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Source at commit be977234bfb4a6dca8a39e7c52165e4cd536ad71 created 12 years 9 months ago. By Lars-Peter Clausen, jz4740: Fix compile error | |
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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 | #include "include/sid.h" |
91 | |
92 | |
93 | /* root profile namespace */ |
94 | struct aa_namespace *root_ns; |
95 | |
96 | const char *profile_mode_names[] = { |
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: |
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 | 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 | { |
727 | AA_DEBUG("%s(%p)\n", __func__, profile); |
728 | |
729 | if (!profile) |
730 | return; |
731 | |
732 | if (!list_empty(&profile->base.list)) { |
733 | AA_ERROR("%s: internal error, " |
734 | "profile '%s' still on ns list\n", |
735 | __func__, profile->base.name); |
736 | BUG(); |
737 | } |
738 | |
739 | /* free children profiles */ |
740 | policy_destroy(&profile->base); |
741 | aa_put_profile(profile->parent); |
742 | |
743 | aa_put_namespace(profile->ns); |
744 | kzfree(profile->rename); |
745 | |
746 | aa_free_file_rules(&profile->file); |
747 | aa_free_cap_rules(&profile->caps); |
748 | aa_free_rlimit_rules(&profile->rlimits); |
749 | |
750 | aa_free_sid(profile->sid); |
751 | aa_put_dfa(profile->xmatch); |
752 | |
753 | aa_put_profile(profile->replacedby); |
754 | |
755 | kzfree(profile); |
756 | } |
757 | |
758 | /** |
759 | * aa_free_profile_kref - free aa_profile by kref (called by aa_put_profile) |
760 | * @kr: kref callback for freeing of a profile (NOT NULL) |
761 | */ |
762 | void aa_free_profile_kref(struct kref *kref) |
763 | { |
764 | struct aa_profile *p = container_of(kref, struct aa_profile, |
765 | base.count); |
766 | |
767 | free_profile(p); |
768 | } |
769 | |
770 | /* TODO: profile accounting - setup in remove */ |
771 | |
772 | /** |
773 | * __find_child - find a profile on @head list with a name matching @name |
774 | * @head: list to search (NOT NULL) |
775 | * @name: name of profile (NOT NULL) |
776 | * |
777 | * Requires: ns lock protecting list be held |
778 | * |
779 | * Returns: unrefcounted profile ptr, or NULL if not found |
780 | */ |
781 | static struct aa_profile *__find_child(struct list_head *head, const char *name) |
782 | { |
783 | return (struct aa_profile *)__policy_find(head, name); |
784 | } |
785 | |
786 | /** |
787 | * __strn_find_child - find a profile on @head list using substring of @name |
788 | * @head: list to search (NOT NULL) |
789 | * @name: name of profile (NOT NULL) |
790 | * @len: length of @name substring to match |
791 | * |
792 | * Requires: ns lock protecting list be held |
793 | * |
794 | * Returns: unrefcounted profile ptr, or NULL if not found |
795 | */ |
796 | static struct aa_profile *__strn_find_child(struct list_head *head, |
797 | const char *name, int len) |
798 | { |
799 | return (struct aa_profile *)__policy_strn_find(head, name, len); |
800 | } |
801 | |
802 | /** |
803 | * aa_find_child - find a profile by @name in @parent |
804 | * @parent: profile to search (NOT NULL) |
805 | * @name: profile name to search for (NOT NULL) |
806 | * |
807 | * Returns: a refcounted profile or NULL if not found |
808 | */ |
809 | struct aa_profile *aa_find_child(struct aa_profile *parent, const char *name) |
810 | { |
811 | struct aa_profile *profile; |
812 | |
813 | read_lock(&parent->ns->lock); |
814 | profile = aa_get_profile(__find_child(&parent->base.profiles, name)); |
815 | read_unlock(&parent->ns->lock); |
816 | |
817 | /* refcount released by caller */ |
818 | return profile; |
819 | } |
820 | |
821 | /** |
822 | * __lookup_parent - lookup the parent of a profile of name @hname |
823 | * @ns: namespace to lookup profile in (NOT NULL) |
824 | * @hname: hierarchical profile name to find parent of (NOT NULL) |
825 | * |
826 | * Lookups up the parent of a fully qualified profile name, the profile |
