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1/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor policy attachment and domain transitions
5 *
6 * Copyright (C) 2002-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 */
14
15#include <linux/errno.h>
16#include <linux/fdtable.h>
17#include <linux/file.h>
18#include <linux/mount.h>
19#include <linux/syscalls.h>
20#include <linux/tracehook.h>
21#include <linux/personality.h>
22#include <linux/xattr.h>
23
24#include "include/audit.h"
25#include "include/apparmorfs.h"
26#include "include/cred.h"
27#include "include/domain.h"
28#include "include/file.h"
29#include "include/ipc.h"
30#include "include/match.h"
31#include "include/path.h"
32#include "include/policy.h"
33#include "include/policy_ns.h"
34
35/**
36 * aa_free_domain_entries - free entries in a domain table
37 * @domain: the domain table to free (MAYBE NULL)
38 */
39void aa_free_domain_entries(struct aa_domain *domain)
40{
41 int i;
42 if (domain) {
43 if (!domain->table)
44 return;
45
46 for (i = 0; i < domain->size; i++)
47 kzfree(domain->table[i]);
48 kzfree(domain->table);
49 domain->table = NULL;
50 }
51}
52
53/**
54 * may_change_ptraced_domain - check if can change profile on ptraced task
55 * @to_label: profile to change to (NOT NULL)
56 * @info: message if there is an error
57 *
58 * Check if current is ptraced and if so if the tracing task is allowed
59 * to trace the new domain
60 *
61 * Returns: %0 or error if change not allowed
62 */
63static int may_change_ptraced_domain(struct aa_label *to_label,
64 const char **info)
65{
66 struct task_struct *tracer;
67 struct aa_label *tracerl = NULL;
68 int error = 0;
69
70 rcu_read_lock();
71 tracer = ptrace_parent(current);
72 if (tracer)
73 /* released below */
74 tracerl = aa_get_task_label(tracer);
75
76 /* not ptraced */
77 if (!tracer || unconfined(tracerl))
78 goto out;
79
80 error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH);
81
82out:
83 rcu_read_unlock();
84 aa_put_label(tracerl);
85
86 if (error)
87 *info = "ptrace prevents transition";
88 return error;
89}
90
91/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
92 * specifically this is an exact copy of aa_label_match except
93 * aa_compute_perms is replaced with aa_compute_fperms
94 * and policy.dfa with file.dfa
95 ****/
96/* match a profile and its associated ns component if needed
97 * Assumes visibility test has already been done.
98 * If a subns profile is not to be matched should be prescreened with
99 * visibility test.
100 */
101static inline unsigned int match_component(struct aa_profile *profile,
102 struct aa_profile *tp,
103 bool stack, unsigned int state)
104{
105 const char *ns_name;
106
107 if (stack)
108 state = aa_dfa_match(profile->file.dfa, state, "&");
109 if (profile->ns == tp->ns)
110 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
111
112 /* try matching with namespace name and then profile */
113 ns_name = aa_ns_name(profile->ns, tp->ns, true);
114 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
115 state = aa_dfa_match(profile->file.dfa, state, ns_name);
116 state = aa_dfa_match_len(profile->file.dfa, state, ":", 1);
117 return aa_dfa_match(profile->file.dfa, state, tp->base.hname);
118}
119
120/**
121 * label_compound_match - find perms for full compound label
122 * @profile: profile to find perms for
123 * @label: label to check access permissions for
124 * @stack: whether this is a stacking request
125 * @start: state to start match in
126 * @subns: whether to do permission checks on components in a subns
127 * @request: permissions to request
128 * @perms: perms struct to set
129 *
130 * Returns: 0 on success else ERROR
131 *
132 * For the label A//&B//&C this does the perm match for A//&B//&C
133 * @perms should be preinitialized with allperms OR a previous permission
134 * check to be stacked.
135 */
136static int label_compound_match(struct aa_profile *profile,
137 struct aa_label *label, bool stack,
138 unsigned int state, bool subns, u32 request,
139 struct aa_perms *perms)
140{
141 struct aa_profile *tp;
142 struct label_it i;
143 struct path_cond cond = { };
144
145 /* find first subcomponent that is visible */
146 label_for_each(i, label, tp) {
147 if (!aa_ns_visible(profile->ns, tp->ns, subns))
148 continue;
149 state = match_component(profile, tp, stack, state);
150 if (!state)
151 goto fail;
152 goto next;
153 }
154
155 /* no component visible */
156 *perms = allperms;
157 return 0;
158
159next:
160 label_for_each_cont(i, label, tp) {
161 if (!aa_ns_visible(profile->ns, tp->ns, subns))
162 continue;
163 state = aa_dfa_match(profile->file.dfa, state, "//&");
164 state = match_component(profile, tp, false, state);
165 if (!state)
166 goto fail;
167 }
168 *perms = aa_compute_fperms(profile->file.dfa, state, &cond);
169 aa_apply_modes_to_perms(profile, perms);
170 if ((perms->allow & request) != request)
171 return -EACCES;
172
173 return 0;
174
175fail:
176 *perms = nullperms;
177 return -EACCES;
178}
179
180/**
181 * label_components_match - find perms for all subcomponents of a label
182 * @profile: profile to find perms for
183 * @label: label to check access permissions for
184 * @stack: whether this is a stacking request
185 * @start: state to start match in
186 * @subns: whether to do permission checks on components in a subns
187 * @request: permissions to request
188 * @perms: an initialized perms struct to add accumulation to
189 *
190 * Returns: 0 on success else ERROR
191 *
192 * For the label A//&B//&C this does the perm match for each of A and B and C
193 * @perms should be preinitialized with allperms OR a previous permission
194 * check to be stacked.
195 */
196static int label_components_match(struct aa_profile *profile,
197 struct aa_label *label, bool stack,
198 unsigned int start, bool subns, u32 request,
199 struct aa_perms *perms)
200{
201 struct aa_profile *tp;
202 struct label_it i;
203 struct aa_perms tmp;
204 struct path_cond cond = { };
205 unsigned int state = 0;
206
207 /* find first subcomponent to test */
208 label_for_each(i, label, tp) {
209 if (!aa_ns_visible(profile->ns, tp->ns, subns))
210 continue;
211 state = match_component(profile, tp, stack, start);
212 if (!state)
213 goto fail;
214 goto next;
215 }
216
217 /* no subcomponents visible - no change in perms */
218 return 0;
219
220next:
221 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
222 aa_apply_modes_to_perms(profile, &tmp);
223 aa_perms_accum(perms, &tmp);
224 label_for_each_cont(i, label, tp) {
225 if (!aa_ns_visible(profile->ns, tp->ns, subns))
226 continue;
227 state = match_component(profile, tp, stack, start);
228 if (!state)
229 goto fail;
230 tmp = aa_compute_fperms(profile->file.dfa, state, &cond);
231 aa_apply_modes_to_perms(profile, &tmp);
232 aa_perms_accum(perms, &tmp);
233 }
234
235 if ((perms->allow & request) != request)
236 return -EACCES;
237
238 return 0;
239
240fail:
241 *perms = nullperms;
242 return -EACCES;
243}
244
245/**
246 * label_match - do a multi-component label match
247 * @profile: profile to match against (NOT NULL)
248 * @label: label to match (NOT NULL)
249 * @stack: whether this is a stacking request
250 * @state: state to start in
251 * @subns: whether to match subns components
252 * @request: permission request
253 * @perms: Returns computed perms (NOT NULL)
254 *
255 * Returns: the state the match finished in, may be the none matching state
256 */
257static int label_match(struct aa_profile *profile, struct aa_label *label,
258 bool stack, unsigned int state, bool subns, u32 request,
259 struct aa_perms *perms)
260{
261 int error;
262
263 *perms = nullperms;
264 error = label_compound_match(profile, label, stack, state, subns,
265 request, perms);
266 if (!error)
267 return error;
268
269 *perms = allperms;
270 return label_components_match(profile, label, stack, state, subns,
271 request, perms);
272}
273
274/******* end TODO: dedup *****/
275
276/**
277 * change_profile_perms - find permissions for change_profile
278 * @profile: the current profile (NOT NULL)
279 * @target: label to transition to (NOT NULL)
280 * @stack: whether this is a stacking request
281 * @request: requested perms
282 * @start: state to start matching in
283 *
284 *
285 * Returns: permission set
286 *
287 * currently only matches full label A//&B//&C or individual components A, B, C
288 * not arbitrary combinations. Eg. A//&B, C
289 */
290static int change_profile_perms(struct aa_profile *profile,
291 struct aa_label *target, bool stack,
292 u32 request, unsigned int start,
293 struct aa_perms *perms)
294{
295 if (profile_unconfined(profile)) {
296 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
297 perms->audit = perms->quiet = perms->kill = 0;
298 return 0;
299 }
300
301 /* TODO: add profile in ns screening */
302 return label_match(profile, target, stack, start, true, request, perms);
303}
304
305/**
306 * aa_xattrs_match - check whether a file matches the xattrs defined in profile
307 * @bprm: binprm struct for the process to validate
308 * @profile: profile to match against (NOT NULL)
309 * @state: state to start match in
310 *
311 * Returns: number of extended attributes that matched, or < 0 on error
312 */
313static int aa_xattrs_match(const struct linux_binprm *bprm,
314 struct aa_profile *profile, unsigned int state)
315{
316 int i;
317 ssize_t size;
318 struct dentry *d;
319 char *value = NULL;
320 int value_size = 0, ret = profile->xattr_count;
321
322 if (!bprm || !profile->xattr_count)
323 return 0;
324
325 /* transition from exec match to xattr set */
326 state = aa_dfa_null_transition(profile->xmatch, state);
327
328 d = bprm->file->f_path.dentry;
329
330 for (i = 0; i < profile->xattr_count; i++) {
331 size = vfs_getxattr_alloc(d, profile->xattrs[i], &value,
332 value_size, GFP_KERNEL);
333 if (size >= 0) {
334 u32 perm;
335
336 /* Check the xattr value, not just presence */
337 state = aa_dfa_match_len(profile->xmatch, state, value,
338 size);
339 perm = dfa_user_allow(profile->xmatch, state);
340 if (!(perm & MAY_EXEC)) {
341 ret = -EINVAL;
342 goto out;
343 }
344 }
345 /* transition to next element */
346 state = aa_dfa_null_transition(profile->xmatch, state);
347 if (size < 0) {
348 /*
349 * No xattr match, so verify if transition to
350 * next element was valid. IFF so the xattr
351 * was optional.
352 */
353 if (!state) {
354 ret = -EINVAL;
355 goto out;
356 }
357 /* don't count missing optional xattr as matched */
358 ret--;
359 }
360 }
361
362out:
363 kfree(value);
364 return ret;
365}
366
367/**
368 * __attach_match_ - find an attachment match
369 * @bprm - binprm structure of transitioning task
370 * @name - to match against (NOT NULL)
371 * @head - profile list to walk (NOT NULL)
372 * @info - info message if there was an error (NOT NULL)
373 *
374 * Do a linear search on the profiles in the list. There is a matching
375 * preference where an exact match is preferred over a name which uses
376 * expressions to match, and matching expressions with the greatest
377 * xmatch_len are preferred.
