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 | ||
1da177e4 LT |
12 | #include <linux/init.h> |
13 | #include <linux/sched.h> | |
8703e8a4 | 14 | #include <linux/sched/user.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 | 31 | struct key_user root_key_user = { |
ddb99e11 | 32 | .usage = REFCOUNT_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, |
237bbd29 EB |
79 | KEY_ALLOC_UID_KEYRING | |
80 | KEY_ALLOC_IN_QUOTA, | |
5ac7eace | 81 | NULL, NULL); |
69664cf1 DH |
82 | if (IS_ERR(uid_keyring)) { |
83 | ret = PTR_ERR(uid_keyring); | |
84 | goto error; | |
85 | } | |
86 | } | |
87 | ||
88 | /* get a default session keyring (which might also exist | |
89 | * already) */ | |
9a56c2db | 90 | sprintf(buf, "_uid_ses.%u", uid); |
69664cf1 DH |
91 | |
92 | session_keyring = find_keyring_by_name(buf, true); | |
93 | if (IS_ERR(session_keyring)) { | |
94 | session_keyring = | |
9a56c2db | 95 | keyring_alloc(buf, user->uid, INVALID_GID, |
96b5c8fe | 96 | cred, user_keyring_perm, |
237bbd29 EB |
97 | KEY_ALLOC_UID_KEYRING | |
98 | KEY_ALLOC_IN_QUOTA, | |
5ac7eace | 99 | NULL, NULL); |
69664cf1 DH |
100 | if (IS_ERR(session_keyring)) { |
101 | ret = PTR_ERR(session_keyring); | |
102 | goto error_release; | |
103 | } | |
104 | ||
105 | /* we install a link from the user session keyring to | |
106 | * the user keyring */ | |
107 | ret = key_link(session_keyring, uid_keyring); | |
108 | if (ret < 0) | |
109 | goto error_release_both; | |
110 | } | |
111 | ||
112 | /* install the keyrings */ | |
113 | user->uid_keyring = uid_keyring; | |
114 | user->session_keyring = session_keyring; | |
1da177e4 LT |
115 | } |
116 | ||
69664cf1 DH |
117 | mutex_unlock(&key_user_keyring_mutex); |
118 | kleave(" = 0"); | |
119 | return 0; | |
1da177e4 | 120 | |
69664cf1 DH |
121 | error_release_both: |
122 | key_put(session_keyring); | |
123 | error_release: | |
124 | key_put(uid_keyring); | |
664cceb0 | 125 | error: |
69664cf1 DH |
126 | mutex_unlock(&key_user_keyring_mutex); |
127 | kleave(" = %d", ret); | |
1da177e4 | 128 | return ret; |
69664cf1 | 129 | } |
1da177e4 | 130 | |
1da177e4 | 131 | /* |
c9f838d1 EB |
132 | * Install a thread keyring to the given credentials struct if it didn't have |
133 | * one already. This is allowed to overrun the quota. | |
134 | * | |
135 | * Return: 0 if a thread keyring is now present; -errno on failure. | |
1da177e4 | 136 | */ |
d84f4f99 | 137 | int install_thread_keyring_to_cred(struct cred *new) |
1da177e4 | 138 | { |
d84f4f99 | 139 | struct key *keyring; |
1da177e4 | 140 | |
c9f838d1 EB |
141 | if (new->thread_keyring) |
142 | return 0; | |
143 | ||
d84f4f99 | 144 | keyring = keyring_alloc("_tid", new->uid, new->gid, new, |
96b5c8fe | 145 | KEY_POS_ALL | KEY_USR_VIEW, |
5ac7eace DH |
146 | KEY_ALLOC_QUOTA_OVERRUN, |
147 | NULL, NULL); | |
d84f4f99 DH |
148 | if (IS_ERR(keyring)) |
149 | return PTR_ERR(keyring); | |
1da177e4 | 150 | |
d84f4f99 DH |
151 | new->thread_keyring = keyring; |
152 | return 0; | |
153 | } | |
1da177e4 | 154 | |
1da177e4 | 155 | /* |
c9f838d1 EB |
156 | * Install a thread keyring to the current task if it didn't have one already. |
157 | * | |
158 | * Return: 0 if a thread keyring is now present; -errno on failure. | |
1da177e4 | 159 | */ |
d84f4f99 | 160 | static int install_thread_keyring(void) |
1da177e4 | 161 | { |
d84f4f99 | 162 | struct cred *new; |
1da177e4 LT |
163 | int ret; |
164 | ||
d84f4f99 DH |
165 | new = prepare_creds(); |
166 | if (!new) | |
167 | return -ENOMEM; | |
1da177e4 | 168 | |
d84f4f99 DH |
169 | ret = install_thread_keyring_to_cred(new); |
170 | if (ret < 0) { | |
171 | abort_creds(new); | |
172 | return ret; | |
1da177e4 LT |
173 | } |
174 | ||
d84f4f99 DH |
175 | return commit_creds(new); |
176 | } | |
1da177e4 | 177 | |
d84f4f99 | 178 | /* |
c9f838d1 EB |
