Commit | Line | Data |
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b886d83c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
6380bd8d JJ |
2 | /* |
3 | * AppArmor security module | |
4 | * | |
5 | * This file contains AppArmor mediation of files | |
6 | * | |
7 | * Copyright (C) 1998-2008 Novell/SUSE | |
8 | * Copyright 2009-2010 Canonical Ltd. | |
6380bd8d JJ |
9 | */ |
10 | ||
192ca6b5 JJ |
11 | #include <linux/tty.h> |
12 | #include <linux/fdtable.h> | |
13 | #include <linux/file.h> | |
14 | ||
6380bd8d JJ |
15 | #include "include/apparmor.h" |
16 | #include "include/audit.h" | |
d8889d49 | 17 | #include "include/cred.h" |
6380bd8d JJ |
18 | #include "include/file.h" |
19 | #include "include/match.h" | |
56974a6f | 20 | #include "include/net.h" |
6380bd8d JJ |
21 | #include "include/path.h" |
22 | #include "include/policy.h" | |
190a9518 | 23 | #include "include/label.h" |
6380bd8d | 24 | |
e53cfe6c JJ |
25 | static u32 map_mask_to_chr_mask(u32 mask) |
26 | { | |
27 | u32 m = mask & PERMS_CHRS_MASK; | |
28 | ||
29 | if (mask & AA_MAY_GETATTR) | |
30 | m |= MAY_READ; | |
31 | if (mask & (AA_MAY_SETATTR | AA_MAY_CHMOD | AA_MAY_CHOWN)) | |
32 | m |= MAY_WRITE; | |
33 | ||
34 | return m; | |
35 | } | |
6380bd8d JJ |
36 | |
37 | /** | |
38 | * audit_file_mask - convert mask to permission string | |
39 | * @buffer: buffer to write string to (NOT NULL) | |
40 | * @mask: permission mask to convert | |
41 | */ | |
42 | static void audit_file_mask(struct audit_buffer *ab, u32 mask) | |
43 | { | |
44 | char str[10]; | |
45 | ||
7f3ebcf2 TH |
46 | aa_perm_mask_to_str(str, sizeof(str), aa_file_perm_chrs, |
47 | map_mask_to_chr_mask(mask)); | |
6380bd8d JJ |
48 | audit_log_string(ab, str); |
49 | } | |
50 | ||
51 | /** | |
52 | * file_audit_cb - call back for file specific audit fields | |
53 | * @ab: audit_buffer (NOT NULL) | |
54 | * @va: audit struct to audit values of (NOT NULL) | |
55 | */ | |
56 | static void file_audit_cb(struct audit_buffer *ab, void *va) | |
57 | { | |
58 | struct common_audit_data *sa = va; | |
2db81452 | 59 | kuid_t fsuid = current_fsuid(); |
6380bd8d | 60 | |
aa9aeea8 | 61 | if (aad(sa)->request & AA_AUDIT_FILE_MASK) { |
6380bd8d | 62 | audit_log_format(ab, " requested_mask="); |
aa9aeea8 | 63 | audit_file_mask(ab, aad(sa)->request); |
6380bd8d | 64 | } |
aa9aeea8 | 65 | if (aad(sa)->denied & AA_AUDIT_FILE_MASK) { |
6380bd8d | 66 | audit_log_format(ab, " denied_mask="); |
aa9aeea8 | 67 | audit_file_mask(ab, aad(sa)->denied); |
6380bd8d | 68 | } |
aa9aeea8 | 69 | if (aad(sa)->request & AA_AUDIT_FILE_MASK) { |
2db81452 EB |
70 | audit_log_format(ab, " fsuid=%d", |
71 | from_kuid(&init_user_ns, fsuid)); | |
72 | audit_log_format(ab, " ouid=%d", | |
ef88a7ac | 73 | from_kuid(&init_user_ns, aad(sa)->fs.ouid)); |
6380bd8d JJ |
74 | } |
75 | ||
98c3d182 JJ |
76 | if (aad(sa)->peer) { |
77 | audit_log_format(ab, " target="); | |
78 | aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer, | |
79 | FLAG_VIEW_SUBNS, GFP_ATOMIC); | |
80 | } else if (aad(sa)->fs.target) { | |
6380bd8d | 81 | audit_log_format(ab, " target="); |
ef88a7ac | 82 | audit_log_untrustedstring(ab, aad(sa)->fs.target); |
6380bd8d JJ |
83 | } |
84 | } | |
85 | ||
86 | /** | |
87 | * aa_audit_file - handle the auditing of file operations | |
88 | * @profile: the profile being enforced (NOT NULL) | |
89 | * @perms: the permissions computed for the request (NOT NULL) | |
