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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 
 91 
 92 /* root profile namespace */
 93 struct aa_namespace *root_ns;
 94 
 95 const char *const aa_profile_mode_names[] = {
 96         "enforce",
 97         "complain",
 98         "kill",
 99         "unconfined",
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 
146         return 1;
147 }
148 
149 /**
150  * policy_destroy - free the elements referenced by @policy
151  * @policy: policy that is to have its elements freed  (NOT NULL)
152  */
153 static void policy_destroy(struct aa_policy *policy)
154 {
155         /* still contains profiles -- invalid */
156         if (on_list_rcu(&policy->profiles)) {
157                 AA_ERROR("%s: internal error, "
158                          "policy '%s' still contains profiles\n",
159                          __func__, policy->name);
160                 BUG();
161         }
162         if (on_list_rcu(&policy->list)) {
163                 AA_ERROR("%s: internal error, policy '%s' still on list\n",
164                          __func__, policy->name);
165                 BUG();
166         }
167 
168         /* don't free name as its a subset of hname */
169         kzfree(policy->hname);
170 }
171 
172 /**
173  * __policy_find - find a policy by @name on a policy list
174  * @head: list to search  (NOT NULL)
175  * @name: name to search for  (NOT NULL)
176  *
177  * Requires: rcu_read_lock be held
178  *
179  * Returns: unrefcounted policy that match @name or NULL if not found
180  */
181 static struct aa_policy *__policy_find(struct list_head *head, const char *name)
182 {
183         struct aa_policy *policy;
184 
185         list_for_each_entry_rcu(policy, head, list) {
186                 if (!strcmp(policy->name, name))
187                         return policy;
188         }
189         return NULL;
190 }
191 
192 /**
193  * __policy_strn_find - find a policy that's name matches @len chars of @str
194  * @head: list to search  (NOT NULL)
195  * @str: string to search for  (NOT NULL)
196  * @len: length of match required
197  *
198  * Requires: rcu_read_lock be held
199  *
200  * Returns: unrefcounted policy that match @str or NULL if not found
201  *
202  * if @len == strlen(@strlen) then this is equiv to __policy_find
203  * other wise it allows searching for policy by a partial match of name
204  */
205 static struct aa_policy *__policy_strn_find(struct list_head *head,
206                                             const char *str, int len)
207 {
208         struct aa_policy *policy;
209 
210         list_for_each_entry_rcu(policy, head, list) {
211                 if (aa_strneq(policy->name, str, len))
212                         return policy;
213         }
214 
215         return NULL;
216 }
217 
218 /*
219  * Routines for AppArmor namespaces
220  */
221 
222 static const char *hidden_ns_name = "---";
223 /**
224  * aa_ns_visible - test if @view is visible from @curr
225  * @curr: namespace to treat as the parent (NOT NULL)
226  * @view:  namespace to test if visible from @curr (NOT NULL)
227  *
228  * Returns: true if @view is visible from @curr else false
229  */
230 bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view)
231 {
232         if (curr == view)
233                 return true;
234 
235         for ( ; view; view = view->parent) {
236                 if (view->parent == curr)
237                         return true;
238         }
239         return false;
240 }
241 
242 /**
243  * aa_na_name - Find the ns name to display for @view from @curr
244  * @curr - current namespace (NOT NULL)
245  * @view - namespace attempting to view (NOT NULL)
246  *
247  * Returns: name of @view visible from @curr
248  */
249 const char *aa_ns_name(struct aa_namespace *curr, struct aa_namespace *view)
250 {
251         /* if view == curr then the namespace name isn't displayed */
252         if (curr == view)
253                 return "";
254 
255         if (aa_ns_visible(curr, view)) {
256                 /* at this point if a ns is visible it is in a view ns
257                  * thus the curr ns.hname is a prefix of its name.
258                  * Only output the virtualized portion of the name
259                  * Add + 2 to skip over // separating curr hname prefix
260                  * from the visible tail of the views hname
261                  */
262                 return view->base.hname + strlen(curr->base.hname) + 2;
263         } else
264                 return hidden_ns_name;
265 }
266 
267 /**
268  * alloc_namespace - allocate, initialize and return a new namespace
269  * @prefix: parent namespace name (MAYBE NULL)
270  * @name: a preallocated name  (NOT NULL)
271  *
272  * Returns: refcounted namespace or NULL on failure.
