Commit | Line | Data |
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973c9f4f | 1 | /* Manage a process's keyrings |
1da177e4 | 2 | * |
69664cf1 | 3 | * Copyright (C) 2004-2005, 2008 Red Hat, Inc. All Rights Reserved. |
1da177e4 LT |
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 | #include <linux/module.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/sched.h> | |
1da177e4 LT |
15 | #include <linux/keyctl.h> |
16 | #include <linux/fs.h> | |
17 | #include <linux/err.h> | |
bb003079 | 18 | #include <linux/mutex.h> |
ee18d64c | 19 | #include <linux/security.h> |
1d1e9756 | 20 | #include <linux/user_namespace.h> |
1da177e4 LT |
21 | #include <asm/uaccess.h> |
22 | #include "internal.h" | |
23 | ||
973c9f4f | 24 | /* Session keyring create vs join semaphore */ |
bb003079 | 25 | static DEFINE_MUTEX(key_session_mutex); |
1da177e4 | 26 | |
973c9f4f | 27 | /* User keyring creation semaphore */ |
69664cf1 DH |
28 | static DEFINE_MUTEX(key_user_keyring_mutex); |
29 | ||
973c9f4f | 30 | /* The root user's tracking struct */ |
1da177e4 LT |
31 | struct key_user root_key_user = { |
32 | .usage = ATOMIC_INIT(3), | |
76181c13 | 33 | .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock), |
6cfd76a2 | 34 | .lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock), |
1da177e4 LT |
35 | .nkeys = ATOMIC_INIT(2), |
36 | .nikeys = ATOMIC_INIT(2), | |
9a56c2db | 37 | .uid = GLOBAL_ROOT_UID, |
1da177e4 LT |
38 | }; |
39 | ||
1da177e4 | 40 | /* |
973c9f4f | 41 | * Install the user and user session keyrings for the current process's UID. |
1da177e4 | 42 | */ |
8bbf4976 | 43 | int install_user_keyrings(void) |
1da177e4 | 44 | { |
d84f4f99 DH |
45 | struct user_struct *user; |
46 | const struct cred *cred; | |
1da177e4 | 47 | struct key *uid_keyring, *session_keyring; |
96b5c8fe | 48 | key_perm_t user_keyring_perm; |
1da177e4 LT |
49 | char buf[20]; |
50 | int ret; | |
9a56c2db | 51 | uid_t uid; |
1da177e4 | 52 | |
96b5c8fe | 53 | user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL; |
d84f4f99 DH |
54 | cred = current_cred(); |
55 | user = cred->user; | |
9a56c2db | 56 | uid = from_kuid(cred->user_ns, user->uid); |
d84f4f99 | 57 | |
9a56c2db | 58 | kenter("%p{%u}", user, uid); |
1da177e4 | 59 | |
0da9dfdd | 60 | if (user->uid_keyring && user->session_keyring) { |
69664cf1 DH |
61 | kleave(" = 0 [exist]"); |
62 | return 0; | |
1da177e4 LT |
63 | } |
64 | ||
69664cf1 DH |
65 | mutex_lock(&key_user_keyring_mutex); |
66 | ret = 0; | |
1da177e4 | 67 | |
69664cf1 DH |
68 | if (!user->uid_keyring) { |
69 | /* get the UID-specific keyring | |
70 | * - there may be one in existence already as it may have been | |
71 | * pinned by a session, but the user_struct pointing to it | |
72 | * may have been destroyed by setuid */ | |
9a56c2db | 73 | sprintf(buf, "_uid.%u", uid); |
69664cf1 DH |
74 | |
75 | uid_keyring = find_keyring_by_name(buf, true); | |
76 | if (IS_ERR(uid_keyring)) { | |
9a56c2db | 77 | uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID, |
96b5c8fe DH |
78 | cred, user_keyring_perm, |
79 | KEY_ALLOC_IN_QUOTA, NULL); | |
69664cf1 DH |
80 | if (IS_ERR(uid_keyring)) { |
81 | ret = PTR_ERR(uid_keyring); | |
82 | goto error; | |
83 | } | |
84 | } | |
85 | ||
86 | /* get a default session keyring (which might also exist | |
87 | * already) */ | |
9a56c2db | 88 | sprintf(buf, "_uid_ses.%u", uid); |
69664cf1 DH |
89 | |
90 | session_keyring = find_keyring_by_name(buf, true); | |
91 | if (IS_ERR(session_keyring)) { | |
92 | session_keyring = | |
9a56c2db | 93 | keyring_alloc(buf, user->uid, INVALID_GID, |
96b5c8fe DH |
94 | cred, user_keyring_perm, |
95 | KEY_ALLOC_IN_QUOTA, NULL); | |
69664cf1 DH |
96 | if (IS_ERR(session_keyring)) { |
97 | ret = PTR_ERR(session_keyring); | |
98 | goto error_release; | |
99 | } | |
100 | ||
101 | /* we install a link from the user session keyring to | |
102 | * the user keyring */ | |
103 | ret = key_link(session_keyring, uid_keyring); | |
104 | if (ret < 0) | |
105 | goto error_release_both; | |
106 | } | |
107 | ||
108 | /* install the keyrings */ | |
