Blame view
kernel/cred.c
23.3 KB
b4d0d230c treewide: Replace... |
1 |
// SPDX-License-Identifier: GPL-2.0-or-later |
af777cd1b doc: ReSTify cred... |
2 |
/* Task credentials management - see Documentation/security/credentials.rst |
f1752eec6 CRED: Detach the ... |
3 4 5 |
* * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) |
f1752eec6 CRED: Detach the ... |
6 |
*/ |
9984de1a5 kernel: Map most ... |
7 |
#include <linux/export.h> |
f1752eec6 CRED: Detach the ... |
8 |
#include <linux/cred.h> |
5a0e3ad6a include cleanup: ... |
9 |
#include <linux/slab.h> |
f1752eec6 CRED: Detach the ... |
10 |
#include <linux/sched.h> |
f7ccbae45 sched/headers: Pr... |
11 |
#include <linux/sched/coredump.h> |
f1752eec6 CRED: Detach the ... |
12 13 14 15 |
#include <linux/key.h> #include <linux/keyctl.h> #include <linux/init_task.h> #include <linux/security.h> |
404015308 security: trim se... |
16 |
#include <linux/binfmts.h> |
d84f4f992 CRED: Inaugurate ... |
17 |
#include <linux/cn_proc.h> |
d89b22d46 cred: add cred_fs... |
18 |
#include <linux/uidgid.h> |
d84f4f992 CRED: Inaugurate ... |
19 |
|
e0e817392 CRED: Add some co... |
20 |
#if 0 |
52aa8536f kernel/cred.c: re... |
21 22 23 24 |
#define kdebug(FMT, ...) \ printk("[%-5.5s%5u] " FMT " ", \ current->comm, current->pid, ##__VA_ARGS__) |
e0e817392 CRED: Add some co... |
25 |
#else |
52aa8536f kernel/cred.c: re... |
26 27 28 29 30 31 32 |
#define kdebug(FMT, ...) \ do { \ if (0) \ no_printk("[%-5.5s%5u] " FMT " ", \ current->comm, current->pid, ##__VA_ARGS__); \ } while (0) |
e0e817392 CRED: Add some co... |
33 |
#endif |
d84f4f992 CRED: Inaugurate ... |
34 |
static struct kmem_cache *cred_jar; |
f1752eec6 CRED: Detach the ... |
35 |
|
2813893f8 kernel: condition... |
36 37 |
/* init to 2 - one for init_task, one to ensure it is never freed */ struct group_info init_groups = { .usage = ATOMIC_INIT(2) }; |
f1752eec6 CRED: Detach the ... |
38 39 40 41 |
/* * The initial credentials for the initial task */ struct cred init_cred = { |
3b11a1dec CRED: Differentia... |
42 |
.usage = ATOMIC_INIT(4), |
e0e817392 CRED: Add some co... |
43 44 45 46 |
#ifdef CONFIG_DEBUG_CREDENTIALS .subscribers = ATOMIC_INIT(2), .magic = CRED_MAGIC, #endif |
078de5f70 userns: Store uid... |
47 48 49 50 51 52 53 54 |
.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 CRED: Detach the ... |
55 |
.securebits = SECUREBITS_DEFAULT, |
a3232d2fa capabilities: del... |
56 |
.cap_inheritable = CAP_EMPTY_SET, |
f1752eec6 CRED: Detach the ... |
57 |
.cap_permitted = CAP_FULL_SET, |
a3232d2fa capabilities: del... |
58 59 |
.cap_effective = CAP_FULL_SET, .cap_bset = CAP_FULL_SET, |
f1752eec6 CRED: Detach the ... |
60 |
.user = INIT_USER, |
47a150edc Cache user_ns in ... |
61 |
.user_ns = &init_user_ns, |
f1752eec6 CRED: Detach the ... |
62 63 |
.group_info = &init_groups, }; |
e0e817392 CRED: Add some co... |
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 |
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 CRED: Detach the ... |
88 89 90 91 92 93 |
/* * 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 CRED: Add some co... |
94 95 96 97 98 99 100 101 102 103 104 105 106 |
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 CRED: Inaugurate ... |
107 108 109 110 |
if (atomic_read(&cred->usage) != 0) panic("CRED: put_cred_rcu() sees %p with usage %d ", cred, atomic_read(&cred->usage)); |
