diff options
Diffstat (limited to 'security/apparmor/domain.c')
-rw-r--r-- | security/apparmor/domain.c | 823 |
1 files changed, 823 insertions, 0 deletions
diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c new file mode 100644 index 00000000000..c825c6e0b63 --- /dev/null +++ b/security/apparmor/domain.c | |||
@@ -0,0 +1,823 @@ | |||
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 | * @task: task we want to change profile of (NOT NULL) | ||
54 | * @to_profile: profile to change to (NOT NULL) | ||
55 | * | ||
56 | * Check if the task is ptraced and if so if the tracing task is allowed | ||
57 | * to trace the new domain | ||
58 | * | ||
59 | * Returns: %0 or error if change not allowed | ||
60 | */ | ||
61 | static int may_change_ptraced_domain(struct task_struct *task, | ||
62 | struct aa_profile *to_profile) | ||
63 | { | ||
64 | struct task_struct *tracer; | ||
65 | const struct cred *cred = NULL; | ||
66 | struct aa_profile *tracerp = NULL; | ||
67 | int error = 0; | ||
68 | |||
69 | rcu_read_lock(); | ||
70 | tracer = tracehook_tracer_task(task); | ||
71 | if (tracer) { | ||
72 | /* released below */ | ||
73 | cred = get_task_cred(tracer); | ||
74 | tracerp = aa_cred_profile(cred); | ||
75 | } | ||
76 | rcu_read_unlock(); | ||
77 | |||
78 | /* not ptraced */ | ||
79 | if (!tracer || unconfined(tracerp)) | ||
80 | goto out; | ||
81 | |||
82 | error = aa_may_ptrace(tracer, tracerp, to_profile, PTRACE_MODE_ATTACH); | ||
83 | |||
84 | out: | ||
85 | if (cred) | ||
86 | put_cred(cred); | ||
87 | |||
88 | return error; | ||
89 | } | ||
90 | |||
91 | /** | ||
92 | * change_profile_perms - find permissions for change_profile | ||
93 | * @profile: the current profile (NOT NULL) | ||
94 | * @ns: the namespace being switched to (NOT NULL) | ||
95 | * @name: the name of the profile to change to (NOT NULL) | ||
96 | * @request: requested perms | ||
97 | * @start: state to start matching in | ||
98 | * | ||
99 | * Returns: permission set | ||
100 | */ | ||
101 | static struct file_perms change_profile_perms(struct aa_profile *profile, | ||
102 | struct aa_namespace *ns, | ||
103 | const char *name, u32 request, | ||
104 | unsigned int start) | ||
105 | { | ||
106 | struct file_perms perms; | ||
107 | struct path_cond cond = { }; | ||
108 | unsigned int state; | ||
109 | |||
110 | if (unconfined(profile)) { | ||
111 | perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC; | ||
112 | perms.audit = perms.quiet = perms.kill = 0; | ||
113 | return perms; | ||
114 | } else if (!profile->file.dfa) { | ||
115 | return nullperms; | ||
116 | } else if ((ns == profile->ns)) { | ||
117 | /* try matching against rules with out namespace prepended */ | ||
118 | aa_str_perms(profile->file.dfa, start, name, &cond, &perms); | ||
119 | if (COMBINED_PERM_MASK(perms) & request) | ||
120 | return perms; | ||
121 | } | ||
122 | |||
123 | /* try matching with namespace name and then profile */ | ||
124 | state = aa_dfa_match(profile->file.dfa, start, ns->base.name); | ||
125 | state = aa_dfa_match_len(profile->file.dfa, state, ":", 1); | ||
126 | aa_str_perms(profile->file.dfa, state, name, &cond, &perms); | ||
127 | |||
128 | return perms; | ||
129 | } | ||
130 | |||
131 | /** | ||
132 | * __attach_match_ - find an attachment match | ||
133 | * @name - to match against (NOT NULL) | ||
134 | * @head - profile list to walk (NOT NULL) | ||
135 | * | ||
136 | * Do a linear search on the profiles in the list. There is a matching | ||
