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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/fs.h>
13#include <linux/file.h>
14#include <linux/mount.h>
15#include <linux/mutex.h>
16#include <linux/syscalls.h>
17#include <linux/personality.h>
18#include <linux/xattr.h>
19#include <linux/user_namespace.h>
20
21#include "include/audit.h"
22#include "include/apparmorfs.h"
23#include "include/cred.h"
24#include "include/domain.h"
25#include "include/file.h"
26#include "include/ipc.h"
27#include "include/lib.h"
28#include "include/match.h"
29#include "include/path.h"
30#include "include/policy.h"
31#include "include/policy_ns.h"
32
33static const char * const CONFLICTING_ATTACH_STR = "conflicting profile attachments";
34static const char * const CONFLICTING_ATTACH_STR_IX =
35 "conflicting profile attachments - ix fallback";
36static const char * const CONFLICTING_ATTACH_STR_UX =
37 "conflicting profile attachments - ux fallback";
38
39/**
40 * may_change_ptraced_domain - check if can change profile on ptraced task
41 * @to_cred: cred of task changing domain
42 * @to_label: profile to change to (NOT NULL)
43 * @info: message if there is an error
44 *
45 * Check if current is ptraced and if so if the tracing task is allowed
46 * to trace the new domain
47 *
48 * Returns: %0 or error if change not allowed
49 */
50static int may_change_ptraced_domain(const struct cred *to_cred,
51 struct aa_label *to_label,
52 const char **info)
53{
54 struct task_struct *tracer;
55 struct aa_label *tracerl = NULL;
56 const struct cred *tracer_cred = NULL;
57
58 int error = 0;
59
60 rcu_read_lock();
61 tracer = ptrace_parent(current);
62 if (tracer) {
63 /* released below */
64 tracerl = aa_get_task_label(tracer);
65 tracer_cred = get_task_cred(tracer);
66 }
67 /* not ptraced */
68 if (!tracer || unconfined(tracerl))
69 goto out;
70
71 error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label,
72 PTRACE_MODE_ATTACH);
73
74out:
75 rcu_read_unlock();
76 aa_put_label(tracerl);
77 put_cred(tracer_cred);
78
79 if (error)
80 *info = "ptrace prevents transition";
81 return error;
82}
83
84/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
85 * specifically this is an exact copy of aa_label_match except
86 * aa_compute_perms is replaced with aa_compute_fperms
87 * and policy->dfa with file->dfa
88 ****/
89/* match a profile and its associated ns component if needed
90 * Assumes visibility test has already been done.
91 * If a subns profile is not to be matched should be prescreened with
92 * visibility test.
93 */
94static inline aa_state_t match_component(const struct aa_profile *profile,
95 const struct aa_profile *tp,
96 bool stack, aa_state_t state)
97{
98 struct aa_ruleset *rules = profile->label.rules[0];
99 const char *ns_name;
100
101 if (stack)
102 state = aa_dfa_match(rules->file->dfa, state, "&");
103 if (profile->ns == tp->ns)
104 return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
105
106 /* try matching with namespace name and then profile */
107 ns_name = aa_ns_name(profile->ns, tp->ns, true);
108 state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
109 state = aa_dfa_match(rules->file->dfa, state, ns_name);
110 state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
111 return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
112}
113
114/**
115 * label_compound_match - find perms for full compound label
116 * @profile: profile to find perms for
117 * @label: label to check access permissions for
118 * @stack: whether this is a stacking request
119 * @state: state to start match in
120 * @inview: whether to match labels in view or only in scope
121 * @request: permissions to request
122 * @perms: perms struct to set
123 *
124 * Returns: 0 on success else ERROR
125 *
126 * For the label A//&B//&C this does the perm match for A//&B//&C
127 * @perms should be preinitialized with allperms OR a previous permission
128 * check to be stacked.
129 */
130static int label_compound_match(const struct aa_profile *profile,
131 struct aa_label *label, bool stack,
132 aa_state_t state, bool inview, u32 request,
133 struct aa_perms *perms)
134{
135 struct aa_ruleset *rules = profile->label.rules[0];
136 struct aa_profile *tp;
137 struct label_it i;
138 struct path_cond cond = { };
139
140 /* find first subcomponent that is in view and going to be interacted with */
141 label_for_each(i, label, tp) {
142 if (!aa_ns_visible(profile->ns, tp->ns, inview))
143 continue;
144 state = match_component(profile, tp, stack, state);
145 if (!state)
146 goto fail;
147 goto next;
148 }
149
150 /* no component visible */
151 *perms = allperms;
152 return 0;
153
154next:
155 label_for_each_cont(i, label, tp) {
156 if (!aa_ns_visible(profile->ns, tp->ns, inview))
157 continue;
158 state = aa_dfa_match(rules->file->dfa, state, "//&");
159 state = match_component(profile, tp, false, state);
160 if (!state)
161 goto fail;
162 }
163 *perms = *(aa_lookup_condperms(current_fsuid(), rules->file, state,
164 &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 * @inview: whether to match labels in view or only in scope
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(const struct aa_profile *profile,
193 struct aa_label *label, bool stack,
194 aa_state_t start, bool inview, u32 request,
195 struct aa_perms *perms)
196{
197 struct aa_ruleset *rules = profile->label.rules[0];
198 struct aa_profile *tp;
199 struct label_it i;
200 struct aa_perms tmp;
201 struct path_cond cond = { };
202 aa_state_t state = 0;
203
204 /* find first subcomponent to test */
205 label_for_each(i, label, tp) {
206 if (!aa_ns_visible(profile->ns, tp->ns, inview))
207 continue;
208 state = match_component(profile, tp, stack, start);
209 if (!state)
210 goto fail;
211 goto next;
212 }
213
214 /* no subcomponents visible - no change in perms */
215 return 0;
216
217next:
218 tmp = *(aa_lookup_condperms(current_fsuid(), rules->file, state,
219 &cond));
220 aa_apply_modes_to_perms(profile, &tmp);
221 aa_perms_accum(perms, &tmp);
222 label_for_each_cont(i, label, tp) {
223 if (!aa_ns_visible(profile->ns, tp->ns, inview))
224 continue;
225 state = match_component(profile, tp, stack, start);
