1 // SPDX-License-Identifier: GPL-2.0-only
3 * AppArmor security module
5 * This file contains AppArmor mediation of files
7 * Copyright (C) 1998-2008 Novell/SUSE
8 * Copyright 2009-2017 Canonical Ltd.
12 #include <linux/mount.h>
13 #include <linux/namei.h>
14 #include <uapi/linux/mount.h>
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"
27 static void audit_mnt_flags(struct audit_buffer *ab, unsigned long flags)
29 if (flags & MS_RDONLY)
30 audit_log_format(ab, "ro");
32 audit_log_format(ab, "rw");
33 if (flags & MS_NOSUID)
34 audit_log_format(ab, ", nosuid");
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_NOATIME)
48 audit_log_format(ab, ", noatime");
49 if (flags & MS_NODIRATIME)
50 audit_log_format(ab, ", nodiratime");
52 audit_log_format(ab, flags & MS_REC ? ", rbind" : ", bind");
54 audit_log_format(ab, ", move");
55 if (flags & MS_SILENT)
56 audit_log_format(ab, ", silent");
57 if (flags & MS_POSIXACL)
58 audit_log_format(ab, ", acl");
59 if (flags & MS_UNBINDABLE)
60 audit_log_format(ab, flags & MS_REC ? ", runbindable" :
62 if (flags & MS_PRIVATE)
63 audit_log_format(ab, flags & MS_REC ? ", rprivate" :
66 audit_log_format(ab, flags & MS_REC ? ", rslave" :
68 if (flags & MS_SHARED)
69 audit_log_format(ab, flags & MS_REC ? ", rshared" :
71 if (flags & MS_RELATIME)
72 audit_log_format(ab, ", relatime");
73 if (flags & MS_I_VERSION)
74 audit_log_format(ab, ", iversion");
75 if (flags & MS_STRICTATIME)
76 audit_log_format(ab, ", strictatime");
77 if (flags & MS_NOUSER)
78 audit_log_format(ab, ", nouser");
82 * audit_cb - call back for mount specific audit fields
83 * @ab: audit_buffer (NOT NULL)
84 * @va: audit struct to audit values of (NOT NULL)
86 static void audit_cb(struct audit_buffer *ab, void *va)
88 struct common_audit_data *sa = va;
90 if (aad(sa)->mnt.type) {
91 audit_log_format(ab, " fstype=");
92 audit_log_untrustedstring(ab, aad(sa)->mnt.type);
94 if (aad(sa)->mnt.src_name) {
95 audit_log_format(ab, " srcname=");
96 audit_log_untrustedstring(ab, aad(sa)->mnt.src_name);
98 if (aad(sa)->mnt.trans) {
99 audit_log_format(ab, " trans=");
100 audit_log_untrustedstring(ab, aad(sa)->mnt.trans);
102 if (aad(sa)->mnt.flags) {
103 audit_log_format(ab, " flags=\"");
104 audit_mnt_flags(ab, aad(sa)->mnt.flags);
105 audit_log_format(ab, "\"");
107 if (aad(sa)->mnt.data) {
108 audit_log_format(ab, " options=");
109 audit_log_untrustedstring(ab, aad(sa)->mnt.data);
114 * audit_mount - handle the auditing of mount operations
115 * @profile: the profile being enforced (NOT NULL)
116 * @op: operation being mediated (NOT NULL)
117 * @name: name of object being mediated (MAYBE NULL)
118 * @src_name: src_name of object being mediated (MAYBE_NULL)
119 * @type: type of filesystem (MAYBE_NULL)
120 * @trans: name of trans (MAYBE NULL)
121 * @flags: filesystem independent mount flags
122 * @data: filesystem mount flags
123 * @request: permissions requested
124 * @perms: the permissions computed for the request (NOT NULL)
125 * @info: extra information message (MAYBE NULL)
126 * @error: 0 if operation allowed else failure error code
128 * Returns: %0 or error on failure
130 static int audit_mount(struct aa_profile *profile, const char *op,
131 const char *name, const char *src_name,
132 const char *type, const char *trans,
133 unsigned long flags, const void *data, u32 request,
134 struct aa_perms *perms, const char *info, int error)
136 int audit_type = AUDIT_APPARMOR_AUTO;
137 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, op);
139 if (likely(!error)) {
140 u32 mask = perms->audit;
142 if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
145 /* mask off perms that are not being force audited */
148 if (likely(!request))
150 audit_type = AUDIT_APPARMOR_AUDIT;
152 /* only report permissions that were denied */