273  */
274 static struct aa_namespace *alloc_namespace(const char *prefix,
275                                             const char *name)
276 {
277         struct aa_namespace *ns;
278 
279         ns = kzalloc(sizeof(*ns), GFP_KERNEL);
280         AA_DEBUG("%s(%p)\n", __func__, ns);
281         if (!ns)
282                 return NULL;
283         if (!policy_init(&ns->base, prefix, name))
284                 goto fail_ns;
285 
286         INIT_LIST_HEAD(&ns->sub_ns);
287         mutex_init(&ns->lock);
288 
289         /* released by free_namespace */
290         ns->unconfined = aa_alloc_profile("unconfined");
291         if (!ns->unconfined)
292                 goto fail_unconfined;
293 
294         ns->unconfined->flags = PFLAG_IX_ON_NAME_ERROR |
295                 PFLAG_IMMUTABLE | PFLAG_NS_COUNT;
296         ns->unconfined->mode = APPARMOR_UNCONFINED;
297 
298         /* ns and ns->unconfined share ns->unconfined refcount */
299         ns->unconfined->ns = ns;
300 
301         atomic_set(&ns->uniq_null, 0);
302 
303         return ns;
304 
305 fail_unconfined:
306         kzfree(ns->base.hname);
307 fail_ns:
308         kzfree(ns);
309         return NULL;
310 }
311 
312 /**
313  * free_namespace - free a profile namespace
314  * @ns: the namespace to free  (MAYBE NULL)
315  *
316  * Requires: All references to the namespace must have been put, if the
317  *           namespace was referenced by a profile confining a task,
318  */
319 static void free_namespace(struct aa_namespace *ns)
320 {
321         if (!ns)
322                 return;
323 
324         policy_destroy(&ns->base);
325         aa_put_namespace(ns->parent);
326 
327         ns->unconfined->ns = NULL;
328         aa_free_profile(ns->unconfined);
329         kzfree(ns);
330 }
331 
332 /**
333  * __aa_find_namespace - find a namespace on a list by @name
334  * @head: list to search for namespace on  (NOT NULL)
335  * @name: name of namespace to look for  (NOT NULL)
336  *
337  * Returns: unrefcounted namespace
338  *
339  * Requires: rcu_read_lock be held
340  */
341 static struct aa_namespace *__aa_find_namespace(struct list_head *head,
342                                                 const char *name)
343 {
344         return (struct aa_namespace *)__policy_find(head, name);
345 }
346 
347 /**
348  * aa_find_namespace  -  look up a profile namespace on the namespace list
349  * @root: namespace to search in  (NOT NULL)
350  * @name: name of namespace to find  (NOT NULL)
351  *
352  * Returns: a refcounted namespace on the list, or NULL if no namespace
353  *          called @name exists.
354  *
355  * refcount released by caller
356  */
357 struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
358                                        const char *name)
359 {
360         struct aa_namespace *ns = NULL;
361 
362         rcu_read_lock();
363         ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name));
364         rcu_read_unlock();
365 
366         return ns;
367 }
368 
369 /**
370  * aa_prepare_namespace - find an existing or create a new namespace of @name
371  * @name: the namespace to find or add  (MAYBE NULL)
372  *
373  * Returns: refcounted namespace or NULL if failed to create one
374  */
375 static struct aa_namespace *aa_prepare_namespace(const char *name)
376 {
377         struct aa_namespace *ns, *root;
378 
379         root = aa_current_profile()->ns;
380 
381         mutex_lock(&root->lock);
382 
383         /* if name isn't specified the profile is loaded to the current ns */
384         if (!name) {
385                 /* released by caller */
386                 ns = aa_get_namespace(root);
387                 goto out;
388         }
389 
390         /* try and find the specified ns and if it doesn't exist create it */
391         /* released by caller */
392         ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name));
393         if (!ns) {
394                 ns = alloc_namespace(root->base.hname, name);
395                 if (!ns)
396                         goto out;
397                 if (__aa_fs_namespace_mkdir(ns, ns_subns_dir(root), name)) {
398                         AA_ERROR("Failed to create interface for ns %s\n",
399                                  ns->base.name);
400                         free_namespace(ns);
401                         ns = NULL;
402                         goto out;
403                 }
404                 ns->parent = aa_get_namespace(root);
405                 list_add_rcu(&ns->base.list, &root->sub_ns);
406                 /* add list ref */
407                 aa_get_namespace(ns);
408         }
409 out:
410         mutex_unlock(&root->lock);
411 
412         /* return ref */
413         return ns;
414 }
415 
416 /**
417  * __list_add_profile - add a profile to a list
418  * @list: list to add it to  (NOT NULL)
419  * @profile: the profile to add  (NOT NULL)
420  *
421  * refcount @profile, should be put by __list_remove_profile
422  *
423  * Requires: namespace lock be held, or list not be shared
424  */
425 static void __list_add_profile(struct list_head *list,
426                                struct aa_profile *profile)
427 {
428         list_add_rcu(&profile->base.list, list);
429         /* get list reference */
430         aa_get_profile(profile);
431 }
432 
433 /**
434  * __list_remove_profile - remove a profile from the list it is on
435  * @profile: the profile to remove  (NOT NULL)
436  *
437  * remove a profile from the list, warning generally removal should
438  * be done with __replace_profile as most profile removals are
439  * replacements to the unconfined profile.
