xref: /linux/security/apparmor/policy.c (revision c97204baf840bf850e14ef4f5f43251239ca43b6)
1 /*
2  * AppArmor security module
3  *
4  * This file contains AppArmor policy manipulation functions
5  *
6  * Copyright (C) 1998-2008 Novell/SUSE
7  * Copyright 2009-2010 Canonical Ltd.
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License as
11  * published by the Free Software Foundation, version 2 of the
12  * License.
13  *
14  *
15  * AppArmor policy is based around profiles, which contain the rules a
16  * task is confined by.  Every task in the system has a profile attached
17  * to it determined either by matching "unconfined" tasks against the
18  * visible set of profiles or by following a profiles attachment rules.
19  *
20  * Each profile exists in a profile namespace which is a container of
21  * visible profiles.  Each namespace contains a special "unconfined" profile,
22  * which doesn't enforce any confinement on a task beyond DAC.
23  *
24  * Namespace and profile names can be written together in either
25  * of two syntaxes.
26  *	:namespace:profile - used by kernel interfaces for easy detection
27  *	namespace://profile - used by policy
28  *
29  * Profile names can not start with : or @ or ^ and may not contain \0
30  *
31  * Reserved profile names
32  *	unconfined - special automatically generated unconfined profile
33  *	inherit - special name to indicate profile inheritance
34  *	null-XXXX-YYYY - special automatically generated learning profiles
35  *
36  * Namespace names may not start with / or @ and may not contain \0 or :
37  * Reserved namespace names
38  *	user-XXXX - user defined profiles
39  *
40  * a // in a profile or namespace name indicates a hierarchical name with the
41  * name before the // being the parent and the name after the child.
42  *
43  * Profile and namespace hierarchies serve two different but similar purposes.
44  * The namespace contains the set of visible profiles that are considered
45  * for attachment.  The hierarchy of namespaces allows for virtualizing
46  * the namespace so that for example a chroot can have its own set of profiles
47  * which may define some local user namespaces.
48  * The profile hierarchy severs two distinct purposes,
49  * -  it allows for sub profiles or hats, which allows an application to run
50  *    subprograms under its own profile with different restriction than it
51  *    self, and not have it use the system profile.
52  *    eg. if a mail program starts an editor, the policy might make the
53  *        restrictions tighter on the editor tighter than the mail program,
54  *        and definitely different than general editor restrictions
55  * - it allows for binary hierarchy of profiles, so that execution history
56  *   is preserved.  This feature isn't exploited by AppArmor reference policy
57  *   but is allowed.  NOTE: this is currently suboptimal because profile
58  *   aliasing is not currently implemented so that a profile for each
59  *   level must be defined.
60  *   eg. /bin/bash///bin/ls as a name would indicate /bin/ls was started
61  *       from /bin/bash
62  *
63  *   A profile or namespace name that can contain one or more // separators
64  *   is referred to as an hname (hierarchical).
65  *   eg.  /bin/bash//bin/ls
66  *
67  *   An fqname is a name that may contain both namespace and profile hnames.
68  *   eg. :ns:/bin/bash//bin/ls
69  *
70  * NOTES:
71  *   - locking of profile lists is currently fairly coarse.  All profile
72  *     lists within a namespace use the namespace lock.
73  * FIXME: move profile lists to using rcu_lists
74  */
75 
76 #include <linux/slab.h>
77 #include <linux/spinlock.h>
78 #include <linux/string.h>
79 #include <linux/cred.h>
80 #include <linux/rculist.h>
81 #include <linux/user_namespace.h>
82 
83 #include "include/apparmor.h"
84 #include "include/capability.h"
85 #include "include/context.h"
86 #include "include/file.h"
87 #include "include/ipc.h"
88 #include "include/match.h"
89 #include "include/path.h"
90 #include "include/policy.h"
91 #include "include/policy_ns.h"
92 #include "include/policy_unpack.h"
93 #include "include/resource.h"
94 
95 int unprivileged_userns_apparmor_policy = 1;
96 
97 const char *const aa_profile_mode_names[] = {
98 	"enforce",
99 	"complain",
100 	"kill",
101 	"unconfined",
102 };
103 
104 /* requires profile list write lock held */
105 void __aa_update_proxy(struct aa_profile *orig, struct aa_profile *new)
106 {
107 	struct aa_profile *tmp;
108 
109 	tmp = rcu_dereference_protected(orig->proxy->profile,
110 					mutex_is_locked(&orig->ns->lock));
111 	rcu_assign_pointer(orig->proxy->profile, aa_get_profile(new));
112 	orig->flags |= PFLAG_STALE;
113 	aa_put_profile(tmp);
114 }
115 
116 /**
117  * __list_add_profile - add a profile to a list
118  * @list: list to add it to  (NOT NULL)
119  * @profile: the profile to add  (NOT NULL)
120  *
121  * refcount @profile, should be put by __list_remove_profile
122  *
123  * Requires: namespace lock be held, or list not be shared
124  */
125 static void __list_add_profile(struct list_head *list,
126 			       struct aa_profile *profile)
127 {
128 	list_add_rcu(&profile->base.list, list);
129 	/* get list reference */
130 	aa_get_profile(profile);
131 }
132 
133 /**
134  * __list_remove_profile - remove a profile from the list it is on
135  * @profile: the profile to remove  (NOT NULL)
136  *
137  * remove a profile from the list, warning generally removal should
138  * be done with __replace_profile as most profile removals are
139  * replacements to the unconfined profile.
