blob: 60f0c76a27d3cec1afe576104ef831fe577c54e1 [file] [log] [blame]
John Johansen898127c2010-07-29 14:48:06 -07001/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor policy attachment and domain transitions
5 *
6 * Copyright (C) 2002-2008 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#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>
22
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"
32
33/**
34 * aa_free_domain_entries - free entries in a domain table
35 * @domain: the domain table to free (MAYBE NULL)
36 */
37void aa_free_domain_entries(struct aa_domain *domain)
38{
39 int i;
40 if (domain) {
41 if (!domain->table)
42 return;
43
44 for (i = 0; i < domain->size; i++)
45 kzfree(domain->table[i]);
46 kzfree(domain->table);
47 domain->table = NULL;
48 }
49}
50
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)
55 *
56 * Check if the task is ptraced and if so if the tracing task is allowed
57 * to trace the new domain
58 *
59 * Returns: %0 or error if change not allowed
60 */
61static int may_change_ptraced_domain(struct task_struct *task,
62 struct aa_profile *to_profile)
63{
64 struct task_struct *tracer;
James Morris77c80e62010-08-02 15:49:00 +100065 const struct cred *cred = NULL;
John Johansen898127c2010-07-29 14:48:06 -070066 struct aa_profile *tracerp = NULL;
67 int error = 0;
68
69 rcu_read_lock();
Tejun Heo06d98472011-06-17 16:50:40 +020070 tracer = ptrace_parent(task);
John Johansen898127c2010-07-29 14:48:06 -070071 if (tracer) {
72 /* released below */
73 cred = get_task_cred(tracer);
74 tracerp = aa_cred_profile(cred);
75 }
John Johansen898127c2010-07-29 14:48:06 -070076
77 /* not ptraced */
78 if (!tracer || unconfined(tracerp))
79 goto out;
80
81 error = aa_may_ptrace(tracer, tracerp, to_profile, PTRACE_MODE_ATTACH);
82
83out:
John Johansen04fdc092011-06-28 15:06:38 +010084 rcu_read_unlock();
John Johansen898127c2010-07-29 14:48:06 -070085 if (cred)
86 put_cred(cred);
87
88 return error;
89}
90
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
98 *
99 * Returns: permission set
100 */
101static 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)
105{
106 struct file_perms perms;
107 struct path_cond cond = { };
108 unsigned int state;
109
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;
121 }
122
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);
127
128 return perms;
129}
130
131/**
132 * __attach_match_ - find an attachment match
133 * @name - to match against (NOT NULL)
134 * @head - profile list to walk (NOT NULL)
135 *
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.
140 *
141 * Requires: @head not be shared or have appropriate locks held
142 *
143 * Returns: profile or NULL if no match found
144 */
145static struct aa_profile *__attach_match(const char *name,
146 struct list_head *head)
147{
148 int len = 0;
149 struct aa_profile *profile, *candidate = NULL;
150
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;
162 }
163 } else if (!strcmp(profile->base.name, name))
164 /* exact non-re match, no more searching required */
165 return profile;
166 }
167
168 return candidate;
169}
170
171/**
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)
176 *
177 * Returns: profile or NULL if no match found
178 */
179static struct aa_profile *find_attach(struct aa_namespace *ns,
180 struct list_head *list, const char *name)
181{
182 struct aa_profile *profile;
183
184 read_lock(&ns->lock);
185 profile = aa_get_profile(__attach_match(name, list));
186 read_unlock(&ns->lock);
187
188 return profile;
189}
190
191/**
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)
195 *
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.
