1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
2 | /* Authentication token and access key management |
3 | * |
4 | * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved. |
5 | * Written by David Howells (dhowells@redhat.com) |
6 | * |
7 | * See Documentation/security/keys/core.rst for information on keys/keyrings. |
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> |
16 | #include <linux/rcupdate.h> |
17 | #include <linux/sysctl.h> |
18 | #include <linux/rwsem.h> |
19 | #include <linux/atomic.h> |
20 | #include <linux/assoc_array.h> |
21 | #include <linux/refcount.h> |
22 | #include <linux/time64.h> |
23 | |
24 | #ifdef __KERNEL__ |
25 | #include <linux/uidgid.h> |
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 | struct net; |
35 | |
36 | #ifdef CONFIG_KEYS |
37 | |
38 | #undef KEY_DEBUGGING |
39 | |
40 | #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */ |
41 | #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */ |
42 | #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */ |
43 | #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */ |
44 | #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */ |
45 | #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */ |
46 | #define KEY_POS_ALL 0x3f000000 |
47 | |
48 | #define KEY_USR_VIEW 0x00010000 /* user permissions... */ |
49 | #define KEY_USR_READ 0x00020000 |
50 | #define KEY_USR_WRITE 0x00040000 |
51 | #define KEY_USR_SEARCH 0x00080000 |
52 | #define KEY_USR_LINK 0x00100000 |
53 | #define KEY_USR_SETATTR 0x00200000 |
54 | #define KEY_USR_ALL 0x003f0000 |
55 | |
56 | #define KEY_GRP_VIEW 0x00000100 /* group permissions... */ |
57 | #define KEY_GRP_READ 0x00000200 |
58 | #define KEY_GRP_WRITE 0x00000400 |
59 | #define KEY_GRP_SEARCH 0x00000800 |
60 | #define KEY_GRP_LINK 0x00001000 |
61 | #define KEY_GRP_SETATTR 0x00002000 |
62 | #define KEY_GRP_ALL 0x00003f00 |
63 | |
64 | #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */ |
65 | #define KEY_OTH_READ 0x00000002 |
66 | #define KEY_OTH_WRITE 0x00000004 |
67 | #define KEY_OTH_SEARCH 0x00000008 |
68 | #define KEY_OTH_LINK 0x00000010 |
69 | #define KEY_OTH_SETATTR 0x00000020 |
70 | #define KEY_OTH_ALL 0x0000003f |
71 | |
72 | #define KEY_PERM_UNDEF 0xffffffff |
73 | |
74 | /* |
75 | * The permissions required on a key that we're looking up. |
76 | */ |
77 | enum key_need_perm { |
78 | KEY_NEED_UNSPECIFIED, /* Needed permission unspecified */ |
79 | KEY_NEED_VIEW, /* Require permission to view attributes */ |
80 | KEY_NEED_READ, /* Require permission to read content */ |
81 | KEY_NEED_WRITE, /* Require permission to update / modify */ |
82 | KEY_NEED_SEARCH, /* Require permission to search (keyring) or find (key) */ |
83 | KEY_NEED_LINK, /* Require permission to link */ |
84 | KEY_NEED_SETATTR, /* Require permission to change attributes */ |
85 | KEY_NEED_UNLINK, /* Require permission to unlink key */ |
86 | KEY_SYSADMIN_OVERRIDE, /* Special: override by CAP_SYS_ADMIN */ |
87 | KEY_AUTHTOKEN_OVERRIDE, /* Special: override by possession of auth token */ |
88 | KEY_DEFER_PERM_CHECK, /* Special: permission check is deferred */ |
89 | }; |
90 | |
91 | enum key_lookup_flag { |
92 | KEY_LOOKUP_CREATE = 0x01, |
93 | KEY_LOOKUP_PARTIAL = 0x02, |
94 | KEY_LOOKUP_ALL = (KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL), |
95 | }; |
96 | |
97 | struct seq_file; |
98 | struct user_struct; |
99 | struct signal_struct; |
100 | struct cred; |
101 | |
102 | struct key_type; |
103 | struct key_owner; |
104 | struct key_tag; |
105 | struct keyring_list; |
106 | struct keyring_name; |
107 | |
108 | struct key_tag { |
109 | struct rcu_head rcu; |
110 | refcount_t usage; |
111 | bool removed; /* T when subject removed */ |
112 | }; |
113 | |
114 | struct keyring_index_key { |
115 | /* [!] If this structure is altered, the union in struct key must change too! */ |
