mount.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * AppArmor security module
  4 *
  5 * This file contains AppArmor mediation of files
  6 *
  7 * Copyright (C) 1998-2008 Novell/SUSE
  8 * Copyright 2009-2017 Canonical Ltd.
  9 */
 10
 11#include <linux/fs.h>
 12#include <linux/mount.h>
 13#include <linux/namei.h>
 14#include <uapi/linux/mount.h>
 15
 16#include "include/apparmor.h"
 17#include "include/audit.h"
 18#include "include/cred.h"
 19#include "include/domain.h"
 20#include "include/file.h"
 21#include "include/match.h"
 22#include "include/mount.h"
 23#include "include/path.h"
 24#include "include/policy.h"
 25
 26
 27static void audit_mnt_flags(struct audit_buffer *ab, unsigned long flags)
 28{
 29	if (flags & MS_RDONLY)
 30		audit_log_format(ab, "ro");
 31	else
 32		audit_log_format(ab, "rw");
 33	if (flags & MS_NOSUID)
 34		audit_log_format(ab, ", nosuid");
 35	if (flags & MS_NODEV)
 36		audit_log_format(ab, ", nodev");
 37	if (flags & MS_NOEXEC)
 38		audit_log_format(ab, ", noexec");
 39	if (flags & MS_SYNCHRONOUS)
 40		audit_log_format(ab, ", sync");
 41	if (flags & MS_REMOUNT)
 42		audit_log_format(ab, ", remount");
 43	if (flags & MS_MANDLOCK)
 44		audit_log_format(ab, ", mand");
 45	if (flags & MS_DIRSYNC)
 46		audit_log_format(ab, ", dirsync");
 47	if (flags & MS_NOSYMFOLLOW)
 48		audit_log_format(ab, ", nosymfollow");
 49	if (flags & MS_NOATIME)
 50		audit_log_format(ab, ", noatime");
 51	if (flags & MS_NODIRATIME)
 52		audit_log_format(ab, ", nodiratime");
 53	if (flags & MS_BIND)
 54		audit_log_format(ab, flags & MS_REC ? ", rbind" : ", bind");
 55	if (flags & MS_MOVE)
 56		audit_log_format(ab, ", move");
 57	if (flags & MS_SILENT)
 58		audit_log_format(ab, ", silent");
 59	if (flags & MS_POSIXACL)
 60		audit_log_format(ab, ", acl");
 61	if (flags & MS_UNBINDABLE)
 62		audit_log_format(ab, flags & MS_REC ? ", runbindable" :
 63				 ", unbindable");
 64	if (flags & MS_PRIVATE)
 65		audit_log_format(ab, flags & MS_REC ? ", rprivate" :
 66				 ", private");
 67	if (flags & MS_SLAVE)
 68		audit_log_format(ab, flags & MS_REC ? ", rslave" :
 69				 ", slave");
 70	if (flags & MS_SHARED)
 71		audit_log_format(ab, flags & MS_REC ? ", rshared" :
 72				 ", shared");
 73	if (flags & MS_RELATIME)
 74		audit_log_format(ab, ", relatime");
 75	if (flags & MS_I_VERSION)
 76		audit_log_format(ab, ", iversion");
 77	if (flags & MS_STRICTATIME)
 78		audit_log_format(ab, ", strictatime");
 79	if (flags & MS_NOUSER)
 80		audit_log_format(ab, ", nouser");
 81}
 82
 83/**
 84 * audit_cb - call back for mount specific audit fields
 85 * @ab: audit_buffer  (NOT NULL)
 86 * @va: audit struct to audit values of  (NOT NULL)
 87 */
 88static void audit_cb(struct audit_buffer *ab, void *va)
 89{
 90	struct common_audit_data *sa = va;
 91	struct apparmor_audit_data *ad = aad(sa);
 92
 93	if (ad->mnt.type) {
 94		audit_log_format(ab, " fstype=");
 95		audit_log_untrustedstring(ab, ad->mnt.type);
 96	}
 97	if (ad->mnt.src_name) {
 98		audit_log_format(ab, " srcname=");
 99		audit_log_untrustedstring(ab, ad->mnt.src_name);
100	}
