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1 | /* |
2 | * AppArmor security module |
3 | * |
4 | * This file contains AppArmor policy manipulation functions |
5 | * |
6 | * Copyright (C) 1998-2008 Novell/SUSE |
7 | * Copyright 2009-2010 Canonical Ltd. |
8 | * |
9 | * This program is free software; you can redistribute it and/or |
10 | * modify it under the terms of the GNU General Public License as |
11 | * published by the Free Software Foundation, version 2 of the |
12 | * License. |
13 | * |
14 | * |
15 | * AppArmor policy is based around profiles, which contain the rules a |
16 | * task is confined by. Every task in the system has a profile attached |
17 | * to it determined either by matching "unconfined" tasks against the |
18 | * visible set of profiles or by following a profiles attachment rules. |
19 | * |
20 | * Each profile exists in a profile namespace which is a container of |
21 | * visible profiles. Each namespace contains a special "unconfined" profile, |
22 | * which doesn't enforce any confinement on a task beyond DAC. |
23 | * |
24 | * Namespace and profile names can be written together in either |
25 | * of two syntaxes. |
26 | * :namespace:profile - used by kernel interfaces for easy detection |
27 | * namespace://profile - used by policy |
28 | * |
29 | * Profile names can not start with : or @ or ^ and may not contain \0 |
30 | * |
31 | * Reserved profile names |
32 | * unconfined - special automatically generated unconfined profile |
33 | * inherit - special name to indicate profile inheritance |
34 | * null-XXXX-YYYY - special automatically generated learning profiles |
35 | * |
36 | * Namespace names may not start with / or @ and may not contain \0 or : |
37 | * Reserved namespace names |
38 | * user-XXXX - user defined profiles |
39 | * |
40 | * a // in a profile or namespace name indicates a hierarchical name with the |
41 | * name before the // being the parent and the name after the child. |
42 | * |
43 | * Profile and namespace hierarchies serve two different but similar purposes. |
44 | * The namespace contains the set of visible profiles that are considered |
45 | * for attachment. The hierarchy of namespaces allows for virtualizing |
46 | * the namespace so that for example a chroot can have its own set of profiles |
47 | * which may define some local user namespaces. |
48 | * The profile hierarchy severs two distinct purposes, |
49 | * - it allows for sub profiles or hats, which allows an application to run |
50 | * subprograms under its own profile with different restriction than it |
51 | * self, and not have it use the system profile. |
52 | * eg. if a mail program starts an editor, the policy might make the |
53 | * restrictions tighter on the editor tighter than the mail program, |
54 | * and definitely different than general editor restrictions |
55 | * - it allows for binary hierarchy of profiles, so that execution history |
56 | * is preserved. This feature isn't exploited by AppArmor reference policy |
57 | * but is allowed. NOTE: this is currently suboptimal because profile |
58 | * aliasing is not currently implemented so that a profile for each |
59 | * level must be defined. |
60 | * eg. /bin/bash///bin/ls as a name would indicate /bin/ls was started |
61 | * from /bin/bash |
62 | * |
63 | * A profile or namespace name that can contain one or more // separators |
64 | * is referred to as an hname (hierarchical). |
65 | * eg. /bin/bash//bin/ls |
66 | * |
67 | * An fqname is a name that may contain both namespace and profile hnames. |
68 | * eg. :ns:/bin/bash//bin/ls |
69 | * |
70 | * NOTES: |
71 | * - locking of profile lists is currently fairly coarse. All profile |
72 | * lists within a namespace use the namespace lock. |
73 | * FIXME: move profile lists to using rcu_lists |
74 | */ |
75 | |
76 | #include <linux/slab.h> |
77 | #include <linux/spinlock.h> |
78 | #include <linux/string.h> |
79 | |
80 | #include "include/apparmor.h" |
81 | #include "include/capability.h" |
82 | #include "include/context.h" |
83 | #include "include/file.h" |
84 | #include "include/ipc.h" |
85 | #include "include/match.h" |
86 | #include "include/path.h" |
87 | #include "include/policy.h" |
88 | #include "include/policy_unpack.h" |
89 | #include "include/resource.h" |
90 | |
91 | |
92 | /* root profile namespace */ |
93 | struct aa_namespace *root_ns; |
94 | |
95 | const char *const profile_mode_names[] = { |
96 | "enforce", |
97 | "complain", |
98 | "kill", |
99 | }; |
100 | |
101 | /** |
102 | * hname_tail - find the last component of an hname |
103 | * @name: hname to find the base profile name component of (NOT NULL) |
104 | * |
105 | * Returns: the tail (base profile name) name component of an hname |
106 | */ |
107 | static const char *hname_tail(const char *hname) |
108 | { |
109 | char *split; |
110 | hname = strim((char *)hname); |
111 | for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) |
112 | hname = split + 2; |
113 | |
114 | return hname; |
115 | } |
116 | |
117 | /** |
118 | * policy_init - initialize a policy structure |
119 | * @policy: policy to initialize (NOT NULL) |
