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