109 | user->uid_keyring = uid_keyring; | |
110 | user->session_keyring = session_keyring; | |
1da177e4 LT |
111 | } |
112 | ||
69664cf1 DH |
113 | mutex_unlock(&key_user_keyring_mutex); |
114 | kleave(" = 0"); | |
115 | return 0; | |
1da177e4 | 116 | |
69664cf1 DH |
117 | error_release_both: |
118 | key_put(session_keyring); | |
119 | error_release: | |
120 | key_put(uid_keyring); | |
664cceb0 | 121 | error: |
69664cf1 DH |
122 | mutex_unlock(&key_user_keyring_mutex); |
123 | kleave(" = %d", ret); | |
1da177e4 | 124 | return ret; |
69664cf1 | 125 | } |
1da177e4 | 126 | |
1da177e4 | 127 | /* |
973c9f4f DH |
128 | * Install a fresh thread keyring directly to new credentials. This keyring is |
129 | * allowed to overrun the quota. | |
1da177e4 | 130 | */ |
d84f4f99 | 131 | int install_thread_keyring_to_cred(struct cred *new) |
1da177e4 | 132 | { |
d84f4f99 | 133 | struct key *keyring; |
1da177e4 | 134 | |
d84f4f99 | 135 | keyring = keyring_alloc("_tid", new->uid, new->gid, new, |
96b5c8fe | 136 | KEY_POS_ALL | KEY_USR_VIEW, |
d84f4f99 DH |
137 | KEY_ALLOC_QUOTA_OVERRUN, NULL); |
138 | if (IS_ERR(keyring)) | |
139 | return PTR_ERR(keyring); | |
1da177e4 | 140 | |
d84f4f99 DH |
141 | new->thread_keyring = keyring; |
142 | return 0; | |
143 | } | |
1da177e4 | 144 | |
1da177e4 | 145 | /* |
973c9f4f | 146 | * Install a fresh thread keyring, discarding the old one. |
1da177e4 | 147 | */ |
d84f4f99 | 148 | static int install_thread_keyring(void) |
1da177e4 | 149 | { |
d84f4f99 | 150 | struct cred *new; |
1da177e4 LT |
151 | int ret; |
152 | ||
d84f4f99 DH |
153 | new = prepare_creds(); |
154 | if (!new) | |
155 | return -ENOMEM; | |
1da177e4 | 156 | |
d84f4f99 DH |
157 | BUG_ON(new->thread_keyring); |
158 | ||
159 | ret = install_thread_keyring_to_cred(new); | |
160 | if (ret < 0) { | |
161 | abort_creds(new); | |
162 | return ret; | |
1da177e4 LT |
163 | } |
164 | ||
d84f4f99 DH |
165 | return commit_creds(new); |
166 | } | |
1da177e4 | 167 | |
d84f4f99 | 168 | /* |
973c9f4f DH |
169 | * Install a process keyring directly to a credentials struct. |
170 | * | |
171 | * Returns -EEXIST if there was already a process keyring, 0 if one installed, | |
172 | * and other value on any other error | |
d84f4f99 DH |
173 | */ |
174 | int install_process_keyring_to_cred(struct cred *new) | |
175 | { | |
176 | struct key *keyring; | |
1da177e4 | 177 | |
3a50597d | 178 | if (new->process_keyring) |
d84f4f99 DH |
179 | return -EEXIST; |
180 | ||
96b5c8fe DH |
181 | keyring = keyring_alloc("_pid", new->uid, new->gid, new, |
182 | KEY_POS_ALL | KEY_USR_VIEW, | |
183 | KEY_ALLOC_QUOTA_OVERRUN, NULL); | |
d84f4f99 DH |
184 | if (IS_ERR(keyring)) |
185 | return PTR_ERR(keyring); | |
186 | ||
3a50597d DH |
187 | new->process_keyring = keyring; |
188 | return 0; | |
d84f4f99 | 189 | } |
1da177e4 | 190 | |
1da177e4 | 191 | /* |
973c9f4f DH |
192 | * Make sure a process keyring is installed for the current process. The |
193 | * existing process keyring is not replaced. | |
194 | * | |
195 | * Returns 0 if there is a process keyring by the end of this function, some | |
196 | * error otherwise. | |
1da177e4 | 197 | */ |
d84f4f99 | 198 | static int install_process_keyring(void) |
1da177e4 | 199 | { |
d84f4f99 | 200 | struct cred *new; |
1da177e4 LT |
201 | int ret; |
202 | ||
d84f4f99 DH |
203 | new = prepare_creds(); |
204 | if (!new) | |
205 | return -ENOMEM; | |
1da177e4 | 206 | |
d84f4f99 DH |
207 | ret = install_process_keyring_to_cred(new); |
208 | if (ret < 0) { | |
209 | abort_creds(new); | |
27d63798 | 210 | return ret != -EEXIST ? ret : 0; |
1da177e4 LT |
211 | } |
212 | ||
d84f4f99 DH |
213 | return commit_creds(new); |
214 | } | |
1da177e4 | 215 | |
1da177e4 | 216 | /* |
973c9f4f | 217 | * Install a session keyring directly to a credentials struct. |
1da177e4 | 218 | */ |
685bfd2c | 219 | int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) |
1da177e4 | 220 | { |
7e047ef5 | 221 | unsigned long flags; |
1da177e4 | 222 | struct key *old; |
1a26feb9 DH |
223 | |
224 | might_sleep(); | |
1da177e4 LT |
