xref: /xnu-12377.81.4/tests/arm_mte_unentitled.c (revision 043036a2b3718f7f0be807e2870f8f47d3fa0796)
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28 
29 #if __arm64__
30 #include <arm_acle.h>
31 #include <darwintest.h>
32 #include <fcntl.h>
33 #include <libproc.h>
34 #include <mach/mach.h>
35 #include <mach/mach_vm.h>
36 #include <mach/vm_map.h>
37 #include <signal.h>
38 #include <spawn.h>
39 #include <spawn_private.h>
40 #include <sys/mman.h>
41 
42 #include "arm_mte_utilities.h"
43 #include "test_utils.h"
44 
45 T_DECL(mte_alloc_from_unentitled,
46     "Attempt to allocate tagged memory from MTE-disabled process",
47     T_META_REQUIRES_SYSCTL_EQ("hw.optional.arm.FEAT_MTE2", 1),
48     XNU_T_META_SOC_SPECIFIC)
49 {
50 	vm_address_t address = 0;
51 	vm_size_t alloc_size = 16 * 1024;
52 
53 	kern_return_t kr = vm_allocate(mach_task_self(), &address, alloc_size, VM_FLAGS_ANYWHERE | VM_FLAGS_MTE);
54 	T_EXPECT_MACH_ERROR_(kr, KERN_INVALID_ARGUMENT, "allocate tagged memory in unentitled process");
55 
56 	if (kr == KERN_SUCCESS) {
57 		// cleanup if the test failed
58 		kr = vm_deallocate(mach_task_self(), address, alloc_size);
59 		T_ASSERT_MACH_SUCCESS(kr, "test cleanup");
60 	}
61 }
62 
63 /* Here, "debugger" means an MTE-disabled process with access to tagged memory */
64 T_DECL(mte_debugger_untagged_copyio,
65     "Test that debugger processes can do copyio operations without tag checks",
66     T_META_REQUIRES_SYSCTL_EQ("hw.optional.arm.FEAT_MTE2", 1),
67     XNU_T_META_SOC_SPECIFIC,
68     /* Allow ourselves to act as a debugger */
69     T_META_BOOTARGS_SET("amfi_unrestrict_task_for_pid=1"),
70     T_META_ASROOT(true))
71 {
72 	__block kern_return_t kr;
73 	/* This is the debugger process (MTE disabled) */
74 
75 	T_SETUPBEGIN;
76 	char *shm_name = "mte_debugger_untagged_copyio";
77 	const mach_vm_size_t ALLOC_SIZE = PAGE_SIZE;
78 
79 	/* create shared memory descriptor for sending address */
80 	shm_unlink(shm_name);
81 	int fd = shm_open(shm_name, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
82 	T_ASSERT_POSIX_SUCCESS(fd, "shm_open");
83 
84 	int ret = ftruncate(fd, sizeof(vm_address_t));
85 	T_ASSERT_POSIX_SUCCESS(ret, "ftruncate");
86 
87 	volatile vm_address_t *shm = mmap(NULL, sizeof(vm_address_t), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
88 	T_ASSERT_NE(shm, MAP_FAILED, "mmap");
89 	/* tell the process being "debugged" how much memory to allocate */
90 	*shm = ALLOC_SIZE;
91 	T_SETUPEND;
92 
93 	/* Launch the to-be-debugged process, which has the MTE code-signing entitlement */
94 	char *new_argv[] = { "arm_mte_debugger_helper", shm_name, NULL };
95 	pid_t child_pid;
96 	ret = posix_spawn(&child_pid, new_argv[0], NULL, NULL, new_argv, NULL);
97 	T_ASSERT_POSIX_ZERO(ret, "posix_spawn");
98 	T_ASSERT_NE(child_pid, 0, "posix_spawn child_pid");
99 
100 	/* Wait for the process to send the allocated address over */
101 	while (*shm == ALLOC_SIZE) {
102 		/* check that the process is still alive */
103 		ret = kill(child_pid, 0); // note: signal 0 does not affect the child
104 
105 		/* fails with errno = ESRCH if the child process is dead */
106 		T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "kill");
107 	}
108 
109 	vm_address_t child_addr = *shm;
110 	T_ASSERT_EQ(child_addr & MTE_TAG_MASK, 0ULL, "received untagged pointer");
111 
112 	mach_port_t child_task;
113 	kr = task_for_pid(mach_task_self(), child_pid, &child_task);
114 	T_ASSERT_MACH_SUCCESS(kr, "fetch task_for_pid(child)");
115 
116 	vm_address_t dest_addr = 0;
117 	vm_prot_t cur_prot = VM_PROT_DEFAULT, max_prot = VM_PROT_DEFAULT;
118 	/* remap the process' tagged memory into the debugger's address space */
119 	kr = vm_remap(mach_task_self(), &dest_addr, ALLOC_SIZE,
120 	    /* mask = */ 0, VM_FLAGS_ANYWHERE, child_task, child_addr,
121 	    /* copy = */ false, &cur_prot, &max_prot, VM_INHERIT_DEFAULT);
122 	T_ASSERT_MACH_SUCCESS(kr, "remapped process' tagged memory into debugger");
123 
124 	/* create a source region for copyio */
125 	vm_address_t src_addr = 0;
126 	kr = vm_allocate(mach_task_self(), &src_addr, ALLOC_SIZE, VM_FLAGS_ANYWHERE);
127 	T_ASSERT_MACH_SUCCESS(kr, "vm_allocate source region");
128 	memset((void*) src_addr, 'A', ALLOC_SIZE);
129 
130 	/* make sure the debugger can copyio the tagged memory with its untagged pointer */
131 	expect_normal_exit(^{
132 		kr = mach_vm_copy(mach_task_self(), src_addr, ALLOC_SIZE, dest_addr);
133 		T_EXPECT_MACH_SUCCESS(kr, "copyio using untagged pointer from debugger");
134 	}, "copyio tagged memory from debugger");
135 
136 	/* cleanup */
137 	T_SETUPBEGIN;
138 	ret = close(fd);
139 	T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "close");
140 	ret = shm_unlink(shm_name);
141 	T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "shm_unlink");
142 	kr = mach_vm_deallocate(mach_task_self(), dest_addr, ALLOC_SIZE);
143 	T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "deallocate remapped memory");
144 	kr = mach_vm_deallocate(mach_task_self(), src_addr, ALLOC_SIZE);
145 	T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "deallocate source region");
146 	kr = mach_port_deallocate(mach_task_self(), child_task);
147 	T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "deallocate child task port");
148 	T_SETUPEND;
149 }
150 #endif /* __arm64__ */
151