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TOMOYO Linux Cross Reference
Linux/security/apparmor/policy.c

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  1 /*
  2  * AppArmor security module
  3  *
  4  * This file contains AppArmor policy manipulation functions
  5  *
  6  * Copyright (C) 1998-2008 Novell/SUSE
  7  * Copyright 2009-2010 Canonical Ltd.
  8  *
  9  * This program is free software; you can redistribute it and/or
 10  * modify it under the terms of the GNU General Public License as
 11  * published by the Free Software Foundation, version 2 of the
 12  * License.
 13  *
 14  *
 15  * AppArmor policy is based around profiles, which contain the rules a
 16  * task is confined by.  Every task in the system has a profile attached
 17  * to it determined either by matching "unconfined" tasks against the
 18  * visible set of profiles or by following a profiles attachment rules.
 19  *
 20  * Each profile exists in a profile namespace which is a container of
 21  * visible profiles.  Each namespace contains a special "unconfined" profile,
 22  * which doesn't enforce any confinement on a task beyond DAC.
 23  *
 24  * Namespace and profile names can be written together in either
 25  * of two syntaxes.
 26  *      :namespace:profile - used by kernel interfaces for easy detection
 27  *      namespace://profile - used by policy
 28  *
 29  * Profile names can not start with : or @ or ^ and may not contain \0
 30  *
 31  * Reserved profile names
 32  *      unconfined - special automatically generated unconfined profile
 33  *      inherit - special name to indicate profile inheritance
 34  *      null-XXXX-YYYY - special automatically generated learning profiles
 35  *
 36  * Namespace names may not start with / or @ and may not contain \0 or :
 37  * Reserved namespace names
 38  *      user-XXXX - user defined profiles
 39  *
 40  * a // in a profile or namespace name indicates a hierarchical name with the
 41  * name before the // being the parent and the name after the child.
 42  *
 43  * Profile and namespace hierarchies serve two different but similar purposes.
 44  * The namespace contains the set of visible profiles that are considered
 45  * for attachment.  The hierarchy of namespaces allows for virtualizing
 46  * the namespace so that for example a chroot can have its own set of profiles
 47  * which may define some local user namespaces.
 48  * The profile hierarchy severs two distinct purposes,
 49  * -  it allows for sub profiles or hats, which allows an application to run
 50  *    subprograms under its own profile with different restriction than it
 51  *    self, and not have it use the system profile.
 52  *    eg. if a mail program starts an editor, the policy might make the
 53  *        restrictions tighter on the editor tighter than the mail program,
 54  *        and definitely different than general editor restrictions
 55  * - it allows for binary hierarchy of profiles, so that execution history
 56  *   is preserved.  This feature isn't exploited by AppArmor reference policy
 57  *   but is allowed.  NOTE: this is currently suboptimal because profile
 58  *   aliasing is not currently implemented so that a profile for each
 59  *   level must be defined.
 60  *   eg. /bin/bash///bin/ls as a name would indicate /bin/ls was started
 61  *       from /bin/bash
 62  *
 63  *   A profile or namespace name that can contain one or more // separators
 64  *   is referred to as an hname (hierarchical).
 65  *   eg.  /bin/bash//bin/ls
 66  *
 67  *   An fqname is a name that may contain both namespace and profile hnames.
 68  *   eg. :ns:/bin/bash//bin/ls
 69  *
 70  * NOTES:
 71  *   - locking of profile lists is currently fairly coarse.  All profile
 72  *     lists within a namespace use the namespace lock.
 73  * FIXME: move profile lists to using rcu_lists
 74  */
 75 
 76 #include <linux/slab.h>
 77 #include <linux/spinlock.h>
 78 #include <linux/string.h>
 79 
 80 #include "include/apparmor.h"
 81 #include "include/capability.h"
 82 #include "include/context.h"
 83 #include "include/file.h"
 84 #include "include/ipc.h"
 85 #include "include/match.h"
 86 #include "include/path.h"
 87 #include "include/policy.h"
 88 #include "include/policy_unpack.h"
 89 #include "include/resource.h"
 90 #include "include/sid.h"
 91 
 92 
 93 /* root profile namespace */
 94 struct aa_namespace *root_ns;
 95 
 96 const char *const profile_mode_names[] = {
 97         "enforce",
 98         "complain",
 99         "kill",
100 };
101 
102 /**
103  * hname_tail - find the last component of an hname
104  * @name: hname to find the base profile name component of  (NOT NULL)
105  *
106  * Returns: the tail (base profile name) name component of an hname
107  */
108 static const char *hname_tail(const char *hname)
109 {
110         char *split;
111         hname = strim((char *)hname);
112         for (split = strstr(hname, "//"); split; split = strstr(hname, "//"))
113                 hname = split + 2;
114 
115         return hname;
116 }
117 
118 /**
119  * policy_init - initialize a policy structure
120  * @policy: policy to initialize  (NOT NULL)
121  * @prefix: prefix name if any is required.  (MAYBE NULL)
122  * @name: name of the policy, init will make a copy of it  (NOT NULL)
123  *
124  * Note: this fn creates a copy of strings passed in