6380bd8d JJ |
90 | * @op: operation being mediated |
91 | * @request: permissions requested | |
92 | * @name: name of object being mediated (MAYBE NULL) | |
93 | * @target: name of target (MAYBE NULL) | |
98c3d182 | 94 | * @tlabel: target label (MAY BE NULL) |
6380bd8d JJ |
95 | * @ouid: object uid |
96 | * @info: extra information message (MAYBE NULL) | |
97 | * @error: 0 if operation allowed else failure error code | |
98 | * | |
99 | * Returns: %0 or error on failure | |
100 | */ | |
2d679f3c | 101 | int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms, |
ef88a7ac | 102 | const char *op, u32 request, const char *name, |
98c3d182 JJ |
103 | const char *target, struct aa_label *tlabel, |
104 | kuid_t ouid, const char *info, int error) | |
6380bd8d JJ |
105 | { |
106 | int type = AUDIT_APPARMOR_AUTO; | |
ef88a7ac JJ |
107 | DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_TASK, op); |
108 | ||
109 | sa.u.tsk = NULL; | |
aa9aeea8 | 110 | aad(&sa)->request = request; |
ef88a7ac JJ |
111 | aad(&sa)->name = name; |
112 | aad(&sa)->fs.target = target; | |
98c3d182 | 113 | aad(&sa)->peer = tlabel; |
ef88a7ac JJ |
114 | aad(&sa)->fs.ouid = ouid; |
115 | aad(&sa)->info = info; | |
116 | aad(&sa)->error = error; | |
b6b1b81b | 117 | sa.u.tsk = NULL; |
ef88a7ac JJ |
118 | |
119 | if (likely(!aad(&sa)->error)) { | |
6380bd8d JJ |
120 | u32 mask = perms->audit; |
121 | ||
122 | if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL)) | |
123 | mask = 0xffff; | |
124 | ||
125 | /* mask off perms that are not being force audited */ | |
aa9aeea8 | 126 | aad(&sa)->request &= mask; |
6380bd8d | 127 | |
aa9aeea8 | 128 | if (likely(!aad(&sa)->request)) |
6380bd8d JJ |
129 | return 0; |
130 | type = AUDIT_APPARMOR_AUDIT; | |
131 | } else { | |
132 | /* only report permissions that were denied */ | |
aa9aeea8 JJ |
133 | aad(&sa)->request = aad(&sa)->request & ~perms->allow; |
134 | AA_BUG(!aad(&sa)->request); | |
6380bd8d | 135 | |
aa9aeea8 | 136 | if (aad(&sa)->request & perms->kill) |
6380bd8d JJ |
137 | type = AUDIT_APPARMOR_KILL; |
138 | ||
139 | /* quiet known rejects, assumes quiet and kill do not overlap */ | |
aa9aeea8 | 140 | if ((aad(&sa)->request & perms->quiet) && |
6380bd8d JJ |
141 | AUDIT_MODE(profile) != AUDIT_NOQUIET && |
142 | AUDIT_MODE(profile) != AUDIT_ALL) | |
aa9aeea8 | 143 | aad(&sa)->request &= ~perms->quiet; |
6380bd8d | 144 | |
aa9aeea8 | 145 | if (!aad(&sa)->request) |
98c3d182 | 146 | return aad(&sa)->error; |
6380bd8d JJ |
147 | } |
148 | ||
aa9aeea8 | 149 | aad(&sa)->denied = aad(&sa)->request & ~perms->allow; |
ef88a7ac | 150 | return aa_audit(type, profile, &sa, file_audit_cb); |
6380bd8d JJ |
151 | } |
152 | ||
aebd873e JJ |
153 | /** |
154 | * is_deleted - test if a file has been completely unlinked | |
155 | * @dentry: dentry of file to test for deletion (NOT NULL) | |
156 | * | |
157 | * Returns: %1 if deleted else %0 | |
158 | */ | |
159 | static inline bool is_deleted(struct dentry *dentry) | |
160 | { | |
161 | if (d_unlinked(dentry) && d_backing_inode(dentry)->i_nlink == 0) | |
162 | return 1; | |
163 | return 0; | |
164 | } | |
165 | ||
166 | static int path_name(const char *op, struct aa_label *label, | |
167 | const struct path *path, int flags, char *buffer, | |
168 | const char **name, struct path_cond *cond, u32 request) | |
169 | { | |
170 | struct aa_profile *profile; | |
171 | const char *info = NULL; | |