378 *
379 * Requires: @head not be shared or have appropriate locks held
380 *
381 * Returns: profile or NULL if no match found
382 */
383static struct aa_profile *__attach_match(const struct linux_binprm *bprm,
384 const char *name,
385 struct list_head *head,
386 const char **info)
387{
388 int candidate_len = 0, candidate_xattrs = 0;
389 bool conflict = false;
390 struct aa_profile *profile, *candidate = NULL;
391
392 AA_BUG(!name);
393 AA_BUG(!head);
394
395 list_for_each_entry_rcu(profile, head, base.list) {
396 if (profile->label.flags & FLAG_NULL &&
397 &profile->label == ns_unconfined(profile->ns))
398 continue;
399
400 /* Find the "best" matching profile. Profiles must
401 * match the path and extended attributes (if any)
402 * associated with the file. A more specific path
403 * match will be preferred over a less specific one,
404 * and a match with more matching extended attributes
405 * will be preferred over one with fewer. If the best
406 * match has both the same level of path specificity
407 * and the same number of matching extended attributes
408 * as another profile, signal a conflict and refuse to
409 * match.
410 */
411 if (profile->xmatch) {
412 unsigned int state, count;
413 u32 perm;
414
415 state = aa_dfa_leftmatch(profile->xmatch, DFA_START,
416 name, &count);
417 perm = dfa_user_allow(profile->xmatch, state);
418 /* any accepting state means a valid match. */
419 if (perm & MAY_EXEC) {
420 int ret;
421
422 if (count < candidate_len)
423 continue;
424
425 ret = aa_xattrs_match(bprm, profile, state);
426 /* Fail matching if the xattrs don't match */
427 if (ret < 0)
428 continue;
429
430 /*
431 * TODO: allow for more flexible best match
432 *
433 * The new match isn't more specific
434 * than the current best match
435 */
436 if (count == candidate_len &&
437 ret <= candidate_xattrs) {
438 /* Match is equivalent, so conflict */
439 if (ret == candidate_xattrs)
440 conflict = true;
441 continue;
442 }
443
444 /* Either the same length with more matching
445 * xattrs, or a longer match
446 */
447 candidate = profile;
448 candidate_len = profile->xmatch_len;
449 candidate_xattrs = ret;
450 conflict = false;
451 }
452 } else if (!strcmp(profile->base.name, name))
453 /*
454 * old exact non-re match, without conditionals such
455 * as xattrs. no more searching required
456 */
457 return profile;
458 }
459
460 if (conflict) {
461 *info = "conflicting profile attachments";
462 return NULL;
463 }
464
465 return candidate;
466}
467
468/**
469 * find_attach - do attachment search for unconfined processes
470 * @bprm - binprm structure of transitioning task
471 * @ns: the current namespace (NOT NULL)
472 * @list: list to search (NOT NULL)
473 * @name: the executable name to match against (NOT NULL)
474 * @info: info message if there was an error
475 *
476 * Returns: label or NULL if no match found
477 */
478static struct aa_label *find_attach(const struct linux_binprm *bprm,
479 struct aa_ns *ns, struct list_head *list,
480 const char *name, const char **info)
481{
482 struct aa_profile *profile;
483
484 rcu_read_lock();
485 profile = aa_get_profile(__attach_match(bprm, name, list, info));
486 rcu_read_unlock();
487
488 return profile ? &profile->label : NULL;
489}
490
491static const char *next_name(int xtype, const char *name)
492{
493 return NULL;
494}
495
496/**
497 * x_table_lookup - lookup an x transition name via transition table
498 * @profile: current profile (NOT NULL)
499 * @xindex: index into x transition table
500 * @name: returns: name tested to find label (NOT NULL)
501 *
502 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
503 */
504struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
505 const char **name)
506{
507 struct aa_label *label = NULL;
508 u32 xtype = xindex & AA_X_TYPE_MASK;
509 int index = xindex & AA_X_INDEX_MASK;
510
511 AA_BUG(!name);
512
513 /* index is guaranteed to be in range, validated at load time */
514 /* TODO: move lookup parsing to unpack time so this is a straight
515 * index into the resultant label
516 */
517 for (*name = profile->file.trans.table[index]; !label && *name;
518 *name = next_name(xtype, *name)) {
519 if (xindex & AA_X_CHILD) {
520 struct aa_profile *new_profile;
521 /* release by caller */
522 new_profile = aa_find_child(profile, *name);
523 if (new_profile)
524 label = &new_profile->label;
525 continue;
526 }
527 label = aa_label_parse(&profile->label, *name, GFP_ATOMIC,
528 true, false);
529 if (IS_ERR(label))
530 label = NULL;
531 }
532
533 /* released by caller */
534
535 return label;
536}
537
538/**
539 * x_to_label - get target label for a given xindex
540 * @profile: current profile (NOT NULL)
541 * @bprm: binprm structure of transitioning task
542 * @name: name to lookup (NOT NULL)
543 * @xindex: index into x transition table
544 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
545 *
546 * find label for a transition index
547 *
548 * Returns: refcounted label or NULL if not found available
549 */
550static struct aa_label *x_to_label(struct aa_profile *profile,
551 const struct linux_binprm *bprm,
552 const char *name, u32 xindex,
553 const char **lookupname,
554 const char **info)
555{
556 struct aa_label *new = NULL;
557 struct aa_ns *ns = profile->ns;
558 u32 xtype = xindex & AA_X_TYPE_MASK;
559 const char *stack = NULL;
560
561 switch (xtype) {
562 case AA_X_NONE:
563 /* fail exec unless ix || ux fallback - handled by caller */
564 *lookupname = NULL;
565 break;
566 case AA_X_TABLE:
567 /* TODO: fix when perm mapping done at unload */
568 stack = profile->file.trans.table[xindex & AA_X_INDEX_MASK];
569 if (*stack != '&') {
570 /* released by caller */
571 new = x_table_lookup(profile, xindex, lookupname);
572 stack = NULL;
573 break;
574 }
575 /* fall through to X_NAME */
576 case AA_X_NAME:
577 if (xindex & AA_X_CHILD)
578 /* released by caller */
579 new = find_attach(bprm, ns, &profile->base.profiles,
580 name, info);
581 else
582 /* released by caller */
583 new = find_attach(bprm, ns, &ns->base.profiles,
584 name, info);
585 *lookupname = name;
586 break;
587 }
588
589 if (!new) {
590 if (xindex & AA_X_INHERIT) {
591 /* (p|c|n)ix - don't change profile but do
592 * use the newest version
593 */
594 *info = "ix fallback";
595 /* no profile && no error */
596 new = aa_get_newest_label(&profile->label);
597 } else if (xindex & AA_X_UNCONFINED) {
598 new = aa_get_newest_label(ns_unconfined(profile->ns));
599 *info = "ux fallback";
600 }
601 }
602
603 if (new && stack) {
604 /* base the stack on post domain transition */
605 struct aa_label *base = new;
606
607 new = aa_label_parse(base, stack, GFP_ATOMIC, true, false);
608 if (IS_ERR(new))
609 new = NULL;
610 aa_put_label(base);
611 }
612
613 /* released by caller */
614 return new;
615}
616
617static struct aa_label *profile_transition(struct aa_profile *profile,
618 const struct linux_binprm *bprm,
619 char *buffer, struct path_cond *cond,
620 bool *secure_exec)
621{
622 struct aa_label *new = NULL;
623 struct aa_profile *component;
624 struct label_it i;
625 const char *info = NULL, *name = NULL, *target = NULL;
626 unsigned int state = profile->file.start;
627 struct aa_perms perms = {};
628 bool nonewprivs = false;
629 int error = 0;
630
631 AA_BUG(!profile);
632 AA_BUG(!bprm);
633 AA_BUG(!buffer);
634
635 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
636 &name, &info, profile->disconnected);
637 if (error) {
638 if (profile_unconfined(profile) ||
639 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
640 AA_DEBUG("name lookup ix on error");
641 error = 0;
642 new = aa_get_newest_label(&profile->label);
643 }
644 name = bprm->filename;
645 goto audit;
646 }
647
648 if (profile_unconfined(profile)) {
649 new = find_attach(bprm, profile->ns,
650 &profile->ns->base.profiles, name, &info);
651 if (new) {
652 AA_DEBUG("unconfined attached to new label");
653 return new;
654 }
655 AA_DEBUG("unconfined exec no attachment");
656 return aa_get_newest_label(&profile->label);
657 }
658
659 /* find exec permissions for name */
660 state = aa_str_perms(profile->file.dfa, state, name, cond, &perms);
661 if (perms.allow & MAY_EXEC) {
662 /* exec permission determine how to transition */
663 new = x_to_label(profile, bprm, name, perms.xindex, &target,
664 &info);
665 if (new && new->proxy == profile->label.proxy && info) {
666 /* hack ix fallback - improve how this is detected */
667 goto audit;
668 } else if (!new) {
669 error = -EACCES;
670 info = "profile transition not found";
671 /* remove MAY_EXEC to audit as failure */
672 perms.allow &= ~MAY_EXEC;
673 } else {
674 /* verify that each component's xattr requirements are
675 * met, and fail execution otherwise
676 */
677 label_for_each(i, new, component) {
678 if (aa_xattrs_match(bprm, component, state) <
679 0) {
680 error = -EACCES;
681 info = "required xattrs not present";
682 perms.allow &= ~MAY_EXEC;
683 aa_put_label(new);
684 new = NULL;
685 goto audit;
686 }
687 }
688 }
689 } else if (COMPLAIN_MODE(profile)) {
690 /* no exec permission - learning mode */
691 struct aa_profile *new_profile = NULL;
692 char *n = kstrdup(name, GFP_ATOMIC);
693
694 if (n) {
695 /* name is ptr into buffer */
696 long pos = name - buffer;
697 /* break per cpu buffer hold */
698 put_buffers(buffer);
699 new_profile = aa_new_null_profile(profile, false, n,
700 GFP_KERNEL);
701 get_buffers(buffer);
702 name = buffer + pos;
703 strcpy((char *)name, n);
704 kfree(n);
705 }
706 if (!new_profile) {
707 error = -ENOMEM;
708 info = "could not create null profile";
709 } else {
710 error = -EACCES;
711 new = &new_profile->label;
712 }
713 perms.xindex |= AA_X_UNSAFE;
714 } else
715 /* fail exec */
716 error = -EACCES;
717
718 if (!new)
719 goto audit;
720
721
722 if (!(perms.xindex & AA_X_UNSAFE)) {
723 if (DEBUG_ON) {
724 dbg_printk("apparmor: scrubbing environment variables"
725 " for %s profile=", name);
726 aa_label_printk(new, GFP_ATOMIC);
727 dbg_printk("\n");
728 }
729 *secure_exec = true;
730 }
731
732audit:
733 aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, target, new,
734 cond->uid, info, error);
735 if (!new || nonewprivs) {
736 aa_put_label(new);
737 return ERR_PTR(error);
738 }
739
740 return new;
741}
742
743static int profile_onexec(struct aa_profile *profile, struct aa_label *onexec,
744 bool stack, const struct linux_binprm *bprm,
745 char *buffer, struct path_cond *cond,
746 bool *secure_exec)
747{
748 unsigned int state = profile->file.start;
749 struct aa_perms perms = {};
750 const char *xname = NULL, *info = "change_profile onexec";
751 int error = -EACCES;
752
753 AA_BUG(!profile);
754 AA_BUG(!onexec);
755 AA_BUG(!bprm);
756 AA_BUG(!buffer);
757
758 if (profile_unconfined(profile)) {
759 /* change_profile on exec already granted */
760 /*
761 * NOTE: Domain transitions from unconfined are allowed
762 * even when no_new_privs is set because this aways results
763 * in a further reduction of permissions.
