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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// 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/fs.h>
14#include <linux/file.h>
15#include <linux/mount.h>
16#include <linux/syscalls.h>
17#include <linux/tracehook.h>
18#include <linux/personality.h>
19#include <linux/xattr.h>
20#include <linux/user_namespace.h>
21
22#include "include/audit.h"
23#include "include/apparmorfs.h"
24#include "include/cred.h"
25#include "include/domain.h"
26#include "include/file.h"
27#include "include/ipc.h"
28#include "include/match.h"
29#include "include/path.h"
30#include "include/policy.h"
31#include "include/policy_ns.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 kfree_sensitive(domain->table[i]);
46 kfree_sensitive(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_label: profile to change to (NOT NULL)
54 * @info: message if there is an error
55 *
56 * Check if current is ptraced and if so if the tracing task is allowed
57 * to trace the new domain
58 *
59 * Returns: %0 or error if change not allowed
60 */
61static int may_change_ptraced_domain(struct aa_label *to_label,
62 const char **info)
63{
64 struct task_struct *tracer;
65 struct aa_label *tracerl = NULL;
66 int error = 0;
67
68 rcu_read_lock();
69 tracer = ptrace_parent(current);
70 if (tracer)
71 /* released below */
72 tracerl = aa_get_task_label(tracer);
73
74 /* not ptraced */
75 if (!tracer || unconfined(tracerl))
76 goto out;
77
78 error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH);
79
80out:
81 rcu_read_unlock();
82 aa_put_label(tracerl);
83
84 if (error)
85 *info = "ptrace prevents transition";
86 return error;
87}
88
89/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
90 * specifically this is an exact copy of aa_label_match except
91 * aa_compute_perms is replaced with aa_compute_fperms
92 * and policy.dfa with file.dfa
93 ****/
94/* match a profile and its associated ns component if needed
95 * Assumes visibility test has already been done.
96 * If a subns profile is not to be matched should be prescreened with
97 * visibility test.
98 */
99static inline unsigned int match_component(struct aa_profile *profile,
100 struct aa_profile *tp,
101 bool stack, unsigned int state)
102{
103 const char *ns_name;
104
105 if (stack)
106 state = aa_dfa_match(profile->file.dfa, state, "&");
107 if (profile->ns == tp->ns)
108 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
109
110 /* try matching with namespace name and then profile */
111 ns_name = aa_ns_name(profile->ns, tp->ns, true);
112 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
113 state = aa_dfa_match(profile->file.dfa, state, ns_name);
114 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
115 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
116}
117
118/**
119 * label_compound_match - find perms for full compound label
120 * @profile: profile to find perms for
121 * @label: label to check access permissions for
122 * @stack: whether this is a stacking request
123 * @start: state to start match in
124 * @subns: whether to do permission checks on components in a subns
125 * @request: permissions to request
126 * @perms: perms struct to set
127 *
128 * Returns: 0 on success else ERROR
129 *
130 * For the label A//&B//&C this does the perm match for A//&B//&C
131 * @perms should be preinitialized with allperms OR a previous permission
132 * check to be stacked.
133 */
134static int label_compound_match(struct aa_profile *profile,
135 struct aa_label *label, bool stack,
136 unsigned int state, bool subns, u32 request,
137 struct aa_perms *perms)
138{
139 struct aa_profile *tp;
140 struct label_it i;
141 struct path_cond cond = { };
142
143 /* find first subcomponent that is visible */
144 label_for_each(i, label, tp) {
145 if (!aa_ns_visible(profile->ns, tp->ns, subns))
146 continue;
147 state = match_component(profile, tp, stack, state);
148 if (!state)
149 goto fail;
150 goto next;
151 }
152
153 /* no component visible */
154 *perms = allperms;
155 return 0;
156
157next:
158 label_for_each_cont(i, label, tp) {
159 if (!aa_ns_visible(profile->ns, tp->ns, subns))
160 continue;
161 state = aa_dfa_match(profile->file.dfa, state, "//&");
162 state = match_component(profile, tp, false, state);
163 if (!state)
164 goto fail;
165 }
166 *perms = aa_compute_fperms(profile->file.dfa, state, &cond);
167 aa_apply_modes_to_perms(profile, perms);
168 if ((perms->allow & request) != request)
169 return -EACCES;
170
171 return 0;
172
173fail:
174 *perms = nullperms;
175 return -EACCES;
176}
177
178/**
179 * label_components_match - find perms for all subcomponents of a label
180 * @profile: profile to find perms for
181 * @label: label to check access permissions for
182 * @stack: whether this is a stacking request
183 * @start: state to start match in
184 * @subns: whether to do permission checks on components in a subns
185 * @request: permissions to request
186 * @perms: an initialized perms struct to add accumulation to
187 *
188 * Returns: 0 on success else ERROR
189 *
190 * For the label A//&B//&C this does the perm match for each of A and B and C
191 * @perms should be preinitialized with allperms OR a previous permission
192 * check to be stacked.
