Root/security/apparmor/policy.c

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 */
94struct aa_namespace *root_ns;
95
96const 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 */
108static 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 */
128static 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 */
154static 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 */
182static 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 */
206static 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
223static 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 */
231bool 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 */
250const 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 */
275static 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
308fail_unconfined:
309    kzfree(ns->base.name);
310fail_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 */
322static 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 */
341void 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 */
355static 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 */
371struct 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 */
389static 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    }
431out:
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 */
447static 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 */
467static 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 */
487static 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
515static 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 */
523static 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 */
538static 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
545static 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 */
551static 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 */
572static 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 */
602static 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 */
616int __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  */
629void __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 */
644struct 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 */
676struct 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
710fail:
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 */
725static 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 */
762void 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 */
781static 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 */
796static 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 */
809struct 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 */
834static 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 */
868static 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 */
897struct 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 */
917static 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 */
940static 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 */
962static 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 */
982bool 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 */
1010ssize_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
1075audit:
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
1097out:
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
1106fail:
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 */
1123ssize_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
1179fail_ns_lock:
1180    write_unlock(&ns->lock);
1181    aa_put_namespace(ns);
1182
1183fail:
1184    (void) audit_policy(OP_PROF_RM, GFP_KERNEL, name, info, error);
1185    return error;
1186}
1187

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