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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AppArmor security module
4 *
5 * This file contains AppArmor policy attachment and domain transitions
6 *
7 * Copyright (C) 2002-2008 Novell/SUSE
8 * Copyright 2009-2010 Canonical Ltd.
9 */
10
11#include <linux/errno.h>
12#include <linux/fdtable.h>
13#include <linux/file.h>
14#include <linux/mount.h>
15#include <linux/syscalls.h>
16#include <linux/tracehook.h>
17#include <linux/personality.h>
18#include <linux/xattr.h>
19
20#include "include/audit.h"
21#include "include/apparmorfs.h"
22#include "include/cred.h"
23#include "include/domain.h"
24#include "include/file.h"
25#include "include/ipc.h"
26#include "include/match.h"
27#include "include/path.h"
28#include "include/policy.h"
29#include "include/policy_ns.h"
30
31/**
32 * aa_free_domain_entries - free entries in a domain table
33 * @domain: the domain table to free (MAYBE NULL)
34 */
35void aa_free_domain_entries(struct aa_domain *domain)
36{
37 int i;
38 if (domain) {
39 if (!domain->table)
40 return;
41
42 for (i = 0; i < domain->size; i++)
43 kzfree(domain->table[i]);
44 kzfree(domain->table);
45 domain->table = NULL;
46 }
47}
48
49/**
50 * may_change_ptraced_domain - check if can change profile on ptraced task
51 * @to_label: profile to change to (NOT NULL)
52 * @info: message if there is an error
53 *
54 * Check if current is ptraced and if so if the tracing task is allowed
55 * to trace the new domain
56 *
57 * Returns: %0 or error if change not allowed
58 */
59static int may_change_ptraced_domain(struct aa_label *to_label,
60 const char **info)
61{
62 struct task_struct *tracer;
63 struct aa_label *tracerl = NULL;
64 int error = 0;
65
66 rcu_read_lock();
67 tracer = ptrace_parent(current);
68 if (tracer)
69 /* released below */
70 tracerl = aa_get_task_label(tracer);
71
72 /* not ptraced */
73 if (!tracer || unconfined(tracerl))
74 goto out;
75
76 error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH);
77
78out:
79 rcu_read_unlock();
80 aa_put_label(tracerl);
81
82 if (error)
83 *info = "ptrace prevents transition";
84 return error;
85}
86
87/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
88 * specifically this is an exact copy of aa_label_match except
89 * aa_compute_perms is replaced with aa_compute_fperms
90 * and policy.dfa with file.dfa
91 ****/
92/* match a profile and its associated ns component if needed
93 * Assumes visibility test has already been done.
94 * If a subns profile is not to be matched should be prescreened with
95 * visibility test.
96 */
97static inline unsigned int match_component(struct aa_profile *profile,
98 struct aa_profile *tp,
99 bool stack, unsigned int state)
100{
101 const char *ns_name;
102
103 if (stack)
104 state = aa_dfa_match(profile->file.dfa, state, "&");
105 if (profile->ns == tp->ns)
106 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
107
108 /* try matching with namespace name and then profile */
109 ns_name = aa_ns_name(profile->ns, tp->ns, true);
110 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
111 state = aa_dfa_match(profile->file.dfa, state, ns_name);
112 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
113 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
114}
115
116/**
117 * label_compound_match - find perms for full compound label
118 * @profile: profile to find perms for
119 * @label: label to check access permissions for
120 * @stack: whether this is a stacking request
121 * @start: state to start match in
122 * @subns: whether to do permission checks on components in a subns
123 * @request: permissions to request
124 * @perms: perms struct to set
125 *
126 * Returns: 0 on success else ERROR
127 *
128 * For the label A//&B//&C this does the perm match for A//&B//&C
129 * @perms should be preinitialized with allperms OR a previous permission
130 * check to be stacked.
131 */
132static int label_compound_match(struct aa_profile *profile,
133 struct aa_label *label, bool stack,
134 unsigned int state, bool subns, u32 request,
135 struct aa_perms *perms)
136{
137 struct aa_profile *tp;
138 struct label_it i;
139 struct path_cond cond = { };
140
141 /* find first subcomponent that is visible */
142 label_for_each(i, label, tp) {
143 if (!aa_ns_visible(profile->ns, tp->ns, subns))
144 continue;
145 state = match_component(profile, tp, stack, state);
146 if (!state)
147 goto fail;
148 goto next;
149 }
150
151 /* no component visible */
152 *perms = allperms;
153 return 0;
154
155next:
156 label_for_each_cont(i, label, tp) {
157 if (!aa_ns_visible(profile->ns, tp->ns, subns))
158 continue;
159 state = aa_dfa_match(profile->file.dfa, state, "//&");
160 state = match_component(profile, tp, false, state);
161 if (!state)
162 goto fail;
163 }
164 *perms = aa_compute_fperms(profile->file.dfa, state, &cond);
165 aa_apply_modes_to_perms(profile, perms);
166 if ((perms->allow & request) != request)
167 return -EACCES;
168
169 return 0;
170
171fail:
172 *perms = nullperms;
173 return -EACCES;
174}
175
176/**
177 * label_components_match - find perms for all subcomponents of a label
178 * @profile: profile to find perms for
179 * @label: label to check access permissions for
180 * @stack: whether this is a stacking request
181 * @start: state to start match in
182 * @subns: whether to do permission checks on components in a subns
183 * @request: permissions to request
184 * @perms: an initialized perms struct to add accumulation to
185 *
186 * Returns: 0 on success else ERROR
187 *
188 * For the label A//&B//&C this does the perm match for each of A and B and C
189 * @perms should be preinitialized with allperms OR a previous permission
190 * check to be stacked.
191 */
192static int label_components_match(struct aa_profile *profile,
193 struct aa_label *label, bool stack,
194 unsigned int start, bool subns, u32 request,
195 struct aa_perms *perms)
196{
197 struct aa_profile *tp;
198 struct label_it i;
199 struct aa_perms tmp;
200 struct path_cond cond = { };
201 unsigned int state = 0;
202
203 /* find first subcomponent to test */
204 label_for_each(i, label, tp) {
205 if (!aa_ns_visible(profile->ns, tp->ns, subns))
206 continue;
207 state = match_component(profile, tp, stack, start);
208 if (!state)
209 goto fail;
210 goto next;
211 }
212
213 /* no subcomponents visible - no change in perms */
214 return 0;
215
216next:
217 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
218 aa_apply_modes_to_perms(profile, &tmp);
219 aa_perms_accum(perms, &tmp);
220 label_for_each_cont(i, label, tp) {
221 if (!aa_ns_visible(profile->ns, tp->ns, subns))
222 continue;
223 state = match_component(profile, tp, stack, start);
224 if (!state)
225 goto fail;
226 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
227 aa_apply_modes_to_perms(profile, &tmp);
228 aa_perms_accum(perms, &tmp);
229 }
230
231 if ((perms->allow & request) != request)
232 return -EACCES;
233
234 return 0;
235
236fail:
237 *perms = nullperms;
238 return -EACCES;
239}
240
241/**
242 * label_match - do a multi-component label match
243 * @profile: profile to match against (NOT NULL)
244 * @label: label to match (NOT NULL)
245 * @stack: whether this is a stacking request
246 * @state: state to start in
247 * @subns: whether to match subns components
248 * @request: permission request
249 * @perms: Returns computed perms (NOT NULL)
250 *
251 * Returns: the state the match finished in, may be the none matching state
252 */
253static int label_match(struct aa_profile *profile, struct aa_label *label,
254 bool stack, unsigned int state, bool subns, u32 request,
255 struct aa_perms *perms)
256{
257 int error;
258
259 *perms = nullperms;
260 error = label_compound_match(profile, label, stack, state, subns,
261 request, perms);
262 if (!error)
263 return error;
264
265 *perms = allperms;
266 return label_components_match(profile, label, stack, state, subns,
267 request, perms);
268}
269
270/******* end TODO: dedup *****/
271
272/**
273 * change_profile_perms - find permissions for change_profile
274 * @profile: the current profile (NOT NULL)
275 * @target: label to transition to (NOT NULL)
276 * @stack: whether this is a stacking request
277 * @request: requested perms
278 * @start: state to start matching in
279 *
280 *
281 * Returns: permission set
282 *
283 * currently only matches full label A//&B//&C or individual components A, B, C
284 * not arbitrary combinations. Eg. A//&B, C
285 */
286static int change_profile_perms(struct aa_profile *profile,
287 struct aa_label *target, bool stack,
288 u32 request, unsigned int start,
289 struct aa_perms *perms)
290{
291 if (profile_unconfined(profile)) {
292 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
293 perms->audit = perms->quiet = perms->kill = 0;
294 return 0;
295 }
296
297 /* TODO: add profile in ns screening */
298 return label_match(profile, target, stack, start, true, request, perms);
299}
300
301/**
302 * aa_xattrs_match - check whether a file matches the xattrs defined in profile
303 * @bprm: binprm struct for the process to validate
304 * @profile: profile to match against (NOT NULL)
305 * @state: state to start match in
306 *
307 * Returns: number of extended attributes that matched, or < 0 on error
308 */
309static int aa_xattrs_match(const struct linux_binprm *bprm,
310 struct aa_profile *profile, unsigned int state)
311{
312 int i;
313 ssize_t size;
314 struct dentry *d;
315 char *value = NULL;
316 int value_size = 0, ret = profile->xattr_count;
317
318 if (!bprm || !profile->xattr_count)
319 return 0;
320
321 /* transition from exec match to xattr set */
322 state = aa_dfa_null_transition(profile->xmatch, state);
323
324 d = bprm->file->f_path.dentry;
325
326 for (i = 0; i < profile->xattr_count; i++) {
327 size = vfs_getxattr_alloc(d, profile->xattrs[i], &value,
328 value_size, GFP_KERNEL);
329 if (size >= 0) {
330 u32 perm;
331
332 /* Check the xattr value, not just presence */
333 state = aa_dfa_match_len(profile->xmatch, state, value,
334 size);
335 perm = dfa_user_allow(profile->xmatch, state);
336 if (!(perm & MAY_EXEC)) {
337 ret = -EINVAL;
338 goto out;
339 }
340 }
341 /* transition to next element */
342 state = aa_dfa_null_transition(profile->xmatch, state);
343 if (size < 0) {
344 /*
345 * No xattr match, so verify if transition to
346 * next element was valid. IFF so the xattr
347 * was optional.