172 | int error; | |
173 | ||
174 | error = aa_path_name(path, flags, buffer, name, &info, | |
175 | labels_profile(label)->disconnected); | |
176 | if (error) { | |
177 | fn_for_each_confined(label, profile, | |
178 | aa_audit_file(profile, &nullperms, op, request, *name, | |
179 | NULL, NULL, cond->uid, info, error)); | |
180 | return error; | |
181 | } | |
182 | ||
183 | return 0; | |
184 | } | |
185 | ||
6380bd8d JJ |
186 | /** |
187 | * map_old_perms - map old file perms layout to the new layout | |
188 | * @old: permission set in old mapping | |
189 | * | |
190 | * Returns: new permission mapping | |
191 | */ | |
192 | static u32 map_old_perms(u32 old) | |
193 | { | |
194 | u32 new = old & 0xf; | |
195 | if (old & MAY_READ) | |
e53cfe6c | 196 | new |= AA_MAY_GETATTR | AA_MAY_OPEN; |
6380bd8d | 197 | if (old & MAY_WRITE) |
e53cfe6c JJ |
198 | new |= AA_MAY_SETATTR | AA_MAY_CREATE | AA_MAY_DELETE | |
199 | AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_OPEN; | |
6380bd8d JJ |
200 | if (old & 0x10) |
201 | new |= AA_MAY_LINK; | |
202 | /* the old mapping lock and link_subset flags where overlaid | |
203 | * and use was determined by part of a pair that they were in | |
204 | */ | |
205 | if (old & 0x20) | |
206 | new |= AA_MAY_LOCK | AA_LINK_SUBSET; | |
207 | if (old & 0x40) /* AA_EXEC_MMAP */ | |
208 | new |= AA_EXEC_MMAP; | |
209 | ||
6380bd8d JJ |
210 | return new; |
211 | } | |
212 | ||
213 | /** | |
2d679f3c | 214 | * aa_compute_fperms - convert dfa compressed perms to internal perms |
6380bd8d JJ |
215 | * @dfa: dfa to compute perms for (NOT NULL) |
216 | * @state: state in dfa | |
217 | * @cond: conditions to consider (NOT NULL) | |
218 | * | |
219 | * TODO: convert from dfa + state to permission entry, do computation conversion | |
220 | * at load time. | |
221 | * | |
222 | * Returns: computed permission set | |
223 | */ | |
2d679f3c JJ |
224 | struct aa_perms aa_compute_fperms(struct aa_dfa *dfa, unsigned int state, |
225 | struct path_cond *cond) | |
6380bd8d | 226 | { |
6380bd8d JJ |
227 | /* FIXME: change over to new dfa format |
228 | * currently file perms are encoded in the dfa, new format | |
229 | * splits the permissions from the dfa. This mapping can be | |
230 | * done at profile load | |
231 | */ | |
7bba39ae | 232 | struct aa_perms perms = { }; |
6380bd8d | 233 | |
2db81452 | 234 | if (uid_eq(current_fsuid(), cond->uid)) { |
6380bd8d JJ |
235 | perms.allow = map_old_perms(dfa_user_allow(dfa, state)); |
236 | perms.audit = map_old_perms(dfa_user_audit(dfa, state)); | |
237 | perms.quiet = map_old_perms(dfa_user_quiet(dfa, state)); | |
238 | perms.xindex = dfa_user_xindex(dfa, state); | |
239 | } else { | |
240 | perms.allow = map_old_perms(dfa_other_allow(dfa, state)); | |
241 | perms.audit = map_old_perms(dfa_other_audit(dfa, state)); | |
242 | perms.quiet = map_old_perms(dfa_other_quiet(dfa, state)); | |
243 | perms.xindex = dfa_other_xindex(dfa, state); | |
244 | } | |
e53cfe6c | 245 | perms.allow |= AA_MAY_GETATTR; |
6380bd8d JJ |
246 | |
247 | /* change_profile wasn't determined by ownership in old mapping */ | |
248 | if (ACCEPT_TABLE(dfa)[state] & 0x80000000) | |
249 | perms.allow |= AA_MAY_CHANGE_PROFILE; | |
0421ea91 JJ |
250 | if (ACCEPT_TABLE(dfa)[state] & 0x40000000) |
251 | perms.allow |= AA_MAY_ONEXEC; | |
6380bd8d JJ |
252 | |
253 | return perms; | |
254 | } | |
255 | ||
256 | /** | |