440  *
441  * put @profile list refcount
442  *
443  * Requires: namespace lock be held, or list not have been live
444  */
445 static void __list_remove_profile(struct aa_profile *profile)
446 {
447         list_del_rcu(&profile->base.list);
448         aa_put_profile(profile);
449 }
450 
451 static void __profile_list_release(struct list_head *head);
452 
453 /**
454  * __remove_profile - remove old profile, and children
455  * @profile: profile to be replaced  (NOT NULL)
456  *
457  * Requires: namespace list lock be held, or list not be shared
458  */
459 static void __remove_profile(struct aa_profile *profile)
460 {
461         /* release any children lists first */
462         __profile_list_release(&profile->base.profiles);
463         /* released by free_profile */
464         __aa_update_replacedby(profile, profile->ns->unconfined);
465         __aa_fs_profile_rmdir(profile);
466         __list_remove_profile(profile);
467 }
468 
469 /**
470  * __profile_list_release - remove all profiles on the list and put refs
471  * @head: list of profiles  (NOT NULL)
472  *
473  * Requires: namespace lock be held
474  */
475 static void __profile_list_release(struct list_head *head)
476 {
477         struct aa_profile *profile, *tmp;
478         list_for_each_entry_safe(profile, tmp, head, base.list)
479                 __remove_profile(profile);
480 }
481 
482 static void __ns_list_release(struct list_head *head);
483 
484 /**
485  * destroy_namespace - remove everything contained by @ns
486  * @ns: namespace to have it contents removed  (NOT NULL)
487  */
488 static void destroy_namespace(struct aa_namespace *ns)
489 {
490         if (!ns)
491                 return;
492 
493         mutex_lock(&ns->lock);
494         /* release all profiles in this namespace */
495         __profile_list_release(&ns->base.profiles);
496 
497         /* release all sub namespaces */
498         __ns_list_release(&ns->sub_ns);
499 
500         if (ns->parent)
501                 __aa_update_replacedby(ns->unconfined, ns->parent->unconfined);
502         __aa_fs_namespace_rmdir(ns);
503         mutex_unlock(&ns->lock);
504 }
505 
506 /**
507  * __remove_namespace - remove a namespace and all its children
508  * @ns: namespace to be removed  (NOT NULL)
509  *
510  * Requires: ns->parent->lock be held and ns removed from parent.
511  */
512 static void __remove_namespace(struct aa_namespace *ns)
513 {
514         /* remove ns from namespace list */
515         list_del_rcu(&ns->base.list);
516         destroy_namespace(ns);
517         aa_put_namespace(ns);
518 }
519 
520 /**
521  * __ns_list_release - remove all profile namespaces on the list put refs
522  * @head: list of profile namespaces  (NOT NULL)
523  *
524  * Requires: namespace lock be held
525  */
526 static void __ns_list_release(struct list_head *head)
527 {
528         struct aa_namespace *ns, *tmp;
529         list_for_each_entry_safe(ns, tmp, head, base.list)
530                 __remove_namespace(ns);
531 
532 }
533 
534 /**
535  * aa_alloc_root_ns - allocate the root profile namespace
536  *
537  * Returns: %0 on success else error
538  *
539  */
540 int __init aa_alloc_root_ns(void)
541 {
542         /* released by aa_free_root_ns - used as list ref*/
543         root_ns = alloc_namespace(NULL, "root");
544         if (!root_ns)
545                 return -ENOMEM;
546 
547         return 0;
548 }
549 
550  /**
551   * aa_free_root_ns - free the root profile namespace
552   */
553 void __init aa_free_root_ns(void)
554  {
555          struct aa_namespace *ns = root_ns;
556          root_ns = NULL;
557 
558          destroy_namespace(ns);
559          aa_put_namespace(ns);
560 }
561 
562 
563 static void free_replacedby(struct aa_replacedby *r)
564 {
565         if (r) {
566                 /* r->profile will not be updated any more as r is dead */
567                 aa_put_profile(rcu_dereference_protected(r->profile, true));
568                 kzfree(r);
569         }
570 }
571 
572 
573 void aa_free_replacedby_kref(struct kref *kref)
574 {
575         struct aa_replacedby *r = container_of(kref, struct aa_replacedby,
576                                                count);
577         free_replacedby(r);
578 }
579 
580 /**
581  * aa_free_profile - free a profile
582  * @profile: the profile to free  (MAYBE NULL)
583  *
584  * Free a profile, its hats and null_profile. All references to the profile,
585  * its hats and null_profile must have been put.
586  *
587  * If the profile was referenced from a task context, free_profile() will
588  * be called from an rcu callback routine, so we must not sleep here.
