1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * AppArmor security module
4 *
5 * This file contains AppArmor policy manipulation functions
6 *
7 * Copyright (C) 1998-2008 Novell/SUSE
8 * Copyright 2009-2010 Canonical Ltd.
9 *
10 * AppArmor policy is based around profiles, which contain the rules a
11 * task is confined by. Every task in the system has a profile attached
12 * to it determined either by matching "unconfined" tasks against the
13 * visible set of profiles or by following a profiles attachment rules.
14 *
15 * Each profile exists in a profile namespace which is a container of
16 * visible profiles. Each namespace contains a special "unconfined" profile,
17 * which doesn't enforce any confinement on a task beyond DAC.
18 *
19 * Namespace and profile names can be written together in either
20 * of two syntaxes.
21 * :namespace:profile - used by kernel interfaces for easy detection
22 * namespace://profile - used by policy
23 *
24 * Profile names can not start with : or @ or ^ and may not contain \0
25 *
26 * Reserved profile names
27 * unconfined - special automatically generated unconfined profile
28 * inherit - special name to indicate profile inheritance
29 * null-XXXX-YYYY - special automatically generated learning profiles
30 *
31 * Namespace names may not start with / or @ and may not contain \0 or :
32 * Reserved namespace names
33 * user-XXXX - user defined profiles
34 *
35 * a // in a profile or namespace name indicates a hierarchical name with the
36 * name before the // being the parent and the name after the child.
37 *
38 * Profile and namespace hierarchies serve two different but similar purposes.
39 * The namespace contains the set of visible profiles that are considered
40 * for attachment. The hierarchy of namespaces allows for virtualizing
41 * the namespace so that for example a chroot can have its own set of profiles
42 * which may define some local user namespaces.
43 * The profile hierarchy severs two distinct purposes,
44 * - it allows for sub profiles or hats, which allows an application to run
45 * subprograms under its own profile with different restriction than it
46 * self, and not have it use the system profile.
47 * eg. if a mail program starts an editor, the policy might make the
48 * restrictions tighter on the editor tighter than the mail program,
49 * and definitely different than general editor restrictions
50 * - it allows for binary hierarchy of profiles, so that execution history
51 * is preserved. This feature isn't exploited by AppArmor reference policy
52 * but is allowed. NOTE: this is currently suboptimal because profile
53 * aliasing is not currently implemented so that a profile for each
54 * level must be defined.
55 * eg. /bin/bash///bin/ls as a name would indicate /bin/ls was started
56 * from /bin/bash
57 *
58 * A profile or namespace name that can contain one or more // separators
59 * is referred to as an hname (hierarchical).
60 * eg. /bin/bash//bin/ls
61 *
62 * An fqname is a name that may contain both namespace and profile hnames.
63 * eg. :ns:/bin/bash//bin/ls
64 *
65 * NOTES:
66 * - locking of profile lists is currently fairly coarse. All profile
67 * lists within a namespace use the namespace lock.
68 * FIXME: move profile lists to using rcu_lists
69 */
70
71 #include <linux/slab.h>
72 #include <linux/spinlock.h>
73 #include <linux/string.h>
74 #include <linux/cred.h>
75 #include <linux/rculist.h>
76 #include <linux/user_namespace.h>
77
78 #include "include/apparmor.h"
79 #include "include/capability.h"
80 #include "include/cred.h"
81 #include "include/file.h"
82 #include "include/ipc.h"
83 #include "include/match.h"
84 #include "include/path.h"
85 #include "include/policy.h"
86 #include "include/policy_ns.h"
87 #include "include/policy_unpack.h"
88 #include "include/resource.h"
89
90 int unprivileged_userns_apparmor_policy = 1;
91 int aa_unprivileged_unconfined_restricted;
92
93 const char *const aa_profile_mode_names[] = {
94 "enforce",
95 "complain",
96 "kill",
97 "unconfined",
98 "user",
99 };
100
101
102 static void aa_free_pdb(struct aa_policydb *pdb)
103 {
104 if (pdb) {
105 aa_put_dfa(pdb->dfa);
106 if (pdb->perms)
107 kvfree(pdb->perms);
108 aa_free_str_table(&pdb->trans);
109 kfree(pdb);
110 }
111 }
112
113 /**
114 * aa_pdb_free_kref - free aa_policydb by kref (called by aa_put_pdb)
115 * @kref: kref callback for freeing of a dfa (NOT NULL)
116 */
117 void aa_pdb_free_kref(struct kref *kref)
118 {
119 struct aa_policydb *pdb = container_of(kref, struct aa_policydb, count);
120
121 aa_free_pdb(pdb);
122 }
123
124
125 struct aa_policydb *aa_alloc_pdb(gfp_t gfp)
126 {
127 struct aa_policydb *pdb = kzalloc(sizeof(struct aa_policydb), gfp);
128
129 if (!pdb)
130 return NULL;
131
132 kref_init(&pdb->count);
133
134 return pdb;
135 }
136
137
138 /**
139 * __add_profile - add a profiles to list and label tree
140 * @list: list to add it to (NOT NULL)
141 * @profile: the profile to add (NOT NULL)
142 *
143 * refcount @profile, should be put by __list_remove_profile
144 *
145 * Requires: namespace lock be held, or list not be shared
146 */
147 static void __add_profile(struct list_head *list, struct aa_profile *profile)
148 {
149 struct aa_label *l;
150
151 AA_BUG(!list);
152 AA_BUG(!profile);
153 AA_BUG(!profile->ns);
154 AA_BUG(!mutex_is_locked(&profile->ns->lock));
155
156 list_add_rcu(&profile->base.list, list);
157 /* get list reference */
158 aa_get_profile(profile);
159 l = aa_label_insert(&profile->ns->labels, &profile->label);
160 AA_BUG(l != &profile->label);
161 aa_put_label(l);
162 }
163
164 /**
165 * __list_remove_profile - remove a profile from the list it is on
166 * @profile: the profile to remove (NOT NULL)
167 *
168 * remove a profile from the list, warning generally removal should
169 * be done with __replace_profile as most profile removals are
170 * replacements to the unconfined profile.
