Blame view
kernel/cred.c
21.2 KB
d410fa4ef
|
1 |
/* Task credentials management - see Documentation/security/credentials.txt |
f1752eec6
|
2 3 4 5 6 7 8 9 10 |
* * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public Licence * as published by the Free Software Foundation; either version * 2 of the Licence, or (at your option) any later version. */ |
9984de1a5
|
11 |
#include <linux/export.h> |
f1752eec6
|
12 |
#include <linux/cred.h> |
5a0e3ad6a
|
13 |
#include <linux/slab.h> |
f1752eec6
|
14 15 16 17 18 |
#include <linux/sched.h> #include <linux/key.h> #include <linux/keyctl.h> #include <linux/init_task.h> #include <linux/security.h> |
404015308
|
19 |
#include <linux/binfmts.h> |
d84f4f992
|
20 |
#include <linux/cn_proc.h> |
d84f4f992
|
21 |
|
e0e817392
|
22 23 24 25 26 |
#if 0 #define kdebug(FMT, ...) \ printk("[%-5.5s%5u] "FMT" ", current->comm, current->pid ,##__VA_ARGS__) #else |
e0e817392
|
27 28 29 30 |
#define kdebug(FMT, ...) \ no_printk("[%-5.5s%5u] "FMT" ", current->comm, current->pid ,##__VA_ARGS__) #endif |
d84f4f992
|
31 |
static struct kmem_cache *cred_jar; |
f1752eec6
|
32 33 34 35 36 |
/* * The initial credentials for the initial task */ struct cred init_cred = { |
3b11a1dec
|
37 |
.usage = ATOMIC_INIT(4), |
e0e817392
|
38 39 40 41 |
#ifdef CONFIG_DEBUG_CREDENTIALS .subscribers = ATOMIC_INIT(2), .magic = CRED_MAGIC, #endif |
078de5f70
|
42 43 44 45 46 47 48 49 |
.uid = GLOBAL_ROOT_UID, .gid = GLOBAL_ROOT_GID, .suid = GLOBAL_ROOT_UID, .sgid = GLOBAL_ROOT_GID, .euid = GLOBAL_ROOT_UID, .egid = GLOBAL_ROOT_GID, .fsuid = GLOBAL_ROOT_UID, .fsgid = GLOBAL_ROOT_GID, |
f1752eec6
|
50 |
.securebits = SECUREBITS_DEFAULT, |
a3232d2fa
|
51 |
.cap_inheritable = CAP_EMPTY_SET, |
f1752eec6
|
52 |
.cap_permitted = CAP_FULL_SET, |
a3232d2fa
|
53 54 |
.cap_effective = CAP_FULL_SET, .cap_bset = CAP_FULL_SET, |
f1752eec6
|
55 |
.user = INIT_USER, |
47a150edc
|
56 |
.user_ns = &init_user_ns, |
f1752eec6
|
57 58 |
.group_info = &init_groups, }; |
e0e817392
|
59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 |
static inline void set_cred_subscribers(struct cred *cred, int n) { #ifdef CONFIG_DEBUG_CREDENTIALS atomic_set(&cred->subscribers, n); #endif } static inline int read_cred_subscribers(const struct cred *cred) { #ifdef CONFIG_DEBUG_CREDENTIALS return atomic_read(&cred->subscribers); #else return 0; #endif } static inline void alter_cred_subscribers(const struct cred *_cred, int n) { #ifdef CONFIG_DEBUG_CREDENTIALS struct cred *cred = (struct cred *) _cred; atomic_add(n, &cred->subscribers); #endif } |
f1752eec6
|
83 84 85 86 87 88 |
/* * The RCU callback to actually dispose of a set of credentials */ static void put_cred_rcu(struct rcu_head *rcu) { struct cred *cred = container_of(rcu, struct cred, rcu); |
e0e817392
|
89 90 91 92 93 94 95 96 97 98 99 100 101 |
kdebug("put_cred_rcu(%p)", cred); #ifdef CONFIG_DEBUG_CREDENTIALS if (cred->magic != CRED_MAGIC_DEAD || atomic_read(&cred->usage) != 0 || read_cred_subscribers(cred) != 0) panic("CRED: put_cred_rcu() sees %p with" " mag %x, put %p, usage %d, subscr %d ", cred, cred->magic, cred->put_addr, atomic_read(&cred->usage), read_cred_subscribers(cred)); #else |
d84f4f992
|
102 103 104 105 |