179 | * Install a process keyring to the given credentials struct if it didn't have |
180 | * one already. This is allowed to overrun the quota. | |
973c9f4f | 181 | * |
c9f838d1 | 182 | * Return: 0 if a process keyring is now present; -errno on failure. |
d84f4f99 DH |
183 | */ |
184 | int install_process_keyring_to_cred(struct cred *new) | |
185 | { | |
186 | struct key *keyring; | |
1da177e4 | 187 | |
3a50597d | 188 | if (new->process_keyring) |
c9f838d1 | 189 | return 0; |
d84f4f99 | 190 | |
96b5c8fe DH |
191 | keyring = keyring_alloc("_pid", new->uid, new->gid, new, |
192 | KEY_POS_ALL | KEY_USR_VIEW, | |
5ac7eace DH |
193 | KEY_ALLOC_QUOTA_OVERRUN, |
194 | NULL, NULL); | |
d84f4f99 DH |
195 | if (IS_ERR(keyring)) |
196 | return PTR_ERR(keyring); | |
197 | ||
3a50597d DH |
198 | new->process_keyring = keyring; |
199 | return 0; | |
d84f4f99 | 200 | } |
1da177e4 | 201 | |
1da177e4 | 202 | /* |
c9f838d1 | 203 | * Install a process keyring to the current task if it didn't have one already. |
973c9f4f | 204 | * |
c9f838d1 | 205 | * Return: 0 if a process keyring is now present; -errno on failure. |
1da177e4 | 206 | */ |
d84f4f99 | 207 | static int install_process_keyring(void) |
1da177e4 | 208 | { |
d84f4f99 | 209 | struct cred *new; |
1da177e4 LT |
210 | int ret; |
211 | ||
d84f4f99 DH |
212 | new = prepare_creds(); |
213 | if (!new) | |
214 | return -ENOMEM; | |
1da177e4 | 215 | |
d84f4f99 DH |
216 | ret = install_process_keyring_to_cred(new); |
217 | if (ret < 0) { | |
218 | abort_creds(new); | |
c9f838d1 | 219 | return ret; |
1da177e4 LT |
220 | } |
221 | ||
d84f4f99 DH |
222 | return commit_creds(new); |
223 | } | |
1da177e4 | 224 | |
1da177e4 | 225 | /* |
c9f838d1 EB |
226 | * Install the given keyring as the session keyring of the given credentials |
227 | * struct, replacing the existing one if any. If the given keyring is NULL, | |
228 | * then install a new anonymous session keyring. | |
229 | * | |
230 | * Return: 0 on success; -errno on failure. | |
1da177e4 | 231 | */ |
685bfd2c | 232 | int install_session_keyring_to_cred(struct cred *cred, struct key *keyring) |
1da177e4 | 233 | { |
7e047ef5 | 234 | unsigned long flags; |
1da177e4 | 235 | struct key *old; |
1a26feb9 DH |
236 | |
237 | might_sleep(); | |
1da177e4 LT |
238 | |
239 | /* create an empty session keyring */ | |
240 | if (!keyring) { | |
7e047ef5 | 241 | flags = KEY_ALLOC_QUOTA_OVERRUN; |
3a50597d | 242 | if (cred->session_keyring) |
7e047ef5 DH |
243 | flags = KEY_ALLOC_IN_QUOTA; |
244 | ||
96b5c8fe DH |
245 | keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred, |
246 | KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ, | |
5ac7eace | 247 | flags, NULL, NULL); |
1a26feb9 DH |
248 | if (IS_ERR(keyring)) |
249 | return PTR_ERR(keyring); | |
d84f4f99 | 250 | } else { |
ccc3e6d9 | 251 | __key_get(keyring); |
1da177e4 LT |
252 | } |
253 | ||
254 | /* install the keyring */ | |
3a50597d DH |
255 | old = cred->session_keyring; |
256 | rcu_assign_pointer(cred->session_keyring, keyring); | |
257 | ||
258 | if (old) | |
1a26feb9 | 259 | key_put(old); |
1da177e4 | 260 | |
1a26feb9 | 261 | return 0; |
d84f4f99 | 262 | } |
1da177e4 | 263 | |
1da177e4 | 264 | /* |
c9f838d1 EB |
265 | * Install the given keyring as the session keyring of the current task, |
266 | * replacing the existing one if any. If the given keyring is NULL, then | |
267 | * install a new anonymous session keyring. | |
268 | * | |
269 | * Return: 0 on success; -errno on failure. | |
1da177e4 | 270 | */ |
d84f4f99 | 271 | static int install_session_keyring(struct key *keyring) |
1da177e4 | 272 | { |
d84f4f99 DH |
273 | struct cred *new; |
274 | int ret; | |
1da177e4 | 275 | |
d84f4f99 DH |
276 | new = prepare_creds(); |
277 | if (!new) | |
278 | return -ENOMEM; | |
1da177e4 | 279 | |
99599537 | 280 | ret = install_session_keyring_to_cred(new, keyring); |
d84f4f99 DH |
