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Commit | Line | Data |
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6380bd8d 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 2009-2010 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 | ||
192ca6b5 JJ |
15 | #include <linux/tty.h> |
16 | #include <linux/fdtable.h> | |
17 | #include <linux/file.h> | |
18 | ||
6380bd8d JJ |
19 | #include "include/apparmor.h" |
20 | #include "include/audit.h" | |
192ca6b5 | 21 | #include "include/context.h" |
6380bd8d JJ |
22 | #include "include/file.h" |
23 | #include "include/match.h" | |
695b0eb9 | 24 | #include "include/net.h" |
6380bd8d JJ |
25 | #include "include/path.h" |
26 | #include "include/policy.h" | |
190a9518 | 27 | #include "include/label.h" |
6380bd8d | 28 | |
e53cfe6c JJ |
29 | static u32 map_mask_to_chr_mask(u32 mask) |
30 | { | |
31 | u32 m = mask & PERMS_CHRS_MASK; | |
32 | ||
33 | if (mask & AA_MAY_GETATTR) | |
34 | m |= MAY_READ; | |
35 | if (mask & (AA_MAY_SETATTR | AA_MAY_CHMOD | AA_MAY_CHOWN)) | |
36 | m |= MAY_WRITE; | |
37 | ||
38 | return m; | |
39 | } | |
6380bd8d JJ |
40 | |
41 | /** | |
42 | * audit_file_mask - convert mask to permission string | |
43 | * @buffer: buffer to write string to (NOT NULL) | |
44 | * @mask: permission mask to convert | |
45 | */ | |
46 | static void audit_file_mask(struct audit_buffer *ab, u32 mask) | |
47 | { | |
48 | char str[10]; | |
49 | ||
e53cfe6c | 50 | aa_perm_mask_to_str(str, aa_file_perm_chrs, map_mask_to_chr_mask(mask)); |
6380bd8d JJ |
51 | audit_log_string(ab, str); |
52 | } | |
53 | ||
54 | /** | |
55 | * file_audit_cb - call back for file specific audit fields | |
56 | * @ab: audit_buffer (NOT NULL) | |
57 | * @va: audit struct to audit values of (NOT NULL) | |
58 | */ | |
59 | static void file_audit_cb(struct audit_buffer *ab, void *va) | |
60 | { | |
61 | struct common_audit_data *sa = va; | |
2db81452 | 62 | kuid_t fsuid = current_fsuid(); |
6380bd8d | 63 | |
aa9aeea8 | 64 | if (aad(sa)->request & AA_AUDIT_FILE_MASK) { |
6380bd8d | 65 | audit_log_format(ab, " requested_mask="); |
aa9aeea8 | 66 | audit_file_mask(ab, aad(sa)->request); |
6380bd8d | 67 | } |
aa9aeea8 | 68 | if (aad(sa)->denied & AA_AUDIT_FILE_MASK) { |
6380bd8d | 69 | audit_log_format(ab, " denied_mask="); |
aa9aeea8 | 70 | audit_file_mask(ab, aad(sa)->denied); |
6380bd8d | 71 | } |
aa9aeea8 | 72 | if (aad(sa)->request & AA_AUDIT_FILE_MASK) { |
2db81452 EB |
73 | audit_log_format(ab, " fsuid=%d", |
74 | from_kuid(&init_user_ns, fsuid)); | |
75 | audit_log_format(ab, " ouid=%d", | |
ef88a7ac | 76 | from_kuid(&init_user_ns, aad(sa)->fs.ouid)); |
6380bd8d JJ |
77 | } |
78 | ||
98c3d182 JJ |
79 | if (aad(sa)->peer) { |
80 | audit_log_format(ab, " target="); | |
81 | aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer, | |
82 | FLAG_VIEW_SUBNS, GFP_ATOMIC); | |
83 | } else if (aad(sa)->fs.target) { | |
6380bd8d | 84 | audit_log_format(ab, " target="); |
ef88a7ac | 85 | audit_log_untrustedstring(ab, aad(sa)->fs.target); |
6380bd8d JJ |
86 | } |
87 | } | |
88 | ||
89 | /** | |
90 | * aa_audit_file - handle the auditing of file operations | |
91 | * @profile: the profile being enforced (NOT NULL) | |
92 | * @perms: the permissions computed for the request (NOT NULL) | |
6380bd8d JJ |
93 | * @op: operation being mediated |
94 | * @request: permissions requested | |
95 | * @name: name of object being mediated (MAYBE NULL) | |