200 *
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
207 *
208 * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table
209 *
210 * Returns: profile name if it is specified else NULL
211 */
212static const char *separate_fqname(const char *fqname, const char **ns_name)
213{
214 const char *name;
215
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
220 */
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;
228 }
229
230 return name;
231}
232
233static const char *next_name(int xtype, const char *name)
234{
235 return NULL;
236}
237
238/**
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
242 *
243 * Returns: refcounted profile, or NULL on failure (MAYBE NULL)
244 */
245static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex)
246{
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;
252
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;
258
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 */
273 ;
274 }
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;
285 }
286
287 /* released by caller */
288 new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname);
289 aa_put_namespace(new_ns);
290 }
291
292 /* released by caller */
293 return new_profile;
294}
295
296/**
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
301 *
302 * find profile for a transition index
303 *
304 * Returns: refcounted profile or NULL if not found available
305 */
306static struct aa_profile *x_to_profile(struct aa_profile *profile,
307 const char *name, u32 xindex)
308{
309 struct aa_profile *new_profile = NULL;
310 struct aa_namespace *ns = profile->ns;
311 u32 xtype = xindex & AA_X_TYPE_MASK;
312
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;
331 }
332
333 /* released by caller */
334 return new_profile;
335}
336
337/**
338 * apparmor_bprm_set_creds - set the new creds on the bprm struct
339 * @bprm: binprm for the exec (NOT NULL)
340 *
341 * Returns: %0 or error on failure
342 */
343int apparmor_bprm_set_creds(struct linux_binprm *bprm)
344{
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
354 };
355 const char *name = NULL, *target = NULL, *info = NULL;
356 int error = cap_bprm_set_creds(bprm);
357 if (error)
358 return error;
359
360 if (bprm->cred_prepared)
361 return 0;
362
363 cxt = bprm->cred->security;
364 BUG_ON(!cxt);
365
366 profile = aa_get_profile(aa_newest_version(cxt->profile));
367 /*
368 * get the namespace from the replacement profile as replacement
369 * can change the namespace
370 */
371 ns = profile->ns;
372 state = profile->file.start;
373
374 /* buffer freed below, name is pointer into buffer */
John Johansen57fa1e12012-02-16 06:20:33 -0800375 error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer,
376 &name, &info);
John Johansen898127c2010-07-29 14:48:06 -0700377 if (error) {
378 if (profile->flags &
379 (PFLAG_IX_ON_NAME_ERROR | PFLAG_UNCONFINED))
380 error = 0;
John Johansen898127c2010-07-29 14:48:06 -0700381 name = bprm->filename;
382 goto audit;
383 }
384
385 /* Test for onexec first as onexec directives override other
386 * x transitions.
387 */
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;
John Johansenc29bceb2012-04-12 16:47:51 -0500397 /*
398 * NOTE: Domain transitions from unconfined are allowed
399 * even when no_new_privs is set because this aways results
400 * in a further reduction of permissions.
401 */
John Johansen898127c2010-07-29 14:48:06 -0700402 goto apply;
403 }
404
405 /* find exec permissions for name */
406 state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
407 if (cxt->onexec) {
408 struct file_perms cp;
409 info = "change_profile onexec";
410 if (!(perms.allow & AA_MAY_ONEXEC))
411 goto audit;
412
413 /* test if this exec can be paired with change_profile onexec.
414 * onexec permission is linked to exec with a standard pairing
415 * exec\0change_profile
416 */
417 state = aa_dfa_null_transition(profile->file.dfa, state);
John Johansen0421ea92012-03-27 04:14:33 -0700418 cp = change_profile_perms(profile, cxt->onexec->ns,
419 cxt->onexec->base.name,
John Johansen898127c2010-07-29 14:48:06 -0700420 AA_MAY_ONEXEC, state);
421
422 if (!(cp.allow & AA_MAY_ONEXEC))
423 goto audit;
424 new_profile = aa_get_profile(aa_newest_version(cxt->onexec));
425 goto apply;
426 }
427
428 if (perms.allow & MAY_EXEC) {
429 /* exec permission determine how to transition */
430 new_profile = x_to_profile(profile, name, perms.xindex);
431 if (!new_profile) {
432 if (perms.xindex & AA_X_INHERIT) {
433 /* (p|c|n)ix - don't change profile but do
434 * use the newest version, which was picked
435 * up above when getting profile
436 */
437 info = "ix fallback";
438 new_profile = aa_get_profile(profile);
439 goto x_clear;
440 } else if (perms.xindex & AA_X_UNCONFINED) {
441 new_profile = aa_get_profile(ns->unconfined);
442 info = "ux fallback";
443 } else {
444 error = -ENOENT;
445 info = "profile not found";
446 }
447 }
448 } else if (COMPLAIN_MODE(profile)) {
449 /* no exec permission - are we in learning mode */
450 new_profile = aa_new_null_profile(profile, 0);
451 if (!new_profile) {
452 error = -ENOMEM;
453 info = "could not create null profile";
454 } else {
455 error = -EACCES;
456 target = new_profile->base.hname;
457 }
458 perms.xindex |= AA_X_UNSAFE;
459 } else
460 /* fail exec */
461 error = -EACCES;
462
John Johansenc29bceb2012-04-12 16:47:51 -0500463 /*
464 * Policy has specified a domain transition, if no_new_privs then
465 * fail the exec.
