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

source code of linux/security/apparmor/policy.c