1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Implementation of the security services.
4  *
5  * Authors : Stephen Smalley, <sds@tycho.nsa.gov>
6  *	     James Morris <jmorris@redhat.com>
7  *
8  * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
9  *
10  *	Support for enhanced MLS infrastructure.
11  *	Support for context based audit filters.
12  *
13  * Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
14  *
15  *	Added conditional policy language extensions
16  *
17  * Updated: Hewlett-Packard <paul@paul-moore.com>
18  *
19  *      Added support for NetLabel
20  *      Added support for the policy capability bitmap
21  *
22  * Updated: Chad Sellers <csellers@tresys.com>
23  *
24  *  Added validation of kernel classes and permissions
25  *
26  * Updated: KaiGai Kohei <kaigai@ak.jp.nec.com>
27  *
28  *  Added support for bounds domain and audit messaged on masked permissions
29  *
30  * Updated: Guido Trentalancia <guido@trentalancia.com>
31  *
32  *  Added support for runtime switching of the policy type
33  *
34  * Copyright (C) 2008, 2009 NEC Corporation
35  * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
36  * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
37  * Copyright (C) 2003 - 2004, 2006 Tresys Technology, LLC
38  * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
39  */
40 #include <linux/kernel.h>
41 #include <linux/slab.h>
42 #include <linux/string.h>
43 #include <linux/spinlock.h>
44 #include <linux/rcupdate.h>
45 #include <linux/errno.h>
46 #include <linux/in.h>
47 #include <linux/sched.h>
48 #include <linux/audit.h>
49 #include <linux/vmalloc.h>
50 #include <linux/lsm_hooks.h>
51 #include <net/netlabel.h>
52 
53 #include "flask.h"
54 #include "avc.h"
55 #include "avc_ss.h"
56 #include "security.h"
57 #include "context.h"
58 #include "policydb.h"
59 #include "sidtab.h"
60 #include "services.h"
61 #include "conditional.h"
62 #include "mls.h"
63 #include "objsec.h"
64 #include "netlabel.h"
65 #include "xfrm.h"
66 #include "ebitmap.h"
67 #include "audit.h"
68 #include "policycap_names.h"
69 #include "ima.h"
70 
71 struct convert_context_args {
72 	struct selinux_state *state;
73 	struct policydb *oldp;
74 	struct policydb *newp;
75 };
76 
77 struct selinux_policy_convert_data {
78 	struct convert_context_args args;
79 	struct sidtab_convert_params sidtab_params;
80 };
81 
82 /* Forward declaration. */
83 static int context_struct_to_string(struct policydb *policydb,
84 				    struct context *context,
85 				    char **scontext,
86 				    u32 *scontext_len);
87 
88 static int sidtab_entry_to_string(struct policydb *policydb,
89 				  struct sidtab *sidtab,
90 				  struct sidtab_entry *entry,
91 				  char **scontext,
92 				  u32 *scontext_len);
93 
94 static void context_struct_compute_av(struct policydb *policydb,
95 				      struct context *scontext,
96 				      struct context *tcontext,
97 				      u16 tclass,
98 				      struct av_decision *avd,
99 				      struct extended_perms *xperms);
100 
selinux_set_mapping(struct policydb * pol,const struct security_class_mapping * map,struct selinux_map * out_map)101 static int selinux_set_mapping(struct policydb *pol,
102 			       const struct security_class_mapping *map,
103 			       struct selinux_map *out_map)
104 {
105 	u16 i, j;
106 	unsigned k;
107 	bool print_unknown_handle = false;
108 
109 	/* Find number of classes in the input mapping */
110 	if (!map)
111 		return -EINVAL;
112 	i = 0;
113 	while (map[i].name)
114 		i++;
115 
116 	/* Allocate space for the class records, plus one for class zero */
117 	out_map->mapping = kcalloc(++i, sizeof(*out_map->mapping), GFP_ATOMIC);
118 	if (!out_map->mapping)
119 		return -ENOMEM;
120 
121 	/* Store the raw class and permission values */
122 	j = 0;
123 	while (map[j].name) {
124 		const struct security_class_mapping *p_in = map + (j++);
125 		struct selinux_mapping *p_out = out_map->mapping + j;
126 
127 		/* An empty class string skips ahead */
128 		if (!strcmp(p_in->name, "")) {
129 			p_out->num_perms = 0;
130 			continue;
131 		}
132 
133 		p_out->value = string_to_security_class(pol, p_in->name);
134 		if (!p_out->value) {
135 			pr_info("SELinux:  Class %s not defined in policy.\n",
136 			       p_in->name);
137 			if (pol->reject_unknown)
138 				goto err;
139 			p_out->num_perms = 0;
140 			print_unknown_handle = true;
141 			continue;
142 		}
143 
144 		k = 0;
145 		while (p_in->perms[k]) {
146 			/* An empty permission string skips ahead */
147 			if (!*p_in->perms[k]) {
148 				k++;
149 				continue;
150 			}
151 			p_out->perms[k] = string_to_av_perm(pol, p_out->value,
152 							    p_in->perms[k]);
153 			if (!p_out->perms[k]) {
154 				pr_info("SELinux:  Permission %s in class %s not defined in policy.\n",
155 				       p_in->perms[k], p_in->name);
156 				if (pol->reject_unknown)
157 					goto err;
158 				print_unknown_handle = true;
159 			}
160 
161 			k++;
162 		}
163 		p_out->num_perms = k;
164 	}
165 
166 	if (print_unknown_handle)
167 		pr_info("SELinux: the above unknown classes and permissions will be %s\n",
168 		       pol->allow_unknown ? "allowed" : "denied");
169 
170 	out_map->size = i;
171 	return 0;
172 err:
173 	kfree(out_map->mapping);
174 	out_map->mapping = NULL;
175 	return -EINVAL;
176 }
177 
178 /*
179  * Get real, policy values from mapped values
180  */
181 
unmap_class(struct selinux_map * map,u16 tclass)182 static u16 unmap_class(struct selinux_map *map, u16 tclass)
183 {
184 	if (tclass < map->size)
185 		return map->mapping[tclass].value;
186 
187 	return tclass;
188 }
189 
190 /*
191  * Get kernel value for class from its policy value
192  */
map_class(struct selinux_map * map,u16 pol_value)193 static u16 map_class(struct selinux_map *map, u16 pol_value)
194 {
195 	u16 i;
196 
197 	for (i = 1; i < map->size; i++) {
198 		if (map->mapping[i].value == pol_value)
199 			return i;
200 	}
201 
202 	return SECCLASS_NULL;
203 }
204 
map_decision(struct selinux_map * map,u16 tclass,struct av_decision * avd,int allow_unknown)205 static void map_decision(struct selinux_map *map,
206 			 u16 tclass, struct av_decision *avd,
207 			 int allow_unknown)
208 {
209 	if (tclass < map->size) {
210 		struct selinux_mapping *mapping = &map->mapping[tclass];
211 		unsigned int i, n = mapping->num_perms;
212 		u32 result;
213 
214 		for (i = 0, result = 0; i < n; i++) {
215 			if (avd->allowed & mapping->perms[i])
216 				result |= 1<<i;
217 			if (allow_unknown && !mapping->perms[i])
218 				result |= 1<<i;
219 		}
220 		avd->allowed = result;
221 
222 		for (i = 0, result = 0; i < n; i++)
223 			if (avd->auditallow & mapping->perms[i])
224 				result |= 1<<i;
225 		avd->auditallow = result;
226 
227 		for (i = 0, result = 0; i < n; i++) {
228 			if (avd->auditdeny & mapping->perms[i])
229 				result |= 1<<i;
230 			if (!allow_unknown && !mapping->perms[i])
231 				result |= 1<<i;
232 		}
233 		/*
234 		 * In case the kernel has a bug and requests a permission
235 		 * between num_perms and the maximum permission number, we
236 		 * should audit that denial
237 		 */
238 		for (; i < (sizeof(u32)*8); i++)
239 			result |= 1<<i;
240 		avd->auditdeny = result;
241 	}
242 }
243 
security_mls_enabled(struct selinux_state * state)244 int security_mls_enabled(struct selinux_state *state)
245 {
246 	int mls_enabled;
247 	struct selinux_policy *policy;
248 
249 	if (!selinux_initialized(state))
250 		return 0;
251 
252 	rcu_read_lock();
253 	policy = rcu_dereference(state->policy);
254 	mls_enabled = policy->policydb.mls_enabled;
255 	rcu_read_unlock();
256 	return mls_enabled;
257 }
258 
259 /*
260  * Return the boolean value of a constraint expression
261  * when it is applied to the specified source and target
262  * security contexts.
