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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 |
53 | * @to_profile: profile to change to (NOT NULL) |
54 | * |
55 | * Check if current is ptraced and if so if the tracing task is allowed |
56 | * to trace the new domain |
57 | * |
58 | * Returns: %0 or error if change not allowed |
59 | */ |
60 | static int may_change_ptraced_domain(struct aa_profile *to_profile) |
61 | { |
62 | struct task_struct *tracer; |
63 | struct aa_profile *tracerp = NULL; |
64 | int error = 0; |
65 | |
66 | rcu_read_lock(); |
67 | tracer = ptrace_parent(current); |
68 | if (tracer) |
69 | /* released below */ |
70 | tracerp = aa_get_task_profile(tracer); |
71 | |
72 | /* not ptraced */ |
73 | if (!tracer || unconfined(tracerp)) |
74 | goto out; |
75 | |
76 | error = aa_may_ptrace(tracerp, to_profile, PTRACE_MODE_ATTACH); |
77 | |
78 | out: |
79 | rcu_read_unlock(); |
80 | aa_put_profile(tracerp); |
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 | |
145 | list_for_each_entry_rcu(profile, head, base.list) { |
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 | |
178 | rcu_read_lock(); |
179 | profile = aa_get_profile(__attach_match(name, list)); |
180 | rcu_read_unlock(); |
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 = { |
346 | file_inode(bprm->file)->i_uid, |
347 | file_inode(bprm->file)->i_mode |
348 | }; |
349 | const char *name = NULL, *target = NULL, *info = NULL; |
350 | int error = cap_bprm_set_creds(bprm); |
351 | if (error) |
352 | return error; |
353 | |
354 | if (bprm->cred_prepared) |
355 | return 0; |
356 | |
357 | cxt = cred_cxt(bprm->cred); |
358 | BUG_ON(!cxt); |
359 | |
360 | profile = aa_get_newest_profile(cxt->profile); |
361 | /* |
362 | * get the namespace from the replacement profile as replacement |
363 | * can change the namespace |
364 | */ |
365 | ns = profile->ns; |
366 | state = profile->file.start; |
367 | |
368 | /* buffer freed below, name is pointer into buffer */ |
369 | error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer, |
370 | &name, &info); |
371 | if (error) { |
372 | if (unconfined(profile) || |
373 | (profile->flags & PFLAG_IX_ON_NAME_ERROR)) |
374 | error = 0; |
375 | name = bprm->filename; |
376 | goto audit; |
377 | } |
378 | |
379 | /* Test for onexec first as onexec directives override other |
380 | * x transitions. |
381 | */ |
382 | if (unconfined(profile)) { |
383 | /* unconfined task */ |
384 | if (cxt->onexec) |
385 | /* change_profile on exec already been granted */ |
386 | new_profile = aa_get_profile(cxt->onexec); |
387 | else |
388 | new_profile = find_attach(ns, &ns->base.profiles, name); |
389 | if (!new_profile) |
390 | goto cleanup; |
391 | /* |
392 | * NOTE: Domain transitions from unconfined are allowed |
393 | * even when no_new_privs is set because this aways results |
394 | * in a further reduction of permissions. |
395 | */ |
396 | goto apply; |
397 | } |
398 | |
399 | /* find exec permissions for name */ |
400 | state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms); |
401 | if (cxt->onexec) { |
402 | struct file_perms cp; |
403 | info = "change_profile onexec"; |
404 | if (!(perms.allow & AA_MAY_ONEXEC)) |
405 | goto audit; |
406 | |
407 | /* test if this exec can be paired with change_profile onexec. |
408 | * onexec permission is linked to exec with a standard pairing |
409 | * exec\0change_profile |
410 | */ |
411 | state = aa_dfa_null_transition(profile->file.dfa, state); |
412 | cp = change_profile_perms(profile, cxt->onexec->ns, |