193 */
194static int label_components_match(struct aa_profile *profile,
195 struct aa_label *label, bool stack,
196 unsigned int start, bool subns, u32 request,
197 struct aa_perms *perms)
198{
199 struct aa_profile *tp;
200 struct label_it i;
201 struct aa_perms tmp;
202 struct path_cond cond = { };
203 unsigned int state = 0;
204
205 /* find first subcomponent to test */
206 label_for_each(i, label, tp) {
207 if (!aa_ns_visible(profile->ns, tp->ns, subns))
208 continue;
209 state = match_component(profile, tp, stack, start);
210 if (!state)
211 goto fail;
212 goto next;
213 }
214
215 /* no subcomponents visible - no change in perms */
216 return 0;
217
218next:
219 tmp = aa_compute_fperms(profile->file.dfa, state, &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, subns))
224 continue;
225 state = match_component(profile, tp, stack, start);
226 if (!state)
227 goto fail;
228 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
229 aa_apply_modes_to_perms(profile, &tmp);
230 aa_perms_accum(perms, &tmp);
231 }
232
233 if ((perms->allow & request) != request)
234 return -EACCES;
235
236 return 0;
237
238fail:
239 *perms = nullperms;
240 return -EACCES;
241}
242
243/**
244 * label_match - do a multi-component label match
245 * @profile: profile to match against (NOT NULL)
246 * @label: label to match (NOT NULL)
247 * @stack: whether this is a stacking request
248 * @state: state to start in
249 * @subns: whether to match subns components
250 * @request: permission request
251 * @perms: Returns computed perms (NOT NULL)
252 *
253 * Returns: the state the match finished in, may be the none matching state
254 */
255static int label_match(struct aa_profile *profile, struct aa_label *label,
256 bool stack, unsigned int state, bool subns, u32 request,
257 struct aa_perms *perms)
258{
259 int error;
260
261 *perms = nullperms;
262 error = label_compound_match(profile, label, stack, state, subns,
263 request, perms);
264 if (!error)
265 return error;
266
267 *perms = allperms;
268 return label_components_match(profile, label, stack, state, subns,
269 request, perms);
270}
271
272/******* end TODO: dedup *****/
273
274/**
275 * change_profile_perms - find permissions for change_profile
276 * @profile: the current profile (NOT NULL)
277 * @target: label to transition to (NOT NULL)
278 * @stack: whether this is a stacking request
279 * @request: requested perms
280 * @start: state to start matching in
281 *
282 *
283 * Returns: permission set
284 *
285 * currently only matches full label A//&B//&C or individual components A, B, C
286 * not arbitrary combinations. Eg. A//&B, C
287 */
288static int change_profile_perms(struct aa_profile *profile,
289 struct aa_label *target, bool stack,
290 u32 request, unsigned int start,
291 struct aa_perms *perms)
292{
293 if (profile_unconfined(profile)) {
294 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
295 perms->audit = perms->quiet = perms->kill = 0;
296 return 0;
297 }
298
299 /* TODO: add profile in ns screening */
300 return label_match(profile, target, stack, start, true, request, perms);
301}
302
303/**
304 * aa_xattrs_match - check whether a file matches the xattrs defined in profile
305 * @bprm: binprm struct for the process to validate
306 * @profile: profile to match against (NOT NULL)
307 * @state: state to start match in
308 *
309 * Returns: number of extended attributes that matched, or < 0 on error
310 */
311static int aa_xattrs_match(const struct linux_binprm *bprm,
312 struct aa_profile *profile, unsigned int state)
313{
314 int i;
315 ssize_t size;
316 struct dentry *d;
317 char *value = NULL;
318 int value_size = 0, ret = profile->xattr_count;
319
320 if (!bprm || !profile->xattr_count)
321 return 0;
322 might_sleep();
323
324 /* transition from exec match to xattr set */
325 state = aa_dfa_outofband_transition(profile->xmatch, state);
326 d = bprm->file->f_path.dentry;
327
328 for (i = 0; i < profile->xattr_count; i++) {
329 size = vfs_getxattr_alloc(&init_user_ns, d, profile->xattrs[i],
330 &value, value_size, GFP_KERNEL);
331 if (size >= 0) {
332 u32 perm;
333
334 /*
335 * Check the xattr presence before value. This ensure
336 * that not present xattr can be distinguished from a 0
337 * length value or rule that matches any value
338 */
339 state = aa_dfa_null_transition(profile->xmatch, state);
340 /* Check xattr value */
341 state = aa_dfa_match_len(profile->xmatch, state, value,
342 size);
343 perm = dfa_user_allow(profile->xmatch, state);
344 if (!(perm & MAY_EXEC)) {
345 ret = -EINVAL;
346 goto out;
347 }
348 }
349 /* transition to next element */
350 state = aa_dfa_outofband_transition(profile->xmatch, state);
351 if (size < 0) {
352 /*
353 * No xattr match, so verify if transition to
354 * next element was valid. IFF so the xattr
355 * was optional.
356 */
357 if (!state) {
358 ret = -EINVAL;
359 goto out;
360 }
361 /* don't count missing optional xattr as matched */
362 ret--;
363 }
364 }
365
366out:
367 kfree(value);
368 return ret;
369}
370
371/**
372 * find_attach - do attachment search for unconfined processes
373 * @bprm - binprm structure of transitioning task
374 * @ns: the current namespace (NOT NULL)
375 * @head - profile list to walk (NOT NULL)
376 * @name - to match against (NOT NULL)
377 * @info - info message if there was an error (NOT NULL)
378 *
379 * Do a linear search on the profiles in the list. There is a matching
380 * preference where an exact match is preferred over a name which uses
381 * expressions to match, and matching expressions with the greatest
382 * xmatch_len are preferred.