120 | * @prefix: prefix name if any is required. (MAYBE NULL) |
121 | * @name: name of the policy, init will make a copy of it (NOT NULL) |
122 | * |
123 | * Note: this fn creates a copy of strings passed in |
124 | * |
125 | * Returns: true if policy init successful |
126 | */ |
127 | static bool policy_init(struct aa_policy *policy, const char *prefix, |
128 | const char *name) |
129 | { |
130 | /* freed by policy_free */ |
131 | if (prefix) { |
132 | policy->hname = kmalloc(strlen(prefix) + strlen(name) + 3, |
133 | GFP_KERNEL); |
134 | if (policy->hname) |
135 | sprintf(policy->hname, "%s//%s", prefix, name); |
136 | } else |
137 | policy->hname = kstrdup(name, GFP_KERNEL); |
138 | if (!policy->hname) |
139 | return 0; |
140 | /* base.name is a substring of fqname */ |
141 | policy->name = (char *)hname_tail(policy->hname); |
142 | INIT_LIST_HEAD(&policy->list); |
143 | INIT_LIST_HEAD(&policy->profiles); |
144 | kref_init(&policy->count); |
145 | |
146 | return 1; |
147 | } |
148 | |
149 | /** |
150 | * policy_destroy - free the elements referenced by @policy |
151 | * @policy: policy that is to have its elements freed (NOT NULL) |
152 | */ |
153 | static void policy_destroy(struct aa_policy *policy) |
154 | { |
155 | /* still contains profiles -- invalid */ |
156 | if (!list_empty(&policy->profiles)) { |
157 | AA_ERROR("%s: internal error, " |
158 | "policy '%s' still contains profiles\n", |
159 | __func__, policy->name); |
160 | BUG(); |
161 | } |
162 | if (!list_empty(&policy->list)) { |
163 | AA_ERROR("%s: internal error, policy '%s' still on list\n", |
164 | __func__, policy->name); |
165 | BUG(); |
166 | } |
167 | |
168 | /* don't free name as its a subset of hname */ |
169 | kzfree(policy->hname); |
170 | } |
171 | |
172 | /** |
173 | * __policy_find - find a policy by @name on a policy list |
174 | * @head: list to search (NOT NULL) |
175 | * @name: name to search for (NOT NULL) |
176 | * |
177 | * Requires: correct locks for the @head list be held |
178 | * |
179 | * Returns: unrefcounted policy that match @name or NULL if not found |
180 | */ |
181 | static struct aa_policy *__policy_find(struct list_head *head, const char *name) |
182 | { |
183 | struct aa_policy *policy; |
184 | |
185 | list_for_each_entry(policy, head, list) { |
186 | if (!strcmp(policy->name, name)) |
187 | return policy; |
188 | } |
189 | return NULL; |
190 | } |
191 | |
192 | /** |
193 | * __policy_strn_find - find a policy that's name matches @len chars of @str |
194 | * @head: list to search (NOT NULL) |
195 | * @str: string to search for (NOT NULL) |
196 | * @len: length of match required |
197 | * |
198 | * Requires: correct locks for the @head list be held |
199 | * |
200 | * Returns: unrefcounted policy that match @str or NULL if not found |
201 | * |
202 | * if @len == strlen(@strlen) then this is equiv to __policy_find |
203 | * other wise it allows searching for policy by a partial match of name |
204 | */ |
205 | static struct aa_policy *__policy_strn_find(struct list_head *head, |
206 | const char *str, int len) |
207 | { |
208 | struct aa_policy *policy; |
209 | |
210 | list_for_each_entry(policy, head, list) { |
211 | if (aa_strneq(policy->name, str, len)) |
212 | return policy; |
213 | } |
214 | |
215 | return NULL; |
216 | } |
217 | |
218 | /* |
219 | * Routines for AppArmor namespaces |
220 | */ |
221 | |
222 | static const char *hidden_ns_name = "---"; |
223 | /** |
224 | * aa_ns_visible - test if @view is visible from @curr |
225 | * @curr: namespace to treat as the parent (NOT NULL) |
226 | * @view: namespace to test if visible from @curr (NOT NULL) |
227 | * |
228 | * Returns: true if @view is visible from @curr else false |
229 | */ |
230 | bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view) |
231 | { |
232 | if (curr == view) |
233 | return true; |
234 | |
235 | for ( ; view; view = view->parent) { |
236 | if (view->parent == curr) |
237 | return true; |
238 | } |
239 | return false; |
240 | } |
241 | |
242 | /** |
243 | * aa_na_name - Find the ns name to display for @view from @curr |
244 | * @curr - current namespace (NOT NULL) |
245 | * @view - namespace attempting to view (NOT NULL) |
246 | * |
247 | * Returns: name of @view visible from @curr |
248 | */ |
249 | const char *aa_ns_name(struct aa_namespace *curr, struct aa_namespace *view) |
250 | { |
251 | /* if view == curr then the namespace name isn't displayed */ |
252 | if (curr == view) |
253 | return ""; |
254 | |
255 | if (aa_ns_visible(curr, view)) { |
256 | /* at this point if a ns is visible it is in a view ns |
257 | * thus the curr ns.hname is a prefix of its name. |
258 | * Only output the virtualized portion of the name |
259 | * Add + 2 to skip over // separating curr hname prefix |
260 | * from the visible tail of the views hname |
261 | */ |
262 | return view->base.hname + strlen(curr->base.hname) + 2; |
263 | } else |
264 | return hidden_ns_name; |
265 | } |
266 | |
267 | /** |
268 | * alloc_namespace - allocate, initialize and return a new namespace |
269 | * @prefix: parent namespace name (MAYBE NULL) |
270 | * @name: a preallocated name (NOT NULL) |
271 | * |
