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c88d4c7b JJ |
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 | #include "include/sid.h" | |
91 | ||
92 | ||
93 | /* root profile namespace */ | |
94 | struct aa_namespace *root_ns; | |
95 | ||
2d4cee7e | 96 | const char *const profile_mode_names[] = { |
c88d4c7b JJ |
97 | "enforce", |
98 | "complain", | |
99 | "kill", | |
100 | }; | |
101 | ||
102 | /** | |
103 | * hname_tail - find the last component of an hname | |
104 | * @name: hname to find the base profile name component of (NOT NULL) | |
105 | * | |
106 | * Returns: the tail (base profile name) name component of an hname | |
107 | */ | |
108 | static const char *hname_tail(const char *hname) | |
109 | { | |
110 | char *split; | |
111 | hname = strim((char *)hname); | |
112 | for (split = strstr(hname, "//"); split; split = strstr(hname, "//")) | |
113 | hname = split + 2; | |
114 | ||
115 | return hname; | |
116 | } | |
117 | ||
118 | /** | |
119 | * policy_init - initialize a policy structure | |
120 | * @policy: policy to initialize (NOT NULL) | |
121 | * @prefix: prefix name if any is required. (MAYBE NULL) | |
122 | * @name: name of the policy, init will make a copy of it (NOT NULL) | |
123 | * | |
124 | * Note: this fn creates a copy of strings passed in | |
125 | * | |
126 | * Returns: true if policy init successful | |
127 | */ | |
128 | static bool policy_init(struct aa_policy *policy, const char *prefix, | |
129 | const char *name) | |
130 | { | |
131 | /* freed by policy_free */ | |
132 | if (prefix) { | |
133 | policy->hname = kmalloc(strlen(prefix) + strlen(name) + 3, | |
134 | GFP_KERNEL); | |
135 | if (policy->hname) | |
136 | sprintf(policy->hname, "%s//%s", prefix, name); | |
137 | } else | |
138 | policy->hname = kstrdup(name, GFP_KERNEL); | |
139 | if (!policy->hname) | |
140 | return 0; | |
141 | /* base.name is a substring of fqname */ | |
142 | policy->name = (char *)hname_tail(policy->hname); | |
143 | INIT_LIST_HEAD(&policy->list); | |
144 | INIT_LIST_HEAD(&policy->profiles); | |
145 | kref_init(&policy->count); | |
146 | ||
147 | return 1; | |
148 | } | |
149 | ||
150 | /** | |
151 | * policy_destroy - free the elements referenced by @policy | |
152 | * @policy: policy that is to have its elements freed (NOT NULL) | |
153 | */ | |
154 | static void policy_destroy(struct aa_policy *policy) | |
155 | { | |
156 | /* still contains profiles -- invalid */ | |
157 | if (!list_empty(&policy->profiles)) { | |
158 | AA_ERROR("%s: internal error, " | |
159 | "policy '%s' still contains profiles\n", | |
160 | __func__, policy->name); | |
161 | BUG(); | |
162 | } | |
163 | if (!list_empty(&policy->list)) { | |
164 | AA_ERROR("%s: internal error, policy '%s' still on list\n", | |
165 | __func__, policy->name); | |
166 | BUG(); | |
167 | } | |
168 | ||
169 | /* don't free name as its a subset of hname */ | |
170 | kzfree(policy->hname); | |
171 | } | |
172 | ||
173 | /** | |
174 | * __policy_find - find a policy by @name on a policy list | |
175 | * @head: list to search (NOT NULL) | |
176 | * @name: name to search for (NOT NULL) | |
177 | * | |
178 | * Requires: correct locks for the @head list be held | |
179 | * | |
180 | * Returns: unrefcounted policy that match @name or NULL if not found | |
181 | */ | |
182 | static struct aa_policy *__policy_find(struct list_head *head, const char *name) | |
183 | { | |
184 | struct aa_policy *policy; | |
185 | ||
186 | list_for_each_entry(policy, head, list) { | |
187 | if (!strcmp(policy->name, name)) | |
188 | return policy; | |
189 | } | |
190 | return NULL; | |
191 | } | |
192 | ||
193 | /** | |
194 | * __policy_strn_find - find a policy that's name matches @len chars of @str | |
195 | * @head: list to search (NOT NULL) | |
196 | * @str: string to search for (NOT NULL) | |
197 | * @len: length of match required | |
198 | * | |
199 | * Requires: correct locks for the @head list be held | |
200 | * | |
201 | * Returns: unrefcounted policy that match @str or NULL if not found | |
202 | * | |
203 | * if @len == strlen(@strlen) then this is equiv to __policy_find | |
