2 * AppArmor security module
4 * This file contains AppArmor mediation of files
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2017 Canonical Ltd.
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
16 #include <linux/mount.h>
17 #include <linux/namei.h>
19 #include "include/apparmor.h"
20 #include "include/audit.h"
21 #include "include/context.h"
22 #include "include/domain.h"
23 #include "include/file.h"
24 #include "include/match.h"
25 #include "include/mount.h"
26 #include "include/path.h"
27 #include "include/policy.h"
30 static void audit_mnt_flags(struct audit_buffer *ab, unsigned long flags)
32 if (flags & MS_RDONLY)
33 audit_log_format(ab, "ro");
35 audit_log_format(ab, "rw");
36 if (flags & MS_NOSUID)
37 audit_log_format(ab, ", nosuid");
39 audit_log_format(ab, ", nodev");
40 if (flags & MS_NOEXEC)
41 audit_log_format(ab, ", noexec");
42 if (flags & MS_SYNCHRONOUS)
43 audit_log_format(ab, ", sync");
44 if (flags & MS_REMOUNT)
45 audit_log_format(ab, ", remount");
46 if (flags & MS_MANDLOCK)
47 audit_log_format(ab, ", mand");
48 if (flags & MS_DIRSYNC)
49 audit_log_format(ab, ", dirsync");
50 if (flags & MS_NOATIME)
51 audit_log_format(ab, ", noatime");
52 if (flags & MS_NODIRATIME)
53 audit_log_format(ab, ", nodiratime");
55 audit_log_format(ab, flags & MS_REC ? ", rbind" : ", bind");
57 audit_log_format(ab, ", move");
58 if (flags & MS_SILENT)
59 audit_log_format(ab, ", silent");
60 if (flags & MS_POSIXACL)
61 audit_log_format(ab, ", acl");
62 if (flags & MS_UNBINDABLE)
63 audit_log_format(ab, flags & MS_REC ? ", runbindable" :
65 if (flags & MS_PRIVATE)
66 audit_log_format(ab, flags & MS_REC ? ", rprivate" :
69 audit_log_format(ab, flags & MS_REC ? ", rslave" :
71 if (flags & MS_SHARED)
72 audit_log_format(ab, flags & MS_REC ? ", rshared" :
74 if (flags & MS_RELATIME)
75 audit_log_format(ab, ", relatime");
76 if (flags & MS_I_VERSION)
77 audit_log_format(ab, ", iversion");
78 if (flags & MS_STRICTATIME)
79 audit_log_format(ab, ", strictatime");
80 if (flags & MS_NOUSER)
81 audit_log_format(ab, ", nouser");
85 * audit_cb - call back for mount specific audit fields
86 * @ab: audit_buffer (NOT NULL)
87 * @va: audit struct to audit values of (NOT NULL)
89 static void audit_cb(struct audit_buffer *ab, void *va)
91 struct common_audit_data *sa = va;
93 if (aad(sa)->mnt.type) {
94 audit_log_format(ab, " fstype=");
95 audit_log_untrustedstring(ab, aad(sa)->mnt.type);
97 if (aad(sa)->mnt.src_name) {
98 audit_log_format(ab, " srcname=");
99 audit_log_untrustedstring(ab, aad(sa)->mnt.src_name);
101 if (aad(sa)->mnt.trans) {
102 audit_log_format(ab, " trans=");
103 audit_log_untrustedstring(ab, aad(sa)->mnt.trans);
105 if (aad(sa)->mnt.flags) {
106 audit_log_format(ab, " flags=\"");
107 audit_mnt_flags(ab, aad(sa)->mnt.flags);
108 audit_log_format(ab, "\"");
110 if (aad(sa)->mnt.data) {
111 audit_log_format(ab, " options=");
112 audit_log_untrustedstring(ab, aad(sa)->mnt.data);
117 * audit_mount - handle the auditing of mount operations
118 * @profile: the profile being enforced (NOT NULL)
119 * @op: operation being mediated (NOT NULL)
120 * @name: name of object being mediated (MAYBE NULL)
121 * @src_name: src_name of object being mediated (MAYBE_NULL)
122 * @type: type of filesystem (MAYBE_NULL)
123 * @trans: name of trans (MAYBE NULL)
124 * @flags: filesystem idependent mount flags
125 * @data: filesystem mount flags
126 * @request: permissions requested
127 * @perms: the permissions computed for the request (NOT NULL)
128 * @info: extra information message (MAYBE NULL)
129 * @error: 0 if operation allowed else failure error code
131 * Returns: %0 or error on failure
133 static int audit_mount(struct aa_profile *profile, const char *op,
134 const char *name, const char *src_name,
135 const char *type, const char *trans,
136 unsigned long flags, const void *data, u32 request,
137 struct aa_perms *perms, const char *info, int error)