e0e817392 CRED: Add some co... |
111 |
#endif |
f1752eec6 CRED: Detach the ... |
112 |
|
d84f4f992 CRED: Inaugurate ... |
113 |
security_cred_free(cred); |
3a50597de KEYS: Make the se... |
114 115 |
key_put(cred->session_keyring); key_put(cred->process_keyring); |
f1752eec6 CRED: Detach the ... |
116 117 |
key_put(cred->thread_keyring); key_put(cred->request_key_auth); |
4a5d6ba19 CRED: Allow put_c... |
118 119 |
if (cred->group_info) put_group_info(cred->group_info); |
f1752eec6 CRED: Detach the ... |
120 |
free_uid(cred->user); |
0093ccb68 cred: Refcount th... |
121 |
put_user_ns(cred->user_ns); |
d84f4f992 CRED: Inaugurate ... |
122 |
kmem_cache_free(cred_jar, cred); |
f1752eec6 CRED: Detach the ... |
123 124 125 126 |
} /** * __put_cred - Destroy a set of credentials |
d84f4f992 CRED: Inaugurate ... |
127 |
* @cred: The record to release |
f1752eec6 CRED: Detach the ... |
128 129 130 131 132 |
* * Destroy a set of credentials on which no references remain. */ void __put_cred(struct cred *cred) { |
e0e817392 CRED: Add some co... |
133 134 135 |
kdebug("__put_cred(%p{%d,%d})", cred, atomic_read(&cred->usage), read_cred_subscribers(cred)); |
d84f4f992 CRED: Inaugurate ... |
136 |
BUG_ON(atomic_read(&cred->usage) != 0); |
e0e817392 CRED: Add some co... |
137 138 139 140 141 142 143 |
#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 CRED: Inaugurate ... |
144 |
|
d7852fbd0 access: avoid the... |
145 146 147 148 |
if (cred->non_rcu) put_cred_rcu(&cred->rcu); else call_rcu(&cred->rcu, put_cred_rcu); |
f1752eec6 CRED: Detach the ... |
149 150 |
} EXPORT_SYMBOL(__put_cred); |
e0e817392 CRED: Add some co... |
151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 |
/* * 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); |
7743c48e5 keys: Cache resul... |
173 174 |
#ifdef CONFIG_KEYS_REQUEST_CACHE |
8379bb84b keys: Fix request... |
175 176 |
key_put(tsk->cached_requested_key); tsk->cached_requested_key = NULL; |
7743c48e5 keys: Cache resul... |
177 |
#endif |
ee18d64c1 KEYS: Add a keyct... |
178 |
} |
de09a9771 CRED: Fix get_tas... |
179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 |
/** * 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); |
97d0fb239 cred: add get_cre... |
198 |
} while (!get_cred_rcu(cred)); |
de09a9771 CRED: Fix get_tas... |
199 200 201 202 |
rcu_read_unlock(); return cred; } |
a6d8e7637 cred: export get_... |
203 |
EXPORT_SYMBOL(get_task_cred); |
de09a9771 CRED: Fix get_tas... |
204 |
|
ee18d64c1 KEYS: Add a keyct... |
205 206 207 208 209 210 211 212 213 214 215 |
/* * 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 KEYS: Add a keyct... |
216 |
atomic_set(&new->usage, 1); |
2edeaa34a CRED: Fix BUG() u... |
217 218 219 |
#ifdef CONFIG_DEBUG_CREDENTIALS new->magic = CRED_MAGIC; #endif |
ee18d64c1 KEYS: Add a keyct... |
220 |
|
84029fd04 memcg: account se... |
221 |
if (security_cred_alloc_blank(new, GFP_KERNEL_ACCOUNT) < 0) |
ee18d64c1 KEYS: Add a keyct... |
222 |
goto error; |
ee18d64c1 KEYS: Add a keyct... |
223 224 225 226 227 |
return new; error: abort_creds(new); return NULL; |
e0e817392 CRED: Add some co... |
228 |
} |
d84f4f992 CRED: Inaugurate ... |
229 230 231 232 233 234 235 236 |
/** * 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 CRED: Differentia... |
237 238 |
