 	os_reason_t signature_failure_reason = OS_REASON_NULL;
7764 
7765 	/*
7766 	 * Override inherited code signing flags with the
7767 	 * ones for the process that is being successfully
7768 	 * loaded
7769 	 */
7770 	proc_lock(p);
7771 	proc_csflags_update(p, imgp->ip_csflags);
7772 	proc_unlock(p);
7773 
7774 	/* Set the switch_protect flag on the map */
7775 	if (proc_getcsflags(p) & (CS_HARD | CS_KILL)) {
7776 		vm_map_switch_protect(get_task_map(proc_task(p)), TRUE);
7777 	}
7778 	/* set the cs_enforced flags in the map */
7779 	if (proc_getcsflags(p) & CS_ENFORCEMENT) {
7780 		vm_map_cs_enforcement_set(get_task_map(proc_task(p)), TRUE);
7781 	} else {
7782 		vm_map_cs_enforcement_set(get_task_map(proc_task(p)), FALSE);
7783 	}
7784 
7785 	/*
7786 	 * image activation may be failed due to policy
7787 	 * which is unexpected but security framework does not
7788 	 * approve of exec, kill and return immediately.
7789 	 */
7790 	if (imgp->ip_mac_return != 0) {
7791 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
7792 		    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_SECURITY_POLICY, 0, 0);
7793 		signature_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_SECURITY_POLICY);
7794 		error = imgp->ip_mac_return;
7795 		unexpected_failure = TRUE;
7796 		goto done;
7797 	}
7798 
7799 	if (imgp->ip_cs_error != OS_REASON_NULL) {
7800 		signature_failure_reason = imgp->ip_cs_error;
7801 		imgp->ip_cs_error = OS_REASON_NULL;
7802 		error = EACCES;
7803 		goto done;
7804 	}
7805 
7806 	/* call the launch constraints hook */
7807 	os_reason_t launch_constraint_reason;
7808 	if ((error = mac_proc_check_launch_constraints(p, imgp, &launch_constraint_reason)) != 0) {
7809 		signature_failure_reason = launch_constraint_reason;
7810 		goto done;
7811 	}
7812 
7813 	/*
7814 	 * Reject when there's subsystem root path set, but the image is restricted, and doesn't require
7815 	 * library validation. This is to avoid subsystem root being used to inject unsigned code
7816 	 */
7817 	if (!allow_unrestricted_subsystem_root()) {
7818 		if ((imgp->ip_csflags & CS_RESTRICT || proc_issetugid(p)) &&
7819 		    !(imgp->ip_csflags & CS_REQUIRE_LV) &&
7820 		    (imgp->ip_subsystem_root_path != NULL)) {
7821 			signature_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_SECURITY_POLICY);
7822 			error = EACCES;
7823 			goto done;
7824 		}
7825 	}
7826 
7827 #if XNU_TARGET_OS_OSX
7828 	/* Check for platform passed in spawn attr if iOS binary is being spawned */
7829 	if (proc_platform(p) == PLATFORM_IOS) {
7830 		struct _posix_spawnattr *psa = (struct _posix_spawnattr *) imgp->ip_px_sa;
7831 		if (psa == NULL || psa->psa_platform == 0) {
7832 			boolean_t no_sandbox_entitled = FALSE;
7833 #if DEBUG || DEVELOPMENT
7834 			/*
7835 			 * Allow iOS binaries to spawn on internal systems
7836 			 * if no-sandbox entitlement is present of unentitled_ios_sim_launch
7837 			 * boot-arg set to true
7838 			 */
7839 			if (unentitled_ios_sim_launch) {
7840 				no_sandbox_entitled = TRUE;
7841 			} else {
7842 				no_sandbox_entitled = IOVnodeHasEntitlement(imgp->ip_vp,
7843 				    (int64_t)imgp->ip_arch_offset, "com.apple.private.security.no-sandbox");
7844 			}
7845 #endif /* DEBUG || DEVELOPMENT */
7846 			if (!no_sandbox_entitled) {
7847 				signature_failure_reason = os_reason_create(OS_REASON_EXEC,
7848 				    EXEC_EXIT_REASON_WRONG_PLATFORM);
7849 				error = EACCES;
7850 				goto done;
7851 			}
7852 			printf("Allowing spawn of iOS binary %s since it has "
7853 			    "com.apple.private.security.no-sandbox entitlement or unentitled_ios_sim_launch "
7854 			    "boot-arg set to true\n", p->p_name);
7855 		} else if (psa->psa_platform != PLATFORM_IOS) {
7856 			/* Simulator binary spawned with wrong platform */
7857 			signature_failure_reason = os_reason_create(OS_REASON_EXEC,
7858 			    EXEC_EXIT_REASON_WRONG_PLATFORM);
7859 			error = EACCES;
7860 			goto done;
7861 		} else {
7862 			printf("Allowing spawn of iOS binary %s since correct platform was passed in spawn\n",
7863 			    p->p_name);
7864 		}
7865 	}
7866 #endif /* XNU_TARGET_OS_OSX */
7867 
7868 	/* If the code signature came through the image activation path, we skip the
