1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Implementation of the security services.
4 *
5 * Authors : Stephen Smalley, <stephen.smalley.work@gmail.com>
6 * James Morris <jmorris@redhat.com>
7 *
8 * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
9 *
10 * Support for enhanced MLS infrastructure.
11 * Support for context based audit filters.
12 *
13 * Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
14 *
15 * Added conditional policy language extensions
16 *
17 * Updated: Hewlett-Packard <paul@paul-moore.com>
18 *
19 * Added support for NetLabel
20 * Added support for the policy capability bitmap
21 *
22 * Updated: Chad Sellers <csellers@tresys.com>
23 *
24 * Added validation of kernel classes and permissions
25 *
26 * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
27 *
28 * Added support for bounds domain and audit messaged on masked permissions
29 *
30 * Updated: Guido Trentalancia <guido@trentalancia.com>
31 *
32 * Added support for runtime switching of the policy type
33 *
34 * Copyright (C) 2008, 2009 NEC Corporation
35 * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
36 * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
37 * Copyright (C) 2003 - 2004, 2006 Tresys Technology, LLC
38 * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
39 */
40 #include <linux/kernel.h>
41 #include <linux/slab.h>
42 #include <linux/string.h>
43 #include <linux/spinlock.h>
44 #include <linux/rcupdate.h>
45 #include <linux/errno.h>
46 #include <linux/in.h>
47 #include <linux/sched.h>
48 #include <linux/audit.h>
49 #include <linux/vmalloc.h>
50 #include <linux/lsm_hooks.h>
51 #include <net/netlabel.h>
52
53 #include "flask.h"
54 #include "avc.h"
55 #include "avc_ss.h"
56 #include "security.h"
57 #include "context.h"
58 #include "policydb.h"
59 #include "sidtab.h"
60 #include "services.h"
61 #include "conditional.h"
62 #include "mls.h"
63 #include "objsec.h"
64 #include "netlabel.h"
65 #include "xfrm.h"
66 #include "ebitmap.h"
67 #include "audit.h"
68 #include "policycap_names.h"
69 #include "ima.h"
70
71 struct selinux_policy_convert_data {
72 struct convert_context_args args;
73 struct sidtab_convert_params sidtab_params;
74 };
75
76 /* Forward declaration. */
77 static int context_struct_to_string(struct policydb *policydb,
78 struct context *context,
79 char **scontext,
80 u32 *scontext_len);
81
82 static int sidtab_entry_to_string(struct policydb *policydb,
83 struct sidtab *sidtab,
84 struct sidtab_entry *entry,
85 char **scontext,
86 u32 *scontext_len);
87
88 static void context_struct_compute_av(struct policydb *policydb,
89 struct context *scontext,
90 struct context *tcontext,
91 u16 tclass,
92 struct av_decision *avd,
93 struct extended_perms *xperms);
94
selinux_set_mapping(struct policydb * pol,const struct security_class_mapping * map,struct selinux_map * out_map)95 static int selinux_set_mapping(struct policydb *pol,
96 const struct security_class_mapping *map,
97 struct selinux_map *out_map)
98 {
99 u16 i, j;
100 bool print_unknown_handle = false;
101
102 /* Find number of classes in the input mapping */
103 if (!map)
104 return -EINVAL;
105 i = 0;
106 while (map[i].name)
107 i++;
108
109 /* Allocate space for the class records, plus one for class zero */
110 out_map->mapping = kcalloc(++i, sizeof(*out_map->mapping), GFP_ATOMIC);
111 if (!out_map->mapping)
112 return -ENOMEM;
113
114 /* Store the raw class and permission values */
115 j = 0;
116 while (map[j].name) {
117 const struct security_class_mapping *p_in = map + (j++);
118 struct selinux_mapping *p_out = out_map->mapping + j;
119 u16 k;
120
121 /* An empty class string skips ahead */
122 if (!strcmp(p_in->name, "")) {
123 p_out->num_perms = 0;
124 continue;
125 }
126
127 p_out->value = string_to_security_class(pol, p_in->name);
128 if (!p_out->value) {
129 pr_info("SELinux: Class %s not defined in policy.\n",
130 p_in->name);
131 if (pol->reject_unknown)
132 goto err;
133 p_out->num_perms = 0;
134 print_unknown_handle = true;
135 continue;
136 }
137
138 k = 0;
139 while (p_in->perms[k]) {
140 /* An empty permission string skips ahead */
141 if (!*p_in->perms[k]) {
142 k++;
143 continue;
144 }
145 p_out->perms[k] = string_to_av_perm(pol, p_out->value,
146 p_in->perms[k]);
147 if (!p_out->perms[k]) {
148 pr_info("SELinux: Permission %s in class %s not defined in policy.\n",
149 p_in->perms[k], p_in->name);
150 if (pol->reject_unknown)
151 goto err;
152 print_unknown_handle = true;
153 }
154
155 k++;
156 }
157 p_out->num_perms = k;
158 }
159
160 if (print_unknown_handle)
161 pr_info("SELinux: the above unknown classes and permissions will be %s\n",
162 pol->allow_unknown ? "allowed" : "denied");
163
164 out_map->size = i;
165 return 0;
166 err:
167 kfree(out_map->mapping);
168 out_map->mapping = NULL;
169 return -EINVAL;
170 }
171
172 /*
173 * Get real, policy values from mapped values
174 */
175
unmap_class(struct selinux_map * map,u16 tclass)176 static u16 unmap_class(struct selinux_map *map, u16 tclass)
177 {
178 if (tclass < map->size)
179 return map->mapping[tclass].value;
180
181 return tclass;
182 }
183
184 /*
185 * Get kernel value for class from its policy value
186 */
map_class(struct selinux_map * map,u16 pol_value)187 static u16 map_class(struct selinux_map *map, u16 pol_value)
188 {
189 u16 i;
190
191 for (i = 1; i < map->size; i++) {
192 if (map->mapping[i].value == pol_value)
193 return i;
194 }
195
196 return SECCLASS_NULL;
197 }
198
map_decision(struct selinux_map * map,u16 tclass,struct av_decision * avd,int allow_unknown)199 static void map_decision(struct selinux_map *map,
200 u16 tclass, struct av_decision *avd,
201 int allow_unknown)
202 {
203 if (tclass < map->size) {
204 struct selinux_mapping *mapping = &map->mapping[tclass];
205 unsigned int i, n = mapping->num_perms;
206 u32 result;
207
208 for (i = 0, result = 0; i < n; i++) {
209 if (avd->allowed & mapping->perms[i])
210 result |= (u32)1<<i;
211 if (allow_unknown && !mapping->perms[i])
212 result |= (u32)1<<i;
213 }
214 avd->allowed = result;
215
216 for (i = 0, result = 0; i < n; i++)
217 if (avd->auditallow & mapping->perms[i])
218 result |= (u32)1<<i;
219 avd->auditallow = result;
220
221 for (i = 0, result = 0; i < n; i++) {
222 if (avd->auditdeny & mapping->perms[i])
223 result |= (u32)1<<i;
224 if (!allow_unknown && !mapping->perms[i])
225 result |= (u32)1<<i;
226 }
227 /*
228 * In case the kernel has a bug and requests a permission
229 * between num_perms and the maximum permission number, we
230 * should audit that denial
231 */
232 for (; i < (sizeof(u32)*8); i++)
233 result |= (u32)1<<i;
234 avd->auditdeny = result;
235 }
236 }
237
security_mls_enabled(void)238 int security_mls_enabled(void)
239 {
240 int mls_enabled;
241 struct selinux_policy *policy;
242
243 if (!selinux_initialized())
244 return 0;
245
246 rcu_read_lock();
247 policy = rcu_dereference(selinux_state.policy);
248 mls_enabled = policy->policydb.mls_enabled;
249 rcu_read_unlock();
250 return mls_enabled;
251 }
252
253 /*
254 * Return the boolean value of a constraint expression
255 * when it is applied to the specified source and target
256 * security contexts.
257 *
258 * xcontext is a special beast... It is used by the validatetrans rules
259 * only. For these rules, scontext is the context before the transition,
260 * tcontext is the context after the transition, and xcontext is the context
261 * of the process performing the transition. All other callers of
262 * constraint_expr_eval should pass in NULL for xcontext.
263 */
constraint_expr_eval(struct policydb * policydb,struct context * scontext,struct context * tcontext,struct context * xcontext,struct constraint_expr * cexpr)264 static int constraint_expr_eval(struct policydb *policydb,
265 struct context *scontext,
266 struct context *tcontext,
267 struct context *xcontext,
268 struct constraint_expr *cexpr)
269 {
270 u32 val1, val2;
271 struct context *c;
272 struct role_datum *r1, *r2;
273 struct mls_level *l1, *l2;
274 struct constraint_expr *e;
275 int s[CEXPR_MAXDEPTH];
276 int sp = -1;
277
278 for (e = cexpr; e; e = e->next) {
279 switch (e->expr_type) {
280 case CEXPR_NOT:
281 BUG_ON(sp < 0);
282 s[sp] = !s[sp];
283 break;
284 case CEXPR_AND:
285 BUG_ON(sp < 1);
286 sp--;
287 s[sp] &= s[sp + 1];
288 break;
289 case CEXPR_OR:
290 BUG_ON(sp < 1);
291 sp--;
292 s[sp] |= s[sp + 1];
293 break;
294 case CEXPR_ATTR:
295 if (sp == (CEXPR_MAXDEPTH - 1))
296 return 0;
297 switch (e->attr) {
298 case CEXPR_USER:
299 val1 = scontext->user;
300 val2 = tcontext->user;
301 break;
302 case CEXPR_TYPE:
303 val1 = scontext->type;
304 val2 = tcontext->type;
305 break;
306 case CEXPR_ROLE:
307 val1 = scontext->role;
308 val2 = tcontext->role;
309 r1 = policydb->role_val_to_struct[val1 - 1];
310 r2 = policydb->role_val_to_struct[val2 - 1];
311 switch (e->op) {
312 case CEXPR_DOM:
313 s[++sp] = ebitmap_get_bit(&r1->dominates,
314 val2 - 1);
315 continue;
316 case CEXPR_DOMBY:
317 s[++sp] = ebitmap_get_bit(&r2->dominates,
318 val1 - 1);
319 continue;
320 case CEXPR_INCOMP:
321 s[++sp] = (!ebitmap_get_bit(&r1->dominates,
322 val2 - 1) &&
323 !ebitmap_get_bit(&r2->dominates,
324 val1 - 1));
325 continue;
326 default:
327 break;
328 }
329 break;
330 case CEXPR_L1L2:
331 l1 = &(scontext->range.level[0]);
332 l2 = &(tcontext->range.level[0]);
333 goto mls_ops;
334 case CEXPR_L1H2:
335 l1 = &(scontext->range.level[0]);
336 l2 = &(tcontext->range.level[1]);
337 goto mls_ops;
338 case CEXPR_H1L2:
339 l1 = &(scontext->range.level[1]);
340 l2 = &(tcontext->range.level[0]);
341 goto mls_ops;
342 case CEXPR_H1H2:
343 l1 = &(scontext->range.level[1]);
344 l2 = &(tcontext->range.level[1]);
345 goto mls_ops;
346 case CEXPR_L1H1:
347 l1 = &(scontext->range.level[0]);
348 l2 = &(scontext->range.level[1]);
349 goto mls_ops;
350 case CEXPR_L2H2:
351 l1 = &(tcontext->range.level[0]);
352 l2 = &(tcontext->range.level[1]);
353 goto mls_ops;
354 mls_ops:
355 switch (e->op) {
356 case CEXPR_EQ:
357 s[++sp] = mls_level_eq(l1, l2);
358 continue;
359 case CEXPR_NEQ:
360 s[++sp] = !mls_level_eq(l1, l2);
361 continue;
362 case CEXPR_DOM:
363 s[++sp] = mls_level_dom(l1, l2);
364 continue;
365 case CEXPR_DOMBY:
366 s[++sp] = mls_level_dom(l2, l1);
367 continue;
368 case CEXPR_INCOMP:
369 s[++sp] = mls_level_incomp(l2, l1);
370 continue;
371 default:
372 BUG();
373 return 0;
374 }
375 break;
376 default:
377 BUG();
378 return 0;
379 }
380
381 switch (e->op) {
382 case CEXPR_EQ:
383 s[++sp] = (val1 == val2);
384 break;
385 case CEXPR_NEQ:
386 s[++sp] = (val1 != val2);
387 break;
388 default:
389 BUG();
390 return 0;
391 }
392 break;
393 case CEXPR_NAMES:
394 if (sp == (CEXPR_MAXDEPTH-1))
395 return 0;
396 c = scontext;
397 if (e->attr & CEXPR_TARGET)
398 c = tcontext;
399 else if (e->attr & CEXPR_XTARGET) {
400 c = xcontext;
401 if (!c) {
402 BUG();
403 return 0;
404 }
405 }
406 if (e->attr & CEXPR_USER)
407 val1 = c->user;
408 else if (e->attr & CEXPR_ROLE)
409 val1 = c->role;
410 else if (e->attr & CEXPR_TYPE)
411 val1 = c->type;
412 else {
413 BUG();
414 return 0;
415 }
416
417 switch (e->op) {
418 case CEXPR_EQ:
419 s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
420 break;
421 case CEXPR_NEQ:
422 s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
423 break;
424 default:
425 BUG();
426 return 0;
427 }
428 break;
429 default:
430 BUG();
431 return 0;
432 }
433 }
434
435 BUG_ON(sp != 0);
436 return s[0];
437 }
438
439 /*
440 * security_dump_masked_av - dumps masked permissions during
441 * security_compute_av due to RBAC, MLS/Constraint and Type bounds.
442 */
dump_masked_av_helper(void * k,void * d,void * args)443 static int dump_masked_av_helper(void *k, void *d, void *args)
444 {
445 struct perm_datum *pdatum = d;
446 char **permission_names = args;
447
448 BUG_ON(pdatum->value < 1 || pdatum->value > 32);
449
450 permission_names[pdatum->value - 1] = (char *)k;
451
452 return 0;
453 }
454
security_dump_masked_av(struct policydb * policydb,struct context * scontext,struct context * tcontext,u16 tclass,u32 permissions,const char * reason)455 static void security_dump_masked_av(struct policydb *policydb,
456 struct context *scontext,
457 struct context *tcontext,
458 u16 tclass,
459 u32 permissions,
460 const char *reason)
461 {
462 struct common_datum *common_dat;
463 struct class_datum *tclass_dat;
464 struct audit_buffer *ab;
465 char *tclass_name;
466 char *scontext_name = NULL;
467 char *tcontext_name = NULL;
468 char *permission_names[32];
469 int index;
470 u32 length;
471 bool need_comma = false;
472
473 if (!permissions)
474 return;
475
476 tclass_name = sym_name(policydb, SYM_CLASSES, tclass - 1);
477 tclass_dat = policydb->class_val_to_struct[tclass - 1];
478 common_dat = tclass_dat->comdatum;
479
480 /* init permission_names */
481 if (common_dat &&
482 hashtab_map(&common_dat->permissions.table,
483 dump_masked_av_helper, permission_names) < 0)
484 goto out;
485
486 if (hashtab_map(&tclass_dat->permissions.table,
487 dump_masked_av_helper, permission_names) < 0)
488 goto out;
489
490 /* get scontext/tcontext in text form */
491 if (context_struct_to_string(policydb, scontext,
492 &scontext_name, &length) < 0)
493 goto out;
494
495 if (context_struct_to_string(policydb, tcontext,
496 &tcontext_name, &length) < 0)
497 goto out;
498
499 /* audit a message */
500 ab = audit_log_start(audit_context(),
501 GFP_ATOMIC, AUDIT_SELINUX_ERR);
502 if (!ab)
503 goto out;
504
505 audit_log_format(ab, "op=security_compute_av reason=%s "
506 "scontext=%s tcontext=%s tclass=%s perms=",
507 reason, scontext_name, tcontext_name, tclass_name);
508
509 for (index = 0; index < 32; index++) {
510 u32 mask = (1 << index);
511
512 if ((mask & permissions) == 0)
513 continue;
514
515 audit_log_format(ab, "%s%s",
516 need_comma ? "," : "",
517 permission_names[index]
518 ? permission_names[index] : "????");
519 need_comma = true;
520 }
521 audit_log_end(ab);
522 out:
523 /* release scontext/tcontext */
524 kfree(tcontext_name);
525 kfree(scontext_name);
526 }
527
528 /*
529 * security_boundary_permission - drops violated permissions
530 * on boundary constraint.
