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