383 *
384 * Requires: @head not be shared or have appropriate locks held
385 *
386 * Returns: label or NULL if no match found
387 */
388static struct aa_label *find_attach(const struct linux_binprm *bprm,
389 struct aa_ns *ns, struct list_head *head,
390 const char *name, const char **info)
391{
392 int candidate_len = 0, candidate_xattrs = 0;
393 bool conflict = false;
394 struct aa_profile *profile, *candidate = NULL;
395
396 AA_BUG(!name);
397 AA_BUG(!head);
398
399 rcu_read_lock();
400restart:
401 list_for_each_entry_rcu(profile, head, base.list) {
402 if (profile->label.flags & FLAG_NULL &&
403 &profile->label == ns_unconfined(profile->ns))
404 continue;
405
406 /* Find the "best" matching profile. Profiles must
407 * match the path and extended attributes (if any)
408 * associated with the file. A more specific path
409 * match will be preferred over a less specific one,
410 * and a match with more matching extended attributes
411 * will be preferred over one with fewer. If the best
412 * match has both the same level of path specificity
413 * and the same number of matching extended attributes
414 * as another profile, signal a conflict and refuse to
415 * match.
416 */
417 if (profile->xmatch) {
418 unsigned int state, count;
419 u32 perm;
420
421 state = aa_dfa_leftmatch(profile->xmatch, DFA_START,
422 name, &count);
423 perm = dfa_user_allow(profile->xmatch, state);
424 /* any accepting state means a valid match. */
425 if (perm & MAY_EXEC) {
426 int ret = 0;
427
428 if (count < candidate_len)
429 continue;
430
431 if (bprm && profile->xattr_count) {
432 long rev = READ_ONCE(ns->revision);
433
434 if (!aa_get_profile_not0(profile))
435 goto restart;
436 rcu_read_unlock();
437 ret = aa_xattrs_match(bprm, profile,
438 state);
439 rcu_read_lock();
440 aa_put_profile(profile);
441 if (rev !=
442 READ_ONCE(ns->revision))
443 /* policy changed */
444 goto restart;
445 /*
446 * Fail matching if the xattrs don't
447 * match
448 */
449 if (ret < 0)
450 continue;
451 }
452 /*
453 * TODO: allow for more flexible best match
454 *
455 * The new match isn't more specific
456 * than the current best match
457 */
458 if (count == candidate_len &&
459 ret <= candidate_xattrs) {
460 /* Match is equivalent, so conflict */
461 if (ret == candidate_xattrs)
462 conflict = true;
463 continue;
464 }
465
466 /* Either the same length with more matching
467 * xattrs, or a longer match
468 */
469 candidate = profile;
470 candidate_len = profile->xmatch_len;
471 candidate_xattrs = ret;
472 conflict = false;
473 }
474 } else if (!strcmp(profile->base.name, name)) {
475 /*
476 * old exact non-re match, without conditionals such
477 * as xattrs. no more searching required
478 */
479 candidate = profile;
480 goto out;
481 }
482 }
483
484 if (!candidate || conflict) {
485 if (conflict)
486 *info = "conflicting profile attachments";
487 rcu_read_unlock();
488 return NULL;
489 }
490
491out:
492 candidate = aa_get_newest_profile(candidate);
493 rcu_read_unlock();
494
495 return &candidate->label;
496}
497
498static const char *next_name(int xtype, const char *name)
499{
500 return NULL;
501}
502
503/**
504 * x_table_lookup - lookup an x transition name via transition table
505 * @profile: current profile (NOT NULL)
506 * @xindex: index into x transition table
507 * @name: returns: name tested to find label (NOT NULL)
508 *
509 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
510 */
511struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
512 const char **name)
513{
514 struct aa_label *label = NULL;
515 u32 xtype = xindex & AA_X_TYPE_MASK;
516 int index = xindex & AA_X_INDEX_MASK;
517
518 AA_BUG(!name);
519
520 /* index is guaranteed to be in range, validated at load time */
521 /* TODO: move lookup parsing to unpack time so this is a straight
522 * index into the resultant label
523 */
524 for (*name = profile->file.trans.table[index]; !label && *name;
525 *name = next_name(xtype, *name)) {
526 if (xindex & AA_X_CHILD) {
527 struct aa_profile *new_profile;
528 /* release by caller */
529 new_profile = aa_find_child(profile, *name);
530 if (new_profile)
531 label = &new_profile->label;
532 continue;
533 }
534 label = aa_label_parse(&profile->label, *name, GFP_KERNEL,
535 true, false);
536 if (IS_ERR(label))
537 label = NULL;
538 }
539
540 /* released by caller */
541
542 return label;
543}
544
545/**
546 * x_to_label - get target label for a given xindex
547 * @profile: current profile (NOT NULL)
548 * @bprm: binprm structure of transitioning task
549 * @name: name to lookup (NOT NULL)
550 * @xindex: index into x transition table
551 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
552 *
553 * find label for a transition index
554 *
555 * Returns: refcounted label or NULL if not found available
556 */
557static struct aa_label *x_to_label(struct aa_profile *profile,
558 const struct linux_binprm *bprm,
559 const char *name, u32 xindex,
560 const char **lookupname,
561 const char **info)
562{
563 struct aa_label *new = NULL;
564 struct aa_ns *ns = profile->ns;
565 u32 xtype = xindex & AA_X_TYPE_MASK;
566 const char *stack = NULL;
567
568 switch (xtype) {
569 case AA_X_NONE:
570 /* fail exec unless ix || ux fallback - handled by caller */
571 *lookupname = NULL;
572 break;
573 case AA_X_TABLE:
574 /* TODO: fix when perm mapping done at unload */