827 | * that matches hname does not need to exist, in general this |
828 | * is used to load a new profile. |
829 | * |
830 | * Requires: ns->lock be held |
831 | * |
832 | * Returns: unrefcounted policy or NULL if not found |
833 | */ |
834 | static struct aa_policy *__lookup_parent(struct aa_namespace *ns, |
835 | const char *hname) |
836 | { |
837 | struct aa_policy *policy; |
838 | struct aa_profile *profile = NULL; |
839 | char *split; |
840 | |
841 | policy = &ns->base; |
842 | |
843 | for (split = strstr(hname, "//"); split;) { |
844 | profile = __strn_find_child(&policy->profiles, hname, |
845 | split - hname); |
846 | if (!profile) |
847 | return NULL; |
848 | policy = &profile->base; |
849 | hname = split + 2; |
850 | split = strstr(hname, "//"); |
851 | } |
852 | if (!profile) |
853 | return &ns->base; |
854 | return &profile->base; |
855 | } |
856 | |
857 | /** |
858 | * __lookup_profile - lookup the profile matching @hname |
859 | * @base: base list to start looking up profile name from (NOT NULL) |
860 | * @hname: hierarchical profile name (NOT NULL) |
861 | * |
862 | * Requires: ns->lock be held |
863 | * |
864 | * Returns: unrefcounted profile pointer or NULL if not found |
865 | * |
866 | * Do a relative name lookup, recursing through profile tree. |
867 | */ |
868 | static struct aa_profile *__lookup_profile(struct aa_policy *base, |
869 | const char *hname) |
870 | { |
871 | struct aa_profile *profile = NULL; |
872 | char *split; |
873 | |
874 | for (split = strstr(hname, "//"); split;) { |
875 | profile = __strn_find_child(&base->profiles, hname, |
876 | split - hname); |
877 | if (!profile) |
878 | return NULL; |
879 | |
880 | base = &profile->base; |
881 | hname = split + 2; |
882 | split = strstr(hname, "//"); |
883 | } |
884 | |
885 | profile = __find_child(&base->profiles, hname); |
886 | |
887 | return profile; |
888 | } |
889 | |
890 | /** |
891 | * aa_lookup_profile - find a profile by its full or partial name |
892 | * @ns: the namespace to start from (NOT NULL) |
893 | * @hname: name to do lookup on. Does not contain namespace prefix (NOT NULL) |
894 | * |
895 | * Returns: refcounted profile or NULL if not found |
896 | */ |
897 | struct aa_profile *aa_lookup_profile(struct aa_namespace *ns, const char *hname) |
898 | { |
899 | struct aa_profile *profile; |
900 | |
901 | read_lock(&ns->lock); |
902 | profile = aa_get_profile(__lookup_profile(&ns->base, hname)); |
903 | read_unlock(&ns->lock); |
904 | |
905 | /* refcount released by caller */ |
906 | return profile; |
907 | } |
908 | |
909 | /** |
910 | * replacement_allowed - test to see if replacement is allowed |
911 | * @profile: profile to test if it can be replaced (MAYBE NULL) |
912 | * @noreplace: true if replacement shouldn't be allowed but addition is okay |
913 | * @info: Returns - info about why replacement failed (NOT NULL) |
914 | * |
915 | * Returns: %0 if replacement allowed else error code |
916 | */ |
917 | static int replacement_allowed(struct aa_profile *profile, int noreplace, |
918 | const char **info) |
919 | { |
920 | if (profile) { |
921 | if (profile->flags & PFLAG_IMMUTABLE) { |
922 | *info = "cannot replace immutible profile"; |
923 | return -EPERM; |
924 | } else if (noreplace) { |
925 | *info = "profile already exists"; |
926 | return -EEXIST; |
927 | } |
928 | } |
929 | return 0; |
930 | } |
931 | |
932 | /** |
933 | * __add_new_profile - simple wrapper around __list_add_profile |
934 | * @ns: namespace that profile is being added to (NOT NULL) |
935 | * @policy: the policy container to add the profile to (NOT NULL) |
936 | * @profile: profile to add (NOT NULL) |
937 | * |
938 | * add a profile to a list and do other required basic allocations |
939 | */ |
940 | static void __add_new_profile(struct aa_namespace *ns, struct aa_policy *policy, |
941 | struct aa_profile *profile) |
942 | { |
943 | if (policy != &ns->base) |
944 | /* released on profile replacement or free_profile */ |