764 */
765 return 0;
766 }
767
768 error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer,
769 &xname, &info, profile->disconnected);
770 if (error) {
771 if (profile_unconfined(profile) ||
772 (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) {
773 AA_DEBUG("name lookup ix on error");
774 error = 0;
775 }
776 xname = bprm->filename;
777 goto audit;
778 }
779
780 /* find exec permissions for name */
781 state = aa_str_perms(profile->file.dfa, state, xname, cond, &perms);
782 if (!(perms.allow & AA_MAY_ONEXEC)) {
783 info = "no change_onexec valid for executable";
784 goto audit;
785 }
786 /* test if this exec can be paired with change_profile onexec.
787 * onexec permission is linked to exec with a standard pairing
788 * exec\0change_profile
789 */
790 state = aa_dfa_null_transition(profile->file.dfa, state);
791 error = change_profile_perms(profile, onexec, stack, AA_MAY_ONEXEC,
792 state, &perms);
793 if (error) {
794 perms.allow &= ~AA_MAY_ONEXEC;
795 goto audit;
796 }
797
798 if (!(perms.xindex & AA_X_UNSAFE)) {
799 if (DEBUG_ON) {
800 dbg_printk("apparmor: scrubbing environment "
801 "variables for %s label=", xname);
802 aa_label_printk(onexec, GFP_ATOMIC);
803 dbg_printk("\n");
804 }
805 *secure_exec = true;
806 }
807
808audit:
809 return aa_audit_file(profile, &perms, OP_EXEC, AA_MAY_ONEXEC, xname,
810 NULL, onexec, cond->uid, info, error);
811}
812
813/* ensure none ns domain transitions are correctly applied with onexec */
814
815static struct aa_label *handle_onexec(struct aa_label *label,
816 struct aa_label *onexec, bool stack,
817 const struct linux_binprm *bprm,
818 char *buffer, struct path_cond *cond,
819 bool *unsafe)
820{
821 struct aa_profile *profile;
822 struct aa_label *new;
823 int error;
824
825 AA_BUG(!label);
826 AA_BUG(!onexec);
827 AA_BUG(!bprm);
828 AA_BUG(!buffer);
829
830 if (!stack) {
831 error = fn_for_each_in_ns(label, profile,
832 profile_onexec(profile, onexec, stack,
833 bprm, buffer, cond, unsafe));
834 if (error)
835 return ERR_PTR(error);
836 new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
837 aa_get_newest_label(onexec),
838 profile_transition(profile, bprm, buffer,
839 cond, unsafe));
840
841 } else {
842 /* TODO: determine how much we want to losen this */
843 error = fn_for_each_in_ns(label, profile,
844 profile_onexec(profile, onexec, stack, bprm,
845 buffer, cond, unsafe));
846 if (error)
847 return ERR_PTR(error);
848 new = fn_label_build_in_ns(label, profile, GFP_ATOMIC,
849 aa_label_merge(&profile->label, onexec,
850 GFP_ATOMIC),
851 profile_transition(profile, bprm, buffer,
852 cond, unsafe));
853 }
854
855 if (new)
856 return new;
857
858 /* TODO: get rid of GLOBAL_ROOT_UID */
859 error = fn_for_each_in_ns(label, profile,
860 aa_audit_file(profile, &nullperms, OP_CHANGE_ONEXEC,
861 AA_MAY_ONEXEC, bprm->filename, NULL,
862 onexec, GLOBAL_ROOT_UID,
863 "failed to build target label", -ENOMEM));
864 return ERR_PTR(error);
865}
866
867/**
868 * apparmor_bprm_set_creds - set the new creds on the bprm struct
869 * @bprm: binprm for the exec (NOT NULL)
870 *
871 * Returns: %0 or error on failure
872 *
873 * TODO: once the other paths are done see if we can't refactor into a fn
874 */
875int apparmor_bprm_set_creds(struct linux_binprm *bprm)
876{
877 struct aa_task_ctx *ctx;
878 struct aa_label *label, *new = NULL;
879 struct aa_profile *profile;
880 char *buffer = NULL;
881 const char *info = NULL;
882 int error = 0;
883 bool unsafe = false;
884 struct path_cond cond = {
885 file_inode(bprm->file)->i_uid,
886 file_inode(bprm->file)->i_mode
887 };
888
889 if (bprm->called_set_creds)
890 return 0;
891
892 ctx = task_ctx(current);
893 AA_BUG(!cred_label(bprm->cred));
894 AA_BUG(!ctx);
895
896 label = aa_get_newest_label(cred_label(bprm->cred));
897
898 /*
899 * Detect no new privs being set, and store the label it
900 * occurred under. Ideally this would happen when nnp
901 * is set but there isn't a good way to do that yet.
902 *
903 * Testing for unconfined must be done before the subset test
904 */
905 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
906 !ctx->nnp)
907 ctx->nnp = aa_get_label(label);
908
909 /* buffer freed below, name is pointer into buffer */
910 get_buffers(buffer);
911 /* Test for onexec first as onexec override other x transitions. */
912 if (ctx->onexec)
913 new = handle_onexec(label, ctx->onexec, ctx->token,
914 bprm, buffer, &cond, &unsafe);
915 else
916 new = fn_label_build(label, profile, GFP_ATOMIC,
917 profile_transition(profile, bprm, buffer,
918 &cond, &unsafe));
919
920 AA_BUG(!new);
921 if (IS_ERR(new)) {
922 error = PTR_ERR(new);
923 goto done;
924 } else if (!new) {
925 error = -ENOMEM;
926 goto done;
927 }
928
929 /* Policy has specified a domain transitions. If no_new_privs and
930 * confined ensure the transition is to confinement that is subset
931 * of the confinement when the task entered no new privs.
932 *
933 * NOTE: Domain transitions from unconfined and to stacked
934 * subsets are allowed even when no_new_privs is set because this
935 * aways results in a further reduction of permissions.
936 */
937 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
938 !unconfined(label) && !aa_label_is_subset(new, ctx->nnp)) {
939 error = -EPERM;
940 info = "no new privs";
941 goto audit;
942 }
943
944 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
945 /* FIXME: currently don't mediate shared state */
946 ;
947 }
948
949 if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
950 /* TODO: test needs to be profile of label to new */
951 error = may_change_ptraced_domain(new, &info);
952 if (error)
953 goto audit;
954 }
955
956 if (unsafe) {
957 if (DEBUG_ON) {
958 dbg_printk("scrubbing environment variables for %s "
959 "label=", bprm->filename);
960 aa_label_printk(new, GFP_ATOMIC);
961 dbg_printk("\n");
962 }
963 bprm->secureexec = 1;
964 }
965
966 if (label->proxy != new->proxy) {
967 /* when transitioning clear unsafe personality bits */
968 if (DEBUG_ON) {
969 dbg_printk("apparmor: clearing unsafe personality "
970 "bits. %s label=", bprm->filename);
971 aa_label_printk(new, GFP_ATOMIC);
972 dbg_printk("\n");
973 }
974 bprm->per_clear |= PER_CLEAR_ON_SETID;
975 }
976 aa_put_label(cred_label(bprm->cred));
977 /* transfer reference, released when cred is freed */
978 cred_label(bprm->cred) = new;
979
980done:
981 aa_put_label(label);
982 put_buffers(buffer);
983
984 return error;
985
986audit:
987 error = fn_for_each(label, profile,
988 aa_audit_file(profile, &nullperms, OP_EXEC, MAY_EXEC,
989 bprm->filename, NULL, new,
990 file_inode(bprm->file)->i_uid, info,
991 error));
992 aa_put_label(new);
993 goto done;
994}
995
996/*
997 * Functions for self directed profile change
998 */
999
1000
1001/* helper fn for change_hat
1002 *
1003 * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL
1004 */
1005static struct aa_label *build_change_hat(struct aa_profile *profile,
1006 const char *name, bool sibling)
1007{
1008 struct aa_profile *root, *hat = NULL;
1009 const char *info = NULL;
1010 int error = 0;
1011
1012 if (sibling && PROFILE_IS_HAT(profile)) {
1013 root = aa_get_profile_rcu(&profile->parent);
1014 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1015 root = aa_get_profile(profile);
1016 } else {
1017 info = "conflicting target types";
1018 error = -EPERM;
1019 goto audit;
1020 }
1021
1022 hat = aa_find_child(root, name);
1023 if (!hat) {
1024 error = -ENOENT;
1025 if (COMPLAIN_MODE(profile)) {
1026 hat = aa_new_null_profile(profile, true, name,
1027 GFP_KERNEL);
1028 if (!hat) {
1029 info = "failed null profile create";
1030 error = -ENOMEM;
1031 }
1032 }
1033 }
1034 aa_put_profile(root);
1035
1036audit:
1037 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT, AA_MAY_CHANGEHAT,
1038 name, hat ? hat->base.hname : NULL,
1039 hat ? &hat->label : NULL, GLOBAL_ROOT_UID, NULL,
1040 error);
1041 if (!hat || (error && error != -ENOENT))
1042 return ERR_PTR(error);
1043 /* if hat && error - complain mode, already audited and we adjust for
1044 * complain mode allow by returning hat->label
1045 */
1046 return &hat->label;
1047}
1048
1049/* helper fn for changing into a hat
1050 *
1051 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1052 */
1053static struct aa_label *change_hat(struct aa_label *label, const char *hats[],
1054 int count, int flags)
1055{
1056 struct aa_profile *profile, *root, *hat = NULL;
1057 struct aa_label *new;
1058 struct label_it it;
1059 bool sibling = false;
1060 const char *name, *info = NULL;
1061 int i, error;
1062
1063 AA_BUG(!label);
1064 AA_BUG(!hats);
1065 AA_BUG(count < 1);
1066
1067 if (PROFILE_IS_HAT(labels_profile(label)))
1068 sibling = true;
1069
1070 /*find first matching hat */
1071 for (i = 0; i < count && !hat; i++) {
1072 name = hats[i];
1073 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1074 if (sibling && PROFILE_IS_HAT(profile)) {
1075 root = aa_get_profile_rcu(&profile->parent);
1076 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1077 root = aa_get_profile(profile);
1078 } else { /* conflicting change type */
1079 info = "conflicting targets types";
1080 error = -EPERM;
1081 goto fail;
1082 }
1083 hat = aa_find_child(root, name);
1084 aa_put_profile(root);
1085 if (!hat) {
1086 if (!COMPLAIN_MODE(profile))
1087 goto outer_continue;
1088 /* complain mode succeed as if hat */
1089 } else if (!PROFILE_IS_HAT(hat)) {
1090 info = "target not hat";
1091 error = -EPERM;
1092 aa_put_profile(hat);
1093 goto fail;
1094 }
1095 aa_put_profile(hat);
1096 }
1097 /* found a hat for all profiles in ns */
1098 goto build;
1099outer_continue:
1100 ;
1101 }
1102 /* no hats that match, find appropriate error
1103 *
1104 * In complain mode audit of the failure is based off of the first
1105 * hat supplied. This is done due how userspace interacts with
1106 * change_hat.