226 if (!state)
227 goto fail;
228 tmp = *(aa_lookup_condperms(current_fsuid(), rules->file, state,
229 &cond));
230 aa_apply_modes_to_perms(profile, &tmp);
231 aa_perms_accum(perms, &tmp);
232 }
233
234 if ((perms->allow & request) != request)
235 return -EACCES;
236
237 return 0;
238
239fail:
240 *perms = nullperms;
241 return -EACCES;
242}
243
244/**
245 * label_match - do a multi-component label match
246 * @profile: profile to match against (NOT NULL)
247 * @label: label to match (NOT NULL)
248 * @stack: whether this is a stacking request
249 * @state: state to start in
250 * @inview: whether to match labels in view or only in scope
251 * @request: permission request
252 * @perms: Returns computed perms (NOT NULL)
253 *
254 * Returns: the state the match finished in, may be the none matching state
255 */
256static int label_match(const struct aa_profile *profile, struct aa_label *label,
257 bool stack, aa_state_t state, bool inview, u32 request,
258 struct aa_perms *perms)
259{
260 int error;
261
262 *perms = nullperms;
263 error = label_compound_match(profile, label, stack, state, inview,
264 request, perms);
265 if (!error)
266 return error;
267
268 *perms = allperms;
269 return label_components_match(profile, label, stack, state, inview,
270 request, perms);
271}
272
273/******* end TODO: dedup *****/
274
275/**
276 * change_profile_perms - find permissions for change_profile
277 * @profile: the current profile (NOT NULL)
278 * @target: label to transition to (NOT NULL)
279 * @stack: whether this is a stacking request
280 * @request: requested perms
281 * @start: state to start matching in
282 * @perms: Returns computed perms (NOT NULL)
283 *
284 *
285 * Returns: permission set
286 *
287 * currently only matches full label A//&B//&C or individual components A, B, C
288 * not arbitrary combinations. Eg. A//&B, C
289 */
290static int change_profile_perms(const struct aa_profile *profile,
291 struct aa_label *target, bool stack,
292 u32 request, aa_state_t start,
293 struct aa_perms *perms)
294{
295 if (profile_unconfined(profile)) {
296 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
297 perms->audit = perms->quiet = perms->kill = 0;
298 return 0;
299 }
300
301 /* TODO: add profile in ns screening */
302 return label_match(profile, target, stack, start, true, request, perms);
303}
304
305/**
306 * aa_xattrs_match - check whether a file matches the xattrs defined in profile
307 * @path: path for file being matched (NOT NULL)
308 * @profile: profile to match against (NOT NULL)
309 * @state: state to start match in
310 *
311 * Returns: number of extended attributes that matched, or < 0 on error
312 */
313static int aa_xattrs_match(const struct path *path,
314 const struct aa_profile *profile, aa_state_t state)
315{
316 AA_BUG(!path);
317 AA_BUG(!profile);
318
319 int i;
320 struct dentry *d;
321 char *value = NULL;
322 const struct aa_attachment *attach = &profile->attach;
323 int size, value_size = 0, ret = attach->xattr_count;
324
325 if (!attach->xattr_count)
326 return 0;
327 might_sleep();
328
329 /* transition from exec match to xattr set */
330 state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
331 d = path->dentry;
332
333 for (i = 0; i < attach->xattr_count; i++) {
334 size = vfs_getxattr_alloc(&nop_mnt_idmap, d, attach->xattrs[i],
335 &value, value_size, GFP_KERNEL);
336 if (size >= 0) {
337 struct aa_perms *perms;
338
339 /*
340 * Check the xattr presence before value. This ensure
341 * that not present xattr can be distinguished from a 0
342 * length value or rule that matches any value
343 */
344 state = aa_dfa_null_transition(attach->xmatch->dfa,
345 state);
346 /* Check xattr value */
347 state = aa_dfa_match_len(attach->xmatch->dfa, state,
348 value, size);
349 perms = aa_lookup_perms(attach->xmatch, state);
350 if (!(perms->allow & MAY_EXEC)) {
351 ret = -EINVAL;
352 goto out;
353 }
354 }
355 /* transition to next element */
356 state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
357 if (size < 0) {
358 /*
359 * No xattr match, so verify if transition to
360 * next element was valid. IFF so the xattr
361 * was optional.
362 */
363 if (!state) {
364 ret = -EINVAL;
365 goto out;
366 }
367 /* don't count missing optional xattr as matched */
368 ret--;
369 }
370 }
371
372out:
373 kfree(value);
374 return ret;
375}
376
377/**
378 * find_attach - do attachment search for unconfined processes
379 * @path: path of file in question (NOT NULL)
380 * @ns: the current namespace (NOT NULL)
381 * @head: profile list to walk (NOT NULL)
382 * @name: to match against (NOT NULL)
383 * @info: info message if there was an error (NOT NULL)
384 *
385 * Do a linear search on the profiles in the list. There is a matching
386 * preference where an exact match is preferred over a name which uses
387 * expressions to match, and matching expressions with the greatest
388 * xmatch_len are preferred.
389 *
390 * Requires: @head not be shared or have appropriate locks held
391 *
392 * Returns: label or NULL if no match found
393 */
394static struct aa_label *find_attach(const struct path *path,
395 struct aa_ns *ns, struct list_head *head,
396 const char *name, const char **info)
397{
398 int candidate_len = 0, candidate_xattrs = 0;
399 bool conflict = false;
400 struct aa_profile *profile, *candidate = NULL;
401
402 AA_BUG(!path);
403 AA_BUG(!name);
404 AA_BUG(!head);
405
406 rcu_read_lock();
407restart:
408 list_for_each_entry_rcu(profile, head, base.list) {
409 struct aa_attachment *attach = &profile->attach;
410
411 if (profile->label.flags & FLAG_NULL &&
412 &profile->label == ns_unconfined(profile->ns))
413 continue;
414
415 /* Find the "best" matching profile. Profiles must
416 * match the path and extended attributes (if any)
417 * associated with the file. A more specific path
418 * match will be preferred over a less specific one,
419 * and a match with more matching extended attributes
420 * will be preferred over one with fewer. If the best
421 * match has both the same level of path specificity
422 * and the same number of matching extended attributes
423 * as another profile, signal a conflict and refuse to
424 * match.
