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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/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/match.h"
28#include "include/path.h"
29#include "include/policy.h"
30#include "include/policy_ns.h"
31
32/**
33 * may_change_ptraced_domain - check if can change profile on ptraced task
34 * @to_cred: cred of task changing domain
35 * @to_label: profile to change to (NOT NULL)
36 * @info: message if there is an error
37 *
38 * Check if current is ptraced and if so if the tracing task is allowed
39 * to trace the new domain
40 *
41 * Returns: %0 or error if change not allowed
42 */
43static int may_change_ptraced_domain(const struct cred *to_cred,
44 struct aa_label *to_label,
45 const char **info)
46{
47 struct task_struct *tracer;
48 struct aa_label *tracerl = NULL;
49 const struct cred *tracer_cred = NULL;
50
51 int error = 0;
52
53 rcu_read_lock();
54 tracer = ptrace_parent(current);
55 if (tracer) {
56 /* released below */
57 tracerl = aa_get_task_label(tracer);
58 tracer_cred = get_task_cred(tracer);
59 }
60 /* not ptraced */
61 if (!tracer || unconfined(tracerl))
62 goto out;
63
64 error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label,
65 PTRACE_MODE_ATTACH);
66
67out:
68 rcu_read_unlock();
69 aa_put_label(tracerl);
70 put_cred(tracer_cred);
71
72 if (error)
73 *info = "ptrace prevents transition";
74 return error;
75}
76
77/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
78 * specifically this is an exact copy of aa_label_match except
79 * aa_compute_perms is replaced with aa_compute_fperms
80 * and policy->dfa with file->dfa
81 ****/
82/* match a profile and its associated ns component if needed
83 * Assumes visibility test has already been done.
84 * If a subns profile is not to be matched should be prescreened with
85 * visibility test.
86 */
87static inline aa_state_t match_component(struct aa_profile *profile,
88 struct aa_profile *tp,
89 bool stack, aa_state_t state)
90{
91 struct aa_ruleset *rules = list_first_entry(&profile->rules,
92 typeof(*rules), list);
93 const char *ns_name;
94
95 if (stack)
96 state = aa_dfa_match(rules->file->dfa, state, "&");
97 if (profile->ns == tp->ns)
98 return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
99
100 /* try matching with namespace name and then profile */
101 ns_name = aa_ns_name(profile->ns, tp->ns, true);
102 state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
103 state = aa_dfa_match(rules->file->dfa, state, ns_name);
104 state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
105 return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
106}
107
108/**
109 * label_compound_match - find perms for full compound label
110 * @profile: profile to find perms for
111 * @label: label to check access permissions for
112 * @stack: whether this is a stacking request
113 * @state: state to start match in
114 * @subns: whether to do permission checks on components in a subns
115 * @request: permissions to request
116 * @perms: perms struct to set
117 *
118 * Returns: 0 on success else ERROR
119 *
120 * For the label A//&B//&C this does the perm match for A//&B//&C
121 * @perms should be preinitialized with allperms OR a previous permission
122 * check to be stacked.
123 */
124static int label_compound_match(struct aa_profile *profile,
125 struct aa_label *label, bool stack,
126 aa_state_t state, bool subns, u32 request,
127 struct aa_perms *perms)
128{
129 struct aa_ruleset *rules = list_first_entry(&profile->rules,
130 typeof(*rules), list);
131 struct aa_profile *tp;
132 struct label_it i;
133 struct path_cond cond = { };
134
135 /* find first subcomponent that is visible */
136 label_for_each(i, label, tp) {
137 if (!aa_ns_visible(profile->ns, tp->ns, subns))
138 continue;
139 state = match_component(profile, tp, stack, state);
140 if (!state)
141 goto fail;
142 goto next;
143 }
144
145 /* no component visible */
146 *perms = allperms;
147 return 0;
148
149next:
150 label_for_each_cont(i, label, tp) {
151 if (!aa_ns_visible(profile->ns, tp->ns, subns))
152 continue;
153 state = aa_dfa_match(rules->file->dfa, state, "//&");
154 state = match_component(profile, tp, false, state);
155 if (!state)
156 goto fail;
157 }
158 *perms = *(aa_lookup_fperms(rules->file, state, &cond));
159 aa_apply_modes_to_perms(profile, perms);
160 if ((perms->allow & request) != request)
161 return -EACCES;
162
163 return 0;
164
165fail:
166 *perms = nullperms;
167 return -EACCES;
168}
169
170/**
171 * label_components_match - find perms for all subcomponents of a label
172 * @profile: profile to find perms for
173 * @label: label to check access permissions for
174 * @stack: whether this is a stacking request
175 * @start: state to start match in
176 * @subns: whether to do permission checks on components in a subns
177 * @request: permissions to request
178 * @perms: an initialized perms struct to add accumulation to
179 *
180 * Returns: 0 on success else ERROR
181 *
182 * For the label A//&B//&C this does the perm match for each of A and B and C
183 * @perms should be preinitialized with allperms OR a previous permission
184 * check to be stacked.