348 */
349 if (!state) {
350 ret = -EINVAL;
351 goto out;
352 }
353 /* don't count missing optional xattr as matched */
354 ret--;
355 }
356 }
357
358out:
359 kfree(value);
360 return ret;
361}
362
363/**
364 * __attach_match_ - find an attachment match
365 * @bprm - binprm structure of transitioning task
366 * @name - to match against (NOT NULL)
367 * @head - profile list to walk (NOT NULL)
368 * @info - info message if there was an error (NOT NULL)
369 *
370 * Do a linear search on the profiles in the list. There is a matching
371 * preference where an exact match is preferred over a name which uses
372 * expressions to match, and matching expressions with the greatest
373 * xmatch_len are preferred.
374 *
375 * Requires: @head not be shared or have appropriate locks held
376 *
377 * Returns: profile or NULL if no match found
378 */
379static struct aa_profile *__attach_match(const struct linux_binprm *bprm,
380 const char *name,
381 struct list_head *head,
382 const char **info)
383{
384 int candidate_len = 0, candidate_xattrs = 0;
385 bool conflict = false;
386 struct aa_profile *profile, *candidate = NULL;
387
388 AA_BUG(!name);
389 AA_BUG(!head);
390
391 list_for_each_entry_rcu(profile, head, base.list) {
392 if (profile->label.flags & FLAG_NULL &&
393 &profile->label == ns_unconfined(profile->ns))
394 continue;
395
396 /* Find the "best" matching profile. Profiles must
397 * match the path and extended attributes (if any)
398 * associated with the file. A more specific path
399 * match will be preferred over a less specific one,
400 * and a match with more matching extended attributes
401 * will be preferred over one with fewer. If the best
402 * match has both the same level of path specificity
403 * and the same number of matching extended attributes
404 * as another profile, signal a conflict and refuse to
405 * match.
406 */
407 if (profile->xmatch) {
408 unsigned int state, count;
409 u32 perm;
410
411 state = aa_dfa_leftmatch(profile->xmatch, DFA_START,
412 name, &count);
413 perm = dfa_user_allow(profile->xmatch, state);
414 /* any accepting state means a valid match. */
415 if (perm & MAY_EXEC) {
416 int ret;
417
418 if (count < candidate_len)
419 continue;
420
421 ret = aa_xattrs_match(bprm, profile, state);
422 /* Fail matching if the xattrs don't match */
423 if (ret < 0)
424 continue;
425
426 /*
427 * TODO: allow for more flexible best match
428 *
429 * The new match isn't more specific
430 * than the current best match
431 */
432 if (count == candidate_len &&
433 ret <= candidate_xattrs) {
434 /* Match is equivalent, so conflict */
435 if (ret == candidate_xattrs)
436 conflict = true;
437 continue;
438 }
439
440 /* Either the same length with more matching
441 * xattrs, or a longer match
442 */
443 candidate = profile;
444 candidate_len = profile->xmatch_len;
445 candidate_xattrs = ret;
446 conflict = false;
447 }
448 } else if (!strcmp(profile->base.name, name))
449 /*
450 * old exact non-re match, without conditionals such
451 * as xattrs. no more searching required
452 */
453 return profile;
454 }
455
456 if (conflict) {
457 *info = "conflicting profile attachments";
458 return NULL;
459 }
460
461 return candidate;
462}
463
464/**
465 * find_attach - do attachment search for unconfined processes
466 * @bprm - binprm structure of transitioning task
467 * @ns: the current namespace (NOT NULL)
468 * @list: list to search (NOT NULL)
469 * @name: the executable name to match against (NOT NULL)
470 * @info: info message if there was an error
471 *
472 * Returns: label or NULL if no match found
473 */
474static struct aa_label *find_attach(const struct linux_binprm *bprm,
475 struct aa_ns *ns, struct list_head *list,
476 const char *name, const char **info)
477{
478 struct aa_profile *profile;
479
480 rcu_read_lock();
481 profile = aa_get_profile(__attach_match(bprm, name, list, info));
482 rcu_read_unlock();
483
484 return profile ? &profile->label : NULL;
485}
486
487static const char *next_name(int xtype, const char *name)
488{
489 return NULL;
490}
491
492/**
493 * x_table_lookup - lookup an x transition name via transition table
494 * @profile: current profile (NOT NULL)
495 * @xindex: index into x transition table
496 * @name: returns: name tested to find label (NOT NULL)
497 *
498 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
499 */
500struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
501 const char **name)
502{
503 struct aa_label *label = NULL;
504 u32 xtype = xindex & AA_X_TYPE_MASK;
505 int index = xindex & AA_X_INDEX_MASK;
506
507 AA_BUG(!name);
508
509 /* index is guaranteed to be in range, validated at load time */
510 /* TODO: move lookup parsing to unpack time so this is a straight
511 * index into the resultant label
512 */
513 for (*name = profile->file.trans.table[index]; !label && *name;
514 *name = next_name(xtype, *name)) {
515 if (xindex & AA_X_CHILD) {
516 struct aa_profile *new_profile;
517 /* release by caller */
518 new_profile = aa_find_child(profile, *name);
519 if (new_profile)
520 label = &new_profile->label;
521 continue;
522 }
523 label = aa_label_parse(&profile->label, *name, GFP_ATOMIC,
524 true, false);
525 if (IS_ERR(label))
526 label = NULL;
527 }
528
529 /* released by caller */
530
531 return label;
532}
533
534/**
535 * x_to_label - get target label for a given xindex
536 * @profile: current profile (NOT NULL)
537 * @bprm: binprm structure of transitioning task
538 * @name: name to lookup (NOT NULL)
539 * @xindex: index into x transition table
540 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
541 *
542 * find label for a transition index
543 *
544 * Returns: refcounted label or NULL if not found available
545 */
546static struct aa_label *x_to_label(struct aa_profile *profile,
547 const struct linux_binprm *bprm,
548 const char *name, u32 xindex,
549 const char **lookupname,
550 const char **info)
551{
552 struct aa_label *new = NULL;
553 struct aa_ns *ns = profile->ns;
554 u32 xtype = xindex & AA_X_TYPE_MASK;
555 const char *stack = NULL;
556
557 switch (xtype) {
558 case AA_X_NONE:
559 /* fail exec unless ix || ux fallback - handled by caller */
560 *lookupname = NULL;
561 break;
562 case AA_X_TABLE:
563 /* TODO: fix when perm mapping done at unload */
564 stack = profile->file.trans.table[xindex & AA_X_INDEX_MASK];
565 if (*stack != '&') {
566 /* released by caller */
567 new = x_table_lookup(profile, xindex, lookupname);
568 stack = NULL;
569 break;
570 }
571 /* fall through - to X_NAME */
572 case AA_X_NAME:
573 if (xindex & AA_X_CHILD)
574 /* released by caller */
575 new = find_attach(bprm, ns, &profile->base.profiles,
576 name, info);
577 else
578 /* released by caller */
579 new = find_attach(bprm, ns, &ns->base.profiles,
580 name, info);
581 *lookupname = name;
582 break;
583 }
584
585 if (!new) {
586 if (xindex & AA_X_INHERIT) {
587 /* (p|c|n)ix - don't change profile but do
588 * use the newest version
589 */
590 *info = "ix fallback";
591 /* no profile && no error */
592 new = aa_get_newest_label(&profile->label);
593 } else if (xindex & AA_X_UNCONFINED) {
594 new = aa_get_newest_label(ns_unconfined(profile->ns));
595 *info = "ux fallback";
596 }
597 }
598
599 if (new && stack) {
600 /* base the stack on post domain transition */
601 struct aa_label *base = new;
602
603 new = aa_label_parse(base, stack, GFP_ATOMIC, true, false);
604 if (IS_ERR(new))
605 new = NULL;
606 aa_put_label(base);
607 }
608
609 /* released by caller */
610 return new;
611}
612
613static struct aa_label *profile_transition(struct aa_profile *profile,
614 const struct linux_binprm *bprm,
615 char *buffer, struct path_cond *cond,
616 bool *secure_exec)
617{
618 struct aa_label *new = NULL;
619 struct aa_profile *component;
620 struct label_it i;