153 request = request & ~perms->allow;
155 if (request & perms->kill)
156 audit_type = AUDIT_APPARMOR_KILL;
158 /* quiet known rejects, assumes quiet and kill do not overlap */
159 if ((request & perms->quiet) &&
160 AUDIT_MODE(profile) != AUDIT_NOQUIET &&
161 AUDIT_MODE(profile) != AUDIT_ALL)
162 request &= ~perms->quiet;
168 aad(&sa)->name = name;
169 aad(&sa)->mnt.src_name = src_name;
170 aad(&sa)->mnt.type = type;
171 aad(&sa)->mnt.trans = trans;
172 aad(&sa)->mnt.flags = flags;
173 if (data && (perms->audit & AA_AUDIT_DATA))
174 aad(&sa)->mnt.data = data;
175 aad(&sa)->info = info;
176 aad(&sa)->error = error;
178 return aa_audit(audit_type, profile, &sa, audit_cb);
182 * match_mnt_flags - Do an ordered match on mount flags
183 * @dfa: dfa to match against
184 * @state: state to start in
185 * @flags: mount flags to match against
187 * Mount flags are encoded as an ordered match. This is done instead of
188 * checking against a simple bitmask, to allow for logical operations
191 * Returns: next state after flags match
193 static unsigned int match_mnt_flags(struct aa_dfa *dfa, unsigned int state,
198 for (i = 0; i <= 31 ; ++i) {
199 if ((1 << i) & flags)
200 state = aa_dfa_next(dfa, state, i + 1);
207 * compute_mnt_perms - compute mount permission associated with @state
208 * @dfa: dfa to match against (NOT NULL)
209 * @state: state match finished in
211 * Returns: mount permissions
213 static struct aa_perms compute_mnt_perms(struct aa_dfa *dfa,
216 struct aa_perms perms = {
217 .allow = dfa_user_allow(dfa, state),
218 .audit = dfa_user_audit(dfa, state),
219 .quiet = dfa_user_quiet(dfa, state),
220 .xindex = dfa_user_xindex(dfa, state),
226 static const char * const mnt_info_table[] = {
228 "failed mntpnt match",
229 "failed srcname match",
231 "failed flags match",
237 * Returns 0 on success else element that match failed in, this is the
238 * index into the mnt_info_table above
240 static int do_match_mnt(struct aa_dfa *dfa, unsigned int start,
241 const char *mntpnt, const char *devname,
242 const char *type, unsigned long flags,
243 void *data, bool binary, struct aa_perms *perms)
250 state = aa_dfa_match(dfa, start, mntpnt);
251 state = aa_dfa_null_transition(dfa, state);
256 state = aa_dfa_match(dfa, state, devname);
257 state = aa_dfa_null_transition(dfa, state);
262 state = aa_dfa_match(dfa, state, type);
263 state = aa_dfa_null_transition(dfa, state);
267 state = match_mnt_flags(dfa, state, flags);
270 *perms = compute_mnt_perms(dfa, state);
271 if (perms->allow & AA_MAY_MOUNT)
274 /* only match data if not binary and the DFA flags data is expected */
275 if (data && !binary && (perms->allow & AA_MNT_CONT_MATCH)) {
276 state = aa_dfa_null_transition(dfa, state);
280 state = aa_dfa_match(dfa, state, data);
283 *perms = compute_mnt_perms(dfa, state);
284 if (perms->allow & AA_MAY_MOUNT)
288 /* failed at perms check, don't confuse with flags match */
293 static int path_flags(struct aa_profile *profile, const struct path *path)
298 return profile->path_flags |
299 (S_ISDIR(path->dentry->d_inode->i_mode) ? PATH_IS_DIR : 0);
303 * match_mnt_path_str - handle path matching for mount
304 * @profile: the confining profile
305 * @mntpath: for the mntpnt (NOT NULL)
306 * @buffer: buffer to be used to lookup mntpath
307 * @devnme: string for the devname/src_name (MAY BE NULL OR ERRPTR)
308 * @type: string for the dev type (MAYBE NULL)
309 * @flags: mount flags to match
310 * @data: fs mount data (MAYBE NULL)
311 * @binary: whether @data is binary
312 * @devinfo: error str if (IS_ERR(@devname))
314 * Returns: 0 on success else error
316 static int match_mnt_path_str(struct aa_profile *profile,
317 const struct path *mntpath, char *buffer,
318 const char *devname, const char *type,
319 unsigned long flags, void *data, bool binary,