413 | cxt->onexec->base.name, |
414 | AA_MAY_ONEXEC, state); |
415 | |
416 | if (!(cp.allow & AA_MAY_ONEXEC)) |
417 | goto audit; |
418 | new_profile = aa_get_newest_profile(cxt->onexec); |
419 | goto apply; |
420 | } |
421 | |
422 | if (perms.allow & MAY_EXEC) { |
423 | /* exec permission determine how to transition */ |
424 | new_profile = x_to_profile(profile, name, perms.xindex); |
425 | if (!new_profile) { |
426 | if (perms.xindex & AA_X_INHERIT) { |
427 | /* (p|c|n)ix - don't change profile but do |
428 | * use the newest version, which was picked |
429 | * up above when getting profile |
430 | */ |
431 | info = "ix fallback"; |
432 | new_profile = aa_get_profile(profile); |
433 | goto x_clear; |
434 | } else if (perms.xindex & AA_X_UNCONFINED) { |
435 | new_profile = aa_get_newest_profile(ns->unconfined); |
436 | info = "ux fallback"; |
437 | } else { |
438 | error = -ENOENT; |
439 | info = "profile not found"; |
440 | /* remove MAY_EXEC to audit as failure */ |
441 | perms.allow &= ~MAY_EXEC; |
442 | } |
443 | } |
444 | } else if (COMPLAIN_MODE(profile)) { |
445 | /* no exec permission - are we in learning mode */ |
446 | new_profile = aa_new_null_profile(profile, 0); |
447 | if (!new_profile) { |
448 | error = -ENOMEM; |
449 | info = "could not create null profile"; |
450 | } else { |
451 | error = -EACCES; |
452 | target = new_profile->base.hname; |
453 | } |
454 | perms.xindex |= AA_X_UNSAFE; |
455 | } else |
456 | /* fail exec */ |
457 | error = -EACCES; |
458 | |
459 | /* |
460 | * Policy has specified a domain transition, if no_new_privs then |
461 | * fail the exec. |
462 | */ |
463 | if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) { |
464 | aa_put_profile(new_profile); |
465 | error = -EPERM; |
466 | goto cleanup; |
467 | } |
468 | |
469 | if (!new_profile) |
470 | goto audit; |
471 | |
472 | if (bprm->unsafe & LSM_UNSAFE_SHARE) { |
473 | /* FIXME: currently don't mediate shared state */ |
474 | ; |
475 | } |
476 | |
477 | if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { |
478 | error = may_change_ptraced_domain(new_profile); |
479 | if (error) { |
480 | aa_put_profile(new_profile); |
481 | goto audit; |
482 | } |
483 | } |
484 | |
485 | /* Determine if secure exec is needed. |
486 | * Can be at this point for the following reasons: |
487 | * 1. unconfined switching to confined |
488 | * 2. confined switching to different confinement |
489 | * 3. confined switching to unconfined |
490 | * |
491 | * Cases 2 and 3 are marked as requiring secure exec |
492 | * (unless policy specified "unsafe exec") |
493 | * |
494 | * bprm->unsafe is used to cache the AA_X_UNSAFE permission |
495 | * to avoid having to recompute in secureexec |
496 | */ |
497 | if (!(perms.xindex & AA_X_UNSAFE)) { |
498 | AA_DEBUG("scrubbing environment variables for %s profile=%s\n", |
499 | name, new_profile->base.hname); |
500 | bprm->unsafe |= AA_SECURE_X_NEEDED; |
501 | } |
502 | apply: |
503 | target = new_profile->base.hname; |
504 | /* when transitioning profiles clear unsafe personality bits */ |
505 | bprm->per_clear |= PER_CLEAR_ON_SETID; |
506 | |
507 | x_clear: |
508 | aa_put_profile(cxt->profile); |
509 | /* transfer new profile reference will be released when cxt is freed */ |
510 | cxt->profile = new_profile; |
511 | |
512 | /* clear out all temporary/transitional state from the context */ |
513 | aa_clear_task_cxt_trans(cxt); |
514 | |
515 | audit: |
516 | error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC, |
517 | name, target, cond.uid, info, error); |