1107 */
1108 name = NULL;
1109 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1110 if (!list_empty(&profile->base.profiles)) {
1111 info = "hat not found";
1112 error = -ENOENT;
1113 goto fail;
1114 }
1115 }
1116 info = "no hats defined";
1117 error = -ECHILD;
1118
1119fail:
1120 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1121 /*
1122 * no target as it has failed to be found or built
1123 *
1124 * change_hat uses probing and should not log failures
1125 * related to missing hats
1126 */
1127 /* TODO: get rid of GLOBAL_ROOT_UID */
1128 if (count > 1 || COMPLAIN_MODE(profile)) {
1129 aa_audit_file(profile, &nullperms, OP_CHANGE_HAT,
1130 AA_MAY_CHANGEHAT, name, NULL, NULL,
1131 GLOBAL_ROOT_UID, info, error);
1132 }
1133 }
1134 return ERR_PTR(error);
1135
1136build:
1137 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1138 build_change_hat(profile, name, sibling),
1139 aa_get_label(&profile->label));
1140 if (!new) {
1141 info = "label build failed";
1142 error = -ENOMEM;
1143 goto fail;
1144 } /* else if (IS_ERR) build_change_hat has logged error so return new */
1145
1146 return new;
1147}
1148
1149/**
1150 * aa_change_hat - change hat to/from subprofile
1151 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1152 * @count: number of hat names in @hats
1153 * @token: magic value to validate the hat change
1154 * @flags: flags affecting behavior of the change
1155 *
1156 * Returns %0 on success, error otherwise.
1157 *
1158 * Change to the first profile specified in @hats that exists, and store
1159 * the @hat_magic in the current task context. If the count == 0 and the
1160 * @token matches that stored in the current task context, return to the
1161 * top level profile.
1162 *
1163 * change_hat only applies to profiles in the current ns, and each profile
1164 * in the ns must make the same transition otherwise change_hat will fail.
1165 */
1166int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1167{
1168 const struct cred *cred;
1169 struct aa_task_ctx *ctx = task_ctx(current);
1170 struct aa_label *label, *previous, *new = NULL, *target = NULL;
1171 struct aa_profile *profile;
1172 struct aa_perms perms = {};
1173 const char *info = NULL;
1174 int error = 0;
1175
1176 /* released below */
1177 cred = get_current_cred();
1178 label = aa_get_newest_cred_label(cred);
1179 previous = aa_get_newest_label(ctx->previous);
1180
1181 /*
1182 * Detect no new privs being set, and store the label it
1183 * occurred under. Ideally this would happen when nnp
1184 * is set but there isn't a good way to do that yet.
1185 *
1186 * Testing for unconfined must be done before the subset test
1187 */
1188 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1189 ctx->nnp = aa_get_label(label);
1190
1191 if (unconfined(label)) {
1192 info = "unconfined can not change_hat";
1193 error = -EPERM;
1194 goto fail;
1195 }
1196
1197 if (count) {
1198 new = change_hat(label, hats, count, flags);
1199 AA_BUG(!new);
1200 if (IS_ERR(new)) {
1201 error = PTR_ERR(new);
1202 new = NULL;
1203 /* already audited */
1204 goto out;
1205 }
1206
1207 error = may_change_ptraced_domain(new, &info);
1208 if (error)
1209 goto fail;
1210
1211 /*
1212 * no new privs prevents domain transitions that would
1213 * reduce restrictions.
1214 */
1215 if (task_no_new_privs(current) && !unconfined(label) &&
1216 !aa_label_is_subset(new, ctx->nnp)) {
1217 /* not an apparmor denial per se, so don't log it */
1218 AA_DEBUG("no_new_privs - change_hat denied");
1219 error = -EPERM;
1220 goto out;
1221 }
1222
1223 if (flags & AA_CHANGE_TEST)
1224 goto out;
1225
1226 target = new;
1227 error = aa_set_current_hat(new, token);
1228 if (error == -EACCES)
1229 /* kill task in case of brute force attacks */
1230 goto kill;
1231 } else if (previous && !(flags & AA_CHANGE_TEST)) {
1232 /*
1233 * no new privs prevents domain transitions that would
1234 * reduce restrictions.
1235 */
1236 if (task_no_new_privs(current) && !unconfined(label) &&
1237 !aa_label_is_subset(previous, ctx->nnp)) {
1238 /* not an apparmor denial per se, so don't log it */
1239 AA_DEBUG("no_new_privs - change_hat denied");
1240 error = -EPERM;
1241 goto out;
1242 }
1243
1244 /* Return to saved label. Kill task if restore fails
1245 * to avoid brute force attacks
1246 */
1247 target = previous;
1248 error = aa_restore_previous_label(token);
1249 if (error) {
1250 if (error == -EACCES)
1251 goto kill;
1252 goto fail;
1253 }
1254 } /* else ignore @flags && restores when there is no saved profile */
1255
1256out:
1257 aa_put_label(new);
1258 aa_put_label(previous);
1259 aa_put_label(label);
1260 put_cred(cred);
1261
1262 return error;
1263
1264kill:
1265 info = "failed token match";
1266 perms.kill = AA_MAY_CHANGEHAT;
1267
1268fail:
1269 fn_for_each_in_ns(label, profile,
1270 aa_audit_file(profile, &perms, OP_CHANGE_HAT,
1271 AA_MAY_CHANGEHAT, NULL, NULL, target,
1272 GLOBAL_ROOT_UID, info, error));
1273
1274 goto out;
1275}
1276
1277
1278static int change_profile_perms_wrapper(const char *op, const char *name,
1279 struct aa_profile *profile,
1280 struct aa_label *target, bool stack,
1281 u32 request, struct aa_perms *perms)
1282{
1283 const char *info = NULL;
1284 int error = 0;
1285
1286 if (!error)
1287 error = change_profile_perms(profile, target, stack, request,
1288 profile->file.start, perms);
1289 if (error)
1290 error = aa_audit_file(profile, perms, op, request, name,
1291 NULL, target, GLOBAL_ROOT_UID, info,
1292 error);
1293
1294 return error;
1295}
1296
1297/**
1298 * aa_change_profile - perform a one-way profile transition
1299 * @fqname: name of profile may include namespace (NOT NULL)
1300 * @onexec: whether this transition is to take place immediately or at exec
1301 * @flags: flags affecting change behavior
1302 *
1303 * Change to new profile @name. Unlike with hats, there is no way
1304 * to change back. If @name isn't specified the current profile name is
1305 * used.
1306 * If @onexec then the transition is delayed until
1307 * the next exec.
1308 *
1309 * Returns %0 on success, error otherwise.
1310 */
1311int aa_change_profile(const char *fqname, int flags)
1312{
1313 struct aa_label *label, *new = NULL, *target = NULL;
1314 struct aa_profile *profile;
1315 struct aa_perms perms = {};
1316 const char *info = NULL;
1317 const char *auditname = fqname; /* retain leading & if stack */
1318 bool stack = flags & AA_CHANGE_STACK;
1319 struct aa_task_ctx *ctx = task_ctx(current);
1320 int error = 0;
1321 char *op;
1322 u32 request;
1323
1324 label = aa_get_current_label();
1325
1326 /*
1327 * Detect no new privs being set, and store the label it
1328 * occurred under. Ideally this would happen when nnp
1329 * is set but there isn't a good way to do that yet.
1330 *
1331 * Testing for unconfined must be done before the subset test
1332 */
1333 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1334 ctx->nnp = aa_get_label(label);
1335
1336 if (!fqname || !*fqname) {
1337 AA_DEBUG("no profile name");
1338 return -EINVAL;
1339 }
1340
1341 if (flags & AA_CHANGE_ONEXEC) {
1342 request = AA_MAY_ONEXEC;
1343 if (stack)
1344 op = OP_STACK_ONEXEC;
1345 else
1346 op = OP_CHANGE_ONEXEC;
1347 } else {
1348 request = AA_MAY_CHANGE_PROFILE;
1349 if (stack)
1350 op = OP_STACK;
1351 else
1352 op = OP_CHANGE_PROFILE;
1353 }
1354
1355 label = aa_get_current_label();
1356
1357 if (*fqname == '&') {
1358 stack = true;
1359 /* don't have label_parse() do stacking */
1360 fqname++;
1361 }
1362 target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1363 if (IS_ERR(target)) {
1364 struct aa_profile *tprofile;
1365
1366 info = "label not found";
1367 error = PTR_ERR(target);
1368 target = NULL;
1369 /*
1370 * TODO: fixme using labels_profile is not right - do profile
1371 * per complain profile
1372 */
1373 if ((flags & AA_CHANGE_TEST) ||
1374 !COMPLAIN_MODE(labels_profile(label)))
1375 goto audit;
1376 /* released below */
1377 tprofile = aa_new_null_profile(labels_profile(label), false,
1378 fqname, GFP_KERNEL);
1379 if (!tprofile) {
1380 info = "failed null profile create";
1381 error = -ENOMEM;
1382 goto audit;
1383 }
1384 target = &tprofile->label;
1385 goto check;
1386 }
1387
1388 /*
1389 * self directed transitions only apply to current policy ns
1390 * TODO: currently requiring perms for stacking and straight change
1391 * stacking doesn't strictly need this. Determine how much
1392 * we want to loosen this restriction for stacking
1393 *
1394 * if (!stack) {
1395 */
1396 error = fn_for_each_in_ns(label, profile,
1397 change_profile_perms_wrapper(op, auditname,
1398 profile, target, stack,
1399 request, &perms));
1400 if (error)
1401 /* auditing done in change_profile_perms_wrapper */
1402 goto out;
1403
1404 /* } */
1405
1406check:
1407 /* check if tracing task is allowed to trace target domain */
1408 error = may_change_ptraced_domain(target, &info);
1409 if (error && !fn_for_each_in_ns(label, profile,
1410 COMPLAIN_MODE(profile)))
1411 goto audit;
1412
1413 /* TODO: add permission check to allow this
1414 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1415 * info = "not a single threaded task";
1416 * error = -EACCES;
1417 * goto audit;
1418 * }
1419 */
1420 if (flags & AA_CHANGE_TEST)
1421 goto out;
1422
1423 /* stacking is always a subset, so only check the nonstack case */
1424 if (!stack) {
1425 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1426 aa_get_label(target),
1427 aa_get_label(&profile->label));
1428 /*
1429 * no new privs prevents domain transitions that would
1430 * reduce restrictions.
1431 */
1432 if (task_no_new_privs(current) && !unconfined(label) &&
1433 !aa_label_is_subset(new, ctx->nnp)) {
1434 /* not an apparmor denial per se, so don't log it */
1435 AA_DEBUG("no_new_privs - change_hat denied");
1436 error = -EPERM;
1437 goto out;
1438 }
1439 }
1440
1441 if (!(flags & AA_CHANGE_ONEXEC)) {
1442 /* only transition profiles in the current ns */
1443 if (stack)
1444 new = aa_label_merge(label, target, GFP_KERNEL);
1445 if (IS_ERR_OR_NULL(new)) {
1446 info = "failed to build target label";
1447 error = PTR_ERR(new);
1448 new = NULL;
1449 perms.allow = 0;
1450 goto audit;
1451 }
1452 error = aa_replace_current_label(new);
1453 } else {
1454 if (new) {
1455 aa_put_label(new);
1456 new = NULL;
1457 }
1458
1459 /* full transition will be built in exec path */
1460 error = aa_set_current_onexec(target, stack);
1461 }
1462
1463audit:
1464 error = fn_for_each_in_ns(label, profile,
1465 aa_audit_file(profile, &perms, op, request, auditname,
1466 NULL, new ? new : target,
1467 GLOBAL_ROOT_UID, info, error));
1468
1469out:
1470 aa_put_label(new);
1471 aa_put_label(target);
1472 aa_put_label(label);
1473
1474 return error;
1475}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AppArmor security module
4 *
5 * This file contains AppArmor policy attachment and domain transitions
6 *
7 * Copyright (C) 2002-2008 Novell/SUSE
8 * Copyright 2009-2010 Canonical Ltd.