263  *
264  * xcontext is a special beast...  It is used by the validatetrans rules
265  * only.  For these rules, scontext is the context before the transition,
266  * tcontext is the context after the transition, and xcontext is the context
267  * of the process performing the transition.  All other callers of
268  * constraint_expr_eval should pass in NULL for xcontext.
269  */
constraint_expr_eval(struct policydb * policydb,struct context * scontext,struct context * tcontext,struct context * xcontext,struct constraint_expr * cexpr)270 static int constraint_expr_eval(struct policydb *policydb,
271 				struct context *scontext,
272 				struct context *tcontext,
273 				struct context *xcontext,
274 				struct constraint_expr *cexpr)
275 {
276 	u32 val1, val2;
277 	struct context *c;
278 	struct role_datum *r1, *r2;
279 	struct mls_level *l1, *l2;
280 	struct constraint_expr *e;
281 	int s[CEXPR_MAXDEPTH];
282 	int sp = -1;
283 
284 	for (e = cexpr; e; e = e->next) {
285 		switch (e->expr_type) {
286 		case CEXPR_NOT:
287 			BUG_ON(sp < 0);
288 			s[sp] = !s[sp];
289 			break;
290 		case CEXPR_AND:
291 			BUG_ON(sp < 1);
292 			sp--;
293 			s[sp] &= s[sp + 1];
294 			break;
295 		case CEXPR_OR:
296 			BUG_ON(sp < 1);
297 			sp--;
298 			s[sp] |= s[sp + 1];
299 			break;
300 		case CEXPR_ATTR:
301 			if (sp == (CEXPR_MAXDEPTH - 1))
302 				return 0;
303 			switch (e->attr) {
304 			case CEXPR_USER:
305 				val1 = scontext->user;
306 				val2 = tcontext->user;
307 				break;
308 			case CEXPR_TYPE:
309 				val1 = scontext->type;
310 				val2 = tcontext->type;
311 				break;
312 			case CEXPR_ROLE:
313 				val1 = scontext->role;
314 				val2 = tcontext->role;
315 				r1 = policydb->role_val_to_struct[val1 - 1];
316 				r2 = policydb->role_val_to_struct[val2 - 1];
317 				switch (e->op) {
318 				case CEXPR_DOM:
319 					s[++sp] = ebitmap_get_bit(&r1->dominates,
320 								  val2 - 1);
321 					continue;
322 				case CEXPR_DOMBY:
323 					s[++sp] = ebitmap_get_bit(&r2->dominates,
324 								  val1 - 1);
325 					continue;
326 				case CEXPR_INCOMP:
327 					s[++sp] = (!ebitmap_get_bit(&r1->dominates,
328 								    val2 - 1) &&
329 						   !ebitmap_get_bit(&r2->dominates,
330 								    val1 - 1));
331 					continue;
332 				default:
333 					break;
334 				}
335 				break;
336 			case CEXPR_L1L2:
337 				l1 = &(scontext->range.level[0]);
338 				l2 = &(tcontext->range.level[0]);
339 				goto mls_ops;
340 			case CEXPR_L1H2:
341 				l1 = &(scontext->range.level[0]);
342 				l2 = &(tcontext->range.level[1]);
343 				goto mls_ops;
344 			case CEXPR_H1L2:
345 				l1 = &(scontext->range.level[1]);
346 				l2 = &(tcontext->range.level[0]);
347 				goto mls_ops;
348 			case CEXPR_H1H2:
349 				l1 = &(scontext->range.level[1]);
350 				l2 = &(tcontext->range.level[1]);
351 				goto mls_ops;
352 			case CEXPR_L1H1:
353 				l1 = &(scontext->range.level[0]);
354 				l2 = &(scontext->range.level[1]);
355 				goto mls_ops;
356 			case CEXPR_L2H2:
357 				l1 = &(tcontext->range.level[0]);
358 				l2 = &(tcontext->range.level[1]);
359 				goto mls_ops;
360 mls_ops:
361 				switch (e->op) {
362 				case CEXPR_EQ:
363 					s[++sp] = mls_level_eq(l1, l2);
364 					continue;
365 				case CEXPR_NEQ:
366 					s[++sp] = !mls_level_eq(l1, l2);
367 					continue;
368 				case CEXPR_DOM:
369 					s[++sp] = mls_level_dom(l1, l2);
370 					continue;
371 				case CEXPR_DOMBY:
372 					s[++sp] = mls_level_dom(l2, l1);
373 					continue;
374 				case CEXPR_INCOMP:
375 					s[++sp] = mls_level_incomp(l2, l1);
376 					continue;
377 				default:
378 					BUG();
379 					return 0;
380 				}
381 				break;
382 			default:
383 				BUG();
384 				return 0;
385 			}
386 
387 			switch (e->op) {
388 			case CEXPR_EQ:
389 				s[++sp] = (val1 == val2);
390 				break;
391 			case CEXPR_NEQ:
392 				s[++sp] = (val1 != val2);
393 				break;
394 			default:
395 				BUG();
396 				return 0;
397 			}
398 			break;
399 		case CEXPR_NAMES:
400 			if (sp == (CEXPR_MAXDEPTH-1))
401 				return 0;
402 			c = scontext;
403 			if (e->attr & CEXPR_TARGET)
404 				c = tcontext;
405 			else if (e->attr & CEXPR_XTARGET) {
406 				c = xcontext;
407 				if (!c) {
408 					BUG();
409 					return 0;
410 				}
411 			}
412 			if (e->attr & CEXPR_USER)
413 				val1 = c->user;
414 			else if (e->attr & CEXPR_ROLE)
415 				val1 = c->role;
416 			else if (e->attr & CEXPR_TYPE)
417 				val1 = c->type;
418 			else {
419 				BUG();
420 				return 0;
421 			}
422 
423 			switch (e->op) {
424 			case CEXPR_EQ:
425 				s[++sp] = ebitmap_get_bit(&e->names, val1 - 1);
426 				break;
427 			case CEXPR_NEQ:
428 				s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1);
429 				break;
430 			default:
431 				BUG();
432 				return 0;
433 			}
434 			break;
435 		default:
436 			BUG();
437 			return 0;
438 		}
439 	}
440 
441 	BUG_ON(sp != 0);
442 	return s[0];
443 }
444 
445 /*
446  * security_dump_masked_av - dumps masked permissions during
447  * security_compute_av due to RBAC, MLS/Constraint and Type bounds.
