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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> |
7c0f6ba6 | 21 | #include <linux/uaccess.h> |
1da177e4 LT |
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 | 78 | cred, user_keyring_perm, |
5ac7eace DH |
79 | KEY_ALLOC_IN_QUOTA, |
80 | NULL, NULL); | |
69664cf1 DH |
81 | if (IS_ERR(uid_keyring)) { |
82 | ret = PTR_ERR(uid_keyring); | |
83 | goto error; | |
84 | } | |
85 | } | |
86 | ||
87 | /* get a default session keyring (which might also exist | |
88 | * already) */ | |
9a56c2db | 89 | sprintf(buf, "_uid_ses.%u", uid); |
69664cf1 DH |
90 | |
91 | session_keyring = find_keyring_by_name(buf, true); | |
92 | if (IS_ERR(session_keyring)) { | |
93 | session_keyring = | |
9a56c2db | 94 | keyring_alloc(buf, user->uid, INVALID_GID, |
96b5c8fe | 95 | cred, user_keyring_perm, |
5ac7eace DH |
96 | KEY_ALLOC_IN_QUOTA, |
97 | NULL, NULL); | |
69664cf1 DH |
98 | if (IS_ERR(session_keyring)) { |
99 | ret = PTR_ERR(session_keyring); | |
100 | goto error_release; | |
101 | } | |
102 | ||
103 | /* we install a link from the user session keyring to | |
104 | * the user keyring */ | |
105 | ret = key_link(session_keyring, uid_keyring); | |
106 | if (ret < 0) | |
107 | goto error_release_both; | |
108 | } | |
109 | ||
110 | /* install the keyrings */ | |
111 | user->uid_keyring = uid_keyring; | |
112 | user->session_keyring = session_keyring; | |
1da177e4 LT |
113 | } |
114 | ||
69664cf1 DH |
115 | mutex_unlock(&key_user_keyring_mutex); |
116 | kleave(" = 0"); | |
117 | return 0; | |
1da177e4 | 118 | |
69664cf1 DH |
119 | error_release_both: |
120 | key_put(session_keyring); | |
121 | error_release: | |
122 | key_put(uid_keyring); | |
664cceb0 | 123 | error: |
69664cf1 DH |
124 | mutex_unlock(&key_user_keyring_mutex); |
125 | kleave(" = %d", ret); | |
1da177e4 | 126 | return ret; |
69664cf1 | 127 | } |
1da177e4 | 128 | |
1da177e4 | 129 | /* |
4a09908e EB |
130 | * Install a thread keyring to the given credentials struct if it didn't have |
131 | * one already. This is allowed to overrun the quota. | |
132 | * | |
133 | * Return: 0 if a thread keyring is now present; -errno on failure. | |
1da177e4 | 134 | */ |
d84f4f99 | 135 | int install_thread_keyring_to_cred(struct cred *new) |
1da177e4 | 136 | { |
d84f4f99 | 137 | struct key *keyring; |
1da177e4 | 138 | |
4a09908e EB |
139 | if (new->thread_keyring) |
140 | return 0; | |
141 | ||
d84f4f99 | 142 | keyring = keyring_alloc("_tid", new->uid, new->gid, new, |
96b5c8fe | 143 | KEY_POS_ALL | KEY_USR_VIEW, |
5ac7eace DH |
144 | KEY_ALLOC_QUOTA_OVERRUN, |
145 | NULL, NULL); | |
d84f4f99 DH |
146 | if (IS_ERR(keyring)) |
147 | return PTR_ERR(keyring); | |
1da177e4 | 148 | |
d84f4f99 DH |
149 | new->thread_keyring = keyring; |
150 | return 0; | |
151 | } | |
1da177e4 | 152 | |
1da177e4 | 153 | /* |
4a09908e EB |
154 | * Install a thread keyring to the current task if it didn't have one already. |
155 | * | |
156 | * Return: 0 if a thread keyring is now present; -errno on failure. | |
1da177e4 | 157 | */ |
d84f4f99 | 158 | static int install_thread_keyring(void) |
1da177e4 | 159 | { |
d84f4f99 | 160 | struct cred *new; |
1da177e4 LT |
161 | int ret; |
162 | ||
d84f4f99 DH |
163 | new = prepare_creds(); |
164 | if (!new) | |
165 | return -ENOMEM; | |
1da177e4 | 166 | |
d84f4f99 DH |
167 | ret = install_thread_keyring_to_cred(new); |
168 | if (ret < 0) { | |
169 | abort_creds(new); | |
170 | return ret; | |
1da177e4 LT |
171 | } |
172 | ||
d84f4f99 DH |
173 | return commit_creds(new); |
174 | } | |
1da177e4 | 175 | |
d84f4f99 | 176 | /* |
4a09908e EB |
177 | * Install a process keyring to the given credentials struct if it didn't have |
178 | * one already. This is allowed to overrun the quota. | |
973c9f4f | 179 | * |
