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d410fa4 Create Documentation/security/,
Randy Dunlap authored
1 /* Task credentials management - see Documentation/security/credentials.txt
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David Howells authored
2 *
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11 #include <linux/module.h>
12 #include <linux/cred.h>
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13 #include <linux/slab.h>
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14 #include <linux/sched.h>
15 #include <linux/key.h>
16 #include <linux/keyctl.h>
17 #include <linux/init_task.h>
18 #include <linux/security.h>
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19 #include <linux/cn_proc.h>
20
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21 #if 0
22 #define kdebug(FMT, ...) \
23 printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid ,##__VA_ARGS__)
24 #else
25 #define kdebug(FMT, ...) \
26 no_printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid ,##__VA_ARGS__)
27 #endif
28
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29 static struct kmem_cache *cred_jar;
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30
31 /*
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32 * The common credentials for the initial task's thread group
33 */
34 #ifdef CONFIG_KEYS
35 static struct thread_group_cred init_tgcred = {
36 .usage = ATOMIC_INIT(2),
37 .tgid = 0,
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38 .lock = __SPIN_LOCK_UNLOCKED(init_cred.tgcred.lock),
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39 };
40 #endif
41
42 /*
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43 * The initial credentials for the initial task
44 */
45 struct cred init_cred = {
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46 .usage = ATOMIC_INIT(4),
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47 #ifdef CONFIG_DEBUG_CREDENTIALS
48 .subscribers = ATOMIC_INIT(2),
49 .magic = CRED_MAGIC,
50 #endif
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51 .securebits = SECUREBITS_DEFAULT,
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52 .cap_inheritable = CAP_EMPTY_SET,
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53 .cap_permitted = CAP_FULL_SET,
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54 .cap_effective = CAP_FULL_SET,
55 .cap_bset = CAP_FULL_SET,
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56 .user = INIT_USER,
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57 .user_ns = &init_user_ns,
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58 .group_info = &init_groups,
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59 #ifdef CONFIG_KEYS
60 .tgcred = &init_tgcred,
61 #endif
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62 };
63
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64 static inline void set_cred_subscribers(struct cred *cred, int n)
65 {
66 #ifdef CONFIG_DEBUG_CREDENTIALS
67 atomic_set(&cred->subscribers, n);
68 #endif
69 }
70
71 static inline int read_cred_subscribers(const struct cred *cred)
72 {
73 #ifdef CONFIG_DEBUG_CREDENTIALS
74 return atomic_read(&cred->subscribers);
75 #else
76 return 0;
77 #endif
78 }
79
80 static inline void alter_cred_subscribers(const struct cred *_cred, int n)
81 {
82 #ifdef CONFIG_DEBUG_CREDENTIALS
83 struct cred *cred = (struct cred *) _cred;
84
85 atomic_add(n, &cred->subscribers);
86 #endif
87 }
88
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89 /*
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90 * Dispose of the shared task group credentials
91 */
92 #ifdef CONFIG_KEYS
93 static void release_tgcred_rcu(struct rcu_head *rcu)
94 {
95 struct thread_group_cred *tgcred =
96 container_of(rcu, struct thread_group_cred, rcu);
97
98 BUG_ON(atomic_read(&tgcred->usage) != 0);
99
100 key_put(tgcred->session_keyring);
101 key_put(tgcred->process_keyring);
102 kfree(tgcred);
103 }
104 #endif
105
106 /*
107 * Release a set of thread group credentials.