621 const char *info = NULL, *name = NULL, *target = NULL;
622 unsigned int state = profile->file.start;
623 struct aa_perms perms = {};
624 bool nonewprivs = false;
625 int error = 0;
626
627 AA_BUG(!profile);
628 AA_BUG(!bprm);
629 AA_BUG(!buffer);
630
631 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
632 &name, &info, profile->disconnected);
633 if (error) {
634 if (profile_unconfined(profile) ||
635 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
636 AA_DEBUG("name lookup ix on error");
637 error = 0;
638 new = aa_get_newest_label(&profile->label);
639 }
640 name = bprm->filename;
641 goto audit;
642 }
643
644 if (profile_unconfined(profile)) {
645 new = find_attach(bprm, profile->ns,
646 &profile->ns->base.profiles, name, &info);
647 if (new) {
648 AA_DEBUG("unconfined attached to new label");
649 return new;
650 }
651 AA_DEBUG("unconfined exec no attachment");
652 return aa_get_newest_label(&profile->label);
653 }
654
655 /* find exec permissions for name */
656 state = aa_str_perms(profile->file.dfa, state, name, cond, &perms);
657 if (perms.allow & MAY_EXEC) {
658 /* exec permission determine how to transition */
659 new = x_to_label(profile, bprm, name, perms.xindex, &target,
660 &info);
661 if (new && new->proxy == profile->label.proxy && info) {
662 /* hack ix fallback - improve how this is detected */
663 goto audit;
664 } else if (!new) {
665 error = -EACCES;
666 info = "profile transition not found";
667 /* remove MAY_EXEC to audit as failure */
668 perms.allow &= ~MAY_EXEC;
669 } else {
670 /* verify that each component's xattr requirements are
671 * met, and fail execution otherwise
672 */
673 label_for_each(i, new, component) {
674 if (aa_xattrs_match(bprm, component, state) <
675 0) {
676 error = -EACCES;
677 info = "required xattrs not present";
678 perms.allow &= ~MAY_EXEC;
679 aa_put_label(new);
680 new = NULL;
681 goto audit;
682 }
683 }
684 }
685 } else if (COMPLAIN_MODE(profile)) {
686 /* no exec permission - learning mode */
687 struct aa_profile *new_profile = NULL;
688 char *n = kstrdup(name, GFP_ATOMIC);
689
690 if (n) {
691 /* name is ptr into buffer */
692 long pos = name - buffer;
693 /* break per cpu buffer hold */
694 put_buffers(buffer);
695 new_profile = aa_new_null_profile(profile, false, n,
696 GFP_KERNEL);
697 get_buffers(buffer);
698 name = buffer + pos;
699 strcpy((char *)name, n);
700 kfree(n);
701 }
702 if (!new_profile) {
703 error = -ENOMEM;
704 info = "could not create null profile";
705 } else {
706 error = -EACCES;
707 new = &new_profile->label;
708 }
709 perms.xindex |= AA_X_UNSAFE;
710 } else
711 /* fail exec */
712 error = -EACCES;
713
714 if (!new)
715 goto audit;
716
717
718 if (!(perms.xindex & AA_X_UNSAFE)) {
719 if (DEBUG_ON) {
720 dbg_printk("apparmor: scrubbing environment variables"
721 " for %s profile=", name);
722 aa_label_printk(new, GFP_ATOMIC);
723 dbg_printk("\n");
724 }
725 *secure_exec = true;
726 }
727
728audit:
729 aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
730 cond->uid, info, error);
731 if (!new || nonewprivs) {
732 aa_put_label(new);
733 return ERR_PTR(error);
734 }
735
736 return new;
737}
738
739static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
740 bool stack, const struct linux_binprm *bprm,
741 char *buffer, struct path_cond *cond,
742 bool *secure_exec)
743{
744 unsigned int state = profile->file.start;
745 struct aa_perms perms = {};
746 const char *xname = NULL, *info = "change_profile onexec";
747 int error = -EACCES;
748
749 AA_BUG(!profile);
750 AA_BUG(!onexec);
751 AA_BUG(!bprm);
752 AA_BUG(!buffer);
753
754 if (profile_unconfined(profile)) {
755 /* change_profile on exec already granted */
756 /*
757 * NOTE: Domain transitions from unconfined are allowed
758 * even when no_new_privs is set because this aways results
759 * in a further reduction of permissions.
760 */
761 return 0;
762 }
763
764 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
765 &xname, &info, profile->disconnected);
766 if (error) {
767 if (profile_unconfined(profile) ||
768 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
769 AA_DEBUG("name lookup ix on error");
770 error = 0;
771 }
772 xname = bprm->filename;
773 goto audit;
774 }
775
776 /* find exec permissions for name */
777 state = aa_str_perms(profile->file.dfa, state, xname, cond, &perms);
778 if (!(perms.allow & AA_MAY_ONEXEC)) {
779 info = "no change_onexec valid for executable";
780 goto audit;
781 }
782 /* test if this exec can be paired with change_profile onexec.
783 * onexec permission is linked to exec with a standard pairing
784 * exec\0change_profile
785 */
786 state = aa_dfa_null_transition(profile->file.dfa, state);
787 error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
788 state, &perms);
789 if (error) {
790 perms.allow &= ~AA_MAY_ONEXEC;
791 goto audit;
792 }
793
794 if (!(perms.xindex & AA_X_UNSAFE)) {
795 if (DEBUG_ON) {
796 dbg_printk("apparmor: scrubbing environment "
797 "variables for %s label=", xname);
798 aa_label_printk(onexec, GFP_ATOMIC);
799 dbg_printk("\n");
800 }
801 *secure_exec = true;
802 }
803
804audit:
805 return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
806 NULL, onexec, cond->uid, info, error);
807}
808
809/* ensure none ns domain transitions are correctly applied with onexec */
810
811static struct aa_label *handle_onexec(struct aa_label *label,
812 struct aa_label *onexec, bool stack,
813 const struct linux_binprm *bprm,
814 char *buffer, struct path_cond *cond,
815 bool *unsafe)
816{
817 struct aa_profile *profile;
818 struct aa_label *new;
819 int error;
820
821 AA_BUG(!label);
822 AA_BUG(!onexec);
823 AA_BUG(!bprm);
824 AA_BUG(!buffer);
825
826 if (!stack) {
827 error = fn_for_each_in_ns(label, profile,
828 profile_onexec(profile, onexec, stack,
829 bprm, buffer, cond, unsafe));
830 if (error)
831 return ERR_PTR(error);
832 new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
833 aa_get_newest_label(onexec),
834 profile_transition(profile, bprm, buffer,
835 cond, unsafe));
836
837 } else {
838 /* TODO: determine how much we want to loosen this */
839 error = fn_for_each_in_ns(label, profile,
840 profile_onexec(profile, onexec, stack, bprm,
841 buffer, cond, unsafe));
842 if (error)
843 return ERR_PTR(error);
844 new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
845 aa_label_merge(&profile->label, onexec,
846 GFP_ATOMIC),
847 profile_transition(profile, bprm, buffer,
848 cond, unsafe));
849 }
850
851 if (new)
852 return new;
853
854 /* TODO: get rid of GLOBAL_ROOT_UID */
855 error = fn_for_each_in_ns(label, profile,
856 aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
857 AA_MAY_ONEXEC, bprm->filename, NULL,
858 onexec, GLOBAL_ROOT_UID,
859 "failed to build target label", -ENOMEM));
860 return ERR_PTR(error);
861}
862
863/**
864 * apparmor_bprm_set_creds - set the new creds on the bprm struct
865 * @bprm: binprm for the exec (NOT NULL)
866 *
867 * Returns: %0 or error on failure
868 *
869 * TODO: once the other paths are done see if we can't refactor into a fn
870 */
871int apparmor_bprm_set_creds(struct linux_binprm *bprm)
872{
873 struct aa_task_ctx *ctx;
874 struct aa_label *label, *new = NULL;
875 struct aa_profile *profile;
876 char *buffer = NULL;
877 const char *info = NULL;
878 int error = 0;
879 bool unsafe = false;
880 struct path_cond cond = {
881 file_inode(bprm->file)->i_uid,
882 file_inode(bprm->file)->i_mode
883 };
884
885 if (bprm->called_set_creds)
886 return 0;
887
888 ctx = task_ctx(current);
889 AA_BUG(!cred_label(bprm->cred));
890 AA_BUG(!ctx);
891
892 label = aa_get_newest_label(cred_label(bprm->cred));
893
894 /*
895 * Detect no new privs being set, and store the label it
896 * occurred under. Ideally this would happen when nnp
897 * is set but there isn't a good way to do that yet.