* Preparation involves making a copy of the objective creds for modification. * |
d84f4f992 CRED: Inaugurate ... |
239 240 241 242 243 244 245 246 247 |
* 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 CRED: Add some co... |
248 |
validate_process_creds(); |
d84f4f992 CRED: Inaugurate ... |
249 250 251 252 |
new = kmem_cache_alloc(cred_jar, GFP_KERNEL); if (!new) return NULL; |
e0e817392 CRED: Add some co... |
253 |
kdebug("prepare_creds() alloc %p", new); |
d84f4f992 CRED: Inaugurate ... |
254 255 |
old = task->cred; memcpy(new, old, sizeof(struct cred)); |
d7852fbd0 access: avoid the... |
256 |
new->non_rcu = 0; |
d84f4f992 CRED: Inaugurate ... |
257 |
atomic_set(&new->usage, 1); |
e0e817392 CRED: Add some co... |
258 |
set_cred_subscribers(new, 0); |
d84f4f992 CRED: Inaugurate ... |
259 260 |
get_group_info(new->group_info); get_uid(new->user); |
0093ccb68 cred: Refcount th... |
261 |
get_user_ns(new->user_ns); |
d84f4f992 CRED: Inaugurate ... |
262 263 |
#ifdef CONFIG_KEYS |
3a50597de KEYS: Make the se... |
264 265 |
key_get(new->session_keyring); key_get(new->process_keyring); |
d84f4f992 CRED: Inaugurate ... |
266 267 |
key_get(new->thread_keyring); key_get(new->request_key_auth); |
d84f4f992 CRED: Inaugurate ... |
268 269 270 271 272 |
#endif #ifdef CONFIG_SECURITY new->security = NULL; #endif |
84029fd04 memcg: account se... |
273 |
if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0) |
d84f4f992 CRED: Inaugurate ... |
274 |
goto error; |
e0e817392 CRED: Add some co... |
275 |
validate_creds(new); |
d84f4f992 CRED: Inaugurate ... |
276 277 278 279 280 281 282 283 284 |
return new; error: abort_creds(new); return NULL; } EXPORT_SYMBOL(prepare_creds); /* |
a6f76f23d CRED: Make execve... |
285 |
* Prepare credentials for current to perform an execve() |
9b1bf12d5 signals: move cre... |
286 |
* - The caller must hold ->cred_guard_mutex |
a6f76f23d CRED: Make execve... |
287 288 289 |
*/ struct cred *prepare_exec_creds(void) { |
a6f76f23d CRED: Make execve... |
290 |
struct cred *new; |
a6f76f23d CRED: Make execve... |
291 |
new = prepare_creds(); |
3a50597de KEYS: Make the se... |
292 |
if (!new) |
a6f76f23d CRED: Make execve... |
293 |
return new; |
a6f76f23d CRED: Make execve... |
294 295 296 297 298 |
#ifdef CONFIG_KEYS /* newly exec'd tasks don't get a thread keyring */ key_put(new->thread_keyring); new->thread_keyring = NULL; |
a6f76f23d CRED: Make execve... |
299 |
/* inherit the session keyring; new process keyring */ |
3a50597de KEYS: Make the se... |
300 301 |
key_put(new->process_keyring); new->process_keyring = NULL; |
a6f76f23d CRED: Make execve... |
302 |
#endif |
87b047d2b exec: Teach prepa... |
303 304 |
new->suid = new->fsuid = new->euid; new->sgid = new->fsgid = new->egid; |
a6f76f23d CRED: Make execve... |
305 306 307 308 |
return new; } /* |
f1752eec6 CRED: Detach the ... |
309 |
* Copy credentials for the new process created by fork() |
d84f4f992 CRED: Inaugurate ... |
310 311 312 |
* * We share if we can, but under some circumstances we have to generate a new * set. |
3b11a1dec CRED: Differentia... |
313 314 315 |
* * The new process gets the current process's subjective credentials as its * objective and subjective credentials |
f1752eec6 CRED: Detach the ... |
316 317 318 |
*/ int copy_creds(struct task_struct *p, unsigned long clone_flags) { |