281 | if (ret < 0) { |
282 | abort_creds(new); | |
283 | return ret; | |
284 | } | |
1da177e4 | 285 | |
d84f4f99 DH |
286 | return commit_creds(new); |
287 | } | |
1da177e4 | 288 | |
1da177e4 | 289 | /* |
973c9f4f | 290 | * Handle the fsuid changing. |
1da177e4 LT |
291 | */ |
292 | void key_fsuid_changed(struct task_struct *tsk) | |
293 | { | |
294 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
295 | BUG_ON(!tsk->cred); |
296 | if (tsk->cred->thread_keyring) { | |
297 | down_write(&tsk->cred->thread_keyring->sem); | |
298 | tsk->cred->thread_keyring->uid = tsk->cred->fsuid; | |
299 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 300 | } |
a8b17ed0 | 301 | } |
1da177e4 | 302 | |
1da177e4 | 303 | /* |
973c9f4f | 304 | * Handle the fsgid changing. |
1da177e4 LT |
305 | */ |
306 | void key_fsgid_changed(struct task_struct *tsk) | |
307 | { | |
308 | /* update the ownership of the thread keyring */ | |
b6dff3ec DH |
309 | BUG_ON(!tsk->cred); |
310 | if (tsk->cred->thread_keyring) { | |
311 | down_write(&tsk->cred->thread_keyring->sem); | |
312 | tsk->cred->thread_keyring->gid = tsk->cred->fsgid; | |
313 | up_write(&tsk->cred->thread_keyring->sem); | |
1da177e4 | 314 | } |
a8b17ed0 | 315 | } |
1da177e4 | 316 | |
1da177e4 | 317 | /* |
973c9f4f DH |
318 | * Search the process keyrings attached to the supplied cred for the first |
319 | * matching key. | |
320 | * | |
321 | * The search criteria are the type and the match function. The description is | |
322 | * given to the match function as a parameter, but doesn't otherwise influence | |
323 | * the search. Typically the match function will compare the description | |
324 | * parameter to the key's description. | |
325 | * | |
326 | * This can only search keyrings that grant Search permission to the supplied | |
327 | * credentials. Keyrings linked to searched keyrings will also be searched if | |
328 | * they grant Search permission too. Keys can only be found if they grant | |
329 | * Search permission to the credentials. | |
330 | * | |
331 | * Returns a pointer to the key with the key usage count incremented if | |
332 | * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only | |
333 | * matched negative keys. | |
334 | * | |
335 | * In the case of a successful return, the possession attribute is set on the | |
336 | * returned key reference. | |
1da177e4 | 337 | */ |
4bdf0bc3 | 338 | key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx) |
1da177e4 | 339 | { |
b5f545c8 | 340 | key_ref_t key_ref, ret, err; |
1da177e4 LT |
341 | |
342 | /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were | |
343 | * searchable, but we failed to find a key or we found a negative key; | |
344 | * otherwise we want to return a sample error (probably -EACCES) if | |
345 | * none of the keyrings were searchable | |
346 | * | |
347 | * in terms of priority: success > -ENOKEY > -EAGAIN > other error | |
348 | */ | |
664cceb0 | 349 | key_ref = NULL; |
1da177e4 LT |
350 | ret = NULL; |
351 | err = ERR_PTR(-EAGAIN); | |
352 | ||
353 | /* search the thread keyring first */ | |
4bdf0bc3 | 354 | if (ctx->cred->thread_keyring) { |
664cceb0 | 355 | key_ref = keyring_search_aux( |
4bdf0bc3 | 356 | make_key_ref(ctx->cred->thread_keyring, 1), ctx); |
664cceb0 | 357 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
358 | goto found; |
359 | ||
664cceb0 | 360 | switch (PTR_ERR(key_ref)) { |
1da177e4 | 361 | case -EAGAIN: /* no key */ |
1da177e4 | 362 | case -ENOKEY: /* negative key */ |
664cceb0 | 363 | ret = key_ref; |
1da177e4 LT |
364 | break; |
365 | default: | |
664cceb0 | 366 | err = key_ref; |
1da177e4 LT |
367 | break; |
368 | } | |
369 | } | |
370 | ||
371 | /* search the process keyring second */ | |
4bdf0bc3 | 372 | if (ctx->cred->process_keyring) { |
664cceb0 | 373 | key_ref = keyring_search_aux( |