116 | unsigned long hash; /* Hash value */ |
117 | union { |
118 | struct { |
119 | #ifdef __LITTLE_ENDIAN /* Put desc_len at the LSB of x */ |
120 | u16 desc_len; |
121 | char desc[sizeof(long) - 2]; /* First few chars of description */ |
122 | #else |
123 | char desc[sizeof(long) - 2]; /* First few chars of description */ |
124 | u16 desc_len; |
125 | #endif |
126 | }; |
127 | unsigned long x; |
128 | }; |
129 | struct key_type *type; |
130 | struct key_tag *domain_tag; /* Domain of operation */ |
131 | const char *description; |
132 | }; |
133 | |
134 | union key_payload { |
135 | void __rcu *rcu_data0; |
136 | void *data[4]; |
137 | }; |
138 | |
139 | /*****************************************************************************/ |
140 | /* |
141 | * key reference with possession attribute handling |
142 | * |
143 | * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually |
144 | * defined. This is because we abuse the bottom bit of the reference to carry a |
145 | * flag to indicate whether the calling process possesses that key in one of |
146 | * its keyrings. |
147 | * |
148 | * the key_ref_t has been made a separate type so that the compiler can reject |
149 | * attempts to dereference it without proper conversion. |
150 | * |
151 | * the three functions are used to assemble and disassemble references |
152 | */ |
153 | typedef struct __key_reference_with_attributes *key_ref_t; |
154 | |
155 | static inline key_ref_t make_key_ref(const struct key *key, |
156 | bool possession) |
157 | { |
158 | return (key_ref_t) ((unsigned long) key | possession); |
159 | } |
160 | |
161 | static inline struct key *key_ref_to_ptr(const key_ref_t key_ref) |
162 | { |
163 | return (struct key *) ((unsigned long) key_ref & ~1UL); |
164 | } |
165 | |
166 | static inline bool is_key_possessed(const key_ref_t key_ref) |
167 | { |
168 | return (unsigned long) key_ref & 1UL; |
169 | } |
170 | |
171 | typedef int (*key_restrict_link_func_t)(struct key *dest_keyring, |
172 | const struct key_type *type, |
173 | const union key_payload *payload, |
174 | struct key *restriction_key); |
175 | |
176 | struct key_restriction { |
177 | key_restrict_link_func_t check; |
178 | struct key *key; |
179 | struct key_type *keytype; |
180 | }; |
181 | |
182 | enum key_state { |
183 | KEY_IS_UNINSTANTIATED, |
184 | KEY_IS_POSITIVE, /* Positively instantiated */ |
185 | }; |
186 | |
187 | /*****************************************************************************/ |
188 | /* |
189 | * authentication token / access credential / keyring |
190 | * - types of key include: |
191 | * - keyrings |
192 | * - disk encryption IDs |
193 | * - Kerberos TGTs and tickets |
194 | */ |
195 | struct key { |
196 | refcount_t usage; /* number of references */ |
197 | key_serial_t serial; /* key serial number */ |
198 | union { |
199 | struct list_head graveyard_link; |
200 | struct rb_node serial_node; |
201 | }; |
202 | #ifdef CONFIG_KEY_NOTIFICATIONS |
203 | struct watch_list *watchers; /* Entities watching this key for changes */ |
204 | #endif |
205 | struct rw_semaphore sem; /* change vs change sem */ |
206 | struct key_user *user; /* owner of this key */ |
207 | void *security; /* security data for this key */ |
208 | union { |
209 | time64_t expiry; /* time at which key expires (or 0) */ |
210 | time64_t revoked_at; /* time at which key was revoked */ |
211 | }; |
212 | time64_t last_used_at; /* last time used for LRU keyring discard */ |
213 | kuid_t uid; |
214 | kgid_t gid; |
215 | key_perm_t perm; /* access permissions */ |
216 | unsigned short quotalen; /* length added to quota */ |
217 | unsigned short datalen; /* payload data length |
218 | * - may not match RCU dereferenced payload |
219 | * - payload should contain own length |
220 | */ |