101	if (ad->mnt.trans) {
102		audit_log_format(ab, " trans=");
103		audit_log_untrustedstring(ab, ad->mnt.trans);
104	}
105	if (ad->mnt.flags) {
106		audit_log_format(ab, " flags=\"");
107		audit_mnt_flags(ab, ad->mnt.flags);
108		audit_log_format(ab, "\"");
109	}
110	if (ad->mnt.data) {
111		audit_log_format(ab, " options=");
112		audit_log_untrustedstring(ab, ad->mnt.data);
113	}
114}
115
116/**
117 * audit_mount - handle the auditing of mount operations
118 * @subj_cred: cred of the subject
119 * @profile: the profile being enforced  (NOT NULL)
120 * @op: operation being mediated (NOT NULL)
121 * @name: name of object being mediated (MAYBE NULL)
122 * @src_name: src_name of object being mediated (MAYBE_NULL)
123 * @type: type of filesystem (MAYBE_NULL)
124 * @trans: name of trans (MAYBE NULL)
125 * @flags: filesystem independent mount flags
126 * @data: filesystem mount flags
127 * @request: permissions requested
128 * @perms: the permissions computed for the request (NOT NULL)
129 * @info: extra information message (MAYBE NULL)
130 * @error: 0 if operation allowed else failure error code
131 *
132 * Returns: %0 or error on failure
133 */
134static int audit_mount(const struct cred *subj_cred,
135		       struct aa_profile *profile, const char *op,
136		       const char *name, const char *src_name,
137		       const char *type, const char *trans,
138		       unsigned long flags, const void *data, u32 request,
139		       struct aa_perms *perms, const char *info, int error)
140{
141	int audit_type = AUDIT_APPARMOR_AUTO;
142	DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_MOUNT, op);
143
144	if (likely(!error)) {
145		u32 mask = perms->audit;
146
147		if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
148			mask = 0xffff;
149
150		/* mask off perms that are not being force audited */
151		request &= mask;
152
153		if (likely(!request))
154			return 0;
155		audit_type = AUDIT_APPARMOR_AUDIT;
156	} else {
157		/* only report permissions that were denied */
158		request = request & ~perms->allow;
159
160		if (request & perms->kill)
161			audit_type = AUDIT_APPARMOR_KILL;
162
163		/* quiet known rejects, assumes quiet and kill do not overlap */
164		if ((request & perms->quiet) &&
165		    AUDIT_MODE(profile) != AUDIT_NOQUIET &&
166		    AUDIT_MODE(profile) != AUDIT_ALL)
167			request &= ~perms->quiet;
168
169		if (!request)
170			return error;
171	}
172
173	ad.subj_cred = subj_cred;
174	ad.name = name;
175	ad.mnt.src_name = src_name;
176	ad.mnt.type = type;
177	ad.mnt.trans = trans;
178	ad.mnt.flags = flags;
179	if (data && (perms->audit & AA_AUDIT_DATA))
180		ad.mnt.data = data;
181	ad.info = info;
182	ad.error = error;
183
184	return aa_audit(audit_type, profile, &ad, audit_cb);
185}
186
187/**
188 * match_mnt_flags - Do an ordered match on mount flags
189 * @dfa: dfa to match against
190 * @state: state to start in
191 * @flags: mount flags to match against
192 *
193 * Mount flags are encoded as an ordered match. This is done instead of
194 * checking against a simple bitmask, to allow for logical operations
195 * on the flags.