898 *
899 * Testing for unconfined must be done before the subset test
900 */
901 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
902 !ctx->nnp)
903 ctx->nnp = aa_get_label(label);
904
905 /* buffer freed below, name is pointer into buffer */
906 get_buffers(buffer);
907 /* Test for onexec first as onexec override other x transitions. */
908 if (ctx->onexec)
909 new = handle_onexec(label, ctx->onexec, ctx->token,
910 bprm, buffer, &cond, &unsafe);
911 else
912 new = fn_label_build(label, profile, GFP_ATOMIC,
913 profile_transition(profile, bprm, buffer,
914 &cond, &unsafe));
915
916 AA_BUG(!new);
917 if (IS_ERR(new)) {
918 error = PTR_ERR(new);
919 goto done;
920 } else if (!new) {
921 error = -ENOMEM;
922 goto done;
923 }
924
925 /* Policy has specified a domain transitions. If no_new_privs and
926 * confined ensure the transition is to confinement that is subset
927 * of the confinement when the task entered no new privs.
928 *
929 * NOTE: Domain transitions from unconfined and to stacked
930 * subsets are allowed even when no_new_privs is set because this
931 * aways results in a further reduction of permissions.
932 */
933 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
934 !unconfined(label) && !aa_label_is_subset(new, ctx->nnp)) {
935 error = -EPERM;
936 info = "no new privs";
937 goto audit;
938 }
939
940 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
941 /* FIXME: currently don't mediate shared state */
942 ;
943 }
944
945 if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
946 /* TODO: test needs to be profile of label to new */
947 error = may_change_ptraced_domain(new, &info);
948 if (error)
949 goto audit;
950 }
951
952 if (unsafe) {
953 if (DEBUG_ON) {
954 dbg_printk("scrubbing environment variables for %s "
955 "label=", bprm->filename);
956 aa_label_printk(new, GFP_ATOMIC);
957 dbg_printk("\n");
958 }
959 bprm->secureexec = 1;
960 }
961
962 if (label->proxy != new->proxy) {
963 /* when transitioning clear unsafe personality bits */
964 if (DEBUG_ON) {
965 dbg_printk("apparmor: clearing unsafe personality "
966 "bits. %s label=", bprm->filename);
967 aa_label_printk(new, GFP_ATOMIC);
968 dbg_printk("\n");
969 }
970 bprm->per_clear |= PER_CLEAR_ON_SETID;
971 }
972 aa_put_label(cred_label(bprm->cred));
973 /* transfer reference, released when cred is freed */
974 set_cred_label(bprm->cred, new);
975
976done:
977 aa_put_label(label);
978 put_buffers(buffer);
979
980 return error;
981
982audit:
983 error = fn_for_each(label, profile,
984 aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
985 bprm->filename, NULL, new,
986 file_inode(bprm->file)->i_uid, info,
987 error));
988 aa_put_label(new);
989 goto done;
990}
991
992/*
993 * Functions for self directed profile change
994 */
995
996
997/* helper fn for change_hat
998 *
999 * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL
1000 */
1001static struct aa_label *build_change_hat(struct aa_profile *profile,
1002 const char *name, bool sibling)
1003{
1004 struct aa_profile *root, *hat = NULL;
1005 const char *info = NULL;
1006 int error = 0;
1007
1008 if (sibling && PROFILE_IS_HAT(profile)) {
1009 root = aa_get_profile_rcu(&profile->parent);
1010 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1011 root = aa_get_profile(profile);
1012 } else {
1013 info = "conflicting target types";
1014 error = -EPERM;
1015 goto audit;
1016 }
1017
1018 hat = aa_find_child(root, name);
1019 if (!hat) {
1020 error = -ENOENT;
1021 if (COMPLAIN_MODE(profile)) {
1022 hat = aa_new_null_profile(profile, true, name,
1023 GFP_KERNEL);
1024 if (!hat) {
1025 info = "failed null profile create";
1026 error = -ENOMEM;
1027 }
1028 }
1029 }
1030 aa_put_profile(root);
1031
1032audit:
1033 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT, AA_MAY_CHANGEHAT,
1034 name, hat ? hat->base.hname : NULL,
1035 hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1036 error);
1037 if (!hat || (error && error != -ENOENT))
1038 return ERR_PTR(error);
1039 /* if hat && error - complain mode, already audited and we adjust for
1040 * complain mode allow by returning hat->label
1041 */
1042 return &hat->label;
1043}
1044
1045/* helper fn for changing into a hat
1046 *
1047 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1048 */
1049static struct aa_label *change_hat(struct aa_label *label, const char *hats[],
1050 int count, int flags)
1051{
1052 struct aa_profile *profile, *root, *hat = NULL;
1053 struct aa_label *new;
1054 struct label_it it;
1055 bool sibling = false;
1056 const char *name, *info = NULL;
1057 int i, error;
1058
1059 AA_BUG(!label);
1060 AA_BUG(!hats);
1061 AA_BUG(count < 1);
1062
1063 if (PROFILE_IS_HAT(labels_profile(label)))
1064 sibling = true;
1065
1066 /*find first matching hat */
1067 for (i = 0; i < count && !hat; i++) {
1068 name = hats[i];
1069 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1070 if (sibling && PROFILE_IS_HAT(profile)) {
1071 root = aa_get_profile_rcu(&profile->parent);
1072 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1073 root = aa_get_profile(profile);
1074 } else { /* conflicting change type */
1075 info = "conflicting targets types";
1076 error = -EPERM;
1077 goto fail;
1078 }
1079 hat = aa_find_child(root, name);
1080 aa_put_profile(root);
1081 if (!hat) {
1082 if (!COMPLAIN_MODE(profile))
1083 goto outer_continue;
1084 /* complain mode succeed as if hat */
1085 } else if (!PROFILE_IS_HAT(hat)) {
1086 info = "target not hat";
1087 error = -EPERM;
1088 aa_put_profile(hat);
1089 goto fail;
1090 }
1091 aa_put_profile(hat);
1092 }
1093 /* found a hat for all profiles in ns */
1094 goto build;
1095outer_continue:
1096 ;
1097 }
1098 /* no hats that match, find appropriate error
1099 *
1100 * In complain mode audit of the failure is based off of the first
1101 * hat supplied. This is done due how userspace interacts with
1102 * change_hat.
1103 */
1104 name = NULL;
1105 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1106 if (!list_empty(&profile->base.profiles)) {
1107 info = "hat not found";
1108 error = -ENOENT;
1109 goto fail;
1110 }
1111 }
1112 info = "no hats defined";
1113 error = -ECHILD;
1114
1115fail:
1116 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1117 /*
1118 * no target as it has failed to be found or built
1119 *
1120 * change_hat uses probing and should not log failures
1121 * related to missing hats
1122 */
1123 /* TODO: get rid of GLOBAL_ROOT_UID */
1124 if (count > 1 || COMPLAIN_MODE(profile)) {
1125 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT,
1126 AA_MAY_CHANGEHAT, name, NULL, NULL,
1127 GLOBAL_ROOT_UID, info, error);
1128 }
1129 }
1130 return ERR_PTR(error);
1131
1132build:
1133 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1134 build_change_hat(profile, name, sibling),
1135 aa_get_label(&profile->label));
1136 if (!new) {
1137 info = "label build failed";
1138 error = -ENOMEM;
1139 goto fail;
1140 } /* else if (IS_ERR) build_change_hat has logged error so return new */
1141
1142 return new;
1143}
1144
1145/**
1146 * aa_change_hat - change hat to/from subprofile
1147 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1148 * @count: number of hat names in @hats
1149 * @token: magic value to validate the hat change
1150 * @flags: flags affecting behavior of the change
1151 *
1152 * Returns %0 on success, error otherwise.