221 | short state; /* Key state (+) or rejection error (-) */ |
222 | |
223 | #ifdef KEY_DEBUGGING |
224 | unsigned magic; |
225 | #define KEY_DEBUG_MAGIC 0x18273645u |
226 | #endif |
227 | |
228 | unsigned long flags; /* status flags (change with bitops) */ |
229 | #define KEY_FLAG_DEAD 0 /* set if key type has been deleted */ |
230 | #define KEY_FLAG_REVOKED 1 /* set if key had been revoked */ |
231 | #define KEY_FLAG_IN_QUOTA 2 /* set if key consumes quota */ |
232 | #define KEY_FLAG_USER_CONSTRUCT 3 /* set if key is being constructed in userspace */ |
233 | #define KEY_FLAG_ROOT_CAN_CLEAR 4 /* set if key can be cleared by root without permission */ |
234 | #define KEY_FLAG_INVALIDATED 5 /* set if key has been invalidated */ |
235 | #define KEY_FLAG_BUILTIN 6 /* set if key is built in to the kernel */ |
236 | #define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */ |
237 | #define KEY_FLAG_KEEP 8 /* set if key should not be removed */ |
238 | #define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */ |
239 | |
240 | /* the key type and key description string |
241 | * - the desc is used to match a key against search criteria |
242 | * - it should be a printable string |
243 | * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" |
244 | */ |
245 | union { |
246 | struct keyring_index_key index_key; |
247 | struct { |
248 | unsigned long hash; |
249 | unsigned long len_desc; |
250 | struct key_type *type; /* type of key */ |
251 | struct key_tag *domain_tag; /* Domain of operation */ |
252 | char *description; |
253 | }; |
254 | }; |
255 | |
256 | /* key data |
257 | * - this is used to hold the data actually used in cryptography or |
258 | * whatever |
259 | */ |
260 | union { |
261 | union key_payload payload; |
262 | struct { |
263 | /* Keyring bits */ |
264 | struct list_head name_link; |
265 | struct assoc_array keys; |
266 | }; |
267 | }; |
268 | |
269 | /* This is set on a keyring to restrict the addition of a link to a key |
270 | * to it. If this structure isn't provided then it is assumed that the |
271 | * keyring is open to any addition. It is ignored for non-keyring |
272 | * keys. Only set this value using keyring_restrict(), keyring_alloc(), |
273 | * or key_alloc(). |
274 | * |
275 | * This is intended for use with rings of trusted keys whereby addition |
276 | * to the keyring needs to be controlled. KEY_ALLOC_BYPASS_RESTRICTION |
277 | * overrides this, allowing the kernel to add extra keys without |
278 | * restriction. |
279 | */ |
280 | struct key_restriction *restrict_link; |
281 | }; |
282 | |
283 | extern struct key *key_alloc(struct key_type *type, |
284 | const char *desc, |
285 | kuid_t uid, kgid_t gid, |
286 | const struct cred *cred, |
287 | key_perm_t perm, |
288 | unsigned long flags, |
289 | struct key_restriction *restrict_link); |
290 | |
291 | |
292 | #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */ |
293 | #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */ |
294 | #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */ |
295 | #define KEY_ALLOC_BUILT_IN 0x0004 /* Key is built into kernel */ |
296 | #define KEY_ALLOC_BYPASS_RESTRICTION 0x0008 /* Override the check on restricted keyrings */ |
297 | #define KEY_ALLOC_UID_KEYRING 0x0010 /* allocating a user or user session keyring */ |
298 | #define KEY_ALLOC_SET_KEEP 0x0020 /* Set the KEEP flag on the key/keyring */ |
299 | |
300 | extern void key_revoke(struct key *key); |
301 | extern void key_invalidate(struct key *key); |
302 | extern void key_put(struct key *key); |
303 | extern bool key_put_tag(struct key_tag *tag); |
304 | extern void key_remove_domain(struct key_tag *domain_tag); |
305 | |
306 | static inline struct key *__key_get(struct key *key) |
307 | { |
308 | refcount_inc(r: &key->usage); |
309 | return key; |
310 | } |
311 | |