945 | profile->parent = aa_get_profile((struct aa_profile *) policy); |
946 | __list_add_profile(&policy->profiles, profile); |
947 | /* released on free_profile */ |
948 | profile->sid = aa_alloc_sid(); |
949 | profile->ns = aa_get_namespace(ns); |
950 | } |
951 | |
952 | /** |
953 | * aa_audit_policy - Do auditing of policy changes |
954 | * @op: policy operation being performed |
955 | * @gfp: memory allocation flags |
956 | * @name: name of profile being manipulated (NOT NULL) |
957 | * @info: any extra information to be audited (MAYBE NULL) |
958 | * @error: error code |
959 | * |
960 | * Returns: the error to be returned after audit is done |
961 | */ |
962 | static int audit_policy(int op, gfp_t gfp, const char *name, const char *info, |
963 | int error) |
964 | { |
965 | struct common_audit_data sa; |
966 | COMMON_AUDIT_DATA_INIT(&sa, NONE); |
967 | sa.aad.op = op; |
968 | sa.aad.name = name; |
969 | sa.aad.info = info; |
970 | sa.aad.error = error; |
971 | |
972 | return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp, |
973 | &sa, NULL); |
974 | } |
975 | |
976 | /** |
977 | * aa_may_manage_policy - can the current task manage policy |
978 | * @op: the policy manipulation operation being done |
979 | * |
980 | * Returns: true if the task is allowed to manipulate policy |
981 | */ |
982 | bool aa_may_manage_policy(int op) |
983 | { |
984 | /* check if loading policy is locked out */ |
985 | if (aa_g_lock_policy) { |
986 | audit_policy(op, GFP_KERNEL, NULL, "policy_locked", -EACCES); |
987 | return 0; |
988 | } |
989 | |
990 | if (!capable(CAP_MAC_ADMIN)) { |
991 | audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES); |
992 | return 0; |
993 | } |
994 | |
995 | return 1; |
996 | } |
997 | |
998 | /** |
999 | * aa_replace_profiles - replace profile(s) on the profile list |
1000 | * @udata: serialized data stream (NOT NULL) |
1001 | * @size: size of the serialized data stream |
1002 | * @noreplace: true if only doing addition, no replacement allowed |
1003 | * |
1004 | * unpack and replace a profile on the profile list and uses of that profile |
1005 | * by any aa_task_cxt. If the profile does not exist on the profile list |
1006 | * it is added. |
1007 | * |
1008 | * Returns: size of data consumed else error code on failure. |
1009 | */ |
1010 | ssize_t aa_replace_profiles(void *udata, size_t size, bool noreplace) |
1011 | { |
1012 | struct aa_policy *policy; |
1013 | struct aa_profile *old_profile = NULL, *new_profile = NULL; |
1014 | struct aa_profile *rename_profile = NULL; |
1015 | struct aa_namespace *ns = NULL; |
1016 | const char *ns_name, *name = NULL, *info = NULL; |
1017 | int op = OP_PROF_REPL; |
1018 | ssize_t error; |
1019 | |
1020 | /* released below */ |
1021 | new_profile = aa_unpack(udata, size, &ns_name); |
1022 | if (IS_ERR(new_profile)) { |
1023 | error = PTR_ERR(new_profile); |
1024 | new_profile = NULL; |
1025 | goto fail; |
1026 | } |
1027 | |
1028 | /* released below */ |
1029 | ns = aa_prepare_namespace(ns_name); |
1030 | if (!ns) { |
1031 | info = "failed to prepare namespace"; |
1032 | error = -ENOMEM; |
1033 | name = ns_name; |
1034 | goto fail; |
1035 | } |
1036 | |
1037 | name = new_profile->base.hname; |
1038 | |
1039 | write_lock(&ns->lock); |
1040 | /* no ref on policy only use inside lock */ |
1041 | policy = __lookup_parent(ns, new_profile->base.hname); |
1042 | |
1043 | if (!policy) { |
1044 | info = "parent does not exist"; |
1045 | error = -ENOENT; |
1046 | goto audit; |
1047 | } |
1048 | |
1049 | old_profile = __find_child(&policy->profiles, new_profile->base.name); |
1050 | /* released below */ |
1051 | aa_get_profile(old_profile); |
1052 | |
1053 | if (new_profile->rename) { |
1054 | rename_profile = __lookup_profile(&ns->base, |
1055 | new_profile->rename); |
1056 | /* released below */ |
1057 | aa_get_profile(rename_profile); |
1058 | |
1059 | if (!rename_profile) { |
1060 | info = "profile to rename does not exist"; |