125  *
126  * Returns: true if policy init successful
127  */
128 static bool policy_init(struct aa_policy *policy, const char *prefix,
129                         const char *name)
130 {
131         /* freed by policy_free */
132         if (prefix) {
133                 policy->hname = kmalloc(strlen(prefix) + strlen(name) + 3,
134                                         GFP_KERNEL);
135                 if (policy->hname)
136                         sprintf(policy->hname, "%s//%s", prefix, name);
137         } else
138                 policy->hname = kstrdup(name, GFP_KERNEL);
139         if (!policy->hname)
140                 return 0;
141         /* base.name is a substring of fqname */
142         policy->name = (char *)hname_tail(policy->hname);
143         INIT_LIST_HEAD(&policy->list);
144         INIT_LIST_HEAD(&policy->profiles);
145         kref_init(&policy->count);
146 
147         return 1;
148 }
149 
150 /**
151  * policy_destroy - free the elements referenced by @policy
152  * @policy: policy that is to have its elements freed  (NOT NULL)
153  */
154 static void policy_destroy(struct aa_policy *policy)
155 {
156         /* still contains profiles -- invalid */
157         if (!list_empty(&policy->profiles)) {
158                 AA_ERROR("%s: internal error, "
159                          "policy '%s' still contains profiles\n",
160                          __func__, policy->name);
161                 BUG();
162         }
163         if (!list_empty(&policy->list)) {
164                 AA_ERROR("%s: internal error, policy '%s' still on list\n",
165                          __func__, policy->name);
166                 BUG();
167         }
168 
169         /* don't free name as its a subset of hname */
170         kzfree(policy->hname);
171 }
172 
173 /**
174  * __policy_find - find a policy by @name on a policy list
175  * @head: list to search  (NOT NULL)
176  * @name: name to search for  (NOT NULL)
177  *
178  * Requires: correct locks for the @head list be held
179  *
180  * Returns: unrefcounted policy that match @name or NULL if not found
181  */
182 static struct aa_policy *__policy_find(struct list_head *head, const char *name)
183 {
184         struct aa_policy *policy;
185 
186         list_for_each_entry(policy, head, list) {
187                 if (!strcmp(policy->name, name))
188                         return policy;
189         }
190         return NULL;
191 }
192 
193 /**
194  * __policy_strn_find - find a policy that's name matches @len chars of @str
195  * @head: list to search  (NOT NULL)
196  * @str: string to search for  (NOT NULL)
197  * @len: length of match required
198  *
199  * Requires: correct locks for the @head list be held
200  *
201  * Returns: unrefcounted policy that match @str or NULL if not found
202  *
203  * if @len == strlen(@strlen) then this is equiv to __policy_find
204  * other wise it allows searching for policy by a partial match of name
205  */
206 static struct aa_policy *__policy_strn_find(struct list_head *head,
207                                             const char *str, int len)
208 {
209         struct aa_policy *policy;
210 
211         list_for_each_entry(policy, head, list) {
212                 if (aa_strneq(policy->name, str, len))
213                         return policy;
214         }
215 
216         return NULL;
217 }
218 
219 /*
220  * Routines for AppArmor namespaces
221  */
222 
223 static const char *hidden_ns_name = "---";
224 /**
225  * aa_ns_visible - test if @view is visible from @curr
226  * @curr: namespace to treat as the parent (NOT NULL)
227  * @view:  namespace to test if visible from @curr (NOT NULL)
228  *
229  * Returns: true if @view is visible from @curr else false
230  */
231 bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view)
232 {
233         if (curr == view)
234                 return true;
235 
236         for ( ; view; view = view->parent) {
237                 if (view->parent == curr)
238                         return true;
239         }
240         return false;
241 }
242 
243 /**
244  * aa_na_name - Find the ns name to display for @view from @curr
245  * @curr - current namespace (NOT NULL)
246  * @view - namespace attempting to view (NOT NULL)
247  *
248  * Returns: name of @view visible from @curr
249  */
250 const char *aa_ns_name(struct aa_namespace *curr, struct aa_namespace *view)
251 {
252         /* if view == curr then the namespace name isn't displayed */
253         if (curr == view)
254                 return "";
255 
256         if (aa_ns_visible(curr, view)) {
257                 /* at this point if a ns is visible it is in a view ns
258                  * thus the curr ns.hname is a prefix of its name.
259                  * Only output the virtualized portion of the name
260                  * Add + 2 to skip over // separating curr hname prefix
261                  * from the visible tail of the views hname
262                  */
263                 return view->base.hname + strlen(curr->base.hname) + 2;
264         } else
265                 return hidden_ns_name;
266 }
267 
268 /**
269  * alloc_namespace - allocate, initialize and return a new namespace
270  * @prefix: parent namespace name (MAYBE NULL)
271  * @name: a preallocated name  (NOT NULL)
272  *
273  * Returns: refcounted namespace or NULL on failure.