4bdf0bc3 | 374 | make_key_ref(ctx->cred->process_keyring, 1), ctx); |
664cceb0 | 375 | if (!IS_ERR(key_ref)) |
1da177e4 LT |
376 | goto found; |
377 | ||
664cceb0 | 378 | switch (PTR_ERR(key_ref)) { |
1da177e4 | 379 | case -EAGAIN: /* no key */ |
fe9453a1 DH |
380 | if (ret) |
381 | break; | |
1da177e4 | 382 | case -ENOKEY: /* negative key */ |
664cceb0 | 383 | ret = key_ref; |
1da177e4 LT |
384 | break; |
385 | default: | |
664cceb0 | 386 | err = key_ref; |
1da177e4 LT |
387 | break; |
388 | } | |
389 | } | |
390 | ||
3e30148c | 391 | /* search the session keyring */ |
4bdf0bc3 | 392 | if (ctx->cred->session_keyring) { |
8589b4e0 | 393 | rcu_read_lock(); |
664cceb0 | 394 | key_ref = keyring_search_aux( |
4bdf0bc3 DH |
395 | make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1), |
396 | ctx); | |
8589b4e0 | 397 | rcu_read_unlock(); |
3e30148c | 398 | |
664cceb0 | 399 | if (!IS_ERR(key_ref)) |
3e30148c DH |
400 | goto found; |
401 | ||
664cceb0 | 402 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
403 | case -EAGAIN: /* no key */ |
404 | if (ret) | |
405 | break; | |
406 | case -ENOKEY: /* negative key */ | |
664cceb0 | 407 | ret = key_ref; |
3e30148c DH |
408 | break; |
409 | default: | |
664cceb0 | 410 | err = key_ref; |
3e30148c DH |
411 | break; |
412 | } | |
b5f545c8 DH |
413 | } |
414 | /* or search the user-session keyring */ | |
4bdf0bc3 | 415 | else if (ctx->cred->user->session_keyring) { |
b5f545c8 | 416 | key_ref = keyring_search_aux( |
4bdf0bc3 DH |
417 | make_key_ref(ctx->cred->user->session_keyring, 1), |
418 | ctx); | |
664cceb0 | 419 | if (!IS_ERR(key_ref)) |
3e30148c DH |
420 | goto found; |
421 | ||
664cceb0 | 422 | switch (PTR_ERR(key_ref)) { |
3e30148c DH |
423 | case -EAGAIN: /* no key */ |
424 | if (ret) | |
425 | break; | |
426 | case -ENOKEY: /* negative key */ | |
664cceb0 | 427 | ret = key_ref; |
3e30148c DH |
428 | break; |
429 | default: | |
664cceb0 | 430 | err = key_ref; |
3e30148c DH |
431 | break; |
432 | } | |
8589b4e0 | 433 | } |
b5f545c8 | 434 | |
927942aa DH |
435 | /* no key - decide on the error we're going to go for */ |
436 | key_ref = ret ? ret : err; | |
437 | ||
438 | found: | |
439 | return key_ref; | |
440 | } | |
441 | ||
927942aa | 442 | /* |
973c9f4f DH |
443 | * Search the process keyrings attached to the supplied cred for the first |
444 | * matching key in the manner of search_my_process_keyrings(), but also search | |
445 | * the keys attached to the assumed authorisation key using its credentials if | |
446 | * one is available. | |
447 | * | |
448 | * Return same as search_my_process_keyrings(). | |
927942aa | 449 | */ |
4bdf0bc3 | 450 | key_ref_t search_process_keyrings(struct keyring_search_context *ctx) |
927942aa DH |
451 | { |
452 | struct request_key_auth *rka; | |
453 | key_ref_t key_ref, ret = ERR_PTR(-EACCES), err; | |
454 | ||
455 | might_sleep(); | |
456 | ||
4bdf0bc3 | 457 | key_ref = search_my_process_keyrings(ctx); |
927942aa DH |
458 | if (!IS_ERR(key_ref)) |
459 | goto found; | |
460 | err = key_ref; | |
461 | ||
b5f545c8 DH |
462 | /* if this process has an instantiation authorisation key, then we also |
463 | * search the keyrings of the process mentioned there | |
464 | * - we don't permit access to request_key auth keys via this method | |
465 | */ | |
4bdf0bc3 DH |
466 | if (ctx->cred->request_key_auth && |
467 | ctx->cred == current_cred() && | |
468 | ctx->index_key.type != &key_type_request_key_auth | |
b5f545c8 | 469 | ) { |
4bdf0bc3 DH |
470 | const struct cred *cred = ctx->cred; |
471 | ||
04c567d9 | 472 | /* defend against the auth key being revoked */ |
c69e8d9c | 473 | down_read(&cred->request_key_auth->sem); |
b5f545c8 | 474 | |
4bdf0bc3 | 475 | if (key_validate(ctx->cred->request_key_auth) == 0) { |
146aa8b1 | 476 | rka = ctx->cred->request_key_auth->payload.data[0]; |
b5f545c8 | 477 | |