531 */
type_attribute_bounds_av(struct policydb * policydb,struct context * scontext,struct context * tcontext,u16 tclass,struct av_decision * avd)532 static void type_attribute_bounds_av(struct policydb *policydb,
533 struct context *scontext,
534 struct context *tcontext,
535 u16 tclass,
536 struct av_decision *avd)
537 {
538 struct context lo_scontext;
539 struct context lo_tcontext, *tcontextp = tcontext;
540 struct av_decision lo_avd;
541 struct type_datum *source;
542 struct type_datum *target;
543 u32 masked = 0;
544
545 source = policydb->type_val_to_struct[scontext->type - 1];
546 BUG_ON(!source);
547
548 if (!source->bounds)
549 return;
550
551 target = policydb->type_val_to_struct[tcontext->type - 1];
552 BUG_ON(!target);
553
554 memset(&lo_avd, 0, sizeof(lo_avd));
555
556 memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
557 lo_scontext.type = source->bounds;
558
559 if (target->bounds) {
560 memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
561 lo_tcontext.type = target->bounds;
562 tcontextp = &lo_tcontext;
563 }
564
565 context_struct_compute_av(policydb, &lo_scontext,
566 tcontextp,
567 tclass,
568 &lo_avd,
569 NULL);
570
571 masked = ~lo_avd.allowed & avd->allowed;
572
573 if (likely(!masked))
574 return; /* no masked permission */
575
576 /* mask violated permissions */
577 avd->allowed &= ~masked;
578
579 /* audit masked permissions */
580 security_dump_masked_av(policydb, scontext, tcontext,
581 tclass, masked, "bounds");
582 }
583
584 /*
585 * flag which drivers have permissions
586 * only looking for ioctl based extended permissions
587 */
services_compute_xperms_drivers(struct extended_perms * xperms,struct avtab_node * node)588 void services_compute_xperms_drivers(
589 struct extended_perms *xperms,
590 struct avtab_node *node)
591 {
592 unsigned int i;
593
594 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
595 /* if one or more driver has all permissions allowed */
596 for (i = 0; i < ARRAY_SIZE(xperms->drivers.p); i++)
597 xperms->drivers.p[i] |= node->datum.u.xperms->perms.p[i];
598 } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
599 /* if allowing permissions within a driver */
600 security_xperm_set(xperms->drivers.p,
601 node->datum.u.xperms->driver);
602 }
603
604 xperms->len = 1;
605 }
606
607 /*
608 * Compute access vectors and extended permissions based on a context
609 * structure pair for the permissions in a particular class.
610 */
context_struct_compute_av(struct policydb * policydb,struct context * scontext,struct context * tcontext,u16 tclass,struct av_decision * avd,struct extended_perms * xperms)611 static void context_struct_compute_av(struct policydb *policydb,
612 struct context *scontext,
613 struct context *tcontext,
614 u16 tclass,
615 struct av_decision *avd,
616 struct extended_perms *xperms)
617 {
618 struct constraint_node *constraint;
619 struct role_allow *ra;
620 struct avtab_key avkey;
621 struct avtab_node *node;
622 struct class_datum *tclass_datum;
623 struct ebitmap *sattr, *tattr;
624 struct ebitmap_node *snode, *tnode;
625 unsigned int i, j;
626
627 avd->allowed = 0;
628 avd->auditallow = 0;
629 avd->auditdeny = 0xffffffff;
630 if (xperms) {
631 memset(&xperms->drivers, 0, sizeof(xperms->drivers));
632 xperms->len = 0;
633 }
634
635 if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
636 if (printk_ratelimit())
637 pr_warn("SELinux: Invalid class %hu\n", tclass);
638 return;
639 }
640
641 tclass_datum = policydb->class_val_to_struct[tclass - 1];
642
643 /*
644 * If a specific type enforcement rule was defined for
645 * this permission check, then use it.
646 */
647 avkey.target_class = tclass;
648 avkey.specified = AVTAB_AV | AVTAB_XPERMS;
649 sattr = &policydb->type_attr_map_array[scontext->type - 1];
650 tattr = &policydb->type_attr_map_array[tcontext->type - 1];
651 ebitmap_for_each_positive_bit(sattr, snode, i) {
652 ebitmap_for_each_positive_bit(tattr, tnode, j) {
653 avkey.source_type = i + 1;
654 avkey.target_type = j + 1;
655 for (node = avtab_search_node(&policydb->te_avtab,
656 &avkey);
657 node;
658 node = avtab_search_node_next(node, avkey.specified)) {
659 if (node->key.specified == AVTAB_ALLOWED)
660 avd->allowed |= node->datum.u.data;
661 else if (node->key.specified == AVTAB_AUDITALLOW)
662 avd->auditallow |= node->datum.u.data;
663 else if (node->key.specified == AVTAB_AUDITDENY)
664 avd->auditdeny &= node->datum.u.data;
665 else if (xperms && (node->key.specified & AVTAB_XPERMS))
666 services_compute_xperms_drivers(xperms, node);
667 }
668
669 /* Check conditional av table for additional permissions */
670 cond_compute_av(&policydb->te_cond_avtab, &avkey,
671 avd, xperms);
672
673 }
674 }
675
676 /*
677 * Remove any permissions prohibited by a constraint (this includes
678 * the MLS policy).
679 */
680 constraint = tclass_datum->constraints;
681 while (constraint) {
682 if ((constraint->permissions & (avd->allowed)) &&
683 !constraint_expr_eval(policydb, scontext, tcontext, NULL,
684 constraint->expr)) {
685 avd->allowed &= ~(constraint->permissions);
686 }
687 constraint = constraint->next;
688 }
689
690 /*
691 * If checking process transition permission and the
692 * role is changing, then check the (current_role, new_role)
693 * pair.
694 */
695 if (tclass == policydb->process_class &&
696 (avd->allowed & policydb->process_trans_perms) &&
697 scontext->role != tcontext->role) {
698 for (ra = policydb->role_allow; ra; ra = ra->next) {
699 if (scontext->role == ra->role &&
700 tcontext->role == ra->new_role)
701 break;
702 }
703 if (!ra)
704 avd->allowed &= ~policydb->process_trans_perms;
705 }
706
707 /*
708 * If the given source and target types have boundary
709 * constraint, lazy checks have to mask any violated
710 * permission and notice it to userspace via audit.
711 */
712 type_attribute_bounds_av(policydb, scontext, tcontext,
713 tclass, avd);
714 }
715
security_validtrans_handle_fail(struct selinux_policy * policy,struct sidtab_entry * oentry,struct sidtab_entry * nentry,struct sidtab_entry * tentry,u16 tclass)716 static int security_validtrans_handle_fail(struct selinux_policy *policy,
717 struct sidtab_entry *oentry,
718 struct sidtab_entry *nentry,
719 struct sidtab_entry *tentry,
720 u16 tclass)
721 {
722 struct policydb *p = &policy->policydb;
723 struct sidtab *sidtab = policy->sidtab;
724 char *o = NULL, *n = NULL, *t = NULL;
725 u32 olen, nlen, tlen;
726
727 if (sidtab_entry_to_string(p, sidtab, oentry, &o, &olen))
728 goto out;
729 if (sidtab_entry_to_string(p, sidtab, nentry, &n, &nlen))
730 goto out;
731 if (sidtab_entry_to_string(p, sidtab, tentry, &t, &tlen))
732 goto out;
733 audit_log(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR,
734 "op=security_validate_transition seresult=denied"
735 " oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
736 o, n, t, sym_name(p, SYM_CLASSES, tclass-1));
737 out:
738 kfree(o);
739 kfree(n);
740 kfree(t);
741
742 if (!enforcing_enabled())
743 return 0;
744 return -EPERM;
745 }
746
security_compute_validatetrans(u32 oldsid,u32 newsid,u32 tasksid,u16 orig_tclass,bool user)747 static int security_compute_validatetrans(u32 oldsid, u32 newsid, u32 tasksid,
748 u16 orig_tclass, bool user)
749 {
750 struct selinux_policy *policy;
751 struct policydb *policydb;
752 struct sidtab *sidtab;
753 struct sidtab_entry *oentry;
754 struct sidtab_entry *nentry;
755 struct sidtab_entry *tentry;
756 struct class_datum *tclass_datum;
757 struct constraint_node *constraint;
758 u16 tclass;
759 int rc = 0;
760
761
762 if (!selinux_initialized())
763 return 0;
764
765 rcu_read_lock();
766
767 policy = rcu_dereference(selinux_state.policy);
768 policydb = &policy->policydb;
769 sidtab = policy->sidtab;
770
771 if (!user)
772 tclass = unmap_class(&policy->map, orig_tclass);
773 else
774 tclass = orig_tclass;
775
776 if (!tclass || tclass > policydb->p_classes.nprim) {
777 rc = -EINVAL;
778 goto out;
779 }
780 tclass_datum = policydb->class_val_to_struct[tclass - 1];
781
782 oentry = sidtab_search_entry(sidtab, oldsid);
783 if (!oentry) {
784 pr_err("SELinux: %s: unrecognized SID %d\n",
785 __func__, oldsid);
786 rc = -EINVAL;
787 goto out;
788 }
789
790 nentry = sidtab_search_entry(sidtab, newsid);
791 if (!nentry) {
792 pr_err("SELinux: %s: unrecognized SID %d\n",
793 __func__, newsid);
794 rc = -EINVAL;
795 goto out;
796 }
797
798 tentry = sidtab_search_entry(sidtab, tasksid);
799 if (!tentry) {
800 pr_err("SELinux: %s: unrecognized SID %d\n",
801 __func__, tasksid);
802 rc = -EINVAL;
803 goto out;
804 }
805
806 constraint = tclass_datum->validatetrans;
807 while (constraint) {
808 if (!constraint_expr_eval(policydb, &oentry->context,
809 &nentry->context, &tentry->context,
810 constraint->expr)) {
811 if (user)
812 rc = -EPERM;
813 else
814 rc = security_validtrans_handle_fail(policy,
815 oentry,
816 nentry,
817 tentry,
818 tclass);
819 goto out;
820 }
821 constraint = constraint->next;
822 }
823
824 out:
825 rcu_read_unlock();
826 return rc;
827 }
828
security_validate_transition_user(u32 oldsid,u32 newsid,u32 tasksid,u16 tclass)829 int security_validate_transition_user(u32 oldsid, u32 newsid, u32 tasksid,
830 u16 tclass)
831 {
832 return security_compute_validatetrans(oldsid, newsid, tasksid,
833 tclass, true);
834 }
835
security_validate_transition(u32 oldsid,u32 newsid,u32 tasksid,u16 orig_tclass)836 int security_validate_transition(u32 oldsid, u32 newsid, u32 tasksid,
837 u16 orig_tclass)
838 {
839 return security_compute_validatetrans(oldsid, newsid, tasksid,
840 orig_tclass, false);
841 }
842
843 /*
844 * security_bounded_transition - check whether the given
845 * transition is directed to bounded, or not.
846 * It returns 0, if @newsid is bounded by @oldsid.
847 * Otherwise, it returns error code.
848 *
849 * @oldsid : current security identifier
850 * @newsid : destinated security identifier
851 */
security_bounded_transition(u32 old_sid,u32 new_sid)852 int security_bounded_transition(u32 old_sid, u32 new_sid)
853 {
854 struct selinux_policy *policy;
855 struct policydb *policydb;
856 struct sidtab *sidtab;
857 struct sidtab_entry *old_entry, *new_entry;
858 struct type_datum *type;
859 u32 index;
860 int rc;
861
862 if (!selinux_initialized())
863 return 0;
864
865 rcu_read_lock();
866 policy = rcu_dereference(selinux_state.policy);
867 policydb = &policy->policydb;
868 sidtab = policy->sidtab;
869
870 rc = -EINVAL;
871 old_entry = sidtab_search_entry(sidtab, old_sid);
872 if (!old_entry) {
873 pr_err("SELinux: %s: unrecognized SID %u\n",
874 __func__, old_sid);
875 goto out;
876 }
877
878 rc = -EINVAL;
879 new_entry = sidtab_search_entry(sidtab, new_sid);
880 if (!new_entry) {
881 pr_err("SELinux: %s: unrecognized SID %u\n",
882 __func__, new_sid);
883 goto out;
884 }
885
886 rc = 0;
887 /* type/domain unchanged */
888 if (old_entry->context.type == new_entry->context.type)
889 goto out;
890
891 index = new_entry->context.type;
892 while (true) {
893 type = policydb->type_val_to_struct[index - 1];
894 BUG_ON(!type);
895
896 /* not bounded anymore */
897 rc = -EPERM;
898 if (!type->bounds)
899 break;
900
901 /* @newsid is bounded by @oldsid */
902 rc = 0;
903 if (type->bounds == old_entry->context.type)
904 break;
905
906 index = type->bounds;
907 }
908
909 if (rc) {
910 char *old_name = NULL;
911 char *new_name = NULL;
912 u32 length;
913
914 if (!sidtab_entry_to_string(policydb, sidtab, old_entry,
915 &old_name, &length) &&
916 !sidtab_entry_to_string(policydb, sidtab, new_entry,
917 &new_name, &length)) {
918 audit_log(audit_context(),
919 GFP_ATOMIC, AUDIT_SELINUX_ERR,
920 "op=security_bounded_transition "
921 "seresult=denied "
922 "oldcontext=%s newcontext=%s",
923 old_name, new_name);
924 }
925 kfree(new_name);
926 kfree(old_name);
927 }
928 out:
929 rcu_read_unlock();
930
931 return rc;
932 }
933
avd_init(struct selinux_policy * policy,struct av_decision * avd)934 static void avd_init(struct selinux_policy *policy, struct av_decision *avd)
935 {
936 avd->allowed = 0;
937 avd->auditallow = 0;
938 avd->auditdeny = 0xffffffff;
939 if (policy)
940 avd->seqno = policy->latest_granting;
941 else
942 avd->seqno = 0;
943 avd->flags = 0;
944 }
945
services_compute_xperms_decision(struct extended_perms_decision * xpermd,struct avtab_node * node)946 void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
947 struct avtab_node *node)
948 {
949 unsigned int i;
950
951 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
952 if (xpermd->driver != node->datum.u.xperms->driver)
953 return;
954 } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
955 if (!security_xperm_test(node->datum.u.xperms->perms.p,
956 xpermd->driver))
957 return;
958 } else {
959 BUG();
960 }
961
962 if (node->key.specified == AVTAB_XPERMS_ALLOWED) {
963 xpermd->used |= XPERMS_ALLOWED;
964 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
965 memset(xpermd->allowed->p, 0xff,
966 sizeof(xpermd->allowed->p));
967 }
968 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
969 for (i = 0; i < ARRAY_SIZE(xpermd->allowed->p); i++)
970 xpermd->allowed->p[i] |=
971 node->datum.u.xperms->perms.p[i];
972 }
973 } else if (node->key.specified == AVTAB_XPERMS_AUDITALLOW) {
974 xpermd->used |= XPERMS_AUDITALLOW;
975 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
976 memset(xpermd->auditallow->p, 0xff,
977 sizeof(xpermd->auditallow->p));
978 }
979 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
980 for (i = 0; i < ARRAY_SIZE(xpermd->auditallow->p); i++)
981 xpermd->auditallow->p[i] |=
982 node->datum.u.xperms->perms.p[i];
983 }
984 } else if (node->key.specified == AVTAB_XPERMS_DONTAUDIT) {
985 xpermd->used |= XPERMS_DONTAUDIT;
986 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
987 memset(xpermd->dontaudit->p, 0xff,
988 sizeof(xpermd->dontaudit->p));
989 }
990 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
991 for (i = 0; i < ARRAY_SIZE(xpermd->dontaudit->p); i++)
992 xpermd->dontaudit->p[i] |=
993 node->datum.u.xperms->perms.p[i];
994 }
995 } else {
996 BUG();
997 }
998 }
999
security_compute_xperms_decision(u32 ssid,u32 tsid,u16 orig_tclass,u8 driver,struct extended_perms_decision * xpermd)1000 void security_compute_xperms_decision(u32 ssid,
1001 u32 tsid,
1002 u16 orig_tclass,
1003 u8 driver,
1004 struct extended_perms_decision *xpermd)
1005 {
1006 struct selinux_policy *policy;
1007 struct policydb *policydb;
1008 struct sidtab *sidtab;
1009 u16 tclass;
1010 struct context *scontext, *tcontext;
1011 struct avtab_key avkey;
1012 struct avtab_node *node;
1013 struct ebitmap *sattr, *tattr;
1014 struct ebitmap_node *snode, *tnode;
1015 unsigned int i, j;
1016
1017 xpermd->driver = driver;
1018 xpermd->used = 0;
1019 memset(xpermd->allowed->p, 0, sizeof(xpermd->allowed->p));
1020 memset(xpermd->auditallow->p, 0, sizeof(xpermd->auditallow->p));
1021 memset(xpermd->dontaudit->p, 0, sizeof(xpermd->dontaudit->p));
1022
1023 rcu_read_lock();
1024 if (!selinux_initialized())
1025 goto allow;
1026
1027 policy = rcu_dereference(selinux_state.policy);
1028 policydb = &policy->policydb;
1029 sidtab = policy->sidtab;
1030
1031 scontext = sidtab_search(sidtab, ssid);
1032 if (!scontext) {
1033 pr_err("SELinux: %s: unrecognized SID %d\n",
1034 __func__, ssid);
1035 goto out;
1036 }
1037
1038 tcontext = sidtab_search(sidtab, tsid);
1039 if (!tcontext) {
1040 pr_err("SELinux: %s: unrecognized SID %d\n",
1041 __func__, tsid);
1042 goto out;
1043 }
1044
1045 tclass = unmap_class(&policy->map, orig_tclass);
1046 if (unlikely(orig_tclass && !tclass)) {
1047 if (policydb->allow_unknown)
1048 goto allow;
1049 goto out;
1050 }
1051
1052
1053 if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
1054 pr_warn_ratelimited("SELinux: Invalid class %hu\n", tclass);
1055 goto out;
1056 }
1057
1058 avkey.target_class = tclass;
1059 avkey.specified = AVTAB_XPERMS;
1060 sattr = &policydb->type_attr_map_array[scontext->type - 1];
1061 tattr = &policydb->type_attr_map_array[tcontext->type - 1];
1062 ebitmap_for_each_positive_bit(sattr, snode, i) {
1063 ebitmap_for_each_positive_bit(tattr, tnode, j) {
1064 avkey.source_type = i + 1;
1065 avkey.target_type = j + 1;
1066 for (node = avtab_search_node(&policydb->te_avtab,
1067 &avkey);
1068 node;
1069 node = avtab_search_node_next(node, avkey.specified))
1070 services_compute_xperms_decision(xpermd, node);
1071
1072 cond_compute_xperms(&policydb->te_cond_avtab,
1073 &avkey, xpermd);
1074 }
1075 }
1076 out:
1077 rcu_read_unlock();
1078 return;
1079 allow:
1080 memset(xpermd->allowed->p, 0xff, sizeof(xpermd->allowed->p));
1081 goto out;
1082 }
1083
1084 /**
1085 * security_compute_av - Compute access vector decisions.