d84f4f992 CRED: Inaugurate ... |
319 |
struct cred *new; |
18b6e0414 User namespaces: ... |
320 |
int ret; |
d84f4f992 CRED: Inaugurate ... |
321 |
|
7743c48e5 keys: Cache resul... |
322 323 324 |
#ifdef CONFIG_KEYS_REQUEST_CACHE p->cached_requested_key = NULL; #endif |
d84f4f992 CRED: Inaugurate ... |
325 326 327 328 329 330 |
if ( #ifdef CONFIG_KEYS !p->cred->thread_keyring && #endif clone_flags & CLONE_THREAD ) { |
3b11a1dec CRED: Differentia... |
331 |
p->real_cred = get_cred(p->cred); |
d84f4f992 CRED: Inaugurate ... |
332 |
get_cred(p->cred); |
e0e817392 CRED: Add some co... |
333 334 335 336 |
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 CRED: Inaugurate ... |
337 338 339 340 341 342 |
atomic_inc(&p->cred->user->processes); return 0; } new = prepare_creds(); if (!new) |
f1752eec6 CRED: Detach the ... |
343 |
return -ENOMEM; |
18b6e0414 User namespaces: ... |
344 345 346 347 348 |
if (clone_flags & CLONE_NEWUSER) { ret = create_user_ns(new); if (ret < 0) goto error_put; } |
bb952bb98 CRED: Separate pe... |
349 |
#ifdef CONFIG_KEYS |
d84f4f992 CRED: Inaugurate ... |
350 351 352 353 354 355 356 357 |
/* 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 KEYS: Make the se... |
358 359 360 |
/* The process keyring is only shared between the threads in a process; * anything outside of those threads doesn't inherit. */ |
d84f4f992 CRED: Inaugurate ... |
361 |
if (!(clone_flags & CLONE_THREAD)) { |
3a50597de KEYS: Make the se... |
362 363 |
key_put(new->process_keyring); new->process_keyring = NULL; |
bb952bb98 CRED: Separate pe... |
364 365 |
} #endif |
d84f4f992 CRED: Inaugurate ... |
366 |
atomic_inc(&new->user->processes); |
3b11a1dec CRED: Differentia... |
367 |
p->cred = p->real_cred = get_cred(new); |
e0e817392 CRED: Add some co... |
368 369 |
alter_cred_subscribers(new, 2); validate_creds(new); |
d84f4f992 CRED: Inaugurate ... |
370 |
return 0; |
18b6e0414 User namespaces: ... |
371 372 373 374 |
error_put: put_cred(new); return ret; |
d84f4f992 CRED: Inaugurate ... |
375 |
} |
f1752eec6 CRED: Detach the ... |
376 |
|
aa6d054e5 userns: Add a mor... |
377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 |
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 CRED: Inaugurate ... |
401 402 403 404 405 |
/** * 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 CRED: Differentia... |
406 407 408 |
* 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 CRED: Inaugurate ... |
409 410 411 412 413 414 415 416 417 |
* * 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 CRED: Add some co... |
418 |
const struct cred *old = task->real_cred; |
d84f4f992 CRED: Inaugurate ... |
419 |
|
e0e817392 CRED: Add some co... |
420 421 422 423 424 425 426 427 428 429 |
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 CRED: Inaugurate ... |
430 |
BUG_ON(atomic_read(&new->usage) < 1); |
d84f4f992 CRED: Inaugurate ... |
431 |
|
3b11a1dec CRED: Differentia... |
432 |
get_cred(new); /* we will require a ref for the subj creds too */ |
d84f4f992 CRED: Inaugurate ... |
433 |
/* dumpability changes */ |
078de5f70 userns: Store uid... |
434 435 436 437 |
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 userns: Add a mor... |
438 |
!cred_cap_issubset(old, new)) { |
b9456371a CRED: Fix commit_... |
439 440 |
if (task->mm) set_dumpable(task->mm, suid_dumpable); |
