1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Implementation of the security services.
4 *
5 * Authors : Stephen Smalley, <sds@tycho.nsa.gov>
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 convert_context_args {
72 struct selinux_state *state;
73 struct policydb *oldp;
74 struct policydb *newp;
75 };
76
77 struct selinux_policy_convert_data {
78 struct convert_context_args args;
79 struct sidtab_convert_params sidtab_params;
80 };
81
82 /* Forward declaration. */
83 static int context_struct_to_string(struct policydb *policydb,
84 struct context *context,
85 char **scontext,
86 u32 *scontext_len);
87
88 static int sidtab_entry_to_string(struct policydb *policydb,
89 struct sidtab *sidtab,
90 struct sidtab_entry *entry,
91 char **scontext,
92 u32 *scontext_len);
93
94 static void context_struct_compute_av(struct policydb *policydb,
95 struct context *scontext,
96 struct context *tcontext,
97 u16 tclass,
98 struct av_decision *avd,
99 struct extended_perms *xperms);
100
selinux_set_mapping(struct policydb * pol,struct security_class_mapping * map,struct selinux_map * out_map)101 static int selinux_set_mapping(struct policydb *pol,
102 struct security_class_mapping *map,
103 struct selinux_map *out_map)
104 {
105 u16 i, j;
106 unsigned k;
107 bool print_unknown_handle = false;
108
109 /* Find number of classes in the input mapping */
110 if (!map)
111 return -EINVAL;
112 i = 0;
113 while (map[i].name)
114 i++;
115
116 /* Allocate space for the class records, plus one for class zero */
117 out_map->mapping = kcalloc(++i, sizeof(*out_map->mapping), GFP_ATOMIC);
118 if (!out_map->mapping)
119 return -ENOMEM;
120
121 /* Store the raw class and permission values */
122 j = 0;
123 while (map[j].name) {
124 struct security_class_mapping *p_in = map + (j++);
125 struct selinux_mapping *p_out = out_map->mapping + j;
126
127 /* An empty class string skips ahead */
128 if (!strcmp(p_in->name, "")) {
129 p_out->num_perms = 0;
130 continue;
131 }
132
133 p_out->value = string_to_security_class(pol, p_in->name);
134 if (!p_out->value) {
135 pr_info("SELinux: Class %s not defined in policy.\n",
136 p_in->name);
137 if (pol->reject_unknown)
138 goto err;
139 p_out->num_perms = 0;
140 print_unknown_handle = true;
141 continue;
142 }
143
144 k = 0;
145 while (p_in->perms[k]) {
146 /* An empty permission string skips ahead */
147 if (!*p_in->perms[k]) {
148 k++;
149 continue;
150 }
151 p_out->perms[k] = string_to_av_perm(pol, p_out->value,
152 p_in->perms[k]);
153 if (!p_out->perms[k]) {
154 pr_info("SELinux: Permission %s in class %s not defined in policy.\n",
155 p_in->perms[k], p_in->name);
156 if (pol->reject_unknown)
157 goto err;
158 print_unknown_handle = true;
159 }
160
161 k++;
162 }
163 p_out->num_perms = k;
164 }
165
166 if (print_unknown_handle)
167 pr_info("SELinux: the above unknown classes and permissions will be %s\n",
168 pol->allow_unknown ? "allowed" : "denied");
169
170 out_map->size = i;
171 return 0;
172 err:
173 kfree(out_map->mapping);
174 out_map->mapping = NULL;
175 return -EINVAL;
176 }
177
178 /*
179 * Get real, policy values from mapped values
180 */
181
unmap_class(struct selinux_map * map,u16 tclass)182 static u16 unmap_class(struct selinux_map *map, u16 tclass)
183 {
184 if (tclass < map->size)
185 return map->mapping[tclass].value;
186
187 return tclass;
188 }
189
190 /*
191 * Get kernel value for class from its policy value
192 */
map_class(struct selinux_map * map,u16 pol_value)193 static u16 map_class(struct selinux_map *map, u16 pol_value)
194 {
195 u16 i;
196
197 for (i = 1; i < map->size; i++) {
198 if (map->mapping[i].value == pol_value)
199 return i;
200 }
201
202 return SECCLASS_NULL;
203 }
204
map_decision(struct selinux_map * map,u16 tclass,struct av_decision * avd,int allow_unknown)205 static void map_decision(struct selinux_map *map,
206 u16 tclass, struct av_decision *avd,
207 int allow_unknown)
208 {
209 if (tclass < map->size) {
210 struct selinux_mapping *mapping = &map->mapping[tclass];
211 unsigned int i, n = mapping->num_perms;
212 u32 result;
213
214 for (i = 0, result = 0; i < n; i++) {
215 if (avd->allowed & mapping->perms[i])
216 result |= 1<<i;
217 if (allow_unknown && !mapping->perms[i])
218 result |= 1<<i;
219 }
220 avd->allowed = result;
221
222 for (i = 0, result = 0; i < n; i++)
223 if (avd->auditallow & mapping->perms[i])
224 result |= 1<<i;
225 avd->auditallow = result;
226
227 for (i = 0, result = 0; i < n; i++) {
228 if (avd->auditdeny & mapping->perms[i])
229 result |= 1<<i;
230 if (!allow_unknown && !mapping->perms[i])
231 result |= 1<<i;
232 }
233 /*
234 * In case the kernel has a bug and requests a permission
235 * between num_perms and the maximum permission number, we
236 * should audit that denial
237 */
238 for (; i < (sizeof(u32)*8); i++)
239 result |= 1<<i;
240 avd->auditdeny = result;
241 }
242 }
243
security_mls_enabled(struct selinux_state * state)244 int security_mls_enabled(struct selinux_state *state)
245 {
246 int mls_enabled;
247 struct selinux_policy *policy;
248
249 if (!selinux_initialized(state))
250 return 0;
251
252 rcu_read_lock();
253 policy = rcu_dereference(state->policy);
254 mls_enabled = policy->policydb.mls_enabled;
255 rcu_read_unlock();
256 return mls_enabled;
257 }
258
259 /*
260 * Return the boolean value of a constraint expression
261 * when it is applied to the specified source and target
262 * security contexts.
263 *
264 * xcontext is a special beast... It is used by the validatetrans rules
265 * only. For these rules, scontext is the context before the transition,
266 * tcontext is the context after the transition, and xcontext is the context
267 * of the process performing the transition. All other callers of
268 * constraint_expr_eval should pass in NULL for xcontext.
269 */
constraint_expr_eval(struct policydb * policydb,struct context * scontext,struct context * tcontext,struct context * xcontext,struct constraint_expr * cexpr)270 static int constraint_expr_eval(struct policydb *policydb,
271 struct context *scontext,
272 struct context *tcontext,
273 struct context *xcontext,
274 struct constraint_expr *cexpr)
275 {
276 u32 val1, val2;
277 struct context *c;
278 struct role_datum *r1, *r2;
279 struct mls_level *l1, *l2;
280 struct constraint_expr *e;
281 int s[CEXPR_MAXDEPTH];
282 int sp = -1;
283
284 for (e = cexpr; e; e = e->next) {
285 switch (e->expr_type) {
286 case CEXPR_NOT:
287 BUG_ON(sp < 0);
288 s[sp] = !s[sp];
289 break;
290 case CEXPR_AND:
291 BUG_ON(sp < 1);
292 sp--;
293 s[sp] &= s[sp + 1];
294 break;
295 case CEXPR_OR:
296 BUG_ON(sp < 1);
297 sp--;
298 s[sp] |= s[sp + 1];
299 break;
300 case CEXPR_ATTR:
301 if (sp == (CEXPR_MAXDEPTH - 1))
302 return 0;
303 switch (e->attr) {
304 case CEXPR_USER:
305 val1 = scontext->user;
306 val2 = tcontext->user;
307 break;
308 case CEXPR_TYPE:
309 val1 = scontext->type;
310 val2 = tcontext->type;
311 break;
312 case CEXPR_ROLE:
313 val1 = scontext->role;
314 val2 = tcontext->role;
315 r1 = policydb->role_val_to_struct[val1 - 1];
316 r2 = policydb->role_val_to_struct[val2 - 1];
317 switch (e->op) {
318 case CEXPR_DOM:
319 s[++sp] = ebitmap_get_bit(&r1->dominates,
320 val2 - 1);
321 continue;
322 case CEXPR_DOMBY:
323 s[++sp] = ebitmap_get_bit(&r2->dominates,
324 val1 - 1);
325 continue;
326 case CEXPR_INCOMP:
327 s[++sp] = (!ebitmap_get_bit(&r1->dominates,
328 val2 - 1) &&
329 !ebitmap_get_bit(&r2->dominates,
330 val1 - 1));
331 continue;
332 default:
333 break;
334 }
335 break;
336 case CEXPR_L1L2:
337 l1 = &(scontext->range.level[0]);
338 l2 = &(tcontext->range.level[0]);
339 goto mls_ops;
340 case CEXPR_L1H2:
341 l1 = &(scontext->range.level[0]);
342 l2 = &(tcontext->range.level[1]);
343 goto mls_ops;
344 case CEXPR_H1L2:
345 l1 = &(scontext->range.level[1]);
346 l2 = &(tcontext->range.level[0]);
347 goto mls_ops;
348 case CEXPR_H1H2:
349 l1 = &(scontext->range.level[1]);
350 l2 = &(tcontext->range.level[1]);
351 goto mls_ops;
352 case CEXPR_L1H1:
353 l1 = &(scontext->range.level[0]);
354 l2 = &(scontext->range.level[1]);
355 goto mls_ops;
356 case CEXPR_L2H2:
357 l1 = &(tcontext->range.level[0]);
358 l2 = &(tcontext->range.level[1]);
359 goto mls_ops;
360 mls_ops:
361 switch (e->op) {
362 case CEXPR_EQ:
363 s[++sp] = mls_level_eq(l1, l2);
364 continue;
365 case CEXPR_NEQ:
366 s[++sp] = !mls_level_eq(l1, l2);
367 continue;
368 case CEXPR_DOM:
369 s[++sp] = mls_level_dom(l1, l2);
370 continue;
371 case CEXPR_DOMBY:
372 s[++sp] = mls_level_dom(l2, l1);
373 continue;
374 case CEXPR_INCOMP:
375 s[++sp] = mls_level_incomp(l2, l1);
376 continue;
377 default:
378 BUG();
379 return 0;
380 }
381 break;
382 default:
383 BUG();
384 return 0;
385 }
386
387 switch (e->op) {
388 case CEXPR_EQ:
389 s[++sp] = (val1 == val2);
390 break;
391 case CEXPR_NEQ:
392 s[++sp] = (val1 != val2);
393 break;
394 default:
395 BUG();
396 return 0;
397 }
398 break;
399 case CEXPR_NAMES:
400 if (sp == (CEXPR_MAXDEPTH-1))
401 return 0;
402 c = scontext;
403 if (e->attr & CEXPR_TARGET)
404 c = tcontext;
405 else if (e->attr & CEXPR_XTARGET) {
406 c = xcontext;
407 if (!c) {
408 BUG();
409 return 0;
410 }
411 }
412 if (e->attr & CEXPR_USER)
413 val1 = c->user;
414 else if (e->attr & CEXPR_ROLE)
415 val1 = c->role;
416 else if (e->attr & CEXPR_TYPE)
417 val1 = c->type;
418 else {
419 BUG();
420 return 0;
421 }
422
423 switch (e->op) {
424 case CEXPR_EQ:
425 s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
426 break;
427 case CEXPR_NEQ:
428 s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
429 break;
430 default:
431 BUG();
432 return 0;
433 }
434 break;
435 default:
436 BUG();
437 return 0;
438 }
439 }
440
441 BUG_ON(sp != 0);
442 return s[0];
443 }
444
445 /*
446 * security_dump_masked_av - dumps masked permissions during
447 * security_compute_av due to RBAC, MLS/Constraint and Type bounds.
448 */
dump_masked_av_helper(void * k,void * d,void * args)449 static int dump_masked_av_helper(void *k, void *d, void *args)
450 {
451 struct perm_datum *pdatum = d;
452 char **permission_names = args;
453
454 BUG_ON(pdatum->value < 1 || pdatum->value > 32);
455
456 permission_names[pdatum->value - 1] = (char *)k;
457
458 return 0;
459 }
460
security_dump_masked_av(struct policydb * policydb,struct context * scontext,struct context * tcontext,u16 tclass,u32 permissions,const char * reason)461 static void security_dump_masked_av(struct policydb *policydb,
462 struct context *scontext,
463 struct context *tcontext,
464 u16 tclass,
465 u32 permissions,
466 const char *reason)
467 {
468 struct common_datum *common_dat;
469 struct class_datum *tclass_dat;
470 struct audit_buffer *ab;
471 char *tclass_name;
472 char *scontext_name = NULL;
473 char *tcontext_name = NULL;
474 char *permission_names[32];
475 int index;
476 u32 length;
477 bool need_comma = false;
478
479 if (!permissions)
480 return;
481
482 tclass_name = sym_name(policydb, SYM_CLASSES, tclass - 1);
483 tclass_dat = policydb->class_val_to_struct[tclass - 1];
484 common_dat = tclass_dat->comdatum;
485
486 /* init permission_names */
487 if (common_dat &&
488 hashtab_map(&common_dat->permissions.table,
489 dump_masked_av_helper, permission_names) < 0)
490 goto out;
491
492 if (hashtab_map(&tclass_dat->permissions.table,
493 dump_masked_av_helper, permission_names) < 0)
494 goto out;
495
496 /* get scontext/tcontext in text form */
497 if (context_struct_to_string(policydb, scontext,
498 &scontext_name, &length) < 0)
499 goto out;
500
501 if (context_struct_to_string(policydb, tcontext,
502 &tcontext_name, &length) < 0)
503 goto out;
504
505 /* audit a message */
506 ab = audit_log_start(audit_context(),
507 GFP_ATOMIC, AUDIT_SELINUX_ERR);
508 if (!ab)
509 goto out;
510
511 audit_log_format(ab, "op=security_compute_av reason=%s "
512 "scontext=%s tcontext=%s tclass=%s perms=",
513 reason, scontext_name, tcontext_name, tclass_name);
514
515 for (index = 0; index < 32; index++) {
516 u32 mask = (1 << index);
517
518 if ((mask & permissions) == 0)
519 continue;
520
521 audit_log_format(ab, "%s%s",
522 need_comma ? "," : "",
523 permission_names[index]
524 ? permission_names[index] : "????");
525 need_comma = true;
526 }
527 audit_log_end(ab);
528 out:
529 /* release scontext/tcontext */
530 kfree(tcontext_name);
531 kfree(scontext_name);
532
533 return;
534 }
535
536 /*
537 * security_boundary_permission - drops violated permissions
538 * on boundary constraint.
539 */
type_attribute_bounds_av(struct policydb * policydb,struct context * scontext,struct context * tcontext,u16 tclass,struct av_decision * avd)540 static void type_attribute_bounds_av(struct policydb *policydb,
541 struct context *scontext,
542 struct context *tcontext,
543 u16 tclass,
544 struct av_decision *avd)
545 {
546 struct context lo_scontext;
547 struct context lo_tcontext, *tcontextp = tcontext;
548 struct av_decision lo_avd;
549 struct type_datum *source;
550 struct type_datum *target;
551 u32 masked = 0;
552
553 source = policydb->type_val_to_struct[scontext->type - 1];
554 BUG_ON(!source);
555
556 if (!source->bounds)
557 return;
558
559 target = policydb->type_val_to_struct[tcontext->type - 1];
560 BUG_ON(!target);
561
562 memset(&lo_avd, 0, sizeof(lo_avd));
563
564 memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
565 lo_scontext.type = source->bounds;
566
567 if (target->bounds) {
568 memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
569 lo_tcontext.type = target->bounds;
570 tcontextp = &lo_tcontext;
571 }
572
573 context_struct_compute_av(policydb, &lo_scontext,
574 tcontextp,
575 tclass,
576 &lo_avd,
577 NULL);
578
579 masked = ~lo_avd.allowed & avd->allowed;
580
581 if (likely(!masked))
582 return; /* no masked permission */
583
584 /* mask violated permissions */
585 avd->allowed &= ~masked;
586
587 /* audit masked permissions */
588 security_dump_masked_av(policydb, scontext, tcontext,
589 tclass, masked, "bounds");
590 }
591
592 /*
593 * flag which drivers have permissions
594 * only looking for ioctl based extended permssions
595 */
services_compute_xperms_drivers(struct extended_perms * xperms,struct avtab_node * node)596 void services_compute_xperms_drivers(
597 struct extended_perms *xperms,
598 struct avtab_node *node)
599 {
600 unsigned int i;
601
602 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
603 /* if one or more driver has all permissions allowed */
604 for (i = 0; i < ARRAY_SIZE(xperms->drivers.p); i++)
605 xperms->drivers.p[i] |= node->datum.u.xperms->perms.p[i];
606 } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
607 /* if allowing permissions within a driver */
608 security_xperm_set(xperms->drivers.p,
609 node->datum.u.xperms->driver);
610 }
611
612 xperms->len = 1;
613 }
614
615 /*
616 * Compute access vectors and extended permissions based on a context
617 * structure pair for the permissions in a particular class.