425 */
426 if (attach->xmatch->dfa) {
427 unsigned int count;
428 aa_state_t state;
429 struct aa_perms *perms;
430
431 state = aa_dfa_leftmatch(attach->xmatch->dfa,
432 attach->xmatch->start[AA_CLASS_XMATCH],
433 name, &count);
434 perms = aa_lookup_perms(attach->xmatch, state);
435 /* any accepting state means a valid match. */
436 if (perms->allow & MAY_EXEC) {
437 int ret = 0;
438
439 if (count < candidate_len)
440 continue;
441
442 if (attach->xattr_count) {
443 long rev = READ_ONCE(ns->revision);
444
445 if (!aa_get_profile_not0(profile))
446 goto restart;
447 rcu_read_unlock();
448 ret = aa_xattrs_match(path, profile,
449 state);
450 rcu_read_lock();
451 aa_put_profile(profile);
452 if (rev !=
453 READ_ONCE(ns->revision))
454 /* policy changed */
455 goto restart;
456 /*
457 * Fail matching if the xattrs don't
458 * match
459 */
460 if (ret < 0)
461 continue;
462 }
463 /*
464 * TODO: allow for more flexible best match
465 *
466 * The new match isn't more specific
467 * than the current best match
468 */
469 if (count == candidate_len &&
470 ret <= candidate_xattrs) {
471 /* Match is equivalent, so conflict */
472 if (ret == candidate_xattrs)
473 conflict = true;
474 continue;
475 }
476
477 /* Either the same length with more matching
478 * xattrs, or a longer match
479 */
480 candidate = profile;
481 candidate_len = max(count, attach->xmatch_len);
482 candidate_xattrs = ret;
483 conflict = false;
484 }
485 } else if (!strcmp(profile->base.name, name)) {
486 /*
487 * old exact non-re match, without conditionals such
488 * as xattrs. no more searching required
489 */
490 candidate = profile;
491 goto out;
492 }
493 }
494
495 if (!candidate || conflict) {
496 if (conflict)
497 *info = CONFLICTING_ATTACH_STR;
498 rcu_read_unlock();
499 return NULL;
500 }
501
502out:
503 candidate = aa_get_newest_profile(candidate);
504 rcu_read_unlock();
505
506 return &candidate->label;
507}
508
509static const char *next_name(int xtype, const char *name)
510{
511 return NULL;
512}
513
514/**
515 * x_table_lookup - lookup an x transition name via transition table
516 * @profile: current profile (NOT NULL)
517 * @xindex: index into x transition table
518 * @name: returns: name tested to find label (NOT NULL)
519 *
520 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
521 * @name will always be set with the last name tried
522 */
523struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
524 const char **name)
525{
526 struct aa_ruleset *rules = profile->label.rules[0];
527 struct aa_label *label = NULL;
528 u32 xtype = xindex & AA_X_TYPE_MASK;
529 int index = xindex & AA_X_INDEX_MASK;
530 const char *next;
531
532 AA_BUG(!name);
533
534 /* index is guaranteed to be in range, validated at load time */
535 /* TODO: move lookup parsing to unpack time so this is a straight
536 * index into the resultant label
537 */
538 for (next = rules->file->trans.table[index].strs; next;
539 next = next_name(xtype, next)) {
540 const char *lookup = (*next == '&') ? next + 1 : next;
541 *name = next;
542 if (xindex & AA_X_CHILD) {
543 /* TODO: switich to parse to get stack of child */
544 struct aa_profile *new = aa_find_child(profile, lookup);
545
546 if (new)
547 /* release by caller */
548 return &new->label;
549 continue;
550 }
551 label = aa_label_parse(&profile->label, lookup, GFP_KERNEL,
552 true, false);
553 if (!IS_ERR_OR_NULL(label))
554 /* release by caller */
555 return label;
556 }
557
558 return NULL;
559}
560
561/**
562 * x_to_label - get target label for a given xindex
563 * @profile: current profile (NOT NULL)
564 * @path: path of file in question
565 * @name: name to lookup (NOT NULL)
566 * @xindex: index into x transition table
567 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
568 * @info: info message if there was an error (NOT NULL)
569 *
570 * find label for a transition index
571 *
572 * Returns: refcounted label or NULL if not found available
573 */
574static struct aa_label *x_to_label(struct aa_profile *profile,
575 const struct path *path,
576 const char *name, u32 xindex,
577 const char **lookupname,
578 const char **info)
579{
580 struct aa_label *new = NULL;
581 struct aa_label *stack = NULL;
582 struct aa_ns *ns = profile->ns;
583 u32 xtype = xindex & AA_X_TYPE_MASK;
584 /* Used for info checks during fallback handling */
585 const char *old_info = NULL;
586
587 switch (xtype) {
588 case AA_X_NONE:
589 /* fail exec unless ix || ux fallback - handled by caller */
590 *lookupname = NULL;
591 break;
592 case AA_X_TABLE:
593 /* TODO: fix when perm mapping done at unload */
594 /* released by caller
595 * if null for both stack and direct want to try fallback
596 */
597 new = x_table_lookup(profile, xindex, lookupname);
598 if (!new || **lookupname != '&')
599 break;
600 stack = new;
601 new = NULL;
602 fallthrough; /* to X_NAME */
603 case AA_X_NAME:
604 if (xindex & AA_X_CHILD)
605 /* released by caller */
606 new = find_attach(path, ns, &profile->base.profiles,
607 name, info);
608 else
609 /* released by caller */
610 new = find_attach(path, ns, &ns->base.profiles,
611 name, info);
612 *lookupname = name;
613 break;
614 }
615
616 /* fallback transition check */
617 if (!new) {
618 if (xindex & AA_X_INHERIT) {
619 /* (p|c|n)ix - don't change profile but do
620 * use the newest version
621 */
622 if (*info == CONFLICTING_ATTACH_STR) {
623 *info = CONFLICTING_ATTACH_STR_IX;
624 } else {
625 old_info = *info;
626 *info = "ix fallback";
627 }
628 /* no profile && no error */
629 new = aa_get_newest_label(&profile->label);
630 } else if (xindex & AA_X_UNCONFINED) {
631 new = aa_get_newest_label(ns_unconfined(profile->ns));
632 if (*info == CONFLICTING_ATTACH_STR) {
633 *info = CONFLICTING_ATTACH_STR_UX;
634 } else {
635 old_info = *info;
636 *info = "ux fallback";
637 }
638 }
639 /* We set old_info on the code paths above where overwriting
640 * could have happened, so now check if info was set by
641 * find_attach as well (i.e. whether we actually overwrote)
642 * and warn accordingly.