185 */
186static int label_components_match(struct aa_profile *profile,
187 struct aa_label *label, bool stack,
188 aa_state_t start, bool subns, u32 request,
189 struct aa_perms *perms)
190{
191 struct aa_ruleset *rules = list_first_entry(&profile->rules,
192 typeof(*rules), list);
193 struct aa_profile *tp;
194 struct label_it i;
195 struct aa_perms tmp;
196 struct path_cond cond = { };
197 aa_state_t state = 0;
198
199 /* find first subcomponent to test */
200 label_for_each(i, label, tp) {
201 if (!aa_ns_visible(profile->ns, tp->ns, subns))
202 continue;
203 state = match_component(profile, tp, stack, start);
204 if (!state)
205 goto fail;
206 goto next;
207 }
208
209 /* no subcomponents visible - no change in perms */
210 return 0;
211
212next:
213 tmp = *(aa_lookup_fperms(rules->file, state, &cond));
214 aa_apply_modes_to_perms(profile, &tmp);
215 aa_perms_accum(perms, &tmp);
216 label_for_each_cont(i, label, tp) {
217 if (!aa_ns_visible(profile->ns, tp->ns, subns))
218 continue;
219 state = match_component(profile, tp, stack, start);
220 if (!state)
221 goto fail;
222 tmp = *(aa_lookup_fperms(rules->file, state, &cond));
223 aa_apply_modes_to_perms(profile, &tmp);
224 aa_perms_accum(perms, &tmp);
225 }
226
227 if ((perms->allow & request) != request)
228 return -EACCES;
229
230 return 0;
231
232fail:
233 *perms = nullperms;
234 return -EACCES;
235}
236
237/**
238 * label_match - do a multi-component label match
239 * @profile: profile to match against (NOT NULL)
240 * @label: label to match (NOT NULL)
241 * @stack: whether this is a stacking request
242 * @state: state to start in
243 * @subns: whether to match subns components
244 * @request: permission request
245 * @perms: Returns computed perms (NOT NULL)
246 *
247 * Returns: the state the match finished in, may be the none matching state
248 */
249static int label_match(struct aa_profile *profile, struct aa_label *label,
250 bool stack, aa_state_t state, bool subns, u32 request,
251 struct aa_perms *perms)
252{
253 int error;
254
255 *perms = nullperms;
256 error = label_compound_match(profile, label, stack, state, subns,
257 request, perms);
258 if (!error)
259 return error;
260
261 *perms = allperms;
262 return label_components_match(profile, label, stack, state, subns,
263 request, perms);
264}
265
266/******* end TODO: dedup *****/
267
268/**
269 * change_profile_perms - find permissions for change_profile
270 * @profile: the current profile (NOT NULL)
271 * @target: label to transition to (NOT NULL)
272 * @stack: whether this is a stacking request
273 * @request: requested perms
274 * @start: state to start matching in
275 * @perms: Returns computed perms (NOT NULL)
276 *
277 *
278 * Returns: permission set
279 *
280 * currently only matches full label A//&B//&C or individual components A, B, C
281 * not arbitrary combinations. Eg. A//&B, C
282 */
283static int change_profile_perms(struct aa_profile *profile,
284 struct aa_label *target, bool stack,
285 u32 request, aa_state_t start,
286 struct aa_perms *perms)
287{
288 if (profile_unconfined(profile)) {
289 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
290 perms->audit = perms->quiet = perms->kill = 0;
291 return 0;
292 }
293
294 /* TODO: add profile in ns screening */
295 return label_match(profile, target, stack, start, true, request, perms);
296}
297
298/**
299 * aa_xattrs_match - check whether a file matches the xattrs defined in profile
300 * @bprm: binprm struct for the process to validate
301 * @profile: profile to match against (NOT NULL)
302 * @state: state to start match in
303 *
304 * Returns: number of extended attributes that matched, or < 0 on error
305 */
306static int aa_xattrs_match(const struct linux_binprm *bprm,
307 struct aa_profile *profile, aa_state_t state)
308{
309 int i;
310 struct dentry *d;
311 char *value = NULL;
312 struct aa_attachment *attach = &profile->attach;
313 int size, value_size = 0, ret = attach->xattr_count;
314
315 if (!bprm || !attach->xattr_count)
316 return 0;
317 might_sleep();
318
319 /* transition from exec match to xattr set */
320 state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
321 d = bprm->file->f_path.dentry;
322
323 for (i = 0; i < attach->xattr_count; i++) {
324 size = vfs_getxattr_alloc(&nop_mnt_idmap, d, attach->xattrs[i],
325 &value, value_size, GFP_KERNEL);
326 if (size >= 0) {
327 u32 index, perm;
328
329 /*
330 * Check the xattr presence before value. This ensure
331 * that not present xattr can be distinguished from a 0
332 * length value or rule that matches any value
333 */
334 state = aa_dfa_null_transition(attach->xmatch->dfa,
335 state);
336 /* Check xattr value */
337 state = aa_dfa_match_len(attach->xmatch->dfa, state,
338 value, size);
339 index = ACCEPT_TABLE(attach->xmatch->dfa)[state];
340 perm = attach->xmatch->perms[index].allow;
341 if (!(perm & MAY_EXEC)) {
342 ret = -EINVAL;
343 goto out;
344 }
345 }
346 /* transition to next element */
347 state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
348 if (size < 0) {
349 /*
350 * No xattr match, so verify if transition to
351 * next element was valid. IFF so the xattr
352 * was optional.
353 */
354 if (!state) {
355 ret = -EINVAL;
356 goto out;
357 }
358 /* don't count missing optional xattr as matched */
359 ret--;
360 }
361 }
362
363out:
364 kfree(value);
365 return ret;
366}
367
368/**
369 * find_attach - do attachment search for unconfined processes
370 * @bprm: binprm structure of transitioning task
371 * @ns: the current namespace (NOT NULL)
372 * @head: profile list to walk (NOT NULL)
373 * @name: to match against (NOT NULL)
374 * @info: info message if there was an error (NOT NULL)
375 *
376 * Do a linear search on the profiles in the list. There is a matching
377 * preference where an exact match is preferred over a name which uses
378 * expressions to match, and matching expressions with the greatest
379 * xmatch_len are preferred.
