perf: net_dropmonitor: Fix symbol-relative addresses
[linux-3.10.git] / kernel / cred.c
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 static bool cred_cap_issubset(const struct cred *set, const struct cred *subset)
376 {
377         const struct user_namespace *set_ns = set->user_ns;
378         const struct user_namespace *subset_ns = subset->user_ns;
379
380         /* If the two credentials are in the same user namespace see if
381          * the capabilities of subset are a subset of set.
382          */
383         if (set_ns == subset_ns)
384                 return cap_issubset(subset->cap_permitted, set->cap_permitted);
385
386         /* The credentials are in a different user namespaces
387          * therefore one is a subset of the other only if a set is an
388          * ancestor of subset and set->euid is owner of subset or one
389          * of subsets ancestors.
390          */
391         for (;subset_ns != &init_user_ns; subset_ns = subset_ns->parent) {
392                 if ((set_ns == subset_ns->parent)  &&
393                     uid_eq(subset_ns->owner, set->euid))
394                         return true;
395         }
396
397         return false;
398 }
399
400 /**
401  * commit_creds - Install new credentials upon the current task
402  * @new: The credentials to be assigned
403  *
404  * Install a new set of credentials to the current task, using RCU to replace
405  * the old set.  Both the objective and the subjective credentials pointers are
406  * updated.  This function may not be called if the subjective credentials are
407  * in an overridden state.
408  *
409  * This function eats the caller's reference to the new credentials.
410  *
411  * Always returns 0 thus allowing this function to be tail-called at the end
412  * of, say, sys_setgid().
413  */
414 int commit_creds(struct cred *new)
415 {
416         struct task_struct *task = current;
417         const struct cred *old = task->real_cred;
418
419         kdebug("commit_creds(%p{%d,%d})", new,
420                atomic_read(&new->usage),
421                read_cred_subscribers(new));
422
423         BUG_ON(task->cred != old);
424 #ifdef CONFIG_DEBUG_CREDENTIALS
425         BUG_ON(read_cred_subscribers(old) < 2);
426         validate_creds(old);
427         validate_creds(new);
428 #endif
429         BUG_ON(atomic_read(&new->usage) < 1);
430
431         get_cred(new); /* we will require a ref for the subj creds too */
432
433         /* dumpability changes */
434         if (!uid_eq(old->euid, new->euid) ||
435             !gid_eq(old->egid, new->egid) ||
436             !uid_eq(old->fsuid, new->fsuid) ||
437             !gid_eq(old->fsgid, new->fsgid) ||
438             !cred_cap_issubset(old, new)) {
439                 if (task->mm)
440                         set_dumpable(task->mm, suid_dumpable);
441                 task->pdeath_signal = 0;
442                 smp_wmb();
443         }
444
445         /* alter the thread keyring */
446         if (!uid_eq(new->fsuid, old->fsuid))
447                 key_fsuid_changed(task);
448         if (!gid_eq(new->fsgid, old->fsgid))
449                 key_fsgid_changed(task);
450
451         /* do it
452          * RLIMIT_NPROC limits on user->processes have already been checked
453          * in set_user().
454          */
455         alter_cred_subscribers(new, 2);
456         if (new->user != old->user)
457                 atomic_inc(&new->user->processes);
458         rcu_assign_pointer(task->real_cred, new);
459         rcu_assign_pointer(task->cred, new);
460         if (new->user != old->user)
461                 atomic_dec(&old->user->processes);
462         alter_cred_subscribers(old, -2);
463
464         /* send notifications */
465         if (!uid_eq(new->uid,   old->uid)  ||
466             !uid_eq(new->euid,  old->euid) ||
467             !uid_eq(new->suid,  old->suid) ||
468             !uid_eq(new->fsuid, old->fsuid))
469                 proc_id_connector(task, PROC_EVENT_UID);
470
471         if (!gid_eq(new->gid,   old->gid)  ||
472             !gid_eq(new->egid,  old->egid) ||
473             !gid_eq(new->sgid,  old->sgid) ||
474             !gid_eq(new->fsgid, old->fsgid))
475                 proc_id_connector(task, PROC_EVENT_GID);
476
477         /* release the old obj and subj refs both */
478         put_cred(old);
479         put_cred(old);
480         return 0;
481 }
482 EXPORT_SYMBOL(commit_creds);
483
484 /**
485  * abort_creds - Discard a set of credentials and unlock the current task
486  * @new: The credentials that were going to be applied
487  *
488  * Discard a set of credentials that were under construction and unlock the
489  * current task.