204 | * other wise it allows searching for policy by a partial match of name | |
205 | */ | |
206 | static struct aa_policy *__policy_strn_find(struct list_head *head, | |
207 | const char *str, int len) | |
208 | { | |
209 | struct aa_policy *policy; | |
210 | ||
211 | list_for_each_entry(policy, head, list) { | |
212 | if (aa_strneq(policy->name, str, len)) | |
213 | return policy; | |
214 | } | |
215 | ||
216 | return NULL; | |
217 | } | |
218 | ||
219 | /* | |
220 | * Routines for AppArmor namespaces | |
221 | */ | |
222 | ||
223 | static const char *hidden_ns_name = "---"; | |
224 | /** | |
225 | * aa_ns_visible - test if @view is visible from @curr | |
226 | * @curr: namespace to treat as the parent (NOT NULL) | |
227 | * @view: namespace to test if visible from @curr (NOT NULL) | |
228 | * | |
229 | * Returns: true if @view is visible from @curr else false | |
230 | */ | |
231 | bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view) | |
232 | { | |
233 | if (curr == view) | |
234 | return true; | |
235 | ||
236 | for ( ; view; view = view->parent) { | |
237 | if (view->parent == curr) | |
238 | return true; | |
239 | } | |
240 | return false; | |
241 | } | |
242 | ||
243 | /** | |
244 | * aa_na_name - Find the ns name to display for @view from @curr | |
245 | * @curr - current namespace (NOT NULL) | |
246 | * @view - namespace attempting to view (NOT NULL) | |
247 | * | |
248 | * Returns: name of @view visible from @curr | |
249 | */ | |
250 | const char *aa_ns_name(struct aa_namespace *curr, struct aa_namespace *view) | |
251 | { | |
252 | /* if view == curr then the namespace name isn't displayed */ | |
253 | if (curr == view) | |
254 | return ""; | |
255 | ||
256 | if (aa_ns_visible(curr, view)) { | |
257 | /* at this point if a ns is visible it is in a view ns | |
258 | * thus the curr ns.hname is a prefix of its name. | |
259 | * Only output the virtualized portion of the name | |
260 | * Add + 2 to skip over // separating curr hname prefix | |
261 | * from the visible tail of the views hname | |
262 | */ | |
263 | return view->base.hname + strlen(curr->base.hname) + 2; | |
264 | } else | |
265 | return hidden_ns_name; | |
266 | } | |
267 | ||
268 | /** | |
269 | * alloc_namespace - allocate, initialize and return a new namespace | |
270 | * @prefix: parent namespace name (MAYBE NULL) | |
271 | * @name: a preallocated name (NOT NULL) | |
272 | * | |
273 | * Returns: refcounted namespace or NULL on failure. | |
274 | */ | |
275 | static struct aa_namespace *alloc_namespace(const char *prefix, | |
276 | const char *name) | |
277 | { | |
278 | struct aa_namespace *ns; | |
279 | ||
280 | ns = kzalloc(sizeof(*ns), GFP_KERNEL); | |
281 | AA_DEBUG("%s(%p)\n", __func__, ns); | |
282 | if (!ns) | |
283 | return NULL; | |
284 | if (!policy_init(&ns->base, prefix, name)) | |
285 | goto fail_ns; | |
286 | ||
287 | INIT_LIST_HEAD(&ns->sub_ns); | |
288 | rwlock_init(&ns->lock); | |
289 | ||
290 | /* released by free_namespace */ | |
291 | ns->unconfined = aa_alloc_profile("unconfined"); | |
292 | if (!ns->unconfined) | |
293 | goto fail_unconfined; | |
294 | ||
295 | ns->unconfined->sid = aa_alloc_sid(); | |
296 | ns->unconfined->flags = PFLAG_UNCONFINED | PFLAG_IX_ON_NAME_ERROR | | |
297 | PFLAG_IMMUTABLE; | |
298 | ||
299 | /* | |
300 | * released by free_namespace, however __remove_namespace breaks | |
301 | * the cyclic references (ns->unconfined, and unconfined->ns) and | |
302 | * replaces with refs to parent namespace unconfined | |
303 | */ | |
304 | ns->unconfined->ns = aa_get_namespace(ns); | |
305 | ||
306 | return ns; | |
307 | ||
308 | fail_unconfined: | |
246c3fb1 | 309 | kzfree(ns->base.hname); |
c88d4c7b JJ |
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 | new->sid = old->sid; | |
501 | __list_add_profile(&policy->profiles, new); | |
502 | /* inherit children */ | |
503 | list_for_each_entry_safe(child, tmp, &old->base.profiles, base.list) { | |
504 | aa_put_profile(child->parent); | |
505 | child->parent = aa_get_profile(new); | |
506 | /* list refcount transferred to @new*/ | |
507 | list_move(&child->base.list, &new->base.profiles); | |
508 | } | |
509 | ||
