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Commit | Line | Data |
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2ea3ffb7 JJ |
1 | /* |
2 | * AppArmor security module | |
3 | * | |
4 | * This file contains AppArmor mediation of files | |
5 | * | |
6 | * Copyright (C) 1998-2008 Novell/SUSE | |
7 | * Copyright 2009-2017 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/fs.h> | |
16 | #include <linux/mount.h> | |
17 | #include <linux/namei.h> | |
18 | ||
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" | |
28 | ||
29 | ||
30 | static void audit_mnt_flags(struct audit_buffer *ab, unsigned long flags) | |
31 | { | |
32 | if (flags & MS_RDONLY) | |
33 | audit_log_format(ab, "ro"); | |
34 | else | |
35 | audit_log_format(ab, "rw"); | |
36 | if (flags & MS_NOSUID) | |
37 | audit_log_format(ab, ", nosuid"); | |
38 | if (flags & MS_NODEV) | |
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"); | |
54 | if (flags & MS_BIND) | |
55 | audit_log_format(ab, flags & MS_REC ? ", rbind" : ", bind"); | |
56 | if (flags & MS_MOVE) | |
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" : | |
64 | ", unbindable"); | |
65 | if (flags & MS_PRIVATE) | |
66 | audit_log_format(ab, flags & MS_REC ? ", rprivate" : | |
67 | ", private"); | |
68 | if (flags & MS_SLAVE) | |
69 | audit_log_format(ab, flags & MS_REC ? ", rslave" : | |
70 | ", slave"); | |
71 | if (flags & MS_SHARED) | |
72 | audit_log_format(ab, flags & MS_REC ? ", rshared" : | |
73 | ", shared"); | |
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"); | |
82 | } | |
83 | ||
84 | /** | |
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) | |
88 | */ | |
89 | static void audit_cb(struct audit_buffer *ab, void *va) | |
90 | { | |
91 | struct common_audit_data *sa = va; | |
92 | ||
93 | if (aad(sa)->mnt.type) { | |
94 | audit_log_format(ab, " fstype="); | |
95 | audit_log_untrustedstring(ab, aad(sa)->mnt.type); | |
96 | } | |
97 | if (aad(sa)->mnt.src_name) { | |
98 | audit_log_format(ab, " srcname="); | |
99 | audit_log_untrustedstring(ab, aad(sa)->mnt.src_name); | |
100 | } | |
101 | if (aad(sa)->mnt.trans) { | |
102 | audit_log_format(ab, " trans="); | |
103 | audit_log_untrustedstring(ab, aad(sa)->mnt.trans); | |
104 | } | |
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, "\""); | |
109 | } | |
110 | if (aad(sa)->mnt.data) { | |
111 | audit_log_format(ab, " options="); | |
112 | audit_log_untrustedstring(ab, aad(sa)->mnt.data); | |
113 | } | |
114 | } | |
115 | ||
116 | /** | |
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 | |
130 | * | |
131 | * Returns: %0 or error on failure | |
132 | */ | |
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) | |
138 | { | |
139 | int audit_type = AUDIT_APPARMOR_AUTO; | |
140 | DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, op); | |
141 | ||
142 | if (likely(!error)) { | |
143 | u32 mask = perms->audit; | |
144 | ||
145 | if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL)) | |
146 | mask = 0xffff; | |
147 | ||
148 | /* mask off perms that are not being force audited */ | |
149 | request &= mask; | |
150 | ||
151 | if (likely(!request)) | |
152 | return 0; | |
153 | audit_type = AUDIT_APPARMOR_AUDIT; | |
154 | } else { | |
155 | /* only report permissions that were denied */ | |
156 | request = request & ~perms->allow; | |
157 | ||