274  */
275 static struct aa_namespace *alloc_namespace(const char *prefix,
276                                             const char *name)
277 {
278         struct aa_namespace *ns;
279 
280         ns = kzalloc(sizeof(*ns), GFP_KERNEL);
281         AA_DEBUG("%s(%p)\n", __func__, ns);
282         if (!ns)
283                 return NULL;
284         if (!policy_init(&ns->base, prefix, name))
285                 goto fail_ns;
286 
287         INIT_LIST_HEAD(&ns->sub_ns);
288         rwlock_init(&ns->lock);
289 
290         /* released by free_namespace */
291         ns->unconfined = aa_alloc_profile("unconfined");
292         if (!ns->unconfined)
293                 goto fail_unconfined;
294 
295         ns->unconfined->sid = aa_alloc_sid();
296         ns->unconfined->flags = PFLAG_UNCONFINED | PFLAG_IX_ON_NAME_ERROR |
297             PFLAG_IMMUTABLE;
298 
299         /*
300          * released by free_namespace, however __remove_namespace breaks
301          * the cyclic references (ns->unconfined, and unconfined->ns) and
302          * replaces with refs to parent namespace unconfined
303          */
304         ns->unconfined->ns = aa_get_namespace(ns);
305 
306         return ns;
307 
308 fail_unconfined:
309         kzfree(ns->base.hname);
310 fail_ns:
311         kzfree(ns);
312         return NULL;
313 }
314 
315 /**
316  * free_namespace - free a profile namespace
317  * @ns: the namespace to free  (MAYBE NULL)
318  *
319  * Requires: All references to the namespace must have been put, if the
320  *           namespace was referenced by a profile confining a task,
321  */
322 static void free_namespace(struct aa_namespace *ns)
323 {
324         if (!ns)
325                 return;
326 
327         policy_destroy(&ns->base);
328         aa_put_namespace(ns->parent);
329 
330         if (ns->unconfined && ns->unconfined->ns == ns)
331                 ns->unconfined->ns = NULL;
332 
333         aa_put_profile(ns->unconfined);
334         kzfree(ns);
335 }
336 
337 /**
338  * aa_free_namespace_kref - free aa_namespace by kref (see aa_put_namespace)
339  * @kr: kref callback for freeing of a namespace  (NOT NULL)
340  */
341 void aa_free_namespace_kref(struct kref *kref)
342 {
343         free_namespace(container_of(kref, struct aa_namespace, base.count));
344 }
345 
346 /**
347  * __aa_find_namespace - find a namespace on a list by @name
348  * @head: list to search for namespace on  (NOT NULL)
349  * @name: name of namespace to look for  (NOT NULL)
350  *
351  * Returns: unrefcounted namespace
352  *
353  * Requires: ns lock be held
354  */
355 static struct aa_namespace *__aa_find_namespace(struct list_head *head,
356                                                 const char *name)
357 {
358         return (struct aa_namespace *)__policy_find(head, name);
359 }
360 
361 /**
362  * aa_find_namespace  -  look up a profile namespace on the namespace list
363  * @root: namespace to search in  (NOT NULL)
364  * @name: name of namespace to find  (NOT NULL)
365  *
366  * Returns: a refcounted namespace on the list, or NULL if no namespace
367  *          called @name exists.
368  *
369  * refcount released by caller
370  */
371 struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
372                                        const char *name)
373 {
374         struct aa_namespace *ns = NULL;
375 
376         read_lock(&root->lock);
377         ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name));
378         read_unlock(&root->lock);
379 
380         return ns;
381 }
382 
383 /**
384  * aa_prepare_namespace - find an existing or create a new namespace of @name
385  * @name: the namespace to find or add  (MAYBE NULL)
386  *
387  * Returns: refcounted namespace or NULL if failed to create one
388  */
389 static struct aa_namespace *aa_prepare_namespace(const char *name)
390 {
391         struct aa_namespace *ns, *root;
392 
393         root = aa_current_profile()->ns;
394 
395         write_lock(&root->lock);
396 
397         /* if name isn't specified the profile is loaded to the current ns */
398         if (!name) {
399                 /* released by caller */
400                 ns = aa_get_namespace(root);
401                 goto out;
402         }
403 
404         /* try and find the specified ns and if it doesn't exist create it */
405         /* released by caller */
406         ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name));
407         if (!ns) {
408                 /* namespace not found */
409                 struct aa_namespace *new_ns;
410                 write_unlock(&root->lock);
411                 new_ns = alloc_namespace(root->base.hname, name);
412                 if (!new_ns)
413                         return NULL;
414                 write_lock(&root->lock);
415                 /* test for race when new_ns was allocated */
416                 ns = __aa_find_namespace(&root->sub_ns, name);
417                 if (!ns) {
418                         /* add parent ref */
419                         new_ns->parent = aa_get_namespace(root);
420 
421                         list_add(&new_ns->base.list, &root->sub_ns);
422                         /* add list ref */
423                         ns = aa_get_namespace(new_ns);
424                 } else {
425                         /* raced so free the new one */
426                         free_namespace(new_ns);
427                         /* get reference on namespace */
428                         aa_get_namespace(ns);
429                 }
430         }
431 out:
432         write_unlock(&root->lock);
433 
434         /* return ref */
435         return ns;
436 }
437 
438 /**
439  * __list_add_profile - add a profile to a list
440  * @list: list to add it to  (NOT NULL)
441  * @profile: the profile to add  (NOT NULL)
442  *
443  * refcount @profile, should be put by __list_remove_profile
444  *
445  * Requires: namespace lock be held, or list not be shared
446  */
447 static void __list_add_profile(struct list_head *list,
448                                struct aa_profile *profile)
449 {
450         list_add(&profile->base.list, list);
451         /* get list reference */
452         aa_get_profile(profile);
453 }
454 
455 /**
456  * __list_remove_profile - remove a profile from the list it is on
457  * @profile: the profile to remove  (NOT NULL)
458  *
459  * remove a profile from the list, warning generally removal should
460  * be done with __replace_profile as most profile removals are
461  * replacements to the unconfined profile.