510 | /* released by free_profile */ | |
511 | old->replacedby = aa_get_profile(new); | |
512 | __list_remove_profile(old); | |
513 | } | |
514 | ||
515 | static void __profile_list_release(struct list_head *head); | |
516 | ||
517 | /** | |
518 | * __remove_profile - remove old profile, and children | |
519 | * @profile: profile to be replaced (NOT NULL) | |
520 | * | |
521 | * Requires: namespace list lock be held, or list not be shared | |
522 | */ | |
523 | static void __remove_profile(struct aa_profile *profile) | |
524 | { | |
525 | /* release any children lists first */ | |
526 | __profile_list_release(&profile->base.profiles); | |
527 | /* released by free_profile */ | |
528 | profile->replacedby = aa_get_profile(profile->ns->unconfined); | |
529 | __list_remove_profile(profile); | |
530 | } | |
531 | ||
532 | /** | |
533 | * __profile_list_release - remove all profiles on the list and put refs | |
534 | * @head: list of profiles (NOT NULL) | |
535 | * | |
536 | * Requires: namespace lock be held | |
537 | */ | |
538 | static void __profile_list_release(struct list_head *head) | |
539 | { | |
540 | struct aa_profile *profile, *tmp; | |
541 | list_for_each_entry_safe(profile, tmp, head, base.list) | |
542 | __remove_profile(profile); | |
543 | } | |
544 | ||
545 | static void __ns_list_release(struct list_head *head); | |
546 | ||
547 | /** | |
548 | * destroy_namespace - remove everything contained by @ns | |
549 | * @ns: namespace to have it contents removed (NOT NULL) | |
550 | */ | |
551 | static void destroy_namespace(struct aa_namespace *ns) | |
552 | { | |
553 | if (!ns) | |
554 | return; | |
555 | ||
556 | write_lock(&ns->lock); | |
557 | /* release all profiles in this namespace */ | |
558 | __profile_list_release(&ns->base.profiles); | |
559 | ||
560 | /* release all sub namespaces */ | |
561 | __ns_list_release(&ns->sub_ns); | |
562 | ||
563 | write_unlock(&ns->lock); | |
564 | } | |
565 | ||
566 | /** | |
567 | * __remove_namespace - remove a namespace and all its children | |
568 | * @ns: namespace to be removed (NOT NULL) | |
569 | * | |
570 | * Requires: ns->parent->lock be held and ns removed from parent. | |
571 | */ | |
572 | static void __remove_namespace(struct aa_namespace *ns) | |
573 | { | |
574 | struct aa_profile *unconfined = ns->unconfined; | |
575 | ||
576 | /* remove ns from namespace list */ | |
577 | list_del_init(&ns->base.list); | |
578 | ||
579 | /* | |
580 | * break the ns, unconfined profile cyclic reference and forward | |
581 | * all new unconfined profiles requests to the parent namespace | |
582 | * This will result in all confined tasks that have a profile | |
583 | * being removed, inheriting the parent->unconfined profile. | |
584 | */ | |
585 | if (ns->parent) | |
586 | ns->unconfined = aa_get_profile(ns->parent->unconfined); | |
587 | ||
588 | destroy_namespace(ns); | |
589 | ||
590 | /* release original ns->unconfined ref */ | |
591 | aa_put_profile(unconfined); | |
592 | /* release ns->base.list ref, from removal above */ | |
593 | aa_put_namespace(ns); | |
594 | } | |
595 | ||
596 | /** | |
597 | * __ns_list_release - remove all profile namespaces on the list put refs | |
598 | * @head: list of profile namespaces (NOT NULL) | |
599 | * | |
600 | * Requires: namespace lock be held | |
601 | */ | |
602 | static void __ns_list_release(struct list_head *head) | |
603 | { | |
604 | struct aa_namespace *ns, *tmp; | |
605 | list_for_each_entry_safe(ns, tmp, head, base.list) | |
606 | __remove_namespace(ns); | |
607 | ||
608 | } | |
609 | ||
610 | /** | |
611 | * aa_alloc_root_ns - allocate the root profile namespace | |
612 | * | |
613 | * Returns: %0 on success else error | |
614 | * | |
615 | */ | |
616 | int __init aa_alloc_root_ns(void) | |
617 | { | |
618 | /* released by aa_free_root_ns - used as list ref*/ | |
619 | root_ns = alloc_namespace(NULL, "root"); | |
620 | if (!root_ns) | |
621 | return -ENOMEM; | |
622 | ||
623 | return 0; | |
624 | } | |
625 | ||
626 | /** | |
627 | * aa_free_root_ns - free the root profile namespace | |
628 | */ | |
629 | void __init aa_free_root_ns(void) | |
630 | { | |
631 | struct aa_namespace *ns = root_ns; | |