225 | |
226 | /* create an empty session keyring */ | |
227 | if (!keyring) { | |
7e047ef5 | 228 | flags = KEY_ALLOC_QUOTA_OVERRUN; |
3a50597d | 229 | if (cred->session_keyring) |
7e047ef5 DH |
230 | flags = KEY_ALLOC_IN_QUOTA; |
231 | ||
96b5c8fe DH |
232 | keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred, |
233 | KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ, | |
234 | flags, NULL); | |
1a26feb9 DH |
235 | if (IS_ERR(keyring)) |
236 | return PTR_ERR(keyring); | |
d84f4f99 | 237 | } else { |
ccc3e6d9 | 238 | __key_get(keyring); |
1da177e4 LT |
239 | } |
240 | ||
241 | /* install the keyring */ | |
3a50597d DH |
242 | old = cred->session_keyring; |
243 | rcu_assign_pointer(cred->session_keyring, keyring); | |
244 | ||
245 | if (old) | |
1a26feb9 | 246 | key_put(old); |
1da177e4 | 247 | |
1a26feb9 | 248 | return 0; |
d84f4f99 | 249 | } |
1da177e4 | 250 | |
1da177e4 | 251 | /* |
973c9f4f DH |
252 | * Install a session keyring, discarding the old one. If a keyring is not |
253 | * supplied, an empty one is invented. | |
1da177e4 | 254 | */ |
d84f4f99 | 255 | static int install_session_keyring(struct key *keyring) |
1da177e4 | 256 | { |
d84f4f99 DH |
257 | struct cred *new; |
258 | int ret; | |
1da177e4 | 259 | |
d84f4f99 DH |
260 | new = prepare_creds(); |
261 | if (!new) | |
262 | return -ENOMEM; | |
1da177e4 | 263 | |
99599537 | 264 | ret = install_session_keyring_to_cred(new, keyring); |
d84f4f99 DH |
265 | if (ret < 0) { |
266 | abort_creds(new); | |
267 | return ret; | |
268 | } | |
1da177e4 | 269 | |
d84f4f99 DH |
270 | return commit_creds(new); |
271 | } | |
1da177e4 | 272 | |
1da177e4 | 273 | /* |
973c9f4f | 274 | * Handle the fsuid changing. |
1da177e4 LT |
275 | */ |
276 | void key_fsuid_changed(struct task_struct *tsk) | |
277 | { | |
278 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
279 | BUG_ON(!tsk->cred); |
280 | if (tsk->cred->thread_keyring) { | |
281 | down_write(&tsk->cred->thread_keyring->sem); | |
282 | tsk->cred->thread_keyring->uid = tsk->cred->fsuid; | |
283 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 284 | } |
a8b17ed0 | 285 | } |
1da177e4 | 286 | |
1da177e4 | 287 | /* |
973c9f4f | 288 | * Handle the fsgid changing. |
1da177e4 LT |
289 | */ |
290 | void key_fsgid_changed(struct task_struct *tsk) | |
291 | { | |
292 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
293 | BUG_ON(!tsk->cred); |
294 | if (tsk->cred->thread_keyring) { | |
295 | down_write(&tsk->cred->thread_keyring->sem); | |
296 | tsk->cred->thread_keyring->gid = tsk->cred->fsgid; | |
297 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 298 | } |
a8b17ed0 | 299 | } |
1da177e4 | 300 | |
1da177e4 | 301 | /* |
973c9f4f DH |
302 | * Search the process keyrings attached to the supplied cred for the first |
303 | * matching key. | |
304 | * | |
305 | * The search criteria are the type and the match function. The description is | |
306 | * given to the match function as a parameter, but doesn't otherwise influence | |
307 | * the search. Typically the match function will compare the description | |
308 | * parameter to the key's description. | |
309 | * | |
310 | * This can only search keyrings that grant Search permission to the supplied | |
311 | * credentials. Keyrings linked to searched keyrings will also be searched if | |
312 | * they grant Search permission too. Keys can only be found if they grant | |
313 | * Search permission to the credentials. | |
314 | * | |
315 | * Returns a pointer to the key with the key usage count incremented if | |
316 | * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only | |
317 | * matched negative keys. | |
318 | * | |
319 | * In the case of a successful return, the possession attribute is set on the | |
320 | * returned key reference. | |
1da177e4 | 321 | */ |
4bdf0bc3 | 322 | key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx) |
1da177e4 | 323 | { |
b5f545c8 | 324 | key_ref_t key_ref, ret, err; |
1da177e4 LT |
325 | |
326 | /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were | |
