blob: 01b7bd669a88d8d130f32097d0d3200a6068cbe5 [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;
John Johansen898127c2010-07-29 14:48:06 -070065 struct aa_profile *tracerp = NULL;
66 int error = 0;
67
68 rcu_read_lock();
Tejun Heo06d98472011-06-17 16:50:40 +020069 tracer = ptrace_parent(task);
John Johansen3cfcc192013-02-18 16:03:34 -080070 if (tracer)
John Johansen898127c2010-07-29 14:48:06 -070071 /* released below */
John Johansen3cfcc192013-02-18 16:03:34 -080072 tracerp = aa_get_task_profile(tracer);
John Johansen898127c2010-07-29 14:48:06 -070073
74 /* not ptraced */
75 if (!tracer || unconfined(tracerp))
76 goto out;
77
78 error = aa_may_ptrace(tracer, tracerp, to_profile, PTRACE_MODE_ATTACH);
79
80out:
John Johansen04fdc092011-06-28 15:06:38 +010081 rcu_read_unlock();
John Johansen3cfcc192013-02-18 16:03:34 -080082 aa_put_profile(tracerp);
John Johansen898127c2010-07-29 14:48:06 -070083
84 return error;
85}
86
87/**
88 * change_profile_perms - find permissions for change_profile
89 * @profile: the current profile (NOT NULL)
90 * @ns: the namespace being switched to (NOT NULL)
91 * @name: the name of the profile to change to (NOT NULL)
92 * @request: requested perms
93 * @start: state to start matching in
94 *
95 * Returns: permission set
96 */
97static struct file_perms change_profile_perms(struct aa_profile *profile,
98 struct aa_namespace *ns,
99 const char *name, u32 request,
100 unsigned int start)
101{
102 struct file_perms perms;
103 struct path_cond cond = { };
104 unsigned int state;
105
106 if (unconfined(profile)) {
107 perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
108 perms.audit = perms.quiet = perms.kill = 0;
109 return perms;
110 } else if (!profile->file.dfa) {
111 return nullperms;
112 } else if ((ns == profile->ns)) {
113 /* try matching against rules with out namespace prepended */
114 aa_str_perms(profile->file.dfa, start, name, &cond, &perms);
115 if (COMBINED_PERM_MASK(perms) & request)
116 return perms;
117 }
118
119 /* try matching with namespace name and then profile */
120 state = aa_dfa_match(profile->file.dfa, start, ns->base.name);
121 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
122 aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
123
124 return perms;
125}
126
127/**
128 * __attach_match_ - find an attachment match
129 * @name - to match against (NOT NULL)
130 * @head - profile list to walk (NOT NULL)
131 *
132 * Do a linear search on the profiles in the list. There is a matching
133 * preference where an exact match is preferred over a name which uses
134 * expressions to match, and matching expressions with the greatest
135 * xmatch_len are preferred.
136 *
137 * Requires: @head not be shared or have appropriate locks held
138 *
139 * Returns: profile or NULL if no match found
140 */
141static struct aa_profile *__attach_match(const char *name,
142 struct list_head *head)
143{
144 int len = 0;
145 struct aa_profile *profile, *candidate = NULL;
146
147 list_for_each_entry(profile, head, base.list) {
148 if (profile->flags & PFLAG_NULL)
149 continue;
150 if (profile->xmatch && profile->xmatch_len > len) {
151 unsigned int state = aa_dfa_match(profile->xmatch,
152 DFA_START, name);
153 u32 perm = dfa_user_allow(profile->xmatch, state);
154 /* any accepting state means a valid match. */
155 if (perm & MAY_EXEC) {
156 candidate = profile;
157 len = profile->xmatch_len;
158 }
159 } else if (!strcmp(profile->base.name, name))
160 /* exact non-re match, no more searching required */
161 return profile;
162 }
163
164 return candidate;
165}
166
167/**
168 * find_attach - do attachment search for unconfined processes
169 * @ns: the current namespace (NOT NULL)
170 * @list: list to search (NOT NULL)
171 * @name: the executable name to match against (NOT NULL)
172 *
173 * Returns: profile or NULL if no match found
174 */
175static struct aa_profile *find_attach(struct aa_namespace *ns,
176 struct list_head *list, const char *name)
177{
178 struct aa_profile *profile;
179
180 read_lock(&ns->lock);
181 profile = aa_get_profile(__attach_match(name, list));
182 read_unlock(&ns->lock);
183
184 return profile;
185}
186
187/**
188 * separate_fqname - separate the namespace and profile names
189 * @fqname: the fqname name to split (NOT NULL)
190 * @ns_name: the namespace name if it exists (NOT NULL)
191 *
192 * This is the xtable equivalent routine of aa_split_fqname. It finds the
193 * split in an xtable fqname which contains an embedded \0 instead of a :
194 * if a namespace is specified. This is done so the xtable is constant and
195 * isn't re-split on every lookup.