575 stack = profile->file.trans.table[xindex & AA_X_INDEX_MASK];
576 if (*stack != '&') {
577 /* released by caller */
578 new = x_table_lookup(profile, xindex, lookupname);
579 stack = NULL;
580 break;
581 }
582 fallthrough; /* to X_NAME */
583 case AA_X_NAME:
584 if (xindex & AA_X_CHILD)
585 /* released by caller */
586 new = find_attach(bprm, ns, &profile->base.profiles,
587 name, info);
588 else
589 /* released by caller */
590 new = find_attach(bprm, ns, &ns->base.profiles,
591 name, info);
592 *lookupname = name;
593 break;
594 }
595
596 if (!new) {
597 if (xindex & AA_X_INHERIT) {
598 /* (p|c|n)ix - don't change profile but do
599 * use the newest version
600 */
601 *info = "ix fallback";
602 /* no profile && no error */
603 new = aa_get_newest_label(&profile->label);
604 } else if (xindex & AA_X_UNCONFINED) {
605 new = aa_get_newest_label(ns_unconfined(profile->ns));
606 *info = "ux fallback";
607 }
608 }
609
610 if (new && stack) {
611 /* base the stack on post domain transition */
612 struct aa_label *base = new;
613
614 new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
615 if (IS_ERR(new))
616 new = NULL;
617 aa_put_label(base);
618 }
619
620 /* released by caller */
621 return new;
622}
623
624static struct aa_label *profile_transition(struct aa_profile *profile,
625 const struct linux_binprm *bprm,
626 char *buffer, struct path_cond *cond,
627 bool *secure_exec)
628{
629 struct aa_label *new = NULL;
630 const char *info = NULL, *name = NULL, *target = NULL;
631 unsigned int state = profile->file.start;
632 struct aa_perms perms = {};
633 bool nonewprivs = false;
634 int error = 0;
635
636 AA_BUG(!profile);
637 AA_BUG(!bprm);
638 AA_BUG(!buffer);
639
640 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
641 &name, &info, profile->disconnected);
642 if (error) {
643 if (profile_unconfined(profile) ||
644 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
645 AA_DEBUG("name lookup ix on error");
646 error = 0;
647 new = aa_get_newest_label(&profile->label);
648 }
649 name = bprm->filename;
650 goto audit;
651 }
652
653 if (profile_unconfined(profile)) {
654 new = find_attach(bprm, profile->ns,
655 &profile->ns->base.profiles, name, &info);
656 if (new) {
657 AA_DEBUG("unconfined attached to new label");
658 return new;
659 }
660 AA_DEBUG("unconfined exec no attachment");
661 return aa_get_newest_label(&profile->label);
662 }
663
664 /* find exec permissions for name */
665 state = aa_str_perms(profile->file.dfa, state, name, cond, &perms);
666 if (perms.allow & MAY_EXEC) {
667 /* exec permission determine how to transition */
668 new = x_to_label(profile, bprm, name, perms.xindex, &target,
669 &info);
670 if (new && new->proxy == profile->label.proxy && info) {
671 /* hack ix fallback - improve how this is detected */
672 goto audit;
673 } else if (!new) {
674 error = -EACCES;
675 info = "profile transition not found";
676 /* remove MAY_EXEC to audit as failure */
677 perms.allow &= ~MAY_EXEC;
678 }
679 } else if (COMPLAIN_MODE(profile)) {
680 /* no exec permission - learning mode */
681 struct aa_profile *new_profile = NULL;
682
683 new_profile = aa_new_null_profile(profile, false, name,
684 GFP_KERNEL);
685 if (!new_profile) {
686 error = -ENOMEM;
687 info = "could not create null profile";
688 } else {
689 error = -EACCES;
690 new = &new_profile->label;
691 }
692 perms.xindex |= AA_X_UNSAFE;
693 } else
694 /* fail exec */
695 error = -EACCES;
696
697 if (!new)
698 goto audit;
699
700
701 if (!(perms.xindex & AA_X_UNSAFE)) {
702 if (DEBUG_ON) {
703 dbg_printk("apparmor: scrubbing environment variables"
704 " for %s profile=", name);
705 aa_label_printk(new, GFP_KERNEL);
706 dbg_printk("\n");
707 }
708 *secure_exec = true;
709 }
710
711audit:
712 aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
713 cond->uid, info, error);
714 if (!new || nonewprivs) {
715 aa_put_label(new);
716 return ERR_PTR(error);
717 }
718
719 return new;
720}
721
722static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
723 bool stack, const struct linux_binprm *bprm,
724 char *buffer, struct path_cond *cond,
725 bool *secure_exec)
726{
727 unsigned int state = profile->file.start;
728 struct aa_perms perms = {};
729 const char *xname = NULL, *info = "change_profile onexec";
730 int error = -EACCES;
731
732 AA_BUG(!profile);
733 AA_BUG(!onexec);
734 AA_BUG(!bprm);
735 AA_BUG(!buffer);
736
737 if (profile_unconfined(profile)) {
738 /* change_profile on exec already granted */
739 /*
740 * NOTE: Domain transitions from unconfined are allowed
741 * even when no_new_privs is set because this aways results
742 * in a further reduction of permissions.
743 */
744 return 0;
745 }
746
747 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
748 &xname, &info, profile->disconnected);
749 if (error) {
750 if (profile_unconfined(profile) ||
751 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
752 AA_DEBUG("name lookup ix on error");
753 error = 0;
754 }
755 xname = bprm->filename;
756 goto audit;
757 }
758
759 /* find exec permissions for name */
760 state = aa_str_perms(profile->file.dfa, state, xname, cond, &perms);
761 if (!(perms.allow & AA_MAY_ONEXEC)) {
762 info = "no change_onexec valid for executable";
763 goto audit;
764 }
765 /* test if this exec can be paired with change_profile onexec.