1086 * @ssid: source security identifier
1087 * @tsid: target security identifier
1088 * @orig_tclass: target security class
1089 * @avd: access vector decisions
1090 * @xperms: extended permissions
1091 *
1092 * Compute a set of access vector decisions based on the
1093 * SID pair (@ssid, @tsid) for the permissions in @tclass.
1094 */
security_compute_av(u32 ssid,u32 tsid,u16 orig_tclass,struct av_decision * avd,struct extended_perms * xperms)1095 void security_compute_av(u32 ssid,
1096 u32 tsid,
1097 u16 orig_tclass,
1098 struct av_decision *avd,
1099 struct extended_perms *xperms)
1100 {
1101 struct selinux_policy *policy;
1102 struct policydb *policydb;
1103 struct sidtab *sidtab;
1104 u16 tclass;
1105 struct context *scontext = NULL, *tcontext = NULL;
1106
1107 rcu_read_lock();
1108 policy = rcu_dereference(selinux_state.policy);
1109 avd_init(policy, avd);
1110 xperms->len = 0;
1111 if (!selinux_initialized())
1112 goto allow;
1113
1114 policydb = &policy->policydb;
1115 sidtab = policy->sidtab;
1116
1117 scontext = sidtab_search(sidtab, ssid);
1118 if (!scontext) {
1119 pr_err("SELinux: %s: unrecognized SID %d\n",
1120 __func__, ssid);
1121 goto out;
1122 }
1123
1124 /* permissive domain? */
1125 if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
1126 avd->flags |= AVD_FLAGS_PERMISSIVE;
1127
1128 tcontext = sidtab_search(sidtab, tsid);
1129 if (!tcontext) {
1130 pr_err("SELinux: %s: unrecognized SID %d\n",
1131 __func__, tsid);
1132 goto out;
1133 }
1134
1135 tclass = unmap_class(&policy->map, orig_tclass);
1136 if (unlikely(orig_tclass && !tclass)) {
1137 if (policydb->allow_unknown)
1138 goto allow;
1139 goto out;
1140 }
1141 context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
1142 xperms);
1143 map_decision(&policy->map, orig_tclass, avd,
1144 policydb->allow_unknown);
1145 out:
1146 rcu_read_unlock();
1147 return;
1148 allow:
1149 avd->allowed = 0xffffffff;
1150 goto out;
1151 }
1152
security_compute_av_user(u32 ssid,u32 tsid,u16 tclass,struct av_decision * avd)1153 void security_compute_av_user(u32 ssid,
1154 u32 tsid,
1155 u16 tclass,
1156 struct av_decision *avd)
1157 {
1158 struct selinux_policy *policy;
1159 struct policydb *policydb;
1160 struct sidtab *sidtab;
1161 struct context *scontext = NULL, *tcontext = NULL;
1162
1163 rcu_read_lock();
1164 policy = rcu_dereference(selinux_state.policy);
1165 avd_init(policy, avd);
1166 if (!selinux_initialized())
1167 goto allow;
1168
1169 policydb = &policy->policydb;
1170 sidtab = policy->sidtab;
1171
1172 scontext = sidtab_search(sidtab, ssid);
1173 if (!scontext) {
1174 pr_err("SELinux: %s: unrecognized SID %d\n",
1175 __func__, ssid);
1176 goto out;
1177 }
1178
1179 /* permissive domain? */
1180 if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
1181 avd->flags |= AVD_FLAGS_PERMISSIVE;
1182
1183 tcontext = sidtab_search(sidtab, tsid);
1184 if (!tcontext) {
1185 pr_err("SELinux: %s: unrecognized SID %d\n",
1186 __func__, tsid);
1187 goto out;
1188 }
1189
1190 if (unlikely(!tclass)) {
1191 if (policydb->allow_unknown)
1192 goto allow;
1193 goto out;
1194 }
1195
1196 context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
1197 NULL);
1198 out:
1199 rcu_read_unlock();
1200 return;
1201 allow:
1202 avd->allowed = 0xffffffff;
1203 goto out;
1204 }
1205
1206 /*
1207 * Write the security context string representation of
1208 * the context structure `context' into a dynamically
1209 * allocated string of the correct size. Set `*scontext'
1210 * to point to this string and set `*scontext_len' to
1211 * the length of the string.
1212 */
context_struct_to_string(struct policydb * p,struct context * context,char ** scontext,u32 * scontext_len)1213 static int context_struct_to_string(struct policydb *p,
1214 struct context *context,
1215 char **scontext, u32 *scontext_len)
1216 {
1217 char *scontextp;
1218
1219 if (scontext)
1220 *scontext = NULL;
1221 *scontext_len = 0;
1222
1223 if (context->len) {
1224 *scontext_len = context->len;
1225 if (scontext) {
1226 *scontext = kstrdup(context->str, GFP_ATOMIC);
1227 if (!(*scontext))
1228 return -ENOMEM;
1229 }
1230 return 0;
1231 }
1232
1233 /* Compute the size of the context. */
1234 *scontext_len += strlen(sym_name(p, SYM_USERS, context->user - 1)) + 1;
1235 *scontext_len += strlen(sym_name(p, SYM_ROLES, context->role - 1)) + 1;
1236 *scontext_len += strlen(sym_name(p, SYM_TYPES, context->type - 1)) + 1;
1237 *scontext_len += mls_compute_context_len(p, context);
1238
1239 if (!scontext)
1240 return 0;
1241
1242 /* Allocate space for the context; caller must free this space. */
1243 scontextp = kmalloc(*scontext_len, GFP_ATOMIC);
1244 if (!scontextp)
1245 return -ENOMEM;
1246 *scontext = scontextp;
1247
1248 /*
1249 * Copy the user name, role name and type name into the context.
1250 */
1251 scontextp += sprintf(scontextp, "%s:%s:%s",
1252 sym_name(p, SYM_USERS, context->user - 1),
1253 sym_name(p, SYM_ROLES, context->role - 1),
1254 sym_name(p, SYM_TYPES, context->type - 1));
1255
1256 mls_sid_to_context(p, context, &scontextp);
1257
1258 *scontextp = 0;
1259
1260 return 0;
1261 }
1262
sidtab_entry_to_string(struct policydb * p,struct sidtab * sidtab,struct sidtab_entry * entry,char ** scontext,u32 * scontext_len)1263 static int sidtab_entry_to_string(struct policydb *p,
1264 struct sidtab *sidtab,
1265 struct sidtab_entry *entry,
1266 char **scontext, u32 *scontext_len)
1267 {
1268 int rc = sidtab_sid2str_get(sidtab, entry, scontext, scontext_len);
1269
1270 if (rc != -ENOENT)
1271 return rc;
1272
1273 rc = context_struct_to_string(p, &entry->context, scontext,
1274 scontext_len);
1275 if (!rc && scontext)
1276 sidtab_sid2str_put(sidtab, entry, *scontext, *scontext_len);
1277 return rc;
1278 }
1279
1280 #include "initial_sid_to_string.h"
1281
security_sidtab_hash_stats(char * page)1282 int security_sidtab_hash_stats(char *page)
1283 {
1284 struct selinux_policy *policy;
1285 int rc;
1286
1287 if (!selinux_initialized()) {
1288 pr_err("SELinux: %s: called before initial load_policy\n",
1289 __func__);
1290 return -EINVAL;
1291 }
1292
1293 rcu_read_lock();
1294 policy = rcu_dereference(selinux_state.policy);
1295 rc = sidtab_hash_stats(policy->sidtab, page);
1296 rcu_read_unlock();
1297
1298 return rc;
1299 }
1300
security_get_initial_sid_context(u32 sid)1301 const char *security_get_initial_sid_context(u32 sid)
1302 {
1303 if (unlikely(sid > SECINITSID_NUM))
1304 return NULL;
1305 return initial_sid_to_string[sid];
1306 }
1307
security_sid_to_context_core(u32 sid,char ** scontext,u32 * scontext_len,int force,int only_invalid)1308 static int security_sid_to_context_core(u32 sid, char **scontext,
1309 u32 *scontext_len, int force,
1310 int only_invalid)
1311 {
1312 struct selinux_policy *policy;
1313 struct policydb *policydb;
1314 struct sidtab *sidtab;
1315 struct sidtab_entry *entry;
1316 int rc = 0;
1317
1318 if (scontext)
1319 *scontext = NULL;
1320 *scontext_len = 0;
1321
1322 if (!selinux_initialized()) {
1323 if (sid <= SECINITSID_NUM) {
1324 char *scontextp;
1325 const char *s;
1326
1327 /*
1328 * Before the policy is loaded, translate
1329 * SECINITSID_INIT to "kernel", because systemd and
1330 * libselinux < 2.6 take a getcon_raw() result that is
1331 * both non-null and not "kernel" to mean that a policy
1332 * is already loaded.
1333 */
1334 if (sid == SECINITSID_INIT)
1335 sid = SECINITSID_KERNEL;
1336
1337 s = initial_sid_to_string[sid];
1338 if (!s)
1339 return -EINVAL;
1340 *scontext_len = strlen(s) + 1;
1341 if (!scontext)
1342 return 0;
1343 scontextp = kmemdup(s, *scontext_len, GFP_ATOMIC);
1344 if (!scontextp)
1345 return -ENOMEM;
1346 *scontext = scontextp;
1347 return 0;
1348 }
1349 pr_err("SELinux: %s: called before initial "
1350 "load_policy on unknown SID %d\n", __func__, sid);
1351 return -EINVAL;
1352 }
1353 rcu_read_lock();
1354 policy = rcu_dereference(selinux_state.policy);
1355 policydb = &policy->policydb;
1356 sidtab = policy->sidtab;
1357
1358 if (force)
1359 entry = sidtab_search_entry_force(sidtab, sid);
1360 else
1361 entry = sidtab_search_entry(sidtab, sid);
1362 if (!entry) {
1363 pr_err("SELinux: %s: unrecognized SID %d\n",
1364 __func__, sid);
1365 rc = -EINVAL;
1366 goto out_unlock;
1367 }
1368 if (only_invalid && !entry->context.len)
1369 goto out_unlock;
1370
1371 rc = sidtab_entry_to_string(policydb, sidtab, entry, scontext,
1372 scontext_len);
1373
1374 out_unlock:
1375 rcu_read_unlock();
1376 return rc;
1377
1378 }
1379
1380 /**
1381 * security_sid_to_context - Obtain a context for a given SID.
1382 * @sid: security identifier, SID
1383 * @scontext: security context
1384 * @scontext_len: length in bytes
1385 *
1386 * Write the string representation of the context associated with @sid
1387 * into a dynamically allocated string of the correct size. Set @scontext
1388 * to point to this string and set @scontext_len to the length of the string.
1389 */
security_sid_to_context(u32 sid,char ** scontext,u32 * scontext_len)1390 int security_sid_to_context(u32 sid, char **scontext, u32 *scontext_len)
1391 {
1392 return security_sid_to_context_core(sid, scontext,
1393 scontext_len, 0, 0);
1394 }
1395
security_sid_to_context_force(u32 sid,char ** scontext,u32 * scontext_len)1396 int security_sid_to_context_force(u32 sid,
1397 char **scontext, u32 *scontext_len)
1398 {
1399 return security_sid_to_context_core(sid, scontext,
1400 scontext_len, 1, 0);
1401 }
1402
1403 /**
1404 * security_sid_to_context_inval - Obtain a context for a given SID if it
1405 * is invalid.
1406 * @sid: security identifier, SID
1407 * @scontext: security context
1408 * @scontext_len: length in bytes
1409 *
1410 * Write the string representation of the context associated with @sid
1411 * into a dynamically allocated string of the correct size, but only if the
1412 * context is invalid in the current policy. Set @scontext to point to
1413 * this string (or NULL if the context is valid) and set @scontext_len to
1414 * the length of the string (or 0 if the context is valid).
1415 */
security_sid_to_context_inval(u32 sid,char ** scontext,u32 * scontext_len)1416 int security_sid_to_context_inval(u32 sid,
1417 char **scontext, u32 *scontext_len)
1418 {
1419 return security_sid_to_context_core(sid, scontext,
1420 scontext_len, 1, 1);
1421 }
1422
1423 /*
1424 * Caveat: Mutates scontext.
1425 */
string_to_context_struct(struct policydb * pol,struct sidtab * sidtabp,char * scontext,struct context * ctx,u32 def_sid)1426 static int string_to_context_struct(struct policydb *pol,
1427 struct sidtab *sidtabp,
1428 char *scontext,
1429 struct context *ctx,
1430 u32 def_sid)
1431 {
1432 struct role_datum *role;
1433 struct type_datum *typdatum;
1434 struct user_datum *usrdatum;
1435 char *scontextp, *p, oldc;
1436 int rc = 0;
1437
1438 context_init(ctx);
1439
1440 /* Parse the security context. */
1441
1442 rc = -EINVAL;
1443 scontextp = scontext;
1444
1445 /* Extract the user. */
1446 p = scontextp;
1447 while (*p && *p != ':')
1448 p++;
1449
1450 if (*p == 0)
1451 goto out;
1452
1453 *p++ = 0;
1454
1455 usrdatum = symtab_search(&pol->p_users, scontextp);
1456 if (!usrdatum)
1457 goto out;
1458
1459 ctx->user = usrdatum->value;
1460
1461 /* Extract role. */
1462 scontextp = p;
1463 while (*p && *p != ':')
1464 p++;
1465
1466 if (*p == 0)
1467 goto out;
1468
1469 *p++ = 0;
1470
1471 role = symtab_search(&pol->p_roles, scontextp);
1472 if (!role)
1473 goto out;
1474 ctx->role = role->value;
1475
1476 /* Extract type. */
1477 scontextp = p;
1478 while (*p && *p != ':')
1479 p++;
1480 oldc = *p;
1481 *p++ = 0;
1482
1483 typdatum = symtab_search(&pol->p_types, scontextp);
1484 if (!typdatum || typdatum->attribute)
1485 goto out;
1486
1487 ctx->type = typdatum->value;
1488
1489 rc = mls_context_to_sid(pol, oldc, p, ctx, sidtabp, def_sid);
1490 if (rc)
1491 goto out;
1492
1493 /* Check the validity of the new context. */
1494 rc = -EINVAL;
1495 if (!policydb_context_isvalid(pol, ctx))
1496 goto out;
1497 rc = 0;
1498 out:
1499 if (rc)
1500 context_destroy(ctx);
1501 return rc;
1502 }
1503
security_context_to_sid_core(const char * scontext,u32 scontext_len,u32 * sid,u32 def_sid,gfp_t gfp_flags,int force)1504 static int security_context_to_sid_core(const char *scontext, u32 scontext_len,
1505 u32 *sid, u32 def_sid, gfp_t gfp_flags,
1506 int force)
1507 {
1508 struct selinux_policy *policy;
1509 struct policydb *policydb;
1510 struct sidtab *sidtab;
1511 char *scontext2, *str = NULL;
1512 struct context context;
1513 int rc = 0;
1514
1515 /* An empty security context is never valid. */
1516 if (!scontext_len)
1517 return -EINVAL;
1518
1519 /* Copy the string to allow changes and ensure a NUL terminator */
1520 scontext2 = kmemdup_nul(scontext, scontext_len, gfp_flags);
1521 if (!scontext2)
1522 return -ENOMEM;
1523
1524 if (!selinux_initialized()) {
1525 u32 i;
1526
1527 for (i = 1; i < SECINITSID_NUM; i++) {
1528 const char *s = initial_sid_to_string[i];
1529
1530 if (s && !strcmp(s, scontext2)) {
1531 *sid = i;
1532 goto out;
1533 }
1534 }
1535 *sid = SECINITSID_KERNEL;
1536 goto out;
1537 }
1538 *sid = SECSID_NULL;
1539
1540 if (force) {
1541 /* Save another copy for storing in uninterpreted form */
1542 rc = -ENOMEM;
1543 str = kstrdup(scontext2, gfp_flags);
1544 if (!str)
1545 goto out;
1546 }
1547 retry:
1548 rcu_read_lock();
1549 policy = rcu_dereference(selinux_state.policy);
1550 policydb = &policy->policydb;
1551 sidtab = policy->sidtab;
1552 rc = string_to_context_struct(policydb, sidtab, scontext2,
1553 &context, def_sid);
1554 if (rc == -EINVAL && force) {
1555 context.str = str;
1556 context.len = strlen(str) + 1;
1557 str = NULL;
1558 } else if (rc)
1559 goto out_unlock;
1560 rc = sidtab_context_to_sid(sidtab, &context, sid);
1561 if (rc == -ESTALE) {
1562 rcu_read_unlock();
1563 if (context.str) {
1564 str = context.str;
1565 context.str = NULL;
1566 }
1567 context_destroy(&context);
1568 goto retry;
1569 }
1570 context_destroy(&context);
1571 out_unlock:
1572 rcu_read_unlock();
1573 out:
1574 kfree(scontext2);
1575 kfree(str);
1576 return rc;
1577 }
1578
1579 /**
1580 * security_context_to_sid - Obtain a SID for a given security context.