158 | if (request & perms->kill) | |
159 | audit_type = AUDIT_APPARMOR_KILL; | |
160 | ||
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; | |
166 | ||
167 | if (!request) | |
168 | return error; | |
169 | } | |
170 | ||
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; | |
180 | ||
181 | return aa_audit(audit_type, profile, &sa, audit_cb); | |
182 | } | |
183 | ||
184 | /** | |
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 | |
189 | * | |
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 | |
192 | * on the flags. | |
193 | * | |
194 | * Returns: next state after flags match | |
195 | */ | |
196 | static unsigned int match_mnt_flags(struct aa_dfa *dfa, unsigned int state, | |
197 | unsigned long flags) | |
198 | { | |
199 | unsigned int i; | |
200 | ||
201 | for (i = 0; i <= 31 ; ++i) { | |
202 | if ((1 << i) & flags) | |
203 | state = aa_dfa_next(dfa, state, i + 1); | |
204 | } | |
205 | ||
206 | return state; | |
207 | } | |
208 | ||
209 | /** | |
210 | * compute_mnt_perms - compute mount permission associated with @state | |
211 | * @dfa: dfa to match against (NOT NULL) | |
212 | * @state: state match finished in | |
213 | * | |
214 | * Returns: mount permissions | |
215 | */ | |
216 | static struct aa_perms compute_mnt_perms(struct aa_dfa *dfa, | |
217 | unsigned int state) | |
218 | { | |
7bba39ae AB |
219 | struct aa_perms perms = { |
220 | .allow = dfa_user_allow(dfa, state), | |
221 | .audit = dfa_user_audit(dfa, state), | |
222 | .quiet = dfa_user_quiet(dfa, state), | |
223 | .xindex = dfa_user_xindex(dfa, state), | |
224 | }; | |
2ea3ffb7 JJ |
225 | |
226 | return perms; | |
227 | } | |
228 | ||
229 | static const char * const mnt_info_table[] = { | |
230 | "match succeeded", | |
231 | "failed mntpnt match", | |
232 | "failed srcname match", | |
233 | "failed type match", | |
234 | "failed flags match", | |
235 | "failed data match" | |
236 | }; | |
237 | ||
238 | /* | |
239 | * Returns 0 on success else element that match failed in, this is the | |
240 | * index into the mnt_info_table above | |
241 | */ | |
242 | static int do_match_mnt(struct aa_dfa *dfa, unsigned int start, | |
243 | const char *mntpnt, const char *devname, | |
244 | const char *type, unsigned long flags, | |
245 | void *data, bool binary, struct aa_perms *perms) | |
246 | { | |
247 | unsigned int state; | |
248 | ||
249 | AA_BUG(!dfa); | |
250 | AA_BUG(!perms); | |
251 | ||
252 | state = aa_dfa_match(dfa, start, mntpnt); | |
253 | state = aa_dfa_null_transition(dfa, state); | |
254 | if (!state) | |
255 | return 1; | |
256 | ||
257 | if (devname) | |
258 | state = aa_dfa_match(dfa, state, devname); | |
259 | state = aa_dfa_null_transition(dfa, state); | |
260 | if (!state) | |
261 | return 2; | |
262 | ||
263 | if (type) | |
264 | state = aa_dfa_match(dfa, state, type); | |
265 | state = aa_dfa_null_transition(dfa, state); | |
266 | if (!state) | |
267 | return 3; | |
268 | ||
269 | state = match_mnt_flags(dfa, state, flags); | |
270 | if (!state) | |
271 | return 4; | |
272 | *perms = compute_mnt_perms(dfa, state); | |
273 | if (perms->allow & AA_MAY_MOUNT) | |
274 | return 0; | |
275 | ||
276 | /* only match data if not binary and the DFA flags data is expected */ | |
277 | if (data && !binary && (perms->allow & AA_MNT_CONT_MATCH)) { | |
278 | state = aa_dfa_null_transition(dfa, state); | |