272 | * Returns: refcounted namespace or NULL on failure. |
273 | */ |
274 | static struct aa_namespace *alloc_namespace(const char *prefix, |
275 | const char *name) |
276 | { |
277 | struct aa_namespace *ns; |
278 | |
279 | ns = kzalloc(sizeof(*ns), GFP_KERNEL); |
280 | AA_DEBUG("%s(%p)\n", __func__, ns); |
281 | if (!ns) |
282 | return NULL; |
283 | if (!policy_init(&ns->base, prefix, name)) |
284 | goto fail_ns; |
285 | |
286 | INIT_LIST_HEAD(&ns->sub_ns); |
287 | rwlock_init(&ns->lock); |
288 | |
289 | /* released by free_namespace */ |
290 | ns->unconfined = aa_alloc_profile("unconfined"); |
291 | if (!ns->unconfined) |
292 | goto fail_unconfined; |
293 | |
294 | ns->unconfined->flags = PFLAG_UNCONFINED | PFLAG_IX_ON_NAME_ERROR | |
295 | PFLAG_IMMUTABLE; |
296 | |
297 | /* |
298 | * released by free_namespace, however __remove_namespace breaks |
299 | * the cyclic references (ns->unconfined, and unconfined->ns) and |
300 | * replaces with refs to parent namespace unconfined |
301 | */ |
302 | ns->unconfined->ns = aa_get_namespace(ns); |
303 | |
304 | atomic_set(&ns->uniq_null, 0); |
305 | |
306 | return ns; |
307 | |
308 | fail_unconfined: |
309 | kzfree(ns->base.hname); |
310 | fail_ns: |
311 | kzfree(ns); |
312 | return NULL; |
313 | } |
314 | |
315 | /** |
316 | * free_namespace - free a profile namespace |
317 | * @ns: the namespace to free (MAYBE NULL) |
318 | * |
319 | * Requires: All references to the namespace must have been put, if the |
320 | * namespace was referenced by a profile confining a task, |
321 | */ |
322 | static void free_namespace(struct aa_namespace *ns) |
323 | { |
324 | if (!ns) |
325 | return; |
326 | |
327 | policy_destroy(&ns->base); |
328 | aa_put_namespace(ns->parent); |
329 | |
330 | if (ns->unconfined && ns->unconfined->ns == ns) |
331 | ns->unconfined->ns = NULL; |
332 | |
333 | aa_put_profile(ns->unconfined); |
334 | kzfree(ns); |
335 | } |
336 | |
337 | /** |
338 | * aa_free_namespace_kref - free aa_namespace by kref (see aa_put_namespace) |
339 | * @kr: kref callback for freeing of a namespace (NOT NULL) |
340 | */ |
341 | void aa_free_namespace_kref(struct kref *kref) |
342 | { |
343 | free_namespace(container_of(kref, struct aa_namespace, base.count)); |
344 | } |
345 | |
346 | /** |
347 | * __aa_find_namespace - find a namespace on a list by @name |
348 | * @head: list to search for namespace on (NOT NULL) |
349 | * @name: name of namespace to look for (NOT NULL) |
350 | * |
351 | * Returns: unrefcounted namespace |
352 | * |
353 | * Requires: ns lock be held |
354 | */ |
355 | static struct aa_namespace *__aa_find_namespace(struct list_head *head, |
356 | const char *name) |
357 | { |
358 | return (struct aa_namespace *)__policy_find(head, name); |
359 | } |
360 | |
361 | /** |
362 | * aa_find_namespace - look up a profile namespace on the namespace list |
363 | * @root: namespace to search in (NOT NULL) |
364 | * @name: name of namespace to find (NOT NULL) |
365 | * |
366 | * Returns: a refcounted namespace on the list, or NULL if no namespace |
367 | * called @name exists. |
368 | * |
369 | * refcount released by caller |
370 | */ |
371 | struct aa_namespace *aa_find_namespace(struct aa_namespace *root, |
372 | const char *name) |
373 | { |
374 | struct aa_namespace *ns = NULL; |
375 | |
376 | read_lock(&root->lock); |
377 | ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name)); |
378 | read_unlock(&root->lock); |
379 | |
380 | return ns; |
381 | } |
382 | |
383 | /** |
384 | * aa_prepare_namespace - find an existing or create a new namespace of @name |
385 | * @name: the namespace to find or add (MAYBE NULL) |
386 | * |
387 | * Returns: refcounted namespace or NULL if failed to create one |
388 | */ |
389 | static struct aa_namespace *aa_prepare_namespace(const char *name) |
390 | { |
391 | struct aa_namespace *ns, *root; |
392 | |
393 | root = aa_current_profile()->ns; |
394 | |
395 | write_lock(&root->lock); |
396 | |
397 | /* if name isn't specified the profile is loaded to the current ns */ |
398 | if (!name) { |
399 | /* released by caller */ |
400 | ns = aa_get_namespace(root); |
401 | goto out; |
402 | } |
403 | |
404 | /* try and find the specified ns and if it doesn't exist create it */ |
405 | /* released by caller */ |
406 | ns = aa_get_namespace(__aa_find_namespace(&root->sub_ns, name)); |
407 | if (!ns) { |
408 | /* namespace not found */ |
409 | struct aa_namespace *new_ns; |
410 | write_unlock(&root->lock); |
411 | new_ns = alloc_namespace(root->base.hname, name); |
412 | if (!new_ns) |
413 | return NULL; |
414 | write_lock(&root->lock); |
415 | /* test for race when new_ns was allocated */ |
416 | ns = __aa_find_namespace(&root->sub_ns, name); |
417 | if (!ns) { |
418 | /* add parent ref */ |
419 | new_ns->parent = aa_get_namespace(root); |
420 | |
421 | list_add(&new_ns->base.list, &root->sub_ns); |
422 | /* add list ref */ |
423 | ns = aa_get_namespace(new_ns); |
424 | } else { |
425 | /* raced so free the new one */ |
426 | free_namespace(new_ns); |
427 | /* get reference on namespace */ |
428 | aa_get_namespace(ns); |
429 | } |
430 | } |
431 | out: |
432 | write_unlock(&root->lock); |