4a09908e | 180 | * Return: 0 if a process keyring is now present; -errno on failure. |
d84f4f99 DH |
181 | */ |
182 | int install_process_keyring_to_cred(struct cred *new) | |
183 | { | |
184 | struct key *keyring; | |
1da177e4 | 185 | |
3a50597d | 186 | if (new->process_keyring) |
4a09908e | 187 | return 0; |
d84f4f99 | 188 | |
96b5c8fe DH |
189 | keyring = keyring_alloc("_pid", new->uid, new->gid, new, |
190 | KEY_POS_ALL | KEY_USR_VIEW, | |
5ac7eace DH |
191 | KEY_ALLOC_QUOTA_OVERRUN, |
192 | NULL, NULL); | |
d84f4f99 DH |
193 | if (IS_ERR(keyring)) |
194 | return PTR_ERR(keyring); | |
195 | ||
3a50597d DH |
196 | new->process_keyring = keyring; |
197 | return 0; | |
d84f4f99 | 198 | } |
1da177e4 | 199 | |
1da177e4 | 200 | /* |
4a09908e | 201 | * Install a process keyring to the current task if it didn't have one already. |
973c9f4f | 202 | * |
4a09908e | 203 | * Return: 0 if a process keyring is now present; -errno on failure. |
1da177e4 | 204 | */ |
d84f4f99 | 205 | static int install_process_keyring(void) |
1da177e4 | 206 | { |
d84f4f99 | 207 | struct cred *new; |
1da177e4 LT |
208 | int ret; |
209 | ||
d84f4f99 DH |
210 | new = prepare_creds(); |
211 | if (!new) | |
212 | return -ENOMEM; | |
1da177e4 | 213 | |
d84f4f99 DH |
214 | ret = install_process_keyring_to_cred(new); |
215 | if (ret < 0) { | |
216 | abort_creds(new); | |
4a09908e | 217 | return ret; |
1da177e4 LT |
218 | } |
219 | ||
d84f4f99 DH |
220 | return commit_creds(new); |
221 | } | |
1da177e4 | 222 | |
1da177e4 | 223 | /* |
4a09908e EB |
224 | * Install the given keyring as the session keyring of the given credentials |
225 | * struct, replacing the existing one if any. If the given keyring is NULL, | |
226 | * then install a new anonymous session keyring. | |
227 | * | |
228 | * Return: 0 on success; -errno on failure. | |
1da177e4 | 229 | */ |
685bfd2c | 230 | int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) |
1da177e4 | 231 | { |
7e047ef5 | 232 | unsigned long flags; |
1da177e4 | 233 | struct key *old; |
1a26feb9 DH |
234 | |
235 | might_sleep(); | |
1da177e4 LT |
236 | |
237 | /* create an empty session keyring */ | |
238 | if (!keyring) { | |
7e047ef5 | 239 | flags = KEY_ALLOC_QUOTA_OVERRUN; |
3a50597d | 240 | if (cred->session_keyring) |
7e047ef5 DH |
241 | flags = KEY_ALLOC_IN_QUOTA; |
242 | ||
96b5c8fe DH |
243 | keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred, |
244 | KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ, | |
5ac7eace | 245 | flags, NULL, NULL); |
1a26feb9 DH |
246 | if (IS_ERR(keyring)) |
247 | return PTR_ERR(keyring); | |
d84f4f99 | 248 | } else { |
ccc3e6d9 | 249 | __key_get(keyring); |
1da177e4 LT |
250 | } |
251 | ||
252 | /* install the keyring */ | |
3a50597d DH |
253 | old = cred->session_keyring; |
254 | rcu_assign_pointer(cred->session_keyring, keyring); | |
255 | ||
256 | if (old) | |
1a26feb9 | 257 | key_put(old); |
1da177e4 | 258 | |
1a26feb9 | 259 | return 0; |
d84f4f99 | 260 | } |
1da177e4 | 261 | |
1da177e4 | 262 | /* |
4a09908e EB |
263 | * Install the given keyring as the session keyring of the current task, |
264 | * replacing the existing one if any. If the given keyring is NULL, then | |
265 | * install a new anonymous session keyring. | |
266 | * | |
267 | * Return: 0 on success; -errno on failure. | |
1da177e4 | 268 | */ |
d84f4f99 | 269 | static int install_session_keyring(struct key *keyring) |
1da177e4 | 270 | { |
d84f4f99 DH |
271 | struct cred *new; |
272 | int ret; | |
1da177e4 | 273 | |
d84f4f99 DH |
274 | new = prepare_creds(); |
275 | if (!new) | |
276 | return -ENOMEM; | |
1da177e4 | 277 | |
99599537 | 278 | ret = install_session_keyring_to_cred(new, keyring); |
d84f4f99 DH |
279 | if (ret < 0) { |
280 | abort_creds(new); | |
281 | return ret; | |
282 | } | |
