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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 | |
b2d09ae4 JJ |
54 | * @to_label: profile to change to (NOT NULL) |
55 | * @info: message if there is an error | |
898127c3 | 56 | * |
51775fe7 | 57 | * Check if current is ptraced and if so if the tracing task is allowed |
898127c3 JJ |
58 | * to trace the new domain |
59 | * | |
60 | * Returns: %0 or error if change not allowed | |
61 | */ | |
b2d09ae4 JJ |
62 | static int may_change_ptraced_domain(struct aa_label *to_label, |
63 | const char **info) | |
898127c3 JJ |
64 | { |
65 | struct task_struct *tracer; | |
637f688d | 66 | struct aa_label *tracerl = NULL; |
898127c3 JJ |
67 | int error = 0; |
68 | ||
69 | rcu_read_lock(); | |
51775fe7 | 70 | tracer = ptrace_parent(current); |
3cfcc19e | 71 | if (tracer) |
898127c3 | 72 | /* released below */ |
637f688d | 73 | tracerl = aa_get_task_label(tracer); |
898127c3 JJ |
74 | |
75 | /* not ptraced */ | |
637f688d | 76 | if (!tracer || unconfined(tracerl)) |
898127c3 JJ |
77 | goto out; |
78 | ||
b2d09ae4 | 79 | error = aa_may_ptrace(tracerl, to_label, PTRACE_MODE_ATTACH); |
898127c3 JJ |
80 | |
81 | out: | |
04fdc099 | 82 | rcu_read_unlock(); |
637f688d | 83 | aa_put_label(tracerl); |
898127c3 | 84 | |
b2d09ae4 JJ |
85 | if (error) |
86 | *info = "ptrace prevents transition"; | |
898127c3 JJ |
87 | return error; |
88 | } | |
89 | ||
90 | /** | |
91 | * change_profile_perms - find permissions for change_profile | |
92 | * @profile: the current profile (NOT NULL) | |
93 | * @ns: the namespace being switched to (NOT NULL) | |
94 | * @name: the name of the profile to change to (NOT NULL) | |
95 | * @request: requested perms | |
96 | * @start: state to start matching in | |
97 | * | |
98 | * Returns: permission set | |
99 | */ | |
2d679f3c JJ |
100 | static struct aa_perms change_profile_perms(struct aa_profile *profile, |
101 | struct aa_ns *ns, | |
102 | const char *name, u32 request, | |
103 | unsigned int start) | |
898127c3 | 104 | { |
2d679f3c | 105 | struct aa_perms perms; |
898127c3 JJ |
106 | struct path_cond cond = { }; |
107 | unsigned int state; | |
108 | ||
637f688d | 109 | if (profile_unconfined(profile)) { |
898127c3 JJ |
110 | perms.allow = AA_MAY_CHANGE_PROFILE | AA_MAY_ONEXEC; |
111 | perms.audit = perms.quiet = perms.kill = 0; | |
112 | return perms; | |
113 | } else if (!profile->file.dfa) { | |
114 | return nullperms; | |
115 | } else if ((ns == profile->ns)) { | |
116 | /* try matching against rules with out namespace prepended */ | |
117 | aa_str_perms(profile->file.dfa, start, name, &cond, &perms); | |
118 | if (COMBINED_PERM_MASK(perms) & request) | |
119 | return perms; | |
120 | } | |
121 | ||
122 | /* try matching with namespace name and then profile */ | |
123 | state = aa_dfa_match(profile->file.dfa, start, ns->base.name); | |
124 | state = aa_dfa_match_len(profile->file.dfa, state, ":", 1); | |
125 | aa_str_perms(profile->file.dfa, state, name, &cond, &perms); | |
126 | ||
127 | return perms; | |
128 | } | |
129 | ||
130 | /** | |
131 | * __attach_match_ - find an attachment match | |
132 | * @name - to match against (NOT NULL) | |
133 | * @head - profile list to walk (NOT NULL) | |
134 | * | |
135 | * Do a linear search on the profiles in the list. There is a matching | |
136 | * preference where an exact match is preferred over a name which uses | |
137 | * expressions to match, and matching expressions with the greatest | |
138 | * xmatch_len are preferred. | |
139 | * | |
140 | * Requires: @head not be shared or have appropriate locks held | |
141 | * | |