462  *
463  * put @profile list refcount
464  *
465  * Requires: namespace lock be held, or list not have been live
466  */
467 static void __list_remove_profile(struct aa_profile *profile)
468 {
469         list_del_init(&profile->base.list);
470         if (!(profile->flags & PFLAG_NO_LIST_REF))
471                 /* release list reference */
472                 aa_put_profile(profile);
473 }
474 
475 /**
476  * __replace_profile - replace @old with @new on a list
477  * @old: profile to be replaced  (NOT NULL)
478  * @new: profile to replace @old with  (NOT NULL)
479  *
480  * Will duplicate and refcount elements that @new inherits from @old
481  * and will inherit @old children.
482  *
483  * refcount @new for list, put @old list refcount
484  *
485  * Requires: namespace list lock be held, or list not be shared
486  */
487 static void __replace_profile(struct aa_profile *old, struct aa_profile *new)
488 {
489         struct aa_policy *policy;
490         struct aa_profile *child, *tmp;
491 
492         if (old->parent)
493                 policy = &old->parent->base;
494         else
495                 policy = &old->ns->base;
496 
497         /* released when @new is freed */
498         new->parent = aa_get_profile(old->parent);
499         new->ns = aa_get_namespace(old->ns);
500         new->sid = old->sid;
501         __list_add_profile(&policy->profiles, new);
502         /* inherit children */
503         list_for_each_entry_safe(child, tmp, &old->base.profiles, base.list) {
504                 aa_put_profile(child->parent);
505                 child->parent = aa_get_profile(new);
506                 /* list refcount transferred to @new*/
507                 list_move(&child->base.list, &new->base.profiles);
508         }
509 
510         /* released by free_profile */
511         old->replacedby = aa_get_profile(new);
512         __list_remove_profile(old);
513 }
514 
515 static void __profile_list_release(struct list_head *head);
516 
517 /**
518  * __remove_profile - remove old profile, and children
519  * @profile: profile to be replaced  (NOT NULL)
520  *
521  * Requires: namespace list lock be held, or list not be shared
522  */
523 static void __remove_profile(struct aa_profile *profile)
524 {
525         /* release any children lists first */
526         __profile_list_release(&profile->base.profiles);
527         /* released by free_profile */
528         profile->replacedby = aa_get_profile(profile->ns->unconfined);
529         __list_remove_profile(profile);
530 }
531 
532 /**
533  * __profile_list_release - remove all profiles on the list and put refs
534  * @head: list of profiles  (NOT NULL)
535  *
536  * Requires: namespace lock be held
537  */
538 static void __profile_list_release(struct list_head *head)
539 {
540         struct aa_profile *profile, *tmp;
541         list_for_each_entry_safe(profile, tmp, head, base.list)
542                 __remove_profile(profile);
543 }
544 
545 static void __ns_list_release(struct list_head *head);
546 
547 /**
548  * destroy_namespace - remove everything contained by @ns
549  * @ns: namespace to have it contents removed  (NOT NULL)
550  */
551 static void destroy_namespace(struct aa_namespace *ns)
552 {
553         if (!ns)
554                 return;
555 
556         write_lock(&ns->lock);
557         /* release all profiles in this namespace */
558         __profile_list_release(&ns->base.profiles);
559 
560         /* release all sub namespaces */
561         __ns_list_release(&ns->sub_ns);
562 
563         write_unlock(&ns->lock);
564 }
565 
566 /**
567  * __remove_namespace - remove a namespace and all its children
568  * @ns: namespace to be removed  (NOT NULL)
569  *
570  * Requires: ns->parent->lock be held and ns removed from parent.
571  */
572 static void __remove_namespace(struct aa_namespace *ns)
573 {
574         struct aa_profile *unconfined = ns->unconfined;
575 
576         /* remove ns from namespace list */
577         list_del_init(&ns->base.list);
578 
579         /*
580          * break the ns, unconfined profile cyclic reference and forward
581          * all new unconfined profiles requests to the parent namespace
582          * This will result in all confined tasks that have a profile
583          * being removed, inheriting the parent->unconfined profile.