1da177e4 | 283 | |
d84f4f99 DH |
284 | return commit_creds(new); |
285 | } | |
1da177e4 | 286 | |
1da177e4 | 287 | /* |
973c9f4f | 288 | * Handle the fsuid changing. |
1da177e4 LT |
289 | */ |
290 | void key_fsuid_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->uid = tsk->cred->fsuid; | |
297 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 298 | } |
a8b17ed0 | 299 | } |
1da177e4 | 300 | |
1da177e4 | 301 | /* |
973c9f4f | 302 | * Handle the fsgid changing. |
1da177e4 LT |
303 | */ |
304 | void key_fsgid_changed(struct task_struct *tsk) | |
305 | { | |
306 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
307 | BUG_ON(!tsk->cred); |
308 | if (tsk->cred->thread_keyring) { | |
309 | down_write(&tsk->cred->thread_keyring->sem); | |
310 | tsk->cred->thread_keyring->gid = tsk->cred->fsgid; | |
311 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 312 | } |
a8b17ed0 | 313 | } |
1da177e4 | 314 | |
1da177e4 | 315 | /* |
973c9f4f DH |
316 | * Search the process keyrings attached to the supplied cred for the first |
317 | * matching key. | |
318 | * | |
319 | * The search criteria are the type and the match function. The description is | |
320 | * given to the match function as a parameter, but doesn't otherwise influence | |
321 | * the search. Typically the match function will compare the description | |
322 | * parameter to the key's description. | |
323 | * | |
324 | * This can only search keyrings that grant Search permission to the supplied | |
325 | * credentials. Keyrings linked to searched keyrings will also be searched if | |
326 | * they grant Search permission too. Keys can only be found if they grant | |
327 | * Search permission to the credentials. | |
328 | * | |
329 | * Returns a pointer to the key with the key usage count incremented if | |
330 | * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only | |
331 | * matched negative keys. | |
332 | * | |
333 | * In the case of a successful return, the possession attribute is set on the | |
334 | * returned key reference. | |
1da177e4 | 335 | */ |
4bdf0bc3 | 336 | key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx) |
1da177e4 | 337 | { |
b5f545c8 | 338 | key_ref_t key_ref, ret, err; |
1da177e4 LT |
339 | |
340 | /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were | |
341 | * searchable, but we failed to find a key or we found a negative key; | |
342 | * otherwise we want to return a sample error (probably -EACCES) if | |
343 | * none of the keyrings were searchable | |
344 | * | |
345 | * in terms of priority: success > -ENOKEY > -EAGAIN > other error | |
346 | */ | |
664cceb0 | 347 | key_ref = NULL; |
1da177e4 LT |
348 | ret = NULL; |
349 | err = ERR_PTR(-EAGAIN); | |
350 | ||
351 | /* search the thread keyring first */ | |
4bdf0bc3 | 352 | if (ctx->cred->thread_keyring) { |
664cceb0 | 353 | key_ref = keyring_search_aux( |
4bdf0bc3 | 354 | make_key_ref(ctx->cred->thread_keyring, 1), ctx); |
664cceb0 | 355 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
356 | goto found; |
357 | ||
664cceb0 | 358 | switch (PTR_ERR(key_ref)) { |
1da177e4 | 359 | case -EAGAIN: /* no key */ |
1da177e4 | 360 | case -ENOKEY: /* negative key */ |
664cceb0 | 361 | ret = key_ref; |
1da177e4 LT |
362 | break; |
363 | default: | |
664cceb0 | 364 | err = key_ref; |
1da177e4 LT |
365 | break; |
366 | } | |
367 | } | |
368 | ||
369 | /* search the process keyring second */ | |
4bdf0bc3 | 370 | if (ctx->cred->process_keyring) { |
664cceb0 | 371 | key_ref = keyring_search_aux( |
4bdf0bc3 | 372 | make_key_ref(ctx->cred->process_keyring, 1), ctx); |
664cceb0 | 373 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
374 | goto found; |
375 | ||
664cceb0 | 376 | switch (PTR_ERR(key_ref)) { |
1da177e4 | 377 | case -EAGAIN: /* no key */ |
fe9453a1 DH |
