Commit | Line | Data |
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898127c3 JJ |
1 | /* |
2 | * AppArmor security module | |
3 | * | |
4 | * This file contains AppArmor policy attachment and domain transitions | |
5 | * | |
6 | * Copyright (C) 2002-2008 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 | ||
15 | #include <linux/errno.h> | |
16 | #include <linux/fdtable.h> | |
17 | #include <linux/file.h> | |
18 | #include <linux/mount.h> | |
19 | #include <linux/syscalls.h> | |
20 | #include <linux/tracehook.h> | |
21 | #include <linux/personality.h> | |
22 | ||
23 | #include "include/audit.h" | |
24 | #include "include/apparmorfs.h" | |
25 | #include "include/context.h" | |
26 | #include "include/domain.h" | |
27 | #include "include/file.h" | |
28 | #include "include/ipc.h" | |
29 | #include "include/match.h" | |
30 | #include "include/path.h" | |
31 | #include "include/policy.h" | |
32 | ||
33 | /** | |
34 | * aa_free_domain_entries - free entries in a domain table | |
35 | * @domain: the domain table to free (MAYBE NULL) | |
36 | */ | |
37 | void aa_free_domain_entries(struct aa_domain *domain) | |
38 | { | |
39 | int i; | |
40 | if (domain) { | |
41 | if (!domain->table) | |
42 | return; | |
43 | ||
44 | for (i = 0; i < domain->size; i++) | |
45 | kzfree(domain->table[i]); | |
46 | kzfree(domain->table); | |
47 | domain->table = NULL; | |
48 | } | |
49 | } | |
50 | ||
51 | /** | |
52 | * may_change_ptraced_domain - check if can change profile on ptraced task | |
898127c3 JJ |
53 | * @to_profile: profile to change to (NOT NULL) |
54 | * | |
51775fe7 | 55 | * Check if current is ptraced and if so if the tracing task is allowed |
898127c3 JJ |
56 | * to trace the new domain |
57 | * | |
58 | * Returns: %0 or error if change not allowed | |
59 | */ | |
51775fe7 | 60 | static int may_change_ptraced_domain(struct aa_profile *to_profile) |
898127c3 JJ |
61 | { |
62 | struct task_struct *tracer; | |
898127c3 JJ |
63 | struct aa_profile *tracerp = NULL; |
64 | int error = 0; | |
65 | ||
66 | rcu_read_lock(); | |
51775fe7 | 67 | tracer = ptrace_parent(current); |
3cfcc19e | 68 | if (tracer) |
898127c3 | 69 | /* released below */ |
3cfcc19e | 70 | tracerp = aa_get_task_profile(tracer); |
898127c3 JJ |
71 | |
72 | /* not ptraced */ | |
73 | if (!tracer || unconfined(tracerp)) | |
74 | goto out; | |
75 | ||
dd0c6e86 | 76 | error = aa_may_ptrace(tracerp, to_profile, PTRACE_MODE_ATTACH); |
898127c3 JJ |
77 | |
78 | out: | |
04fdc099 | 79 | rcu_read_unlock(); |
3cfcc19e | 80 | aa_put_profile(tracerp); |
898127c3 JJ |
81 | |
82 | return error; | |
83 | } | |
84 | ||
85 | /** | |
86 | * change_profile_perms - find permissions for change_profile | |
87 | * @profile: the current profile (NOT NULL) | |
88 | * @ns: the namespace being switched to (NOT NULL) | |
89 | * @name: the name of the profile to change to (NOT NULL) | |
90 | * @request: requested perms | |
91 | * @start: state to start matching in | |
92 | * | |
93 | * Returns: permission set | |
94 | */ | |
95 | static struct file_perms change_profile_perms(struct aa_profile *profile, | |
96 | struct aa_namespace *ns, | |
97 | const char *name, u32 request, | |
98 | unsigned int start) | |
99 | { | |
100 | struct file_perms perms; | |
101 | struct path_cond cond = { }; | |
102 | unsigned int state; | |
103 | ||
104 | if (unconfined(profile)) { | |
105 | perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC; | |
106 | perms.audit = perms.quiet = perms.kill = 0; | |
107 | return perms; | |
108 | } else if (!profile->file.dfa) { | |
109 | return nullperms; | |
110 | } else if ((ns == profile->ns)) { | |
111 | /* try matching against rules with out namespace prepended */ | |
112 | aa_str_perms(profile->file.dfa, start, name, &cond, &perms); | |