1581 * @scontext: security context
1582 * @scontext_len: length in bytes
1583 * @sid: security identifier, SID
1584 * @gfp: context for the allocation
1585 *
1586 * Obtains a SID associated with the security context that
1587 * has the string representation specified by @scontext.
1588 * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1589 * memory is available, or 0 on success.
1590 */
security_context_to_sid(const char * scontext,u32 scontext_len,u32 * sid,gfp_t gfp)1591 int security_context_to_sid(const char *scontext, u32 scontext_len, u32 *sid,
1592 gfp_t gfp)
1593 {
1594 return security_context_to_sid_core(scontext, scontext_len,
1595 sid, SECSID_NULL, gfp, 0);
1596 }
1597
security_context_str_to_sid(const char * scontext,u32 * sid,gfp_t gfp)1598 int security_context_str_to_sid(const char *scontext, u32 *sid, gfp_t gfp)
1599 {
1600 return security_context_to_sid(scontext, strlen(scontext),
1601 sid, gfp);
1602 }
1603
1604 /**
1605 * security_context_to_sid_default - Obtain a SID for a given security context,
1606 * falling back to specified default if needed.
1607 *
1608 * @scontext: security context
1609 * @scontext_len: length in bytes
1610 * @sid: security identifier, SID
1611 * @def_sid: default SID to assign on error
1612 * @gfp_flags: the allocator get-free-page (GFP) flags
1613 *
1614 * Obtains a SID associated with the security context that
1615 * has the string representation specified by @scontext.
1616 * The default SID is passed to the MLS layer to be used to allow
1617 * kernel labeling of the MLS field if the MLS field is not present
1618 * (for upgrading to MLS without full relabel).
1619 * Implicitly forces adding of the context even if it cannot be mapped yet.
1620 * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1621 * memory is available, or 0 on success.
1622 */
security_context_to_sid_default(const char * scontext,u32 scontext_len,u32 * sid,u32 def_sid,gfp_t gfp_flags)1623 int security_context_to_sid_default(const char *scontext, u32 scontext_len,
1624 u32 *sid, u32 def_sid, gfp_t gfp_flags)
1625 {
1626 return security_context_to_sid_core(scontext, scontext_len,
1627 sid, def_sid, gfp_flags, 1);
1628 }
1629
security_context_to_sid_force(const char * scontext,u32 scontext_len,u32 * sid)1630 int security_context_to_sid_force(const char *scontext, u32 scontext_len,
1631 u32 *sid)
1632 {
1633 return security_context_to_sid_core(scontext, scontext_len,
1634 sid, SECSID_NULL, GFP_KERNEL, 1);
1635 }
1636
compute_sid_handle_invalid_context(struct selinux_policy * policy,struct sidtab_entry * sentry,struct sidtab_entry * tentry,u16 tclass,struct context * newcontext)1637 static int compute_sid_handle_invalid_context(
1638 struct selinux_policy *policy,
1639 struct sidtab_entry *sentry,
1640 struct sidtab_entry *tentry,
1641 u16 tclass,
1642 struct context *newcontext)
1643 {
1644 struct policydb *policydb = &policy->policydb;
1645 struct sidtab *sidtab = policy->sidtab;
1646 char *s = NULL, *t = NULL, *n = NULL;
1647 u32 slen, tlen, nlen;
1648 struct audit_buffer *ab;
1649
1650 if (sidtab_entry_to_string(policydb, sidtab, sentry, &s, &slen))
1651 goto out;
1652 if (sidtab_entry_to_string(policydb, sidtab, tentry, &t, &tlen))
1653 goto out;
1654 if (context_struct_to_string(policydb, newcontext, &n, &nlen))
1655 goto out;
1656 ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR);
1657 if (!ab)
1658 goto out;
1659 audit_log_format(ab,
1660 "op=security_compute_sid invalid_context=");
1661 /* no need to record the NUL with untrusted strings */
1662 audit_log_n_untrustedstring(ab, n, nlen - 1);
1663 audit_log_format(ab, " scontext=%s tcontext=%s tclass=%s",
1664 s, t, sym_name(policydb, SYM_CLASSES, tclass-1));
1665 audit_log_end(ab);
1666 out:
1667 kfree(s);
1668 kfree(t);
1669 kfree(n);
1670 if (!enforcing_enabled())
1671 return 0;
1672 return -EACCES;
1673 }
1674
filename_compute_type(struct policydb * policydb,struct context * newcontext,u32 stype,u32 ttype,u16 tclass,const char * objname)1675 static void filename_compute_type(struct policydb *policydb,
1676 struct context *newcontext,
1677 u32 stype, u32 ttype, u16 tclass,
1678 const char *objname)
1679 {
1680 struct filename_trans_key ft;
1681 struct filename_trans_datum *datum;
1682
1683 /*
1684 * Most filename trans rules are going to live in specific directories
1685 * like /dev or /var/run. This bitmap will quickly skip rule searches
1686 * if the ttype does not contain any rules.
1687 */
1688 if (!ebitmap_get_bit(&policydb->filename_trans_ttypes, ttype))
1689 return;
1690
1691 ft.ttype = ttype;
1692 ft.tclass = tclass;
1693 ft.name = objname;
1694
1695 datum = policydb_filenametr_search(policydb, &ft);
1696 while (datum) {
1697 if (ebitmap_get_bit(&datum->stypes, stype - 1)) {
1698 newcontext->type = datum->otype;
1699 return;
1700 }
1701 datum = datum->next;
1702 }
1703 }
1704
security_compute_sid(u32 ssid,u32 tsid,u16 orig_tclass,u16 specified,const char * objname,u32 * out_sid,bool kern)1705 static int security_compute_sid(u32 ssid,
1706 u32 tsid,
1707 u16 orig_tclass,
1708 u16 specified,
1709 const char *objname,
1710 u32 *out_sid,
1711 bool kern)
1712 {
1713 struct selinux_policy *policy;
1714 struct policydb *policydb;
1715 struct sidtab *sidtab;
1716 struct class_datum *cladatum;
1717 struct context *scontext, *tcontext, newcontext;
1718 struct sidtab_entry *sentry, *tentry;
1719 struct avtab_key avkey;
1720 struct avtab_node *avnode, *node;
1721 u16 tclass;
1722 int rc = 0;
1723 bool sock;
1724
1725 if (!selinux_initialized()) {
1726 switch (orig_tclass) {
1727 case SECCLASS_PROCESS: /* kernel value */
1728 *out_sid = ssid;
1729 break;
1730 default:
1731 *out_sid = tsid;
1732 break;
1733 }
1734 goto out;
1735 }
1736
1737 retry:
1738 cladatum = NULL;
1739 context_init(&newcontext);
1740
1741 rcu_read_lock();
1742
1743 policy = rcu_dereference(selinux_state.policy);
1744
1745 if (kern) {
1746 tclass = unmap_class(&policy->map, orig_tclass);
1747 sock = security_is_socket_class(orig_tclass);
1748 } else {
1749 tclass = orig_tclass;
1750 sock = security_is_socket_class(map_class(&policy->map,
1751 tclass));
1752 }
1753
1754 policydb = &policy->policydb;
1755 sidtab = policy->sidtab;
1756
1757 sentry = sidtab_search_entry(sidtab, ssid);
1758 if (!sentry) {
1759 pr_err("SELinux: %s: unrecognized SID %d\n",
1760 __func__, ssid);
1761 rc = -EINVAL;
1762 goto out_unlock;
1763 }
1764 tentry = sidtab_search_entry(sidtab, tsid);
1765 if (!tentry) {
1766 pr_err("SELinux: %s: unrecognized SID %d\n",
1767 __func__, tsid);
1768 rc = -EINVAL;
1769 goto out_unlock;
1770 }
1771
1772 scontext = &sentry->context;
1773 tcontext = &tentry->context;
1774
1775 if (tclass && tclass <= policydb->p_classes.nprim)
1776 cladatum = policydb->class_val_to_struct[tclass - 1];
1777
1778 /* Set the user identity. */
1779 switch (specified) {
1780 case AVTAB_TRANSITION:
1781 case AVTAB_CHANGE:
1782 if (cladatum && cladatum->default_user == DEFAULT_TARGET) {
1783 newcontext.user = tcontext->user;
1784 } else {
1785 /* notice this gets both DEFAULT_SOURCE and unset */
1786 /* Use the process user identity. */
1787 newcontext.user = scontext->user;
1788 }
1789 break;
1790 case AVTAB_MEMBER:
1791 /* Use the related object owner. */
1792 newcontext.user = tcontext->user;
1793 break;
1794 }
1795
1796 /* Set the role to default values. */
1797 if (cladatum && cladatum->default_role == DEFAULT_SOURCE) {
1798 newcontext.role = scontext->role;
1799 } else if (cladatum && cladatum->default_role == DEFAULT_TARGET) {
1800 newcontext.role = tcontext->role;
1801 } else {
1802 if ((tclass == policydb->process_class) || sock)
1803 newcontext.role = scontext->role;
1804 else
1805 newcontext.role = OBJECT_R_VAL;
1806 }
1807
1808 /* Set the type to default values. */
1809 if (cladatum && cladatum->default_type == DEFAULT_SOURCE) {
1810 newcontext.type = scontext->type;
1811 } else if (cladatum && cladatum->default_type == DEFAULT_TARGET) {
1812 newcontext.type = tcontext->type;
1813 } else {
1814 if ((tclass == policydb->process_class) || sock) {
1815 /* Use the type of process. */
1816 newcontext.type = scontext->type;
1817 } else {
1818 /* Use the type of the related object. */
1819 newcontext.type = tcontext->type;
1820 }
1821 }
1822
1823 /* Look for a type transition/member/change rule. */
1824 avkey.source_type = scontext->type;
1825 avkey.target_type = tcontext->type;
1826 avkey.target_class = tclass;
1827 avkey.specified = specified;
1828 avnode = avtab_search_node(&policydb->te_avtab, &avkey);
1829
1830 /* If no permanent rule, also check for enabled conditional rules */
1831 if (!avnode) {
1832 node = avtab_search_node(&policydb->te_cond_avtab, &avkey);
1833 for (; node; node = avtab_search_node_next(node, specified)) {
1834 if (node->key.specified & AVTAB_ENABLED) {
1835 avnode = node;
1836 break;
1837 }
1838 }
1839 }
1840
1841 if (avnode) {
1842 /* Use the type from the type transition/member/change rule. */
1843 newcontext.type = avnode->datum.u.data;
1844 }
1845
1846 /* if we have a objname this is a file trans check so check those rules */
1847 if (objname)
1848 filename_compute_type(policydb, &newcontext, scontext->type,
1849 tcontext->type, tclass, objname);
1850
1851 /* Check for class-specific changes. */
1852 if (specified & AVTAB_TRANSITION) {
1853 /* Look for a role transition rule. */
1854 struct role_trans_datum *rtd;
1855 struct role_trans_key rtk = {
1856 .role = scontext->role,
1857 .type = tcontext->type,
1858 .tclass = tclass,
1859 };
1860
1861 rtd = policydb_roletr_search(policydb, &rtk);
1862 if (rtd)
1863 newcontext.role = rtd->new_role;
1864 }
1865
1866 /* Set the MLS attributes.
1867 This is done last because it may allocate memory. */
1868 rc = mls_compute_sid(policydb, scontext, tcontext, tclass, specified,
1869 &newcontext, sock);
1870 if (rc)
1871 goto out_unlock;
1872
1873 /* Check the validity of the context. */
1874 if (!policydb_context_isvalid(policydb, &newcontext)) {
1875 rc = compute_sid_handle_invalid_context(policy, sentry,
1876 tentry, tclass,
1877 &newcontext);
1878 if (rc)
1879 goto out_unlock;
1880 }
1881 /* Obtain the sid for the context. */
1882 rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
1883 if (rc == -ESTALE) {
1884 rcu_read_unlock();
1885 context_destroy(&newcontext);
1886 goto retry;
1887 }
1888 out_unlock:
1889 rcu_read_unlock();
1890 context_destroy(&newcontext);
1891 out:
1892 return rc;
1893 }
1894
1895 /**
1896 * security_transition_sid - Compute the SID for a new subject/object.
1897 * @ssid: source security identifier
1898 * @tsid: target security identifier
1899 * @tclass: target security class
1900 * @qstr: object name
1901 * @out_sid: security identifier for new subject/object
1902 *
1903 * Compute a SID to use for labeling a new subject or object in the
1904 * class @tclass based on a SID pair (@ssid, @tsid).
1905 * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1906 * if insufficient memory is available, or %0 if the new SID was
1907 * computed successfully.
1908 */
security_transition_sid(u32 ssid,u32 tsid,u16 tclass,const struct qstr * qstr,u32 * out_sid)1909 int security_transition_sid(u32 ssid, u32 tsid, u16 tclass,
1910 const struct qstr *qstr, u32 *out_sid)
1911 {
1912 return security_compute_sid(ssid, tsid, tclass,
1913 AVTAB_TRANSITION,
1914 qstr ? qstr->name : NULL, out_sid, true);
1915 }
1916
security_transition_sid_user(u32 ssid,u32 tsid,u16 tclass,const char * objname,u32 * out_sid)1917 int security_transition_sid_user(u32 ssid, u32 tsid, u16 tclass,
1918 const char *objname, u32 *out_sid)
1919 {
1920 return security_compute_sid(ssid, tsid, tclass,
1921 AVTAB_TRANSITION,
1922 objname, out_sid, false);
1923 }
1924
1925 /**
1926 * security_member_sid - Compute the SID for member selection.
1927 * @ssid: source security identifier
1928 * @tsid: target security identifier
1929 * @tclass: target security class
1930 * @out_sid: security identifier for selected member
1931 *
1932 * Compute a SID to use when selecting a member of a polyinstantiated
1933 * object of class @tclass based on a SID pair (@ssid, @tsid).
1934 * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1935 * if insufficient memory is available, or %0 if the SID was
1936 * computed successfully.
1937 */
security_member_sid(u32 ssid,u32 tsid,u16 tclass,u32 * out_sid)1938 int security_member_sid(u32 ssid,
1939 u32 tsid,
1940 u16 tclass,
1941 u32 *out_sid)
1942 {
1943 return security_compute_sid(ssid, tsid, tclass,
1944 AVTAB_MEMBER, NULL,
1945 out_sid, false);
1946 }
1947
1948 /**
1949 * security_change_sid - Compute the SID for object relabeling.
1950 * @ssid: source security identifier
1951 * @tsid: target security identifier
1952 * @tclass: target security class
1953 * @out_sid: security identifier for selected member
1954 *
1955 * Compute a SID to use for relabeling an object of class @tclass
1956 * based on a SID pair (@ssid, @tsid).
1957 * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1958 * if insufficient memory is available, or %0 if the SID was
1959 * computed successfully.
1960 */
security_change_sid(u32 ssid,u32 tsid,u16 tclass,u32 * out_sid)1961 int security_change_sid(u32 ssid,
1962 u32 tsid,
1963 u16 tclass,
1964 u32 *out_sid)
1965 {
1966 return security_compute_sid(ssid, tsid, tclass, AVTAB_CHANGE, NULL,
1967 out_sid, false);
1968 }
1969
convert_context_handle_invalid_context(struct policydb * policydb,struct context * context)1970 static inline int convert_context_handle_invalid_context(
1971 struct policydb *policydb,
1972 struct context *context)
1973 {
1974 char *s;
1975 u32 len;
1976
1977 if (enforcing_enabled())
1978 return -EINVAL;
1979
1980 if (!context_struct_to_string(policydb, context, &s, &len)) {
1981 pr_warn("SELinux: Context %s would be invalid if enforcing\n",
1982 s);
1983 kfree(s);
1984 }
1985 return 0;
1986 }
1987
1988 /**
1989 * services_convert_context - Convert a security context across policies.