589  */
590 void aa_free_profile(struct aa_profile *profile)
591 {
592         AA_DEBUG("%s(%p)\n", __func__, profile);
593 
594         if (!profile)
595                 return;
596 
597         /* free children profiles */
598         policy_destroy(&profile->base);
599         aa_put_profile(rcu_access_pointer(profile->parent));
600 
601         aa_put_namespace(profile->ns);
602         kzfree(profile->rename);
603 
604         aa_free_file_rules(&profile->file);
605         aa_free_cap_rules(&profile->caps);
606         aa_free_rlimit_rules(&profile->rlimits);
607 
608         kzfree(profile->dirname);
609         aa_put_dfa(profile->xmatch);
610         aa_put_dfa(profile->policy.dfa);
611         aa_put_replacedby(profile->replacedby);
612 
613         kzfree(profile->hash);
614         kzfree(profile);
615 }
616 
617 /**
618  * aa_free_profile_rcu - free aa_profile by rcu (called by aa_free_profile_kref)
619  * @head: rcu_head callback for freeing of a profile  (NOT NULL)
620  */
621 static void aa_free_profile_rcu(struct rcu_head *head)
622 {
623         struct aa_profile *p = container_of(head, struct aa_profile, rcu);
624         if (p->flags & PFLAG_NS_COUNT)
625                 free_namespace(p->ns);
626         else
627                 aa_free_profile(p);
628 }
629 
630 /**
631  * aa_free_profile_kref - free aa_profile by kref (called by aa_put_profile)
632  * @kr: kref callback for freeing of a profile  (NOT NULL)
633  */
634 void aa_free_profile_kref(struct kref *kref)
635 {
636         struct aa_profile *p = container_of(kref, struct aa_profile, count);
637         call_rcu(&p->rcu, aa_free_profile_rcu);
638 }
639 
640 /**
641  * aa_alloc_profile - allocate, initialize and return a new profile
642  * @hname: name of the profile  (NOT NULL)
643  *
644  * Returns: refcount profile or NULL on failure
645  */
646 struct aa_profile *aa_alloc_profile(const char *hname)
647 {
648         struct aa_profile *profile;
649 
650         /* freed by free_profile - usually through aa_put_profile */
651         profile = kzalloc(sizeof(*profile), GFP_KERNEL);
652         if (!profile)
653                 return NULL;
654 
655         profile->replacedby = kzalloc(sizeof(struct aa_replacedby), GFP_KERNEL);
656         if (!profile->replacedby)
657                 goto fail;
658         kref_init(&profile->replacedby->count);
659 
660         if (!policy_init(&profile->base, NULL, hname))
661                 goto fail;
662         kref_init(&profile->count);
663 
664         /* refcount released by caller */
665         return profile;
666 
667 fail:
668         kzfree(profile->replacedby);
669         kzfree(profile);
670 
671         return NULL;
672 }
673 
674 /**
675  * aa_new_null_profile - create a new null-X learning profile
676  * @parent: profile that caused this profile to be created (NOT NULL)
677  * @hat: true if the null- learning profile is a hat
678  *
679  * Create a null- complain mode profile used in learning mode.  The name of
680  * the profile is unique and follows the format of parent//null-<uniq>.
681  *
682  * null profiles are added to the profile list but the list does not
683  * hold a count on them so that they are automatically released when
684  * not in use.
685  *
686  * Returns: new refcounted profile else NULL on failure
687  */
688 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat)
689 {
690         struct aa_profile *profile = NULL;
691         char *name;
692         int uniq = atomic_inc_return(&parent->ns->uniq_null);
693 
694         /* freed below */
695         name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, GFP_KERNEL);
696         if (!name)
697                 goto fail;
698         sprintf(name, "%s//null-%x", parent->base.hname, uniq);
699 
700         profile = aa_alloc_profile(name);
701         kfree(name);
702         if (!profile)
703                 goto fail;
704 
705         profile->mode = APPARMOR_COMPLAIN;
706         profile->flags = PFLAG_NULL;
707         if (hat)
708                 profile->flags |= PFLAG_HAT;
709 
710         /* released on free_profile */
711         rcu_assign_pointer(profile->parent, aa_get_profile(parent));
712         profile->ns = aa_get_namespace(parent->ns);
713 
714         mutex_lock(&profile->ns->lock);
715         __list_add_profile(&parent->base.profiles, profile);
716         mutex_unlock(&profile->ns->lock);
717 
718         /* refcount released by caller */
719         return profile;
720 
721 fail:
722         return NULL;
723 }
724 
725 /* TODO: profile accounting - setup in remove */
726 
727 /**
728  * __find_child - find a profile on @head list with a name matching @name
729  * @head: list to search  (NOT NULL)
730  * @name: name of profile (NOT NULL)
731  *
732  * Requires: rcu_read_lock be held
733  *
734  * Returns: unrefcounted profile ptr, or NULL if not found
735  */
736 static struct aa_profile *__find_child(struct list_head *head, const char *name)
737 {
738         return (struct aa_profile *)__policy_find(head, name);
739 }
740 
741 /**
742  * __strn_find_child - find a profile on @head list using substring of @name
743  * @head: list to search  (NOT NULL)
744  * @name: name of profile (NOT NULL)
745  * @len: length of @name substring to match
746  *
747  * Requires: rcu_read_lock be held
748  *
749  * Returns: unrefcounted profile ptr, or NULL if not found
750  */
751 static struct aa_profile *__strn_find_child(struct list_head *head,
752                                             const char *name, int len)
753 {
754         return (struct aa_profile *)__policy_strn_find(head, name, len);
755 }
756 
757 /**
758  * aa_find_child - find a profile by @name in @parent
759  * @parent: profile to search  (NOT NULL)
760  * @name: profile name to search for  (NOT NULL)
761  *
762  * Returns: a refcounted profile or NULL if not found
763  */
764 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name)
765 {
766         struct aa_profile *profile;
767 
768         rcu_read_lock();
769         do {
770                 profile = __find_child(&parent->base.profiles, name);
771         } while (profile && !aa_get_profile_not0(profile));
772         rcu_read_unlock();
773 
774         /* refcount released by caller */
775         return profile;
776 }
777 
778 /**
779  * __lookup_parent - lookup the parent of a profile of name @hname
780  * @ns: namespace to lookup profile in  (NOT NULL)
781  * @hname: hierarchical profile name to find parent of  (NOT NULL)
782  *
783  * Lookups up the parent of a fully qualified profile name, the profile
784  * that matches hname does not need to exist, in general this
785  * is used to load a new profile.
