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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" | |
cff281f6 | 32 | #include "include/policy_ns.h" |
898127c3 JJ |
33 | |
34 | /** | |
35 | * aa_free_domain_entries - free entries in a domain table | |
36 | * @domain: the domain table to free (MAYBE NULL) | |
37 | */ | |
38 | void aa_free_domain_entries(struct aa_domain *domain) | |
39 | { | |
40 | int i; | |
41 | if (domain) { | |
42 | if (!domain->table) | |
43 | return; | |
44 | ||
45 | for (i = 0; i < domain->size; i++) | |
46 | kzfree(domain->table[i]); | |
47 | kzfree(domain->table); | |
48 | domain->table = NULL; | |
49 | } | |
50 | } | |
51 | ||
52 | /** | |
53 | * may_change_ptraced_domain - check if can change profile on ptraced task | |
898127c3 JJ |
54 | * @to_profile: profile to change to (NOT NULL) |
55 | * | |
51775fe7 | 56 | * Check if current is ptraced and if so if the tracing task is allowed |
898127c3 JJ |
57 | * to trace the new domain |
58 | * | |
59 | * Returns: %0 or error if change not allowed | |
60 | */ | |
51775fe7 | 61 | static int may_change_ptraced_domain(struct aa_profile *to_profile) |
898127c3 JJ |
62 | { |
63 | struct task_struct *tracer; | |
898127c3 JJ |
64 | struct aa_profile *tracerp = NULL; |
65 | int error = 0; | |
66 | ||
67 | rcu_read_lock(); | |
51775fe7 | 68 | tracer = ptrace_parent(current); |
3cfcc19e | 69 | if (tracer) |
898127c3 | 70 | /* released below */ |
3cfcc19e | 71 | tracerp = aa_get_task_profile(tracer); |
898127c3 JJ |
72 | |
73 | /* not ptraced */ | |
74 | if (!tracer || unconfined(tracerp)) | |
75 | goto out; | |
76 | ||
dd0c6e86 | 77 | error = aa_may_ptrace(tracerp, to_profile, PTRACE_MODE_ATTACH); |
898127c3 JJ |
78 | |
79 | out: | |
04fdc099 | 80 | rcu_read_unlock(); |
3cfcc19e | 81 | aa_put_profile(tracerp); |
898127c3 JJ |
82 | |
83 | return error; | |
84 | } | |
85 | ||
86 | /** | |
87 | * change_profile_perms - find permissions for change_profile | |
88 | * @profile: the current profile (NOT NULL) | |
89 | * @ns: the namespace being switched to (NOT NULL) | |
90 | * @name: the name of the profile to change to (NOT NULL) | |
91 | * @request: requested perms | |
92 | * @start: state to start matching in | |
93 | * | |
94 | * Returns: permission set | |
95 | */ | |
96 | static struct file_perms change_profile_perms(struct aa_profile *profile, | |
98849dff | 97 | struct aa_ns *ns, |
898127c3 JJ |
98 | const char *name, u32 request, |
99 | unsigned int start) | |
100 | { | |
101 | struct file_perms perms; | |
102 | struct path_cond cond = { }; | |
103 | unsigned int state; | |
104 | ||
105 | if (unconfined(profile)) { | |
106 | perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC; | |
107 | perms.audit = perms.quiet = perms.kill = 0; | |
108 | return perms; | |
109 | } else if (!profile->file.dfa) { | |
110 | return nullperms; | |
111 | } else if ((ns == profile->ns)) { | |
112 | /* try matching against rules with out namespace prepended */ | |
113 | aa_str_perms(profile->file.dfa, start, name, &cond, &perms); | |
114 | if (COMBINED_PERM_MASK(perms) & request) | |
115 | return perms; | |
116 | } | |
117 | ||
118 | /* try matching with namespace name and then profile */ | |
119 | state = aa_dfa_match(profile->file.dfa, start, ns->base.name); | |
120 | state = aa_dfa_match_len(profile->file.dfa, state, ":", 1); | |
121 | aa_str_perms(profile->file.dfa, state, name, &cond, &perms); | |
122 | ||