108 */
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109 static void release_tgcred(struct cred *cred)
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110 {
111 #ifdef CONFIG_KEYS
112 struct thread_group_cred *tgcred = cred->tgcred;
113
114 if (atomic_dec_and_test(&tgcred->usage))
115 call_rcu(&tgcred->rcu, release_tgcred_rcu);
116 #endif
117 }
118
119 /*
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120 * The RCU callback to actually dispose of a set of credentials
121 */
122 static void put_cred_rcu(struct rcu_head *rcu)
123 {
124 struct cred *cred = container_of(rcu, struct cred, rcu);
125
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126 kdebug("put_cred_rcu(%p)", cred);
127
128 #ifdef CONFIG_DEBUG_CREDENTIALS
129 if (cred->magic != CRED_MAGIC_DEAD ||
130 atomic_read(&cred->usage) != 0 ||
131 read_cred_subscribers(cred) != 0)
132 panic("CRED: put_cred_rcu() sees %p with"
133 " mag %x, put %p, usage %d, subscr %d\n",
134 cred, cred->magic, cred->put_addr,
135 atomic_read(&cred->usage),
136 read_cred_subscribers(cred));
137 #else
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138 if (atomic_read(&cred->usage) != 0)
139 panic("CRED: put_cred_rcu() sees %p with usage %d\n",
140 cred, atomic_read(&cred->usage));
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141 #endif
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142
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143 security_cred_free(cred);
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144 key_put(cred->thread_keyring);
145 key_put(cred->request_key_auth);
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146 release_tgcred(cred);
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147 if (cred->group_info)
148 put_group_info(cred->group_info);
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149 free_uid(cred->user);
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150 kmem_cache_free(cred_jar, cred);
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151 }
152
153 /**
154 * __put_cred - Destroy a set of credentials
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155 * @cred: The record to release
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156 *
157 * Destroy a set of credentials on which no references remain.
158 */
159 void __put_cred(struct cred *cred)
160 {
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161 kdebug("__put_cred(%p{%d,%d})", cred,
162 atomic_read(&cred->usage),
163 read_cred_subscribers(cred));
164
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165 BUG_ON(atomic_read(&cred->usage) != 0);
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166 #ifdef CONFIG_DEBUG_CREDENTIALS
167 BUG_ON(read_cred_subscribers(cred) != 0);
168 cred->magic = CRED_MAGIC_DEAD;
169 cred->put_addr = __builtin_return_address(0);
170 #endif
171 BUG_ON(cred == current->cred);
172 BUG_ON(cred == current->real_cred);
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173
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174 call_rcu(&cred->rcu, put_cred_rcu);
175 }
176 EXPORT_SYMBOL(__put_cred);
177
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178 /*
179 * Clean up a task's credentials when it exits
180 */
181 void exit_creds(struct task_struct *tsk)
182 {
183 struct cred *cred;
184
185 kdebug("exit_creds(%u,%p,%p,{%d,%d})", tsk->pid, tsk->real_cred, tsk->cred,
186 atomic_read(&tsk->cred->usage),
187 read_cred_subscribers(tsk->cred));
188
189 cred = (struct cred *) tsk->real_cred;
190 tsk->real_cred = NULL;
191 validate_creds(cred);
192 alter_cred_subscribers(cred, -1);
193 put_cred(cred);
194
195 cred = (struct cred *) tsk->cred;
196 tsk->cred = NULL;
197 validate_creds(cred);
198 alter_cred_subscribers(cred, -1);
199 put_cred(cred);
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200
201 cred = (struct cred *) tsk->replacement_session_keyring;
202 if (cred) {
203 tsk->replacement_session_keyring = NULL;
204 validate_creds(cred);
205 put_cred(cred);
206 }
207 }
208
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209 /**
210 * get_task_cred - Get another task's objective credentials
211 * @task: The task to query
212 *
213 * Get the objective credentials of a task, pinning them so that they can't go
214 * away. Accessing a task's credentials directly is not permitted.
215 *
216 * The caller must also make sure task doesn't get deleted, either by holding a
217 * ref on task or by holding tasklist_lock to prevent it from being unlinked.
218 */
219 const struct cred *get_task_cred(struct task_struct *task)
220 {
221 const struct cred *cred;
222
223 rcu_read_lock();
224
225 do {
226 cred = __task_cred((task));
227 BUG_ON(!cred);
228 } while (!atomic_inc_not_zero(&((struct cred *)cred)->usage));
229
230 rcu_read_unlock();
231 return cred;
232 }
233
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234 /*
235 * Allocate blank credentials, such that the credentials can be filled in at a
236 * later date without risk of ENOMEM.