1153 *
1154 * Change to the first profile specified in @hats that exists, and store
1155 * the @hat_magic in the current task context. If the count == 0 and the
1156 * @token matches that stored in the current task context, return to the
1157 * top level profile.
1158 *
1159 * change_hat only applies to profiles in the current ns, and each profile
1160 * in the ns must make the same transition otherwise change_hat will fail.
1161 */
1162int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1163{
1164 const struct cred *cred;
1165 struct aa_task_ctx *ctx = task_ctx(current);
1166 struct aa_label *label, *previous, *new = NULL, *target = NULL;
1167 struct aa_profile *profile;
1168 struct aa_perms perms = {};
1169 const char *info = NULL;
1170 int error = 0;
1171
1172 /* released below */
1173 cred = get_current_cred();
1174 label = aa_get_newest_cred_label(cred);
1175 previous = aa_get_newest_label(ctx->previous);
1176
1177 /*
1178 * Detect no new privs being set, and store the label it
1179 * occurred under. Ideally this would happen when nnp
1180 * is set but there isn't a good way to do that yet.
1181 *
1182 * Testing for unconfined must be done before the subset test
1183 */
1184 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1185 ctx->nnp = aa_get_label(label);
1186
1187 if (unconfined(label)) {
1188 info = "unconfined can not change_hat";
1189 error = -EPERM;
1190 goto fail;
1191 }
1192
1193 if (count) {
1194 new = change_hat(label, hats, count, flags);
1195 AA_BUG(!new);
1196 if (IS_ERR(new)) {
1197 error = PTR_ERR(new);
1198 new = NULL;
1199 /* already audited */
1200 goto out;
1201 }
1202
1203 error = may_change_ptraced_domain(new, &info);
1204 if (error)
1205 goto fail;
1206
1207 /*
1208 * no new privs prevents domain transitions that would
1209 * reduce restrictions.
1210 */
1211 if (task_no_new_privs(current) && !unconfined(label) &&
1212 !aa_label_is_subset(new, ctx->nnp)) {
1213 /* not an apparmor denial per se, so don't log it */
1214 AA_DEBUG("no_new_privs - change_hat denied");
1215 error = -EPERM;
1216 goto out;
1217 }
1218
1219 if (flags & AA_CHANGE_TEST)
1220 goto out;
1221
1222 target = new;
1223 error = aa_set_current_hat(new, token);
1224 if (error == -EACCES)
1225 /* kill task in case of brute force attacks */
1226 goto kill;
1227 } else if (previous && !(flags & AA_CHANGE_TEST)) {
1228 /*
1229 * no new privs prevents domain transitions that would
1230 * reduce restrictions.
1231 */
1232 if (task_no_new_privs(current) && !unconfined(label) &&
1233 !aa_label_is_subset(previous, ctx->nnp)) {
1234 /* not an apparmor denial per se, so don't log it */
1235 AA_DEBUG("no_new_privs - change_hat denied");
1236 error = -EPERM;
1237 goto out;
1238 }
1239
1240 /* Return to saved label. Kill task if restore fails
1241 * to avoid brute force attacks
1242 */
1243 target = previous;
1244 error = aa_restore_previous_label(token);
1245 if (error) {
1246 if (error == -EACCES)
1247 goto kill;
1248 goto fail;
1249 }
1250 } /* else ignore @flags && restores when there is no saved profile */
1251
1252out:
1253 aa_put_label(new);
1254 aa_put_label(previous);
1255 aa_put_label(label);
1256 put_cred(cred);
1257
1258 return error;
1259
1260kill:
1261 info = "failed token match";
1262 perms.kill = AA_MAY_CHANGEHAT;
1263
1264fail:
1265 fn_for_each_in_ns(label, profile,
1266 aa_audit_file(profile, &perms, OP_CHANGE_HAT,
1267 AA_MAY_CHANGEHAT, NULL, NULL, target,
1268 GLOBAL_ROOT_UID, info, error));
1269
1270 goto out;
1271}
1272
1273
1274static int change_profile_perms_wrapper(const char *op, const char *name,
1275 struct aa_profile *profile,
1276 struct aa_label *target, bool stack,
1277 u32 request, struct aa_perms *perms)
1278{
1279 const char *info = NULL;
1280 int error = 0;
1281
1282 if (!error)
1283 error = change_profile_perms(profile, target, stack, request,
1284 profile->file.start, perms);
1285 if (error)
1286 error = aa_audit_file(profile, perms, op, request, name,
1287 NULL, target, GLOBAL_ROOT_UID, info,
1288 error);
1289
1290 return error;
1291}
1292
1293/**
1294 * aa_change_profile - perform a one-way profile transition
1295 * @fqname: name of profile may include namespace (NOT NULL)
1296 * @onexec: whether this transition is to take place immediately or at exec
1297 * @flags: flags affecting change behavior
1298 *
1299 * Change to new profile @name. Unlike with hats, there is no way
1300 * to change back. If @name isn't specified the current profile name is
1301 * used.
1302 * If @onexec then the transition is delayed until
1303 * the next exec.
1304 *
1305 * Returns %0 on success, error otherwise.
1306 */
1307int aa_change_profile(const char *fqname, int flags)
1308{
1309 struct aa_label *label, *new = NULL, *target = NULL;
1310 struct aa_profile *profile;
1311 struct aa_perms perms = {};
1312 const char *info = NULL;
1313 const char *auditname = fqname; /* retain leading & if stack */
1314 bool stack = flags & AA_CHANGE_STACK;
1315 struct aa_task_ctx *ctx = task_ctx(current);
1316 int error = 0;
1317 char *op;
1318 u32 request;
1319
1320 label = aa_get_current_label();
1321
1322 /*
1323 * Detect no new privs being set, and store the label it
1324 * occurred under. Ideally this would happen when nnp
1325 * is set but there isn't a good way to do that yet.
1326 *
1327 * Testing for unconfined must be done before the subset test
1328 */
1329 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1330 ctx->nnp = aa_get_label(label);
1331
1332 if (!fqname || !*fqname) {
1333 AA_DEBUG("no profile name");
1334 return -EINVAL;
1335 }
1336
1337 if (flags & AA_CHANGE_ONEXEC) {
1338 request = AA_MAY_ONEXEC;
1339 if (stack)
1340 op = OP_STACK_ONEXEC;
1341 else
1342 op = OP_CHANGE_ONEXEC;
1343 } else {
1344 request = AA_MAY_CHANGE_PROFILE;
1345 if (stack)
1346 op = OP_STACK;
1347 else
1348 op = OP_CHANGE_PROFILE;
1349 }
1350
1351 label = aa_get_current_label();
1352
1353 if (*fqname == '&') {
1354 stack = true;
1355 /* don't have label_parse() do stacking */
1356 fqname++;
1357 }
1358 target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1359 if (IS_ERR(target)) {
1360 struct aa_profile *tprofile;
1361
1362 info = "label not found";
1363 error = PTR_ERR(target);
1364 target = NULL;
1365 /*
1366 * TODO: fixme using labels_profile is not right - do profile
1367 * per complain profile
1368 */
1369 if ((flags & AA_CHANGE_TEST) ||
1370 !COMPLAIN_MODE(labels_profile(label)))
1371 goto audit;
1372 /* released below */
1373 tprofile = aa_new_null_profile(labels_profile(label), false,
1374 fqname, GFP_KERNEL);
1375 if (!tprofile) {
1376 info = "failed null profile create";
1377 error = -ENOMEM;
1378 goto audit;
1379 }
1380 target = &tprofile->label;
1381 goto check;
1382 }
1383
1384 /*
1385 * self directed transitions only apply to current policy ns
1386 * TODO: currently requiring perms for stacking and straight change
1387 * stacking doesn't strictly need this. Determine how much
1388 * we want to loosen this restriction for stacking
1389 *
1390 * if (!stack) {
1391 */
1392 error = fn_for_each_in_ns(label, profile,
1393 change_profile_perms_wrapper(op, auditname,
1394 profile, target, stack,
1395 request, &perms));
1396 if (error)
1397 /* auditing done in change_profile_perms_wrapper */
1398 goto out;
1399
1400 /* } */
1401
1402check:
1403 /* check if tracing task is allowed to trace target domain */
1404 error = may_change_ptraced_domain(target, &info);
1405 if (error && !fn_for_each_in_ns(label, profile,
1406 COMPLAIN_MODE(profile)))
1407 goto audit;
1408
1409 /* TODO: add permission check to allow this
1410 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1411 * info = "not a single threaded task";
1412 * error = -EACCES;
1413 * goto audit;
1414 * }
1415 */
1416 if (flags & AA_CHANGE_TEST)
1417 goto out;
1418
1419 /* stacking is always a subset, so only check the nonstack case */
1420 if (!stack) {
1421 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1422 aa_get_label(target),
1423 aa_get_label(&profile->label));
1424 /*
1425 * no new privs prevents domain transitions that would
1426 * reduce restrictions.
