memcg: always create memsw files if CONFIG_CGROUP_MEM_RES_CTLR_SWAP
[linux-2.6.git] / security / apparmor / domain.c
blob6327685c101e49cc720553c9db9f02da3fed1d24
1 /*
2 * AppArmor security module
4 * This file contains AppArmor policy attachment and domain transitions
6 * Copyright (C) 2002-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
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.
15 #include <linux/errno.h>
16 #include <linux/fdtable.h>
17 #include <linux/file.h>
18 #include <linux/mount.h>
19 #include <linux/syscalls.h>
20 #include <linux/tracehook.h>
21 #include <linux/personality.h>
23 #include "include/audit.h"
24 #include "include/apparmorfs.h"
25 #include "include/context.h"
26 #include "include/domain.h"
27 #include "include/file.h"
28 #include "include/ipc.h"
29 #include "include/match.h"
30 #include "include/path.h"
31 #include "include/policy.h"
33 /**
34 * aa_free_domain_entries - free entries in a domain table
35 * @domain: the domain table to free (MAYBE NULL)
37 void aa_free_domain_entries(struct aa_domain *domain)
39 int i;
40 if (domain) {
41 if (!domain->table)
42 return;
44 for (i = 0; i < domain->size; i++)
45 kzfree(domain->table[i]);
46 kzfree(domain->table);
47 domain->table = NULL;
51 /**
52 * may_change_ptraced_domain - check if can change profile on ptraced task
53 * @task: task we want to change profile of (NOT NULL)
54 * @to_profile: profile to change to (NOT NULL)
56 * Check if the task is ptraced and if so if the tracing task is allowed
57 * to trace the new domain
59 * Returns: %0 or error if change not allowed
61 static int may_change_ptraced_domain(struct task_struct *task,
62 struct aa_profile *to_profile)
64 struct task_struct *tracer;
65 const struct cred *cred = NULL;
66 struct aa_profile *tracerp = NULL;
67 int error = 0;
69 rcu_read_lock();
70 tracer = ptrace_parent(task);
71 if (tracer) {
72 /* released below */
73 cred = get_task_cred(tracer);
74 tracerp = aa_cred_profile(cred);
77 /* not ptraced */
78 if (!tracer || unconfined(tracerp))
79 goto out;
81 error = aa_may_ptrace(tracer, tracerp, to_profile, PTRACE_MODE_ATTACH);
83 out:
84 rcu_read_unlock();
85 if (cred)
86 put_cred(cred);
88 return error;
91 /**
92 * change_profile_perms - find permissions for change_profile
93 * @profile: the current profile (NOT NULL)
94 * @ns: the namespace being switched to (NOT NULL)
95 * @name: the name of the profile to change to (NOT NULL)
96 * @request: requested perms
97 * @start: state to start matching in
99 * Returns: permission set
101 static struct file_perms change_profile_perms(struct aa_profile *profile,
102 struct aa_namespace *ns,
103 const char *name, u32 request,
104 unsigned int start)
106 struct file_perms perms;
107 struct path_cond cond = { };
108 unsigned int state;
110 if (unconfined(profile)) {
111 perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
112 perms.audit = perms.quiet = perms.kill = 0;
113 return perms;
114 } else if (!profile->file.dfa) {
115 return nullperms;
116 } else if ((ns == profile->ns)) {
117 /* try matching against rules with out namespace prepended */
118 aa_str_perms(profile->file.dfa, start, name, &cond, &perms);
119 if (COMBINED_PERM_MASK(perms) & request)
120 return perms;
123 /* try matching with namespace name and then profile */
124 state = aa_dfa_match(profile->file.dfa, start, ns->base.name);
125 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
126 aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
128 return perms;
132 * __attach_match_ - find an attachment match
133 * @name - to match against (NOT NULL)
134 * @head - profile list to walk (NOT NULL)
136 * Do a linear search on the profiles in the list. There is a matching
137 * preference where an exact match is preferred over a name which uses
138 * expressions to match, and matching expressions with the greatest
139 * xmatch_len are preferred.