113 | if (COMBINED_PERM_MASK(perms) & request) | |
114 | return perms; | |
115 | } | |
116 | ||
117 | /* try matching with namespace name and then profile */ | |
118 | state = aa_dfa_match(profile->file.dfa, start, ns->base.name); | |
119 | state = aa_dfa_match_len(profile->file.dfa, state, ":", 1); | |
120 | aa_str_perms(profile->file.dfa, state, name, &cond, &perms); | |
121 | ||
122 | return perms; | |
123 | } | |
124 | ||
125 | /** | |
126 | * __attach_match_ - find an attachment match | |
127 | * @name - to match against (NOT NULL) | |
128 | * @head - profile list to walk (NOT NULL) | |
129 | * | |
130 | * Do a linear search on the profiles in the list. There is a matching | |
131 | * preference where an exact match is preferred over a name which uses | |
132 | * expressions to match, and matching expressions with the greatest | |
133 | * xmatch_len are preferred. | |
134 | * | |
135 | * Requires: @head not be shared or have appropriate locks held | |
136 | * | |
137 | * Returns: profile or NULL if no match found | |
138 | */ | |
139 | static struct aa_profile *__attach_match(const char *name, | |
140 | struct list_head *head) | |
141 | { | |
142 | int len = 0; | |
143 | struct aa_profile *profile, *candidate = NULL; | |
144 | ||
01e2b670 | 145 | list_for_each_entry_rcu(profile, head, base.list) { |
898127c3 JJ |
146 | if (profile->flags & PFLAG_NULL) |
147 | continue; | |
148 | if (profile->xmatch && profile->xmatch_len > len) { | |
149 | unsigned int state = aa_dfa_match(profile->xmatch, | |
150 | DFA_START, name); | |
151 | u32 perm = dfa_user_allow(profile->xmatch, state); | |
152 | /* any accepting state means a valid match. */ | |
153 | if (perm & MAY_EXEC) { | |
154 | candidate = profile; | |
155 | len = profile->xmatch_len; | |
156 | } | |
157 | } else if (!strcmp(profile->base.name, name)) | |
158 | /* exact non-re match, no more searching required */ | |
159 | return profile; | |
160 | } | |
161 | ||
162 | return candidate; | |
163 | } | |
164 | ||
165 | /** | |
166 | * find_attach - do attachment search for unconfined processes | |
167 | * @ns: the current namespace (NOT NULL) | |
168 | * @list: list to search (NOT NULL) | |
169 | * @name: the executable name to match against (NOT NULL) | |
170 | * | |
171 | * Returns: profile or NULL if no match found | |
172 | */ | |
173 | static struct aa_profile *find_attach(struct aa_namespace *ns, | |
174 | struct list_head *list, const char *name) | |
175 | { | |
176 | struct aa_profile *profile; | |
177 | ||
01e2b670 | 178 | rcu_read_lock(); |
898127c3 | 179 | profile = aa_get_profile(__attach_match(name, list)); |
01e2b670 | 180 | rcu_read_unlock(); |
898127c3 JJ |
181 | |
182 | return profile; | |
183 | } | |
184 | ||
185 | /** | |
186 | * separate_fqname - separate the namespace and profile names | |
187 | * @fqname: the fqname name to split (NOT NULL) | |
188 | * @ns_name: the namespace name if it exists (NOT NULL) | |
189 | * | |
190 | * This is the xtable equivalent routine of aa_split_fqname. It finds the | |
191 | * split in an xtable fqname which contains an embedded \0 instead of a : | |
192 | * if a namespace is specified. This is done so the xtable is constant and | |
193 | * isn't re-split on every lookup. | |
194 | * | |
195 | * Either the profile or namespace name may be optional but if the namespace | |
196 | * is specified the profile name termination must be present. This results | |
197 | * in the following possible encodings: | |
198 | * profile_name\0 | |
199 | * :ns_name\0profile_name\0 | |
200 | * :ns_name\0\0 | |
201 | * | |
202 | * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table | |
203 | * | |
204 | * Returns: profile name if it is specified else NULL | |
205 | */ | |