123 | return perms; | |
124 | } | |
125 | ||
126 | /** | |
127 | * __attach_match_ - find an attachment match | |
128 | * @name - to match against (NOT NULL) | |
129 | * @head - profile list to walk (NOT NULL) | |
130 | * | |
131 | * Do a linear search on the profiles in the list. There is a matching | |
132 | * preference where an exact match is preferred over a name which uses | |
133 | * expressions to match, and matching expressions with the greatest | |
134 | * xmatch_len are preferred. | |
135 | * | |
136 | * Requires: @head not be shared or have appropriate locks held | |
137 | * | |
138 | * Returns: profile or NULL if no match found | |
139 | */ | |
140 | static struct aa_profile *__attach_match(const char *name, | |
141 | struct list_head *head) | |
142 | { | |
143 | int len = 0; | |
144 | struct aa_profile *profile, *candidate = NULL; | |
145 | ||
01e2b670 | 146 | list_for_each_entry_rcu(profile, head, base.list) { |
898127c3 JJ |
147 | if (profile->flags & PFLAG_NULL) |
148 | continue; | |
149 | if (profile->xmatch && profile->xmatch_len > len) { | |
150 | unsigned int state = aa_dfa_match(profile->xmatch, | |
151 | DFA_START, name); | |
152 | u32 perm = dfa_user_allow(profile->xmatch, state); | |
153 | /* any accepting state means a valid match. */ | |
154 | if (perm & MAY_EXEC) { | |
155 | candidate = profile; | |
156 | len = profile->xmatch_len; | |
157 | } | |
158 | } else if (!strcmp(profile->base.name, name)) | |
159 | /* exact non-re match, no more searching required */ | |
160 | return profile; | |
161 | } | |
162 | ||
163 | return candidate; | |
164 | } | |
165 | ||
166 | /** | |
167 | * find_attach - do attachment search for unconfined processes | |
168 | * @ns: the current namespace (NOT NULL) | |
169 | * @list: list to search (NOT NULL) | |
170 | * @name: the executable name to match against (NOT NULL) | |
171 | * | |
172 | * Returns: profile or NULL if no match found | |
173 | */ | |
98849dff | 174 | static struct aa_profile *find_attach(struct aa_ns *ns, |
898127c3 JJ |
175 | struct list_head *list, const char *name) |
176 | { | |
177 | struct aa_profile *profile; | |
178 | ||
01e2b670 | 179 | rcu_read_lock(); |
898127c3 | 180 | profile = aa_get_profile(__attach_match(name, list)); |
01e2b670 | 181 | rcu_read_unlock(); |
898127c3 JJ |
182 | |
183 | return profile; | |
184 | } | |
185 | ||
186 | /** | |
187 | * separate_fqname - separate the namespace and profile names | |
188 | * @fqname: the fqname name to split (NOT NULL) | |
189 | * @ns_name: the namespace name if it exists (NOT NULL) | |
190 | * | |
191 | * This is the xtable equivalent routine of aa_split_fqname. It finds the | |
192 | * split in an xtable fqname which contains an embedded \0 instead of a : | |
193 | * if a namespace is specified. This is done so the xtable is constant and | |
194 | * isn't re-split on every lookup. | |
195 | * | |
196 | * Either the profile or namespace name may be optional but if the namespace | |
197 | * is specified the profile name termination must be present. This results | |
198 | * in the following possible encodings: | |
199 | * profile_name\0 | |
200 | * :ns_name\0profile_name\0 | |
201 | * :ns_name\0\0 | |
202 | * | |
203 | * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table | |
204 | * | |
205 | * Returns: profile name if it is specified else NULL | |
206 | */ | |
207 | static const char *separate_fqname(const char *fqname, const char **ns_name) | |