448  */
dump_masked_av_helper(void * k,void * d,void * args)449 static int dump_masked_av_helper(void *k, void *d, void *args)
450 {
451 	struct perm_datum *pdatum = d;
452 	char **permission_names = args;
453 
454 	BUG_ON(pdatum->value < 1 || pdatum->value > 32);
455 
456 	permission_names[pdatum->value - 1] = (char *)k;
457 
458 	return 0;
459 }
460 
security_dump_masked_av(struct policydb * policydb,struct context * scontext,struct context * tcontext,u16 tclass,u32 permissions,const char * reason)461 static void security_dump_masked_av(struct policydb *policydb,
462 				    struct context *scontext,
463 				    struct context *tcontext,
464 				    u16 tclass,
465 				    u32 permissions,
466 				    const char *reason)
467 {
468 	struct common_datum *common_dat;
469 	struct class_datum *tclass_dat;
470 	struct audit_buffer *ab;
471 	char *tclass_name;
472 	char *scontext_name = NULL;
473 	char *tcontext_name = NULL;
474 	char *permission_names[32];
475 	int index;
476 	u32 length;
477 	bool need_comma = false;
478 
479 	if (!permissions)
480 		return;
481 
482 	tclass_name = sym_name(policydb, SYM_CLASSES, tclass - 1);
483 	tclass_dat = policydb->class_val_to_struct[tclass - 1];
484 	common_dat = tclass_dat->comdatum;
485 
486 	/* init permission_names */
487 	if (common_dat &&
488 	    hashtab_map(&common_dat->permissions.table,
489 			dump_masked_av_helper, permission_names) < 0)
490 		goto out;
491 
492 	if (hashtab_map(&tclass_dat->permissions.table,
493 			dump_masked_av_helper, permission_names) < 0)
494 		goto out;
495 
496 	/* get scontext/tcontext in text form */
497 	if (context_struct_to_string(policydb, scontext,
498 				     &scontext_name, &length) < 0)
499 		goto out;
500 
501 	if (context_struct_to_string(policydb, tcontext,
502 				     &tcontext_name, &length) < 0)
503 		goto out;
504 
505 	/* audit a message */
506 	ab = audit_log_start(audit_context(),
507 			     GFP_ATOMIC, AUDIT_SELINUX_ERR);
508 	if (!ab)
509 		goto out;
510 
511 	audit_log_format(ab, "op=security_compute_av reason=%s "
512 			 "scontext=%s tcontext=%s tclass=%s perms=",
513 			 reason, scontext_name, tcontext_name, tclass_name);
514 
515 	for (index = 0; index < 32; index++) {
516 		u32 mask = (1 << index);
517 
518 		if ((mask & permissions) == 0)
519 			continue;
520 
521 		audit_log_format(ab, "%s%s",
522 				 need_comma ? "," : "",
523 				 permission_names[index]
524 				 ? permission_names[index] : "????");
525 		need_comma = true;
526 	}
527 	audit_log_end(ab);
528 out:
529 	/* release scontext/tcontext */
530 	kfree(tcontext_name);
531 	kfree(scontext_name);
532 }
533 
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 	xperms->len = 1;
611 }
612 
613 /*
614  * Compute access vectors and extended permissions based on a context
615  * structure pair for the permissions in a particular class.
616  */
context_struct_compute_av(struct policydb * policydb,struct context * scontext,struct context * tcontext,u16 tclass,struct av_decision * avd,struct extended_perms * xperms)617 static void context_struct_compute_av(struct policydb *policydb,
618 				      struct context *scontext,
619 				      struct context *tcontext,
620 				      u16 tclass,
621 				      struct av_decision *avd,
622 				      struct extended_perms *xperms)
623 {
624 	struct constraint_node *constraint;
625 	struct role_allow *ra;
626 	struct avtab_key avkey;
627 	struct avtab_node *node;
628 	struct class_datum *tclass_datum;
629 	struct ebitmap *sattr, *tattr;
630 	struct ebitmap_node *snode, *tnode;
631 	unsigned int i, j;
632 
633 	avd->allowed = 0;
634 	avd->auditallow = 0;
635 	avd->auditdeny = 0xffffffff;
636 	if (xperms) {
637 		memset(&xperms->drivers, 0, sizeof(xperms->drivers));
638 		xperms->len = 0;
639 	}
640 
641 	if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
642 		if (printk_ratelimit())
643 			pr_warn("SELinux:  Invalid class %hu\n", tclass);
644 		return;
645 	}
646 
647 	tclass_datum = policydb->class_val_to_struct[tclass - 1];
648 
649 	/*
650 	 * If a specific type enforcement rule was defined for
651 	 * this permission check, then use it.
652 	 */
653 	avkey.target_class = tclass;
654 	avkey.specified = AVTAB_AV | AVTAB_XPERMS;
655 	sattr = &policydb->type_attr_map_array[scontext->type - 1];
656 	tattr = &policydb->type_attr_map_array[tcontext->type - 1];
657 	ebitmap_for_each_positive_bit(sattr, snode, i) {
658 		ebitmap_for_each_positive_bit(tattr, tnode, j) {
659 			avkey.source_type = i + 1;
660 			avkey.target_type = j + 1;
661 			for (node = avtab_search_node(&policydb->te_avtab,
662 						      &avkey);
663 			     node;
664 			     node = avtab_search_node_next(node, avkey.specified)) {
665 				if (node->key.specified == AVTAB_ALLOWED)
666 					avd->allowed |= node->datum.u.data;
667 				else if (node->key.specified == AVTAB_AUDITALLOW)
668 					avd->auditallow |= node->datum.u.data;
669 				else if (node->key.specified == AVTAB_AUDITDENY)
670 					avd->auditdeny &= node->datum.u.data;
671 				else if (xperms && (node->key.specified & AVTAB_XPERMS))
672 					services_compute_xperms_drivers(xperms, node);
673 			}
674 
675 			/* Check conditional av table for additional permissions */
676 			cond_compute_av(&policydb->te_cond_avtab, &avkey,
677 					avd, xperms);
678 
679 		}
680 	}
681 
682 	/*
683 	 * Remove any permissions prohibited by a constraint (this includes
684 	 * the MLS policy).
685 	 */
686 	constraint = tclass_datum->constraints;
687 	while (constraint) {
688 		if ((constraint->permissions & (avd->allowed)) &&
689 		    !constraint_expr_eval(policydb, scontext, tcontext, NULL,
690 					  constraint->expr)) {
691 			avd->allowed &= ~(constraint->permissions);
692 		}
693 		constraint = constraint->next;
694 	}
695 
696 	/*
697 	 * If checking process transition permission and the
698 	 * role is changing, then check the (current_role, new_role)
699 	 * pair.