137 | * preference where an exact match is preferred over a name which uses | ||
138 | * expressions to match, and matching expressions with the greatest | ||
139 | * xmatch_len are preferred. | ||
140 | * | ||
141 | * Requires: @head not be shared or have appropriate locks held | ||
142 | * | ||
143 | * Returns: profile or NULL if no match found | ||
144 | */ | ||
145 | static struct aa_profile *__attach_match(const char *name, | ||
146 | struct list_head *head) | ||
147 | { | ||
148 | int len = 0; | ||
149 | struct aa_profile *profile, *candidate = NULL; | ||
150 | |||
151 | list_for_each_entry(profile, head, base.list) { | ||
152 | if (profile->flags & PFLAG_NULL) | ||
153 | continue; | ||
154 | if (profile->xmatch && profile->xmatch_len > len) { | ||
155 | unsigned int state = aa_dfa_match(profile->xmatch, | ||
156 | DFA_START, name); | ||
157 | u32 perm = dfa_user_allow(profile->xmatch, state); | ||
158 | /* any accepting state means a valid match. */ | ||
159 | if (perm & MAY_EXEC) { | ||
160 | candidate = profile; | ||
161 | len = profile->xmatch_len; | ||
162 | } | ||
163 | } else if (!strcmp(profile->base.name, name)) | ||
164 | /* exact non-re match, no more searching required */ | ||
165 | return profile; | ||
166 | } | ||
167 | |||
168 | return candidate; | ||
169 | } | ||
170 | |||
171 | /** | ||
172 | * find_attach - do attachment search for unconfined processes | ||
173 | * @ns: the current namespace (NOT NULL) | ||
174 | * @list: list to search (NOT NULL) | ||
175 | * @name: the executable name to match against (NOT NULL) | ||
176 | * | ||
177 | * Returns: profile or NULL if no match found | ||
178 | */ | ||
179 | static struct aa_profile *find_attach(struct aa_namespace *ns, | ||
180 | struct list_head *list, const char *name) | ||
181 | { | ||
182 | struct aa_profile *profile; | ||
183 | |||
184 | read_lock(&ns->lock); | ||
185 | profile = aa_get_profile(__attach_match(name, list)); | ||
186 | read_unlock(&ns->lock); | ||
187 | |||
188 | return profile; | ||
189 | } | ||
190 | |||
191 | /** | ||
192 | * separate_fqname - separate the namespace and profile names | ||
193 | * @fqname: the fqname name to split (NOT NULL) | ||
194 | * @ns_name: the namespace name if it exists (NOT NULL) | ||
195 | * | ||
196 | * This is the xtable equivalent routine of aa_split_fqname. It finds the | ||
197 | * split in an xtable fqname which contains an embedded \0 instead of a : | ||
198 | * if a namespace is specified. This is done so the xtable is constant and | ||
199 | * isn't re-split on every lookup. | ||
200 | * | ||
201 | * Either the profile or namespace name may be optional but if the namespace | ||
202 | * is specified the profile name termination must be present. This results | ||
203 | * in the following possible encodings: | ||
204 | * profile_name\0 | ||
205 | * :ns_name\0profile_name\0 | ||
206 | * :ns_name\0\0 | ||
207 | * | ||
208 | * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table | ||
209 | * | ||
210 | * Returns: profile name if it is specified else NULL | ||
211 | */ | ||
212 | static const char *separate_fqname(const char *fqname, const char **ns_name) | ||
213 | { | ||
214 | const char *name; | ||
215 | |||
216 | if (fqname[0] == ':') { | ||
217 | /* In this case there is guaranteed to be two \0 terminators | ||
218 | * in the string. They are verified at load time by | ||
219 | * by unpack_trans_table | ||
220 | */ | ||
221 | *ns_name = fqname + 1; /* skip : */ | ||