96 | * @target: name of target (MAYBE NULL) | |
98c3d182 | 97 | * @tlabel: target label (MAY BE NULL) |
6380bd8d JJ |
98 | * @ouid: object uid |
99 | * @info: extra information message (MAYBE NULL) | |
100 | * @error: 0 if operation allowed else failure error code | |
101 | * | |
102 | * Returns: %0 or error on failure | |
103 | */ | |
2d679f3c | 104 | int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms, |
ef88a7ac | 105 | const char *op, u32 request, const char *name, |
98c3d182 JJ |
106 | const char *target, struct aa_label *tlabel, |
107 | kuid_t ouid, const char *info, int error) | |
6380bd8d JJ |
108 | { |
109 | int type = AUDIT_APPARMOR_AUTO; | |
ef88a7ac JJ |
110 | DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_TASK, op); |
111 | ||
112 | sa.u.tsk = NULL; | |
aa9aeea8 | 113 | aad(&sa)->request = request; |
ef88a7ac JJ |
114 | aad(&sa)->name = name; |
115 | aad(&sa)->fs.target = target; | |
98c3d182 | 116 | aad(&sa)->peer = tlabel; |
ef88a7ac JJ |
117 | aad(&sa)->fs.ouid = ouid; |
118 | aad(&sa)->info = info; | |
119 | aad(&sa)->error = error; | |
b6b1b81b | 120 | sa.u.tsk = NULL; |
ef88a7ac JJ |
121 | |
122 | if (likely(!aad(&sa)->error)) { | |
6380bd8d JJ |
123 | u32 mask = perms->audit; |
124 | ||
125 | if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL)) | |
126 | mask = 0xffff; | |
127 | ||
128 | /* mask off perms that are not being force audited */ | |
aa9aeea8 | 129 | aad(&sa)->request &= mask; |
6380bd8d | 130 | |
aa9aeea8 | 131 | if (likely(!aad(&sa)->request)) |
6380bd8d JJ |
132 | return 0; |
133 | type = AUDIT_APPARMOR_AUDIT; | |
134 | } else { | |
135 | /* only report permissions that were denied */ | |
aa9aeea8 JJ |
136 | aad(&sa)->request = aad(&sa)->request & ~perms->allow; |
137 | AA_BUG(!aad(&sa)->request); | |
6380bd8d | 138 | |
aa9aeea8 | 139 | if (aad(&sa)->request & perms->kill) |
6380bd8d JJ |
140 | type = AUDIT_APPARMOR_KILL; |
141 | ||
142 | /* quiet known rejects, assumes quiet and kill do not overlap */ | |
aa9aeea8 | 143 | if ((aad(&sa)->request & perms->quiet) && |
6380bd8d JJ |
144 | AUDIT_MODE(profile) != AUDIT_NOQUIET && |
145 | AUDIT_MODE(profile) != AUDIT_ALL) | |
aa9aeea8 | 146 | aad(&sa)->request &= ~perms->quiet; |
6380bd8d | 147 | |
aa9aeea8 | 148 | if (!aad(&sa)->request) |
98c3d182 | 149 | return aad(&sa)->error; |
6380bd8d JJ |
150 | } |
151 | ||
aa9aeea8 | 152 | aad(&sa)->denied = aad(&sa)->request & ~perms->allow; |
ef88a7ac | 153 | return aa_audit(type, profile, &sa, file_audit_cb); |
6380bd8d JJ |
154 | } |
155 | ||
aebd873e JJ |
156 | /** |
157 | * is_deleted - test if a file has been completely unlinked | |
158 | * @dentry: dentry of file to test for deletion (NOT NULL) | |
159 | * | |
160 | * Returns: %1 if deleted else %0 | |
161 | */ | |
162 | static inline bool is_deleted(struct dentry *dentry) | |
163 | { | |
164 | if (d_unlinked(dentry) && d_backing_inode(dentry)->i_nlink == 0) | |
165 | return 1; | |
166 | return 0; | |
167 | } | |
168 | ||
169 | static int path_name(const char *op, struct aa_label *label, | |
170 | const struct path *path, int flags, char *buffer, | |
171 | const char **name, struct path_cond *cond, u32 request) | |
172 | { | |
173 | struct aa_profile *profile; | |
174 | const char *info = NULL; | |
175 | int error; | |
176 | ||
177 | error = aa_path_name(path, flags, buffer, name, &info, | |
178 | labels_profile(label)->disconnected); | |