618 */
context_struct_compute_av(struct policydb * policydb,struct context * scontext,struct context * tcontext,u16 tclass,struct av_decision * avd,struct extended_perms * xperms)619 static void context_struct_compute_av(struct policydb *policydb,
620 struct context *scontext,
621 struct context *tcontext,
622 u16 tclass,
623 struct av_decision *avd,
624 struct extended_perms *xperms)
625 {
626 struct constraint_node *constraint;
627 struct role_allow *ra;
628 struct avtab_key avkey;
629 struct avtab_node *node;
630 struct class_datum *tclass_datum;
631 struct ebitmap *sattr, *tattr;
632 struct ebitmap_node *snode, *tnode;
633 unsigned int i, j;
634
635 avd->allowed = 0;
636 avd->auditallow = 0;
637 avd->auditdeny = 0xffffffff;
638 if (xperms) {
639 memset(&xperms->drivers, 0, sizeof(xperms->drivers));
640 xperms->len = 0;
641 }
642
643 if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
644 if (printk_ratelimit())
645 pr_warn("SELinux: Invalid class %hu\n", tclass);
646 return;
647 }
648
649 tclass_datum = policydb->class_val_to_struct[tclass - 1];
650
651 /*
652 * If a specific type enforcement rule was defined for
653 * this permission check, then use it.
654 */
655 avkey.target_class = tclass;
656 avkey.specified = AVTAB_AV | AVTAB_XPERMS;
657 sattr = &policydb->type_attr_map_array[scontext->type - 1];
658 tattr = &policydb->type_attr_map_array[tcontext->type - 1];
659 ebitmap_for_each_positive_bit(sattr, snode, i) {
660 ebitmap_for_each_positive_bit(tattr, tnode, j) {
661 avkey.source_type = i + 1;
662 avkey.target_type = j + 1;
663 for (node = avtab_search_node(&policydb->te_avtab,
664 &avkey);
665 node;
666 node = avtab_search_node_next(node, avkey.specified)) {
667 if (node->key.specified == AVTAB_ALLOWED)
668 avd->allowed |= node->datum.u.data;
669 else if (node->key.specified == AVTAB_AUDITALLOW)
670 avd->auditallow |= node->datum.u.data;
671 else if (node->key.specified == AVTAB_AUDITDENY)
672 avd->auditdeny &= node->datum.u.data;
673 else if (xperms && (node->key.specified & AVTAB_XPERMS))
674 services_compute_xperms_drivers(xperms, node);
675 }
676
677 /* Check conditional av table for additional permissions */
678 cond_compute_av(&policydb->te_cond_avtab, &avkey,
679 avd, xperms);
680
681 }
682 }
683
684 /*
685 * Remove any permissions prohibited by a constraint (this includes
686 * the MLS policy).
687 */
688 constraint = tclass_datum->constraints;
689 while (constraint) {
690 if ((constraint->permissions & (avd->allowed)) &&
691 !constraint_expr_eval(policydb, scontext, tcontext, NULL,
692 constraint->expr)) {
693 avd->allowed &= ~(constraint->permissions);
694 }
695 constraint = constraint->next;
696 }
697
698 /*
699 * If checking process transition permission and the
700 * role is changing, then check the (current_role, new_role)
701 * pair.
702 */
703 if (tclass == policydb->process_class &&
704 (avd->allowed & policydb->process_trans_perms) &&
705 scontext->role != tcontext->role) {
706 for (ra = policydb->role_allow; ra; ra = ra->next) {
707 if (scontext->role == ra->role &&
708 tcontext->role == ra->new_role)
709 break;
710 }
711 if (!ra)
712 avd->allowed &= ~policydb->process_trans_perms;
713 }
714
715 /*
716 * If the given source and target types have boundary
717 * constraint, lazy checks have to mask any violated
718 * permission and notice it to userspace via audit.
719 */
720 type_attribute_bounds_av(policydb, scontext, tcontext,
721 tclass, avd);
722 }
723
security_validtrans_handle_fail(struct selinux_state * state,struct selinux_policy * policy,struct sidtab_entry * oentry,struct sidtab_entry * nentry,struct sidtab_entry * tentry,u16 tclass)724 static int security_validtrans_handle_fail(struct selinux_state *state,
725 struct selinux_policy *policy,
726 struct sidtab_entry *oentry,
727 struct sidtab_entry *nentry,
728 struct sidtab_entry *tentry,
729 u16 tclass)
730 {
731 struct policydb *p = &policy->policydb;
732 struct sidtab *sidtab = policy->sidtab;
733 char *o = NULL, *n = NULL, *t = NULL;
734 u32 olen, nlen, tlen;
735
736 if (sidtab_entry_to_string(p, sidtab, oentry, &o, &olen))
737 goto out;
738 if (sidtab_entry_to_string(p, sidtab, nentry, &n, &nlen))
739 goto out;
740 if (sidtab_entry_to_string(p, sidtab, tentry, &t, &tlen))
741 goto out;
742 audit_log(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR,
743 "op=security_validate_transition seresult=denied"
744 " oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
745 o, n, t, sym_name(p, SYM_CLASSES, tclass-1));
746 out:
747 kfree(o);
748 kfree(n);
749 kfree(t);
750
751 if (!enforcing_enabled(state))
752 return 0;
753 return -EPERM;
754 }
755
security_compute_validatetrans(struct selinux_state * state,u32 oldsid,u32 newsid,u32 tasksid,u16 orig_tclass,bool user)756 static int security_compute_validatetrans(struct selinux_state *state,
757 u32 oldsid, u32 newsid, u32 tasksid,
758 u16 orig_tclass, bool user)
759 {
760 struct selinux_policy *policy;
761 struct policydb *policydb;
762 struct sidtab *sidtab;
763 struct sidtab_entry *oentry;
764 struct sidtab_entry *nentry;
765 struct sidtab_entry *tentry;
766 struct class_datum *tclass_datum;
767 struct constraint_node *constraint;
768 u16 tclass;
769 int rc = 0;
770
771
772 if (!selinux_initialized(state))
773 return 0;
774
775 rcu_read_lock();
776
777 policy = rcu_dereference(state->policy);
778 policydb = &policy->policydb;
779 sidtab = policy->sidtab;
780
781 if (!user)
782 tclass = unmap_class(&policy->map, orig_tclass);
783 else
784 tclass = orig_tclass;
785
786 if (!tclass || tclass > policydb->p_classes.nprim) {
787 rc = -EINVAL;
788 goto out;
789 }
790 tclass_datum = policydb->class_val_to_struct[tclass - 1];
791
792 oentry = sidtab_search_entry(sidtab, oldsid);
793 if (!oentry) {
794 pr_err("SELinux: %s: unrecognized SID %d\n",
795 __func__, oldsid);
796 rc = -EINVAL;
797 goto out;
798 }
799
800 nentry = sidtab_search_entry(sidtab, newsid);
801 if (!nentry) {
802 pr_err("SELinux: %s: unrecognized SID %d\n",
803 __func__, newsid);
804 rc = -EINVAL;
805 goto out;
806 }
807
808 tentry = sidtab_search_entry(sidtab, tasksid);
809 if (!tentry) {
810 pr_err("SELinux: %s: unrecognized SID %d\n",
811 __func__, tasksid);
812 rc = -EINVAL;
813 goto out;
814 }
815
816 constraint = tclass_datum->validatetrans;
817 while (constraint) {
818 if (!constraint_expr_eval(policydb, &oentry->context,
819 &nentry->context, &tentry->context,
820 constraint->expr)) {
821 if (user)
822 rc = -EPERM;
823 else
824 rc = security_validtrans_handle_fail(state,
825 policy,
826 oentry,
827 nentry,
828 tentry,
829 tclass);
830 goto out;
831 }
832 constraint = constraint->next;
833 }
834
835 out:
836 rcu_read_unlock();
837 return rc;
838 }
839
security_validate_transition_user(struct selinux_state * state,u32 oldsid,u32 newsid,u32 tasksid,u16 tclass)840 int security_validate_transition_user(struct selinux_state *state,
841 u32 oldsid, u32 newsid, u32 tasksid,
842 u16 tclass)
843 {
844 return security_compute_validatetrans(state, oldsid, newsid, tasksid,
845 tclass, true);
846 }
847
security_validate_transition(struct selinux_state * state,u32 oldsid,u32 newsid,u32 tasksid,u16 orig_tclass)848 int security_validate_transition(struct selinux_state *state,
849 u32 oldsid, u32 newsid, u32 tasksid,
850 u16 orig_tclass)
851 {
852 return security_compute_validatetrans(state, oldsid, newsid, tasksid,
853 orig_tclass, false);
854 }
855
856 /*
857 * security_bounded_transition - check whether the given
858 * transition is directed to bounded, or not.
859 * It returns 0, if @newsid is bounded by @oldsid.
860 * Otherwise, it returns error code.
861 *
862 * @state: SELinux state
863 * @oldsid : current security identifier
864 * @newsid : destinated security identifier
865 */
security_bounded_transition(struct selinux_state * state,u32 old_sid,u32 new_sid)866 int security_bounded_transition(struct selinux_state *state,
867 u32 old_sid, u32 new_sid)
868 {
869 struct selinux_policy *policy;
870 struct policydb *policydb;
871 struct sidtab *sidtab;
872 struct sidtab_entry *old_entry, *new_entry;
873 struct type_datum *type;
874 int index;
875 int rc;
876
877 if (!selinux_initialized(state))
878 return 0;
879
880 rcu_read_lock();
881 policy = rcu_dereference(state->policy);
882 policydb = &policy->policydb;
883 sidtab = policy->sidtab;
884
885 rc = -EINVAL;
886 old_entry = sidtab_search_entry(sidtab, old_sid);
887 if (!old_entry) {
888 pr_err("SELinux: %s: unrecognized SID %u\n",
889 __func__, old_sid);
890 goto out;
891 }
892
893 rc = -EINVAL;
894 new_entry = sidtab_search_entry(sidtab, new_sid);
895 if (!new_entry) {
896 pr_err("SELinux: %s: unrecognized SID %u\n",
897 __func__, new_sid);
898 goto out;
899 }
900
901 rc = 0;
902 /* type/domain unchanged */
903 if (old_entry->context.type == new_entry->context.type)
904 goto out;
905
906 index = new_entry->context.type;
907 while (true) {
908 type = policydb->type_val_to_struct[index - 1];
909 BUG_ON(!type);
910
911 /* not bounded anymore */
912 rc = -EPERM;
913 if (!type->bounds)
914 break;
915
916 /* @newsid is bounded by @oldsid */
917 rc = 0;
918 if (type->bounds == old_entry->context.type)
919 break;
920
921 index = type->bounds;
922 }
923
924 if (rc) {
925 char *old_name = NULL;
926 char *new_name = NULL;
927 u32 length;
928
929 if (!sidtab_entry_to_string(policydb, sidtab, old_entry,
930 &old_name, &length) &&
931 !sidtab_entry_to_string(policydb, sidtab, new_entry,
932 &new_name, &length)) {
933 audit_log(audit_context(),
934 GFP_ATOMIC, AUDIT_SELINUX_ERR,
935 "op=security_bounded_transition "
936 "seresult=denied "
937 "oldcontext=%s newcontext=%s",
938 old_name, new_name);
939 }
940 kfree(new_name);
941 kfree(old_name);
942 }
943 out:
944 rcu_read_unlock();
945
946 return rc;
947 }
948
avd_init(struct selinux_policy * policy,struct av_decision * avd)949 static void avd_init(struct selinux_policy *policy, struct av_decision *avd)
950 {
951 avd->allowed = 0;
952 avd->auditallow = 0;
953 avd->auditdeny = 0xffffffff;
954 if (policy)
955 avd->seqno = policy->latest_granting;
956 else
957 avd->seqno = 0;
958 avd->flags = 0;
959 }
960
services_compute_xperms_decision(struct extended_perms_decision * xpermd,struct avtab_node * node)961 void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
962 struct avtab_node *node)
963 {
964 unsigned int i;
965
966 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
967 if (xpermd->driver != node->datum.u.xperms->driver)
968 return;
969 } else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
970 if (!security_xperm_test(node->datum.u.xperms->perms.p,
971 xpermd->driver))
972 return;
973 } else {
974 BUG();
975 }
976
977 if (node->key.specified == AVTAB_XPERMS_ALLOWED) {
978 xpermd->used |= XPERMS_ALLOWED;
979 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
980 memset(xpermd->allowed->p, 0xff,
981 sizeof(xpermd->allowed->p));
982 }
983 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
984 for (i = 0; i < ARRAY_SIZE(xpermd->allowed->p); i++)
985 xpermd->allowed->p[i] |=
986 node->datum.u.xperms->perms.p[i];
987 }
988 } else if (node->key.specified == AVTAB_XPERMS_AUDITALLOW) {
989 xpermd->used |= XPERMS_AUDITALLOW;
990 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
991 memset(xpermd->auditallow->p, 0xff,
992 sizeof(xpermd->auditallow->p));
993 }
994 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
995 for (i = 0; i < ARRAY_SIZE(xpermd->auditallow->p); i++)
996 xpermd->auditallow->p[i] |=
997 node->datum.u.xperms->perms.p[i];
998 }
999 } else if (node->key.specified == AVTAB_XPERMS_DONTAUDIT) {
1000 xpermd->used |= XPERMS_DONTAUDIT;
1001 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
1002 memset(xpermd->dontaudit->p, 0xff,
1003 sizeof(xpermd->dontaudit->p));
1004 }
1005 if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
1006 for (i = 0; i < ARRAY_SIZE(xpermd->dontaudit->p); i++)
1007 xpermd->dontaudit->p[i] |=
1008 node->datum.u.xperms->perms.p[i];
1009 }
1010 } else {
1011 BUG();
1012 }
1013 }
1014
security_compute_xperms_decision(struct selinux_state * state,u32 ssid,u32 tsid,u16 orig_tclass,u8 driver,struct extended_perms_decision * xpermd)1015 void security_compute_xperms_decision(struct selinux_state *state,
1016 u32 ssid,
1017 u32 tsid,
1018 u16 orig_tclass,
1019 u8 driver,
1020 struct extended_perms_decision *xpermd)
1021 {
1022 struct selinux_policy *policy;
1023 struct policydb *policydb;
1024 struct sidtab *sidtab;
1025 u16 tclass;
1026 struct context *scontext, *tcontext;
1027 struct avtab_key avkey;
1028 struct avtab_node *node;
1029 struct ebitmap *sattr, *tattr;
1030 struct ebitmap_node *snode, *tnode;
1031 unsigned int i, j;
1032
1033 xpermd->driver = driver;
1034 xpermd->used = 0;
1035 memset(xpermd->allowed->p, 0, sizeof(xpermd->allowed->p));
1036 memset(xpermd->auditallow->p, 0, sizeof(xpermd->auditallow->p));
1037 memset(xpermd->dontaudit->p, 0, sizeof(xpermd->dontaudit->p));
1038
1039 rcu_read_lock();
1040 if (!selinux_initialized(state))
1041 goto allow;
1042
1043 policy = rcu_dereference(state->policy);
1044 policydb = &policy->policydb;
1045 sidtab = policy->sidtab;
1046
1047 scontext = sidtab_search(sidtab, ssid);
1048 if (!scontext) {
1049 pr_err("SELinux: %s: unrecognized SID %d\n",
1050 __func__, ssid);
1051 goto out;
1052 }
1053
1054 tcontext = sidtab_search(sidtab, tsid);
1055 if (!tcontext) {
1056 pr_err("SELinux: %s: unrecognized SID %d\n",
1057 __func__, tsid);
1058 goto out;
1059 }
1060
1061 tclass = unmap_class(&policy->map, orig_tclass);
1062 if (unlikely(orig_tclass && !tclass)) {
1063 if (policydb->allow_unknown)
1064 goto allow;
1065 goto out;
1066 }
1067
1068
1069 if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
1070 pr_warn_ratelimited("SELinux: Invalid class %hu\n", tclass);
1071 goto out;
1072 }
1073
1074 avkey.target_class = tclass;
1075 avkey.specified = AVTAB_XPERMS;
1076 sattr = &policydb->type_attr_map_array[scontext->type - 1];
1077 tattr = &policydb->type_attr_map_array[tcontext->type - 1];
1078 ebitmap_for_each_positive_bit(sattr, snode, i) {
1079 ebitmap_for_each_positive_bit(tattr, tnode, j) {
1080 avkey.source_type = i + 1;
1081 avkey.target_type = j + 1;
1082 for (node = avtab_search_node(&policydb->te_avtab,
1083 &avkey);
1084 node;
1085 node = avtab_search_node_next(node, avkey.specified))
1086 services_compute_xperms_decision(xpermd, node);
1087
1088 cond_compute_xperms(&policydb->te_cond_avtab,
1089 &avkey, xpermd);
1090 }
1091 }
1092 out:
1093 rcu_read_unlock();
1094 return;
1095 allow:
1096 memset(xpermd->allowed->p, 0xff, sizeof(xpermd->allowed->p));
1097 goto out;
1098 }
1099
1100 /**
1101 * security_compute_av - Compute access vector decisions.