d84f4f992 CRED: Inaugurate ... |
441 |
task->pdeath_signal = 0; |
f6581f5b5 ptrace: restore s... |
442 443 444 445 446 447 448 449 450 |
/* * If a task drops privileges and becomes nondumpable, * the dumpability change must become visible before * the credential change; otherwise, a __ptrace_may_access() * racing with this change may be able to attach to a task it * shouldn't be able to attach to (as if the task had dropped * privileges without becoming nondumpable). * Pairs with a read barrier in __ptrace_may_access(). */ |
d84f4f992 CRED: Inaugurate ... |
451 |
smp_wmb(); |
f1752eec6 CRED: Detach the ... |
452 |
} |
d84f4f992 CRED: Inaugurate ... |
453 |
/* alter the thread keyring */ |
078de5f70 userns: Store uid... |
454 |
if (!uid_eq(new->fsuid, old->fsuid)) |
2e21865fa keys: sparse: Fix... |
455 |
key_fsuid_changed(new); |
078de5f70 userns: Store uid... |
456 |
if (!gid_eq(new->fsgid, old->fsgid)) |
2e21865fa keys: sparse: Fix... |
457 |
key_fsgid_changed(new); |
d84f4f992 CRED: Inaugurate ... |
458 459 |
/* do it |
72fa59970 move RLIMIT_NPROC... |
460 461 |
* RLIMIT_NPROC limits on user->processes have already been checked * in set_user(). |
d84f4f992 CRED: Inaugurate ... |
462 |
*/ |
e0e817392 CRED: Add some co... |
463 |
alter_cred_subscribers(new, 2); |
d84f4f992 CRED: Inaugurate ... |
464 465 |
if (new->user != old->user) atomic_inc(&new->user->processes); |
3b11a1dec CRED: Differentia... |
466 |
rcu_assign_pointer(task->real_cred, new); |
d84f4f992 CRED: Inaugurate ... |
467 468 469 |
rcu_assign_pointer(task->cred, new); if (new->user != old->user) atomic_dec(&old->user->processes); |
e0e817392 CRED: Add some co... |
470 |
alter_cred_subscribers(old, -2); |
d84f4f992 CRED: Inaugurate ... |
471 |
|
d84f4f992 CRED: Inaugurate ... |
472 |
/* send notifications */ |
078de5f70 userns: Store uid... |
473 474 475 476 |
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 CRED: Inaugurate ... |
477 |
proc_id_connector(task, PROC_EVENT_UID); |
f1752eec6 CRED: Detach the ... |
478 |
|
078de5f70 userns: Store uid... |
479 480 481 482 |
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 CRED: Inaugurate ... |
483 |
proc_id_connector(task, PROC_EVENT_GID); |
f1752eec6 CRED: Detach the ... |
484 |
|
3b11a1dec CRED: Differentia... |
485 486 |
/* release the old obj and subj refs both */ put_cred(old); |
d84f4f992 CRED: Inaugurate ... |
487 |
put_cred(old); |
f1752eec6 CRED: Detach the ... |
488 489 |
return 0; } |
d84f4f992 CRED: Inaugurate ... |
490 491 492 493 494 495 496 497 498 499 500 |
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 CRED: Add some co... |
501 502 503 504 505 506 507 |
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 CRED: Inaugurate ... |
508 509 510 511 512 513 |
BUG_ON(atomic_read(&new->usage) < 1); put_cred(new); } EXPORT_SYMBOL(abort_creds); /** |
3b11a1dec CRED: Differentia... |
514 |
* override_creds - Override the current process's subjective credentials |
d84f4f992 CRED: Inaugurate ... |
515 516 |
* @new: The credentials to be assigned * |
3b11a1dec CRED: Differentia... |
517 518 |
* Install a set of temporary override subjective credentials on the current * process, returning the old set for later reversion. |
d84f4f992 CRED: Inaugurate ... |
519 520 521 522 |
*/ const struct cred *override_creds(const struct cred *new) { const struct cred *old = current->cred; |