312 | static inline struct key *key_get(struct key *key) |
313 | { |
314 | return key ? __key_get(key) : key; |
315 | } |
316 | |
317 | static inline void key_ref_put(key_ref_t key_ref) |
318 | { |
319 | key_put(key: key_ref_to_ptr(key_ref)); |
320 | } |
321 | |
322 | extern struct key *request_key_tag(struct key_type *type, |
323 | const char *description, |
324 | struct key_tag *domain_tag, |
325 | const char *callout_info); |
326 | |
327 | extern struct key *request_key_rcu(struct key_type *type, |
328 | const char *description, |
329 | struct key_tag *domain_tag); |
330 | |
331 | extern struct key *request_key_with_auxdata(struct key_type *type, |
332 | const char *description, |
333 | struct key_tag *domain_tag, |
334 | const void *callout_info, |
335 | size_t callout_len, |
336 | void *aux); |
337 | |
338 | /** |
339 | * request_key - Request a key and wait for construction |
340 | * @type: Type of key. |
341 | * @description: The searchable description of the key. |
342 | * @callout_info: The data to pass to the instantiation upcall (or NULL). |
343 | * |
344 | * As for request_key_tag(), but with the default global domain tag. |
345 | */ |
346 | static inline struct key *request_key(struct key_type *type, |
347 | const char *description, |
348 | const char *callout_info) |
349 | { |
350 | return request_key_tag(type, description, NULL, callout_info); |
351 | } |
352 | |
353 | #ifdef CONFIG_NET |
354 | /** |
355 | * request_key_net - Request a key for a net namespace and wait for construction |
356 | * @type: Type of key. |
357 | * @description: The searchable description of the key. |
358 | * @net: The network namespace that is the key's domain of operation. |
359 | * @callout_info: The data to pass to the instantiation upcall (or NULL). |
360 | * |
361 | * As for request_key() except that it does not add the returned key to a |
362 | * keyring if found, new keys are always allocated in the user's quota, the |
363 | * callout_info must be a NUL-terminated string and no auxiliary data can be |
364 | * passed. Only keys that operate the specified network namespace are used. |
365 | * |
366 | * Furthermore, it then works as wait_for_key_construction() to wait for the |
367 | * completion of keys undergoing construction with a non-interruptible wait. |
368 | */ |
369 | #define request_key_net(type, description, net, callout_info) \ |
370 | request_key_tag(type, description, net->key_domain, callout_info) |
371 | |
372 | /** |
373 | * request_key_net_rcu - Request a key for a net namespace under RCU conditions |
374 | * @type: Type of key. |
375 | * @description: The searchable description of the key. |
376 | * @net: The network namespace that is the key's domain of operation. |
377 | * |
378 | * As for request_key_rcu() except that only keys that operate the specified |
379 | * network namespace are used. |
380 | */ |
381 | #define request_key_net_rcu(type, description, net) \ |
382 | request_key_rcu(type, description, net->key_domain) |
383 | #endif /* CONFIG_NET */ |
384 | |
385 | extern int wait_for_key_construction(struct key *key, bool intr); |
386 | |
387 | extern int key_validate(const struct key *key); |
388 | |
389 | extern key_ref_t key_create(key_ref_t keyring, |
390 | const char *type, |
391 | const char *description, |
392 | const void *payload, |
393 | size_t plen, |
394 | key_perm_t perm, |
395 | unsigned long flags); |
396 | |
397 | extern key_ref_t key_create_or_update(key_ref_t keyring, |
398 | const char *type, |
399 | const char *description, |
400 | const void *payload, |
401 | size_t plen, |
402 | key_perm_t perm, |
403 | unsigned long flags); |
404 | |
405 | extern int key_update(key_ref_t key, |
406 | const void *payload, |
407 | size_t plen); |
408 | |
409 | extern int key_link(struct key *keyring, |
410 | struct key *key); |
411 | |