518 | |
519 | cleanup: |
520 | aa_put_profile(profile); |
521 | kfree(buffer); |
522 | |
523 | return error; |
524 | } |
525 | |
526 | /** |
527 | * apparmor_bprm_secureexec - determine if secureexec is needed |
528 | * @bprm: binprm for exec (NOT NULL) |
529 | * |
530 | * Returns: %1 if secureexec is needed else %0 |
531 | */ |
532 | int apparmor_bprm_secureexec(struct linux_binprm *bprm) |
533 | { |
534 | int ret = cap_bprm_secureexec(bprm); |
535 | |
536 | /* the decision to use secure exec is computed in set_creds |
537 | * and stored in bprm->unsafe. |
538 | */ |
539 | if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED)) |
540 | ret = 1; |
541 | |
542 | return ret; |
543 | } |
544 | |
545 | /** |
546 | * apparmor_bprm_committing_creds - do task cleanup on committing new creds |
547 | * @bprm: binprm for the exec (NOT NULL) |
548 | */ |
549 | void apparmor_bprm_committing_creds(struct linux_binprm *bprm) |
550 | { |
551 | struct aa_profile *profile = __aa_current_profile(); |
552 | struct aa_task_cxt *new_cxt = cred_cxt(bprm->cred); |
553 | |
554 | /* bail out if unconfined or not changing profile */ |
555 | if ((new_cxt->profile == profile) || |
556 | (unconfined(new_cxt->profile))) |
557 | return; |
558 | |
559 | current->pdeath_signal = 0; |
560 | |
561 | /* reset soft limits and set hard limits for the new profile */ |
562 | __aa_transition_rlimits(profile, new_cxt->profile); |
563 | } |
564 | |
565 | /** |
566 | * apparmor_bprm_commited_cred - do cleanup after new creds committed |
567 | * @bprm: binprm for the exec (NOT NULL) |
568 | */ |
569 | void apparmor_bprm_committed_creds(struct linux_binprm *bprm) |
570 | { |
571 | /* TODO: cleanup signals - ipc mediation */ |
572 | return; |
573 | } |
574 | |
575 | /* |
576 | * Functions for self directed profile change |
577 | */ |
578 | |
579 | /** |
580 | * new_compound_name - create an hname with @n2 appended to @n1 |
581 | * @n1: base of hname (NOT NULL) |
582 | * @n2: name to append (NOT NULL) |
583 | * |
584 | * Returns: new name or NULL on error |
585 | */ |
586 | static char *new_compound_name(const char *n1, const char *n2) |
587 | { |
588 | char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL); |
589 | if (name) |
590 | sprintf(name, "%s//%s", n1, n2); |
591 | return name; |
592 | } |
593 | |
594 | /** |
595 | * aa_change_hat - change hat to/from subprofile |
596 | * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0) |
597 | * @count: number of hat names in @hats |
598 | * @token: magic value to validate the hat change |
599 | * @permtest: true if this is just a permission test |
600 | * |
601 | * Change to the first profile specified in @hats that exists, and store |
602 | * the @hat_magic in the current task context. If the count == 0 and the |
603 | * @token matches that stored in the current task context, return to the |
604 | * top level profile. |
605 | * |
606 | * Returns %0 on success, error otherwise. |
607 | */ |
608 | int aa_change_hat(const char *hats[], int count, u64 token, bool permtest) |
609 | { |
610 | const struct cred *cred; |
611 | struct aa_task_cxt *cxt; |
612 | struct aa_profile *profile, *previous_profile, *hat = NULL; |
613 | char *name = NULL; |
614 | int i; |
615 | struct file_perms perms = {}; |
616 | const char *target = NULL, *info = NULL; |
617 | int error = 0; |
618 | |
619 | /* |
620 | * Fail explicitly requested domain transitions if no_new_privs. |
621 | * There is no exception for unconfined as change_hat is not |
622 | * available. |
623 | */ |