1102 * @state: SELinux state
1103 * @ssid: source security identifier
1104 * @tsid: target security identifier
1105 * @orig_tclass: target security class
1106 * @avd: access vector decisions
1107 * @xperms: extended permissions
1108 *
1109 * Compute a set of access vector decisions based on the
1110 * SID pair (@ssid, @tsid) for the permissions in @tclass.
1111 */
security_compute_av(struct selinux_state * state,u32 ssid,u32 tsid,u16 orig_tclass,struct av_decision * avd,struct extended_perms * xperms)1112 void security_compute_av(struct selinux_state *state,
1113 u32 ssid,
1114 u32 tsid,
1115 u16 orig_tclass,
1116 struct av_decision *avd,
1117 struct extended_perms *xperms)
1118 {
1119 struct selinux_policy *policy;
1120 struct policydb *policydb;
1121 struct sidtab *sidtab;
1122 u16 tclass;
1123 struct context *scontext = NULL, *tcontext = NULL;
1124
1125 rcu_read_lock();
1126 policy = rcu_dereference(state->policy);
1127 avd_init(policy, avd);
1128 xperms->len = 0;
1129 if (!selinux_initialized(state))
1130 goto allow;
1131
1132 policydb = &policy->policydb;
1133 sidtab = policy->sidtab;
1134
1135 scontext = sidtab_search(sidtab, ssid);
1136 if (!scontext) {
1137 pr_err("SELinux: %s: unrecognized SID %d\n",
1138 __func__, ssid);
1139 goto out;
1140 }
1141
1142 /* permissive domain? */
1143 if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
1144 avd->flags |= AVD_FLAGS_PERMISSIVE;
1145
1146 tcontext = sidtab_search(sidtab, tsid);
1147 if (!tcontext) {
1148 pr_err("SELinux: %s: unrecognized SID %d\n",
1149 __func__, tsid);
1150 goto out;
1151 }
1152
1153 tclass = unmap_class(&policy->map, orig_tclass);
1154 if (unlikely(orig_tclass && !tclass)) {
1155 if (policydb->allow_unknown)
1156 goto allow;
1157 goto out;
1158 }
1159 context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
1160 xperms);
1161 map_decision(&policy->map, orig_tclass, avd,
1162 policydb->allow_unknown);
1163 out:
1164 rcu_read_unlock();
1165 return;
1166 allow:
1167 avd->allowed = 0xffffffff;
1168 goto out;
1169 }
1170
security_compute_av_user(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,struct av_decision * avd)1171 void security_compute_av_user(struct selinux_state *state,
1172 u32 ssid,
1173 u32 tsid,
1174 u16 tclass,
1175 struct av_decision *avd)
1176 {
1177 struct selinux_policy *policy;
1178 struct policydb *policydb;
1179 struct sidtab *sidtab;
1180 struct context *scontext = NULL, *tcontext = NULL;
1181
1182 rcu_read_lock();
1183 policy = rcu_dereference(state->policy);
1184 avd_init(policy, avd);
1185 if (!selinux_initialized(state))
1186 goto allow;
1187
1188 policydb = &policy->policydb;
1189 sidtab = policy->sidtab;
1190
1191 scontext = sidtab_search(sidtab, ssid);
1192 if (!scontext) {
1193 pr_err("SELinux: %s: unrecognized SID %d\n",
1194 __func__, ssid);
1195 goto out;
1196 }
1197
1198 /* permissive domain? */
1199 if (ebitmap_get_bit(&policydb->permissive_map, scontext->type))
1200 avd->flags |= AVD_FLAGS_PERMISSIVE;
1201
1202 tcontext = sidtab_search(sidtab, tsid);
1203 if (!tcontext) {
1204 pr_err("SELinux: %s: unrecognized SID %d\n",
1205 __func__, tsid);
1206 goto out;
1207 }
1208
1209 if (unlikely(!tclass)) {
1210 if (policydb->allow_unknown)
1211 goto allow;
1212 goto out;
1213 }
1214
1215 context_struct_compute_av(policydb, scontext, tcontext, tclass, avd,
1216 NULL);
1217 out:
1218 rcu_read_unlock();
1219 return;
1220 allow:
1221 avd->allowed = 0xffffffff;
1222 goto out;
1223 }
1224
1225 /*
1226 * Write the security context string representation of
1227 * the context structure `context' into a dynamically
1228 * allocated string of the correct size. Set `*scontext'
1229 * to point to this string and set `*scontext_len' to
1230 * the length of the string.
1231 */
context_struct_to_string(struct policydb * p,struct context * context,char ** scontext,u32 * scontext_len)1232 static int context_struct_to_string(struct policydb *p,
1233 struct context *context,
1234 char **scontext, u32 *scontext_len)
1235 {
1236 char *scontextp;
1237
1238 if (scontext)
1239 *scontext = NULL;
1240 *scontext_len = 0;
1241
1242 if (context->len) {
1243 *scontext_len = context->len;
1244 if (scontext) {
1245 *scontext = kstrdup(context->str, GFP_ATOMIC);
1246 if (!(*scontext))
1247 return -ENOMEM;
1248 }
1249 return 0;
1250 }
1251
1252 /* Compute the size of the context. */
1253 *scontext_len += strlen(sym_name(p, SYM_USERS, context->user - 1)) + 1;
1254 *scontext_len += strlen(sym_name(p, SYM_ROLES, context->role - 1)) + 1;
1255 *scontext_len += strlen(sym_name(p, SYM_TYPES, context->type - 1)) + 1;
1256 *scontext_len += mls_compute_context_len(p, context);
1257
1258 if (!scontext)
1259 return 0;
1260
1261 /* Allocate space for the context; caller must free this space. */
1262 scontextp = kmalloc(*scontext_len, GFP_ATOMIC);
1263 if (!scontextp)
1264 return -ENOMEM;
1265 *scontext = scontextp;
1266
1267 /*
1268 * Copy the user name, role name and type name into the context.
1269 */
1270 scontextp += sprintf(scontextp, "%s:%s:%s",
1271 sym_name(p, SYM_USERS, context->user - 1),
1272 sym_name(p, SYM_ROLES, context->role - 1),
1273 sym_name(p, SYM_TYPES, context->type - 1));
1274
1275 mls_sid_to_context(p, context, &scontextp);
1276
1277 *scontextp = 0;
1278
1279 return 0;
1280 }
1281
sidtab_entry_to_string(struct policydb * p,struct sidtab * sidtab,struct sidtab_entry * entry,char ** scontext,u32 * scontext_len)1282 static int sidtab_entry_to_string(struct policydb *p,
1283 struct sidtab *sidtab,
1284 struct sidtab_entry *entry,
1285 char **scontext, u32 *scontext_len)
1286 {
1287 int rc = sidtab_sid2str_get(sidtab, entry, scontext, scontext_len);
1288
1289 if (rc != -ENOENT)
1290 return rc;
1291
1292 rc = context_struct_to_string(p, &entry->context, scontext,
1293 scontext_len);
1294 if (!rc && scontext)
1295 sidtab_sid2str_put(sidtab, entry, *scontext, *scontext_len);
1296 return rc;
1297 }
1298
1299 #include "initial_sid_to_string.h"
1300
security_sidtab_hash_stats(struct selinux_state * state,char * page)1301 int security_sidtab_hash_stats(struct selinux_state *state, char *page)
1302 {
1303 struct selinux_policy *policy;
1304 int rc;
1305
1306 if (!selinux_initialized(state)) {
1307 pr_err("SELinux: %s: called before initial load_policy\n",
1308 __func__);
1309 return -EINVAL;
1310 }
1311
1312 rcu_read_lock();
1313 policy = rcu_dereference(state->policy);
1314 rc = sidtab_hash_stats(policy->sidtab, page);
1315 rcu_read_unlock();
1316
1317 return rc;
1318 }
1319
security_get_initial_sid_context(u32 sid)1320 const char *security_get_initial_sid_context(u32 sid)
1321 {
1322 if (unlikely(sid > SECINITSID_NUM))
1323 return NULL;
1324 return initial_sid_to_string[sid];
1325 }
1326
security_sid_to_context_core(struct selinux_state * state,u32 sid,char ** scontext,u32 * scontext_len,int force,int only_invalid)1327 static int security_sid_to_context_core(struct selinux_state *state,
1328 u32 sid, char **scontext,
1329 u32 *scontext_len, int force,
1330 int only_invalid)
1331 {
1332 struct selinux_policy *policy;
1333 struct policydb *policydb;
1334 struct sidtab *sidtab;
1335 struct sidtab_entry *entry;
1336 int rc = 0;
1337
1338 if (scontext)
1339 *scontext = NULL;
1340 *scontext_len = 0;
1341
1342 if (!selinux_initialized(state)) {
1343 if (sid <= SECINITSID_NUM) {
1344 char *scontextp;
1345 const char *s = initial_sid_to_string[sid];
1346
1347 if (!s)
1348 return -EINVAL;
1349 *scontext_len = strlen(s) + 1;
1350 if (!scontext)
1351 return 0;
1352 scontextp = kmemdup(s, *scontext_len, GFP_ATOMIC);
1353 if (!scontextp)
1354 return -ENOMEM;
1355 *scontext = scontextp;
1356 return 0;
1357 }
1358 pr_err("SELinux: %s: called before initial "
1359 "load_policy on unknown SID %d\n", __func__, sid);
1360 return -EINVAL;
1361 }
1362 rcu_read_lock();
1363 policy = rcu_dereference(state->policy);
1364 policydb = &policy->policydb;
1365 sidtab = policy->sidtab;
1366
1367 if (force)
1368 entry = sidtab_search_entry_force(sidtab, sid);
1369 else
1370 entry = sidtab_search_entry(sidtab, sid);
1371 if (!entry) {
1372 pr_err("SELinux: %s: unrecognized SID %d\n",
1373 __func__, sid);
1374 rc = -EINVAL;
1375 goto out_unlock;
1376 }
1377 if (only_invalid && !entry->context.len)
1378 goto out_unlock;
1379
1380 rc = sidtab_entry_to_string(policydb, sidtab, entry, scontext,
1381 scontext_len);
1382
1383 out_unlock:
1384 rcu_read_unlock();
1385 return rc;
1386
1387 }
1388
1389 /**
1390 * security_sid_to_context - Obtain a context for a given SID.
1391 * @state: SELinux state
1392 * @sid: security identifier, SID
1393 * @scontext: security context
1394 * @scontext_len: length in bytes
1395 *
1396 * Write the string representation of the context associated with @sid
1397 * into a dynamically allocated string of the correct size. Set @scontext
1398 * to point to this string and set @scontext_len to the length of the string.
1399 */
security_sid_to_context(struct selinux_state * state,u32 sid,char ** scontext,u32 * scontext_len)1400 int security_sid_to_context(struct selinux_state *state,
1401 u32 sid, char **scontext, u32 *scontext_len)
1402 {
1403 return security_sid_to_context_core(state, sid, scontext,
1404 scontext_len, 0, 0);
1405 }
1406
security_sid_to_context_force(struct selinux_state * state,u32 sid,char ** scontext,u32 * scontext_len)1407 int security_sid_to_context_force(struct selinux_state *state, u32 sid,
1408 char **scontext, u32 *scontext_len)
1409 {
1410 return security_sid_to_context_core(state, sid, scontext,
1411 scontext_len, 1, 0);
1412 }
1413
1414 /**
1415 * security_sid_to_context_inval - Obtain a context for a given SID if it
1416 * is invalid.
1417 * @state: SELinux state
1418 * @sid: security identifier, SID
1419 * @scontext: security context
1420 * @scontext_len: length in bytes
1421 *
1422 * Write the string representation of the context associated with @sid
1423 * into a dynamically allocated string of the correct size, but only if the
1424 * context is invalid in the current policy. Set @scontext to point to
1425 * this string (or NULL if the context is valid) and set @scontext_len to
1426 * the length of the string (or 0 if the context is valid).
1427 */
security_sid_to_context_inval(struct selinux_state * state,u32 sid,char ** scontext,u32 * scontext_len)1428 int security_sid_to_context_inval(struct selinux_state *state, u32 sid,
1429 char **scontext, u32 *scontext_len)
1430 {
1431 return security_sid_to_context_core(state, sid, scontext,
1432 scontext_len, 1, 1);
1433 }
1434
1435 /*
1436 * Caveat: Mutates scontext.
1437 */
string_to_context_struct(struct policydb * pol,struct sidtab * sidtabp,char * scontext,struct context * ctx,u32 def_sid)1438 static int string_to_context_struct(struct policydb *pol,
1439 struct sidtab *sidtabp,
1440 char *scontext,
1441 struct context *ctx,
1442 u32 def_sid)
1443 {
1444 struct role_datum *role;
1445 struct type_datum *typdatum;
1446 struct user_datum *usrdatum;
1447 char *scontextp, *p, oldc;
1448 int rc = 0;
1449
1450 context_init(ctx);
1451
1452 /* Parse the security context. */
1453
1454 rc = -EINVAL;
1455 scontextp = (char *) scontext;
1456
1457 /* Extract the user. */
1458 p = scontextp;
1459 while (*p && *p != ':')
1460 p++;
1461
1462 if (*p == 0)
1463 goto out;
1464
1465 *p++ = 0;
1466
1467 usrdatum = symtab_search(&pol->p_users, scontextp);
1468 if (!usrdatum)
1469 goto out;
1470
1471 ctx->user = usrdatum->value;
1472
1473 /* Extract role. */
1474 scontextp = p;
1475 while (*p && *p != ':')
1476 p++;
1477
1478 if (*p == 0)
1479 goto out;
1480
1481 *p++ = 0;
1482
1483 role = symtab_search(&pol->p_roles, scontextp);
1484 if (!role)
1485 goto out;
1486 ctx->role = role->value;
1487
1488 /* Extract type. */
1489 scontextp = p;
1490 while (*p && *p != ':')
1491 p++;
1492 oldc = *p;
1493 *p++ = 0;
1494
1495 typdatum = symtab_search(&pol->p_types, scontextp);
1496 if (!typdatum || typdatum->attribute)
1497 goto out;
1498
1499 ctx->type = typdatum->value;
1500
1501 rc = mls_context_to_sid(pol, oldc, p, ctx, sidtabp, def_sid);
1502 if (rc)
1503 goto out;
1504
1505 /* Check the validity of the new context. */
1506 rc = -EINVAL;
1507 if (!policydb_context_isvalid(pol, ctx))
1508 goto out;
1509 rc = 0;
1510 out:
1511 if (rc)
1512 context_destroy(ctx);
1513 return rc;
1514 }
1515
security_context_to_sid_core(struct selinux_state * state,const char * scontext,u32 scontext_len,u32 * sid,u32 def_sid,gfp_t gfp_flags,int force)1516 static int security_context_to_sid_core(struct selinux_state *state,
1517 const char *scontext, u32 scontext_len,
1518 u32 *sid, u32 def_sid, gfp_t gfp_flags,
1519 int force)
1520 {
1521 struct selinux_policy *policy;
1522 struct policydb *policydb;
1523 struct sidtab *sidtab;
1524 char *scontext2, *str = NULL;
1525 struct context context;
1526 int rc = 0;
1527
1528 /* An empty security context is never valid. */
1529 if (!scontext_len)
1530 return -EINVAL;
1531
1532 /* Copy the string to allow changes and ensure a NUL terminator */
1533 scontext2 = kmemdup_nul(scontext, scontext_len, gfp_flags);
1534 if (!scontext2)
1535 return -ENOMEM;
1536
1537 if (!selinux_initialized(state)) {
1538 int i;
1539
1540 for (i = 1; i < SECINITSID_NUM; i++) {
1541 const char *s = initial_sid_to_string[i];
1542
1543 if (s && !strcmp(s, scontext2)) {
1544 *sid = i;
1545 goto out;
1546 }
1547 }
1548 *sid = SECINITSID_KERNEL;
1549 goto out;
1550 }
1551 *sid = SECSID_NULL;
1552
1553 if (force) {
1554 /* Save another copy for storing in uninterpreted form */
1555 rc = -ENOMEM;
1556 str = kstrdup(scontext2, gfp_flags);
1557 if (!str)
1558 goto out;
1559 }
1560 retry:
1561 rcu_read_lock();
1562 policy = rcu_dereference(state->policy);
1563 policydb = &policy->policydb;
1564 sidtab = policy->sidtab;
1565 rc = string_to_context_struct(policydb, sidtab, scontext2,
1566 &context, def_sid);
1567 if (rc == -EINVAL && force) {
1568 context.str = str;
1569 context.len = strlen(str) + 1;
1570 str = NULL;
1571 } else if (rc)
1572 goto out_unlock;
1573 rc = sidtab_context_to_sid(sidtab, &context, sid);
1574 if (rc == -ESTALE) {
1575 rcu_read_unlock();
1576 if (context.str) {
1577 str = context.str;
1578 context.str = NULL;
1579 }
1580 context_destroy(&context);
1581 goto retry;
1582 }
1583 context_destroy(&context);
1584 out_unlock:
1585 rcu_read_unlock();
1586 out:
1587 kfree(scontext2);
1588 kfree(str);
1589 return rc;
1590 }
1591
1592 /**
1593 * security_context_to_sid - Obtain a SID for a given security context.