171 *
172 * put @profile list refcount
173 *
174 * Requires: namespace lock be held, or list not have been live
175 */
176 static void __list_remove_profile(struct aa_profile *profile)
177 {
178 AA_BUG(!profile);
179 AA_BUG(!profile->ns);
180 AA_BUG(!mutex_is_locked(&profile->ns->lock));
181
182 list_del_rcu(&profile->base.list);
183 aa_put_profile(profile);
184 }
185
186 /**
187 * __remove_profile - remove old profile, and children
188 * @profile: profile to be replaced (NOT NULL)
189 *
190 * Requires: namespace list lock be held, or list not be shared
191 */
192 static void __remove_profile(struct aa_profile *profile)
193 {
194 AA_BUG(!profile);
195 AA_BUG(!profile->ns);
196 AA_BUG(!mutex_is_locked(&profile->ns->lock));
197
198 /* release any children lists first */
199 __aa_profile_list_release(&profile->base.profiles);
200 /* released by free_profile */
201 aa_label_remove(&profile->label);
202 __aafs_profile_rmdir(profile);
203 __list_remove_profile(profile);
204 }
205
206 /**
207 * __aa_profile_list_release - remove all profiles on the list and put refs
208 * @head: list of profiles (NOT NULL)
209 *
210 * Requires: namespace lock be held
211 */
212 void __aa_profile_list_release(struct list_head *head)
213 {
214 struct aa_profile *profile, *tmp;
215 list_for_each_entry_safe(profile, tmp, head, base.list)
216 __remove_profile(profile);
217 }
218
219 /**
220 * aa_free_data - free a data blob
221 * @ptr: data to free
222 * @arg: unused
223 */
224 static void aa_free_data(void *ptr, void *arg)
225 {
226 struct aa_data *data = ptr;
227
228 kvfree_sensitive(data->data, data->size);
229 kfree_sensitive(data->key);
230 kfree_sensitive(data);
231 }
232
233 static void free_attachment(struct aa_attachment *attach)
234 {
235 int i;
236
237 for (i = 0; i < attach->xattr_count; i++)
238 kfree_sensitive(attach->xattrs[i]);
239 kfree_sensitive(attach->xattrs);
240 aa_put_pdb(attach->xmatch);
241 }
242
243 static void free_ruleset(struct aa_ruleset *rules)
244 {
245 int i;
246
247 aa_put_pdb(rules->file);
248 aa_put_pdb(rules->policy);
249 aa_free_cap_rules(&rules->caps);
250 aa_free_rlimit_rules(&rules->rlimits);
251
252 for (i = 0; i < rules->secmark_count; i++)
253 kfree_sensitive(rules->secmark[i].label);
254 kfree_sensitive(rules->secmark);
255 kfree_sensitive(rules);
256 }
257
258 struct aa_ruleset *aa_alloc_ruleset(gfp_t gfp)
259 {
260 struct aa_ruleset *rules;
261
262 rules = kzalloc(sizeof(*rules), gfp);
263 if (rules)
264 INIT_LIST_HEAD(&rules->list);
265
266 return rules;
267 }
268
269 /**
270 * aa_free_profile - free a profile
271 * @profile: the profile to free (MAYBE NULL)
272 *
273 * Free a profile, its hats and null_profile. All references to the profile,
274 * its hats and null_profile must have been put.
275 *
276 * If the profile was referenced from a task context, free_profile() will
277 * be called from an rcu callback routine, so we must not sleep here.
278 */
279 void aa_free_profile(struct aa_profile *profile)
280 {
281 struct aa_ruleset *rule, *tmp;
282 struct rhashtable *rht;
283
284 AA_DEBUG("%s(%p)\n", __func__, profile);
285
286 if (!profile)
287 return;
288
289 /* free children profiles */
290 aa_policy_destroy(&profile->base);
291 aa_put_profile(rcu_access_pointer(profile->parent));
292
293 aa_put_ns(profile->ns);
294 kfree_sensitive(profile->rename);
295 kfree_sensitive(profile->disconnected);
296
297 free_attachment(&profile->attach);
298
299 /*
300 * at this point there are no tasks that can have a reference
301 * to rules
302 */
303 list_for_each_entry_safe(rule, tmp, &profile->rules, list) {
304 list_del_init(&rule->list);
305 free_ruleset(rule);
306 }
307 kfree_sensitive(profile->dirname);
308
309 if (profile->data) {
310 rht = profile->data;
311 profile->data = NULL;
312 rhashtable_free_and_destroy(rht, aa_free_data, NULL);
313 kfree_sensitive(rht);
314 }
315
316 kfree_sensitive(profile->hash);
317 aa_put_loaddata(profile->rawdata);
318 aa_label_destroy(&profile->label);
319
320 kfree_sensitive(profile);
321 }
322
323 /**
324 * aa_alloc_profile - allocate, initialize and return a new profile
325 * @hname: name of the profile (NOT NULL)
326 * @proxy: proxy to use OR null if to allocate a new one
327 * @gfp: allocation type
328 *
329 * Returns: refcount profile or NULL on failure
330 */
331 struct aa_profile *aa_alloc_profile(const char *hname, struct aa_proxy *proxy,
332 gfp_t gfp)
333 {
334 struct aa_profile *profile;
335 struct aa_ruleset *rules;
336
337 /* freed by free_profile - usually through aa_put_profile */
338 profile = kzalloc(struct_size(profile, label.vec, 2), gfp);
339 if (!profile)
340 return NULL;
341
342 if (!aa_policy_init(&profile->base, NULL, hname, gfp))
343 goto fail;
344 if (!aa_label_init(&profile->label, 1, gfp))
345 goto fail;
346
347 INIT_LIST_HEAD(&profile->rules);
348
349 /* allocate the first ruleset, but leave it empty */
350 rules = aa_alloc_ruleset(gfp);