4bdf0bc3 DH |
478 | ctx->cred = rka->cred; |
479 | key_ref = search_process_keyrings(ctx); | |
480 | ctx->cred = cred; | |
1da177e4 | 481 | |
c69e8d9c | 482 | up_read(&cred->request_key_auth->sem); |
04c567d9 DH |
483 | |
484 | if (!IS_ERR(key_ref)) | |
485 | goto found; | |
486 | ||
927942aa | 487 | ret = key_ref; |
04c567d9 | 488 | } else { |
c69e8d9c | 489 | up_read(&cred->request_key_auth->sem); |
3e30148c | 490 | } |
1da177e4 LT |
491 | } |
492 | ||
493 | /* no key - decide on the error we're going to go for */ | |
927942aa DH |
494 | if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY)) |
495 | key_ref = ERR_PTR(-ENOKEY); | |
496 | else if (err == ERR_PTR(-EACCES)) | |
497 | key_ref = ret; | |
498 | else | |
499 | key_ref = err; | |
1da177e4 | 500 | |
3e30148c | 501 | found: |
664cceb0 | 502 | return key_ref; |
a8b17ed0 | 503 | } |
1da177e4 | 504 | |
664cceb0 | 505 | /* |
973c9f4f | 506 | * See if the key we're looking at is the target key. |
664cceb0 | 507 | */ |
0c903ab6 DH |
508 | bool lookup_user_key_possessed(const struct key *key, |
509 | const struct key_match_data *match_data) | |
664cceb0 | 510 | { |
46291959 | 511 | return key == match_data->raw_data; |
a8b17ed0 | 512 | } |
664cceb0 | 513 | |
1da177e4 | 514 | /* |
973c9f4f DH |
515 | * Look up a key ID given us by userspace with a given permissions mask to get |
516 | * the key it refers to. | |
517 | * | |
518 | * Flags can be passed to request that special keyrings be created if referred | |
519 | * to directly, to permit partially constructed keys to be found and to skip | |
520 | * validity and permission checks on the found key. | |
521 | * | |
522 | * Returns a pointer to the key with an incremented usage count if successful; | |
523 | * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond | |
524 | * to a key or the best found key was a negative key; -EKEYREVOKED or | |
525 | * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the | |
526 | * found key doesn't grant the requested permit or the LSM denied access to it; | |
527 | * or -ENOMEM if a special keyring couldn't be created. | |
528 | * | |
529 | * In the case of a successful return, the possession attribute is set on the | |
530 | * returned key reference. | |
1da177e4 | 531 | */ |
5593122e | 532 | key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags, |
8bbf4976 | 533 | key_perm_t perm) |
1da177e4 | 534 | { |
4bdf0bc3 | 535 | struct keyring_search_context ctx = { |
46291959 DH |
536 | .match_data.cmp = lookup_user_key_possessed, |
537 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
538 | .flags = KEYRING_SEARCH_NO_STATE_CHECK, | |
4bdf0bc3 | 539 | }; |
8bbf4976 | 540 | struct request_key_auth *rka; |
1da177e4 | 541 | struct key *key; |
b6dff3ec | 542 | key_ref_t key_ref, skey_ref; |
1da177e4 LT |
543 | int ret; |
544 | ||
bb952bb9 | 545 | try_again: |
4bdf0bc3 | 546 | ctx.cred = get_current_cred(); |
664cceb0 | 547 | key_ref = ERR_PTR(-ENOKEY); |
1da177e4 LT |
548 | |
549 | switch (id) { | |
550 | case KEY_SPEC_THREAD_KEYRING: | |
4bdf0bc3 | 551 | if (!ctx.cred->thread_keyring) { |
5593122e | 552 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
553 | goto error; |
554 | ||
8bbf4976 | 555 | ret = install_thread_keyring(); |
1da177e4 | 556 | if (ret < 0) { |
4d09ec0f | 557 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
558 | goto error; |
559 | } | |
bb952bb9 | 560 | goto reget_creds; |
1da177e4 LT |
561 | } |
562 | ||
4bdf0bc3 | 563 | key = ctx.cred->thread_keyring; |
ccc3e6d9 | 564 | __key_get(key); |
664cceb0 | 565 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
566 | break; |
567 | ||
568 | case KEY_SPEC_PROCESS_KEYRING: | |
4bdf0bc3 | 569 | if (!ctx.cred->process_keyring) { |
5593122e | 570 | if (!(lflags & KEY_LOOKUP_CREATE)) |
1da177e4 LT |
571 | goto error; |
572 | ||