327 | * searchable, but we failed to find a key or we found a negative key; | |
328 | * otherwise we want to return a sample error (probably -EACCES) if | |
329 | * none of the keyrings were searchable | |
330 | * | |
331 | * in terms of priority: success > -ENOKEY > -EAGAIN > other error | |
332 | */ | |
664cceb0 | 333 | key_ref = NULL; |
1da177e4 LT |
334 | ret = NULL; |
335 | err = ERR_PTR(-EAGAIN); | |
336 | ||
337 | /* search the thread keyring first */ | |
4bdf0bc3 | 338 | if (ctx->cred->thread_keyring) { |
664cceb0 | 339 | key_ref = keyring_search_aux( |
4bdf0bc3 | 340 | make_key_ref(ctx->cred->thread_keyring, 1), ctx); |
664cceb0 | 341 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
342 | goto found; |
343 | ||
664cceb0 | 344 | switch (PTR_ERR(key_ref)) { |
1da177e4 | 345 | case -EAGAIN: /* no key */ |
1da177e4 | 346 | case -ENOKEY: /* negative key */ |
664cceb0 | 347 | ret = key_ref; |
1da177e4 LT |
348 | break; |
349 | default: | |
664cceb0 | 350 | err = key_ref; |
1da177e4 LT |
351 | break; |
352 | } | |
353 | } | |
354 | ||
355 | /* search the process keyring second */ | |
4bdf0bc3 | 356 | if (ctx->cred->process_keyring) { |
664cceb0 | 357 | key_ref = keyring_search_aux( |
4bdf0bc3 | 358 | make_key_ref(ctx->cred->process_keyring, 1), ctx); |
664cceb0 | 359 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
360 | goto found; |
361 | ||
664cceb0 | 362 | switch (PTR_ERR(key_ref)) { |
1da177e4 | 363 | case -EAGAIN: /* no key */ |
fe9453a1 DH |
364 | if (ret) |
365 | break; | |
1da177e4 | 366 | case -ENOKEY: /* negative key */ |
664cceb0 | 367 | ret = key_ref; |
1da177e4 LT |
368 | break; |
369 | default: | |
664cceb0 | 370 | err = key_ref; |
1da177e4 LT |
371 | break; |
372 | } | |
373 | } | |
374 | ||
3e30148c | 375 | /* search the session keyring */ |
4bdf0bc3 | 376 | if (ctx->cred->session_keyring) { |
8589b4e0 | 377 | rcu_read_lock(); |
664cceb0 | 378 | key_ref = keyring_search_aux( |
4bdf0bc3 DH |
379 | make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1), |
380 | ctx); | |
8589b4e0 | 381 | rcu_read_unlock(); |
3e30148c | 382 | |
664cceb0 | 383 | if (!IS_ERR(key_ref)) |
3e30148c DH |
384 | goto found; |
385 | ||
664cceb0 | 386 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
387 | case -EAGAIN: /* no key */ |
388 | if (ret) | |
389 | break; | |
390 | case -ENOKEY: /* negative key */ | |
664cceb0 | 391 | ret = key_ref; |
3e30148c DH |
392 | break; |
393 | default: | |
664cceb0 | 394 | err = key_ref; |
3e30148c DH |
395 | break; |
396 | } | |
b5f545c8 DH |
397 | } |
398 | /* or search the user-session keyring */ | |
4bdf0bc3 | 399 | else if (ctx->cred->user->session_keyring) { |
b5f545c8 | 400 | key_ref = keyring_search_aux( |
4bdf0bc3 DH |
401 | make_key_ref(ctx->cred->user->session_keyring, 1), |
402 | ctx); | |
664cceb0 | 403 | if (!IS_ERR(key_ref)) |
3e30148c DH |
404 | goto found; |
405 | ||
664cceb0 | 406 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
407 | case -EAGAIN: /* no key */ |
408 | if (ret) | |
409 | break; | |
410 | case -ENOKEY: /* negative key */ | |
664cceb0 | 411 | ret = key_ref; |
3e30148c DH |
412 | break; |
413 | default: | |
664cceb0 | 414 | err = key_ref; |
3e30148c DH |
415 | break; |
416 | } | |
8589b4e0 | 417 | } |
b5f545c8 | 418 | |
927942aa DH |
419 | /* no key - decide on the error we're going to go for */ |
420 | key_ref = ret ? ret : err; | |
421 | ||
422 | found: | |
423 | return key_ref; | |
424 | } | |
425 | ||
927942aa | 426 | /* |
973c9f4f DH |
427 | * Search the process keyrings attached to the supplied cred for the first |
428 | * matching key in the manner of search_my_process_keyrings(), but also search | |
429 | * the keys attached to the assumed authorisation key using its credentials if | |
430 | * one is available. | |
431 | * | |
432 | * Return same as search_my_process_keyrings(). | |
927942aa | 433 | */ |
4bdf0bc3 | 434 | key_ref_t search_process_keyrings(struct keyring_search_context *ctx) |
927942aa DH |
435 | { |
436 | struct request_key_auth *rka; | |
437 | key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; | |