466 */
467 if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) {
468 aa_put_profile(new_profile);
469 error = -EPERM;
470 goto cleanup;
471 }
472
John Johansen898127c2010-07-29 14:48:06 -0700473 if (!new_profile)
474 goto audit;
475
476 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
477 /* FIXME: currently don't mediate shared state */
478 ;
479 }
480
481 if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
482 error = may_change_ptraced_domain(current, new_profile);
483 if (error) {
484 aa_put_profile(new_profile);
485 goto audit;
486 }
487 }
488
489 /* Determine if secure exec is needed.
490 * Can be at this point for the following reasons:
491 * 1. unconfined switching to confined
492 * 2. confined switching to different confinement
493 * 3. confined switching to unconfined
494 *
495 * Cases 2 and 3 are marked as requiring secure exec
496 * (unless policy specified "unsafe exec")
497 *
498 * bprm->unsafe is used to cache the AA_X_UNSAFE permission
499 * to avoid having to recompute in secureexec
500 */
501 if (!(perms.xindex & AA_X_UNSAFE)) {
502 AA_DEBUG("scrubbing environment variables for %s profile=%s\n",
503 name, new_profile->base.hname);
504 bprm->unsafe |= AA_SECURE_X_NEEDED;
505 }
506apply:
507 target = new_profile->base.hname;
508 /* when transitioning profiles clear unsafe personality bits */
509 bprm->per_clear |= PER_CLEAR_ON_SETID;
510
511x_clear:
512 aa_put_profile(cxt->profile);
513 /* transfer new profile reference will be released when cxt is freed */
514 cxt->profile = new_profile;
515
516 /* clear out all temporary/transitional state from the context */
517 aa_put_profile(cxt->previous);
518 aa_put_profile(cxt->onexec);
519 cxt->previous = NULL;
520 cxt->onexec = NULL;
521 cxt->token = 0;
522
523audit:
524 error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC,
525 name, target, cond.uid, info, error);
526
527cleanup:
528 aa_put_profile(profile);
529 kfree(buffer);
530
531 return error;
532}
533
534/**
535 * apparmor_bprm_secureexec - determine if secureexec is needed
536 * @bprm: binprm for exec (NOT NULL)
537 *
538 * Returns: %1 if secureexec is needed else %0
539 */
540int apparmor_bprm_secureexec(struct linux_binprm *bprm)
541{
542 int ret = cap_bprm_secureexec(bprm);
543
544 /* the decision to use secure exec is computed in set_creds
545 * and stored in bprm->unsafe.
546 */
547 if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED))
548 ret = 1;
549
550 return ret;
551}
552
553/**
554 * apparmor_bprm_committing_creds - do task cleanup on committing new creds
555 * @bprm: binprm for the exec (NOT NULL)
556 */
557void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
558{
559 struct aa_profile *profile = __aa_current_profile();
560 struct aa_task_cxt *new_cxt = bprm->cred->security;
561
562 /* bail out if unconfined or not changing profile */
563 if ((new_cxt->profile == profile) ||
564 (unconfined(new_cxt->profile)))
565 return;
566
567 current->pdeath_signal = 0;
568
569 /* reset soft limits and set hard limits for the new profile */
570 __aa_transition_rlimits(profile, new_cxt->profile);
571}
572
573/**
574 * apparmor_bprm_commited_cred - do cleanup after new creds committed
575 * @bprm: binprm for the exec (NOT NULL)
576 */
577void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
578{
579 /* TODO: cleanup signals - ipc mediation */
580 return;
581}
582
583/*
584 * Functions for self directed profile change
585 */
586
587/**
588 * new_compound_name - create an hname with @n2 appended to @n1
589 * @n1: base of hname (NOT NULL)
590 * @n2: name to append (NOT NULL)
591 *
592 * Returns: new name or NULL on error
593 */
594static char *new_compound_name(const char *n1, const char *n2)
595{
596 char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL);
597 if (name)
598 sprintf(name, "%s//%s", n1, n2);
599 return name;
600}
601
602/**
603 * aa_change_hat - change hat to/from subprofile
604 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
605 * @count: number of hat names in @hats
606 * @token: magic value to validate the hat change
607 * @permtest: true if this is just a permission test
608 *
609 * Change to the first profile specified in @hats that exists, and store
610 * the @hat_magic in the current task context. If the count == 0 and the
611 * @token matches that stored in the current task context, return to the
612 * top level profile.