8bbf4976 | 573 | ret = install_process_keyring(); |
1da177e4 | 574 | if (ret < 0) { |
4d09ec0f | 575 | key_ref = ERR_PTR(ret); |
1da177e4 LT |
576 | goto error; |
577 | } | |
bb952bb9 | 578 | goto reget_creds; |
1da177e4 LT |
579 | } |
580 | ||
4bdf0bc3 | 581 | key = ctx.cred->process_keyring; |
ccc3e6d9 | 582 | __key_get(key); |
664cceb0 | 583 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
584 | break; |
585 | ||
586 | case KEY_SPEC_SESSION_KEYRING: | |
4bdf0bc3 | 587 | if (!ctx.cred->session_keyring) { |
1da177e4 LT |
588 | /* always install a session keyring upon access if one |
589 | * doesn't exist yet */ | |
8bbf4976 | 590 | ret = install_user_keyrings(); |
69664cf1 DH |
591 | if (ret < 0) |
592 | goto error; | |
3ecf1b4f DH |
593 | if (lflags & KEY_LOOKUP_CREATE) |
594 | ret = join_session_keyring(NULL); | |
595 | else | |
596 | ret = install_session_keyring( | |
4bdf0bc3 | 597 | ctx.cred->user->session_keyring); |
d84f4f99 | 598 | |
1da177e4 LT |
599 | if (ret < 0) |
600 | goto error; | |
bb952bb9 | 601 | goto reget_creds; |
4bdf0bc3 DH |
602 | } else if (ctx.cred->session_keyring == |
603 | ctx.cred->user->session_keyring && | |
3ecf1b4f DH |
604 | lflags & KEY_LOOKUP_CREATE) { |
605 | ret = join_session_keyring(NULL); | |
606 | if (ret < 0) | |
607 | goto error; | |
608 | goto reget_creds; | |
1da177e4 LT |
609 | } |
610 | ||
3e30148c | 611 | rcu_read_lock(); |
4bdf0bc3 | 612 | key = rcu_dereference(ctx.cred->session_keyring); |
ccc3e6d9 | 613 | __key_get(key); |
3e30148c | 614 | rcu_read_unlock(); |
664cceb0 | 615 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
616 | break; |
617 | ||
618 | case KEY_SPEC_USER_KEYRING: | |
4bdf0bc3 | 619 | if (!ctx.cred->user->uid_keyring) { |
8bbf4976 | 620 | ret = install_user_keyrings(); |
69664cf1 DH |
621 | if (ret < 0) |
622 | goto error; | |
623 | } | |
624 | ||
4bdf0bc3 | 625 | key = ctx.cred->user->uid_keyring; |
ccc3e6d9 | 626 | __key_get(key); |
664cceb0 | 627 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
628 | break; |
629 | ||
630 | case KEY_SPEC_USER_SESSION_KEYRING: | |
4bdf0bc3 | 631 | if (!ctx.cred->user->session_keyring) { |
8bbf4976 | 632 | ret = install_user_keyrings(); |
69664cf1 DH |
633 | if (ret < 0) |
634 | goto error; | |
635 | } | |
636 | ||
4bdf0bc3 | 637 | key = ctx.cred->user->session_keyring; |
ccc3e6d9 | 638 | __key_get(key); |
664cceb0 | 639 | key_ref = make_key_ref(key, 1); |
1da177e4 LT |
640 | break; |
641 | ||
642 | case KEY_SPEC_GROUP_KEYRING: | |
643 | /* group keyrings are not yet supported */ | |
4d09ec0f | 644 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
645 | goto error; |
646 | ||
b5f545c8 | 647 | case KEY_SPEC_REQKEY_AUTH_KEY: |
4bdf0bc3 | 648 | key = ctx.cred->request_key_auth; |
b5f545c8 DH |
649 | if (!key) |
650 | goto error; | |
651 | ||
ccc3e6d9 | 652 | __key_get(key); |
b5f545c8 DH |
653 | key_ref = make_key_ref(key, 1); |
654 | break; | |
655 | ||
8bbf4976 | 656 | case KEY_SPEC_REQUESTOR_KEYRING: |
4bdf0bc3 | 657 | if (!ctx.cred->request_key_auth) |
8bbf4976 DH |
658 | goto error; |
659 | ||
4bdf0bc3 | 660 | down_read(&ctx.cred->request_key_auth->sem); |
f67dabbd | 661 | if (test_bit(KEY_FLAG_REVOKED, |
4bdf0bc3 | 662 | &ctx.cred->request_key_auth->flags)) { |
8bbf4976 DH |
663 | key_ref = ERR_PTR(-EKEYREVOKED); |
664 | key = NULL; | |
665 | } else { | |
146aa8b1 | 666 | rka = ctx.cred->request_key_auth->payload.data[0]; |
8bbf4976 | 667 | key = rka->dest_keyring; |
ccc3e6d9 | 668 | __key_get(key); |
8bbf4976 | 669 | } |
4bdf0bc3 | 670 | up_read(&ctx.cred->request_key_auth->sem); |
8bbf4976 DH |
671 | if (!key) |
672 | goto error; | |
673 | key_ref = make_key_ref(key, 1); | |
674 | break; | |
675 | ||
1da177e4 | 676 | default: |
664cceb0 | 677 | key_ref = ERR_PTR(-EINVAL); |
1da177e4 LT |
678 | if (id < 1) |
679 | goto error; | |
680 | ||
681 | key = key_lookup(id); | |