632 | root_ns = NULL; | |
633 | ||
634 | destroy_namespace(ns); | |
635 | aa_put_namespace(ns); | |
636 | } | |
637 | ||
638 | /** | |
639 | * aa_alloc_profile - allocate, initialize and return a new profile | |
640 | * @hname: name of the profile (NOT NULL) | |
641 | * | |
642 | * Returns: refcount profile or NULL on failure | |
643 | */ | |
644 | struct aa_profile *aa_alloc_profile(const char *hname) | |
645 | { | |
646 | struct aa_profile *profile; | |
647 | ||
648 | /* freed by free_profile - usually through aa_put_profile */ | |
649 | profile = kzalloc(sizeof(*profile), GFP_KERNEL); | |
650 | if (!profile) | |
651 | return NULL; | |
652 | ||
653 | if (!policy_init(&profile->base, NULL, hname)) { | |
654 | kzfree(profile); | |
655 | return NULL; | |
656 | } | |
657 | ||
658 | /* refcount released by caller */ | |
659 | return profile; | |
660 | } | |
661 | ||
662 | /** | |
663 | * aa_new_null_profile - create a new null-X learning profile | |
664 | * @parent: profile that caused this profile to be created (NOT NULL) | |
665 | * @hat: true if the null- learning profile is a hat | |
666 | * | |
667 | * Create a null- complain mode profile used in learning mode. The name of | |
668 | * the profile is unique and follows the format of parent//null-sid. | |
669 | * | |
670 | * null profiles are added to the profile list but the list does not | |
671 | * hold a count on them so that they are automatically released when | |
672 | * not in use. | |
673 | * | |
674 | * Returns: new refcounted profile else NULL on failure | |
675 | */ | |
676 | struct aa_profile *aa_new_null_profile(struct aa_profile *parent, int hat) | |
677 | { | |
678 | struct aa_profile *profile = NULL; | |
679 | char *name; | |
680 | u32 sid = aa_alloc_sid(); | |
681 | ||
682 | /* freed below */ | |
683 | name = kmalloc(strlen(parent->base.hname) + 2 + 7 + 8, GFP_KERNEL); | |
684 | if (!name) | |
685 | goto fail; | |
686 | sprintf(name, "%s//null-%x", parent->base.hname, sid); | |
687 | ||
688 | profile = aa_alloc_profile(name); | |
689 | kfree(name); | |
690 | if (!profile) | |
691 | goto fail; | |
692 | ||
693 | profile->sid = sid; | |
694 | profile->mode = APPARMOR_COMPLAIN; | |
695 | profile->flags = PFLAG_NULL; | |
696 | if (hat) | |
697 | profile->flags |= PFLAG_HAT; | |
698 | ||
699 | /* released on free_profile */ | |
700 | profile->parent = aa_get_profile(parent); | |
701 | profile->ns = aa_get_namespace(parent->ns); | |
702 | ||
703 | write_lock(&profile->ns->lock); | |
704 | __list_add_profile(&parent->base.profiles, profile); | |
705 | write_unlock(&profile->ns->lock); | |
706 | ||
707 | /* refcount released by caller */ | |
708 | return profile; | |
709 | ||
710 | fail: | |
711 | aa_free_sid(sid); | |
712 | return NULL; | |
713 | } | |
714 | ||
715 | /** | |
716 | * free_profile - free a profile | |
717 | * @profile: the profile to free (MAYBE NULL) | |
718 | * | |
719 | * Free a profile, its hats and null_profile. All references to the profile, | |
720 | * its hats and null_profile must have been put. | |
721 | * | |
722 | * If the profile was referenced from a task context, free_profile() will | |
723 | * be called from an rcu callback routine, so we must not sleep here. | |
724 | */ | |
725 | static void free_profile(struct aa_profile *profile) | |
726 | { | |
2e680dd6 JJ |
727 | struct aa_profile *p; |
728 | ||
c88d4c7b JJ |
729 | AA_DEBUG("%s(%p)\n", __func__, profile); |
730 | ||
731 | if (!profile) | |
732 | return; | |
733 | ||
734 | if (!list_empty(&profile->base.list)) { | |
735 | AA_ERROR("%s: internal error, " | |
736 | "profile '%s' still on ns list\n", | |
737 | __func__, profile->base.name); | |
738 | BUG(); | |
739 | } | |
740 | ||
741 | /* free children profiles */ | |
742 | policy_destroy(&profile->base); | |
743 | aa_put_profile(profile->parent); | |
744 | ||
745 | aa_put_namespace(profile->ns); | |
746 | kzfree(profile->rename); | |
747 | ||
748 | aa_free_file_rules(&profile->file); | |
749 | aa_free_cap_rules(&profile->caps); | |
750 | aa_free_rlimit_rules(&profile->rlimits); | |
751 | ||
752 | aa_free_sid(profile->sid); | |
753 | aa_put_dfa(profile->xmatch); | |