766 * onexec permission is linked to exec with a standard pairing
767 * exec\0change_profile
768 */
769 state = aa_dfa_null_transition(profile->file.dfa, state);
770 error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
771 state, &perms);
772 if (error) {
773 perms.allow &= ~AA_MAY_ONEXEC;
774 goto audit;
775 }
776
777 if (!(perms.xindex & AA_X_UNSAFE)) {
778 if (DEBUG_ON) {
779 dbg_printk("apparmor: scrubbing environment "
780 "variables for %s label=", xname);
781 aa_label_printk(onexec, GFP_KERNEL);
782 dbg_printk("\n");
783 }
784 *secure_exec = true;
785 }
786
787audit:
788 return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
789 NULL, onexec, cond->uid, info, error);
790}
791
792/* ensure none ns domain transitions are correctly applied with onexec */
793
794static struct aa_label *handle_onexec(struct aa_label *label,
795 struct aa_label *onexec, bool stack,
796 const struct linux_binprm *bprm,
797 char *buffer, struct path_cond *cond,
798 bool *unsafe)
799{
800 struct aa_profile *profile;
801 struct aa_label *new;
802 int error;
803
804 AA_BUG(!label);
805 AA_BUG(!onexec);
806 AA_BUG(!bprm);
807 AA_BUG(!buffer);
808
809 if (!stack) {
810 error = fn_for_each_in_ns(label, profile,
811 profile_onexec(profile, onexec, stack,
812 bprm, buffer, cond, unsafe));
813 if (error)
814 return ERR_PTR(error);
815 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
816 aa_get_newest_label(onexec),
817 profile_transition(profile, bprm, buffer,
818 cond, unsafe));
819
820 } else {
821 /* TODO: determine how much we want to loosen this */
822 error = fn_for_each_in_ns(label, profile,
823 profile_onexec(profile, onexec, stack, bprm,
824 buffer, cond, unsafe));
825 if (error)
826 return ERR_PTR(error);
827 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
828 aa_label_merge(&profile->label, onexec,
829 GFP_KERNEL),
830 profile_transition(profile, bprm, buffer,
831 cond, unsafe));
832 }
833
834 if (new)
835 return new;
836
837 /* TODO: get rid of GLOBAL_ROOT_UID */
838 error = fn_for_each_in_ns(label, profile,
839 aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
840 AA_MAY_ONEXEC, bprm->filename, NULL,
841 onexec, GLOBAL_ROOT_UID,
842 "failed to build target label", -ENOMEM));
843 return ERR_PTR(error);
844}
845
846/**
847 * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
848 * @bprm: binprm for the exec (NOT NULL)
849 *
850 * Returns: %0 or error on failure
851 *
852 * TODO: once the other paths are done see if we can't refactor into a fn
853 */
854int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
855{
856 struct aa_task_ctx *ctx;
857 struct aa_label *label, *new = NULL;
858 struct aa_profile *profile;
859 char *buffer = NULL;
860 const char *info = NULL;
861 int error = 0;
862 bool unsafe = false;
863 kuid_t i_uid = i_uid_into_mnt(file_mnt_user_ns(bprm->file),
864 file_inode(bprm->file));
865 struct path_cond cond = {
866 i_uid,
867 file_inode(bprm->file)->i_mode
868 };
869
870 ctx = task_ctx(current);
871 AA_BUG(!cred_label(bprm->cred));
872 AA_BUG(!ctx);
873
874 label = aa_get_newest_label(cred_label(bprm->cred));
875
876 /*
877 * Detect no new privs being set, and store the label it
878 * occurred under. Ideally this would happen when nnp
879 * is set but there isn't a good way to do that yet.
880 *
881 * Testing for unconfined must be done before the subset test
882 */
883 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
884 !ctx->nnp)
885 ctx->nnp = aa_get_label(label);
886
887 /* buffer freed below, name is pointer into buffer */
888 buffer = aa_get_buffer(false);
889 if (!buffer) {
890 error = -ENOMEM;
891 goto done;
892 }
893
894 /* Test for onexec first as onexec override other x transitions. */
895 if (ctx->onexec)
896 new = handle_onexec(label, ctx->onexec, ctx->token,
897 bprm, buffer, &cond, &unsafe);
898 else
899 new = fn_label_build(label, profile, GFP_KERNEL,
900 profile_transition(profile, bprm, buffer,
901 &cond, &unsafe));
902
903 AA_BUG(!new);
904 if (IS_ERR(new)) {
905 error = PTR_ERR(new);
906 goto done;
907 } else if (!new) {
908 error = -ENOMEM;
909 goto done;
910 }
911
912 /* Policy has specified a domain transitions. If no_new_privs and
913 * confined ensure the transition is to confinement that is subset
914 * of the confinement when the task entered no new privs.
915 *
916 * NOTE: Domain transitions from unconfined and to stacked
917 * subsets are allowed even when no_new_privs is set because this
918 * aways results in a further reduction of permissions.