643 */
644 if (old_info && old_info != CONFLICTING_ATTACH_STR) {
645 pr_warn_ratelimited(
646 "AppArmor: find_attach (from profile %s) audit info \"%s\" dropped",
647 profile->base.hname, old_info);
648 }
649 }
650
651 if (new && stack) {
652 /* base the stack on post domain transition */
653 struct aa_label *base = new;
654
655 new = aa_label_merge(base, stack, GFP_KERNEL);
656 /* null on error */
657 aa_put_label(base);
658 }
659
660 aa_put_label(stack);
661 /* released by caller */
662 return new;
663}
664
665static struct aa_label *profile_transition(const struct cred *subj_cred,
666 struct aa_profile *profile,
667 const struct linux_binprm *bprm,
668 char *buffer, struct path_cond *cond,
669 bool *secure_exec)
670{
671 struct aa_ruleset *rules = profile->label.rules[0];
672 struct aa_label *new = NULL;
673 struct aa_profile *new_profile = NULL;
674 const char *info = NULL, *name = NULL, *target = NULL;
675 aa_state_t state = rules->file->start[AA_CLASS_FILE];
676 struct aa_perms perms = {};
677 bool nonewprivs = false;
678 int error = 0;
679
680 AA_BUG(!profile);
681 AA_BUG(!bprm);
682 AA_BUG(!buffer);
683
684 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
685 &name, &info, profile->disconnected);
686 if (error) {
687 if (profile_unconfined(profile) ||
688 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
689 AA_DEBUG(DEBUG_DOMAIN, "name lookup ix on error");
690 error = 0;
691 new = aa_get_newest_label(&profile->label);
692 }
693 name = bprm->filename;
694 goto audit;
695 }
696
697 if (profile_unconfined(profile)) {
698 new = find_attach(&bprm->file->f_path, profile->ns,
699 &profile->ns->base.profiles, name, &info);
700 /* info set -> something unusual that we should report
701 * Currently this is only conflicting attachments, but other
702 * infos added in the future should also be logged by default
703 * and only excluded on a case-by-case basis
704 */
705 if (info) {
706 /* Because perms is never used again after this audit
707 * we don't need to care about clobbering it
708 */
709 perms.audit |= MAY_EXEC;
710 perms.allow |= MAY_EXEC;
711 /* Don't cause error if auditing fails */
712 (void) aa_audit_file(subj_cred, profile, &perms,
713 OP_EXEC, MAY_EXEC, name, target, new, cond->uid,
714 info, error);
715 }
716 if (new) {
717 AA_DEBUG(DEBUG_DOMAIN, "unconfined attached to new label");
718 return new;
719 }
720 AA_DEBUG(DEBUG_DOMAIN, "unconfined exec no attachment");
721 return aa_get_newest_label(&profile->label);
722 }
723
724 /* find exec permissions for name */
725 state = aa_str_perms(rules->file, state, name, cond, &perms);
726 if (perms.allow & MAY_EXEC) {
727 /* exec permission determine how to transition */
728 new = x_to_label(profile, &bprm->file->f_path, name,
729 perms.xindex, &target, &info);
730 if (new && new->proxy == profile->label.proxy && info) {
731 /* Force audit on conflicting attachment fallback
732 * Because perms is never used again after this audit
733 * we don't need to care about clobbering it
734 */
735 if (info == CONFLICTING_ATTACH_STR_IX
736 || info == CONFLICTING_ATTACH_STR_UX)
737 perms.audit |= MAY_EXEC;
738 /* hack ix fallback - improve how this is detected */
739 goto audit;
740 } else if (!new) {
741 if (info) {
742 pr_warn_ratelimited(
743 "AppArmor: %s (from profile %s) audit info \"%s\" dropped on missing transition",
744 __func__, profile->base.hname, info);
745 }
746 info = "profile transition not found";
747 /* remove MAY_EXEC to audit as failure or complaint */
748 perms.allow &= ~MAY_EXEC;
749 if (COMPLAIN_MODE(profile)) {
750 /* create null profile instead of failing */
751 goto create_learning_profile;
752 }
753 error = -EACCES;
754 }
755 } else if (COMPLAIN_MODE(profile)) {
756create_learning_profile:
757 /* no exec permission - learning mode */
758 new_profile = aa_new_learning_profile(profile, false, name,
759 GFP_KERNEL);
760 if (!new_profile) {
761 error = -ENOMEM;
762 info = "could not create null profile";
763 } else {
764 error = -EACCES;
765 new = &new_profile->label;
766 }
767 perms.xindex |= AA_X_UNSAFE;
768 } else
769 /* fail exec */
770 error = -EACCES;
771
772 if (!new)
773 goto audit;
774
775
776 if (!(perms.xindex & AA_X_UNSAFE)) {
777 if (DEBUG_ON) {
778 dbg_printk("apparmor: setting AT_SECURE for %s profile=",
779 name);
780 aa_label_printk(new, GFP_KERNEL);
781 dbg_printk("\n");
782 }
783 *secure_exec = true;
784 }
785
786audit:
787 aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name,
788 target, new,
789 cond->uid, info, error);
790 if (!new || nonewprivs) {
791 aa_put_label(new);
792 return ERR_PTR(error);
793 }
794
795 return new;
796}
797
798static int profile_onexec(const struct cred *subj_cred,
799 struct aa_profile *profile, struct aa_label *onexec,
800 bool stack, const struct linux_binprm *bprm,
801 char *buffer, struct path_cond *cond,
802 bool *secure_exec)
803{
804 struct aa_ruleset *rules = profile->label.rules[0];
805 aa_state_t state = rules->file->start[AA_CLASS_FILE];
806 struct aa_perms perms = {};
807 const char *xname = NULL, *info = "change_profile onexec";
808 int error = -EACCES;
809
810 AA_BUG(!profile);
811 AA_BUG(!onexec);
812 AA_BUG(!bprm);
813 AA_BUG(!buffer);
814
815 if (profile_unconfined(profile)) {
816 /* change_profile on exec already granted */
817 /*
818 * NOTE: Domain transitions from unconfined are allowed
819 * even when no_new_privs is set because this always results
820 * in a further reduction of permissions.
821 */
822 return 0;
823 }
824
825 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
826 &xname, &info, profile->disconnected);
827 if (error) {
828 if (profile_unconfined(profile) ||
829 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
830 AA_DEBUG(DEBUG_DOMAIN, "name lookup ix on error");
831 error = 0;
832 }
833 xname = bprm->filename;
834 goto audit;
835 }
836
837 /* find exec permissions for name */
838 state = aa_str_perms(rules->file, state, xname, cond, &perms);
839 if (!(perms.allow & AA_MAY_ONEXEC)) {
840 info = "no change_onexec valid for executable";
841 goto audit;
842 }
843 /* test if this exec can be paired with change_profile onexec.
