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