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 *pdb)
103{
104 if (pdb) {
105 aa_put_dfa(dfa: pdb->dfa);
106 kvfree(addr: pdb->perms);
107 aa_free_str_table(table: &pdb->trans);
108 kfree(objp: pdb);
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(pdb);
121}
122
123
124struct aa_policydb *aa_alloc_pdb(gfp_t gfp)
125{
126 struct aa_policydb *pdb = kzalloc(sizeof(struct aa_policydb), 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 kvfree_sensitive(addr: data->data, len: data->size);
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 if (!rules)
247 return;
248
249 aa_put_pdb(pdb: rules->file);
250 aa_put_pdb(pdb: rules->policy);
251 aa_free_cap_rules(caps: &rules->caps);
252 aa_free_rlimit_rules(rlims: &rules->rlimits);
253
254 for (i = 0; i < rules->secmark_count; i++)
255 kfree_sensitive(objp: rules->secmark[i].label);
256 kfree_sensitive(objp: rules->secmark);
257 kfree_sensitive(objp: rules);
258}
259
260struct aa_ruleset *aa_alloc_ruleset(gfp_t gfp)
261{
262 struct aa_ruleset *rules;
263
264 rules = kzalloc(sizeof(*rules), gfp);
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 */
279void aa_free_profile(struct aa_profile *profile)
280{
281 struct rhashtable *rht;
282
283 AA_DEBUG(DEBUG_POLICY, "%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 for (int i = 0; i < profile->n_rules; i++)
303 free_ruleset(rules: profile->label.rules[i]);
304
305 kfree_sensitive(objp: profile->dirname);
306
307 if (profile->data) {
308 rht = profile->data;
309 profile->data = NULL;
310 rhashtable_free_and_destroy(ht: rht, free_fn: aa_free_data, NULL);
311 kfree_sensitive(objp: rht);
312 }
313
314 kfree_sensitive(objp: profile->hash);
315 aa_put_loaddata(data: profile->rawdata);
316 aa_label_destroy(label: &profile->label);
317
318 kfree_sensitive(objp: profile);
319}
320
321/**
322 * aa_alloc_profile - allocate, initialize and return a new profile
323 * @hname: name of the profile (NOT NULL)
324 * @proxy: proxy to use OR null if to allocate a new one
325 * @gfp: allocation type
326 *
327 * Returns: refcount profile or NULL on failure
328 */
329struct aa_profile *aa_alloc_profile(const char *hname, struct aa_proxy *proxy,
330 gfp_t gfp)
331{
332 struct aa_profile *profile;
333
334 /* freed by free_profile - usually through aa_put_profile
335 * this adds space for a single ruleset in the rules section of the
336 * label
337 */
338 profile = kzalloc(struct_size(profile, label.rules, 1), gfp);
339 if (!profile)
340 return NULL;
341
342 if (!aa_policy_init(policy: &profile->base, NULL, name: hname, gfp))
343 goto fail;
344 if (!aa_label_init(label: &profile->label, size: 1, gfp))
345 goto fail;
346
347 /* allocate the first ruleset, but leave it empty */
348 profile->label.rules[0] = aa_alloc_ruleset(gfp);
349 if (!profile->label.rules[0])
350 goto fail;
351 profile->n_rules = 1;
352
353 /* update being set needed by fs interface */
354 if (!proxy) {
355 proxy = aa_alloc_proxy(l: &profile->label, gfp);
356 if (!proxy)
357 goto fail;
358 } else
359 aa_get_proxy(proxy);
360 profile->label.proxy = proxy;
361
362 profile->label.hname = profile->base.hname;
363 profile->label.flags |= FLAG_PROFILE;
364 profile->label.vec[0] = profile;
365
366 profile->signal = SIGKILL;
367 /* refcount released by caller */
368 return profile;
369
370fail:
371 aa_free_profile(profile);
372
373 return NULL;
374}
375
376static inline bool ANY_RULE_MEDIATES(struct aa_profile *profile,
377 unsigned char class)
378{
379 int i;
380
381 for (i = 0; i < profile->n_rules; i++) {
382 if (RULE_MEDIATES(rules: profile->label.rules[i], class))
383 return true;
384 }
385 return false;
386}
387
388/* set of rules that are mediated by unconfined */
389static int unconfined_mediates[] = { AA_CLASS_NS, AA_CLASS_IO_URING, 0 };
390
391/* must be called after profile rulesets and start information is setup */
392void aa_compute_profile_mediates(struct aa_profile *profile)
393{
394 int c;
395
396 if (profile_unconfined(profile)) {
397 int *pos;
398
399 for (pos = unconfined_mediates; *pos; pos++) {
400 if (ANY_RULE_MEDIATES(profile, class: *pos))
401 profile->label.mediates |= ((u64) 1) << AA_CLASS_NS;
402 }
403 return;
404 }
405 for (c = 0; c <= AA_CLASS_LAST; c++) {
406 if (ANY_RULE_MEDIATES(profile, class: c))
407 profile->label.mediates |= ((u64) 1) << c;
408 }
409}
410