179 | if (error) { | |
180 | fn_for_each_confined(label, profile, | |
181 | aa_audit_file(profile, &nullperms, op, request, *name, | |
182 | NULL, NULL, cond->uid, info, error)); | |
183 | return error; | |
184 | } | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
6380bd8d JJ |
189 | /** |
190 | * map_old_perms - map old file perms layout to the new layout | |
191 | * @old: permission set in old mapping | |
192 | * | |
193 | * Returns: new permission mapping | |
194 | */ | |
195 | static u32 map_old_perms(u32 old) | |
196 | { | |
197 | u32 new = old & 0xf; | |
198 | if (old & MAY_READ) | |
e53cfe6c | 199 | new |= AA_MAY_GETATTR | AA_MAY_OPEN; |
6380bd8d | 200 | if (old & MAY_WRITE) |
e53cfe6c JJ |
201 | new |= AA_MAY_SETATTR | AA_MAY_CREATE | AA_MAY_DELETE | |
202 | AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_OPEN; | |
6380bd8d JJ |
203 | if (old & 0x10) |
204 | new |= AA_MAY_LINK; | |
205 | /* the old mapping lock and link_subset flags where overlaid | |
206 | * and use was determined by part of a pair that they were in | |
207 | */ | |
208 | if (old & 0x20) | |
209 | new |= AA_MAY_LOCK | AA_LINK_SUBSET; | |
210 | if (old & 0x40) /* AA_EXEC_MMAP */ | |
211 | new |= AA_EXEC_MMAP; | |
212 | ||
6380bd8d JJ |
213 | return new; |
214 | } | |
215 | ||
216 | /** | |
2d679f3c | 217 | * aa_compute_fperms - convert dfa compressed perms to internal perms |
6380bd8d JJ |
218 | * @dfa: dfa to compute perms for (NOT NULL) |
219 | * @state: state in dfa | |
220 | * @cond: conditions to consider (NOT NULL) | |
221 | * | |
222 | * TODO: convert from dfa + state to permission entry, do computation conversion | |
223 | * at load time. | |
224 | * | |
225 | * Returns: computed permission set | |
226 | */ | |
2d679f3c JJ |
227 | struct aa_perms aa_compute_fperms(struct aa_dfa *dfa, unsigned int state, |
228 | struct path_cond *cond) | |
6380bd8d | 229 | { |
2d679f3c | 230 | struct aa_perms perms; |
6380bd8d JJ |
231 | |
232 | /* FIXME: change over to new dfa format | |
233 | * currently file perms are encoded in the dfa, new format | |
234 | * splits the permissions from the dfa. This mapping can be | |
235 | * done at profile load | |
236 | */ | |
2d679f3c JJ |
237 | perms.deny = 0; |
238 | perms.kill = perms.stop = 0; | |
239 | perms.complain = perms.cond = 0; | |
240 | perms.hide = 0; | |
241 | perms.prompt = 0; | |
6380bd8d | 242 | |
2db81452 | 243 | if (uid_eq(current_fsuid(), cond->uid)) { |
6380bd8d JJ |
244 | perms.allow = map_old_perms(dfa_user_allow(dfa, state)); |
245 | perms.audit = map_old_perms(dfa_user_audit(dfa, state)); | |
246 | perms.quiet = map_old_perms(dfa_user_quiet(dfa, state)); | |
247 | perms.xindex = dfa_user_xindex(dfa, state); | |
248 | } else { | |
249 | perms.allow = map_old_perms(dfa_other_allow(dfa, state)); | |
250 | perms.audit = map_old_perms(dfa_other_audit(dfa, state)); | |
251 | perms.quiet = map_old_perms(dfa_other_quiet(dfa, state)); | |
252 | perms.xindex = dfa_other_xindex(dfa, state); | |
253 | } | |
e53cfe6c | 254 | perms.allow |= AA_MAY_GETATTR; |
6380bd8d JJ |
255 | |
256 | /* change_profile wasn't determined by ownership in old mapping */ | |
257 | if (ACCEPT_TABLE(dfa)[state] & 0x80000000) | |
258 | perms.allow |= AA_MAY_CHANGE_PROFILE; | |
0421ea91 JJ |
259 | if (ACCEPT_TABLE(dfa)[state] & 0x40000000) |
260 | perms.allow |= AA_MAY_ONEXEC; | |
6380bd8d JJ |
261 | |
262 | return perms; | |
263 | } | |
264 | ||