if (atomic_read(&cred->usage) != 0) panic("CRED: put_cred_rcu() sees %p with usage %d ", cred, atomic_read(&cred->usage)); |
e0e817392
|
106 |
#endif |
f1752eec6
|
107 |
|
d84f4f992
|
108 |
security_cred_free(cred); |
3a50597de
|
109 110 |
key_put(cred->session_keyring); key_put(cred->process_keyring); |
f1752eec6
|
111 112 |
key_put(cred->thread_keyring); key_put(cred->request_key_auth); |
4a5d6ba19
|
113 114 |
if (cred->group_info) put_group_info(cred->group_info); |
f1752eec6
|
115 |
free_uid(cred->user); |
0093ccb68
|
116 |
put_user_ns(cred->user_ns); |
d84f4f992
|
117 |
kmem_cache_free(cred_jar, cred); |
f1752eec6
|
118 119 120 121 |
} /** * __put_cred - Destroy a set of credentials |
d84f4f992
|
122 |
* @cred: The record to release |
f1752eec6
|
123 124 125 126 127 |
* * Destroy a set of credentials on which no references remain. */ void __put_cred(struct cred *cred) { |
e0e817392
|
128 129 130 |
kdebug("__put_cred(%p{%d,%d})", cred, atomic_read(&cred->usage), read_cred_subscribers(cred)); |
d84f4f992
|
131 |
BUG_ON(atomic_read(&cred->usage) != 0); |
e0e817392
|
132 133 134 135 136 137 138 |
#ifdef CONFIG_DEBUG_CREDENTIALS BUG_ON(read_cred_subscribers(cred) != 0); cred->magic = CRED_MAGIC_DEAD; cred->put_addr = __builtin_return_address(0); #endif BUG_ON(cred == current->cred); BUG_ON(cred == current->real_cred); |
d84f4f992
|
139 |
|
f1752eec6
|
140 141 142 |
call_rcu(&cred->rcu, put_cred_rcu); } EXPORT_SYMBOL(__put_cred); |
e0e817392
|
143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 |
/* * Clean up a task's credentials when it exits */ void exit_creds(struct task_struct *tsk) { struct cred *cred; kdebug("exit_creds(%u,%p,%p,{%d,%d})", tsk->pid, tsk->real_cred, tsk->cred, atomic_read(&tsk->cred->usage), read_cred_subscribers(tsk->cred)); cred = (struct cred *) tsk->real_cred; tsk->real_cred = NULL; validate_creds(cred); alter_cred_subscribers(cred, -1); put_cred(cred); cred = (struct cred *) tsk->cred; tsk->cred = NULL; validate_creds(cred); alter_cred_subscribers(cred, -1); put_cred(cred); |
ee18d64c1
|
165 |
} |
de09a9771
|
166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 |
/** * get_task_cred - Get another task's objective credentials * @task: The task to query * * Get the objective credentials of a task, pinning them so that they can't go * away. Accessing a task's credentials directly is not permitted. * * The caller must also make sure task doesn't get deleted, either by holding a * ref on task or by holding tasklist_lock to prevent it from being unlinked. */ const struct cred *get_task_cred(struct task_struct *task) { const struct cred *cred; rcu_read_lock(); do { cred = __task_cred((task)); BUG_ON(!cred); } while (!atomic_inc_not_zero(&((struct cred *)cred)->usage)); rcu_read_unlock(); return cred; } |
ee18d64c1
|
190 191 192 193 194 195 196 197 198 199 200 |
/* * Allocate blank credentials, such that the credentials can be filled in at a * later date without risk of ENOMEM. */ struct cred *cred_alloc_blank(void) { struct cred *new; new = kmem_cache_zalloc(cred_jar, GFP_KERNEL); if (!new) return NULL; |
ee18d64c1
|
201 |
atomic_set(&new->usage, 1); |
2edeaa34a
|
202 203 204 |
#ifdef CONFIG_DEBUG_CREDENTIALS new->magic = CRED_MAGIC; #endif |
ee18d64c1
|
205 206 207 |