139 int audit_type = AUDIT_APPARMOR_AUTO;
140 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, op);
142 if (likely(!error)) {
143 u32 mask = perms->audit;
145 if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
148 /* mask off perms that are not being force audited */
151 if (likely(!request))
153 audit_type = AUDIT_APPARMOR_AUDIT;
155 /* only report permissions that were denied */
156 request = request & ~perms->allow;
158 if (request & perms->kill)
159 audit_type = AUDIT_APPARMOR_KILL;
161 /* quiet known rejects, assumes quiet and kill do not overlap */
162 if ((request & perms->quiet) &&
163 AUDIT_MODE(profile) != AUDIT_NOQUIET &&
164 AUDIT_MODE(profile) != AUDIT_ALL)
165 request &= ~perms->quiet;
171 aad(&sa)->name = name;
172 aad(&sa)->mnt.src_name = src_name;
173 aad(&sa)->mnt.type = type;
174 aad(&sa)->mnt.trans = trans;
175 aad(&sa)->mnt.flags = flags;
176 if (data && (perms->audit & AA_AUDIT_DATA))
177 aad(&sa)->mnt.data = data;
178 aad(&sa)->info = info;
179 aad(&sa)->error = error;
181 return aa_audit(audit_type, profile, &sa, audit_cb);
185 * match_mnt_flags - Do an ordered match on mount flags
186 * @dfa: dfa to match against
187 * @state: state to start in
188 * @flags: mount flags to match against
190 * Mount flags are encoded as an ordered match. This is done instead of
191 * checking against a simple bitmask, to allow for logical operations
194 * Returns: next state after flags match
196 static unsigned int match_mnt_flags(struct aa_dfa *dfa, unsigned int state,
201 for (i = 0; i <= 31 ; ++i) {
202 if ((1 << i) & flags)
203 state = aa_dfa_next(dfa, state, i + 1);
210 * compute_mnt_perms - compute mount permission associated with @state
211 * @dfa: dfa to match against (NOT NULL)
212 * @state: state match finished in
214 * Returns: mount permissions
216 static struct aa_perms compute_mnt_perms(struct aa_dfa *dfa,
219 struct aa_perms perms;
222 perms.allow = dfa_user_allow(dfa, state);
223 perms.audit = dfa_user_audit(dfa, state);
224 perms.quiet = dfa_user_quiet(dfa, state);
225 perms.xindex = dfa_user_xindex(dfa, state);
230 static const char * const mnt_info_table[] = {
232 "failed mntpnt match",
233 "failed srcname match",
235 "failed flags match",
241 * Returns 0 on success else element that match failed in, this is the
242 * index into the mnt_info_table above
244 static int do_match_mnt(struct aa_dfa *dfa, unsigned int start,
245 const char *mntpnt, const char *devname,
246 const char *type, unsigned long flags,
247 void *data, bool binary, struct aa_perms *perms)
254 state = aa_dfa_match(dfa, start, mntpnt);
255 state = aa_dfa_null_transition(dfa, state);
260 state = aa_dfa_match(dfa, state, devname);
261 state = aa_dfa_null_transition(dfa, state);
266 state = aa_dfa_match(dfa, state, type);
267 state = aa_dfa_null_transition(dfa, state);
271 state = match_mnt_flags(dfa, state, flags);
274 *perms = compute_mnt_perms(dfa, state);
275 if (perms->allow & AA_MAY_MOUNT)
278 /* only match data if not binary and the DFA flags data is expected */
279 if (data && !binary && (perms->allow & AA_MNT_CONT_MATCH)) {
280 state = aa_dfa_null_transition(dfa, state);
284 state = aa_dfa_match(dfa, state, data);
287 *perms = compute_mnt_perms(dfa, state);
288 if (perms->allow & AA_MAY_MOUNT)
292 /* failed at perms check, don't confuse with flags match */
297 static int path_flags(struct aa_profile *profile, const struct path *path)
302 return profile->path_flags |
303 (S_ISDIR(path->dentry->d_inode->i_mode) ? PATH_IS_DIR : 0);
307 * match_mnt_path_str - handle path matching for mount
308 * @profile: the confining profile
309 * @mntpath: for the mntpnt (NOT NULL)
310 * @buffer: buffer to be used to lookup mntpath
311 * @devnme: string for the devname/src_name (MAY BE NULL OR ERRPTR)
312 * @type: string for the dev type (MAYBE NULL)
313 * @flags: mount flags to match
314 * @data: fs mount data (MAYBE NULL)
315 * @binary: whether @data is binary