265 | /** | |
266 | * aa_str_perms - find permission that match @name | |
267 | * @dfa: to match against (MAYBE NULL) | |
268 | * @state: state to start matching in | |
269 | * @name: string to match against dfa (NOT NULL) | |
270 | * @cond: conditions to consider for permission set computation (NOT NULL) | |
271 | * @perms: Returns - the permissions found when matching @name | |
272 | * | |
273 | * Returns: the final state in @dfa when beginning @start and walking @name | |
274 | */ | |
275 | unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start, | |
276 | const char *name, struct path_cond *cond, | |
2d679f3c | 277 | struct aa_perms *perms) |
6380bd8d JJ |
278 | { |
279 | unsigned int state; | |
6380bd8d | 280 | state = aa_dfa_match(dfa, start, name); |
2d679f3c | 281 | *perms = aa_compute_fperms(dfa, state, cond); |
6380bd8d JJ |
282 | |
283 | return state; | |
284 | } | |
285 | ||
aebd873e JJ |
286 | int __aa_path_perm(const char *op, struct aa_profile *profile, const char *name, |
287 | u32 request, struct path_cond *cond, int flags, | |
288 | struct aa_perms *perms) | |
6380bd8d | 289 | { |
aebd873e JJ |
290 | int e = 0; |
291 | ||
292 | if (profile_unconfined(profile)) | |
293 | return 0; | |
294 | aa_str_perms(profile->file.dfa, profile->file.start, name, cond, perms); | |
295 | if (request & ~perms->allow) | |
296 | e = -EACCES; | |
297 | return aa_audit_file(profile, perms, op, request, name, NULL, NULL, | |
298 | cond->uid, NULL, e); | |
299 | } | |
300 | ||
301 | ||
302 | static int profile_path_perm(const char *op, struct aa_profile *profile, | |
303 | const struct path *path, char *buffer, u32 request, | |
304 | struct path_cond *cond, int flags, | |
305 | struct aa_perms *perms) | |
306 | { | |
307 | const char *name; | |
308 | int error; | |
309 | ||
310 | if (profile_unconfined(profile)) | |
311 | return 0; | |
312 | ||
313 | error = path_name(op, &profile->label, path, | |
314 | flags | profile->path_flags, buffer, &name, cond, | |
315 | request); | |
316 | if (error) | |
317 | return error; | |
318 | return __aa_path_perm(op, profile, name, request, cond, flags, | |
319 | perms); | |
6380bd8d JJ |
320 | } |
321 | ||
322 | /** | |
323 | * aa_path_perm - do permissions check & audit for @path | |
324 | * @op: operation being checked | |
aebd873e | 325 | * @label: profile being enforced (NOT NULL) |
6380bd8d JJ |
326 | * @path: path to check permissions of (NOT NULL) |
327 | * @flags: any additional path flags beyond what the profile specifies | |
328 | * @request: requested permissions | |
329 | * @cond: conditional info for this request (NOT NULL) | |
330 | * | |
331 | * Returns: %0 else error if access denied or other error | |
332 | */ | |
aebd873e | 333 | int aa_path_perm(const char *op, struct aa_label *label, |
47f6e5cc JJ |
334 | const struct path *path, int flags, u32 request, |
335 | struct path_cond *cond) | |
6380bd8d | 336 | { |
2d679f3c | 337 | struct aa_perms perms = {}; |
aebd873e JJ |
338 | struct aa_profile *profile; |
339 | char *buffer = NULL; | |
6380bd8d JJ |
340 | int error; |
341 | ||
aebd873e JJ |
342 | flags |= PATH_DELEGATE_DELETED | (S_ISDIR(cond->mode) ? PATH_IS_DIR : |
343 | 0); | |
4227c333 | 344 | get_buffers(buffer); |
aebd873e JJ |
345 | error = fn_for_each_confined(label, profile, |
346 | profile_path_perm(op, profile, path, buffer, request, | |
347 | cond, flags, &perms)); | |
348 | ||