700 	 */
701 	if (tclass == policydb->process_class &&
702 	    (avd->allowed & policydb->process_trans_perms) &&
703 	    scontext->role != tcontext->role) {
704 		for (ra = policydb->role_allow; ra; ra = ra->next) {
705 			if (scontext->role == ra->role &&
706 			    tcontext->role == ra->new_role)
707 				break;
708 		}
709 		if (!ra)
710 			avd->allowed &= ~policydb->process_trans_perms;
711 	}
712 
713 	/*
714 	 * If the given source and target types have boundary
715 	 * constraint, lazy checks have to mask any violated
716 	 * permission and notice it to userspace via audit.
717 	 */
718 	type_attribute_bounds_av(policydb, scontext, tcontext,
719 				 tclass, avd);
720 }
721 
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)722 static int security_validtrans_handle_fail(struct selinux_state *state,
723 					struct selinux_policy *policy,
724 					struct sidtab_entry *oentry,
725 					struct sidtab_entry *nentry,
726 					struct sidtab_entry *tentry,
727 					u16 tclass)
728 {
729 	struct policydb *p = &policy->policydb;
730 	struct sidtab *sidtab = policy->sidtab;
731 	char *o = NULL, *n = NULL, *t = NULL;
732 	u32 olen, nlen, tlen;
733 
734 	if (sidtab_entry_to_string(p, sidtab, oentry, &o, &olen))
735 		goto out;
736 	if (sidtab_entry_to_string(p, sidtab, nentry, &n, &nlen))
737 		goto out;
738 	if (sidtab_entry_to_string(p, sidtab, tentry, &t, &tlen))
739 		goto out;
740 	audit_log(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR,
741 		  "op=security_validate_transition seresult=denied"
742 		  " oldcontext=%s newcontext=%s taskcontext=%s tclass=%s",
743 		  o, n, t, sym_name(p, SYM_CLASSES, tclass-1));
744 out:
745 	kfree(o);
746 	kfree(n);
747 	kfree(t);
748 
749 	if (!enforcing_enabled(state))
750 		return 0;
751 	return -EPERM;
752 }
753 
security_compute_validatetrans(struct selinux_state * state,u32 oldsid,u32 newsid,u32 tasksid,u16 orig_tclass,bool user)754 static int security_compute_validatetrans(struct selinux_state *state,
755 					  u32 oldsid, u32 newsid, u32 tasksid,
756 					  u16 orig_tclass, bool user)
757 {
758 	struct selinux_policy *policy;
759 	struct policydb *policydb;
760 	struct sidtab *sidtab;
761 	struct sidtab_entry *oentry;
762 	struct sidtab_entry *nentry;
763 	struct sidtab_entry *tentry;
764 	struct class_datum *tclass_datum;
765 	struct constraint_node *constraint;
766 	u16 tclass;
767 	int rc = 0;
768 
769 
770 	if (!selinux_initialized(state))
771 		return 0;
772 
773 	rcu_read_lock();
774 
775 	policy = rcu_dereference(state->policy);
776 	policydb = &policy->policydb;
777 	sidtab = policy->sidtab;
778 
779 	if (!user)
780 		tclass = unmap_class(&policy->map, orig_tclass);
781 	else
782 		tclass = orig_tclass;
783 
784 	if (!tclass || tclass > policydb->p_classes.nprim) {
785 		rc = -EINVAL;
786 		goto out;
787 	}
788 	tclass_datum = policydb->class_val_to_struct[tclass - 1];
789 
790 	oentry = sidtab_search_entry(sidtab, oldsid);
791 	if (!oentry) {
792 		pr_err("SELinux: %s:  unrecognized SID %d\n",
793 			__func__, oldsid);
794 		rc = -EINVAL;
795 		goto out;
796 	}
797 
798 	nentry = sidtab_search_entry(sidtab, newsid);
799 	if (!nentry) {
800 		pr_err("SELinux: %s:  unrecognized SID %d\n",
801 			__func__, newsid);
802 		rc = -EINVAL;
803 		goto out;
804 	}
805 
806 	tentry = sidtab_search_entry(sidtab, tasksid);
807 	if (!tentry) {
808 		pr_err("SELinux: %s:  unrecognized SID %d\n",
809 			__func__, tasksid);
810 		rc = -EINVAL;
811 		goto out;
812 	}
813 
814 	constraint = tclass_datum->validatetrans;
815 	while (constraint) {
816 		if (!constraint_expr_eval(policydb, &oentry->context,
817 					  &nentry->context, &tentry->context,
818 					  constraint->expr)) {
819 			if (user)
820 				rc = -EPERM;
821 			else
822 				rc = security_validtrans_handle_fail(state,
823 								policy,
824 								oentry,
825 								nentry,
826 								tentry,
827 								tclass);
828 			goto out;
829 		}
830 		constraint = constraint->next;
831 	}
832 
833 out:
834 	rcu_read_unlock();
835 	return rc;
836 }
837 
security_validate_transition_user(struct selinux_state * state,u32 oldsid,u32 newsid,u32 tasksid,u16 tclass)838 int security_validate_transition_user(struct selinux_state *state,
839 				      u32 oldsid, u32 newsid, u32 tasksid,
840 				      u16 tclass)
841 {
842 	return security_compute_validatetrans(state, oldsid, newsid, tasksid,
843 					      tclass, true);
844 }
845 
security_validate_transition(struct selinux_state * state,u32 oldsid,u32 newsid,u32 tasksid,u16 orig_tclass)846 int security_validate_transition(struct selinux_state *state,
847 				 u32 oldsid, u32 newsid, u32 tasksid,
848 				 u16 orig_tclass)
849 {
850 	return security_compute_validatetrans(state, oldsid, newsid, tasksid,
851 					      orig_tclass, false);
852 }
853 
854 /*
855  * security_bounded_transition - check whether the given
856  * transition is directed to bounded, or not.
857  * It returns 0, if @newsid is bounded by @oldsid.
858  * Otherwise, it returns error code.