378 | if (ret) |
379 | break; | |
1da177e4 | 380 | case -ENOKEY: /* negative key */ |
664cceb0 | 381 | ret = key_ref; |
1da177e4 LT |
382 | break; |
383 | default: | |
664cceb0 | 384 | err = key_ref; |
1da177e4 LT |
385 | break; |
386 | } | |
387 | } | |
388 | ||
3e30148c | 389 | /* search the session keyring */ |
4bdf0bc3 | 390 | if (ctx->cred->session_keyring) { |
8589b4e0 | 391 | rcu_read_lock(); |
664cceb0 | 392 | key_ref = keyring_search_aux( |
4bdf0bc3 DH |
393 | make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1), |
394 | ctx); | |
8589b4e0 | 395 | rcu_read_unlock(); |
3e30148c | 396 | |
664cceb0 | 397 | if (!IS_ERR(key_ref)) |
3e30148c DH |
398 | goto found; |
399 | ||
664cceb0 | 400 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
401 | case -EAGAIN: /* no key */ |
402 | if (ret) | |
403 | break; | |
404 | case -ENOKEY: /* negative key */ | |
664cceb0 | 405 | ret = key_ref; |
3e30148c DH |
406 | break; |
407 | default: | |
664cceb0 | 408 | err = key_ref; |
3e30148c DH |
409 | break; |
410 | } | |
b5f545c8 DH |
411 | } |
412 | /* or search the user-session keyring */ | |
4bdf0bc3 | 413 | else if (ctx->cred->user->session_keyring) { |
b5f545c8 | 414 | key_ref = keyring_search_aux( |
4bdf0bc3 DH |
415 | make_key_ref(ctx->cred->user->session_keyring, 1), |
416 | ctx); | |
664cceb0 | 417 | if (!IS_ERR(key_ref)) |
3e30148c DH |
418 | goto found; |
419 | ||
664cceb0 | 420 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
421 | case -EAGAIN: /* no key */ |
422 | if (ret) | |
423 | break; | |
424 | case -ENOKEY: /* negative key */ | |
664cceb0 | 425 | ret = key_ref; |
3e30148c DH |
426 | break; |
427 | default: | |
664cceb0 | 428 | err = key_ref; |
3e30148c DH |
429 | break; |
430 | } | |
8589b4e0 | 431 | } |
b5f545c8 | 432 | |
927942aa DH |
433 | /* no key - decide on the error we're going to go for */ |
434 | key_ref = ret ? ret : err; | |
435 | ||
436 | found: | |
437 | return key_ref; | |
438 | } | |
439 | ||
927942aa | 440 | /* |
973c9f4f DH |
441 | * Search the process keyrings attached to the supplied cred for the first |
442 | * matching key in the manner of search_my_process_keyrings(), but also search | |
443 | * the keys attached to the assumed authorisation key using its credentials if | |
444 | * one is available. | |
445 | * | |
446 | * Return same as search_my_process_keyrings(). | |
927942aa | 447 | */ |
4bdf0bc3 | 448 | key_ref_t search_process_keyrings(struct keyring_search_context *ctx) |
927942aa DH |
449 | { |
450 | struct request_key_auth *rka; | |
451 | key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; | |
452 | ||
453 | might_sleep(); | |
454 | ||
4bdf0bc3 | 455 | key_ref = search_my_process_keyrings(ctx); |
927942aa DH |
456 | if (!IS_ERR(key_ref)) |
457 | goto found; | |
458 | err = key_ref; | |
459 | ||
b5f545c8 DH |
460 | /* if this process has an instantiation authorisation key, then we also |
461 | * search the keyrings of the process mentioned there | |
462 | * - we don't permit access to request_key auth keys via this method | |
463 | */ | |
4bdf0bc3 DH |
464 | if (ctx->cred->request_key_auth && |
465 | ctx->cred == current_cred() && | |
466 | ctx->index_key.type != &key_type_request_key_auth | |
b5f545c8 | 467 | ) { |
4bdf0bc3 DH |
468 | const struct cred *cred = ctx->cred; |
469 | ||
04c567d9 | 470 | /* defend against the auth key being revoked */ |
c69e8d9c | 471 | down_read(&cred->request_key_auth->sem); |
b5f545c8 | 472 | |
4bdf0bc3 | 473 | if (key_validate(ctx->cred->request_key_auth) == 0) { |
146aa8b1 | 474 | rka = ctx->cred->request_key_auth->payload.data[0]; |
b5f545c8 | 475 | |
4bdf0bc3 DH |
476 | ctx->cred = rka->cred; |
477 | key_ref = search_process_keyrings(ctx); | |
478 | ctx->cred = cred; | |
1da177e4 | 479 | |
c69e8d9c | 480 | up_read(&cred->request_key_auth->sem); |