411/* TODO: profile accounting - setup in remove */
412
413/**
414 * __strn_find_child - find a profile on @head list using substring of @name
415 * @head: list to search (NOT NULL)
416 * @name: name of profile (NOT NULL)
417 * @len: length of @name substring to match
418 *
419 * Requires: rcu_read_lock be held
420 *
421 * Returns: unrefcounted profile ptr, or NULL if not found
422 */
423static struct aa_profile *__strn_find_child(struct list_head *head,
424 const char *name, int len)
425{
426 return (struct aa_profile *)__policy_strn_find(head, str: name, len);
427}
428
429/**
430 * __find_child - find a profile on @head list with a name matching @name
431 * @head: list to search (NOT NULL)
432 * @name: name of profile (NOT NULL)
433 *
434 * Requires: rcu_read_lock be held
435 *
436 * Returns: unrefcounted profile ptr, or NULL if not found
437 */
438static struct aa_profile *__find_child(struct list_head *head, const char *name)
439{
440 return __strn_find_child(head, name, strlen(name));
441}
442
443/**
444 * aa_find_child - find a profile by @name in @parent
445 * @parent: profile to search (NOT NULL)
446 * @name: profile name to search for (NOT NULL)
447 *
448 * Returns: a refcounted profile or NULL if not found
449 */
450struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name)
451{
452 struct aa_profile *profile;
453
454 rcu_read_lock();
455 do {
456 profile = __find_child(head: &parent->base.profiles, name);
457 } while (profile && !aa_get_profile_not0(p: profile));
458 rcu_read_unlock();
459
460 /* refcount released by caller */
461 return profile;
462}
463
464/**
465 * __lookup_parent - lookup the parent of a profile of name @hname
466 * @ns: namespace to lookup profile in (NOT NULL)
467 * @hname: hierarchical profile name to find parent of (NOT NULL)
468 *
469 * Lookups up the parent of a fully qualified profile name, the profile
470 * that matches hname does not need to exist, in general this
471 * is used to load a new profile.
472 *
473 * Requires: rcu_read_lock be held
474 *
475 * Returns: unrefcounted policy or NULL if not found
476 */
477static struct aa_policy *__lookup_parent(struct aa_ns *ns,
478 const char *hname)
479{
480 struct aa_policy *policy;
481 struct aa_profile *profile = NULL;
482 char *split;
483
484 policy = &ns->base;
485
486 for (split = strstr(hname, "//"); split;) {
487 profile = __strn_find_child(head: &policy->profiles, name: hname,
488 len: split - hname);
489 if (!profile)
490 return NULL;
491 policy = &profile->base;
492 hname = split + 2;
493 split = strstr(hname, "//");
494 }
495 if (!profile)
496 return &ns->base;
497 return &profile->base;
498}
499
500/**
501 * __create_missing_ancestors - create place holders for missing ancestors
502 * @ns: namespace to lookup profile in (NOT NULL)
503 * @hname: hierarchical profile name to find parent of (NOT NULL)
504 * @gfp: type of allocation.
505 *
506 * Requires: ns mutex lock held
507 *
508 * Return: unrefcounted parent policy on success or %NULL if error creating
509 * place holder profiles.
510 */
511static struct aa_policy *__create_missing_ancestors(struct aa_ns *ns,
512 const char *hname,
513 gfp_t gfp)
514{
515 struct aa_policy *policy;
516 struct aa_profile *parent, *profile = NULL;
517 char *split;
518
519 AA_BUG(!ns);
520 AA_BUG(!hname);
521
522 policy = &ns->base;
523
524 for (split = strstr(hname, "//"); split;) {
525 parent = profile;
526 profile = __strn_find_child(head: &policy->profiles, name: hname,
527 len: split - hname);
528 if (!profile) {
529 const char *name = kstrndup(s: hname, len: split - hname,
530 gfp);
531 if (!name)
532 return NULL;
533 profile = aa_alloc_null(parent, name, gfp);
534 kfree(objp: name);
535 if (!profile)
536 return NULL;
537 if (!parent)
538 profile->ns = aa_get_ns(ns);
539 }
540 policy = &profile->base;
541 hname = split + 2;
542 split = strstr(hname, "//");
543 }
544 if (!profile)
545 return &ns->base;
546 return &profile->base;
547}
548
549/**
550 * __lookupn_profile - lookup the profile matching @hname
551 * @base: base list to start looking up profile name from (NOT NULL)
552 * @hname: hierarchical profile name (NOT NULL)
553 * @n: length of @hname
554 *
555 * Requires: rcu_read_lock be held
556 *
557 * Returns: unrefcounted profile pointer or NULL if not found
558 *
559 * Do a relative name lookup, recursing through profile tree.