222 | name = *ns_name + strlen(*ns_name) + 1; | ||
223 | if (!*name) | ||
224 | name = NULL; | ||
225 | } else { | ||
226 | *ns_name = NULL; | ||
227 | name = fqname; | ||
228 | } | ||
229 | |||
230 | return name; | ||
231 | } | ||
232 | |||
233 | static const char *next_name(int xtype, const char *name) | ||
234 | { | ||
235 | return NULL; | ||
236 | } | ||
237 | |||
238 | /** | ||
239 | * x_table_lookup - lookup an x transition name via transition table | ||
240 | * @profile: current profile (NOT NULL) | ||
241 | * @xindex: index into x transition table | ||
242 | * | ||
243 | * Returns: refcounted profile, or NULL on failure (MAYBE NULL) | ||
244 | */ | ||
245 | static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex) | ||
246 | { | ||
247 | struct aa_profile *new_profile = NULL; | ||
248 | struct aa_namespace *ns = profile->ns; | ||
249 | u32 xtype = xindex & AA_X_TYPE_MASK; | ||
250 | int index = xindex & AA_X_INDEX_MASK; | ||
251 | const char *name; | ||
252 | |||
253 | /* index is guaranteed to be in range, validated at load time */ | ||
254 | for (name = profile->file.trans.table[index]; !new_profile && name; | ||
255 | name = next_name(xtype, name)) { | ||
256 | struct aa_namespace *new_ns; | ||
257 | const char *xname = NULL; | ||
258 | |||
259 | new_ns = NULL; | ||
260 | if (xindex & AA_X_CHILD) { | ||
261 | /* release by caller */ | ||
262 | new_profile = aa_find_child(profile, name); | ||
263 | continue; | ||
264 | } else if (*name == ':') { | ||
265 | /* switching namespace */ | ||
266 | const char *ns_name; | ||
267 | xname = name = separate_fqname(name, &ns_name); | ||
268 | if (!xname) | ||
269 | /* no name so use profile name */ | ||
270 | xname = profile->base.hname; | ||
271 | if (*ns_name == '@') { | ||
272 | /* TODO: variable support */ | ||
273 | ; | ||
274 | } | ||
275 | /* released below */ | ||
276 | new_ns = aa_find_namespace(ns, ns_name); | ||
277 | if (!new_ns) | ||
278 | continue; | ||
279 | } else if (*name == '@') { | ||
280 | /* TODO: variable support */ | ||
281 | continue; | ||
282 | } else { | ||
283 | /* basic namespace lookup */ | ||
284 | xname = name; | ||
285 | } | ||
286 | |||
287 | /* released by caller */ | ||
288 | new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname); | ||
289 | aa_put_namespace(new_ns); | ||
290 | } | ||
291 | |||
292 | /* released by caller */ | ||
293 | return new_profile; | ||
294 | } | ||
295 | |||
296 | /** | ||
297 | * x_to_profile - get target profile for a given xindex | ||
298 | * @profile: current profile (NOT NULL) | ||
299 | * @name: name to lookup (NOT NULL) | ||
300 | * @xindex: index into x transition table | ||
301 | * | ||
302 | * find profile for a transition index | ||
303 | * | ||
304 | * Returns: refcounted profile or NULL if not found available | ||
305 | */ | ||
306 | static struct aa_profile *x_to_profile(struct aa_profile *profile, | ||
307 | const char *name, u32 xindex) | ||
308 | { | ||
309 | struct aa_profile *new_profile = NULL; | ||
310 | struct aa_namespace *ns = profile->ns; | ||
311 | u32 xtype = xindex & AA_X_TYPE_MASK; | ||
312 | |||
313 | switch (xtype) { | ||
314 | case AA_X_NONE: | ||
315 | /* fail exec unless ix || ux fallback - handled by caller */ | ||
316 | return NULL; | ||
317 | case AA_X_NAME: | ||
318 | if (xindex & AA_X_CHILD) | ||
319 | /* released by caller */ | ||
320 | new_profile = find_attach(ns, &profile->base.profiles, | ||
321 | name); | ||
322 | else | ||
323 | /* released by caller */ | ||