206 | static const char *separate_fqname(const char *fqname, const char **ns_name) | |
207 | { | |
208 | const char *name; | |
209 | ||
210 | if (fqname[0] == ':') { | |
211 | /* In this case there is guaranteed to be two \0 terminators | |
212 | * in the string. They are verified at load time by | |
213 | * by unpack_trans_table | |
214 | */ | |
215 | *ns_name = fqname + 1; /* skip : */ | |
216 | name = *ns_name + strlen(*ns_name) + 1; | |
217 | if (!*name) | |
218 | name = NULL; | |
219 | } else { | |
220 | *ns_name = NULL; | |
221 | name = fqname; | |
222 | } | |
223 | ||
224 | return name; | |
225 | } | |
226 | ||
227 | static const char *next_name(int xtype, const char *name) | |
228 | { | |
229 | return NULL; | |
230 | } | |
231 | ||
232 | /** | |
233 | * x_table_lookup - lookup an x transition name via transition table | |
234 | * @profile: current profile (NOT NULL) | |
235 | * @xindex: index into x transition table | |
236 | * | |
237 | * Returns: refcounted profile, or NULL on failure (MAYBE NULL) | |
238 | */ | |
239 | static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex) | |
240 | { | |
241 | struct aa_profile *new_profile = NULL; | |
242 | struct aa_namespace *ns = profile->ns; | |
243 | u32 xtype = xindex & AA_X_TYPE_MASK; | |
244 | int index = xindex & AA_X_INDEX_MASK; | |
245 | const char *name; | |
246 | ||
247 | /* index is guaranteed to be in range, validated at load time */ | |
248 | for (name = profile->file.trans.table[index]; !new_profile && name; | |
249 | name = next_name(xtype, name)) { | |
250 | struct aa_namespace *new_ns; | |
251 | const char *xname = NULL; | |
252 | ||
253 | new_ns = NULL; | |
254 | if (xindex & AA_X_CHILD) { | |
255 | /* release by caller */ | |
256 | new_profile = aa_find_child(profile, name); | |
257 | continue; | |
258 | } else if (*name == ':') { | |
259 | /* switching namespace */ | |
260 | const char *ns_name; | |
261 | xname = name = separate_fqname(name, &ns_name); | |
262 | if (!xname) | |
263 | /* no name so use profile name */ | |
264 | xname = profile->base.hname; | |
265 | if (*ns_name == '@') { | |
266 | /* TODO: variable support */ | |
267 | ; | |
268 | } | |
269 | /* released below */ | |
270 | new_ns = aa_find_namespace(ns, ns_name); | |
271 | if (!new_ns) | |
272 | continue; | |
273 | } else if (*name == '@') { | |
274 | /* TODO: variable support */ | |
275 | continue; | |
276 | } else { | |
277 | /* basic namespace lookup */ | |
278 | xname = name; | |
279 | } | |
280 | ||
281 | /* released by caller */ | |
282 | new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname); | |
283 | aa_put_namespace(new_ns); | |
284 | } | |
285 | ||
286 | /* released by caller */ | |
287 | return new_profile; | |
288 | } | |
289 | ||
290 | /** | |
291 | * x_to_profile - get target profile for a given xindex | |
292 | * @profile: current profile (NOT NULL) | |
293 | * @name: name to lookup (NOT NULL) | |
294 | * @xindex: index into x transition table | |
295 | * | |
296 | * find profile for a transition index | |
297 | * | |
298 | * Returns: refcounted profile or NULL if not found available | |
299 | */ | |
300 | static struct aa_profile *x_to_profile(struct aa_profile *profile, | |
301 | const char *name, u32 xindex) | |
302 | { | |
303 | struct aa_profile *new_profile = NULL; | |
304 | struct aa_namespace *ns = profile->ns; | |
305 | u32 xtype = xindex & AA_X_TYPE_MASK; | |
306 | ||
307 | switch (xtype) { | |
308 | case AA_X_NONE: | |
309 | /* fail exec unless ix || ux fallback - handled by caller */ | |
310 | return NULL; | |
311 | case AA_X_NAME: | |
312 | if (xindex & AA_X_CHILD) | |
313 | /* released by caller */ | |
314 | new_profile = find_attach(ns, &profile->base.profiles, | |
315 | name); | |
316 | else | |