196 *
197 * Either the profile or namespace name may be optional but if the namespace
198 * is specified the profile name termination must be present. This results
199 * in the following possible encodings:
200 * profile_name\0
201 * :ns_name\0profile_name\0
202 * :ns_name\0\0
203 *
204 * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table
205 *
206 * Returns: profile name if it is specified else NULL
207 */
208static const char *separate_fqname(const char *fqname, const char **ns_name)
209{
210 const char *name;
211
212 if (fqname[0] == ':') {
213 /* In this case there is guaranteed to be two \0 terminators
214 * in the string. They are verified at load time by
215 * by unpack_trans_table
216 */
217 *ns_name = fqname + 1; /* skip : */
218 name = *ns_name + strlen(*ns_name) + 1;
219 if (!*name)
220 name = NULL;
221 } else {
222 *ns_name = NULL;
223 name = fqname;
224 }
225
226 return name;
227}
228
229static const char *next_name(int xtype, const char *name)
230{
231 return NULL;
232}
233
234/**
235 * x_table_lookup - lookup an x transition name via transition table
236 * @profile: current profile (NOT NULL)
237 * @xindex: index into x transition table
238 *
239 * Returns: refcounted profile, or NULL on failure (MAYBE NULL)
240 */
241static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex)
242{
243 struct aa_profile *new_profile = NULL;
244 struct aa_namespace *ns = profile->ns;
245 u32 xtype = xindex & AA_X_TYPE_MASK;
246 int index = xindex & AA_X_INDEX_MASK;
247 const char *name;
248
249 /* index is guaranteed to be in range, validated at load time */
250 for (name = profile->file.trans.table[index]; !new_profile && name;
251 name = next_name(xtype, name)) {
252 struct aa_namespace *new_ns;
253 const char *xname = NULL;
254
255 new_ns = NULL;
256 if (xindex & AA_X_CHILD) {
257 /* release by caller */
258 new_profile = aa_find_child(profile, name);
259 continue;
260 } else if (*name == ':') {
261 /* switching namespace */
262 const char *ns_name;
263 xname = name = separate_fqname(name, &ns_name);
264 if (!xname)
265 /* no name so use profile name */
266 xname = profile->base.hname;
267 if (*ns_name == '@') {
268 /* TODO: variable support */
269 ;
270 }
271 /* released below */
272 new_ns = aa_find_namespace(ns, ns_name);
273 if (!new_ns)
274 continue;
275 } else if (*name == '@') {
276 /* TODO: variable support */
277 continue;
278 } else {
279 /* basic namespace lookup */
280 xname = name;
281 }
282
283 /* released by caller */
284 new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname);
285 aa_put_namespace(new_ns);
286 }
287
288 /* released by caller */
289 return new_profile;
290}
291
292/**
293 * x_to_profile - get target profile for a given xindex
294 * @profile: current profile (NOT NULL)
295 * @name: name to lookup (NOT NULL)
296 * @xindex: index into x transition table
297 *
298 * find profile for a transition index
299 *
300 * Returns: refcounted profile or NULL if not found available
301 */
302static struct aa_profile *x_to_profile(struct aa_profile *profile,
303 const char *name, u32 xindex)
304{
305 struct aa_profile *new_profile = NULL;
306 struct aa_namespace *ns = profile->ns;
307 u32 xtype = xindex & AA_X_TYPE_MASK;
308
309 switch (xtype) {
310 case AA_X_NONE:
311 /* fail exec unless ix || ux fallback - handled by caller */
312 return NULL;
313 case AA_X_NAME:
314 if (xindex & AA_X_CHILD)
315 /* released by caller */
316 new_profile = find_attach(ns, &profile->base.profiles,
317 name);
318 else
319 /* released by caller */
320 new_profile = find_attach(ns, &ns->base.profiles,
321 name);
322 break;
323 case AA_X_TABLE:
324 /* released by caller */
325 new_profile = x_table_lookup(profile, xindex);
326 break;
327 }
328
329 /* released by caller */
330 return new_profile;
331}
332
333/**
334 * apparmor_bprm_set_creds - set the new creds on the bprm struct
335 * @bprm: binprm for the exec (NOT NULL)
336 *
337 * Returns: %0 or error on failure
338 */
339int apparmor_bprm_set_creds(struct linux_binprm *bprm)
340{
341 struct aa_task_cxt *cxt;
342 struct aa_profile *profile, *new_profile = NULL;
343 struct aa_namespace *ns;