ad5ff3db | 754 | aa_put_dfa(profile->policy.dfa); |
c88d4c7b | 755 | |
2e680dd6 JJ |
756 | /* put the profile reference for replacedby, but not via |
757 | * put_profile(kref_put). | |
758 | * replacedby can form a long chain that can result in cascading | |
759 | * frees that blows the stack because kref_put makes a nested fn | |
760 | * call (it looks like recursion, with free_profile calling | |
761 | * free_profile) for each profile in the chain lp#1056078. | |
762 | */ | |
763 | for (p = profile->replacedby; p; ) { | |
764 | if (atomic_dec_and_test(&p->base.count.refcount)) { | |
765 | /* no more refs on p, grab its replacedby */ | |
766 | struct aa_profile *next = p->replacedby; | |
767 | /* break the chain */ | |
768 | p->replacedby = NULL; | |
769 | /* now free p, chain is broken */ | |
770 | free_profile(p); | |
771 | ||
772 | /* follow up with next profile in the chain */ | |
773 | p = next; | |
774 | } else | |
775 | break; | |
776 | } | |
c88d4c7b JJ |
777 | |
778 | kzfree(profile); | |
779 | } | |
780 | ||
781 | /** | |
782 | * aa_free_profile_kref - free aa_profile by kref (called by aa_put_profile) | |
783 | * @kr: kref callback for freeing of a profile (NOT NULL) | |
784 | */ | |
785 | void aa_free_profile_kref(struct kref *kref) | |
786 | { | |
787 | struct aa_profile *p = container_of(kref, struct aa_profile, | |
788 | base.count); | |
789 | ||
790 | free_profile(p); | |
791 | } | |
792 | ||
793 | /* TODO: profile accounting - setup in remove */ | |
794 | ||
795 | /** | |
796 | * __find_child - find a profile on @head list with a name matching @name | |
797 | * @head: list to search (NOT NULL) | |
798 | * @name: name of profile (NOT NULL) | |
799 | * | |
800 | * Requires: ns lock protecting list be held | |
801 | * | |
802 | * Returns: unrefcounted profile ptr, or NULL if not found | |
803 | */ | |
804 | static struct aa_profile *__find_child(struct list_head *head, const char *name) | |
805 | { | |
806 | return (struct aa_profile *)__policy_find(head, name); | |
807 | } | |
808 | ||
809 | /** | |
810 | * __strn_find_child - find a profile on @head list using substring of @name | |
811 | * @head: list to search (NOT NULL) | |
812 | * @name: name of profile (NOT NULL) | |
813 | * @len: length of @name substring to match | |
814 | * | |
815 | * Requires: ns lock protecting list be held | |
816 | * | |
817 | * Returns: unrefcounted profile ptr, or NULL if not found | |
818 | */ | |
819 | static struct aa_profile *__strn_find_child(struct list_head *head, | |
820 | const char *name, int len) | |
821 | { | |
822 | return (struct aa_profile *)__policy_strn_find(head, name, len); | |
823 | } | |
824 | ||
825 | /** | |
826 | * aa_find_child - find a profile by @name in @parent | |
827 | * @parent: profile to search (NOT NULL) | |
828 | * @name: profile name to search for (NOT NULL) | |
829 | * | |
830 | * Returns: a refcounted profile or NULL if not found | |
831 | */ | |
832 | struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name) | |
833 | { | |
834 | struct aa_profile *profile; | |
835 | ||
836 | read_lock(&parent->ns->lock); | |
837 | profile = aa_get_profile(__find_child(&parent->base.profiles, name)); | |
838 | read_unlock(&parent->ns->lock); | |
839 | ||
840 | /* refcount released by caller */ | |
841 | return profile; | |
842 | } | |
843 | ||
844 | /** | |
845 | * __lookup_parent - lookup the parent of a profile of name @hname | |
846 | * @ns: namespace to lookup profile in (NOT NULL) | |
847 | * @hname: hierarchical profile name to find parent of (NOT NULL) | |
848 | * | |
849 | * Lookups up the parent of a fully qualified profile name, the profile | |
850 | * that matches hname does not need to exist, in general this | |
851 | * is used to load a new profile. | |
852 | * | |
853 | * Requires: ns->lock be held | |
854 | * | |
855 | * Returns: unrefcounted policy or NULL if not found | |
856 | */ | |
857 | static struct aa_policy *__lookup_parent(struct aa_namespace *ns, | |
858 | const char *hname) | |
859 | { | |
860 | struct aa_policy *policy; | |
861 | struct aa_profile *profile = NULL; | |
862 | char *split; | |
863 | ||