if (security_cred_alloc_blank(new, GFP_KERNEL) < 0) goto error; |
ee18d64c1
|
208 209 210 211 212 |
return new; error: abort_creds(new); return NULL; |
e0e817392
|
213 |
} |
d84f4f992
|
214 215 216 217 218 219 220 221 |
/** * prepare_creds - Prepare a new set of credentials for modification * * Prepare a new set of task credentials for modification. A task's creds * shouldn't generally be modified directly, therefore this function is used to * prepare a new copy, which the caller then modifies and then commits by * calling commit_creds(). * |
3b11a1dec
|
222 223 |
* Preparation involves making a copy of the objective creds for modification. * |
d84f4f992
|
224 225 226 227 228 229 230 231 232 |
* Returns a pointer to the new creds-to-be if successful, NULL otherwise. * * Call commit_creds() or abort_creds() to clean up. */ struct cred *prepare_creds(void) { struct task_struct *task = current; const struct cred *old; struct cred *new; |
e0e817392
|
233 |
validate_process_creds(); |
d84f4f992
|
234 235 236 237 |
new = kmem_cache_alloc(cred_jar, GFP_KERNEL); if (!new) return NULL; |
e0e817392
|
238 |
kdebug("prepare_creds() alloc %p", new); |
d84f4f992
|
239 240 241 242 |
old = task->cred; memcpy(new, old, sizeof(struct cred)); atomic_set(&new->usage, 1); |
e0e817392
|
243 |
set_cred_subscribers(new, 0); |
d84f4f992
|
244 245 |
get_group_info(new->group_info); get_uid(new->user); |
0093ccb68
|
246 |
get_user_ns(new->user_ns); |
d84f4f992
|
247 248 |
#ifdef CONFIG_KEYS |
3a50597de
|
249 250 |
key_get(new->session_keyring); key_get(new->process_keyring); |
d84f4f992
|
251 252 |
key_get(new->thread_keyring); key_get(new->request_key_auth); |
d84f4f992
|
253 254 255 256 257 258 259 260 |
#endif #ifdef CONFIG_SECURITY new->security = NULL; #endif if (security_prepare_creds(new, old, GFP_KERNEL) < 0) goto error; |
e0e817392
|
261 |
validate_creds(new); |
d84f4f992
|
262 263 264 265 266 267 268 269 270 |
return new; error: abort_creds(new); return NULL; } EXPORT_SYMBOL(prepare_creds); /* |
a6f76f23d
|
271 |
* Prepare credentials for current to perform an execve() |
9b1bf12d5
|
272 |
* - The caller must hold ->cred_guard_mutex |
a6f76f23d
|
273 274 275 |
*/ struct cred *prepare_exec_creds(void) { |
a6f76f23d
|
276 |
struct cred *new; |
a6f76f23d
|
277 |
new = prepare_creds(); |
3a50597de
|
278 |
if (!new) |
a6f76f23d
|
279 |
return new; |
a6f76f23d
|
280 281 282 283 284 |
#ifdef CONFIG_KEYS /* newly exec'd tasks don't get a thread keyring */ key_put(new->thread_keyring); new->thread_keyring = NULL; |
a6f76f23d
|
285 |
/* inherit the session keyring; new process keyring */ |
3a50597de
|
286 287 |
key_put(new->process_keyring); new->process_keyring = NULL; |
a6f76f23d
|
288 289 290 291 292 293 |
#endif return new; } /* |
f1752eec6
|
294 |
* Copy credentials for the new process created by fork() |
d84f4f992
|
295 296 297 |
* * We share if we can, but under some circumstances we have to generate a new * set. |
3b11a1dec
|
298 299 300 |
* * The new process gets the current process's subjective credentials as its * objective and subjective credentials |
f1752eec6
|
301 302 303 |
*/ int copy_creds(struct task_struct *p, unsigned long clone_flags) { |
d84f4f992
|
304 |
struct cred *new; |
18b6e0414
|
305 |
int ret; |
d84f4f992