844 * onexec permission is linked to exec with a standard pairing
845 * exec\0change_profile
846 */
847 state = aa_dfa_null_transition(rules->file->dfa, state);
848 error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
849 state, &perms);
850 if (error) {
851 perms.allow &= ~AA_MAY_ONEXEC;
852 goto audit;
853 }
854
855 if (!(perms.xindex & AA_X_UNSAFE)) {
856 if (DEBUG_ON) {
857 dbg_printk("apparmor: setting AT_SECURE for %s label=",
858 xname);
859 aa_label_printk(onexec, GFP_KERNEL);
860 dbg_printk("\n");
861 }
862 *secure_exec = true;
863 }
864
865audit:
866 return aa_audit_file(subj_cred, profile, &perms, OP_EXEC,
867 AA_MAY_ONEXEC, xname,
868 NULL, onexec, cond->uid, info, error);
869}
870
871/* ensure none ns domain transitions are correctly applied with onexec */
872static struct aa_label *label_merge_wrap(struct aa_label *a, struct aa_label *b,
873 gfp_t gfp)
874{
875 struct aa_label *label = aa_label_merge(a, b, gfp);
876
877 if (!label)
878 return ERR_PTR(-ENOMEM);
879 return label;
880}
881
882static bool is_profile_priv_restricted_to_stack(const struct cred *subj_cred,
883 struct aa_profile *profile)
884{
885 if (profile_unconfined(profile) && profile == profile->ns->unconfined &&
886 aa_unprivileged_unconfined_restricted &&
887 /* cap_capable returns false (0) if true, hence true here means
888 * doesn't have capability and the stack will be restricted
889 */
890 cap_capable(current_cred(), &init_user_ns, CAP_MAC_OVERRIDE,
891 CAP_OPT_NOAUDIT))
892 return true;
893 return false;
894}
895
896static const char *stack_msg = "change_profile unprivileged unconfined converted to stacking";
897
898static struct aa_label *priv_restricted_transition(const struct cred *subj_cred,
899 struct aa_profile *profile,
900 const char *op, u32 request,
901 const char *name,
902 struct aa_label *transition,
903 gfp_t gfp)
904{
905 if (!is_profile_priv_restricted_to_stack(subj_cred, profile))
906 return aa_get_newest_label(transition);
907
908 /* transition allowed but only via stack */
909 struct aa_label *target = label_merge_wrap(&profile->label,
910 transition, gfp);
911 if (IS_ERR_OR_NULL(target))
912 return target;
913
914 /* doing this here is less than optimal but good enough until the
915 * fs mediation rework lands
916 */
917 struct aa_perms perms = {
918 .allow = request,
919 .audit = request,
920 };
921 aa_audit_file(subj_cred, profile, &perms, op,
922 request, name, NULL, target,
923 subj_cred->euid, stack_msg, 0);
924
925 return target;
926}
927
928static struct aa_label *handle_onexec(const struct cred *subj_cred,
929 struct aa_label *label,
930 struct aa_label *onexec, bool stack,
931 const struct linux_binprm *bprm,
932 char *buffer, struct path_cond *cond,
933 bool *unsafe)
934{
935 struct aa_profile *profile;
936 struct aa_label *new;
937 int error;
938
939 AA_BUG(!label);
940 AA_BUG(!onexec);
941 AA_BUG(!bprm);
942 AA_BUG(!buffer);
943
944 /* TODO: determine how much we want to loosen this
945 * only check profiles in scope for permission to change at exec
946 */
947 error = fn_for_each_in_scope(label, profile,
948 profile_onexec(subj_cred, profile, onexec, stack,
949 bprm, buffer, cond, unsafe));
950 if (error)
951 return ERR_PTR(error);
952
953 new = fn_label_build_in_scope(label, profile, GFP_KERNEL,
954 stack ? label_merge_wrap(&profile->label, onexec,
955 GFP_KERNEL)
956 : priv_restricted_transition(subj_cred, profile,
957 OP_CHANGE_ONEXEC, AA_MAY_ONEXEC,
958 bprm->filename, onexec,
959 GFP_KERNEL),
960 profile_transition(subj_cred, profile, bprm,
961 buffer, cond, unsafe));
962 AA_BUG(!new);
963 if (!IS_ERR(new))
964 return new;
965
966 /* TODO: get rid of GLOBAL_ROOT_UID */
967 error = fn_for_each_in_scope(label, profile,
968 aa_audit_file(subj_cred, profile, &nullperms,
969 OP_CHANGE_ONEXEC,
970 AA_MAY_ONEXEC, bprm->filename, NULL,
971 onexec, GLOBAL_ROOT_UID,
972 "failed to build target label",
973 PTR_ERR(new)));
974 return ERR_PTR(error);
975}
976
977/**
978 * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
979 * @bprm: binprm for the exec (NOT NULL)
980 *
981 * Returns: %0 or error on failure
982 *
983 * TODO: once the other paths are done see if we can't refactor into a fn
984 */
985int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
986{
987 struct aa_task_ctx *ctx;
988 struct aa_label *label, *new = NULL;
989 const struct cred *subj_cred;
990 struct aa_profile *profile;
991 char *buffer = NULL;
992 const char *info = NULL;
993 int error = 0;
994 bool unsafe = false;
995 vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(bprm->file),
996 file_inode(bprm->file));
997 struct path_cond cond = {
998 vfsuid_into_kuid(vfsuid),
999 file_inode(bprm->file)->i_mode
1000 };
1001
1002 subj_cred = current_cred();
1003 ctx = task_ctx(current);
1004 AA_BUG(!cred_label(bprm->cred));
1005 AA_BUG(!ctx);
1006
1007 label = aa_get_newest_label(cred_label(bprm->cred));
1008
1009 /*
1010 * Detect no new privs being set, and store the label it
1011 * occurred under. Ideally this would happen when nnp
1012 * is set but there isn't a good way to do that yet.
1013 *
1014 * Testing for unconfined must be done before the subset test
1015 */
1016 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
1017 !ctx->nnp)
1018 ctx->nnp = aa_get_label(label);
1019
1020 /* buffer freed below, name is pointer into buffer */
1021 buffer = aa_get_buffer(false);
1022 if (!buffer) {
1023 error = -ENOMEM;
1024 goto done;
1025 }
1026
1027 /* Test for onexec first as onexec override other x transitions. */
1028 if (ctx->onexec)
1029 new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token,
1030 bprm, buffer, &cond, &unsafe);
1031 else
1032 new = fn_label_build(label, profile, GFP_KERNEL,
1033 profile_transition(subj_cred, profile, bprm,
1034 buffer,
1035 &cond, &unsafe));
1036 AA_BUG(!new);
1037 if (IS_ERR(new)) {
1038 error = PTR_ERR(new);
1039 goto done;
1040 }
1041
1042 /* Policy has specified a domain transitions. If no_new_privs and
1043 * confined ensure the transition is to confinement that is subset
1044 * of the confinement when the task entered no new privs.
1045 *
1046 * NOTE: Domain transitions from unconfined and to stacked
1047 * subsets are allowed even when no_new_privs is set because this
1048 * always results in a further reduction of permissions.