433 | |
434 | /* return ref */ |
435 | return ns; |
436 | } |
437 | |
438 | /** |
439 | * __list_add_profile - add a profile to a list |
440 | * @list: list to add it to (NOT NULL) |
441 | * @profile: the profile to add (NOT NULL) |
442 | * |
443 | * refcount @profile, should be put by __list_remove_profile |
444 | * |
445 | * Requires: namespace lock be held, or list not be shared |
446 | */ |
447 | static void __list_add_profile(struct list_head *list, |
448 | struct aa_profile *profile) |
449 | { |
450 | list_add(&profile->base.list, list); |
451 | /* get list reference */ |
452 | aa_get_profile(profile); |
453 | } |
454 | |
455 | /** |
456 | * __list_remove_profile - remove a profile from the list it is on |
457 | * @profile: the profile to remove (NOT NULL) |
458 | * |
459 | * remove a profile from the list, warning generally removal should |
460 | * be done with __replace_profile as most profile removals are |
461 | * replacements to the unconfined profile. |
462 | * |
463 | * put @profile list refcount |
464 | * |
465 | * Requires: namespace lock be held, or list not have been live |
466 | */ |
467 | static void __list_remove_profile(struct aa_profile *profile) |
468 | { |
469 | list_del_init(&profile->base.list); |
470 | if (!(profile->flags & PFLAG_NO_LIST_REF)) |
471 | /* release list reference */ |
472 | aa_put_profile(profile); |
473 | } |
474 | |
475 | /** |
476 | * __replace_profile - replace @old with @new on a list |
477 | * @old: profile to be replaced (NOT NULL) |
478 | * @new: profile to replace @old with (NOT NULL) |
479 | * |
480 | * Will duplicate and refcount elements that @new inherits from @old |
481 | * and will inherit @old children. |
482 | * |
483 | * refcount @new for list, put @old list refcount |
484 | * |
485 | * Requires: namespace list lock be held, or list not be shared |
486 | */ |
487 | static void __replace_profile(struct aa_profile *old, struct aa_profile *new) |
488 | { |
489 | struct aa_policy *policy; |
490 | struct aa_profile *child, *tmp; |
491 | |
492 | if (old->parent) |
493 | policy = &old->parent->base; |
494 | else |
495 | policy = &old->ns->base; |
496 | |
497 | /* released when @new is freed */ |
498 | new->parent = aa_get_profile(old->parent); |
499 | new->ns = aa_get_namespace(old->ns); |
500 | __list_add_profile(&policy->profiles, new); |
501 | /* inherit children */ |
502 | list_for_each_entry_safe(child, tmp, &old->base.profiles, base.list) { |
503 | aa_put_profile(child->parent); |
504 | child->parent = aa_get_profile(new); |
505 | /* list refcount transferred to @new*/ |
506 | list_move(&child->base.list, &new->base.profiles); |
507 | } |
508 | |
509 | /* released by free_profile */ |
510 | old->replacedby = aa_get_profile(new); |
511 | __list_remove_profile(old); |
512 | } |
513 | |
514 | static void __profile_list_release(struct list_head *head); |
515 | |
516 | /** |
517 | * __remove_profile - remove old profile, and children |
518 | * @profile: profile to be replaced (NOT NULL) |
519 | * |
520 | * Requires: namespace list lock be held, or list not be shared |
521 | */ |
522 | static void __remove_profile(struct aa_profile *profile) |
523 | { |
524 | /* release any children lists first */ |
525 | __profile_list_release(&profile->base.profiles); |
526 | /* released by free_profile */ |
527 | profile->replacedby = aa_get_profile(profile->ns->unconfined); |
528 | __list_remove_profile(profile); |
529 | } |
530 | |
531 | /** |
532 | * __profile_list_release - remove all profiles on the list and put refs |
533 | * @head: list of profiles (NOT NULL) |
534 | * |
535 | * Requires: namespace lock be held |
536 | */ |
537 | static void __profile_list_release(struct list_head *head) |
538 | { |
539 | struct aa_profile *profile, *tmp; |
540 | list_for_each_entry_safe(profile, tmp, head, base.list) |
541 | __remove_profile(profile); |
542 | } |
543 | |
544 | static void __ns_list_release(struct list_head *head); |
545 | |
546 | /** |
547 | * destroy_namespace - remove everything contained by @ns |
548 | * @ns: namespace to have it contents removed (NOT NULL) |
549 | */ |
550 | static void destroy_namespace(struct aa_namespace *ns) |
551 | { |
552 | if (!ns) |
553 | return; |
554 | |
555 | write_lock(&ns->lock); |
556 | /* release all profiles in this namespace */ |
557 | __profile_list_release(&ns->base.profiles); |
558 | |
559 | /* release all sub namespaces */ |
560 | __ns_list_release(&ns->sub_ns); |
561 | |
562 | write_unlock(&ns->lock); |
563 | } |
564 | |
565 | /** |
566 | * __remove_namespace - remove a namespace and all its children |
567 | * @ns: namespace to be removed (NOT NULL) |
568 | * |
569 | * Requires: ns->parent->lock be held and ns removed from parent. |
570 | */ |
571 | static void __remove_namespace(struct aa_namespace *ns) |
572 | { |
573 | struct aa_profile *unconfined = ns->unconfined; |
574 | |
575 | /* remove ns from namespace list */ |
576 | list_del_init(&ns->base.list); |
577 | |
578 | /* |
579 | * break the ns, unconfined profile cyclic reference and forward |
580 | * all new unconfined profiles requests to the parent namespace |