140  *
141  * put @profile list refcount
142  *
143  * Requires: namespace lock be held, or list not have been live
144  */
145 static void __list_remove_profile(struct aa_profile *profile)
146 {
147 	list_del_rcu(&profile->base.list);
148 	aa_put_profile(profile);
149 }
150 
151 /**
152  * __remove_profile - remove old profile, and children
153  * @profile: profile to be replaced  (NOT NULL)
154  *
155  * Requires: namespace list lock be held, or list not be shared
156  */
157 static void __remove_profile(struct aa_profile *profile)
158 {
159 	/* release any children lists first */
160 	__aa_profile_list_release(&profile->base.profiles);
161 	/* released by free_profile */
162 	__aa_update_proxy(profile, profile->ns->unconfined);
163 	__aafs_profile_rmdir(profile);
164 	__list_remove_profile(profile);
165 }
166 
167 /**
168  * __aa_profile_list_release - remove all profiles on the list and put refs
169  * @head: list of profiles  (NOT NULL)
170  *
171  * Requires: namespace lock be held
172  */
173 void __aa_profile_list_release(struct list_head *head)
174 {
175 	struct aa_profile *profile, *tmp;
176 	list_for_each_entry_safe(profile, tmp, head, base.list)
177 		__remove_profile(profile);
178 }
179 
180 
181 static void free_proxy(struct aa_proxy *p)
182 {
183 	if (p) {
184 		/* r->profile will not be updated any more as r is dead */
185 		aa_put_profile(rcu_dereference_protected(p->profile, true));
186 		kzfree(p);
187 	}
188 }
189 
190 
191 void aa_free_proxy_kref(struct kref *kref)
192 {
193 	struct aa_proxy *p = container_of(kref, struct aa_proxy, count);
194 
195 	free_proxy(p);
196 }
197 
198 /**
199  * aa_free_data - free a data blob
200  * @ptr: data to free
201  * @arg: unused
202  */
203 static void aa_free_data(void *ptr, void *arg)
204 {
205 	struct aa_data *data = ptr;
206 
207 	kzfree(data->data);
208 	kzfree(data->key);
209 	kzfree(data);
210 }
211 
212 /**
213  * aa_free_profile - free a profile
214  * @profile: the profile to free  (MAYBE NULL)
215  *
216  * Free a profile, its hats and null_profile. All references to the profile,
217  * its hats and null_profile must have been put.
218  *
219  * If the profile was referenced from a task context, free_profile() will
220  * be called from an rcu callback routine, so we must not sleep here.
221  */
222 void aa_free_profile(struct aa_profile *profile)
223 {
224 	struct rhashtable *rht;
225 
226 	AA_DEBUG("%s(%p)\n", __func__, profile);
227 
228 	if (!profile)
229 		return;
230 
231 	/* free children profiles */
232 	aa_policy_destroy(&profile->base);
233 	aa_put_profile(rcu_access_pointer(profile->parent));
234 
235 	aa_put_ns(profile->ns);
236 	kzfree(profile->rename);
237 
238 	aa_free_file_rules(&profile->file);
239 	aa_free_cap_rules(&profile->caps);
240 	aa_free_rlimit_rules(&profile->rlimits);
241 
242 	kzfree(profile->dirname);
243 	aa_put_dfa(profile->xmatch);
244 	aa_put_dfa(profile->policy.dfa);
245 	aa_put_proxy(profile->proxy);
246 
247 	if (profile->data) {
248 		rht = profile->data;
249 		profile->data = NULL;
250 		rhashtable_free_and_destroy(rht, aa_free_data, NULL);
251 		kzfree(rht);
252 	}
253 
254 	kzfree(profile->hash);
255 	aa_put_loaddata(profile->rawdata);
256 	kzfree(profile);
257 }
258 
259 /**
260  * aa_free_profile_rcu - free aa_profile by rcu (called by aa_free_profile_kref)
261  * @head: rcu_head callback for freeing of a profile  (NOT NULL)
262  */
263 static void aa_free_profile_rcu(struct rcu_head *head)
264 {
265 	struct aa_profile *p = container_of(head, struct aa_profile, rcu);
266 	if (p->flags & PFLAG_NS_COUNT)
267 		aa_free_ns(p->ns);
268 	else
269 		aa_free_profile(p);
270 }
271 
272 /**
273  * aa_free_profile_kref - free aa_profile by kref (called by aa_put_profile)
274  * @kr: kref callback for freeing of a profile  (NOT NULL)
275  */
276 void aa_free_profile_kref(struct kref *kref)
277 {
278 	struct aa_profile *p = container_of(kref, struct aa_profile, count);
279 	call_rcu(&p->rcu, aa_free_profile_rcu);
280 }
281 
282 /**
283  * aa_alloc_profile - allocate, initialize and return a new profile
284  * @hname: name of the profile  (NOT NULL)
285  * @gfp: allocation type
286  *
287  * Returns: refcount profile or NULL on failure
288  */
289 struct aa_profile *aa_alloc_profile(const char *hname, gfp_t gfp)
290 {
291 	struct aa_profile *profile;
292 
293 	/* freed by free_profile - usually through aa_put_profile */
294 	profile = kzalloc(sizeof(*profile), gfp);
295 	if (!profile)
296 		return NULL;
297 
298 	profile->proxy = kzalloc(sizeof(struct aa_proxy), gfp);
299 	if (!profile->proxy)
300 		goto fail;
301 	kref_init(&profile->proxy->count);
302 
303 	if (!aa_policy_init(&profile->base, NULL, hname, gfp))
304 		goto fail;
305 	kref_init(&profile->count);
306 
307 	/* refcount released by caller */
308 	return profile;
309 
310 fail:
311 	kzfree(profile->proxy);
312 	kzfree(profile);
313 
314 	return NULL;
315 }
316 
317 /**
318  * aa_new_null_profile - create or find a null-X learning profile
319  * @parent: profile that caused this profile to be created (NOT NULL)
320  * @hat: true if the null- learning profile is a hat
321  * @base: name to base the null profile off of
322  * @gfp: type of allocation
323  *
324  * Find/Create a null- complain mode profile used in learning mode.  The
325  * name of the profile is unique and follows the format of parent//null-XXX.