438 | ||
439 | might_sleep(); | |
440 | ||
4bdf0bc3 | 441 | key_ref = search_my_process_keyrings(ctx); |
927942aa DH |
442 | if (!IS_ERR(key_ref)) |
443 | goto found; | |
444 | err = key_ref; | |
445 | ||
b5f545c8 DH |
446 | /* if this process has an instantiation authorisation key, then we also |
447 | * search the keyrings of the process mentioned there | |
448 | * - we don't permit access to request_key auth keys via this method | |
449 | */ | |
4bdf0bc3 DH |
450 | if (ctx->cred->request_key_auth && |
451 | ctx->cred == current_cred() && | |
452 | ctx->index_key.type != &key_type_request_key_auth | |
b5f545c8 | 453 | ) { |
4bdf0bc3 DH |
454 | const struct cred *cred = ctx->cred; |
455 | ||
04c567d9 | 456 | /* defend against the auth key being revoked */ |
c69e8d9c | 457 | down_read(&cred->request_key_auth->sem); |
b5f545c8 | 458 | |
4bdf0bc3 DH |
459 | if (key_validate(ctx->cred->request_key_auth) == 0) { |
460 | rka = ctx->cred->request_key_auth->payload.data; | |
b5f545c8 | 461 | |
4bdf0bc3 DH |
462 | ctx->cred = rka->cred; |
463 | key_ref = search_process_keyrings(ctx); | |
464 | ctx->cred = cred; | |
1da177e4 | 465 | |
c69e8d9c | 466 | up_read(&cred->request_key_auth->sem); |
04c567d9 DH |
467 | |
468 | if (!IS_ERR(key_ref)) | |
469 | goto found; | |
470 | ||
927942aa | 471 | ret = key_ref; |
04c567d9 | 472 | } else { |
c69e8d9c | 473 | up_read(&cred->request_key_auth->sem); |
3e30148c | 474 | } |
1da177e4 LT |
475 | } |
476 | ||
477 | /* no key - decide on the error we're going to go for */ | |
927942aa DH |
478 | if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY)) |
479 | key_ref = ERR_PTR(-ENOKEY); | |
480 | else if (err == ERR_PTR(-EACCES)) | |
481 | key_ref = ret; | |
482 | else | |
483 | key_ref = err; | |
1da177e4 | 484 | |
3e30148c | 485 | found: |
664cceb0 | 486 | return key_ref; |
a8b17ed0 | 487 | } |
1da177e4 | 488 | |
664cceb0 | 489 | /* |
973c9f4f | 490 | * See if the key we're looking at is the target key. |
664cceb0 | 491 | */ |
0c903ab6 DH |
492 | bool lookup_user_key_possessed(const struct key *key, |
493 | const struct key_match_data *match_data) | |
664cceb0 | 494 | { |
46291959 | 495 | return key == match_data->raw_data; |
a8b17ed0 | 496 | } |
664cceb0 | 497 | |
1da177e4 | 498 | /* |
973c9f4f DH |
499 | * Look up a key ID given us by userspace with a given permissions mask to get |
500 | * the key it refers to. | |
501 | * | |
502 | * Flags can be passed to request that special keyrings be created if referred | |
503 | * to directly, to permit partially constructed keys to be found and to skip | |
504 | * validity and permission checks on the found key. | |
505 | * | |
506 | * Returns a pointer to the key with an incremented usage count if successful; | |
507 | * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond | |
508 | * to a key or the best found key was a negative key; -EKEYREVOKED or | |
509 | * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the | |
510 | * found key doesn't grant the requested permit or the LSM denied access to it; | |
511 | * or -ENOMEM if a special keyring couldn't be created. | |
512 | * | |
513 | * In the case of a successful return, the possession attribute is set on the | |
514 | * returned key reference. | |
1da177e4 | 515 | */ |
5593122e | 516 | key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, |
8bbf4976 | 517 | key_perm_t perm) |
1da177e4 | 518 | { |
4bdf0bc3 | 519 | struct keyring_search_context ctx = { |
46291959 DH |
520 | .match_data.cmp = lookup_user_key_possessed, |
521 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
522 | .flags = KEYRING_SEARCH_NO_STATE_CHECK, | |
4bdf0bc3 | 523 | }; |
8bbf4976 | 524 | struct request_key_auth *rka; |
1da177e4 | 525 | struct key *key; |
b6dff3ec | 526 | key_ref_t key_ref, skey_ref; |
1da177e4 LT |
527 | int ret; |
528 | ||
bb952bb9 | 529 | try_again: |
4bdf0bc3 | 530 | ctx.cred = get_current_cred(); |
664cceb0 | 531 | key_ref = ERR_PTR(-ENOKEY); |
1da177e4 LT |
532 | |
533 | switch (id) { | |
534 | case KEY_SPEC_THREAD_KEYRING: | |