581 | * This will result in all confined tasks that have a profile |
582 | * being removed, inheriting the parent->unconfined profile. |
583 | */ |
584 | if (ns->parent) |
585 | ns->unconfined = aa_get_profile(ns->parent->unconfined); |
586 | |
587 | destroy_namespace(ns); |
588 | |
589 | /* release original ns->unconfined ref */ |
590 | aa_put_profile(unconfined); |
591 | /* release ns->base.list ref, from removal above */ |
592 | aa_put_namespace(ns); |
593 | } |
594 | |
595 | /** |
596 | * __ns_list_release - remove all profile namespaces on the list put refs |
597 | * @head: list of profile namespaces (NOT NULL) |
598 | * |
599 | * Requires: namespace lock be held |
600 | */ |
601 | static void __ns_list_release(struct list_head *head) |
602 | { |
603 | struct aa_namespace *ns, *tmp; |
604 | list_for_each_entry_safe(ns, tmp, head, base.list) |
605 | __remove_namespace(ns); |
606 | |
607 | } |
608 | |
609 | /** |
610 | * aa_alloc_root_ns - allocate the root profile namespace |
611 | * |
612 | * Returns: %0 on success else error |
613 | * |
614 | */ |
615 | int __init aa_alloc_root_ns(void) |
616 | { |
617 | /* released by aa_free_root_ns - used as list ref*/ |
618 | root_ns = alloc_namespace(NULL, "root"); |
619 | if (!root_ns) |
620 | return -ENOMEM; |
621 | |
622 | return 0; |
623 | } |
624 | |
625 | /** |
626 | * aa_free_root_ns - free the root profile namespace |
627 | */ |
628 | void __init aa_free_root_ns(void) |
629 | { |
630 | struct aa_namespace *ns = root_ns; |
631 | root_ns = NULL; |
632 | |
633 | destroy_namespace(ns); |
634 | aa_put_namespace(ns); |
635 | } |
636 | |
637 | /** |
638 | * free_profile - free a profile |
639 | * @profile: the profile to free (MAYBE NULL) |
640 | * |
641 | * Free a profile, its hats and null_profile. All references to the profile, |
642 | * its hats and null_profile must have been put. |
643 | * |
644 | * If the profile was referenced from a task context, free_profile() will |
645 | * be called from an rcu callback routine, so we must not sleep here. |
646 | */ |
647 | static void free_profile(struct aa_profile *profile) |
648 | { |
649 | struct aa_profile *p; |
650 | |
651 | AA_DEBUG("%s(%p)\n", __func__, profile); |
652 | |
653 | if (!profile) |
654 | return; |
655 | |
656 | if (!list_empty(&profile->base.list)) { |
657 | AA_ERROR("%s: internal error, " |
658 | "profile '%s' still on ns list\n", |
659 | __func__, profile->base.name); |
660 | BUG(); |
661 | } |
662 | |
663 | /* free children profiles */ |
664 | policy_destroy(&profile->base); |
665 | aa_put_profile(profile->parent); |
666 | |
667 | aa_put_namespace(profile->ns); |
668 | kzfree(profile->rename); |
669 | |
670 | aa_free_file_rules(&profile->file); |
671 | aa_free_cap_rules(&profile->caps); |
672 | aa_free_rlimit_rules(&profile->rlimits); |
673 | |
674 | aa_put_dfa(profile->xmatch); |
675 | aa_put_dfa(profile->policy.dfa); |
676 | |
677 | /* put the profile reference for replacedby, but not via |
678 | * put_profile(kref_put). |
679 | * replacedby can form a long chain that can result in cascading |
680 | * frees that blows the stack because kref_put makes a nested fn |
681 | * call (it looks like recursion, with free_profile calling |
682 | * free_profile) for each profile in the chain lp#1056078. |
683 | */ |
684 | for (p = profile->replacedby; p; ) { |
685 | if (atomic_dec_and_test(&p->base.count.refcount)) { |
686 | /* no more refs on p, grab its replacedby */ |
687 | struct aa_profile *next = p->replacedby; |
688 | /* break the chain */ |
689 | p->replacedby = NULL; |
690 | /* now free p, chain is broken */ |
691 | free_profile(p); |
692 | |
693 | /* follow up with next profile in the chain */ |
694 | p = next; |
695 | } else |
696 | break; |
697 | } |
698 | |
699 | kzfree(profile); |
700 | } |
701 | |
702 | /** |
703 | * aa_free_profile_kref - free aa_profile by kref (called by aa_put_profile) |
704 | * @kr: kref callback for freeing of a profile (NOT NULL) |
705 | */ |
706 | void aa_free_profile_kref(struct kref *kref) |
707 | { |
708 | struct aa_profile *p = container_of(kref, struct aa_profile, |
709 | base.count); |
710 | |
711 | free_profile(p); |
712 | } |
713 | |
714 | /** |
715 | * aa_alloc_profile - allocate, initialize and return a new profile |
716 | * @hname: name of the profile (NOT NULL) |
717 | * |
718 | * Returns: refcount profile or NULL on failure |
719 | */ |
720 | struct aa_profile *aa_alloc_profile(const char *hname) |
721 | { |
722 | struct aa_profile *profile; |
723 | |
724 | /* freed by free_profile - usually through aa_put_profile */ |
725 | profile = kzalloc(sizeof(*profile), GFP_KERNEL); |
726 | if (!profile) |
727 | return NULL; |
728 | |
729 | if (!policy_init(&profile->base, NULL, hname)) { |
730 | kzfree(profile); |
731 | return NULL; |
732 | } |
733 | |
734 | /* refcount released by caller */ |
735 | return profile; |
736 | } |
737 | |
738 | /** |
739 | * aa_new_null_profile - create a new null-X learning profile |
740 | * @parent: profile that caused this profile to be created (NOT NULL) |
741 | * @hat: true if the null- learning profile is a hat |
742 | * |
743 | * Create a null- complain mode profile used in learning mode. The name of |