142 | * Returns: profile or NULL if no match found | |
143 | */ | |
144 | static struct aa_profile *__attach_match(const char *name, | |
145 | struct list_head *head) | |
146 | { | |
147 | int len = 0; | |
148 | struct aa_profile *profile, *candidate = NULL; | |
149 | ||
01e2b670 | 150 | list_for_each_entry_rcu(profile, head, base.list) { |
637f688d | 151 | if (profile->label.flags & FLAG_NULL) |
898127c3 JJ |
152 | continue; |
153 | if (profile->xmatch && profile->xmatch_len > len) { | |
154 | unsigned int state = aa_dfa_match(profile->xmatch, | |
155 | DFA_START, name); | |
156 | u32 perm = dfa_user_allow(profile->xmatch, state); | |
157 | /* any accepting state means a valid match. */ | |
158 | if (perm & MAY_EXEC) { | |
159 | candidate = profile; | |
160 | len = profile->xmatch_len; | |
161 | } | |
162 | } else if (!strcmp(profile->base.name, name)) | |
163 | /* exact non-re match, no more searching required */ | |
164 | return profile; | |
165 | } | |
166 | ||
167 | return candidate; | |
168 | } | |
169 | ||
170 | /** | |
171 | * find_attach - do attachment search for unconfined processes | |
172 | * @ns: the current namespace (NOT NULL) | |
173 | * @list: list to search (NOT NULL) | |
174 | * @name: the executable name to match against (NOT NULL) | |
175 | * | |
176 | * Returns: profile or NULL if no match found | |
177 | */ | |
98849dff | 178 | static struct aa_profile *find_attach(struct aa_ns *ns, |
898127c3 JJ |
179 | struct list_head *list, const char *name) |
180 | { | |
181 | struct aa_profile *profile; | |
182 | ||
01e2b670 | 183 | rcu_read_lock(); |
898127c3 | 184 | profile = aa_get_profile(__attach_match(name, list)); |
01e2b670 | 185 | rcu_read_unlock(); |
898127c3 JJ |
186 | |
187 | return profile; | |
188 | } | |
189 | ||
190 | /** | |
191 | * separate_fqname - separate the namespace and profile names | |
192 | * @fqname: the fqname name to split (NOT NULL) | |
193 | * @ns_name: the namespace name if it exists (NOT NULL) | |
194 | * | |
195 | * This is the xtable equivalent routine of aa_split_fqname. It finds the | |
196 | * split in an xtable fqname which contains an embedded \0 instead of a : | |
197 | * if a namespace is specified. This is done so the xtable is constant and | |
198 | * isn't re-split on every lookup. | |
199 | * | |
200 | * Either the profile or namespace name may be optional but if the namespace | |
201 | * is specified the profile name termination must be present. This results | |
202 | * in the following possible encodings: | |
203 | * profile_name\0 | |
204 | * :ns_name\0profile_name\0 | |
205 | * :ns_name\0\0 | |
206 | * | |
207 | * NOTE: the xtable fqname is pre-validated at load time in unpack_trans_table | |
208 | * | |
209 | * Returns: profile name if it is specified else NULL | |
210 | */ | |
211 | static const char *separate_fqname(const char *fqname, const char **ns_name) | |
212 | { | |
213 | const char *name; | |
214 | ||
215 | if (fqname[0] == ':') { | |
216 | /* In this case there is guaranteed to be two \0 terminators | |
217 | * in the string. They are verified at load time by | |
218 | * by unpack_trans_table | |
219 | */ | |
220 | *ns_name = fqname + 1; /* skip : */ | |
221 | name = *ns_name + strlen(*ns_name) + 1; | |
222 | if (!*name) | |
223 | name = NULL; | |
224 | } else { | |
225 | *ns_name = NULL; | |
226 | name = fqname; | |
227 | } | |
228 | ||
229 | return name; | |
230 | } | |
231 | ||
232 | static const char *next_name(int xtype, const char *name) | |
233 | { | |
234 | return NULL; | |
235 | } | |
236 | ||
237 | /** | |
238 | * x_table_lookup - lookup an x transition name via transition table | |