196 *
197 * Returns: next state after flags match
198 */
199static aa_state_t match_mnt_flags(struct aa_dfa *dfa, aa_state_t state,
200				    unsigned long flags)
201{
202	unsigned int i;
203
204	for (i = 0; i <= 31 ; ++i) {
205		if ((1 << i) & flags)
206			state = aa_dfa_next(dfa, state, i + 1);
207	}
208
209	return state;
210}
211
212static const char * const mnt_info_table[] = {
213	"match succeeded",
214	"failed mntpnt match",
215	"failed srcname match",
216	"failed type match",
217	"failed flags match",
218	"failed data match",
219	"failed perms check"
220};
221
222/*
223 * Returns 0 on success else element that match failed in, this is the
224 * index into the mnt_info_table above
225 */
226static int do_match_mnt(struct aa_policydb *policy, aa_state_t start,
227			const char *mntpnt, const char *devname,
228			const char *type, unsigned long flags,
229			void *data, bool binary, struct aa_perms *perms)
230{
231	aa_state_t state;
232
233	AA_BUG(!policy);
234	AA_BUG(!policy->dfa);
235	AA_BUG(!policy->perms);
236	AA_BUG(!perms);
237
238	state = aa_dfa_match(policy->dfa, start, mntpnt);
239	state = aa_dfa_null_transition(policy->dfa, state);
240	if (!state)
241		return 1;
242
243	if (devname)
244		state = aa_dfa_match(policy->dfa, state, devname);
245	state = aa_dfa_null_transition(policy->dfa, state);
246	if (!state)
247		return 2;
248
249	if (type)
250		state = aa_dfa_match(policy->dfa, state, type);
251	state = aa_dfa_null_transition(policy->dfa, state);
252	if (!state)
253		return 3;
254
255	state = match_mnt_flags(policy->dfa, state, flags);
256	if (!state)
257		return 4;
258	*perms = *aa_lookup_perms(policy, state);
259	if (perms->allow & AA_MAY_MOUNT)
260		return 0;
261
262	/* only match data if not binary and the DFA flags data is expected */
263	if (data && !binary && (perms->allow & AA_MNT_CONT_MATCH)) {
264		state = aa_dfa_null_transition(policy->dfa, state);
265		if (!state)
266			return 4;
267
268		state = aa_dfa_match(policy->dfa, state, data);
269		if (!state)
270			return 5;
271		*perms = *aa_lookup_perms(policy, state);
272		if (perms->allow & AA_MAY_MOUNT)
273			return 0;
274	}
275
276	/* failed at perms check, don't confuse with flags match */
277	return 6;
278}
279
280
281static int path_flags(struct aa_profile *profile, const struct path *path)
282{
283	AA_BUG(!profile);
284	AA_BUG(!path);
285
286	return profile->path_flags |
287		(S_ISDIR(path->dentry->d_inode->i_mode) ? PATH_IS_DIR : 0);
288}
289
290/**
291 * match_mnt_path_str - handle path matching for mount
292 * @subj_cred: cred of confined subject
293 * @profile: the confining profile
294 * @mntpath: for the mntpnt (NOT NULL)
295 * @buffer: buffer to be used to lookup mntpath
296 * @devname: string for the devname/src_name (MAY BE NULL OR ERRPTR)
297 * @type: string for the dev type (MAYBE NULL)
298 * @flags: mount flags to match
299 * @data: fs mount data (MAYBE NULL)
300 * @binary: whether @data is binary
301 * @devinfo: error str if (IS_ERR(@devname))
302 *
303 * Returns: 0 on success else error
304 */
305static int match_mnt_path_str(const struct cred *subj_cred,
306			      struct aa_profile *profile,
307			      const struct path *mntpath, char *buffer,
308			      const char *devname, const char *type,
309			      unsigned long flags, void *data, bool binary,
310			      const char *devinfo)
311{
312	struct aa_perms perms = { };
313	const char *mntpnt = NULL, *info = NULL;
314	struct aa_ruleset *rules = profile->label.rules[0];
315	int pos, error;
316
317	AA_BUG(!profile);
318	AA_BUG(!mntpath);
319	AA_BUG(!buffer);
320
321	if (!RULE_MEDIATES(rules, AA_CLASS_MOUNT))
322		return 0;
323
324	error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer,
325			     &mntpnt, &info, profile->disconnected);
326	if (error)
327		goto audit;
328	if (IS_ERR(devname)) {
329		error = PTR_ERR(devname);
330		devname = NULL;
331		info = devinfo;
332		goto audit;
333	}
334
335	error = -EACCES;
336	pos = do_match_mnt(rules->policy,