9 */
10
11#include <linux/errno.h>
12#include <linux/fs.h>
13#include <linux/file.h>
14#include <linux/mount.h>
15#include <linux/syscalls.h>
16#include <linux/personality.h>
17#include <linux/xattr.h>
18#include <linux/user_namespace.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 * may_change_ptraced_domain - check if can change profile on ptraced task
33 * @to_cred: cred of task changing domain
34 * @to_label: profile to change to (NOT NULL)
35 * @info: message if there is an error
36 *
37 * Check if current is ptraced and if so if the tracing task is allowed
38 * to trace the new domain
39 *
40 * Returns: %0 or error if change not allowed
41 */
42static int may_change_ptraced_domain(const struct cred *to_cred,
43 struct aa_label *to_label,
44 const char **info)
45{
46 struct task_struct *tracer;
47 struct aa_label *tracerl = NULL;
48 const struct cred *tracer_cred = NULL;
49
50 int error = 0;
51
52 rcu_read_lock();
53 tracer = ptrace_parent(current);
54 if (tracer) {
55 /* released below */
56 tracerl = aa_get_task_label(tracer);
57 tracer_cred = get_task_cred(tracer);
58 }
59 /* not ptraced */
60 if (!tracer || unconfined(tracerl))
61 goto out;
62
63 error = aa_may_ptrace(tracer_cred, tracerl, to_cred, to_label,
64 PTRACE_MODE_ATTACH);
65
66out:
67 rcu_read_unlock();
68 aa_put_label(tracerl);
69 put_cred(tracer_cred);
70
71 if (error)
72 *info = "ptrace prevents transition";
73 return error;
74}
75
76/**** TODO: dedup to aa_label_match - needs perm and dfa, merging
77 * specifically this is an exact copy of aa_label_match except
78 * aa_compute_perms is replaced with aa_compute_fperms
79 * and policy->dfa with file->dfa
80 ****/
81/* match a profile and its associated ns component if needed
82 * Assumes visibility test has already been done.
83 * If a subns profile is not to be matched should be prescreened with
84 * visibility test.
85 */
86static inline aa_state_t match_component(struct aa_profile *profile,
87 struct aa_profile *tp,
88 bool stack, aa_state_t state)
89{
90 struct aa_ruleset *rules = list_first_entry(&profile->rules,
91 typeof(*rules), list);
92 const char *ns_name;
93
94 if (stack)
95 state = aa_dfa_match(rules->file->dfa, state, "&");
96 if (profile->ns == tp->ns)
97 return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
98
99 /* try matching with namespace name and then profile */
100 ns_name = aa_ns_name(profile->ns, tp->ns, true);
101 state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
102 state = aa_dfa_match(rules->file->dfa, state, ns_name);
103 state = aa_dfa_match_len(rules->file->dfa, state, ":", 1);
104 return aa_dfa_match(rules->file->dfa, state, tp->base.hname);
105}
106
107/**
108 * label_compound_match - find perms for full compound label
109 * @profile: profile to find perms for
110 * @label: label to check access permissions for
111 * @stack: whether this is a stacking request
112 * @state: state to start match in
113 * @subns: whether to do permission checks on components in a subns
114 * @request: permissions to request
115 * @perms: perms struct to set
116 *
117 * Returns: 0 on success else ERROR
118 *
119 * For the label A//&B//&C this does the perm match for A//&B//&C
120 * @perms should be preinitialized with allperms OR a previous permission
121 * check to be stacked.
122 */
123static int label_compound_match(struct aa_profile *profile,
124 struct aa_label *label, bool stack,
125 aa_state_t state, bool subns, u32 request,
126 struct aa_perms *perms)
127{
128 struct aa_ruleset *rules = list_first_entry(&profile->rules,
129 typeof(*rules), list);
130 struct aa_profile *tp;
131 struct label_it i;
132 struct path_cond cond = { };
133
134 /* find first subcomponent that is visible */
135 label_for_each(i, label, tp) {
136 if (!aa_ns_visible(profile->ns, tp->ns, subns))
137 continue;
138 state = match_component(profile, tp, stack, state);
139 if (!state)
140 goto fail;
141 goto next;
142 }
143
144 /* no component visible */
145 *perms = allperms;
146 return 0;
147
148next:
149 label_for_each_cont(i, label, tp) {
150 if (!aa_ns_visible(profile->ns, tp->ns, subns))
151 continue;
152 state = aa_dfa_match(rules->file->dfa, state, "//&");
153 state = match_component(profile, tp, false, state);
154 if (!state)
155 goto fail;
156 }
157 *perms = *(aa_lookup_fperms(rules->file, state, &cond));
158 aa_apply_modes_to_perms(profile, perms);
159 if ((perms->allow & request) != request)
160 return -EACCES;
161
162 return 0;
163
164fail:
165 *perms = nullperms;
166 return -EACCES;
167}
168
169/**
170 * label_components_match - find perms for all subcomponents of a label
171 * @profile: profile to find perms for
172 * @label: label to check access permissions for
173 * @stack: whether this is a stacking request
174 * @start: state to start match in
175 * @subns: whether to do permission checks on components in a subns
176 * @request: permissions to request
177 * @perms: an initialized perms struct to add accumulation to
178 *
179 * Returns: 0 on success else ERROR
180 *
181 * For the label A//&B//&C this does the perm match for each of A and B and C
182 * @perms should be preinitialized with allperms OR a previous permission
183 * check to be stacked.
184 */
185static int label_components_match(struct aa_profile *profile,
186 struct aa_label *label, bool stack,
187 aa_state_t start, bool subns, u32 request,
188 struct aa_perms *perms)
189{
190 struct aa_ruleset *rules = list_first_entry(&profile->rules,
191 typeof(*rules), list);
192 struct aa_profile *tp;
193 struct label_it i;
194 struct aa_perms tmp;
195 struct path_cond cond = { };
196 aa_state_t state = 0;
197
198 /* find first subcomponent to test */
199 label_for_each(i, label, tp) {
200 if (!aa_ns_visible(profile->ns, tp->ns, subns))
201 continue;
202 state = match_component(profile, tp, stack, start);
203 if (!state)
204 goto fail;
205 goto next;
206 }
207
208 /* no subcomponents visible - no change in perms */
209 return 0;
210
211next:
212 tmp = *(aa_lookup_fperms(rules->file, state, &cond));
213 aa_apply_modes_to_perms(profile, &tmp);
214 aa_perms_accum(perms, &tmp);
215 label_for_each_cont(i, label, tp) {
216 if (!aa_ns_visible(profile->ns, tp->ns, subns))
217 continue;
218 state = match_component(profile, tp, stack, start);
219 if (!state)
220 goto fail;
221 tmp = *(aa_lookup_fperms(rules->file, state, &cond));
222 aa_apply_modes_to_perms(profile, &tmp);
223 aa_perms_accum(perms, &tmp);
224 }
225
226 if ((perms->allow & request) != request)
227 return -EACCES;
228
229 return 0;
230
231fail:
232 *perms = nullperms;
233 return -EACCES;
234}
235
236/**
237 * label_match - do a multi-component label match
238 * @profile: profile to match against (NOT NULL)
239 * @label: label to match (NOT NULL)
240 * @stack: whether this is a stacking request
241 * @state: state to start in
242 * @subns: whether to match subns components
243 * @request: permission request
244 * @perms: Returns computed perms (NOT NULL)
245 *
246 * Returns: the state the match finished in, may be the none matching state
247 */
248static int label_match(struct aa_profile *profile, struct aa_label *label,
249 bool stack, aa_state_t state, bool subns, u32 request,
250 struct aa_perms *perms)
251{
252 int error;
253
254 *perms = nullperms;
255 error = label_compound_match(profile, label, stack, state, subns,
256 request, perms);
257 if (!error)
258 return error;
259
260 *perms = allperms;
261 return label_components_match(profile, label, stack, state, subns,
262 request, perms);
263}
264
265/******* end TODO: dedup *****/
266
267/**
268 * change_profile_perms - find permissions for change_profile
269 * @profile: the current profile (NOT NULL)
270 * @target: label to transition to (NOT NULL)
271 * @stack: whether this is a stacking request
272 * @request: requested perms
273 * @start: state to start matching in
274 * @perms: Returns computed perms (NOT NULL)
275 *
276 *
277 * Returns: permission set
278 *
279 * currently only matches full label A//&B//&C or individual components A, B, C
280 * not arbitrary combinations. Eg. A//&B, C
281 */
282static int change_profile_perms(struct aa_profile *profile,
283 struct aa_label *target, bool stack,
284 u32 request, aa_state_t start,
285 struct aa_perms *perms)
286{
287 if (profile_unconfined(profile)) {
288 perms->allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC;
289 perms->audit = perms->quiet = perms->kill = 0;
290 return 0;
291 }
292
293 /* TODO: add profile in ns screening */
294 return label_match(profile, target, stack, start, true, request, perms);
295}
296
297/**
298 * aa_xattrs_match - check whether a file matches the xattrs defined in profile
299 * @bprm: binprm struct for the process to validate
300 * @profile: profile to match against (NOT NULL)
301 * @state: state to start match in
302 *
303 * Returns: number of extended attributes that matched, or < 0 on error
304 */
305static int aa_xattrs_match(const struct linux_binprm *bprm,
306 struct aa_profile *profile, aa_state_t state)
307{
308 int i;
309 struct dentry *d;
310 char *value = NULL;
311 struct aa_attachment *attach = &profile->attach;
312 int size, value_size = 0, ret = attach->xattr_count;
313
314 if (!bprm || !attach->xattr_count)
315 return 0;
316 might_sleep();
317
318 /* transition from exec match to xattr set */
319 state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
320 d = bprm->file->f_path.dentry;
321
322 for (i = 0; i < attach->xattr_count; i++) {
323 size = vfs_getxattr_alloc(&nop_mnt_idmap, d, attach->xattrs[i],
324 &value, value_size, GFP_KERNEL);
325 if (size >= 0) {
326 u32 index, perm;
327
328 /*
329 * Check the xattr presence before value. This ensure
330 * that not present xattr can be distinguished from a 0
331 * length value or rule that matches any value
332 */
333 state = aa_dfa_null_transition(attach->xmatch->dfa,
334 state);
335 /* Check xattr value */
336 state = aa_dfa_match_len(attach->xmatch->dfa, state,
337 value, size);
338 index = ACCEPT_TABLE(attach->xmatch->dfa)[state];
339 perm = attach->xmatch->perms[index].allow;
340 if (!(perm & MAY_EXEC)) {
341 ret = -EINVAL;
342 goto out;
343 }
344 }
345 /* transition to next element */
346 state = aa_dfa_outofband_transition(attach->xmatch->dfa, state);
347 if (size < 0) {
348 /*
349 * No xattr match, so verify if transition to
350 * next element was valid. IFF so the xattr
351 * was optional.