237 */
238 struct cred *cred_alloc_blank(void)
239 {
240 struct cred *new;
241
242 new = kmem_cache_zalloc(cred_jar, GFP_KERNEL);
243 if (!new)
244 return NULL;
245
246 #ifdef CONFIG_KEYS
247 new->tgcred = kzalloc(sizeof(*new->tgcred), GFP_KERNEL);
248 if (!new->tgcred) {
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249 kmem_cache_free(cred_jar, new);
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250 return NULL;
251 }
252 atomic_set(&new->tgcred->usage, 1);
253 #endif
254
255 atomic_set(&new->usage, 1);
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256 #ifdef CONFIG_DEBUG_CREDENTIALS
257 new->magic = CRED_MAGIC;
258 #endif
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259
260 if (security_cred_alloc_blank(new, GFP_KERNEL) < 0)
261 goto error;
262
263 return new;
264
265 error:
266 abort_creds(new);
267 return NULL;
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268 }
269
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270 /**
271 * prepare_creds - Prepare a new set of credentials for modification
272 *
273 * Prepare a new set of task credentials for modification. A task's creds
274 * shouldn't generally be modified directly, therefore this function is used to
275 * prepare a new copy, which the caller then modifies and then commits by
276 * calling commit_creds().
277 *
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278 * Preparation involves making a copy of the objective creds for modification.
279 *
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280 * Returns a pointer to the new creds-to-be if successful, NULL otherwise.
281 *
282 * Call commit_creds() or abort_creds() to clean up.
283 */
284 struct cred *prepare_creds(void)
285 {
286 struct task_struct *task = current;
287 const struct cred *old;
288 struct cred *new;
289
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290 validate_process_creds();
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291
292 new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
293 if (!new)
294 return NULL;
295
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296 kdebug("prepare_creds() alloc %p", new);
297
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298 old = task->cred;
299 memcpy(new, old, sizeof(struct cred));
300
301 atomic_set(&new->usage, 1);
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302 set_cred_subscribers(new, 0);
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303 get_group_info(new->group_info);
304 get_uid(new->user);
305
306 #ifdef CONFIG_KEYS
307 key_get(new->thread_keyring);
308 key_get(new->request_key_auth);
309 atomic_inc(&new->tgcred->usage);
310 #endif
311
312 #ifdef CONFIG_SECURITY
313 new->security = NULL;
314 #endif
315
316 if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
317 goto error;
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318 validate_creds(new);
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319 return new;
320
321 error:
322 abort_creds(new);
323 return NULL;
324 }
325 EXPORT_SYMBOL(prepare_creds);
326
327 /*
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328 * Prepare credentials for current to perform an execve()
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329 * - The caller must hold ->cred_guard_mutex
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330 */
331 struct cred *prepare_exec_creds(void)
332 {
333 struct thread_group_cred *tgcred = NULL;
334 struct cred *new;
335
336 #ifdef CONFIG_KEYS
337 tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
338 if (!tgcred)
339 return NULL;
340 #endif
341
342 new = prepare_creds();
343 if (!new) {
344 kfree(tgcred);
345 return new;
346 }
347
348 #ifdef CONFIG_KEYS
349 /* newly exec'd tasks don't get a thread keyring */
350 key_put(new->thread_keyring);
351 new->thread_keyring = NULL;
352
353 /* create a new per-thread-group creds for all this set of threads to
354 * share */
355 memcpy(tgcred, new->tgcred, sizeof(struct thread_group_cred));
356
357 atomic_set(&tgcred->usage, 1);
358 spin_lock_init(&tgcred->lock);
359
360 /* inherit the session keyring; new process keyring */
361 key_get(tgcred->session_keyring);
362 tgcred->process_keyring = NULL;
363
364 release_tgcred(new);
365 new->tgcred = tgcred;
366 #endif
367
368 return new;
369 }
370
371 /*
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372 * Copy credentials for the new process created by fork()
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373 *
374 * We share if we can, but under some circumstances we have to generate a new
375 * set.