337			   rules->policy->start[AA_CLASS_MOUNT],
338			   mntpnt, devname, type, flags, data, binary, &perms);
339	if (pos) {
340		info = mnt_info_table[pos];
341		goto audit;
342	}
343	error = 0;
344
345audit:
346	return audit_mount(subj_cred, profile, OP_MOUNT, mntpnt, devname,
347			   type, NULL,
348			   flags, data, AA_MAY_MOUNT, &perms, info, error);
349}
350
351/**
352 * match_mnt - handle path matching for mount
353 * @subj_cred: cred of the subject
354 * @profile: the confining profile
355 * @path: for the mntpnt (NOT NULL)
356 * @buffer: buffer to be used to lookup mntpath
357 * @devpath: path devname/src_name (MAYBE NULL)
358 * @devbuffer: buffer to be used to lookup devname/src_name
359 * @type: string for the dev type (MAYBE NULL)
360 * @flags: mount flags to match
361 * @data: fs mount data (MAYBE NULL)
362 * @binary: whether @data is binary
363 *
364 * Returns: 0 on success else error
365 */
366static int match_mnt(const struct cred *subj_cred,
367		     struct aa_profile *profile, const struct path *path,
368		     char *buffer, const struct path *devpath, char *devbuffer,
369		     const char *type, unsigned long flags, void *data,
370		     bool binary)
371{
372	const char *devname = NULL, *info = NULL;
373	struct aa_ruleset *rules = profile->label.rules[0];
374	int error = -EACCES;
375
376	AA_BUG(!profile);
377	AA_BUG(devpath && !devbuffer);
378
379	if (!RULE_MEDIATES(rules, AA_CLASS_MOUNT))
380		return 0;
381
382	if (devpath) {
383		error = aa_path_name(devpath, path_flags(profile, devpath),
384				     devbuffer, &devname, &info,
385				     profile->disconnected);
386		if (error)
387			devname = ERR_PTR(error);
388	}
389
390	return match_mnt_path_str(subj_cred, profile, path, buffer, devname,
391				  type, flags, data, binary, info);
392}
393
394int aa_remount(const struct cred *subj_cred,
395	       struct aa_label *label, const struct path *path,
396	       unsigned long flags, void *data)
397{
398	struct aa_profile *profile;
399	char *buffer = NULL;
400	bool binary;
401	int error;
402
403	AA_BUG(!label);
404	AA_BUG(!path);
405
406	binary = path->dentry->d_sb->s_type->fs_flags & FS_BINARY_MOUNTDATA;
407
408	buffer = aa_get_buffer(false);
409	if (!buffer)
410		return -ENOMEM;
411	error = fn_for_each_confined(label, profile,
412			match_mnt(subj_cred, profile, path, buffer, NULL,
413				  NULL, NULL,
414				  flags, data, binary));
415	aa_put_buffer(buffer);
416
417	return error;
418}
419
420int aa_bind_mount(const struct cred *subj_cred,
421		  struct aa_label *label, const struct path *path,
422		  const char *dev_name, unsigned long flags)
423{
424	struct aa_profile *profile;
425	char *buffer = NULL, *old_buffer = NULL;
426	struct path old_path;
427	int error;
428
429	AA_BUG(!label);
430	AA_BUG(!path);
431
432	if (!dev_name || !*dev_name)
433		return -EINVAL;
434
435	flags &= MS_REC | MS_BIND;
436
437	error = kern_path(dev_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path);
438	if (error)
439		return error;
440
441	buffer = aa_get_buffer(false);
442	old_buffer = aa_get_buffer(false);
443	error = -ENOMEM;
444	if (!buffer || !old_buffer)
445		goto out;
446
447	error = fn_for_each_confined(label, profile,
448			match_mnt(subj_cred, profile, path, buffer, &old_path,
449				  old_buffer, NULL, flags, NULL, false));
450out:
451	aa_put_buffer(buffer);
452	aa_put_buffer(old_buffer);
453	path_put(&old_path);
454
455	return error;
456}
457
458int aa_mount_change_type(const struct cred *subj_cred,
459			 struct aa_label *label, const struct path *path,
460			 unsigned long flags)
461{
462	struct aa_profile *profile;
463	char *buffer = NULL;
464	int error;
465
466	AA_BUG(!label);
467	AA_BUG(!path);
468
469	/* These are the flags allowed by do_change_type() */
470	flags &= (MS_REC | MS_SILENT | MS_SHARED | MS_PRIVATE | MS_SLAVE |
471		  MS_UNBINDABLE);
472
473	buffer = aa_get_buffer(false);
474	if (!buffer)
475		return -ENOMEM;
476	error = fn_for_each_confined(label, profile,