208 | { | |
209 | const char *name; | |
210 | ||
211 | if (fqname[0] == ':') { | |
212 | /* In this case there is guaranteed to be two \0 terminators | |
213 | * in the string. They are verified at load time by | |
214 | * by unpack_trans_table | |
215 | */ | |
216 | *ns_name = fqname + 1; /* skip : */ | |
217 | name = *ns_name + strlen(*ns_name) + 1; | |
218 | if (!*name) | |
219 | name = NULL; | |
220 | } else { | |
221 | *ns_name = NULL; | |
222 | name = fqname; | |
223 | } | |
224 | ||
225 | return name; | |
226 | } | |
227 | ||
228 | static const char *next_name(int xtype, const char *name) | |
229 | { | |
230 | return NULL; | |
231 | } | |
232 | ||
233 | /** | |
234 | * x_table_lookup - lookup an x transition name via transition table | |
235 | * @profile: current profile (NOT NULL) | |
236 | * @xindex: index into x transition table | |
237 | * | |
238 | * Returns: refcounted profile, or NULL on failure (MAYBE NULL) | |
239 | */ | |
240 | static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex) | |
241 | { | |
242 | struct aa_profile *new_profile = NULL; | |
98849dff | 243 | struct aa_ns *ns = profile->ns; |
898127c3 JJ |
244 | u32 xtype = xindex & AA_X_TYPE_MASK; |
245 | int index = xindex & AA_X_INDEX_MASK; | |
246 | const char *name; | |
247 | ||
248 | /* index is guaranteed to be in range, validated at load time */ | |
249 | for (name = profile->file.trans.table[index]; !new_profile && name; | |
250 | name = next_name(xtype, name)) { | |
98849dff | 251 | struct aa_ns *new_ns; |
898127c3 JJ |
252 | const char *xname = NULL; |
253 | ||
254 | new_ns = NULL; | |
255 | if (xindex & AA_X_CHILD) { | |
256 | /* release by caller */ | |
257 | new_profile = aa_find_child(profile, name); | |
258 | continue; | |
259 | } else if (*name == ':') { | |
260 | /* switching namespace */ | |
261 | const char *ns_name; | |
262 | xname = name = separate_fqname(name, &ns_name); | |
263 | if (!xname) | |
264 | /* no name so use profile name */ | |
265 | xname = profile->base.hname; | |
266 | if (*ns_name == '@') { | |
267 | /* TODO: variable support */ | |
268 | ; | |
269 | } | |
270 | /* released below */ | |
98849dff | 271 | new_ns = aa_find_ns(ns, ns_name); |
898127c3 JJ |
272 | if (!new_ns) |
273 | continue; | |
274 | } else if (*name == '@') { | |
275 | /* TODO: variable support */ | |
276 | continue; | |
277 | } else { | |
278 | /* basic namespace lookup */ | |
279 | xname = name; | |
280 | } | |
281 | ||
282 | /* released by caller */ | |
283 | new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname); | |
98849dff | 284 | aa_put_ns(new_ns); |
898127c3 JJ |
285 | } |
286 | ||
287 | /* released by caller */ | |
288 | return new_profile; | |
289 | } | |
290 | ||
291 | /** | |
292 | * x_to_profile - get target profile for a given xindex | |
293 | * @profile: current profile (NOT NULL) | |
294 | * @name: name to lookup (NOT NULL) | |
295 | * @xindex: index into x transition table | |
296 | * | |
297 | * find profile for a transition index | |
298 | * | |
299 | * Returns: refcounted profile or NULL if not found available | |
300 | */ | |
301 | static struct aa_profile *x_to_profile(struct aa_profile *profile, | |
302 | const char *name, u32 xindex) | |
303 | { | |
304 | struct aa_profile *new_profile = NULL; | |
98849dff | 305 | struct aa_ns *ns = profile->ns; |
898127c3 JJ |
306 | u32 xtype = xindex & AA_X_TYPE_MASK; |
307 | ||
308 | switch (xtype) { | |
309 | case AA_X_NONE: | |