04c567d9 DH |
481 | |
482 | if (!IS_ERR(key_ref)) | |
483 | goto found; | |
484 | ||
927942aa | 485 | ret = key_ref; |
04c567d9 | 486 | } else { |
c69e8d9c | 487 | up_read(&cred->request_key_auth->sem); |
3e30148c | 488 | } |
1da177e4 LT |
489 | } |
490 | ||
491 | /* no key - decide on the error we're going to go for */ | |
927942aa DH |
492 | if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY)) |
493 | key_ref = ERR_PTR(-ENOKEY); | |
494 | else if (err == ERR_PTR(-EACCES)) | |
495 | key_ref = ret; | |
496 | else | |
497 | key_ref = err; | |
1da177e4 | 498 | |
3e30148c | 499 | found: |
664cceb0 | 500 | return key_ref; |
a8b17ed0 | 501 | } |
1da177e4 | 502 | |
664cceb0 | 503 | /* |
973c9f4f | 504 | * See if the key we're looking at is the target key. |
664cceb0 | 505 | */ |
0c903ab6 DH |
506 | bool lookup_user_key_possessed(const struct key *key, |
507 | const struct key_match_data *match_data) | |
664cceb0 | 508 | { |
46291959 | 509 | return key == match_data->raw_data; |
a8b17ed0 | 510 | } |
664cceb0 | 511 | |
1da177e4 | 512 | /* |
973c9f4f DH |
513 | * Look up a key ID given us by userspace with a given permissions mask to get |
514 | * the key it refers to. | |
515 | * | |
516 | * Flags can be passed to request that special keyrings be created if referred | |
517 | * to directly, to permit partially constructed keys to be found and to skip | |
518 | * validity and permission checks on the found key. | |
519 | * | |
520 | * Returns a pointer to the key with an incremented usage count if successful; | |
521 | * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond | |
522 | * to a key or the best found key was a negative key; -EKEYREVOKED or | |
523 | * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the | |
524 | * found key doesn't grant the requested permit or the LSM denied access to it; | |
525 | * or -ENOMEM if a special keyring couldn't be created. | |
526 | * | |
527 | * In the case of a successful return, the possession attribute is set on the | |
528 | * returned key reference. | |
1da177e4 | 529 | */ |
5593122e | 530 | key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, |
8bbf4976 | 531 | key_perm_t perm) |
1da177e4 | 532 | { |
4bdf0bc3 | 533 | struct keyring_search_context ctx = { |
46291959 DH |
534 | .match_data.cmp = lookup_user_key_possessed, |
535 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
536 | .flags = KEYRING_SEARCH_NO_STATE_CHECK, | |
4bdf0bc3 | 537 | }; |
8bbf4976 | 538 | struct request_key_auth *rka; |
1da177e4 | 539 | struct key *key; |
b6dff3ec | 540 | key_ref_t key_ref, skey_ref; |
1da177e4 LT |
541 | int ret; |
542 | ||
bb952bb9 | 543 | try_again: |
4bdf0bc3 | 544 | ctx.cred = get_current_cred(); |
664cceb0 | 545 | key_ref = ERR_PTR(-ENOKEY); |
1da177e4 LT |
546 | |
547 | switch (id) { | |
548 | case KEY_SPEC_THREAD_KEYRING: | |
4bdf0bc3 | 549 | if (!ctx.cred->thread_keyring) { |
5593122e | 550 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
551 | goto error; |
552 | ||
8bbf4976 | 553 | ret = install_thread_keyring(); |
1da177e4 | 554 | if (ret < 0) { |
4d09ec0f | 555 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
556 | goto error; |
557 | } | |
bb952bb9 | 558 | goto reget_creds; |
1da177e4 LT |
559 | } |
560 | ||
4bdf0bc3 | 561 | key = ctx.cred->thread_keyring; |
ccc3e6d9 | 562 | __key_get(key); |
664cceb0 | 563 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
564 | break; |
565 | ||
566 | case KEY_SPEC_PROCESS_KEYRING: | |
4bdf0bc3 | 567 | if (!ctx.cred->process_keyring) { |
5593122e | 568 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
569 | goto error; |
570 | ||
8bbf4976 | 571 | ret = install_process_keyring(); |
1da177e4 | 572 | if (ret < 0) { |
4d09ec0f | 573 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