1594 * @state: SELinux state
1595 * @scontext: security context
1596 * @scontext_len: length in bytes
1597 * @sid: security identifier, SID
1598 * @gfp: context for the allocation
1599 *
1600 * Obtains a SID associated with the security context that
1601 * has the string representation specified by @scontext.
1602 * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1603 * memory is available, or 0 on success.
1604 */
security_context_to_sid(struct selinux_state * state,const char * scontext,u32 scontext_len,u32 * sid,gfp_t gfp)1605 int security_context_to_sid(struct selinux_state *state,
1606 const char *scontext, u32 scontext_len, u32 *sid,
1607 gfp_t gfp)
1608 {
1609 return security_context_to_sid_core(state, scontext, scontext_len,
1610 sid, SECSID_NULL, gfp, 0);
1611 }
1612
security_context_str_to_sid(struct selinux_state * state,const char * scontext,u32 * sid,gfp_t gfp)1613 int security_context_str_to_sid(struct selinux_state *state,
1614 const char *scontext, u32 *sid, gfp_t gfp)
1615 {
1616 return security_context_to_sid(state, scontext, strlen(scontext),
1617 sid, gfp);
1618 }
1619
1620 /**
1621 * security_context_to_sid_default - Obtain a SID for a given security context,
1622 * falling back to specified default if needed.
1623 *
1624 * @state: SELinux state
1625 * @scontext: security context
1626 * @scontext_len: length in bytes
1627 * @sid: security identifier, SID
1628 * @def_sid: default SID to assign on error
1629 * @gfp_flags: the allocator get-free-page (GFP) flags
1630 *
1631 * Obtains a SID associated with the security context that
1632 * has the string representation specified by @scontext.
1633 * The default SID is passed to the MLS layer to be used to allow
1634 * kernel labeling of the MLS field if the MLS field is not present
1635 * (for upgrading to MLS without full relabel).
1636 * Implicitly forces adding of the context even if it cannot be mapped yet.
1637 * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1638 * memory is available, or 0 on success.
1639 */
security_context_to_sid_default(struct selinux_state * state,const char * scontext,u32 scontext_len,u32 * sid,u32 def_sid,gfp_t gfp_flags)1640 int security_context_to_sid_default(struct selinux_state *state,
1641 const char *scontext, u32 scontext_len,
1642 u32 *sid, u32 def_sid, gfp_t gfp_flags)
1643 {
1644 return security_context_to_sid_core(state, scontext, scontext_len,
1645 sid, def_sid, gfp_flags, 1);
1646 }
1647
security_context_to_sid_force(struct selinux_state * state,const char * scontext,u32 scontext_len,u32 * sid)1648 int security_context_to_sid_force(struct selinux_state *state,
1649 const char *scontext, u32 scontext_len,
1650 u32 *sid)
1651 {
1652 return security_context_to_sid_core(state, scontext, scontext_len,
1653 sid, SECSID_NULL, GFP_KERNEL, 1);
1654 }
1655
compute_sid_handle_invalid_context(struct selinux_state * state,struct selinux_policy * policy,struct sidtab_entry * sentry,struct sidtab_entry * tentry,u16 tclass,struct context * newcontext)1656 static int compute_sid_handle_invalid_context(
1657 struct selinux_state *state,
1658 struct selinux_policy *policy,
1659 struct sidtab_entry *sentry,
1660 struct sidtab_entry *tentry,
1661 u16 tclass,
1662 struct context *newcontext)
1663 {
1664 struct policydb *policydb = &policy->policydb;
1665 struct sidtab *sidtab = policy->sidtab;
1666 char *s = NULL, *t = NULL, *n = NULL;
1667 u32 slen, tlen, nlen;
1668 struct audit_buffer *ab;
1669
1670 if (sidtab_entry_to_string(policydb, sidtab, sentry, &s, &slen))
1671 goto out;
1672 if (sidtab_entry_to_string(policydb, sidtab, tentry, &t, &tlen))
1673 goto out;
1674 if (context_struct_to_string(policydb, newcontext, &n, &nlen))
1675 goto out;
1676 ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR);
1677 if (!ab)
1678 goto out;
1679 audit_log_format(ab,
1680 "op=security_compute_sid invalid_context=");
1681 /* no need to record the NUL with untrusted strings */
1682 audit_log_n_untrustedstring(ab, n, nlen - 1);
1683 audit_log_format(ab, " scontext=%s tcontext=%s tclass=%s",
1684 s, t, sym_name(policydb, SYM_CLASSES, tclass-1));
1685 audit_log_end(ab);
1686 out:
1687 kfree(s);
1688 kfree(t);
1689 kfree(n);
1690 if (!enforcing_enabled(state))
1691 return 0;
1692 return -EACCES;
1693 }
1694
filename_compute_type(struct policydb * policydb,struct context * newcontext,u32 stype,u32 ttype,u16 tclass,const char * objname)1695 static void filename_compute_type(struct policydb *policydb,
1696 struct context *newcontext,
1697 u32 stype, u32 ttype, u16 tclass,
1698 const char *objname)
1699 {
1700 struct filename_trans_key ft;
1701 struct filename_trans_datum *datum;
1702
1703 /*
1704 * Most filename trans rules are going to live in specific directories
1705 * like /dev or /var/run. This bitmap will quickly skip rule searches
1706 * if the ttype does not contain any rules.
1707 */
1708 if (!ebitmap_get_bit(&policydb->filename_trans_ttypes, ttype))
1709 return;
1710
1711 ft.ttype = ttype;
1712 ft.tclass = tclass;
1713 ft.name = objname;
1714
1715 datum = policydb_filenametr_search(policydb, &ft);
1716 while (datum) {
1717 if (ebitmap_get_bit(&datum->stypes, stype - 1)) {
1718 newcontext->type = datum->otype;
1719 return;
1720 }
1721 datum = datum->next;
1722 }
1723 }
1724
security_compute_sid(struct selinux_state * state,u32 ssid,u32 tsid,u16 orig_tclass,u32 specified,const char * objname,u32 * out_sid,bool kern)1725 static int security_compute_sid(struct selinux_state *state,
1726 u32 ssid,
1727 u32 tsid,
1728 u16 orig_tclass,
1729 u32 specified,
1730 const char *objname,
1731 u32 *out_sid,
1732 bool kern)
1733 {
1734 struct selinux_policy *policy;
1735 struct policydb *policydb;
1736 struct sidtab *sidtab;
1737 struct class_datum *cladatum;
1738 struct context *scontext, *tcontext, newcontext;
1739 struct sidtab_entry *sentry, *tentry;
1740 struct avtab_key avkey;
1741 struct avtab_datum *avdatum;
1742 struct avtab_node *node;
1743 u16 tclass;
1744 int rc = 0;
1745 bool sock;
1746
1747 if (!selinux_initialized(state)) {
1748 switch (orig_tclass) {
1749 case SECCLASS_PROCESS: /* kernel value */
1750 *out_sid = ssid;
1751 break;
1752 default:
1753 *out_sid = tsid;
1754 break;
1755 }
1756 goto out;
1757 }
1758
1759 retry:
1760 cladatum = NULL;
1761 context_init(&newcontext);
1762
1763 rcu_read_lock();
1764
1765 policy = rcu_dereference(state->policy);
1766
1767 if (kern) {
1768 tclass = unmap_class(&policy->map, orig_tclass);
1769 sock = security_is_socket_class(orig_tclass);
1770 } else {
1771 tclass = orig_tclass;
1772 sock = security_is_socket_class(map_class(&policy->map,
1773 tclass));
1774 }
1775
1776 policydb = &policy->policydb;
1777 sidtab = policy->sidtab;
1778
1779 sentry = sidtab_search_entry(sidtab, ssid);
1780 if (!sentry) {
1781 pr_err("SELinux: %s: unrecognized SID %d\n",
1782 __func__, ssid);
1783 rc = -EINVAL;
1784 goto out_unlock;
1785 }
1786 tentry = sidtab_search_entry(sidtab, tsid);
1787 if (!tentry) {
1788 pr_err("SELinux: %s: unrecognized SID %d\n",
1789 __func__, tsid);
1790 rc = -EINVAL;
1791 goto out_unlock;
1792 }
1793
1794 scontext = &sentry->context;
1795 tcontext = &tentry->context;
1796
1797 if (tclass && tclass <= policydb->p_classes.nprim)
1798 cladatum = policydb->class_val_to_struct[tclass - 1];
1799
1800 /* Set the user identity. */
1801 switch (specified) {
1802 case AVTAB_TRANSITION:
1803 case AVTAB_CHANGE:
1804 if (cladatum && cladatum->default_user == DEFAULT_TARGET) {
1805 newcontext.user = tcontext->user;
1806 } else {
1807 /* notice this gets both DEFAULT_SOURCE and unset */
1808 /* Use the process user identity. */
1809 newcontext.user = scontext->user;
1810 }
1811 break;
1812 case AVTAB_MEMBER:
1813 /* Use the related object owner. */
1814 newcontext.user = tcontext->user;
1815 break;
1816 }
1817
1818 /* Set the role to default values. */
1819 if (cladatum && cladatum->default_role == DEFAULT_SOURCE) {
1820 newcontext.role = scontext->role;
1821 } else if (cladatum && cladatum->default_role == DEFAULT_TARGET) {
1822 newcontext.role = tcontext->role;
1823 } else {
1824 if ((tclass == policydb->process_class) || sock)
1825 newcontext.role = scontext->role;
1826 else
1827 newcontext.role = OBJECT_R_VAL;
1828 }
1829
1830 /* Set the type to default values. */
1831 if (cladatum && cladatum->default_type == DEFAULT_SOURCE) {
1832 newcontext.type = scontext->type;
1833 } else if (cladatum && cladatum->default_type == DEFAULT_TARGET) {
1834 newcontext.type = tcontext->type;
1835 } else {
1836 if ((tclass == policydb->process_class) || sock) {
1837 /* Use the type of process. */
1838 newcontext.type = scontext->type;
1839 } else {
1840 /* Use the type of the related object. */
1841 newcontext.type = tcontext->type;
1842 }
1843 }
1844
1845 /* Look for a type transition/member/change rule. */
1846 avkey.source_type = scontext->type;
1847 avkey.target_type = tcontext->type;
1848 avkey.target_class = tclass;
1849 avkey.specified = specified;
1850 avdatum = avtab_search(&policydb->te_avtab, &avkey);
1851
1852 /* If no permanent rule, also check for enabled conditional rules */
1853 if (!avdatum) {
1854 node = avtab_search_node(&policydb->te_cond_avtab, &avkey);
1855 for (; node; node = avtab_search_node_next(node, specified)) {
1856 if (node->key.specified & AVTAB_ENABLED) {
1857 avdatum = &node->datum;
1858 break;
1859 }
1860 }
1861 }
1862
1863 if (avdatum) {
1864 /* Use the type from the type transition/member/change rule. */
1865 newcontext.type = avdatum->u.data;
1866 }
1867
1868 /* if we have a objname this is a file trans check so check those rules */
1869 if (objname)
1870 filename_compute_type(policydb, &newcontext, scontext->type,
1871 tcontext->type, tclass, objname);
1872
1873 /* Check for class-specific changes. */
1874 if (specified & AVTAB_TRANSITION) {
1875 /* Look for a role transition rule. */
1876 struct role_trans_datum *rtd;
1877 struct role_trans_key rtk = {
1878 .role = scontext->role,
1879 .type = tcontext->type,
1880 .tclass = tclass,
1881 };
1882
1883 rtd = policydb_roletr_search(policydb, &rtk);
1884 if (rtd)
1885 newcontext.role = rtd->new_role;
1886 }
1887
1888 /* Set the MLS attributes.
1889 This is done last because it may allocate memory. */
1890 rc = mls_compute_sid(policydb, scontext, tcontext, tclass, specified,
1891 &newcontext, sock);
1892 if (rc)
1893 goto out_unlock;
1894
1895 /* Check the validity of the context. */
1896 if (!policydb_context_isvalid(policydb, &newcontext)) {
1897 rc = compute_sid_handle_invalid_context(state, policy, sentry,
1898 tentry, tclass,
1899 &newcontext);
1900 if (rc)
1901 goto out_unlock;
1902 }
1903 /* Obtain the sid for the context. */
1904 rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
1905 if (rc == -ESTALE) {
1906 rcu_read_unlock();
1907 context_destroy(&newcontext);
1908 goto retry;
1909 }
1910 out_unlock:
1911 rcu_read_unlock();
1912 context_destroy(&newcontext);
1913 out:
1914 return rc;
1915 }
1916
1917 /**
1918 * security_transition_sid - Compute the SID for a new subject/object.
1919 * @state: SELinux state
1920 * @ssid: source security identifier
1921 * @tsid: target security identifier
1922 * @tclass: target security class
1923 * @qstr: object name
1924 * @out_sid: security identifier for new subject/object
1925 *
1926 * Compute a SID to use for labeling a new subject or object in the
1927 * class @tclass based on a SID pair (@ssid, @tsid).
1928 * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1929 * if insufficient memory is available, or %0 if the new SID was
1930 * computed successfully.
1931 */
security_transition_sid(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,const struct qstr * qstr,u32 * out_sid)1932 int security_transition_sid(struct selinux_state *state,
1933 u32 ssid, u32 tsid, u16 tclass,
1934 const struct qstr *qstr, u32 *out_sid)
1935 {
1936 return security_compute_sid(state, ssid, tsid, tclass,
1937 AVTAB_TRANSITION,
1938 qstr ? qstr->name : NULL, out_sid, true);
1939 }
1940
security_transition_sid_user(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,const char * objname,u32 * out_sid)1941 int security_transition_sid_user(struct selinux_state *state,
1942 u32 ssid, u32 tsid, u16 tclass,
1943 const char *objname, u32 *out_sid)
1944 {
1945 return security_compute_sid(state, ssid, tsid, tclass,
1946 AVTAB_TRANSITION,
1947 objname, out_sid, false);
1948 }
1949
1950 /**
1951 * security_member_sid - Compute the SID for member selection.
1952 * @state: SELinux state
1953 * @ssid: source security identifier
1954 * @tsid: target security identifier
1955 * @tclass: target security class
1956 * @out_sid: security identifier for selected member
1957 *
1958 * Compute a SID to use when selecting a member of a polyinstantiated
1959 * object of class @tclass based on a SID pair (@ssid, @tsid).
1960 * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1961 * if insufficient memory is available, or %0 if the SID was
1962 * computed successfully.
1963 */
security_member_sid(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,u32 * out_sid)1964 int security_member_sid(struct selinux_state *state,
1965 u32 ssid,
1966 u32 tsid,
1967 u16 tclass,
1968 u32 *out_sid)
1969 {
1970 return security_compute_sid(state, ssid, tsid, tclass,
1971 AVTAB_MEMBER, NULL,
1972 out_sid, false);
1973 }
1974
1975 /**
1976 * security_change_sid - Compute the SID for object relabeling.
1977 * @state: SELinux state
1978 * @ssid: source security identifier
1979 * @tsid: target security identifier
1980 * @tclass: target security class
1981 * @out_sid: security identifier for selected member
1982 *
1983 * Compute a SID to use for relabeling an object of class @tclass
1984 * based on a SID pair (@ssid, @tsid).
1985 * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1986 * if insufficient memory is available, or %0 if the SID was
1987 * computed successfully.
1988 */
security_change_sid(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,u32 * out_sid)1989 int security_change_sid(struct selinux_state *state,
1990 u32 ssid,
1991 u32 tsid,
1992 u16 tclass,
1993 u32 *out_sid)
1994 {
1995 return security_compute_sid(state,
1996 ssid, tsid, tclass, AVTAB_CHANGE, NULL,
1997 out_sid, false);
1998 }
1999
convert_context_handle_invalid_context(struct selinux_state * state,struct policydb * policydb,struct context * context)2000 static inline int convert_context_handle_invalid_context(
2001 struct selinux_state *state,
2002 struct policydb *policydb,
2003 struct context *context)
2004 {
2005 char *s;
2006 u32 len;
2007
2008 if (enforcing_enabled(state))
2009 return -EINVAL;
2010
2011 if (!context_struct_to_string(policydb, context, &s, &len)) {
2012 pr_warn("SELinux: Context %s would be invalid if enforcing\n",
2013 s);
2014 kfree(s);
2015 }
2016 return 0;
2017 }
2018
2019 /*
2020 * Convert the values in the security context
2021 * structure `oldc' from the values specified
2022 * in the policy `p->oldp' to the values specified
2023 * in the policy `p->newp', storing the new context
2024 * in `newc'. Verify that the context is valid
2025 * under the new policy.
2026 */
convert_context(struct context * oldc,struct context * newc,void * p)2027 static int convert_context(struct context *oldc, struct context *newc, void *p)
2028 {
2029 struct convert_context_args *args;
2030 struct ocontext *oc;
2031 struct role_datum *role;
2032 struct type_datum *typdatum;
2033 struct user_datum *usrdatum;
2034 char *s;
2035 u32 len;
2036 int rc;
2037
2038 args = p;
2039
2040 if (oldc->str) {
2041 s = kstrdup(oldc->str, GFP_KERNEL);
2042 if (!s)
2043 return -ENOMEM;
2044
2045 rc = string_to_context_struct(args->newp, NULL, s,
2046 newc, SECSID_NULL);
2047 if (rc == -EINVAL) {
2048 /*
2049 * Retain string representation for later mapping.