1049 */
1050 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
1051 !unconfined(label) &&
1052 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1053 error = -EPERM;
1054 info = "no new privs";
1055 goto audit;
1056 }
1057
1058 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
1059 /* FIXME: currently don't mediate shared state */
1060 ;
1061 }
1062
1063 if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
1064 /* TODO: test needs to be profile of label to new */
1065 error = may_change_ptraced_domain(bprm->cred, new, &info);
1066 if (error)
1067 goto audit;
1068 }
1069
1070 if (unsafe) {
1071 if (DEBUG_ON) {
1072 dbg_printk("setting AT_SECURE for %s label=",
1073 bprm->filename);
1074 aa_label_printk(new, GFP_KERNEL);
1075 dbg_printk("\n");
1076 }
1077 bprm->secureexec = 1;
1078 }
1079
1080 if (label->proxy != new->proxy) {
1081 /* when transitioning clear unsafe personality bits */
1082 if (DEBUG_ON) {
1083 dbg_printk("apparmor: clearing unsafe personality bits. %s label=",
1084 bprm->filename);
1085 aa_label_printk(new, GFP_KERNEL);
1086 dbg_printk("\n");
1087 }
1088 bprm->per_clear |= PER_CLEAR_ON_SETID;
1089 }
1090 aa_put_label(cred_label(bprm->cred));
1091 /* transfer reference, released when cred is freed */
1092 set_cred_label(bprm->cred, new);
1093
1094done:
1095 aa_put_label(label);
1096 aa_put_buffer(buffer);
1097
1098 return error;
1099
1100audit:
1101 error = fn_for_each(label, profile,
1102 aa_audit_file(current_cred(), profile, &nullperms,
1103 OP_EXEC, MAY_EXEC,
1104 bprm->filename, NULL, new,
1105 vfsuid_into_kuid(vfsuid), info, error));
1106 aa_put_label(new);
1107 goto done;
1108}
1109
1110/*
1111 * Functions for self directed profile change
1112 */
1113
1114
1115/* helper fn for change_hat
1116 *
1117 * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL
1118 */
1119static struct aa_label *build_change_hat(const struct cred *subj_cred,
1120 struct aa_profile *profile,
1121 const char *name, bool sibling)
1122{
1123 struct aa_profile *root, *hat = NULL;
1124 const char *info = NULL;
1125 int error = 0;
1126
1127 if (sibling && PROFILE_IS_HAT(profile)) {
1128 root = aa_get_profile_rcu(&profile->parent);
1129 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1130 root = aa_get_profile(profile);
1131 } else {
1132 info = "conflicting target types";
1133 error = -EPERM;
1134 goto audit;
1135 }
1136
1137 hat = aa_find_child(root, name);
1138 if (!hat) {
1139 error = -ENOENT;
1140 if (COMPLAIN_MODE(profile)) {
1141 hat = __aa_new_learning_profile(profile, true, name,
1142 GFP_KERNEL);
1143 if (!hat) {
1144 info = "failed null profile create";
1145 error = -ENOMEM;
1146 }
1147 }
1148 }
1149 aa_put_profile(root);
1150
1151audit:
1152 aa_audit_file(subj_cred, profile, &nullperms, OP_CHANGE_HAT,
1153 AA_MAY_CHANGEHAT,
1154 name, hat ? hat->base.hname : NULL,
1155 hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1156 error);
1157 if (!hat || (error && error != -ENOENT))
1158 return ERR_PTR(error);
1159 /* if hat && error - complain mode, already audited and we adjust for
1160 * complain mode allow by returning hat->label
1161 */
1162 return &hat->label;
1163}
1164
1165/* helper fn for changing into a hat
1166 *
1167 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1168 */
1169static struct aa_label *change_hat(const struct cred *subj_cred,
1170 struct aa_label *label, const char *hats[],
1171 int count, int flags)
1172{
1173 struct aa_profile *profile, *root, *hat = NULL;
1174 struct aa_ns *ns, *new_ns;
1175 struct aa_label *new;
1176 struct label_it it;
1177 bool sibling = false;
1178 const char *name, *info = NULL;
1179 int i, error;
1180 bool needput = false;
1181
1182 AA_BUG(!label);
1183 AA_BUG(!hats);
1184 AA_BUG(count < 1);
1185
1186 /*
1187 * Acquire the newest label and then hold the lock until we choose a
1188 * hat, so that profile replacement doesn't atomically truncate the
1189 * list of potential hats. Because we are getting the namespaces from
1190 * the profiles and label, we can rely on the namespaces being live
1191 * and avoid incrementing their refcounts while grabbing the lock.
1192 */
1193 ns = labels_ns(label);
1194
1195retry:
1196 mutex_lock_nested(&ns->lock, ns->level);
1197 if (label_is_stale(label)) {
1198 new = aa_get_newest_label(label);
1199 new_ns = labels_ns(new);
1200
1201 if (needput)
1202 /* aa_put_label() is safe to call when under lock */
1203 aa_put_label(label);
1204 label = new;
1205 needput = true;
1206 /* check if replaced with label in parent ns, and lock there */
1207 if (new_ns != ns) {
1208 mutex_unlock(&ns->lock);
1209 ns = new_ns;
1210 /* retry will bottom out at the root of the tree */
1211 goto retry;
1212 }
1213 }
1214
1215 if (PROFILE_IS_HAT(labels_profile(label)))
1216 sibling = true;
1217
1218 /*find first matching hat */
1219 for (i = 0; i < count && !hat; i++) {
1220 name = hats[i];
1221 label_for_each_in_scope(it, labels_ns(label), label, profile) {
1222 if (sibling && PROFILE_IS_HAT(profile)) {
1223 root = aa_get_profile(rcu_dereference_protected(profile->parent,
1224 mutex_is_locked(&ns->lock)));
1225 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1226 root = aa_get_profile(profile);
1227 } else { /* conflicting change type */
1228 info = "conflicting targets types";
1229 error = -EPERM;
1230 goto fail;
1231 }
1232 hat = aa_find_child(root, name);
1233 aa_put_profile(root);
1234 if (!hat) {
1235 if (!COMPLAIN_MODE(profile))
1236 goto outer_continue;
1237 /* complain mode succeed as if hat */
1238 } else if (!PROFILE_IS_HAT(hat)) {
1239 info = "target not hat";
1240 error = -EPERM;
1241 aa_put_profile(hat);
1242 goto fail;
1243 }
1244 aa_put_profile(hat);
1245 }
1246 /* found a hat for all profiles in ns */
1247 goto build;
1248outer_continue:
1249 ;
1250 }
1251 /* no hats that match, find appropriate error
1252 *
1253 * In complain mode audit of the failure is based off of the first
1254 * hat supplied. This is done due how userspace interacts with
1255 * change_hat.