560 */
561static struct aa_profile *__lookupn_profile(struct aa_policy *base,
562 const char *hname, size_t n)
563{
564 struct aa_profile *profile = NULL;
565 const char *split;
566
567 for (split = strnstr(hname, "//", n); split;
568 split = strnstr(hname, "//", n)) {
569 profile = __strn_find_child(head: &base->profiles, name: hname,
570 len: split - hname);
571 if (!profile)
572 return NULL;
573
574 base = &profile->base;
575 n -= split + 2 - hname;
576 hname = split + 2;
577 }
578
579 if (n)
580 return __strn_find_child(head: &base->profiles, name: hname, len: n);
581 return NULL;
582}
583
584static struct aa_profile *__lookup_profile(struct aa_policy *base,
585 const char *hname)
586{
587 return __lookupn_profile(base, hname, strlen(hname));
588}
589
590/**
591 * aa_lookupn_profile - find a profile by its full or partial name
592 * @ns: the namespace to start from (NOT NULL)
593 * @hname: name to do lookup on. Does not contain namespace prefix (NOT NULL)
594 * @n: size of @hname
595 *
596 * Returns: refcounted profile or NULL if not found
597 */
598struct aa_profile *aa_lookupn_profile(struct aa_ns *ns, const char *hname,
599 size_t n)
600{
601 struct aa_profile *profile;
602
603 rcu_read_lock();
604 do {
605 profile = __lookupn_profile(base: &ns->base, hname, n);
606 } while (profile && !aa_get_profile_not0(p: profile));
607 rcu_read_unlock();
608
609 /* the unconfined profile is not in the regular profile list */
610 if (!profile && strncmp(hname, "unconfined", n) == 0)
611 profile = aa_get_newest_profile(p: ns->unconfined);
612
613 /* refcount released by caller */
614 return profile;
615}
616
617struct aa_profile *aa_fqlookupn_profile(struct aa_label *base,
618 const char *fqname, size_t n)
619{
620 struct aa_profile *profile;
621 struct aa_ns *ns;
622 const char *name, *ns_name;
623 size_t ns_len;
624
625 name = aa_splitn_fqname(fqname, n, ns_name: &ns_name, ns_len: &ns_len);
626 if (ns_name) {
627 ns = aa_lookupn_ns(labels_ns(base), name: ns_name, n: ns_len);
628 if (!ns)
629 return NULL;
630 } else
631 ns = aa_get_ns(labels_ns(base));
632
633 if (name)
634 profile = aa_lookupn_profile(ns, hname: name, n: n - (name - fqname));
635 else if (ns)
636 /* default profile for ns, currently unconfined */
637 profile = aa_get_newest_profile(p: ns->unconfined);
638 else
639 profile = NULL;
640 aa_put_ns(ns);
641
642 return profile;
643}
644
645
646struct aa_profile *aa_alloc_null(struct aa_profile *parent, const char *name,
647 gfp_t gfp)
648{
649 struct aa_profile *profile;
650 struct aa_ruleset *rules;
651
652 profile = aa_alloc_profile(hname: name, NULL, gfp);
653 if (!profile)
654 return NULL;
655
656 /* TODO: ideally we should inherit abi from parent */
657 profile->label.flags |= FLAG_NULL;
658 profile->attach.xmatch = aa_get_pdb(pdb: nullpdb);
659 rules = profile->label.rules[0];
660 rules->file = aa_get_pdb(pdb: nullpdb);
661 rules->policy = aa_get_pdb(pdb: nullpdb);
662 aa_compute_profile_mediates(profile);
663
664 if (parent) {
665 profile->path_flags = parent->path_flags;
666 /* override/inherit what is mediated from parent */
667 profile->label.mediates = parent->label.mediates;
668 /* released on free_profile */
669 rcu_assign_pointer(profile->parent, aa_get_profile(parent));
670 profile->ns = aa_get_ns(ns: parent->ns);
671 }
672
673 return profile;
674}
675
676/**
677 * aa_new_learning_profile - create or find a null-X learning profile
678 * @parent: profile that caused this profile to be created (NOT NULL)
679 * @hat: true if the null- learning profile is a hat
680 * @base: name to base the null profile off of
681 * @gfp: type of allocation
682 *
683 * Find/Create a null- complain mode profile used in learning mode. The
684 * name of the profile is unique and follows the format of parent//null-XXX.
685 * where XXX is based on the @name or if that fails or is not supplied
686 * a unique number
687 *
688 * null profiles are added to the profile list but the list does not
689 * hold a count on them so that they are automatically released when
690 * not in use.