477			match_mnt(subj_cred, profile, path, buffer, NULL,
478				  NULL, NULL,
479				  flags, NULL, false));
480	aa_put_buffer(buffer);
481
482	return error;
483}
484
485int aa_move_mount(const struct cred *subj_cred,
486		  struct aa_label *label, const struct path *from_path,
487		  const struct path *to_path)
488{
489	struct aa_profile *profile;
490	char *to_buffer = NULL, *from_buffer = NULL;
491	int error;
492
493	AA_BUG(!label);
494	AA_BUG(!from_path);
495	AA_BUG(!to_path);
496
497	to_buffer = aa_get_buffer(false);
498	from_buffer = aa_get_buffer(false);
499	error = -ENOMEM;
500	if (!to_buffer || !from_buffer)
501		goto out;
502
503	if (!our_mnt(from_path->mnt))
504		/* moving a mount detached from the namespace */
505		from_path = NULL;
506	error = fn_for_each_confined(label, profile,
507			match_mnt(subj_cred, profile, to_path, to_buffer,
508				  from_path, from_buffer,
509				  NULL, MS_MOVE, NULL, false));
510out:
511	aa_put_buffer(to_buffer);
512	aa_put_buffer(from_buffer);
513
514	return error;
515}
516
517int aa_move_mount_old(const struct cred *subj_cred, struct aa_label *label,
518		      const struct path *path, const char *orig_name)
519{
520	struct path old_path;
521	int error;
522
523	if (!orig_name || !*orig_name)
524		return -EINVAL;
525	error = kern_path(orig_name, LOOKUP_FOLLOW, &old_path);
526	if (error)
527		return error;
528
529	error = aa_move_mount(subj_cred, label, &old_path, path);
530	path_put(&old_path);
531
532	return error;
533}
534
535int aa_new_mount(const struct cred *subj_cred, struct aa_label *label,
536		 const char *dev_name, const struct path *path,
537		 const char *type, unsigned long flags, void *data)
538{
539	struct aa_profile *profile;
540	char *buffer = NULL, *dev_buffer = NULL;
541	bool binary = true;
542	int error;
543	int requires_dev = 0;
544	struct path tmp_path, *dev_path = NULL;
545
546	AA_BUG(!label);
547	AA_BUG(!path);
548
549	if (type) {
550		struct file_system_type *fstype;
551
552		fstype = get_fs_type(type);
553		if (!fstype)
554			return -ENODEV;
555		binary = fstype->fs_flags & FS_BINARY_MOUNTDATA;
556		requires_dev = fstype->fs_flags & FS_REQUIRES_DEV;
557		put_filesystem(fstype);
558
559		if (requires_dev) {
560			if (!dev_name || !*dev_name)
561				return -ENOENT;
562
563			error = kern_path(dev_name, LOOKUP_FOLLOW, &tmp_path);
564			if (error)
565				return error;
566			dev_path = &tmp_path;
567		}
568	}
569
570	buffer = aa_get_buffer(false);
571	if (!buffer) {
572		error = -ENOMEM;
573		goto out;
574	}
575	if (dev_path) {
576		dev_buffer = aa_get_buffer(false);
577		if (!dev_buffer) {
578			error = -ENOMEM;
579			goto out;
580		}
581		error = fn_for_each_confined(label, profile,
582				match_mnt(subj_cred, profile, path, buffer,
583					  dev_path, dev_buffer,
584				  type, flags, data, binary));
585	} else {
586		error = fn_for_each_confined(label, profile,
587				match_mnt_path_str(subj_cred, profile, path,
588					buffer, dev_name,
589					type, flags, data, binary, NULL));
590	}
591
592out:
593	aa_put_buffer(buffer);
594	aa_put_buffer(dev_buffer);
595	if (dev_path)
596		path_put(dev_path);
597
598	return error;
599}
600
601static int profile_umount(const struct cred *subj_cred,
602			  struct aa_profile *profile, const struct path *path,
603			  char *buffer)
604{
605	struct aa_ruleset *rules = profile->label.rules[0];
606	struct aa_perms perms = { };
607	const char *name = NULL, *info = NULL;
608	aa_state_t state;
609	int error;
610
611	AA_BUG(!profile);
612	AA_BUG(!path);
613
614	if (!RULE_MEDIATES(rules, AA_CLASS_MOUNT))
615		return 0;
616
617	error = aa_path_name(path, path_flags(profile, path), buffer, &name,
618			     &info, profile->disconnected);
619	if (error)
620		goto audit;
621
622	state = aa_dfa_match(rules->policy->dfa,
623			     rules->policy->start[AA_CLASS_MOUNT],
624			     name);
625	perms = *aa_lookup_perms(rules->policy, state);
626	if (AA_MAY_UMOUNT & ~perms.allow)
627		error = -EACCES;
628
629audit:
630	return audit_mount(subj_cred, profile, OP_UMOUNT, name, NULL, NULL,
631			   NULL, 0, NULL,
632			   AA_MAY_UMOUNT, &perms, info, error);
633}
634
635int aa_umount(const struct cred *subj_cred, struct aa_label *label,
636	      struct vfsmount *mnt, int flags)
637{
638	struct aa_profile *profile;
639	char *buffer = NULL;
640	int error;
641	struct path path = { .mnt = mnt, .dentry = mnt->mnt_root };
642
643	AA_BUG(!label);
644	AA_BUG(!mnt);
645
646	buffer = aa_get_buffer(false);
647	if (!buffer)
648		return -ENOMEM;
649
650	error = fn_for_each_confined(label, profile,
651			profile_umount(subj_cred, profile, &path, buffer));
652	aa_put_buffer(buffer);
653
654	return error;
655}
656
657/* helper fn for transition on pivotroot
658 *
659 * Returns: label for transition or ERR_PTR. Does not return NULL
660 */
661static struct aa_label *build_pivotroot(const struct cred *subj_cred,
662					struct aa_profile *profile,
663					const struct path *new_path,
664					char *new_buffer,
665					const struct path *old_path,
666					char *old_buffer)
667{
668	struct aa_ruleset *rules = profile->label.rules[0];
669	const char *old_name, *new_name = NULL, *info = NULL;
670	const char *trans_name = NULL;
671	struct aa_perms perms = { };
672	aa_state_t state;
673	int error;
674
675	AA_BUG(!profile);
676	AA_BUG(!new_path);
677	AA_BUG(!old_path);
678
679	if (profile_unconfined(profile) ||
680	    !RULE_MEDIATES(rules, AA_CLASS_MOUNT))
681		return aa_get_newest_label(&profile->label);
682
683	error = aa_path_name(old_path, path_flags(profile, old_path),
684			     old_buffer, &old_name, &info,
685			     profile->disconnected);
686	if (error)
687		goto audit;
688	error = aa_path_name(new_path, path_flags(profile, new_path),
689			     new_buffer, &new_name, &info,
690			     profile->disconnected);
691	if (error)
692		goto audit;
693
694	error = -EACCES;
695	state = aa_dfa_match(rules->policy->dfa,
696			     rules->policy->start[AA_CLASS_MOUNT],
697			     new_name);
698	state = aa_dfa_null_transition(rules->policy->dfa, state);
699	state = aa_dfa_match(rules->policy->dfa, state, old_name);
700	perms = *aa_lookup_perms(rules->policy, state);
701
702	if (AA_MAY_PIVOTROOT & perms.allow)
703		error = 0;
704
705audit:
706	error = audit_mount(subj_cred, profile, OP_PIVOTROOT, new_name,
707			    old_name,
708			    NULL, trans_name, 0, NULL, AA_MAY_PIVOTROOT,
709			    &perms, info, error);
710	if (error)
711		return ERR_PTR(error);
712
713	return aa_get_newest_label(&profile->label);
714}
715
716int aa_pivotroot(const struct cred *subj_cred, struct aa_label *label,
717		 const struct path *old_path,
718		 const struct path *new_path)
719{
720	struct aa_profile *profile;
721	struct aa_label *target = NULL;
722	char *old_buffer = NULL, *new_buffer = NULL, *info = NULL;
723	int error;
724
725	AA_BUG(!label);
726	AA_BUG(!old_path);
727	AA_BUG(!new_path);
728
729	old_buffer = aa_get_buffer(false);
730	new_buffer = aa_get_buffer(false);
731	error = -ENOMEM;
732	if (!old_buffer || !new_buffer)
733		goto out;
734	target = fn_label_build(label, profile, GFP_KERNEL,
735			build_pivotroot(subj_cred, profile, new_path,
736					new_buffer,
737					old_path, old_buffer));
738	if (!target) {
739		info = "label build failed";
740		error = -ENOMEM;
741		goto fail;
742	} else if (!IS_ERR(target)) {
743		error = aa_replace_current_label(target);
744		if (error) {
745			/* TODO: audit target */
746			aa_put_label(target);
747			goto out;
748		}
749		aa_put_label(target);
750	} else
751		/* already audited error */
752		error = PTR_ERR(target);
753out:
754	aa_put_buffer(old_buffer);
755	aa_put_buffer(new_buffer);
756
757	return error;
758
759fail:
760	/* TODO: add back in auditing of new_name and old_name */
761	error = fn_for_each(label, profile,
762			audit_mount(subj_cred, profile, OP_PIVOTROOT,
763				    NULL /*new_name */,
764				    NULL /* old_name */,
765				    NULL, NULL,
766				    0, NULL, AA_MAY_PIVOTROOT, &nullperms, info,
767				    error));
768	goto out;
769}