1427 */
1428 if (task_no_new_privs(current) && !unconfined(label) &&
1429 !aa_label_is_subset(new, ctx->nnp)) {
1430 /* not an apparmor denial per se, so don't log it */
1431 AA_DEBUG("no_new_privs - change_hat denied");
1432 error = -EPERM;
1433 goto out;
1434 }
1435 }
1436
1437 if (!(flags & AA_CHANGE_ONEXEC)) {
1438 /* only transition profiles in the current ns */
1439 if (stack)
1440 new = aa_label_merge(label, target, GFP_KERNEL);
1441 if (IS_ERR_OR_NULL(new)) {
1442 info = "failed to build target label";
1443 if (!new)
1444 error = -ENOMEM;
1445 else
1446 error = PTR_ERR(new);
1447 new = NULL;
1448 perms.allow = 0;
1449 goto audit;
1450 }
1451 error = aa_replace_current_label(new);
1452 } else {
1453 if (new) {
1454 aa_put_label(new);
1455 new = NULL;
1456 }
1457
1458 /* full transition will be built in exec path */
1459 error = aa_set_current_onexec(target, stack);
1460 }
1461
1462audit:
1463 error = fn_for_each_in_ns(label, profile,
1464 aa_audit_file(profile, &perms, op, request, auditname,
1465 NULL, new ? new : target,
1466 GLOBAL_ROOT_UID, info, error));
1467
1468out:
1469 aa_put_label(new);
1470 aa_put_label(target);
1471 aa_put_label(label);
1472
1473 return error;
1474}
1/*
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 * @to_profile: profile to change to (NOT NULL)
54 *
55 * Check if current is ptraced and if so if the tracing task is allowed
56 * to trace the new domain
57 *
58 * Returns: %0 or error if change not allowed
59 */
60static int may_change_ptraced_domain(struct aa_profile *to_profile)
61{
62 struct task_struct *tracer;
63 struct aa_profile *tracerp = NULL;
64 int error = 0;
65
66 rcu_read_lock();
67 tracer = ptrace_parent(current);
68 if (tracer)
69 /* released below */
70 tracerp = aa_get_task_profile(tracer);
71
72 /* not ptraced */
73 if (!tracer || unconfined(tracerp))
74 goto out;
75
76 error = aa_may_ptrace(tracerp, to_profile, PTRACE_MODE_ATTACH);
77
78out:
79 rcu_read_unlock();
80 aa_put_profile(tracerp);
81
82 return error;
83}
84
85/**
86 * change_profile_perms - find permissions for change_profile
87 * @profile: the current profile (NOT NULL)
88 * @ns: the namespace being switched to (NOT NULL)
89 * @name: the name of the profile to change to (NOT NULL)
90 * @request: requested perms
91 * @start: state to start matching in
92 *
93 * Returns: permission set
94 */
95static struct file_perms change_profile_perms(struct aa_profile *profile,
96 struct aa_namespace *ns,
97 const char *name, u32 request,
98 unsigned int start)
99{
100 struct file_perms perms;
101 struct path_cond cond = { };
102 unsigned int state;
103
104 if (unconfined(profile)) {
105 perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
106 perms.audit = perms.quiet = perms.kill = 0;
107 return perms;
108 } else if (!profile->file.dfa) {
109 return nullperms;
110 } else if ((ns == profile->ns)) {
111 /* try matching against rules with out namespace prepended */
112 aa_str_perms(profile->file.dfa, start, name, &cond, &perms);
113 if (COMBINED_PERM_MASK(perms) & request)
114 return perms;
115 }
116
117 /* try matching with namespace name and then profile */
118 state = aa_dfa_match(profile->file.dfa, start, ns->base.name);
119 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
120 aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
121
122 return perms;
123}
124
125/**
126 * __attach_match_ - find an attachment match
127 * @name - to match against (NOT NULL)
128 * @head - profile list to walk (NOT NULL)
129 *
130 * Do a linear search on the profiles in the list. There is a matching
131 * preference where an exact match is preferred over a name which uses
132 * expressions to match, and matching expressions with the greatest
133 * xmatch_len are preferred.
134 *
135 * Requires: @head not be shared or have appropriate locks held
136 *
137 * Returns: profile or NULL if no match found
138 */
139static struct aa_profile *__attach_match(const char *name,
140 struct list_head *head)
141{
142 int len = 0;
143 struct aa_profile *profile, *candidate = NULL;
144
145 list_for_each_entry_rcu(profile, head, base.list) {
146 if (profile->flags & PFLAG_NULL)
147 continue;
148 if (profile->xmatch && profile->xmatch_len > len) {
149 unsigned int state = aa_dfa_match(profile->xmatch,
150 DFA_START, name);
151 u32 perm = dfa_user_allow(profile->xmatch, state);
152 /* any accepting state means a valid match. */
153 if (perm & MAY_EXEC) {
154 candidate = profile;
155 len = profile->xmatch_len;
156 }
157 } else if (!strcmp(profile->base.name, name))
158 /* exact non-re match, no more searching required */
159 return profile;
160 }
161
162 return candidate;
163}
164
165/**
166 * find_attach - do attachment search for unconfined processes
167 * @ns: the current namespace (NOT NULL)
168 * @list: list to search (NOT NULL)
169 * @name: the executable name to match against (NOT NULL)
170 *
171 * Returns: profile or NULL if no match found
172 */
173static struct aa_profile *find_attach(struct aa_namespace *ns,
174 struct list_head *list, const char *name)
175{
176 struct aa_profile *profile;
177
178 rcu_read_lock();
179 profile = aa_get_profile(__attach_match(name, list));
180 rcu_read_unlock();
181
182 return profile;
183}
184
185/**
186 * separate_fqname - separate the namespace and profile names
187 * @fqname: the fqname name to split (NOT NULL)
188 * @ns_name: the namespace name if it exists (NOT NULL)
189 *
190 * This is the xtable equivalent routine of aa_split_fqname. It finds the
191 * split in an xtable fqname which contains an embedded \0 instead of a :
192 * if a namespace is specified. This is done so the xtable is constant and
193 * isn't re-split on every lookup.