344 char *buffer = NULL;
345 unsigned int state;
346 struct file_perms perms = {};
347 struct path_cond cond = {
Al Viro496ad9a2013-01-23 17:07:38 -0500348 file_inode(bprm->file)->i_uid,
349 file_inode(bprm->file)->i_mode
John Johansen898127c2010-07-29 14:48:06 -0700350 };
351 const char *name = NULL, *target = NULL, *info = NULL;
352 int error = cap_bprm_set_creds(bprm);
353 if (error)
354 return error;
355
356 if (bprm->cred_prepared)
357 return 0;
358
John Johansen214beac2013-02-27 03:43:40 -0800359 cxt = cred_cxt(bprm->cred);
John Johansen898127c2010-07-29 14:48:06 -0700360 BUG_ON(!cxt);
361
362 profile = aa_get_profile(aa_newest_version(cxt->profile));
363 /*
364 * get the namespace from the replacement profile as replacement
365 * can change the namespace
366 */
367 ns = profile->ns;
368 state = profile->file.start;
369
370 /* buffer freed below, name is pointer into buffer */
John Johansen57fa1e12012-02-16 06:20:33 -0800371 error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer,
372 &name, &info);
John Johansen898127c2010-07-29 14:48:06 -0700373 if (error) {
374 if (profile->flags &
375 (PFLAG_IX_ON_NAME_ERROR | PFLAG_UNCONFINED))
376 error = 0;
John Johansen898127c2010-07-29 14:48:06 -0700377 name = bprm->filename;
378 goto audit;
379 }
380
381 /* Test for onexec first as onexec directives override other
382 * x transitions.
383 */
384 if (unconfined(profile)) {
385 /* unconfined task */
386 if (cxt->onexec)
387 /* change_profile on exec already been granted */
388 new_profile = aa_get_profile(cxt->onexec);
389 else
390 new_profile = find_attach(ns, &ns->base.profiles, name);
391 if (!new_profile)
392 goto cleanup;
John Johansenc29bceb2012-04-12 16:47:51 -0500393 /*
394 * NOTE: Domain transitions from unconfined are allowed
395 * even when no_new_privs is set because this aways results
396 * in a further reduction of permissions.
397 */
John Johansen898127c2010-07-29 14:48:06 -0700398 goto apply;
399 }
400
401 /* find exec permissions for name */
402 state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
403 if (cxt->onexec) {
404 struct file_perms cp;
405 info = "change_profile onexec";
406 if (!(perms.allow & AA_MAY_ONEXEC))
407 goto audit;
408
409 /* test if this exec can be paired with change_profile onexec.
410 * onexec permission is linked to exec with a standard pairing
411 * exec\0change_profile
412 */
413 state = aa_dfa_null_transition(profile->file.dfa, state);
John Johansen0421ea92012-03-27 04:14:33 -0700414 cp = change_profile_perms(profile, cxt->onexec->ns,
415 cxt->onexec->base.name,
John Johansen898127c2010-07-29 14:48:06 -0700416 AA_MAY_ONEXEC, state);
417
418 if (!(cp.allow & AA_MAY_ONEXEC))
419 goto audit;
420 new_profile = aa_get_profile(aa_newest_version(cxt->onexec));
421 goto apply;
422 }
423
424 if (perms.allow & MAY_EXEC) {
425 /* exec permission determine how to transition */
426 new_profile = x_to_profile(profile, name, perms.xindex);
427 if (!new_profile) {
428 if (perms.xindex & AA_X_INHERIT) {
429 /* (p|c|n)ix - don't change profile but do
430 * use the newest version, which was picked
431 * up above when getting profile
432 */
433 info = "ix fallback";
434 new_profile = aa_get_profile(profile);
435 goto x_clear;
436 } else if (perms.xindex & AA_X_UNCONFINED) {
437 new_profile = aa_get_profile(ns->unconfined);
438 info = "ux fallback";
439 } else {
440 error = -ENOENT;
441 info = "profile not found";
John Johansen17322cc2013-02-18 15:59:34 -0800442 /* remove MAY_EXEC to audit as failure */
443 perms.allow &= ~MAY_EXEC;
John Johansen898127c2010-07-29 14:48:06 -0700444 }
445 }
446 } else if (COMPLAIN_MODE(profile)) {
447 /* no exec permission - are we in learning mode */
448 new_profile = aa_new_null_profile(profile, 0);
449 if (!new_profile) {
450 error = -ENOMEM;
451 info = "could not create null profile";
452 } else {
453 error = -EACCES;
454 target = new_profile->base.hname;
455 }
456 perms.xindex |= AA_X_UNSAFE;
457 } else
458 /* fail exec */
459 error = -EACCES;
460
John Johansenc29bceb2012-04-12 16:47:51 -0500461 /*
462 * Policy has specified a domain transition, if no_new_privs then
463 * fail the exec.