4bdf0bc3 | 535 | if (!ctx.cred->thread_keyring) { |
5593122e | 536 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
537 | goto error; |
538 | ||
8bbf4976 | 539 | ret = install_thread_keyring(); |
1da177e4 | 540 | if (ret < 0) { |
4d09ec0f | 541 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
542 | goto error; |
543 | } | |
bb952bb9 | 544 | goto reget_creds; |
1da177e4 LT |
545 | } |
546 | ||
4bdf0bc3 | 547 | key = ctx.cred->thread_keyring; |
ccc3e6d9 | 548 | __key_get(key); |
664cceb0 | 549 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
550 | break; |
551 | ||
552 | case KEY_SPEC_PROCESS_KEYRING: | |
4bdf0bc3 | 553 | if (!ctx.cred->process_keyring) { |
5593122e | 554 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
555 | goto error; |
556 | ||
8bbf4976 | 557 | ret = install_process_keyring(); |
1da177e4 | 558 | if (ret < 0) { |
4d09ec0f | 559 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
560 | goto error; |
561 | } | |
bb952bb9 | 562 | goto reget_creds; |
1da177e4 LT |
563 | } |
564 | ||
4bdf0bc3 | 565 | key = ctx.cred->process_keyring; |
ccc3e6d9 | 566 | __key_get(key); |
664cceb0 | 567 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
568 | break; |
569 | ||
570 | case KEY_SPEC_SESSION_KEYRING: | |
4bdf0bc3 | 571 | if (!ctx.cred->session_keyring) { |
1da177e4 LT |
572 | /* always install a session keyring upon access if one |
573 | * doesn't exist yet */ | |
8bbf4976 | 574 | ret = install_user_keyrings(); |
69664cf1 DH |
575 | if (ret < 0) |
576 | goto error; | |
3ecf1b4f DH |
577 | if (lflags & KEY_LOOKUP_CREATE) |
578 | ret = join_session_keyring(NULL); | |
579 | else | |
580 | ret = install_session_keyring( | |
4bdf0bc3 | 581 | ctx.cred->user->session_keyring); |
d84f4f99 | 582 | |
1da177e4 LT |
583 | if (ret < 0) |
584 | goto error; | |
bb952bb9 | 585 | goto reget_creds; |
4bdf0bc3 DH |
586 | } else if (ctx.cred->session_keyring == |
587 | ctx.cred->user->session_keyring && | |
3ecf1b4f DH |
588 | lflags & KEY_LOOKUP_CREATE) { |
589 | ret = join_session_keyring(NULL); | |
590 | if (ret < 0) | |
591 | goto error; | |
592 | goto reget_creds; | |
1da177e4 LT |
593 | } |
594 | ||
3e30148c | 595 | rcu_read_lock(); |
4bdf0bc3 | 596 | key = rcu_dereference(ctx.cred->session_keyring); |
ccc3e6d9 | 597 | __key_get(key); |
3e30148c | 598 | rcu_read_unlock(); |
664cceb0 | 599 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
600 | break; |
601 | ||
602 | case KEY_SPEC_USER_KEYRING: | |
4bdf0bc3 | 603 | if (!ctx.cred->user->uid_keyring) { |
8bbf4976 | 604 | ret = install_user_keyrings(); |
69664cf1 DH |
605 | if (ret < 0) |
606 | goto error; | |
607 | } | |
608 | ||
4bdf0bc3 | 609 | key = ctx.cred->user->uid_keyring; |
ccc3e6d9 | 610 | __key_get(key); |
664cceb0 | 611 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
612 | break; |
613 | ||
614 | case KEY_SPEC_USER_SESSION_KEYRING: | |
4bdf0bc3 | 615 | if (!ctx.cred->user->session_keyring) { |
8bbf4976 | 616 | ret = install_user_keyrings(); |
69664cf1 DH |
617 | if (ret < 0) |
618 | goto error; | |
619 | } | |
620 | ||
4bdf0bc3 | 621 | key = ctx.cred->user->session_keyring; |
ccc3e6d9 | 622 | __key_get(key); |
664cceb0 | 623 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
624 | break; |
625 | ||
626 | case KEY_SPEC_GROUP_KEYRING: | |
627 | /* group keyrings are not yet supported */ | |
4d09ec0f | 628 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
629 | goto error; |
630 | ||
b5f545c8 | 631 | case KEY_SPEC_REQKEY_AUTH_KEY: |
4bdf0bc3 | 632 | key = ctx.cred->request_key_auth; |
b5f545c8 DH |
633 | if (!key) |
634 | goto error; | |
635 | ||
ccc3e6d9 | 636 | __key_get(key); |
b5f545c8 DH |
637 | key_ref = make_key_ref(key, 1); |
638 | break; | |
639 | ||
8bbf4976 | 640 | case KEY_SPEC_REQUESTOR_KEYRING: |
4bdf0bc3 | 641 | if (!ctx.cred->request_key_auth) |
8bbf4976 DH |
642 | goto error; |
643 | ||
4bdf0bc3 | 644 | down_read(&ctx.cred->request_key_auth->sem); |
f67dabbd | 645 | if (test_bit(KEY_FLAG_REVOKED, |
4bdf0bc3 | 646 | &ctx.cred->request_key_auth->flags)) { |
8bbf4976 DH |
647 | key_ref = ERR_PTR(-EKEYREVOKED); |