351 if (!rules)
352 goto fail;
353 list_add(&rules->list, &profile->rules);
354
355 /* update being set needed by fs interface */
356 if (!proxy) {
357 proxy = aa_alloc_proxy(&profile->label, gfp);
358 if (!proxy)
359 goto fail;
360 } else
361 aa_get_proxy(proxy);
362 profile->label.proxy = proxy;
363
364 profile->label.hname = profile->base.hname;
365 profile->label.flags |= FLAG_PROFILE;
366 profile->label.vec[0] = profile;
367
368 /* refcount released by caller */
369 return profile;
370
371 fail:
372 aa_free_profile(profile);
373
374 return NULL;
375 }
376
377 /* TODO: profile accounting - setup in remove */
378
379 /**
380 * __strn_find_child - find a profile on @head list using substring of @name
381 * @head: list to search (NOT NULL)
382 * @name: name of profile (NOT NULL)
383 * @len: length of @name substring to match
384 *
385 * Requires: rcu_read_lock be held
386 *
387 * Returns: unrefcounted profile ptr, or NULL if not found
388 */
389 static struct aa_profile *__strn_find_child(struct list_head *head,
390 const char *name, int len)
391 {
392 return (struct aa_profile *)__policy_strn_find(head, name, len);
393 }
394
395 /**
396 * __find_child - find a profile on @head list with a name matching @name
397 * @head: list to search (NOT NULL)
398 * @name: name of profile (NOT NULL)
399 *
400 * Requires: rcu_read_lock be held
401 *
402 * Returns: unrefcounted profile ptr, or NULL if not found
403 */
404 static struct aa_profile *__find_child(struct list_head *head, const char *name)
405 {
406 return __strn_find_child(head, name, strlen(name));
407 }
408
409 /**
410 * aa_find_child - find a profile by @name in @parent
411 * @parent: profile to search (NOT NULL)
412 * @name: profile name to search for (NOT NULL)
413 *
414 * Returns: a refcounted profile or NULL if not found
415 */
416 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name)
417 {
418 struct aa_profile *profile;
419
420 rcu_read_lock();
421 do {
422 profile = __find_child(&parent->base.profiles, name);
423 } while (profile && !aa_get_profile_not0(profile));
424 rcu_read_unlock();
425
426 /* refcount released by caller */
427 return profile;
428 }
429
430 /**
431 * __lookup_parent - lookup the parent of a profile of name @hname
432 * @ns: namespace to lookup profile in (NOT NULL)
433 * @hname: hierarchical profile name to find parent of (NOT NULL)
434 *
435 * Lookups up the parent of a fully qualified profile name, the profile
436 * that matches hname does not need to exist, in general this
437 * is used to load a new profile.
438 *
439 * Requires: rcu_read_lock be held
440 *
441 * Returns: unrefcounted policy or NULL if not found
442 */
443 static struct aa_policy *__lookup_parent(struct aa_ns *ns,
444 const char *hname)
445 {
446 struct aa_policy *policy;
447 struct aa_profile *profile = NULL;
448 char *split;
449
450 policy = &ns->base;
451
452 for (split = strstr(hname, "//"); split;) {
453 profile = __strn_find_child(&policy->profiles, hname,
454 split - hname);
455 if (!profile)
456 return NULL;
457 policy = &profile->base;
458 hname = split + 2;
459 split = strstr(hname, "//");
460 }
461 if (!profile)
462 return &ns->base;
463 return &profile->base;
464 }
465
466 /**
467 * __create_missing_ancestors - create place holders for missing ancestores
468 * @ns: namespace to lookup profile in (NOT NULL)
469 * @hname: hierarchical profile name to find parent of (NOT NULL)
470 * @gfp: type of allocation.
471 *
472 * Requires: ns mutex lock held
473 *
474 * Return: unrefcounted parent policy on success or %NULL if error creating
475 * place holder profiles.
476 */
477 static struct aa_policy *__create_missing_ancestors(struct aa_ns *ns,
478 const char *hname,
479 gfp_t gfp)
480 {
481 struct aa_policy *policy;
482 struct aa_profile *parent, *profile = NULL;
483 char *split;
484
485 AA_BUG(!ns);
486 AA_BUG(!hname);
487
488 policy = &ns->base;
489
490 for (split = strstr(hname, "//"); split;) {
491 parent = profile;
492 profile = __strn_find_child(&policy->profiles, hname,
493 split - hname);
494 if (!profile) {
495 const char *name = kstrndup(hname, split - hname,
496 gfp);
497 if (!name)
498 return NULL;
499 profile = aa_alloc_null(parent, name, gfp);
500 kfree(name);
501 if (!profile)
502 return NULL;
503 if (!parent)
504 profile->ns = aa_get_ns(ns);
505 }
506 policy = &profile->base;
507 hname = split + 2;
508 split = strstr(hname, "//");
509 }
510 if (!profile)
511 return &ns->base;
512 return &profile->base;
513 }
514
515 /**
516 * __lookupn_profile - lookup the profile matching @hname
517 * @base: base list to start looking up profile name from (NOT NULL)
518 * @hname: hierarchical profile name (NOT NULL)
519 * @n: length of @hname
520 *
521 * Requires: rcu_read_lock be held
522 *
523 * Returns: unrefcounted profile pointer or NULL if not found
524 *
525 * Do a relative name lookup, recursing through profile tree.