584          */
585         if (ns->parent)
586                 ns->unconfined = aa_get_profile(ns->parent->unconfined);
587 
588         destroy_namespace(ns);
589 
590         /* release original ns->unconfined ref */
591         aa_put_profile(unconfined);
592         /* release ns->base.list ref, from removal above */
593         aa_put_namespace(ns);
594 }
595 
596 /**
597  * __ns_list_release - remove all profile namespaces on the list put refs
598  * @head: list of profile namespaces  (NOT NULL)
599  *
600  * Requires: namespace lock be held
601  */
602 static void __ns_list_release(struct list_head *head)
603 {
604         struct aa_namespace *ns, *tmp;
605         list_for_each_entry_safe(ns, tmp, head, base.list)
606                 __remove_namespace(ns);
607 
608 }
609 
610 /**
611  * aa_alloc_root_ns - allocate the root profile namespace
612  *
613  * Returns: %0 on success else error
614  *
615  */
616 int __init aa_alloc_root_ns(void)
617 {
618         /* released by aa_free_root_ns - used as list ref*/
619         root_ns = alloc_namespace(NULL, "root");
620         if (!root_ns)
621                 return -ENOMEM;
622 
623         return 0;
624 }
625 
626  /**
627   * aa_free_root_ns - free the root profile namespace
628   */
629 void __init aa_free_root_ns(void)
630  {
631          struct aa_namespace *ns = root_ns;
632          root_ns = NULL;
633 
634          destroy_namespace(ns);
635          aa_put_namespace(ns);
636 }
637 
638 /**
639  * aa_alloc_profile - allocate, initialize and return a new profile
640  * @hname: name of the profile  (NOT NULL)
641  *
642  * Returns: refcount profile or NULL on failure
643  */
644 struct aa_profile *aa_alloc_profile(const char *hname)
645 {
646         struct aa_profile *profile;
647 
648         /* freed by free_profile - usually through aa_put_profile */
649         profile = kzalloc(sizeof(*profile), GFP_KERNEL);
650         if (!profile)
651                 return NULL;
652 
653         if (!policy_init(&profile->base, NULL, hname)) {
654                 kzfree(profile);
655                 return NULL;
656         }
657 
658         /* refcount released by caller */
659         return profile;
660 }
661 
662 /**
663  * aa_new_null_profile - create a new null-X learning profile
664  * @parent: profile that caused this profile to be created (NOT NULL)
665  * @hat: true if the null- learning profile is a hat
666  *
667  * Create a null- complain mode profile used in learning mode.  The name of
668  * the profile is unique and follows the format of parent//null-sid.
669  *
670  * null profiles are added to the profile list but the list does not
671  * hold a count on them so that they are automatically released when
672  * not in use.
673  *
674  * Returns: new refcounted profile else NULL on failure
675  */
676 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat)
677 {
678         struct aa_profile *profile = NULL;
679         char *name;
680         u32 sid = aa_alloc_sid();
681 
682         /* freed below */
683         name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, GFP_KERNEL);
684         if (!name)
685                 goto fail;
686         sprintf(name, "%s//null-%x", parent->base.hname, sid);
687 
688         profile = aa_alloc_profile(name);
689         kfree(name);
690         if (!profile)
691                 goto fail;
692 
693         profile->sid = sid;
694         profile->mode = APPARMOR_COMPLAIN;
695         profile->flags = PFLAG_NULL;
696         if (hat)
697                 profile->flags |= PFLAG_HAT;
698 
699         /* released on free_profile */
700         profile->parent = aa_get_profile(parent);
701         profile->ns = aa_get_namespace(parent->ns);
702 
703         write_lock(&profile->ns->lock);
704         __list_add_profile(&parent->base.profiles, profile);
705         write_unlock(&profile->ns->lock);
706 
707         /* refcount released by caller */
708         return profile;
709 
710 fail:
711         aa_free_sid(sid);
712         return NULL;
713 }
714 
715 /**
716  * free_profile - free a profile
717  * @profile: the profile to free  (MAYBE NULL)
718  *
719  * Free a profile, its hats and null_profile. All references to the profile,
720  * its hats and null_profile must have been put.
721  *
722  * If the profile was referenced from a task context, free_profile() will
723  * be called from an rcu callback routine, so we must not sleep here.
724  */
725 static void free_profile(struct aa_profile *profile)
726 {
727         struct aa_profile *p;
728 
729         AA_DEBUG("%s(%p)\n", __func__, profile);
730 
731         if (!profile)
732                 return;
733 
734         if (!list_empty(&profile->base.list)) {
735                 AA_ERROR("%s: internal error, "
736                          "profile '%s' still on ns list\n",
737                          __func__, profile->base.name);
738                 BUG();
739         }
740 
741         /* free children profiles */
742         policy_destroy(&profile->base);
743         aa_put_profile(profile->parent);
744 
745         aa_put_namespace(profile->ns);
746         kzfree(profile->rename);
747 
748         aa_free_file_rules(&profile->file);
749         aa_free_cap_rules(&profile->caps);
750         aa_free_rlimit_rules(&profile->rlimits);
751 
752         aa_free_sid(profile->sid);
753         aa_put_dfa(profile->xmatch);
754         aa_put_dfa(profile->policy.dfa);
755 
756         /* put the profile reference for replacedby, but not via
757          * put_profile(kref_put).