919 */
920 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
921 !unconfined(label) &&
922 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
923 error = -EPERM;
924 info = "no new privs";
925 goto audit;
926 }
927
928 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
929 /* FIXME: currently don't mediate shared state */
930 ;
931 }
932
933 if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
934 /* TODO: test needs to be profile of label to new */
935 error = may_change_ptraced_domain(new, &info);
936 if (error)
937 goto audit;
938 }
939
940 if (unsafe) {
941 if (DEBUG_ON) {
942 dbg_printk("scrubbing environment variables for %s "
943 "label=", bprm->filename);
944 aa_label_printk(new, GFP_KERNEL);
945 dbg_printk("\n");
946 }
947 bprm->secureexec = 1;
948 }
949
950 if (label->proxy != new->proxy) {
951 /* when transitioning clear unsafe personality bits */
952 if (DEBUG_ON) {
953 dbg_printk("apparmor: clearing unsafe personality "
954 "bits. %s label=", bprm->filename);
955 aa_label_printk(new, GFP_KERNEL);
956 dbg_printk("\n");
957 }
958 bprm->per_clear |= PER_CLEAR_ON_SETID;
959 }
960 aa_put_label(cred_label(bprm->cred));
961 /* transfer reference, released when cred is freed */
962 set_cred_label(bprm->cred, new);
963
964done:
965 aa_put_label(label);
966 aa_put_buffer(buffer);
967
968 return error;
969
970audit:
971 error = fn_for_each(label, profile,
972 aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
973 bprm->filename, NULL, new,
974 i_uid, info, error));
975 aa_put_label(new);
976 goto done;
977}
978
979/*
980 * Functions for self directed profile change
981 */
982
983
984/* helper fn for change_hat
985 *
986 * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL
987 */
988static struct aa_label *build_change_hat(struct aa_profile *profile,
989 const char *name, bool sibling)
990{
991 struct aa_profile *root, *hat = NULL;
992 const char *info = NULL;
993 int error = 0;
994
995 if (sibling && PROFILE_IS_HAT(profile)) {
996 root = aa_get_profile_rcu(&profile->parent);
997 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
998 root = aa_get_profile(profile);
999 } else {
1000 info = "conflicting target types";
1001 error = -EPERM;
1002 goto audit;
1003 }
1004
1005 hat = aa_find_child(root, name);
1006 if (!hat) {
1007 error = -ENOENT;
1008 if (COMPLAIN_MODE(profile)) {
1009 hat = aa_new_null_profile(profile, true, name,
1010 GFP_KERNEL);
1011 if (!hat) {
1012 info = "failed null profile create";
1013 error = -ENOMEM;
1014 }
1015 }
1016 }
1017 aa_put_profile(root);
1018
1019audit:
1020 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT, AA_MAY_CHANGEHAT,
1021 name, hat ? hat->base.hname : NULL,
1022 hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1023 error);
1024 if (!hat || (error && error != -ENOENT))
1025 return ERR_PTR(error);
1026 /* if hat && error - complain mode, already audited and we adjust for
1027 * complain mode allow by returning hat->label
1028 */
1029 return &hat->label;
1030}
1031
1032/* helper fn for changing into a hat
1033 *
1034 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1035 */
1036static struct aa_label *change_hat(struct aa_label *label, const char *hats[],
1037 int count, int flags)
1038{
1039 struct aa_profile *profile, *root, *hat = NULL;
1040 struct aa_label *new;
1041 struct label_it it;
1042 bool sibling = false;
1043 const char *name, *info = NULL;
1044 int i, error;
1045
1046 AA_BUG(!label);
1047 AA_BUG(!hats);
1048 AA_BUG(count < 1);
1049
1050 if (PROFILE_IS_HAT(labels_profile(label)))
1051 sibling = true;
1052
1053 /*find first matching hat */
1054 for (i = 0; i < count && !hat; i++) {
1055 name = hats[i];
1056 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1057 if (sibling && PROFILE_IS_HAT(profile)) {
1058 root = aa_get_profile_rcu(&profile->parent);
1059 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1060 root = aa_get_profile(profile);
1061 } else { /* conflicting change type */
1062 info = "conflicting targets types";
1063 error = -EPERM;
1064 goto fail;
1065 }
1066 hat = aa_find_child(root, name);
1067 aa_put_profile(root);
1068 if (!hat) {
1069 if (!COMPLAIN_MODE(profile))
1070 goto outer_continue;
1071 /* complain mode succeed as if hat */
1072 } else if (!PROFILE_IS_HAT(hat)) {
1073 info = "target not hat";
1074 error = -EPERM;
1075 aa_put_profile(hat);
1076 goto fail;
1077 }
1078 aa_put_profile(hat);
1079 }
1080 /* found a hat for all profiles in ns */
1081 goto build;
1082outer_continue:
1083 ;
1084 }
1085 /* no hats that match, find appropriate error
1086 *
1087 * In complain mode audit of the failure is based off of the first
1088 * hat supplied. This is done due how userspace interacts with
1089 * change_hat.
1090 */
1091 name = NULL;
1092 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1093 if (!list_empty(&profile->base.profiles)) {
1094 info = "hat not found";
1095 error = -ENOENT;
1096 goto fail;
1097 }
1098 }
1099 info = "no hats defined";
1100 error = -ECHILD;
1101
1102fail:
1103 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1104 /*
1105 * no target as it has failed to be found or built
1106 *
1107 * change_hat uses probing and should not log failures
1108 * related to missing hats
1109 */
1110 /* TODO: get rid of GLOBAL_ROOT_UID */
1111 if (count > 1 || COMPLAIN_MODE(profile)) {
1112 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT,
1113 AA_MAY_CHANGEHAT, name, NULL, NULL,
1114 GLOBAL_ROOT_UID, info, error);
1115 }
1116 }
1117 return ERR_PTR(error);
1118
1119build:
1120 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1121 build_change_hat(profile, name, sibling),
1122 aa_get_label(&profile->label));
1123 if (!new) {
1124 info = "label build failed";
1125 error = -ENOMEM;
1126 goto fail;
1127 } /* else if (IS_ERR) build_change_hat has logged error so return new */
1128
1129 return new;
1130}
1131
1132/**
1133 * aa_change_hat - change hat to/from subprofile
1134 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1135 * @count: number of hat names in @hats
1136 * @token: magic value to validate the hat change
1137 * @flags: flags affecting behavior of the change
1138 *
1139 * Returns %0 on success, error otherwise.