613 *
614 * Returns %0 on success, error otherwise.
615 */
616int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
617{
618 const struct cred *cred;
619 struct aa_task_cxt *cxt;
620 struct aa_profile *profile, *previous_profile, *hat = NULL;
621 char *name = NULL;
622 int i;
623 struct file_perms perms = {};
624 const char *target = NULL, *info = NULL;
625 int error = 0;
626
John Johansenc29bceb2012-04-12 16:47:51 -0500627 /*
628 * Fail explicitly requested domain transitions if no_new_privs.
629 * There is no exception for unconfined as change_hat is not
630 * available.
631 */
632 if (current->no_new_privs)
633 return -EPERM;
634
John Johansen898127c2010-07-29 14:48:06 -0700635 /* released below */
636 cred = get_current_cred();
637 cxt = cred->security;
638 profile = aa_cred_profile(cred);
639 previous_profile = cxt->previous;
640
641 if (unconfined(profile)) {
642 info = "unconfined";
643 error = -EPERM;
644 goto audit;
645 }
646
647 if (count) {
648 /* attempting to change into a new hat or switch to a sibling */
649 struct aa_profile *root;
650 root = PROFILE_IS_HAT(profile) ? profile->parent : profile;
651
652 /* find first matching hat */
653 for (i = 0; i < count && !hat; i++)
654 /* released below */
655 hat = aa_find_child(root, hats[i]);
656 if (!hat) {
657 if (!COMPLAIN_MODE(root) || permtest) {
658 if (list_empty(&root->base.profiles))
659 error = -ECHILD;
660 else
661 error = -ENOENT;
662 goto out;
663 }
664
665 /*
666 * In complain mode and failed to match any hats.
667 * Audit the failure is based off of the first hat
668 * supplied. This is done due how userspace
669 * interacts with change_hat.
670 *
671 * TODO: Add logging of all failed hats
672 */
673
674 /* freed below */
675 name = new_compound_name(root->base.hname, hats[0]);
676 target = name;
677 /* released below */
678 hat = aa_new_null_profile(profile, 1);
679 if (!hat) {
680 info = "failed null profile create";
681 error = -ENOMEM;
682 goto audit;
683 }
684 } else {
685 target = hat->base.hname;
686 if (!PROFILE_IS_HAT(hat)) {
687 info = "target not hat";
688 error = -EPERM;
689 goto audit;
690 }
691 }
692
693 error = may_change_ptraced_domain(current, hat);
694 if (error) {
695 info = "ptraced";
696 error = -EPERM;
697 goto audit;
698 }
699
700 if (!permtest) {
701 error = aa_set_current_hat(hat, token);
702 if (error == -EACCES)
703 /* kill task in case of brute force attacks */
704 perms.kill = AA_MAY_CHANGEHAT;
705 else if (name && !error)
706 /* reset error for learning of new hats */
707 error = -ENOENT;
708 }
709 } else if (previous_profile) {
710 /* Return to saved profile. Kill task if restore fails
711 * to avoid brute force attacks
712 */
713 target = previous_profile->base.hname;
714 error = aa_restore_previous_profile(token);
715 perms.kill = AA_MAY_CHANGEHAT;
716 } else
717 /* ignore restores when there is no saved profile */
718 goto out;
719
720audit:
721 if (!permtest)
722 error = aa_audit_file(profile, &perms, GFP_KERNEL,
723 OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL,
Eric W. Biederman2db81452012-02-07 16:33:13 -0800724 target, GLOBAL_ROOT_UID, info, error);
John Johansen898127c2010-07-29 14:48:06 -0700725
726out:
727 aa_put_profile(hat);
728 kfree(name);
729 put_cred(cred);
730
731 return error;
732}
733
734/**
735 * aa_change_profile - perform a one-way profile transition
736 * @ns_name: name of the profile namespace to change to (MAYBE NULL)
737 * @hname: name of profile to change to (MAYBE NULL)
738 * @onexec: whether this transition is to take place immediately or at exec
739 * @permtest: true if this is just a permission test
740 *
741 * Change to new profile @name. Unlike with hats, there is no way
742 * to change back. If @name isn't specified the current profile name is
743 * used.