239 | * @profile: current profile (NOT NULL) | |
240 | * @xindex: index into x transition table | |
241 | * | |
242 | * Returns: refcounted profile, or NULL on failure (MAYBE NULL) | |
243 | */ | |
244 | static struct aa_profile *x_table_lookup(struct aa_profile *profile, u32 xindex) | |
245 | { | |
246 | struct aa_profile *new_profile = NULL; | |
98849dff | 247 | struct aa_ns *ns = profile->ns; |
898127c3 JJ |
248 | u32 xtype = xindex & AA_X_TYPE_MASK; |
249 | int index = xindex & AA_X_INDEX_MASK; | |
250 | const char *name; | |
251 | ||
252 | /* index is guaranteed to be in range, validated at load time */ | |
253 | for (name = profile->file.trans.table[index]; !new_profile && name; | |
254 | name = next_name(xtype, name)) { | |
98849dff | 255 | struct aa_ns *new_ns; |
898127c3 JJ |
256 | const char *xname = NULL; |
257 | ||
258 | new_ns = NULL; | |
259 | if (xindex & AA_X_CHILD) { | |
260 | /* release by caller */ | |
261 | new_profile = aa_find_child(profile, name); | |
262 | continue; | |
263 | } else if (*name == ':') { | |
264 | /* switching namespace */ | |
265 | const char *ns_name; | |
266 | xname = name = separate_fqname(name, &ns_name); | |
267 | if (!xname) | |
268 | /* no name so use profile name */ | |
269 | xname = profile->base.hname; | |
270 | if (*ns_name == '@') { | |
271 | /* TODO: variable support */ | |
272 | ; | |
273 | } | |
274 | /* released below */ | |
98849dff | 275 | new_ns = aa_find_ns(ns, ns_name); |
898127c3 JJ |
276 | if (!new_ns) |
277 | continue; | |
278 | } else if (*name == '@') { | |
279 | /* TODO: variable support */ | |
280 | continue; | |
281 | } else { | |
282 | /* basic namespace lookup */ | |
283 | xname = name; | |
284 | } | |
285 | ||
286 | /* released by caller */ | |
287 | new_profile = aa_lookup_profile(new_ns ? new_ns : ns, xname); | |
98849dff | 288 | aa_put_ns(new_ns); |
898127c3 JJ |
289 | } |
290 | ||
291 | /* released by caller */ | |
292 | return new_profile; | |
293 | } | |
294 | ||
295 | /** | |
296 | * x_to_profile - get target profile for a given xindex | |
297 | * @profile: current profile (NOT NULL) | |
298 | * @name: name to lookup (NOT NULL) | |
299 | * @xindex: index into x transition table | |
300 | * | |
301 | * find profile for a transition index | |
302 | * | |
303 | * Returns: refcounted profile or NULL if not found available | |
304 | */ | |
305 | static struct aa_profile *x_to_profile(struct aa_profile *profile, | |
306 | const char *name, u32 xindex) | |
307 | { | |
308 | struct aa_profile *new_profile = NULL; | |
98849dff | 309 | struct aa_ns *ns = profile->ns; |
898127c3 JJ |
310 | u32 xtype = xindex & AA_X_TYPE_MASK; |
311 | ||
312 | switch (xtype) { | |
313 | case AA_X_NONE: | |
314 | /* fail exec unless ix || ux fallback - handled by caller */ | |
315 | return NULL; | |
316 | case AA_X_NAME: | |
317 | if (xindex & AA_X_CHILD) | |
318 | /* released by caller */ | |
319 | new_profile = find_attach(ns, &profile->base.profiles, | |
320 | name); | |
321 | else | |
322 | /* released by caller */ | |
323 | new_profile = find_attach(ns, &ns->base.profiles, | |
324 | name); | |
325 | break; | |
326 | case AA_X_TABLE: | |
327 | /* released by caller */ | |
328 | new_profile = x_table_lookup(profile, xindex); | |
329 | break; | |
330 | } | |
331 | ||
332 | /* released by caller */ | |
333 | return new_profile; | |
334 | } | |
335 | ||
336 | /** | |
337 | * apparmor_bprm_set_creds - set the new creds on the bprm struct | |
338 | * @bprm: binprm for the exec (NOT NULL) | |
339 | * | |
340 | * Returns: %0 or error on failure | |
341 | */ | |