257 | * aa_str_perms - find permission that match @name | |
258 | * @dfa: to match against (MAYBE NULL) | |
259 | * @state: state to start matching in | |
260 | * @name: string to match against dfa (NOT NULL) | |
261 | * @cond: conditions to consider for permission set computation (NOT NULL) | |
262 | * @perms: Returns - the permissions found when matching @name | |
263 | * | |
264 | * Returns: the final state in @dfa when beginning @start and walking @name | |
265 | */ | |
266 | unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start, | |
267 | const char *name, struct path_cond *cond, | |
2d679f3c | 268 | struct aa_perms *perms) |
6380bd8d JJ |
269 | { |
270 | unsigned int state; | |
6380bd8d | 271 | state = aa_dfa_match(dfa, start, name); |
2d679f3c | 272 | *perms = aa_compute_fperms(dfa, state, cond); |
6380bd8d JJ |
273 | |
274 | return state; | |
275 | } | |
276 | ||
aebd873e JJ |
277 | int __aa_path_perm(const char *op, struct aa_profile *profile, const char *name, |
278 | u32 request, struct path_cond *cond, int flags, | |
279 | struct aa_perms *perms) | |
6380bd8d | 280 | { |
aebd873e JJ |
281 | int e = 0; |
282 | ||
283 | if (profile_unconfined(profile)) | |
284 | return 0; | |
285 | aa_str_perms(profile->file.dfa, profile->file.start, name, cond, perms); | |
286 | if (request & ~perms->allow) | |
287 | e = -EACCES; | |
288 | return aa_audit_file(profile, perms, op, request, name, NULL, NULL, | |
289 | cond->uid, NULL, e); | |
290 | } | |
291 | ||
292 | ||
293 | static int profile_path_perm(const char *op, struct aa_profile *profile, | |
294 | const struct path *path, char *buffer, u32 request, | |
295 | struct path_cond *cond, int flags, | |
296 | struct aa_perms *perms) | |
297 | { | |
298 | const char *name; | |
299 | int error; | |
300 | ||
301 | if (profile_unconfined(profile)) | |
302 | return 0; | |
303 | ||
304 | error = path_name(op, &profile->label, path, | |
305 | flags | profile->path_flags, buffer, &name, cond, | |
306 | request); | |
307 | if (error) | |
308 | return error; | |
309 | return __aa_path_perm(op, profile, name, request, cond, flags, | |
310 | perms); | |
6380bd8d JJ |
311 | } |
312 | ||
313 | /** | |
314 | * aa_path_perm - do permissions check & audit for @path | |
315 | * @op: operation being checked | |
aebd873e | 316 | * @label: profile being enforced (NOT NULL) |
6380bd8d JJ |
317 | * @path: path to check permissions of (NOT NULL) |
318 | * @flags: any additional path flags beyond what the profile specifies | |
319 | * @request: requested permissions | |
320 | * @cond: conditional info for this request (NOT NULL) | |
321 | * | |
322 | * Returns: %0 else error if access denied or other error | |
323 | */ | |
aebd873e | 324 | int aa_path_perm(const char *op, struct aa_label *label, |
47f6e5cc JJ |
325 | const struct path *path, int flags, u32 request, |
326 | struct path_cond *cond) | |
6380bd8d | 327 | { |
2d679f3c | 328 | struct aa_perms perms = {}; |
aebd873e JJ |
329 | struct aa_profile *profile; |
330 | char *buffer = NULL; | |
6380bd8d JJ |
331 | int error; |
332 | ||
aebd873e JJ |
333 | flags |= PATH_DELEGATE_DELETED | (S_ISDIR(cond->mode) ? PATH_IS_DIR : |
334 | 0); | |
4227c333 | 335 | get_buffers(buffer); |
aebd873e JJ |
336 | error = fn_for_each_confined(label, profile, |
337 | profile_path_perm(op, profile, path, buffer, request, | |
338 | cond, flags, &perms)); | |
339 | ||
4227c333 | 340 | put_buffers(buffer); |