380 *
381 * Requires: @head not be shared or have appropriate locks held
382 *
383 * Returns: label or NULL if no match found
384 */
385static struct aa_label *find_attach(const struct linux_binprm *bprm,
386 struct aa_ns *ns, struct list_head *head,
387 const char *name, const char **info)
388{
389 int candidate_len = 0, candidate_xattrs = 0;
390 bool conflict = false;
391 struct aa_profile *profile, *candidate = NULL;
392
393 AA_BUG(!name);
394 AA_BUG(!head);
395
396 rcu_read_lock();
397restart:
398 list_for_each_entry_rcu(profile, head, base.list) {
399 struct aa_attachment *attach = &profile->attach;
400
401 if (profile->label.flags & FLAG_NULL &&
402 &profile->label == ns_unconfined(profile->ns))
403 continue;
404
405 /* Find the "best" matching profile. Profiles must
406 * match the path and extended attributes (if any)
407 * associated with the file. A more specific path
408 * match will be preferred over a less specific one,
409 * and a match with more matching extended attributes
410 * will be preferred over one with fewer. If the best
411 * match has both the same level of path specificity
412 * and the same number of matching extended attributes
413 * as another profile, signal a conflict and refuse to
414 * match.
415 */
416 if (attach->xmatch->dfa) {
417 unsigned int count;
418 aa_state_t state;
419 u32 index, perm;
420
421 state = aa_dfa_leftmatch(attach->xmatch->dfa,
422 attach->xmatch->start[AA_CLASS_XMATCH],
423 name, &count);
424 index = ACCEPT_TABLE(attach->xmatch->dfa)[state];
425 perm = attach->xmatch->perms[index].allow;
426 /* any accepting state means a valid match. */
427 if (perm & MAY_EXEC) {
428 int ret = 0;
429
430 if (count < candidate_len)
431 continue;
432
433 if (bprm && attach->xattr_count) {
434 long rev = READ_ONCE(ns->revision);
435
436 if (!aa_get_profile_not0(profile))
437 goto restart;
438 rcu_read_unlock();
439 ret = aa_xattrs_match(bprm, profile,
440 state);
441 rcu_read_lock();
442 aa_put_profile(profile);
443 if (rev !=
444 READ_ONCE(ns->revision))
445 /* policy changed */
446 goto restart;
447 /*
448 * Fail matching if the xattrs don't
449 * match
450 */
451 if (ret < 0)
452 continue;
453 }
454 /*
455 * TODO: allow for more flexible best match
456 *
457 * The new match isn't more specific
458 * than the current best match
459 */
460 if (count == candidate_len &&
461 ret <= candidate_xattrs) {
462 /* Match is equivalent, so conflict */
463 if (ret == candidate_xattrs)
464 conflict = true;
465 continue;
466 }
467
468 /* Either the same length with more matching
469 * xattrs, or a longer match
470 */
471 candidate = profile;
472 candidate_len = max(count, attach->xmatch_len);
473 candidate_xattrs = ret;
474 conflict = false;
475 }
476 } else if (!strcmp(profile->base.name, name)) {
477 /*
478 * old exact non-re match, without conditionals such
479 * as xattrs. no more searching required
480 */
481 candidate = profile;
482 goto out;
483 }
484 }
485
486 if (!candidate || conflict) {
487 if (conflict)
488 *info = "conflicting profile attachments";
489 rcu_read_unlock();
490 return NULL;
491 }
492
493out:
494 candidate = aa_get_newest_profile(candidate);
495 rcu_read_unlock();
496
497 return &candidate->label;
498}
499
500static const char *next_name(int xtype, const char *name)
501{
502 return NULL;
503}
504
505/**
506 * x_table_lookup - lookup an x transition name via transition table
507 * @profile: current profile (NOT NULL)
508 * @xindex: index into x transition table
509 * @name: returns: name tested to find label (NOT NULL)
510 *
511 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
512 */
513struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
514 const char **name)
515{
516 struct aa_ruleset *rules = list_first_entry(&profile->rules,
517 typeof(*rules), list);
518 struct aa_label *label = NULL;
519 u32 xtype = xindex & AA_X_TYPE_MASK;
520 int index = xindex & AA_X_INDEX_MASK;
521
522 AA_BUG(!name);
523
524 /* index is guaranteed to be in range, validated at load time */
525 /* TODO: move lookup parsing to unpack time so this is a straight
526 * index into the resultant label
527 */
528 for (*name = rules->file->trans.table[index]; !label && *name;
529 *name = next_name(xtype, *name)) {
530 if (xindex & AA_X_CHILD) {
531 struct aa_profile *new_profile;
532 /* release by caller */
533 new_profile = aa_find_child(profile, *name);
534 if (new_profile)
535 label = &new_profile->label;
536 continue;
537 }
538 label = aa_label_parse(&profile->label, *name, GFP_KERNEL,
539 true, false);
540 if (IS_ERR(label))
541 label = NULL;
542 }
543
544 /* released by caller */
545
546 return label;
547}
548
549/**
550 * x_to_label - get target label for a given xindex
551 * @profile: current profile (NOT NULL)
552 * @bprm: binprm structure of transitioning task
553 * @name: name to lookup (NOT NULL)
554 * @xindex: index into x transition table
555 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
556 * @info: info message if there was an error (NOT NULL)
557 *
558 * find label for a transition index
559 *
560 * Returns: refcounted label or NULL if not found available
561 */
562static struct aa_label *x_to_label(struct aa_profile *profile,
563 const struct linux_binprm *bprm,
564 const char *name, u32 xindex,
565 const char **lookupname,
566 const char **info)
567{
568 struct aa_ruleset *rules = list_first_entry(&profile->rules,
569 typeof(*rules), list);
570 struct aa_label *new = NULL;
571 struct aa_ns *ns = profile->ns;
572 u32 xtype = xindex & AA_X_TYPE_MASK;
573 const char *stack = NULL;
574
575 switch (xtype) {
576 case AA_X_NONE:
577 /* fail exec unless ix || ux fallback - handled by caller */
578 *lookupname = NULL;
579 break;
