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