322 struct aa_perms perms = { };
323 const char *mntpnt = NULL, *info = NULL;
330 if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
333 error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer,
334 &mntpnt, &info, profile->disconnected);
337 if (IS_ERR(devname)) {
338 error = PTR_ERR(devname);
345 pos = do_match_mnt(profile->policy.dfa,
346 profile->policy.start[AA_CLASS_MOUNT],
347 mntpnt, devname, type, flags, data, binary, &perms);
349 info = mnt_info_table[pos];
355 return audit_mount(profile, OP_MOUNT, mntpnt, devname, type, NULL,
356 flags, data, AA_MAY_MOUNT, &perms, info, error);
360 * match_mnt - handle path matching for mount
361 * @profile: the confining profile
362 * @mntpath: for the mntpnt (NOT NULL)
363 * @buffer: buffer to be used to lookup mntpath
364 * @devpath: path devname/src_name (MAYBE NULL)
365 * @devbuffer: buffer to be used to lookup devname/src_name
366 * @type: string for the dev type (MAYBE NULL)
367 * @flags: mount flags to match
368 * @data: fs mount data (MAYBE NULL)
369 * @binary: whether @data is binary
371 * Returns: 0 on success else error
373 static int match_mnt(struct aa_profile *profile, const struct path *path,
374 char *buffer, struct path *devpath, char *devbuffer,
375 const char *type, unsigned long flags, void *data,
378 const char *devname = NULL, *info = NULL;
382 AA_BUG(devpath && !devbuffer);
384 if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
388 error = aa_path_name(devpath, path_flags(profile, devpath),
389 devbuffer, &devname, &info,
390 profile->disconnected);
392 devname = ERR_PTR(error);
395 return match_mnt_path_str(profile, path, buffer, devname, type, flags,
399 int aa_remount(struct aa_label *label, const struct path *path,
400 unsigned long flags, void *data)
402 struct aa_profile *profile;
410 binary = path->dentry->d_sb->s_type->fs_flags & FS_BINARY_MOUNTDATA;
413 error = fn_for_each_confined(label, profile,
414 match_mnt(profile, path, buffer, NULL, NULL, NULL,
415 flags, data, binary));
421 int aa_bind_mount(struct aa_label *label, const struct path *path,
422 const char *dev_name, unsigned long flags)
424 struct aa_profile *profile;
425 char *buffer = NULL, *old_buffer = NULL;
426 struct path old_path;
432 if (!dev_name || !*dev_name)
435 flags &= MS_REC | MS_BIND;
437 error = kern_path(dev_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path);
441 get_buffers(buffer, old_buffer);
442 error = fn_for_each_confined(label, profile,
443 match_mnt(profile, path, buffer, &old_path, old_buffer,
444 NULL, flags, NULL, false));
445 put_buffers(buffer, old_buffer);
451 int aa_mount_change_type(struct aa_label *label, const struct path *path,
454 struct aa_profile *profile;
461 /* These are the flags allowed by do_change_type() */
462 flags &= (MS_REC | MS_SILENT | MS_SHARED | MS_PRIVATE | MS_SLAVE |
466 error = fn_for_each_confined(label, profile,
467 match_mnt(profile, path, buffer, NULL, NULL, NULL,
468 flags, NULL, false));
474 int aa_move_mount(struct aa_label *label, const struct path *path,
475 const char *orig_name)
477 struct aa_profile *profile;
478 char *buffer = NULL, *old_buffer = NULL;
479 struct path old_path;
485 if (!orig_name || !*orig_name)
488 error = kern_path(orig_name, LOOKUP_FOLLOW, &old_path);
492 get_buffers(buffer, old_buffer);
493 error = fn_for_each_confined(label, profile,
494 match_mnt(profile, path, buffer, &old_path, old_buffer,
495 NULL, MS_MOVE, NULL, false));
496 put_buffers(buffer, old_buffer);
502 int aa_new_mount(struct aa_label *label, const char *dev_name,
503 const struct path *path, const char *type, unsigned long flags,
506 struct aa_profile *profile;
507 char *buffer = NULL, *dev_buffer = NULL;
510 int requires_dev = 0;
511 struct path tmp_path, *dev_path = NULL;