691 *
692 * Returns: new refcounted profile else NULL on failure
693 */
694struct aa_profile *aa_new_learning_profile(struct aa_profile *parent, bool hat,
695 const char *base, gfp_t gfp)
696{
697 struct aa_profile *p, *profile;
698 const char *bname;
699 char *name = NULL;
700
701 AA_BUG(!parent);
702
703 if (base) {
704 name = kmalloc(strlen(parent->base.hname) + 8 + strlen(base),
705 gfp);
706 if (name) {
707 sprintf(buf: name, fmt: "%s//null-%s", parent->base.hname, base);
708 goto name;
709 }
710 /* fall through to try shorter uniq */
711 }
712
713 name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, gfp);
714 if (!name)
715 return NULL;
716 sprintf(buf: name, fmt: "%s//null-%x", parent->base.hname,
717 atomic_inc_return(v: &parent->ns->uniq_null));
718
719name:
720 /* lookup to see if this is a dup creation */
721 bname = basename(hname: name);
722 profile = aa_find_child(parent, name: bname);
723 if (profile)
724 goto out;
725
726 profile = aa_alloc_null(parent, name, gfp);
727 if (!profile)
728 goto fail;
729 profile->mode = APPARMOR_COMPLAIN;
730 if (hat)
731 profile->label.flags |= FLAG_HAT;
732
733 mutex_lock_nested(lock: &profile->ns->lock, subclass: profile->ns->level);
734 p = __find_child(head: &parent->base.profiles, name: bname);
735 if (p) {
736 aa_free_profile(profile);
737 profile = aa_get_profile(p);
738 } else {
739 __add_profile(list: &parent->base.profiles, profile);
740 }
741 mutex_unlock(lock: &profile->ns->lock);
742
743 /* refcount released by caller */
744out:
745 kfree(objp: name);
746
747 return profile;
748
749fail:
750 kfree(objp: name);
751 aa_free_profile(profile);
752 return NULL;
753}
754
755/**
756 * replacement_allowed - test to see if replacement is allowed
757 * @profile: profile to test if it can be replaced (MAYBE NULL)
758 * @noreplace: true if replacement shouldn't be allowed but addition is okay
759 * @info: Returns - info about why replacement failed (NOT NULL)
760 *
761 * Returns: %0 if replacement allowed else error code
762 */
763static int replacement_allowed(struct aa_profile *profile, int noreplace,
764 const char **info)
765{
766 if (profile) {
767 if (profile->label.flags & FLAG_IMMUTIBLE) {
768 *info = "cannot replace immutable profile";
769 return -EPERM;
770 } else if (noreplace) {
771 *info = "profile already exists";
772 return -EEXIST;
773 }
774 }
775 return 0;
776}
777
778/* audit callback for net specific fields */
779static void audit_cb(struct audit_buffer *ab, void *va)
780{
781 struct common_audit_data *sa = va;
782 struct apparmor_audit_data *ad = aad(sa);
783
784 if (ad->iface.ns) {
785 audit_log_format(ab, fmt: " ns=");
786 audit_log_untrustedstring(ab, string: ad->iface.ns);
787 }
788}
789
790/**
791 * audit_policy - Do auditing of policy changes
792 * @subj_label: label to check if it can manage policy
793 * @op: policy operation being performed
794 * @ns_name: name of namespace being manipulated
795 * @name: name of profile being manipulated (NOT NULL)
796 * @info: any extra information to be audited (MAYBE NULL)
797 * @error: error code
798 *
799 * Returns: the error to be returned after audit is done
800 */
801static int audit_policy(struct aa_label *subj_label, const char *op,
802 const char *ns_name, const char *name,
803 const char *info, int error)
804{
805 DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_NONE, op);
806
807 ad.iface.ns = ns_name;
808 ad.name = name;
809 ad.info = info;
810 ad.error = error;
811 ad.subj_label = subj_label;
812
813 aa_audit_msg(type: AUDIT_APPARMOR_STATUS, ad: &ad, cb: audit_cb);
814
815 return error;
816}
817
818/* don't call out to other LSMs in the stack for apparmor policy admin
819 * permissions
820 */
821static int policy_ns_capable(const struct cred *subj_cred,
822 struct aa_label *label,
823 struct user_namespace *userns, int cap)
824{
825 int err;
826
827 /* check for MAC_ADMIN cap in cred */
828 err = cap_capable(cred: subj_cred, ns: userns, cap, CAP_OPT_NONE);
829 if (!err)
830 err = aa_capable(subj_cred, label, cap, CAP_OPT_NONE);
831
832 return err;
833}
834
835/**
836 * aa_policy_view_capable - check if viewing policy in at @ns is allowed
837 * @subj_cred: cred of subject
838 * @label: label that is trying to view policy in ns
839 * @ns: namespace being viewed by @label (may be NULL if @label's ns)
840 *
841 * Returns: true if viewing policy is allowed
842 *
843 * If @ns is NULL then the namespace being viewed is assumed to be the
844 * tasks current namespace.