141 * Requires: @head not be shared or have appropriate locks held
143 * Returns: profile or NULL if no match found
145 static struct aa_profile *__attach_match(const char *name,
146 struct list_head *head)
148 int len = 0;
149 struct aa_profile *profile, *candidate = NULL;
151 list_for_each_entry(profile, head, base.list) {
152 if (profile->flags & PFLAG_NULL)
153 continue;
154 if (profile->xmatch && profile->xmatch_len > len) {
155 unsigned int state = aa_dfa_match(profile->xmatch,
156 DFA_START, name);
157 u32 perm = dfa_user_allow(profile->xmatch, state);
158 /* any accepting state means a valid match. */
159 if (perm & MAY_EXEC) {
160 candidate = profile;
161 len = profile->xmatch_len;
163 } else if (!strcmp(profile->base.name, name))
164 /* exact non-re match, no more searching required */
165 return profile;
168 return candidate;
172 * find_attach - do attachment search for unconfined processes
173 * @ns: the current namespace (NOT NULL)
174 * @list: list to search (NOT NULL)
175 * @name: the executable name to match against (NOT NULL)
177 * Returns: profile or NULL if no match found
179 static struct aa_profile *find_attach(struct aa_namespace *ns,
180 struct list_head *list, const char *name)
182 struct aa_profile *profile;
184 read_lock(&ns->lock);
185 profile = aa_get_profile(__attach_match(name, list));
186 read_unlock(&ns->lock);
188 return profile;
192 * separate_fqname - separate the namespace and profile names
193 * @fqname: the fqname name to split (NOT NULL)
194 * @ns_name: the namespace name if it exists (NOT NULL)
196 * This is the xtable equivalent routine of aa_split_fqname. It finds the
197 * split in an xtable fqname which contains an embedded \0 instead of a :
198 * if a namespace is specified. This is done so the xtable is constant and
199 * isn't re-split on every lookup.
201 * Either the profile or namespace name may be optional but if the namespace
202 * is specified the profile name termination must be present. This results
203 * in the following possible encodings:
204 * profile_name\0
205 * :ns_name\0profile_name\0
206 * :ns_name\0\0
208 * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table
210 * Returns: profile name if it is specified else NULL
212 static const char *separate_fqname(const char *fqname, const char **ns_name)
214 const char *name;
216 if (fqname[0] == ':') {
217 /* In this case there is guaranteed to be two \0 terminators
218 * in the string. They are verified at load time by
219 * by unpack_trans_table
221 *ns_name = fqname + 1; /* skip : */
222 name = *ns_name + strlen(*ns_name) + 1;
223 if (!*name)
224 name = NULL;
225 } else {
226 *ns_name = NULL;
227 name = fqname;
230 return name;
233 static const char *next_name(int xtype, const char *name)
235 return NULL;
239 * x_table_lookup - lookup an x transition name via transition table
240 * @profile: current profile (NOT NULL)
241 * @xindex: index into x transition table
243 * Returns: refcounted profile, or NULL on failure (MAYBE NULL)
245 static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex)
247 struct aa_profile *new_profile = NULL;
248 struct aa_namespace *ns = profile->ns;
249 u32 xtype = xindex & AA_X_TYPE_MASK;
250 int index = xindex & AA_X_INDEX_MASK;
251 const char *name;
253 /* index is guaranteed to be in range, validated at load time */
254 for (name = profile->file.trans.table[index]; !new_profile && name;
255 name = next_name(xtype, name)) {
256 struct aa_namespace *new_ns;
257 const char *xname = NULL;
259 new_ns = NULL;
260 if (xindex & AA_X_CHILD) {
261 /* release by caller */
262 new_profile = aa_find_child(profile, name);
263 continue;
264 } else if (*name == ':') {
265 /* switching namespace */