580 case AA_X_TABLE:
581 /* TODO: fix when perm mapping done at unload */
582 stack = rules->file->trans.table[xindex & AA_X_INDEX_MASK];
583 if (*stack != '&') {
584 /* released by caller */
585 new = x_table_lookup(profile, xindex, lookupname);
586 stack = NULL;
587 break;
588 }
589 fallthrough; /* to X_NAME */
590 case AA_X_NAME:
591 if (xindex & AA_X_CHILD)
592 /* released by caller */
593 new = find_attach(bprm, ns, &profile->base.profiles,
594 name, info);
595 else
596 /* released by caller */
597 new = find_attach(bprm, ns, &ns->base.profiles,
598 name, info);
599 *lookupname = name;
600 break;
601 }
602
603 if (!new) {
604 if (xindex & AA_X_INHERIT) {
605 /* (p|c|n)ix - don't change profile but do
606 * use the newest version
607 */
608 *info = "ix fallback";
609 /* no profile && no error */
610 new = aa_get_newest_label(&profile->label);
611 } else if (xindex & AA_X_UNCONFINED) {
612 new = aa_get_newest_label(ns_unconfined(profile->ns));
613 *info = "ux fallback";
614 }
615 }
616
617 if (new && stack) {
618 /* base the stack on post domain transition */
619 struct aa_label *base = new;
620
621 new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
622 if (IS_ERR(new))
623 new = NULL;
624 aa_put_label(base);
625 }
626
627 /* released by caller */
628 return new;
629}
630
631static struct aa_label *profile_transition(const struct cred *subj_cred,
632 struct aa_profile *profile,
633 const struct linux_binprm *bprm,
634 char *buffer, struct path_cond *cond,
635 bool *secure_exec)
636{
637 struct aa_ruleset *rules = list_first_entry(&profile->rules,
638 typeof(*rules), list);
639 struct aa_label *new = NULL;
640 const char *info = NULL, *name = NULL, *target = NULL;
641 aa_state_t state = rules->file->start[AA_CLASS_FILE];
642 struct aa_perms perms = {};
643 bool nonewprivs = false;
644 int error = 0;
645
646 AA_BUG(!profile);
647 AA_BUG(!bprm);
648 AA_BUG(!buffer);
649
650 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
651 &name, &info, profile->disconnected);
652 if (error) {
653 if (profile_unconfined(profile) ||
654 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
655 AA_DEBUG("name lookup ix on error");
656 error = 0;
657 new = aa_get_newest_label(&profile->label);
658 }
659 name = bprm->filename;
660 goto audit;
661 }
662
663 if (profile_unconfined(profile)) {
664 new = find_attach(bprm, profile->ns,
665 &profile->ns->base.profiles, name, &info);
666 if (new) {
667 AA_DEBUG("unconfined attached to new label");
668 return new;
669 }
670 AA_DEBUG("unconfined exec no attachment");
671 return aa_get_newest_label(&profile->label);
672 }
673
674 /* find exec permissions for name */
675 state = aa_str_perms(rules->file, state, name, cond, &perms);
676 if (perms.allow & MAY_EXEC) {
677 /* exec permission determine how to transition */
678 new = x_to_label(profile, bprm, name, perms.xindex, &target,
679 &info);
680 if (new && new->proxy == profile->label.proxy && info) {
681 /* hack ix fallback - improve how this is detected */
682 goto audit;
683 } else if (!new) {
684 error = -EACCES;
685 info = "profile transition not found";
686 /* remove MAY_EXEC to audit as failure */
687 perms.allow &= ~MAY_EXEC;
688 }
689 } else if (COMPLAIN_MODE(profile)) {
690 /* no exec permission - learning mode */
691 struct aa_profile *new_profile = NULL;
692
693 new_profile = aa_new_learning_profile(profile, false, name,
694 GFP_KERNEL);
695 if (!new_profile) {
696 error = -ENOMEM;
697 info = "could not create null profile";
698 } else {
699 error = -EACCES;
700 new = &new_profile->label;
701 }
702 perms.xindex |= AA_X_UNSAFE;
703 } else
704 /* fail exec */
705 error = -EACCES;
706
707 if (!new)
708 goto audit;
709
710
711 if (!(perms.xindex & AA_X_UNSAFE)) {
712 if (DEBUG_ON) {
713 dbg_printk("apparmor: scrubbing environment variables"
714 " for %s profile=", name);
715 aa_label_printk(new, GFP_KERNEL);
716 dbg_printk("\n");
717 }
718 *secure_exec = true;
719 }
720
721audit:
722 aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name,
723 target, new,
724 cond->uid, info, error);
725 if (!new || nonewprivs) {
726 aa_put_label(new);
727 return ERR_PTR(error);
728 }
729
730 return new;
731}
732
733static int profile_onexec(const struct cred *subj_cred,
734 struct aa_profile *profile, struct aa_label *onexec,
735 bool stack, const struct linux_binprm *bprm,
736 char *buffer, struct path_cond *cond,
737 bool *secure_exec)
738{
739 struct aa_ruleset *rules = list_first_entry(&profile->rules,
740 typeof(*rules), list);
741 aa_state_t state = rules->file->start[AA_CLASS_FILE];
742 struct aa_perms perms = {};
743 const char *xname = NULL, *info = "change_profile onexec";
744 int error = -EACCES;
745
746 AA_BUG(!profile);
747 AA_BUG(!onexec);
748 AA_BUG(!bprm);
749 AA_BUG(!buffer);
750
751 if (profile_unconfined(profile)) {
752 /* change_profile on exec already granted */
753 /*
754 * NOTE: Domain transitions from unconfined are allowed
755 * even when no_new_privs is set because this aways results
756 * in a further reduction of permissions.
757 */
758 return 0;
759 }
760
761 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
762 &xname, &info, profile->disconnected);
763 if (error) {
764 if (profile_unconfined(profile) ||
765 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
766 AA_DEBUG("name lookup ix on error");
767 error = 0;
768 }
769 xname = bprm->filename;
770 goto audit;
771 }
772
773 /* find exec permissions for name */
774 state = aa_str_perms(rules->file, state, xname, cond, &perms);
775 if (!(perms.allow & AA_MAY_ONEXEC)) {
776 info = "no change_onexec valid for executable";
777 goto audit;
778 }
779 /* test if this exec can be paired with change_profile onexec.