1140 *
1141 * Change to the first profile specified in @hats that exists, and store
1142 * the @hat_magic in the current task context. If the count == 0 and the
1143 * @token matches that stored in the current task context, return to the
1144 * top level profile.
1145 *
1146 * change_hat only applies to profiles in the current ns, and each profile
1147 * in the ns must make the same transition otherwise change_hat will fail.
1148 */
1149int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1150{
1151 const struct cred *cred;
1152 struct aa_task_ctx *ctx = task_ctx(current);
1153 struct aa_label *label, *previous, *new = NULL, *target = NULL;
1154 struct aa_profile *profile;
1155 struct aa_perms perms = {};
1156 const char *info = NULL;
1157 int error = 0;
1158
1159 /* released below */
1160 cred = get_current_cred();
1161 label = aa_get_newest_cred_label(cred);
1162 previous = aa_get_newest_label(ctx->previous);
1163
1164 /*
1165 * Detect no new privs being set, and store the label it
1166 * occurred under. Ideally this would happen when nnp
1167 * is set but there isn't a good way to do that yet.
1168 *
1169 * Testing for unconfined must be done before the subset test
1170 */
1171 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1172 ctx->nnp = aa_get_label(label);
1173
1174 if (unconfined(label)) {
1175 info = "unconfined can not change_hat";
1176 error = -EPERM;
1177 goto fail;
1178 }
1179
1180 if (count) {
1181 new = change_hat(label, hats, count, flags);
1182 AA_BUG(!new);
1183 if (IS_ERR(new)) {
1184 error = PTR_ERR(new);
1185 new = NULL;
1186 /* already audited */
1187 goto out;
1188 }
1189
1190 error = may_change_ptraced_domain(new, &info);
1191 if (error)
1192 goto fail;
1193
1194 /*
1195 * no new privs prevents domain transitions that would
1196 * reduce restrictions.
1197 */
1198 if (task_no_new_privs(current) && !unconfined(label) &&
1199 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1200 /* not an apparmor denial per se, so don't log it */
1201 AA_DEBUG("no_new_privs - change_hat denied");
1202 error = -EPERM;
1203 goto out;
1204 }
1205
1206 if (flags & AA_CHANGE_TEST)
1207 goto out;
1208
1209 target = new;
1210 error = aa_set_current_hat(new, token);
1211 if (error == -EACCES)
1212 /* kill task in case of brute force attacks */
1213 goto kill;
1214 } else if (previous && !(flags & AA_CHANGE_TEST)) {
1215 /*
1216 * no new privs prevents domain transitions that would
1217 * reduce restrictions.
1218 */
1219 if (task_no_new_privs(current) && !unconfined(label) &&
1220 !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
1221 /* not an apparmor denial per se, so don't log it */
1222 AA_DEBUG("no_new_privs - change_hat denied");
1223 error = -EPERM;
1224 goto out;
1225 }
1226
1227 /* Return to saved label. Kill task if restore fails
1228 * to avoid brute force attacks
1229 */
1230 target = previous;
1231 error = aa_restore_previous_label(token);
1232 if (error) {
1233 if (error == -EACCES)
1234 goto kill;
1235 goto fail;
1236 }
1237 } /* else ignore @flags && restores when there is no saved profile */
1238
1239out:
1240 aa_put_label(new);
1241 aa_put_label(previous);
1242 aa_put_label(label);
1243 put_cred(cred);
1244
1245 return error;
1246
1247kill:
1248 info = "failed token match";
1249 perms.kill = AA_MAY_CHANGEHAT;
1250
1251fail:
1252 fn_for_each_in_ns(label, profile,
1253 aa_audit_file(profile, &perms, OP_CHANGE_HAT,
1254 AA_MAY_CHANGEHAT, NULL, NULL, target,
1255 GLOBAL_ROOT_UID, info, error));
1256
1257 goto out;
1258}
1259
1260
1261static int change_profile_perms_wrapper(const char *op, const char *name,
1262 struct aa_profile *profile,
1263 struct aa_label *target, bool stack,
1264 u32 request, struct aa_perms *perms)
1265{
1266 const char *info = NULL;
1267 int error = 0;
1268
1269 if (!error)
1270 error = change_profile_perms(profile, target, stack, request,
1271 profile->file.start, perms);
1272 if (error)
1273 error = aa_audit_file(profile, perms, op, request, name,
1274 NULL, target, GLOBAL_ROOT_UID, info,
1275 error);
1276
1277 return error;
1278}
1279
1280/**
1281 * aa_change_profile - perform a one-way profile transition
1282 * @fqname: name of profile may include namespace (NOT NULL)
1283 * @onexec: whether this transition is to take place immediately or at exec
1284 * @flags: flags affecting change behavior
1285 *
1286 * Change to new profile @name. Unlike with hats, there is no way
1287 * to change back. If @name isn't specified the current profile name is
1288 * used.