744 | * the profile is unique and follows the format of parent//null-<uniq>. |
745 | * |
746 | * null profiles are added to the profile list but the list does not |
747 | * hold a count on them so that they are automatically released when |
748 | * not in use. |
749 | * |
750 | * Returns: new refcounted profile else NULL on failure |
751 | */ |
752 | struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat) |
753 | { |
754 | struct aa_profile *profile = NULL; |
755 | char *name; |
756 | int uniq = atomic_inc_return(&parent->ns->uniq_null); |
757 | |
758 | /* freed below */ |
759 | name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, GFP_KERNEL); |
760 | if (!name) |
761 | goto fail; |
762 | sprintf(name, "%s//null-%x", parent->base.hname, uniq); |
763 | |
764 | profile = aa_alloc_profile(name); |
765 | kfree(name); |
766 | if (!profile) |
767 | goto fail; |
768 | |
769 | profile->mode = APPARMOR_COMPLAIN; |
770 | profile->flags = PFLAG_NULL; |
771 | if (hat) |
772 | profile->flags |= PFLAG_HAT; |
773 | |
774 | /* released on free_profile */ |
775 | profile->parent = aa_get_profile(parent); |
776 | profile->ns = aa_get_namespace(parent->ns); |
777 | |
778 | write_lock(&profile->ns->lock); |
779 | __list_add_profile(&parent->base.profiles, profile); |
780 | write_unlock(&profile->ns->lock); |
781 | |
782 | /* refcount released by caller */ |
783 | return profile; |
784 | |
785 | fail: |
786 | return NULL; |
787 | } |
788 | |
789 | /* TODO: profile accounting - setup in remove */ |
790 | |
791 | /** |
792 | * __find_child - find a profile on @head list with a name matching @name |
793 | * @head: list to search (NOT NULL) |
794 | * @name: name of profile (NOT NULL) |
795 | * |
796 | * Requires: ns lock protecting list be held |
797 | * |
798 | * Returns: unrefcounted profile ptr, or NULL if not found |
799 | */ |
800 | static struct aa_profile *__find_child(struct list_head *head, const char *name) |
801 | { |
802 | return (struct aa_profile *)__policy_find(head, name); |
803 | } |
804 | |
805 | /** |
806 | * __strn_find_child - find a profile on @head list using substring of @name |
807 | * @head: list to search (NOT NULL) |
808 | * @name: name of profile (NOT NULL) |
809 | * @len: length of @name substring to match |
810 | * |
811 | * Requires: ns lock protecting list be held |
812 | * |
813 | * Returns: unrefcounted profile ptr, or NULL if not found |
814 | */ |
815 | static struct aa_profile *__strn_find_child(struct list_head *head, |
816 | const char *name, int len) |
817 | { |
818 | return (struct aa_profile *)__policy_strn_find(head, name, len); |
819 | } |
820 | |
821 | /** |
822 | * aa_find_child - find a profile by @name in @parent |
823 | * @parent: profile to search (NOT NULL) |
824 | * @name: profile name to search for (NOT NULL) |
825 | * |
826 | * Returns: a refcounted profile or NULL if not found |
827 | */ |
828 | struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name) |
829 | { |
830 | struct aa_profile *profile; |
831 | |
832 | read_lock(&parent->ns->lock); |
833 | profile = aa_get_profile(__find_child(&parent->base.profiles, name)); |
834 | read_unlock(&parent->ns->lock); |
835 | |
836 | /* refcount released by caller */ |
837 | return profile; |
838 | } |
839 | |
840 | /** |
841 | * __lookup_parent - lookup the parent of a profile of name @hname |
842 | * @ns: namespace to lookup profile in (NOT NULL) |
843 | * @hname: hierarchical profile name to find parent of (NOT NULL) |
844 | * |
845 | * Lookups up the parent of a fully qualified profile name, the profile |
846 | * that matches hname does not need to exist, in general this |
847 | * is used to load a new profile. |
848 | * |
849 | * Requires: ns->lock be held |
850 | * |
851 | * Returns: unrefcounted policy or NULL if not found |
852 | */ |
853 | static struct aa_policy *__lookup_parent(struct aa_namespace *ns, |
854 | const char *hname) |
855 | { |
856 | struct aa_policy *policy; |
857 | struct aa_profile *profile = NULL; |
858 | char *split; |
859 | |
860 | policy = &ns->base; |
861 | |
862 | for (split = strstr(hname, "//"); split;) { |
863 | profile = __strn_find_child(&policy->profiles, hname, |
864 | split - hname); |
865 | if (!profile) |
866 | return NULL; |
867 | policy = &profile->base; |
868 | hname = split + 2; |
869 | split = strstr(hname, "//"); |
870 | } |
871 | if (!profile) |
872 | return &ns->base; |
873 | return &profile->base; |
874 | } |
875 | |
876 | /** |
877 | * __lookup_profile - lookup the profile matching @hname |
878 | * @base: base list to start looking up profile name from (NOT NULL) |
879 | * @hname: hierarchical profile name (NOT NULL) |
880 | * |
881 | * Requires: ns->lock be held |
882 | * |
883 | * Returns: unrefcounted profile pointer or NULL if not found |
884 | * |
885 | * Do a relative name lookup, recursing through profile tree. |
886 | */ |
887 | static struct aa_profile *__lookup_profile(struct aa_policy *base, |
888 | const char *hname) |
889 | { |
890 | struct aa_profile *profile = NULL; |
891 | char *split; |
892 | |
893 | for (split = strstr(hname, "//"); split;) { |