2050 *
2051 * IMPORTANT: We need to copy the contents of oldc->str
2052 * back into s again because string_to_context_struct()
2053 * may have garbled it.
2054 */
2055 memcpy(s, oldc->str, oldc->len);
2056 context_init(newc);
2057 newc->str = s;
2058 newc->len = oldc->len;
2059 return 0;
2060 }
2061 kfree(s);
2062 if (rc) {
2063 /* Other error condition, e.g. ENOMEM. */
2064 pr_err("SELinux: Unable to map context %s, rc = %d.\n",
2065 oldc->str, -rc);
2066 return rc;
2067 }
2068 pr_info("SELinux: Context %s became valid (mapped).\n",
2069 oldc->str);
2070 return 0;
2071 }
2072
2073 context_init(newc);
2074
2075 /* Convert the user. */
2076 usrdatum = symtab_search(&args->newp->p_users,
2077 sym_name(args->oldp,
2078 SYM_USERS, oldc->user - 1));
2079 if (!usrdatum)
2080 goto bad;
2081 newc->user = usrdatum->value;
2082
2083 /* Convert the role. */
2084 role = symtab_search(&args->newp->p_roles,
2085 sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
2086 if (!role)
2087 goto bad;
2088 newc->role = role->value;
2089
2090 /* Convert the type. */
2091 typdatum = symtab_search(&args->newp->p_types,
2092 sym_name(args->oldp,
2093 SYM_TYPES, oldc->type - 1));
2094 if (!typdatum)
2095 goto bad;
2096 newc->type = typdatum->value;
2097
2098 /* Convert the MLS fields if dealing with MLS policies */
2099 if (args->oldp->mls_enabled && args->newp->mls_enabled) {
2100 rc = mls_convert_context(args->oldp, args->newp, oldc, newc);
2101 if (rc)
2102 goto bad;
2103 } else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
2104 /*
2105 * Switching between non-MLS and MLS policy:
2106 * ensure that the MLS fields of the context for all
2107 * existing entries in the sidtab are filled in with a
2108 * suitable default value, likely taken from one of the
2109 * initial SIDs.
2110 */
2111 oc = args->newp->ocontexts[OCON_ISID];
2112 while (oc && oc->sid[0] != SECINITSID_UNLABELED)
2113 oc = oc->next;
2114 if (!oc) {
2115 pr_err("SELinux: unable to look up"
2116 " the initial SIDs list\n");
2117 goto bad;
2118 }
2119 rc = mls_range_set(newc, &oc->context[0].range);
2120 if (rc)
2121 goto bad;
2122 }
2123
2124 /* Check the validity of the new context. */
2125 if (!policydb_context_isvalid(args->newp, newc)) {
2126 rc = convert_context_handle_invalid_context(args->state,
2127 args->oldp,
2128 oldc);
2129 if (rc)
2130 goto bad;
2131 }
2132
2133 return 0;
2134 bad:
2135 /* Map old representation to string and save it. */
2136 rc = context_struct_to_string(args->oldp, oldc, &s, &len);
2137 if (rc)
2138 return rc;
2139 context_destroy(newc);
2140 newc->str = s;
2141 newc->len = len;
2142 pr_info("SELinux: Context %s became invalid (unmapped).\n",
2143 newc->str);
2144 return 0;
2145 }
2146
security_load_policycaps(struct selinux_state * state,struct selinux_policy * policy)2147 static void security_load_policycaps(struct selinux_state *state,
2148 struct selinux_policy *policy)
2149 {
2150 struct policydb *p;
2151 unsigned int i;
2152 struct ebitmap_node *node;
2153
2154 p = &policy->policydb;
2155
2156 for (i = 0; i < ARRAY_SIZE(state->policycap); i++)
2157 WRITE_ONCE(state->policycap[i],
2158 ebitmap_get_bit(&p->policycaps, i));
2159
2160 for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
2161 pr_info("SELinux: policy capability %s=%d\n",
2162 selinux_policycap_names[i],
2163 ebitmap_get_bit(&p->policycaps, i));
2164
2165 ebitmap_for_each_positive_bit(&p->policycaps, node, i) {
2166 if (i >= ARRAY_SIZE(selinux_policycap_names))
2167 pr_info("SELinux: unknown policy capability %u\n",
2168 i);
2169 }
2170 }
2171
2172 static int security_preserve_bools(struct selinux_policy *oldpolicy,
2173 struct selinux_policy *newpolicy);
2174
selinux_policy_free(struct selinux_policy * policy)2175 static void selinux_policy_free(struct selinux_policy *policy)
2176 {
2177 if (!policy)
2178 return;
2179
2180 sidtab_destroy(policy->sidtab);
2181 kfree(policy->map.mapping);
2182 policydb_destroy(&policy->policydb);
2183 kfree(policy->sidtab);
2184 kfree(policy);
2185 }
2186
selinux_policy_cond_free(struct selinux_policy * policy)2187 static void selinux_policy_cond_free(struct selinux_policy *policy)
2188 {
2189 cond_policydb_destroy_dup(&policy->policydb);
2190 kfree(policy);
2191 }
2192
selinux_policy_cancel(struct selinux_state * state,struct selinux_load_state * load_state)2193 void selinux_policy_cancel(struct selinux_state *state,
2194 struct selinux_load_state *load_state)
2195 {
2196 struct selinux_policy *oldpolicy;
2197
2198 oldpolicy = rcu_dereference_protected(state->policy,
2199 lockdep_is_held(&state->policy_mutex));
2200
2201 sidtab_cancel_convert(oldpolicy->sidtab);
2202 selinux_policy_free(load_state->policy);
2203 kfree(load_state->convert_data);
2204 }
2205
selinux_notify_policy_change(struct selinux_state * state,u32 seqno)2206 static void selinux_notify_policy_change(struct selinux_state *state,
2207 u32 seqno)
2208 {
2209 /* Flush external caches and notify userspace of policy load */
2210 avc_ss_reset(state->avc, seqno);
2211 selnl_notify_policyload(seqno);
2212 selinux_status_update_policyload(state, seqno);
2213 selinux_netlbl_cache_invalidate();
2214 selinux_xfrm_notify_policyload();
2215 selinux_ima_measure_state_locked(state);
2216 }
2217
selinux_policy_commit(struct selinux_state * state,struct selinux_load_state * load_state)2218 void selinux_policy_commit(struct selinux_state *state,
2219 struct selinux_load_state *load_state)
2220 {
2221 struct selinux_policy *oldpolicy, *newpolicy = load_state->policy;
2222 unsigned long flags;
2223 u32 seqno;
2224
2225 oldpolicy = rcu_dereference_protected(state->policy,
2226 lockdep_is_held(&state->policy_mutex));
2227
2228 /* If switching between different policy types, log MLS status */
2229 if (oldpolicy) {
2230 if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
2231 pr_info("SELinux: Disabling MLS support...\n");
2232 else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
2233 pr_info("SELinux: Enabling MLS support...\n");
2234 }
2235
2236 /* Set latest granting seqno for new policy. */
2237 if (oldpolicy)
2238 newpolicy->latest_granting = oldpolicy->latest_granting + 1;
2239 else
2240 newpolicy->latest_granting = 1;
2241 seqno = newpolicy->latest_granting;
2242
2243 /* Install the new policy. */
2244 if (oldpolicy) {
2245 sidtab_freeze_begin(oldpolicy->sidtab, &flags);
2246 rcu_assign_pointer(state->policy, newpolicy);
2247 sidtab_freeze_end(oldpolicy->sidtab, &flags);
2248 } else {
2249 rcu_assign_pointer(state->policy, newpolicy);
2250 }
2251
2252 /* Load the policycaps from the new policy */
2253 security_load_policycaps(state, newpolicy);
2254
2255 if (!selinux_initialized(state)) {
2256 /*
2257 * After first policy load, the security server is
2258 * marked as initialized and ready to handle requests and
2259 * any objects created prior to policy load are then labeled.
2260 */
2261 selinux_mark_initialized(state);
2262 selinux_complete_init();
2263 }
2264
2265 /* Free the old policy */
2266 synchronize_rcu();
2267 selinux_policy_free(oldpolicy);
2268 kfree(load_state->convert_data);
2269
2270 /* Notify others of the policy change */
2271 selinux_notify_policy_change(state, seqno);
2272 }
2273
2274 /**
2275 * security_load_policy - Load a security policy configuration.
2276 * @state: SELinux state
2277 * @data: binary policy data
2278 * @len: length of data in bytes
2279 * @load_state: policy load state
2280 *
2281 * Load a new set of security policy configuration data,
2282 * validate it and convert the SID table as necessary.
2283 * This function will flush the access vector cache after
2284 * loading the new policy.
2285 */
security_load_policy(struct selinux_state * state,void * data,size_t len,struct selinux_load_state * load_state)2286 int security_load_policy(struct selinux_state *state, void *data, size_t len,
2287 struct selinux_load_state *load_state)
2288 {
2289 struct selinux_policy *newpolicy, *oldpolicy;
2290 struct selinux_policy_convert_data *convert_data;
2291 int rc = 0;
2292 struct policy_file file = { data, len }, *fp = &file;
2293
2294 newpolicy = kzalloc(sizeof(*newpolicy), GFP_KERNEL);
2295 if (!newpolicy)
2296 return -ENOMEM;
2297
2298 newpolicy->sidtab = kzalloc(sizeof(*newpolicy->sidtab), GFP_KERNEL);
2299 if (!newpolicy->sidtab) {
2300 rc = -ENOMEM;
2301 goto err_policy;
2302 }
2303
2304 rc = policydb_read(&newpolicy->policydb, fp);
2305 if (rc)
2306 goto err_sidtab;
2307
2308 newpolicy->policydb.len = len;
2309 rc = selinux_set_mapping(&newpolicy->policydb, secclass_map,
2310 &newpolicy->map);
2311 if (rc)
2312 goto err_policydb;
2313
2314 rc = policydb_load_isids(&newpolicy->policydb, newpolicy->sidtab);
2315 if (rc) {
2316 pr_err("SELinux: unable to load the initial SIDs\n");
2317 goto err_mapping;
2318 }
2319
2320 if (!selinux_initialized(state)) {
2321 /* First policy load, so no need to preserve state from old policy */
2322 load_state->policy = newpolicy;
2323 load_state->convert_data = NULL;
2324 return 0;
2325 }
2326
2327 oldpolicy = rcu_dereference_protected(state->policy,
2328 lockdep_is_held(&state->policy_mutex));
2329
2330 /* Preserve active boolean values from the old policy */
2331 rc = security_preserve_bools(oldpolicy, newpolicy);
2332 if (rc) {
2333 pr_err("SELinux: unable to preserve booleans\n");
2334 goto err_free_isids;
2335 }
2336
2337 convert_data = kmalloc(sizeof(*convert_data), GFP_KERNEL);
2338 if (!convert_data) {
2339 rc = -ENOMEM;
2340 goto err_free_isids;
2341 }
2342
2343 /*
2344 * Convert the internal representations of contexts
2345 * in the new SID table.
2346 */
2347 convert_data->args.state = state;
2348 convert_data->args.oldp = &oldpolicy->policydb;
2349 convert_data->args.newp = &newpolicy->policydb;
2350
2351 convert_data->sidtab_params.func = convert_context;
2352 convert_data->sidtab_params.args = &convert_data->args;
2353 convert_data->sidtab_params.target = newpolicy->sidtab;
2354
2355 rc = sidtab_convert(oldpolicy->sidtab, &convert_data->sidtab_params);
2356 if (rc) {
2357 pr_err("SELinux: unable to convert the internal"
2358 " representation of contexts in the new SID"
2359 " table\n");
2360 goto err_free_convert_data;
2361 }
2362
2363 load_state->policy = newpolicy;
2364 load_state->convert_data = convert_data;
2365 return 0;
2366
2367 err_free_convert_data:
2368 kfree(convert_data);
2369 err_free_isids:
2370 sidtab_destroy(newpolicy->sidtab);
2371 err_mapping:
2372 kfree(newpolicy->map.mapping);
2373 err_policydb:
2374 policydb_destroy(&newpolicy->policydb);
2375 err_sidtab:
2376 kfree(newpolicy->sidtab);
2377 err_policy:
2378 kfree(newpolicy);
2379
2380 return rc;
2381 }
2382
2383 /**
2384 * ocontext_to_sid - Helper to safely get sid for an ocontext
2385 * @sidtab: SID table
2386 * @c: ocontext structure
2387 * @index: index of the context entry (0 or 1)
2388 * @out_sid: pointer to the resulting SID value
2389 *
2390 * For all ocontexts except OCON_ISID the SID fields are populated
2391 * on-demand when needed. Since updating the SID value is an SMP-sensitive
2392 * operation, this helper must be used to do that safely.
2393 *
2394 * WARNING: This function may return -ESTALE, indicating that the caller
2395 * must retry the operation after re-acquiring the policy pointer!
2396 */
ocontext_to_sid(struct sidtab * sidtab,struct ocontext * c,size_t index,u32 * out_sid)2397 static int ocontext_to_sid(struct sidtab *sidtab, struct ocontext *c,
2398 size_t index, u32 *out_sid)
2399 {
2400 int rc;
2401 u32 sid;
2402
2403 /* Ensure the associated sidtab entry is visible to this thread. */
2404 sid = smp_load_acquire(&c->sid[index]);
2405 if (!sid) {
2406 rc = sidtab_context_to_sid(sidtab, &c->context[index], &sid);
2407 if (rc)
2408 return rc;
2409
2410 /*
2411 * Ensure the new sidtab entry is visible to other threads
2412 * when they see the SID.
2413 */
2414 smp_store_release(&c->sid[index], sid);
2415 }
2416 *out_sid = sid;
2417 return 0;
2418 }
2419
2420 /**
2421 * security_port_sid - Obtain the SID for a port.
2422 * @state: SELinux state
2423 * @protocol: protocol number
2424 * @port: port number
2425 * @out_sid: security identifier
2426 */
security_port_sid(struct selinux_state * state,u8 protocol,u16 port,u32 * out_sid)2427 int security_port_sid(struct selinux_state *state,
2428 u8 protocol, u16 port, u32 *out_sid)
2429 {
2430 struct selinux_policy *policy;
2431 struct policydb *policydb;
2432 struct sidtab *sidtab;
2433 struct ocontext *c;
2434 int rc;
2435
2436 if (!selinux_initialized(state)) {
2437 *out_sid = SECINITSID_PORT;
2438 return 0;
2439 }
2440
2441 retry:
2442 rc = 0;
2443 rcu_read_lock();
2444 policy = rcu_dereference(state->policy);
2445 policydb = &policy->policydb;
2446 sidtab = policy->sidtab;
2447
2448 c = policydb->ocontexts[OCON_PORT];
2449 while (c) {
2450 if (c->u.port.protocol == protocol &&
2451 c->u.port.low_port <= port &&
2452 c->u.port.high_port >= port)
2453 break;
2454 c = c->next;
2455 }
2456
2457 if (c) {
2458 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2459 if (rc == -ESTALE) {
2460 rcu_read_unlock();
2461 goto retry;
2462 }
2463 if (rc)
2464 goto out;
2465 } else {
2466 *out_sid = SECINITSID_PORT;
2467 }
2468
2469 out:
2470 rcu_read_unlock();
2471 return rc;
2472 }
2473
2474 /**
2475 * security_ib_pkey_sid - Obtain the SID for a pkey.
2476 * @state: SELinux state
2477 * @subnet_prefix: Subnet Prefix
2478 * @pkey_num: pkey number
2479 * @out_sid: security identifier
2480 */
security_ib_pkey_sid(struct selinux_state * state,u64 subnet_prefix,u16 pkey_num,u32 * out_sid)2481 int security_ib_pkey_sid(struct selinux_state *state,
2482 u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
2483 {
2484 struct selinux_policy *policy;
2485 struct policydb *policydb;
2486 struct sidtab *sidtab;
2487 struct ocontext *c;
2488 int rc;
2489
2490 if (!selinux_initialized(state)) {
2491 *out_sid = SECINITSID_UNLABELED;
2492 return 0;
2493 }
2494
2495 retry:
2496 rc = 0;
2497 rcu_read_lock();
2498 policy = rcu_dereference(state->policy);
2499 policydb = &policy->policydb;
2500 sidtab = policy->sidtab;
2501
2502 c = policydb->ocontexts[OCON_IBPKEY];
2503 while (c) {
2504 if (c->u.ibpkey.low_pkey <= pkey_num &&
2505 c->u.ibpkey.high_pkey >= pkey_num &&
2506 c->u.ibpkey.subnet_prefix == subnet_prefix)
2507 break;
2508
2509 c = c->next;
2510 }
2511
2512 if (c) {
2513 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2514 if (rc == -ESTALE) {
2515 rcu_read_unlock();
2516 goto retry;
2517 }
2518 if (rc)
2519 goto out;
2520 } else
2521 *out_sid = SECINITSID_UNLABELED;
2522
2523 out:
2524 rcu_read_unlock();
2525 return rc;
2526 }
2527
2528 /**
2529 * security_ib_endport_sid - Obtain the SID for a subnet management interface.