266 const char *ns_name;
267 xname = name = separate_fqname(name, &ns_name);
268 if (!xname)
269 /* no name so use profile name */
270 xname = profile->base.hname;
271 if (*ns_name == '@') {
272 /* TODO: variable support */
275 /* released below */
276 new_ns = aa_find_namespace(ns, ns_name);
277 if (!new_ns)
278 continue;
279 } else if (*name == '@') {
280 /* TODO: variable support */
281 continue;
282 } else {
283 /* basic namespace lookup */
284 xname = name;
287 /* released by caller */
288 new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname);
289 aa_put_namespace(new_ns);
292 /* released by caller */
293 return new_profile;
297 * x_to_profile - get target profile for a given xindex
298 * @profile: current profile (NOT NULL)
299 * @name: name to lookup (NOT NULL)
300 * @xindex: index into x transition table
302 * find profile for a transition index
304 * Returns: refcounted profile or NULL if not found available
306 static struct aa_profile *x_to_profile(struct aa_profile *profile,
307 const char *name, u32 xindex)
309 struct aa_profile *new_profile = NULL;
310 struct aa_namespace *ns = profile->ns;
311 u32 xtype = xindex & AA_X_TYPE_MASK;
313 switch (xtype) {
314 case AA_X_NONE:
315 /* fail exec unless ix || ux fallback - handled by caller */
316 return NULL;
317 case AA_X_NAME:
318 if (xindex & AA_X_CHILD)
319 /* released by caller */
320 new_profile = find_attach(ns, &profile->base.profiles,
321 name);
322 else
323 /* released by caller */
324 new_profile = find_attach(ns, &ns->base.profiles,
325 name);
326 break;
327 case AA_X_TABLE:
328 /* released by caller */
329 new_profile = x_table_lookup(profile, xindex);
330 break;
333 /* released by caller */
334 return new_profile;
338 * apparmor_bprm_set_creds - set the new creds on the bprm struct
339 * @bprm: binprm for the exec (NOT NULL)
341 * Returns: %0 or error on failure
343 int apparmor_bprm_set_creds(struct linux_binprm *bprm)
345 struct aa_task_cxt *cxt;
346 struct aa_profile *profile, *new_profile = NULL;
347 struct aa_namespace *ns;
348 char *buffer = NULL;
349 unsigned int state;
350 struct file_perms perms = {};
351 struct path_cond cond = {
352 bprm->file->f_path.dentry->d_inode->i_uid,
353 bprm->file->f_path.dentry->d_inode->i_mode
355 const char *name = NULL, *target = NULL, *info = NULL;
356 int error = cap_bprm_set_creds(bprm);
357 if (error)
358 return error;
360 if (bprm->cred_prepared)
361 return 0;
363 cxt = bprm->cred->security;
364 BUG_ON(!cxt);
366 profile = aa_get_profile(aa_newest_version(cxt->profile));
368 * get the namespace from the replacement profile as replacement
369 * can change the namespace
371 ns = profile->ns;
372 state = profile->file.start;
374 /* buffer freed below, name is pointer into buffer */
375 error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer,
376 &name, &info);
377 if (error) {
378 if (profile->flags &
379 (PFLAG_IX_ON_NAME_ERROR | PFLAG_UNCONFINED))
380 error = 0;
381 name = bprm->filename;
382 goto audit;
385 /* Test for onexec first as onexec directives override other
386 * x transitions.
388 if (unconfined(profile)) {
389 /* unconfined task */
390 if (cxt->onexec)
391 /* change_profile on exec already been granted */
392 new_profile = aa_get_profile(cxt->onexec);
393 else
394 new_profile = find_attach(ns, &ns->base.profiles, name);
395 if (!new_profile)
396 goto cleanup;
397 goto apply;
400 /* find exec permissions for name */
401 state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
402 if (cxt->onexec) {
403 struct file_perms cp;
404 info = "change_profile onexec";
405 if (!(perms.allow & AA_MAY_ONEXEC))
406 goto audit;
408 /* test if this exec can be paired with change_profile onexec.