194 *
195 * Either the profile or namespace name may be optional but if the namespace
196 * is specified the profile name termination must be present. This results
197 * in the following possible encodings:
198 * profile_name\0
199 * :ns_name\0profile_name\0
200 * :ns_name\0\0
201 *
202 * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table
203 *
204 * Returns: profile name if it is specified else NULL
205 */
206static const char *separate_fqname(const char *fqname, const char **ns_name)
207{
208 const char *name;
209
210 if (fqname[0] == ':') {
211 /* In this case there is guaranteed to be two \0 terminators
212 * in the string. They are verified at load time by
213 * by unpack_trans_table
214 */
215 *ns_name = fqname + 1; /* skip : */
216 name = *ns_name + strlen(*ns_name) + 1;
217 if (!*name)
218 name = NULL;
219 } else {
220 *ns_name = NULL;
221 name = fqname;
222 }
223
224 return name;
225}
226
227static const char *next_name(int xtype, const char *name)
228{
229 return NULL;
230}
231
232/**
233 * x_table_lookup - lookup an x transition name via transition table
234 * @profile: current profile (NOT NULL)
235 * @xindex: index into x transition table
236 *
237 * Returns: refcounted profile, or NULL on failure (MAYBE NULL)
238 */
239static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex)
240{
241 struct aa_profile *new_profile = NULL;
242 struct aa_namespace *ns = profile->ns;
243 u32 xtype = xindex & AA_X_TYPE_MASK;
244 int index = xindex & AA_X_INDEX_MASK;
245 const char *name;
246
247 /* index is guaranteed to be in range, validated at load time */
248 for (name = profile->file.trans.table[index]; !new_profile && name;
249 name = next_name(xtype, name)) {
250 struct aa_namespace *new_ns;
251 const char *xname = NULL;
252
253 new_ns = NULL;
254 if (xindex & AA_X_CHILD) {
255 /* release by caller */
256 new_profile = aa_find_child(profile, name);
257 continue;
258 } else if (*name == ':') {
259 /* switching namespace */
260 const char *ns_name;
261 xname = name = separate_fqname(name, &ns_name);
262 if (!xname)
263 /* no name so use profile name */
264 xname = profile->base.hname;
265 if (*ns_name == '@') {
266 /* TODO: variable support */
267 ;
268 }
269 /* released below */
270 new_ns = aa_find_namespace(ns, ns_name);
271 if (!new_ns)
272 continue;
273 } else if (*name == '@') {
274 /* TODO: variable support */
275 continue;
276 } else {
277 /* basic namespace lookup */
278 xname = name;
279 }
280
281 /* released by caller */
282 new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname);
283 aa_put_namespace(new_ns);
284 }
285
286 /* released by caller */
287 return new_profile;
288}
289
290/**
291 * x_to_profile - get target profile for a given xindex
292 * @profile: current profile (NOT NULL)
293 * @name: name to lookup (NOT NULL)
294 * @xindex: index into x transition table
295 *
296 * find profile for a transition index
297 *
298 * Returns: refcounted profile or NULL if not found available
299 */
300static struct aa_profile *x_to_profile(struct aa_profile *profile,
301 const char *name, u32 xindex)
302{
303 struct aa_profile *new_profile = NULL;
304 struct aa_namespace *ns = profile->ns;
305 u32 xtype = xindex & AA_X_TYPE_MASK;
306
307 switch (xtype) {
308 case AA_X_NONE:
309 /* fail exec unless ix || ux fallback - handled by caller */
310 return NULL;
311 case AA_X_NAME:
312 if (xindex & AA_X_CHILD)
313 /* released by caller */
314 new_profile = find_attach(ns, &profile->base.profiles,
315 name);
316 else
317 /* released by caller */
318 new_profile = find_attach(ns, &ns->base.profiles,
319 name);
320 break;
321 case AA_X_TABLE:
322 /* released by caller */
323 new_profile = x_table_lookup(profile, xindex);
324 break;
325 }
326
327 /* released by caller */
328 return new_profile;
329}
330
331/**
332 * apparmor_bprm_set_creds - set the new creds on the bprm struct
333 * @bprm: binprm for the exec (NOT NULL)
334 *
335 * Returns: %0 or error on failure
336 */
337int apparmor_bprm_set_creds(struct linux_binprm *bprm)
338{
339 struct aa_task_cxt *cxt;
340 struct aa_profile *profile, *new_profile = NULL;
341 struct aa_namespace *ns;
342 char *buffer = NULL;
343 unsigned int state;
344 struct file_perms perms = {};
345 struct path_cond cond = {
346 file_inode(bprm->file)->i_uid,
347 file_inode(bprm->file)->i_mode
348 };
349 const char *name = NULL, *target = NULL, *info = NULL;
350 int error = cap_bprm_set_creds(bprm);
351 if (error)
352 return error;
353
354 if (bprm->cred_prepared)
355 return 0;
356
357 cxt = cred_cxt(bprm->cred);
358 BUG_ON(!cxt);
359
360 profile = aa_get_newest_profile(cxt->profile);
361 /*
362 * get the namespace from the replacement profile as replacement
363 * can change the namespace
364 */
365 ns = profile->ns;
366 state = profile->file.start;
367
368 /* buffer freed below, name is pointer into buffer */
369 error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer,
370 &name, &info);
371 if (error) {
372 if (unconfined(profile) ||
373 (profile->flags & PFLAG_IX_ON_NAME_ERROR))
374 error = 0;
375 name = bprm->filename;
376 goto audit;
377 }
378
379 /* Test for onexec first as onexec directives override other
380 * x transitions.
381 */
382 if (unconfined(profile)) {
383 /* unconfined task */
384 if (cxt->onexec)
385 /* change_profile on exec already been granted */
386 new_profile = aa_get_profile(cxt->onexec);
387 else
388 new_profile = find_attach(ns, &ns->base.profiles, name);
389 if (!new_profile)
390 goto cleanup;
391 /*
392 * NOTE: Domain transitions from unconfined are allowed
393 * even when no_new_privs is set because this aways results
394 * in a further reduction of permissions.
395 */
396 goto apply;
397 }
398
399 /* find exec permissions for name */
400 state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms);
401 if (cxt->onexec) {
402 struct file_perms cp;
403 info = "change_profile onexec";
404 if (!(perms.allow & AA_MAY_ONEXEC))
405 goto audit;
406
407 /* test if this exec can be paired with change_profile onexec.
408 * onexec permission is linked to exec with a standard pairing
409 * exec\0change_profile
410 */
411 state = aa_dfa_null_transition(profile->file.dfa, state);
412 cp = change_profile_perms(profile, cxt->onexec->ns,
413 cxt->onexec->base.name,
414 AA_MAY_ONEXEC, state);
415
416 if (!(cp.allow & AA_MAY_ONEXEC))
417 goto audit;
418 new_profile = aa_get_newest_profile(cxt->onexec);
419 goto apply;
420 }
421
422 if (perms.allow & MAY_EXEC) {
423 /* exec permission determine how to transition */
424 new_profile = x_to_profile(profile, name, perms.xindex);
425 if (!new_profile) {
426 if (perms.xindex & AA_X_INHERIT) {
427 /* (p|c|n)ix - don't change profile but do
428 * use the newest version, which was picked
429 * up above when getting profile
430 */
431 info = "ix fallback";
432 new_profile = aa_get_profile(profile);
433 goto x_clear;
434 } else if (perms.xindex & AA_X_UNCONFINED) {
435 new_profile = aa_get_newest_profile(ns->unconfined);
436 info = "ux fallback";
437 } else {
438 error = -ENOENT;
439 info = "profile not found";
440 /* remove MAY_EXEC to audit as failure */
441 perms.allow &= ~MAY_EXEC;
442 }
443 }
444 } else if (COMPLAIN_MODE(profile)) {
445 /* no exec permission - are we in learning mode */
446 new_profile = aa_new_null_profile(profile, 0);
447 if (!new_profile) {
448 error = -ENOMEM;
449 info = "could not create null profile";
450 } else {
451 error = -EACCES;
452 target = new_profile->base.hname;
453 }
454 perms.xindex |= AA_X_UNSAFE;
455 } else
456 /* fail exec */
457 error = -EACCES;
458
459 /*
460 * Policy has specified a domain transition, if no_new_privs then
461 * fail the exec.
462 */
463 if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) {
464 aa_put_profile(new_profile);
465 error = -EPERM;
466 goto cleanup;
467 }
468
469 if (!new_profile)
470 goto audit;
471
472 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
473 /* FIXME: currently don't mediate shared state */
474 ;
475 }
476
477 if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
478 error = may_change_ptraced_domain(new_profile);
479 if (error) {
480 aa_put_profile(new_profile);
481 goto audit;
482 }
483 }
484
485 /* Determine if secure exec is needed.
486 * Can be at this point for the following reasons:
487 * 1. unconfined switching to confined
488 * 2. confined switching to different confinement
489 * 3. confined switching to unconfined
490 *
491 * Cases 2 and 3 are marked as requiring secure exec
492 * (unless policy specified "unsafe exec")
493 *
494 * bprm->unsafe is used to cache the AA_X_UNSAFE permission
495 * to avoid having to recompute in secureexec
496 */
497 if (!(perms.xindex & AA_X_UNSAFE)) {
498 AA_DEBUG("scrubbing environment variables for %s profile=%s\n",
499 name, new_profile->base.hname);
500 bprm->unsafe |= AA_SECURE_X_NEEDED;
501 }
502apply:
503 target = new_profile->base.hname;
504 /* when transitioning profiles clear unsafe personality bits */
505 bprm->per_clear |= PER_CLEAR_ON_SETID;
506
507x_clear:
508 aa_put_profile(cxt->profile);
509 /* transfer new profile reference will be released when cxt is freed */
510 cxt->profile = new_profile;
511
512 /* clear out all temporary/transitional state from the context */
513 aa_clear_task_cxt_trans(cxt);
514
515audit:
516 error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC,
517 name, target, cond.uid, info, error);
518
519cleanup:
520 aa_put_profile(profile);
521 kfree(buffer);
522
523 return error;
524}
525
526/**
527 * apparmor_bprm_secureexec - determine if secureexec is needed
528 * @bprm: binprm for exec (NOT NULL)
529 *
530 * Returns: %1 if secureexec is needed else %0
531 */
532int apparmor_bprm_secureexec(struct linux_binprm *bprm)
533{
534 int ret = cap_bprm_secureexec(bprm);
535
536 /* the decision to use secure exec is computed in set_creds
537 * and stored in bprm->unsafe.