e0e817392 CRED: Add some co... |
523 524 525 526 527 528 |
kdebug("override_creds(%p{%d,%d})", new, atomic_read(&new->usage), read_cred_subscribers(new)); validate_creds(old); validate_creds(new); |
d7852fbd0 access: avoid the... |
529 530 531 532 533 534 535 536 537 538 539 540 541 |
/* * NOTE! This uses 'get_new_cred()' rather than 'get_cred()'. * * That means that we do not clear the 'non_rcu' flag, since * we are only installing the cred into the thread-synchronous * '->cred' pointer, not the '->real_cred' pointer that is * visible to other threads under RCU. * * Also note that we did validate_creds() manually, not depending * on the validation in 'get_cred()'. */ get_new_cred((struct cred *)new); |
e0e817392 CRED: Add some co... |
542 543 544 545 546 547 548 |
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 CRED: Inaugurate ... |
549 550 551 552 553 |
return old; } EXPORT_SYMBOL(override_creds); /** |
3b11a1dec CRED: Differentia... |
554 |
* revert_creds - Revert a temporary subjective credentials override |
d84f4f992 CRED: Inaugurate ... |
555 556 |
* @old: The credentials to be restored * |
3b11a1dec CRED: Differentia... |
557 558 |
* Revert a temporary set of override subjective credentials to an old set, * discarding the override set. |
d84f4f992 CRED: Inaugurate ... |
559 560 561 562 |
*/ void revert_creds(const struct cred *old) { const struct cred *override = current->cred; |
e0e817392 CRED: Add some co... |
563 564 565 566 567 568 569 |
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 CRED: Inaugurate ... |
570 |
rcu_assign_pointer(current->cred, old); |
e0e817392 CRED: Add some co... |
571 |
alter_cred_subscribers(override, -1); |
d84f4f992 CRED: Inaugurate ... |
572 573 574 |
put_cred(override); } EXPORT_SYMBOL(revert_creds); |
d89b22d46 cred: add cred_fs... |
575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 |
/** * cred_fscmp - Compare two credentials with respect to filesystem access. * @a: The first credential * @b: The second credential * * cred_cmp() will return zero if both credentials have the same * fsuid, fsgid, and supplementary groups. That is, if they will both * provide the same access to files based on mode/uid/gid. * If the credentials are different, then either -1 or 1 will * be returned depending on whether @a comes before or after @b * respectively in an arbitrary, but stable, ordering of credentials. * * Return: -1, 0, or 1 depending on comparison */ int cred_fscmp(const struct cred *a, const struct cred *b) { struct group_info *ga, *gb; int g; if (a == b) return 0; if (uid_lt(a->fsuid, b->fsuid)) return -1; if (uid_gt(a->fsuid, b->fsuid)) return 1; if (gid_lt(a->fsgid, b->fsgid)) return -1; if (gid_gt(a->fsgid, b->fsgid)) return 1; ga = a->group_info; gb = b->group_info; if (ga == gb) return 0; if (ga == NULL) return -1; if (gb == NULL) return 1; if (ga->ngroups < gb->ngroups) return -1; if (ga->ngroups > gb->ngroups) return 1; for (g = 0; g < ga->ngroups; g++) { if (gid_lt(ga->gid[g], gb->gid[g])) return -1; if (gid_gt(ga->gid[g], gb->gid[g])) return 1; } return 0; } EXPORT_SYMBOL(cred_fscmp); |
d84f4f992 CRED: Inaugurate ... |
628 629 630 631 632 633 |
/* * initialise the credentials stuff */ void __init cred_init(void) { /* allocate a slab in which we can store credentials */ |