310 | /* fail exec unless ix || ux fallback - handled by caller */ | |
311 | return NULL; | |
312 | case AA_X_NAME: | |
313 | if (xindex & AA_X_CHILD) | |
314 | /* released by caller */ | |
315 | new_profile = find_attach(ns, &profile->base.profiles, | |
316 | name); | |
317 | else | |
318 | /* released by caller */ | |
319 | new_profile = find_attach(ns, &ns->base.profiles, | |
320 | name); | |
321 | break; | |
322 | case AA_X_TABLE: | |
323 | /* released by caller */ | |
324 | new_profile = x_table_lookup(profile, xindex); | |
325 | break; | |
326 | } | |
327 | ||
328 | /* released by caller */ | |
329 | return new_profile; | |
330 | } | |
331 | ||
332 | /** | |
333 | * apparmor_bprm_set_creds - set the new creds on the bprm struct | |
334 | * @bprm: binprm for the exec (NOT NULL) | |
335 | * | |
336 | * Returns: %0 or error on failure | |
337 | */ | |
338 | int apparmor_bprm_set_creds(struct linux_binprm *bprm) | |
339 | { | |
340 | struct aa_task_cxt *cxt; | |
341 | struct aa_profile *profile, *new_profile = NULL; | |
98849dff | 342 | struct aa_ns *ns; |
898127c3 JJ |
343 | char *buffer = NULL; |
344 | unsigned int state; | |
345 | struct file_perms perms = {}; | |
346 | struct path_cond cond = { | |
496ad9aa AV |
347 | file_inode(bprm->file)->i_uid, |
348 | file_inode(bprm->file)->i_mode | |
898127c3 | 349 | }; |
f7da2de0 | 350 | const char *name = NULL, *info = NULL; |
b1d9e6b0 | 351 | int error = 0; |
898127c3 JJ |
352 | |
353 | if (bprm->cred_prepared) | |
354 | return 0; | |
355 | ||
214beaca | 356 | cxt = cred_cxt(bprm->cred); |
898127c3 JJ |
357 | BUG_ON(!cxt); |
358 | ||
77b071b3 | 359 | profile = aa_get_newest_profile(cxt->profile); |
898127c3 JJ |
360 | /* |
361 | * get the namespace from the replacement profile as replacement | |
362 | * can change the namespace | |
363 | */ | |
364 | ns = profile->ns; | |
365 | state = profile->file.start; | |
366 | ||
367 | /* buffer freed below, name is pointer into buffer */ | |
57fa1e18 JJ |
368 | error = aa_path_name(&bprm->file->f_path, profile->path_flags, &buffer, |
369 | &name, &info); | |
898127c3 | 370 | if (error) { |
03816507 JJ |
371 | if (unconfined(profile) || |
372 | (profile->flags & PFLAG_IX_ON_NAME_ERROR)) | |
898127c3 | 373 | error = 0; |
898127c3 JJ |
374 | name = bprm->filename; |
375 | goto audit; | |
376 | } | |
377 | ||
378 | /* Test for onexec first as onexec directives override other | |
379 | * x transitions. | |
380 | */ | |
381 | if (unconfined(profile)) { | |
382 | /* unconfined task */ | |
383 | if (cxt->onexec) | |
384 | /* change_profile on exec already been granted */ | |
385 | new_profile = aa_get_profile(cxt->onexec); | |
386 | else | |
387 | new_profile = find_attach(ns, &ns->base.profiles, name); | |
388 | if (!new_profile) | |
389 | goto cleanup; | |
c29bceb3 JJ |
390 | /* |
391 | * NOTE: Domain transitions from unconfined are allowed | |
392 | * even when no_new_privs is set because this aways results | |
393 | * in a further reduction of permissions. | |
394 | */ | |
898127c3 JJ |
395 | goto apply; |
396 | } | |
397 | ||
398 | /* find exec permissions for name */ | |
399 | state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms); | |
400 | if (cxt->onexec) { | |
401 | struct file_perms cp; | |
402 | info = "change_profile onexec"; | |
f7da2de0 | 403 | new_profile = aa_get_newest_profile(cxt->onexec); |
898127c3 JJ |
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); | |