342 | int apparmor_bprm_set_creds(struct linux_binprm *bprm) | |
343 | { | |
55a26ebf | 344 | struct aa_task_ctx *ctx; |
637f688d | 345 | struct aa_label *label; |
898127c3 | 346 | struct aa_profile *profile, *new_profile = NULL; |
98849dff | 347 | struct aa_ns *ns; |
898127c3 JJ |
348 | char *buffer = NULL; |
349 | unsigned int state; | |
2d679f3c | 350 | struct aa_perms perms = {}; |
898127c3 | 351 | struct path_cond cond = { |
496ad9aa AV |
352 | file_inode(bprm->file)->i_uid, |
353 | file_inode(bprm->file)->i_mode | |
898127c3 | 354 | }; |
f7da2de0 | 355 | const char *name = NULL, *info = NULL; |
b1d9e6b0 | 356 | int error = 0; |
898127c3 JJ |
357 | |
358 | if (bprm->cred_prepared) | |
359 | return 0; | |
360 | ||
55a26ebf JJ |
361 | ctx = cred_ctx(bprm->cred); |
362 | AA_BUG(!ctx); | |
898127c3 | 363 | |
637f688d JJ |
364 | label = aa_get_newest_label(ctx->label); |
365 | profile = labels_profile(label); | |
4227c333 JJ |
366 | |
367 | /* buffer freed below, name is pointer into buffer */ | |
368 | get_buffers(buffer); | |
898127c3 JJ |
369 | /* |
370 | * get the namespace from the replacement profile as replacement | |
371 | * can change the namespace | |
372 | */ | |
373 | ns = profile->ns; | |
374 | state = profile->file.start; | |
375 | ||
4227c333 | 376 | error = aa_path_name(&bprm->file->f_path, profile->path_flags, buffer, |
72c8a768 | 377 | &name, &info, profile->disconnected); |
898127c3 | 378 | if (error) { |
637f688d JJ |
379 | if (profile_unconfined(profile) || |
380 | (profile->label.flags & FLAG_IX_ON_NAME_ERROR)) | |
898127c3 | 381 | error = 0; |
898127c3 JJ |
382 | name = bprm->filename; |
383 | goto audit; | |
384 | } | |
385 | ||
386 | /* Test for onexec first as onexec directives override other | |
387 | * x transitions. | |
388 | */ | |
637f688d | 389 | if (profile_unconfined(profile)) { |
898127c3 | 390 | /* unconfined task */ |
55a26ebf | 391 | if (ctx->onexec) |
898127c3 | 392 | /* change_profile on exec already been granted */ |
637f688d | 393 | new_profile = labels_profile(aa_get_label(ctx->onexec)); |
898127c3 JJ |
394 | else |
395 | new_profile = find_attach(ns, &ns->base.profiles, name); | |
396 | if (!new_profile) | |
397 | goto cleanup; | |
c29bceb3 JJ |
398 | /* |
399 | * NOTE: Domain transitions from unconfined are allowed | |
400 | * even when no_new_privs is set because this aways results | |
401 | * in a further reduction of permissions. | |
402 | */ | |
898127c3 JJ |
403 | goto apply; |
404 | } | |
405 | ||
406 | /* find exec permissions for name */ | |
407 | state = aa_str_perms(profile->file.dfa, state, name, &cond, &perms); | |
55a26ebf | 408 | if (ctx->onexec) { |
2d679f3c | 409 | struct aa_perms cp; |
898127c3 | 410 | info = "change_profile onexec"; |
637f688d | 411 | new_profile = labels_profile(aa_get_newest_label(ctx->onexec)); |
898127c3 JJ |
412 | if (!(perms.allow & AA_MAY_ONEXEC)) |
413 | goto audit; | |
414 | ||
415 | /* test if this exec can be paired with change_profile onexec. | |
416 | * onexec permission is linked to exec with a standard pairing | |
417 | * exec\0change_profile | |
418 | */ | |
419 | state = aa_dfa_null_transition(profile->file.dfa, state); | |
637f688d JJ |
420 | cp = change_profile_perms(profile, labels_ns(ctx->onexec), |
421 | labels_profile(ctx->onexec)->base.name, | |
422 | AA_MAY_ONEXEC, state); | |
898127c3 JJ |
423 | |
424 | if (!(cp.allow & AA_MAY_ONEXEC)) | |
425 | goto audit; | |
898127c3 JJ |
426 | goto apply; |
427 | } | |
428 | ||
429 | if (perms.allow & MAY_EXEC) { | |
430 | /* exec permission determine how to transition */ | |
431 | new_profile = x_to_profile(profile, name, perms.xindex); | |