316 * @devinfo: error str if (IS_ERR(@devname))
318 * Returns: 0 on success else error
320 static int match_mnt_path_str(struct aa_profile *profile,
321 const struct path *mntpath, char *buffer,
322 const char *devname, const char *type,
323 unsigned long flags, void *data, bool binary,
326 struct aa_perms perms = { };
327 const char *mntpnt = NULL, *info = NULL;
334 if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
337 error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer,
338 &mntpnt, &info, profile->disconnected);
341 if (IS_ERR(devname)) {
342 error = PTR_ERR(devname);
349 pos = do_match_mnt(profile->policy.dfa,
350 profile->policy.start[AA_CLASS_MOUNT],
351 mntpnt, devname, type, flags, data, binary, &perms);
353 info = mnt_info_table[pos];
359 return audit_mount(profile, OP_MOUNT, mntpnt, devname, type, NULL,
360 flags, data, AA_MAY_MOUNT, &perms, info, error);
364 * match_mnt - handle path matching for mount
365 * @profile: the confining profile
366 * @mntpath: for the mntpnt (NOT NULL)
367 * @buffer: buffer to be used to lookup mntpath
368 * @devpath: path devname/src_name (MAYBE NULL)
369 * @devbuffer: buffer to be used to lookup devname/src_name
370 * @type: string for the dev type (MAYBE NULL)
371 * @flags: mount flags to match
372 * @data: fs mount data (MAYBE NULL)
373 * @binary: whether @data is binary
375 * Returns: 0 on success else error
377 static int match_mnt(struct aa_profile *profile, const struct path *path,
378 char *buffer, struct path *devpath, char *devbuffer,
379 const char *type, unsigned long flags, void *data,
382 const char *devname = NULL, *info = NULL;
386 AA_BUG(devpath && !devbuffer);
388 if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
392 error = aa_path_name(devpath, path_flags(profile, devpath),
393 devbuffer, &devname, &info,
394 profile->disconnected);
396 devname = ERR_PTR(error);
399 return match_mnt_path_str(profile, path, buffer, devname, type, flags,
403 int aa_remount(struct aa_label *label, const struct path *path,
404 unsigned long flags, void *data)
406 struct aa_profile *profile;
414 binary = path->dentry->d_sb->s_type->fs_flags & FS_BINARY_MOUNTDATA;
417 error = fn_for_each_confined(label, profile,
418 match_mnt(profile, path, buffer, NULL, NULL, NULL,
419 flags, data, binary));
425 int aa_bind_mount(struct aa_label *label, const struct path *path,
426 const char *dev_name, unsigned long flags)
428 struct aa_profile *profile;
429 char *buffer = NULL, *old_buffer = NULL;
430 struct path old_path;
436 if (!dev_name || !*dev_name)
439 flags &= MS_REC | MS_BIND;
441 error = kern_path(dev_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path);
445 get_buffers(buffer, old_buffer);
446 error = fn_for_each_confined(label, profile,
447 match_mnt(profile, path, buffer, &old_path, old_buffer,
448 NULL, flags, NULL, false));
449 put_buffers(buffer, old_buffer);
455 int aa_mount_change_type(struct aa_label *label, const struct path *path,
458 struct aa_profile *profile;
465 /* These are the flags allowed by do_change_type() */
466 flags &= (MS_REC | MS_SILENT | MS_SHARED | MS_PRIVATE | MS_SLAVE |
470 error = fn_for_each_confined(label, profile,
471 match_mnt(profile, path, buffer, NULL, NULL, NULL,
472 flags, NULL, false));
478 int aa_move_mount(struct aa_label *label, const struct path *path,
479 const char *orig_name)
481 struct aa_profile *profile;
482 char *buffer = NULL, *old_buffer = NULL;
483 struct path old_path;
489 if (!orig_name || !*orig_name)
492 error = kern_path(orig_name, LOOKUP_FOLLOW, &old_path);
496 get_buffers(buffer, old_buffer);
497 error = fn_for_each_confined(label, profile,
498 match_mnt(profile, path, buffer, &old_path, old_buffer,
499 NULL, MS_MOVE, NULL, false));
500 put_buffers(buffer, old_buffer);
506 int aa_new_mount(struct aa_label *label, const char *dev_name,
507 const struct path *path, const char *type, unsigned long flags,
510 struct aa_profile *profile;