0421ea91 JJ |
412 | cp = change_profile_perms(profile, cxt->onexec->ns, |
413 | cxt->onexec->base.name, | |
898127c3 JJ |
414 | AA_MAY_ONEXEC, state); |
415 | ||
416 | if (!(cp.allow & AA_MAY_ONEXEC)) | |
417 | goto audit; | |
898127c3 JJ |
418 | goto apply; |
419 | } | |
420 | ||
421 | if (perms.allow & MAY_EXEC) { | |
422 | /* exec permission determine how to transition */ | |
423 | new_profile = x_to_profile(profile, name, perms.xindex); | |
424 | if (!new_profile) { | |
425 | if (perms.xindex & AA_X_INHERIT) { | |
426 | /* (p|c|n)ix - don't change profile but do | |
427 | * use the newest version, which was picked | |
428 | * up above when getting profile | |
429 | */ | |
430 | info = "ix fallback"; | |
431 | new_profile = aa_get_profile(profile); | |
432 | goto x_clear; | |
433 | } else if (perms.xindex & AA_X_UNCONFINED) { | |
fa2ac468 | 434 | new_profile = aa_get_newest_profile(ns->unconfined); |
898127c3 JJ |
435 | info = "ux fallback"; |
436 | } else { | |
9049a792 | 437 | error = -EACCES; |
898127c3 | 438 | info = "profile not found"; |
17322cc3 JJ |
439 | /* remove MAY_EXEC to audit as failure */ |
440 | perms.allow &= ~MAY_EXEC; | |
898127c3 JJ |
441 | } |
442 | } | |
443 | } else if (COMPLAIN_MODE(profile)) { | |
444 | /* no exec permission - are we in learning mode */ | |
181f7c97 JJ |
445 | new_profile = aa_new_null_profile(profile, false, name, |
446 | GFP_ATOMIC); | |
898127c3 JJ |
447 | if (!new_profile) { |
448 | error = -ENOMEM; | |
449 | info = "could not create null profile"; | |
f7da2de0 | 450 | } else |
898127c3 | 451 | error = -EACCES; |
898127c3 JJ |
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) { | |
c29bceb3 JJ |
462 | error = -EPERM; |
463 | goto cleanup; | |
464 | } | |
465 | ||
898127c3 JJ |
466 | if (!new_profile) |
467 | goto audit; | |
468 | ||
469 | if (bprm->unsafe & LSM_UNSAFE_SHARE) { | |
470 | /* FIXME: currently don't mediate shared state */ | |
471 | ; | |
472 | } | |
473 | ||
474 | if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { | |
51775fe7 | 475 | error = may_change_ptraced_domain(new_profile); |
f7da2de0 | 476 | if (error) |
898127c3 | 477 | goto audit; |
898127c3 JJ |
478 | } |
479 | ||
480 | /* Determine if secure exec is needed. | |
481 | * Can be at this point for the following reasons: | |
482 | * 1. unconfined switching to confined | |
483 | * 2. confined switching to different confinement | |
484 | * 3. confined switching to unconfined | |
485 | * | |
486 | * Cases 2 and 3 are marked as requiring secure exec | |
487 | * (unless policy specified "unsafe exec") | |
488 | * | |
489 | * bprm->unsafe is used to cache the AA_X_UNSAFE permission | |
490 | * to avoid having to recompute in secureexec | |
491 | */ | |
492 | if (!(perms.xindex & AA_X_UNSAFE)) { | |
493 | AA_DEBUG("scrubbing environment variables for %s profile=%s\n", | |
494 | name, new_profile->base.hname); | |
495 | bprm->unsafe |= AA_SECURE_X_NEEDED; | |
496 | } | |
497 | apply: | |
898127c3 JJ |
498 | /* when transitioning profiles clear unsafe personality bits */ |
499 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
500 | ||
501 | x_clear: | |
502 | aa_put_profile(cxt->profile); | |
503 | /* transfer new profile reference will be released when cxt is freed */ | |
504 | cxt->profile = new_profile; | |
f7da2de0 | 505 | new_profile = NULL; |
898127c3 JJ |
506 | |
507 | /* clear out all temporary/transitional state from the context */ | |