352 */
353 if (!state) {
354 ret = -EINVAL;
355 goto out;
356 }
357 /* don't count missing optional xattr as matched */
358 ret--;
359 }
360 }
361
362out:
363 kfree(value);
364 return ret;
365}
366
367/**
368 * find_attach - do attachment search for unconfined processes
369 * @bprm: binprm structure of transitioning task
370 * @ns: the current namespace (NOT NULL)
371 * @head: profile list to walk (NOT NULL)
372 * @name: to match against (NOT NULL)
373 * @info: info message if there was an error (NOT NULL)
374 *
375 * Do a linear search on the profiles in the list. There is a matching
376 * preference where an exact match is preferred over a name which uses
377 * expressions to match, and matching expressions with the greatest
378 * xmatch_len are preferred.
379 *
380 * Requires: @head not be shared or have appropriate locks held
381 *
382 * Returns: label or NULL if no match found
383 */
384static struct aa_label *find_attach(const struct linux_binprm *bprm,
385 struct aa_ns *ns, struct list_head *head,
386 const char *name, const char **info)
387{
388 int candidate_len = 0, candidate_xattrs = 0;
389 bool conflict = false;
390 struct aa_profile *profile, *candidate = NULL;
391
392 AA_BUG(!name);
393 AA_BUG(!head);
394
395 rcu_read_lock();
396restart:
397 list_for_each_entry_rcu(profile, head, base.list) {
398 struct aa_attachment *attach = &profile->attach;
399
400 if (profile->label.flags & FLAG_NULL &&
401 &profile->label == ns_unconfined(profile->ns))
402 continue;
403
404 /* Find the "best" matching profile. Profiles must
405 * match the path and extended attributes (if any)
406 * associated with the file. A more specific path
407 * match will be preferred over a less specific one,
408 * and a match with more matching extended attributes
409 * will be preferred over one with fewer. If the best
410 * match has both the same level of path specificity
411 * and the same number of matching extended attributes
412 * as another profile, signal a conflict and refuse to
413 * match.
414 */
415 if (attach->xmatch->dfa) {
416 unsigned int count;
417 aa_state_t state;
418 u32 index, perm;
419
420 state = aa_dfa_leftmatch(attach->xmatch->dfa,
421 attach->xmatch->start[AA_CLASS_XMATCH],
422 name, &count);
423 index = ACCEPT_TABLE(attach->xmatch->dfa)[state];
424 perm = attach->xmatch->perms[index].allow;
425 /* any accepting state means a valid match. */
426 if (perm & MAY_EXEC) {
427 int ret = 0;
428
429 if (count < candidate_len)
430 continue;
431
432 if (bprm && attach->xattr_count) {
433 long rev = READ_ONCE(ns->revision);
434
435 if (!aa_get_profile_not0(profile))
436 goto restart;
437 rcu_read_unlock();
438 ret = aa_xattrs_match(bprm, profile,
439 state);
440 rcu_read_lock();
441 aa_put_profile(profile);
442 if (rev !=
443 READ_ONCE(ns->revision))
444 /* policy changed */
445 goto restart;
446 /*
447 * Fail matching if the xattrs don't
448 * match
449 */
450 if (ret < 0)
451 continue;
452 }
453 /*
454 * TODO: allow for more flexible best match
455 *
456 * The new match isn't more specific
457 * than the current best match
458 */
459 if (count == candidate_len &&
460 ret <= candidate_xattrs) {
461 /* Match is equivalent, so conflict */
462 if (ret == candidate_xattrs)
463 conflict = true;
464 continue;
465 }
466
467 /* Either the same length with more matching
468 * xattrs, or a longer match
469 */
470 candidate = profile;
471 candidate_len = max(count, attach->xmatch_len);
472 candidate_xattrs = ret;
473 conflict = false;
474 }
475 } else if (!strcmp(profile->base.name, name)) {
476 /*
477 * old exact non-re match, without conditionals such
478 * as xattrs. no more searching required
479 */
480 candidate = profile;
481 goto out;
482 }
483 }
484
485 if (!candidate || conflict) {
486 if (conflict)
487 *info = "conflicting profile attachments";
488 rcu_read_unlock();
489 return NULL;
490 }
491
492out:
493 candidate = aa_get_newest_profile(candidate);
494 rcu_read_unlock();
495
496 return &candidate->label;
497}
498
499static const char *next_name(int xtype, const char *name)
500{
501 return NULL;
502}
503
504/**
505 * x_table_lookup - lookup an x transition name via transition table
506 * @profile: current profile (NOT NULL)
507 * @xindex: index into x transition table
508 * @name: returns: name tested to find label (NOT NULL)
509 *
510 * Returns: refcounted label, or NULL on failure (MAYBE NULL)
511 */
512struct aa_label *x_table_lookup(struct aa_profile *profile, u32 xindex,
513 const char **name)
514{
515 struct aa_ruleset *rules = list_first_entry(&profile->rules,
516 typeof(*rules), list);
517 struct aa_label *label = NULL;
518 u32 xtype = xindex & AA_X_TYPE_MASK;
519 int index = xindex & AA_X_INDEX_MASK;
520
521 AA_BUG(!name);
522
523 /* index is guaranteed to be in range, validated at load time */
524 /* TODO: move lookup parsing to unpack time so this is a straight
525 * index into the resultant label
526 */
527 for (*name = rules->file->trans.table[index]; !label && *name;
528 *name = next_name(xtype, *name)) {
529 if (xindex & AA_X_CHILD) {
530 struct aa_profile *new_profile;
531 /* release by caller */
532 new_profile = aa_find_child(profile, *name);
533 if (new_profile)
534 label = &new_profile->label;
535 continue;
536 }
537 label = aa_label_parse(&profile->label, *name, GFP_KERNEL,
538 true, false);
539 if (IS_ERR(label))
540 label = NULL;
541 }
542
543 /* released by caller */
544
545 return label;
546}
547
548/**
549 * x_to_label - get target label for a given xindex
550 * @profile: current profile (NOT NULL)
551 * @bprm: binprm structure of transitioning task
552 * @name: name to lookup (NOT NULL)
553 * @xindex: index into x transition table
554 * @lookupname: returns: name used in lookup if one was specified (NOT NULL)
555 * @info: info message if there was an error (NOT NULL)
556 *
557 * find label for a transition index
558 *
559 * Returns: refcounted label or NULL if not found available
560 */
561static struct aa_label *x_to_label(struct aa_profile *profile,
562 const struct linux_binprm *bprm,
563 const char *name, u32 xindex,
564 const char **lookupname,
565 const char **info)
566{
567 struct aa_ruleset *rules = list_first_entry(&profile->rules,
568 typeof(*rules), list);
569 struct aa_label *new = NULL;
570 struct aa_ns *ns = profile->ns;
571 u32 xtype = xindex & AA_X_TYPE_MASK;
572 const char *stack = NULL;
573
574 switch (xtype) {
575 case AA_X_NONE:
576 /* fail exec unless ix || ux fallback - handled by caller */
577 *lookupname = NULL;
578 break;
579 case AA_X_TABLE:
580 /* TODO: fix when perm mapping done at unload */
581 stack = rules->file->trans.table[xindex & AA_X_INDEX_MASK];
582 if (*stack != '&') {
583 /* released by caller */
584 new = x_table_lookup(profile, xindex, lookupname);
585 stack = NULL;
586 break;
587 }
588 fallthrough; /* to X_NAME */
589 case AA_X_NAME:
590 if (xindex & AA_X_CHILD)
591 /* released by caller */
592 new = find_attach(bprm, ns, &profile->base.profiles,
593 name, info);
594 else
595 /* released by caller */
596 new = find_attach(bprm, ns, &ns->base.profiles,
597 name, info);
598 *lookupname = name;
599 break;
600 }
601
602 if (!new) {
603 if (xindex & AA_X_INHERIT) {
604 /* (p|c|n)ix - don't change profile but do
605 * use the newest version
606 */
607 *info = "ix fallback";
608 /* no profile && no error */
609 new = aa_get_newest_label(&profile->label);
610 } else if (xindex & AA_X_UNCONFINED) {
611 new = aa_get_newest_label(ns_unconfined(profile->ns));
612 *info = "ux fallback";
613 }
614 }
615
616 if (new && stack) {
617 /* base the stack on post domain transition */
618 struct aa_label *base = new;
619
620 new = aa_label_parse(base, stack, GFP_KERNEL, true, false);
621 if (IS_ERR(new))
622 new = NULL;
623 aa_put_label(base);
624 }
625
626 /* released by caller */
627 return new;
628}
629
630static struct aa_label *profile_transition(const struct cred *subj_cred,
631 struct aa_profile *profile,
632 const struct linux_binprm *bprm,
633 char *buffer, struct path_cond *cond,
634 bool *secure_exec)
635{
636 struct aa_ruleset *rules = list_first_entry(&profile->rules,
637 typeof(*rules), list);
638 struct aa_label *new = NULL;
639 struct aa_profile *new_profile = 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 info = "profile transition not found";
685 /* remove MAY_EXEC to audit as failure or complaint */
686 perms.allow &= ~MAY_EXEC;
687 if (COMPLAIN_MODE(profile)) {
688 /* create null profile instead of failing */
689 goto create_learning_profile;
690 }
691 error = -EACCES;
692 }
693 } else if (COMPLAIN_MODE(profile)) {
694create_learning_profile:
695 /* no exec permission - learning mode */
696 new_profile = aa_new_learning_profile(profile, false, name,
697 GFP_KERNEL);
698 if (!new_profile) {
699 error = -ENOMEM;
700 info = "could not create null profile";
701 } else {
702 error = -EACCES;
703 new = &new_profile->label;
704 }
705 perms.xindex |= AA_X_UNSAFE;
706 } else
707 /* fail exec */
708 error = -EACCES;
709
710 if (!new)
711 goto audit;
712
713
714 if (!(perms.xindex & AA_X_UNSAFE)) {
715 if (DEBUG_ON) {
716 dbg_printk("apparmor: setting AT_SECURE for %s profile=",
717 name);
718 aa_label_printk(new, GFP_KERNEL);
719 dbg_printk("\n");
720 }
721 *secure_exec = true;
722 }
723
724audit:
725 aa_audit_file(subj_cred, profile, &perms, OP_EXEC, MAY_EXEC, name,
726 target, new,
727 cond->uid, info, error);
728 if (!new || nonewprivs) {
729 aa_put_label(new);
730 return ERR_PTR(error);
731 }
732
733 return new;
734}
735
736static int profile_onexec(const struct cred *subj_cred,
737 struct aa_profile *profile, struct aa_label *onexec,
738 bool stack, const struct linux_binprm *bprm,
739 char *buffer, struct path_cond *cond,
740 bool *secure_exec)
741{
742 struct aa_ruleset *rules = list_first_entry(&profile->rules,
743 typeof(*rules), list);
744 aa_state_t state = rules->file->start[AA_CLASS_FILE];
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(rules->file, 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(rules->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: setting AT_SECURE for %s label=",
797 xname);
798 aa_label_printk(onexec, GFP_KERNEL);
799 dbg_printk("\n");
800 }
801 *secure_exec = true;
802 }
803
804audit:
805 return aa_audit_file(subj_cred, profile, &perms, OP_EXEC,
806 AA_MAY_ONEXEC, xname,
807 NULL, onexec, cond->uid, info, error);
808}
809
810/* ensure none ns domain transitions are correctly applied with onexec */
811
812static struct aa_label *handle_onexec(const struct cred *subj_cred,
813 struct aa_label *label,
814 struct aa_label *onexec, bool stack,
815 const struct linux_binprm *bprm,
816 char *buffer, struct path_cond *cond,
817 bool *unsafe)
818{
819 struct aa_profile *profile;
820 struct aa_label *new;
821 int error;
822
823 AA_BUG(!label);
824 AA_BUG(!onexec);
825 AA_BUG(!bprm);
826 AA_BUG(!buffer);
827
828 /* TODO: determine how much we want to loosen this */
829 error = fn_for_each_in_ns(label, profile,
830 profile_onexec(subj_cred, profile, onexec, stack,
831 bprm, buffer, cond, unsafe));
832 if (error)
833 return ERR_PTR(error);
834
835 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
836 stack ? aa_label_merge(&profile->label, onexec,
837 GFP_KERNEL)
838 : aa_get_newest_label(onexec),
839 profile_transition(subj_cred, profile, bprm,
840 buffer, cond, unsafe));
841 if (new)
842 return new;
843
844 /* TODO: get rid of GLOBAL_ROOT_UID */
845 error = fn_for_each_in_ns(label, profile,
846 aa_audit_file(subj_cred, profile, &nullperms,
847 OP_CHANGE_ONEXEC,
848 AA_MAY_ONEXEC, bprm->filename, NULL,
849 onexec, GLOBAL_ROOT_UID,
850 "failed to build target label", -ENOMEM));
851 return ERR_PTR(error);
852}
853
854/**
855 * apparmor_bprm_creds_for_exec - Update the new creds on the bprm struct
856 * @bprm: binprm for the exec (NOT NULL)
857 *
858 * Returns: %0 or error on failure
859 *
860 * TODO: once the other paths are done see if we can't refactor into a fn
861 */
862int apparmor_bprm_creds_for_exec(struct linux_binprm *bprm)
863{
864 struct aa_task_ctx *ctx;
865 struct aa_label *label, *new = NULL;
866 const struct cred *subj_cred;
867 struct aa_profile *profile;
868 char *buffer = NULL;
869 const char *info = NULL;
870 int error = 0;
871 bool unsafe = false;
872 vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(bprm->file),
873 file_inode(bprm->file));
874 struct path_cond cond = {
875 vfsuid_into_kuid(vfsuid),
876 file_inode(bprm->file)->i_mode
877 };
878
879 subj_cred = current_cred();
880 ctx = task_ctx(current);
881 AA_BUG(!cred_label(bprm->cred));
882 AA_BUG(!ctx);
883
884 label = aa_get_newest_label(cred_label(bprm->cred));
885
886 /*
887 * Detect no new privs being set, and store the label it
888 * occurred under. Ideally this would happen when nnp
889 * is set but there isn't a good way to do that yet.