324 | new_profile = find_attach(ns, &ns->base.profiles, | ||
325 | name); | ||
326 | break; | ||
327 | case AA_X_TABLE: | ||
328 | /* released by caller */ | ||
329 | new_profile = x_table_lookup(profile, xindex); | ||
330 | break; | ||
331 | } | ||
332 | |||
333 | /* released by caller */ | ||
334 | return new_profile; | ||
335 | } | ||
336 | |||
337 | /** | ||
338 | * apparmor_bprm_set_creds - set the new creds on the bprm struct | ||
339 | * @bprm: binprm for the exec (NOT NULL) | ||
340 | * | ||
341 | * Returns: %0 or error on failure | ||
342 | */ | ||
343 | int apparmor_bprm_set_creds(struct linux_binprm *bprm) | ||
344 | { | ||
345 | struct aa_task_cxt *cxt; | ||
346 | struct aa_profile *profile, *new_profile = NULL; | ||
347 | struct aa_namespace *ns; | ||
348 | char *buffer = NULL; | ||
349 | unsigned int state; | ||
350 | struct file_perms perms = {}; | ||
351 | struct path_cond cond = { | ||
352 | bprm->file->f_path.dentry->d_inode->i_uid, | ||
353 | bprm->file->f_path.dentry->d_inode->i_mode | ||
354 | }; | ||
355 | const char *name = NULL, *target = NULL, *info = NULL; | ||
356 | int error = cap_bprm_set_creds(bprm); | ||
357 | if (error) | ||
358 | return error; | ||
359 | |||
360 | if (bprm->cred_prepared) | ||
361 | return 0; | ||
362 | |||
363 | cxt = bprm->cred->security; | ||
364 | BUG_ON(!cxt); | ||
365 | |||
366 | profile = aa_get_profile(aa_newest_version(cxt->profile)); | ||
367 | /* | ||
368 | * get the namespace from the replacement profile as replacement | ||
369 | * can change the namespace | ||
370 | */ | ||
371 | ns = profile->ns; | ||
372 | state = profile->file.start; | ||
373 | |||
374 | /* buffer freed below, name is pointer into buffer */ | ||
375 | error = aa_get_name(&bprm->file->f_path, profile->path_flags, &buffer, | ||
376 | &name); | ||
377 | if (error) { | ||
378 | if (profile->flags & | ||
379 | (PFLAG_IX_ON_NAME_ERROR | PFLAG_UNCONFINED)) | ||
380 | error = 0; | ||
381 | info = "Exec failed name resolution"; | ||
382 | name = bprm->filename; | ||
383 | goto audit; | ||
384 | } | ||
385 | |||
386 | /* Test for onexec first as onexec directives override other | ||
387 | * x transitions. | ||
388 | */ | ||
389 | if (unconfined(profile)) { | ||
390 | /* unconfined task */ | ||
391 | if (cxt->onexec) | ||
392 | /* change_profile on exec already been granted */ | ||
393 | new_profile = aa_get_profile(cxt->onexec); | ||
394 | else | ||
395 | new_profile = find_attach(ns, &ns->base.profiles, name); | ||
396 | if (!new_profile) | ||
397 | goto cleanup; | ||
398 | goto apply; | ||
399 | } | ||
400 | |||
401 | /* find exec permissions for name */ | ||
402 | state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms); | ||
403 | if (cxt->onexec) { | ||
404 | struct file_perms cp; | ||
405 | info = "change_profile onexec"; | ||
406 | if (!(perms.allow & AA_MAY_ONEXEC)) | ||
407 | goto audit; | ||
408 | |||
409 | /* test if this exec can be paired with change_profile onexec. | ||
410 | * onexec permission is linked to exec with a standard pairing | ||
411 | * exec\0change_profile | ||
412 | */ | ||
413 | state = aa_dfa_null_transition(profile->file.dfa, state); | ||
414 | cp = change_profile_perms(profile, cxt->onexec->ns, name, | ||
415 | AA_MAY_ONEXEC, state); | ||
416 | |||
417 | if (!(cp.allow & AA_MAY_ONEXEC)) | ||
418 | goto audit; | ||
419 | new_profile = aa_get_profile(aa_newest_version(cxt->onexec)); | ||
420 | goto apply; | ||
421 | } | ||
422 | |||