780 * onexec permission is linked to exec with a standard pairing
781 * exec\0change_profile
782 */
783 state = aa_dfa_null_transition(rules->file->dfa, state);
784 error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
785 state, &perms);
786 if (error) {
787 perms.allow &= ~AA_MAY_ONEXEC;
788 goto audit;
789 }
790
791 if (!(perms.xindex & AA_X_UNSAFE)) {
792 if (DEBUG_ON) {
793 dbg_printk("apparmor: scrubbing environment "
794 "variables for %s label=", xname);
795 aa_label_printk(onexec, GFP_KERNEL);
796 dbg_printk("\n");
797 }
798 *secure_exec = true;
799 }
800
801audit:
802 return aa_audit_file(subj_cred, profile, &perms, OP_EXEC,
803 AA_MAY_ONEXEC, xname,
804 NULL, onexec, cond->uid, info, error);
805}
806
807/* ensure none ns domain transitions are correctly applied with onexec */
808
809static struct aa_label *handle_onexec(const struct cred *subj_cred,
810 struct aa_label *label,
811 struct aa_label *onexec, bool stack,
812 const struct linux_binprm *bprm,
813 char *buffer, struct path_cond *cond,
814 bool *unsafe)
815{
816 struct aa_profile *profile;
817 struct aa_label *new;
818 int error;
819
820 AA_BUG(!label);
821 AA_BUG(!onexec);
822 AA_BUG(!bprm);
823 AA_BUG(!buffer);
824
825 if (!stack) {
826 error = fn_for_each_in_ns(label, profile,
827 profile_onexec(subj_cred, profile, onexec, stack,
828 bprm, buffer, cond, unsafe));
829 if (error)
830 return ERR_PTR(error);
831 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
832 aa_get_newest_label(onexec),
833 profile_transition(subj_cred, profile, bprm,
834 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(subj_cred, 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_KERNEL,
845 aa_label_merge(&profile->label, onexec,
846 GFP_KERNEL),
847 profile_transition(subj_cred, profile, bprm,
848 buffer,
849 cond, unsafe));
850 }
851
852 if (new)
853 return new;
854
855 /* TODO: get rid of GLOBAL_ROOT_UID */
856 error = fn_for_each_in_ns(label, profile,
857 aa_audit_file(subj_cred, profile, &nullperms,
858 OP_CHANGE_ONEXEC,
859 AA_MAY_ONEXEC, bprm->filename, NULL,
860 onexec, GLOBAL_ROOT_UID,
861 "failed to build target label", -ENOMEM));
862 return ERR_PTR(error);
863}
864
865/**
866 * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
867 * @bprm: binprm for the exec (NOT NULL)
868 *
869 * Returns: %0 or error on failure
870 *
871 * TODO: once the other paths are done see if we can't refactor into a fn
872 */
873int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
874{
875 struct aa_task_ctx *ctx;
876 struct aa_label *label, *new = NULL;
877 const struct cred *subj_cred;
878 struct aa_profile *profile;
879 char *buffer = NULL;
880 const char *info = NULL;
881 int error = 0;
882 bool unsafe = false;
883 vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(bprm->file),
884 file_inode(bprm->file));
885 struct path_cond cond = {
886 vfsuid_into_kuid(vfsuid),
887 file_inode(bprm->file)->i_mode
888 };
889
890 subj_cred = current_cred();
891 ctx = task_ctx(current);
892 AA_BUG(!cred_label(bprm->cred));
893 AA_BUG(!ctx);
894
895 label = aa_get_newest_label(cred_label(bprm->cred));
896
897 /*
898 * Detect no new privs being set, and store the label it
899 * occurred under. Ideally this would happen when nnp
900 * is set but there isn't a good way to do that yet.
901 *
902 * Testing for unconfined must be done before the subset test
903 */
904 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
905 !ctx->nnp)
906 ctx->nnp = aa_get_label(label);
907
908 /* buffer freed below, name is pointer into buffer */
909 buffer = aa_get_buffer(false);
910 if (!buffer) {
911 error = -ENOMEM;
912 goto done;
913 }
914
915 /* Test for onexec first as onexec override other x transitions. */
916 if (ctx->onexec)
917 new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token,
918 bprm, buffer, &cond, &unsafe);
919 else
920 new = fn_label_build(label, profile, GFP_KERNEL,
921 profile_transition(subj_cred, profile, bprm,
922 buffer,
923 &cond, &unsafe));
924
925 AA_BUG(!new);
926 if (IS_ERR(new)) {
927 error = PTR_ERR(new);
928 goto done;
929 } else if (!new) {
930 error = -ENOMEM;
931 goto done;
932 }
933
934 /* Policy has specified a domain transitions. If no_new_privs and
935 * confined ensure the transition is to confinement that is subset
936 * of the confinement when the task entered no new privs.
937 *
938 * NOTE: Domain transitions from unconfined and to stacked
939 * subsets are allowed even when no_new_privs is set because this
940 * aways results in a further reduction of permissions.