326  * where XXX is based on the @name or if that fails or is not supplied
327  * a unique number
328  *
329  * null profiles are added to the profile list but the list does not
330  * hold a count on them so that they are automatically released when
331  * not in use.
332  *
333  * Returns: new refcounted profile else NULL on failure
334  */
335 struct aa_profile *aa_new_null_profile(struct aa_profile *parent, bool hat,
336 				       const char *base, gfp_t gfp)
337 {
338 	struct aa_profile *profile;
339 	char *name;
340 
341 	AA_BUG(!parent);
342 
343 	if (base) {
344 		name = kmalloc(strlen(parent->base.hname) + 8 + strlen(base),
345 			       gfp);
346 		if (name) {
347 			sprintf(name, "%s//null-%s", parent->base.hname, base);
348 			goto name;
349 		}
350 		/* fall through to try shorter uniq */
351 	}
352 
353 	name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, gfp);
354 	if (!name)
355 		return NULL;
356 	sprintf(name, "%s//null-%x", parent->base.hname,
357 		atomic_inc_return(&parent->ns->uniq_null));
358 
359 name:
360 	/* lookup to see if this is a dup creation */
361 	profile = aa_find_child(parent, basename(name));
362 	if (profile)
363 		goto out;
364 
365 	profile = aa_alloc_profile(name, gfp);
366 	if (!profile)
367 		goto fail;
368 
369 	profile->mode = APPARMOR_COMPLAIN;
370 	profile->flags |= PFLAG_NULL;
371 	if (hat)
372 		profile->flags |= PFLAG_HAT;
373 	profile->path_flags = parent->path_flags;
374 
375 	/* released on free_profile */
376 	rcu_assign_pointer(profile->parent, aa_get_profile(parent));
377 	profile->ns = aa_get_ns(parent->ns);
378 	profile->file.dfa = aa_get_dfa(nulldfa);
379 	profile->policy.dfa = aa_get_dfa(nulldfa);
380 
381 	mutex_lock(&profile->ns->lock);
382 	__list_add_profile(&parent->base.profiles, profile);
383 	mutex_unlock(&profile->ns->lock);
384 
385 	/* refcount released by caller */
386 out:
387 	kfree(name);
388 
389 	return profile;
390 
391 fail:
392 	kfree(name);
393 	aa_free_profile(profile);
394 	return NULL;
395 }
396 
397 /* TODO: profile accounting - setup in remove */
398 
399 /**
400  * __find_child - find a profile on @head list with a name matching @name
401  * @head: list to search  (NOT NULL)
402  * @name: name of profile (NOT NULL)
403  *
404  * Requires: rcu_read_lock be held
405  *
406  * Returns: unrefcounted profile ptr, or NULL if not found
407  */
408 static struct aa_profile *__find_child(struct list_head *head, const char *name)
409 {
410 	return (struct aa_profile *)__policy_find(head, name);
411 }
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  */
423 static 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, name, len);
427 }
428 
429 /**
430  * aa_find_child - find a profile by @name in @parent
431  * @parent: profile to search  (NOT NULL)
432  * @name: profile name to search for  (NOT NULL)
433  *
434  * Returns: a refcounted profile or NULL if not found
435  */
436 struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name)
437 {
438 	struct aa_profile *profile;
439 
440 	rcu_read_lock();
441 	do {
442 		profile = __find_child(&parent->base.profiles, name);
443 	} while (profile && !aa_get_profile_not0(profile));
444 	rcu_read_unlock();
445 
446 	/* refcount released by caller */
447 	return profile;
448 }
449 
450 /**
451  * __lookup_parent - lookup the parent of a profile of name @hname
452  * @ns: namespace to lookup profile in  (NOT NULL)
453  * @hname: hierarchical profile name to find parent of  (NOT NULL)
454  *
455  * Lookups up the parent of a fully qualified profile name, the profile
456  * that matches hname does not need to exist, in general this
457  * is used to load a new profile.