859  *
860  * @state: SELinux state
861  * @oldsid : current security identifier
862  * @newsid : destinated security identifier
863  */
security_bounded_transition(struct selinux_state * state,u32 old_sid,u32 new_sid)864 int security_bounded_transition(struct selinux_state *state,
865 				u32 old_sid, u32 new_sid)
866 {
867 	struct selinux_policy *policy;
868 	struct policydb *policydb;
869 	struct sidtab *sidtab;
870 	struct sidtab_entry *old_entry, *new_entry;
871 	struct type_datum *type;
872 	int index;
873 	int rc;
874 
875 	if (!selinux_initialized(state))
876 		return 0;
877 
878 	rcu_read_lock();
879 	policy = rcu_dereference(state->policy);
880 	policydb = &policy->policydb;
881 	sidtab = policy->sidtab;
882 
883 	rc = -EINVAL;
884 	old_entry = sidtab_search_entry(sidtab, old_sid);
885 	if (!old_entry) {
886 		pr_err("SELinux: %s: unrecognized SID %u\n",
887 		       __func__, old_sid);
888 		goto out;
889 	}
890 
891 	rc = -EINVAL;
892 	new_entry = sidtab_search_entry(sidtab, new_sid);
893 	if (!new_entry) {
894 		pr_err("SELinux: %s: unrecognized SID %u\n",
895 		       __func__, new_sid);
896 		goto out;
897 	}
898 
899 	rc = 0;
900 	/* type/domain unchanged */
901 	if (old_entry->context.type == new_entry->context.type)
902 		goto out;
903 
904 	index = new_entry->context.type;
905 	while (true) {
906 		type = policydb->type_val_to_struct[index - 1];
907 		BUG_ON(!type);
908 
909 		/* not bounded anymore */
910 		rc = -EPERM;
911 		if (!type->bounds)
912 			break;
913 
914 		/* @newsid is bounded by @oldsid */
915 		rc = 0;
916 		if (type->bounds == old_entry->context.type)
917 			break;
918 
919 		index = type->bounds;
920 	}
921 
922 	if (rc) {
923 		char *old_name = NULL;
924 		char *new_name = NULL;
925 		u32 length;
926 
927 		if (!sidtab_entry_to_string(policydb, sidtab, old_entry,
928 					    &old_name, &length) &&
929 		    !sidtab_entry_to_string(policydb, sidtab, new_entry,
930 					    &new_name, &length)) {
931 			audit_log(audit_context(),
932 				  GFP_ATOMIC, AUDIT_SELINUX_ERR,
933 				  "op=security_bounded_transition "
934 				  "seresult=denied "
935 				  "oldcontext=%s newcontext=%s",
936 				  old_name, new_name);
937 		}
938 		kfree(new_name);
939 		kfree(old_name);
940 	}
941 out:
942 	rcu_read_unlock();
943 
944 	return rc;
945 }
946 
avd_init(struct selinux_policy * policy,struct av_decision * avd)947 static void avd_init(struct selinux_policy *policy, struct av_decision *avd)
948 {
949 	avd->allowed = 0;
950 	avd->auditallow = 0;
951 	avd->auditdeny = 0xffffffff;
952 	if (policy)
953 		avd->seqno = policy->latest_granting;
954 	else
955 		avd->seqno = 0;
956 	avd->flags = 0;
957 }
958 
services_compute_xperms_decision(struct extended_perms_decision * xpermd,struct avtab_node * node)959 void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
960 					struct avtab_node *node)
961 {
962 	unsigned int i;
963 
964 	if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
965 		if (xpermd->driver != node->datum.u.xperms->driver)
966 			return;
967 	} else if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
968 		if (!security_xperm_test(node->datum.u.xperms->perms.p,
969 					xpermd->driver))
970 			return;
971 	} else {
972 		BUG();
973 	}
974 
975 	if (node->key.specified == AVTAB_XPERMS_ALLOWED) {
976 		xpermd->used |= XPERMS_ALLOWED;
977 		if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
978 			memset(xpermd->allowed->p, 0xff,
979 					sizeof(xpermd->allowed->p));
980 		}
981 		if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
982 			for (i = 0; i < ARRAY_SIZE(xpermd->allowed->p); i++)
983 				xpermd->allowed->p[i] |=
984 					node->datum.u.xperms->perms.p[i];
985 		}
986 	} else if (node->key.specified == AVTAB_XPERMS_AUDITALLOW) {
987 		xpermd->used |= XPERMS_AUDITALLOW;
988 		if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
989 			memset(xpermd->auditallow->p, 0xff,
990 					sizeof(xpermd->auditallow->p));
991 		}
992 		if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
993 			for (i = 0; i < ARRAY_SIZE(xpermd->auditallow->p); i++)
994 				xpermd->auditallow->p[i] |=
995 					node->datum.u.xperms->perms.p[i];
996 		}
997 	} else if (node->key.specified == AVTAB_XPERMS_DONTAUDIT) {
998 		xpermd->used |= XPERMS_DONTAUDIT;
999 		if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLDRIVER) {
1000 			memset(xpermd->dontaudit->p, 0xff,
1001 					sizeof(xpermd->dontaudit->p));
1002 		}
1003 		if (node->datum.u.xperms->specified == AVTAB_XPERMS_IOCTLFUNCTION) {
1004 			for (i = 0; i < ARRAY_SIZE(xpermd->dontaudit->p); i++)
1005 				xpermd->dontaudit->p[i] |=
1006 					node->datum.u.xperms->perms.p[i];
1007 		}
1008 	} else {
1009 		BUG();
1010 	}
1011 }
1012 
security_compute_xperms_decision(struct selinux_state * state,u32 ssid,u32 tsid,u16 orig_tclass,u8 driver,struct extended_perms_decision * xpermd)1013 void security_compute_xperms_decision(struct selinux_state *state,
1014 				      u32 ssid,
1015 				      u32 tsid,
1016 				      u16 orig_tclass,
1017 				      u8 driver,
1018 				      struct extended_perms_decision *xpermd)
1019 {
1020 	struct selinux_policy *policy;
1021 	struct policydb *policydb;
1022 	struct sidtab *sidtab;
1023 	u16 tclass;
1024 	struct context *scontext, *tcontext;
1025 	struct avtab_key avkey;
1026 	struct avtab_node *node;
1027 	struct ebitmap *sattr, *tattr;
1028 	struct ebitmap_node *snode, *tnode;
1029 	unsigned int i, j;
1030 
1031 	xpermd->driver = driver;
1032 	xpermd->used = 0;
1033 	memset(xpermd->allowed->p, 0, sizeof(xpermd->allowed->p));
1034 	memset(xpermd->auditallow->p, 0, sizeof(xpermd->auditallow->p));
1035 	memset(xpermd->dontaudit->p, 0, sizeof(xpermd->dontaudit->p));
1036 
1037 	rcu_read_lock();
1038 	if (!selinux_initialized(state))
1039 		goto allow;
1040 
1041 	policy = rcu_dereference(state->policy);
1042 	policydb = &policy->policydb;
1043 	sidtab = policy->sidtab;
1044 
1045 	scontext = sidtab_search(sidtab, ssid);
1046 	if (!scontext) {
1047 		pr_err("SELinux: %s:  unrecognized SID %d\n",
1048 		       __func__, ssid);
1049 		goto out;
1050 	}
1051 
1052 	tcontext = sidtab_search(sidtab, tsid);
1053 	if (!tcontext) {
1054 		pr_err("SELinux: %s:  unrecognized SID %d\n",
1055 		       __func__, tsid);
1056 		goto out;
1057 	}
1058 
1059 	tclass = unmap_class(&policy->map, orig_tclass);
1060 	if (unlikely(orig_tclass && !tclass)) {
1061 		if (policydb->allow_unknown)
1062 			goto allow;
1063 		goto out;
1064 	}
1065 
1066 
1067 	if (unlikely(!tclass || tclass > policydb->p_classes.nprim)) {
1068 		pr_warn_ratelimited("SELinux:  Invalid class %hu\n", tclass);
1069 		goto out;
1070 	}
1071 
1072 	avkey.target_class = tclass;
1073 	avkey.specified = AVTAB_XPERMS;
1074 	sattr = &policydb->type_attr_map_array[scontext->type - 1];
1075 	tattr = &policydb->type_attr_map_array[tcontext->type - 1];
1076 	ebitmap_for_each_positive_bit(sattr, snode, i) {
1077 		ebitmap_for_each_positive_bit(tattr, tnode, j) {
1078 			avkey.source_type = i + 1;
1079 			avkey.target_type = j + 1;
1080 			for (node = avtab_search_node(&policydb->te_avtab,
1081 						      &avkey);
1082 			     node;
1083 			     node = avtab_search_node_next(node, avkey.specified))
1084 				services_compute_xperms_decision(xpermd, node);
1085 
1086 			cond_compute_xperms(&policydb->te_cond_avtab,
1087 						&avkey, xpermd);
1088 		}
1089 	}
1090 out:
1091 	rcu_read_unlock();
1092 	return;
1093 allow:
1094 	memset(xpermd->allowed->p, 0xff, sizeof(xpermd->allowed->p));
1095 	goto out;
1096 }
1097 
1098 /**
1099  * security_compute_av - Compute access vector decisions.