7869 	 * taskgated / externally attached path. */
7870 	if (imgp->ip_csflags & CS_SIGNED) {
7871 		error = 0;
7872 		goto done;
7873 	}
7874 
7875 	/* The rest of the code is for signatures that either already have been externally
7876 	 * attached (likely, but not necessarily by a previous run through the taskgated
7877 	 * path), or that will now be attached by taskgated. */
7878 
7879 	kr = task_get_task_access_port(proc_task(p), &port);
7880 	if (KERN_SUCCESS != kr || !IPC_PORT_VALID(port)) {
7881 		error = 0;
7882 		if (require_success) {
7883 			KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
7884 			    proc_getpid(p), OS_REASON_CODESIGNING, CODESIGNING_EXIT_REASON_TASK_ACCESS_PORT, 0, 0);
7885 			signature_failure_reason = os_reason_create(OS_REASON_CODESIGNING, CODESIGNING_EXIT_REASON_TASK_ACCESS_PORT);
7886 			error = EACCES;
7887 		}
7888 		goto done;
7889 	}
7890 
7891 	/*
7892 	 * taskgated returns KERN_SUCCESS if it has completed its work
7893 	 * and the exec should continue, KERN_FAILURE if the exec should
7894 	 * fail, or it may error out with different error code in an
7895 	 * event of mig failure (e.g. process was signalled during the
7896 	 * rpc call, taskgated died, mig server died etc.).
7897 	 */
7898 
7899 	kr = __EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__(port, proc_getpid(p));
7900 	switch (kr) {
7901 	case KERN_SUCCESS:
7902 		error = 0;
7903 		break;
7904 	case KERN_FAILURE:
7905 		error = EACCES;
7906 
7907 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
7908 		    proc_getpid(p), OS_REASON_CODESIGNING, CODESIGNING_EXIT_REASON_TASKGATED_INVALID_SIG, 0, 0);
7909 		signature_failure_reason = os_reason_create(OS_REASON_CODESIGNING, CODESIGNING_EXIT_REASON_TASKGATED_INVALID_SIG);
7910 		goto done;
7911 	default:
7912 		error = EACCES;
7913 
7914 		KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE,
7915 		    proc_getpid(p), OS_REASON_EXEC, EXEC_EXIT_REASON_TASKGATED_OTHER, 0, 0);
7916 		signature_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_TASKGATED_OTHER);
7917 		unexpected_failure = TRUE;
7918 		goto done;
7919 	}
7920 
7921 	/* Only do this if exec_resettextvp() did not fail */
7922 	if (p->p_textvp != NULLVP) {
7923 		csb = ubc_cs_blob_get(p->p_textvp, -1, -1, p->p_textoff);
7924 
7925 		if (csb != NULL) {
7926 			/* As the enforcement we can do here is very limited, we only allow things that
7927 			 * are the only reason why this code path still exists:
7928 			 * Adhoc signed non-platform binaries without special cs_flags and without any
7929 			 * entitlements (unrestricted ones still pass AMFI). */
7930 			if (
7931 				/* Revalidate the blob if necessary through bumped generation count. */
7932 				(ubc_cs_generation_check(p->p_textvp) == 0 ||
7933 				ubc_cs_blob_revalidate(p->p_textvp, csb, imgp, 0, proc_platform(p)) == 0) &&
7934 				/* Only CS_ADHOC, no CS_KILL, CS_HARD etc. */
7935 				(csb->csb_flags & CS_ALLOWED_MACHO) == CS_ADHOC &&
7936 				/* If it has a CMS blob, it's not adhoc. The CS_ADHOC flag can lie. */
7937 				csblob_find_blob_bytes((const uint8_t *)csb->csb_mem_kaddr, csb->csb_mem_size,
7938 				CSSLOT_SIGNATURESLOT,
7939 				CSMAGIC_BLOBWRAPPER) == NULL &&
7940 				/* It could still be in a trust cache (unlikely with CS_ADHOC), or a magic path. */
7941 				csb->csb_platform_binary == 0 &&
7942 				/* No entitlements, not even unrestricted ones. */
7943 				csb->csb_entitlements_blob == NULL &&
7944 				csb->csb_der_entitlements_blob == NULL) {
7945 				proc_lock(p);
7946 				proc_csflags_set(p, CS_SIGNED | CS_VALID);
7947 				proc_unlock(p);
7948 			} else {
7949 				uint8_t cdhash[CS_CDHASH_LEN];
7950 				char cdhash_string[CS_CDHASH_STRING_SIZE];
7951 				proc_getcdhash(p, cdhash);
7952 				cdhash_to_string(cdhash_string, cdhash);
7953 				printf("ignoring detached code signature on '%s' with cdhash '%s' "
7954 				    "because it is invalid, or not a simple adhoc signature.\n",
7955 				    p->p_name, cdhash_string);
7956 			}
7957 		}
7958 	}
7959 
7960 done:
7961 	if (0 == error) {
7962 		/*
7963 		 * Update the new process's signature-dependent process state.