2530 * @state: SELinux state
2531 * @dev_name: device name
2532 * @port_num: port number
2533 * @out_sid: security identifier
2534 */
security_ib_endport_sid(struct selinux_state * state,const char * dev_name,u8 port_num,u32 * out_sid)2535 int security_ib_endport_sid(struct selinux_state *state,
2536 const char *dev_name, u8 port_num, u32 *out_sid)
2537 {
2538 struct selinux_policy *policy;
2539 struct policydb *policydb;
2540 struct sidtab *sidtab;
2541 struct ocontext *c;
2542 int rc;
2543
2544 if (!selinux_initialized(state)) {
2545 *out_sid = SECINITSID_UNLABELED;
2546 return 0;
2547 }
2548
2549 retry:
2550 rc = 0;
2551 rcu_read_lock();
2552 policy = rcu_dereference(state->policy);
2553 policydb = &policy->policydb;
2554 sidtab = policy->sidtab;
2555
2556 c = policydb->ocontexts[OCON_IBENDPORT];
2557 while (c) {
2558 if (c->u.ibendport.port == port_num &&
2559 !strncmp(c->u.ibendport.dev_name,
2560 dev_name,
2561 IB_DEVICE_NAME_MAX))
2562 break;
2563
2564 c = c->next;
2565 }
2566
2567 if (c) {
2568 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2569 if (rc == -ESTALE) {
2570 rcu_read_unlock();
2571 goto retry;
2572 }
2573 if (rc)
2574 goto out;
2575 } else
2576 *out_sid = SECINITSID_UNLABELED;
2577
2578 out:
2579 rcu_read_unlock();
2580 return rc;
2581 }
2582
2583 /**
2584 * security_netif_sid - Obtain the SID for a network interface.
2585 * @state: SELinux state
2586 * @name: interface name
2587 * @if_sid: interface SID
2588 */
security_netif_sid(struct selinux_state * state,char * name,u32 * if_sid)2589 int security_netif_sid(struct selinux_state *state,
2590 char *name, u32 *if_sid)
2591 {
2592 struct selinux_policy *policy;
2593 struct policydb *policydb;
2594 struct sidtab *sidtab;
2595 int rc;
2596 struct ocontext *c;
2597
2598 if (!selinux_initialized(state)) {
2599 *if_sid = SECINITSID_NETIF;
2600 return 0;
2601 }
2602
2603 retry:
2604 rc = 0;
2605 rcu_read_lock();
2606 policy = rcu_dereference(state->policy);
2607 policydb = &policy->policydb;
2608 sidtab = policy->sidtab;
2609
2610 c = policydb->ocontexts[OCON_NETIF];
2611 while (c) {
2612 if (strcmp(name, c->u.name) == 0)
2613 break;
2614 c = c->next;
2615 }
2616
2617 if (c) {
2618 rc = ocontext_to_sid(sidtab, c, 0, if_sid);
2619 if (rc == -ESTALE) {
2620 rcu_read_unlock();
2621 goto retry;
2622 }
2623 if (rc)
2624 goto out;
2625 } else
2626 *if_sid = SECINITSID_NETIF;
2627
2628 out:
2629 rcu_read_unlock();
2630 return rc;
2631 }
2632
match_ipv6_addrmask(u32 * input,u32 * addr,u32 * mask)2633 static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask)
2634 {
2635 int i, fail = 0;
2636
2637 for (i = 0; i < 4; i++)
2638 if (addr[i] != (input[i] & mask[i])) {
2639 fail = 1;
2640 break;
2641 }
2642
2643 return !fail;
2644 }
2645
2646 /**
2647 * security_node_sid - Obtain the SID for a node (host).
2648 * @state: SELinux state
2649 * @domain: communication domain aka address family
2650 * @addrp: address
2651 * @addrlen: address length in bytes
2652 * @out_sid: security identifier
2653 */
security_node_sid(struct selinux_state * state,u16 domain,void * addrp,u32 addrlen,u32 * out_sid)2654 int security_node_sid(struct selinux_state *state,
2655 u16 domain,
2656 void *addrp,
2657 u32 addrlen,
2658 u32 *out_sid)
2659 {
2660 struct selinux_policy *policy;
2661 struct policydb *policydb;
2662 struct sidtab *sidtab;
2663 int rc;
2664 struct ocontext *c;
2665
2666 if (!selinux_initialized(state)) {
2667 *out_sid = SECINITSID_NODE;
2668 return 0;
2669 }
2670
2671 retry:
2672 rcu_read_lock();
2673 policy = rcu_dereference(state->policy);
2674 policydb = &policy->policydb;
2675 sidtab = policy->sidtab;
2676
2677 switch (domain) {
2678 case AF_INET: {
2679 u32 addr;
2680
2681 rc = -EINVAL;
2682 if (addrlen != sizeof(u32))
2683 goto out;
2684
2685 addr = *((u32 *)addrp);
2686
2687 c = policydb->ocontexts[OCON_NODE];
2688 while (c) {
2689 if (c->u.node.addr == (addr & c->u.node.mask))
2690 break;
2691 c = c->next;
2692 }
2693 break;
2694 }
2695
2696 case AF_INET6:
2697 rc = -EINVAL;
2698 if (addrlen != sizeof(u64) * 2)
2699 goto out;
2700 c = policydb->ocontexts[OCON_NODE6];
2701 while (c) {
2702 if (match_ipv6_addrmask(addrp, c->u.node6.addr,
2703 c->u.node6.mask))
2704 break;
2705 c = c->next;
2706 }
2707 break;
2708
2709 default:
2710 rc = 0;
2711 *out_sid = SECINITSID_NODE;
2712 goto out;
2713 }
2714
2715 if (c) {
2716 rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2717 if (rc == -ESTALE) {
2718 rcu_read_unlock();
2719 goto retry;
2720 }
2721 if (rc)
2722 goto out;
2723 } else {
2724 *out_sid = SECINITSID_NODE;
2725 }
2726
2727 rc = 0;
2728 out:
2729 rcu_read_unlock();
2730 return rc;
2731 }
2732
2733 #define SIDS_NEL 25
2734
2735 /**
2736 * security_get_user_sids - Obtain reachable SIDs for a user.
2737 * @state: SELinux state
2738 * @fromsid: starting SID
2739 * @username: username
2740 * @sids: array of reachable SIDs for user
2741 * @nel: number of elements in @sids
2742 *
2743 * Generate the set of SIDs for legal security contexts
2744 * for a given user that can be reached by @fromsid.
2745 * Set *@sids to point to a dynamically allocated
2746 * array containing the set of SIDs. Set *@nel to the
2747 * number of elements in the array.
2748 */
2749
security_get_user_sids(struct selinux_state * state,u32 fromsid,char * username,u32 ** sids,u32 * nel)2750 int security_get_user_sids(struct selinux_state *state,
2751 u32 fromsid,
2752 char *username,
2753 u32 **sids,
2754 u32 *nel)
2755 {
2756 struct selinux_policy *policy;
2757 struct policydb *policydb;
2758 struct sidtab *sidtab;
2759 struct context *fromcon, usercon;
2760 u32 *mysids = NULL, *mysids2, sid;
2761 u32 i, j, mynel, maxnel = SIDS_NEL;
2762 struct user_datum *user;
2763 struct role_datum *role;
2764 struct ebitmap_node *rnode, *tnode;
2765 int rc;
2766
2767 *sids = NULL;
2768 *nel = 0;
2769
2770 if (!selinux_initialized(state))
2771 return 0;
2772
2773 mysids = kcalloc(maxnel, sizeof(*mysids), GFP_KERNEL);
2774 if (!mysids)
2775 return -ENOMEM;
2776
2777 retry:
2778 mynel = 0;
2779 rcu_read_lock();
2780 policy = rcu_dereference(state->policy);
2781 policydb = &policy->policydb;
2782 sidtab = policy->sidtab;
2783
2784 context_init(&usercon);
2785
2786 rc = -EINVAL;
2787 fromcon = sidtab_search(sidtab, fromsid);
2788 if (!fromcon)
2789 goto out_unlock;
2790
2791 rc = -EINVAL;
2792 user = symtab_search(&policydb->p_users, username);
2793 if (!user)
2794 goto out_unlock;
2795
2796 usercon.user = user->value;
2797
2798 ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
2799 role = policydb->role_val_to_struct[i];
2800 usercon.role = i + 1;
2801 ebitmap_for_each_positive_bit(&role->types, tnode, j) {
2802 usercon.type = j + 1;
2803
2804 if (mls_setup_user_range(policydb, fromcon, user,
2805 &usercon))
2806 continue;
2807
2808 rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
2809 if (rc == -ESTALE) {
2810 rcu_read_unlock();
2811 goto retry;
2812 }
2813 if (rc)
2814 goto out_unlock;
2815 if (mynel < maxnel) {
2816 mysids[mynel++] = sid;
2817 } else {
2818 rc = -ENOMEM;
2819 maxnel += SIDS_NEL;
2820 mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
2821 if (!mysids2)
2822 goto out_unlock;
2823 memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
2824 kfree(mysids);
2825 mysids = mysids2;
2826 mysids[mynel++] = sid;
2827 }
2828 }
2829 }
2830 rc = 0;
2831 out_unlock:
2832 rcu_read_unlock();
2833 if (rc || !mynel) {
2834 kfree(mysids);
2835 return rc;
2836 }
2837
2838 rc = -ENOMEM;
2839 mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
2840 if (!mysids2) {
2841 kfree(mysids);
2842 return rc;
2843 }
2844 for (i = 0, j = 0; i < mynel; i++) {
2845 struct av_decision dummy_avd;
2846 rc = avc_has_perm_noaudit(state,
2847 fromsid, mysids[i],
2848 SECCLASS_PROCESS, /* kernel value */
2849 PROCESS__TRANSITION, AVC_STRICT,
2850 &dummy_avd);
2851 if (!rc)
2852 mysids2[j++] = mysids[i];
2853 cond_resched();
2854 }
2855 kfree(mysids);
2856 *sids = mysids2;
2857 *nel = j;
2858 return 0;
2859 }
2860
2861 /**
2862 * __security_genfs_sid - Helper to obtain a SID for a file in a filesystem
2863 * @policy: policy
2864 * @fstype: filesystem type
2865 * @path: path from root of mount
2866 * @orig_sclass: file security class
2867 * @sid: SID for path
2868 *
2869 * Obtain a SID to use for a file in a filesystem that
2870 * cannot support xattr or use a fixed labeling behavior like
2871 * transition SIDs or task SIDs.
2872 *
2873 * WARNING: This function may return -ESTALE, indicating that the caller
2874 * must retry the operation after re-acquiring the policy pointer!
2875 */
__security_genfs_sid(struct selinux_policy * policy,const char * fstype,char * path,u16 orig_sclass,u32 * sid)2876 static inline int __security_genfs_sid(struct selinux_policy *policy,
2877 const char *fstype,
2878 char *path,
2879 u16 orig_sclass,
2880 u32 *sid)
2881 {
2882 struct policydb *policydb = &policy->policydb;
2883 struct sidtab *sidtab = policy->sidtab;
2884 int len;
2885 u16 sclass;
2886 struct genfs *genfs;
2887 struct ocontext *c;
2888 int cmp = 0;
2889
2890 while (path[0] == '/' && path[1] == '/')
2891 path++;
2892
2893 sclass = unmap_class(&policy->map, orig_sclass);
2894 *sid = SECINITSID_UNLABELED;
2895
2896 for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
2897 cmp = strcmp(fstype, genfs->fstype);
2898 if (cmp <= 0)
2899 break;
2900 }
2901
2902 if (!genfs || cmp)
2903 return -ENOENT;
2904
2905 for (c = genfs->head; c; c = c->next) {
2906 len = strlen(c->u.name);
2907 if ((!c->v.sclass || sclass == c->v.sclass) &&
2908 (strncmp(c->u.name, path, len) == 0))
2909 break;
2910 }
2911
2912 if (!c)
2913 return -ENOENT;
2914
2915 return ocontext_to_sid(sidtab, c, 0, sid);
2916 }
2917
2918 /**
2919 * security_genfs_sid - Obtain a SID for a file in a filesystem
2920 * @state: SELinux state
2921 * @fstype: filesystem type
2922 * @path: path from root of mount
2923 * @orig_sclass: file security class
2924 * @sid: SID for path
2925 *
2926 * Acquire policy_rwlock before calling __security_genfs_sid() and release
2927 * it afterward.
2928 */
security_genfs_sid(struct selinux_state * state,const char * fstype,char * path,u16 orig_sclass,u32 * sid)2929 int security_genfs_sid(struct selinux_state *state,
2930 const char *fstype,
2931 char *path,
2932 u16 orig_sclass,
2933 u32 *sid)
2934 {
2935 struct selinux_policy *policy;
2936 int retval;
2937
2938 if (!selinux_initialized(state)) {
2939 *sid = SECINITSID_UNLABELED;
2940 return 0;
2941 }
2942
2943 do {
2944 rcu_read_lock();
2945 policy = rcu_dereference(state->policy);
2946 retval = __security_genfs_sid(policy, fstype, path,
2947 orig_sclass, sid);
2948 rcu_read_unlock();
2949 } while (retval == -ESTALE);
2950 return retval;
2951 }
2952
selinux_policy_genfs_sid(struct selinux_policy * policy,const char * fstype,char * path,u16 orig_sclass,u32 * sid)2953 int selinux_policy_genfs_sid(struct selinux_policy *policy,
2954 const char *fstype,
2955 char *path,
2956 u16 orig_sclass,
2957 u32 *sid)
2958 {
2959 /* no lock required, policy is not yet accessible by other threads */
2960 return __security_genfs_sid(policy, fstype, path, orig_sclass, sid);
2961 }
2962
2963 /**
2964 * security_fs_use - Determine how to handle labeling for a filesystem.
2965 * @state: SELinux state
2966 * @sb: superblock in question
2967 */
security_fs_use(struct selinux_state * state,struct super_block * sb)2968 int security_fs_use(struct selinux_state *state, struct super_block *sb)
2969 {
2970 struct selinux_policy *policy;
2971 struct policydb *policydb;
2972 struct sidtab *sidtab;
2973 int rc;
2974 struct ocontext *c;
2975 struct superblock_security_struct *sbsec = selinux_superblock(sb);
2976 const char *fstype = sb->s_type->name;
2977
2978 if (!selinux_initialized(state)) {
2979 sbsec->behavior = SECURITY_FS_USE_NONE;
2980 sbsec->sid = SECINITSID_UNLABELED;
2981 return 0;
2982 }
2983
2984 retry:
2985 rc = 0;
2986 rcu_read_lock();
2987 policy = rcu_dereference(state->policy);
2988 policydb = &policy->policydb;
2989 sidtab = policy->sidtab;
2990
2991 c = policydb->ocontexts[OCON_FSUSE];
2992 while (c) {
2993 if (strcmp(fstype, c->u.name) == 0)
2994 break;
2995 c = c->next;
2996 }
2997
2998 if (c) {
2999 sbsec->behavior = c->v.behavior;
3000 rc = ocontext_to_sid(sidtab, c, 0, &sbsec->sid);
3001 if (rc == -ESTALE) {
3002 rcu_read_unlock();
3003 goto retry;
3004 }
3005 if (rc)
3006 goto out;
3007 } else {
3008 rc = __security_genfs_sid(policy, fstype, "/",
3009 SECCLASS_DIR, &sbsec->sid);
3010 if (rc == -ESTALE) {
3011 rcu_read_unlock();
3012 goto retry;
3013 }
3014 if (rc) {
3015 sbsec->behavior = SECURITY_FS_USE_NONE;
3016 rc = 0;
3017 } else {
3018 sbsec->behavior = SECURITY_FS_USE_GENFS;
3019 }
3020 }
3021
3022 out:
3023 rcu_read_unlock();
3024 return rc;
3025 }
3026
security_get_bools(struct selinux_policy * policy,u32 * len,char *** names,int ** values)3027 int security_get_bools(struct selinux_policy *policy,
3028 u32 *len, char ***names, int **values)
3029 {
3030 struct policydb *policydb;
3031 u32 i;
3032 int rc;
3033
3034 policydb = &policy->policydb;
3035
3036 *names = NULL;
3037 *values = NULL;
3038
3039 rc = 0;
3040 *len = policydb->p_bools.nprim;
3041 if (!*len)
3042 goto out;
3043
3044 rc = -ENOMEM;
3045 *names = kcalloc(*len, sizeof(char *), GFP_ATOMIC);
3046 if (!*names)
3047 goto err;
3048
3049 rc = -ENOMEM;
3050 *values = kcalloc(*len, sizeof(int), GFP_ATOMIC);
3051 if (!*values)
3052 goto err;
3053
3054 for (i = 0; i < *len; i++) {
3055 (*values)[i] = policydb->bool_val_to_struct[i]->state;
3056
3057 rc = -ENOMEM;
3058 (*names)[i] = kstrdup(sym_name(policydb, SYM_BOOLS, i),
3059 GFP_ATOMIC);
3060 if (!(*names)[i])
3061 goto err;
3062 }
3063 rc = 0;
3064 out:
3065 return rc;
3066 err:
3067 if (*names) {
3068 for (i = 0; i < *len; i++)
3069 kfree((*names)[i]);
3070 kfree(*names);
3071 }
3072 kfree(*values);
3073 *len = 0;
3074 *names = NULL;
3075 *values = NULL;
3076 goto out;
3077 }
3078
3079
security_set_bools(struct selinux_state * state,u32 len,int * values)3080 int security_set_bools(struct selinux_state *state, u32 len, int *values)
3081 {
3082 struct selinux_policy *newpolicy, *oldpolicy;
3083 int rc;
3084 u32 i, seqno = 0;
3085
3086 if (!selinux_initialized(state))
3087 return -EINVAL;
3088
3089 oldpolicy = rcu_dereference_protected(state->policy,
3090 lockdep_is_held(&state->policy_mutex));
3091
3092 /* Consistency check on number of booleans, should never fail */
3093 if (WARN_ON(len != oldpolicy->policydb.p_bools.nprim))
3094 return -EINVAL;
3095
3096 newpolicy = kmemdup(oldpolicy, sizeof(*newpolicy), GFP_KERNEL);
3097 if (!newpolicy)
3098 return -ENOMEM;
3099
3100 /*
3101 * Deep copy only the parts of the policydb that might be
3102 * modified as a result of changing booleans.