941 */
942 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
943 !unconfined(label) &&
944 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
945 error = -EPERM;
946 info = "no new privs";
947 goto audit;
948 }
949
950 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
951 /* FIXME: currently don't mediate shared state */
952 ;
953 }
954
955 if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
956 /* TODO: test needs to be profile of label to new */
957 error = may_change_ptraced_domain(bprm->cred, new, &info);
958 if (error)
959 goto audit;
960 }
961
962 if (unsafe) {
963 if (DEBUG_ON) {
964 dbg_printk("scrubbing environment variables for %s "
965 "label=", bprm->filename);
966 aa_label_printk(new, GFP_KERNEL);
967 dbg_printk("\n");
968 }
969 bprm->secureexec = 1;
970 }
971
972 if (label->proxy != new->proxy) {
973 /* when transitioning clear unsafe personality bits */
974 if (DEBUG_ON) {
975 dbg_printk("apparmor: clearing unsafe personality "
976 "bits. %s label=", bprm->filename);
977 aa_label_printk(new, GFP_KERNEL);
978 dbg_printk("\n");
979 }
980 bprm->per_clear |= PER_CLEAR_ON_SETID;
981 }
982 aa_put_label(cred_label(bprm->cred));
983 /* transfer reference, released when cred is freed */
984 set_cred_label(bprm->cred, new);
985
986done:
987 aa_put_label(label);
988 aa_put_buffer(buffer);
989
990 return error;
991
992audit:
993 error = fn_for_each(label, profile,
994 aa_audit_file(current_cred(), profile, &nullperms,
995 OP_EXEC, MAY_EXEC,
996 bprm->filename, NULL, new,
997 vfsuid_into_kuid(vfsuid), info, error));
998 aa_put_label(new);
999 goto done;
1000}
1001
1002/*
1003 * Functions for self directed profile change
1004 */
1005
1006
1007/* helper fn for change_hat
1008 *
1009 * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL
1010 */
1011static struct aa_label *build_change_hat(const struct cred *subj_cred,
1012 struct aa_profile *profile,
1013 const char *name, bool sibling)
1014{
1015 struct aa_profile *root, *hat = NULL;
1016 const char *info = NULL;
1017 int error = 0;
1018
1019 if (sibling && PROFILE_IS_HAT(profile)) {
1020 root = aa_get_profile_rcu(&profile->parent);
1021 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1022 root = aa_get_profile(profile);
1023 } else {
1024 info = "conflicting target types";
1025 error = -EPERM;
1026 goto audit;
1027 }
1028
1029 hat = aa_find_child(root, name);
1030 if (!hat) {
1031 error = -ENOENT;
1032 if (COMPLAIN_MODE(profile)) {
1033 hat = aa_new_learning_profile(profile, true, name,
1034 GFP_KERNEL);
1035 if (!hat) {
1036 info = "failed null profile create";
1037 error = -ENOMEM;
1038 }
1039 }
1040 }
1041 aa_put_profile(root);
1042
1043audit:
1044 aa_audit_file(subj_cred, profile, &nullperms, OP_CHANGE_HAT,
1045 AA_MAY_CHANGEHAT,
1046 name, hat ? hat->base.hname : NULL,
1047 hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1048 error);
1049 if (!hat || (error && error != -ENOENT))
1050 return ERR_PTR(error);
1051 /* if hat && error - complain mode, already audited and we adjust for
1052 * complain mode allow by returning hat->label
1053 */
1054 return &hat->label;
1055}
1056
1057/* helper fn for changing into a hat
1058 *
1059 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1060 */
1061static struct aa_label *change_hat(const struct cred *subj_cred,
1062 struct aa_label *label, const char *hats[],
1063 int count, int flags)
1064{
1065 struct aa_profile *profile, *root, *hat = NULL;
1066 struct aa_label *new;
1067 struct label_it it;
1068 bool sibling = false;
1069 const char *name, *info = NULL;
1070 int i, error;
1071
1072 AA_BUG(!label);
1073 AA_BUG(!hats);
1074 AA_BUG(count < 1);
1075
1076 if (PROFILE_IS_HAT(labels_profile(label)))
1077 sibling = true;
1078
1079 /*find first matching hat */
1080 for (i = 0; i < count && !hat; i++) {
1081 name = hats[i];
1082 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1083 if (sibling && PROFILE_IS_HAT(profile)) {
1084 root = aa_get_profile_rcu(&profile->parent);
1085 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1086 root = aa_get_profile(profile);
1087 } else { /* conflicting change type */
1088 info = "conflicting targets types";
1089 error = -EPERM;
1090 goto fail;
1091 }
1092 hat = aa_find_child(root, name);
1093 aa_put_profile(root);
1094 if (!hat) {
1095 if (!COMPLAIN_MODE(profile))
1096 goto outer_continue;
1097 /* complain mode succeed as if hat */
1098 } else if (!PROFILE_IS_HAT(hat)) {
1099 info = "target not hat";
1100 error = -EPERM;
1101 aa_put_profile(hat);
1102 goto fail;
1103 }
1104 aa_put_profile(hat);
1105 }
1106 /* found a hat for all profiles in ns */
1107 goto build;
1108outer_continue:
1109 ;
1110 }
1111 /* no hats that match, find appropriate error
1112 *
1113 * In complain mode audit of the failure is based off of the first
1114 * hat supplied. This is done due how userspace interacts with
1115 * change_hat.
1116 */
1117 name = NULL;
1118 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1119 if (!list_empty(&profile->base.profiles)) {
1120 info = "hat not found";
1121 error = -ENOENT;
1122 goto fail;
1123 }
1124 }
1125 info = "no hats defined";
1126 error = -ECHILD;
1127
1128fail:
1129 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1130 /*
1131 * no target as it has failed to be found or built
1132 *
1133 * change_hat uses probing and should not log failures
1134 * related to missing hats
1135 */
1136 /* TODO: get rid of GLOBAL_ROOT_UID */
1137 if (count > 1 || COMPLAIN_MODE(profile)) {
1138 aa_audit_file(subj_cred, profile, &nullperms,
1139 OP_CHANGE_HAT,
1140 AA_MAY_CHANGEHAT, name, NULL, NULL,
1141 GLOBAL_ROOT_UID, info, error);
1142 }
1143 }
1144 return ERR_PTR(error);
1145
1146build:
1147 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1148 build_change_hat(subj_cred, profile, name,
1149 sibling),
1150 aa_get_label(&profile->label));
1151 if (!new) {
1152 info = "label build failed";
1153 error = -ENOMEM;
1154 goto fail;
1155 } /* else if (IS_ERR) build_change_hat has logged error so return new */
1156
1157 return new;
1158}
1159
1160/**
1161 * aa_change_hat - change hat to/from subprofile
1162 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1163 * @count: number of hat names in @hats
1164 * @token: magic value to validate the hat change
1165 * @flags: flags affecting behavior of the change
1166 *
1167 * Returns %0 on success, error otherwise.
