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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
76181c13 | 2 | /* Authentication token and access key management |
1da177e4 | 3 | * |
76181c13 | 4 | * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved. |
1da177e4 LT |
5 | * Written by David Howells (dhowells@redhat.com) |
6 | * | |
b68101a1 | 7 | * See Documentation/security/keys/core.rst for information on keys/keyrings. |
1da177e4 LT |
8 | */ |
9 | ||
10 | #ifndef _LINUX_KEY_H | |
11 | #define _LINUX_KEY_H | |
12 | ||
13 | #include <linux/types.h> | |
14 | #include <linux/list.h> | |
15 | #include <linux/rbtree.h> | |
76d8aeab | 16 | #include <linux/rcupdate.h> |
0b77f5bf | 17 | #include <linux/sysctl.h> |
aa84442d | 18 | #include <linux/rwsem.h> |
60063497 | 19 | #include <linux/atomic.h> |
b2a4df20 | 20 | #include <linux/assoc_array.h> |
fff29291 | 21 | #include <linux/refcount.h> |
074d5898 | 22 | #include <linux/time64.h> |
1da177e4 LT |
23 | |
24 | #ifdef __KERNEL__ | |
9a56c2db | 25 | #include <linux/uidgid.h> |
1da177e4 LT |
26 | |
27 | /* key handle serial number */ | |
28 | typedef int32_t key_serial_t; | |
29 | ||
30 | /* key handle permissions mask */ | |
31 | typedef uint32_t key_perm_t; | |
32 | ||
33 | struct key; | |
34 | ||
35 | #ifdef CONFIG_KEYS | |
36 | ||
37 | #undef KEY_DEBUGGING | |
38 | ||
664cceb0 DH |
39 | #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */ |
40 | #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */ | |
41 | #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */ | |
42 | #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */ | |
43 | #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */ | |
29db9190 DH |
44 | #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */ |
45 | #define KEY_POS_ALL 0x3f000000 | |
664cceb0 DH |
46 | |
47 | #define KEY_USR_VIEW 0x00010000 /* user permissions... */ | |
48 | #define KEY_USR_READ 0x00020000 | |
49 | #define KEY_USR_WRITE 0x00040000 | |
50 | #define KEY_USR_SEARCH 0x00080000 | |
51 | #define KEY_USR_LINK 0x00100000 | |
29db9190 DH |
52 | #define KEY_USR_SETATTR 0x00200000 |
53 | #define KEY_USR_ALL 0x003f0000 | |
1da177e4 LT |
54 | |
55 | #define KEY_GRP_VIEW 0x00000100 /* group permissions... */ | |
56 | #define KEY_GRP_READ 0x00000200 | |
57 | #define KEY_GRP_WRITE 0x00000400 | |
58 | #define KEY_GRP_SEARCH 0x00000800 | |
59 | #define KEY_GRP_LINK 0x00001000 | |
29db9190 DH |
60 | #define KEY_GRP_SETATTR 0x00002000 |
61 | #define KEY_GRP_ALL 0x00003f00 | |
1da177e4 LT |
62 | |
63 | #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */ | |
64 | #define KEY_OTH_READ 0x00000002 | |
65 | #define KEY_OTH_WRITE 0x00000004 | |
66 | #define KEY_OTH_SEARCH 0x00000008 | |
67 | #define KEY_OTH_LINK 0x00000010 | |
29db9190 DH |
68 | #define KEY_OTH_SETATTR 0x00000020 |
69 | #define KEY_OTH_ALL 0x0000003f | |
1da177e4 | 70 | |
6b79ccb5 AR |
71 | #define KEY_PERM_UNDEF 0xffffffff |
72 | ||
1da177e4 LT |
73 | struct seq_file; |
74 | struct user_struct; | |
75 | struct signal_struct; | |
d84f4f99 | 76 | struct cred; |
1da177e4 LT |
77 | |
78 | struct key_type; | |
79 | struct key_owner; | |
80 | struct keyring_list; | |
81 | struct keyring_name; | |
82 | ||
16feef43 DH |
83 | struct keyring_index_key { |
84 | struct key_type *type; | |
85 | const char *description; | |
86 | size_t desc_len; | |
87 | }; | |
88 | ||
146aa8b1 DH |
89 | union key_payload { |
90 | void __rcu *rcu_data0; | |
91 | void *data[4]; | |
92 | }; | |
93 | ||
664cceb0 DH |