574 | goto error; |
575 | } | |
bb952bb9 | 576 | goto reget_creds; |
1da177e4 LT |
577 | } |
578 | ||
4bdf0bc3 | 579 | key = ctx.cred->process_keyring; |
ccc3e6d9 | 580 | __key_get(key); |
664cceb0 | 581 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
582 | break; |
583 | ||
584 | case KEY_SPEC_SESSION_KEYRING: | |
4bdf0bc3 | 585 | if (!ctx.cred->session_keyring) { |
1da177e4 LT |
586 | /* always install a session keyring upon access if one |
587 | * doesn't exist yet */ | |
8bbf4976 | 588 | ret = install_user_keyrings(); |
69664cf1 DH |
589 | if (ret < 0) |
590 | goto error; | |
3ecf1b4f DH |
591 | if (lflags & KEY_LOOKUP_CREATE) |
592 | ret = join_session_keyring(NULL); | |
593 | else | |
594 | ret = install_session_keyring( | |
4bdf0bc3 | 595 | ctx.cred->user->session_keyring); |
d84f4f99 | 596 | |
1da177e4 LT |
597 | if (ret < 0) |
598 | goto error; | |
bb952bb9 | 599 | goto reget_creds; |
4bdf0bc3 DH |
600 | } else if (ctx.cred->session_keyring == |
601 | ctx.cred->user->session_keyring && | |
3ecf1b4f DH |
602 | lflags & KEY_LOOKUP_CREATE) { |
603 | ret = join_session_keyring(NULL); | |
604 | if (ret < 0) | |
605 | goto error; | |
606 | goto reget_creds; | |
1da177e4 LT |
607 | } |
608 | ||
3e30148c | 609 | rcu_read_lock(); |
4bdf0bc3 | 610 | key = rcu_dereference(ctx.cred->session_keyring); |
ccc3e6d9 | 611 | __key_get(key); |
3e30148c | 612 | rcu_read_unlock(); |
664cceb0 | 613 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
614 | break; |
615 | ||
616 | case KEY_SPEC_USER_KEYRING: | |
4bdf0bc3 | 617 | if (!ctx.cred->user->uid_keyring) { |
8bbf4976 | 618 | ret = install_user_keyrings(); |
69664cf1 DH |
619 | if (ret < 0) |
620 | goto error; | |
621 | } | |
622 | ||
4bdf0bc3 | 623 | key = ctx.cred->user->uid_keyring; |
ccc3e6d9 | 624 | __key_get(key); |
664cceb0 | 625 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
626 | break; |
627 | ||
628 | case KEY_SPEC_USER_SESSION_KEYRING: | |
4bdf0bc3 | 629 | if (!ctx.cred->user->session_keyring) { |
8bbf4976 | 630 | ret = install_user_keyrings(); |
69664cf1 DH |
631 | if (ret < 0) |
632 | goto error; | |
633 | } | |
634 | ||
4bdf0bc3 | 635 | key = ctx.cred->user->session_keyring; |
ccc3e6d9 | 636 | __key_get(key); |
664cceb0 | 637 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
638 | break; |
639 | ||
640 | case KEY_SPEC_GROUP_KEYRING: | |
641 | /* group keyrings are not yet supported */ | |
4d09ec0f | 642 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
643 | goto error; |
644 | ||
b5f545c8 | 645 | case KEY_SPEC_REQKEY_AUTH_KEY: |
4bdf0bc3 | 646 | key = ctx.cred->request_key_auth; |
b5f545c8 DH |
647 | if (!key) |
648 | goto error; | |
649 | ||
ccc3e6d9 | 650 | __key_get(key); |
b5f545c8 DH |
651 | key_ref = make_key_ref(key, 1); |
652 | break; | |
653 | ||
8bbf4976 | 654 | case KEY_SPEC_REQUESTOR_KEYRING: |
4bdf0bc3 | 655 | if (!ctx.cred->request_key_auth) |
8bbf4976 DH |
656 | goto error; |
657 | ||
4bdf0bc3 | 658 | down_read(&ctx.cred->request_key_auth->sem); |
f67dabbd | 659 | if (test_bit(KEY_FLAG_REVOKED, |
4bdf0bc3 | 660 | &ctx.cred->request_key_auth->flags)) { |
8bbf4976 DH |
661 | key_ref = ERR_PTR(-EKEYREVOKED); |
662 | key = NULL; | |
663 | } else { | |
146aa8b1 | 664 | rka = ctx.cred->request_key_auth->payload.data[0]; |
8bbf4976 | 665 | key = rka->dest_keyring; |
ccc3e6d9 | 666 | __key_get(key); |
8bbf4976 | 667 | } |
4bdf0bc3 | 668 | up_read(&ctx.cred->request_key_auth->sem); |
8bbf4976 DH |
669 | if (!key) |
670 | goto error; | |
671 | key_ref = make_key_ref(key, 1); | |
672 | break; | |
673 | ||
1da177e4 | 674 | default: |
664cceb0 | 675 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
676 | if (id < 1) |
677 | goto error; | |
678 | ||
679 | key = key_lookup(id); | |
664cceb0 | 680 | if (IS_ERR(key)) { |