786  *
787  * Requires: rcu_read_lock be held
788  *
789  * Returns: unrefcounted policy or NULL if not found
790  */
791 static struct aa_policy *__lookup_parent(struct aa_namespace *ns,
792                                          const char *hname)
793 {
794         struct aa_policy *policy;
795         struct aa_profile *profile = NULL;
796         char *split;
797 
798         policy = &ns->base;
799 
800         for (split = strstr(hname, "//"); split;) {
801                 profile = __strn_find_child(&policy->profiles, hname,
802                                             split - hname);
803                 if (!profile)
804                         return NULL;
805                 policy = &profile->base;
806                 hname = split + 2;
807                 split = strstr(hname, "//");
808         }
809         if (!profile)
810                 return &ns->base;
811         return &profile->base;
812 }
813 
814 /**
815  * __lookup_profile - lookup the profile matching @hname
816  * @base: base list to start looking up profile name from  (NOT NULL)
817  * @hname: hierarchical profile name  (NOT NULL)
818  *
819  * Requires: rcu_read_lock be held
820  *
821  * Returns: unrefcounted profile pointer or NULL if not found
822  *
823  * Do a relative name lookup, recursing through profile tree.
824  */
825 static struct aa_profile *__lookup_profile(struct aa_policy *base,
826                                            const char *hname)
827 {
828         struct aa_profile *profile = NULL;
829         char *split;
830 
831         for (split = strstr(hname, "//"); split;) {
832                 profile = __strn_find_child(&base->profiles, hname,
833                                             split - hname);
834                 if (!profile)
835                         return NULL;
836 
837                 base = &profile->base;
838                 hname = split + 2;
839                 split = strstr(hname, "//");
840         }
841 
842         profile = __find_child(&base->profiles, hname);
843 
844         return profile;
845 }
846 
847 /**
848  * aa_lookup_profile - find a profile by its full or partial name
849  * @ns: the namespace to start from (NOT NULL)
850  * @hname: name to do lookup on.  Does not contain namespace prefix (NOT NULL)
851  *
852  * Returns: refcounted profile or NULL if not found
853  */
854 struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *hname)
855 {
856         struct aa_profile *profile;
857 
858         rcu_read_lock();
859         do {
860                 profile = __lookup_profile(&ns->base, hname);
861         } while (profile && !aa_get_profile_not0(profile));
862         rcu_read_unlock();
863 
864         /* the unconfined profile is not in the regular profile list */
865         if (!profile && strcmp(hname, "unconfined") == 0)
866                 profile = aa_get_newest_profile(ns->unconfined);
867 
868         /* refcount released by caller */
869         return profile;
870 }
871 
872 /**
873  * replacement_allowed - test to see if replacement is allowed
874  * @profile: profile to test if it can be replaced  (MAYBE NULL)
875  * @noreplace: true if replacement shouldn't be allowed but addition is okay
876  * @info: Returns - info about why replacement failed (NOT NULL)
877  *
878  * Returns: %0 if replacement allowed else error code
879  */
880 static int replacement_allowed(struct aa_profile *profile, int noreplace,
881                                const char **info)
882 {
883         if (profile) {
884                 if (profile->flags & PFLAG_IMMUTABLE) {
885                         *info = "cannot replace immutible profile";
886                         return -EPERM;
887                 } else if (noreplace) {
888                         *info = "profile already exists";
889                         return -EEXIST;
890                 }
891         }
892         return 0;
893 }
894 
895 /**
896  * aa_audit_policy - Do auditing of policy changes
897  * @op: policy operation being performed
898  * @gfp: memory allocation flags
899  * @name: name of profile being manipulated (NOT NULL)
900  * @info: any extra information to be audited (MAYBE NULL)
901  * @error: error code
902  *
903  * Returns: the error to be returned after audit is done
904  */
905 static int audit_policy(int op, gfp_t gfp, const char *name, const char *info,
906                         int error)
907 {
908         struct common_audit_data sa;
909         struct apparmor_audit_data aad = {0,};
910         sa.type = LSM_AUDIT_DATA_NONE;
911         sa.aad = &aad;
912         aad.op = op;
913         aad.name = name;
914         aad.info = info;
915         aad.error = error;
916 
917         return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp,
918                         &sa, NULL);
919 }
920 
921 bool policy_view_capable(void)
922 {
923         struct user_namespace *user_ns = current_user_ns();
924         bool response = false;
925 
926         if (ns_capable(user_ns, CAP_MAC_ADMIN))
927                 response = true;
928 
929         return response;
930 }
931 
932 bool policy_admin_capable(void)
933 {
934         return policy_view_capable() && !aa_g_lock_policy;
935 }
936 
937 /**
938  * aa_may_manage_policy - can the current task manage policy
939  * @op: the policy manipulation operation being done
940  *
941  * Returns: true if the task is allowed to manipulate policy
942  */
943 bool aa_may_manage_policy(int op)
944 {
945         /* check if loading policy is locked out */
946         if (aa_g_lock_policy) {
947                 audit_policy(op, GFP_KERNEL, NULL, "policy_locked", -EACCES);