744 * If @onexec then the transition is delayed until
745 * the next exec.
746 *
747 * Returns %0 on success, error otherwise.
748 */
749int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
750 bool permtest)
751{
752 const struct cred *cred;
753 struct aa_task_cxt *cxt;
754 struct aa_profile *profile, *target = NULL;
755 struct aa_namespace *ns = NULL;
756 struct file_perms perms = {};
757 const char *name = NULL, *info = NULL;
758 int op, error = 0;
759 u32 request;
760
761 if (!hname && !ns_name)
762 return -EINVAL;
763
764 if (onexec) {
765 request = AA_MAY_ONEXEC;
766 op = OP_CHANGE_ONEXEC;
767 } else {
768 request = AA_MAY_CHANGE_PROFILE;
769 op = OP_CHANGE_PROFILE;
770 }
771
772 cred = get_current_cred();
773 cxt = cred->security;
774 profile = aa_cred_profile(cred);
775
John Johansenc29bceb2012-04-12 16:47:51 -0500776 /*
777 * Fail explicitly requested domain transitions if no_new_privs
778 * and not unconfined.
779 * Domain transitions from unconfined are allowed even when
780 * no_new_privs is set because this aways results in a reduction
781 * of permissions.
782 */
783 if (current->no_new_privs && !unconfined(profile)) {
784 put_cred(cred);
785 return -EPERM;
786 }
787
John Johansen898127c2010-07-29 14:48:06 -0700788 if (ns_name) {
789 /* released below */
790 ns = aa_find_namespace(profile->ns, ns_name);
791 if (!ns) {
792 /* we don't create new namespace in complain mode */
793 name = ns_name;
794 info = "namespace not found";
795 error = -ENOENT;
796 goto audit;
797 }
798 } else
799 /* released below */
800 ns = aa_get_namespace(profile->ns);
801
802 /* if the name was not specified, use the name of the current profile */
803 if (!hname) {
804 if (unconfined(profile))
805 hname = ns->unconfined->base.hname;
806 else
807 hname = profile->base.hname;
808 }
809
810 perms = change_profile_perms(profile, ns, hname, request,
811 profile->file.start);
812 if (!(perms.allow & request)) {
813 error = -EACCES;
814 goto audit;
815 }
816
817 /* released below */
818 target = aa_lookup_profile(ns, hname);
819 if (!target) {
820 info = "profile not found";
821 error = -ENOENT;
822 if (permtest || !COMPLAIN_MODE(profile))
823 goto audit;
824 /* released below */
825 target = aa_new_null_profile(profile, 0);
826 if (!target) {
827 info = "failed null profile create";
828 error = -ENOMEM;
829 goto audit;
830 }
831 }
832
833 /* check if tracing task is allowed to trace target domain */
834 error = may_change_ptraced_domain(current, target);
835 if (error) {
836 info = "ptrace prevents transition";
837 goto audit;
838 }
839
840 if (permtest)
841 goto audit;
842
843 if (onexec)
844 error = aa_set_current_onexec(target);
845 else
846 error = aa_replace_current_profile(target);
847
848audit:
849 if (!permtest)
850 error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request,
Eric W. Biederman2db81452012-02-07 16:33:13 -0800851 name, hname, GLOBAL_ROOT_UID, info, error);
John Johansen898127c2010-07-29 14:48:06 -0700852
853 aa_put_namespace(ns);
854 aa_put_profile(target);
855 put_cred(cred);
856
857 return error;
858}