1990 * @args: populated convert_context_args struct
1991 * @oldc: original context
1992 * @newc: converted context
1993 * @gfp_flags: allocation flags
1994 *
1995 * Convert the values in the security context structure @oldc from the values
1996 * specified in the policy @args->oldp to the values specified in the policy
1997 * @args->newp, storing the new context in @newc, and verifying that the
1998 * context is valid under the new policy.
1999 */
services_convert_context(struct convert_context_args * args,struct context * oldc,struct context * newc,gfp_t gfp_flags)2000 int services_convert_context(struct convert_context_args *args,
2001 struct context *oldc, struct context *newc,
2002 gfp_t gfp_flags)
2003 {
2004 struct ocontext *oc;
2005 struct role_datum *role;
2006 struct type_datum *typdatum;
2007 struct user_datum *usrdatum;
2008 char *s;
2009 u32 len;
2010 int rc;
2011
2012 if (oldc->str) {
2013 s = kstrdup(oldc->str, gfp_flags);
2014 if (!s)
2015 return -ENOMEM;
2016
2017 rc = string_to_context_struct(args->newp, NULL, s, newc, SECSID_NULL);
2018 if (rc == -EINVAL) {
2019 /*
2020 * Retain string representation for later mapping.
2021 *
2022 * IMPORTANT: We need to copy the contents of oldc->str
2023 * back into s again because string_to_context_struct()
2024 * may have garbled it.
2025 */
2026 memcpy(s, oldc->str, oldc->len);
2027 context_init(newc);
2028 newc->str = s;
2029 newc->len = oldc->len;
2030 return 0;
2031 }
2032 kfree(s);
2033 if (rc) {
2034 /* Other error condition, e.g. ENOMEM. */
2035 pr_err("SELinux: Unable to map context %s, rc = %d.\n",
2036 oldc->str, -rc);
2037 return rc;
2038 }
2039 pr_info("SELinux: Context %s became valid (mapped).\n",
2040 oldc->str);
2041 return 0;
2042 }
2043
2044 context_init(newc);
2045
2046 /* Convert the user. */
2047 usrdatum = symtab_search(&args->newp->p_users,
2048 sym_name(args->oldp, SYM_USERS, oldc->user - 1));
2049 if (!usrdatum)
2050 goto bad;
2051 newc->user = usrdatum->value;
2052
2053 /* Convert the role. */
2054 role = symtab_search(&args->newp->p_roles,
2055 sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
2056 if (!role)
2057 goto bad;
2058 newc->role = role->value;
2059
2060 /* Convert the type. */
2061 typdatum = symtab_search(&args->newp->p_types,
2062 sym_name(args->oldp, SYM_TYPES, oldc->type - 1));
2063 if (!typdatum)
2064 goto bad;
2065 newc->type = typdatum->value;
2066
2067 /* Convert the MLS fields if dealing with MLS policies */
2068 if (args->oldp->mls_enabled && args->newp->mls_enabled) {
2069 rc = mls_convert_context(args->oldp, args->newp, oldc, newc);
2070 if (rc)
2071 goto bad;
2072 } else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
2073 /*
2074 * Switching between non-MLS and MLS policy:
2075 * ensure that the MLS fields of the context for all
2076 * existing entries in the sidtab are filled in with a
2077 * suitable default value, likely taken from one of the
2078 * initial SIDs.
2079 */
2080 oc = args->newp->ocontexts[OCON_ISID];
2081 while (oc && oc->sid[0] != SECINITSID_UNLABELED)
2082 oc = oc->next;
2083 if (!oc) {
2084 pr_err("SELinux: unable to look up"
2085 " the initial SIDs list\n");
2086 goto bad;
2087 }
2088 rc = mls_range_set(newc, &oc->context[0].range);
2089 if (rc)
2090 goto bad;
2091 }
2092
2093 /* Check the validity of the new context. */
2094 if (!policydb_context_isvalid(args->newp, newc)) {
2095 rc = convert_context_handle_invalid_context(args->oldp, oldc);
2096 if (rc)
2097 goto bad;
2098 }
2099
2100 return 0;
2101 bad:
2102 /* Map old representation to string and save it. */
2103 rc = context_struct_to_string(args->oldp, oldc, &s, &len);
2104 if (rc)
2105 return rc;
2106 context_destroy(newc);
2107 newc->str = s;
2108 newc->len = len;
2109 pr_info("SELinux: Context %s became invalid (unmapped).\n",
2110 newc->str);
2111 return 0;
2112 }
2113
security_load_policycaps(struct selinux_policy * policy)2114 static void security_load_policycaps(struct selinux_policy *policy)
2115 {
2116 struct policydb *p;
2117 unsigned int i;
2118 struct ebitmap_node *node;
2119
2120 p = &policy->policydb;
2121
2122 for (i = 0; i < ARRAY_SIZE(selinux_state.policycap); i++)
2123 WRITE_ONCE(selinux_state.policycap[i],
2124 ebitmap_get_bit(&p->policycaps, i));
2125
2126 for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
2127 pr_info("SELinux: policy capability %s=%d\n",
2128 selinux_policycap_names[i],
2129 ebitmap_get_bit(&p->policycaps, i));
2130
2131 ebitmap_for_each_positive_bit(&p->policycaps, node, i) {
2132 if (i >= ARRAY_SIZE(selinux_policycap_names))
2133 pr_info("SELinux: unknown policy capability %u\n",
2134 i);
2135 }
2136 }
2137
2138 static int security_preserve_bools(struct selinux_policy *oldpolicy,
2139 struct selinux_policy *newpolicy);
2140
selinux_policy_free(struct selinux_policy * policy)2141 static void selinux_policy_free(struct selinux_policy *policy)
2142 {
2143 if (!policy)
2144 return;
2145
2146 sidtab_destroy(policy->sidtab);
2147 kfree(policy->map.mapping);
2148 policydb_destroy(&policy->policydb);
2149 kfree(policy->sidtab);
2150 kfree(policy);
2151 }
2152
selinux_policy_cond_free(struct selinux_policy * policy)2153 static void selinux_policy_cond_free(struct selinux_policy *policy)
2154 {
2155 cond_policydb_destroy_dup(&policy->policydb);
2156 kfree(policy);
2157 }
2158
selinux_policy_cancel(struct selinux_load_state * load_state)2159 void selinux_policy_cancel(struct selinux_load_state *load_state)
2160 {
2161 struct selinux_state *state = &selinux_state;
2162 struct selinux_policy *oldpolicy;
2163
2164 oldpolicy = rcu_dereference_protected(state->policy,
2165 lockdep_is_held(&state->policy_mutex));
2166
2167 sidtab_cancel_convert(oldpolicy->sidtab);
2168 selinux_policy_free(load_state->policy);
2169 kfree(load_state->convert_data);
2170 }
2171
selinux_notify_policy_change(u32 seqno)2172 static void selinux_notify_policy_change(u32 seqno)
2173 {
2174 /* Flush external caches and notify userspace of policy load */
2175 avc_ss_reset(seqno);
2176 selnl_notify_policyload(seqno);
2177 selinux_status_update_policyload(seqno);
2178 selinux_netlbl_cache_invalidate();
2179 selinux_xfrm_notify_policyload();
2180 selinux_ima_measure_state_locked();
2181 }
2182
selinux_policy_commit(struct selinux_load_state * load_state)2183 void selinux_policy_commit(struct selinux_load_state *load_state)
2184 {
2185 struct selinux_state *state = &selinux_state;
2186 struct selinux_policy *oldpolicy, *newpolicy = load_state->policy;
2187 unsigned long flags;
2188 u32 seqno;
2189
2190 oldpolicy = rcu_dereference_protected(state->policy,
2191 lockdep_is_held(&state->policy_mutex));
2192
2193 /* If switching between different policy types, log MLS status */
2194 if (oldpolicy) {
2195 if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
2196 pr_info("SELinux: Disabling MLS support...\n");
2197 else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
2198 pr_info("SELinux: Enabling MLS support...\n");
2199 }
2200
2201 /* Set latest granting seqno for new policy. */
2202 if (oldpolicy)
2203 newpolicy->latest_granting = oldpolicy->latest_granting + 1;
2204 else
2205 newpolicy->latest_granting = 1;
2206 seqno = newpolicy->latest_granting;
2207
2208 /* Install the new policy. */
2209 if (oldpolicy) {
2210 sidtab_freeze_begin(oldpolicy->sidtab, &flags);
2211 rcu_assign_pointer(state->policy, newpolicy);
2212 sidtab_freeze_end(oldpolicy->sidtab, &flags);
2213 } else {
2214 rcu_assign_pointer(state->policy, newpolicy);
2215 }
2216
2217 /* Load the policycaps from the new policy */
2218 security_load_policycaps(newpolicy);
2219
2220 if (!selinux_initialized()) {
2221 /*
2222 * After first policy load, the security server is
2223 * marked as initialized and ready to handle requests and
2224 * any objects created prior to policy load are then labeled.
2225 */
2226 selinux_mark_initialized();
2227 selinux_complete_init();
2228 }
2229
2230 /* Free the old policy */
2231 synchronize_rcu();
2232 selinux_policy_free(oldpolicy);
2233 kfree(load_state->convert_data);
2234
2235 /* Notify others of the policy change */
2236 selinux_notify_policy_change(seqno);
2237 }
2238
2239 /**
2240 * security_load_policy - Load a security policy configuration.
2241 * @data: binary policy data
2242 * @len: length of data in bytes
2243 * @load_state: policy load state
2244 *
2245 * Load a new set of security policy configuration data,
2246 * validate it and convert the SID table as necessary.
2247 * This function will flush the access vector cache after
2248 * loading the new policy.
2249 */
security_load_policy(void * data,size_t len,struct selinux_load_state * load_state)2250 int security_load_policy(void *data, size_t len,
2251 struct selinux_load_state *load_state)
2252 {
2253 struct selinux_state *state = &selinux_state;
2254 struct selinux_policy *newpolicy, *oldpolicy;
2255 struct selinux_policy_convert_data *convert_data;
2256 int rc = 0;
2257 struct policy_file file = { data, len }, *fp = &file;
2258
2259 newpolicy = kzalloc(sizeof(*newpolicy), GFP_KERNEL);
2260 if (!newpolicy)
2261 return -ENOMEM;
2262
2263 newpolicy->sidtab = kzalloc(sizeof(*newpolicy->sidtab), GFP_KERNEL);
2264 if (!newpolicy->sidtab) {
2265 rc = -ENOMEM;
2266 goto err_policy;
2267 }
2268
2269 rc = policydb_read(&newpolicy->policydb, fp);
2270 if (rc)
2271 goto err_sidtab;
2272
2273 newpolicy->policydb.len = len;
2274 rc = selinux_set_mapping(&newpolicy->policydb, secclass_map,
2275 &newpolicy->map);
2276 if (rc)
2277 goto err_policydb;
2278
2279 rc = policydb_load_isids(&newpolicy->policydb, newpolicy->sidtab);
2280 if (rc) {
2281 pr_err("SELinux: unable to load the initial SIDs\n");
2282 goto err_mapping;
2283 }
2284
2285 if (!selinux_initialized()) {
2286 /* First policy load, so no need to preserve state from old policy */
2287 load_state->policy = newpolicy;
2288 load_state->convert_data = NULL;
2289 return 0;
2290 }
2291
2292 oldpolicy = rcu_dereference_protected(state->policy,
2293 lockdep_is_held(&state->policy_mutex));
2294
2295 /* Preserve active boolean values from the old policy */
2296 rc = security_preserve_bools(oldpolicy, newpolicy);
2297 if (rc) {
2298 pr_err("SELinux: unable to preserve booleans\n");
2299 goto err_free_isids;
2300 }
2301
2302 /*
2303 * Convert the internal representations of contexts
2304 * in the new SID table.
2305 */
2306
2307 convert_data = kmalloc(sizeof(*convert_data), GFP_KERNEL);
2308 if (!convert_data) {
2309 rc = -ENOMEM;
2310 goto err_free_isids;
2311 }
2312
2313 convert_data->args.oldp = &oldpolicy->policydb;
2314 convert_data->args.newp = &newpolicy->policydb;
2315
2316 convert_data->sidtab_params.args = &convert_data->args;
2317 convert_data->sidtab_params.target = newpolicy->sidtab;
2318
2319 rc = sidtab_convert(oldpolicy->sidtab, &convert_data->sidtab_params);
2320 if (rc) {
2321 pr_err("SELinux: unable to convert the internal"
2322 " representation of contexts in the new SID"
2323 " table\n");
2324 goto err_free_convert_data;
2325 }
2326
2327 load_state->policy = newpolicy;
2328 load_state->convert_data = convert_data;
2329 return 0;
2330
2331 err_free_convert_data:
2332 kfree(convert_data);
2333 err_free_isids:
2334 sidtab_destroy(newpolicy->sidtab);
2335 err_mapping:
2336 kfree(newpolicy->map.mapping);
2337 err_policydb:
2338 policydb_destroy(&newpolicy->policydb);
2339 err_sidtab:
2340 kfree(newpolicy->sidtab);
2341 err_policy:
2342 kfree(newpolicy);
2343
2344 return rc;
2345 }
2346
2347 /**
2348 * ocontext_to_sid - Helper to safely get sid for an ocontext
2349 * @sidtab: SID table
2350 * @c: ocontext structure
2351 * @index: index of the context entry (0 or 1)
2352 * @out_sid: pointer to the resulting SID value
2353 *
2354 * For all ocontexts except OCON_ISID the SID fields are populated
2355 * on-demand when needed. Since updating the SID value is an SMP-sensitive
2356 * operation, this helper must be used to do that safely.
2357 *
2358 * WARNING: This function may return -ESTALE, indicating that the caller
2359 * must retry the operation after re-acquiring the policy pointer!
2360 */
ocontext_to_sid(struct sidtab * sidtab,struct ocontext * c,size_t index,u32 * out_sid)2361 static int ocontext_to_sid(struct sidtab *sidtab, struct ocontext *c,
2362 size_t index, u32 *out_sid)
2363 {
2364 int rc;
2365 u32 sid;
2366
2367 /* Ensure the associated sidtab entry is visible to this thread. */
2368 sid = smp_load_acquire(&c->sid[index]);
2369 if (!sid) {
2370 rc = sidtab_context_to_sid(sidtab, &c->context[index], &sid);
2371 if (rc)
2372 return rc;
2373
2374 /*
2375 * Ensure the new sidtab entry is visible to other threads
2376 * when they see the SID.
2377 */
2378 smp_store_release(&c->sid[index], sid);
2379 }
2380 *out_sid = sid;
2381 return 0;
2382 }
2383
2384 /**
2385 * security_port_sid - Obtain the SID for a port.
2386 * @protocol: protocol number
2387 * @port: port number
2388 * @out_sid: security identifier
2389 */
security_port_sid(u8 protocol,u16 port,u32 * out_sid)2390 int security_port_sid(u8 protocol, u16 port, u32 *out_sid)
2391 {
2392 struct selinux_policy *policy;
2393 struct policydb *policydb;
2394 struct sidtab *sidtab;
2395 struct ocontext *c;
2396 int rc;
2397
2398 if (!selinux_initialized()) {
2399 *out_sid = SECINITSID_PORT;
2400 return 0;
2401 }
2402
2403 retry:
2404 rc = 0;
2405 rcu_read_lock();
2406 policy = rcu_dereference(selinux_state.policy);
2407 policydb = &policy->policydb;
2408 sidtab = policy->sidtab;
2409
2410 c = policydb->ocontexts[OCON_PORT];
2411 while (c) {
2412 if (c->u.port.protocol == protocol &&
2413 c->u.port.low_port <= port &&
2414 c->u.port.high_port >= port)
2415 break;
2416 c = c->next;
2417 }
2418
2419 if (c) {
2420 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2421 if (rc == -ESTALE) {
2422 rcu_read_unlock();
2423 goto retry;
2424 }
2425 if (rc)
2426 goto out;
2427 } else {
2428 *out_sid = SECINITSID_PORT;
2429 }
2430
2431 out:
2432 rcu_read_unlock();
2433 return rc;
2434 }
2435
2436 /**
2437 * security_ib_pkey_sid - Obtain the SID for a pkey.