948                 return 0;
949         }
950 
951         if (!policy_admin_capable()) {
952                 audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES);
953                 return 0;
954         }
955 
956         return 1;
957 }
958 
959 static struct aa_profile *__list_lookup_parent(struct list_head *lh,
960                                                struct aa_profile *profile)
961 {
962         const char *base = hname_tail(profile->base.hname);
963         long len = base - profile->base.hname;
964         struct aa_load_ent *ent;
965 
966         /* parent won't have trailing // so remove from len */
967         if (len <= 2)
968                 return NULL;
969         len -= 2;
970 
971         list_for_each_entry(ent, lh, list) {
972                 if (ent->new == profile)
973                         continue;
974                 if (strncmp(ent->new->base.hname, profile->base.hname, len) ==
975                     0 && ent->new->base.hname[len] == 0)
976                         return ent->new;
977         }
978 
979         return NULL;
980 }
981 
982 /**
983  * __replace_profile - replace @old with @new on a list
984  * @old: profile to be replaced  (NOT NULL)
985  * @new: profile to replace @old with  (NOT NULL)
986  * @share_replacedby: transfer @old->replacedby to @new
987  *
988  * Will duplicate and refcount elements that @new inherits from @old
989  * and will inherit @old children.
990  *
991  * refcount @new for list, put @old list refcount
992  *
993  * Requires: namespace list lock be held, or list not be shared
994  */
995 static void __replace_profile(struct aa_profile *old, struct aa_profile *new,
996                               bool share_replacedby)
997 {
998         struct aa_profile *child, *tmp;
999 
1000         if (!list_empty(&old->base.profiles)) {
1001                 LIST_HEAD(lh);
1002                 list_splice_init_rcu(&old->base.profiles, &lh, synchronize_rcu);
1003 
1004                 list_for_each_entry_safe(child, tmp, &lh, base.list) {
1005                         struct aa_profile *p;
1006 
1007                         list_del_init(&child->base.list);
1008                         p = __find_child(&new->base.profiles, child->base.name);
1009                         if (p) {
1010                                 /* @p replaces @child  */
1011                                 __replace_profile(child, p, share_replacedby);
1012                                 continue;
1013                         }
1014 
1015                         /* inherit @child and its children */
1016                         /* TODO: update hname of inherited children */
1017                         /* list refcount transferred to @new */
1018                         p = aa_deref_parent(child);
1019                         rcu_assign_pointer(child->parent, aa_get_profile(new));
1020                         list_add_rcu(&child->base.list, &new->base.profiles);
1021                         aa_put_profile(p);
1022                 }
1023         }
1024 
1025         if (!rcu_access_pointer(new->parent)) {
1026                 struct aa_profile *parent = aa_deref_parent(old);
1027                 rcu_assign_pointer(new->parent, aa_get_profile(parent));
1028         }
1029         __aa_update_replacedby(old, new);
1030         if (share_replacedby) {
1031                 aa_put_replacedby(new->replacedby);
1032                 new->replacedby = aa_get_replacedby(old->replacedby);
1033         } else if (!rcu_access_pointer(new->replacedby->profile))
1034                 /* aafs interface uses replacedby */
1035                 rcu_assign_pointer(new->replacedby->profile,
1036                                    aa_get_profile(new));
1037         __aa_fs_profile_migrate_dents(old, new);
1038 
1039         if (list_empty(&new->base.list)) {
1040                 /* new is not on a list already */
1041                 list_replace_rcu(&old->base.list, &new->base.list);
1042                 aa_get_profile(new);
1043                 aa_put_profile(old);
1044         } else
1045                 __list_remove_profile(old);
1046 }
1047 
1048 /**
1049  * __lookup_replace - lookup replacement information for a profile
1050  * @ns - namespace the lookup occurs in
1051  * @hname - name of profile to lookup
1052  * @noreplace - true if not replacing an existing profile
1053  * @p - Returns: profile to be replaced
1054  * @info - Returns: info string on why lookup failed
1055  *
1056  * Returns: profile to replace (no ref) on success else ptr error
1057  */
1058 static int __lookup_replace(struct aa_namespace *ns, const char *hname,
1059                             bool noreplace, struct aa_profile **p,
1060                             const char **info)
1061 {
1062         *p = aa_get_profile(__lookup_profile(&ns->base, hname));
1063         if (*p) {
1064                 int error = replacement_allowed(*p, noreplace, info);
1065                 if (error) {
1066                         *info = "profile can not be replaced";
1067                         return error;
1068                 }
1069         }
1070 
1071         return 0;
1072 }
1073 
1074 /**
1075  * aa_replace_profiles - replace profile(s) on the profile list
1076  * @udata: serialized data stream  (NOT NULL)
1077  * @size: size of the serialized data stream
1078  * @noreplace: true if only doing addition, no replacement allowed
1079  *
1080  * unpack and replace a profile on the profile list and uses of that profile
1081  * by any aa_task_cxt.  If the profile does not exist on the profile list
1082  * it is added.