423 | if (perms.allow & MAY_EXEC) { | ||
424 | /* exec permission determine how to transition */ | ||
425 | new_profile = x_to_profile(profile, name, perms.xindex); | ||
426 | if (!new_profile) { | ||
427 | if (perms.xindex & AA_X_INHERIT) { | ||
428 | /* (p|c|n)ix - don't change profile but do | ||
429 | * use the newest version, which was picked | ||
430 | * up above when getting profile | ||
431 | */ | ||
432 | info = "ix fallback"; | ||
433 | new_profile = aa_get_profile(profile); | ||
434 | goto x_clear; | ||
435 | } else if (perms.xindex & AA_X_UNCONFINED) { | ||
436 | new_profile = aa_get_profile(ns->unconfined); | ||
437 | info = "ux fallback"; | ||
438 | } else { | ||
439 | error = -ENOENT; | ||
440 | info = "profile not found"; | ||
441 | } | ||
442 | } | ||
443 | } else if (COMPLAIN_MODE(profile)) { | ||
444 | /* no exec permission - are we in learning mode */ | ||
445 | new_profile = aa_new_null_profile(profile, 0); | ||
446 | if (!new_profile) { | ||
447 | error = -ENOMEM; | ||
448 | info = "could not create null profile"; | ||
449 | } else { | ||
450 | error = -EACCES; | ||
451 | target = new_profile->base.hname; | ||
452 | } | ||
453 | perms.xindex |= AA_X_UNSAFE; | ||
454 | } else | ||
455 | /* fail exec */ | ||
456 | error = -EACCES; | ||
457 | |||
458 | if (!new_profile) | ||
459 | goto audit; | ||
460 | |||
461 | if (bprm->unsafe & LSM_UNSAFE_SHARE) { | ||
462 | /* FIXME: currently don't mediate shared state */ | ||
463 | ; | ||
464 | } | ||
465 | |||
466 | if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { | ||
467 | error = may_change_ptraced_domain(current, new_profile); | ||
468 | if (error) { | ||
469 | aa_put_profile(new_profile); | ||
470 | goto audit; | ||
471 | } | ||
472 | } | ||
473 | |||
474 | /* Determine if secure exec is needed. | ||
475 | * Can be at this point for the following reasons: | ||
476 | * 1. unconfined switching to confined | ||
477 | * 2. confined switching to different confinement | ||
478 | * 3. confined switching to unconfined | ||
479 | * | ||
480 | * Cases 2 and 3 are marked as requiring secure exec | ||
481 | * (unless policy specified "unsafe exec") | ||
482 | * | ||
483 | * bprm->unsafe is used to cache the AA_X_UNSAFE permission | ||
484 | * to avoid having to recompute in secureexec | ||
485 | */ | ||
486 | if (!(perms.xindex & AA_X_UNSAFE)) { | ||
487 | AA_DEBUG("scrubbing environment variables for %s profile=%s\n", | ||
488 | name, new_profile->base.hname); | ||
489 | bprm->unsafe |= AA_SECURE_X_NEEDED; | ||
490 | } | ||
491 | apply: | ||
492 | target = new_profile->base.hname; | ||
493 | /* when transitioning profiles clear unsafe personality bits */ | ||
494 | bprm->per_clear |= PER_CLEAR_ON_SETID; | ||
495 | |||
496 | x_clear: | ||
497 | aa_put_profile(cxt->profile); | ||
498 | /* transfer new profile reference will be released when cxt is freed */ | ||
499 | cxt->profile = new_profile; | ||
500 | |||
501 | /* clear out all temporary/transitional state from the context */ | ||
502 | aa_put_profile(cxt->previous); | ||
503 | aa_put_profile(cxt->onexec); | ||
504 | cxt->previous = NULL; | ||
505 | cxt->onexec = NULL; | ||
506 | cxt->token = 0; | ||
507 | |||
508 | audit: | ||
509 | error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC, | ||
510 | name, target, cond.uid, info, error); | ||
511 | |||
512 | cleanup: | ||
513 | aa_put_profile(profile); | ||
514 | kfree(buffer); | ||
515 | |||
516 | return error; | ||
517 | } | ||
518 | |||
519 | /** | ||