511 char *buffer = NULL, *dev_buffer = NULL;
514 int requires_dev = 0;
515 struct path tmp_path, *dev_path = NULL;
521 struct file_system_type *fstype;
523 fstype = get_fs_type(type);
526 binary = fstype->fs_flags & FS_BINARY_MOUNTDATA;
527 requires_dev = fstype->fs_flags & FS_REQUIRES_DEV;
528 put_filesystem(fstype);
531 if (!dev_name || !*dev_name)
534 error = kern_path(dev_name, LOOKUP_FOLLOW, &tmp_path);
537 dev_path = &tmp_path;
541 get_buffers(buffer, dev_buffer);
543 error = fn_for_each_confined(label, profile,
544 match_mnt(profile, path, buffer, dev_path, dev_buffer,
545 type, flags, data, binary));
547 error = fn_for_each_confined(label, profile,
548 match_mnt_path_str(profile, path, buffer, dev_name,
549 type, flags, data, binary, NULL));
551 put_buffers(buffer, dev_buffer);
558 static int profile_umount(struct aa_profile *profile, struct path *path,
561 struct aa_perms perms = { };
562 const char *name = NULL, *info = NULL;
569 if (!PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
572 error = aa_path_name(path, path_flags(profile, path), buffer, &name,
573 &info, profile->disconnected);
577 state = aa_dfa_match(profile->policy.dfa,
578 profile->policy.start[AA_CLASS_MOUNT],
580 perms = compute_mnt_perms(profile->policy.dfa, state);
581 if (AA_MAY_UMOUNT & ~perms.allow)
585 return audit_mount(profile, OP_UMOUNT, name, NULL, NULL, NULL, 0, NULL,
586 AA_MAY_UMOUNT, &perms, info, error);
589 int aa_umount(struct aa_label *label, struct vfsmount *mnt, int flags)
591 struct aa_profile *profile;
594 struct path path = { .mnt = mnt, .dentry = mnt->mnt_root };
600 error = fn_for_each_confined(label, profile,
601 profile_umount(profile, &path, buffer));
607 /* helper fn for transition on pivotroot
609 * Returns: label for transition or ERR_PTR. Does not return NULL
611 static struct aa_label *build_pivotroot(struct aa_profile *profile,
612 const struct path *new_path,
614 const struct path *old_path,
617 const char *old_name, *new_name = NULL, *info = NULL;
618 const char *trans_name = NULL;
619 struct aa_perms perms = { };
627 if (profile_unconfined(profile) ||
628 !PROFILE_MEDIATES(profile, AA_CLASS_MOUNT))
629 return aa_get_newest_label(&profile->label);
631 error = aa_path_name(old_path, path_flags(profile, old_path),
632 old_buffer, &old_name, &info,
633 profile->disconnected);
636 error = aa_path_name(new_path, path_flags(profile, new_path),
637 new_buffer, &new_name, &info,
638 profile->disconnected);
643 state = aa_dfa_match(profile->policy.dfa,
644 profile->policy.start[AA_CLASS_MOUNT],
646 state = aa_dfa_null_transition(profile->policy.dfa, state);
647 state = aa_dfa_match(profile->policy.dfa, state, old_name);
648 perms = compute_mnt_perms(profile->policy.dfa, state);
650 if (AA_MAY_PIVOTROOT & perms.allow)
654 error = audit_mount(profile, OP_PIVOTROOT, new_name, old_name,
655 NULL, trans_name, 0, NULL, AA_MAY_PIVOTROOT,
656 &perms, info, error);
658 return ERR_PTR(error);
660 return aa_get_newest_label(&profile->label);
663 int aa_pivotroot(struct aa_label *label, const struct path *old_path,
664 const struct path *new_path)
666 struct aa_profile *profile;
667 struct aa_label *target = NULL;
668 char *old_buffer = NULL, *new_buffer = NULL, *info = NULL;
675 get_buffers(old_buffer, new_buffer);
676 target = fn_label_build(label, profile, GFP_ATOMIC,
677 build_pivotroot(profile, new_path, new_buffer,
678 old_path, old_buffer));
680 info = "label build failed";
683 } else if (!IS_ERR(target)) {
684 error = aa_replace_current_label(target);
686 /* TODO: audit target */
687 aa_put_label(target);
690 aa_put_label(target);
692 /* already audited error */
693 error = PTR_ERR(target);
695 put_buffers(old_buffer, new_buffer);
700 /* TODO: add back in auditing of new_name and old_name */
701 error = fn_for_each(label, profile,
702 audit_mount(profile, OP_PIVOTROOT, NULL /*new_name */,
705 0, NULL, AA_MAY_PIVOTROOT, &nullperms, info,