890 *
891 * Testing for unconfined must be done before the subset test
892 */
893 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) && !unconfined(label) &&
894 !ctx->nnp)
895 ctx->nnp = aa_get_label(label);
896
897 /* buffer freed below, name is pointer into buffer */
898 buffer = aa_get_buffer(false);
899 if (!buffer) {
900 error = -ENOMEM;
901 goto done;
902 }
903
904 /* Test for onexec first as onexec override other x transitions. */
905 if (ctx->onexec)
906 new = handle_onexec(subj_cred, label, ctx->onexec, ctx->token,
907 bprm, buffer, &cond, &unsafe);
908 else
909 new = fn_label_build(label, profile, GFP_KERNEL,
910 profile_transition(subj_cred, profile, bprm,
911 buffer,
912 &cond, &unsafe));
913
914 AA_BUG(!new);
915 if (IS_ERR(new)) {
916 error = PTR_ERR(new);
917 goto done;
918 } else if (!new) {
919 error = -ENOMEM;
920 goto done;
921 }
922
923 /* Policy has specified a domain transitions. If no_new_privs and
924 * confined ensure the transition is to confinement that is subset
925 * of the confinement when the task entered no new privs.
926 *
927 * NOTE: Domain transitions from unconfined and to stacked
928 * subsets are allowed even when no_new_privs is set because this
929 * aways results in a further reduction of permissions.
930 */
931 if ((bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) &&
932 !unconfined(label) &&
933 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
934 error = -EPERM;
935 info = "no new privs";
936 goto audit;
937 }
938
939 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
940 /* FIXME: currently don't mediate shared state */
941 ;
942 }
943
944 if (bprm->unsafe & (LSM_UNSAFE_PTRACE)) {
945 /* TODO: test needs to be profile of label to new */
946 error = may_change_ptraced_domain(bprm->cred, new, &info);
947 if (error)
948 goto audit;
949 }
950
951 if (unsafe) {
952 if (DEBUG_ON) {
953 dbg_printk("setting AT_SECURE for %s label=",
954 bprm->filename);
955 aa_label_printk(new, GFP_KERNEL);
956 dbg_printk("\n");
957 }
958 bprm->secureexec = 1;
959 }
960
961 if (label->proxy != new->proxy) {
962 /* when transitioning clear unsafe personality bits */
963 if (DEBUG_ON) {
964 dbg_printk("apparmor: clearing unsafe personality bits. %s label=",
965 bprm->filename);
966 aa_label_printk(new, GFP_KERNEL);
967 dbg_printk("\n");
968 }
969 bprm->per_clear |= PER_CLEAR_ON_SETID;
970 }
971 aa_put_label(cred_label(bprm->cred));
972 /* transfer reference, released when cred is freed */
973 set_cred_label(bprm->cred, new);
974
975done:
976 aa_put_label(label);
977 aa_put_buffer(buffer);
978
979 return error;
980
981audit:
982 error = fn_for_each(label, profile,
983 aa_audit_file(current_cred(), profile, &nullperms,
984 OP_EXEC, MAY_EXEC,
985 bprm->filename, NULL, new,
986 vfsuid_into_kuid(vfsuid), info, error));
987 aa_put_label(new);
988 goto done;
989}
990
991/*
992 * Functions for self directed profile change
993 */
994
995
996/* helper fn for change_hat
997 *
998 * Returns: label for hat transition OR ERR_PTR. Does NOT return NULL
999 */
1000static struct aa_label *build_change_hat(const struct cred *subj_cred,
1001 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_learning_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(subj_cred, profile, &nullperms, OP_CHANGE_HAT,
1034 AA_MAY_CHANGEHAT,
1035 name, hat ? hat->base.hname : NULL,
1036 hat ? &hat->label : NULL, GLOBAL_ROOT_UID, info,
1037 error);
1038 if (!hat || (error && error != -ENOENT))
1039 return ERR_PTR(error);
1040 /* if hat && error - complain mode, already audited and we adjust for
1041 * complain mode allow by returning hat->label
1042 */
1043 return &hat->label;
1044}
1045
1046/* helper fn for changing into a hat
1047 *
1048 * Returns: label for hat transition or ERR_PTR. Does not return NULL
1049 */
1050static struct aa_label *change_hat(const struct cred *subj_cred,
1051 struct aa_label *label, const char *hats[],
1052 int count, int flags)
1053{
1054 struct aa_profile *profile, *root, *hat = NULL;
1055 struct aa_label *new;
1056 struct label_it it;
1057 bool sibling = false;
1058 const char *name, *info = NULL;
1059 int i, error;
1060
1061 AA_BUG(!label);
1062 AA_BUG(!hats);
1063 AA_BUG(count < 1);
1064
1065 if (PROFILE_IS_HAT(labels_profile(label)))
1066 sibling = true;
1067
1068 /*find first matching hat */
1069 for (i = 0; i < count && !hat; i++) {
1070 name = hats[i];
1071 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1072 if (sibling && PROFILE_IS_HAT(profile)) {
1073 root = aa_get_profile_rcu(&profile->parent);
1074 } else if (!sibling && !PROFILE_IS_HAT(profile)) {
1075 root = aa_get_profile(profile);
1076 } else { /* conflicting change type */
1077 info = "conflicting targets types";
1078 error = -EPERM;
1079 goto fail;
1080 }
1081 hat = aa_find_child(root, name);
1082 aa_put_profile(root);
1083 if (!hat) {
1084 if (!COMPLAIN_MODE(profile))
1085 goto outer_continue;
1086 /* complain mode succeed as if hat */
1087 } else if (!PROFILE_IS_HAT(hat)) {
1088 info = "target not hat";
1089 error = -EPERM;
1090 aa_put_profile(hat);
1091 goto fail;
1092 }
1093 aa_put_profile(hat);
1094 }
1095 /* found a hat for all profiles in ns */
1096 goto build;
1097outer_continue:
1098 ;
1099 }
1100 /* no hats that match, find appropriate error
1101 *
1102 * In complain mode audit of the failure is based off of the first
1103 * hat supplied. This is done due how userspace interacts with
1104 * change_hat.
1105 */
1106 name = NULL;
1107 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1108 if (!list_empty(&profile->base.profiles)) {
1109 info = "hat not found";
1110 error = -ENOENT;
1111 goto fail;
1112 }
1113 }
1114 info = "no hats defined";
1115 error = -ECHILD;
1116
1117fail:
1118 label_for_each_in_ns(it, labels_ns(label), label, profile) {
1119 /*
1120 * no target as it has failed to be found or built
1121 *
1122 * change_hat uses probing and should not log failures
1123 * related to missing hats
1124 */
1125 /* TODO: get rid of GLOBAL_ROOT_UID */
1126 if (count > 1 || COMPLAIN_MODE(profile)) {
1127 aa_audit_file(subj_cred, profile, &nullperms,
1128 OP_CHANGE_HAT,
1129 AA_MAY_CHANGEHAT, name, NULL, NULL,
1130 GLOBAL_ROOT_UID, info, error);
1131 }
1132 }
1133 return ERR_PTR(error);
1134
1135build:
1136 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1137 build_change_hat(subj_cred, profile, name,
1138 sibling),
1139 aa_get_label(&profile->label));
1140 if (!new) {
1141 info = "label build failed";
1142 error = -ENOMEM;
1143 goto fail;
1144 } /* else if (IS_ERR) build_change_hat has logged error so return new */
1145
1146 return new;
1147}
1148
1149/**
1150 * aa_change_hat - change hat to/from subprofile
1151 * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0)
1152 * @count: number of hat names in @hats
1153 * @token: magic value to validate the hat change
1154 * @flags: flags affecting behavior of the change
1155 *
1156 * Returns %0 on success, error otherwise.
1157 *
1158 * Change to the first profile specified in @hats that exists, and store
1159 * the @hat_magic in the current task context. If the count == 0 and the
1160 * @token matches that stored in the current task context, return to the
1161 * top level profile.
1162 *
1163 * change_hat only applies to profiles in the current ns, and each profile
1164 * in the ns must make the same transition otherwise change_hat will fail.
1165 */
1166int aa_change_hat(const char *hats[], int count, u64 token, int flags)
1167{
1168 const struct cred *subj_cred;
1169 struct aa_task_ctx *ctx = task_ctx(current);
1170 struct aa_label *label, *previous, *new = NULL, *target = NULL;
1171 struct aa_profile *profile;
1172 struct aa_perms perms = {};
1173 const char *info = NULL;
1174 int error = 0;
1175
1176 /* released below */
1177 subj_cred = get_current_cred();
1178 label = aa_get_newest_cred_label(subj_cred);
1179 previous = aa_get_newest_label(ctx->previous);
1180
1181 /*
1182 * Detect no new privs being set, and store the label it
1183 * occurred under. Ideally this would happen when nnp
1184 * is set but there isn't a good way to do that yet.