6380bd8d JJ |
341 | |
342 | return error; | |
343 | } | |
344 | ||
345 | /** | |
346 | * xindex_is_subset - helper for aa_path_link | |
347 | * @link: link permission set | |
348 | * @target: target permission set | |
349 | * | |
350 | * test target x permissions are equal OR a subset of link x permissions | |
351 | * this is done as part of the subset test, where a hardlink must have | |
352 | * a subset of permissions that the target has. | |
353 | * | |
354 | * Returns: %1 if subset else %0 | |
355 | */ | |
356 | static inline bool xindex_is_subset(u32 link, u32 target) | |
357 | { | |
358 | if (((link & ~AA_X_UNSAFE) != (target & ~AA_X_UNSAFE)) || | |
359 | ((link & AA_X_UNSAFE) && !(target & AA_X_UNSAFE))) | |
360 | return 0; | |
361 | ||
362 | return 1; | |
363 | } | |
364 | ||
8014370f JJ |
365 | static int profile_path_link(struct aa_profile *profile, |
366 | const struct path *link, char *buffer, | |
367 | const struct path *target, char *buffer2, | |
368 | struct path_cond *cond) | |
6380bd8d | 369 | { |
8014370f JJ |
370 | const char *lname, *tname = NULL; |
371 | struct aa_perms lperms = {}, perms; | |
372 | const char *info = NULL; | |
6380bd8d JJ |
373 | u32 request = AA_MAY_LINK; |
374 | unsigned int state; | |
375 | int error; | |
376 | ||
8014370f JJ |
377 | error = path_name(OP_LINK, &profile->label, link, profile->path_flags, |
378 | buffer, &lname, cond, AA_MAY_LINK); | |
6380bd8d JJ |
379 | if (error) |
380 | goto audit; | |
381 | ||
382 | /* buffer2 freed below, tname is pointer in buffer2 */ | |
8014370f JJ |
383 | error = path_name(OP_LINK, &profile->label, target, profile->path_flags, |
384 | buffer2, &tname, cond, AA_MAY_LINK); | |
6380bd8d JJ |
385 | if (error) |
386 | goto audit; | |
387 | ||
388 | error = -EACCES; | |
389 | /* aa_str_perms - handles the case of the dfa being NULL */ | |
390 | state = aa_str_perms(profile->file.dfa, profile->file.start, lname, | |
8014370f | 391 | cond, &lperms); |
6380bd8d JJ |
392 | |
393 | if (!(lperms.allow & AA_MAY_LINK)) | |
394 | goto audit; | |
395 | ||
396 | /* test to see if target can be paired with link */ | |
397 | state = aa_dfa_null_transition(profile->file.dfa, state); | |
8014370f | 398 | aa_str_perms(profile->file.dfa, state, tname, cond, &perms); |
6380bd8d JJ |
399 | |
400 | /* force audit/quiet masks for link are stored in the second entry | |
401 | * in the link pair. | |
402 | */ | |
403 | lperms.audit = perms.audit; | |
404 | lperms.quiet = perms.quiet; | |
405 | lperms.kill = perms.kill; | |
406 | ||
407 | if (!(perms.allow & AA_MAY_LINK)) { | |
408 | info = "target restricted"; | |
8014370f | 409 | lperms = perms; |
6380bd8d JJ |
410 | goto audit; |
411 | } | |
412 | ||
413 | /* done if link subset test is not required */ | |
414 | if (!(perms.allow & AA_LINK_SUBSET)) | |
415 | goto done_tests; | |
416 | ||
8014370f JJ |
417 | /* Do link perm subset test requiring allowed permission on link are |
418 | * a subset of the allowed permissions on target. | |
6380bd8d | 419 | */ |
8014370f | 420 | aa_str_perms(profile->file.dfa, profile->file.start, tname, cond, |
6380bd8d JJ |
421 | &perms); |
422 | ||
423 | /* AA_MAY_LINK is not considered in the subset test */ | |
424 | request = lperms.allow & ~AA_MAY_LINK; | |
425 | lperms.allow &= perms.allow | AA_MAY_LINK; | |
426 | ||
427 | request |= AA_AUDIT_FILE_MASK & (lperms.allow & ~perms.allow); | |