317 | /* released by caller */ | |
318 | new_profile = find_attach(ns, &ns->base.profiles, | |
319 | name); | |
320 | break; | |
321 | case AA_X_TABLE: | |
322 | /* released by caller */ | |
323 | new_profile = x_table_lookup(profile, xindex); | |
324 | break; | |
325 | } | |
326 | ||
327 | /* released by caller */ | |
328 | return new_profile; | |
329 | } | |
330 | ||
331 | /** | |
332 | * apparmor_bprm_set_creds - set the new creds on the bprm struct | |
333 | * @bprm: binprm for the exec (NOT NULL) | |
334 | * | |
335 | * Returns: %0 or error on failure | |
336 | */ | |
337 | int apparmor_bprm_set_creds(struct linux_binprm *bprm) | |
338 | { | |
339 | struct aa_task_cxt *cxt; | |
340 | struct aa_profile *profile, *new_profile = NULL; | |
341 | struct aa_namespace *ns; | |
342 | char *buffer = NULL; | |
343 | unsigned int state; | |
344 | struct file_perms perms = {}; | |
345 | struct path_cond cond = { | |
496ad9aa AV |
346 | file_inode(bprm->file)->i_uid, |
347 | file_inode(bprm->file)->i_mode | |
898127c3 JJ |
348 | }; |
349 | const char *name = NULL, *target = NULL, *info = NULL; | |
b1d9e6b0 | 350 | int error = 0; |
898127c3 JJ |
351 | |
352 | if (bprm->cred_prepared) | |
353 | return 0; | |
354 | ||
214beaca | 355 | cxt = cred_cxt(bprm->cred); |
898127c3 JJ |
356 | BUG_ON(!cxt); |
357 | ||
77b071b3 | 358 | profile = aa_get_newest_profile(cxt->profile); |
898127c3 JJ |
359 | /* |
360 | * get the namespace from the replacement profile as replacement | |
361 | * can change the namespace | |
362 | */ | |
363 | ns = profile->ns; | |
364 | state = profile->file.start; | |
365 | ||
366 | /* buffer freed below, name is pointer into buffer */ | |
57fa1e18 JJ |
367 | error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer, |
368 | &name, &info); | |
898127c3 | 369 | if (error) { |
03816507 JJ |
370 | if (unconfined(profile) || |
371 | (profile->flags & PFLAG_IX_ON_NAME_ERROR)) | |
898127c3 | 372 | error = 0; |
898127c3 JJ |
373 | name = bprm->filename; |
374 | goto audit; | |
375 | } | |
376 | ||
377 | /* Test for onexec first as onexec directives override other | |
378 | * x transitions. | |
379 | */ | |
380 | if (unconfined(profile)) { | |
381 | /* unconfined task */ | |
382 | if (cxt->onexec) | |
383 | /* change_profile on exec already been granted */ | |
384 | new_profile = aa_get_profile(cxt->onexec); | |
385 | else | |
386 | new_profile = find_attach(ns, &ns->base.profiles, name); | |
387 | if (!new_profile) | |
388 | goto cleanup; | |
c29bceb3 JJ |
389 | /* |
390 | * NOTE: Domain transitions from unconfined are allowed | |
391 | * even when no_new_privs is set because this aways results | |
392 | * in a further reduction of permissions. | |
393 | */ | |
898127c3 JJ |
394 | goto apply; |
395 | } | |
396 | ||
397 | /* find exec permissions for name */ | |
398 | state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms); | |
399 | if (cxt->onexec) { | |
400 | struct file_perms cp; | |
401 | info = "change_profile onexec"; | |
402 | if (!(perms.allow & AA_MAY_ONEXEC)) | |
403 | goto audit; | |
404 | ||
405 | /* test if this exec can be paired with change_profile onexec. | |
406 | * onexec permission is linked to exec with a standard pairing | |
407 | * exec\0change_profile | |
408 | */ | |
409 | state = aa_dfa_null_transition(profile->file.dfa, state); | |
0421ea91 JJ |
410 | cp = change_profile_perms(profile, cxt->onexec->ns, |
411 | cxt->onexec->base.name, | |
898127c3 JJ |
412 | AA_MAY_ONEXEC, state); |
413 | ||
414 | if (!(cp.allow & AA_MAY_ONEXEC)) | |
415 | goto audit; | |
77b071b3 | 416 | new_profile = aa_get_newest_profile(cxt->onexec); |
898127c3 JJ |
417 | goto apply; |
418 | } | |
419 | ||
420 | if (perms.allow & MAY_EXEC) { | |