7a2871b5 | 508 | aa_clear_task_cxt_trans(cxt); |
898127c3 JJ |
509 | |
510 | audit: | |
511 | error = aa_audit_file(profile, &perms, GFP_KERNEL, OP_EXEC, MAY_EXEC, | |
f7da2de0 JJ |
512 | name, |
513 | new_profile ? new_profile->base.hname : NULL, | |
514 | cond.uid, info, error); | |
898127c3 JJ |
515 | |
516 | cleanup: | |
f7da2de0 | 517 | aa_put_profile(new_profile); |
898127c3 JJ |
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); |
3d40658c JJ |
626 | profile = aa_get_newest_profile(aa_cred_profile(cred)); |
627 | previous_profile = aa_get_newest_profile(cxt->previous); | |
898127c3 JJ |
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 */ | |
181f7c97 JJ |
671 | hat = aa_new_null_profile(profile, true, hats[0], |
672 | GFP_KERNEL); | |
898127c3 JJ |
673 | if (!hat) { |
674 | info = "failed null profile create"; | |
675 | error = -ENOMEM; | |
676 | goto audit; | |
677 | } | |
678 | } else { | |
01e2b670 | 679 | aa_put_profile(root); |
898127c3 JJ |
680 | target = hat->base.hname; |
681 | if (!PROFILE_IS_HAT(hat)) { | |
682 | info = "target not hat"; | |
683 | error = -EPERM; | |
684 | goto audit; | |
685 | } | |
686 | } | |
687 | ||
51775fe7 | 688 | error = may_change_ptraced_domain(hat); |
898127c3 JJ |
689 | if (error) { |
690 | info = "ptraced"; | |
691 | error = -EPERM; | |
692 | goto audit; | |
693 | } | |
694 | ||
695 | if (!permtest) { | |
696 | error = aa_set_current_hat(hat, token); | |
697 | if (error == -EACCES) | |
698 | /* kill task in case of brute force attacks */ | |
699 | perms.kill = AA_MAY_CHANGEHAT; | |
700 | else if (name && !error) | |
701 | /* reset error for learning of new hats */ | |
702 | error = -ENOENT; | |
703 | } | |
704 | } else if (previous_profile) { | |
705 | /* Return to saved profile. Kill task if restore fails | |
706 | * to avoid brute force attacks | |
707 | */ | |
708 | target = previous_profile->base.hname; | |
709 | error = aa_restore_previous_profile(token); | |
710 | perms.kill = AA_MAY_CHANGEHAT; | |
711 | } else | |
712 | /* ignore restores when there is no saved profile */ | |
713 | goto out; | |
714 | ||
715 | audit: | |
716 | if (!permtest) | |
717 | error = aa_audit_file(profile, &perms, GFP_KERNEL, | |
718 | OP_CHANGE_HAT, AA_MAY_CHANGEHAT, NULL, | |
2db81452 | 719 | target, GLOBAL_ROOT_UID, info, error); |
898127c3 JJ |
720 | |
721 | out: | |
722 | aa_put_profile(hat); | |
723 | kfree(name); | |
3d40658c JJ |
724 | aa_put_profile(profile); |
725 | aa_put_profile(previous_profile); | |
898127c3 JJ |
726 | put_cred(cred); |
727 | ||
728 | return error; | |
729 | } | |
730 | ||
731 | /** | |
732 | * aa_change_profile - perform a one-way profile transition | |
733 | * @ns_name: name of the profile namespace to change to (MAYBE NULL) | |
734 | * @hname: name of profile to change to (MAYBE NULL) | |
735 | * @onexec: whether this transition is to take place immediately or at exec | |
736 | * @permtest: true if this is just a permission test | |
737 | * | |
738 | * Change to new profile @name. Unlike with hats, there is no way | |
739 | * to change back. If @name isn't specified the current profile name is | |
740 | * used. | |
741 | * If @onexec then the transition is delayed until | |
742 | * the next exec. | |
743 | * | |
744 | * Returns %0 on success, error otherwise. | |
745 | */ | |
746 | int aa_change_profile(const char *ns_name, const char *hname, bool onexec, | |
747 | bool permtest) | |
748 | { | |