e231c2ee | 681 | key_ref = ERR_CAST(key); |
1da177e4 | 682 | goto error; |
664cceb0 DH |
683 | } |
684 | ||
685 | key_ref = make_key_ref(key, 0); | |
686 | ||
687 | /* check to see if we possess the key */ | |
4bdf0bc3 DH |
688 | ctx.index_key.type = key->type; |
689 | ctx.index_key.description = key->description; | |
690 | ctx.index_key.desc_len = strlen(key->description); | |
46291959 | 691 | ctx.match_data.raw_data = key; |
4bdf0bc3 DH |
692 | kdebug("check possessed"); |
693 | skey_ref = search_process_keyrings(&ctx); | |
694 | kdebug("possessed=%p", skey_ref); | |
664cceb0 DH |
695 | |
696 | if (!IS_ERR(skey_ref)) { | |
697 | key_put(key); | |
698 | key_ref = skey_ref; | |
699 | } | |
700 | ||
1da177e4 LT |
701 | break; |
702 | } | |
703 | ||
5593122e DH |
704 | /* unlink does not use the nominated key in any way, so can skip all |
705 | * the permission checks as it is only concerned with the keyring */ | |
706 | if (lflags & KEY_LOOKUP_FOR_UNLINK) { | |
707 | ret = 0; | |
708 | goto error; | |
709 | } | |
710 | ||
711 | if (!(lflags & KEY_LOOKUP_PARTIAL)) { | |
76181c13 DH |
712 | ret = wait_for_key_construction(key, true); |
713 | switch (ret) { | |
714 | case -ERESTARTSYS: | |
715 | goto invalid_key; | |
716 | default: | |
717 | if (perm) | |
718 | goto invalid_key; | |
719 | case 0: | |
720 | break; | |
721 | } | |
722 | } else if (perm) { | |
1da177e4 LT |
723 | ret = key_validate(key); |
724 | if (ret < 0) | |
725 | goto invalid_key; | |
726 | } | |
727 | ||
728 | ret = -EIO; | |
5593122e DH |
729 | if (!(lflags & KEY_LOOKUP_PARTIAL) && |
730 | !test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) | |
1da177e4 LT |
731 | goto invalid_key; |
732 | ||
3e30148c | 733 | /* check the permissions */ |
4bdf0bc3 | 734 | ret = key_task_permission(key_ref, ctx.cred, perm); |
29db9190 | 735 | if (ret < 0) |
1da177e4 LT |
736 | goto invalid_key; |
737 | ||
31d5a79d DH |
738 | key->last_used_at = current_kernel_time().tv_sec; |
739 | ||
664cceb0 | 740 | error: |
4bdf0bc3 | 741 | put_cred(ctx.cred); |
664cceb0 | 742 | return key_ref; |
1da177e4 | 743 | |
664cceb0 DH |
744 | invalid_key: |
745 | key_ref_put(key_ref); | |
746 | key_ref = ERR_PTR(ret); | |
1da177e4 LT |
747 | goto error; |
748 | ||
bb952bb9 DH |
749 | /* if we attempted to install a keyring, then it may have caused new |
750 | * creds to be installed */ | |
751 | reget_creds: | |
4bdf0bc3 | 752 | put_cred(ctx.cred); |
bb952bb9 | 753 | goto try_again; |
a8b17ed0 | 754 | } |
bb952bb9 | 755 | |
1da177e4 | 756 | /* |
973c9f4f DH |
757 | * Join the named keyring as the session keyring if possible else attempt to |
758 | * create a new one of that name and join that. | |
759 | * | |
760 | * If the name is NULL, an empty anonymous keyring will be installed as the | |
761 | * session keyring. | |
762 | * | |
763 | * Named session keyrings are joined with a semaphore held to prevent the | |
764 | * keyrings from going away whilst the attempt is made to going them and also | |
765 | * to prevent a race in creating compatible session keyrings. | |
1da177e4 LT |
766 | */ |
767 | long join_session_keyring(const char *name) | |
768 | { | |
d84f4f99 DH |
769 | const struct cred *old; |
770 | struct cred *new; | |
1da177e4 | 771 | struct key *keyring; |
d84f4f99 DH |
772 | long ret, serial; |
773 | ||
d84f4f99 DH |
774 | new = prepare_creds(); |
775 | if (!new) | |
776 | return -ENOMEM; | |
777 | old = current_cred(); | |
1da177e4 LT |
778 | |
779 | /* if no name is provided, install an anonymous keyring */ | |
780 | if (!name) { | |
d84f4f99 | 781 | ret = install_session_keyring_to_cred(new, NULL); |
1da177e4 LT |
782 | if (ret < 0) |
783 | goto error; | |
784 | ||
3a50597d | 785 | serial = new->session_keyring->serial; |
d84f4f99 DH |
786 | ret = commit_creds(new); |