421 | /* exec permission determine how to transition */ | |
422 | new_profile = x_to_profile(profile, name, perms.xindex); | |
423 | if (!new_profile) { | |
424 | if (perms.xindex & AA_X_INHERIT) { | |
425 | /* (p|c|n)ix - don't change profile but do | |
426 | * use the newest version, which was picked | |
427 | * up above when getting profile | |
428 | */ | |
429 | info = "ix fallback"; | |
430 | new_profile = aa_get_profile(profile); | |
431 | goto x_clear; | |
432 | } else if (perms.xindex & AA_X_UNCONFINED) { | |
fa2ac468 | 433 | new_profile = aa_get_newest_profile(ns->unconfined); |
898127c3 JJ |
434 | info = "ux fallback"; |
435 | } else { | |
436 | error = -ENOENT; | |
437 | info = "profile not found"; | |
17322cc3 JJ |
438 | /* remove MAY_EXEC to audit as failure */ |
439 | perms.allow &= ~MAY_EXEC; | |
898127c3 JJ |
440 | } |
441 | } | |
442 | } else if (COMPLAIN_MODE(profile)) { | |
443 | /* no exec permission - are we in learning mode */ | |
444 | new_profile = aa_new_null_profile(profile, 0); | |
445 | if (!new_profile) { | |
446 | error = -ENOMEM; | |
447 | info = "could not create null profile"; | |
448 | } else { | |
449 | error = -EACCES; | |
450 | target = new_profile->base.hname; | |
451 | } | |
452 | perms.xindex |= AA_X_UNSAFE; | |
453 | } else | |
454 | /* fail exec */ | |
455 | error = -EACCES; | |
456 | ||
c29bceb3 JJ |
457 | /* |
458 | * Policy has specified a domain transition, if no_new_privs then | |
459 | * fail the exec. | |
460 | */ | |
461 | if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) { | |
462 | aa_put_profile(new_profile); | |
463 | error = -EPERM; | |
464 | goto cleanup; | |
465 | } | |
466 | ||
898127c3 JJ |
467 | if (!new_profile) |
468 | goto audit; | |
469 | ||
470 | if (bprm->unsafe & LSM_UNSAFE_SHARE) { | |
471 | /* FIXME: currently don't mediate shared state */ | |
472 | ; | |
473 | } | |
474 | ||
475 | if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { | |
51775fe7 | 476 | error = may_change_ptraced_domain(new_profile); |
898127c3 JJ |
477 | if (error) { |
478 | aa_put_profile(new_profile); | |
479 | goto audit; | |
480 | } | |
481 | } | |
482 | ||
483 | /* Determine if secure exec is needed. | |
484 | * Can be at this point for the following reasons: | |
485 | * 1. unconfined switching to confined | |
486 | * 2. confined switching to different confinement | |
487 | * 3. confined switching to unconfined | |
488 | * | |
489 | * Cases 2 and 3 are marked as requiring secure exec | |
490 | * (unless policy specified "unsafe exec") | |
491 | * | |
492 | * bprm->unsafe is used to cache the AA_X_UNSAFE permission | |
493 | * to avoid having to recompute in secureexec | |
494 | */ | |
495 | if (!(perms.xindex & AA_X_UNSAFE)) { | |
496 | AA_DEBUG("scrubbing environment variables for %s profile=%s\n", | |
497 | name, new_profile->base.hname); | |
498 | bprm->unsafe |= AA_SECURE_X_NEEDED; | |
499 | } | |
500 | apply: | |
501 | target = new_profile->base.hname; | |
502 | /* when transitioning profiles clear unsafe personality bits */ | |
503 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
504 | ||
505 | x_clear: | |
506 | aa_put_profile(cxt->profile); | |
507 | /* transfer new profile reference will be released when cxt is freed */ | |
508 | cxt->profile = new_profile; | |
509 | ||
510 | /* clear out all temporary/transitional state from the context */ | |
7a2871b5 | 511 | aa_clear_task_cxt_trans(cxt); |
898127c3 JJ |
512 | |
513 | audit: | |
514 | error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC, | |
515 | name, target, cond.uid, info, error); | |
516 | ||
517 | cleanup: | |
518 | aa_put_profile(profile); | |
519 | kfree(buffer); | |
520 | ||
521 | return error; | |
522 | } | |
523 | ||
524 | /** | |