1083  *
1084  * Returns: size of data consumed else error code on failure.
1085  */
1086 ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace)
1087 {
1088         const char *ns_name, *info = NULL;
1089         struct aa_namespace *ns = NULL;
1090         struct aa_load_ent *ent, *tmp;
1091         int op = OP_PROF_REPL;
1092         ssize_t error;
1093         LIST_HEAD(lh);
1094 
1095         /* released below */
1096         error = aa_unpack(udata, size, &lh, &ns_name);
1097         if (error)
1098                 goto out;
1099 
1100         /* released below */
1101         ns = aa_prepare_namespace(ns_name);
1102         if (!ns) {
1103                 error = audit_policy(op, GFP_KERNEL, ns_name,
1104                                      "failed to prepare namespace", -ENOMEM);
1105                 goto free;
1106         }
1107 
1108         mutex_lock(&ns->lock);
1109         /* setup parent and ns info */
1110         list_for_each_entry(ent, &lh, list) {
1111                 struct aa_policy *policy;
1112                 error = __lookup_replace(ns, ent->new->base.hname, noreplace,
1113                                          &ent->old, &info);
1114                 if (error)
1115                         goto fail_lock;
1116 
1117                 if (ent->new->rename) {
1118                         error = __lookup_replace(ns, ent->new->rename,
1119                                                  noreplace, &ent->rename,
1120                                                  &info);
1121                         if (error)
1122                                 goto fail_lock;
1123                 }
1124 
1125                 /* released when @new is freed */
1126                 ent->new->ns = aa_get_namespace(ns);
1127 
1128                 if (ent->old || ent->rename)
1129                         continue;
1130 
1131                 /* no ref on policy only use inside lock */
1132                 policy = __lookup_parent(ns, ent->new->base.hname);
1133                 if (!policy) {
1134                         struct aa_profile *p;
1135                         p = __list_lookup_parent(&lh, ent->new);
1136                         if (!p) {
1137                                 error = -ENOENT;
1138                                 info = "parent does not exist";
1139                                 goto fail_lock;
1140                         }
1141                         rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
1142                 } else if (policy != &ns->base) {
1143                         /* released on profile replacement or free_profile */
1144                         struct aa_profile *p = (struct aa_profile *) policy;
1145                         rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
1146                 }
1147         }
1148 
1149         /* create new fs entries for introspection if needed */
1150         list_for_each_entry(ent, &lh, list) {
1151                 if (ent->old) {
1152                         /* inherit old interface files */
1153 
1154                         /* if (ent->rename)
1155                                 TODO: support rename */
1156                 /* } else if (ent->rename) {
1157                         TODO: support rename */
1158                 } else {
1159                         struct dentry *parent;
1160                         if (rcu_access_pointer(ent->new->parent)) {
1161                                 struct aa_profile *p;
1162                                 p = aa_deref_parent(ent->new);
1163                                 parent = prof_child_dir(p);
1164                         } else
1165                                 parent = ns_subprofs_dir(ent->new->ns);
1166                         error = __aa_fs_profile_mkdir(ent->new, parent);
1167                 }
1168 
1169                 if (error) {
1170                         info = "failed to create ";
1171                         goto fail_lock;
1172                 }
1173         }
1174 
1175         /* Done with checks that may fail - do actual replacement */
1176         list_for_each_entry_safe(ent, tmp, &lh, list) {
1177                 list_del_init(&ent->list);
1178                 op = (!ent->old && !ent->rename) ? OP_PROF_LOAD : OP_PROF_REPL;
1179 
1180                 audit_policy(op, GFP_ATOMIC, ent->new->base.hname, NULL, error);
1181 
1182                 if (ent->old) {
1183                         __replace_profile(ent->old, ent->new, 1);
1184                         if (ent->rename) {
1185                                 /* aafs interface uses replacedby */
1186                                 struct aa_replacedby *r = ent->new->replacedby;
1187                                 rcu_assign_pointer(r->profile,
1188                                                    aa_get_profile(ent->new));
1189                                 __replace_profile(ent->rename, ent->new, 0);
1190                         }
1191                 } else if (ent->rename) {
1192                         /* aafs interface uses replacedby */
1193                         rcu_assign_pointer(ent->new->replacedby->profile,
1194                                            aa_get_profile(ent->new));
1195                         __replace_profile(ent->rename, ent->new, 0);
1196                 } else if (ent->new->parent) {
1197                         struct aa_profile *parent, *newest;