464 */
465 if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) {
466 aa_put_profile(new_profile);
467 error = -EPERM;
468 goto cleanup;
469 }
470
John Johansen898127c2010-07-29 14:48:06 -0700471 if (!new_profile)
472 goto audit;
473
474 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
475 /* FIXME: currently don't mediate shared state */
476 ;
477 }
478
479 if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
480 error = may_change_ptraced_domain(current, new_profile);
481 if (error) {
482 aa_put_profile(new_profile);
483 goto audit;
484 }
485 }
486
487 /* Determine if secure exec is needed.
488 * Can be at this point for the following reasons:
489 * 1. unconfined switching to confined
490 * 2. confined switching to different confinement
491 * 3. confined switching to unconfined
492 *
493 * Cases 2 and 3 are marked as requiring secure exec
494 * (unless policy specified "unsafe exec")
495 *
496 * bprm->unsafe is used to cache the AA_X_UNSAFE permission
497 * to avoid having to recompute in secureexec
498 */
499 if (!(perms.xindex & AA_X_UNSAFE)) {
500 AA_DEBUG("scrubbing environment variables for %s profile=%s\n",
501 name, new_profile->base.hname);
502 bprm->unsafe |= AA_SECURE_X_NEEDED;
503 }
504apply:
505 target = new_profile->base.hname;
506 /* when transitioning profiles clear unsafe personality bits */
507 bprm->per_clear |= PER_CLEAR_ON_SETID;
508
509x_clear:
510 aa_put_profile(cxt->profile);
511 /* transfer new profile reference will be released when cxt is freed */
512 cxt->profile = new_profile;
513
514 /* clear out all temporary/transitional state from the context */
John Johansen7a2871b2013-02-18 16:05:34 -0800515 aa_clear_task_cxt_trans(cxt);
John Johansen898127c2010-07-29 14:48:06 -0700516
517audit:
518 error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC,
519 name, target, cond.uid, info, error);
520
521cleanup:
522 aa_put_profile(profile);
523 kfree(buffer);
524
525 return error;
526}
527
528/**
529 * apparmor_bprm_secureexec - determine if secureexec is needed
530 * @bprm: binprm for exec (NOT NULL)
531 *
532 * Returns: %1 if secureexec is needed else %0
533 */
534int apparmor_bprm_secureexec(struct linux_binprm *bprm)
535{
536 int ret = cap_bprm_secureexec(bprm);
537
538 /* the decision to use secure exec is computed in set_creds
539 * and stored in bprm->unsafe.