458  *
459  * Requires: rcu_read_lock be held
460  *
461  * Returns: unrefcounted policy or NULL if not found
462  */
463 static struct aa_policy *__lookup_parent(struct aa_ns *ns,
464 					 const char *hname)
465 {
466 	struct aa_policy *policy;
467 	struct aa_profile *profile = NULL;
468 	char *split;
469 
470 	policy = &ns->base;
471 
472 	for (split = strstr(hname, "//"); split;) {
473 		profile = __strn_find_child(&policy->profiles, hname,
474 					    split - hname);
475 		if (!profile)
476 			return NULL;
477 		policy = &profile->base;
478 		hname = split + 2;
479 		split = strstr(hname, "//");
480 	}
481 	if (!profile)
482 		return &ns->base;
483 	return &profile->base;
484 }
485 
486 /**
487  * __lookupn_profile - lookup the profile matching @hname
488  * @base: base list to start looking up profile name from  (NOT NULL)
489  * @hname: hierarchical profile name  (NOT NULL)
490  * @n: length of @hname
491  *
492  * Requires: rcu_read_lock be held
493  *
494  * Returns: unrefcounted profile pointer or NULL if not found
495  *
496  * Do a relative name lookup, recursing through profile tree.
497  */
498 static struct aa_profile *__lookupn_profile(struct aa_policy *base,
499 					    const char *hname, size_t n)
500 {
501 	struct aa_profile *profile = NULL;
502 	const char *split;
503 
504 	for (split = strnstr(hname, "//", n); split;
505 	     split = strnstr(hname, "//", n)) {
506 		profile = __strn_find_child(&base->profiles, hname,
507 					    split - hname);
508 		if (!profile)
509 			return NULL;
510 
511 		base = &profile->base;
512 		n -= split + 2 - hname;
513 		hname = split + 2;
514 	}
515 
516 	if (n)
517 		return __strn_find_child(&base->profiles, hname, n);
518 	return NULL;
519 }
520 
521 static struct aa_profile *__lookup_profile(struct aa_policy *base,
522 					   const char *hname)
523 {
524 	return __lookupn_profile(base, hname, strlen(hname));
525 }
526 
527 /**
528  * aa_lookup_profile - find a profile by its full or partial name
529  * @ns: the namespace to start from (NOT NULL)
530  * @hname: name to do lookup on.  Does not contain namespace prefix (NOT NULL)
531  * @n: size of @hname
532  *
533  * Returns: refcounted profile or NULL if not found
534  */
535 struct aa_profile *aa_lookupn_profile(struct aa_ns *ns, const char *hname,
536 				      size_t n)
537 {
538 	struct aa_profile *profile;
539 
540 	rcu_read_lock();
541 	do {
542 		profile = __lookupn_profile(&ns->base, hname, n);
543 	} while (profile && !aa_get_profile_not0(profile));
544 	rcu_read_unlock();
545 
546 	/* the unconfined profile is not in the regular profile list */
547 	if (!profile && strncmp(hname, "unconfined", n) == 0)
548 		profile = aa_get_newest_profile(ns->unconfined);
549 
550 	/* refcount released by caller */
551 	return profile;
552 }
553 
554 struct aa_profile *aa_lookup_profile(struct aa_ns *ns, const char *hname)
555 {
556 	return aa_lookupn_profile(ns, hname, strlen(hname));
557 }
558 
559 struct aa_profile *aa_fqlookupn_profile(struct aa_profile *base,
560 					const char *fqname, size_t n)
561 {
562 	struct aa_profile *profile;
563 	struct aa_ns *ns;
564 	const char *name, *ns_name;
565 	size_t ns_len;
566 
567 	name = aa_splitn_fqname(fqname, n, &ns_name, &ns_len);
568 	if (ns_name) {
569 		ns = aa_findn_ns(base->ns, ns_name, ns_len);
570 		if (!ns)
571 			return NULL;
572 	} else
573 		ns = aa_get_ns(base->ns);
574 
575 	if (name)
576 		profile = aa_lookupn_profile(ns, name, n - (name - fqname));
577 	else if (ns)
578 		/* default profile for ns, currently unconfined */
579 		profile = aa_get_newest_profile(ns->unconfined);
580 	else
581 		profile = NULL;
582 	aa_put_ns(ns);
583 
584 	return profile;
585 }
586 
587 /**
588  * replacement_allowed - test to see if replacement is allowed
589  * @profile: profile to test if it can be replaced  (MAYBE NULL)
590  * @noreplace: true if replacement shouldn't be allowed but addition is okay
591  * @info: Returns - info about why replacement failed (NOT NULL)
592  *
593  * Returns: %0 if replacement allowed else error code
594  */
595 static int replacement_allowed(struct aa_profile *profile, int noreplace,
596 			       const char **info)
597 {
598 	if (profile) {
599 		if (profile->flags & PFLAG_IMMUTABLE) {
600 			*info = "cannot replace immutible profile";
601 			return -EPERM;
602 		} else if (noreplace) {
603 			*info = "profile already exists";
604 			return -EEXIST;
605 		}
606 	}
607 	return 0;
608 }
609 
610 /* audit callback for net specific fields */
611 static void audit_cb(struct audit_buffer *ab, void *va)
612 {
613 	struct common_audit_data *sa = va;
614 
615 	if (aad(sa)->iface.ns) {
616 		audit_log_format(ab, " ns=");
617 		audit_log_untrustedstring(ab, aad(sa)->iface.ns);
618 	}
619 }
620 
621 /**
622  * aa_audit_policy - Do auditing of policy changes
623  * @profile: profile to check if it can manage policy
624  * @op: policy operation being performed
625  * @gfp: memory allocation flags
626  * @nsname: name of the ns being manipulated (MAY BE NULL)
627  * @name: name of profile being manipulated (NOT NULL)
628  * @info: any extra information to be audited (MAYBE NULL)
629  * @error: error code
630  *
631  * Returns: the error to be returned after audit is done
632  */
633 static int audit_policy(struct aa_profile *profile, const char *op,
634 			const char *nsname, const char *name,
635 			const char *info, int error)
636 {
637 	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, op);
638 
639 	aad(&sa)->iface.ns = nsname;
640 	aad(&sa)->name = name;
641 	aad(&sa)->info = info;
642 	aad(&sa)->error = error;
643 
644 	return aa_audit(AUDIT_APPARMOR_STATUS, profile, &sa, audit_cb);
645 }
646 
647 /**
648  * policy_view_capable - check if viewing policy in at @ns is allowed
649  * ns: namespace being viewed by current task (may be NULL)
650  * Returns: true if viewing policy is allowed
651  *
652  * If @ns is NULL then the namespace being viewed is assumed to be the
653  * tasks current namespace.