432 | if (!new_profile) { | |
433 | if (perms.xindex & AA_X_INHERIT) { | |
434 | /* (p|c|n)ix - don't change profile but do | |
435 | * use the newest version, which was picked | |
436 | * up above when getting profile | |
437 | */ | |
438 | info = "ix fallback"; | |
439 | new_profile = aa_get_profile(profile); | |
440 | goto x_clear; | |
441 | } else if (perms.xindex & AA_X_UNCONFINED) { | |
fa2ac468 | 442 | new_profile = aa_get_newest_profile(ns->unconfined); |
898127c3 JJ |
443 | info = "ux fallback"; |
444 | } else { | |
9049a792 | 445 | error = -EACCES; |
898127c3 | 446 | info = "profile not found"; |
17322cc3 JJ |
447 | /* remove MAY_EXEC to audit as failure */ |
448 | perms.allow &= ~MAY_EXEC; | |
898127c3 JJ |
449 | } |
450 | } | |
451 | } else if (COMPLAIN_MODE(profile)) { | |
452 | /* no exec permission - are we in learning mode */ | |
181f7c97 JJ |
453 | new_profile = aa_new_null_profile(profile, false, name, |
454 | GFP_ATOMIC); | |
898127c3 JJ |
455 | if (!new_profile) { |
456 | error = -ENOMEM; | |
457 | info = "could not create null profile"; | |
f7da2de0 | 458 | } else |
898127c3 | 459 | error = -EACCES; |
898127c3 JJ |
460 | perms.xindex |= AA_X_UNSAFE; |
461 | } else | |
462 | /* fail exec */ | |
463 | error = -EACCES; | |
464 | ||
c29bceb3 JJ |
465 | /* |
466 | * Policy has specified a domain transition, if no_new_privs then | |
467 | * fail the exec. | |
468 | */ | |
469 | if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) { | |
c29bceb3 JJ |
470 | error = -EPERM; |
471 | goto cleanup; | |
472 | } | |
473 | ||
898127c3 JJ |
474 | if (!new_profile) |
475 | goto audit; | |
476 | ||
477 | if (bprm->unsafe & LSM_UNSAFE_SHARE) { | |
478 | /* FIXME: currently don't mediate shared state */ | |
479 | ; | |
480 | } | |
481 | ||
9227dd2a | 482 | if (bprm->unsafe & LSM_UNSAFE_PTRACE) { |
b2d09ae4 | 483 | error = may_change_ptraced_domain(&new_profile->label, &info); |
f7da2de0 | 484 | if (error) |
898127c3 | 485 | goto audit; |
898127c3 JJ |
486 | } |
487 | ||
488 | /* Determine if secure exec is needed. | |
489 | * Can be at this point for the following reasons: | |
490 | * 1. unconfined switching to confined | |
491 | * 2. confined switching to different confinement | |
492 | * 3. confined switching to unconfined | |
493 | * | |
494 | * Cases 2 and 3 are marked as requiring secure exec | |
495 | * (unless policy specified "unsafe exec") | |
496 | * | |
497 | * bprm->unsafe is used to cache the AA_X_UNSAFE permission | |
498 | * to avoid having to recompute in secureexec | |
499 | */ | |
500 | if (!(perms.xindex & AA_X_UNSAFE)) { | |
501 | AA_DEBUG("scrubbing environment variables for %s profile=%s\n", | |
502 | name, new_profile->base.hname); | |
503 | bprm->unsafe |= AA_SECURE_X_NEEDED; | |
504 | } | |
505 | apply: | |
898127c3 JJ |
506 | /* when transitioning profiles clear unsafe personality bits */ |
507 | bprm->per_clear |= PER_CLEAR_ON_SETID; | |
508 | ||
509 | x_clear: | |
637f688d | 510 | aa_put_label(ctx->label); |
55a26ebf | 511 | /* transfer new profile reference will be released when ctx is freed */ |
637f688d | 512 | ctx->label = &new_profile->label; |
f7da2de0 | 513 | new_profile = NULL; |
898127c3 JJ |
514 | |
515 | /* clear out all temporary/transitional state from the context */ | |
55a26ebf | 516 | aa_clear_task_ctx_trans(ctx); |
898127c3 JJ |
517 | |
518 | audit: | |
ef88a7ac | 519 | error = aa_audit_file(profile, &perms, OP_EXEC, MAY_EXEC, name, |
f7da2de0 | 520 | new_profile ? new_profile->base.hname : NULL, |
98c3d182 | 521 | new_profile ? &new_profile->label : NULL, |