540 */
541 if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED))
542 ret = 1;
543
544 return ret;
545}
546
547/**
548 * apparmor_bprm_committing_creds - do task cleanup on committing new creds
549 * @bprm: binprm for the exec (NOT NULL)
550 */
551void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
552{
553 struct aa_profile *profile = __aa_current_profile();
John Johansen214beac2013-02-27 03:43:40 -0800554 struct aa_task_cxt *new_cxt = cred_cxt(bprm->cred);
John Johansen898127c2010-07-29 14:48:06 -0700555
556 /* bail out if unconfined or not changing profile */
557 if ((new_cxt->profile == profile) ||
558 (unconfined(new_cxt->profile)))
559 return;
560
561 current->pdeath_signal = 0;
562
563 /* reset soft limits and set hard limits for the new profile */
564 __aa_transition_rlimits(profile, new_cxt->profile);
565}
566
567/**
568 * apparmor_bprm_commited_cred - do cleanup after new creds committed
569 * @bprm: binprm for the exec (NOT NULL)
570 */
571void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
572{
573 /* TODO: cleanup signals - ipc mediation */
574 return;
575}
576
577/*
578 * Functions for self directed profile change
579 */
580
581/**
582 * new_compound_name - create an hname with @n2 appended to @n1
583 * @n1: base of hname (NOT NULL)
584 * @n2: name to append (NOT NULL)
585 *
586 * Returns: new name or NULL on error
587 */
588static char *new_compound_name(const char *n1, const char *n2)
589{
590 char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL);
591 if (name)
592 sprintf(name, "%s//%s", n1, n2);
593 return name;
594}
595
596/**
597 * aa_change_hat - change hat to/from subprofile
598 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
599 * @count: number of hat names in @hats
600 * @token: magic value to validate the hat change
601 * @permtest: true if this is just a permission test
602 *
603 * Change to the first profile specified in @hats that exists, and store
604 * the @hat_magic in the current task context. If the count == 0 and the
605 * @token matches that stored in the current task context, return to the
606 * top level profile.
607 *
608 * Returns %0 on success, error otherwise.
609 */
610int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
611{
612 const struct cred *cred;
613 struct aa_task_cxt *cxt;
614 struct aa_profile *profile, *previous_profile, *hat = NULL;
615 char *name = NULL;
616 int i;
617 struct file_perms perms = {};
618 const char *target = NULL, *info = NULL;
619 int error = 0;
620
John Johansenc29bceb2012-04-12 16:47:51 -0500621 /*
622 * Fail explicitly requested domain transitions if no_new_privs.
623 * There is no exception for unconfined as change_hat is not
624 * available.
625 */
626 if (current->no_new_privs)
627 return -EPERM;
628
John Johansen898127c2010-07-29 14:48:06 -0700629 /* released below */
630 cred = get_current_cred();
John Johansen214beac2013-02-27 03:43:40 -0800631 cxt = cred_cxt(cred);
John Johansen898127c2010-07-29 14:48:06 -0700632 profile = aa_cred_profile(cred);
633 previous_profile = cxt->previous;
634
635 if (unconfined(profile)) {
636 info = "unconfined";
637 error = -EPERM;
638 goto audit;
639 }
640
641 if (count) {
642 /* attempting to change into a new hat or switch to a sibling */
643 struct aa_profile *root;
644 root = PROFILE_IS_HAT(profile) ? profile->parent : profile;
645
646 /* find first matching hat */
647 for (i = 0; i < count && !hat; i++)
648 /* released below */
649 hat = aa_find_child(root, hats[i]);
650 if (!hat) {
651 if (!COMPLAIN_MODE(root) || permtest) {
652 if (list_empty(&root->base.profiles))
653 error = -ECHILD;
654 else
655 error = -ENOENT;
656 goto out;
657 }
658
659 /*
660 * In complain mode and failed to match any hats.
661 * Audit the failure is based off of the first hat
662 * supplied. This is done due how userspace
663 * interacts with change_hat.
664 *
665 * TODO: Add logging of all failed hats
666 */
667
668 /* freed below */
669 name = new_compound_name(root->base.hname, hats[0]);
670 target = name;
671 /* released below */
672 hat = aa_new_null_profile(profile, 1);
673 if (!hat) {
674 info = "failed null profile create";
675 error = -ENOMEM;
676 goto audit;
677 }
678 } else {
679 target = hat->base.hname;
680 if (!PROFILE_IS_HAT(hat)) {
681 info = "target not hat";
682 error = -EPERM;
683 goto audit;
684 }
685 }
686
687 error = may_change_ptraced_domain(current, hat);
688 if (error) {
689 info = "ptraced";
690 error = -EPERM;
691 goto audit;
692 }
693
694 if (!permtest) {
695 error = aa_set_current_hat(hat, token);
696 if (error == -EACCES)
697 /* kill task in case of brute force attacks */
698 perms.kill = AA_MAY_CHANGEHAT;
699 else if (name && !error)
700 /* reset error for learning of new hats */
701 error = -ENOENT;
702 }
703 } else if (previous_profile) {
704 /* Return to saved profile. Kill task if restore fails
705 * to avoid brute force attacks
706 */
707 target = previous_profile->base.hname;
708 error = aa_restore_previous_profile(token);
709 perms.kill = AA_MAY_CHANGEHAT;
710 } else
711 /* ignore restores when there is no saved profile */
712 goto out;
713
714audit:
715 if (!permtest)
716 error = aa_audit_file(profile, &perms, GFP_KERNEL,
717 OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL,
Eric W. Biederman2db81452012-02-07 16:33:13 -0800718 target, GLOBAL_ROOT_UID, info, error);
John Johansen898127c2010-07-29 14:48:06 -0700719
720out:
721 aa_put_profile(hat);
722 kfree(name);
723 put_cred(cred);
724
725 return error;
726}
727
728/**
729 * aa_change_profile - perform a one-way profile transition
730 * @ns_name: name of the profile namespace to change to (MAYBE NULL)
731 * @hname: name of profile to change to (MAYBE NULL)
732 * @onexec: whether this transition is to take place immediately or at exec
733 * @permtest: true if this is just a permission test
734 *
735 * Change to new profile @name. Unlike with hats, there is no way
736 * to change back. If @name isn't specified the current profile name is
737 * used.