94 | /*****************************************************************************/ |
95 | /* | |
96 | * key reference with possession attribute handling | |
97 | * | |
98 | * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually | |
99 | * defined. This is because we abuse the bottom bit of the reference to carry a | |
100 | * flag to indicate whether the calling process possesses that key in one of | |
101 | * its keyrings. | |
102 | * | |
103 | * the key_ref_t has been made a separate type so that the compiler can reject | |
104 | * attempts to dereference it without proper conversion. | |
105 | * | |
106 | * the three functions are used to assemble and disassemble references | |
107 | */ | |
108 | typedef struct __key_reference_with_attributes *key_ref_t; | |
109 | ||
110 | static inline key_ref_t make_key_ref(const struct key *key, | |
a5b4bd28 | 111 | bool possession) |
664cceb0 DH |
112 | { |
113 | return (key_ref_t) ((unsigned long) key | possession); | |
114 | } | |
115 | ||
116 | static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) | |
117 | { | |
118 | return (struct key *) ((unsigned long) key_ref & ~1UL); | |
119 | } | |
120 | ||
a5b4bd28 | 121 | static inline bool is_key_possessed(const key_ref_t key_ref) |
664cceb0 DH |
122 | { |
123 | return (unsigned long) key_ref & 1UL; | |
124 | } | |
125 | ||
aaf66c88 | 126 | typedef int (*key_restrict_link_func_t)(struct key *dest_keyring, |
469ff8f7 | 127 | const struct key_type *type, |
aaf66c88 MM |
128 | const union key_payload *payload, |
129 | struct key *restriction_key); | |
469ff8f7 | 130 | |
e9cc0f68 MM |
131 | struct key_restriction { |
132 | key_restrict_link_func_t check; | |
133 | struct key *key; | |
134 | struct key_type *keytype; | |
135 | }; | |
136 | ||
363b02da DH |
137 | enum key_state { |
138 | KEY_IS_UNINSTANTIATED, | |
139 | KEY_IS_POSITIVE, /* Positively instantiated */ | |
140 | }; | |
141 | ||
1da177e4 LT |
142 | /*****************************************************************************/ |
143 | /* | |
144 | * authentication token / access credential / keyring | |
145 | * - types of key include: | |
146 | * - keyrings | |
147 | * - disk encryption IDs | |
148 | * - Kerberos TGTs and tickets | |
149 | */ | |
150 | struct key { | |
fff29291 | 151 | refcount_t usage; /* number of references */ |
1da177e4 | 152 | key_serial_t serial; /* key serial number */ |
65d87fe6 DH |
153 | union { |
154 | struct list_head graveyard_link; | |
155 | struct rb_node serial_node; | |
156 | }; | |
1da177e4 LT |
157 | struct rw_semaphore sem; /* change vs change sem */ |
158 | struct key_user *user; /* owner of this key */ | |
29db9190 | 159 | void *security; /* security data for this key */ |
5d135440 | 160 | union { |
074d5898 BW |
161 | time64_t expiry; /* time at which key expires (or 0) */ |
162 | time64_t revoked_at; /* time at which key was revoked */ | |
5d135440 | 163 | }; |
074d5898 | 164 | time64_t last_used_at; /* last time used for LRU keyring discard */ |
9a56c2db EB |
165 | kuid_t uid; |
166 | kgid_t gid; | |
1da177e4 LT |
167 | key_perm_t perm; /* access permissions */ |
168 | unsigned short quotalen; /* length added to quota */ | |
76d8aeab DH |
169 | unsigned short datalen; /* payload data length |
170 | * - may not match RCU dereferenced payload | |
171 | * - payload should contain own length | |
172 | */ | |
363b02da | 173 | short state; /* Key state (+) or rejection error (-) */ |
1da177e4 LT |
174 | |
175 | #ifdef KEY_DEBUGGING | |
176 | unsigned magic; | |
177 | #define KEY_DEBUG_MAGIC 0x18273645u | |