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376 *
377 * The new process gets the current process's subjective credentials as its
378 * objective and subjective credentials
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379 */
380 int copy_creds(struct task_struct *p, unsigned long clone_flags)
381 {
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382 #ifdef CONFIG_KEYS
383 struct thread_group_cred *tgcred;
384 #endif
385 struct cred *new;
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386 int ret;
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387
388 if (
389 #ifdef CONFIG_KEYS
390 !p->cred->thread_keyring &&
391 #endif
392 clone_flags & CLONE_THREAD
393 ) {
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394 p->real_cred = get_cred(p->cred);
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395 get_cred(p->cred);
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396 alter_cred_subscribers(p->cred, 2);
397 kdebug("share_creds(%p{%d,%d})",
398 p->cred, atomic_read(&p->cred->usage),
399 read_cred_subscribers(p->cred));
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400 atomic_inc(&p->cred->user->processes);
401 return 0;
402 }
403
404 new = prepare_creds();
405 if (!new)
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406 return -ENOMEM;
407
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408 if (clone_flags & CLONE_NEWUSER) {
409 ret = create_user_ns(new);
410 if (ret < 0)
411 goto error_put;
412 }
413
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414 /* cache user_ns in cred. Doesn't need a refcount because it will
415 * stay pinned by cred->user
416 */
417 new->user_ns = new->user->user_ns;
418
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419 #ifdef CONFIG_KEYS
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420 /* new threads get their own thread keyrings if their parent already
421 * had one */
422 if (new->thread_keyring) {
423 key_put(new->thread_keyring);
424 new->thread_keyring = NULL;
425 if (clone_flags & CLONE_THREAD)
426 install_thread_keyring_to_cred(new);
427 }
428
429 /* we share the process and session keyrings between all the threads in
430 * a process - this is slightly icky as we violate COW credentials a
431 * bit */
432 if (!(clone_flags & CLONE_THREAD)) {
433 tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
434 if (!tgcred) {
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435 ret = -ENOMEM;
436 goto error_put;
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437 }
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438 atomic_set(&tgcred->usage, 1);
439 spin_lock_init(&tgcred->lock);
440 tgcred->process_keyring = NULL;
441 tgcred->session_keyring = key_get(new->tgcred->session_keyring);
442
443 release_tgcred(new);
444 new->tgcred = tgcred;
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445 }
446 #endif
447
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448 atomic_inc(&new->user->processes);
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449 p->cred = p->real_cred = get_cred(new);
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450 alter_cred_subscribers(new, 2);
451 validate_creds(new);
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452 return 0;
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453
454 error_put:
455 put_cred(new);
456 return ret;
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457 }
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458
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459 /**
460 * commit_creds - Install new credentials upon the current task
461 * @new: The credentials to be assigned
462 *
463 * Install a new set of credentials to the current task, using RCU to replace
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464 * the old set. Both the objective and the subjective credentials pointers are
465 * updated. This function may not be called if the subjective credentials are
466 * in an overridden state.
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467 *
468 * This function eats the caller's reference to the new credentials.
469 *
470 * Always returns 0 thus allowing this function to be tail-called at the end
471 * of, say, sys_setgid().
472 */
473 int commit_creds(struct cred *new)
474 {
475 struct task_struct *task = current;
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476 const struct cred *old = task->real_cred;
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477
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478 kdebug("commit_creds(%p{%d,%d})", new,
479 atomic_read(&new->usage),
480 read_cred_subscribers(new));
481
482 BUG_ON(task->cred != old);
483 #ifdef CONFIG_DEBUG_CREDENTIALS
484 BUG_ON(read_cred_subscribers(old) < 2);
485 validate_creds(old);
486 validate_creds(new);
487 #endif
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488 BUG_ON(atomic_read(&new->usage) < 1);
489
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490 get_cred(new); /* we will require a ref for the subj creds too */
491
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492 /* dumpability changes */
493 if (old->euid != new->euid ||
494 old->egid != new->egid ||
495 old->fsuid != new->fsuid ||
496 old->fsgid != new->fsgid ||
497 !cap_issubset(new->cap_permitted, old->cap_permitted)) {
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498 if (task->mm)
499 set_dumpable(task->mm, suid_dumpable);
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500 task->pdeath_signal = 0;
501 smp_wmb();
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502 }
503
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504 /* alter the thread keyring */
505 if (new->fsuid != old->fsuid)
506 key_fsuid_changed(task);
507 if (new->fsgid != old->fsgid)
508 key_fsgid_changed(task);
509
510 /* do it
72fa599 move RLIMIT_NPROC check from set_user() to do_execve_common()
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511 * RLIMIT_NPROC limits on user->processes have already been checked
512 * in set_user().