279 | if (!state) | |
280 | return 4; | |
281 | ||
282 | state = aa_dfa_match(dfa, state, data); | |
283 | if (!state) | |
284 | return 5; | |
285 | *perms = compute_mnt_perms(dfa, state); | |
286 | if (perms->allow & AA_MAY_MOUNT) | |
287 | return 0; | |
288 | } | |
289 | ||
290 | /* failed at end of flags match */ | |
291 | return 4; | |
292 | } | |
293 | ||
294 | ||
295 | static int path_flags(struct aa_profile *profile, const struct path *path) | |
296 | { | |
297 | AA_BUG(!profile); | |
298 | AA_BUG(!path); | |
299 | ||
300 | return profile->path_flags | | |
301 | (S_ISDIR(path->dentry->d_inode->i_mode) ? PATH_IS_DIR : 0); | |
302 | } | |
303 | ||
304 | /** | |
305 | * match_mnt_path_str - handle path matching for mount | |
306 | * @profile: the confining profile | |
307 | * @mntpath: for the mntpnt (NOT NULL) | |
308 | * @buffer: buffer to be used to lookup mntpath | |
309 | * @devnme: string for the devname/src_name (MAY BE NULL OR ERRPTR) | |
310 | * @type: string for the dev type (MAYBE NULL) | |
311 | * @flags: mount flags to match | |
312 | * @data: fs mount data (MAYBE NULL) | |
313 | * @binary: whether @data is binary | |
314 | * @devinfo: error str if (IS_ERR(@devname)) | |
315 | * | |
316 | * Returns: 0 on success else error | |
317 | */ | |
318 | static int match_mnt_path_str(struct aa_profile *profile, | |
319 | const struct path *mntpath, char *buffer, | |
320 | const char *devname, const char *type, | |
321 | unsigned long flags, void *data, bool binary, | |
322 | const char *devinfo) | |
323 | { | |
324 | struct aa_perms perms = { }; | |
325 | const char *mntpnt = NULL, *info = NULL; | |
326 | int pos, error; | |
327 | ||
328 | AA_BUG(!profile); | |
329 | AA_BUG(!mntpath); | |
330 | AA_BUG(!buffer); | |
331 | ||
332 | error = aa_path_name(mntpath, path_flags(profile, mntpath), buffer, | |
333 | &mntpnt, &info, profile->disconnected); | |
334 | if (error) | |
335 | goto audit; | |
336 | if (IS_ERR(devname)) { | |
337 | error = PTR_ERR(devname); | |
338 | devname = NULL; | |
339 | info = devinfo; | |
340 | goto audit; | |
341 | } | |
342 | ||
343 | error = -EACCES; | |
344 | pos = do_match_mnt(profile->policy.dfa, | |
345 | profile->policy.start[AA_CLASS_MOUNT], | |
346 | mntpnt, devname, type, flags, data, binary, &perms); | |
347 | if (pos) { | |
348 | info = mnt_info_table[pos]; | |
349 | goto audit; | |
350 | } | |
351 | error = 0; | |
352 | ||
353 | audit: | |
354 | return audit_mount(profile, OP_MOUNT, mntpnt, devname, type, NULL, | |
355 | flags, data, AA_MAY_MOUNT, &perms, info, error); | |
356 | } | |
357 | ||
358 | /** | |
359 | * match_mnt - handle path matching for mount | |
360 | * @profile: the confining profile | |
361 | * @mntpath: for the mntpnt (NOT NULL) | |
362 | * @buffer: buffer to be used to lookup mntpath | |
363 | * @devpath: path devname/src_name (MAYBE NULL) | |
364 | * @devbuffer: buffer to be used to lookup devname/src_name | |
365 | * @type: string for the dev type (MAYBE NULL) | |
366 | * @flags: mount flags to match | |
367 | * @data: fs mount data (MAYBE NULL) | |
368 | * @binary: whether @data is binary | |
369 | * | |
370 | * Returns: 0 on success else error | |
371 | */ | |
372 | static int match_mnt(struct aa_profile *profile, const struct path *path, | |
373 | char *buffer, struct path *devpath, char *devbuffer, | |