526 */
527 static struct aa_profile *__lookupn_profile(struct aa_policy *base,
528 const char *hname, size_t n)
529 {
530 struct aa_profile *profile = NULL;
531 const char *split;
532
533 for (split = strnstr(hname, "//", n); split;
534 split = strnstr(hname, "//", n)) {
535 profile = __strn_find_child(&base->profiles, hname,
536 split - hname);
537 if (!profile)
538 return NULL;
539
540 base = &profile->base;
541 n -= split + 2 - hname;
542 hname = split + 2;
543 }
544
545 if (n)
546 return __strn_find_child(&base->profiles, hname, n);
547 return NULL;
548 }
549
550 static struct aa_profile *__lookup_profile(struct aa_policy *base,
551 const char *hname)
552 {
553 return __lookupn_profile(base, hname, strlen(hname));
554 }
555
556 /**
557 * aa_lookupn_profile - find a profile by its full or partial name
558 * @ns: the namespace to start from (NOT NULL)
559 * @hname: name to do lookup on. Does not contain namespace prefix (NOT NULL)
560 * @n: size of @hname
561 *
562 * Returns: refcounted profile or NULL if not found
563 */
564 struct aa_profile *aa_lookupn_profile(struct aa_ns *ns, const char *hname,
565 size_t n)
566 {
567 struct aa_profile *profile;
568
569 rcu_read_lock();
570 do {
571 profile = __lookupn_profile(&ns->base, hname, n);
572 } while (profile && !aa_get_profile_not0(profile));
573 rcu_read_unlock();
574
575 /* the unconfined profile is not in the regular profile list */
576 if (!profile && strncmp(hname, "unconfined", n) == 0)
577 profile = aa_get_newest_profile(ns->unconfined);
578
579 /* refcount released by caller */
580 return profile;
581 }
582
583 struct aa_profile *aa_lookup_profile(struct aa_ns *ns, const char *hname)
584 {
585 return aa_lookupn_profile(ns, hname, strlen(hname));
586 }
587
588 struct aa_profile *aa_fqlookupn_profile(struct aa_label *base,
589 const char *fqname, size_t n)
590 {
591 struct aa_profile *profile;
592 struct aa_ns *ns;
593 const char *name, *ns_name;
594 size_t ns_len;
595
596 name = aa_splitn_fqname(fqname, n, &ns_name, &ns_len);
597 if (ns_name) {
598 ns = aa_lookupn_ns(labels_ns(base), ns_name, ns_len);
599 if (!ns)
600 return NULL;
601 } else
602 ns = aa_get_ns(labels_ns(base));
603
604 if (name)
605 profile = aa_lookupn_profile(ns, name, n - (name - fqname));
606 else if (ns)
607 /* default profile for ns, currently unconfined */
608 profile = aa_get_newest_profile(ns->unconfined);
609 else
610 profile = NULL;
611 aa_put_ns(ns);
612
613 return profile;
614 }
615
616
617 struct aa_profile *aa_alloc_null(struct aa_profile *parent, const char *name,
618 gfp_t gfp)
619 {
620 struct aa_profile *profile;
621 struct aa_ruleset *rules;
622
623 profile = aa_alloc_profile(name, NULL, gfp);
624 if (!profile)
625 return NULL;
626
627 /* TODO: ideally we should inherit abi from parent */
628 profile->label.flags |= FLAG_NULL;
629 rules = list_first_entry(&profile->rules, typeof(*rules), list);
630 rules->file = aa_get_pdb(nullpdb);
631 rules->policy = aa_get_pdb(nullpdb);
632
633 if (parent) {
634 profile->path_flags = parent->path_flags;
635
636 /* released on free_profile */
637 rcu_assign_pointer(profile->parent, aa_get_profile(parent));
638 profile->ns = aa_get_ns(parent->ns);
639 }
640
641 return profile;
642 }
643
644 /**
645 * aa_new_learning_profile - create or find a null-X learning profile
646 * @parent: profile that caused this profile to be created (NOT NULL)
647 * @hat: true if the null- learning profile is a hat
648 * @base: name to base the null profile off of
649 * @gfp: type of allocation
650 *
651 * Find/Create a null- complain mode profile used in learning mode. The
652 * name of the profile is unique and follows the format of parent//null-XXX.
653 * where XXX is based on the @name or if that fails or is not supplied
654 * a unique number
655 *
656 * null profiles are added to the profile list but the list does not
657 * hold a count on them so that they are automatically released when
658 * not in use.
659 *
660 * Returns: new refcounted profile else NULL on failure
661 */
662 struct aa_profile *aa_new_learning_profile(struct aa_profile *parent, bool hat,
663 const char *base, gfp_t gfp)
664 {
665 struct aa_profile *p, *profile;
666 const char *bname;
667 char *name = NULL;
668
669 AA_BUG(!parent);
670
671 if (base) {
672 name = kmalloc(strlen(parent->base.hname) + 8 + strlen(base),
673 gfp);
674 if (name) {
675 sprintf(name, "%s//null-%s", parent->base.hname, base);
676 goto name;
677 }
678 /* fall through to try shorter uniq */
679 }
680
681 name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, gfp);
682 if (!name)
683 return NULL;
684 sprintf(name, "%s//null-%x", parent->base.hname,
685 atomic_inc_return(&parent->ns->uniq_null));
686
687 name:
688 /* lookup to see if this is a dup creation */
689 bname = basename(name);
690 profile = aa_find_child(parent, bname);
691 if (profile)
692 goto out;
693
694 profile = aa_alloc_null(parent, name, gfp);
695 if (!profile)
696 goto fail;
697 profile->mode = APPARMOR_COMPLAIN;
698 if (hat)
699 profile->label.flags |= FLAG_HAT;
700
701 mutex_lock_nested(&profile->ns->lock, profile->ns->level);
702 p = __find_child(&parent->base.profiles, bname);
703 if (p) {
704 aa_free_profile(profile);
705 profile = aa_get_profile(p);
706 } else {
707 __add_profile(&parent->base.profiles, profile);
708 }
709 mutex_unlock(&profile->ns->lock);
710
711 /* refcount released by caller */
712 out:
713 kfree(name);
714
715 return profile;
716
717 fail:
718 kfree(name);
719 aa_free_profile(profile);
720 return NULL;
721 }
722
723 /**
724 * replacement_allowed - test to see if replacement is allowed
725 * @profile: profile to test if it can be replaced (MAYBE NULL)
726 * @noreplace: true if replacement shouldn't be allowed but addition is okay
727 * @info: Returns - info about why replacement failed (NOT NULL)
728 *
729 * Returns: %0 if replacement allowed else error code
730 */
731 static int replacement_allowed(struct aa_profile *profile, int noreplace,
732 const char **info)
733 {