2438 * @subnet_prefix: Subnet Prefix
2439 * @pkey_num: pkey number
2440 * @out_sid: security identifier
2441 */
security_ib_pkey_sid(u64 subnet_prefix,u16 pkey_num,u32 * out_sid)2442 int security_ib_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
2443 {
2444 struct selinux_policy *policy;
2445 struct policydb *policydb;
2446 struct sidtab *sidtab;
2447 struct ocontext *c;
2448 int rc;
2449
2450 if (!selinux_initialized()) {
2451 *out_sid = SECINITSID_UNLABELED;
2452 return 0;
2453 }
2454
2455 retry:
2456 rc = 0;
2457 rcu_read_lock();
2458 policy = rcu_dereference(selinux_state.policy);
2459 policydb = &policy->policydb;
2460 sidtab = policy->sidtab;
2461
2462 c = policydb->ocontexts[OCON_IBPKEY];
2463 while (c) {
2464 if (c->u.ibpkey.low_pkey <= pkey_num &&
2465 c->u.ibpkey.high_pkey >= pkey_num &&
2466 c->u.ibpkey.subnet_prefix == subnet_prefix)
2467 break;
2468
2469 c = c->next;
2470 }
2471
2472 if (c) {
2473 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2474 if (rc == -ESTALE) {
2475 rcu_read_unlock();
2476 goto retry;
2477 }
2478 if (rc)
2479 goto out;
2480 } else
2481 *out_sid = SECINITSID_UNLABELED;
2482
2483 out:
2484 rcu_read_unlock();
2485 return rc;
2486 }
2487
2488 /**
2489 * security_ib_endport_sid - Obtain the SID for a subnet management interface.
2490 * @dev_name: device name
2491 * @port_num: port number
2492 * @out_sid: security identifier
2493 */
security_ib_endport_sid(const char * dev_name,u8 port_num,u32 * out_sid)2494 int security_ib_endport_sid(const char *dev_name, u8 port_num, u32 *out_sid)
2495 {
2496 struct selinux_policy *policy;
2497 struct policydb *policydb;
2498 struct sidtab *sidtab;
2499 struct ocontext *c;
2500 int rc;
2501
2502 if (!selinux_initialized()) {
2503 *out_sid = SECINITSID_UNLABELED;
2504 return 0;
2505 }
2506
2507 retry:
2508 rc = 0;
2509 rcu_read_lock();
2510 policy = rcu_dereference(selinux_state.policy);
2511 policydb = &policy->policydb;
2512 sidtab = policy->sidtab;
2513
2514 c = policydb->ocontexts[OCON_IBENDPORT];
2515 while (c) {
2516 if (c->u.ibendport.port == port_num &&
2517 !strncmp(c->u.ibendport.dev_name,
2518 dev_name,
2519 IB_DEVICE_NAME_MAX))
2520 break;
2521
2522 c = c->next;
2523 }
2524
2525 if (c) {
2526 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2527 if (rc == -ESTALE) {
2528 rcu_read_unlock();
2529 goto retry;
2530 }
2531 if (rc)
2532 goto out;
2533 } else
2534 *out_sid = SECINITSID_UNLABELED;
2535
2536 out:
2537 rcu_read_unlock();
2538 return rc;
2539 }
2540
2541 /**
2542 * security_netif_sid - Obtain the SID for a network interface.
2543 * @name: interface name
2544 * @if_sid: interface SID
2545 */
security_netif_sid(char * name,u32 * if_sid)2546 int security_netif_sid(char *name, u32 *if_sid)
2547 {
2548 struct selinux_policy *policy;
2549 struct policydb *policydb;
2550 struct sidtab *sidtab;
2551 int rc;
2552 struct ocontext *c;
2553
2554 if (!selinux_initialized()) {
2555 *if_sid = SECINITSID_NETIF;
2556 return 0;
2557 }
2558
2559 retry:
2560 rc = 0;
2561 rcu_read_lock();
2562 policy = rcu_dereference(selinux_state.policy);
2563 policydb = &policy->policydb;
2564 sidtab = policy->sidtab;
2565
2566 c = policydb->ocontexts[OCON_NETIF];
2567 while (c) {
2568 if (strcmp(name, c->u.name) == 0)
2569 break;
2570 c = c->next;
2571 }
2572
2573 if (c) {
2574 rc = ocontext_to_sid(sidtab, c, 0, if_sid);
2575 if (rc == -ESTALE) {
2576 rcu_read_unlock();
2577 goto retry;
2578 }
2579 if (rc)
2580 goto out;
2581 } else
2582 *if_sid = SECINITSID_NETIF;
2583
2584 out:
2585 rcu_read_unlock();
2586 return rc;
2587 }
2588
match_ipv6_addrmask(u32 * input,u32 * addr,u32 * mask)2589 static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask)
2590 {
2591 int i, fail = 0;
2592
2593 for (i = 0; i < 4; i++)
2594 if (addr[i] != (input[i] & mask[i])) {
2595 fail = 1;
2596 break;
2597 }
2598
2599 return !fail;
2600 }
2601
2602 /**
2603 * security_node_sid - Obtain the SID for a node (host).
2604 * @domain: communication domain aka address family
2605 * @addrp: address
2606 * @addrlen: address length in bytes
2607 * @out_sid: security identifier
2608 */
security_node_sid(u16 domain,void * addrp,u32 addrlen,u32 * out_sid)2609 int security_node_sid(u16 domain,
2610 void *addrp,
2611 u32 addrlen,
2612 u32 *out_sid)
2613 {
2614 struct selinux_policy *policy;
2615 struct policydb *policydb;
2616 struct sidtab *sidtab;
2617 int rc;
2618 struct ocontext *c;
2619
2620 if (!selinux_initialized()) {
2621 *out_sid = SECINITSID_NODE;
2622 return 0;
2623 }
2624
2625 retry:
2626 rcu_read_lock();
2627 policy = rcu_dereference(selinux_state.policy);
2628 policydb = &policy->policydb;
2629 sidtab = policy->sidtab;
2630
2631 switch (domain) {
2632 case AF_INET: {
2633 u32 addr;
2634
2635 rc = -EINVAL;
2636 if (addrlen != sizeof(u32))
2637 goto out;
2638
2639 addr = *((u32 *)addrp);
2640
2641 c = policydb->ocontexts[OCON_NODE];
2642 while (c) {
2643 if (c->u.node.addr == (addr & c->u.node.mask))
2644 break;
2645 c = c->next;
2646 }
2647 break;
2648 }
2649
2650 case AF_INET6:
2651 rc = -EINVAL;
2652 if (addrlen != sizeof(u64) * 2)
2653 goto out;
2654 c = policydb->ocontexts[OCON_NODE6];
2655 while (c) {
2656 if (match_ipv6_addrmask(addrp, c->u.node6.addr,
2657 c->u.node6.mask))
2658 break;
2659 c = c->next;
2660 }
2661 break;
2662
2663 default:
2664 rc = 0;
2665 *out_sid = SECINITSID_NODE;
2666 goto out;
2667 }
2668
2669 if (c) {
2670 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2671 if (rc == -ESTALE) {
2672 rcu_read_unlock();
2673 goto retry;
2674 }
2675 if (rc)
2676 goto out;
2677 } else {
2678 *out_sid = SECINITSID_NODE;
2679 }
2680
2681 rc = 0;
2682 out:
2683 rcu_read_unlock();
2684 return rc;
2685 }
2686
2687 #define SIDS_NEL 25
2688
2689 /**
2690 * security_get_user_sids - Obtain reachable SIDs for a user.
2691 * @fromsid: starting SID
2692 * @username: username
2693 * @sids: array of reachable SIDs for user
2694 * @nel: number of elements in @sids
2695 *
2696 * Generate the set of SIDs for legal security contexts
2697 * for a given user that can be reached by @fromsid.
2698 * Set *@sids to point to a dynamically allocated
2699 * array containing the set of SIDs. Set *@nel to the
2700 * number of elements in the array.
2701 */
2702
security_get_user_sids(u32 fromsid,char * username,u32 ** sids,u32 * nel)2703 int security_get_user_sids(u32 fromsid,
2704 char *username,
2705 u32 **sids,
2706 u32 *nel)
2707 {
2708 struct selinux_policy *policy;
2709 struct policydb *policydb;
2710 struct sidtab *sidtab;
2711 struct context *fromcon, usercon;
2712 u32 *mysids = NULL, *mysids2, sid;
2713 u32 i, j, mynel, maxnel = SIDS_NEL;
2714 struct user_datum *user;
2715 struct role_datum *role;
2716 struct ebitmap_node *rnode, *tnode;
2717 int rc;
2718
2719 *sids = NULL;
2720 *nel = 0;
2721
2722 if (!selinux_initialized())
2723 return 0;
2724
2725 mysids = kcalloc(maxnel, sizeof(*mysids), GFP_KERNEL);
2726 if (!mysids)
2727 return -ENOMEM;
2728
2729 retry:
2730 mynel = 0;
2731 rcu_read_lock();
2732 policy = rcu_dereference(selinux_state.policy);
2733 policydb = &policy->policydb;
2734 sidtab = policy->sidtab;
2735
2736 context_init(&usercon);
2737
2738 rc = -EINVAL;
2739 fromcon = sidtab_search(sidtab, fromsid);
2740 if (!fromcon)
2741 goto out_unlock;
2742
2743 rc = -EINVAL;
2744 user = symtab_search(&policydb->p_users, username);
2745 if (!user)
2746 goto out_unlock;
2747
2748 usercon.user = user->value;
2749
2750 ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
2751 role = policydb->role_val_to_struct[i];
2752 usercon.role = i + 1;
2753 ebitmap_for_each_positive_bit(&role->types, tnode, j) {
2754 usercon.type = j + 1;
2755
2756 if (mls_setup_user_range(policydb, fromcon, user,
2757 &usercon))
2758 continue;
2759
2760 rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
2761 if (rc == -ESTALE) {
2762 rcu_read_unlock();
2763 goto retry;
2764 }
2765 if (rc)
2766 goto out_unlock;
2767 if (mynel < maxnel) {
2768 mysids[mynel++] = sid;
2769 } else {
2770 rc = -ENOMEM;
2771 maxnel += SIDS_NEL;
2772 mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
2773 if (!mysids2)
2774 goto out_unlock;
2775 memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
2776 kfree(mysids);
2777 mysids = mysids2;
2778 mysids[mynel++] = sid;
2779 }
2780 }
2781 }
2782 rc = 0;
2783 out_unlock:
2784 rcu_read_unlock();
2785 if (rc || !mynel) {
2786 kfree(mysids);
2787 return rc;
2788 }
2789
2790 rc = -ENOMEM;
2791 mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
2792 if (!mysids2) {
2793 kfree(mysids);
2794 return rc;
2795 }
2796 for (i = 0, j = 0; i < mynel; i++) {
2797 struct av_decision dummy_avd;
2798 rc = avc_has_perm_noaudit(fromsid, mysids[i],
2799 SECCLASS_PROCESS, /* kernel value */
2800 PROCESS__TRANSITION, AVC_STRICT,
2801 &dummy_avd);
2802 if (!rc)
2803 mysids2[j++] = mysids[i];
2804 cond_resched();
2805 }
2806 kfree(mysids);
2807 *sids = mysids2;
2808 *nel = j;
2809 return 0;
2810 }
2811
2812 /**
2813 * __security_genfs_sid - Helper to obtain a SID for a file in a filesystem
2814 * @policy: policy
2815 * @fstype: filesystem type
2816 * @path: path from root of mount
2817 * @orig_sclass: file security class
2818 * @sid: SID for path
2819 *
2820 * Obtain a SID to use for a file in a filesystem that
2821 * cannot support xattr or use a fixed labeling behavior like
2822 * transition SIDs or task SIDs.
2823 *
2824 * WARNING: This function may return -ESTALE, indicating that the caller
2825 * must retry the operation after re-acquiring the policy pointer!
2826 */
__security_genfs_sid(struct selinux_policy * policy,const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2827 static inline int __security_genfs_sid(struct selinux_policy *policy,
2828 const char *fstype,
2829 const char *path,
2830 u16 orig_sclass,
2831 u32 *sid)
2832 {
2833 struct policydb *policydb = &policy->policydb;
2834 struct sidtab *sidtab = policy->sidtab;
2835 u16 sclass;
2836 struct genfs *genfs;
2837 struct ocontext *c;
2838 int cmp = 0;
2839
2840 while (path[0] == '/' && path[1] == '/')
2841 path++;
2842
2843 sclass = unmap_class(&policy->map, orig_sclass);
2844 *sid = SECINITSID_UNLABELED;
2845
2846 for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
2847 cmp = strcmp(fstype, genfs->fstype);
2848 if (cmp <= 0)
2849 break;
2850 }
2851
2852 if (!genfs || cmp)
2853 return -ENOENT;
2854
2855 for (c = genfs->head; c; c = c->next) {
2856 size_t len = strlen(c->u.name);
2857 if ((!c->v.sclass || sclass == c->v.sclass) &&
2858 (strncmp(c->u.name, path, len) == 0))
2859 break;
2860 }
2861
2862 if (!c)
2863 return -ENOENT;
2864
2865 return ocontext_to_sid(sidtab, c, 0, sid);
2866 }
2867
2868 /**
2869 * security_genfs_sid - Obtain a SID for a file in a filesystem
2870 * @fstype: filesystem type
2871 * @path: path from root of mount
2872 * @orig_sclass: file security class
2873 * @sid: SID for path
2874 *
2875 * Acquire policy_rwlock before calling __security_genfs_sid() and release
2876 * it afterward.
2877 */
security_genfs_sid(const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2878 int security_genfs_sid(const char *fstype,
2879 const char *path,
2880 u16 orig_sclass,
2881 u32 *sid)
2882 {
2883 struct selinux_policy *policy;
2884 int retval;
2885
2886 if (!selinux_initialized()) {
2887 *sid = SECINITSID_UNLABELED;
2888 return 0;
2889 }
2890
2891 do {
2892 rcu_read_lock();
2893 policy = rcu_dereference(selinux_state.policy);
2894 retval = __security_genfs_sid(policy, fstype, path,
2895 orig_sclass, sid);
2896 rcu_read_unlock();
2897 } while (retval == -ESTALE);
2898 return retval;
2899 }
2900
selinux_policy_genfs_sid(struct selinux_policy * policy,const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2901 int selinux_policy_genfs_sid(struct selinux_policy *policy,
2902 const char *fstype,
2903 const char *path,
2904 u16 orig_sclass,
2905 u32 *sid)
2906 {
2907 /* no lock required, policy is not yet accessible by other threads */
2908 return __security_genfs_sid(policy, fstype, path, orig_sclass, sid);
2909 }
2910
2911 /**
2912 * security_fs_use - Determine how to handle labeling for a filesystem.
2913 * @sb: superblock in question
2914 */
security_fs_use(struct super_block * sb)2915 int security_fs_use(struct super_block *sb)
2916 {
2917 struct selinux_policy *policy;
2918 struct policydb *policydb;
2919 struct sidtab *sidtab;
2920 int rc;
2921 struct ocontext *c;
2922 struct superblock_security_struct *sbsec = selinux_superblock(sb);
2923 const char *fstype = sb->s_type->name;
2924
2925 if (!selinux_initialized()) {
2926 sbsec->behavior = SECURITY_FS_USE_NONE;
2927 sbsec->sid = SECINITSID_UNLABELED;
2928 return 0;
2929 }
2930
2931 retry:
2932 rcu_read_lock();
2933 policy = rcu_dereference(selinux_state.policy);
2934 policydb = &policy->policydb;
2935 sidtab = policy->sidtab;
2936
2937 c = policydb->ocontexts[OCON_FSUSE];
2938 while (c) {
2939 if (strcmp(fstype, c->u.name) == 0)
2940 break;
2941 c = c->next;
2942 }
2943
2944 if (c) {
2945 sbsec->behavior = c->v.behavior;
2946 rc = ocontext_to_sid(sidtab, c, 0, &sbsec->sid);
2947 if (rc == -ESTALE) {
2948 rcu_read_unlock();
2949 goto retry;
2950 }
2951 if (rc)
2952 goto out;
2953 } else {
2954 rc = __security_genfs_sid(policy, fstype, "/",
2955 SECCLASS_DIR, &sbsec->sid);
2956 if (rc == -ESTALE) {
2957 rcu_read_unlock();
2958 goto retry;
2959 }
2960 if (rc) {
2961 sbsec->behavior = SECURITY_FS_USE_NONE;
2962 rc = 0;
2963 } else {
2964 sbsec->behavior = SECURITY_FS_USE_GENFS;
2965 }
2966 }
2967
2968 out:
2969 rcu_read_unlock();
2970 return rc;
2971 }
2972
security_get_bools(struct selinux_policy * policy,u32 * len,char *** names,int ** values)2973 int security_get_bools(struct selinux_policy *policy,
2974 u32 *len, char ***names, int **values)
2975 {
2976 struct policydb *policydb;
2977 u32 i;
2978 int rc;
2979
2980 policydb = &policy->policydb;
2981
2982 *names = NULL;
2983 *values = NULL;
2984
2985 rc = 0;
2986 *len = policydb->p_bools.nprim;
2987 if (!*len)
2988 goto out;
2989
2990 rc = -ENOMEM;
2991 *names = kcalloc(*len, sizeof(char *), GFP_ATOMIC);
2992 if (!*names)
2993 goto err;
2994
2995 rc = -ENOMEM;
2996 *values = kcalloc(*len, sizeof(int), GFP_ATOMIC);
2997 if (!*values)
2998 goto err;
2999
3000 for (i = 0; i < *len; i++) {
3001 (*values)[i] = policydb->bool_val_to_struct[i]->state;
3002
3003 rc = -ENOMEM;
3004 (*names)[i] = kstrdup(sym_name(policydb, SYM_BOOLS, i),
3005 GFP_ATOMIC);
3006 if (!(*names)[i])
3007 goto err;
3008 }
3009 rc = 0;
3010 out:
3011 return rc;
3012 err:
3013 if (*names) {
3014 for (i = 0; i < *len; i++)
3015 kfree((*names)[i]);
3016 kfree(*names);
3017 }
3018 kfree(*values);
3019 *len = 0;
3020 *names = NULL;
3021 *values = NULL;
3022 goto out;
3023 }
3024
3025
security_set_bools(u32 len,int * values)3026 int security_set_bools(u32 len, int *values)
3027 {
3028 struct selinux_state *state = &selinux_state;
3029 struct selinux_policy *newpolicy, *oldpolicy;
3030 int rc;
3031 u32 i, seqno = 0;
3032
3033 if (!selinux_initialized())
3034 return -EINVAL;
3035
3036 oldpolicy = rcu_dereference_protected(state->policy,
3037 lockdep_is_held(&state->policy_mutex));
3038
3039 /* Consistency check on number of booleans, should never fail */
3040 if (WARN_ON(len != oldpolicy->policydb.p_bools.nprim))
3041 return -EINVAL;
3042
3043 newpolicy = kmemdup(oldpolicy, sizeof(*newpolicy), GFP_KERNEL);
3044 if (!newpolicy)
3045 return -ENOMEM;
3046
3047 /*
3048 * Deep copy only the parts of the policydb that might be
3049 * modified as a result of changing booleans.