1da177e4 LT |
178 | #endif |
179 | ||
76d8aeab | 180 | unsigned long flags; /* status flags (change with bitops) */ |
363b02da DH |
181 | #define KEY_FLAG_DEAD 0 /* set if key type has been deleted */ |
182 | #define KEY_FLAG_REVOKED 1 /* set if key had been revoked */ | |
183 | #define KEY_FLAG_IN_QUOTA 2 /* set if key consumes quota */ | |
184 | #define KEY_FLAG_USER_CONSTRUCT 3 /* set if key is being constructed in userspace */ | |
185 | #define KEY_FLAG_ROOT_CAN_CLEAR 4 /* set if key can be cleared by root without permission */ | |
186 | #define KEY_FLAG_INVALIDATED 5 /* set if key has been invalidated */ | |
187 | #define KEY_FLAG_BUILTIN 6 /* set if key is built in to the kernel */ | |
188 | #define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */ | |
189 | #define KEY_FLAG_KEEP 8 /* set if key should not be removed */ | |
190 | #define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */ | |
76d8aeab | 191 | |
16feef43 DH |
192 | /* the key type and key description string |
193 | * - the desc is used to match a key against search criteria | |
194 | * - it should be a printable string | |
1da177e4 LT |
195 | * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" |
196 | */ | |
16feef43 DH |
197 | union { |
198 | struct keyring_index_key index_key; | |
199 | struct { | |
200 | struct key_type *type; /* type of key */ | |
201 | char *description; | |
202 | }; | |
203 | }; | |
1da177e4 | 204 | |
1da177e4 LT |
205 | /* key data |
206 | * - this is used to hold the data actually used in cryptography or | |
207 | * whatever | |
208 | */ | |
209 | union { | |
146aa8b1 DH |
210 | union key_payload payload; |
211 | struct { | |
212 | /* Keyring bits */ | |
213 | struct list_head name_link; | |
214 | struct assoc_array keys; | |
215 | }; | |
b2a4df20 | 216 | }; |
5ac7eace DH |
217 | |
218 | /* This is set on a keyring to restrict the addition of a link to a key | |
2b6aa412 | 219 | * to it. If this structure isn't provided then it is assumed that the |
5ac7eace | 220 | * keyring is open to any addition. It is ignored for non-keyring |
6563c91f MM |
221 | * keys. Only set this value using keyring_restrict(), keyring_alloc(), |
222 | * or key_alloc(). | |
5ac7eace DH |
223 | * |
224 | * This is intended for use with rings of trusted keys whereby addition | |
225 | * to the keyring needs to be controlled. KEY_ALLOC_BYPASS_RESTRICTION | |
226 | * overrides this, allowing the kernel to add extra keys without | |
227 | * restriction. | |
228 | */ | |
2b6aa412 | 229 | struct key_restriction *restrict_link; |
1da177e4 LT |
230 | }; |
231 | ||
1da177e4 LT |
232 | extern struct key *key_alloc(struct key_type *type, |
233 | const char *desc, | |
9a56c2db | 234 | kuid_t uid, kgid_t gid, |
d84f4f99 | 235 | const struct cred *cred, |
7e047ef5 | 236 | key_perm_t perm, |
5ac7eace | 237 | unsigned long flags, |
2b6aa412 | 238 | struct key_restriction *restrict_link); |
7e047ef5 DH |
239 | |
240 | ||
5ac7eace DH |
241 | #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ |
242 | #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ | |
243 | #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ | |
77f68bac DH |
244 | #define KEY_ALLOC_BUILT_IN 0x0004 /* Key is built into kernel */ |
245 | #define KEY_ALLOC_BYPASS_RESTRICTION 0x0008 /* Override the check on restricted keyrings */ | |
237bbd29 | 246 | #define KEY_ALLOC_UID_KEYRING 0x0010 /* allocating a user or user session keyring */ |
7e047ef5 | 247 | |
1da177e4 | 248 | extern void key_revoke(struct key *key); |