1256 */
1257 name = NULL;
1258 label_for_each_in_scope(it, labels_ns(label), label, profile) {
1259 if (!list_empty(&profile->base.profiles)) {
1260 info = "hat not found";
1261 error = -ENOENT;
1262 goto fail;
1263 }
1264 }
1265 info = "no hats defined";
1266 error = -ECHILD;
1267
1268fail:
1269 label_for_each_in_scope(it, labels_ns(label), label, profile) {
1270 /*
1271 * no target as it has failed to be found or built
1272 *
1273 * change_hat uses probing and should not log failures
1274 * related to missing hats
1275 */
1276 /* TODO: get rid of GLOBAL_ROOT_UID */
1277 if (count > 1 || COMPLAIN_MODE(profile)) {
1278 aa_audit_file(subj_cred, profile, &nullperms,
1279 OP_CHANGE_HAT,
1280 AA_MAY_CHANGEHAT, name, NULL, NULL,
1281 GLOBAL_ROOT_UID, info, error);
1282 }
1283 }
1284 mutex_unlock(&ns->lock);
1285 if (needput)
1286 aa_put_label(label);
1287 return ERR_PTR(error);
1288
1289build:
1290 new = fn_label_build_in_scope(label, profile, GFP_KERNEL,
1291 build_change_hat(subj_cred, profile, name,
1292 sibling),
1293 aa_get_label(&profile->label));
1294 mutex_unlock(&ns->lock);
1295 AA_BUG(!new);
1296 /* return new label or error ptr */
1297 if (needput)
1298 aa_put_label(label);
1299 return new;
1300}
1301
1302/**
1303 * aa_change_hat - change hat to/from subprofile
1304 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1305 * @count: number of hat names in @hats
1306 * @token: magic value to validate the hat change
1307 * @flags: flags affecting behavior of the change
1308 *
1309 * Returns %0 on success, error otherwise.
1310 *
1311 * Change to the first profile specified in @hats that exists, and store
1312 * the @hat_magic in the current task context. If the count == 0 and the
1313 * @token matches that stored in the current task context, return to the
1314 * top level profile.
1315 *
1316 * change_hat only applies to profiles in the current ns, and each profile
1317 * in the ns must make the same transition otherwise change_hat will fail.
1318 */
1319int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1320{
1321 const struct cred *subj_cred;
1322 struct aa_task_ctx *ctx = task_ctx(current);
1323 struct aa_label *label, *previous, *new = NULL, *target = NULL;
1324 struct aa_profile *profile;
1325 struct aa_perms perms = {};
1326 const char *info = NULL;
1327 int error = 0;
1328
1329 /* released below */
1330 subj_cred = get_current_cred();
1331 label = aa_get_newest_cred_label(subj_cred);
1332 previous = aa_get_newest_label(ctx->previous);
1333
1334 /*
1335 * Detect no new privs being set, and store the label it
1336 * occurred under. Ideally this would happen when nnp
1337 * is set but there isn't a good way to do that yet.
1338 *
1339 * Testing for unconfined must be done before the subset test
1340 */
1341 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1342 ctx->nnp = aa_get_label(label);
1343
1344 /* return -EPERM when unconfined doesn't have children to avoid
1345 * changing the traditional error code for unconfined.
1346 */
1347 if (unconfined(label)) {
1348 struct label_it i;
1349 bool empty = true;
1350
1351 rcu_read_lock();
1352 label_for_each_in_scope(i, labels_ns(label), label, profile) {
1353 empty &= list_empty(&profile->base.profiles);
1354 }
1355 rcu_read_unlock();
1356
1357 if (empty) {
1358 info = "unconfined can not change_hat";
1359 error = -EPERM;
1360 goto fail;
1361 }
1362 }
1363
1364 if (count) {
1365 new = change_hat(subj_cred, label, hats, count, flags);
1366 AA_BUG(!new);
1367 if (IS_ERR(new)) {
1368 error = PTR_ERR(new);
1369 new = NULL;
1370 /* already audited */
1371 goto out;
1372 }
1373
1374 /* target cred is the same as current except new label */
1375 error = may_change_ptraced_domain(subj_cred, new, &info);
1376 if (error)
1377 goto fail;
1378
1379 /*
1380 * no new privs prevents domain transitions that would
1381 * reduce restrictions.
1382 */
1383 if (task_no_new_privs(current) && !unconfined(label) &&
1384 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1385 /* not an apparmor denial per se, so don't log it */
1386 AA_DEBUG(DEBUG_DOMAIN,
1387 "no_new_privs - change_hat denied");
1388 error = -EPERM;
1389 goto out;
1390 }
1391
1392 if (flags & AA_CHANGE_TEST)
1393 goto out;
1394
1395 target = new;
1396 error = aa_set_current_hat(new, token);
1397 if (error == -EACCES)
1398 /* kill task in case of brute force attacks */
1399 goto kill;
1400 } else if (previous && !(flags & AA_CHANGE_TEST)) {
1401 /*
1402 * no new privs prevents domain transitions that would
1403 * reduce restrictions.
1404 */
1405 if (task_no_new_privs(current) && !unconfined(label) &&
1406 !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
1407 /* not an apparmor denial per se, so don't log it */
1408 AA_DEBUG(DEBUG_DOMAIN,
1409 "no_new_privs - change_hat denied");
1410 error = -EPERM;
1411 goto out;
1412 }
1413
1414 /* Return to saved label. Kill task if restore fails
1415 * to avoid brute force attacks
1416 */
1417 target = previous;
1418 error = aa_restore_previous_label(token);
1419 if (error) {
1420 if (error == -EACCES)
1421 goto kill;
1422 goto fail;
1423 }
1424 } /* else ignore @flags && restores when there is no saved profile */
1425
1426out:
1427 aa_put_label(new);
1428 aa_put_label(previous);
1429 aa_put_label(label);
1430 put_cred(subj_cred);
1431
1432 return error;
1433
1434kill:
1435 info = "failed token match";
1436 perms.kill = AA_MAY_CHANGEHAT;
1437
1438fail:
1439 fn_for_each_in_scope(label, profile,
1440 aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT,
1441 AA_MAY_CHANGEHAT, NULL, NULL, target,
1442 GLOBAL_ROOT_UID, info, error));
1443
1444 goto out;
1445}
1446
1447
1448static int change_profile_perms_wrapper(const char *op, const char *name,
1449 const struct cred *subj_cred,
1450 struct aa_profile *profile,
1451 struct aa_label *target, bool stack,
1452 u32 request, struct aa_perms *perms)
1453{
1454 struct aa_ruleset *rules = profile->label.rules[0];
1455 const char *info = NULL;
1456 int error = 0;
1457
1458 if (!error)
1459 error = change_profile_perms(profile, target, stack, request,
1460 rules->file->start[AA_CLASS_FILE],
1461 perms);
1462 if (error)
1463 error = aa_audit_file(subj_cred, profile, perms, op, request,
1464 name,
1465 NULL, target, GLOBAL_ROOT_UID, info,
1466 error);
1467
1468 return error;
1469}
1470
1471/**
1472 * aa_change_profile - perform a one-way profile transition
1473 * @fqname: name of profile may include namespace (NOT NULL)
1474 * @flags: flags affecting change behavior
1475 *
1476 * Change to new profile @name. Unlike with hats, there is no way
1477 * to change back. If @name isn't specified the current profile name is
1478 * used.