525 | * apparmor_bprm_secureexec - determine if secureexec is needed | |
526 | * @bprm: binprm for exec (NOT NULL) | |
527 | * | |
528 | * Returns: %1 if secureexec is needed else %0 | |
529 | */ | |
530 | int apparmor_bprm_secureexec(struct linux_binprm *bprm) | |
531 | { | |
898127c3 JJ |
532 | /* the decision to use secure exec is computed in set_creds |
533 | * and stored in bprm->unsafe. | |
534 | */ | |
b1d9e6b0 CS |
535 | if (bprm->unsafe & AA_SECURE_X_NEEDED) |
536 | return 1; | |
898127c3 | 537 | |
b1d9e6b0 | 538 | return 0; |
898127c3 JJ |
539 | } |
540 | ||
541 | /** | |
542 | * apparmor_bprm_committing_creds - do task cleanup on committing new creds | |
543 | * @bprm: binprm for the exec (NOT NULL) | |
544 | */ | |
545 | void apparmor_bprm_committing_creds(struct linux_binprm *bprm) | |
546 | { | |
547 | struct aa_profile *profile = __aa_current_profile(); | |
214beaca | 548 | struct aa_task_cxt *new_cxt = cred_cxt(bprm->cred); |
898127c3 JJ |
549 | |
550 | /* bail out if unconfined or not changing profile */ | |
551 | if ((new_cxt->profile == profile) || | |
552 | (unconfined(new_cxt->profile))) | |
553 | return; | |
554 | ||
555 | current->pdeath_signal = 0; | |
556 | ||
557 | /* reset soft limits and set hard limits for the new profile */ | |
558 | __aa_transition_rlimits(profile, new_cxt->profile); | |
559 | } | |
560 | ||
561 | /** | |
562 | * apparmor_bprm_commited_cred - do cleanup after new creds committed | |
563 | * @bprm: binprm for the exec (NOT NULL) | |
564 | */ | |
565 | void apparmor_bprm_committed_creds(struct linux_binprm *bprm) | |
566 | { | |
567 | /* TODO: cleanup signals - ipc mediation */ | |
568 | return; | |
569 | } | |
570 | ||
571 | /* | |
572 | * Functions for self directed profile change | |
573 | */ | |
574 | ||
575 | /** | |
576 | * new_compound_name - create an hname with @n2 appended to @n1 | |
577 | * @n1: base of hname (NOT NULL) | |
578 | * @n2: name to append (NOT NULL) | |
579 | * | |
580 | * Returns: new name or NULL on error | |
581 | */ | |
582 | static char *new_compound_name(const char *n1, const char *n2) | |
583 | { | |
584 | char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL); | |
585 | if (name) | |
586 | sprintf(name, "%s//%s", n1, n2); | |
587 | return name; | |
588 | } | |
589 | ||
590 | /** | |
591 | * aa_change_hat - change hat to/from subprofile | |
592 | * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0) | |
593 | * @count: number of hat names in @hats | |
594 | * @token: magic value to validate the hat change | |
595 | * @permtest: true if this is just a permission test | |
596 | * | |
597 | * Change to the first profile specified in @hats that exists, and store | |
598 | * the @hat_magic in the current task context. If the count == 0 and the | |
599 | * @token matches that stored in the current task context, return to the | |
600 | * top level profile. | |
601 | * | |
602 | * Returns %0 on success, error otherwise. | |
603 | */ | |
604 | int aa_change_hat(const char *hats[], int count, u64 token, bool permtest) | |
605 | { | |
606 | const struct cred *cred; | |
607 | struct aa_task_cxt *cxt; | |
608 | struct aa_profile *profile, *previous_profile, *hat = NULL; | |
609 | char *name = NULL; | |
610 | int i; | |
611 | struct file_perms perms = {}; | |
612 | const char *target = NULL, *info = NULL; | |
613 | int error = 0; | |
614 | ||
c29bceb3 JJ |
615 | /* |
616 | * Fail explicitly requested domain transitions if no_new_privs. | |
617 | * There is no exception for unconfined as change_hat is not | |
618 | * available. | |
619 | */ | |
1d4457f9 | 620 | if (task_no_new_privs(current)) |
c29bceb3 JJ |
621 | return -EPERM; |
622 | ||
898127c3 JJ |
623 | /* released below */ |
624 | cred = get_current_cred(); | |
214beaca | 625 | cxt = cred_cxt(cred); |