664cceb0 | 682 | if (IS_ERR(key)) { |
e231c2ee | 683 | key_ref = ERR_CAST(key); |
1da177e4 | 684 | goto error; |
664cceb0 DH |
685 | } |
686 | ||
687 | key_ref = make_key_ref(key, 0); | |
688 | ||
689 | /* check to see if we possess the key */ | |
4bdf0bc3 DH |
690 | ctx.index_key.type = key->type; |
691 | ctx.index_key.description = key->description; | |
692 | ctx.index_key.desc_len = strlen(key->description); | |
46291959 | 693 | ctx.match_data.raw_data = key; |
4bdf0bc3 DH |
694 | kdebug("check possessed"); |
695 | skey_ref = search_process_keyrings(&ctx); | |
696 | kdebug("possessed=%p", skey_ref); | |
664cceb0 DH |
697 | |
698 | if (!IS_ERR(skey_ref)) { | |
699 | key_put(key); | |
700 | key_ref = skey_ref; | |
701 | } | |
702 | ||
1da177e4 LT |
703 | break; |
704 | } | |
705 | ||
5593122e DH |
706 | /* unlink does not use the nominated key in any way, so can skip all |
707 | * the permission checks as it is only concerned with the keyring */ | |
708 | if (lflags & KEY_LOOKUP_FOR_UNLINK) { | |
709 | ret = 0; | |
710 | goto error; | |
711 | } | |
712 | ||
713 | if (!(lflags & KEY_LOOKUP_PARTIAL)) { | |
76181c13 DH |
714 | ret = wait_for_key_construction(key, true); |
715 | switch (ret) { | |
716 | case -ERESTARTSYS: | |
717 | goto invalid_key; | |
718 | default: | |
719 | if (perm) | |
720 | goto invalid_key; | |
721 | case 0: | |
722 | break; | |
723 | } | |
724 | } else if (perm) { | |
1da177e4 LT |
725 | ret = key_validate(key); |
726 | if (ret < 0) | |
727 | goto invalid_key; | |
728 | } | |
729 | ||
730 | ret = -EIO; | |
5593122e | 731 | if (!(lflags & KEY_LOOKUP_PARTIAL) && |
363b02da | 732 | key_read_state(key) == KEY_IS_UNINSTANTIATED) |
1da177e4 LT |
733 | goto invalid_key; |
734 | ||
3e30148c | 735 | /* check the permissions */ |
4bdf0bc3 | 736 | ret = key_task_permission(key_ref, ctx.cred, perm); |
29db9190 | 737 | if (ret < 0) |
1da177e4 LT |
738 | goto invalid_key; |
739 | ||
074d5898 | 740 | key->last_used_at = ktime_get_real_seconds(); |
31d5a79d | 741 | |
664cceb0 | 742 | error: |
4bdf0bc3 | 743 | put_cred(ctx.cred); |
664cceb0 | 744 | return key_ref; |
1da177e4 | 745 | |
664cceb0 DH |
746 | invalid_key: |
747 | key_ref_put(key_ref); | |
748 | key_ref = ERR_PTR(ret); | |
1da177e4 LT |
749 | goto error; |
750 | ||
bb952bb9 DH |
751 | /* if we attempted to install a keyring, then it may have caused new |
752 | * creds to be installed */ | |
753 | reget_creds: | |
4bdf0bc3 | 754 | put_cred(ctx.cred); |
bb952bb9 | 755 | goto try_again; |
a8b17ed0 | 756 | } |
76ef5e17 | 757 | EXPORT_SYMBOL(lookup_user_key); |
bb952bb9 | 758 | |
1da177e4 | 759 | /* |
973c9f4f DH |
760 | * Join the named keyring as the session keyring if possible else attempt to |
761 | * create a new one of that name and join that. | |
762 | * | |
763 | * If the name is NULL, an empty anonymous keyring will be installed as the | |
764 | * session keyring. | |
765 | * | |
766 | * Named session keyrings are joined with a semaphore held to prevent the | |
767 | * keyrings from going away whilst the attempt is made to going them and also | |
768 | * to prevent a race in creating compatible session keyrings. | |
1da177e4 LT |
769 | */ |
770 | long join_session_keyring(const char *name) | |
771 | { | |
d84f4f99 DH |
772 | const struct cred *old; |
773 | struct cred *new; | |
1da177e4 | 774 | struct key *keyring; |
d84f4f99 DH |
775 | long ret, serial; |
776 | ||
d84f4f99 DH |
777 | new = prepare_creds(); |
778 | if (!new) | |
779 | return -ENOMEM; | |
780 | old = current_cred(); | |
1da177e4 LT |
781 | |
782 | /* if no name is provided, install an anonymous keyring */ | |
783 | if (!name) { | |
d84f4f99 | 784 | ret = install_session_keyring_to_cred(new, NULL); |
1da177e4 LT |
785 | if (ret < 0) |
786 | goto error; | |
787 | ||
3a50597d | 788 | serial = new->session_keyring->serial; |
d84f4f99 DH |