738 * If @onexec then the transition is delayed until
739 * the next exec.
740 *
741 * Returns %0 on success, error otherwise.
742 */
743int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
744 bool permtest)
745{
746 const struct cred *cred;
John Johansen898127c2010-07-29 14:48:06 -0700747 struct aa_profile *profile, *target = NULL;
748 struct aa_namespace *ns = NULL;
749 struct file_perms perms = {};
750 const char *name = NULL, *info = NULL;
751 int op, error = 0;
752 u32 request;
753
754 if (!hname && !ns_name)
755 return -EINVAL;
756
757 if (onexec) {
758 request = AA_MAY_ONEXEC;
759 op = OP_CHANGE_ONEXEC;
760 } else {
761 request = AA_MAY_CHANGE_PROFILE;
762 op = OP_CHANGE_PROFILE;
763 }
764
765 cred = get_current_cred();
John Johansen898127c2010-07-29 14:48:06 -0700766 profile = aa_cred_profile(cred);
767
John Johansenc29bceb2012-04-12 16:47:51 -0500768 /*
769 * Fail explicitly requested domain transitions if no_new_privs
770 * and not unconfined.
771 * Domain transitions from unconfined are allowed even when
772 * no_new_privs is set because this aways results in a reduction
773 * of permissions.
774 */
775 if (current->no_new_privs && !unconfined(profile)) {
776 put_cred(cred);
777 return -EPERM;
778 }
779
John Johansen898127c2010-07-29 14:48:06 -0700780 if (ns_name) {
781 /* released below */
782 ns = aa_find_namespace(profile->ns, ns_name);
783 if (!ns) {
784 /* we don't create new namespace in complain mode */
785 name = ns_name;
786 info = "namespace not found";
787 error = -ENOENT;
788 goto audit;
789 }
790 } else
791 /* released below */
792 ns = aa_get_namespace(profile->ns);
793
794 /* if the name was not specified, use the name of the current profile */
795 if (!hname) {
796 if (unconfined(profile))
797 hname = ns->unconfined->base.hname;
798 else
799 hname = profile->base.hname;
800 }
801
802 perms = change_profile_perms(profile, ns, hname, request,
803 profile->file.start);
804 if (!(perms.allow & request)) {
805 error = -EACCES;
806 goto audit;
807 }
808
809 /* released below */
810 target = aa_lookup_profile(ns, hname);
811 if (!target) {
812 info = "profile not found";
813 error = -ENOENT;
814 if (permtest || !COMPLAIN_MODE(profile))
815 goto audit;
816 /* released below */
817 target = aa_new_null_profile(profile, 0);
818 if (!target) {
819 info = "failed null profile create";
820 error = -ENOMEM;
821 goto audit;
822 }
823 }
824
825 /* check if tracing task is allowed to trace target domain */
826 error = may_change_ptraced_domain(current, target);
827 if (error) {
828 info = "ptrace prevents transition";
829 goto audit;
830 }
831
832 if (permtest)
833 goto audit;
834
835 if (onexec)
836 error = aa_set_current_onexec(target);
837 else
838 error = aa_replace_current_profile(target);
839
840audit:
841 if (!permtest)
842 error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request,
Eric W. Biederman2db81452012-02-07 16:33:13 -0800843 name, hname, GLOBAL_ROOT_UID, info, error);
John Johansen898127c2010-07-29 14:48:06 -0700844
845 aa_put_namespace(ns);
846 aa_put_profile(target);
847 put_cred(cred);
848
849 return error;
850}