1185 *
1186 * Testing for unconfined must be done before the subset test
1187 */
1188 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1189 ctx->nnp = aa_get_label(label);
1190
1191 if (unconfined(label)) {
1192 info = "unconfined can not change_hat";
1193 error = -EPERM;
1194 goto fail;
1195 }
1196
1197 if (count) {
1198 new = change_hat(subj_cred, label, hats, count, flags);
1199 AA_BUG(!new);
1200 if (IS_ERR(new)) {
1201 error = PTR_ERR(new);
1202 new = NULL;
1203 /* already audited */
1204 goto out;
1205 }
1206
1207 /* target cred is the same as current except new label */
1208 error = may_change_ptraced_domain(subj_cred, new, &info);
1209 if (error)
1210 goto fail;
1211
1212 /*
1213 * no new privs prevents domain transitions that would
1214 * reduce restrictions.
1215 */
1216 if (task_no_new_privs(current) && !unconfined(label) &&
1217 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1218 /* not an apparmor denial per se, so don't log it */
1219 AA_DEBUG("no_new_privs - change_hat denied");
1220 error = -EPERM;
1221 goto out;
1222 }
1223
1224 if (flags & AA_CHANGE_TEST)
1225 goto out;
1226
1227 target = new;
1228 error = aa_set_current_hat(new, token);
1229 if (error == -EACCES)
1230 /* kill task in case of brute force attacks */
1231 goto kill;
1232 } else if (previous && !(flags & AA_CHANGE_TEST)) {
1233 /*
1234 * no new privs prevents domain transitions that would
1235 * reduce restrictions.
1236 */
1237 if (task_no_new_privs(current) && !unconfined(label) &&
1238 !aa_label_is_unconfined_subset(previous, ctx->nnp)) {
1239 /* not an apparmor denial per se, so don't log it */
1240 AA_DEBUG("no_new_privs - change_hat denied");
1241 error = -EPERM;
1242 goto out;
1243 }
1244
1245 /* Return to saved label. Kill task if restore fails
1246 * to avoid brute force attacks
1247 */
1248 target = previous;
1249 error = aa_restore_previous_label(token);
1250 if (error) {
1251 if (error == -EACCES)
1252 goto kill;
1253 goto fail;
1254 }
1255 } /* else ignore @flags && restores when there is no saved profile */
1256
1257out:
1258 aa_put_label(new);
1259 aa_put_label(previous);
1260 aa_put_label(label);
1261 put_cred(subj_cred);
1262
1263 return error;
1264
1265kill:
1266 info = "failed token match";
1267 perms.kill = AA_MAY_CHANGEHAT;
1268
1269fail:
1270 fn_for_each_in_ns(label, profile,
1271 aa_audit_file(subj_cred, profile, &perms, OP_CHANGE_HAT,
1272 AA_MAY_CHANGEHAT, NULL, NULL, target,
1273 GLOBAL_ROOT_UID, info, error));
1274
1275 goto out;
1276}
1277
1278
1279static int change_profile_perms_wrapper(const char *op, const char *name,
1280 const struct cred *subj_cred,
1281 struct aa_profile *profile,
1282 struct aa_label *target, bool stack,
1283 u32 request, struct aa_perms *perms)
1284{
1285 struct aa_ruleset *rules = list_first_entry(&profile->rules,
1286 typeof(*rules), list);
1287 const char *info = NULL;
1288 int error = 0;
1289
1290 if (!error)
1291 error = change_profile_perms(profile, target, stack, request,
1292 rules->file->start[AA_CLASS_FILE],
1293 perms);
1294 if (error)
1295 error = aa_audit_file(subj_cred, profile, perms, op, request,
1296 name,
1297 NULL, target, GLOBAL_ROOT_UID, info,
1298 error);
1299
1300 return error;
1301}
1302
1303static const char *stack_msg = "change_profile unprivileged unconfined converted to stacking";
1304
1305/**
1306 * aa_change_profile - perform a one-way profile transition
1307 * @fqname: name of profile may include namespace (NOT NULL)
1308 * @flags: flags affecting change behavior
1309 *
1310 * Change to new profile @name. Unlike with hats, there is no way
1311 * to change back. If @name isn't specified the current profile name is
1312 * used.
1313 * If @onexec then the transition is delayed until
1314 * the next exec.
1315 *
1316 * Returns %0 on success, error otherwise.
1317 */
1318int aa_change_profile(const char *fqname, int flags)
1319{
1320 struct aa_label *label, *new = NULL, *target = NULL;
1321 struct aa_profile *profile;
1322 struct aa_perms perms = {};
1323 const char *info = NULL;
1324 const char *auditname = fqname; /* retain leading & if stack */
1325 bool stack = flags & AA_CHANGE_STACK;
1326 struct aa_task_ctx *ctx = task_ctx(current);
1327 const struct cred *subj_cred = get_current_cred();
1328 int error = 0;
1329 char *op;
1330 u32 request;
1331
1332 label = aa_get_current_label();
1333
1334 /*
1335 * Detect no new privs being set, and store the label it
1336 * occurred under. Ideally this would happen when nnp
1337 * is set but there isn't a good way to do that yet.
1338 *
1339 * Testing for unconfined must be done before the subset test
1340 */
1341 if (task_no_new_privs(current) && !unconfined(label) && !ctx->nnp)
1342 ctx->nnp = aa_get_label(label);
1343
1344 if (!fqname || !*fqname) {
1345 aa_put_label(label);
1346 AA_DEBUG("no profile name");
1347 return -EINVAL;
1348 }
1349
1350 if (flags & AA_CHANGE_ONEXEC) {
1351 request = AA_MAY_ONEXEC;
1352 if (stack)
1353 op = OP_STACK_ONEXEC;
1354 else
1355 op = OP_CHANGE_ONEXEC;
1356 } else {
1357 request = AA_MAY_CHANGE_PROFILE;
1358 if (stack)
1359 op = OP_STACK;
1360 else
1361 op = OP_CHANGE_PROFILE;
1362 }
1363
1364 /* This should move to a per profile test. Requires pushing build
1365 * into callback
1366 */
1367 if (!stack && unconfined(label) &&
1368 label == &labels_ns(label)->unconfined->label &&
1369 aa_unprivileged_unconfined_restricted &&
1370 /* TODO: refactor so this check is a fn */
1371 cap_capable(current_cred(), &init_user_ns, CAP_MAC_OVERRIDE,
1372 CAP_OPT_NOAUDIT)) {
1373 /* regardless of the request in this case apparmor
1374 * stacks against unconfined so admin set policy can't be
1375 * by-passed
1376 */
1377 stack = true;
1378 perms.audit = request;
1379 (void) fn_for_each_in_ns(label, profile,
1380 aa_audit_file(subj_cred, profile, &perms, op,
1381 request, auditname, NULL, target,
1382 GLOBAL_ROOT_UID, stack_msg, 0));
1383 perms.audit = 0;
1384 }
1385
1386 if (*fqname == '&') {
1387 stack = true;
1388 /* don't have label_parse() do stacking */
1389 fqname++;
1390 }
1391 target = aa_label_parse(label, fqname, GFP_KERNEL, true, false);
1392 if (IS_ERR(target)) {
1393 struct aa_profile *tprofile;
1394
1395 info = "label not found";
1396 error = PTR_ERR(target);
1397 target = NULL;
1398 /*
1399 * TODO: fixme using labels_profile is not right - do profile
1400 * per complain profile
1401 */
1402 if ((flags & AA_CHANGE_TEST) ||
1403 !COMPLAIN_MODE(labels_profile(label)))
1404 goto audit;
1405 /* released below */
1406 tprofile = aa_new_learning_profile(labels_profile(label), false,
1407 fqname, GFP_KERNEL);
1408 if (!tprofile) {
1409 info = "failed null profile create";
1410 error = -ENOMEM;
1411 goto audit;
1412 }
1413 target = &tprofile->label;
1414 goto check;
1415 }
1416
1417 /*
1418 * self directed transitions only apply to current policy ns
1419 * TODO: currently requiring perms for stacking and straight change
1420 * stacking doesn't strictly need this. Determine how much
1421 * we want to loosen this restriction for stacking
1422 *
1423 * if (!stack) {
1424 */
1425 error = fn_for_each_in_ns(label, profile,
1426 change_profile_perms_wrapper(op, auditname,
1427 subj_cred,
1428 profile, target, stack,
1429 request, &perms));
1430 if (error)
1431 /* auditing done in change_profile_perms_wrapper */
1432 goto out;
1433
1434 /* } */
1435
1436check:
1437 /* check if tracing task is allowed to trace target domain */
1438 error = may_change_ptraced_domain(subj_cred, target, &info);
1439 if (error && !fn_for_each_in_ns(label, profile,
1440 COMPLAIN_MODE(profile)))
1441 goto audit;
1442
1443 /* TODO: add permission check to allow this
1444 * if ((flags & AA_CHANGE_ONEXEC) && !current_is_single_threaded()) {
1445 * info = "not a single threaded task";
1446 * error = -EACCES;
1447 * goto audit;
1448 * }
1449 */
1450 if (flags & AA_CHANGE_TEST)
1451 goto out;
1452
1453 /* stacking is always a subset, so only check the nonstack case */
1454 if (!stack) {
1455 new = fn_label_build_in_ns(label, profile, GFP_KERNEL,
1456 aa_get_label(target),
1457 aa_get_label(&profile->label));
1458 /*
1459 * no new privs prevents domain transitions that would
1460 * reduce restrictions.
1461 */
1462 if (task_no_new_privs(current) && !unconfined(label) &&
1463 !aa_label_is_unconfined_subset(new, ctx->nnp)) {
1464 /* not an apparmor denial per se, so don't log it */
1465 AA_DEBUG("no_new_privs - change_hat denied");
1466 error = -EPERM;
1467 goto out;
1468 }
1469 }
1470
1471 if (!(flags & AA_CHANGE_ONEXEC)) {
1472 /* only transition profiles in the current ns */
1473 if (stack)
1474 new = aa_label_merge(label, target, GFP_KERNEL);
1475 if (IS_ERR_OR_NULL(new)) {
1476 info = "failed to build target label";
1477 if (!new)
1478 error = -ENOMEM;
1479 else
1480 error = PTR_ERR(new);
1481 new = NULL;
1482 perms.allow = 0;
1483 goto audit;
1484 }
1485 error = aa_replace_current_label(new);
1486 } else {
1487 if (new) {
1488 aa_put_label(new);
1489 new = NULL;
1490 }
1491
1492 /* full transition will be built in exec path */
1493 aa_set_current_onexec(target, stack);
1494 }
1495
1496audit:
1497 error = fn_for_each_in_ns(label, profile,
1498 aa_audit_file(subj_cred,
1499 profile, &perms, op, request, auditname,
1500 NULL, new ? new : target,
1501 GLOBAL_ROOT_UID, info, error));
1502
1503out:
1504 aa_put_label(new);
1505 aa_put_label(target);
1506 aa_put_label(label);
1507 put_cred(subj_cred);
1508
1509 return error;
1510}