789 | ret = commit_creds(new); |
790 | if (ret == 0) | |
791 | ret = serial; | |
792 | goto okay; | |
1da177e4 LT |
793 | } |
794 | ||
795 | /* allow the user to join or create a named keyring */ | |
bb003079 | 796 | mutex_lock(&key_session_mutex); |
1da177e4 LT |
797 | |
798 | /* look for an existing keyring of this name */ | |
69664cf1 | 799 | keyring = find_keyring_by_name(name, false); |
1da177e4 LT |
800 | if (PTR_ERR(keyring) == -ENOKEY) { |
801 | /* not found - try and create a new one */ | |
96b5c8fe DH |
802 | keyring = keyring_alloc( |
803 | name, old->uid, old->gid, old, | |
804 | KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK, | |
5ac7eace | 805 | KEY_ALLOC_IN_QUOTA, NULL, NULL); |
1da177e4 LT |
806 | if (IS_ERR(keyring)) { |
807 | ret = PTR_ERR(keyring); | |
bcf945d3 | 808 | goto error2; |
1da177e4 | 809 | } |
d84f4f99 | 810 | } else if (IS_ERR(keyring)) { |
1da177e4 LT |
811 | ret = PTR_ERR(keyring); |
812 | goto error2; | |
3a50597d DH |
813 | } else if (keyring == new->session_keyring) { |
814 | ret = 0; | |
d636bd9f | 815 | goto error3; |
1da177e4 LT |
816 | } |
817 | ||
818 | /* we've got a keyring - now to install it */ | |
d84f4f99 | 819 | ret = install_session_keyring_to_cred(new, keyring); |
1da177e4 | 820 | if (ret < 0) |
d636bd9f | 821 | goto error3; |
1da177e4 | 822 | |
d84f4f99 DH |
823 | commit_creds(new); |
824 | mutex_unlock(&key_session_mutex); | |
825 | ||
1da177e4 LT |
826 | ret = keyring->serial; |
827 | key_put(keyring); | |
d84f4f99 DH |
828 | okay: |
829 | return ret; | |
1da177e4 | 830 | |
d636bd9f EB |
831 | error3: |
832 | key_put(keyring); | |
664cceb0 | 833 | error2: |
bb003079 | 834 | mutex_unlock(&key_session_mutex); |
664cceb0 | 835 | error: |
d84f4f99 | 836 | abort_creds(new); |
1da177e4 | 837 | return ret; |
d84f4f99 | 838 | } |
ee18d64c DH |
839 | |
840 | /* | |
973c9f4f DH |
841 | * Replace a process's session keyring on behalf of one of its children when |
842 | * the target process is about to resume userspace execution. | |
ee18d64c | 843 | */ |
67d12145 | 844 | void key_change_session_keyring(struct callback_head *twork) |
ee18d64c | 845 | { |
413cd3d9 | 846 | const struct cred *old = current_cred(); |
67d12145 | 847 | struct cred *new = container_of(twork, struct cred, rcu); |
ee18d64c | 848 | |
413cd3d9 ON |
849 | if (unlikely(current->flags & PF_EXITING)) { |
850 | put_cred(new); | |
ee18d64c | 851 | return; |
413cd3d9 | 852 | } |
ee18d64c | 853 | |
ee18d64c DH |
854 | new-> uid = old-> uid; |
855 | new-> euid = old-> euid; | |
856 | new-> suid = old-> suid; | |
857 | new->fsuid = old->fsuid; | |
858 | new-> gid = old-> gid; | |
859 | new-> egid = old-> egid; | |
860 | new-> sgid = old-> sgid; | |
861 | new->fsgid = old->fsgid; | |
862 | new->user = get_uid(old->user); | |
ba0e3427 | 863 | new->user_ns = get_user_ns(old->user_ns); |
ee18d64c DH |
864 | new->group_info = get_group_info(old->group_info); |
865 | ||
866 | new->securebits = old->securebits; | |
867 | new->cap_inheritable = old->cap_inheritable; | |
868 | new->cap_permitted = old->cap_permitted; | |
869 | new->cap_effective = old->cap_effective; | |
58319057 | 870 | new->cap_ambient = old->cap_ambient; |
ee18d64c DH |
871 | new->cap_bset = old->cap_bset; |
872 | ||
873 | new->jit_keyring = old->jit_keyring; | |
874 | new->thread_keyring = key_get(old->thread_keyring); | |
3a50597d | 875 | new->process_keyring = key_get(old->process_keyring); |
ee18d64c DH |
876 | |
877 | security_transfer_creds(new, old); | |
878 | ||
879 | commit_creds(new); | |
880 | } | |
c124bde2 MZ |
881 | |
882 | /* | |
883 | * Make sure that root's user and user-session keyrings exist. | |
884 | */ | |
885 | static int __init init_root_keyring(void) | |
886 | { | |
887 | return install_user_keyrings(); | |
888 | } | |
889 | ||
890 | late_initcall(init_root_keyring); |