624 | if (current->no_new_privs) |
625 | return -EPERM; |
626 | |
627 | /* released below */ |
628 | cred = get_current_cred(); |
629 | cxt = cred_cxt(cred); |
630 | profile = aa_cred_profile(cred); |
631 | previous_profile = cxt->previous; |
632 | |
633 | if (unconfined(profile)) { |
634 | info = "unconfined"; |
635 | error = -EPERM; |
636 | goto audit; |
637 | } |
638 | |
639 | if (count) { |
640 | /* attempting to change into a new hat or switch to a sibling */ |
641 | struct aa_profile *root; |
642 | if (PROFILE_IS_HAT(profile)) |
643 | root = aa_get_profile_rcu(&profile->parent); |
644 | else |
645 | root = aa_get_profile(profile); |
646 | |
647 | /* find first matching hat */ |
648 | for (i = 0; i < count && !hat; i++) |
649 | /* released below */ |
650 | hat = aa_find_child(root, hats[i]); |
651 | if (!hat) { |
652 | if (!COMPLAIN_MODE(root) || permtest) { |
653 | if (list_empty(&root->base.profiles)) |
654 | error = -ECHILD; |
655 | else |
656 | error = -ENOENT; |
657 | aa_put_profile(root); |
658 | goto out; |
659 | } |
660 | |
661 | /* |
662 | * In complain mode and failed to match any hats. |
663 | * Audit the failure is based off of the first hat |
664 | * supplied. This is done due how userspace |
665 | * interacts with change_hat. |
666 | * |
667 | * TODO: Add logging of all failed hats |
668 | */ |
669 | |
670 | /* freed below */ |
671 | name = new_compound_name(root->base.hname, hats[0]); |
672 | aa_put_profile(root); |
673 | target = name; |
674 | /* released below */ |
675 | hat = aa_new_null_profile(profile, 1); |
676 | if (!hat) { |
677 | info = "failed null profile create"; |
678 | error = -ENOMEM; |
679 | goto audit; |
680 | } |
681 | } else { |
682 | aa_put_profile(root); |
683 | target = hat->base.hname; |
684 | if (!PROFILE_IS_HAT(hat)) { |
685 | info = "target not hat"; |
686 | error = -EPERM; |
687 | goto audit; |
688 | } |
689 | } |
690 | |
691 | error = may_change_ptraced_domain(hat); |
692 | if (error) { |
693 | info = "ptraced"; |
694 | error = -EPERM; |
695 | goto audit; |
696 | } |
697 | |
698 | if (!permtest) { |
699 | error = aa_set_current_hat(hat, token); |
700 | if (error == -EACCES) |
701 | /* kill task in case of brute force attacks */ |
702 | perms.kill = AA_MAY_CHANGEHAT; |
703 | else if (name && !error) |
704 | /* reset error for learning of new hats */ |
705 | error = -ENOENT; |
706 | } |
707 | } else if (previous_profile) { |
708 | /* Return to saved profile. Kill task if restore fails |
709 | * to avoid brute force attacks |
710 | */ |
711 | target = previous_profile->base.hname; |
712 | error = aa_restore_previous_profile(token); |
713 | perms.kill = AA_MAY_CHANGEHAT; |
714 | } else |
715 | /* ignore restores when there is no saved profile */ |
716 | goto out; |
717 | |
718 | audit: |
719 | if (!permtest) |
720 | error = aa_audit_file(profile, &perms, GFP_KERNEL, |
721 | OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL, |
722 | target, GLOBAL_ROOT_UID, info, error); |
723 | |
724 | out: |
725 | aa_put_profile(hat); |
726 | kfree(name); |
727 | put_cred(cred); |
728 | |
729 | return error; |
730 | } |
731 | |
732 | /** |
733 | * aa_change_profile - perform a one-way profile transition |
734 | * @ns_name: name of the profile namespace to change to (MAYBE NULL) |
735 | * @hname: name of profile to change to (MAYBE NULL) |
736 | * @onexec: whether this transition is to take place immediately or at exec |
737 | * @permtest: true if this is just a permission test |
738 | * |
739 | * Change to new profile @name. Unlike with hats, there is no way |