1100  * @state: SELinux state
1101  * @ssid: source security identifier
1102  * @tsid: target security identifier
1103  * @orig_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  * @state: SELinux state
1390  * @sid: security identifier, SID
1391  * @scontext: security context
1392  * @scontext_len: length in bytes
1393  *
1394  * Write the string representation of the context associated with @sid
1395  * into a dynamically allocated string of the correct size.  Set @scontext
1396  * to point to this string and set @scontext_len to the length of the string.
1397  */
security_sid_to_context(struct selinux_state * state,u32 sid,char ** scontext,u32 * scontext_len)1398 int security_sid_to_context(struct selinux_state *state,
1399 			    u32 sid, char **scontext, u32 *scontext_len)
1400 {
1401 	return security_sid_to_context_core(state, sid, scontext,
1402 					    scontext_len, 0, 0);
1403 }
1404 
security_sid_to_context_force(struct selinux_state * state,u32 sid,char ** scontext,u32 * scontext_len)1405 int security_sid_to_context_force(struct selinux_state *state, u32 sid,
1406 				  char **scontext, u32 *scontext_len)
1407 {
1408 	return security_sid_to_context_core(state, sid, scontext,
1409 					    scontext_len, 1, 0);
1410 }
1411 
1412 /**
1413  * security_sid_to_context_inval - Obtain a context for a given SID if it
1414  *                                 is invalid.
1415  * @state: SELinux state
1416  * @sid: security identifier, SID
1417  * @scontext: security context
1418  * @scontext_len: length in bytes
1419  *
1420  * Write the string representation of the context associated with @sid
1421  * into a dynamically allocated string of the correct size, but only if the
1422  * context is invalid in the current policy.  Set @scontext to point to
1423  * this string (or NULL if the context is valid) and set @scontext_len to
1424  * the length of the string (or 0 if the context is valid).
1425  */
security_sid_to_context_inval(struct selinux_state * state,u32 sid,char ** scontext,u32 * scontext_len)1426 int security_sid_to_context_inval(struct selinux_state *state, u32 sid,
1427 				  char **scontext, u32 *scontext_len)
1428 {
1429 	return security_sid_to_context_core(state, sid, scontext,
1430 					    scontext_len, 1, 1);
1431 }
1432 
1433 /*
1434  * Caveat:  Mutates scontext.
1435  */
string_to_context_struct(struct policydb * pol,struct sidtab * sidtabp,char * scontext,struct context * ctx,u32 def_sid)1436 static int string_to_context_struct(struct policydb *pol,
1437 				    struct sidtab *sidtabp,
1438 				    char *scontext,
1439 				    struct context *ctx,
1440 				    u32 def_sid)
1441 {
1442 	struct role_datum *role;
1443 	struct type_datum *typdatum;
1444 	struct user_datum *usrdatum;
1445 	char *scontextp, *p, oldc;
1446 	int rc = 0;
1447 
1448 	context_init(ctx);
1449 
1450 	/* Parse the security context. */
1451 
1452 	rc = -EINVAL;
1453 	scontextp = scontext;
1454 
1455 	/* Extract the user. */
1456 	p = scontextp;
1457 	while (*p && *p != ':')
1458 		p++;
1459 
1460 	if (*p == 0)
1461 		goto out;
1462 
1463 	*p++ = 0;
1464 
1465 	usrdatum = symtab_search(&pol->p_users, scontextp);
1466 	if (!usrdatum)
1467 		goto out;
1468 
1469 	ctx->user = usrdatum->value;
1470 
1471 	/* Extract role. */
1472 	scontextp = p;
1473 	while (*p && *p != ':')
1474 		p++;
1475 
1476 	if (*p == 0)
1477 		goto out;
1478 
1479 	*p++ = 0;
1480 
1481 	role = symtab_search(&pol->p_roles, scontextp);
1482 	if (!role)
1483 		goto out;
1484 	ctx->role = role->value;
1485 
1486 	/* Extract type. */
1487 	scontextp = p;
1488 	while (*p && *p != ':')
1489 		p++;
1490 	oldc = *p;
1491 	*p++ = 0;
1492 
1493 	typdatum = symtab_search(&pol->p_types, scontextp);
1494 	if (!typdatum || typdatum->attribute)
1495 		goto out;
1496 
1497 	ctx->type = typdatum->value;
1498 
1499 	rc = mls_context_to_sid(pol, oldc, p, ctx, sidtabp, def_sid);
1500 	if (rc)
1501 		goto out;
1502 
1503 	/* Check the validity of the new context. */
1504 	rc = -EINVAL;
1505 	if (!policydb_context_isvalid(pol, ctx))
1506 		goto out;
1507 	rc = 0;
1508 out:
1509 	if (rc)
1510 		context_destroy(ctx);
1511 	return rc;
1512 }
1513 
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)1514 static int security_context_to_sid_core(struct selinux_state *state,
1515 					const char *scontext, u32 scontext_len,
1516 					u32 *sid, u32 def_sid, gfp_t gfp_flags,
1517 					int force)
1518 {
1519 	struct selinux_policy *policy;
1520 	struct policydb *policydb;
1521 	struct sidtab *sidtab;
1522 	char *scontext2, *str = NULL;
1523 	struct context context;
1524 	int rc = 0;
1525 
1526 	/* An empty security context is never valid. */
1527 	if (!scontext_len)
1528 		return -EINVAL;
1529 
1530 	/* Copy the string to allow changes and ensure a NUL terminator */
1531 	scontext2 = kmemdup_nul(scontext, scontext_len, gfp_flags);
1532 	if (!scontext2)
1533 		return -ENOMEM;
1534 
1535 	if (!selinux_initialized(state)) {
1536 		int i;
1537 
1538 		for (i = 1; i < SECINITSID_NUM; i++) {
1539 			const char *s = initial_sid_to_string[i];
1540 
1541 			if (s && !strcmp(s, scontext2)) {
1542 				*sid = i;
1543 				goto out;
1544 			}
1545 		}
1546 		*sid = SECINITSID_KERNEL;
1547 		goto out;
1548 	}
1549 	*sid = SECSID_NULL;
1550 
1551 	if (force) {
1552 		/* Save another copy for storing in uninterpreted form */
1553 		rc = -ENOMEM;
1554 		str = kstrdup(scontext2, gfp_flags);
1555 		if (!str)
1556 			goto out;
1557 	}
1558 retry:
1559 	rcu_read_lock();
1560 	policy = rcu_dereference(state->policy);
1561 	policydb = &policy->policydb;
1562 	sidtab = policy->sidtab;
1563 	rc = string_to_context_struct(policydb, sidtab, scontext2,
1564 				      &context, def_sid);
1565 	if (rc == -EINVAL && force) {
1566 		context.str = str;
1567 		context.len = strlen(str) + 1;
1568 		str = NULL;
1569 	} else if (rc)
1570 		goto out_unlock;
1571 	rc = sidtab_context_to_sid(sidtab, &context, sid);
1572 	if (rc == -ESTALE) {
1573 		rcu_read_unlock();
1574 		if (context.str) {
1575 			str = context.str;
1576 			context.str = NULL;
1577 		}
1578 		context_destroy(&context);
1579 		goto retry;
1580 	}
1581 	context_destroy(&context);
1582 out_unlock:
1583 	rcu_read_unlock();
1584 out:
1585 	kfree(scontext2);
1586 	kfree(str);
1587 	return rc;
1588 }
1589 
1590 /**
1591  * security_context_to_sid - Obtain a SID for a given security context.