5d097056c kmemcg: account c... |
634 635 |
cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); |
d84f4f992 CRED: Inaugurate ... |
636 |
} |
3a3b7ce93 CRED: Allow kerne... |
637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 |
/** * 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. |
3a3b7ce93 CRED: Allow kerne... |
653 654 655 656 657 658 659 660 661 |
*/ 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 CRED: Add some co... |
662 |
kdebug("prepare_kernel_cred() alloc %p", new); |
3a3b7ce93 CRED: Allow kerne... |
663 664 665 666 |
if (daemon) old = get_task_cred(daemon); else old = get_cred(&init_cred); |
e0e817392 CRED: Add some co... |
667 |
validate_creds(old); |
43529c971 CRED: Must initia... |
668 |
*new = *old; |
d7852fbd0 access: avoid the... |
669 |
new->non_rcu = 0; |
fb2b2a1d3 CRED: Fix memory ... |
670 671 |
atomic_set(&new->usage, 1); set_cred_subscribers(new, 0); |
3a3b7ce93 CRED: Allow kerne... |
672 |
get_uid(new->user); |
0093ccb68 cred: Refcount th... |
673 |
get_user_ns(new->user_ns); |
3a3b7ce93 CRED: Allow kerne... |
674 675 676 |
get_group_info(new->group_info); #ifdef CONFIG_KEYS |
3a50597de KEYS: Make the se... |
677 678 |
new->session_keyring = NULL; new->process_keyring = NULL; |
3a3b7ce93 CRED: Allow kerne... |
679 |
new->thread_keyring = NULL; |
3a50597de KEYS: Make the se... |
680 |
new->request_key_auth = NULL; |
3a3b7ce93 CRED: Allow kerne... |
681 682 683 684 685 686 |
new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING; #endif #ifdef CONFIG_SECURITY new->security = NULL; #endif |
84029fd04 memcg: account se... |
687 |
if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0) |
3a3b7ce93 CRED: Allow kerne... |
688 |
goto error; |
3a3b7ce93 CRED: Allow kerne... |
689 |
put_cred(old); |
e0e817392 CRED: Add some co... |
690 |
validate_creds(new); |
3a3b7ce93 CRED: Allow kerne... |
691 692 693 694 |
return new; error: put_cred(new); |
0de336814 CRED: Missing put... |
695 |
put_cred(old); |
3a3b7ce93 CRED: Allow kerne... |
696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 |
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) { |
5f65e5ca2 cred: Reject inod... |
748 749 |
if (!uid_valid(inode->i_uid) || !gid_valid(inode->i_gid)) return -EINVAL; |
3a3b7ce93 CRED: Allow kerne... |
750 751 752 753 754 |
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 CRED: Add some co... |
755 756 |
#ifdef CONFIG_DEBUG_CREDENTIALS |
74908a000 include/linux/cre... |
757 758 759 760 |
bool creds_are_invalid(const struct cred *cred) { if (cred->magic != CRED_MAGIC) return true; |
74908a000 include/linux/cre... |
761 762 |
return false; } |
764db03fe creds_are_invalid... |
763 |
EXPORT_SYMBOL(creds_are_invalid); |
74908a000 include/linux/cre... |
764 |
|
e0e817392 CRED: Add some co... |
765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 |
/* * 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 userns: Make cred... |
786 787 788 789 |
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 CRED: Add some co... |
790 791 |
printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d } ", |
c9235f487 userns: Make cred... |
792 793 794 795 |
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 CRED: Add some co... |
796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 |
#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 */ |