|
306 |
|
d84f4f992
|
307 308 309 310 311 312 |
if ( #ifdef CONFIG_KEYS !p->cred->thread_keyring && #endif clone_flags & CLONE_THREAD ) { |
3b11a1dec
|
313 |
p->real_cred = get_cred(p->cred); |
d84f4f992
|
314 |
get_cred(p->cred); |
e0e817392
|
315 316 317 318 |
alter_cred_subscribers(p->cred, 2); kdebug("share_creds(%p{%d,%d})", p->cred, atomic_read(&p->cred->usage), read_cred_subscribers(p->cred)); |
d84f4f992
|
319 320 321 322 323 324 |
atomic_inc(&p->cred->user->processes); return 0; } new = prepare_creds(); if (!new) |
f1752eec6
|
325 |
return -ENOMEM; |
18b6e0414
|
326 327 328 329 330 |
if (clone_flags & CLONE_NEWUSER) { ret = create_user_ns(new); if (ret < 0) goto error_put; } |
bb952bb98
|
331 |
#ifdef CONFIG_KEYS |
d84f4f992
|
332 333 334 335 336 337 338 339 |
/* new threads get their own thread keyrings if their parent already * had one */ if (new->thread_keyring) { key_put(new->thread_keyring); new->thread_keyring = NULL; if (clone_flags & CLONE_THREAD) install_thread_keyring_to_cred(new); } |
3a50597de
|
340 341 342 |
/* The process keyring is only shared between the threads in a process; * anything outside of those threads doesn't inherit. */ |
d84f4f992
|
343 |
if (!(clone_flags & CLONE_THREAD)) { |
3a50597de
|
344 345 |
key_put(new->process_keyring); new->process_keyring = NULL; |
bb952bb98
|
346 347 |
} #endif |
d84f4f992
|
348 |
atomic_inc(&new->user->processes); |
3b11a1dec
|
349 |
p->cred = p->real_cred = get_cred(new); |
e0e817392
|
350 351 |
alter_cred_subscribers(new, 2); validate_creds(new); |
d84f4f992
|
352 |
return 0; |
18b6e0414
|
353 354 355 356 |
error_put: put_cred(new); return ret; |
d84f4f992
|
357 |
} |
f1752eec6
|
358 |
|
aa6d054e5
|
359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 |
static bool cred_cap_issubset(const struct cred *set, const struct cred *subset) { const struct user_namespace *set_ns = set->user_ns; const struct user_namespace *subset_ns = subset->user_ns; /* If the two credentials are in the same user namespace see if * the capabilities of subset are a subset of set. */ if (set_ns == subset_ns) return cap_issubset(subset->cap_permitted, set->cap_permitted); /* The credentials are in a different user namespaces * therefore one is a subset of the other only if a set is an * ancestor of subset and set->euid is owner of subset or one * of subsets ancestors. */ for (;subset_ns != &init_user_ns; subset_ns = subset_ns->parent) { if ((set_ns == subset_ns->parent) && uid_eq(subset_ns->owner, set->euid)) return true; } return false; } |
d84f4f992
|
383 384 385 386 387 |
/** * commit_creds - Install new credentials upon the current task * @new: The credentials to be assigned * * Install a new set of credentials to the current task, using RCU to replace |
3b11a1dec
|
388 389 390 |
* the old set. Both the objective and the subjective credentials pointers are * updated. This function may not be called if the subjective credentials are * in an overridden state. |
d84f4f992
|
391 392 393 394 395 396 397 398 399 |
* * This function eats the caller's reference to the new credentials. * * Always returns 0 thus allowing this function to be tail-called at the end * of, say, sys_setgid(). */ int commit_creds(struct cred *new) { struct task_struct *task = current; |