428 | if (request & ~lperms.allow) { | |
429 | goto audit; | |
430 | } else if ((lperms.allow & MAY_EXEC) && | |
431 | !xindex_is_subset(lperms.xindex, perms.xindex)) { | |
432 | lperms.allow &= ~MAY_EXEC; | |
433 | request |= MAY_EXEC; | |
434 | info = "link not subset of target"; | |
435 | goto audit; | |
436 | } | |
437 | ||
438 | done_tests: | |
439 | error = 0; | |
440 | ||
441 | audit: | |
8014370f JJ |
442 | return aa_audit_file(profile, &lperms, OP_LINK, request, lname, tname, |
443 | NULL, cond->uid, info, error); | |
444 | } | |
445 | ||
446 | /** | |
447 | * aa_path_link - Handle hard link permission check | |
448 | * @label: the label being enforced (NOT NULL) | |
449 | * @old_dentry: the target dentry (NOT NULL) | |
450 | * @new_dir: directory the new link will be created in (NOT NULL) | |
451 | * @new_dentry: the link being created (NOT NULL) | |
452 | * | |
453 | * Handle the permission test for a link & target pair. Permission | |
454 | * is encoded as a pair where the link permission is determined | |
455 | * first, and if allowed, the target is tested. The target test | |
456 | * is done from the point of the link match (not start of DFA) | |
457 | * making the target permission dependent on the link permission match. | |
458 | * | |
459 | * The subset test if required forces that permissions granted | |
460 | * on link are a subset of the permission granted to target. | |
461 | * | |
462 | * Returns: %0 if allowed else error | |
463 | */ | |
464 | int aa_path_link(struct aa_label *label, struct dentry *old_dentry, | |
465 | const struct path *new_dir, struct dentry *new_dentry) | |
466 | { | |
c4758fa5 SR |
467 | struct path link = { .mnt = new_dir->mnt, .dentry = new_dentry }; |
468 | struct path target = { .mnt = new_dir->mnt, .dentry = old_dentry }; | |
8014370f JJ |
469 | struct path_cond cond = { |
470 | d_backing_inode(old_dentry)->i_uid, | |
471 | d_backing_inode(old_dentry)->i_mode | |
472 | }; | |
473 | char *buffer = NULL, *buffer2 = NULL; | |
474 | struct aa_profile *profile; | |
475 | int error; | |
476 | ||
477 | /* buffer freed below, lname is pointer in buffer */ | |
478 | get_buffers(buffer, buffer2); | |
479 | error = fn_for_each_confined(label, profile, | |
480 | profile_path_link(profile, &link, buffer, &target, | |
481 | buffer2, &cond)); | |
4227c333 | 482 | put_buffers(buffer, buffer2); |
6380bd8d JJ |
483 | |
484 | return error; | |
485 | } | |
486 | ||
496c9319 JJ |
487 | static void update_file_ctx(struct aa_file_ctx *fctx, struct aa_label *label, |
488 | u32 request) | |
489 | { | |
490 | struct aa_label *l, *old; | |
491 | ||
492 | /* update caching of label on file_ctx */ | |
493 | spin_lock(&fctx->lock); | |
494 | old = rcu_dereference_protected(fctx->label, | |
0fb871cc | 495 | lockdep_is_held(&fctx->lock)); |
496c9319 JJ |
496 | l = aa_label_merge(old, label, GFP_ATOMIC); |
497 | if (l) { | |
498 | if (l != old) { | |
499 | rcu_assign_pointer(fctx->label, l); | |
500 | aa_put_label(old); | |
501 | } else | |
502 | aa_put_label(l); | |
503 | fctx->allow |= request; | |
504 | } | |
505 | spin_unlock(&fctx->lock); | |
506 | } | |
507 | ||
508 | static int __file_path_perm(const char *op, struct aa_label *label, | |
509 | struct aa_label *flabel, struct file *file, | |
510 | u32 request, u32 denied) | |
511 | { | |
512 | struct aa_profile *profile; | |
513 | struct aa_perms perms = {}; | |
514 | struct path_cond cond = { | |