f7da2de0 | 522 | cond.uid, info, error); |
898127c3 JJ |
523 | |
524 | cleanup: | |
f7da2de0 | 525 | aa_put_profile(new_profile); |
637f688d | 526 | aa_put_label(label); |
4227c333 | 527 | put_buffers(buffer); |
898127c3 JJ |
528 | |
529 | return error; | |
530 | } | |
531 | ||
532 | /** | |
533 | * apparmor_bprm_secureexec - determine if secureexec is needed | |
534 | * @bprm: binprm for exec (NOT NULL) | |
535 | * | |
536 | * Returns: %1 if secureexec is needed else %0 | |
537 | */ | |
538 | int apparmor_bprm_secureexec(struct linux_binprm *bprm) | |
539 | { | |
898127c3 JJ |
540 | /* the decision to use secure exec is computed in set_creds |
541 | * and stored in bprm->unsafe. | |
542 | */ | |
b1d9e6b0 CS |
543 | if (bprm->unsafe & AA_SECURE_X_NEEDED) |
544 | return 1; | |
898127c3 | 545 | |
b1d9e6b0 | 546 | return 0; |
898127c3 JJ |
547 | } |
548 | ||
898127c3 JJ |
549 | /* |
550 | * Functions for self directed profile change | |
551 | */ | |
552 | ||
553 | /** | |
554 | * new_compound_name - create an hname with @n2 appended to @n1 | |
555 | * @n1: base of hname (NOT NULL) | |
556 | * @n2: name to append (NOT NULL) | |
557 | * | |
558 | * Returns: new name or NULL on error | |
559 | */ | |
560 | static char *new_compound_name(const char *n1, const char *n2) | |
561 | { | |
562 | char *name = kmalloc(strlen(n1) + strlen(n2) + 3, GFP_KERNEL); | |
563 | if (name) | |
564 | sprintf(name, "%s//%s", n1, n2); | |
565 | return name; | |
566 | } | |
567 | ||
568 | /** | |
569 | * aa_change_hat - change hat to/from subprofile | |
570 | * @hats: vector of hat names to try changing into (MAYBE NULL if @count == 0) | |
571 | * @count: number of hat names in @hats | |
572 | * @token: magic value to validate the hat change | |
df8073c6 | 573 | * @flags: flags affecting behavior of the change |
898127c3 JJ |
574 | * |
575 | * Change to the first profile specified in @hats that exists, and store | |
576 | * the @hat_magic in the current task context. If the count == 0 and the | |
577 | * @token matches that stored in the current task context, return to the | |
578 | * top level profile. | |
579 | * | |
580 | * Returns %0 on success, error otherwise. | |
581 | */ | |
df8073c6 | 582 | int aa_change_hat(const char *hats[], int count, u64 token, int flags) |
898127c3 JJ |
583 | { |
584 | const struct cred *cred; | |
55a26ebf | 585 | struct aa_task_ctx *ctx; |
637f688d JJ |
586 | struct aa_label *label, *previous_label; |
587 | struct aa_profile *profile, *hat = NULL; | |
898127c3 JJ |
588 | char *name = NULL; |
589 | int i; | |
2d679f3c | 590 | struct aa_perms perms = {}; |
898127c3 JJ |
591 | const char *target = NULL, *info = NULL; |
592 | int error = 0; | |
593 | ||
c29bceb3 JJ |
594 | /* |
595 | * Fail explicitly requested domain transitions if no_new_privs. | |
596 | * There is no exception for unconfined as change_hat is not | |
597 | * available. | |
598 | */ | |
1d4457f9 | 599 | if (task_no_new_privs(current)) |
c29bceb3 JJ |
600 | return -EPERM; |
601 | ||
898127c3 JJ |
602 | /* released below */ |
603 | cred = get_current_cred(); | |
55a26ebf | 604 | ctx = cred_ctx(cred); |
637f688d JJ |
605 | label = aa_get_newest_cred_label(cred); |
606 | previous_label = aa_get_newest_label(ctx->previous); | |
607 | profile = labels_profile(label); | |
898127c3 | 608 | |
637f688d | 609 | if (unconfined(label)) { |
898127c3 JJ |
610 | info = "unconfined"; |
611 | error = -EPERM; | |
612 | goto audit; | |
613 | } | |
614 | ||
615 | if (count) { | |
616 | /* attempting to change into a new hat or switch to a sibling */ | |
617 | struct aa_profile *root; | |
01e2b670 JJ |