409 * onexec permission is linked to exec with a standard pairing
410 * exec\0change_profile
412 state = aa_dfa_null_transition(profile->file.dfa, state);
413 cp = change_profile_perms(profile, cxt->onexec->ns,
414 cxt->onexec->base.name,
415 AA_MAY_ONEXEC, state);
417 if (!(cp.allow & AA_MAY_ONEXEC))
418 goto audit;
419 new_profile = aa_get_profile(aa_newest_version(cxt->onexec));
420 goto apply;
423 if (perms.allow & MAY_EXEC) {
424 /* exec permission determine how to transition */
425 new_profile = x_to_profile(profile, name, perms.xindex);
426 if (!new_profile) {
427 if (perms.xindex & AA_X_INHERIT) {
428 /* (p|c|n)ix - don't change profile but do
429 * use the newest version, which was picked
430 * up above when getting profile
432 info = "ix fallback";
433 new_profile = aa_get_profile(profile);
434 goto x_clear;
435 } else if (perms.xindex & AA_X_UNCONFINED) {
436 new_profile = aa_get_profile(ns->unconfined);
437 info = "ux fallback";
438 } else {
439 error = -ENOENT;
440 info = "profile not found";
443 } else if (COMPLAIN_MODE(profile)) {
444 /* no exec permission - are we in learning mode */
445 new_profile = aa_new_null_profile(profile, 0);
446 if (!new_profile) {
447 error = -ENOMEM;
448 info = "could not create null profile";
449 } else {
450 error = -EACCES;
451 target = new_profile->base.hname;
453 perms.xindex |= AA_X_UNSAFE;
454 } else
455 /* fail exec */
456 error = -EACCES;
458 if (!new_profile)
459 goto audit;
461 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
462 /* FIXME: currently don't mediate shared state */
466 if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
467 error = may_change_ptraced_domain(current, new_profile);
468 if (error) {
469 aa_put_profile(new_profile);
470 goto audit;
474 /* Determine if secure exec is needed.
475 * Can be at this point for the following reasons:
476 * 1. unconfined switching to confined
477 * 2. confined switching to different confinement
478 * 3. confined switching to unconfined
480 * Cases 2 and 3 are marked as requiring secure exec
481 * (unless policy specified "unsafe exec")
483 * bprm->unsafe is used to cache the AA_X_UNSAFE permission
484 * to avoid having to recompute in secureexec
486 if (!(perms.xindex & AA_X_UNSAFE)) {
487 AA_DEBUG("scrubbing environment variables for %s profile=%s\n",
488 name, new_profile->base.hname);
489 bprm->unsafe |= AA_SECURE_X_NEEDED;
491 apply:
492 target = new_profile->base.hname;
493 /* when transitioning profiles clear unsafe personality bits */
494 bprm->per_clear |= PER_CLEAR_ON_SETID;
496 x_clear:
497 aa_put_profile(cxt->profile);
498 /* transfer new profile reference will be released when cxt is freed */
499 cxt->profile = new_profile;
501 /* clear out all temporary/transitional state from the context */
502 aa_put_profile(cxt->previous);
503 aa_put_profile(cxt->onexec);
504 cxt->previous = NULL;
505 cxt->onexec = NULL;
506 cxt->token = 0;
508 audit:
509 error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC,
510 name, target, cond.uid, info, error);
512 cleanup:
513 aa_put_profile(profile);
514 kfree(buffer);
516 return error;
520 * apparmor_bprm_secureexec - determine if secureexec is needed
521 * @bprm: binprm for exec (NOT NULL)
523 * Returns: %1 if secureexec is needed else %0
525 int apparmor_bprm_secureexec(struct linux_binprm *bprm)
527 int ret = cap_bprm_secureexec(bprm);
529 /* the decision to use secure exec is computed in set_creds
530 * and stored in bprm->unsafe.