fd75815f | 249 | extern void key_invalidate(struct key *key); |
1da177e4 LT |
250 | extern void key_put(struct key *key); |
251 | ||
ccc3e6d9 | 252 | static inline struct key *__key_get(struct key *key) |
1da177e4 | 253 | { |
fff29291 | 254 | refcount_inc(&key->usage); |
1da177e4 LT |
255 | return key; |
256 | } | |
257 | ||
ccc3e6d9 DH |
258 | static inline struct key *key_get(struct key *key) |
259 | { | |
260 | return key ? __key_get(key) : key; | |
261 | } | |
262 | ||
664cceb0 DH |
263 | static inline void key_ref_put(key_ref_t key_ref) |
264 | { | |
265 | key_put(key_ref_to_ptr(key_ref)); | |
266 | } | |
267 | ||
1da177e4 LT |
268 | extern struct key *request_key(struct key_type *type, |
269 | const char *description, | |
270 | const char *callout_info); | |
271 | ||
4e54f085 DH |
272 | extern struct key *request_key_with_auxdata(struct key_type *type, |
273 | const char *description, | |
4a38e122 DH |
274 | const void *callout_info, |
275 | size_t callout_len, | |
4e54f085 DH |
276 | void *aux); |
277 | ||
76181c13 DH |
278 | extern struct key *request_key_async(struct key_type *type, |
279 | const char *description, | |
4a38e122 DH |
280 | const void *callout_info, |
281 | size_t callout_len); | |
76181c13 DH |
282 | |
283 | extern struct key *request_key_async_with_auxdata(struct key_type *type, | |
284 | const char *description, | |
4a38e122 DH |
285 | const void *callout_info, |
286 | size_t callout_len, | |
76181c13 DH |
287 | void *aux); |
288 | ||
289 | extern int wait_for_key_construction(struct key *key, bool intr); | |
290 | ||
b404aef7 | 291 | extern int key_validate(const struct key *key); |
1da177e4 | 292 | |
664cceb0 DH |
293 | extern key_ref_t key_create_or_update(key_ref_t keyring, |
294 | const char *type, | |
295 | const char *description, | |
296 | const void *payload, | |
297 | size_t plen, | |
6b79ccb5 | 298 | key_perm_t perm, |
7e047ef5 | 299 | unsigned long flags); |
1da177e4 | 300 | |
664cceb0 | 301 | extern int key_update(key_ref_t key, |
1da177e4 LT |
302 | const void *payload, |
303 | size_t plen); | |
304 | ||
305 | extern int key_link(struct key *keyring, | |
306 | struct key *key); | |
307 | ||
308 | extern int key_unlink(struct key *keyring, | |
309 | struct key *key); | |
310 | ||
9a56c2db | 311 | extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
d84f4f99 | 312 | const struct cred *cred, |
96b5c8fe | 313 | key_perm_t perm, |
7e047ef5 | 314 | unsigned long flags, |
2b6aa412 | 315 | struct key_restriction *restrict_link, |
d720024e | 316 | struct key *dest); |
1da177e4 | 317 | |
5ac7eace DH |
318 | extern int restrict_link_reject(struct key *keyring, |
319 | const struct key_type *type, | |
aaf66c88 MM |
320 | const union key_payload *payload, |
321 | struct key *restriction_key); | |
5ac7eace | 322 | |
1da177e4 LT |
323 | extern int keyring_clear(struct key *keyring); |
324 | ||
664cceb0 DH |
325 | extern key_ref_t keyring_search(key_ref_t keyring, |
326 | struct key_type *type, | |
327 | const char *description); | |
1da177e4 | 328 | |
1da177e4 LT |
329 | extern int keyring_add_key(struct key *keyring, |
330 | struct key *key); | |
331 | ||
6563c91f MM |
332 | extern int keyring_restrict(key_ref_t keyring, const char *type, |
333 | const char *restriction); | |
334 | ||
1da177e4 LT |
335 | extern struct key *key_lookup(key_serial_t id); |
336 | ||
456a8167 | 337 | static inline key_serial_t key_serial(const struct key *key) |
7249db2c DH |
338 | { |
339 | return key ? key->serial : 0; | |
340 | } | |
1da177e4 | 341 | |
59e6b9c1 BS |