894 | profile = __strn_find_child(&base->profiles, hname, |
895 | split - hname); |
896 | if (!profile) |
897 | return NULL; |
898 | |
899 | base = &profile->base; |
900 | hname = split + 2; |
901 | split = strstr(hname, "//"); |
902 | } |
903 | |
904 | profile = __find_child(&base->profiles, hname); |
905 | |
906 | return profile; |
907 | } |
908 | |
909 | /** |
910 | * aa_lookup_profile - find a profile by its full or partial name |
911 | * @ns: the namespace to start from (NOT NULL) |
912 | * @hname: name to do lookup on. Does not contain namespace prefix (NOT NULL) |
913 | * |
914 | * Returns: refcounted profile or NULL if not found |
915 | */ |
916 | struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *hname) |
917 | { |
918 | struct aa_profile *profile; |
919 | |
920 | read_lock(&ns->lock); |
921 | profile = aa_get_profile(__lookup_profile(&ns->base, hname)); |
922 | read_unlock(&ns->lock); |
923 | |
924 | /* the unconfined profile is not in the regular profile list */ |
925 | if (!profile && strcmp(hname, "unconfined") == 0) |
926 | profile = aa_get_profile(ns->unconfined); |
927 | |
928 | /* refcount released by caller */ |
929 | return profile; |
930 | } |
931 | |
932 | /** |
933 | * replacement_allowed - test to see if replacement is allowed |
934 | * @profile: profile to test if it can be replaced (MAYBE NULL) |
935 | * @noreplace: true if replacement shouldn't be allowed but addition is okay |
936 | * @info: Returns - info about why replacement failed (NOT NULL) |
937 | * |
938 | * Returns: %0 if replacement allowed else error code |
939 | */ |
940 | static int replacement_allowed(struct aa_profile *profile, int noreplace, |
941 | const char **info) |
942 | { |
943 | if (profile) { |
944 | if (profile->flags & PFLAG_IMMUTABLE) { |
945 | *info = "cannot replace immutible profile"; |
946 | return -EPERM; |
947 | } else if (noreplace) { |
948 | *info = "profile already exists"; |
949 | return -EEXIST; |
950 | } |
951 | } |
952 | return 0; |
953 | } |
954 | |
955 | /** |
956 | * __add_new_profile - simple wrapper around __list_add_profile |
957 | * @ns: namespace that profile is being added to (NOT NULL) |
958 | * @policy: the policy container to add the profile to (NOT NULL) |
959 | * @profile: profile to add (NOT NULL) |
960 | * |
961 | * add a profile to a list and do other required basic allocations |
962 | */ |
963 | static void __add_new_profile(struct aa_namespace *ns, struct aa_policy *policy, |
964 | struct aa_profile *profile) |
965 | { |
966 | if (policy != &ns->base) |
967 | /* released on profile replacement or free_profile */ |
968 | profile->parent = aa_get_profile((struct aa_profile *) policy); |
969 | __list_add_profile(&policy->profiles, profile); |
970 | /* released on free_profile */ |
971 | profile->ns = aa_get_namespace(ns); |
972 | } |
973 | |
974 | /** |
975 | * aa_audit_policy - Do auditing of policy changes |
976 | * @op: policy operation being performed |
977 | * @gfp: memory allocation flags |
978 | * @name: name of profile being manipulated (NOT NULL) |
979 | * @info: any extra information to be audited (MAYBE NULL) |
980 | * @error: error code |
981 | * |
982 | * Returns: the error to be returned after audit is done |
983 | */ |
984 | static int audit_policy(int op, gfp_t gfp, const char *name, const char *info, |
985 | int error) |
986 | { |
987 | struct common_audit_data sa; |
988 | struct apparmor_audit_data aad = {0,}; |
989 | sa.type = LSM_AUDIT_DATA_NONE; |
990 | sa.aad = &aad; |
991 | aad.op = op; |
992 | aad.name = name; |
993 | aad.info = info; |
994 | aad.error = error; |
995 | |
996 | return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp, |
997 | &sa, NULL); |
998 | } |
999 | |
1000 | /** |
1001 | * aa_may_manage_policy - can the current task manage policy |
1002 | * @op: the policy manipulation operation being done |
1003 | * |
1004 | * Returns: true if the task is allowed to manipulate policy |
1005 | */ |
1006 | bool aa_may_manage_policy(int op) |
1007 | { |
1008 | /* check if loading policy is locked out */ |
1009 | if (aa_g_lock_policy) { |
1010 | audit_policy(op, GFP_KERNEL, NULL, "policy_locked", -EACCES); |
1011 | return 0; |
1012 | } |
1013 | |
1014 | if (!capable(CAP_MAC_ADMIN)) { |
1015 | audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES); |
1016 | return 0; |
1017 | } |
1018 | |
1019 | return 1; |
1020 | } |
1021 | |
1022 | /** |
1023 | * aa_replace_profiles - replace profile(s) on the profile list |
1024 | * @udata: serialized data stream (NOT NULL) |
1025 | * @size: size of the serialized data stream |
1026 | * @noreplace: true if only doing addition, no replacement allowed |
1027 | * |
1028 | * unpack and replace a profile on the profile list and uses of that profile |
1029 | * by any aa_task_cxt. If the profile does not exist on the profile list |
1030 | * it is added. |
1031 | * |
1032 | * Returns: size of data consumed else error code on failure. |
1033 | */ |
1034 | ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace) |
1035 | { |
1036 | struct aa_policy *policy; |
1037 | struct aa_profile *old_profile = NULL, *new_profile = NULL; |
1038 | struct aa_profile *rename_profile = NULL; |