1479 * If @onexec then the transition is delayed until
1480 * the next exec.
1481 *
1482 * Returns %0 on success, error otherwise.
1483 */
1484int aa_change_profile(const char *fqname, int flags)
1485{
1486 struct aa_label *label, *new = NULL, *target = NULL;
1487 struct aa_profile *profile;
1488 struct aa_perms perms = {};
1489 const char *info = NULL;
1490 const char *auditname = fqname; /* retain leading & if stack */
1491 bool stack = flags & AA_CHANGE_STACK;
1492 struct aa_task_ctx *ctx = task_ctx(current);
1493 const struct cred *subj_cred = get_current_cred();
1494 int error = 0;
1495 char *op;
1496 u32 request;
1497
1498 label = aa_get_current_label();
1499
1500 /*
1501 * Detect no new privs being set, and store the label it
1502 * occurred under. Ideally this would happen when nnp
1503 * is set but there isn't a good way to do that yet.
1504 *
1505 * Testing for unconfined must be done before the subset test
1506 */
1507 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1508 ctx->nnp = aa_get_label(label);
1509
1510 if (!fqname || !*fqname) {
1511 aa_put_label(label);
1512 AA_DEBUG(DEBUG_DOMAIN, "no profile name");
1513 return -EINVAL;
1514 }
1515
1516 if (flags & AA_CHANGE_ONEXEC) {
1517 request = AA_MAY_ONEXEC;
1518 if (stack)
1519 op = OP_STACK_ONEXEC;
1520 else
1521 op = OP_CHANGE_ONEXEC;
1522 } else {
1523 request = AA_MAY_CHANGE_PROFILE;
1524 if (stack)
1525 op = OP_STACK;
1526 else
1527 op = OP_CHANGE_PROFILE;
1528 }
1529
1530 if (*fqname == '&') {
1531 stack = true;
1532 /* don't have label_parse() do stacking */
1533 fqname++;
1534 }
1535 target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1536 if (IS_ERR(target)) {
1537 struct aa_profile *tprofile;
1538
1539 info = "label not found";
1540 error = PTR_ERR(target);
1541 target = NULL;
1542 /*
1543 * TODO: fixme using labels_profile is not right - do profile
1544 * per complain profile
1545 */
1546 if ((flags & AA_CHANGE_TEST) ||
1547 !COMPLAIN_MODE(labels_profile(label)))
1548 goto audit;
1549 /* released below */
1550 tprofile = aa_new_learning_profile(labels_profile(label), false,
1551 fqname, GFP_KERNEL);
1552 if (!tprofile) {
1553 info = "failed null profile create";
1554 error = -ENOMEM;
1555 goto audit;
1556 }
1557 target = &tprofile->label;
1558 goto check;
1559 }
1560
1561 /*
1562 * self directed transitions only apply to current policy ns
1563 * TODO: currently requiring perms for stacking and straight change
1564 * stacking doesn't strictly need this. Determine how much
1565 * we want to loosen this restriction for stacking
1566 *
1567 * if (!stack) {
1568 */
1569 error = fn_for_each_in_scope(label, profile,
1570 change_profile_perms_wrapper(op, auditname,
1571 subj_cred,
1572 profile, target, stack,
1573 request, &perms));
1574 if (error)
1575 /* auditing done in change_profile_perms_wrapper */
1576 goto out;
1577
1578 /* } */
1579
1580check:
1581 /* check if tracing task is allowed to trace target domain */
1582 error = may_change_ptraced_domain(subj_cred, target, &info);
1583 if (error && !fn_for_each_in_scope(label, profile,
1584 COMPLAIN_MODE(profile)))
1585 goto audit;
1586
1587 /* TODO: add permission check to allow this
1588 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1589 * info = "not a single threaded task";
1590 * error = -EACCES;
1591 * goto audit;
1592 * }
1593 */
1594 if (flags & AA_CHANGE_TEST)
1595 goto out;
1596
1597 /* stacking is always a subset, so only check the nonstack case */
1598 if (!stack) {
1599 new = fn_label_build_in_scope(label, profile, GFP_KERNEL,
1600 priv_restricted_transition(subj_cred, profile,
1601 op, request,
1602 auditname, target,
1603 GFP_KERNEL),
1604 aa_get_label(&profile->label));
1605 AA_BUG(!new);
1606 if (IS_ERR(new))
1607 goto build_fail;
1608 /*
1609 * no new privs prevents domain transitions that would
1610 * reduce restrictions.
1611 */
1612 if (task_no_new_privs(current) && !unconfined(label) &&
1613 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1614 /* not an apparmor denial per se, so don't log it */
1615 AA_DEBUG(DEBUG_DOMAIN,
1616 "no_new_privs - change_hat denied");
1617 error = -EPERM;
1618 goto out;
1619 }
1620 }
1621
1622 if (!(flags & AA_CHANGE_ONEXEC)) {
1623 /* only transition profiles in the current ns */
1624 if (stack)
1625 new = aa_label_merge(label, target, GFP_KERNEL);
1626 if (IS_ERR_OR_NULL(new))
1627 goto build_fail;
1628 error = aa_replace_current_label(new);
1629 } else {
1630 /* new will be recomputed so at exec time. So discard */
1631 aa_put_label(new);
1632 new = NULL;
1633
1634 /* full transition will be built in exec path */
1635 aa_set_current_onexec(target, stack);
1636 }
1637
1638 goto audit;
1639
1640build_fail:
1641 info = "failed to build target label";
1642 if (!new)
1643 error = -ENOMEM;
1644 else
1645 error = PTR_ERR(new);
1646 new = NULL;
1647 perms.allow = 0;
1648
1649audit:
1650 error = fn_for_each_in_scope(label, profile,
1651 aa_audit_file(subj_cred,
1652 profile, &perms, op, request, auditname,
1653 NULL, new ? new : target,
1654 GLOBAL_ROOT_UID, info, error));
1655
1656out:
1657 aa_put_label(new);
1658 aa_put_label(target);
1659 aa_put_label(label);
1660 put_cred(subj_cred);
1661
1662 return error;
1663}