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513 */
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514 alter_cred_subscribers(new, 2);
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515 if (new->user != old->user)
516 atomic_inc(&new->user->processes);
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517 rcu_assign_pointer(task->real_cred, new);
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518 rcu_assign_pointer(task->cred, new);
519 if (new->user != old->user)
520 atomic_dec(&old->user->processes);
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521 alter_cred_subscribers(old, -2);
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522
523 /* send notifications */
524 if (new->uid != old->uid ||
525 new->euid != old->euid ||
526 new->suid != old->suid ||
527 new->fsuid != old->fsuid)
528 proc_id_connector(task, PROC_EVENT_UID);
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529
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530 if (new->gid != old->gid ||
531 new->egid != old->egid ||
532 new->sgid != old->sgid ||
533 new->fsgid != old->fsgid)
534 proc_id_connector(task, PROC_EVENT_GID);
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535
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536 /* release the old obj and subj refs both */
537 put_cred(old);
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538 put_cred(old);
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539 return 0;
540 }
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541 EXPORT_SYMBOL(commit_creds);
542
543 /**
544 * abort_creds - Discard a set of credentials and unlock the current task
545 * @new: The credentials that were going to be applied
546 *
547 * Discard a set of credentials that were under construction and unlock the
548 * current task.
549 */
550 void abort_creds(struct cred *new)
551 {
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552 kdebug("abort_creds(%p{%d,%d})", new,
553 atomic_read(&new->usage),
554 read_cred_subscribers(new));
555
556 #ifdef CONFIG_DEBUG_CREDENTIALS
557 BUG_ON(read_cred_subscribers(new) != 0);
558 #endif
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559 BUG_ON(atomic_read(&new->usage) < 1);
560 put_cred(new);
561 }
562 EXPORT_SYMBOL(abort_creds);
563
564 /**
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David Howells authored
565 * override_creds - Override the current process's subjective credentials
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566 * @new: The credentials to be assigned
567 *
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568 * Install a set of temporary override subjective credentials on the current
569 * process, returning the old set for later reversion.
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570 */
571 const struct cred *override_creds(const struct cred *new)
572 {
573 const struct cred *old = current->cred;
574
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575 kdebug("override_creds(%p{%d,%d})", new,
576 atomic_read(&new->usage),
577 read_cred_subscribers(new));
578
579 validate_creds(old);
580 validate_creds(new);
581 get_cred(new);
582 alter_cred_subscribers(new, 1);
583 rcu_assign_pointer(current->cred, new);
584 alter_cred_subscribers(old, -1);
585
586 kdebug("override_creds() = %p{%d,%d}", old,
587 atomic_read(&old->usage),
588 read_cred_subscribers(old));
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589 return old;
590 }
591 EXPORT_SYMBOL(override_creds);
592
593 /**
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David Howells authored
594 * revert_creds - Revert a temporary subjective credentials override
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595 * @old: The credentials to be restored
596 *
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597 * Revert a temporary set of override subjective credentials to an old set,
598 * discarding the override set.
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599 */
600 void revert_creds(const struct cred *old)
601 {
602 const struct cred *override = current->cred;
603
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604 kdebug("revert_creds(%p{%d,%d})", old,
605 atomic_read(&old->usage),
606 read_cred_subscribers(old));
607
608 validate_creds(old);
609 validate_creds(override);
610 alter_cred_subscribers(old, 1);
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611 rcu_assign_pointer(current->cred, old);
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612 alter_cred_subscribers(override, -1);
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613 put_cred(override);
614 }
615 EXPORT_SYMBOL(revert_creds);
616
617 /*
618 * initialise the credentials stuff
619 */
620 void __init cred_init(void)
621 {
622 /* allocate a slab in which we can store credentials */
623 cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred),
624 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
625 }
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626
627 /**
628 * prepare_kernel_cred - Prepare a set of credentials for a kernel service
629 * @daemon: A userspace daemon to be used as a reference
630 *
631 * Prepare a set of credentials for a kernel service. This can then be used to
632 * override a task's own credentials so that work can be done on behalf of that
633 * task that requires a different subjective context.