538 */
539 if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED))
540 ret = 1;
541
542 return ret;
543}
544
545/**
546 * apparmor_bprm_committing_creds - do task cleanup on committing new creds
547 * @bprm: binprm for the exec (NOT NULL)
548 */
549void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
550{
551 struct aa_profile *profile = __aa_current_profile();
552 struct aa_task_cxt *new_cxt = cred_cxt(bprm->cred);
553
554 /* bail out if unconfined or not changing profile */
555 if ((new_cxt->profile == profile) ||
556 (unconfined(new_cxt->profile)))
557 return;
558
559 current->pdeath_signal = 0;
560
561 /* reset soft limits and set hard limits for the new profile */
562 __aa_transition_rlimits(profile, new_cxt->profile);
563}
564
565/**
566 * apparmor_bprm_commited_cred - do cleanup after new creds committed
567 * @bprm: binprm for the exec (NOT NULL)
568 */
569void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
570{
571 /* TODO: cleanup signals - ipc mediation */
572 return;
573}
574
575/*
576 * Functions for self directed profile change
577 */
578
579/**
580 * new_compound_name - create an hname with @n2 appended to @n1
581 * @n1: base of hname (NOT NULL)
582 * @n2: name to append (NOT NULL)
583 *
584 * Returns: new name or NULL on error
585 */
586static char *new_compound_name(const char *n1, const char *n2)
587{
588 char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL);
589 if (name)
590 sprintf(name, "%s//%s", n1, n2);
591 return name;
592}
593
594/**
595 * aa_change_hat - change hat to/from subprofile
596 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
597 * @count: number of hat names in @hats
598 * @token: magic value to validate the hat change
599 * @permtest: true if this is just a permission test
600 *
601 * Change to the first profile specified in @hats that exists, and store
602 * the @hat_magic in the current task context. If the count == 0 and the
603 * @token matches that stored in the current task context, return to the
604 * top level profile.
605 *
606 * Returns %0 on success, error otherwise.
607 */
608int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
609{
610 const struct cred *cred;
611 struct aa_task_cxt *cxt;
612 struct aa_profile *profile, *previous_profile, *hat = NULL;
613 char *name = NULL;
614 int i;
615 struct file_perms perms = {};
616 const char *target = NULL, *info = NULL;
617 int error = 0;
618
619 /*
620 * Fail explicitly requested domain transitions if no_new_privs.
621 * There is no exception for unconfined as change_hat is not
622 * available.
623 */
624 if (current->no_new_privs)
625 return -EPERM;
626
627 /* released below */
628 cred = get_current_cred();
629 cxt = cred_cxt(cred);
630 profile = aa_cred_profile(cred);
631 previous_profile = cxt->previous;
632
633 if (unconfined(profile)) {
634 info = "unconfined";
635 error = -EPERM;
636 goto audit;
637 }
638
639 if (count) {
640 /* attempting to change into a new hat or switch to a sibling */
641 struct aa_profile *root;
642 if (PROFILE_IS_HAT(profile))
643 root = aa_get_profile_rcu(&profile->parent);
644 else
645 root = aa_get_profile(profile);
646
647 /* find first matching hat */
648 for (i = 0; i < count && !hat; i++)
649 /* released below */
650 hat = aa_find_child(root, hats[i]);
651 if (!hat) {
652 if (!COMPLAIN_MODE(root) || permtest) {
653 if (list_empty(&root->base.profiles))
654 error = -ECHILD;
655 else
656 error = -ENOENT;
657 aa_put_profile(root);
658 goto out;
659 }
660
661 /*
662 * In complain mode and failed to match any hats.
663 * Audit the failure is based off of the first hat
664 * supplied. This is done due how userspace
665 * interacts with change_hat.
666 *
667 * TODO: Add logging of all failed hats
668 */
669
670 /* freed below */
671 name = new_compound_name(root->base.hname, hats[0]);
672 aa_put_profile(root);
673 target = name;
674 /* released below */
675 hat = aa_new_null_profile(profile, 1);
676 if (!hat) {
677 info = "failed null profile create";
678 error = -ENOMEM;
679 goto audit;
680 }
681 } else {
682 aa_put_profile(root);
683 target = hat->base.hname;
684 if (!PROFILE_IS_HAT(hat)) {
685 info = "target not hat";
686 error = -EPERM;
687 goto audit;
688 }
689 }
690
691 error = may_change_ptraced_domain(hat);
692 if (error) {
693 info = "ptraced";
694 error = -EPERM;
695 goto audit;
696 }
697
698 if (!permtest) {
699 error = aa_set_current_hat(hat, token);
700 if (error == -EACCES)
701 /* kill task in case of brute force attacks */
702 perms.kill = AA_MAY_CHANGEHAT;
703 else if (name && !error)
704 /* reset error for learning of new hats */
705 error = -ENOENT;
706 }
707 } else if (previous_profile) {
708 /* Return to saved profile. Kill task if restore fails
709 * to avoid brute force attacks
710 */
711 target = previous_profile->base.hname;
712 error = aa_restore_previous_profile(token);
713 perms.kill = AA_MAY_CHANGEHAT;
714 } else
715 /* ignore restores when there is no saved profile */
716 goto out;
717
718audit:
719 if (!permtest)
720 error = aa_audit_file(profile, &perms, GFP_KERNEL,
721 OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL,
722 target, GLOBAL_ROOT_UID, info, error);
723
724out:
725 aa_put_profile(hat);
726 kfree(name);
727 put_cred(cred);
728
729 return error;
730}
731
732/**
733 * aa_change_profile - perform a one-way profile transition
734 * @ns_name: name of the profile namespace to change to (MAYBE NULL)
735 * @hname: name of profile to change to (MAYBE NULL)
736 * @onexec: whether this transition is to take place immediately or at exec
737 * @permtest: true if this is just a permission test
738 *
739 * Change to new profile @name. Unlike with hats, there is no way
740 * to change back. If @name isn't specified the current profile name is
741 * used.
742 * If @onexec then the transition is delayed until
743 * the next exec.
744 *
745 * Returns %0 on success, error otherwise.
746 */
747int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
748 bool permtest)
749{
750 const struct cred *cred;
751 struct aa_profile *profile, *target = NULL;
752 struct aa_namespace *ns = NULL;
753 struct file_perms perms = {};
754 const char *name = NULL, *info = NULL;
755 int op, error = 0;
756 u32 request;
757
758 if (!hname && !ns_name)
759 return -EINVAL;
760
761 if (onexec) {
762 request = AA_MAY_ONEXEC;
763 op = OP_CHANGE_ONEXEC;
764 } else {
765 request = AA_MAY_CHANGE_PROFILE;
766 op = OP_CHANGE_PROFILE;
767 }
768
769 cred = get_current_cred();
770 profile = aa_cred_profile(cred);
771
772 /*
773 * Fail explicitly requested domain transitions if no_new_privs
774 * and not unconfined.
775 * Domain transitions from unconfined are allowed even when
776 * no_new_privs is set because this aways results in a reduction
777 * of permissions.
778 */
779 if (current->no_new_privs && !unconfined(profile)) {
780 put_cred(cred);
781 return -EPERM;
782 }
783
784 if (ns_name) {
785 /* released below */
786 ns = aa_find_namespace(profile->ns, ns_name);
787 if (!ns) {
788 /* we don't create new namespace in complain mode */
789 name = ns_name;
790 info = "namespace not found";
791 error = -ENOENT;
792 goto audit;
793 }
794 } else
795 /* released below */
796 ns = aa_get_namespace(profile->ns);
797
798 /* if the name was not specified, use the name of the current profile */
799 if (!hname) {
800 if (unconfined(profile))
801 hname = ns->unconfined->base.hname;
802 else
803 hname = profile->base.hname;
804 }
805
806 perms = change_profile_perms(profile, ns, hname, request,
807 profile->file.start);
808 if (!(perms.allow & request)) {
809 error = -EACCES;
810 goto audit;
811 }
812
813 /* released below */
814 target = aa_lookup_profile(ns, hname);
815 if (!target) {
816 info = "profile not found";
817 error = -ENOENT;
818 if (permtest || !COMPLAIN_MODE(profile))
819 goto audit;
820 /* released below */
821 target = aa_new_null_profile(profile, 0);
822 if (!target) {
823 info = "failed null profile create";
824 error = -ENOMEM;
825 goto audit;
826 }
827 }
828
829 /* check if tracing task is allowed to trace target domain */
830 error = may_change_ptraced_domain(target);
831 if (error) {
832 info = "ptrace prevents transition";
833 goto audit;
834 }
835
836 if (permtest)
837 goto audit;
838
839 if (onexec)
840 error = aa_set_current_onexec(target);
841 else
842 error = aa_replace_current_profile(target);
843
844audit:
845 if (!permtest)
846 error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request,
847 name, hname, GLOBAL_ROOT_UID, info, error);
848
849 aa_put_namespace(ns);
850 aa_put_profile(target);
851 put_cred(cred);
852
853 return error;
854}