845 */
846bool aa_policy_view_capable(const struct cred *subj_cred,
847 struct aa_label *label, struct aa_ns *ns)
848{
849 struct user_namespace *user_ns = subj_cred->user_ns;
850 struct aa_ns *view_ns = labels_view(label);
851 bool root_in_user_ns = uid_eq(current_euid(), right: make_kuid(from: user_ns, uid: 0)) ||
852 in_egroup_p(make_kgid(from: user_ns, gid: 0));
853 bool response = false;
854 if (!ns)
855 ns = view_ns;
856
857 if (root_in_user_ns && aa_ns_visible(curr: view_ns, view: ns, subns: true) &&
858 (user_ns == &init_user_ns ||
859 (unprivileged_userns_apparmor_policy != 0 &&
860 user_ns->level == view_ns->level)))
861 response = true;
862
863 return response;
864}
865
866bool aa_policy_admin_capable(const struct cred *subj_cred,
867 struct aa_label *label, struct aa_ns *ns)
868{
869 struct user_namespace *user_ns = subj_cred->user_ns;
870 bool capable = policy_ns_capable(subj_cred, label, userns: user_ns,
871 CAP_MAC_ADMIN) == 0;
872
873 AA_DEBUG(DEBUG_POLICY, "cap_mac_admin? %d\n", capable);
874 AA_DEBUG(DEBUG_POLICY, "policy locked? %d\n", aa_g_lock_policy);
875
876 return aa_policy_view_capable(subj_cred, label, ns) && capable &&
877 !aa_g_lock_policy;
878}
879
880bool aa_current_policy_view_capable(struct aa_ns *ns)
881{
882 struct aa_label *label;
883 bool needput, res;
884
885 label = __begin_current_label_crit_section(needput: &needput);
886 res = aa_policy_view_capable(current_cred(), label, ns);
887 __end_current_label_crit_section(label, needput);
888
889 return res;
890}
891
892bool aa_current_policy_admin_capable(struct aa_ns *ns)
893{
894 struct aa_label *label;
895 bool needput, res;
896
897 label = __begin_current_label_crit_section(needput: &needput);
898 res = aa_policy_admin_capable(current_cred(), label, ns);
899 __end_current_label_crit_section(label, needput);
900
901 return res;
902}
903
904/**
905 * aa_may_manage_policy - can the current task manage policy
906 * @subj_cred: subjects cred
907 * @label: label to check if it can manage policy
908 * @ns: namespace being managed by @label (may be NULL if @label's ns)
909 * @mask: contains the policy manipulation operation being done
910 *
911 * Returns: 0 if the task is allowed to manipulate policy else error
912 */
913int aa_may_manage_policy(const struct cred *subj_cred, struct aa_label *label,
914 struct aa_ns *ns, u32 mask)
915{
916 const char *op;
917
918 if (mask & AA_MAY_REMOVE_POLICY)
919 op = OP_PROF_RM;
920 else if (mask & AA_MAY_REPLACE_POLICY)
921 op = OP_PROF_REPL;
922 else
923 op = OP_PROF_LOAD;
924
925 /* check if loading policy is locked out */
926 if (aa_g_lock_policy)
927 return audit_policy(subj_label: label, op, NULL, NULL, info: "policy_locked",
928 error: -EACCES);
929
930 if (!aa_policy_admin_capable(subj_cred, label, ns))
931 return audit_policy(subj_label: label, op, NULL, NULL, info: "not policy admin",
932 error: -EACCES);
933
934 /* TODO: add fine grained mediation of policy loads */
935 return 0;
936}
937
938static struct aa_profile *__list_lookup_parent(struct list_head *lh,
939 struct aa_profile *profile)
940{
941 const char *base = basename(hname: profile->base.hname);
942 long len = base - profile->base.hname;
943 struct aa_load_ent *ent;
944
945 /* parent won't have trailing // so remove from len */
946 if (len <= 2)
947 return NULL;
948 len -= 2;
949
950 list_for_each_entry(ent, lh, list) {
951 if (ent->new == profile)
952 continue;
953 if (strncmp(ent->new->base.hname, profile->base.hname, len) ==
954 0 && ent->new->base.hname[len] == 0)
955 return ent->new;
956 }
957
958 return NULL;
959}
960
961/**
962 * __replace_profile - replace @old with @new on a list
963 * @old: profile to be replaced (NOT NULL)
964 * @new: profile to replace @old with (NOT NULL)
965 *
966 * Will duplicate and refcount elements that @new inherits from @old
967 * and will inherit @old children.
968 *
969 * refcount @new for list, put @old list refcount
970 *
971 * Requires: namespace list lock be held, or list not be shared
972 */
973static void __replace_profile(struct aa_profile *old, struct aa_profile *new)
974{
975 struct aa_profile *child, *tmp;
976
977 if (!list_empty(head: &old->base.profiles)) {
978 LIST_HEAD(lh);
979 list_splice_init_rcu(list: &old->base.profiles, head: &lh, sync: synchronize_rcu);
980
981 list_for_each_entry_safe(child, tmp, &lh, base.list) {
982 struct aa_profile *p;
983
984 list_del_init(entry: &child->base.list);
985 p = __find_child(head: &new->base.profiles, name: child->base.name);
986 if (p) {
987 /* @p replaces @child */