412 | extern int key_move(struct key *key, |
413 | struct key *from_keyring, |
414 | struct key *to_keyring, |
415 | unsigned int flags); |
416 | |
417 | extern int key_unlink(struct key *keyring, |
418 | struct key *key); |
419 | |
420 | extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
421 | const struct cred *cred, |
422 | key_perm_t perm, |
423 | unsigned long flags, |
424 | struct key_restriction *restrict_link, |
425 | struct key *dest); |
426 | |
427 | extern int restrict_link_reject(struct key *keyring, |
428 | const struct key_type *type, |
429 | const union key_payload *payload, |
430 | struct key *restriction_key); |
431 | |
432 | extern int keyring_clear(struct key *keyring); |
433 | |
434 | extern key_ref_t keyring_search(key_ref_t keyring, |
435 | struct key_type *type, |
436 | const char *description, |
437 | bool recurse); |
438 | |
439 | extern int keyring_add_key(struct key *keyring, |
440 | struct key *key); |
441 | |
442 | extern int keyring_restrict(key_ref_t keyring, const char *type, |
443 | const char *restriction); |
444 | |
445 | extern struct key *key_lookup(key_serial_t id); |
446 | |
447 | static inline key_serial_t key_serial(const struct key *key) |
448 | { |
449 | return key ? key->serial : 0; |
450 | } |
451 | |
452 | extern void key_set_timeout(struct key *, unsigned); |
453 | |
454 | extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags, |
455 | enum key_need_perm need_perm); |
456 | extern void key_free_user_ns(struct user_namespace *); |
457 | |
458 | static inline short key_read_state(const struct key *key) |
459 | { |
460 | /* Barrier versus mark_key_instantiated(). */ |
461 | return smp_load_acquire(&key->state); |
462 | } |
463 | |
464 | /** |
465 | * key_is_positive - Determine if a key has been positively instantiated |
466 | * @key: The key to check. |
467 | * |
468 | * Return true if the specified key has been positively instantiated, false |
469 | * otherwise. |
470 | */ |
471 | static inline bool key_is_positive(const struct key *key) |
472 | { |
473 | return key_read_state(key) == KEY_IS_POSITIVE; |
474 | } |
475 | |
476 | static inline bool key_is_negative(const struct key *key) |
477 | { |
478 | return key_read_state(key) < 0; |
479 | } |
480 | |
481 | #define dereference_key_rcu(KEY) \ |
482 | (rcu_dereference((KEY)->payload.rcu_data0)) |
483 | |
484 | #define dereference_key_locked(KEY) \ |
485 | (rcu_dereference_protected((KEY)->payload.rcu_data0, \ |
486 | rwsem_is_locked(&((struct key *)(KEY))->sem))) |
487 | |
488 | #define rcu_assign_keypointer(KEY, PAYLOAD) \ |
489 | do { \ |
490 | rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \ |
491 | } while (0) |
492 | |
493 | /* |
494 | * the userspace interface |
495 | */ |
496 | extern int install_thread_keyring_to_cred(struct cred *cred); |
497 | extern void key_fsuid_changed(struct cred *new_cred); |
498 | extern void key_fsgid_changed(struct cred *new_cred); |
499 | extern void key_init(void); |
500 | |
501 | #else /* CONFIG_KEYS */ |
502 | |
503 | #define key_validate(k) 0 |
504 | #define key_serial(k) 0 |
505 | #define key_get(k) ({ NULL; }) |
506 | #define key_revoke(k) do { } while(0) |
507 | #define key_invalidate(k) do { } while(0) |
508 | #define key_put(k) do { } while(0) |
509 | #define key_ref_put(k) do { } while(0) |
510 | #define make_key_ref(k, p) NULL |
511 | #define key_ref_to_ptr(k) NULL |
512 | #define is_key_possessed(k) 0 |
513 | #define key_fsuid_changed(c) do { } while(0) |
514 | #define key_fsgid_changed(c) do { } while(0) |
515 | #define key_init() do { } while(0) |
516 | #define key_free_user_ns(ns) do { } while(0) |
517 | #define key_remove_domain(d) do { } while(0) |
518 | #define key_lookup(k) NULL |
519 | |
520 | #endif /* CONFIG_KEYS */ |
521 | #endif /* __KERNEL__ */ |
522 | #endif /* _LINUX_KEY_H */ |
523 | |