898127c3 JJ |
626 | profile = aa_cred_profile(cred); |
627 | previous_profile = cxt->previous; | |
628 | ||
629 | if (unconfined(profile)) { | |
630 | info = "unconfined"; | |
631 | error = -EPERM; | |
632 | goto audit; | |
633 | } | |
634 | ||
635 | if (count) { | |
636 | /* attempting to change into a new hat or switch to a sibling */ | |
637 | struct aa_profile *root; | |
01e2b670 JJ |
638 | if (PROFILE_IS_HAT(profile)) |
639 | root = aa_get_profile_rcu(&profile->parent); | |
640 | else | |
641 | root = aa_get_profile(profile); | |
898127c3 JJ |
642 | |
643 | /* find first matching hat */ | |
644 | for (i = 0; i < count && !hat; i++) | |
645 | /* released below */ | |
646 | hat = aa_find_child(root, hats[i]); | |
647 | if (!hat) { | |
648 | if (!COMPLAIN_MODE(root) || permtest) { | |
649 | if (list_empty(&root->base.profiles)) | |
650 | error = -ECHILD; | |
651 | else | |
652 | error = -ENOENT; | |
01e2b670 | 653 | aa_put_profile(root); |
898127c3 JJ |
654 | goto out; |
655 | } | |
656 | ||
657 | /* | |
658 | * In complain mode and failed to match any hats. | |
659 | * Audit the failure is based off of the first hat | |
660 | * supplied. This is done due how userspace | |
661 | * interacts with change_hat. | |
662 | * | |
663 | * TODO: Add logging of all failed hats | |
664 | */ | |
665 | ||
666 | /* freed below */ | |
667 | name = new_compound_name(root->base.hname, hats[0]); | |
01e2b670 | 668 | aa_put_profile(root); |
898127c3 JJ |
669 | target = name; |
670 | /* released below */ | |
671 | hat = aa_new_null_profile(profile, 1); | |
672 | if (!hat) { | |
673 | info = "failed null profile create"; | |
674 | error = -ENOMEM; | |
675 | goto audit; | |
676 | } | |
677 | } else { | |
01e2b670 | 678 | aa_put_profile(root); |
898127c3 JJ |
679 | target = hat->base.hname; |
680 | if (!PROFILE_IS_HAT(hat)) { | |
681 | info = "target not hat"; | |
682 | error = -EPERM; | |
683 | goto audit; | |
684 | } | |
685 | } | |
686 | ||
51775fe7 | 687 | error = may_change_ptraced_domain(hat); |
898127c3 JJ |
688 | if (error) { |
689 | info = "ptraced"; | |
690 | error = -EPERM; | |
691 | goto audit; | |
692 | } | |
693 | ||
694 | if (!permtest) { | |
695 | error = aa_set_current_hat(hat, token); | |
696 | if (error == -EACCES) | |
697 | /* kill task in case of brute force attacks */ | |
698 | perms.kill = AA_MAY_CHANGEHAT; | |
699 | else if (name && !error) | |
700 | /* reset error for learning of new hats */ | |
701 | error = -ENOENT; | |
702 | } | |
703 | } else if (previous_profile) { | |
704 | /* Return to saved profile. Kill task if restore fails | |
705 | * to avoid brute force attacks | |
706 | */ | |
707 | target = previous_profile->base.hname; | |
708 | error = aa_restore_previous_profile(token); | |
709 | perms.kill = AA_MAY_CHANGEHAT; | |
710 | } else | |
711 | /* ignore restores when there is no saved profile */ | |
712 | goto out; | |
713 | ||
714 | audit: | |
715 | if (!permtest) | |
716 | error = aa_audit_file(profile, &perms, GFP_KERNEL, | |
717 | OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL, | |
2db81452 | 718 | target, GLOBAL_ROOT_UID, info, error); |
898127c3 JJ |
719 | |
720 | out: | |
721 | aa_put_profile(hat); | |
722 | kfree(name); | |
723 | put_cred(cred); | |
724 | ||
725 | return error; | |
726 | } | |
727 | ||
728 | /** | |
729 | * aa_change_profile - perform a one-way profile transition | |
730 | * @ns_name: name of the profile namespace to change to (MAYBE NULL) | |
731 | * @hname: name of profile to change to (MAYBE NULL) | |
732 | * @onexec: whether this transition is to take place immediately or at exec | |
733 | * @permtest: true if this is just a permission test | |
734 | * | |
735 | * Change to new profile @name. Unlike with hats, there is no way | |