490  */
491 void abort_creds(struct cred *new)
492 {
493         kdebug("abort_creds(%p{%d,%d})", new,
494                atomic_read(&new->usage),
495                read_cred_subscribers(new));
496
497 #ifdef CONFIG_DEBUG_CREDENTIALS
498         BUG_ON(read_cred_subscribers(new) != 0);
499 #endif
500         BUG_ON(atomic_read(&new->usage) < 1);
501         put_cred(new);
502 }
503 EXPORT_SYMBOL(abort_creds);
504
505 /**
506  * override_creds - Override the current process's subjective credentials
507  * @new: The credentials to be assigned
508  *
509  * Install a set of temporary override subjective credentials on the current
510  * process, returning the old set for later reversion.
511  */
512 const struct cred *override_creds(const struct cred *new)
513 {
514         const struct cred *old = current->cred;
515
516         kdebug("override_creds(%p{%d,%d})", new,
517                atomic_read(&new->usage),
518                read_cred_subscribers(new));
519
520         validate_creds(old);
521         validate_creds(new);
522         get_cred(new);
523         alter_cred_subscribers(new, 1);
524         rcu_assign_pointer(current->cred, new);
525         alter_cred_subscribers(old, -1);
526
527         kdebug("override_creds() = %p{%d,%d}", old,
528                atomic_read(&old->usage),
529                read_cred_subscribers(old));
530         return old;
531 }
532 EXPORT_SYMBOL(override_creds);
533
534 /**
535  * revert_creds - Revert a temporary subjective credentials override
536  * @old: The credentials to be restored
537  *
538  * Revert a temporary set of override subjective credentials to an old set,
539  * discarding the override set.
540  */
541 void revert_creds(const struct cred *old)
542 {
543         const struct cred *override = current->cred;
544
545         kdebug("revert_creds(%p{%d,%d})", old,
546                atomic_read(&old->usage),
547                read_cred_subscribers(old));
548
549         validate_creds(old);
550         validate_creds(override);
551         alter_cred_subscribers(old, 1);
552         rcu_assign_pointer(current->cred, old);
553         alter_cred_subscribers(override, -1);
554         put_cred(override);
555 }
556 EXPORT_SYMBOL(revert_creds);
557
558 /*
559  * initialise the credentials stuff
560  */
561 void __init cred_init(void)
562 {
563         /* allocate a slab in which we can store credentials */
564         cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred),
565                                      0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
566 }
567
568 /**
569  * prepare_kernel_cred - Prepare a set of credentials for a kernel service
570  * @daemon: A userspace daemon to be used as a reference
571  *
572  * Prepare a set of credentials for a kernel service.  This can then be used to
573  * override a task's own credentials so that work can be done on behalf of that
574  * task that requires a different subjective context.
575  *
576  * @daemon is used to provide a base for the security record, but can be NULL.
577  * If @daemon is supplied, then the security data will be derived from that;
578  * otherwise they'll be set to 0 and no groups, full capabilities and no keys.
579  *
580  * The caller may change these controls afterwards if desired.
581  *
582  * Returns the new credentials or NULL if out of memory.
583  *
584  * Does not take, and does not return holding current->cred_replace_mutex.