1168 *
1169 * Change to the first profile specified in @hats that exists, and store
1170 * the @hat_magic in the current task context. If the count == 0 and the
1171 * @token matches that stored in the current task context, return to the
1172 * top level profile.
1173 *
1174 * change_hat only applies to profiles in the current ns, and each profile
1175 * in the ns must make the same transition otherwise change_hat will fail.
1176 */
1177int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1178{
1179 const struct cred *subj_cred;
1180 struct aa_task_ctx *ctx = task_ctx(current);
1181 struct aa_label *label, *previous, *new = NULL, *target = NULL;
1182 struct aa_profile *profile;
1183 struct aa_perms perms = {};
1184 const char *info = NULL;
1185 int error = 0;
1186
1187 /* released below */
1188 subj_cred = get_current_cred();
1189 label = aa_get_newest_cred_label(subj_cred);
1190 previous = aa_get_newest_label(ctx->previous);
1191
1192 /*
1193 * Detect no new privs being set, and store the label it
1194 * occurred under. Ideally this would happen when nnp
1195 * is set but there isn't a good way to do that yet.
1196 *
1197 * Testing for unconfined must be done before the subset test
1198 */
1199 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1200 ctx->nnp = aa_get_label(label);
1201
1202 if (unconfined(label)) {
1203 info = "unconfined can not change_hat";
1204 error = -EPERM;
1205 goto fail;
1206 }
1207
1208 if (count) {
1209 new = change_hat(subj_cred, label, hats, count, flags);
1210 AA_BUG(!new);
1211 if (IS_ERR(new)) {
1212 error = PTR_ERR(new);
1213 new = NULL;
1214 /* already audited */
1215 goto out;
1216 }
1217
1218 /* target cred is the same as current except new label */
1219 error = may_change_ptraced_domain(subj_cred, new, &info);
1220 if (error)
1221 goto fail;
1222
1223 /*
1224 * no new privs prevents domain transitions that would
1225 * reduce restrictions.
1226 */
1227 if (task_no_new_privs(current) && !unconfined(label) &&
1228 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1229 /* not an apparmor denial per se, so don't log it */
1230 AA_DEBUG("no_new_privs - change_hat denied");
1231 error = -EPERM;
1232 goto out;
1233 }
1234
1235 if (flags & AA_CHANGE_TEST)
1236 goto out;
1237
1238 target = new;
1239 error = aa_set_current_hat(new, token);
1240 if (error == -EACCES)
1241 /* kill task in case of brute force attacks */
1242 goto kill;
1243 } else if (previous && !(flags & AA_CHANGE_TEST)) {
1244 /*
1245 * no new privs prevents domain transitions that would
1246 * reduce restrictions.
1247 */
1248 if (task_no_new_privs(current) && !unconfined(label) &&
1249 !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
1250 /* not an apparmor denial per se, so don't log it */
1251 AA_DEBUG("no_new_privs - change_hat denied");
1252 error = -EPERM;
1253 goto out;
1254 }
1255
1256 /* Return to saved label. Kill task if restore fails
1257 * to avoid brute force attacks
1258 */
1259 target = previous;
1260 error = aa_restore_previous_label(token);
1261 if (error) {
1262 if (error == -EACCES)
1263 goto kill;
1264 goto fail;
1265 }
1266 } /* else ignore @flags && restores when there is no saved profile */
1267
1268out:
1269 aa_put_label(new);
1270 aa_put_label(previous);
1271 aa_put_label(label);
1272 put_cred(subj_cred);
1273
1274 return error;
1275
1276kill:
1277 info = "failed token match";
1278 perms.kill = AA_MAY_CHANGEHAT;
1279
1280fail:
1281 fn_for_each_in_ns(label, profile,
1282 aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT,
1283 AA_MAY_CHANGEHAT, NULL, NULL, target,
1284 GLOBAL_ROOT_UID, info, error));
1285
1286 goto out;
1287}
1288
1289
1290static int change_profile_perms_wrapper(const char *op, const char *name,
1291 const struct cred *subj_cred,
1292 struct aa_profile *profile,
1293 struct aa_label *target, bool stack,
1294 u32 request, struct aa_perms *perms)
1295{
1296 struct aa_ruleset *rules = list_first_entry(&profile->rules,
1297 typeof(*rules), list);
1298 const char *info = NULL;
1299 int error = 0;
1300
1301 if (!error)
1302 error = change_profile_perms(profile, target, stack, request,
1303 rules->file->start[AA_CLASS_FILE],
1304 perms);
1305 if (error)
1306 error = aa_audit_file(subj_cred, profile, perms, op, request,
1307 name,
1308 NULL, target, GLOBAL_ROOT_UID, info,
1309 error);
1310
1311 return error;
1312}
1313
1314static const char *stack_msg = "change_profile unprivileged unconfined converted to stacking";
1315
1316/**
1317 * aa_change_profile - perform a one-way profile transition
1318 * @fqname: name of profile may include namespace (NOT NULL)
1319 * @flags: flags affecting change behavior
1320 *
1321 * Change to new profile @name. Unlike with hats, there is no way
1322 * to change back. If @name isn't specified the current profile name is
1323 * used.
1324 * If @onexec then the transition is delayed until
1325 * the next exec.
1326 *
1327 * Returns %0 on success, error otherwise.
1328 */
1329int aa_change_profile(const char *fqname, int flags)
1330{
1331 struct aa_label *label, *new = NULL, *target = NULL;
1332 struct aa_profile *profile;
1333 struct aa_perms perms = {};
1334 const char *info = NULL;
1335 const char *auditname = fqname; /* retain leading & if stack */
1336 bool stack = flags & AA_CHANGE_STACK;
1337 struct aa_task_ctx *ctx = task_ctx(current);
1338 const struct cred *subj_cred = get_current_cred();
1339 int error = 0;
1340 char *op;
1341 u32 request;
1342
1343 label = aa_get_current_label();
1344
1345 /*
1346 * Detect no new privs being set, and store the label it
1347 * occurred under. Ideally this would happen when nnp
1348 * is set but there isn't a good way to do that yet.