740 | * to change back. If @name isn't specified the current profile name is |
741 | * used. |
742 | * If @onexec then the transition is delayed until |
743 | * the next exec. |
744 | * |
745 | * Returns %0 on success, error otherwise. |
746 | */ |
747 | int aa_change_profile(const char *ns_name, const char *hname, bool onexec, |
748 | bool permtest) |
749 | { |
750 | const struct cred *cred; |
751 | struct aa_profile *profile, *target = NULL; |
752 | struct aa_namespace *ns = NULL; |
753 | struct file_perms perms = {}; |
754 | const char *name = NULL, *info = NULL; |
755 | int op, error = 0; |
756 | u32 request; |
757 | |
758 | if (!hname && !ns_name) |
759 | return -EINVAL; |
760 | |
761 | if (onexec) { |
762 | request = AA_MAY_ONEXEC; |
763 | op = OP_CHANGE_ONEXEC; |
764 | } else { |
765 | request = AA_MAY_CHANGE_PROFILE; |
766 | op = OP_CHANGE_PROFILE; |
767 | } |
768 | |
769 | cred = get_current_cred(); |
770 | profile = aa_cred_profile(cred); |
771 | |
772 | /* |
773 | * Fail explicitly requested domain transitions if no_new_privs |
774 | * and not unconfined. |
775 | * Domain transitions from unconfined are allowed even when |
776 | * no_new_privs is set because this aways results in a reduction |
777 | * of permissions. |
778 | */ |
779 | if (current->no_new_privs && !unconfined(profile)) { |
780 | put_cred(cred); |
781 | return -EPERM; |
782 | } |
783 | |
784 | if (ns_name) { |
785 | /* released below */ |
786 | ns = aa_find_namespace(profile->ns, ns_name); |
787 | if (!ns) { |
788 | /* we don't create new namespace in complain mode */ |
789 | name = ns_name; |
790 | info = "namespace not found"; |
791 | error = -ENOENT; |
792 | goto audit; |
793 | } |
794 | } else |
795 | /* released below */ |
796 | ns = aa_get_namespace(profile->ns); |
797 | |
798 | /* if the name was not specified, use the name of the current profile */ |
799 | if (!hname) { |
800 | if (unconfined(profile)) |
801 | hname = ns->unconfined->base.hname; |
802 | else |
803 | hname = profile->base.hname; |
804 | } |
805 | |
806 | perms = change_profile_perms(profile, ns, hname, request, |
807 | profile->file.start); |
808 | if (!(perms.allow & request)) { |
809 | error = -EACCES; |
810 | goto audit; |
811 | } |
812 | |
813 | /* released below */ |
814 | target = aa_lookup_profile(ns, hname); |
815 | if (!target) { |
816 | info = "profile not found"; |
817 | error = -ENOENT; |
818 | if (permtest || !COMPLAIN_MODE(profile)) |
819 | goto audit; |
820 | /* released below */ |
821 | target = aa_new_null_profile(profile, 0); |
822 | if (!target) { |
823 | info = "failed null profile create"; |
824 | error = -ENOMEM; |
825 | goto audit; |
826 | } |
827 | } |
828 | |
829 | /* check if tracing task is allowed to trace target domain */ |
830 | error = may_change_ptraced_domain(target); |
831 | if (error) { |
832 | info = "ptrace prevents transition"; |
833 | goto audit; |
834 | } |
835 | |
836 | if (permtest) |
837 | goto audit; |
838 | |
839 | if (onexec) |
840 | error = aa_set_current_onexec(target); |
841 | else |
842 | error = aa_replace_current_profile(target); |
843 | |
844 | audit: |
845 | if (!permtest) |
846 | error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request, |
847 | name, hname, GLOBAL_ROOT_UID, info, error); |
848 | |
849 | aa_put_namespace(ns); |
850 | aa_put_profile(target); |
851 | put_cred(cred); |
852 | |
853 | return error; |
854 | } |
855 |
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v2.6.34-rc5
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