654  */
655 bool policy_view_capable(struct aa_ns *ns)
656 {
657 	struct user_namespace *user_ns = current_user_ns();
658 	struct aa_ns *view_ns = aa_get_current_ns();
659 	bool root_in_user_ns = uid_eq(current_euid(), make_kuid(user_ns, 0)) ||
660 			       in_egroup_p(make_kgid(user_ns, 0));
661 	bool response = false;
662 	if (!ns)
663 		ns = view_ns;
664 
665 	if (root_in_user_ns && aa_ns_visible(view_ns, ns, true) &&
666 	    (user_ns == &init_user_ns ||
667 	     (unprivileged_userns_apparmor_policy != 0 &&
668 	      user_ns->level == view_ns->level)))
669 		response = true;
670 	aa_put_ns(view_ns);
671 
672 	return response;
673 }
674 
675 bool policy_admin_capable(struct aa_ns *ns)
676 {
677 	struct user_namespace *user_ns = current_user_ns();
678 	bool capable = ns_capable(user_ns, CAP_MAC_ADMIN);
679 
680 	AA_DEBUG("cap_mac_admin? %d\n", capable);
681 	AA_DEBUG("policy locked? %d\n", aa_g_lock_policy);
682 
683 	return policy_view_capable(ns) && capable && !aa_g_lock_policy;
684 }
685 
686 /**
687  * aa_may_manage_policy - can the current task manage policy
688  * @profile: profile to check if it can manage policy
689  * @op: the policy manipulation operation being done
690  *
691  * Returns: 0 if the task is allowed to manipulate policy else error
692  */
693 int aa_may_manage_policy(struct aa_profile *profile, struct aa_ns *ns,
694 			 const char *op)
695 {
696 	/* check if loading policy is locked out */
697 	if (aa_g_lock_policy)
698 		return audit_policy(profile, op, NULL, NULL,
699 			     "policy_locked", -EACCES);
700 
701 	if (!policy_admin_capable(ns))
702 		return audit_policy(profile, op, NULL, NULL,
703 				    "not policy admin", -EACCES);
704 
705 	/* TODO: add fine grained mediation of policy loads */
706 	return 0;
707 }
708 
709 static struct aa_profile *__list_lookup_parent(struct list_head *lh,
710 					       struct aa_profile *profile)
711 {
712 	const char *base = basename(profile->base.hname);
713 	long len = base - profile->base.hname;
714 	struct aa_load_ent *ent;
715 
716 	/* parent won't have trailing // so remove from len */
717 	if (len <= 2)
718 		return NULL;
719 	len -= 2;
720 
721 	list_for_each_entry(ent, lh, list) {
722 		if (ent->new == profile)
723 			continue;
724 		if (strncmp(ent->new->base.hname, profile->base.hname, len) ==
725 		    0 && ent->new->base.hname[len] == 0)
726 			return ent->new;
727 	}
728 
729 	return NULL;
730 }
731 
732 /**
733  * __replace_profile - replace @old with @new on a list
734  * @old: profile to be replaced  (NOT NULL)
735  * @new: profile to replace @old with  (NOT NULL)
736  * @share_proxy: transfer @old->proxy to @new
737  *
738  * Will duplicate and refcount elements that @new inherits from @old
739  * and will inherit @old children.