4227c333 | 349 | put_buffers(buffer); |
6380bd8d JJ |
350 | |
351 | return error; | |
352 | } | |
353 | ||
354 | /** | |
355 | * xindex_is_subset - helper for aa_path_link | |
356 | * @link: link permission set | |
357 | * @target: target permission set | |
358 | * | |
359 | * test target x permissions are equal OR a subset of link x permissions | |
360 | * this is done as part of the subset test, where a hardlink must have | |
361 | * a subset of permissions that the target has. | |
362 | * | |
363 | * Returns: %1 if subset else %0 | |
364 | */ | |
365 | static inline bool xindex_is_subset(u32 link, u32 target) | |
366 | { | |
367 | if (((link & ~AA_X_UNSAFE) != (target & ~AA_X_UNSAFE)) || | |
368 | ((link & AA_X_UNSAFE) && !(target & AA_X_UNSAFE))) | |
369 | return 0; | |
370 | ||
371 | return 1; | |
372 | } | |
373 | ||
8014370f JJ |
374 | static int profile_path_link(struct aa_profile *profile, |
375 | const struct path *link, char *buffer, | |
376 | const struct path *target, char *buffer2, | |
377 | struct path_cond *cond) | |
6380bd8d | 378 | { |
8014370f JJ |
379 | const char *lname, *tname = NULL; |
380 | struct aa_perms lperms = {}, perms; | |
381 | const char *info = NULL; | |
6380bd8d JJ |
382 | u32 request = AA_MAY_LINK; |
383 | unsigned int state; | |
384 | int error; | |
385 | ||
8014370f JJ |
386 | error = path_name(OP_LINK, &profile->label, link, profile->path_flags, |
387 | buffer, &lname, cond, AA_MAY_LINK); | |
6380bd8d JJ |
388 | if (error) |
389 | goto audit; | |
390 | ||
391 | /* buffer2 freed below, tname is pointer in buffer2 */ | |
8014370f JJ |
392 | error = path_name(OP_LINK, &profile->label, target, profile->path_flags, |
393 | buffer2, &tname, cond, AA_MAY_LINK); | |
6380bd8d JJ |
394 | if (error) |
395 | goto audit; | |
396 | ||
397 | error = -EACCES; | |
398 | /* aa_str_perms - handles the case of the dfa being NULL */ | |
399 | state = aa_str_perms(profile->file.dfa, profile->file.start, lname, | |
8014370f | 400 | cond, &lperms); |
6380bd8d JJ |
401 | |
402 | if (!(lperms.allow & AA_MAY_LINK)) | |
403 | goto audit; | |
404 | ||
405 | /* test to see if target can be paired with link */ | |
406 | state = aa_dfa_null_transition(profile->file.dfa, state); | |
8014370f | 407 | aa_str_perms(profile->file.dfa, state, tname, cond, &perms); |
6380bd8d JJ |
408 | |
409 | /* force audit/quiet masks for link are stored in the second entry | |
410 | * in the link pair. | |
411 | */ | |
412 | lperms.audit = perms.audit; | |
413 | lperms.quiet = perms.quiet; | |
414 | lperms.kill = perms.kill; | |
415 | ||
416 | if (!(perms.allow & AA_MAY_LINK)) { | |
417 | info = "target restricted"; | |
8014370f | 418 | lperms = perms; |
6380bd8d JJ |
419 | goto audit; |
420 | } | |
421 | ||
422 | /* done if link subset test is not required */ | |
423 | if (!(perms.allow & AA_LINK_SUBSET)) | |
424 | goto done_tests; | |
425 | ||
8014370f JJ |
426 | /* Do link perm subset test requiring allowed permission on link are |
427 | * a subset of the allowed permissions on target. | |
6380bd8d | 428 | */ |
8014370f | 429 | aa_str_perms(profile->file.dfa, profile->file.start, tname, cond, |
6380bd8d JJ |
430 | &perms); |
431 | ||
432 | /* AA_MAY_LINK is not considered in the subset test */ | |
433 | request = lperms.allow & ~AA_MAY_LINK; | |
434 | lperms.allow &= perms.allow | AA_MAY_LINK; | |
435 | ||
436 | request |= AA_AUDIT_FILE_MASK & (lperms.allow & ~perms.allow); | |