7964 		 * state.
7965 		 */
7966 
7967 		error = proc_process_signature(p, &signature_failure_reason);
7968 	}
7969 
7970 	if (0 == error) {
7971 		/*
7972 		 * Update the new main thread's signature-dependent thread
7973 		 * state. This was also called when the thread was created,
7974 		 * but for the main thread the signature was not yet attached
7975 		 * at that time.
7976 		 */
7977 		kr = thread_process_signature(imgp->ip_new_thread, proc_get_task_raw(p));
7978 
7979 		if (kr != KERN_SUCCESS) {
7980 			error = EINVAL;
7981 			signature_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_MACHINE_THREAD);
7982 		}
7983 	}
7984 
7985 	if (0 == error) {
7986 		/* The process's code signature related properties are
7987 		 * fully set up, so this is an opportune moment to log
7988 		 * platform binary execution, if desired. */
7989 		if (platform_exec_logging != 0 && csproc_get_platform_binary(p)) {
7990 			uint8_t cdhash[CS_CDHASH_LEN];
7991 			char cdhash_string[CS_CDHASH_STRING_SIZE];
7992 			proc_getcdhash(p, cdhash);
7993 			cdhash_to_string(cdhash_string, cdhash);
7994 
7995 			os_log(peLog, "CS Platform Exec Logging: Executing platform signed binary "
7996 			    "'%s' with cdhash %s\n", p->p_name, cdhash_string);
7997 		}
7998 	} else {
7999 		if (!unexpected_failure) {
8000 			proc_csflags_set(p, CS_KILLED);
8001 		}
8002 		/* make very sure execution fails */
8003 		if (vfexec || spawn) {
8004 			assert(signature_failure_reason != OS_REASON_NULL);
8005 			psignal_vfork_with_reason(p, proc_task(p), imgp->ip_new_thread,
8006 			    SIGKILL, signature_failure_reason);
8007 			signature_failure_reason = OS_REASON_NULL;
8008 			error = 0;
8009 		} else {
8010 			assert(signature_failure_reason != OS_REASON_NULL);
8011 			psignal_with_reason(p, SIGKILL, signature_failure_reason);
8012 			signature_failure_reason = OS_REASON_NULL;
8013 		}
8014 	}
8015 
8016 	if (port != IPC_PORT_NULL) {
8017 		ipc_port_release_send(port);
8018 	}
8019 
8020 	/* If we hit this, we likely would have leaked an exit reason */
8021 	assert(signature_failure_reason == OS_REASON_NULL);
8022 	return error;
8023 }
8024 
8025 /*
8026  * Typically as soon as we start executing this process, the
8027  * first instruction will trigger a VM fault to bring the text
8028  * pages (as executable) into the address space, followed soon
8029  * thereafter by dyld data structures (for dynamic executable).
8030  * To optimize this, as well as improve support for hardware
8031  * debuggers that can only access resident pages present
8032  * in the process' page tables, we prefault some pages if
8033  * possible. Errors are non-fatal.