1289 * If @onexec then the transition is delayed until
1290 * the next exec.
1291 *
1292 * Returns %0 on success, error otherwise.
1293 */
1294int aa_change_profile(const char *fqname, int flags)
1295{
1296 struct aa_label *label, *new = NULL, *target = NULL;
1297 struct aa_profile *profile;
1298 struct aa_perms perms = {};
1299 const char *info = NULL;
1300 const char *auditname = fqname; /* retain leading & if stack */
1301 bool stack = flags & AA_CHANGE_STACK;
1302 struct aa_task_ctx *ctx = task_ctx(current);
1303 int error = 0;
1304 char *op;
1305 u32 request;
1306
1307 label = aa_get_current_label();
1308
1309 /*
1310 * Detect no new privs being set, and store the label it
1311 * occurred under. Ideally this would happen when nnp
1312 * is set but there isn't a good way to do that yet.
1313 *
1314 * Testing for unconfined must be done before the subset test
1315 */
1316 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1317 ctx->nnp = aa_get_label(label);
1318
1319 if (!fqname || !*fqname) {
1320 aa_put_label(label);
1321 AA_DEBUG("no profile name");
1322 return -EINVAL;
1323 }
1324
1325 if (flags & AA_CHANGE_ONEXEC) {
1326 request = AA_MAY_ONEXEC;
1327 if (stack)
1328 op = OP_STACK_ONEXEC;
1329 else
1330 op = OP_CHANGE_ONEXEC;
1331 } else {
1332 request = AA_MAY_CHANGE_PROFILE;
1333 if (stack)
1334 op = OP_STACK;
1335 else
1336 op = OP_CHANGE_PROFILE;
1337 }
1338
1339 if (*fqname == '&') {
1340 stack = true;
1341 /* don't have label_parse() do stacking */
1342 fqname++;
1343 }
1344 target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1345 if (IS_ERR(target)) {
1346 struct aa_profile *tprofile;
1347
1348 info = "label not found";
1349 error = PTR_ERR(target);
1350 target = NULL;
1351 /*
1352 * TODO: fixme using labels_profile is not right - do profile
1353 * per complain profile
1354 */
1355 if ((flags & AA_CHANGE_TEST) ||
1356 !COMPLAIN_MODE(labels_profile(label)))
1357 goto audit;
1358 /* released below */
1359 tprofile = aa_new_null_profile(labels_profile(label), false,
1360 fqname, GFP_KERNEL);
1361 if (!tprofile) {
1362 info = "failed null profile create";
1363 error = -ENOMEM;
1364 goto audit;
1365 }
1366 target = &tprofile->label;
1367 goto check;
1368 }
1369
1370 /*
1371 * self directed transitions only apply to current policy ns
1372 * TODO: currently requiring perms for stacking and straight change
1373 * stacking doesn't strictly need this. Determine how much
1374 * we want to loosen this restriction for stacking
1375 *
1376 * if (!stack) {
1377 */
1378 error = fn_for_each_in_ns(label, profile,
1379 change_profile_perms_wrapper(op, auditname,
1380 profile, target, stack,
1381 request, &perms));
1382 if (error)
1383 /* auditing done in change_profile_perms_wrapper */
1384 goto out;
1385
1386 /* } */
1387
1388check:
1389 /* check if tracing task is allowed to trace target domain */
1390 error = may_change_ptraced_domain(target, &info);
1391 if (error && !fn_for_each_in_ns(label, profile,
1392 COMPLAIN_MODE(profile)))
1393 goto audit;
1394
1395 /* TODO: add permission check to allow this
1396 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1397 * info = "not a single threaded task";
1398 * error = -EACCES;
1399 * goto audit;
1400 * }
1401 */
1402 if (flags & AA_CHANGE_TEST)
1403 goto out;
1404
1405 /* stacking is always a subset, so only check the nonstack case */
1406 if (!stack) {
1407 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1408 aa_get_label(target),
1409 aa_get_label(&profile->label));
1410 /*
1411 * no new privs prevents domain transitions that would
1412 * reduce restrictions.
1413 */
1414 if (task_no_new_privs(current) && !unconfined(label) &&
1415 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1416 /* not an apparmor denial per se, so don't log it */
1417 AA_DEBUG("no_new_privs - change_hat denied");
1418 error = -EPERM;
1419 goto out;
1420 }
1421 }
1422
1423 if (!(flags & AA_CHANGE_ONEXEC)) {
1424 /* only transition profiles in the current ns */
1425 if (stack)
1426 new = aa_label_merge(label, target, GFP_KERNEL);
1427 if (IS_ERR_OR_NULL(new)) {
1428 info = "failed to build target label";
1429 if (!new)
1430 error = -ENOMEM;
1431 else
1432 error = PTR_ERR(new);
1433 new = NULL;
1434 perms.allow = 0;
1435 goto audit;
1436 }
1437 error = aa_replace_current_label(new);
1438 } else {
1439 if (new) {
1440 aa_put_label(new);
1441 new = NULL;
1442 }
1443
1444 /* full transition will be built in exec path */
1445 error = aa_set_current_onexec(target, stack);
1446 }
1447
1448audit:
1449 error = fn_for_each_in_ns(label, profile,
1450 aa_audit_file(profile, &perms, op, request, auditname,
1451 NULL, new ? new : target,
1452 GLOBAL_ROOT_UID, info, error));
1453
1454out:
1455 aa_put_label(new);
1456 aa_put_label(target);
1457 aa_put_label(label);
1458
1459 return error;
1460}