585  */
586 struct cred *prepare_kernel_cred(struct task_struct *daemon)
587 {
588         const struct cred *old;
589         struct cred *new;
590
591         new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
592         if (!new)
593                 return NULL;
594
595         kdebug("prepare_kernel_cred() alloc %p", new);
596
597         if (daemon)
598                 old = get_task_cred(daemon);
599         else
600                 old = get_cred(&init_cred);
601
602         validate_creds(old);
603
604         *new = *old;
605         atomic_set(&new->usage, 1);
606         set_cred_subscribers(new, 0);
607         get_uid(new->user);
608         get_user_ns(new->user_ns);
609         get_group_info(new->group_info);
610
611 #ifdef CONFIG_KEYS
612         new->session_keyring = NULL;
613         new->process_keyring = NULL;
614         new->thread_keyring = NULL;
615         new->request_key_auth = NULL;
616         new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
617 #endif
618
619 #ifdef CONFIG_SECURITY
620         new->security = NULL;
621 #endif
622         if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
623                 goto error;
624
625         put_cred(old);
626         validate_creds(new);
627         return new;
628
629 error:
630         put_cred(new);
631         put_cred(old);
632         return NULL;
633 }
634 EXPORT_SYMBOL(prepare_kernel_cred);
635
636 /**
637  * set_security_override - Set the security ID in a set of credentials
638  * @new: The credentials to alter
639  * @secid: The LSM security ID to set
640  *
641  * Set the LSM security ID in a set of credentials so that the subjective
642  * security is overridden when an alternative set of credentials is used.
643  */
644 int set_security_override(struct cred *new, u32 secid)
645 {
646         return security_kernel_act_as(new, secid);
647 }
648 EXPORT_SYMBOL(set_security_override);
649
650 /**
651  * set_security_override_from_ctx - Set the security ID in a set of credentials
652  * @new: The credentials to alter
653  * @secctx: The LSM security context to generate the security ID from.
654  *
655  * Set the LSM security ID in a set of credentials so that the subjective
656  * security is overridden when an alternative set of credentials is used.  The
657  * security ID is specified in string form as a security context to be
658  * interpreted by the LSM.
659  */
660 int set_security_override_from_ctx(struct cred *new, const char *secctx)
661 {
662         u32 secid;
663         int ret;
664
665         ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
666         if (ret < 0)
667                 return ret;
668
669         return set_security_override(new, secid);
670 }
671 EXPORT_SYMBOL(set_security_override_from_ctx);
672
673 /**
674  * set_create_files_as - Set the LSM file create context in a set of credentials
675  * @new: The credentials to alter
676  * @inode: The inode to take the context from
677  *
678  * Change the LSM file creation context in a set of credentials to be the same
679  * as the object context of the specified inode, so that the new inodes have
680  * the same MAC context as that inode.
681  */
682 int set_create_files_as(struct cred *new, struct inode *inode)
683 {
684         new->fsuid = inode->i_uid;
685         new->fsgid = inode->i_gid;
686         return security_kernel_create_files_as(new, inode);
687 }
688 EXPORT_SYMBOL(set_create_files_as);
689
690 #ifdef CONFIG_DEBUG_CREDENTIALS
691
692 bool creds_are_invalid(const struct cred *cred)
693 {
694         if (cred->magic != CRED_MAGIC)
695                 return true;
696 #ifdef CONFIG_SECURITY_SELINUX
697         /*
698          * cred->security == NULL if security_cred_alloc_blank() or
699          * security_prepare_creds() returned an error.