8034  */
8035 #ifndef PREVENT_CALLER_STACK_USE
8036 #define PREVENT_CALLER_STACK_USE __attribute__((noinline))
8037 #endif
8038 
8039 /*
8040  * Prefaulting dyld data does not work (rdar://76621401)
8041  */
8042 #define FIXED_76621401 0
8043 static void PREVENT_CALLER_STACK_USE
exec_prefault_data(__unused proc_t p,__unused struct image_params * imgp,__unused load_result_t * load_result)8044 exec_prefault_data(
8045 	__unused proc_t p,
8046 	__unused struct image_params *imgp,
8047 	__unused load_result_t *load_result)
8048 {
8049 #if FIXED_76621401
8050 	int ret;
8051 	size_t expected_all_image_infos_size;
8052 #endif /* FIXED_76621401 */
8053 	kern_return_t kr;
8054 
8055 	/*
8056 	 * Prefault executable or dyld entry point.
8057 	 */
8058 	if (vm_map_page_shift(current_map()) < (int)PAGE_SHIFT) {
8059 		DEBUG4K_LOAD("entry_point 0x%llx\n", (uint64_t)load_result->entry_point);
8060 	}
8061 	kr = vm_fault(current_map(),
8062 	    vm_map_trunc_page(load_result->entry_point,
8063 	    vm_map_page_mask(current_map())),
8064 	    VM_PROT_READ | VM_PROT_EXECUTE,
8065 	    FALSE, VM_KERN_MEMORY_NONE,
8066 	    THREAD_UNINT, NULL, 0);
8067 	if (kr != KERN_SUCCESS) {
8068 		DEBUG4K_ERROR("map %p va 0x%llx -> 0x%x\n", current_map(), (uint64_t)vm_map_trunc_page(load_result->entry_point, vm_map_page_mask(current_map())), kr);
8069 	}
8070 
8071 #if FIXED_76621401
8072 	if (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) {
8073 		expected_all_image_infos_size = sizeof(struct user64_dyld_all_image_infos);
8074 	} else {
8075 		expected_all_image_infos_size = sizeof(struct user32_dyld_all_image_infos);
8076 	}
8077 
8078 	/* Decode dyld anchor structure from <mach-o/dyld_images.h> */
8079 	if (load_result->dynlinker &&
8080 	    load_result->all_image_info_addr &&
8081 	    load_result->all_image_info_size >= expected_all_image_infos_size) {
8082 		union {
8083 			struct user64_dyld_all_image_infos      infos64;
8084 			struct user32_dyld_all_image_infos      infos32;
8085 		} all_image_infos;
8086 
8087 		/*
8088 		 * Pre-fault to avoid copyin() going through the trap handler
8089 		 * and recovery path.
8090 		 */
8091 		if (vm_map_page_shift(current_map()) < (int)PAGE_SHIFT) {
8092 			DEBUG4K_LOAD("all_image_info_addr 0x%llx\n", load_result->all_image_info_addr);
8093 		}
8094 		kr = vm_fault(current_map(),
8095 		    vm_map_trunc_page(load_result->all_image_info_addr,
8096 		    vm_map_page_mask(current_map())),
8097 		    VM_PROT_READ | VM_PROT_WRITE,
8098 		    FALSE, VM_KERN_MEMORY_NONE,
8099 		    THREAD_UNINT, NULL, 0);
8100 		if (kr != KERN_SUCCESS) {
8101 //			printf("%s:%d map %p va 0x%llx -> 0x%x\n", __FUNCTION__, __LINE__, current_map(), vm_map_trunc_page(load_result->all_image_info_addr, vm_map_page_mask(current_map())), kr);
8102 		}
8103 		if ((load_result->all_image_info_addr & PAGE_MASK) + expected_all_image_infos_size > PAGE_SIZE) {
8104 			/* all_image_infos straddles a page */
8105 			kr = vm_fault(current_map(),
8106 			    vm_map_trunc_page(load_result->all_image_info_addr + expected_all_image_infos_size - 1,
8107 			    vm_map_page_mask(current_map())),
8108 			    VM_PROT_READ | VM_PROT_WRITE,
8109 			    FALSE, VM_KERN_MEMORY_NONE,
8110 			    THREAD_UNINT, NULL, 0);
8111 			if (kr != KERN_SUCCESS) {
8112 //				printf("%s:%d map %p va 0x%llx -> 0x%x\n", __FUNCTION__, __LINE__, current_map(), vm_map_trunc_page(load_result->all_image_info_addr + expected_all_image_infos_size -1, vm_map_page_mask(current_map())), kr);
8113 			}
8114 		}
8115 
