xref: /xnu-8796.101.5/bsd/sys/cprotect.h (revision aca3beaa3dfbd42498b42c5e5ce20a938e6554e5)
1 /*
2  * Copyright (c) 2009-2022 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 
29 #ifndef _SYS_CPROTECT_H_
30 #define _SYS_CPROTECT_H_
31 
32 #ifdef KERNEL_PRIVATE
33 
34 #include <sys/cdefs.h>
35 #include <sys/param.h>
36 #include <sys/buf.h>
37 #include <sys/kdebug.h>
38 #include <crypto/aes.h>
39 #include <stdbool.h>
40 #include <uuid/uuid.h>
41 #include <libkern/crypto/sha1.h>
42 
43 __BEGIN_DECLS
44 
45 #define CP_CODE(code) FSDBG_CODE(DBG_CONTENT_PROT, code)
46 /*
47  * Class DBG_FSYSTEM == 0x03
48  * Subclass DBG_CONTENT_PROT == 0xCF
49  * These debug codes are of the form 0x03CFzzzz
50  */
51 
52 enum {
53 	CPDBG_OFFSET_IO = CP_CODE(0),   /* 0x03CF0000 */
54 };
55 
56 /* normally the debug events are no-ops */
57 #define CP_DEBUG(x, a, b, c, d, e) do {} while (0);
58 
59 /* dev kernels only! */
60 #if !SECURE_KERNEL
61 
62 /* KDEBUG events used by content protection subsystem */
63 #if 0
64 #undef CP_DEBUG
65 #define CP_DEBUG KERNEL_DEBUG_CONSTANT
66 #endif
67 
68 #endif
69 
70 #define CP_MAX_WRAPPEDKEYSIZE     128   /* The size of the largest allowed key */
71 #define VFS_CP_MAX_CACHEBUFLEN    64    /* Maximum size of the cached key */
72 
73 /* lock events from AppleKeyStore */
74 enum {
75 	CP_ACTION_LOCKED         = 0,
76 	CP_ACTION_UNLOCKED       = 1,
77 	CP_ACTION_EP_INVALIDATED = 2,
78 };
79 /*
80  * Ideally, cp_key_store_action_t would be an enum, but we cannot fix
81  * that until AppleKeyStore is updated.
82  */
83 typedef int cp_key_store_action_t;
84 
85 /*
86  * It was once the case (and it may still be the case) where the lock
87  * state got conflated with the possible actions/events that
88  * AppleKeyStore can send.  For that reason, the locked states below
89  * should numerically match their corresponding actions above.
90  */
91 typedef unsigned char cp_lock_state_t;
92 enum {
93 	CP_LOCKED_STATE         = 0,
94 	CP_UNLOCKED_STATE       = 1,
95 };
96 
97 typedef unsigned char cp_ep_state_t;
98 enum {
99 	CP_EP_INVALIDATED       = 0,
100 };
101 
102 typedef uint32_t cp_key_class_t;
103 typedef uint32_t cp_key_os_version_t;
104 typedef uint16_t cp_key_revision_t;
105 typedef uint64_t cp_crypto_id_t;
106 
107 typedef struct cprotect *cprotect_t;
108 typedef struct cpx *cpx_t;
109 
110 #ifdef BSD_KERNEL_PRIVATE
111 /* Not for consumption outside of XNU */
112 typedef uint32_t cpx_flags_t;
113 /*
114  * This is a CPX structure with a fixed-length key buffer. We need this defined in a header
115  * so that we can use this structure to allocate the memory for the zone(s) properly.