740  *
741  * refcount @new for list, put @old list refcount
742  *
743  * Requires: namespace list lock be held, or list not be shared
744  */
745 static void __replace_profile(struct aa_profile *old, struct aa_profile *new,
746 			      bool share_proxy)
747 {
748 	struct aa_profile *child, *tmp;
749 
750 	if (!list_empty(&old->base.profiles)) {
751 		LIST_HEAD(lh);
752 		list_splice_init_rcu(&old->base.profiles, &lh, synchronize_rcu);
753 
754 		list_for_each_entry_safe(child, tmp, &lh, base.list) {
755 			struct aa_profile *p;
756 
757 			list_del_init(&child->base.list);
758 			p = __find_child(&new->base.profiles, child->base.name);
759 			if (p) {
760 				/* @p replaces @child  */
761 				__replace_profile(child, p, share_proxy);
762 				continue;
763 			}
764 
765 			/* inherit @child and its children */
766 			/* TODO: update hname of inherited children */
767 			/* list refcount transferred to @new */
768 			p = aa_deref_parent(child);
769 			rcu_assign_pointer(child->parent, aa_get_profile(new));
770 			list_add_rcu(&child->base.list, &new->base.profiles);
771 			aa_put_profile(p);
772 		}
773 	}
774 
775 	if (!rcu_access_pointer(new->parent)) {
776 		struct aa_profile *parent = aa_deref_parent(old);
777 		rcu_assign_pointer(new->parent, aa_get_profile(parent));
778 	}
779 	__aa_update_proxy(old, new);
780 	if (share_proxy) {
781 		aa_put_proxy(new->proxy);
782 		new->proxy = aa_get_proxy(old->proxy);
783 	} else if (!rcu_access_pointer(new->proxy->profile))
784 		/* aafs interface uses proxy */
785 		rcu_assign_pointer(new->proxy->profile,
786 				   aa_get_profile(new));
787 	__aafs_profile_migrate_dents(old, new);
788 
789 	if (list_empty(&new->base.list)) {
790 		/* new is not on a list already */
791 		list_replace_rcu(&old->base.list, &new->base.list);
792 		aa_get_profile(new);
793 		aa_put_profile(old);
794 	} else
795 		__list_remove_profile(old);
796 }
797 
798 /**
799  * __lookup_replace - lookup replacement information for a profile
800  * @ns - namespace the lookup occurs in
801  * @hname - name of profile to lookup
802  * @noreplace - true if not replacing an existing profile
803  * @p - Returns: profile to be replaced
804  * @info - Returns: info string on why lookup failed
805  *
806  * Returns: profile to replace (no ref) on success else ptr error
807  */
808 static int __lookup_replace(struct aa_ns *ns, const char *hname,
809 			    bool noreplace, struct aa_profile **p,
810 			    const char **info)
811 {
812 	*p = aa_get_profile(__lookup_profile(&ns->base, hname));
813 	if (*p) {
814 		int error = replacement_allowed(*p, noreplace, info);
815 		if (error) {
816 			*info = "profile can not be replaced";
817 			return error;
818 		}
819 	}
820 
821 	return 0;
822 }
823 
824 /**
825  * aa_replace_profiles - replace profile(s) on the profile list
826  * @view: namespace load is viewed from
827  * @label: label that is attempting to load/replace policy
828  * @noreplace: true if only doing addition, no replacement allowed
829  * @udata: serialized data stream  (NOT NULL)
830  *
831  * unpack and replace a profile on the profile list and uses of that profile
832  * by any aa_task_ctx.  If the profile does not exist on the profile list
833  * it is added.
834  *
835  * Returns: size of data consumed else error code on failure.
836  */
837 ssize_t aa_replace_profiles(struct aa_ns *view, struct aa_profile *profile,
838 			    bool noreplace, struct aa_loaddata *udata)
839 {
840 	const char *ns_name, *info = NULL;
841 	struct aa_ns *ns = NULL;
842 	struct aa_load_ent *ent, *tmp;
843 	struct aa_loaddata *rawdata_ent;
844 	const char *op = OP_PROF_REPL;
845 	ssize_t count, error;
846 
847 	LIST_HEAD(lh);
848 
849 	aa_get_loaddata(udata);
850 	/* released below */
851 	error = aa_unpack(udata, &lh, &ns_name);
852 	if (error)
853 		goto out;
854 
855 	/* ensure that profiles are all for the same ns
856 	 * TODO: update locking to remove this constaint. All profiles in
857 	 *       the load set must succeed as a set or the load will
858 	 *       fail. Sort ent list and take ns locks in hierarchy order
859 	 */
860 	count = 0;
861 	list_for_each_entry(ent, &lh, list) {
862 		if (ns_name) {
863 			if (ent->ns_name &&
864 			    strcmp(ent->ns_name, ns_name) != 0) {
865 				info = "policy load has mixed namespaces";
866 				error = -EACCES;
867 				goto fail;
868 			}
869 		} else if (ent->ns_name) {
870 			if (count) {
871 				info = "policy load has mixed namespaces";