988 __replace_profile(old: child, new: p);
989 continue;
990 }
991
992 /* inherit @child and its children */
993 /* TODO: update hname of inherited children */
994 /* list refcount transferred to @new */
995 p = aa_deref_parent(p: child);
996 rcu_assign_pointer(child->parent, aa_get_profile(new));
997 list_add_rcu(new: &child->base.list, head: &new->base.profiles);
998 aa_put_profile(p);
999 }
1000 }
1001
1002 if (!rcu_access_pointer(new->parent)) {
1003 struct aa_profile *parent = aa_deref_parent(p: old);
1004 rcu_assign_pointer(new->parent, aa_get_profile(parent));
1005 }
1006 aa_label_replace(old: &old->label, new: &new->label);
1007 /* migrate dents must come after label replacement b/c update */
1008 __aafs_profile_migrate_dents(old, new);
1009
1010 if (list_empty(head: &new->base.list)) {
1011 /* new is not on a list already */
1012 list_replace_rcu(old: &old->base.list, new: &new->base.list);
1013 aa_get_profile(p: new);
1014 aa_put_profile(p: old);
1015 } else
1016 __list_remove_profile(profile: old);
1017}
1018
1019/**
1020 * __lookup_replace - lookup replacement information for a profile
1021 * @ns: namespace the lookup occurs in
1022 * @hname: name of profile to lookup
1023 * @noreplace: true if not replacing an existing profile
1024 * @p: Returns - profile to be replaced
1025 * @info: Returns - info string on why lookup failed
1026 *
1027 * Returns: profile to replace (no ref) on success else ptr error
1028 */
1029static int __lookup_replace(struct aa_ns *ns, const char *hname,
1030 bool noreplace, struct aa_profile **p,
1031 const char **info)
1032{
1033 *p = aa_get_profile(p: __lookup_profile(base: &ns->base, hname));
1034 if (*p) {
1035 int error = replacement_allowed(profile: *p, noreplace, info);
1036 if (error) {
1037 *info = "profile can not be replaced";
1038 return error;
1039 }
1040 }
1041
1042 return 0;
1043}
1044
1045static void share_name(struct aa_profile *old, struct aa_profile *new)
1046{
1047 aa_put_str(str: new->base.hname);
1048 aa_get_str(str: old->base.hname);
1049 new->base.hname = old->base.hname;
1050 new->base.name = old->base.name;
1051 new->label.hname = old->label.hname;
1052}
1053
1054/* Update to newest version of parent after previous replacements
1055 * Returns: unrefcount newest version of parent
1056 */
1057static struct aa_profile *update_to_newest_parent(struct aa_profile *new)
1058{
1059 struct aa_profile *parent, *newest;
1060
1061 parent = rcu_dereference_protected(new->parent,
1062 mutex_is_locked(&new->ns->lock));
1063 newest = aa_get_newest_profile(p: parent);
1064
1065 /* parent replaced in this atomic set? */
1066 if (newest != parent) {
1067 aa_put_profile(p: parent);
1068 rcu_assign_pointer(new->parent, newest);
1069 } else
1070 aa_put_profile(p: newest);
1071
1072 return newest;
1073}
1074
1075/**
1076 * aa_replace_profiles - replace profile(s) on the profile list
1077 * @policy_ns: namespace load is occurring on
1078 * @label: label that is attempting to load/replace policy
1079 * @mask: permission mask
1080 * @udata: serialized data stream (NOT NULL)
1081 *
1082 * unpack and replace a profile on the profile list and uses of that profile
1083 * by any task creds via invalidating the old version of the profile, which
1084 * tasks will notice to update their own cred. If the profile does not exist
1085 * on the profile list it is added.
1086 *
1087 * Returns: size of data consumed else error code on failure.
1088 */
1089ssize_t aa_replace_profiles(struct aa_ns *policy_ns, struct aa_label *label,
1090 u32 mask, struct aa_loaddata *udata)
1091{
1092 const char *ns_name = NULL, *info = NULL;
1093 struct aa_ns *ns = NULL;
1094 struct aa_load_ent *ent, *tmp;
1095 struct aa_loaddata *rawdata_ent;
1096 const char *op;
1097 ssize_t count, error;
1098 LIST_HEAD(lh);
1099
1100 op = mask & AA_MAY_REPLACE_POLICY ? OP_PROF_REPL : OP_PROF_LOAD;
1101 aa_get_loaddata(data: udata);
1102 /* released below */
1103 error = aa_unpack(udata, lh: &lh, ns: &ns_name);
1104 if (error)
1105 goto out;
1106
1107 /* ensure that profiles are all for the same ns
1108 * TODO: update locking to remove this constraint. All profiles in
1109 * the load set must succeed as a set or the load will
1110 * fail. Sort ent list and take ns locks in hierarchy order
1111 */
1112 count = 0;
1113 list_for_each_entry(ent, &lh, list) {
1114 if (ns_name) {
1115 if (ent->ns_name &&
1116 strcmp(ent->ns_name, ns_name) != 0) {
1117 info = "policy load has mixed namespaces";
1118 error = -EACCES;
1119 goto fail;
1120 }
1121 } else if (ent->ns_name) {