634 *
635 * @daemon is used to provide a base for the security record, but can be NULL.
636 * If @daemon is supplied, then the security data will be derived from that;
637 * otherwise they'll be set to 0 and no groups, full capabilities and no keys.
638 *
639 * The caller may change these controls afterwards if desired.
640 *
641 * Returns the new credentials or NULL if out of memory.
642 *
643 * Does not take, and does not return holding current->cred_replace_mutex.
644 */
645 struct cred *prepare_kernel_cred(struct task_struct *daemon)
646 {
647 const struct cred *old;
648 struct cred *new;
649
650 new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
651 if (!new)
652 return NULL;
653
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654 kdebug("prepare_kernel_cred() alloc %p", new);
655
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656 if (daemon)
657 old = get_task_cred(daemon);
658 else
659 old = get_cred(&init_cred);
660
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661 validate_creds(old);
662
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663 *new = *old;
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664 atomic_set(&new->usage, 1);
665 set_cred_subscribers(new, 0);
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666 get_uid(new->user);
667 get_group_info(new->group_info);
668
669 #ifdef CONFIG_KEYS
670 atomic_inc(&init_tgcred.usage);
671 new->tgcred = &init_tgcred;
672 new->request_key_auth = NULL;
673 new->thread_keyring = NULL;
674 new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
675 #endif
676
677 #ifdef CONFIG_SECURITY
678 new->security = NULL;
679 #endif
680 if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
681 goto error;
682
683 put_cred(old);
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684 validate_creds(new);
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685 return new;
686
687 error:
688 put_cred(new);
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689 put_cred(old);
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690 return NULL;
691 }
692 EXPORT_SYMBOL(prepare_kernel_cred);
693
694 /**
695 * set_security_override - Set the security ID in a set of credentials
696 * @new: The credentials to alter
697 * @secid: The LSM security ID to set
698 *
699 * Set the LSM security ID in a set of credentials so that the subjective
700 * security is overridden when an alternative set of credentials is used.
701 */
702 int set_security_override(struct cred *new, u32 secid)
703 {
704 return security_kernel_act_as(new, secid);
705 }
706 EXPORT_SYMBOL(set_security_override);
707
708 /**
709 * set_security_override_from_ctx - Set the security ID in a set of credentials
710 * @new: The credentials to alter
711 * @secctx: The LSM security context to generate the security ID from.
712 *
713 * Set the LSM security ID in a set of credentials so that the subjective
714 * security is overridden when an alternative set of credentials is used. The
715 * security ID is specified in string form as a security context to be
716 * interpreted by the LSM.
717 */
718 int set_security_override_from_ctx(struct cred *new, const char *secctx)
719 {
720 u32 secid;
721 int ret;
722
723 ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
724 if (ret < 0)
725 return ret;
726
727 return set_security_override(new, secid);
728 }
729 EXPORT_SYMBOL(set_security_override_from_ctx);
730
731 /**
732 * set_create_files_as - Set the LSM file create context in a set of credentials
733 * @new: The credentials to alter
734 * @inode: The inode to take the context from
735 *
736 * Change the LSM file creation context in a set of credentials to be the same
737 * as the object context of the specified inode, so that the new inodes have
738 * the same MAC context as that inode.
739 */
740 int set_create_files_as(struct cred *new, struct inode *inode)
741 {
742 new->fsuid = inode->i_uid;
743 new->fsgid = inode->i_gid;
744 return security_kernel_create_files_as(new, inode);
745 }
746 EXPORT_SYMBOL(set_create_files_as);
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747
748 #ifdef CONFIG_DEBUG_CREDENTIALS
749
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Andrew Morton authored
750 bool creds_are_invalid(const struct cred *cred)
751 {
752 if (cred->magic != CRED_MAGIC)
753 return true;
754 #ifdef CONFIG_SECURITY_SELINUX
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Tetsuo Handa authored
755 /*
756 * cred->security == NULL if security_cred_alloc_blank() or
757 * security_prepare_creds() returned an error.