e0e817392
|
400 |
const struct cred *old = task->real_cred; |
d84f4f992
|
401 |
|
e0e817392
|
402 403 404 405 406 407 408 409 410 411 |
kdebug("commit_creds(%p{%d,%d})", new, atomic_read(&new->usage), read_cred_subscribers(new)); BUG_ON(task->cred != old); #ifdef CONFIG_DEBUG_CREDENTIALS BUG_ON(read_cred_subscribers(old) < 2); validate_creds(old); validate_creds(new); #endif |
d84f4f992
|
412 |
BUG_ON(atomic_read(&new->usage) < 1); |
d84f4f992
|
413 |
|
3b11a1dec
|
414 |
get_cred(new); /* we will require a ref for the subj creds too */ |
d84f4f992
|
415 |
/* dumpability changes */ |
078de5f70
|
416 417 418 419 |
if (!uid_eq(old->euid, new->euid) || !gid_eq(old->egid, new->egid) || !uid_eq(old->fsuid, new->fsuid) || !gid_eq(old->fsgid, new->fsgid) || |
aa6d054e5
|
420 |
!cred_cap_issubset(old, new)) { |
b9456371a
|
421 422 |
if (task->mm) set_dumpable(task->mm, suid_dumpable); |
d84f4f992
|
423 424 |
task->pdeath_signal = 0; smp_wmb(); |
f1752eec6
|
425 |
} |
d84f4f992
|
426 |
/* alter the thread keyring */ |
078de5f70
|
427 |
if (!uid_eq(new->fsuid, old->fsuid)) |
d84f4f992
|
428 |
key_fsuid_changed(task); |
078de5f70
|
429 |
if (!gid_eq(new->fsgid, old->fsgid)) |
d84f4f992
|
430 431 432 |
key_fsgid_changed(task); /* do it |
72fa59970
|
433 434 |
* RLIMIT_NPROC limits on user->processes have already been checked * in set_user(). |
d84f4f992
|
435 |
*/ |
e0e817392
|
436 |
alter_cred_subscribers(new, 2); |
d84f4f992
|
437 438 |
if (new->user != old->user) atomic_inc(&new->user->processes); |
3b11a1dec
|
439 |
rcu_assign_pointer(task->real_cred, new); |
d84f4f992
|
440 441 442 |
rcu_assign_pointer(task->cred, new); if (new->user != old->user) atomic_dec(&old->user->processes); |
e0e817392
|
443 |
alter_cred_subscribers(old, -2); |
d84f4f992
|
444 |
|
d84f4f992
|
445 |
/* send notifications */ |
078de5f70
|
446 447 448 449 |
if (!uid_eq(new->uid, old->uid) || !uid_eq(new->euid, old->euid) || !uid_eq(new->suid, old->suid) || !uid_eq(new->fsuid, old->fsuid)) |
d84f4f992
|
450 |
proc_id_connector(task, PROC_EVENT_UID); |
f1752eec6
|
451 |
|
078de5f70
|
452 453 454 455 |
if (!gid_eq(new->gid, old->gid) || !gid_eq(new->egid, old->egid) || !gid_eq(new->sgid, old->sgid) || !gid_eq(new->fsgid, old->fsgid)) |
d84f4f992
|
456 |
proc_id_connector(task, PROC_EVENT_GID); |
f1752eec6
|
457 |
|
3b11a1dec
|
458 459 |
/* release the old obj and subj refs both */ put_cred(old); |
d84f4f992
|
460 |
put_cred(old); |
f1752eec6
|
461 462 |
return 0; } |
d84f4f992
|
463 464 465 466 467 468 469 470 471 472 473 |
EXPORT_SYMBOL(commit_creds); /** * abort_creds - Discard a set of credentials and unlock the current task * @new: The credentials that were going to be applied * * Discard a set of credentials that were under construction and unlock the * current task. */ void abort_creds(struct cred *new) { |
e0e817392
|
474 475 476 477 478 479 480 |
kdebug("abort_creds(%p{%d,%d})", new, atomic_read(&new->usage), read_cred_subscribers(new)); #ifdef CONFIG_DEBUG_CREDENTIALS BUG_ON(read_cred_subscribers(new) != 0); #endif |
d84f4f992
|
481 482 483 484 485 486 |
BUG_ON(atomic_read(&new->usage) < 1); put_cred(new); } EXPORT_SYMBOL(abort_creds); /** |
3b11a1dec
|
487 |