758          * replacedby can form a long chain that can result in cascading
759          * frees that blows the stack because kref_put makes a nested fn
760          * call (it looks like recursion, with free_profile calling
761          * free_profile) for each profile in the chain lp#1056078.
762          */
763         for (p = profile->replacedby; p; ) {
764                 if (atomic_dec_and_test(&p->base.count.refcount)) {
765                         /* no more refs on p, grab its replacedby */
766                         struct aa_profile *next = p->replacedby;
767                         /* break the chain */
768                         p->replacedby = NULL;
769                         /* now free p, chain is broken */
770                         free_profile(p);
771 
772                         /* follow up with next profile in the chain */
773                         p = next;
774                 } else
775                         break;
776         }
777 
778         kzfree(profile);
779 }
780 
781 /**
782  * aa_free_profile_kref - free aa_profile by kref (called by aa_put_profile)
783  * @kr: kref callback for freeing of a profile  (NOT NULL)
784  */
785 void aa_free_profile_kref(struct kref *kref)
786 {
787         struct aa_profile *p = container_of(kref, struct aa_profile,
788                                             base.count);
789 
790         free_profile(p);
791 }
792 
793 /* TODO: profile accounting - setup in remove */
794 
795 /**
796  * __find_child - find a profile on @head list with a name matching @name
797  * @head: list to search  (NOT NULL)
798  * @name: name of profile (NOT NULL)
799  *
800  * Requires: ns lock protecting list be held
801  *
802  * Returns: unrefcounted profile ptr, or NULL if not found
803  */
804 static struct aa_profile *__find_child(struct list_head *head, const char *name)
805 {
806         return (struct aa_profile *)__policy_find(head, name);
807 }
808 
809 /**
810  * __strn_find_child - find a profile on @head list using substring of @name
811  * @head: list to search  (NOT NULL)
812  * @name: name of profile (NOT NULL)
813  * @len: length of @name substring to match
814  *
815  * Requires: ns lock protecting list be held
816  *
817  * Returns: unrefcounted profile ptr, or NULL if not found
818  */
819 static struct aa_profile *__strn_find_child(struct list_head *head,
820                                             const char *name, int len)
821 {
822         return (struct aa_profile *)__policy_strn_find(head, name, len);
823 }
824 
825 /**
826  * aa_find_child - find a profile by @name in @parent
827  * @parent: profile to search  (NOT NULL)
828  * @name: profile name to search for  (NOT NULL)
829  *
830  * Returns: a refcounted profile or NULL if not found
831  */
832 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name)
833 {
834         struct aa_profile *profile;
835 
836         read_lock(&parent->ns->lock);
837         profile = aa_get_profile(__find_child(&parent->base.profiles, name));
838         read_unlock(&parent->ns->lock);
839 
840         /* refcount released by caller */
841         return profile;
842 }
843 
844 /**
845  * __lookup_parent - lookup the parent of a profile of name @hname
846  * @ns: namespace to lookup profile in  (NOT NULL)
847  * @hname: hierarchical profile name to find parent of  (NOT NULL)
848  *
849  * Lookups up the parent of a fully qualified profile name, the profile
850  * that matches hname does not need to exist, in general this
851  * is used to load a new profile.
852  *
853  * Requires: ns->lock be held
854  *
855  * Returns: unrefcounted policy or NULL if not found
856  */
857 static struct aa_policy *__lookup_parent(struct aa_namespace *ns,
858                                          const char *hname)
859 {
860         struct aa_policy *policy;
861         struct aa_profile *profile = NULL;
862         char *split;
863 
864         policy = &ns->base;
865 
866         for (split = strstr(hname, "//"); split;) {
867                 profile = __strn_find_child(&policy->profiles, hname,
868                                             split - hname);
869                 if (!profile)
870                         return NULL;
871                 policy = &profile->base;
872                 hname = split + 2;
873                 split = strstr(hname, "//");
874         }
875         if (!profile)
876                 return &ns->base;
877         return &profile->base;
878 }
879 
880 /**
881  * __lookup_profile - lookup the profile matching @hname
882  * @base: base list to start looking up profile name from  (NOT NULL)
883  * @hname: hierarchical profile name  (NOT NULL)
884  *
885  * Requires: ns->lock be held
886  *
887  * Returns: unrefcounted profile pointer or NULL if not found
888  *
889  * Do a relative name lookup, recursing through profile tree.