787 | if (ret == 0) | |
788 | ret = serial; | |
789 | goto okay; | |
1da177e4 LT |
790 | } |
791 | ||
792 | /* allow the user to join or create a named keyring */ | |
bb003079 | 793 | mutex_lock(&key_session_mutex); |
1da177e4 LT |
794 | |
795 | /* look for an existing keyring of this name */ | |
69664cf1 | 796 | keyring = find_keyring_by_name(name, false); |
1da177e4 LT |
797 | if (PTR_ERR(keyring) == -ENOKEY) { |
798 | /* not found - try and create a new one */ | |
96b5c8fe DH |
799 | keyring = keyring_alloc( |
800 | name, old->uid, old->gid, old, | |
801 | KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK, | |
5ac7eace | 802 | KEY_ALLOC_IN_QUOTA, NULL, NULL); |
1da177e4 LT |
803 | if (IS_ERR(keyring)) { |
804 | ret = PTR_ERR(keyring); | |
bcf945d3 | 805 | goto error2; |
1da177e4 | 806 | } |
d84f4f99 | 807 | } else if (IS_ERR(keyring)) { |
1da177e4 LT |
808 | ret = PTR_ERR(keyring); |
809 | goto error2; | |
3a50597d | 810 | } else if (keyring == new->session_keyring) { |
23567fd0 | 811 | key_put(keyring); |
3a50597d DH |
812 | ret = 0; |
813 | goto error2; | |
1da177e4 LT |
814 | } |
815 | ||
816 | /* we've got a keyring - now to install it */ | |
d84f4f99 | 817 | ret = install_session_keyring_to_cred(new, keyring); |
1da177e4 LT |
818 | if (ret < 0) |
819 | goto error2; | |
820 | ||
d84f4f99 DH |
821 | commit_creds(new); |
822 | mutex_unlock(&key_session_mutex); | |
823 | ||
1da177e4 LT |
824 | ret = keyring->serial; |
825 | key_put(keyring); | |
d84f4f99 DH |
826 | okay: |
827 | return ret; | |
1da177e4 | 828 | |
664cceb0 | 829 | error2: |
bb003079 | 830 | mutex_unlock(&key_session_mutex); |
664cceb0 | 831 | error: |
d84f4f99 | 832 | abort_creds(new); |
1da177e4 | 833 | return ret; |
d84f4f99 | 834 | } |
ee18d64c DH |
835 | |
836 | /* | |
973c9f4f DH |
837 | * Replace a process's session keyring on behalf of one of its children when |
838 | * the target process is about to resume userspace execution. | |
ee18d64c | 839 | */ |
67d12145 | 840 | void key_change_session_keyring(struct callback_head *twork) |
ee18d64c | 841 | { |
413cd3d9 | 842 | const struct cred *old = current_cred(); |
67d12145 | 843 | struct cred *new = container_of(twork, struct cred, rcu); |
ee18d64c | 844 | |
413cd3d9 ON |
845 | if (unlikely(current->flags & PF_EXITING)) { |
846 | put_cred(new); | |
ee18d64c | 847 | return; |
413cd3d9 | 848 | } |
ee18d64c | 849 | |
ee18d64c DH |
850 | new-> uid = old-> uid; |
851 | new-> euid = old-> euid; | |
852 | new-> suid = old-> suid; | |
853 | new->fsuid = old->fsuid; | |
854 | new-> gid = old-> gid; | |
855 | new-> egid = old-> egid; | |
856 | new-> sgid = old-> sgid; | |
857 | new->fsgid = old->fsgid; | |
858 | new->user = get_uid(old->user); | |
ba0e3427 | 859 | new->user_ns = get_user_ns(old->user_ns); |
ee18d64c DH |
860 | new->group_info = get_group_info(old->group_info); |
861 | ||
862 | new->securebits = old->securebits; | |
863 | new->cap_inheritable = old->cap_inheritable; | |
864 | new->cap_permitted = old->cap_permitted; | |
865 | new->cap_effective = old->cap_effective; | |
58319057 | 866 | new->cap_ambient = old->cap_ambient; |
ee18d64c DH |
867 | new->cap_bset = old->cap_bset; |
868 | ||
869 | new->jit_keyring = old->jit_keyring; | |
870 | new->thread_keyring = key_get(old->thread_keyring); | |
3a50597d | 871 | new->process_keyring = key_get(old->process_keyring); |
ee18d64c DH |
872 | |
873 | security_transfer_creds(new, old); | |
874 | ||
875 | commit_creds(new); | |
876 | } | |
c124bde2 MZ |
877 | |
878 | /* | |
879 | * Make sure that root's user and user-session keyrings exist. | |
880 | */ | |
881 | static int __init init_root_keyring(void) | |
882 | { | |
883 | return install_user_keyrings(); | |
884 | } | |
885 | ||
886 | late_initcall(init_root_keyring); |