736 | * to change back. If @name isn't specified the current profile name is | |
737 | * used. | |
738 | * If @onexec then the transition is delayed until | |
739 | * the next exec. | |
740 | * | |
741 | * Returns %0 on success, error otherwise. | |
742 | */ | |
743 | int aa_change_profile(const char *ns_name, const char *hname, bool onexec, | |
744 | bool permtest) | |
745 | { | |
746 | const struct cred *cred; | |
898127c3 JJ |
747 | struct aa_profile *profile, *target = NULL; |
748 | struct aa_namespace *ns = NULL; | |
749 | struct file_perms perms = {}; | |
750 | const char *name = NULL, *info = NULL; | |
751 | int op, error = 0; | |
752 | u32 request; | |
753 | ||
754 | if (!hname && !ns_name) | |
755 | return -EINVAL; | |
756 | ||
757 | if (onexec) { | |
758 | request = AA_MAY_ONEXEC; | |
759 | op = OP_CHANGE_ONEXEC; | |
760 | } else { | |
761 | request = AA_MAY_CHANGE_PROFILE; | |
762 | op = OP_CHANGE_PROFILE; | |
763 | } | |
764 | ||
765 | cred = get_current_cred(); | |
898127c3 JJ |
766 | profile = aa_cred_profile(cred); |
767 | ||
c29bceb3 JJ |
768 | /* |
769 | * Fail explicitly requested domain transitions if no_new_privs | |
770 | * and not unconfined. | |
771 | * Domain transitions from unconfined are allowed even when | |
772 | * no_new_privs is set because this aways results in a reduction | |
773 | * of permissions. | |
774 | */ | |
1d4457f9 | 775 | if (task_no_new_privs(current) && !unconfined(profile)) { |
c29bceb3 JJ |
776 | put_cred(cred); |
777 | return -EPERM; | |
778 | } | |
779 | ||
898127c3 JJ |
780 | if (ns_name) { |
781 | /* released below */ | |
782 | ns = aa_find_namespace(profile->ns, ns_name); | |
783 | if (!ns) { | |
784 | /* we don't create new namespace in complain mode */ | |
785 | name = ns_name; | |
786 | info = "namespace not found"; | |
787 | error = -ENOENT; | |
788 | goto audit; | |
789 | } | |
790 | } else | |
791 | /* released below */ | |
792 | ns = aa_get_namespace(profile->ns); | |
793 | ||
794 | /* if the name was not specified, use the name of the current profile */ | |
795 | if (!hname) { | |
796 | if (unconfined(profile)) | |
797 | hname = ns->unconfined->base.hname; | |
798 | else | |
799 | hname = profile->base.hname; | |
800 | } | |
801 | ||
802 | perms = change_profile_perms(profile, ns, hname, request, | |
803 | profile->file.start); | |
804 | if (!(perms.allow & request)) { | |
805 | error = -EACCES; | |
806 | goto audit; | |
807 | } | |
808 | ||
809 | /* released below */ | |
810 | target = aa_lookup_profile(ns, hname); | |
811 | if (!target) { | |
812 | info = "profile not found"; | |
813 | error = -ENOENT; | |
814 | if (permtest || !COMPLAIN_MODE(profile)) | |
815 | goto audit; | |
816 | /* released below */ | |
817 | target = aa_new_null_profile(profile, 0); | |
818 | if (!target) { | |
819 | info = "failed null profile create"; | |
820 | error = -ENOMEM; | |
821 | goto audit; | |
822 | } | |
823 | } | |
824 | ||
825 | /* check if tracing task is allowed to trace target domain */ | |
51775fe7 | 826 | error = may_change_ptraced_domain(target); |
898127c3 JJ |
827 | if (error) { |
828 | info = "ptrace prevents transition"; | |
829 | goto audit; | |
830 | } | |
831 | ||
832 | if (permtest) | |
833 | goto audit; | |
834 | ||
835 | if (onexec) | |
836 | error = aa_set_current_onexec(target); | |
837 | else | |
838 | error = aa_replace_current_profile(target); | |
839 | ||
840 | audit: | |
841 | if (!permtest) | |
842 | error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request, | |
2db81452 | 843 | name, hname, GLOBAL_ROOT_UID, info, error); |
898127c3 JJ |
844 | |
845 | aa_put_namespace(ns); | |
846 | aa_put_profile(target); | |
847 | put_cred(cred); | |
848 | ||
849 | return error; | |
850 | } |