734 if (profile) {
735 if (profile->label.flags & FLAG_IMMUTIBLE) {
736 *info = "cannot replace immutable profile";
737 return -EPERM;
738 } else if (noreplace) {
739 *info = "profile already exists";
740 return -EEXIST;
741 }
742 }
743 return 0;
744 }
745
746 /* audit callback for net specific fields */
747 static void audit_cb(struct audit_buffer *ab, void *va)
748 {
749 struct common_audit_data *sa = va;
750 struct apparmor_audit_data *ad = aad(sa);
751
752 if (ad->iface.ns) {
753 audit_log_format(ab, " ns=");
754 audit_log_untrustedstring(ab, ad->iface.ns);
755 }
756 }
757
758 /**
759 * audit_policy - Do auditing of policy changes
760 * @subj_label: label to check if it can manage policy
761 * @op: policy operation being performed
762 * @ns_name: name of namespace being manipulated
763 * @name: name of profile being manipulated (NOT NULL)
764 * @info: any extra information to be audited (MAYBE NULL)
765 * @error: error code
766 *
767 * Returns: the error to be returned after audit is done
768 */
769 static int audit_policy(struct aa_label *subj_label, const char *op,
770 const char *ns_name, const char *name,
771 const char *info, int error)
772 {
773 DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_NONE, op);
774
775 ad.iface.ns = ns_name;
776 ad.name = name;
777 ad.info = info;
778 ad.error = error;
779 ad.subj_label = subj_label;
780
781 aa_audit_msg(AUDIT_APPARMOR_STATUS, &ad, audit_cb);
782
783 return error;
784 }
785
786 /* don't call out to other LSMs in the stack for apparmor policy admin
787 * permissions
788 */
789 static int policy_ns_capable(const struct cred *subj_cred,
790 struct aa_label *label,
791 struct user_namespace *userns, int cap)
792 {
793 int err;
794
795 /* check for MAC_ADMIN cap in cred */
796 err = cap_capable(subj_cred, userns, cap, CAP_OPT_NONE);
797 if (!err)
798 err = aa_capable(subj_cred, label, cap, CAP_OPT_NONE);
799
800 return err;
801 }
802
803 /**
804 * aa_policy_view_capable - check if viewing policy in at @ns is allowed
805 * @subj_cred: cred of subject
806 * @label: label that is trying to view policy in ns
807 * @ns: namespace being viewed by @label (may be NULL if @label's ns)
808 *
809 * Returns: true if viewing policy is allowed
810 *
811 * If @ns is NULL then the namespace being viewed is assumed to be the
812 * tasks current namespace.
813 */
814 bool aa_policy_view_capable(const struct cred *subj_cred,
815 struct aa_label *label, struct aa_ns *ns)
816 {
817 struct user_namespace *user_ns = subj_cred->user_ns;
818 struct aa_ns *view_ns = labels_view(label);
819 bool root_in_user_ns = uid_eq(current_euid(), make_kuid(user_ns, 0)) ||
820 in_egroup_p(make_kgid(user_ns, 0));
821 bool response = false;
822 if (!ns)
823 ns = view_ns;
824
825 if (root_in_user_ns && aa_ns_visible(view_ns, ns, true) &&
826 (user_ns == &init_user_ns ||
827 (unprivileged_userns_apparmor_policy != 0 &&
828 user_ns->level == view_ns->level)))
829 response = true;
830
831 return response;
832 }
833
834 bool aa_policy_admin_capable(const struct cred *subj_cred,
835 struct aa_label *label, struct aa_ns *ns)
836 {
837 struct user_namespace *user_ns = subj_cred->user_ns;
838 bool capable = policy_ns_capable(subj_cred, label, user_ns,
839 CAP_MAC_ADMIN) == 0;
840
841 AA_DEBUG("cap_mac_admin? %d\n", capable);
842 AA_DEBUG("policy locked? %d\n", aa_g_lock_policy);
843
844 return aa_policy_view_capable(subj_cred, label, ns) && capable &&
845 !aa_g_lock_policy;
846 }
847
848 bool aa_current_policy_view_capable(struct aa_ns *ns)
849 {
850 struct aa_label *label;
851 bool res;
852
853 label = __begin_current_label_crit_section();
854 res = aa_policy_view_capable(current_cred(), label, ns);
855 __end_current_label_crit_section(label);
856
857 return res;
858 }
859
860 bool aa_current_policy_admin_capable(struct aa_ns *ns)
861 {
862 struct aa_label *label;
863 bool res;
864
865 label = __begin_current_label_crit_section();
866 res = aa_policy_admin_capable(current_cred(), label, ns);
867 __end_current_label_crit_section(label);
868
869 return res;
870 }
871
872 /**
873 * aa_may_manage_policy - can the current task manage policy
874 * @subj_cred: subjects cred
875 * @label: label to check if it can manage policy
876 * @ns: namespace being managed by @label (may be NULL if @label's ns)
877 * @mask: contains the policy manipulation operation being done
878 *
879 * Returns: 0 if the task is allowed to manipulate policy else error
880 */
881 int aa_may_manage_policy(const struct cred *subj_cred, struct aa_label *label,
882 struct aa_ns *ns, u32 mask)
883 {
884 const char *op;
885
886 if (mask & AA_MAY_REMOVE_POLICY)
887 op = OP_PROF_RM;
888 else if (mask & AA_MAY_REPLACE_POLICY)
889 op = OP_PROF_REPL;
890 else
891 op = OP_PROF_LOAD;
892
893 /* check if loading policy is locked out */
894 if (aa_g_lock_policy)
895 return audit_policy(label, op, NULL, NULL, "policy_locked",
896 -EACCES);
897
898 if (!aa_policy_admin_capable(subj_cred, label, ns))
899 return audit_policy(label, op, NULL, NULL, "not policy admin",
900 -EACCES);
901
902 /* TODO: add fine grained mediation of policy loads */
903 return 0;
904 }
905
906 static struct aa_profile *__list_lookup_parent(struct list_head *lh,
907 struct aa_profile *profile)
908 {
909 const char *base = basename(profile->base.hname);
910 long len = base - profile->base.hname;
911 struct aa_load_ent *ent;
912
913 /* parent won't have trailing // so remove from len */
914 if (len <= 2)
915 return NULL;
916 len -= 2;
917
918 list_for_each_entry(ent, lh, list) {
919 if (ent->new == profile)
920 continue;
921 if (strncmp(ent->new->base.hname, profile->base.hname, len) ==
922 0 && ent->new->base.hname[len] == 0)
923 return ent->new;
924 }
925
926 return NULL;
927 }
928
929 /**
930 * __replace_profile - replace @old with @new on a list
931 * @old: profile to be replaced (NOT NULL)
932 * @new: profile to replace @old with (NOT NULL)
933 *
934 * Will duplicate and refcount elements that @new inherits from @old
935 * and will inherit @old children.