8116 		if (vm_map_page_shift(current_map()) < (int)PAGE_SHIFT) {
8117 			DEBUG4K_LOAD("copyin(0x%llx, 0x%lx)\n", load_result->all_image_info_addr, expected_all_image_infos_size);
8118 		}
8119 		ret = copyin((user_addr_t)load_result->all_image_info_addr,
8120 		    &all_image_infos,
8121 		    expected_all_image_infos_size);
8122 		if (ret == 0 && all_image_infos.infos32.version >= DYLD_ALL_IMAGE_INFOS_ADDRESS_MINIMUM_VERSION) {
8123 			user_addr_t notification_address;
8124 			user_addr_t dyld_image_address;
8125 			user_addr_t dyld_version_address;
8126 			user_addr_t dyld_all_image_infos_address;
8127 			user_addr_t dyld_slide_amount;
8128 
8129 			if (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) {
8130 				notification_address = (user_addr_t)all_image_infos.infos64.notification;
8131 				dyld_image_address = (user_addr_t)all_image_infos.infos64.dyldImageLoadAddress;
8132 				dyld_version_address = (user_addr_t)all_image_infos.infos64.dyldVersion;
8133 				dyld_all_image_infos_address = (user_addr_t)all_image_infos.infos64.dyldAllImageInfosAddress;
8134 			} else {
8135 				notification_address = all_image_infos.infos32.notification;
8136 				dyld_image_address = all_image_infos.infos32.dyldImageLoadAddress;
8137 				dyld_version_address = all_image_infos.infos32.dyldVersion;
8138 				dyld_all_image_infos_address = all_image_infos.infos32.dyldAllImageInfosAddress;
8139 			}
8140 
8141 			/*
8142 			 * dyld statically sets up the all_image_infos in its Mach-O
8143 			 * binary at static link time, with pointers relative to its default
8144 			 * load address. Since ASLR might slide dyld before its first
8145 			 * instruction is executed, "dyld_slide_amount" tells us how far
8146 			 * dyld was loaded compared to its default expected load address.
8147 			 * All other pointers into dyld's image should be adjusted by this
8148 			 * amount. At some point later, dyld will fix up pointers to take
8149 			 * into account the slide, at which point the all_image_infos_address
8150 			 * field in the structure will match the runtime load address, and
8151 			 * "dyld_slide_amount" will be 0, if we were to consult it again.
8152 			 */
8153 
8154 			dyld_slide_amount = (user_addr_t)load_result->all_image_info_addr - dyld_all_image_infos_address;
8155 
8156 #if 0
8157 			kprintf("exec_prefault: 0x%016llx 0x%08x 0x%016llx 0x%016llx 0x%016llx 0x%016llx\n",
8158 			    (uint64_t)load_result->all_image_info_addr,
8159 			    all_image_infos.infos32.version,
8160 			    (uint64_t)notification_address,
8161 			    (uint64_t)dyld_image_address,
8162 			    (uint64_t)dyld_version_address,
8163 			    (uint64_t)dyld_all_image_infos_address);
8164 #endif
8165 
8166 			if (vm_map_page_shift(current_map()) < (int)PAGE_SHIFT) {
8167 				DEBUG4K_LOAD("notification_address 0x%llx dyld_slide_amount 0x%llx\n", (uint64_t)notification_address, (uint64_t)dyld_slide_amount);
8168 			}
8169 			kr = vm_fault(current_map(),
8170 			    vm_map_trunc_page(notification_address + dyld_slide_amount,
8171 			    vm_map_page_mask(current_map())),
8172 			    VM_PROT_READ | VM_PROT_EXECUTE,
8173 			    FALSE, VM_KERN_MEMORY_NONE,
8174 			    THREAD_UNINT, NULL, 0);
8175 			if (kr != KERN_SUCCESS) {
8176 //				printf("%s:%d map %p va 0x%llx -> 0x%x\n", __FUNCTION__, __LINE__, current_map(), vm_map_trunc_page(notification_address + dyld_slide_amount, vm_map_page_mask(current_map())), kr);
8177 			}
8178 			if (vm_map_page_shift(current_map()) < (int)PAGE_SHIFT) {