515 | .uid = file_inode(file)->i_uid, | |
516 | .mode = file_inode(file)->i_mode | |
517 | }; | |
518 | char *buffer; | |
519 | int flags, error; | |
520 | ||
521 | /* revalidation due to label out of date. No revocation at this time */ | |
522 | if (!denied && aa_label_is_subset(flabel, label)) | |
523 | /* TODO: check for revocation on stale profiles */ | |
524 | return 0; | |
525 | ||
526 | flags = PATH_DELEGATE_DELETED | (S_ISDIR(cond.mode) ? PATH_IS_DIR : 0); | |
527 | get_buffers(buffer); | |
528 | ||
529 | /* check every profile in task label not in current cache */ | |
530 | error = fn_for_each_not_in_set(flabel, label, profile, | |
531 | profile_path_perm(op, profile, &file->f_path, buffer, | |
532 | request, &cond, flags, &perms)); | |
533 | if (denied && !error) { | |
534 | /* | |
535 | * check every profile in file label that was not tested | |
536 | * in the initial check above. | |
537 | * | |
538 | * TODO: cache full perms so this only happens because of | |
539 | * conditionals | |
540 | * TODO: don't audit here | |
541 | */ | |
542 | if (label == flabel) | |
543 | error = fn_for_each(label, profile, | |
544 | profile_path_perm(op, profile, &file->f_path, | |
545 | buffer, request, &cond, flags, | |
546 | &perms)); | |
547 | else | |
548 | error = fn_for_each_not_in_set(label, flabel, profile, | |
549 | profile_path_perm(op, profile, &file->f_path, | |
550 | buffer, request, &cond, flags, | |
551 | &perms)); | |
552 | } | |
553 | if (!error) | |
554 | update_file_ctx(file_ctx(file), label, request); | |
555 | ||
556 | put_buffers(buffer); | |
557 | ||
558 | return error; | |
559 | } | |
560 | ||
56974a6f JJ |
561 | static int __file_sock_perm(const char *op, struct aa_label *label, |
562 | struct aa_label *flabel, struct file *file, | |
563 | u32 request, u32 denied) | |
564 | { | |
565 | struct socket *sock = (struct socket *) file->private_data; | |
566 | int error; | |
567 | ||
568 | AA_BUG(!sock); | |
569 | ||
570 | /* revalidation due to label out of date. No revocation at this time */ | |
571 | if (!denied && aa_label_is_subset(flabel, label)) | |
572 | return 0; | |
573 | ||
574 | /* TODO: improve to skip profiles cached in flabel */ | |
575 | error = aa_sock_file_perm(label, op, request, sock); | |
576 | if (denied) { | |
577 | /* TODO: improve to skip profiles checked above */ | |
578 | /* check every profile in file label to is cached */ | |
579 | last_error(error, aa_sock_file_perm(flabel, op, request, sock)); | |
580 | } | |
581 | if (!error) | |
582 | update_file_ctx(file_ctx(file), label, request); | |
583 | ||
584 | return error; | |
585 | } | |
586 | ||
6380bd8d JJ |
587 | /** |
588 | * aa_file_perm - do permission revalidation check & audit for @file | |
589 | * @op: operation being checked | |
190a9518 | 590 | * @label: label being enforced (NOT NULL) |
6380bd8d JJ |
591 | * @file: file to revalidate access permissions on (NOT NULL) |
592 | * @request: requested permissions | |
593 | * | |
594 | * Returns: %0 if access allowed else error | |
595 | */ | |
190a9518 | 596 | int aa_file_perm(const char *op, struct aa_label *label, struct file *file, |
6380bd8d JJ |
597 | u32 request) |
598 | { | |
190a9518 JJ |
599 | struct aa_file_ctx *fctx; |
600 | struct aa_label *flabel; | |
601 | u32 denied; | |
602 | int error = 0; | |
603 | ||
604 | AA_BUG(!label); | |
605 | AA_BUG(!file); | |
606 | ||
607 | fctx = file_ctx(file); | |