936 *
937 * refcount @new for list, put @old list refcount
938 *
939 * Requires: namespace list lock be held, or list not be shared
940 */
941 static void __replace_profile(struct aa_profile *old, struct aa_profile *new)
942 {
943 struct aa_profile *child, *tmp;
944
945 if (!list_empty(&old->base.profiles)) {
946 LIST_HEAD(lh);
947 list_splice_init_rcu(&old->base.profiles, &lh, synchronize_rcu);
948
949 list_for_each_entry_safe(child, tmp, &lh, base.list) {
950 struct aa_profile *p;
951
952 list_del_init(&child->base.list);
953 p = __find_child(&new->base.profiles, child->base.name);
954 if (p) {
955 /* @p replaces @child */
956 __replace_profile(child, p);
957 continue;
958 }
959
960 /* inherit @child and its children */
961 /* TODO: update hname of inherited children */
962 /* list refcount transferred to @new */
963 p = aa_deref_parent(child);
964 rcu_assign_pointer(child->parent, aa_get_profile(new));
965 list_add_rcu(&child->base.list, &new->base.profiles);
966 aa_put_profile(p);
967 }
968 }
969
970 if (!rcu_access_pointer(new->parent)) {
971 struct aa_profile *parent = aa_deref_parent(old);
972 rcu_assign_pointer(new->parent, aa_get_profile(parent));
973 }
974 aa_label_replace(&old->label, &new->label);
975 /* migrate dents must come after label replacement b/c update */
976 __aafs_profile_migrate_dents(old, new);
977
978 if (list_empty(&new->base.list)) {
979 /* new is not on a list already */
980 list_replace_rcu(&old->base.list, &new->base.list);
981 aa_get_profile(new);
982 aa_put_profile(old);
983 } else
984 __list_remove_profile(old);
985 }
986
987 /**
988 * __lookup_replace - lookup replacement information for a profile
989 * @ns: namespace the lookup occurs in
990 * @hname: name of profile to lookup
991 * @noreplace: true if not replacing an existing profile
992 * @p: Returns - profile to be replaced
993 * @info: Returns - info string on why lookup failed
994 *
995 * Returns: profile to replace (no ref) on success else ptr error
996 */
997 static int __lookup_replace(struct aa_ns *ns, const char *hname,
998 bool noreplace, struct aa_profile **p,
999 const char **info)
1000 {
1001 *p = aa_get_profile(__lookup_profile(&ns->base, hname));
1002 if (*p) {
1003 int error = replacement_allowed(*p, noreplace, info);
1004 if (error) {
1005 *info = "profile can not be replaced";
1006 return error;
1007 }
1008 }
1009
1010 return 0;
1011 }
1012
1013 static void share_name(struct aa_profile *old, struct aa_profile *new)
1014 {
1015 aa_put_str(new->base.hname);
1016 aa_get_str(old->base.hname);
1017 new->base.hname = old->base.hname;
1018 new->base.name = old->base.name;
1019 new->label.hname = old->label.hname;
1020 }
1021
1022 /* Update to newest version of parent after previous replacements
1023 * Returns: unrefcount newest version of parent
1024 */
1025 static struct aa_profile *update_to_newest_parent(struct aa_profile *new)
1026 {
1027 struct aa_profile *parent, *newest;
1028
1029 parent = rcu_dereference_protected(new->parent,
1030 mutex_is_locked(&new->ns->lock));
1031 newest = aa_get_newest_profile(parent);
1032
1033 /* parent replaced in this atomic set? */
1034 if (newest != parent) {
1035 aa_put_profile(parent);
1036 rcu_assign_pointer(new->parent, newest);
1037 } else
1038 aa_put_profile(newest);
1039
1040 return newest;
1041 }
1042
1043 /**
1044 * aa_replace_profiles - replace profile(s) on the profile list
1045 * @policy_ns: namespace load is occurring on
1046 * @label: label that is attempting to load/replace policy
1047 * @mask: permission mask
1048 * @udata: serialized data stream (NOT NULL)
1049 *
1050 * unpack and replace a profile on the profile list and uses of that profile
1051 * by any task creds via invalidating the old version of the profile, which
1052 * tasks will notice to update their own cred. If the profile does not exist
1053 * on the profile list it is added.
1054 *
1055 * Returns: size of data consumed else error code on failure.