520 | * apparmor_bprm_secureexec - determine if secureexec is needed | ||
521 | * @bprm: binprm for exec (NOT NULL) | ||
522 | * | ||
523 | * Returns: %1 if secureexec is needed else %0 | ||
524 | */ | ||
525 | int apparmor_bprm_secureexec(struct linux_binprm *bprm) | ||
526 | { | ||
527 | int ret = cap_bprm_secureexec(bprm); | ||
528 | |||
529 | /* the decision to use secure exec is computed in set_creds | ||
530 | * and stored in bprm->unsafe. | ||
531 | */ | ||
532 | if (!ret && (bprm->unsafe & AA_SECURE_X_NEEDED)) | ||
533 | ret = 1; | ||
534 | |||
535 | return ret; | ||
536 | } | ||
537 | |||
538 | /** | ||
539 | * apparmor_bprm_committing_creds - do task cleanup on committing new creds | ||
540 | * @bprm: binprm for the exec (NOT NULL) | ||
541 | */ | ||
542 | void apparmor_bprm_committing_creds(struct linux_binprm *bprm) | ||
543 | { | ||
544 | struct aa_profile *profile = __aa_current_profile(); | ||
545 | struct aa_task_cxt *new_cxt = bprm->cred->security; | ||
546 | |||
547 | /* bail out if unconfined or not changing profile */ | ||
548 | if ((new_cxt->profile == profile) || | ||
549 | (unconfined(new_cxt->profile))) | ||
550 | return; | ||
551 | |||
552 | current->pdeath_signal = 0; | ||
553 | |||
554 | /* reset soft limits and set hard limits for the new profile */ | ||
555 | __aa_transition_rlimits(profile, new_cxt->profile); | ||
556 | } | ||
557 | |||
558 | /** | ||
559 | * apparmor_bprm_commited_cred - do cleanup after new creds committed | ||
560 | * @bprm: binprm for the exec (NOT NULL) | ||
561 | */ | ||
562 | void apparmor_bprm_committed_creds(struct linux_binprm *bprm) | ||
563 | { | ||
564 | /* TODO: cleanup signals - ipc mediation */ | ||
565 | return; | ||
566 | } | ||
567 | |||
568 | /* | ||
569 | * Functions for self directed profile change | ||
570 | */ | ||
571 | |||
572 | /** | ||
573 | * new_compound_name - create an hname with @n2 appended to @n1 | ||
574 | * @n1: base of hname (NOT NULL) | ||
575 | * @n2: name to append (NOT NULL) | ||
576 | * | ||
577 | * Returns: new name or NULL on error | ||
578 | */ | ||
579 | static char *new_compound_name(const char *n1, const char *n2) | ||
580 | { | ||
581 | char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL); | ||
582 | if (name) | ||
583 | sprintf(name, "%s//%s", n1, n2); | ||
584 | return name; | ||
585 | } | ||
586 | |||
587 | /** | ||
588 | * aa_change_hat - change hat to/from subprofile | ||
589 | * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0) | ||
590 | * @count: number of hat names in @hats | ||
591 | * @token: magic value to validate the hat change | ||
592 | * @permtest: true if this is just a permission test | ||
593 | * | ||
594 | * Change to the first profile specified in @hats that exists, and store | ||
595 | * the @hat_magic in the current task context. If the count == 0 and the | ||
596 | * @token matches that stored in the current task context, return to the | ||
597 | * top level profile. | ||
598 | * | ||
599 | * Returns %0 on success, error otherwise. | ||
600 | */ | ||
601 | int aa_change_hat(const char *hats[], int count, u64 token, bool permtest) | ||
602 | { | ||
603 | const struct cred *cred; | ||
604 | struct aa_task_cxt *cxt; | ||
605 | struct aa_profile *profile, *previous_profile, *hat = NULL; | ||
606 | char *name = NULL; | ||
607 | int i; | ||
608 | struct file_perms perms = {}; | ||
609 | const char *target = NULL, *info = NULL; | ||
610 | int error = 0; | ||
611 | |||
612 | /* released below */ | ||