864 | policy = &ns->base; | |
865 | ||
866 | for (split = strstr(hname, "//"); split;) { | |
867 | profile = __strn_find_child(&policy->profiles, hname, | |
868 | split - hname); | |
869 | if (!profile) | |
870 | return NULL; | |
871 | policy = &profile->base; | |
872 | hname = split + 2; | |
873 | split = strstr(hname, "//"); | |
874 | } | |
875 | if (!profile) | |
876 | return &ns->base; | |
877 | return &profile->base; | |
878 | } | |
879 | ||
880 | /** | |
881 | * __lookup_profile - lookup the profile matching @hname | |
882 | * @base: base list to start looking up profile name from (NOT NULL) | |
883 | * @hname: hierarchical profile name (NOT NULL) | |
884 | * | |
885 | * Requires: ns->lock be held | |
886 | * | |
887 | * Returns: unrefcounted profile pointer or NULL if not found | |
888 | * | |
889 | * Do a relative name lookup, recursing through profile tree. | |
890 | */ | |
891 | static struct aa_profile *__lookup_profile(struct aa_policy *base, | |
892 | const char *hname) | |
893 | { | |
894 | struct aa_profile *profile = NULL; | |
895 | char *split; | |
896 | ||
897 | for (split = strstr(hname, "//"); split;) { | |
898 | profile = __strn_find_child(&base->profiles, hname, | |
899 | split - hname); | |
900 | if (!profile) | |
901 | return NULL; | |
902 | ||
903 | base = &profile->base; | |
904 | hname = split + 2; | |
905 | split = strstr(hname, "//"); | |
906 | } | |
907 | ||
908 | profile = __find_child(&base->profiles, hname); | |
909 | ||
910 | return profile; | |
911 | } | |
912 | ||
913 | /** | |
914 | * aa_lookup_profile - find a profile by its full or partial name | |
915 | * @ns: the namespace to start from (NOT NULL) | |
916 | * @hname: name to do lookup on. Does not contain namespace prefix (NOT NULL) | |
917 | * | |
918 | * Returns: refcounted profile or NULL if not found | |
919 | */ | |
920 | struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *hname) | |
921 | { | |
922 | struct aa_profile *profile; | |
923 | ||
924 | read_lock(&ns->lock); | |
925 | profile = aa_get_profile(__lookup_profile(&ns->base, hname)); | |
926 | read_unlock(&ns->lock); | |
927 | ||
bf83208e JJ |
928 | /* the unconfined profile is not in the regular profile list */ |
929 | if (!profile && strcmp(hname, "unconfined") == 0) | |
930 | profile = aa_get_profile(ns->unconfined); | |
931 | ||
c88d4c7b JJ |
932 | /* refcount released by caller */ |
933 | return profile; | |
934 | } | |
935 | ||
936 | /** | |
937 | * replacement_allowed - test to see if replacement is allowed | |
938 | * @profile: profile to test if it can be replaced (MAYBE NULL) | |
939 | * @noreplace: true if replacement shouldn't be allowed but addition is okay | |
940 | * @info: Returns - info about why replacement failed (NOT NULL) | |
941 | * | |
942 | * Returns: %0 if replacement allowed else error code | |
943 | */ | |
944 | static int replacement_allowed(struct aa_profile *profile, int noreplace, | |
945 | const char **info) | |
946 | { | |
947 | if (profile) { | |
948 | if (profile->flags & PFLAG_IMMUTABLE) { | |
949 | *info = "cannot replace immutible profile"; | |
950 | return -EPERM; | |
951 | } else if (noreplace) { | |
952 | *info = "profile already exists"; | |
953 | return -EEXIST; | |
954 | } | |
955 | } | |
956 | return 0; | |
957 | } | |
958 | ||
959 | /** | |
960 | * __add_new_profile - simple wrapper around __list_add_profile | |
961 | * @ns: namespace that profile is being added to (NOT NULL) | |
962 | * @policy: the policy container to add the profile to (NOT NULL) | |
963 | * @profile: profile to add (NOT NULL) | |
964 | * | |
965 | * add a profile to a list and do other required basic allocations | |
966 | */ | |
967 | static void __add_new_profile(struct aa_namespace *ns, struct aa_policy *policy, | |
968 | struct aa_profile *profile) | |
969 | { | |
970 | if (policy != &ns->base) | |
971 | /* released on profile replacement or free_profile */ | |
972 | profile->parent = aa_get_profile((struct aa_profile *) policy); | |
973 | __list_add_profile(&policy->profiles, profile); | |
974 | /* released on free_profile */ | |
975 | profile->sid = aa_alloc_sid(); | |