8179 				DEBUG4K_LOAD("dyld_image_address 0x%llx dyld_slide_amount 0x%llx\n", (uint64_t)dyld_image_address, (uint64_t)dyld_slide_amount);
8180 			}
8181 			kr = vm_fault(current_map(),
8182 			    vm_map_trunc_page(dyld_image_address + dyld_slide_amount,
8183 			    vm_map_page_mask(current_map())),
8184 			    VM_PROT_READ | VM_PROT_EXECUTE,
8185 			    FALSE, VM_KERN_MEMORY_NONE,
8186 			    THREAD_UNINT, NULL, 0);
8187 			if (kr != KERN_SUCCESS) {
8188 //				printf("%s:%d map %p va 0x%llx -> 0x%x\n", __FUNCTION__, __LINE__, current_map(), vm_map_trunc_page(dyld_image_address + dyld_slide_amount, vm_map_page_mask(current_map())), kr);
8189 			}
8190 			if (vm_map_page_shift(current_map()) < (int)PAGE_SHIFT) {
8191 				DEBUG4K_LOAD("dyld_version_address 0x%llx dyld_slide_amount 0x%llx\n", (uint64_t)dyld_version_address, (uint64_t)dyld_slide_amount);
8192 			}
8193 			kr = vm_fault(current_map(),
8194 			    vm_map_trunc_page(dyld_version_address + dyld_slide_amount,
8195 			    vm_map_page_mask(current_map())),
8196 			    VM_PROT_READ,
8197 			    FALSE, VM_KERN_MEMORY_NONE,
8198 			    THREAD_UNINT, NULL, 0);
8199 			if (kr != KERN_SUCCESS) {
8200 //				printf("%s:%d map %p va 0x%llx -> 0x%x\n", __FUNCTION__, __LINE__, current_map(), vm_map_trunc_page(dyld_version_address + dyld_slide_amount, vm_map_page_mask(current_map())), kr);
8201 			}
8202 			if (vm_map_page_shift(current_map()) < (int)PAGE_SHIFT) {
8203 				DEBUG4K_LOAD("dyld_all_image_infos_address 0x%llx dyld_slide_amount 0x%llx\n", (uint64_t)dyld_version_address, (uint64_t)dyld_slide_amount);
8204 			}
8205 			kr = vm_fault(current_map(),
8206 			    vm_map_trunc_page(dyld_all_image_infos_address + dyld_slide_amount,
8207 			    vm_map_page_mask(current_map())),
8208 			    VM_PROT_READ | VM_PROT_WRITE,
8209 			    FALSE, VM_KERN_MEMORY_NONE,
8210 			    THREAD_UNINT, NULL, 0);
8211 			if (kr != KERN_SUCCESS) {
8212 //				printf("%s:%d map %p va 0x%llx -> 0x%x\n", __FUNCTION__, __LINE__, current_map(), vm_map_trunc_page(dyld_all_image_infos_address + dyld_slide_amount, vm_map_page_mask(current_map())), kr);
8213 			}
8214 		}
8215 	}
8216 #endif /* FIXED_76621401 */
8217 }
8218 
8219 static int
8220 sysctl_libmalloc_experiments SYSCTL_HANDLER_ARGS
8221 {
8222 #pragma unused(oidp, arg2, req)
8223 	int changed;
8224 	errno_t error;
8225 	uint64_t value = os_atomic_load_wide(&libmalloc_experiment_factors, relaxed);
8226 
8227 	error = sysctl_io_number(req, value, sizeof(value), &value, &changed);
8228 	if (error) {
8229 		return error;
8230 	}
8231 
8232 	if (changed) {
8233 		os_atomic_store_wide(&libmalloc_experiment_factors, value, relaxed);
8234 	}
8235 
8236 	return 0;
8237 }
8238 
8239 EXPERIMENT_FACTOR_PROC(_kern, libmalloc_experiments, CTLTYPE_QUAD | CTLFLAG_RW, 0, 0, &sysctl_libmalloc_experiments, "A", "");
8240 
8241 SYSCTL_NODE(_kern, OID_AUTO, sec_transition,
8242     CTLFLAG_RD | CTLFLAG_LOCKED, 0, "sec_transition");
8243 
8244 #if DEBUG || DEVELOPMENT
8245 static int
sysctl_setup_ensure_pidversion_changes_on_exec(__unused int64_t in,int64_t * out)8246 sysctl_setup_ensure_pidversion_changes_on_exec(__unused int64_t in, int64_t *out)
8247 {
8248 	// Tweak nextpidversion to try to trigger a reuse (unless the exec code is doing the right thing)
8249 	int current_pid_version = proc_get_ro(current_proc())->p_idversion;
8250 	nextpidversion = current_pid_version;
8251 	*out = 0;
8252 	return KERN_SUCCESS;
8253 }
8254 
8255 SYSCTL_TEST_REGISTER(setup_ensure_pidversion_changes_on_exec, sysctl_setup_ensure_pidversion_changes_on_exec);
8256 #endif /* DEBUG || DEVELOPMENT */
8257