1592  * @state: SELinux state
1593  * @scontext: security context
1594  * @scontext_len: length in bytes
1595  * @sid: security identifier, SID
1596  * @gfp: context for the allocation
1597  *
1598  * Obtains a SID associated with the security context that
1599  * has the string representation specified by @scontext.
1600  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1601  * memory is available, or 0 on success.
1602  */
security_context_to_sid(struct selinux_state * state,const char * scontext,u32 scontext_len,u32 * sid,gfp_t gfp)1603 int security_context_to_sid(struct selinux_state *state,
1604 			    const char *scontext, u32 scontext_len, u32 *sid,
1605 			    gfp_t gfp)
1606 {
1607 	return security_context_to_sid_core(state, scontext, scontext_len,
1608 					    sid, SECSID_NULL, gfp, 0);
1609 }
1610 
security_context_str_to_sid(struct selinux_state * state,const char * scontext,u32 * sid,gfp_t gfp)1611 int security_context_str_to_sid(struct selinux_state *state,
1612 				const char *scontext, u32 *sid, gfp_t gfp)
1613 {
1614 	return security_context_to_sid(state, scontext, strlen(scontext),
1615 				       sid, gfp);
1616 }
1617 
1618 /**
1619  * security_context_to_sid_default - Obtain a SID for a given security context,
1620  * falling back to specified default if needed.
1621  *
1622  * @state: SELinux state
1623  * @scontext: security context
1624  * @scontext_len: length in bytes
1625  * @sid: security identifier, SID
1626  * @def_sid: default SID to assign on error
1627  * @gfp_flags: the allocator get-free-page (GFP) flags
1628  *
1629  * Obtains a SID associated with the security context that
1630  * has the string representation specified by @scontext.
1631  * The default SID is passed to the MLS layer to be used to allow
1632  * kernel labeling of the MLS field if the MLS field is not present
1633  * (for upgrading to MLS without full relabel).
1634  * Implicitly forces adding of the context even if it cannot be mapped yet.
1635  * Returns -%EINVAL if the context is invalid, -%ENOMEM if insufficient
1636  * memory is available, or 0 on success.
1637  */
security_context_to_sid_default(struct selinux_state * state,const char * scontext,u32 scontext_len,u32 * sid,u32 def_sid,gfp_t gfp_flags)1638 int security_context_to_sid_default(struct selinux_state *state,
1639 				    const char *scontext, u32 scontext_len,
1640 				    u32 *sid, u32 def_sid, gfp_t gfp_flags)
1641 {
1642 	return security_context_to_sid_core(state, scontext, scontext_len,
1643 					    sid, def_sid, gfp_flags, 1);
1644 }
1645 
security_context_to_sid_force(struct selinux_state * state,const char * scontext,u32 scontext_len,u32 * sid)1646 int security_context_to_sid_force(struct selinux_state *state,
1647 				  const char *scontext, u32 scontext_len,
1648 				  u32 *sid)
1649 {
1650 	return security_context_to_sid_core(state, scontext, scontext_len,
1651 					    sid, SECSID_NULL, GFP_KERNEL, 1);
1652 }
1653 
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)1654 static int compute_sid_handle_invalid_context(
1655 	struct selinux_state *state,
1656 	struct selinux_policy *policy,
1657 	struct sidtab_entry *sentry,
1658 	struct sidtab_entry *tentry,
1659 	u16 tclass,
1660 	struct context *newcontext)
1661 {
1662 	struct policydb *policydb = &policy->policydb;
1663 	struct sidtab *sidtab = policy->sidtab;
1664 	char *s = NULL, *t = NULL, *n = NULL;
1665 	u32 slen, tlen, nlen;
1666 	struct audit_buffer *ab;
1667 
1668 	if (sidtab_entry_to_string(policydb, sidtab, sentry, &s, &slen))
1669 		goto out;
1670 	if (sidtab_entry_to_string(policydb, sidtab, tentry, &t, &tlen))
1671 		goto out;
1672 	if (context_struct_to_string(policydb, newcontext, &n, &nlen))
1673 		goto out;
1674 	ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR);
1675 	if (!ab)
1676 		goto out;
1677 	audit_log_format(ab,
1678 			 "op=security_compute_sid invalid_context=");
1679 	/* no need to record the NUL with untrusted strings */
1680 	audit_log_n_untrustedstring(ab, n, nlen - 1);
1681 	audit_log_format(ab, " scontext=%s tcontext=%s tclass=%s",
1682 			 s, t, sym_name(policydb, SYM_CLASSES, tclass-1));
1683 	audit_log_end(ab);
1684 out:
1685 	kfree(s);
1686 	kfree(t);
1687 	kfree(n);
1688 	if (!enforcing_enabled(state))
1689 		return 0;
1690 	return -EACCES;
1691 }
1692 
filename_compute_type(struct policydb * policydb,struct context * newcontext,u32 stype,u32 ttype,u16 tclass,const char * objname)1693 static void filename_compute_type(struct policydb *policydb,
1694 				  struct context *newcontext,
1695 				  u32 stype, u32 ttype, u16 tclass,
1696 				  const char *objname)
1697 {
1698 	struct filename_trans_key ft;
1699 	struct filename_trans_datum *datum;
1700 
1701 	/*
1702 	 * Most filename trans rules are going to live in specific directories
1703 	 * like /dev or /var/run.  This bitmap will quickly skip rule searches
1704 	 * if the ttype does not contain any rules.