700          */
701         if (selinux_is_enabled() && cred->security) {
702                 if ((unsigned long) cred->security < PAGE_SIZE)
703                         return true;
704                 if ((*(u32 *)cred->security & 0xffffff00) ==
705                     (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8))
706                         return true;
707         }
708 #endif
709         return false;
710 }
711 EXPORT_SYMBOL(creds_are_invalid);
712
713 /*
714  * dump invalid credentials
715  */
716 static void dump_invalid_creds(const struct cred *cred, const char *label,
717                                const struct task_struct *tsk)
718 {
719         printk(KERN_ERR "CRED: %s credentials: %p %s%s%s\n",
720                label, cred,
721                cred == &init_cred ? "[init]" : "",
722                cred == tsk->real_cred ? "[real]" : "",
723                cred == tsk->cred ? "[eff]" : "");
724         printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p\n",
725                cred->magic, cred->put_addr);
726         printk(KERN_ERR "CRED: ->usage=%d, subscr=%d\n",
727                atomic_read(&cred->usage),
728                read_cred_subscribers(cred));
729         printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d }\n",
730                 from_kuid_munged(&init_user_ns, cred->uid),
731                 from_kuid_munged(&init_user_ns, cred->euid),
732                 from_kuid_munged(&init_user_ns, cred->suid),
733                 from_kuid_munged(&init_user_ns, cred->fsuid));
734         printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d }\n",
735                 from_kgid_munged(&init_user_ns, cred->gid),
736                 from_kgid_munged(&init_user_ns, cred->egid),
737                 from_kgid_munged(&init_user_ns, cred->sgid),
738                 from_kgid_munged(&init_user_ns, cred->fsgid));
739 #ifdef CONFIG_SECURITY
740         printk(KERN_ERR "CRED: ->security is %p\n", cred->security);
741         if ((unsigned long) cred->security >= PAGE_SIZE &&
742             (((unsigned long) cred->security & 0xffffff00) !=
743              (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8)))
744                 printk(KERN_ERR "CRED: ->security {%x, %x}\n",
745                        ((u32*)cred->security)[0],
746                        ((u32*)cred->security)[1]);
747 #endif
748 }
749
750 /*
751  * report use of invalid credentials
752  */
753 void __invalid_creds(const struct cred *cred, const char *file, unsigned line)
754 {
755         printk(KERN_ERR "CRED: Invalid credentials\n");
756         printk(KERN_ERR "CRED: At %s:%u\n", file, line);
757         dump_invalid_creds(cred, "Specified", current);
758         BUG();
759 }
760 EXPORT_SYMBOL(__invalid_creds);
761
762 /*
763  * check the credentials on a process
764  */
765 void __validate_process_creds(struct task_struct *tsk,
766                               const char *file, unsigned line)
767 {
768         if (tsk->cred == tsk->real_cred) {
769                 if (unlikely(read_cred_subscribers(tsk->cred) < 2 ||
770                              creds_are_invalid(tsk->cred)))
771                         goto invalid_creds;
772         } else {
773                 if (unlikely(read_cred_subscribers(tsk->real_cred) < 1 ||
774                              read_cred_subscribers(tsk->cred) < 1 ||
775                              creds_are_invalid(tsk->real_cred) ||
776                              creds_are_invalid(tsk->cred)))
777                         goto invalid_creds;
778         }
779         return;
780
781 invalid_creds:
782         printk(KERN_ERR "CRED: Invalid process credentials\n");
783         printk(KERN_ERR "CRED: At %s:%u\n", file, line);
784
785         dump_invalid_creds(tsk->real_cred, "Real", tsk);
786         if (tsk->cred != tsk->real_cred)
787                 dump_invalid_creds(tsk->cred, "Effective", tsk);
788         else
789                 printk(KERN_ERR "CRED: Effective creds == Real creds\n");
790         BUG();
791 }
792 EXPORT_SYMBOL(__validate_process_creds);
793
794 /*
795  * check creds for do_exit()
796  */
797 void validate_creds_for_do_exit(struct task_struct *tsk)
798 {
799         kdebug("validate_creds_for_do_exit(%p,%p{%d,%d})",
800                tsk->real_cred, tsk->cred,
801                atomic_read(&tsk->cred->usage),
802                read_cred_subscribers(tsk->cred));
803
804         __validate_process_creds(tsk, __FILE__, __LINE__);
805 }
806
807 #endif /* CONFIG_DEBUG_CREDENTIALS */