1122 if (count) {
1123 info = "policy load has mixed namespaces";
1124 error = -EACCES;
1125 goto fail;
1126 }
1127 ns_name = ent->ns_name;
1128 } else
1129 count++;
1130 }
1131 if (ns_name) {
1132 ns = aa_prepare_ns(root: policy_ns ? policy_ns : labels_ns(label),
1133 name: ns_name);
1134 if (IS_ERR(ptr: ns)) {
1135 op = OP_PROF_LOAD;
1136 info = "failed to prepare namespace";
1137 error = PTR_ERR(ptr: ns);
1138 ns = NULL;
1139 ent = NULL;
1140 goto fail;
1141 }
1142 } else
1143 ns = aa_get_ns(ns: policy_ns ? policy_ns : labels_ns(label));
1144
1145 mutex_lock_nested(lock: &ns->lock, subclass: ns->level);
1146 /* check for duplicate rawdata blobs: space and file dedup */
1147 if (!list_empty(head: &ns->rawdata_list)) {
1148 list_for_each_entry(rawdata_ent, &ns->rawdata_list, list) {
1149 if (aa_rawdata_eq(l: rawdata_ent, r: udata)) {
1150 struct aa_loaddata *tmp;
1151
1152 tmp = __aa_get_loaddata(data: rawdata_ent);
1153 /* check we didn't fail the race */
1154 if (tmp) {
1155 aa_put_loaddata(data: udata);
1156 udata = tmp;
1157 break;
1158 }
1159 }
1160 }
1161 }
1162 /* setup parent and ns info */
1163 list_for_each_entry(ent, &lh, list) {
1164 struct aa_policy *policy;
1165 struct aa_profile *p;
1166
1167 if (aa_g_export_binary)
1168 ent->new->rawdata = aa_get_loaddata(data: udata);
1169 error = __lookup_replace(ns, hname: ent->new->base.hname,
1170 noreplace: !(mask & AA_MAY_REPLACE_POLICY),
1171 p: &ent->old, info: &info);
1172 if (error)
1173 goto fail_lock;
1174
1175 if (ent->new->rename) {
1176 error = __lookup_replace(ns, hname: ent->new->rename,
1177 noreplace: !(mask & AA_MAY_REPLACE_POLICY),
1178 p: &ent->rename, info: &info);
1179 if (error)
1180 goto fail_lock;
1181 }
1182
1183 /* released when @new is freed */
1184 ent->new->ns = aa_get_ns(ns);
1185
1186 if (ent->old || ent->rename)
1187 continue;
1188
1189 /* no ref on policy only use inside lock */
1190 p = NULL;
1191 policy = __lookup_parent(ns, hname: ent->new->base.hname);
1192 if (!policy) {
1193 /* first check for parent in the load set */
1194 p = __list_lookup_parent(lh: &lh, profile: ent->new);
1195 if (!p) {
1196 /*
1197 * fill in missing parent with null
1198 * profile that doesn't have
1199 * permissions. This allows for
1200 * individual profile loading where
1201 * the child is loaded before the
1202 * parent, and outside of the current
1203 * atomic set. This unfortunately can
1204 * happen with some userspaces. The
1205 * null profile will be replaced once
1206 * the parent is loaded.
1207 */
1208 policy = __create_missing_ancestors(ns,
1209 hname: ent->new->base.hname,
1210 GFP_KERNEL);
1211 if (!policy) {
1212 error = -ENOENT;
1213 info = "parent does not exist";
1214 goto fail_lock;
1215 }
1216 }
1217 }
1218 if (!p && policy != &ns->base)
1219 /* released on profile replacement or free_profile */
1220 p = (struct aa_profile *) policy;
1221 rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
1222 }
1223
1224 /* create new fs entries for introspection if needed */
1225 if (!udata->dents[AAFS_LOADDATA_DIR] && aa_g_export_binary) {
1226 error = __aa_fs_create_rawdata(ns, rawdata: udata);
1227 if (error) {
1228 info = "failed to create raw_data dir and files";
1229 ent = NULL;
1230 goto fail_lock;
1231 }
1232 }
1233 list_for_each_entry(ent, &lh, list) {
1234 if (!ent->old) {
1235 struct dentry *parent;
1236 if (rcu_access_pointer(ent->new->parent)) {
1237 struct aa_profile *p;
1238 p = aa_deref_parent(p: ent->new);
1239 parent = prof_child_dir(p);
1240 } else
1241 parent = ns_subprofs_dir(ent->new->ns);
1242 error = __aafs_profile_mkdir(profile: ent->new, parent);
1243 }
1244
1245 if (error) {
1246 info = "failed to create";
1247 goto fail_lock;
1248 }
1249 }
1250
1251 /* Done with checks that may fail - do actual replacement */
1252 __aa_bump_ns_revision(ns);
1253 if (aa_g_export_binary)
1254 __aa_loaddata_update(data: udata, revision: ns->revision);
1255 list_for_each_entry_safe(ent, tmp, &lh, list) {
1256 list_del_init(entry: &ent->list);
1257 op = (!ent->old && !ent->rename) ? OP_PROF_LOAD : OP_PROF_REPL;
1258
1259 if (ent->old && ent->old->rawdata == ent->new->rawdata &&
1260 ent->new->rawdata) {
1261 /* dedup actual profile replacement */
1262 audit_policy(subj_label: label, op, ns_name, name: ent->new->base.hname,
1263 info: "same as current profile, skipping",
1264 error);
1265 /* break refcount cycle with proxy. */
1266 aa_put_proxy(proxy: ent->new->label.proxy);
1267 ent->new->label.proxy = NULL;
1268 goto skip;
1269 }
1270
1271 /*