890  */
891 static struct aa_profile *__lookup_profile(struct aa_policy *base,
892                                            const char *hname)
893 {
894         struct aa_profile *profile = NULL;
895         char *split;
896 
897         for (split = strstr(hname, "//"); split;) {
898                 profile = __strn_find_child(&base->profiles, hname,
899                                             split - hname);
900                 if (!profile)
901                         return NULL;
902 
903                 base = &profile->base;
904                 hname = split + 2;
905                 split = strstr(hname, "//");
906         }
907 
908         profile = __find_child(&base->profiles, hname);
909 
910         return profile;
911 }
912 
913 /**
914  * aa_lookup_profile - find a profile by its full or partial name
915  * @ns: the namespace to start from (NOT NULL)
916  * @hname: name to do lookup on.  Does not contain namespace prefix (NOT NULL)
917  *
918  * Returns: refcounted profile or NULL if not found
919  */
920 struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *hname)
921 {
922         struct aa_profile *profile;
923 
924         read_lock(&ns->lock);
925         profile = aa_get_profile(__lookup_profile(&ns->base, hname));
926         read_unlock(&ns->lock);
927 
928         /* the unconfined profile is not in the regular profile list */
929         if (!profile && strcmp(hname, "unconfined") == 0)
930                 profile = aa_get_profile(ns->unconfined);
931 
932         /* refcount released by caller */
933         return profile;
934 }
935 
936 /**
937  * replacement_allowed - test to see if replacement is allowed
938  * @profile: profile to test if it can be replaced  (MAYBE NULL)
939  * @noreplace: true if replacement shouldn't be allowed but addition is okay
940  * @info: Returns - info about why replacement failed (NOT NULL)
941  *
942  * Returns: %0 if replacement allowed else error code
943  */
944 static int replacement_allowed(struct aa_profile *profile, int noreplace,
945                                const char **info)
946 {
947         if (profile) {
948                 if (profile->flags & PFLAG_IMMUTABLE) {
949                         *info = "cannot replace immutible profile";
950                         return -EPERM;
951                 } else if (noreplace) {
952                         *info = "profile already exists";
953                         return -EEXIST;
954                 }
955         }
956         return 0;
957 }
958 
959 /**
960  * __add_new_profile - simple wrapper around __list_add_profile
961  * @ns: namespace that profile is being added to  (NOT NULL)
962  * @policy: the policy container to add the profile to  (NOT NULL)
963  * @profile: profile to add  (NOT NULL)
964  *
965  * add a profile to a list and do other required basic allocations
966  */
967 static void __add_new_profile(struct aa_namespace *ns, struct aa_policy *policy,
968                               struct aa_profile *profile)
969 {
970         if (policy != &ns->base)
971                 /* released on profile replacement or free_profile */
972                 profile->parent = aa_get_profile((struct aa_profile *) policy);
973         __list_add_profile(&policy->profiles, profile);
974         /* released on free_profile */
975         profile->sid = aa_alloc_sid();
976         profile->ns = aa_get_namespace(ns);
977 }
978 
979 /**
980  * aa_audit_policy - Do auditing of policy changes
981  * @op: policy operation being performed
982  * @gfp: memory allocation flags
983  * @name: name of profile being manipulated (NOT NULL)
984  * @info: any extra information to be audited (MAYBE NULL)
985  * @error: error code
986  *
987  * Returns: the error to be returned after audit is done
988  */
989 static int audit_policy(int op, gfp_t gfp, const char *name, const char *info,
990                         int error)
991 {
992         struct common_audit_data sa;
993         struct apparmor_audit_data aad = {0,};
994         sa.type = LSM_AUDIT_DATA_NONE;
995         sa.aad = &aad;
996         aad.op = op;
997         aad.name = name;
998         aad.info = info;
999         aad.error = error;
1000 
1001         return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp,
1002                         &sa, NULL);
1003 }
1004 
1005 /**
1006  * aa_may_manage_policy - can the current task manage policy
1007  * @op: the policy manipulation operation being done
1008  *
1009  * Returns: true if the task is allowed to manipulate policy
1010  */
1011 bool aa_may_manage_policy(int op)
1012 {
1013         /* check if loading policy is locked out */
1014         if (aa_g_lock_policy) {
1015                 audit_policy(op, GFP_KERNEL, NULL, "policy_locked", -EACCES);
1016                 return 0;
1017         }
1018 
1019         if (!capable(CAP_MAC_ADMIN)) {
1020                 audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES);
1021                 return 0;
1022         }
1023 
1024         return 1;
1025 }
1026 
1027 /**
1028  * aa_replace_profiles - replace profile(s) on the profile list
1029  * @udata: serialized data stream  (NOT NULL)
1030  * @size: size of the serialized data stream
1031  * @noreplace: true if only doing addition, no replacement allowed
1032  *
1033  * unpack and replace a profile on the profile list and uses of that profile
1034  * by any aa_task_cxt.  If the profile does not exist on the profile list
1035  * it is added.
1036  *
1037  * Returns: size of data consumed else error code on failure.