1061 | name = new_profile->rename; |
1062 | error = -ENOENT; |
1063 | goto audit; |
1064 | } |
1065 | } |
1066 | |
1067 | error = replacement_allowed(old_profile, noreplace, &info); |
1068 | if (error) |
1069 | goto audit; |
1070 | |
1071 | error = replacement_allowed(rename_profile, noreplace, &info); |
1072 | if (error) |
1073 | goto audit; |
1074 | |
1075 | audit: |
1076 | if (!old_profile && !rename_profile) |
1077 | op = OP_PROF_LOAD; |
1078 | |
1079 | error = audit_policy(op, GFP_ATOMIC, name, info, error); |
1080 | |
1081 | if (!error) { |
1082 | if (rename_profile) |
1083 | __replace_profile(rename_profile, new_profile); |
1084 | if (old_profile) { |
1085 | /* when there are both rename and old profiles |
1086 | * inherit old profiles sid |
1087 | */ |
1088 | if (rename_profile) |
1089 | aa_free_sid(new_profile->sid); |
1090 | __replace_profile(old_profile, new_profile); |
1091 | } |
1092 | if (!(old_profile || rename_profile)) |
1093 | __add_new_profile(ns, policy, new_profile); |
1094 | } |
1095 | write_unlock(&ns->lock); |
1096 | |
1097 | out: |
1098 | aa_put_namespace(ns); |
1099 | aa_put_profile(rename_profile); |
1100 | aa_put_profile(old_profile); |
1101 | aa_put_profile(new_profile); |
1102 | if (error) |
1103 | return error; |
1104 | return size; |
1105 | |
1106 | fail: |
1107 | error = audit_policy(op, GFP_KERNEL, name, info, error); |
1108 | goto out; |
1109 | } |
1110 | |
1111 | /** |
1112 | * aa_remove_profiles - remove profile(s) from the system |
1113 | * @fqname: name of the profile or namespace to remove (NOT NULL) |
1114 | * @size: size of the name |
1115 | * |
1116 | * Remove a profile or sub namespace from the current namespace, so that |
1117 | * they can not be found anymore and mark them as replaced by unconfined |
1118 | * |
1119 | * NOTE: removing confinement does not restore rlimits to preconfinemnet values |
1120 | * |
1121 | * Returns: size of data consume else error code if fails |
1122 | */ |
1123 | ssize_t aa_remove_profiles(char *fqname, size_t size) |
1124 | { |
1125 | struct aa_namespace *root, *ns = NULL; |
1126 | struct aa_profile *profile = NULL; |
1127 | const char *name = fqname, *info = NULL; |
1128 | ssize_t error = 0; |
1129 | |
1130 | if (*fqname == 0) { |
1131 | info = "no profile specified"; |
1132 | error = -ENOENT; |
1133 | goto fail; |
1134 | } |
1135 | |
1136 | root = aa_current_profile()->ns; |
1137 | |
1138 | if (fqname[0] == ':') { |
1139 | char *ns_name; |
1140 | name = aa_split_fqname(fqname, &ns_name); |
1141 | if (ns_name) { |
1142 | /* released below */ |
1143 | ns = aa_find_namespace(root, ns_name); |
1144 | if (!ns) { |
1145 | info = "namespace does not exist"; |
1146 | error = -ENOENT; |
1147 | goto fail; |
1148 | } |
1149 | } |
1150 | } else |
1151 | /* released below */ |
1152 | ns = aa_get_namespace(root); |
1153 | |
1154 | if (!name) { |
1155 | /* remove namespace - can only happen if fqname[0] == ':' */ |
1156 | write_lock(&ns->parent->lock); |
1157 | __remove_namespace(ns); |
1158 | write_unlock(&ns->parent->lock); |
1159 | } else { |
1160 | /* remove profile */ |
1161 | write_lock(&ns->lock); |
1162 | profile = aa_get_profile(__lookup_profile(&ns->base, name)); |
1163 | if (!profile) { |
1164 | error = -ENOENT; |
1165 | info = "profile does not exist"; |
1166 | goto fail_ns_lock; |
1167 | } |
1168 | name = profile->base.hname; |
1169 | __remove_profile(profile); |
1170 | write_unlock(&ns->lock); |
1171 | } |
1172 | |
1173 | /* don't fail removal if audit fails */ |
1174 | (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error); |
1175 | aa_put_namespace(ns); |
1176 | aa_put_profile(profile); |
1177 | return size; |
1178 | |
1179 | fail_ns_lock: |
1180 | write_unlock(&ns->lock); |
1181 | aa_put_namespace(ns); |
1182 | |
1183 | fail: |
1184 | (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error); |
1185 | return error; |
1186 | } |
1187 |
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