648 | key = NULL; | |
649 | } else { | |
4bdf0bc3 | 650 | rka = ctx.cred->request_key_auth->payload.data; |
8bbf4976 | 651 | key = rka->dest_keyring; |
ccc3e6d9 | 652 | __key_get(key); |
8bbf4976 | 653 | } |
4bdf0bc3 | 654 | up_read(&ctx.cred->request_key_auth->sem); |
8bbf4976 DH |
655 | if (!key) |
656 | goto error; | |
657 | key_ref = make_key_ref(key, 1); | |
658 | break; | |
659 | ||
1da177e4 | 660 | default: |
664cceb0 | 661 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
662 | if (id < 1) |
663 | goto error; | |
664 | ||
665 | key = key_lookup(id); | |
664cceb0 | 666 | if (IS_ERR(key)) { |
e231c2ee | 667 | key_ref = ERR_CAST(key); |
1da177e4 | 668 | goto error; |
664cceb0 DH |
669 | } |
670 | ||
671 | key_ref = make_key_ref(key, 0); | |
672 | ||
673 | /* check to see if we possess the key */ | |
4bdf0bc3 DH |
674 | ctx.index_key.type = key->type; |
675 | ctx.index_key.description = key->description; | |
676 | ctx.index_key.desc_len = strlen(key->description); | |
46291959 | 677 | ctx.match_data.raw_data = key; |
4bdf0bc3 DH |
678 | kdebug("check possessed"); |
679 | skey_ref = search_process_keyrings(&ctx); | |
680 | kdebug("possessed=%p", skey_ref); | |
664cceb0 DH |
681 | |
682 | if (!IS_ERR(skey_ref)) { | |
683 | key_put(key); | |
684 | key_ref = skey_ref; | |
685 | } | |
686 | ||
1da177e4 LT |
687 | break; |
688 | } | |
689 | ||
5593122e DH |
690 | /* unlink does not use the nominated key in any way, so can skip all |
691 | * the permission checks as it is only concerned with the keyring */ | |
692 | if (lflags & KEY_LOOKUP_FOR_UNLINK) { | |
693 | ret = 0; | |
694 | goto error; | |
695 | } | |
696 | ||
697 | if (!(lflags & KEY_LOOKUP_PARTIAL)) { | |
76181c13 DH |
698 | ret = wait_for_key_construction(key, true); |
699 | switch (ret) { | |
700 | case -ERESTARTSYS: | |
701 | goto invalid_key; | |
702 | default: | |
703 | if (perm) | |
704 | goto invalid_key; | |
705 | case 0: | |
706 | break; | |
707 | } | |
708 | } else if (perm) { | |
1da177e4 LT |
709 | ret = key_validate(key); |
710 | if (ret < 0) | |
711 | goto invalid_key; | |
712 | } | |
713 | ||
714 | ret = -EIO; | |
5593122e DH |
715 | if (!(lflags & KEY_LOOKUP_PARTIAL) && |
716 | !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) | |
1da177e4 LT |
717 | goto invalid_key; |
718 | ||
3e30148c | 719 | /* check the permissions */ |
4bdf0bc3 | 720 | ret = key_task_permission(key_ref, ctx.cred, perm); |
29db9190 | 721 | if (ret < 0) |
1da177e4 LT |
722 | goto invalid_key; |
723 | ||
31d5a79d DH |
724 | key->last_used_at = current_kernel_time().tv_sec; |
725 | ||
664cceb0 | 726 | error: |
4bdf0bc3 | 727 | put_cred(ctx.cred); |
664cceb0 | 728 | return key_ref; |
1da177e4 | 729 | |
664cceb0 DH |
730 | invalid_key: |
731 | key_ref_put(key_ref); | |
732 | key_ref = ERR_PTR(ret); | |
1da177e4 LT |
733 | goto error; |
734 | ||
bb952bb9 DH |
735 | /* if we attempted to install a keyring, then it may have caused new |
736 | * creds to be installed */ | |
737 | reget_creds: | |
4bdf0bc3 | 738 | put_cred(ctx.cred); |
bb952bb9 | 739 | goto try_again; |
a8b17ed0 | 740 | } |
bb952bb9 | 741 | |
1da177e4 | 742 | /* |
973c9f4f DH |
743 | * Join the named keyring as the session keyring if possible else attempt to |
744 | * create a new one of that name and join that. | |
745 | * | |
746 | * If the name is NULL, an empty anonymous keyring will be installed as the | |
747 | * session keyring. | |
748 | * | |
749 | * Named session keyrings are joined with a semaphore held to prevent the | |
750 | * keyrings from going away whilst the attempt is made to going them and also | |
751 | * to prevent a race in creating compatible session keyrings. | |
1da177e4 LT |
752 | */ |
753 | long join_session_keyring(const char *name) | |
754 | { | |
d84f4f99 DH |
755 | const struct cred *old; |
756 | struct cred *new; | |
1da177e4 | 757 | struct key *keyring; |
d84f4f99 DH |
758 | long ret, serial; |
759 | ||
d84f4f99 DH |
760 | new = prepare_creds(); |
761 | if (!new) | |
762 | return -ENOMEM; | |
763 | old = current_cred(); | |