374 | const char *type, unsigned long flags, void *data, | |
375 | bool binary) | |
376 | { | |
377 | const char *devname = NULL, *info = NULL; | |
378 | int error = -EACCES; | |
379 | ||
380 | AA_BUG(!profile); | |
381 | AA_BUG(devpath && !devbuffer); | |
382 | ||
383 | if (devpath) { | |
384 | error = aa_path_name(devpath, path_flags(profile, devpath), | |
385 | devbuffer, &devname, &info, | |
386 | profile->disconnected); | |
387 | if (error) | |
388 | devname = ERR_PTR(error); | |
389 | } | |
390 | ||
391 | return match_mnt_path_str(profile, path, buffer, devname, type, flags, | |
392 | data, binary, info); | |
393 | } | |
394 | ||
395 | int aa_remount(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 | get_buffers(buffer); | |
409 | error = fn_for_each_confined(label, profile, | |
410 | match_mnt(profile, path, buffer, NULL, NULL, NULL, | |
411 | flags, data, binary)); | |
412 | put_buffers(buffer); | |
413 | ||
414 | return error; | |
415 | } | |
416 | ||
417 | int aa_bind_mount(struct aa_label *label, const struct path *path, | |
418 | const char *dev_name, unsigned long flags) | |
419 | { | |
420 | struct aa_profile *profile; | |
421 | char *buffer = NULL, *old_buffer = NULL; | |
422 | struct path old_path; | |
423 | int error; | |
424 | ||
425 | AA_BUG(!label); | |
426 | AA_BUG(!path); | |
427 | ||
428 | if (!dev_name || !*dev_name) | |
429 | return -EINVAL; | |
430 | ||
431 | flags &= MS_REC | MS_BIND; | |
432 | ||
433 | error = kern_path(dev_name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &old_path); | |
434 | if (error) | |
435 | return error; | |
436 | ||
437 | get_buffers(buffer, old_buffer); | |
438 | error = fn_for_each_confined(label, profile, | |
439 | match_mnt(profile, path, buffer, &old_path, old_buffer, | |
440 | NULL, flags, NULL, false)); | |
441 | put_buffers(buffer, old_buffer); | |
442 | path_put(&old_path); | |
443 | ||
444 | return error; | |
445 | } | |
446 | ||
447 | int aa_mount_change_type(struct aa_label *label, const struct path *path, | |
448 | unsigned long flags) | |
449 | { | |
450 | struct aa_profile *profile; | |
451 | char *buffer = NULL; | |
452 | int error; | |
453 | ||
454 | AA_BUG(!label); | |
455 | AA_BUG(!path); | |
456 | ||
457 | /* These are the flags allowed by do_change_type() */ | |
458 | flags &= (MS_REC | MS_SILENT | MS_SHARED | MS_PRIVATE | MS_SLAVE | | |
459 | MS_UNBINDABLE); | |
460 | ||
461 | get_buffers(buffer); | |
462 | error = fn_for_each_confined(label, profile, | |
463 | match_mnt(profile, path, buffer, NULL, NULL, NULL, | |
464 | flags, NULL, false)); | |
465 | put_buffers(buffer); | |
466 | ||
467 | return error; | |
468 | } | |
469 | ||
470 | int aa_move_mount(struct aa_label *label, const struct path *path, | |
471 | const char *orig_name) | |
472 | { | |
473 | struct aa_profile *profile; | |
474 | char *buffer = NULL, *old_buffer = NULL; | |
475 | struct path old_path; | |
476 | int error; | |
477 | ||
478 | AA_BUG(!label); | |
479 | AA_BUG(!path); | |
480 | ||
481 | if (!orig_name || !*orig_name) | |
482 | return -EINVAL; | |
483 | ||
484 | error = kern_path(orig_name, LOOKUP_FOLLOW, &old_path); | |
485 | if (error) | |
486 | return error; | |
487 | ||
488 | get_buffers(buffer, old_buffer); | |
489 | error = fn_for_each_confined(label, profile, | |
490 | match_mnt(profile, path, buffer, &old_path, old_buffer, | |