* override_creds - Override the current process's subjective credentials |
d84f4f992
|
488 489 |
* @new: The credentials to be assigned * |
3b11a1dec
|
490 491 |
* Install a set of temporary override subjective credentials on the current * process, returning the old set for later reversion. |
d84f4f992
|
492 493 494 495 |
*/ const struct cred *override_creds(const struct cred *new) { const struct cred *old = current->cred; |
e0e817392
|
496 497 498 499 500 501 502 503 504 505 506 507 508 509 |
kdebug("override_creds(%p{%d,%d})", new, atomic_read(&new->usage), read_cred_subscribers(new)); validate_creds(old); validate_creds(new); get_cred(new); alter_cred_subscribers(new, 1); rcu_assign_pointer(current->cred, new); alter_cred_subscribers(old, -1); kdebug("override_creds() = %p{%d,%d}", old, atomic_read(&old->usage), read_cred_subscribers(old)); |
d84f4f992
|
510 511 512 513 514 |
return old; } EXPORT_SYMBOL(override_creds); /** |
3b11a1dec
|
515 |
* revert_creds - Revert a temporary subjective credentials override |
d84f4f992
|
516 517 |
* @old: The credentials to be restored * |
3b11a1dec
|
518 519 |
* Revert a temporary set of override subjective credentials to an old set, * discarding the override set. |
d84f4f992
|
520 521 522 523 |
*/ void revert_creds(const struct cred *old) { const struct cred *override = current->cred; |
e0e817392
|
524 525 526 527 528 529 530 |
kdebug("revert_creds(%p{%d,%d})", old, atomic_read(&old->usage), read_cred_subscribers(old)); validate_creds(old); validate_creds(override); alter_cred_subscribers(old, 1); |
d84f4f992
|
531 |
rcu_assign_pointer(current->cred, old); |
e0e817392
|
532 |
alter_cred_subscribers(override, -1); |
d84f4f992
|
533 534 535 536 537 538 539 540 541 542 543 544 545 |
put_cred(override); } EXPORT_SYMBOL(revert_creds); /* * initialise the credentials stuff */ void __init cred_init(void) { /* allocate a slab in which we can store credentials */ cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); } |
3a3b7ce93
|
546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 |
/** * prepare_kernel_cred - Prepare a set of credentials for a kernel service * @daemon: A userspace daemon to be used as a reference * * Prepare a set of credentials for a kernel service. This can then be used to * override a task's own credentials so that work can be done on behalf of that * task that requires a different subjective context. * * @daemon is used to provide a base for the security record, but can be NULL. * If @daemon is supplied, then the security data will be derived from that; * otherwise they'll be set to 0 and no groups, full capabilities and no keys. * * The caller may change these controls afterwards if desired. * * Returns the new credentials or NULL if out of memory. * * Does not take, and does not return holding current->cred_replace_mutex. */ struct cred *prepare_kernel_cred(struct task_struct *daemon) { const struct cred *old; struct cred *new; new = kmem_cache_alloc(cred_jar, GFP_KERNEL); if (!new) return NULL; |
e0e817392
|
573 |
kdebug("prepare_kernel_cred() alloc %p", new); |
3a3b7ce93
|
574 575 576 577 |
if (daemon) old = get_task_cred(daemon); else old = get_cred(&init_cred); |
e0e817392
|
578 |
validate_creds(old); |
43529c971
|
579 |
*new = *old; |
fb2b2a1d3
|