3050 */
3051 rc = cond_policydb_dup(&newpolicy->policydb, &oldpolicy->policydb);
3052 if (rc) {
3053 kfree(newpolicy);
3054 return -ENOMEM;
3055 }
3056
3057 /* Update the boolean states in the copy */
3058 for (i = 0; i < len; i++) {
3059 int new_state = !!values[i];
3060 int old_state = newpolicy->policydb.bool_val_to_struct[i]->state;
3061
3062 if (new_state != old_state) {
3063 audit_log(audit_context(), GFP_ATOMIC,
3064 AUDIT_MAC_CONFIG_CHANGE,
3065 "bool=%s val=%d old_val=%d auid=%u ses=%u",
3066 sym_name(&newpolicy->policydb, SYM_BOOLS, i),
3067 new_state,
3068 old_state,
3069 from_kuid(&init_user_ns, audit_get_loginuid(current)),
3070 audit_get_sessionid(current));
3071 newpolicy->policydb.bool_val_to_struct[i]->state = new_state;
3072 }
3073 }
3074
3075 /* Re-evaluate the conditional rules in the copy */
3076 evaluate_cond_nodes(&newpolicy->policydb);
3077
3078 /* Set latest granting seqno for new policy */
3079 newpolicy->latest_granting = oldpolicy->latest_granting + 1;
3080 seqno = newpolicy->latest_granting;
3081
3082 /* Install the new policy */
3083 rcu_assign_pointer(state->policy, newpolicy);
3084
3085 /*
3086 * Free the conditional portions of the old policydb
3087 * that were copied for the new policy, and the oldpolicy
3088 * structure itself but not what it references.
3089 */
3090 synchronize_rcu();
3091 selinux_policy_cond_free(oldpolicy);
3092
3093 /* Notify others of the policy change */
3094 selinux_notify_policy_change(seqno);
3095 return 0;
3096 }
3097
security_get_bool_value(u32 index)3098 int security_get_bool_value(u32 index)
3099 {
3100 struct selinux_policy *policy;
3101 struct policydb *policydb;
3102 int rc;
3103 u32 len;
3104
3105 if (!selinux_initialized())
3106 return 0;
3107
3108 rcu_read_lock();
3109 policy = rcu_dereference(selinux_state.policy);
3110 policydb = &policy->policydb;
3111
3112 rc = -EFAULT;
3113 len = policydb->p_bools.nprim;
3114 if (index >= len)
3115 goto out;
3116
3117 rc = policydb->bool_val_to_struct[index]->state;
3118 out:
3119 rcu_read_unlock();
3120 return rc;
3121 }
3122
security_preserve_bools(struct selinux_policy * oldpolicy,struct selinux_policy * newpolicy)3123 static int security_preserve_bools(struct selinux_policy *oldpolicy,
3124 struct selinux_policy *newpolicy)
3125 {
3126 int rc, *bvalues = NULL;
3127 char **bnames = NULL;
3128 struct cond_bool_datum *booldatum;
3129 u32 i, nbools = 0;
3130
3131 rc = security_get_bools(oldpolicy, &nbools, &bnames, &bvalues);
3132 if (rc)
3133 goto out;
3134 for (i = 0; i < nbools; i++) {
3135 booldatum = symtab_search(&newpolicy->policydb.p_bools,
3136 bnames[i]);
3137 if (booldatum)
3138 booldatum->state = bvalues[i];
3139 }
3140 evaluate_cond_nodes(&newpolicy->policydb);
3141
3142 out:
3143 if (bnames) {
3144 for (i = 0; i < nbools; i++)
3145 kfree(bnames[i]);
3146 }
3147 kfree(bnames);
3148 kfree(bvalues);
3149 return rc;
3150 }
3151
3152 /*
3153 * security_sid_mls_copy() - computes a new sid based on the given
3154 * sid and the mls portion of mls_sid.
3155 */
security_sid_mls_copy(u32 sid,u32 mls_sid,u32 * new_sid)3156 int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid)
3157 {
3158 struct selinux_policy *policy;
3159 struct policydb *policydb;
3160 struct sidtab *sidtab;
3161 struct context *context1;
3162 struct context *context2;
3163 struct context newcon;
3164 char *s;
3165 u32 len;
3166 int rc;
3167
3168 if (!selinux_initialized()) {
3169 *new_sid = sid;
3170 return 0;
3171 }
3172
3173 retry:
3174 rc = 0;
3175 context_init(&newcon);
3176
3177 rcu_read_lock();
3178 policy = rcu_dereference(selinux_state.policy);
3179 policydb = &policy->policydb;
3180 sidtab = policy->sidtab;
3181
3182 if (!policydb->mls_enabled) {
3183 *new_sid = sid;
3184 goto out_unlock;
3185 }
3186
3187 rc = -EINVAL;
3188 context1 = sidtab_search(sidtab, sid);
3189 if (!context1) {
3190 pr_err("SELinux: %s: unrecognized SID %d\n",
3191 __func__, sid);
3192 goto out_unlock;
3193 }
3194
3195 rc = -EINVAL;
3196 context2 = sidtab_search(sidtab, mls_sid);
3197 if (!context2) {
3198 pr_err("SELinux: %s: unrecognized SID %d\n",
3199 __func__, mls_sid);
3200 goto out_unlock;
3201 }
3202
3203 newcon.user = context1->user;
3204 newcon.role = context1->role;
3205 newcon.type = context1->type;
3206 rc = mls_context_cpy(&newcon, context2);
3207 if (rc)
3208 goto out_unlock;
3209
3210 /* Check the validity of the new context. */
3211 if (!policydb_context_isvalid(policydb, &newcon)) {
3212 rc = convert_context_handle_invalid_context(policydb,
3213 &newcon);
3214 if (rc) {
3215 if (!context_struct_to_string(policydb, &newcon, &s,
3216 &len)) {
3217 struct audit_buffer *ab;
3218
3219 ab = audit_log_start(audit_context(),
3220 GFP_ATOMIC,
3221 AUDIT_SELINUX_ERR);
3222 audit_log_format(ab,
3223 "op=security_sid_mls_copy invalid_context=");
3224 /* don't record NUL with untrusted strings */
3225 audit_log_n_untrustedstring(ab, s, len - 1);
3226 audit_log_end(ab);
3227 kfree(s);
3228 }
3229 goto out_unlock;
3230 }
3231 }
3232 rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
3233 if (rc == -ESTALE) {
3234 rcu_read_unlock();
3235 context_destroy(&newcon);
3236 goto retry;
3237 }
3238 out_unlock:
3239 rcu_read_unlock();
3240 context_destroy(&newcon);
3241 return rc;
3242 }
3243
3244 /**
3245 * security_net_peersid_resolve - Compare and resolve two network peer SIDs
3246 * @nlbl_sid: NetLabel SID
3247 * @nlbl_type: NetLabel labeling protocol type
3248 * @xfrm_sid: XFRM SID
3249 * @peer_sid: network peer sid
3250 *
3251 * Description:
3252 * Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be
3253 * resolved into a single SID it is returned via @peer_sid and the function
3254 * returns zero. Otherwise @peer_sid is set to SECSID_NULL and the function
3255 * returns a negative value. A table summarizing the behavior is below:
3256 *
3257 * | function return | @sid
3258 * ------------------------------+-----------------+-----------------
3259 * no peer labels | 0 | SECSID_NULL
3260 * single peer label | 0 | <peer_label>
3261 * multiple, consistent labels | 0 | <peer_label>
3262 * multiple, inconsistent labels | -<errno> | SECSID_NULL
3263 *
3264 */
security_net_peersid_resolve(u32 nlbl_sid,u32 nlbl_type,u32 xfrm_sid,u32 * peer_sid)3265 int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type,
3266 u32 xfrm_sid,
3267 u32 *peer_sid)
3268 {
3269 struct selinux_policy *policy;
3270 struct policydb *policydb;
3271 struct sidtab *sidtab;
3272 int rc;
3273 struct context *nlbl_ctx;
3274 struct context *xfrm_ctx;
3275
3276 *peer_sid = SECSID_NULL;
3277
3278 /* handle the common (which also happens to be the set of easy) cases
3279 * right away, these two if statements catch everything involving a
3280 * single or absent peer SID/label */
3281 if (xfrm_sid == SECSID_NULL) {
3282 *peer_sid = nlbl_sid;
3283 return 0;
3284 }
3285 /* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label
3286 * and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label
3287 * is present */
3288 if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) {
3289 *peer_sid = xfrm_sid;
3290 return 0;
3291 }
3292
3293 if (!selinux_initialized())
3294 return 0;
3295
3296 rcu_read_lock();
3297 policy = rcu_dereference(selinux_state.policy);
3298 policydb = &policy->policydb;
3299 sidtab = policy->sidtab;
3300
3301 /*
3302 * We don't need to check initialized here since the only way both
3303 * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
3304 * security server was initialized and state->initialized was true.
3305 */
3306 if (!policydb->mls_enabled) {
3307 rc = 0;
3308 goto out;
3309 }
3310
3311 rc = -EINVAL;
3312 nlbl_ctx = sidtab_search(sidtab, nlbl_sid);
3313 if (!nlbl_ctx) {
3314 pr_err("SELinux: %s: unrecognized SID %d\n",
3315 __func__, nlbl_sid);
3316 goto out;
3317 }
3318 rc = -EINVAL;
3319 xfrm_ctx = sidtab_search(sidtab, xfrm_sid);
3320 if (!xfrm_ctx) {
3321 pr_err("SELinux: %s: unrecognized SID %d\n",
3322 __func__, xfrm_sid);
3323 goto out;
3324 }
3325 rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES);
3326 if (rc)
3327 goto out;
3328
3329 /* at present NetLabel SIDs/labels really only carry MLS
3330 * information so if the MLS portion of the NetLabel SID
3331 * matches the MLS portion of the labeled XFRM SID/label
3332 * then pass along the XFRM SID as it is the most
3333 * expressive */
3334 *peer_sid = xfrm_sid;
3335 out:
3336 rcu_read_unlock();
3337 return rc;
3338 }
3339
get_classes_callback(void * k,void * d,void * args)3340 static int get_classes_callback(void *k, void *d, void *args)
3341 {
3342 struct class_datum *datum = d;
3343 char *name = k, **classes = args;
3344 u32 value = datum->value - 1;
3345
3346 classes[value] = kstrdup(name, GFP_ATOMIC);
3347 if (!classes[value])
3348 return -ENOMEM;
3349
3350 return 0;
3351 }
3352
security_get_classes(struct selinux_policy * policy,char *** classes,u32 * nclasses)3353 int security_get_classes(struct selinux_policy *policy,
3354 char ***classes, u32 *nclasses)
3355 {
3356 struct policydb *policydb;
3357 int rc;
3358
3359 policydb = &policy->policydb;
3360
3361 rc = -ENOMEM;
3362 *nclasses = policydb->p_classes.nprim;
3363 *classes = kcalloc(*nclasses, sizeof(**classes), GFP_ATOMIC);
3364 if (!*classes)
3365 goto out;
3366
3367 rc = hashtab_map(&policydb->p_classes.table, get_classes_callback,
3368 *classes);
3369 if (rc) {
3370 u32 i;
3371
3372 for (i = 0; i < *nclasses; i++)
3373 kfree((*classes)[i]);
3374 kfree(*classes);
3375 }
3376
3377 out:
3378 return rc;
3379 }
3380
get_permissions_callback(void * k,void * d,void * args)3381 static int get_permissions_callback(void *k, void *d, void *args)
3382 {
3383 struct perm_datum *datum = d;
3384 char *name = k, **perms = args;
3385 u32 value = datum->value - 1;
3386
3387 perms[value] = kstrdup(name, GFP_ATOMIC);
3388 if (!perms[value])
3389 return -ENOMEM;
3390
3391 return 0;
3392 }
3393
security_get_permissions(struct selinux_policy * policy,const char * class,char *** perms,u32 * nperms)3394 int security_get_permissions(struct selinux_policy *policy,
3395 const char *class, char ***perms, u32 *nperms)
3396 {
3397 struct policydb *policydb;
3398 u32 i;
3399 int rc;
3400 struct class_datum *match;
3401
3402 policydb = &policy->policydb;
3403
3404 rc = -EINVAL;
3405 match = symtab_search(&policydb->p_classes, class);
3406 if (!match) {
3407 pr_err("SELinux: %s: unrecognized class %s\n",
3408 __func__, class);
3409 goto out;
3410 }
3411
3412 rc = -ENOMEM;
3413 *nperms = match->permissions.nprim;
3414 *perms = kcalloc(*nperms, sizeof(**perms), GFP_ATOMIC);
3415 if (!*perms)
3416 goto out;
3417
3418 if (match->comdatum) {
3419 rc = hashtab_map(&match->comdatum->permissions.table,
3420 get_permissions_callback, *perms);
3421 if (rc)
3422 goto err;
3423 }
3424
3425 rc = hashtab_map(&match->permissions.table, get_permissions_callback,
3426 *perms);
3427 if (rc)
3428 goto err;
3429
3430 out:
3431 return rc;
3432
3433 err:
3434 for (i = 0; i < *nperms; i++)
3435 kfree((*perms)[i]);
3436 kfree(*perms);
3437 return rc;
3438 }
3439
security_get_reject_unknown(void)3440 int security_get_reject_unknown(void)
3441 {
3442 struct selinux_policy *policy;
3443 int value;
3444
3445 if (!selinux_initialized())
3446 return 0;
3447
3448 rcu_read_lock();
3449 policy = rcu_dereference(selinux_state.policy);
3450 value = policy->policydb.reject_unknown;
3451 rcu_read_unlock();
3452 return value;
3453 }
3454
security_get_allow_unknown(void)3455 int security_get_allow_unknown(void)
3456 {
3457 struct selinux_policy *policy;
3458 int value;
3459
3460 if (!selinux_initialized())
3461 return 0;
3462
3463 rcu_read_lock();
3464 policy = rcu_dereference(selinux_state.policy);
3465 value = policy->policydb.allow_unknown;
3466 rcu_read_unlock();
3467 return value;
3468 }
3469
3470 /**
3471 * security_policycap_supported - Check for a specific policy capability
3472 * @req_cap: capability
3473 *
3474 * Description:
3475 * This function queries the currently loaded policy to see if it supports the
3476 * capability specified by @req_cap. Returns true (1) if the capability is
3477 * supported, false (0) if it isn't supported.