1da177e4 LT |
764 | |
765 | /* if no name is provided, install an anonymous keyring */ | |
766 | if (!name) { | |
d84f4f99 | 767 | ret = install_session_keyring_to_cred(new, NULL); |
1da177e4 LT |
768 | if (ret < 0) |
769 | goto error; | |
770 | ||
3a50597d | 771 | serial = new->session_keyring->serial; |
d84f4f99 DH |
772 | ret = commit_creds(new); |
773 | if (ret == 0) | |
774 | ret = serial; | |
775 | goto okay; | |
1da177e4 LT |
776 | } |
777 | ||
778 | /* allow the user to join or create a named keyring */ | |
bb003079 | 779 | mutex_lock(&key_session_mutex); |
1da177e4 LT |
780 | |
781 | /* look for an existing keyring of this name */ | |
69664cf1 | 782 | keyring = find_keyring_by_name(name, false); |
1da177e4 LT |
783 | if (PTR_ERR(keyring) == -ENOKEY) { |
784 | /* not found - try and create a new one */ | |
96b5c8fe DH |
785 | keyring = keyring_alloc( |
786 | name, old->uid, old->gid, old, | |
787 | KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK, | |
788 | KEY_ALLOC_IN_QUOTA, NULL); | |
1da177e4 LT |
789 | if (IS_ERR(keyring)) { |
790 | ret = PTR_ERR(keyring); | |
bcf945d3 | 791 | goto error2; |
1da177e4 | 792 | } |
d84f4f99 | 793 | } else if (IS_ERR(keyring)) { |
1da177e4 LT |
794 | ret = PTR_ERR(keyring); |
795 | goto error2; | |
3a50597d DH |
796 | } else if (keyring == new->session_keyring) { |
797 | ret = 0; | |
798 | goto error2; | |
1da177e4 LT |
799 | } |
800 | ||
801 | /* we've got a keyring - now to install it */ | |
d84f4f99 | 802 | ret = install_session_keyring_to_cred(new, keyring); |
1da177e4 LT |
803 | if (ret < 0) |
804 | goto error2; | |
805 | ||
d84f4f99 DH |
806 | commit_creds(new); |
807 | mutex_unlock(&key_session_mutex); | |
808 | ||
1da177e4 LT |
809 | ret = keyring->serial; |
810 | key_put(keyring); | |
d84f4f99 DH |
811 | okay: |
812 | return ret; | |
1da177e4 | 813 | |
664cceb0 | 814 | error2: |
bb003079 | 815 | mutex_unlock(&key_session_mutex); |
664cceb0 | 816 | error: |
d84f4f99 | 817 | abort_creds(new); |
1da177e4 | 818 | return ret; |
d84f4f99 | 819 | } |
ee18d64c DH |
820 | |
821 | /* | |
973c9f4f DH |
822 | * Replace a process's session keyring on behalf of one of its children when |
823 | * the target process is about to resume userspace execution. | |
ee18d64c | 824 | */ |
67d12145 | 825 | void key_change_session_keyring(struct callback_head *twork) |
ee18d64c | 826 | { |
413cd3d9 | 827 | const struct cred *old = current_cred(); |
67d12145 | 828 | struct cred *new = container_of(twork, struct cred, rcu); |
ee18d64c | 829 | |
413cd3d9 ON |
830 | if (unlikely(current->flags & PF_EXITING)) { |
831 | put_cred(new); | |
ee18d64c | 832 | return; |
413cd3d9 | 833 | } |
ee18d64c | 834 | |
ee18d64c DH |
835 | new-> uid = old-> uid; |
836 | new-> euid = old-> euid; | |
837 | new-> suid = old-> suid; | |
838 | new->fsuid = old->fsuid; | |
839 | new-> gid = old-> gid; | |
840 | new-> egid = old-> egid; | |
841 | new-> sgid = old-> sgid; | |
842 | new->fsgid = old->fsgid; | |
843 | new->user = get_uid(old->user); | |
ba0e3427 | 844 | new->user_ns = get_user_ns(old->user_ns); |
ee18d64c DH |
845 | new->group_info = get_group_info(old->group_info); |
846 | ||
847 | new->securebits = old->securebits; | |
848 | new->cap_inheritable = old->cap_inheritable; | |
849 | new->cap_permitted = old->cap_permitted; | |
850 | new->cap_effective = old->cap_effective; | |
58319057 | 851 | new->cap_ambient = old->cap_ambient; |
ee18d64c DH |
852 | new->cap_bset = old->cap_bset; |
853 | ||
854 | new->jit_keyring = old->jit_keyring; | |
855 | new->thread_keyring = key_get(old->thread_keyring); | |
3a50597d | 856 | new->process_keyring = key_get(old->process_keyring); |
ee18d64c DH |
857 | |
858 | security_transfer_creds(new, old); | |
859 | ||
860 | commit_creds(new); | |
861 | } | |
c124bde2 MZ |
862 | |
863 | /* | |
864 | * Make sure that root's user and user-session keyrings exist. | |
865 | */ | |
866 | static int __init init_root_keyring(void) | |
867 | { | |
868 | return install_user_keyrings(); | |
869 | } | |
870 | ||
871 | late_initcall(init_root_keyring); |