613 | cred = get_current_cred(); | ||
614 | cxt = cred->security; | ||
615 | profile = aa_cred_profile(cred); | ||
616 | previous_profile = cxt->previous; | ||
617 | |||
618 | if (unconfined(profile)) { | ||
619 | info = "unconfined"; | ||
620 | error = -EPERM; | ||
621 | goto audit; | ||
622 | } | ||
623 | |||
624 | if (count) { | ||
625 | /* attempting to change into a new hat or switch to a sibling */ | ||
626 | struct aa_profile *root; | ||
627 | root = PROFILE_IS_HAT(profile) ? profile->parent : profile; | ||
628 | |||
629 | /* find first matching hat */ | ||
630 | for (i = 0; i < count && !hat; i++) | ||
631 | /* released below */ | ||
632 | hat = aa_find_child(root, hats[i]); | ||
633 | if (!hat) { | ||
634 | if (!COMPLAIN_MODE(root) || permtest) { | ||
635 | if (list_empty(&root->base.profiles)) | ||
636 | error = -ECHILD; | ||
637 | else | ||
638 | error = -ENOENT; | ||
639 | goto out; | ||
640 | } | ||
641 | |||
642 | /* | ||
643 | * In complain mode and failed to match any hats. | ||
644 | * Audit the failure is based off of the first hat | ||
645 | * supplied. This is done due how userspace | ||
646 | * interacts with change_hat. | ||
647 | * | ||
648 | * TODO: Add logging of all failed hats | ||
649 | */ | ||
650 | |||
651 | /* freed below */ | ||
652 | name = new_compound_name(root->base.hname, hats[0]); | ||
653 | target = name; | ||
654 | /* released below */ | ||
655 | hat = aa_new_null_profile(profile, 1); | ||
656 | if (!hat) { | ||
657 | info = "failed null profile create"; | ||
658 | error = -ENOMEM; | ||
659 | goto audit; | ||
660 | } | ||
661 | } else { | ||
662 | target = hat->base.hname; | ||
663 | if (!PROFILE_IS_HAT(hat)) { | ||
664 | info = "target not hat"; | ||
665 | error = -EPERM; | ||
666 | goto audit; | ||
667 | } | ||
668 | } | ||
669 | |||
670 | error = may_change_ptraced_domain(current, hat); | ||
671 | if (error) { | ||
672 | info = "ptraced"; | ||
673 | error = -EPERM; | ||
674 | goto audit; | ||
675 | } | ||
676 | |||
677 | if (!permtest) { | ||
678 | error = aa_set_current_hat(hat, token); | ||
679 | if (error == -EACCES) | ||
680 | /* kill task in case of brute force attacks */ | ||
681 | perms.kill = AA_MAY_CHANGEHAT; | ||
682 | else if (name && !error) | ||
683 | /* reset error for learning of new hats */ | ||
684 | error = -ENOENT; | ||
685 | } | ||
686 | } else if (previous_profile) { | ||
687 | /* Return to saved profile. Kill task if restore fails | ||
688 | * to avoid brute force attacks | ||
689 | */ | ||
690 | target = previous_profile->base.hname; | ||
691 | error = aa_restore_previous_profile(token); | ||
692 | perms.kill = AA_MAY_CHANGEHAT; | ||
693 | } else | ||
694 | /* ignore restores when there is no saved profile */ | ||
695 | goto out; | ||
696 | |||
697 | audit: | ||
698 | if (!permtest) | ||
699 | error = aa_audit_file(profile, &perms, GFP_KERNEL, | ||
700 | OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL, | ||
701 | target, 0, info, error); | ||
702 | |||
703 | out: | ||
704 | aa_put_profile(hat); | ||
705 | kfree(name); | ||
706 | put_cred(cred); | ||
707 | |||
708 | return error; | ||
709 | } | ||
710 | |||
711 | /** | ||
712 | * aa_change_profile - perform a one-way profile transition | ||
713 | * @ns_name: name of the profile namespace to change to (MAYBE NULL) | ||
714 | * @hname: name of profile to change to (MAYBE NULL) | ||
715 | * @onexec: whether this transition is to take place immediately or at exec | ||