437 | if (request & ~lperms.allow) { | |
438 | goto audit; | |
439 | } else if ((lperms.allow & MAY_EXEC) && | |
440 | !xindex_is_subset(lperms.xindex, perms.xindex)) { | |
441 | lperms.allow &= ~MAY_EXEC; | |
442 | request |= MAY_EXEC; | |
443 | info = "link not subset of target"; | |
444 | goto audit; | |
445 | } | |
446 | ||
447 | done_tests: | |
448 | error = 0; | |
449 | ||
450 | audit: | |
8014370f JJ |
451 | return aa_audit_file(profile, &lperms, OP_LINK, request, lname, tname, |
452 | NULL, cond->uid, info, error); | |
453 | } | |
454 | ||
455 | /** | |
456 | * aa_path_link - Handle hard link permission check | |
457 | * @label: the label being enforced (NOT NULL) | |
458 | * @old_dentry: the target dentry (NOT NULL) | |
459 | * @new_dir: directory the new link will be created in (NOT NULL) | |
460 | * @new_dentry: the link being created (NOT NULL) | |
461 | * | |
462 | * Handle the permission test for a link & target pair. Permission | |
463 | * is encoded as a pair where the link permission is determined | |
464 | * first, and if allowed, the target is tested. The target test | |
465 | * is done from the point of the link match (not start of DFA) | |
466 | * making the target permission dependent on the link permission match. | |
467 | * | |
468 | * The subset test if required forces that permissions granted | |
469 | * on link are a subset of the permission granted to target. | |
470 | * | |
471 | * Returns: %0 if allowed else error | |
472 | */ | |
473 | int aa_path_link(struct aa_label *label, struct dentry *old_dentry, | |
474 | const struct path *new_dir, struct dentry *new_dentry) | |
475 | { | |
c4758fa5 SR |
476 | struct path link = { .mnt = new_dir->mnt, .dentry = new_dentry }; |
477 | struct path target = { .mnt = new_dir->mnt, .dentry = old_dentry }; | |
8014370f JJ |
478 | struct path_cond cond = { |
479 | d_backing_inode(old_dentry)->i_uid, | |
480 | d_backing_inode(old_dentry)->i_mode | |
481 | }; | |
482 | char *buffer = NULL, *buffer2 = NULL; | |
483 | struct aa_profile *profile; | |
484 | int error; | |
485 | ||
486 | /* buffer freed below, lname is pointer in buffer */ | |
487 | get_buffers(buffer, buffer2); | |
488 | error = fn_for_each_confined(label, profile, | |
489 | profile_path_link(profile, &link, buffer, &target, | |
490 | buffer2, &cond)); | |
4227c333 | 491 | put_buffers(buffer, buffer2); |
6380bd8d JJ |
492 | |
493 | return error; | |
494 | } | |
495 | ||
496c9319 JJ |
496 | static void update_file_ctx(struct aa_file_ctx *fctx, struct aa_label *label, |
497 | u32 request) | |
498 | { | |
499 | struct aa_label *l, *old; | |
500 | ||
501 | /* update caching of label on file_ctx */ | |
502 | spin_lock(&fctx->lock); | |
503 | old = rcu_dereference_protected(fctx->label, | |
504 | spin_is_locked(&fctx->lock)); | |
505 | l = aa_label_merge(old, label, GFP_ATOMIC); | |
506 | if (l) { | |
507 | if (l != old) { | |
508 | rcu_assign_pointer(fctx->label, l); | |
509 | aa_put_label(old); | |
510 | } else | |
511 | aa_put_label(l); | |
512 | fctx->allow |= request; | |
513 | } | |
514 | spin_unlock(&fctx->lock); | |
515 | } | |
516 | ||
517 | static int __file_path_perm(const char *op, struct aa_label *label, | |
518 | struct aa_label *flabel, struct file *file, | |
519 | u32 request, u32 denied) | |
520 | { | |
521 | struct aa_profile *profile; | |
522 | struct aa_perms perms = {}; | |
523 | struct path_cond cond = { | |