1056 */
1057 ssize_t aa_replace_profiles(struct aa_ns *policy_ns, struct aa_label *label,
1058 u32 mask, struct aa_loaddata *udata)
1059 {
1060 const char *ns_name = NULL, *info = NULL;
1061 struct aa_ns *ns = NULL;
1062 struct aa_load_ent *ent, *tmp;
1063 struct aa_loaddata *rawdata_ent;
1064 const char *op;
1065 ssize_t count, error;
1066 LIST_HEAD(lh);
1067
1068 op = mask & AA_MAY_REPLACE_POLICY ? OP_PROF_REPL : OP_PROF_LOAD;
1069 aa_get_loaddata(udata);
1070 /* released below */
1071 error = aa_unpack(udata, &lh, &ns_name);
1072 if (error)
1073 goto out;
1074
1075 /* ensure that profiles are all for the same ns
1076 * TODO: update locking to remove this constaint. All profiles in
1077 * the load set must succeed as a set or the load will
1078 * fail. Sort ent list and take ns locks in hierarchy order
1079 */
1080 count = 0;
1081 list_for_each_entry(ent, &lh, list) {
1082 if (ns_name) {
1083 if (ent->ns_name &&
1084 strcmp(ent->ns_name, ns_name) != 0) {
1085 info = "policy load has mixed namespaces";
1086 error = -EACCES;
1087 goto fail;
1088 }
1089 } else if (ent->ns_name) {
1090 if (count) {
1091 info = "policy load has mixed namespaces";
1092 error = -EACCES;
1093 goto fail;
1094 }
1095 ns_name = ent->ns_name;
1096 } else
1097 count++;
1098 }
1099 if (ns_name) {
1100 ns = aa_prepare_ns(policy_ns ? policy_ns : labels_ns(label),
1101 ns_name);
1102 if (IS_ERR(ns)) {
1103 op = OP_PROF_LOAD;
1104 info = "failed to prepare namespace";
1105 error = PTR_ERR(ns);
1106 ns = NULL;
1107 ent = NULL;
1108 goto fail;
1109 }
1110 } else
1111 ns = aa_get_ns(policy_ns ? policy_ns : labels_ns(label));
1112
1113 mutex_lock_nested(&ns->lock, ns->level);
1114 /* check for duplicate rawdata blobs: space and file dedup */
1115 if (!list_empty(&ns->rawdata_list)) {
1116 list_for_each_entry(rawdata_ent, &ns->rawdata_list, list) {
1117 if (aa_rawdata_eq(rawdata_ent, udata)) {
1118 struct aa_loaddata *tmp;
1119
1120 tmp = __aa_get_loaddata(rawdata_ent);
1121 /* check we didn't fail the race */
1122 if (tmp) {
1123 aa_put_loaddata(udata);
1124 udata = tmp;
1125 break;
1126 }
1127 }
1128 }
1129 }
1130 /* setup parent and ns info */
1131 list_for_each_entry(ent, &lh, list) {
1132 struct aa_policy *policy;
1133 struct aa_profile *p;
1134
1135 if (aa_g_export_binary)
1136 ent->new->rawdata = aa_get_loaddata(udata);
1137 error = __lookup_replace(ns, ent->new->base.hname,
1138 !(mask & AA_MAY_REPLACE_POLICY),
1139 &ent->old, &info);
1140 if (error)
1141 goto fail_lock;
1142
1143 if (ent->new->rename) {
1144 error = __lookup_replace(ns, ent->new->rename,
1145 !(mask & AA_MAY_REPLACE_POLICY),
1146 &ent->rename, &info);
1147 if (error)
1148 goto fail_lock;
1149 }
1150
1151 /* released when @new is freed */
1152 ent->new->ns = aa_get_ns(ns);
1153
1154 if (ent->old || ent->rename)
1155 continue;
1156
1157 /* no ref on policy only use inside lock */
1158 p = NULL;
1159 policy = __lookup_parent(ns, ent->new->base.hname);
1160 if (!policy) {
1161 /* first check for parent in the load set */
1162 p = __list_lookup_parent(&lh, ent->new);
1163 if (!p) {
1164 /*
1165 * fill in missing parent with null
1166 * profile that doesn't have
1167 * permissions. This allows for
1168 * individual profile loading where
1169 * the child is loaded before the
1170 * parent, and outside of the current
1171 * atomic set. This unfortunately can
1172 * happen with some userspaces. The
1173 * null profile will be replaced once
1174 * the parent is loaded.
1175 */
1176 policy = __create_missing_ancestors(ns,
1177 ent->new->base.hname,
1178 GFP_KERNEL);
1179 if (!policy) {
1180 error = -ENOENT;
1181 info = "parent does not exist";
1182 goto fail_lock;
1183 }
1184 }
1185 }
1186 if (!p && policy != &ns->base)
1187 /* released on profile replacement or free_profile */
1188 p = (struct aa_profile *) policy;
1189 rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
1190 }
1191
1192 /* create new fs entries for introspection if needed */
1193 if (!udata->dents[AAFS_LOADDATA_DIR] && aa_g_export_binary) {
1194 error = __aa_fs_create_rawdata(ns, udata);
1195 if (error) {
1196 info = "failed to create raw_data dir and files";
1197 ent = NULL;
1198 goto fail_lock;
1199 }
1200 }
1201 list_for_each_entry(ent, &lh, list) {
1202 if (!ent->old) {
1203 struct dentry *parent;
1204 if (rcu_access_pointer(ent->new->parent)) {
1205 struct aa_profile *p;
1206 p = aa_deref_parent(ent->new);
1207 parent = prof_child_dir(p);
1208 } else
1209 parent = ns_subprofs_dir(ent->new->ns);
1210 error = __aafs_profile_mkdir(ent->new, parent);
1211 }
1212
1213 if (error) {
1214 info = "failed to create";
1215 goto fail_lock;
1216 }
1217 }
1218
1219 /* Done with checks that may fail - do actual replacement */
1220 __aa_bump_ns_revision(ns);
1221 if (aa_g_export_binary)
1222 __aa_loaddata_update(udata, ns->revision);
1223 list_for_each_entry_safe(ent, tmp, &lh, list) {