1039 | struct aa_namespace *ns = NULL; |
1040 | const char *ns_name, *name = NULL, *info = NULL; |
1041 | int op = OP_PROF_REPL; |
1042 | ssize_t error; |
1043 | |
1044 | /* released below */ |
1045 | new_profile = aa_unpack(udata, size, &ns_name); |
1046 | if (IS_ERR(new_profile)) { |
1047 | error = PTR_ERR(new_profile); |
1048 | new_profile = NULL; |
1049 | goto fail; |
1050 | } |
1051 | |
1052 | /* released below */ |
1053 | ns = aa_prepare_namespace(ns_name); |
1054 | if (!ns) { |
1055 | info = "failed to prepare namespace"; |
1056 | error = -ENOMEM; |
1057 | name = ns_name; |
1058 | goto fail; |
1059 | } |
1060 | |
1061 | name = new_profile->base.hname; |
1062 | |
1063 | write_lock(&ns->lock); |
1064 | /* no ref on policy only use inside lock */ |
1065 | policy = __lookup_parent(ns, new_profile->base.hname); |
1066 | |
1067 | if (!policy) { |
1068 | info = "parent does not exist"; |
1069 | error = -ENOENT; |
1070 | goto audit; |
1071 | } |
1072 | |
1073 | old_profile = __find_child(&policy->profiles, new_profile->base.name); |
1074 | /* released below */ |
1075 | aa_get_profile(old_profile); |
1076 | |
1077 | if (new_profile->rename) { |
1078 | rename_profile = __lookup_profile(&ns->base, |
1079 | new_profile->rename); |
1080 | /* released below */ |
1081 | aa_get_profile(rename_profile); |
1082 | |
1083 | if (!rename_profile) { |
1084 | info = "profile to rename does not exist"; |
1085 | name = new_profile->rename; |
1086 | error = -ENOENT; |
1087 | goto audit; |
1088 | } |
1089 | } |
1090 | |
1091 | error = replacement_allowed(old_profile, noreplace, &info); |
1092 | if (error) |
1093 | goto audit; |
1094 | |
1095 | error = replacement_allowed(rename_profile, noreplace, &info); |
1096 | if (error) |
1097 | goto audit; |
1098 | |
1099 | audit: |
1100 | if (!old_profile && !rename_profile) |
1101 | op = OP_PROF_LOAD; |
1102 | |
1103 | error = audit_policy(op, GFP_ATOMIC, name, info, error); |
1104 | |
1105 | if (!error) { |
1106 | if (rename_profile) |
1107 | __replace_profile(rename_profile, new_profile); |
1108 | if (old_profile) |
1109 | __replace_profile(old_profile, new_profile); |
1110 | if (!(old_profile || rename_profile)) |
1111 | __add_new_profile(ns, policy, new_profile); |
1112 | } |
1113 | write_unlock(&ns->lock); |
1114 | |
1115 | out: |
1116 | aa_put_namespace(ns); |
1117 | aa_put_profile(rename_profile); |
1118 | aa_put_profile(old_profile); |
1119 | aa_put_profile(new_profile); |
1120 | if (error) |
1121 | return error; |
1122 | return size; |
1123 | |
1124 | fail: |
1125 | error = audit_policy(op, GFP_KERNEL, name, info, error); |
1126 | goto out; |
1127 | } |
1128 | |
1129 | /** |
1130 | * aa_remove_profiles - remove profile(s) from the system |
1131 | * @fqname: name of the profile or namespace to remove (NOT NULL) |
1132 | * @size: size of the name |
1133 | * |
1134 | * Remove a profile or sub namespace from the current namespace, so that |
1135 | * they can not be found anymore and mark them as replaced by unconfined |
1136 | * |
1137 | * NOTE: removing confinement does not restore rlimits to preconfinemnet values |
1138 | * |
1139 | * Returns: size of data consume else error code if fails |
1140 | */ |
1141 | ssize_t aa_remove_profiles(char *fqname, size_t size) |
1142 | { |
1143 | struct aa_namespace *root, *ns = NULL; |
1144 | struct aa_profile *profile = NULL; |
1145 | const char *name = fqname, *info = NULL; |
1146 | ssize_t error = 0; |
1147 | |
1148 | if (*fqname == 0) { |
1149 | info = "no profile specified"; |
1150 | error = -ENOENT; |
1151 | goto fail; |
1152 | } |
1153 | |
1154 | root = aa_current_profile()->ns; |
1155 | |
1156 | if (fqname[0] == ':') { |
1157 | char *ns_name; |
1158 | name = aa_split_fqname(fqname, &ns_name); |
1159 | /* released below */ |
1160 | ns = aa_find_namespace(root, ns_name); |
1161 | if (!ns) { |
1162 | info = "namespace does not exist"; |
1163 | error = -ENOENT; |
1164 | goto fail; |
1165 | } |
1166 | } else |
1167 | /* released below */ |
1168 | ns = aa_get_namespace(root); |
1169 | |
1170 | if (!name) { |
1171 | /* remove namespace - can only happen if fqname[0] == ':' */ |
1172 | write_lock(&ns->parent->lock); |
1173 | __remove_namespace(ns); |
1174 | write_unlock(&ns->parent->lock); |
1175 | } else { |
1176 | /* remove profile */ |
1177 | write_lock(&ns->lock); |
1178 | profile = aa_get_profile(__lookup_profile(&ns->base, name)); |
1179 | if (!profile) { |
1180 | error = -ENOENT; |
1181 | info = "profile does not exist"; |
1182 | goto fail_ns_lock; |
1183 | } |
1184 | name = profile->base.hname; |
1185 | __remove_profile(profile); |
1186 | write_unlock(&ns->lock); |
1187 | } |
1188 | |
1189 | /* don't fail removal if audit fails */ |
1190 | (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error); |
1191 | aa_put_namespace(ns); |
1192 | aa_put_profile(profile); |
1193 | return size; |
1194 | |
1195 | fail_ns_lock: |
1196 | write_unlock(&ns->lock); |
1197 | aa_put_namespace(ns); |
1198 | |
1199 | fail: |
1200 | (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error); |
1201 | return error; |
1202 | } |
1203 |
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