1272 * TODO: finer dedup based on profile range in data. Load set
1273 * can differ but profile may remain unchanged
1274 */
1275 audit_policy(subj_label: label, op, ns_name, name: ent->new->base.hname, NULL,
1276 error);
1277
1278 if (ent->old) {
1279 share_name(old: ent->old, new: ent->new);
1280 __replace_profile(old: ent->old, new: ent->new);
1281 } else {
1282 struct list_head *lh;
1283
1284 if (rcu_access_pointer(ent->new->parent)) {
1285 struct aa_profile *parent;
1286
1287 parent = update_to_newest_parent(new: ent->new);
1288 lh = &parent->base.profiles;
1289 } else
1290 lh = &ns->base.profiles;
1291 __add_profile(list: lh, profile: ent->new);
1292 }
1293 skip:
1294 aa_load_ent_free(ent);
1295 }
1296 __aa_labelset_update_subtree(ns);
1297 mutex_unlock(lock: &ns->lock);
1298
1299out:
1300 aa_put_ns(ns);
1301 aa_put_loaddata(data: udata);
1302 kfree(objp: ns_name);
1303
1304 if (error)
1305 return error;
1306 return udata->size;
1307
1308fail_lock:
1309 mutex_unlock(lock: &ns->lock);
1310
1311 /* audit cause of failure */
1312 op = (ent && !ent->old) ? OP_PROF_LOAD : OP_PROF_REPL;
1313fail:
1314 audit_policy(subj_label: label, op, ns_name, name: ent ? ent->new->base.hname : NULL,
1315 info, error);
1316 /* audit status that rest of profiles in the atomic set failed too */
1317 info = "valid profile in failed atomic policy load";
1318 list_for_each_entry(tmp, &lh, list) {
1319 if (tmp == ent) {
1320 info = "unchecked profile in failed atomic policy load";
1321 /* skip entry that caused failure */
1322 continue;
1323 }
1324 op = (!tmp->old) ? OP_PROF_LOAD : OP_PROF_REPL;
1325 audit_policy(subj_label: label, op, ns_name, name: tmp->new->base.hname, info,
1326 error);
1327 }
1328 list_for_each_entry_safe(ent, tmp, &lh, list) {
1329 list_del_init(entry: &ent->list);
1330 aa_load_ent_free(ent);
1331 }
1332
1333 goto out;
1334}
1335
1336/**
1337 * aa_remove_profiles - remove profile(s) from the system
1338 * @policy_ns: namespace the remove is being done from
1339 * @subj: label attempting to remove policy
1340 * @fqname: name of the profile or namespace to remove (NOT NULL)
1341 * @size: size of the name
1342 *
1343 * Remove a profile or sub namespace from the current namespace, so that
1344 * they can not be found anymore and mark them as replaced by unconfined
1345 *
1346 * NOTE: removing confinement does not restore rlimits to preconfinement values
1347 *
1348 * Returns: size of data consume else error code if fails
1349 */
1350ssize_t aa_remove_profiles(struct aa_ns *policy_ns, struct aa_label *subj,
1351 char *fqname, size_t size)
1352{
1353 struct aa_ns *ns = NULL;
1354 struct aa_profile *profile = NULL;
1355 const char *name = fqname, *info = NULL;
1356 const char *ns_name = NULL;
1357 ssize_t error = 0;
1358
1359 if (*fqname == 0) {
1360 info = "no profile specified";
1361 error = -ENOENT;
1362 goto fail;
1363 }
1364
1365 if (fqname[0] == ':') {
1366 size_t ns_len;
1367
1368 name = aa_splitn_fqname(fqname, n: size, ns_name: &ns_name, ns_len: &ns_len);
1369 /* released below */
1370 ns = aa_lookupn_ns(view: policy_ns ? policy_ns : labels_ns(subj),
1371 name: ns_name, n: ns_len);
1372 if (!ns) {
1373 info = "namespace does not exist";
1374 error = -ENOENT;
1375 goto fail;
1376 }
1377 } else
1378 /* released below */
1379 ns = aa_get_ns(ns: policy_ns ? policy_ns : labels_ns(subj));
1380
1381 if (!name) {
1382 /* remove namespace - can only happen if fqname[0] == ':' */
1383 mutex_lock_nested(lock: &ns->parent->lock, subclass: ns->parent->level);
1384 __aa_bump_ns_revision(ns);
1385 __aa_remove_ns(ns);
1386 mutex_unlock(lock: &ns->parent->lock);
1387 } else {
1388 /* remove profile */
1389 mutex_lock_nested(lock: &ns->lock, subclass: ns->level);
1390 profile = aa_get_profile(p: __lookup_profile(base: &ns->base, hname: name));
1391 if (!profile) {
1392 error = -ENOENT;
1393 info = "profile does not exist";
1394 goto fail_ns_lock;
1395 }
1396 name = profile->base.hname;
1397 __aa_bump_ns_revision(ns);
1398 __remove_profile(profile);
1399 __aa_labelset_update_subtree(ns);
1400 mutex_unlock(lock: &ns->lock);
1401 }
1402
1403 /* don't fail removal if audit fails */
1404 (void) audit_policy(subj_label: subj, OP_PROF_RM, ns_name, name, info,
1405 error);
1406 aa_put_ns(ns);
1407 aa_put_profile(p: profile);
1408 return size;
1409
1410fail_ns_lock:
1411 mutex_unlock(lock: &ns->lock);
1412 aa_put_ns(ns);
1413
1414fail:
1415 (void) audit_policy(subj_label: subj, OP_PROF_RM, ns_name, name, info,
1416 error);
1417 return error;
1418}
1419

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