872 				error = -EACCES;
873 				goto fail;
874 			}
875 			ns_name = ent->ns_name;
876 		} else
877 			count++;
878 	}
879 	if (ns_name) {
880 		ns = aa_prepare_ns(view, ns_name);
881 		if (IS_ERR(ns)) {
882 			op = OP_PROF_LOAD;
883 			info = "failed to prepare namespace";
884 			error = PTR_ERR(ns);
885 			ns = NULL;
886 			ent = NULL;
887 			goto fail;
888 		}
889 	} else
890 		ns = aa_get_ns(view);
891 
892 	mutex_lock(&ns->lock);
893 	/* check for duplicate rawdata blobs: space and file dedup */
894 	list_for_each_entry(rawdata_ent, &ns->rawdata_list, list) {
895 		if (aa_rawdata_eq(rawdata_ent, udata)) {
896 			struct aa_loaddata *tmp;
897 
898 			tmp = __aa_get_loaddata(rawdata_ent);
899 			/* check we didn't fail the race */
900 			if (tmp) {
901 				aa_put_loaddata(udata);
902 				udata = tmp;
903 				break;
904 			}
905 		}
906 	}
907 	/* setup parent and ns info */
908 	list_for_each_entry(ent, &lh, list) {
909 		struct aa_policy *policy;
910 
911 		ent->new->rawdata = aa_get_loaddata(udata);
912 		error = __lookup_replace(ns, ent->new->base.hname, noreplace,
913 					 &ent->old, &info);
914 		if (error)
915 			goto fail_lock;
916 
917 		if (ent->new->rename) {
918 			error = __lookup_replace(ns, ent->new->rename,
919 						 noreplace, &ent->rename,
920 						 &info);
921 			if (error)
922 				goto fail_lock;
923 		}
924 
925 		/* released when @new is freed */
926 		ent->new->ns = aa_get_ns(ns);
927 
928 		if (ent->old || ent->rename)
929 			continue;
930 
931 		/* no ref on policy only use inside lock */
932 		policy = __lookup_parent(ns, ent->new->base.hname);
933 		if (!policy) {
934 			struct aa_profile *p;
935 			p = __list_lookup_parent(&lh, ent->new);
936 			if (!p) {
937 				error = -ENOENT;
938 				info = "parent does not exist";
939 				goto fail_lock;
940 			}
941 			rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
942 		} else if (policy != &ns->base) {
943 			/* released on profile replacement or free_profile */
944 			struct aa_profile *p = (struct aa_profile *) policy;
945 			rcu_assign_pointer(ent->new->parent, aa_get_profile(p));
946 		}
947 	}
948 
949 	/* create new fs entries for introspection if needed */
950 	if (!udata->dents[AAFS_LOADDATA_DIR]) {
951 		error = __aa_fs_create_rawdata(ns, udata);
952 		if (error) {
953 			info = "failed to create raw_data dir and files";
954 			ent = NULL;
955 			goto fail_lock;
956 		}
957 	}
958 	list_for_each_entry(ent, &lh, list) {
959 		if (ent->old) {
960 			/* inherit old interface files */
961 
962 			/* if (ent->rename)
963 				TODO: support rename */
964 		/* } else if (ent->rename) {
965 			TODO: support rename */
966 		} else {
967 			struct dentry *parent;
968 			if (rcu_access_pointer(ent->new->parent)) {
969 				struct aa_profile *p;
970 				p = aa_deref_parent(ent->new);
971 				parent = prof_child_dir(p);
972 			} else
973 				parent = ns_subprofs_dir(ent->new->ns);
974 			error = __aafs_profile_mkdir(ent->new, parent);
975 		}
976 
977 		if (error) {
978 			info = "failed to create ";
979 			goto fail_lock;
980 		}
981 	}
982 
983 	/* Done with checks that may fail - do actual replacement */
984 	__aa_bump_ns_revision(ns);
985 	__aa_loaddata_update(udata, ns->revision);
986 	list_for_each_entry_safe(ent, tmp, &lh, list) {
987 		list_del_init(&ent->list);
988 		op = (!ent->old && !ent->rename) ? OP_PROF_LOAD : OP_PROF_REPL;
989 
990 		if (ent->old && ent->old->rawdata == ent->new->rawdata) {
991 			/* dedup actual profile replacement */
992 			audit_policy(profile, op, ns_name, ent->new->base.hname,
993 				     "same as current profile, skipping",
994 				     error);
995 			goto skip;
996 		}
997 
998 		/*
999 		 * TODO: finer dedup based on profile range in data. Load set
1000 		 * can differ but profile may remain unchanged
1001 		 */
1002 		audit_policy(profile, op, NULL, ent->new->base.hname,
1003 			     NULL, error);
1004 
1005 		if (ent->old) {
1006 			__replace_profile(ent->old, ent->new, 1);
1007 			if (ent->rename) {
1008 				/* aafs interface uses proxy */
1009 				struct aa_proxy *r = ent->new->proxy;
1010 				rcu_assign_pointer(r->profile,
1011 						   aa_get_profile(ent->new));
1012 				__replace_profile(ent->rename, ent->new, 0);
1013 			}
1014 		} else if (ent->rename) {
1015 			/* aafs interface uses proxy */
1016 			rcu_assign_pointer(ent->new->proxy->profile,
1017 					   aa_get_profile(ent->new));
1018 			__replace_profile(ent->rename, ent->new, 0);