491 | NULL, MS_MOVE, NULL, false)); | |
492 | put_buffers(buffer, old_buffer); | |
493 | path_put(&old_path); | |
494 | ||
495 | return error; | |
496 | } | |
497 | ||
498 | int aa_new_mount(struct aa_label *label, const char *dev_name, | |
499 | const struct path *path, const char *type, unsigned long flags, | |
500 | void *data) | |
501 | { | |
502 | struct aa_profile *profile; | |
503 | char *buffer = NULL, *dev_buffer = NULL; | |
504 | bool binary = true; | |
505 | int error; | |
506 | int requires_dev = 0; | |
507 | struct path tmp_path, *dev_path = NULL; | |
508 | ||
509 | AA_BUG(!label); | |
510 | AA_BUG(!path); | |
511 | ||
512 | if (type) { | |
513 | struct file_system_type *fstype; | |
514 | ||
515 | fstype = get_fs_type(type); | |
516 | if (!fstype) | |
517 | return -ENODEV; | |
518 | binary = fstype->fs_flags & FS_BINARY_MOUNTDATA; | |
519 | requires_dev = fstype->fs_flags & FS_REQUIRES_DEV; | |
520 | put_filesystem(fstype); | |
521 | ||
522 | if (requires_dev) { | |
523 | if (!dev_name || !*dev_name) | |
524 | return -ENOENT; | |
525 | ||
526 | error = kern_path(dev_name, LOOKUP_FOLLOW, &tmp_path); | |
527 | if (error) | |
528 | return error; | |
529 | dev_path = &tmp_path; | |
530 | } | |
531 | } | |
532 | ||
533 | get_buffers(buffer, dev_buffer); | |
534 | if (dev_path) { | |
535 | error = fn_for_each_confined(label, profile, | |
536 | match_mnt(profile, path, buffer, dev_path, dev_buffer, | |
537 | type, flags, data, binary)); | |
538 | } else { | |
539 | error = fn_for_each_confined(label, profile, | |
540 | match_mnt_path_str(profile, path, buffer, dev_name, | |
541 | type, flags, data, binary, NULL)); | |
542 | } | |
543 | put_buffers(buffer, dev_buffer); | |
544 | if (dev_path) | |
545 | path_put(dev_path); | |
546 | ||
547 | return error; | |
548 | } | |
549 | ||
550 | static int profile_umount(struct aa_profile *profile, struct path *path, | |
551 | char *buffer) | |
552 | { | |
553 | struct aa_perms perms = { }; | |
554 | const char *name = NULL, *info = NULL; | |
555 | unsigned int state; | |
556 | int error; | |
557 | ||
558 | AA_BUG(!profile); | |
559 | AA_BUG(!path); | |
560 | ||
561 | error = aa_path_name(path, path_flags(profile, path), buffer, &name, | |
562 | &info, profile->disconnected); | |
563 | if (error) | |
564 | goto audit; | |
565 | ||
566 | state = aa_dfa_match(profile->policy.dfa, | |
567 | profile->policy.start[AA_CLASS_MOUNT], | |
568 | name); | |
569 | perms = compute_mnt_perms(profile->policy.dfa, state); | |
570 | if (AA_MAY_UMOUNT & ~perms.allow) | |
571 | error = -EACCES; | |
572 | ||
573 | audit: | |
574 | return audit_mount(profile, OP_UMOUNT, name, NULL, NULL, NULL, 0, NULL, | |
575 | AA_MAY_UMOUNT, &perms, info, error); | |
576 | } | |
577 | ||
578 | int aa_umount(struct aa_label *label, struct vfsmount *mnt, int flags) | |
579 | { | |
580 | struct aa_profile *profile; | |
581 | char *buffer = NULL; | |
582 | int error; | |
583 | struct path path = { .mnt = mnt, .dentry = mnt->mnt_root }; | |
584 | ||
585 | AA_BUG(!label); | |
586 | AA_BUG(!mnt); | |
587 | ||
588 | get_buffers(buffer); | |
589 | error = fn_for_each_confined(label, profile, | |
590 | profile_umount(profile, &path, buffer)); | |
591 | put_buffers(buffer); | |
592 | ||
593 | return error; | |
594 | } | |
595 | ||
596 | /* helper fn for transition on pivotroot | |