342 | extern void key_set_timeout(struct key *, unsigned); |
343 | ||
76ef5e17 DJ |
344 | extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags, |
345 | key_perm_t perm); | |
346 | ||
f5895943 DH |
347 | /* |
348 | * The permissions required on a key that we're looking up. | |
349 | */ | |
350 | #define KEY_NEED_VIEW 0x01 /* Require permission to view attributes */ | |
351 | #define KEY_NEED_READ 0x02 /* Require permission to read content */ | |
352 | #define KEY_NEED_WRITE 0x04 /* Require permission to update / modify */ | |
353 | #define KEY_NEED_SEARCH 0x08 /* Require permission to search (keyring) or find (key) */ | |
354 | #define KEY_NEED_LINK 0x10 /* Require permission to link */ | |
355 | #define KEY_NEED_SETATTR 0x20 /* Require permission to change attributes */ | |
356 | #define KEY_NEED_ALL 0x3f /* All the above permissions */ | |
357 | ||
363b02da DH |
358 | static inline short key_read_state(const struct key *key) |
359 | { | |
360 | /* Barrier versus mark_key_instantiated(). */ | |
361 | return smp_load_acquire(&key->state); | |
362 | } | |
363 | ||
78b7280c | 364 | /** |
363b02da | 365 | * key_is_positive - Determine if a key has been positively instantiated |
78b7280c DH |
366 | * @key: The key to check. |
367 | * | |
368 | * Return true if the specified key has been positively instantiated, false | |
369 | * otherwise. | |
370 | */ | |
363b02da DH |
371 | static inline bool key_is_positive(const struct key *key) |
372 | { | |
373 | return key_read_state(key) == KEY_IS_POSITIVE; | |
374 | } | |
375 | ||
376 | static inline bool key_is_negative(const struct key *key) | |
78b7280c | 377 | { |
363b02da | 378 | return key_read_state(key) < 0; |
78b7280c DH |
379 | } |
380 | ||
0837e49a DH |
381 | #define dereference_key_rcu(KEY) \ |
382 | (rcu_dereference((KEY)->payload.rcu_data0)) | |
383 | ||
384 | #define dereference_key_locked(KEY) \ | |
146aa8b1 | 385 | (rcu_dereference_protected((KEY)->payload.rcu_data0, \ |
633e804e DH |
386 | rwsem_is_locked(&((struct key *)(KEY))->sem))) |
387 | ||
ee0b31a2 | 388 | #define rcu_assign_keypointer(KEY, PAYLOAD) \ |
e5c1f444 | 389 | do { \ |
146aa8b1 | 390 | rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \ |
e5c1f444 | 391 | } while (0) |
ee0b31a2 | 392 | |
0b77f5bf | 393 | #ifdef CONFIG_SYSCTL |
d6f50c95 | 394 | extern struct ctl_table key_sysctls[]; |
0b77f5bf | 395 | #endif |
1da177e4 LT |
396 | /* |
397 | * the userspace interface | |
398 | */ | |
d84f4f99 | 399 | extern int install_thread_keyring_to_cred(struct cred *cred); |
1da177e4 LT |
400 | extern void key_fsuid_changed(struct task_struct *tsk); |
401 | extern void key_fsgid_changed(struct task_struct *tsk); | |
402 | extern void key_init(void); | |
403 | ||
404 | #else /* CONFIG_KEYS */ | |
405 | ||
406 | #define key_validate(k) 0 | |
407 | #define key_serial(k) 0 | |
7888e7ff | 408 | #define key_get(k) ({ NULL; }) |
0dab9cfa | 409 | #define key_revoke(k) do { } while(0) |
fd75815f | 410 | #define key_invalidate(k) do { } while(0) |
1da177e4 | 411 | #define key_put(k) do { } while(0) |
664cceb0 | 412 | #define key_ref_put(k) do { } while(0) |
8bbf4976 DH |
413 | #define make_key_ref(k, p) NULL |
414 | #define key_ref_to_ptr(k) NULL | |
664cceb0 | 415 | #define is_key_possessed(k) 0 |
1da177e4 LT |
416 | #define key_fsuid_changed(t) do { } while(0) |
417 | #define key_fsgid_changed(t) do { } while(0) | |
418 | #define key_init() do { } while(0) | |
419 | ||
420 | #endif /* CONFIG_KEYS */ | |
421 | #endif /* __KERNEL__ */ | |
422 | #endif /* _LINUX_KEY_H */ |