749 | const struct cred *cred; | |
898127c3 | 750 | struct aa_profile *profile, *target = NULL; |
98849dff | 751 | struct aa_ns *ns = NULL; |
898127c3 JJ |
752 | struct file_perms perms = {}; |
753 | const char *name = NULL, *info = NULL; | |
754 | int op, error = 0; | |
755 | u32 request; | |
756 | ||
757 | if (!hname && !ns_name) | |
758 | return -EINVAL; | |
759 | ||
760 | if (onexec) { | |
761 | request = AA_MAY_ONEXEC; | |
762 | op = OP_CHANGE_ONEXEC; | |
763 | } else { | |
764 | request = AA_MAY_CHANGE_PROFILE; | |
765 | op = OP_CHANGE_PROFILE; | |
766 | } | |
767 | ||
768 | cred = get_current_cred(); | |
898127c3 JJ |
769 | profile = aa_cred_profile(cred); |
770 | ||
c29bceb3 JJ |
771 | /* |
772 | * Fail explicitly requested domain transitions if no_new_privs | |
773 | * and not unconfined. | |
774 | * Domain transitions from unconfined are allowed even when | |
775 | * no_new_privs is set because this aways results in a reduction | |
776 | * of permissions. | |
777 | */ | |
1d4457f9 | 778 | if (task_no_new_privs(current) && !unconfined(profile)) { |
c29bceb3 JJ |
779 | put_cred(cred); |
780 | return -EPERM; | |
781 | } | |
782 | ||
898127c3 JJ |
783 | if (ns_name) { |
784 | /* released below */ | |
98849dff | 785 | ns = aa_find_ns(profile->ns, ns_name); |
898127c3 JJ |
786 | if (!ns) { |
787 | /* we don't create new namespace in complain mode */ | |
788 | name = ns_name; | |
789 | info = "namespace not found"; | |
790 | error = -ENOENT; | |
791 | goto audit; | |
792 | } | |
793 | } else | |
794 | /* released below */ | |
98849dff | 795 | ns = aa_get_ns(profile->ns); |
898127c3 JJ |
796 | |
797 | /* if the name was not specified, use the name of the current profile */ | |
798 | if (!hname) { | |
799 | if (unconfined(profile)) | |
800 | hname = ns->unconfined->base.hname; | |
801 | else | |
802 | hname = profile->base.hname; | |
803 | } | |
804 | ||
805 | perms = change_profile_perms(profile, ns, hname, request, | |
806 | profile->file.start); | |
807 | if (!(perms.allow & request)) { | |
808 | error = -EACCES; | |
809 | goto audit; | |
810 | } | |
811 | ||
812 | /* released below */ | |
813 | target = aa_lookup_profile(ns, hname); | |
814 | if (!target) { | |
815 | info = "profile not found"; | |
816 | error = -ENOENT; | |
817 | if (permtest || !COMPLAIN_MODE(profile)) | |
818 | goto audit; | |
819 | /* released below */ | |
181f7c97 | 820 | target = aa_new_null_profile(profile, false, hname, GFP_KERNEL); |
898127c3 JJ |
821 | if (!target) { |
822 | info = "failed null profile create"; | |
823 | error = -ENOMEM; | |
824 | goto audit; | |
825 | } | |
826 | } | |
827 | ||
828 | /* check if tracing task is allowed to trace target domain */ | |
51775fe7 | 829 | error = may_change_ptraced_domain(target); |
898127c3 JJ |
830 | if (error) { |
831 | info = "ptrace prevents transition"; | |
832 | goto audit; | |
833 | } | |
834 | ||
835 | if (permtest) | |
836 | goto audit; | |
837 | ||
838 | if (onexec) | |
839 | error = aa_set_current_onexec(target); | |
840 | else | |
841 | error = aa_replace_current_profile(target); | |
842 | ||
843 | audit: | |
844 | if (!permtest) | |
845 | error = aa_audit_file(profile, &perms, GFP_KERNEL, op, request, | |
2db81452 | 846 | name, hname, GLOBAL_ROOT_UID, info, error); |
898127c3 | 847 | |
98849dff | 848 | aa_put_ns(ns); |
898127c3 JJ |
849 | aa_put_profile(target); |
850 | put_cred(cred); | |
851 | ||
852 | return error; | |
853 | } |