580 581 |
atomic_set(&new->usage, 1); set_cred_subscribers(new, 0); |
3a3b7ce93
|
582 |
get_uid(new->user); |
0093ccb68
|
583 |
get_user_ns(new->user_ns); |
3a3b7ce93
|
584 585 586 |
get_group_info(new->group_info); #ifdef CONFIG_KEYS |
3a50597de
|
587 588 |
new->session_keyring = NULL; new->process_keyring = NULL; |
3a3b7ce93
|
589 |
new->thread_keyring = NULL; |
3a50597de
|
590 |
new->request_key_auth = NULL; |
3a3b7ce93
|
591 592 593 594 595 596 597 598 |
new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING; #endif #ifdef CONFIG_SECURITY new->security = NULL; #endif if (security_prepare_creds(new, old, GFP_KERNEL) < 0) goto error; |
3a3b7ce93
|
599 |
put_cred(old); |
e0e817392
|
600 |
validate_creds(new); |
3a3b7ce93
|
601 602 603 604 |
return new; error: put_cred(new); |
0de336814
|
605 |
put_cred(old); |
3a3b7ce93
|
606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 |
return NULL; } EXPORT_SYMBOL(prepare_kernel_cred); /** * set_security_override - Set the security ID in a set of credentials * @new: The credentials to alter * @secid: The LSM security ID to set * * Set the LSM security ID in a set of credentials so that the subjective * security is overridden when an alternative set of credentials is used. */ int set_security_override(struct cred *new, u32 secid) { return security_kernel_act_as(new, secid); } EXPORT_SYMBOL(set_security_override); /** * set_security_override_from_ctx - Set the security ID in a set of credentials * @new: The credentials to alter * @secctx: The LSM security context to generate the security ID from. * * Set the LSM security ID in a set of credentials so that the subjective * security is overridden when an alternative set of credentials is used. The * security ID is specified in string form as a security context to be * interpreted by the LSM. */ int set_security_override_from_ctx(struct cred *new, const char *secctx) { u32 secid; int ret; ret = security_secctx_to_secid(secctx, strlen(secctx), &secid); if (ret < 0) return ret; return set_security_override(new, secid); } EXPORT_SYMBOL(set_security_override_from_ctx); /** * set_create_files_as - Set the LSM file create context in a set of credentials * @new: The credentials to alter * @inode: The inode to take the context from * * Change the LSM file creation context in a set of credentials to be the same * as the object context of the specified inode, so that the new inodes have * the same MAC context as that inode. */ int set_create_files_as(struct cred *new, struct inode *inode) { new->fsuid = inode->i_uid; new->fsgid = inode->i_gid; return security_kernel_create_files_as(new, inode); } EXPORT_SYMBOL(set_create_files_as); |
e0e817392
|
663 664 |
#ifdef CONFIG_DEBUG_CREDENTIALS |
74908a000
|
665 666 667 668 |
bool creds_are_invalid(const struct cred *cred) { if (cred->magic != CRED_MAGIC) return true; |
74908a000
|
669 |
#ifdef CONFIG_SECURITY_SELINUX |
2edeaa34a
|
670 671 672 673 674 |
/* * cred->security == NULL if security_cred_alloc_blank() or * security_prepare_creds() returned an error. */ if (selinux_is_enabled() && cred->security) { |
74908a000
|
675 676 677 678 679 680 681 682 683 |