532 if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED))
533 ret = 1;
535 return ret;
539 * apparmor_bprm_committing_creds - do task cleanup on committing new creds
540 * @bprm: binprm for the exec (NOT NULL)
542 void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
544 struct aa_profile *profile = __aa_current_profile();
545 struct aa_task_cxt *new_cxt = bprm->cred->security;
547 /* bail out if unconfined or not changing profile */
548 if ((new_cxt->profile == profile) ||
549 (unconfined(new_cxt->profile)))
550 return;
552 current->pdeath_signal = 0;
554 /* reset soft limits and set hard limits for the new profile */
555 __aa_transition_rlimits(profile, new_cxt->profile);
559 * apparmor_bprm_commited_cred - do cleanup after new creds committed
560 * @bprm: binprm for the exec (NOT NULL)
562 void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
564 /* TODO: cleanup signals - ipc mediation */
565 return;
569 * Functions for self directed profile change
573 * new_compound_name - create an hname with @n2 appended to @n1
574 * @n1: base of hname (NOT NULL)
575 * @n2: name to append (NOT NULL)
577 * Returns: new name or NULL on error
579 static char *new_compound_name(const char *n1, const char *n2)
581 char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL);
582 if (name)
583 sprintf(name, "%s//%s", n1, n2);
584 return name;
588 * aa_change_hat - change hat to/from subprofile
589 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
590 * @count: number of hat names in @hats
591 * @token: magic value to validate the hat change
592 * @permtest: true if this is just a permission test
594 * Change to the first profile specified in @hats that exists, and store
595 * the @hat_magic in the current task context. If the count == 0 and the
596 * @token matches that stored in the current task context, return to the
597 * top level profile.
599 * Returns %0 on success, error otherwise.
601 int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
603 const struct cred *cred;
604 struct aa_task_cxt *cxt;
605 struct aa_profile *profile, *previous_profile, *hat = NULL;
606 char *name = NULL;
607 int i;
608 struct file_perms perms = {};
609 const char *target = NULL, *info = NULL;
610 int error = 0;
612 /* released below */
613 cred = get_current_cred();
614 cxt = cred->security;
615 profile = aa_cred_profile(cred);
616 previous_profile = cxt->previous;
618 if (unconfined(profile)) {
619 info = "unconfined";
620 error = -EPERM;
621 goto audit;
624 if (count) {
625 /* attempting to change into a new hat or switch to a sibling */
626 struct aa_profile *root;
627 root = PROFILE_IS_HAT(profile) ? profile->parent : profile;
629 /* find first matching hat */
630 for (i = 0; i < count && !hat; i++)
631 /* released below */
632 hat = aa_find_child(root, hats[i]);
633 if (!hat) {
634 if (!COMPLAIN_MODE(root) || permtest) {
635 if (list_empty(&root->base.profiles))
636 error = -ECHILD;
637 else
638 error = -ENOENT;
639 goto out;
643 * In complain mode and failed to match any hats.
644 * Audit the failure is based off of the first hat
645 * supplied. This is done due how userspace
646 * interacts with change_hat.