3103 */
3104 rc = cond_policydb_dup(&newpolicy->policydb, &oldpolicy->policydb);
3105 if (rc) {
3106 kfree(newpolicy);
3107 return -ENOMEM;
3108 }
3109
3110 /* Update the boolean states in the copy */
3111 for (i = 0; i < len; i++) {
3112 int new_state = !!values[i];
3113 int old_state = newpolicy->policydb.bool_val_to_struct[i]->state;
3114
3115 if (new_state != old_state) {
3116 audit_log(audit_context(), GFP_ATOMIC,
3117 AUDIT_MAC_CONFIG_CHANGE,
3118 "bool=%s val=%d old_val=%d auid=%u ses=%u",
3119 sym_name(&newpolicy->policydb, SYM_BOOLS, i),
3120 new_state,
3121 old_state,
3122 from_kuid(&init_user_ns, audit_get_loginuid(current)),
3123 audit_get_sessionid(current));
3124 newpolicy->policydb.bool_val_to_struct[i]->state = new_state;
3125 }
3126 }
3127
3128 /* Re-evaluate the conditional rules in the copy */
3129 evaluate_cond_nodes(&newpolicy->policydb);
3130
3131 /* Set latest granting seqno for new policy */
3132 newpolicy->latest_granting = oldpolicy->latest_granting + 1;
3133 seqno = newpolicy->latest_granting;
3134
3135 /* Install the new policy */
3136 rcu_assign_pointer(state->policy, newpolicy);
3137
3138 /*
3139 * Free the conditional portions of the old policydb
3140 * that were copied for the new policy, and the oldpolicy
3141 * structure itself but not what it references.
3142 */
3143 synchronize_rcu();
3144 selinux_policy_cond_free(oldpolicy);
3145
3146 /* Notify others of the policy change */
3147 selinux_notify_policy_change(state, seqno);
3148 return 0;
3149 }
3150
security_get_bool_value(struct selinux_state * state,u32 index)3151 int security_get_bool_value(struct selinux_state *state,
3152 u32 index)
3153 {
3154 struct selinux_policy *policy;
3155 struct policydb *policydb;
3156 int rc;
3157 u32 len;
3158
3159 if (!selinux_initialized(state))
3160 return 0;
3161
3162 rcu_read_lock();
3163 policy = rcu_dereference(state->policy);
3164 policydb = &policy->policydb;
3165
3166 rc = -EFAULT;
3167 len = policydb->p_bools.nprim;
3168 if (index >= len)
3169 goto out;
3170
3171 rc = policydb->bool_val_to_struct[index]->state;
3172 out:
3173 rcu_read_unlock();
3174 return rc;
3175 }
3176
security_preserve_bools(struct selinux_policy * oldpolicy,struct selinux_policy * newpolicy)3177 static int security_preserve_bools(struct selinux_policy *oldpolicy,
3178 struct selinux_policy *newpolicy)
3179 {
3180 int rc, *bvalues = NULL;
3181 char **bnames = NULL;
3182 struct cond_bool_datum *booldatum;
3183 u32 i, nbools = 0;
3184
3185 rc = security_get_bools(oldpolicy, &nbools, &bnames, &bvalues);
3186 if (rc)
3187 goto out;
3188 for (i = 0; i < nbools; i++) {
3189 booldatum = symtab_search(&newpolicy->policydb.p_bools,
3190 bnames[i]);
3191 if (booldatum)
3192 booldatum->state = bvalues[i];
3193 }
3194 evaluate_cond_nodes(&newpolicy->policydb);
3195
3196 out:
3197 if (bnames) {
3198 for (i = 0; i < nbools; i++)
3199 kfree(bnames[i]);
3200 }
3201 kfree(bnames);
3202 kfree(bvalues);
3203 return rc;
3204 }
3205
3206 /*
3207 * security_sid_mls_copy() - computes a new sid based on the given
3208 * sid and the mls portion of mls_sid.
3209 */
security_sid_mls_copy(struct selinux_state * state,u32 sid,u32 mls_sid,u32 * new_sid)3210 int security_sid_mls_copy(struct selinux_state *state,
3211 u32 sid, u32 mls_sid, u32 *new_sid)
3212 {
3213 struct selinux_policy *policy;
3214 struct policydb *policydb;
3215 struct sidtab *sidtab;
3216 struct context *context1;
3217 struct context *context2;
3218 struct context newcon;
3219 char *s;
3220 u32 len;
3221 int rc;
3222
3223 if (!selinux_initialized(state)) {
3224 *new_sid = sid;
3225 return 0;
3226 }
3227
3228 retry:
3229 rc = 0;
3230 context_init(&newcon);
3231
3232 rcu_read_lock();
3233 policy = rcu_dereference(state->policy);
3234 policydb = &policy->policydb;
3235 sidtab = policy->sidtab;
3236
3237 if (!policydb->mls_enabled) {
3238 *new_sid = sid;
3239 goto out_unlock;
3240 }
3241
3242 rc = -EINVAL;
3243 context1 = sidtab_search(sidtab, sid);
3244 if (!context1) {
3245 pr_err("SELinux: %s: unrecognized SID %d\n",
3246 __func__, sid);
3247 goto out_unlock;
3248 }
3249
3250 rc = -EINVAL;
3251 context2 = sidtab_search(sidtab, mls_sid);
3252 if (!context2) {
3253 pr_err("SELinux: %s: unrecognized SID %d\n",
3254 __func__, mls_sid);
3255 goto out_unlock;
3256 }
3257
3258 newcon.user = context1->user;
3259 newcon.role = context1->role;
3260 newcon.type = context1->type;
3261 rc = mls_context_cpy(&newcon, context2);
3262 if (rc)
3263 goto out_unlock;
3264
3265 /* Check the validity of the new context. */
3266 if (!policydb_context_isvalid(policydb, &newcon)) {
3267 rc = convert_context_handle_invalid_context(state, policydb,
3268 &newcon);
3269 if (rc) {
3270 if (!context_struct_to_string(policydb, &newcon, &s,
3271 &len)) {
3272 struct audit_buffer *ab;
3273
3274 ab = audit_log_start(audit_context(),
3275 GFP_ATOMIC,
3276 AUDIT_SELINUX_ERR);
3277 audit_log_format(ab,
3278 "op=security_sid_mls_copy invalid_context=");
3279 /* don't record NUL with untrusted strings */
3280 audit_log_n_untrustedstring(ab, s, len - 1);
3281 audit_log_end(ab);
3282 kfree(s);
3283 }
3284 goto out_unlock;
3285 }
3286 }
3287 rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
3288 if (rc == -ESTALE) {
3289 rcu_read_unlock();
3290 context_destroy(&newcon);
3291 goto retry;
3292 }
3293 out_unlock:
3294 rcu_read_unlock();
3295 context_destroy(&newcon);
3296 return rc;
3297 }
3298
3299 /**
3300 * security_net_peersid_resolve - Compare and resolve two network peer SIDs
3301 * @state: SELinux state
3302 * @nlbl_sid: NetLabel SID
3303 * @nlbl_type: NetLabel labeling protocol type
3304 * @xfrm_sid: XFRM SID
3305 * @peer_sid: network peer sid
3306 *
3307 * Description:
3308 * Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be
3309 * resolved into a single SID it is returned via @peer_sid and the function
3310 * returns zero. Otherwise @peer_sid is set to SECSID_NULL and the function
3311 * returns a negative value. A table summarizing the behavior is below:
3312 *
3313 * | function return | @sid
3314 * ------------------------------+-----------------+-----------------
3315 * no peer labels | 0 | SECSID_NULL
3316 * single peer label | 0 | <peer_label>
3317 * multiple, consistent labels | 0 | <peer_label>
3318 * multiple, inconsistent labels | -<errno> | SECSID_NULL
3319 *
3320 */
security_net_peersid_resolve(struct selinux_state * state,u32 nlbl_sid,u32 nlbl_type,u32 xfrm_sid,u32 * peer_sid)3321 int security_net_peersid_resolve(struct selinux_state *state,
3322 u32 nlbl_sid, u32 nlbl_type,
3323 u32 xfrm_sid,
3324 u32 *peer_sid)
3325 {
3326 struct selinux_policy *policy;
3327 struct policydb *policydb;
3328 struct sidtab *sidtab;
3329 int rc;
3330 struct context *nlbl_ctx;
3331 struct context *xfrm_ctx;
3332
3333 *peer_sid = SECSID_NULL;
3334
3335 /* handle the common (which also happens to be the set of easy) cases
3336 * right away, these two if statements catch everything involving a
3337 * single or absent peer SID/label */
3338 if (xfrm_sid == SECSID_NULL) {
3339 *peer_sid = nlbl_sid;
3340 return 0;
3341 }
3342 /* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label
3343 * and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label
3344 * is present */
3345 if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) {
3346 *peer_sid = xfrm_sid;
3347 return 0;
3348 }
3349
3350 if (!selinux_initialized(state))
3351 return 0;
3352
3353 rcu_read_lock();
3354 policy = rcu_dereference(state->policy);
3355 policydb = &policy->policydb;
3356 sidtab = policy->sidtab;
3357
3358 /*
3359 * We don't need to check initialized here since the only way both
3360 * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
3361 * security server was initialized and state->initialized was true.
3362 */
3363 if (!policydb->mls_enabled) {
3364 rc = 0;
3365 goto out;
3366 }
3367
3368 rc = -EINVAL;
3369 nlbl_ctx = sidtab_search(sidtab, nlbl_sid);
3370 if (!nlbl_ctx) {
3371 pr_err("SELinux: %s: unrecognized SID %d\n",
3372 __func__, nlbl_sid);
3373 goto out;
3374 }
3375 rc = -EINVAL;
3376 xfrm_ctx = sidtab_search(sidtab, xfrm_sid);
3377 if (!xfrm_ctx) {
3378 pr_err("SELinux: %s: unrecognized SID %d\n",
3379 __func__, xfrm_sid);
3380 goto out;
3381 }
3382 rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES);
3383 if (rc)
3384 goto out;
3385
3386 /* at present NetLabel SIDs/labels really only carry MLS
3387 * information so if the MLS portion of the NetLabel SID
3388 * matches the MLS portion of the labeled XFRM SID/label
3389 * then pass along the XFRM SID as it is the most
3390 * expressive */
3391 *peer_sid = xfrm_sid;
3392 out:
3393 rcu_read_unlock();
3394 return rc;
3395 }
3396
get_classes_callback(void * k,void * d,void * args)3397 static int get_classes_callback(void *k, void *d, void *args)
3398 {
3399 struct class_datum *datum = d;
3400 char *name = k, **classes = args;
3401 int value = datum->value - 1;
3402
3403 classes[value] = kstrdup(name, GFP_ATOMIC);
3404 if (!classes[value])
3405 return -ENOMEM;
3406
3407 return 0;
3408 }
3409
security_get_classes(struct selinux_policy * policy,char *** classes,int * nclasses)3410 int security_get_classes(struct selinux_policy *policy,
3411 char ***classes, int *nclasses)
3412 {
3413 struct policydb *policydb;
3414 int rc;
3415
3416 policydb = &policy->policydb;
3417
3418 rc = -ENOMEM;
3419 *nclasses = policydb->p_classes.nprim;
3420 *classes = kcalloc(*nclasses, sizeof(**classes), GFP_ATOMIC);
3421 if (!*classes)
3422 goto out;
3423
3424 rc = hashtab_map(&policydb->p_classes.table, get_classes_callback,
3425 *classes);
3426 if (rc) {
3427 int i;
3428 for (i = 0; i < *nclasses; i++)
3429 kfree((*classes)[i]);
3430 kfree(*classes);
3431 }
3432
3433 out:
3434 return rc;
3435 }
3436
get_permissions_callback(void * k,void * d,void * args)3437 static int get_permissions_callback(void *k, void *d, void *args)
3438 {
3439 struct perm_datum *datum = d;
3440 char *name = k, **perms = args;
3441 int value = datum->value - 1;
3442
3443 perms[value] = kstrdup(name, GFP_ATOMIC);
3444 if (!perms[value])
3445 return -ENOMEM;
3446
3447 return 0;
3448 }
3449
security_get_permissions(struct selinux_policy * policy,char * class,char *** perms,int * nperms)3450 int security_get_permissions(struct selinux_policy *policy,
3451 char *class, char ***perms, int *nperms)
3452 {
3453 struct policydb *policydb;
3454 int rc, i;
3455 struct class_datum *match;
3456
3457 policydb = &policy->policydb;
3458
3459 rc = -EINVAL;
3460 match = symtab_search(&policydb->p_classes, class);
3461 if (!match) {
3462 pr_err("SELinux: %s: unrecognized class %s\n",
3463 __func__, class);
3464 goto out;
3465 }
3466
3467 rc = -ENOMEM;
3468 *nperms = match->permissions.nprim;
3469 *perms = kcalloc(*nperms, sizeof(**perms), GFP_ATOMIC);
3470 if (!*perms)
3471 goto out;
3472
3473 if (match->comdatum) {
3474 rc = hashtab_map(&match->comdatum->permissions.table,
3475 get_permissions_callback, *perms);
3476 if (rc)
3477 goto err;
3478 }
3479
3480 rc = hashtab_map(&match->permissions.table, get_permissions_callback,
3481 *perms);
3482 if (rc)
3483 goto err;
3484
3485 out:
3486 return rc;
3487
3488 err:
3489 for (i = 0; i < *nperms; i++)
3490 kfree((*perms)[i]);
3491 kfree(*perms);
3492 return rc;
3493 }
3494
security_get_reject_unknown(struct selinux_state * state)3495 int security_get_reject_unknown(struct selinux_state *state)
3496 {
3497 struct selinux_policy *policy;
3498 int value;
3499
3500 if (!selinux_initialized(state))
3501 return 0;
3502
3503 rcu_read_lock();
3504 policy = rcu_dereference(state->policy);
3505 value = policy->policydb.reject_unknown;
3506 rcu_read_unlock();
3507 return value;
3508 }
3509
security_get_allow_unknown(struct selinux_state * state)3510 int security_get_allow_unknown(struct selinux_state *state)
3511 {
3512 struct selinux_policy *policy;
3513 int value;
3514
3515 if (!selinux_initialized(state))
3516 return 0;
3517
3518 rcu_read_lock();
3519 policy = rcu_dereference(state->policy);
3520 value = policy->policydb.allow_unknown;
3521 rcu_read_unlock();
3522 return value;
3523 }
3524
3525 /**
3526 * security_policycap_supported - Check for a specific policy capability
3527 * @state: SELinux state
3528 * @req_cap: capability
3529 *
3530 * Description:
3531 * This function queries the currently loaded policy to see if it supports the
3532 * capability specified by @req_cap. Returns true (1) if the capability is
3533 * supported, false (0) if it isn't supported.