758 */
759 if (selinux_is_enabled() && cred->security) {
74908a0 include/linux/cred.h: fix build
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760 if ((unsigned long) cred->security < PAGE_SIZE)
761 return true;
762 if ((*(u32 *)cred->security & 0xffffff00) ==
763 (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8))
764 return true;
765 }
766 #endif
767 return false;
768 }
764db03 creds_are_invalid() needs to be exported for use by modules:
Randy Dunlap authored
769 EXPORT_SYMBOL(creds_are_invalid);
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770
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771 /*
772 * dump invalid credentials
773 */
774 static void dump_invalid_creds(const struct cred *cred, const char *label,
775 const struct task_struct *tsk)
776 {
777 printk(KERN_ERR "CRED: %s credentials: %p %s%s%s\n",
778 label, cred,
779 cred == &init_cred ? "[init]" : "",
780 cred == tsk->real_cred ? "[real]" : "",
781 cred == tsk->cred ? "[eff]" : "");
782 printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p\n",
783 cred->magic, cred->put_addr);
784 printk(KERN_ERR "CRED: ->usage=%d, subscr=%d\n",
785 atomic_read(&cred->usage),
786 read_cred_subscribers(cred));
787 printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d }\n",
788 cred->uid, cred->euid, cred->suid, cred->fsuid);
789 printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d }\n",
790 cred->gid, cred->egid, cred->sgid, cred->fsgid);
791 #ifdef CONFIG_SECURITY
792 printk(KERN_ERR "CRED: ->security is %p\n", cred->security);
793 if ((unsigned long) cred->security >= PAGE_SIZE &&
794 (((unsigned long) cred->security & 0xffffff00) !=
795 (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8)))
796 printk(KERN_ERR "CRED: ->security {%x, %x}\n",
797 ((u32*)cred->security)[0],
798 ((u32*)cred->security)[1]);
799 #endif
800 }
801
802 /*
803 * report use of invalid credentials
804 */
805 void __invalid_creds(const struct cred *cred, const char *file, unsigned line)
806 {
807 printk(KERN_ERR "CRED: Invalid credentials\n");
808 printk(KERN_ERR "CRED: At %s:%u\n", file, line);
809 dump_invalid_creds(cred, "Specified", current);
810 BUG();
811 }
812 EXPORT_SYMBOL(__invalid_creds);
813
814 /*
815 * check the credentials on a process
816 */
817 void __validate_process_creds(struct task_struct *tsk,
818 const char *file, unsigned line)
819 {
820 if (tsk->cred == tsk->real_cred) {
821 if (unlikely(read_cred_subscribers(tsk->cred) < 2 ||
822 creds_are_invalid(tsk->cred)))
823 goto invalid_creds;
824 } else {
825 if (unlikely(read_cred_subscribers(tsk->real_cred) < 1 ||
826 read_cred_subscribers(tsk->cred) < 1 ||
827 creds_are_invalid(tsk->real_cred) ||
828 creds_are_invalid(tsk->cred)))
829 goto invalid_creds;
830 }
831 return;
832
833 invalid_creds:
834 printk(KERN_ERR "CRED: Invalid process credentials\n");
835 printk(KERN_ERR "CRED: At %s:%u\n", file, line);
836
837 dump_invalid_creds(tsk->real_cred, "Real", tsk);
838 if (tsk->cred != tsk->real_cred)
839 dump_invalid_creds(tsk->cred, "Effective", tsk);
840 else
841 printk(KERN_ERR "CRED: Effective creds == Real creds\n");
842 BUG();
843 }
844 EXPORT_SYMBOL(__validate_process_creds);
845
846 /*
847 * check creds for do_exit()
848 */
849 void validate_creds_for_do_exit(struct task_struct *tsk)
850 {
851 kdebug("validate_creds_for_do_exit(%p,%p{%d,%d})",
852 tsk->real_cred, tsk->cred,
853 atomic_read(&tsk->cred->usage),
854 read_cred_subscribers(tsk->cred));
855
856 __validate_process_creds(tsk, __FILE__, __LINE__);
857 }
858
859 #endif /* CONFIG_DEBUG_CREDENTIALS */
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