618 | if (PROFILE_IS_HAT(profile)) |
619 | root = aa_get_profile_rcu(&profile->parent); | |
620 | else | |
621 | root = aa_get_profile(profile); | |
898127c3 JJ |
622 | |
623 | /* find first matching hat */ | |
624 | for (i = 0; i < count && !hat; i++) | |
625 | /* released below */ | |
626 | hat = aa_find_child(root, hats[i]); | |
627 | if (!hat) { | |
df8073c6 | 628 | if (!COMPLAIN_MODE(root) || (flags & AA_CHANGE_TEST)) { |
898127c3 JJ |
629 | if (list_empty(&root->base.profiles)) |
630 | error = -ECHILD; | |
631 | else | |
632 | error = -ENOENT; | |
01e2b670 | 633 | aa_put_profile(root); |
898127c3 JJ |
634 | goto out; |
635 | } | |
636 | ||
637 | /* | |
638 | * In complain mode and failed to match any hats. | |
639 | * Audit the failure is based off of the first hat | |
640 | * supplied. This is done due how userspace | |
641 | * interacts with change_hat. | |
642 | * | |
643 | * TODO: Add logging of all failed hats | |
644 | */ | |
645 | ||
646 | /* freed below */ | |
647 | name = new_compound_name(root->base.hname, hats[0]); | |
01e2b670 | 648 | aa_put_profile(root); |
898127c3 JJ |
649 | target = name; |
650 | /* released below */ | |
181f7c97 JJ |
651 | hat = aa_new_null_profile(profile, true, hats[0], |
652 | GFP_KERNEL); | |
898127c3 JJ |
653 | if (!hat) { |
654 | info = "failed null profile create"; | |
655 | error = -ENOMEM; | |
656 | goto audit; | |
657 | } | |
658 | } else { | |
01e2b670 | 659 | aa_put_profile(root); |
898127c3 JJ |
660 | target = hat->base.hname; |
661 | if (!PROFILE_IS_HAT(hat)) { | |
662 | info = "target not hat"; | |
663 | error = -EPERM; | |
664 | goto audit; | |
665 | } | |
666 | } | |
667 | ||
b2d09ae4 | 668 | error = may_change_ptraced_domain(&hat->label, &info); |
898127c3 JJ |
669 | if (error) { |
670 | info = "ptraced"; | |
671 | error = -EPERM; | |
672 | goto audit; | |
673 | } | |
674 | ||
df8073c6 | 675 | if (!(flags & AA_CHANGE_TEST)) { |
637f688d | 676 | error = aa_set_current_hat(&hat->label, token); |
898127c3 JJ |
677 | if (error == -EACCES) |
678 | /* kill task in case of brute force attacks */ | |
679 | perms.kill = AA_MAY_CHANGEHAT; | |
680 | else if (name && !error) | |
681 | /* reset error for learning of new hats */ | |
682 | error = -ENOENT; | |
683 | } | |
637f688d | 684 | } else if (previous_label) { |
898127c3 JJ |
685 | /* Return to saved profile. Kill task if restore fails |
686 | * to avoid brute force attacks | |
687 | */ | |
637f688d JJ |
688 | target = previous_label->hname; |
689 | error = aa_restore_previous_label(token); | |
898127c3 JJ |
690 | perms.kill = AA_MAY_CHANGEHAT; |
691 | } else | |
692 | /* ignore restores when there is no saved profile */ | |
693 | goto out; | |
694 | ||
695 | audit: | |
df8073c6 | 696 | if (!(flags & AA_CHANGE_TEST)) |
ef88a7ac | 697 | error = aa_audit_file(profile, &perms, OP_CHANGE_HAT, |
98c3d182 | 698 | AA_MAY_CHANGEHAT, NULL, target, NULL, |
ef88a7ac | 699 | GLOBAL_ROOT_UID, info, error); |
898127c3 JJ |
700 | |
701 | out: | |
702 | aa_put_profile(hat); | |
703 | kfree(name); | |
637f688d JJ |
704 | aa_put_label(label); |
705 | aa_put_label(previous_label); | |
898127c3 JJ |
706 | put_cred(cred); |
707 | ||
708 | return error; | |
709 | } | |
710 | ||
711 | /** | |
712 | * aa_change_profile - perform a one-way profile transition | |
aa9a39ad | 713 | * @fqname: name of profile may include namespace (NOT NULL) |
898127c3 | 714 | * @onexec: whether this transition is to take place immediately or at exec |
df8073c6 | 715 | * @flags: flags affecting change behavior |
898127c3 JJ |
716 | * |
717 | * Change to new profile @name. Unlike with hats, there is no way | |