if ((unsigned long) cred->security < PAGE_SIZE) return true; if ((*(u32 *)cred->security & 0xffffff00) == (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8)) return true; } #endif return false; } |
764db03fe
|
684 |
EXPORT_SYMBOL(creds_are_invalid); |
74908a000
|
685 |
|
e0e817392
|
686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 |
/* * dump invalid credentials */ static void dump_invalid_creds(const struct cred *cred, const char *label, const struct task_struct *tsk) { printk(KERN_ERR "CRED: %s credentials: %p %s%s%s ", label, cred, cred == &init_cred ? "[init]" : "", cred == tsk->real_cred ? "[real]" : "", cred == tsk->cred ? "[eff]" : ""); printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p ", cred->magic, cred->put_addr); printk(KERN_ERR "CRED: ->usage=%d, subscr=%d ", atomic_read(&cred->usage), read_cred_subscribers(cred)); printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d } ", |
c9235f487
|
707 708 709 710 |
from_kuid_munged(&init_user_ns, cred->uid), from_kuid_munged(&init_user_ns, cred->euid), from_kuid_munged(&init_user_ns, cred->suid), from_kuid_munged(&init_user_ns, cred->fsuid)); |
e0e817392
|
711 712 |
printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d } ", |
c9235f487
|
713 714 715 716 |
from_kgid_munged(&init_user_ns, cred->gid), from_kgid_munged(&init_user_ns, cred->egid), from_kgid_munged(&init_user_ns, cred->sgid), from_kgid_munged(&init_user_ns, cred->fsgid)); |
e0e817392
|
717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 |
#ifdef CONFIG_SECURITY printk(KERN_ERR "CRED: ->security is %p ", cred->security); if ((unsigned long) cred->security >= PAGE_SIZE && (((unsigned long) cred->security & 0xffffff00) != (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8))) printk(KERN_ERR "CRED: ->security {%x, %x} ", ((u32*)cred->security)[0], ((u32*)cred->security)[1]); #endif } /* * report use of invalid credentials */ void __invalid_creds(const struct cred *cred, const char *file, unsigned line) { printk(KERN_ERR "CRED: Invalid credentials "); printk(KERN_ERR "CRED: At %s:%u ", file, line); dump_invalid_creds(cred, "Specified", current); BUG(); } EXPORT_SYMBOL(__invalid_creds); /* * check the credentials on a process */ void __validate_process_creds(struct task_struct *tsk, const char *file, unsigned line) { if (tsk->cred == tsk->real_cred) { if (unlikely(read_cred_subscribers(tsk->cred) < 2 || creds_are_invalid(tsk->cred))) goto invalid_creds; } else { if (unlikely(read_cred_subscribers(tsk->real_cred) < 1 || read_cred_subscribers(tsk->cred) < 1 || creds_are_invalid(tsk->real_cred) || creds_are_invalid(tsk->cred))) goto invalid_creds; } return; invalid_creds: printk(KERN_ERR "CRED: Invalid process credentials "); printk(KERN_ERR "CRED: At %s:%u ", file, line); dump_invalid_creds(tsk->real_cred, "Real", tsk); if (tsk->cred != tsk->real_cred) dump_invalid_creds(tsk->cred, "Effective", tsk); else printk(KERN_ERR "CRED: Effective creds == Real creds "); BUG(); } EXPORT_SYMBOL(__validate_process_creds); /* * check creds for do_exit() */ void validate_creds_for_do_exit(struct task_struct *tsk) { kdebug("validate_creds_for_do_exit(%p,%p{%d,%d})", tsk->real_cred, tsk->cred, atomic_read(&tsk->cred->usage), read_cred_subscribers(tsk->cred)); __validate_process_creds(tsk, __FILE__, __LINE__); } #endif /* CONFIG_DEBUG_CREDENTIALS */ |