716 | * @permtest: true if this is just a permission test | ||
717 | * | ||
718 | * Change to new profile @name. Unlike with hats, there is no way | ||
719 | * to change back. If @name isn't specified the current profile name is | ||
720 | * used. | ||
721 | * If @onexec then the transition is delayed until | ||
722 | * the next exec. | ||
723 | * | ||
724 | * Returns %0 on success, error otherwise. | ||
725 | */ | ||
726 | int aa_change_profile(const char *ns_name, const char *hname, bool onexec, | ||
727 | bool permtest) | ||
728 | { | ||
729 | const struct cred *cred; | ||
730 | struct aa_task_cxt *cxt; | ||
731 | struct aa_profile *profile, *target = NULL; | ||
732 | struct aa_namespace *ns = NULL; | ||
733 | struct file_perms perms = {}; | ||
734 | const char *name = NULL, *info = NULL; | ||
735 | int op, error = 0; | ||
736 | u32 request; | ||
737 | |||
738 | if (!hname && !ns_name) | ||
739 | return -EINVAL; | ||
740 | |||
741 | if (onexec) { | ||
742 | request = AA_MAY_ONEXEC; | ||
743 | op = OP_CHANGE_ONEXEC; | ||
744 | } else { | ||
745 | request = AA_MAY_CHANGE_PROFILE; | ||
746 | op = OP_CHANGE_PROFILE; | ||
747 | } | ||
748 | |||
749 | cred = get_current_cred(); | ||
750 | cxt = cred->security; | ||
751 | profile = aa_cred_profile(cred); | ||
752 | |||
753 | if (ns_name) { | ||
754 | /* released below */ | ||
755 | ns = aa_find_namespace(profile->ns, ns_name); | ||
756 | if (!ns) { | ||
757 | /* we don't create new namespace in complain mode */ | ||
758 | name = ns_name; | ||
759 | info = "namespace not found"; | ||
760 | error = -ENOENT; | ||
761 | goto audit; | ||
762 | } | ||
763 | } else | ||
764 | /* released below */ | ||
765 | ns = aa_get_namespace(profile->ns); | ||
766 | |||
767 | /* if the name was not specified, use the name of the current profile */ | ||
768 | if (!hname) { | ||
769 | if (unconfined(profile)) | ||
770 | hname = ns->unconfined->base.hname; | ||
771 | else | ||
772 | hname = profile->base.hname; | ||
773 | } | ||
774 | |||
775 | perms = change_profile_perms(profile, ns, hname, request, | ||
776 | profile->file.start); | ||
777 | if (!(perms.allow & request)) { | ||
778 | error = -EACCES; | ||
779 | goto audit; | ||
780 | } | ||
781 | |||
782 | /* released below */ | ||
783 | target = aa_lookup_profile(ns, hname); | ||
784 | if (!target) { | ||
785 | info = "profile not found"; | ||
786 | error = -ENOENT; | ||
787 | if (permtest || !COMPLAIN_MODE(profile)) | ||
788 | goto audit; | ||
789 | /* released below */ | ||
790 | target = aa_new_null_profile(profile, 0); | ||
791 | if (!target) { | ||
792 | info = "failed null profile create"; | ||
793 | error = -ENOMEM; | ||
794 | goto audit; | ||
795 | } | ||
796 | } | ||
797 | |||
798 | /* check if tracing task is allowed to trace target domain */ | ||
799 | error = may_change_ptraced_domain(current, target); | ||
800 | if (error) { | ||
801 | info = "ptrace prevents transition"; | ||
802 | goto audit; | ||
803 | } | ||
804 | |||
805 | if (permtest) | ||
806 | goto audit; | ||
807 | |||
808 | if (onexec) | ||
809 | error = aa_set_current_onexec(target); | ||
810 | else | ||
811 | error = aa_replace_current_profile(target); | ||
812 | |||
813 | audit: | ||
814 | if (!permtest) | ||
815 | error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request, | ||
816 | name, hname, 0, info, error); | ||
817 | |||
818 | aa_put_namespace(ns); | ||
819 | aa_put_profile(target); | ||
820 | put_cred(cred); | ||
821 | |||
822 | return error; | ||
823 | } | ||