1224 list_del_init(&ent->list);
1225 op = (!ent->old && !ent->rename) ? OP_PROF_LOAD : OP_PROF_REPL;
1226
1227 if (ent->old && ent->old->rawdata == ent->new->rawdata &&
1228 ent->new->rawdata) {
1229 /* dedup actual profile replacement */
1230 audit_policy(label, op, ns_name, ent->new->base.hname,
1231 "same as current profile, skipping",
1232 error);
1233 /* break refcount cycle with proxy. */
1234 aa_put_proxy(ent->new->label.proxy);
1235 ent->new->label.proxy = NULL;
1236 goto skip;
1237 }
1238
1239 /*
1240 * TODO: finer dedup based on profile range in data. Load set
1241 * can differ but profile may remain unchanged
1242 */
1243 audit_policy(label, op, ns_name, ent->new->base.hname, NULL,
1244 error);
1245
1246 if (ent->old) {
1247 share_name(ent->old, ent->new);
1248 __replace_profile(ent->old, ent->new);
1249 } else {
1250 struct list_head *lh;
1251
1252 if (rcu_access_pointer(ent->new->parent)) {
1253 struct aa_profile *parent;
1254
1255 parent = update_to_newest_parent(ent->new);
1256 lh = &parent->base.profiles;
1257 } else
1258 lh = &ns->base.profiles;
1259 __add_profile(lh, ent->new);
1260 }
1261 skip:
1262 aa_load_ent_free(ent);
1263 }
1264 __aa_labelset_update_subtree(ns);
1265 mutex_unlock(&ns->lock);
1266
1267 out:
1268 aa_put_ns(ns);
1269 aa_put_loaddata(udata);
1270 kfree(ns_name);
1271
1272 if (error)
1273 return error;
1274 return udata->size;
1275
1276 fail_lock:
1277 mutex_unlock(&ns->lock);
1278
1279 /* audit cause of failure */
1280 op = (ent && !ent->old) ? OP_PROF_LOAD : OP_PROF_REPL;
1281 fail:
1282 audit_policy(label, op, ns_name, ent ? ent->new->base.hname : NULL,
1283 info, error);
1284 /* audit status that rest of profiles in the atomic set failed too */
1285 info = "valid profile in failed atomic policy load";
1286 list_for_each_entry(tmp, &lh, list) {
1287 if (tmp == ent) {
1288 info = "unchecked profile in failed atomic policy load";
1289 /* skip entry that caused failure */
1290 continue;
1291 }
1292 op = (!tmp->old) ? OP_PROF_LOAD : OP_PROF_REPL;
1293 audit_policy(label, op, ns_name, tmp->new->base.hname, info,
1294 error);
1295 }
1296 list_for_each_entry_safe(ent, tmp, &lh, list) {
1297 list_del_init(&ent->list);
1298 aa_load_ent_free(ent);
1299 }
1300
1301 goto out;
1302 }
1303
1304 /**
1305 * aa_remove_profiles - remove profile(s) from the system
1306 * @policy_ns: namespace the remove is being done from
1307 * @subj: label attempting to remove policy
1308 * @fqname: name of the profile or namespace to remove (NOT NULL)
1309 * @size: size of the name
1310 *
1311 * Remove a profile or sub namespace from the current namespace, so that
1312 * they can not be found anymore and mark them as replaced by unconfined
1313 *
1314 * NOTE: removing confinement does not restore rlimits to preconfinement values
1315 *
1316 * Returns: size of data consume else error code if fails
1317 */
1318 ssize_t aa_remove_profiles(struct aa_ns *policy_ns, struct aa_label *subj,
1319 char *fqname, size_t size)
1320 {
1321 struct aa_ns *ns = NULL;
1322 struct aa_profile *profile = NULL;
1323 const char *name = fqname, *info = NULL;
1324 const char *ns_name = NULL;
1325 ssize_t error = 0;
1326
1327 if (*fqname == 0) {
1328 info = "no profile specified";
1329 error = -ENOENT;
1330 goto fail;
1331 }
1332
1333 if (fqname[0] == ':') {
1334 size_t ns_len;
1335
1336 name = aa_splitn_fqname(fqname, size, &ns_name, &ns_len);
1337 /* released below */
1338 ns = aa_lookupn_ns(policy_ns ? policy_ns : labels_ns(subj),
1339 ns_name, ns_len);
1340 if (!ns) {
1341 info = "namespace does not exist";
1342 error = -ENOENT;
1343 goto fail;
1344 }
1345 } else
1346 /* released below */
1347 ns = aa_get_ns(policy_ns ? policy_ns : labels_ns(subj));
1348
1349 if (!name) {
1350 /* remove namespace - can only happen if fqname[0] == ':' */
1351 mutex_lock_nested(&ns->parent->lock, ns->parent->level);
1352 __aa_bump_ns_revision(ns);
1353 __aa_remove_ns(ns);
1354 mutex_unlock(&ns->parent->lock);
1355 } else {
1356 /* remove profile */
1357 mutex_lock_nested(&ns->lock, ns->level);
1358 profile = aa_get_profile(__lookup_profile(&ns->base, name));
1359 if (!profile) {
1360 error = -ENOENT;
1361 info = "profile does not exist";
1362 goto fail_ns_lock;
1363 }
1364 name = profile->base.hname;
1365 __aa_bump_ns_revision(ns);
1366 __remove_profile(profile);
1367 __aa_labelset_update_subtree(ns);
1368 mutex_unlock(&ns->lock);
1369 }
1370
1371 /* don't fail removal if audit fails */
1372 (void) audit_policy(subj, OP_PROF_RM, ns_name, name, info,
1373 error);
1374 aa_put_ns(ns);
1375 aa_put_profile(profile);
1376 return size;
1377
1378 fail_ns_lock:
1379 mutex_unlock(&ns->lock);
1380 aa_put_ns(ns);
1381
1382 fail:
1383 (void) audit_policy(subj, OP_PROF_RM, ns_name, name, info,
1384 error);
1385 return error;
1386 }
1387
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