1349 *
1350 * Testing for unconfined must be done before the subset test
1351 */
1352 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1353 ctx->nnp = aa_get_label(label);
1354
1355 if (!fqname || !*fqname) {
1356 aa_put_label(label);
1357 AA_DEBUG("no profile name");
1358 return -EINVAL;
1359 }
1360
1361 if (flags & AA_CHANGE_ONEXEC) {
1362 request = AA_MAY_ONEXEC;
1363 if (stack)
1364 op = OP_STACK_ONEXEC;
1365 else
1366 op = OP_CHANGE_ONEXEC;
1367 } else {
1368 request = AA_MAY_CHANGE_PROFILE;
1369 if (stack)
1370 op = OP_STACK;
1371 else
1372 op = OP_CHANGE_PROFILE;
1373 }
1374
1375 /* This should move to a per profile test. Requires pushing build
1376 * into callback
1377 */
1378 if (!stack && unconfined(label) &&
1379 label == &labels_ns(label)->unconfined->label &&
1380 aa_unprivileged_unconfined_restricted &&
1381 /* TODO: refactor so this check is a fn */
1382 cap_capable(current_cred(), &init_user_ns, CAP_MAC_OVERRIDE,
1383 CAP_OPT_NOAUDIT)) {
1384 /* regardless of the request in this case apparmor
1385 * stacks against unconfined so admin set policy can't be
1386 * by-passed
1387 */
1388 stack = true;
1389 perms.audit = request;
1390 (void) fn_for_each_in_ns(label, profile,
1391 aa_audit_file(subj_cred, profile, &perms, op,
1392 request, auditname, NULL, target,
1393 GLOBAL_ROOT_UID, stack_msg, 0));
1394 perms.audit = 0;
1395 }
1396
1397 if (*fqname == '&') {
1398 stack = true;
1399 /* don't have label_parse() do stacking */
1400 fqname++;
1401 }
1402 target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1403 if (IS_ERR(target)) {
1404 struct aa_profile *tprofile;
1405
1406 info = "label not found";
1407 error = PTR_ERR(target);
1408 target = NULL;
1409 /*
1410 * TODO: fixme using labels_profile is not right - do profile
1411 * per complain profile
1412 */
1413 if ((flags & AA_CHANGE_TEST) ||
1414 !COMPLAIN_MODE(labels_profile(label)))
1415 goto audit;
1416 /* released below */
1417 tprofile = aa_new_learning_profile(labels_profile(label), false,
1418 fqname, GFP_KERNEL);
1419 if (!tprofile) {
1420 info = "failed null profile create";
1421 error = -ENOMEM;
1422 goto audit;
1423 }
1424 target = &tprofile->label;
1425 goto check;
1426 }
1427
1428 /*
1429 * self directed transitions only apply to current policy ns
1430 * TODO: currently requiring perms for stacking and straight change
1431 * stacking doesn't strictly need this. Determine how much
1432 * we want to loosen this restriction for stacking
1433 *
1434 * if (!stack) {
1435 */
1436 error = fn_for_each_in_ns(label, profile,
1437 change_profile_perms_wrapper(op, auditname,
1438 subj_cred,
1439 profile, target, stack,
1440 request, &perms));
1441 if (error)
1442 /* auditing done in change_profile_perms_wrapper */
1443 goto out;
1444
1445 /* } */
1446
1447check:
1448 /* check if tracing task is allowed to trace target domain */
1449 error = may_change_ptraced_domain(subj_cred, target, &info);
1450 if (error && !fn_for_each_in_ns(label, profile,
1451 COMPLAIN_MODE(profile)))
1452 goto audit;
1453
1454 /* TODO: add permission check to allow this
1455 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1456 * info = "not a single threaded task";
1457 * error = -EACCES;
1458 * goto audit;
1459 * }
1460 */
1461 if (flags & AA_CHANGE_TEST)
1462 goto out;
1463
1464 /* stacking is always a subset, so only check the nonstack case */
1465 if (!stack) {
1466 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1467 aa_get_label(target),
1468 aa_get_label(&profile->label));
1469 /*
1470 * no new privs prevents domain transitions that would
1471 * reduce restrictions.
1472 */
1473 if (task_no_new_privs(current) && !unconfined(label) &&
1474 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1475 /* not an apparmor denial per se, so don't log it */
1476 AA_DEBUG("no_new_privs - change_hat denied");
1477 error = -EPERM;
1478 goto out;
1479 }
1480 }
1481
1482 if (!(flags & AA_CHANGE_ONEXEC)) {
1483 /* only transition profiles in the current ns */
1484 if (stack)
1485 new = aa_label_merge(label, target, GFP_KERNEL);
1486 if (IS_ERR_OR_NULL(new)) {
1487 info = "failed to build target label";
1488 if (!new)
1489 error = -ENOMEM;
1490 else
1491 error = PTR_ERR(new);
1492 new = NULL;
1493 perms.allow = 0;
1494 goto audit;
1495 }
1496 error = aa_replace_current_label(new);
1497 } else {
1498 if (new) {
1499 aa_put_label(new);
1500 new = NULL;
1501 }
1502
1503 /* full transition will be built in exec path */
1504 aa_set_current_onexec(target, stack);
1505 }
1506
1507audit:
1508 error = fn_for_each_in_ns(label, profile,
1509 aa_audit_file(subj_cred,
1510 profile, &perms, op, request, auditname,
1511 NULL, new ? new : target,
1512 GLOBAL_ROOT_UID, info, error));
1513
1514out:
1515 aa_put_label(new);
1516 aa_put_label(target);
1517 aa_put_label(label);
1518 put_cred(subj_cred);
1519
1520 return error;
1521}