3478 *
3479 */
security_policycap_supported(unsigned int req_cap)3480 int security_policycap_supported(unsigned int req_cap)
3481 {
3482 struct selinux_policy *policy;
3483 int rc;
3484
3485 if (!selinux_initialized())
3486 return 0;
3487
3488 rcu_read_lock();
3489 policy = rcu_dereference(selinux_state.policy);
3490 rc = ebitmap_get_bit(&policy->policydb.policycaps, req_cap);
3491 rcu_read_unlock();
3492
3493 return rc;
3494 }
3495
3496 struct selinux_audit_rule {
3497 u32 au_seqno;
3498 struct context au_ctxt;
3499 };
3500
selinux_audit_rule_free(void * vrule)3501 void selinux_audit_rule_free(void *vrule)
3502 {
3503 struct selinux_audit_rule *rule = vrule;
3504
3505 if (rule) {
3506 context_destroy(&rule->au_ctxt);
3507 kfree(rule);
3508 }
3509 }
3510
selinux_audit_rule_init(u32 field,u32 op,char * rulestr,void ** vrule)3511 int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
3512 {
3513 struct selinux_state *state = &selinux_state;
3514 struct selinux_policy *policy;
3515 struct policydb *policydb;
3516 struct selinux_audit_rule *tmprule;
3517 struct role_datum *roledatum;
3518 struct type_datum *typedatum;
3519 struct user_datum *userdatum;
3520 struct selinux_audit_rule **rule = (struct selinux_audit_rule **)vrule;
3521 int rc = 0;
3522
3523 *rule = NULL;
3524
3525 if (!selinux_initialized())
3526 return -EOPNOTSUPP;
3527
3528 switch (field) {
3529 case AUDIT_SUBJ_USER:
3530 case AUDIT_SUBJ_ROLE:
3531 case AUDIT_SUBJ_TYPE:
3532 case AUDIT_OBJ_USER:
3533 case AUDIT_OBJ_ROLE:
3534 case AUDIT_OBJ_TYPE:
3535 /* only 'equals' and 'not equals' fit user, role, and type */
3536 if (op != Audit_equal && op != Audit_not_equal)
3537 return -EINVAL;
3538 break;
3539 case AUDIT_SUBJ_SEN:
3540 case AUDIT_SUBJ_CLR:
3541 case AUDIT_OBJ_LEV_LOW:
3542 case AUDIT_OBJ_LEV_HIGH:
3543 /* we do not allow a range, indicated by the presence of '-' */
3544 if (strchr(rulestr, '-'))
3545 return -EINVAL;
3546 break;
3547 default:
3548 /* only the above fields are valid */
3549 return -EINVAL;
3550 }
3551
3552 tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
3553 if (!tmprule)
3554 return -ENOMEM;
3555 context_init(&tmprule->au_ctxt);
3556
3557 rcu_read_lock();
3558 policy = rcu_dereference(state->policy);
3559 policydb = &policy->policydb;
3560 tmprule->au_seqno = policy->latest_granting;
3561 switch (field) {
3562 case AUDIT_SUBJ_USER:
3563 case AUDIT_OBJ_USER:
3564 userdatum = symtab_search(&policydb->p_users, rulestr);
3565 if (!userdatum) {
3566 rc = -EINVAL;
3567 goto err;
3568 }
3569 tmprule->au_ctxt.user = userdatum->value;
3570 break;
3571 case AUDIT_SUBJ_ROLE:
3572 case AUDIT_OBJ_ROLE:
3573 roledatum = symtab_search(&policydb->p_roles, rulestr);
3574 if (!roledatum) {
3575 rc = -EINVAL;
3576 goto err;
3577 }
3578 tmprule->au_ctxt.role = roledatum->value;
3579 break;
3580 case AUDIT_SUBJ_TYPE:
3581 case AUDIT_OBJ_TYPE:
3582 typedatum = symtab_search(&policydb->p_types, rulestr);
3583 if (!typedatum) {
3584 rc = -EINVAL;
3585 goto err;
3586 }
3587 tmprule->au_ctxt.type = typedatum->value;
3588 break;
3589 case AUDIT_SUBJ_SEN:
3590 case AUDIT_SUBJ_CLR:
3591 case AUDIT_OBJ_LEV_LOW:
3592 case AUDIT_OBJ_LEV_HIGH:
3593 rc = mls_from_string(policydb, rulestr, &tmprule->au_ctxt,
3594 GFP_ATOMIC);
3595 if (rc)
3596 goto err;
3597 break;
3598 }
3599 rcu_read_unlock();
3600
3601 *rule = tmprule;
3602 return 0;
3603
3604 err:
3605 rcu_read_unlock();
3606 selinux_audit_rule_free(tmprule);
3607 *rule = NULL;
3608 return rc;
3609 }
3610
3611 /* Check to see if the rule contains any selinux fields */
selinux_audit_rule_known(struct audit_krule * rule)3612 int selinux_audit_rule_known(struct audit_krule *rule)
3613 {
3614 u32 i;
3615
3616 for (i = 0; i < rule->field_count; i++) {
3617 struct audit_field *f = &rule->fields[i];
3618 switch (f->type) {
3619 case AUDIT_SUBJ_USER:
3620 case AUDIT_SUBJ_ROLE:
3621 case AUDIT_SUBJ_TYPE:
3622 case AUDIT_SUBJ_SEN:
3623 case AUDIT_SUBJ_CLR:
3624 case AUDIT_OBJ_USER:
3625 case AUDIT_OBJ_ROLE:
3626 case AUDIT_OBJ_TYPE:
3627 case AUDIT_OBJ_LEV_LOW:
3628 case AUDIT_OBJ_LEV_HIGH:
3629 return 1;
3630 }
3631 }
3632
3633 return 0;
3634 }
3635
selinux_audit_rule_match(u32 sid,u32 field,u32 op,void * vrule)3636 int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
3637 {
3638 struct selinux_state *state = &selinux_state;
3639 struct selinux_policy *policy;
3640 struct context *ctxt;
3641 struct mls_level *level;
3642 struct selinux_audit_rule *rule = vrule;
3643 int match = 0;
3644
3645 if (unlikely(!rule)) {
3646 WARN_ONCE(1, "selinux_audit_rule_match: missing rule\n");
3647 return -ENOENT;
3648 }
3649
3650 if (!selinux_initialized())
3651 return 0;
3652
3653 rcu_read_lock();
3654
3655 policy = rcu_dereference(state->policy);
3656
3657 if (rule->au_seqno < policy->latest_granting) {
3658 match = -ESTALE;
3659 goto out;
3660 }
3661
3662 ctxt = sidtab_search(policy->sidtab, sid);
3663 if (unlikely(!ctxt)) {
3664 WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
3665 sid);
3666 match = -ENOENT;
3667 goto out;
3668 }
3669
3670 /* a field/op pair that is not caught here will simply fall through
3671 without a match */
3672 switch (field) {
3673 case AUDIT_SUBJ_USER:
3674 case AUDIT_OBJ_USER:
3675 switch (op) {
3676 case Audit_equal:
3677 match = (ctxt->user == rule->au_ctxt.user);
3678 break;
3679 case Audit_not_equal:
3680 match = (ctxt->user != rule->au_ctxt.user);
3681 break;
3682 }
3683 break;
3684 case AUDIT_SUBJ_ROLE:
3685 case AUDIT_OBJ_ROLE:
3686 switch (op) {
3687 case Audit_equal:
3688 match = (ctxt->role == rule->au_ctxt.role);
3689 break;
3690 case Audit_not_equal:
3691 match = (ctxt->role != rule->au_ctxt.role);
3692 break;
3693 }
3694 break;
3695 case AUDIT_SUBJ_TYPE:
3696 case AUDIT_OBJ_TYPE:
3697 switch (op) {
3698 case Audit_equal:
3699 match = (ctxt->type == rule->au_ctxt.type);
3700 break;
3701 case Audit_not_equal:
3702 match = (ctxt->type != rule->au_ctxt.type);
3703 break;
3704 }
3705 break;
3706 case AUDIT_SUBJ_SEN:
3707 case AUDIT_SUBJ_CLR:
3708 case AUDIT_OBJ_LEV_LOW:
3709 case AUDIT_OBJ_LEV_HIGH:
3710 level = ((field == AUDIT_SUBJ_SEN ||
3711 field == AUDIT_OBJ_LEV_LOW) ?
3712 &ctxt->range.level[0] : &ctxt->range.level[1]);
3713 switch (op) {
3714 case Audit_equal:
3715 match = mls_level_eq(&rule->au_ctxt.range.level[0],
3716 level);
3717 break;
3718 case Audit_not_equal:
3719 match = !mls_level_eq(&rule->au_ctxt.range.level[0],
3720 level);
3721 break;
3722 case Audit_lt:
3723 match = (mls_level_dom(&rule->au_ctxt.range.level[0],
3724 level) &&
3725 !mls_level_eq(&rule->au_ctxt.range.level[0],
3726 level));
3727 break;
3728 case Audit_le:
3729 match = mls_level_dom(&rule->au_ctxt.range.level[0],
3730 level);
3731 break;
3732 case Audit_gt:
3733 match = (mls_level_dom(level,
3734 &rule->au_ctxt.range.level[0]) &&
3735 !mls_level_eq(level,
3736 &rule->au_ctxt.range.level[0]));
3737 break;
3738 case Audit_ge:
3739 match = mls_level_dom(level,
3740 &rule->au_ctxt.range.level[0]);
3741 break;
3742 }
3743 }
3744
3745 out:
3746 rcu_read_unlock();
3747 return match;
3748 }
3749
aurule_avc_callback(u32 event)3750 static int aurule_avc_callback(u32 event)
3751 {
3752 if (event == AVC_CALLBACK_RESET)
3753 return audit_update_lsm_rules();
3754 return 0;
3755 }
3756
aurule_init(void)3757 static int __init aurule_init(void)
3758 {
3759 int err;
3760
3761 err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET);
3762 if (err)
3763 panic("avc_add_callback() failed, error %d\n", err);
3764
3765 return err;
3766 }
3767 __initcall(aurule_init);
3768
3769 #ifdef CONFIG_NETLABEL
3770 /**
3771 * security_netlbl_cache_add - Add an entry to the NetLabel cache
3772 * @secattr: the NetLabel packet security attributes
3773 * @sid: the SELinux SID
3774 *
3775 * Description:
3776 * Attempt to cache the context in @ctx, which was derived from the packet in
3777 * @skb, in the NetLabel subsystem cache. This function assumes @secattr has
3778 * already been initialized.
3779 *
3780 */
security_netlbl_cache_add(struct netlbl_lsm_secattr * secattr,u32 sid)3781 static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
3782 u32 sid)
3783 {
3784 u32 *sid_cache;
3785
3786 sid_cache = kmalloc(sizeof(*sid_cache), GFP_ATOMIC);
3787 if (sid_cache == NULL)
3788 return;
3789 secattr->cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
3790 if (secattr->cache == NULL) {
3791 kfree(sid_cache);
3792 return;
3793 }
3794
3795 *sid_cache = sid;
3796 secattr->cache->free = kfree;
3797 secattr->cache->data = sid_cache;
3798 secattr->flags |= NETLBL_SECATTR_CACHE;
3799 }
3800
3801 /**
3802 * security_netlbl_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
3803 * @secattr: the NetLabel packet security attributes
3804 * @sid: the SELinux SID
3805 *
3806 * Description:
3807 * Convert the given NetLabel security attributes in @secattr into a
3808 * SELinux SID. If the @secattr field does not contain a full SELinux
3809 * SID/context then use SECINITSID_NETMSG as the foundation. If possible the
3810 * 'cache' field of @secattr is set and the CACHE flag is set; this is to
3811 * allow the @secattr to be used by NetLabel to cache the secattr to SID
3812 * conversion for future lookups. Returns zero on success, negative values on
3813 * failure.
3814 *
3815 */
security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr * secattr,u32 * sid)3816 int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
3817 u32 *sid)
3818 {
3819 struct selinux_policy *policy;
3820 struct policydb *policydb;
3821 struct sidtab *sidtab;
3822 int rc;
3823 struct context *ctx;
3824 struct context ctx_new;
3825
3826 if (!selinux_initialized()) {
3827 *sid = SECSID_NULL;
3828 return 0;
3829 }
3830
3831 retry:
3832 rc = 0;
3833 rcu_read_lock();
3834 policy = rcu_dereference(selinux_state.policy);
3835 policydb = &policy->policydb;
3836 sidtab = policy->sidtab;
3837
3838 if (secattr->flags & NETLBL_SECATTR_CACHE)
3839 *sid = *(u32 *)secattr->cache->data;
3840 else if (secattr->flags & NETLBL_SECATTR_SECID)
3841 *sid = secattr->attr.secid;
3842 else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
3843 rc = -EIDRM;
3844 ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
3845 if (ctx == NULL)
3846 goto out;
3847
3848 context_init(&ctx_new);
3849 ctx_new.user = ctx->user;
3850 ctx_new.role = ctx->role;
3851 ctx_new.type = ctx->type;
3852 mls_import_netlbl_lvl(policydb, &ctx_new, secattr);
3853 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
3854 rc = mls_import_netlbl_cat(policydb, &ctx_new, secattr);
3855 if (rc)
3856 goto out;
3857 }
3858 rc = -EIDRM;
3859 if (!mls_context_isvalid(policydb, &ctx_new)) {
3860 ebitmap_destroy(&ctx_new.range.level[0].cat);
3861 goto out;
3862 }
3863
3864 rc = sidtab_context_to_sid(sidtab, &ctx_new, sid);
3865 ebitmap_destroy(&ctx_new.range.level[0].cat);
3866 if (rc == -ESTALE) {
3867 rcu_read_unlock();
3868 goto retry;
3869 }
3870 if (rc)
3871 goto out;
3872
3873 security_netlbl_cache_add(secattr, *sid);
3874 } else
3875 *sid = SECSID_NULL;
3876
3877 out:
3878 rcu_read_unlock();
3879 return rc;
3880 }
3881
3882 /**
3883 * security_netlbl_sid_to_secattr - Convert a SELinux SID to a NetLabel secattr
3884 * @sid: the SELinux SID
3885 * @secattr: the NetLabel packet security attributes
3886 *
3887 * Description:
3888 * Convert the given SELinux SID in @sid into a NetLabel security attribute.
3889 * Returns zero on success, negative values on failure.
3890 *
3891 */
security_netlbl_sid_to_secattr(u32 sid,struct netlbl_lsm_secattr * secattr)3892 int security_netlbl_sid_to_secattr(u32 sid, struct netlbl_lsm_secattr *secattr)
3893 {
3894 struct selinux_policy *policy;
3895 struct policydb *policydb;
3896 int rc;
3897 struct context *ctx;
3898
3899 if (!selinux_initialized())
3900 return 0;
3901
3902 rcu_read_lock();
3903 policy = rcu_dereference(selinux_state.policy);
3904 policydb = &policy->policydb;
3905
3906 rc = -ENOENT;
3907 ctx = sidtab_search(policy->sidtab, sid);
3908 if (ctx == NULL)
3909 goto out;
3910
3911 rc = -ENOMEM;
3912 secattr->domain = kstrdup(sym_name(policydb, SYM_TYPES, ctx->type - 1),
3913 GFP_ATOMIC);
3914 if (secattr->domain == NULL)
3915 goto out;
3916
3917 secattr->attr.secid = sid;
3918 secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
3919 mls_export_netlbl_lvl(policydb, ctx, secattr);
3920 rc = mls_export_netlbl_cat(policydb, ctx, secattr);
3921 out:
3922 rcu_read_unlock();
3923 return rc;
3924 }
3925 #endif /* CONFIG_NETLABEL */
3926
3927 /**
3928 * __security_read_policy - read the policy.
3929 * @policy: SELinux policy
3930 * @data: binary policy data
3931 * @len: length of data in bytes
3932 *
3933 */
__security_read_policy(struct selinux_policy * policy,void * data,size_t * len)3934 static int __security_read_policy(struct selinux_policy *policy,
3935 void *data, size_t *len)
3936 {
3937 int rc;
3938 struct policy_file fp;
3939
3940 fp.data = data;
3941 fp.len = *len;
3942
3943 rc = policydb_write(&policy->policydb, &fp);
3944 if (rc)
3945 return rc;
3946
3947 *len = (unsigned long)fp.data - (unsigned long)data;
3948 return 0;
3949 }
3950
3951 /**
3952 * security_read_policy - read the policy.
3953 * @data: binary policy data
3954 * @len: length of data in bytes
3955 *
3956 */
security_read_policy(void ** data,size_t * len)3957 int security_read_policy(void **data, size_t *len)
3958 {
3959 struct selinux_state *state = &selinux_state;
3960 struct selinux_policy *policy;
3961
3962 policy = rcu_dereference_protected(
3963 state->policy, lockdep_is_held(&state->policy_mutex));
3964 if (!policy)
3965 return -EINVAL;
3966
3967 *len = policy->policydb.len;
3968 *data = vmalloc_user(*len);
3969 if (!*data)
3970 return -ENOMEM;
3971
3972 return __security_read_policy(policy, *data, len);
3973 }
3974
3975 /**
3976 * security_read_state_kernel - read the policy.
3977 * @data: binary policy data
3978 * @len: length of data in bytes
3979 *
3980 * Allocates kernel memory for reading SELinux policy.
3981 * This function is for internal use only and should not
3982 * be used for returning data to user space.
3983 *
3984 * This function must be called with policy_mutex held.
3985 */
security_read_state_kernel(void ** data,size_t * len)3986 int security_read_state_kernel(void **data, size_t *len)
3987 {
3988 int err;
3989 struct selinux_state *state = &selinux_state;
3990 struct selinux_policy *policy;
3991
3992 policy = rcu_dereference_protected(
3993 state->policy, lockdep_is_held(&state->policy_mutex));
3994 if (!policy)
3995 return -EINVAL;
3996
3997 *len = policy->policydb.len;
3998 *data = vmalloc(*len);
3999 if (!*data)
4000 return -ENOMEM;
4001
4002 err = __security_read_policy(policy, *data, len);
4003 if (err) {
4004 vfree(*data);
4005 *data = NULL;
4006 *len = 0;
4007 }
4008 return err;
4009 }
4010