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