1198                         parent = aa_deref_parent(ent->new);
1199                         newest = aa_get_newest_profile(parent);
1200 
1201                         /* parent replaced in this atomic set? */
1202                         if (newest != parent) {
1203                                 aa_get_profile(newest);
1204                                 rcu_assign_pointer(ent->new->parent, newest);
1205                                 aa_put_profile(parent);
1206                         }
1207                         /* aafs interface uses replacedby */
1208                         rcu_assign_pointer(ent->new->replacedby->profile,
1209                                            aa_get_profile(ent->new));
1210                         __list_add_profile(&newest->base.profiles, ent->new);
1211                         aa_put_profile(newest);
1212                 } else {
1213                         /* aafs interface uses replacedby */
1214                         rcu_assign_pointer(ent->new->replacedby->profile,
1215                                            aa_get_profile(ent->new));
1216                         __list_add_profile(&ns->base.profiles, ent->new);
1217                 }
1218                 aa_load_ent_free(ent);
1219         }
1220         mutex_unlock(&ns->lock);
1221 
1222 out:
1223         aa_put_namespace(ns);
1224 
1225         if (error)
1226                 return error;
1227         return size;
1228 
1229 fail_lock:
1230         mutex_unlock(&ns->lock);
1231 
1232         /* audit cause of failure */
1233         op = (!ent->old) ? OP_PROF_LOAD : OP_PROF_REPL;
1234         audit_policy(op, GFP_KERNEL, ent->new->base.hname, info, error);
1235         /* audit status that rest of profiles in the atomic set failed too */
1236         info = "valid profile in failed atomic policy load";
1237         list_for_each_entry(tmp, &lh, list) {
1238                 if (tmp == ent) {
1239                         info = "unchecked profile in failed atomic policy load";
1240                         /* skip entry that caused failure */
1241                         continue;
1242                 }
1243                 op = (!ent->old) ? OP_PROF_LOAD : OP_PROF_REPL;
1244                 audit_policy(op, GFP_KERNEL, tmp->new->base.hname, info, error);
1245         }
1246 free:
1247         list_for_each_entry_safe(ent, tmp, &lh, list) {
1248                 list_del_init(&ent->list);
1249                 aa_load_ent_free(ent);
1250         }
1251 
1252         goto out;
1253 }
1254 
1255 /**
1256  * aa_remove_profiles - remove profile(s) from the system
1257  * @fqname: name of the profile or namespace to remove  (NOT NULL)
1258  * @size: size of the name
1259  *
1260  * Remove a profile or sub namespace from the current namespace, so that
1261  * they can not be found anymore and mark them as replaced by unconfined
1262  *
1263  * NOTE: removing confinement does not restore rlimits to preconfinemnet values
1264  *
1265  * Returns: size of data consume else error code if fails
1266  */
1267 ssize_t aa_remove_profiles(char *fqname, size_t size)
1268 {
1269         struct aa_namespace *root, *ns = NULL;
1270         struct aa_profile *profile = NULL;
1271         const char *name = fqname, *info = NULL;
1272         ssize_t error = 0;
1273 
1274         if (*fqname == 0) {
1275                 info = "no profile specified";
1276                 error = -ENOENT;
1277                 goto fail;
1278         }
1279 
1280         root = aa_current_profile()->ns;
1281 
1282         if (fqname[0] == ':') {
1283                 char *ns_name;
1284                 name = aa_split_fqname(fqname, &ns_name);
1285                 /* released below */
1286                 ns = aa_find_namespace(root, ns_name);
1287                 if (!ns) {
1288                         info = "namespace does not exist";
1289                         error = -ENOENT;
1290                         goto fail;
1291                 }
1292         } else
1293                 /* released below */
1294                 ns = aa_get_namespace(root);
1295 
1296         if (!name) {
1297                 /* remove namespace - can only happen if fqname[0] == ':' */
1298                 mutex_lock(&ns->parent->lock);
1299                 __remove_namespace(ns);
1300                 mutex_unlock(&ns->parent->lock);
1301         } else {
1302                 /* remove profile */
1303                 mutex_lock(&ns->lock);
1304                 profile = aa_get_profile(__lookup_profile(&ns->base, name));
1305                 if (!profile) {
1306                         error = -ENOENT;
1307                         info = "profile does not exist";
1308                         goto fail_ns_lock;
1309                 }
1310                 name = profile->base.hname;
1311                 __remove_profile(profile);
1312                 mutex_unlock(&ns->lock);
1313         }
1314 
1315         /* don't fail removal if audit fails */
1316         (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
1317         aa_put_namespace(ns);
1318         aa_put_profile(profile);
1319         return size;
1320 
1321 fail_ns_lock:
1322         mutex_unlock(&ns->lock);
1323         aa_put_namespace(ns);
1324 
1325 fail:
1326         (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
1327         return error;
1328 }
1329 

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