648 * TODO: Add logging of all failed hats
651 /* freed below */
652 name = new_compound_name(root->base.hname, hats[0]);
653 target = name;
654 /* released below */
655 hat = aa_new_null_profile(profile, 1);
656 if (!hat) {
657 info = "failed null profile create";
658 error = -ENOMEM;
659 goto audit;
661 } else {
662 target = hat->base.hname;
663 if (!PROFILE_IS_HAT(hat)) {
664 info = "target not hat";
665 error = -EPERM;
666 goto audit;
670 error = may_change_ptraced_domain(current, hat);
671 if (error) {
672 info = "ptraced";
673 error = -EPERM;
674 goto audit;
677 if (!permtest) {
678 error = aa_set_current_hat(hat, token);
679 if (error == -EACCES)
680 /* kill task in case of brute force attacks */
681 perms.kill = AA_MAY_CHANGEHAT;
682 else if (name && !error)
683 /* reset error for learning of new hats */
684 error = -ENOENT;
686 } else if (previous_profile) {
687 /* Return to saved profile. Kill task if restore fails
688 * to avoid brute force attacks
690 target = previous_profile->base.hname;
691 error = aa_restore_previous_profile(token);
692 perms.kill = AA_MAY_CHANGEHAT;
693 } else
694 /* ignore restores when there is no saved profile */
695 goto out;
697 audit:
698 if (!permtest)
699 error = aa_audit_file(profile, &perms, GFP_KERNEL,
700 OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL,
701 target, 0, info, error);
703 out:
704 aa_put_profile(hat);
705 kfree(name);
706 put_cred(cred);
708 return error;
712 * aa_change_profile - perform a one-way profile transition
713 * @ns_name: name of the profile namespace to change to (MAYBE NULL)
714 * @hname: name of profile to change to (MAYBE NULL)
715 * @onexec: whether this transition is to take place immediately or at exec
716 * @permtest: true if this is just a permission test
718 * Change to new profile @name. Unlike with hats, there is no way
719 * to change back. If @name isn't specified the current profile name is
720 * used.
721 * If @onexec then the transition is delayed until
722 * the next exec.
724 * Returns %0 on success, error otherwise.
726 int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
727 bool permtest)
729 const struct cred *cred;
730 struct aa_task_cxt *cxt;
731 struct aa_profile *profile, *target = NULL;
732 struct aa_namespace *ns = NULL;
733 struct file_perms perms = {};
734 const char *name = NULL, *info = NULL;
735 int op, error = 0;
736 u32 request;
738 if (!hname && !ns_name)
739 return -EINVAL;
741 if (onexec) {
742 request = AA_MAY_ONEXEC;
743 op = OP_CHANGE_ONEXEC;
744 } else {
745 request = AA_MAY_CHANGE_PROFILE;
746 op = OP_CHANGE_PROFILE;
749 cred = get_current_cred();
750 cxt = cred->security;
751 profile = aa_cred_profile(cred);
753 if (ns_name) {
754 /* released below */
755 ns = aa_find_namespace(profile->ns, ns_name);
756 if (!ns) {
757 /* we don't create new namespace in complain mode */
758 name = ns_name;
759 info = "namespace not found";
760 error = -ENOENT;
761 goto audit;
763 } else
764 /* released below */
765 ns = aa_get_namespace(profile->ns);
767 /* if the name was not specified, use the name of the current profile */
768 if (!hname) {
769 if (unconfined(profile))
770 hname = ns->unconfined->base.hname;
771 else
772 hname = profile->base.hname;
775 perms = change_profile_perms(profile, ns, hname, request,
776 profile->file.start);
777 if (!(perms.allow & request)) {
778 error = -EACCES;
779 goto audit;
782 /* released below */
783 target = aa_lookup_profile(ns, hname);
784 if (!target) {
785 info = "profile not found";
786 error = -ENOENT;
787 if (permtest || !COMPLAIN_MODE(profile))
788 goto audit;
789 /* released below */
790 target = aa_new_null_profile(profile, 0);
791 if (!target) {
792 info = "failed null profile create";
793 error = -ENOMEM;
794 goto audit;
798 /* check if tracing task is allowed to trace target domain */
799 error = may_change_ptraced_domain(current, target);
800 if (error) {
801 info = "ptrace prevents transition";
802 goto audit;
805 if (permtest)
806 goto audit;
808 if (onexec)
809 error = aa_set_current_onexec(target);
810 else
811 error = aa_replace_current_profile(target);
813 audit:
814 if (!permtest)
815 error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request,
816 name, hname, 0, info, error);
818 aa_put_namespace(ns);
819 aa_put_profile(target);
820 put_cred(cred);
822 return error;