608 | ||
609 | rcu_read_lock(); | |
610 | flabel = rcu_dereference(fctx->label); | |
611 | AA_BUG(!flabel); | |
612 | ||
613 | /* revalidate access, if task is unconfined, or the cached cred | |
614 | * doesn't match or if the request is for more permissions than | |
615 | * was granted. | |
616 | * | |
617 | * Note: the test for !unconfined(flabel) is to handle file | |
618 | * delegation from unconfined tasks | |
619 | */ | |
620 | denied = request & ~fctx->allow; | |
621 | if (unconfined(label) || unconfined(flabel) || | |
622 | (!denied && aa_label_is_subset(flabel, label))) | |
623 | goto done; | |
624 | ||
625 | /* TODO: label cross check */ | |
626 | ||
627 | if (file->f_path.mnt && path_mediated_fs(file->f_path.dentry)) | |
496c9319 JJ |
628 | error = __file_path_perm(op, label, flabel, file, request, |
629 | denied); | |
6380bd8d | 630 | |
56974a6f JJ |
631 | else if (S_ISSOCK(file_inode(file)->i_mode)) |
632 | error = __file_sock_perm(op, label, flabel, file, request, | |
633 | denied); | |
190a9518 JJ |
634 | done: |
635 | rcu_read_unlock(); | |
636 | ||
637 | return error; | |
6380bd8d | 638 | } |
192ca6b5 | 639 | |
637f688d | 640 | static void revalidate_tty(struct aa_label *label) |
192ca6b5 JJ |
641 | { |
642 | struct tty_struct *tty; | |
643 | int drop_tty = 0; | |
644 | ||
645 | tty = get_current_tty(); | |
646 | if (!tty) | |
647 | return; | |
648 | ||
649 | spin_lock(&tty->files_lock); | |
650 | if (!list_empty(&tty->tty_files)) { | |
651 | struct tty_file_private *file_priv; | |
652 | struct file *file; | |
653 | /* TODO: Revalidate access to controlling tty. */ | |
654 | file_priv = list_first_entry(&tty->tty_files, | |
655 | struct tty_file_private, list); | |
656 | file = file_priv->file; | |
657 | ||
190a9518 | 658 | if (aa_file_perm(OP_INHERIT, label, file, MAY_READ | MAY_WRITE)) |
192ca6b5 JJ |
659 | drop_tty = 1; |
660 | } | |
661 | spin_unlock(&tty->files_lock); | |
662 | tty_kref_put(tty); | |
663 | ||
664 | if (drop_tty) | |
665 | no_tty(); | |
666 | } | |
667 | ||
668 | static int match_file(const void *p, struct file *file, unsigned int fd) | |
669 | { | |
637f688d | 670 | struct aa_label *label = (struct aa_label *)p; |
192ca6b5 | 671 | |
190a9518 | 672 | if (aa_file_perm(OP_INHERIT, label, file, aa_map_file_to_perms(file))) |
192ca6b5 JJ |
673 | return fd + 1; |
674 | return 0; | |
675 | } | |
676 | ||
677 | ||
678 | /* based on selinux's flush_unauthorized_files */ | |
679 | void aa_inherit_files(const struct cred *cred, struct files_struct *files) | |
680 | { | |
637f688d | 681 | struct aa_label *label = aa_get_newest_cred_label(cred); |
192ca6b5 JJ |
682 | struct file *devnull = NULL; |
683 | unsigned int n; | |
684 | ||
637f688d | 685 | revalidate_tty(label); |
192ca6b5 JJ |
686 | |
687 | /* Revalidate access to inherited open files. */ | |
637f688d | 688 | n = iterate_fd(files, 0, match_file, label); |
192ca6b5 JJ |
689 | if (!n) /* none found? */ |
690 | goto out; | |
691 | ||
692 | devnull = dentry_open(&aa_null, O_RDWR, cred); | |
693 | if (IS_ERR(devnull)) | |
694 | devnull = NULL; | |
695 | /* replace all the matching ones with this */ | |
696 | do { | |
697 | replace_fd(n - 1, devnull, 0); | |
637f688d | 698 | } while ((n = iterate_fd(files, n, match_file, label)) != 0); |
192ca6b5 JJ |
699 | if (devnull) |
700 | fput(devnull); | |
701 | out: | |
637f688d | 702 | aa_put_label(label); |
192ca6b5 | 703 | } |