718 | * to change back. If @name isn't specified the current profile name is | |
719 | * used. | |
720 | * If @onexec then the transition is delayed until | |
721 | * the next exec. | |
722 | * | |
723 | * Returns %0 on success, error otherwise. | |
724 | */ | |
df8073c6 | 725 | int aa_change_profile(const char *fqname, int flags) |
898127c3 JJ |
726 | { |
727 | const struct cred *cred; | |
637f688d | 728 | struct aa_label *label; |
898127c3 | 729 | struct aa_profile *profile, *target = NULL; |
2d679f3c | 730 | struct aa_perms perms = {}; |
aa9a39ad | 731 | const char *info = NULL, *op; |
47f6e5cc | 732 | int error = 0; |
898127c3 JJ |
733 | u32 request; |
734 | ||
aa9a39ad JJ |
735 | if (!fqname || !*fqname) { |
736 | AA_DEBUG("no profile name"); | |
898127c3 | 737 | return -EINVAL; |
aa9a39ad | 738 | } |
898127c3 | 739 | |
df8073c6 | 740 | if (flags & AA_CHANGE_ONEXEC) { |
898127c3 JJ |
741 | request = AA_MAY_ONEXEC; |
742 | op = OP_CHANGE_ONEXEC; | |
743 | } else { | |
744 | request = AA_MAY_CHANGE_PROFILE; | |
745 | op = OP_CHANGE_PROFILE; | |
746 | } | |
747 | ||
748 | cred = get_current_cred(); | |
637f688d JJ |
749 | label = aa_get_newest_cred_label(cred); |
750 | profile = labels_profile(label); | |
898127c3 | 751 | |
c29bceb3 JJ |
752 | /* |
753 | * Fail explicitly requested domain transitions if no_new_privs | |
754 | * and not unconfined. | |
755 | * Domain transitions from unconfined are allowed even when | |
756 | * no_new_privs is set because this aways results in a reduction | |
757 | * of permissions. | |
758 | */ | |
637f688d | 759 | if (task_no_new_privs(current) && !profile_unconfined(profile)) { |
c29bceb3 JJ |
760 | put_cred(cred); |
761 | return -EPERM; | |
762 | } | |
763 | ||
637f688d | 764 | target = aa_fqlookupn_profile(label, fqname, strlen(fqname)); |
898127c3 JJ |
765 | if (!target) { |
766 | info = "profile not found"; | |
767 | error = -ENOENT; | |
df8073c6 JJ |
768 | if ((flags & AA_CHANGE_TEST) || |
769 | !COMPLAIN_MODE(profile)) | |
898127c3 JJ |
770 | goto audit; |
771 | /* released below */ | |
aa9a39ad JJ |
772 | target = aa_new_null_profile(profile, false, fqname, |
773 | GFP_KERNEL); | |
898127c3 JJ |
774 | if (!target) { |
775 | info = "failed null profile create"; | |
776 | error = -ENOMEM; | |
777 | goto audit; | |
778 | } | |
779 | } | |
780 | ||
aa9a39ad JJ |
781 | perms = change_profile_perms(profile, target->ns, target->base.hname, |
782 | request, profile->file.start); | |
783 | if (!(perms.allow & request)) { | |
784 | error = -EACCES; | |
785 | goto audit; | |
786 | } | |
787 | ||
898127c3 | 788 | /* check if tracing task is allowed to trace target domain */ |
b2d09ae4 | 789 | error = may_change_ptraced_domain(&target->label, &info); |
898127c3 JJ |
790 | if (error) { |
791 | info = "ptrace prevents transition"; | |
792 | goto audit; | |
793 | } | |
794 | ||
df8073c6 | 795 | if (flags & AA_CHANGE_TEST) |
898127c3 JJ |
796 | goto audit; |
797 | ||
df8073c6 | 798 | if (flags & AA_CHANGE_ONEXEC) |
637f688d | 799 | error = aa_set_current_onexec(&target->label, 0); |
898127c3 | 800 | else |
637f688d | 801 | error = aa_replace_current_label(&target->label); |
898127c3 JJ |
802 | |
803 | audit: | |
df8073c6 | 804 | if (!(flags & AA_CHANGE_TEST)) |
aa9a39ad | 805 | error = aa_audit_file(profile, &perms, op, request, NULL, |
98c3d182 JJ |
806 | fqname, NULL, GLOBAL_ROOT_UID, info, |
807 | error); | |
898127c3 | 808 | |
898127c3 | 809 | aa_put_profile(target); |
637f688d | 810 | aa_put_label(label); |
898127c3 JJ |
811 | put_cred(cred); |
812 | ||
813 | return error; | |
814 | } |