976 | profile->ns = aa_get_namespace(ns); | |
977 | } | |
978 | ||
979 | /** | |
980 | * aa_audit_policy - Do auditing of policy changes | |
981 | * @op: policy operation being performed | |
982 | * @gfp: memory allocation flags | |
983 | * @name: name of profile being manipulated (NOT NULL) | |
984 | * @info: any extra information to be audited (MAYBE NULL) | |
985 | * @error: error code | |
986 | * | |
987 | * Returns: the error to be returned after audit is done | |
988 | */ | |
989 | static int audit_policy(int op, gfp_t gfp, const char *name, const char *info, | |
990 | int error) | |
991 | { | |
992 | struct common_audit_data sa; | |
3b3b0e4f | 993 | struct apparmor_audit_data aad = {0,}; |
50c205f5 | 994 | sa.type = LSM_AUDIT_DATA_NONE; |
3b3b0e4f EP |
995 | sa.aad = &aad; |
996 | aad.op = op; | |
997 | aad.name = name; | |
998 | aad.info = info; | |
999 | aad.error = error; | |
c88d4c7b JJ |
1000 | |
1001 | return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp, | |
1002 | &sa, NULL); | |
1003 | } | |
1004 | ||
1005 | /** | |
1006 | * aa_may_manage_policy - can the current task manage policy | |
1007 | * @op: the policy manipulation operation being done | |
1008 | * | |
1009 | * Returns: true if the task is allowed to manipulate policy | |
1010 | */ | |
1011 | bool aa_may_manage_policy(int op) | |
1012 | { | |
1013 | /* check if loading policy is locked out */ | |
1014 | if (aa_g_lock_policy) { | |
1015 | audit_policy(op, GFP_KERNEL, NULL, "policy_locked", -EACCES); | |
1016 | return 0; | |
1017 | } | |
1018 | ||
1019 | if (!capable(CAP_MAC_ADMIN)) { | |
1020 | audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES); | |
1021 | return 0; | |
1022 | } | |
1023 | ||
1024 | return 1; | |
1025 | } | |
1026 | ||
1027 | /** | |
1028 | * aa_replace_profiles - replace profile(s) on the profile list | |
1029 | * @udata: serialized data stream (NOT NULL) | |
1030 | * @size: size of the serialized data stream | |
1031 | * @noreplace: true if only doing addition, no replacement allowed | |
1032 | * | |
1033 | * unpack and replace a profile on the profile list and uses of that profile | |
1034 | * by any aa_task_cxt. If the profile does not exist on the profile list | |
1035 | * it is added. | |
1036 | * | |
1037 | * Returns: size of data consumed else error code on failure. | |
1038 | */ | |
1039 | ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace) | |
1040 | { | |
1041 | struct aa_policy *policy; | |
1042 | struct aa_profile *old_profile = NULL, *new_profile = NULL; | |
1043 | struct aa_profile *rename_profile = NULL; | |
1044 | struct aa_namespace *ns = NULL; | |
1045 | const char *ns_name, *name = NULL, *info = NULL; | |
1046 | int op = OP_PROF_REPL; | |
1047 | ssize_t error; | |
1048 | ||
1049 | /* released below */ | |
1050 | new_profile = aa_unpack(udata, size, &ns_name); | |
1051 | if (IS_ERR(new_profile)) { | |
1052 | error = PTR_ERR(new_profile); | |
1053 | new_profile = NULL; | |
1054 | goto fail; | |
1055 | } | |
1056 | ||
1057 | /* released below */ | |
1058 | ns = aa_prepare_namespace(ns_name); | |
1059 | if (!ns) { | |
1060 | info = "failed to prepare namespace"; | |
1061 | error = -ENOMEM; | |
1062 | name = ns_name; | |
1063 | goto fail; | |
1064 | } | |
1065 | ||
1066 | name = new_profile->base.hname; | |
1067 | ||
1068 | write_lock(&ns->lock); | |
1069 | /* no ref on policy only use inside lock */ | |
1070 | policy = __lookup_parent(ns, new_profile->base.hname); | |
1071 | ||
1072 | if (!policy) { | |
1073 | info = "parent does not exist"; | |
1074 | error = -ENOENT; | |
1075 | goto audit; | |
1076 | } | |
1077 | ||
1078 | old_profile = __find_child(&policy->profiles, new_profile->base.name); | |
1079 | /* released below */ | |
1080 | aa_get_profile(old_profile); | |
1081 | ||
1082 | if (new_profile->rename) { | |
1083 | rename_profile = __lookup_profile(&ns->base, | |
1084 | new_profile->rename); | |
1085 | /* released below */ | |
1086 | aa_get_profile(rename_profile); | |
1087 | ||
1088 | if (!rename_profile) { | |
1089 | info = "profile to rename does not exist"; | |
1090 | name = new_profile->rename; | |
1091 | error = -ENOENT; | |
1092 | goto audit; | |