3534 *
3535 */
security_policycap_supported(struct selinux_state * state,unsigned int req_cap)3536 int security_policycap_supported(struct selinux_state *state,
3537 unsigned int req_cap)
3538 {
3539 struct selinux_policy *policy;
3540 int rc;
3541
3542 if (!selinux_initialized(state))
3543 return 0;
3544
3545 rcu_read_lock();
3546 policy = rcu_dereference(state->policy);
3547 rc = ebitmap_get_bit(&policy->policydb.policycaps, req_cap);
3548 rcu_read_unlock();
3549
3550 return rc;
3551 }
3552
3553 struct selinux_audit_rule {
3554 u32 au_seqno;
3555 struct context au_ctxt;
3556 };
3557
selinux_audit_rule_free(void * vrule)3558 void selinux_audit_rule_free(void *vrule)
3559 {
3560 struct selinux_audit_rule *rule = vrule;
3561
3562 if (rule) {
3563 context_destroy(&rule->au_ctxt);
3564 kfree(rule);
3565 }
3566 }
3567
selinux_audit_rule_init(u32 field,u32 op,char * rulestr,void ** vrule)3568 int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
3569 {
3570 struct selinux_state *state = &selinux_state;
3571 struct selinux_policy *policy;
3572 struct policydb *policydb;
3573 struct selinux_audit_rule *tmprule;
3574 struct role_datum *roledatum;
3575 struct type_datum *typedatum;
3576 struct user_datum *userdatum;
3577 struct selinux_audit_rule **rule = (struct selinux_audit_rule **)vrule;
3578 int rc = 0;
3579
3580 *rule = NULL;
3581
3582 if (!selinux_initialized(state))
3583 return -EOPNOTSUPP;
3584
3585 switch (field) {
3586 case AUDIT_SUBJ_USER:
3587 case AUDIT_SUBJ_ROLE:
3588 case AUDIT_SUBJ_TYPE:
3589 case AUDIT_OBJ_USER:
3590 case AUDIT_OBJ_ROLE:
3591 case AUDIT_OBJ_TYPE:
3592 /* only 'equals' and 'not equals' fit user, role, and type */
3593 if (op != Audit_equal && op != Audit_not_equal)
3594 return -EINVAL;
3595 break;
3596 case AUDIT_SUBJ_SEN:
3597 case AUDIT_SUBJ_CLR:
3598 case AUDIT_OBJ_LEV_LOW:
3599 case AUDIT_OBJ_LEV_HIGH:
3600 /* we do not allow a range, indicated by the presence of '-' */
3601 if (strchr(rulestr, '-'))
3602 return -EINVAL;
3603 break;
3604 default:
3605 /* only the above fields are valid */
3606 return -EINVAL;
3607 }
3608
3609 tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
3610 if (!tmprule)
3611 return -ENOMEM;
3612
3613 context_init(&tmprule->au_ctxt);
3614
3615 rcu_read_lock();
3616 policy = rcu_dereference(state->policy);
3617 policydb = &policy->policydb;
3618
3619 tmprule->au_seqno = policy->latest_granting;
3620
3621 switch (field) {
3622 case AUDIT_SUBJ_USER:
3623 case AUDIT_OBJ_USER:
3624 rc = -EINVAL;
3625 userdatum = symtab_search(&policydb->p_users, rulestr);
3626 if (!userdatum)
3627 goto out;
3628 tmprule->au_ctxt.user = userdatum->value;
3629 break;
3630 case AUDIT_SUBJ_ROLE:
3631 case AUDIT_OBJ_ROLE:
3632 rc = -EINVAL;
3633 roledatum = symtab_search(&policydb->p_roles, rulestr);
3634 if (!roledatum)
3635 goto out;
3636 tmprule->au_ctxt.role = roledatum->value;
3637 break;
3638 case AUDIT_SUBJ_TYPE:
3639 case AUDIT_OBJ_TYPE:
3640 rc = -EINVAL;
3641 typedatum = symtab_search(&policydb->p_types, rulestr);
3642 if (!typedatum)
3643 goto out;
3644 tmprule->au_ctxt.type = typedatum->value;
3645 break;
3646 case AUDIT_SUBJ_SEN:
3647 case AUDIT_SUBJ_CLR:
3648 case AUDIT_OBJ_LEV_LOW:
3649 case AUDIT_OBJ_LEV_HIGH:
3650 rc = mls_from_string(policydb, rulestr, &tmprule->au_ctxt,
3651 GFP_ATOMIC);
3652 if (rc)
3653 goto out;
3654 break;
3655 }
3656 rc = 0;
3657 out:
3658 rcu_read_unlock();
3659
3660 if (rc) {
3661 selinux_audit_rule_free(tmprule);
3662 tmprule = NULL;
3663 }
3664
3665 *rule = tmprule;
3666
3667 return rc;
3668 }
3669
3670 /* Check to see if the rule contains any selinux fields */
selinux_audit_rule_known(struct audit_krule * rule)3671 int selinux_audit_rule_known(struct audit_krule *rule)
3672 {
3673 int i;
3674
3675 for (i = 0; i < rule->field_count; i++) {
3676 struct audit_field *f = &rule->fields[i];
3677 switch (f->type) {
3678 case AUDIT_SUBJ_USER:
3679 case AUDIT_SUBJ_ROLE:
3680 case AUDIT_SUBJ_TYPE:
3681 case AUDIT_SUBJ_SEN:
3682 case AUDIT_SUBJ_CLR:
3683 case AUDIT_OBJ_USER:
3684 case AUDIT_OBJ_ROLE:
3685 case AUDIT_OBJ_TYPE:
3686 case AUDIT_OBJ_LEV_LOW:
3687 case AUDIT_OBJ_LEV_HIGH:
3688 return 1;
3689 }
3690 }
3691
3692 return 0;
3693 }
3694
selinux_audit_rule_match(u32 sid,u32 field,u32 op,void * vrule)3695 int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
3696 {
3697 struct selinux_state *state = &selinux_state;
3698 struct selinux_policy *policy;
3699 struct context *ctxt;
3700 struct mls_level *level;
3701 struct selinux_audit_rule *rule = vrule;
3702 int match = 0;
3703
3704 if (unlikely(!rule)) {
3705 WARN_ONCE(1, "selinux_audit_rule_match: missing rule\n");
3706 return -ENOENT;
3707 }
3708
3709 if (!selinux_initialized(state))
3710 return 0;
3711
3712 rcu_read_lock();
3713
3714 policy = rcu_dereference(state->policy);
3715
3716 if (rule->au_seqno < policy->latest_granting) {
3717 match = -ESTALE;
3718 goto out;
3719 }
3720
3721 ctxt = sidtab_search(policy->sidtab, sid);
3722 if (unlikely(!ctxt)) {
3723 WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
3724 sid);
3725 match = -ENOENT;
3726 goto out;
3727 }
3728
3729 /* a field/op pair that is not caught here will simply fall through
3730 without a match */
3731 switch (field) {
3732 case AUDIT_SUBJ_USER:
3733 case AUDIT_OBJ_USER:
3734 switch (op) {
3735 case Audit_equal:
3736 match = (ctxt->user == rule->au_ctxt.user);
3737 break;
3738 case Audit_not_equal:
3739 match = (ctxt->user != rule->au_ctxt.user);
3740 break;
3741 }
3742 break;
3743 case AUDIT_SUBJ_ROLE:
3744 case AUDIT_OBJ_ROLE:
3745 switch (op) {
3746 case Audit_equal:
3747 match = (ctxt->role == rule->au_ctxt.role);
3748 break;
3749 case Audit_not_equal:
3750 match = (ctxt->role != rule->au_ctxt.role);
3751 break;
3752 }
3753 break;
3754 case AUDIT_SUBJ_TYPE:
3755 case AUDIT_OBJ_TYPE:
3756 switch (op) {
3757 case Audit_equal:
3758 match = (ctxt->type == rule->au_ctxt.type);
3759 break;
3760 case Audit_not_equal:
3761 match = (ctxt->type != rule->au_ctxt.type);
3762 break;
3763 }
3764 break;
3765 case AUDIT_SUBJ_SEN:
3766 case AUDIT_SUBJ_CLR:
3767 case AUDIT_OBJ_LEV_LOW:
3768 case AUDIT_OBJ_LEV_HIGH:
3769 level = ((field == AUDIT_SUBJ_SEN ||
3770 field == AUDIT_OBJ_LEV_LOW) ?
3771 &ctxt->range.level[0] : &ctxt->range.level[1]);
3772 switch (op) {
3773 case Audit_equal:
3774 match = mls_level_eq(&rule->au_ctxt.range.level[0],
3775 level);
3776 break;
3777 case Audit_not_equal:
3778 match = !mls_level_eq(&rule->au_ctxt.range.level[0],
3779 level);
3780 break;
3781 case Audit_lt:
3782 match = (mls_level_dom(&rule->au_ctxt.range.level[0],
3783 level) &&
3784 !mls_level_eq(&rule->au_ctxt.range.level[0],
3785 level));
3786 break;
3787 case Audit_le:
3788 match = mls_level_dom(&rule->au_ctxt.range.level[0],
3789 level);
3790 break;
3791 case Audit_gt:
3792 match = (mls_level_dom(level,
3793 &rule->au_ctxt.range.level[0]) &&
3794 !mls_level_eq(level,
3795 &rule->au_ctxt.range.level[0]));
3796 break;
3797 case Audit_ge:
3798 match = mls_level_dom(level,
3799 &rule->au_ctxt.range.level[0]);
3800 break;
3801 }
3802 }
3803
3804 out:
3805 rcu_read_unlock();
3806 return match;
3807 }
3808
aurule_avc_callback(u32 event)3809 static int aurule_avc_callback(u32 event)
3810 {
3811 if (event == AVC_CALLBACK_RESET)
3812 return audit_update_lsm_rules();
3813 return 0;
3814 }
3815
aurule_init(void)3816 static int __init aurule_init(void)
3817 {
3818 int err;
3819
3820 err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET);
3821 if (err)
3822 panic("avc_add_callback() failed, error %d\n", err);
3823
3824 return err;
3825 }
3826 __initcall(aurule_init);
3827
3828 #ifdef CONFIG_NETLABEL
3829 /**
3830 * security_netlbl_cache_add - Add an entry to the NetLabel cache
3831 * @secattr: the NetLabel packet security attributes
3832 * @sid: the SELinux SID
3833 *
3834 * Description:
3835 * Attempt to cache the context in @ctx, which was derived from the packet in
3836 * @skb, in the NetLabel subsystem cache. This function assumes @secattr has
3837 * already been initialized.
3838 *
3839 */
security_netlbl_cache_add(struct netlbl_lsm_secattr * secattr,u32 sid)3840 static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
3841 u32 sid)
3842 {
3843 u32 *sid_cache;
3844
3845 sid_cache = kmalloc(sizeof(*sid_cache), GFP_ATOMIC);
3846 if (sid_cache == NULL)
3847 return;
3848 secattr->cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
3849 if (secattr->cache == NULL) {
3850 kfree(sid_cache);
3851 return;
3852 }
3853
3854 *sid_cache = sid;
3855 secattr->cache->free = kfree;
3856 secattr->cache->data = sid_cache;
3857 secattr->flags |= NETLBL_SECATTR_CACHE;
3858 }
3859
3860 /**
3861 * security_netlbl_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
3862 * @state: SELinux state
3863 * @secattr: the NetLabel packet security attributes
3864 * @sid: the SELinux SID
3865 *
3866 * Description:
3867 * Convert the given NetLabel security attributes in @secattr into a
3868 * SELinux SID. If the @secattr field does not contain a full SELinux
3869 * SID/context then use SECINITSID_NETMSG as the foundation. If possible the
3870 * 'cache' field of @secattr is set and the CACHE flag is set; this is to
3871 * allow the @secattr to be used by NetLabel to cache the secattr to SID
3872 * conversion for future lookups. Returns zero on success, negative values on
3873 * failure.
3874 *
3875 */
security_netlbl_secattr_to_sid(struct selinux_state * state,struct netlbl_lsm_secattr * secattr,u32 * sid)3876 int security_netlbl_secattr_to_sid(struct selinux_state *state,
3877 struct netlbl_lsm_secattr *secattr,
3878 u32 *sid)
3879 {
3880 struct selinux_policy *policy;
3881 struct policydb *policydb;
3882 struct sidtab *sidtab;
3883 int rc;
3884 struct context *ctx;
3885 struct context ctx_new;
3886
3887 if (!selinux_initialized(state)) {
3888 *sid = SECSID_NULL;
3889 return 0;
3890 }
3891
3892 retry:
3893 rc = 0;
3894 rcu_read_lock();
3895 policy = rcu_dereference(state->policy);
3896 policydb = &policy->policydb;
3897 sidtab = policy->sidtab;
3898
3899 if (secattr->flags & NETLBL_SECATTR_CACHE)
3900 *sid = *(u32 *)secattr->cache->data;
3901 else if (secattr->flags & NETLBL_SECATTR_SECID)
3902 *sid = secattr->attr.secid;
3903 else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
3904 rc = -EIDRM;
3905 ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
3906 if (ctx == NULL)
3907 goto out;
3908
3909 context_init(&ctx_new);
3910 ctx_new.user = ctx->user;
3911 ctx_new.role = ctx->role;
3912 ctx_new.type = ctx->type;
3913 mls_import_netlbl_lvl(policydb, &ctx_new, secattr);
3914 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
3915 rc = mls_import_netlbl_cat(policydb, &ctx_new, secattr);
3916 if (rc)
3917 goto out;
3918 }
3919 rc = -EIDRM;
3920 if (!mls_context_isvalid(policydb, &ctx_new)) {
3921 ebitmap_destroy(&ctx_new.range.level[0].cat);
3922 goto out;
3923 }
3924
3925 rc = sidtab_context_to_sid(sidtab, &ctx_new, sid);
3926 ebitmap_destroy(&ctx_new.range.level[0].cat);
3927 if (rc == -ESTALE) {
3928 rcu_read_unlock();
3929 goto retry;
3930 }
3931 if (rc)
3932 goto out;
3933
3934 security_netlbl_cache_add(secattr, *sid);
3935 } else
3936 *sid = SECSID_NULL;
3937
3938 out:
3939 rcu_read_unlock();
3940 return rc;
3941 }
3942
3943 /**
3944 * security_netlbl_sid_to_secattr - Convert a SELinux SID to a NetLabel secattr
3945 * @state: SELinux state
3946 * @sid: the SELinux SID
3947 * @secattr: the NetLabel packet security attributes
3948 *
3949 * Description:
3950 * Convert the given SELinux SID in @sid into a NetLabel security attribute.
3951 * Returns zero on success, negative values on failure.
3952 *
3953 */
security_netlbl_sid_to_secattr(struct selinux_state * state,u32 sid,struct netlbl_lsm_secattr * secattr)3954 int security_netlbl_sid_to_secattr(struct selinux_state *state,
3955 u32 sid, struct netlbl_lsm_secattr *secattr)
3956 {
3957 struct selinux_policy *policy;
3958 struct policydb *policydb;
3959 int rc;
3960 struct context *ctx;
3961
3962 if (!selinux_initialized(state))
3963 return 0;
3964
3965 rcu_read_lock();
3966 policy = rcu_dereference(state->policy);
3967 policydb = &policy->policydb;
3968
3969 rc = -ENOENT;
3970 ctx = sidtab_search(policy->sidtab, sid);
3971 if (ctx == NULL)
3972 goto out;
3973
3974 rc = -ENOMEM;
3975 secattr->domain = kstrdup(sym_name(policydb, SYM_TYPES, ctx->type - 1),
3976 GFP_ATOMIC);
3977 if (secattr->domain == NULL)
3978 goto out;
3979
3980 secattr->attr.secid = sid;
3981 secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
3982 mls_export_netlbl_lvl(policydb, ctx, secattr);
3983 rc = mls_export_netlbl_cat(policydb, ctx, secattr);
3984 out:
3985 rcu_read_unlock();
3986 return rc;
3987 }
3988 #endif /* CONFIG_NETLABEL */
3989
3990 /**
3991 * __security_read_policy - read the policy.
3992 * @policy: SELinux policy
3993 * @data: binary policy data
3994 * @len: length of data in bytes
3995 *
3996 */
__security_read_policy(struct selinux_policy * policy,void * data,size_t * len)3997 static int __security_read_policy(struct selinux_policy *policy,
3998 void *data, size_t *len)
3999 {
4000 int rc;
4001 struct policy_file fp;
4002
4003 fp.data = data;
4004 fp.len = *len;
4005
4006 rc = policydb_write(&policy->policydb, &fp);
4007 if (rc)
4008 return rc;
4009
4010 *len = (unsigned long)fp.data - (unsigned long)data;
4011 return 0;
4012 }
4013
4014 /**
4015 * security_read_policy - read the policy.
4016 * @state: selinux_state
4017 * @data: binary policy data
4018 * @len: length of data in bytes
4019 *
4020 */
security_read_policy(struct selinux_state * state,void ** data,size_t * len)4021 int security_read_policy(struct selinux_state *state,
4022 void **data, size_t *len)
4023 {
4024 struct selinux_policy *policy;
4025
4026 policy = rcu_dereference_protected(
4027 state->policy, lockdep_is_held(&state->policy_mutex));
4028 if (!policy)
4029 return -EINVAL;
4030
4031 *len = policy->policydb.len;
4032 *data = vmalloc_user(*len);
4033 if (!*data)
4034 return -ENOMEM;
4035
4036 return __security_read_policy(policy, *data, len);
4037 }
4038
4039 /**
4040 * security_read_state_kernel - read the policy.
4041 * @state: selinux_state
4042 * @data: binary policy data
4043 * @len: length of data in bytes
4044 *
4045 * Allocates kernel memory for reading SELinux policy.
4046 * This function is for internal use only and should not
4047 * be used for returning data to user space.
4048 *
4049 * This function must be called with policy_mutex held.
4050 */
security_read_state_kernel(struct selinux_state * state,void ** data,size_t * len)4051 int security_read_state_kernel(struct selinux_state *state,
4052 void **data, size_t *len)
4053 {
4054 struct selinux_policy *policy;
4055
4056 policy = rcu_dereference_protected(
4057 state->policy, lockdep_is_held(&state->policy_mutex));
4058 if (!policy)
4059 return -EINVAL;
4060
4061 *len = policy->policydb.len;
4062 *data = vmalloc(*len);
4063 if (!*data)
4064 return -ENOMEM;
4065
4066 return __security_read_policy(policy, *data, len);
4067 }
4068