517 struct file_system_type *fstype;
519 fstype = get_fs_type(type);
522 binary = fstype->fs_flags & FS_BINARY_MOUNTDATA;
523 requires_dev = fstype->fs_flags & FS_REQUIRES_DEV;
524 put_filesystem(fstype);
527 if (!dev_name || !*dev_name)
530 error = kern_path(dev_name, LOOKUP_FOLLOW, &tmp_path);
533 dev_path = &tmp_path;
537 get_buffers(buffer, dev_buffer);
539 error = fn_for_each_confined(label, profile,
540 match_mnt(profile, path, buffer, dev_path, dev_buffer,
541 type, flags, data, binary));
543 error = fn_for_each_confined(label, profile,
544 match_mnt_path_str(profile, path, buffer, dev_name,
545 type, flags, data, binary, NULL));
547 put_buffers(buffer, dev_buffer);
554 static int profile_umount(struct aa_profile *profile, struct path *path,
557 struct aa_perms perms = { };
558 const char *name = NULL, *info = NULL;
565 if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
568 error = aa_path_name(path, path_flags(profile, path), buffer, &name,
569 &info, profile->disconnected);
573 state = aa_dfa_match(profile->policy.dfa,
574 profile->policy.start[AA_CLASS_MOUNT],
576 perms = compute_mnt_perms(profile->policy.dfa, state);
577 if (AA_MAY_UMOUNT & ~perms.allow)
581 return audit_mount(profile, OP_UMOUNT, name, NULL, NULL, NULL, 0, NULL,
582 AA_MAY_UMOUNT, &perms, info, error);
585 int aa_umount(struct aa_label *label, struct vfsmount *mnt, int flags)
587 struct aa_profile *profile;
590 struct path path = { .mnt = mnt, .dentry = mnt->mnt_root };
596 error = fn_for_each_confined(label, profile,
597 profile_umount(profile, &path, buffer));
603 /* helper fn for transition on pivotroot
605 * Returns: label for transition or ERR_PTR. Does not return NULL
607 static struct aa_label *build_pivotroot(struct aa_profile *profile,
608 const struct path *new_path,
610 const struct path *old_path,
613 const char *old_name, *new_name = NULL, *info = NULL;
614 const char *trans_name = NULL;
615 struct aa_perms perms = { };
623 if (profile_unconfined(profile) ||
624 !PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
625 return aa_get_newest_label(&profile->label);
627 error = aa_path_name(old_path, path_flags(profile, old_path),
628 old_buffer, &old_name, &info,
629 profile->disconnected);
632 error = aa_path_name(new_path, path_flags(profile, new_path),
633 new_buffer, &new_name, &info,
634 profile->disconnected);
639 state = aa_dfa_match(profile->policy.dfa,
640 profile->policy.start[AA_CLASS_MOUNT],
642 state = aa_dfa_null_transition(profile->policy.dfa, state);
643 state = aa_dfa_match(profile->policy.dfa, state, old_name);
644 perms = compute_mnt_perms(profile->policy.dfa, state);
646 if (AA_MAY_PIVOTROOT & perms.allow)
650 error = audit_mount(profile, OP_PIVOTROOT, new_name, old_name,
651 NULL, trans_name, 0, NULL, AA_MAY_PIVOTROOT,
652 &perms, info, error);
654 return ERR_PTR(error);
656 return aa_get_newest_label(&profile->label);
659 int aa_pivotroot(struct aa_label *label, const struct path *old_path,
660 const struct path *new_path)
662 struct aa_profile *profile;
663 struct aa_label *target = NULL;
664 char *old_buffer = NULL, *new_buffer = NULL, *info = NULL;
671 get_buffers(old_buffer, new_buffer);
672 target = fn_label_build(label, profile, GFP_ATOMIC,
673 build_pivotroot(profile, new_path, new_buffer,
674 old_path, old_buffer));
676 info = "label build failed";
679 } else if (!IS_ERR(target)) {
680 error = aa_replace_current_label(target);
682 /* TODO: audit target */
683 aa_put_label(target);
686 aa_put_label(target);
688 /* already audited error */
689 error = PTR_ERR(target);
691 put_buffers(old_buffer, new_buffer);
696 /* TODO: add back in auditing of new_name and old_name */
697 error = fn_for_each(label, profile,
698 audit_mount(profile, OP_PIVOTROOT, NULL /*new_name */,
701 0, NULL, AA_MAY_PIVOTROOT, &nullperms, info,