1038  */
1039 ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace)
1040 {
1041         struct aa_policy *policy;
1042         struct aa_profile *old_profile = NULL, *new_profile = NULL;
1043         struct aa_profile *rename_profile = NULL;
1044         struct aa_namespace *ns = NULL;
1045         const char *ns_name, *name = NULL, *info = NULL;
1046         int op = OP_PROF_REPL;
1047         ssize_t error;
1048 
1049         /* released below */
1050         new_profile = aa_unpack(udata, size, &ns_name);
1051         if (IS_ERR(new_profile)) {
1052                 error = PTR_ERR(new_profile);
1053                 new_profile = NULL;
1054                 goto fail;
1055         }
1056 
1057         /* released below */
1058         ns = aa_prepare_namespace(ns_name);
1059         if (!ns) {
1060                 info = "failed to prepare namespace";
1061                 error = -ENOMEM;
1062                 name = ns_name;
1063                 goto fail;
1064         }
1065 
1066         name = new_profile->base.hname;
1067 
1068         write_lock(&ns->lock);
1069         /* no ref on policy only use inside lock */
1070         policy = __lookup_parent(ns, new_profile->base.hname);
1071 
1072         if (!policy) {
1073                 info = "parent does not exist";
1074                 error = -ENOENT;
1075                 goto audit;
1076         }
1077 
1078         old_profile = __find_child(&policy->profiles, new_profile->base.name);
1079         /* released below */
1080         aa_get_profile(old_profile);
1081 
1082         if (new_profile->rename) {
1083                 rename_profile = __lookup_profile(&ns->base,
1084                                                   new_profile->rename);
1085                 /* released below */
1086                 aa_get_profile(rename_profile);
1087 
1088                 if (!rename_profile) {
1089                         info = "profile to rename does not exist";
1090                         name = new_profile->rename;
1091                         error = -ENOENT;
1092                         goto audit;
1093                 }
1094         }
1095 
1096         error = replacement_allowed(old_profile, noreplace, &info);
1097         if (error)
1098                 goto audit;
1099 
1100         error = replacement_allowed(rename_profile, noreplace, &info);
1101         if (error)
1102                 goto audit;
1103 
1104 audit:
1105         if (!old_profile && !rename_profile)
1106                 op = OP_PROF_LOAD;
1107 
1108         error = audit_policy(op, GFP_ATOMIC, name, info, error);
1109 
1110         if (!error) {
1111                 if (rename_profile)
1112                         __replace_profile(rename_profile, new_profile);
1113                 if (old_profile) {
1114                         /* when there are both rename and old profiles
1115                          * inherit old profiles sid
1116                          */
1117                         if (rename_profile)
1118                                 aa_free_sid(new_profile->sid);
1119                         __replace_profile(old_profile, new_profile);
1120                 }
1121                 if (!(old_profile || rename_profile))
1122                         __add_new_profile(ns, policy, new_profile);
1123         }
1124         write_unlock(&ns->lock);
1125 
1126 out:
1127         aa_put_namespace(ns);
1128         aa_put_profile(rename_profile);
1129         aa_put_profile(old_profile);
1130         aa_put_profile(new_profile);
1131         if (error)
1132                 return error;
1133         return size;
1134 
1135 fail:
1136         error = audit_policy(op, GFP_KERNEL, name, info, error);
1137         goto out;
1138 }
1139 
1140 /**
1141  * aa_remove_profiles - remove profile(s) from the system
1142  * @fqname: name of the profile or namespace to remove  (NOT NULL)
1143  * @size: size of the name
1144  *
1145  * Remove a profile or sub namespace from the current namespace, so that
1146  * they can not be found anymore and mark them as replaced by unconfined
1147  *
1148  * NOTE: removing confinement does not restore rlimits to preconfinemnet values
1149  *
1150  * Returns: size of data consume else error code if fails
1151  */
1152 ssize_t aa_remove_profiles(char *fqname, size_t size)
1153 {
1154         struct aa_namespace *root, *ns = NULL;
1155         struct aa_profile *profile = NULL;
1156         const char *name = fqname, *info = NULL;
1157         ssize_t error = 0;
1158 
1159         if (*fqname == 0) {
1160                 info = "no profile specified";
1161                 error = -ENOENT;
1162                 goto fail;
1163         }
1164 
1165         root = aa_current_profile()->ns;
1166 
1167         if (fqname[0] == ':') {
1168                 char *ns_name;
1169                 name = aa_split_fqname(fqname, &ns_name);
1170                 if (ns_name) {
1171                         /* released below */
1172                         ns = aa_find_namespace(root, ns_name);
1173                         if (!ns) {
1174                                 info = "namespace does not exist";
1175                                 error = -ENOENT;
1176                                 goto fail;
1177                         }
1178                 }
1179         } else
1180                 /* released below */
1181                 ns = aa_get_namespace(root);
1182 
1183         if (!name) {
1184                 /* remove namespace - can only happen if fqname[0] == ':' */
1185                 write_lock(&ns->parent->lock);
1186                 __remove_namespace(ns);
1187                 write_unlock(&ns->parent->lock);
1188         } else {
1189                 /* remove profile */
1190                 write_lock(&ns->lock);
1191                 profile = aa_get_profile(__lookup_profile(&ns->base, name));
1192                 if (!profile) {
1193                         error = -ENOENT;
1194                         info = "profile does not exist";
1195                         goto fail_ns_lock;
1196                 }
1197                 name = profile->base.hname;
1198                 __remove_profile(profile);
1199                 write_unlock(&ns->lock);
1200         }
1201 
1202         /* don't fail removal if audit fails */
1203         (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
1204         aa_put_namespace(ns);
1205         aa_put_profile(profile);
1206         return size;
1207 
1208 fail_ns_lock:
1209         write_unlock(&ns->lock);
1210         aa_put_namespace(ns);
1211 
1212 fail:
1213         (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
1214         return error;
1215 }
1216 

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