116  */
117 typedef struct fcpx {
118 #ifdef DEBUG
119 	uint32_t                cpx_magic1;
120 #endif // DEBUG
121 	aes_encrypt_ctx         *cpx_iv_aes_ctx_ptr;// Context used for generating the IV
122 	cpx_flags_t             cpx_flags;
123 	uint16_t                cpx_max_key_len;
124 	uint16_t                cpx_key_len;
125 	uint8_t                 cpx_cached_key[VFS_CP_MAX_CACHEBUFLEN];
126 	//Fixed length all the way through
127 } fcpx_t;
128 
129 #endif // BSD_KERNEL_PRIVATE
130 
131 typedef struct cp_key {
132 	uint8_t len;
133 	void *key;
134 } cp_key_t;
135 
136 /* Interface to AKS kext */
137 typedef struct {
138 	void     *key;
139 	unsigned key_len;
140 	void     *iv_key;
141 	unsigned iv_key_len;
142 	uint32_t flags;
143 } cp_raw_key_s;
144 
145 typedef cp_raw_key_s* cp_raw_key_t;
146 
147 typedef struct {
148 	void     *key;
149 	unsigned key_len;
150 	cp_key_class_t dp_class;
151 } cp_wrapped_key_s;
152 
153 typedef cp_wrapped_key_s* cp_wrapped_key_t;
154 
155 typedef struct {
156 	union {
157 		ino64_t                 inode;
158 		cp_crypto_id_t  crypto_id;
159 	};
160 	uint32_t                        volume;
161 	pid_t                           pid;
162 	uid_t                           uid;
163 	cp_key_revision_t       key_revision;
164 } cp_cred_s;
165 
166 typedef cp_cred_s* cp_cred_t;
167 
168 /* The wrappers are invoked on the AKS kext */
169 typedef int unwrapper_t(cp_cred_t access, const cp_wrapped_key_t wrapped_key_in, cp_raw_key_t key_out);
170 typedef int rewrapper_t(cp_cred_t access, cp_key_class_t dp_class, const cp_wrapped_key_t wrapped_key_in, cp_wrapped_key_t wrapped_key_out);
171 typedef int new_key_t(cp_cred_t access, cp_key_class_t dp_class, cp_raw_key_t key_out, cp_wrapped_key_t wrapped_key_out);
172 typedef int invalidater_t(cp_cred_t access); /* invalidates keys */
173 typedef int backup_key_t(cp_cred_t access, const cp_wrapped_key_t wrapped_key_in, cp_wrapped_key_t wrapped_key_out);
174 
175 /*
176  * Flags for Interaction between AKS / Kernel
177  * These are twiddled via the input/output structs in the above
178  * wrapper/unwrapper functions.
179  */
180 #define CP_RAW_KEY_WRAPPEDKEY   0x00000001
181 
182 /*
183  * Function prototypes for kexts to interface with our internal cprotect
184  * fields;  cpx provides opacity and allows us to modify behavior internally
185  * without requiring kext changes.
186  */
187 cpx_t cpx_alloc(size_t key_size, bool needs_ctx);
188 int cpx_alloc_ctx(cpx_t cpx);
189 void cpx_free_ctx(cpx_t cpx);
190 void cpx_init(cpx_t, size_t key_len);
191 void cpx_init_ctx_ptr(cpx_t cpx);
192 void cpx_free(cpx_t);
193 void cpx_writeprotect(cpx_t cpx);
194 __attribute__((const)) size_t cpx_size(size_t key_len);
195 __attribute__((pure)) bool cpx_is_sep_wrapped_key(const struct cpx *);
196 void cpx_set_is_sep_wrapped_key(struct cpx *, bool);
197 __attribute__((pure)) bool cpx_is_composite_key(const struct cpx *);
198 void cpx_set_is_composite_key(struct cpx *, bool);
199 __attribute__((pure)) bool cpx_use_offset_for_iv(const struct cpx *);
200 void cpx_set_use_offset_for_iv(struct cpx *, bool);
201 __attribute__((pure)) bool cpx_synthetic_offset_for_iv(const struct cpx *);
202 void cpx_set_synthetic_offset_for_iv(struct cpx *, bool);
203 __attribute__((pure)) uint16_t cpx_key_len(const struct cpx *);
204 void cpx_set_key_len(struct cpx *, uint16_t key_len);
205 __attribute__((pure)) void *cpx_key(const struct cpx *);
206 aes_encrypt_ctx *cpx_iv_aes_ctx(struct cpx *);
207 void cpx_flush(cpx_t cpx);
208 bool cpx_can_copy(const struct cpx *src, const struct cpx *dst);
209 void cpx_copy(const struct cpx *src, cpx_t dst);
210 uint16_t cpx_max_key_len(const struct cpx *cpx);
211 bool cpx_has_key(const struct cpx *cpx);
212 size_t cpx_sizex(const struct cpx *cpx);
213 void cpx_set_aes_iv_key(struct cpx *cpx, void *iv_key);
214 
215 int cp_key_store_action(cp_key_store_action_t);
216 int cp_key_store_action_for_volume(uuid_t volume_uuid, cp_key_store_action_t action);
217 cp_key_os_version_t cp_os_version(void);
218 // Should be cp_key_class_t but HFS has a conflicting definition
219 int cp_is_valid_class(int isdir, int32_t protectionclass);
220 
221 __END_DECLS
222 
223 #endif /* KERNEL_PRIVATE */
224 #endif /* !_SYS_CPROTECT_H_ */
225