524 | .uid = file_inode(file)->i_uid, | |
525 | .mode = file_inode(file)->i_mode | |
526 | }; | |
527 | char *buffer; | |
528 | int flags, error; | |
529 | ||
530 | /* revalidation due to label out of date. No revocation at this time */ | |
531 | if (!denied && aa_label_is_subset(flabel, label)) | |
532 | /* TODO: check for revocation on stale profiles */ | |
533 | return 0; | |
534 | ||
535 | flags = PATH_DELEGATE_DELETED | (S_ISDIR(cond.mode) ? PATH_IS_DIR : 0); | |
536 | get_buffers(buffer); | |
537 | ||
538 | /* check every profile in task label not in current cache */ | |
539 | error = fn_for_each_not_in_set(flabel, label, profile, | |
540 | profile_path_perm(op, profile, &file->f_path, buffer, | |
541 | request, &cond, flags, &perms)); | |
542 | if (denied && !error) { | |
543 | /* | |
544 | * check every profile in file label that was not tested | |
545 | * in the initial check above. | |
546 | * | |
547 | * TODO: cache full perms so this only happens because of | |
548 | * conditionals | |
549 | * TODO: don't audit here | |
550 | */ | |
551 | if (label == flabel) | |
552 | error = fn_for_each(label, profile, | |
553 | profile_path_perm(op, profile, &file->f_path, | |
554 | buffer, request, &cond, flags, | |
555 | &perms)); | |
556 | else | |
557 | error = fn_for_each_not_in_set(label, flabel, profile, | |
558 | profile_path_perm(op, profile, &file->f_path, | |
559 | buffer, request, &cond, flags, | |
560 | &perms)); | |
561 | } | |
562 | if (!error) | |
563 | update_file_ctx(file_ctx(file), label, request); | |
564 | ||
565 | put_buffers(buffer); | |
566 | ||
567 | return error; | |
568 | } | |
569 | ||
695b0eb9 JJ |
570 | static int __file_sock_perm(const char *op, struct aa_label *label, |
571 | struct aa_label *flabel, struct file *file, | |
572 | u32 request, u32 denied) | |
573 | { | |
574 | struct socket *sock = (struct socket *) file->private_data; | |
575 | int error; | |
576 | ||
577 | AA_BUG(!sock); | |
578 | ||
579 | /* revalidation due to label out of date. No revocation at this time */ | |
580 | if (!denied && aa_label_is_subset(flabel, label)) | |
581 | return 0; | |
582 | ||
583 | /* TODO: improve to skip profiles cached in flabel */ | |
584 | error = aa_sock_file_perm(label, op, request, sock); | |
585 | if (denied) { | |
586 | /* TODO: improve to skip profiles checked above */ | |
587 | /* check every profile in file label to is cached */ | |
588 | last_error(error, aa_sock_file_perm(flabel, op, request, sock)); | |
589 | } | |
590 | if (!error) | |
591 | update_file_ctx(file_ctx(file), label, request); | |
592 | ||
593 | return error; | |
594 | } | |
595 | ||
6380bd8d JJ |
596 | /** |
597 | * aa_file_perm - do permission revalidation check & audit for @file | |
598 | * @op: operation being checked | |
190a9518 | 599 | * @label: label being enforced (NOT NULL) |
6380bd8d JJ |
600 | * @file: file to revalidate access permissions on (NOT NULL) |
601 | * @request: requested permissions | |
602 | * | |
603 | * Returns: %0 if access allowed else error | |
604 | */ | |
190a9518 | 605 | int aa_file_perm(const char *op, struct aa_label *label, struct file *file, |
6380bd8d JJ |
606 | u32 request) |
607 | { | |
190a9518 JJ |
608 | struct aa_file_ctx *fctx; |
609 | struct aa_label *flabel; | |
610 | u32 denied; | |
611 | int error = 0; | |
612 | ||
613 | AA_BUG(!label); | |
614 | AA_BUG(!file); | |
615 | ||
616 | fctx = file_ctx(file); | |