1019 		} else if (ent->new->parent) {
1020 			struct aa_profile *parent, *newest;
1021 			parent = aa_deref_parent(ent->new);
1022 			newest = aa_get_newest_profile(parent);
1023 
1024 			/* parent replaced in this atomic set? */
1025 			if (newest != parent) {
1026 				aa_get_profile(newest);
1027 				rcu_assign_pointer(ent->new->parent, newest);
1028 				aa_put_profile(parent);
1029 			}
1030 			/* aafs interface uses proxy */
1031 			rcu_assign_pointer(ent->new->proxy->profile,
1032 					   aa_get_profile(ent->new));
1033 			__list_add_profile(&newest->base.profiles, ent->new);
1034 			aa_put_profile(newest);
1035 		} else {
1036 			/* aafs interface uses proxy */
1037 			rcu_assign_pointer(ent->new->proxy->profile,
1038 					   aa_get_profile(ent->new));
1039 			__list_add_profile(&ns->base.profiles, ent->new);
1040 		}
1041 	skip:
1042 		aa_load_ent_free(ent);
1043 	}
1044 	mutex_unlock(&ns->lock);
1045 
1046 out:
1047 	aa_put_ns(ns);
1048 	aa_put_loaddata(udata);
1049 
1050 	if (error)
1051 		return error;
1052 	return udata->size;
1053 
1054 fail_lock:
1055 	mutex_unlock(&ns->lock);
1056 
1057 	/* audit cause of failure */
1058 	op = (ent && !ent->old) ? OP_PROF_LOAD : OP_PROF_REPL;
1059 fail:
1060 	audit_policy(profile, op, ns_name, ent ? ent->new->base.hname : NULL,
1061 		     info, error);
1062 	/* audit status that rest of profiles in the atomic set failed too */
1063 	info = "valid profile in failed atomic policy load";
1064 	list_for_each_entry(tmp, &lh, list) {
1065 		if (tmp == ent) {
1066 			info = "unchecked profile in failed atomic policy load";
1067 			/* skip entry that caused failure */
1068 			continue;
1069 		}
1070 		op = (!tmp->old) ? OP_PROF_LOAD : OP_PROF_REPL;
1071 		audit_policy(profile, op, ns_name,
1072 			     tmp->new->base.hname, info, error);
1073 	}
1074 	list_for_each_entry_safe(ent, tmp, &lh, list) {
1075 		list_del_init(&ent->list);
1076 		aa_load_ent_free(ent);
1077 	}
1078 
1079 	goto out;
1080 }
1081 
1082 /**
1083  * aa_remove_profiles - remove profile(s) from the system
1084  * @view: namespace the remove is being done from
1085  * @subj: profile attempting to remove policy
1086  * @fqname: name of the profile or namespace to remove  (NOT NULL)
1087  * @size: size of the name
1088  *
1089  * Remove a profile or sub namespace from the current namespace, so that
1090  * they can not be found anymore and mark them as replaced by unconfined
1091  *
1092  * NOTE: removing confinement does not restore rlimits to preconfinemnet values
1093  *
1094  * Returns: size of data consume else error code if fails
1095  */
1096 ssize_t aa_remove_profiles(struct aa_ns *view, struct aa_profile *subj,
1097 			   char *fqname, size_t size)
1098 {
1099 	struct aa_ns *root = NULL, *ns = NULL;
1100 	struct aa_profile *profile = NULL;
1101 	const char *name = fqname, *info = NULL;
1102 	char *ns_name = NULL;
1103 	ssize_t error = 0;
1104 
1105 	if (*fqname == 0) {
1106 		info = "no profile specified";
1107 		error = -ENOENT;
1108 		goto fail;
1109 	}
1110 
1111 	root = view;
1112 
1113 	if (fqname[0] == ':') {
1114 		name = aa_split_fqname(fqname, &ns_name);
1115 		/* released below */
1116 		ns = aa_find_ns(root, ns_name);
1117 		if (!ns) {
1118 			info = "namespace does not exist";
1119 			error = -ENOENT;
1120 			goto fail;
1121 		}
1122 	} else
1123 		/* released below */
1124 		ns = aa_get_ns(root);
1125 
1126 	if (!name) {
1127 		/* remove namespace - can only happen if fqname[0] == ':' */
1128 		mutex_lock(&ns->parent->lock);
1129 		__aa_remove_ns(ns);
1130 		__aa_bump_ns_revision(ns);
1131 		mutex_unlock(&ns->parent->lock);
1132 	} else {
1133 		/* remove profile */
1134 		mutex_lock(&ns->lock);
1135 		profile = aa_get_profile(__lookup_profile(&ns->base, name));
1136 		if (!profile) {
1137 			error = -ENOENT;
1138 			info = "profile does not exist";
1139 			goto fail_ns_lock;
1140 		}
1141 		name = profile->base.hname;
1142 		__remove_profile(profile);
1143 		__aa_bump_ns_revision(ns);
1144 		mutex_unlock(&ns->lock);
1145 	}
1146 
1147 	/* don't fail removal if audit fails */
1148 	(void) audit_policy(subj, OP_PROF_RM, ns_name, name, info,
1149 			    error);
1150 	aa_put_ns(ns);
1151 	aa_put_profile(profile);
1152 	return size;
1153 
1154 fail_ns_lock:
1155 	mutex_unlock(&ns->lock);
1156 	aa_put_ns(ns);
1157 
1158 fail:
1159 	(void) audit_policy(subj, OP_PROF_RM, ns_name, name, info,
1160 			    error);
1161 	return error;
1162 }
1163