597 | * | |
598 | * Returns: label for transition or ERR_PTR. Does not return NULL | |
599 | */ | |
600 | static struct aa_label *build_pivotroot(struct aa_profile *profile, | |
601 | const struct path *new_path, | |
602 | char *new_buffer, | |
603 | const struct path *old_path, | |
604 | char *old_buffer) | |
605 | { | |
606 | const char *old_name, *new_name = NULL, *info = NULL; | |
607 | const char *trans_name = NULL; | |
608 | struct aa_perms perms = { }; | |
609 | unsigned int state; | |
610 | int error; | |
611 | ||
612 | AA_BUG(!profile); | |
613 | AA_BUG(!new_path); | |
614 | AA_BUG(!old_path); | |
615 | ||
616 | if (profile_unconfined(profile)) | |
617 | return aa_get_newest_label(&profile->label); | |
618 | ||
619 | error = aa_path_name(old_path, path_flags(profile, old_path), | |
620 | old_buffer, &old_name, &info, | |
621 | profile->disconnected); | |
622 | if (error) | |
623 | goto audit; | |
624 | error = aa_path_name(new_path, path_flags(profile, new_path), | |
625 | new_buffer, &new_name, &info, | |
626 | profile->disconnected); | |
627 | if (error) | |
628 | goto audit; | |
629 | ||
630 | error = -EACCES; | |
631 | state = aa_dfa_match(profile->policy.dfa, | |
632 | profile->policy.start[AA_CLASS_MOUNT], | |
633 | new_name); | |
634 | state = aa_dfa_null_transition(profile->policy.dfa, state); | |
635 | state = aa_dfa_match(profile->policy.dfa, state, old_name); | |
636 | perms = compute_mnt_perms(profile->policy.dfa, state); | |
637 | ||
638 | if (AA_MAY_PIVOTROOT & perms.allow) | |
639 | error = 0; | |
640 | ||
641 | audit: | |
642 | error = audit_mount(profile, OP_PIVOTROOT, new_name, old_name, | |
643 | NULL, trans_name, 0, NULL, AA_MAY_PIVOTROOT, | |
644 | &perms, info, error); | |
645 | if (error) | |
646 | return ERR_PTR(error); | |
647 | ||
648 | return aa_get_newest_label(&profile->label); | |
649 | } | |
650 | ||
651 | int aa_pivotroot(struct aa_label *label, const struct path *old_path, | |
652 | const struct path *new_path) | |
653 | { | |
654 | struct aa_profile *profile; | |
655 | struct aa_label *target = NULL; | |
656 | char *old_buffer = NULL, *new_buffer = NULL, *info = NULL; | |
657 | int error; | |
658 | ||
659 | AA_BUG(!label); | |
660 | AA_BUG(!old_path); | |
661 | AA_BUG(!new_path); | |
662 | ||
663 | get_buffers(old_buffer, new_buffer); | |
664 | target = fn_label_build(label, profile, GFP_ATOMIC, | |
665 | build_pivotroot(profile, new_path, new_buffer, | |
666 | old_path, old_buffer)); | |
667 | if (!target) { | |
668 | info = "label build failed"; | |
669 | error = -ENOMEM; | |
670 | goto fail; | |
671 | } else if (!IS_ERR(target)) { | |
672 | error = aa_replace_current_label(target); | |
673 | if (error) { | |
674 | /* TODO: audit target */ | |
675 | aa_put_label(target); | |
676 | goto out; | |
677 | } | |
678 | } else | |
679 | /* already audited error */ | |
680 | error = PTR_ERR(target); | |
681 | out: | |
682 | put_buffers(old_buffer, new_buffer); | |
683 | ||
684 | return error; | |
685 | ||
686 | fail: | |
687 | /* TODO: add back in auditing of new_name and old_name */ | |
688 | error = fn_for_each(label, profile, | |
689 | audit_mount(profile, OP_PIVOTROOT, NULL /*new_name */, | |
690 | NULL /* old_name */, | |
691 | NULL, NULL, | |
692 | 0, NULL, AA_MAY_PIVOTROOT, &nullperms, info, | |
693 | error)); | |
694 | goto out; | |
695 | } |