617 | ||
618 | rcu_read_lock(); | |
619 | flabel = rcu_dereference(fctx->label); | |
620 | AA_BUG(!flabel); | |
621 | ||
622 | /* revalidate access, if task is unconfined, or the cached cred | |
623 | * doesn't match or if the request is for more permissions than | |
624 | * was granted. | |
625 | * | |
626 | * Note: the test for !unconfined(flabel) is to handle file | |
627 | * delegation from unconfined tasks | |
628 | */ | |
629 | denied = request & ~fctx->allow; | |
630 | if (unconfined(label) || unconfined(flabel) || | |
631 | (!denied && aa_label_is_subset(flabel, label))) | |
632 | goto done; | |
633 | ||
634 | /* TODO: label cross check */ | |
635 | ||
636 | if (file->f_path.mnt && path_mediated_fs(file->f_path.dentry)) | |
496c9319 JJ |
637 | error = __file_path_perm(op, label, flabel, file, request, |
638 | denied); | |
6380bd8d | 639 | |
695b0eb9 JJ |
640 | else if (S_ISSOCK(file_inode(file)->i_mode)) |
641 | error = __file_sock_perm(op, label, flabel, file, request, | |
642 | denied); | |
190a9518 JJ |
643 | done: |
644 | rcu_read_unlock(); | |
645 | ||
646 | return error; | |
6380bd8d | 647 | } |
192ca6b5 | 648 | |
637f688d | 649 | static void revalidate_tty(struct aa_label *label) |
192ca6b5 JJ |
650 | { |
651 | struct tty_struct *tty; | |
652 | int drop_tty = 0; | |
653 | ||
654 | tty = get_current_tty(); | |
655 | if (!tty) | |
656 | return; | |
657 | ||
658 | spin_lock(&tty->files_lock); | |
659 | if (!list_empty(&tty->tty_files)) { | |
660 | struct tty_file_private *file_priv; | |
661 | struct file *file; | |
662 | /* TODO: Revalidate access to controlling tty. */ | |
663 | file_priv = list_first_entry(&tty->tty_files, | |
664 | struct tty_file_private, list); | |
665 | file = file_priv->file; | |
666 | ||
190a9518 | 667 | if (aa_file_perm(OP_INHERIT, label, file, MAY_READ | MAY_WRITE)) |
192ca6b5 JJ |
668 | drop_tty = 1; |
669 | } | |
670 | spin_unlock(&tty->files_lock); | |
671 | tty_kref_put(tty); | |
672 | ||
673 | if (drop_tty) | |
674 | no_tty(); | |
675 | } | |
676 | ||
677 | static int match_file(const void *p, struct file *file, unsigned int fd) | |
678 | { | |
637f688d | 679 | struct aa_label *label = (struct aa_label *)p; |
192ca6b5 | 680 | |
190a9518 | 681 | if (aa_file_perm(OP_INHERIT, label, file, aa_map_file_to_perms(file))) |
192ca6b5 JJ |
682 | return fd + 1; |
683 | return 0; | |
684 | } | |
685 | ||
686 | ||
687 | /* based on selinux's flush_unauthorized_files */ | |
688 | void aa_inherit_files(const struct cred *cred, struct files_struct *files) | |
689 | { | |
637f688d | 690 | struct aa_label *label = aa_get_newest_cred_label(cred); |
192ca6b5 JJ |
691 | struct file *devnull = NULL; |
692 | unsigned int n; | |
693 | ||
637f688d | 694 | revalidate_tty(label); |
192ca6b5 JJ |
695 | |
696 | /* Revalidate access to inherited open files. */ | |
637f688d | 697 | n = iterate_fd(files, 0, match_file, label); |
192ca6b5 JJ |
698 | if (!n) /* none found? */ |
699 | goto out; | |
700 | ||
701 | devnull = dentry_open(&aa_null, O_RDWR, cred); | |
702 | if (IS_ERR(devnull)) | |
703 | devnull = NULL; | |
704 | /* replace all the matching ones with this */ | |
705 | do { | |
706 | replace_fd(n - 1, devnull, 0); | |
637f688d | 707 | } while ((n = iterate_fd(files, n, match_file, label)) != 0); |
192ca6b5 JJ |
708 | if (devnull) |
709 | fput(devnull); | |
710 | out: | |
637f688d | 711 | aa_put_label(label); |
192ca6b5 | 712 | } |