1093 | } | |
1094 | } | |
1095 | ||
1096 | error = replacement_allowed(old_profile, noreplace, &info); | |
1097 | if (error) | |
1098 | goto audit; | |
1099 | ||
1100 | error = replacement_allowed(rename_profile, noreplace, &info); | |
1101 | if (error) | |
1102 | goto audit; | |
1103 | ||
1104 | audit: | |
1105 | if (!old_profile && !rename_profile) | |
1106 | op = OP_PROF_LOAD; | |
1107 | ||
1108 | error = audit_policy(op, GFP_ATOMIC, name, info, error); | |
1109 | ||
1110 | if (!error) { | |
1111 | if (rename_profile) | |
1112 | __replace_profile(rename_profile, new_profile); | |
1113 | if (old_profile) { | |
1114 | /* when there are both rename and old profiles | |
1115 | * inherit old profiles sid | |
1116 | */ | |
1117 | if (rename_profile) | |
1118 | aa_free_sid(new_profile->sid); | |
1119 | __replace_profile(old_profile, new_profile); | |
1120 | } | |
1121 | if (!(old_profile || rename_profile)) | |
1122 | __add_new_profile(ns, policy, new_profile); | |
1123 | } | |
1124 | write_unlock(&ns->lock); | |
1125 | ||
1126 | out: | |
1127 | aa_put_namespace(ns); | |
1128 | aa_put_profile(rename_profile); | |
1129 | aa_put_profile(old_profile); | |
1130 | aa_put_profile(new_profile); | |
1131 | if (error) | |
1132 | return error; | |
1133 | return size; | |
1134 | ||
1135 | fail: | |
1136 | error = audit_policy(op, GFP_KERNEL, name, info, error); | |
1137 | goto out; | |
1138 | } | |
1139 | ||
1140 | /** | |
1141 | * aa_remove_profiles - remove profile(s) from the system | |
1142 | * @fqname: name of the profile or namespace to remove (NOT NULL) | |
1143 | * @size: size of the name | |
1144 | * | |
1145 | * Remove a profile or sub namespace from the current namespace, so that | |
1146 | * they can not be found anymore and mark them as replaced by unconfined | |
1147 | * | |
1148 | * NOTE: removing confinement does not restore rlimits to preconfinemnet values | |
1149 | * | |
1150 | * Returns: size of data consume else error code if fails | |
1151 | */ | |
1152 | ssize_t aa_remove_profiles(char *fqname, size_t size) | |
1153 | { | |
1154 | struct aa_namespace *root, *ns = NULL; | |
1155 | struct aa_profile *profile = NULL; | |
1156 | const char *name = fqname, *info = NULL; | |
1157 | ssize_t error = 0; | |
1158 | ||
1159 | if (*fqname == 0) { | |
1160 | info = "no profile specified"; | |
1161 | error = -ENOENT; | |
1162 | goto fail; | |
1163 | } | |
1164 | ||
1165 | root = aa_current_profile()->ns; | |
1166 | ||
1167 | if (fqname[0] == ':') { | |
1168 | char *ns_name; | |
1169 | name = aa_split_fqname(fqname, &ns_name); | |
1170 | if (ns_name) { | |
1171 | /* released below */ | |
1172 | ns = aa_find_namespace(root, ns_name); | |
1173 | if (!ns) { | |
1174 | info = "namespace does not exist"; | |
1175 | error = -ENOENT; | |
1176 | goto fail; | |
1177 | } | |
1178 | } | |
1179 | } else | |
1180 | /* released below */ | |
1181 | ns = aa_get_namespace(root); | |
1182 | ||
c88d4c7b JJ |
1183 | if (!name) { |
1184 | /* remove namespace - can only happen if fqname[0] == ':' */ | |
999b4f0a | 1185 | write_lock(&ns->parent->lock); |
c88d4c7b | 1186 | __remove_namespace(ns); |
999b4f0a | 1187 | write_unlock(&ns->parent->lock); |
c88d4c7b JJ |
1188 | } else { |
1189 | /* remove profile */ | |
999b4f0a | 1190 | write_lock(&ns->lock); |
c88d4c7b JJ |
1191 | profile = aa_get_profile(__lookup_profile(&ns->base, name)); |
1192 | if (!profile) { | |
1193 | error = -ENOENT; | |
1194 | info = "profile does not exist"; | |
1195 | goto fail_ns_lock; | |
1196 | } | |
1197 | name = profile->base.hname; | |
1198 | __remove_profile(profile); | |
999b4f0a | 1199 | write_unlock(&ns->lock); |
c88d4c7b | 1200 | } |
c88d4c7b JJ |
1201 | |
1202 | /* don't fail removal if audit fails */ | |
1203 | (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error); | |
1204 | aa_put_namespace(ns); | |
1205 | aa_put_profile(profile); | |
1206 | return size; | |
1207 | ||
1208 | fail_ns_lock: | |
1209 | write_unlock(&ns->lock); | |
1210 | aa_put_namespace(ns); | |
1211 | ||
1212 | fail: | |
1213 | (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error); | |
1214 | return error; | |
1215 | } |