1705 	 */
1706 	if (!ebitmap_get_bit(&policydb->filename_trans_ttypes, ttype))
1707 		return;
1708 
1709 	ft.ttype = ttype;
1710 	ft.tclass = tclass;
1711 	ft.name = objname;
1712 
1713 	datum = policydb_filenametr_search(policydb, &ft);
1714 	while (datum) {
1715 		if (ebitmap_get_bit(&datum->stypes, stype - 1)) {
1716 			newcontext->type = datum->otype;
1717 			return;
1718 		}
1719 		datum = datum->next;
1720 	}
1721 }
1722 
security_compute_sid(struct selinux_state * state,u32 ssid,u32 tsid,u16 orig_tclass,u32 specified,const char * objname,u32 * out_sid,bool kern)1723 static int security_compute_sid(struct selinux_state *state,
1724 				u32 ssid,
1725 				u32 tsid,
1726 				u16 orig_tclass,
1727 				u32 specified,
1728 				const char *objname,
1729 				u32 *out_sid,
1730 				bool kern)
1731 {
1732 	struct selinux_policy *policy;
1733 	struct policydb *policydb;
1734 	struct sidtab *sidtab;
1735 	struct class_datum *cladatum;
1736 	struct context *scontext, *tcontext, newcontext;
1737 	struct sidtab_entry *sentry, *tentry;
1738 	struct avtab_key avkey;
1739 	struct avtab_datum *avdatum;
1740 	struct avtab_node *node;
1741 	u16 tclass;
1742 	int rc = 0;
1743 	bool sock;
1744 
1745 	if (!selinux_initialized(state)) {
1746 		switch (orig_tclass) {
1747 		case SECCLASS_PROCESS: /* kernel value */
1748 			*out_sid = ssid;
1749 			break;
1750 		default:
1751 			*out_sid = tsid;
1752 			break;
1753 		}
1754 		goto out;
1755 	}
1756 
1757 retry:
1758 	cladatum = NULL;
1759 	context_init(&newcontext);
1760 
1761 	rcu_read_lock();
1762 
1763 	policy = rcu_dereference(state->policy);
1764 
1765 	if (kern) {
1766 		tclass = unmap_class(&policy->map, orig_tclass);
1767 		sock = security_is_socket_class(orig_tclass);
1768 	} else {
1769 		tclass = orig_tclass;
1770 		sock = security_is_socket_class(map_class(&policy->map,
1771 							  tclass));
1772 	}
1773 
1774 	policydb = &policy->policydb;
1775 	sidtab = policy->sidtab;
1776 
1777 	sentry = sidtab_search_entry(sidtab, ssid);
1778 	if (!sentry) {
1779 		pr_err("SELinux: %s:  unrecognized SID %d\n",
1780 		       __func__, ssid);
1781 		rc = -EINVAL;
1782 		goto out_unlock;
1783 	}
1784 	tentry = sidtab_search_entry(sidtab, tsid);
1785 	if (!tentry) {
1786 		pr_err("SELinux: %s:  unrecognized SID %d\n",
1787 		       __func__, tsid);
1788 		rc = -EINVAL;
1789 		goto out_unlock;
1790 	}
1791 
1792 	scontext = &sentry->context;
1793 	tcontext = &tentry->context;
1794 
1795 	if (tclass && tclass <= policydb->p_classes.nprim)
1796 		cladatum = policydb->class_val_to_struct[tclass - 1];
1797 
1798 	/* Set the user identity. */
1799 	switch (specified) {
1800 	case AVTAB_TRANSITION:
1801 	case AVTAB_CHANGE:
1802 		if (cladatum && cladatum->default_user == DEFAULT_TARGET) {
1803 			newcontext.user = tcontext->user;
1804 		} else {
1805 			/* notice this gets both DEFAULT_SOURCE and unset */
1806 			/* Use the process user identity. */
1807 			newcontext.user = scontext->user;
1808 		}
1809 		break;
1810 	case AVTAB_MEMBER:
1811 		/* Use the related object owner. */
1812 		newcontext.user = tcontext->user;
1813 		break;
1814 	}
1815 
1816 	/* Set the role to default values. */
1817 	if (cladatum && cladatum->default_role == DEFAULT_SOURCE) {
1818 		newcontext.role = scontext->role;
1819 	} else if (cladatum && cladatum->default_role == DEFAULT_TARGET) {
1820 		newcontext.role = tcontext->role;
1821 	} else {
1822 		if ((tclass == policydb->process_class) || sock)
1823 			newcontext.role = scontext->role;
1824 		else
1825 			newcontext.role = OBJECT_R_VAL;
1826 	}
1827 
1828 	/* Set the type to default values. */
1829 	if (cladatum && cladatum->default_type == DEFAULT_SOURCE) {
1830 		newcontext.type = scontext->type;
1831 	} else if (cladatum && cladatum->default_type == DEFAULT_TARGET) {
1832 		newcontext.type = tcontext->type;
1833 	} else {
1834 		if ((tclass == policydb->process_class) || sock) {
1835 			/* Use the type of process. */
1836 			newcontext.type = scontext->type;
1837 		} else {
1838 			/* Use the type of the related object. */
1839 			newcontext.type = tcontext->type;
1840 		}
1841 	}
1842 
1843 	/* Look for a type transition/member/change rule. */
1844 	avkey.source_type = scontext->type;
1845 	avkey.target_type = tcontext->type;
1846 	avkey.target_class = tclass;
1847 	avkey.specified = specified;
1848 	avdatum = avtab_search(&policydb->te_avtab, &avkey);
1849 
1850 	/* If no permanent rule, also check for enabled conditional rules */
1851 	if (!avdatum) {
1852 		node = avtab_search_node(&policydb->te_cond_avtab, &avkey);
1853 		for (; node; node = avtab_search_node_next(node, specified)) {
1854 			if (node->key.specified & AVTAB_ENABLED) {
1855 				avdatum = &node->datum;
1856 				break;
1857 			}
1858 		}
1859 	}
1860 
1861 	if (avdatum) {
1862 		/* Use the type from the type transition/member/change rule. */
1863 		newcontext.type = avdatum->u.data;
1864 	}
1865 
1866 	/* if we have a objname this is a file trans check so check those rules */
1867 	if (objname)
1868 		filename_compute_type(policydb, &newcontext, scontext->type,
1869 				      tcontext->type, tclass, objname);
1870 
1871 	/* Check for class-specific changes. */
1872 	if (specified & AVTAB_TRANSITION) {
1873 		/* Look for a role transition rule. */
1874 		struct role_trans_datum *rtd;
1875 		struct role_trans_key rtk = {
1876 			.role = scontext->role,
1877 			.type = tcontext->type,
1878 			.tclass = tclass,
1879 		};
1880 
1881 		rtd = policydb_roletr_search(policydb, &rtk);
1882 		if (rtd)
1883 			newcontext.role = rtd->new_role;
1884 	}
1885 
1886 	/* Set the MLS attributes.
1887 	   This is done last because it may allocate memory. */
1888 	rc = mls_compute_sid(policydb, scontext, tcontext, tclass, specified,
1889 			     &newcontext, sock);
1890 	if (rc)
1891 		goto out_unlock;
1892 
1893 	/* Check the validity of the context. */
1894 	if (!policydb_context_isvalid(policydb, &newcontext)) {
1895 		rc = compute_sid_handle_invalid_context(state, policy, sentry,
1896 							tentry, tclass,
1897 							&newcontext);
1898 		if (rc)
1899 			goto out_unlock;
1900 	}
1901 	/* Obtain the sid for the context. */
1902 	rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid);
1903 	if (rc == -ESTALE) {
1904 		rcu_read_unlock();
1905 		context_destroy(&newcontext);
1906 		goto retry;
1907 	}
1908 out_unlock:
1909 	rcu_read_unlock();
1910 	context_destroy(&newcontext);
1911 out:
1912 	return rc;
1913 }
1914 
1915 /**
1916  * security_transition_sid - Compute the SID for a new subject/object.
1917  * @state: SELinux state
1918  * @ssid: source security identifier
1919  * @tsid: target security identifier
1920  * @tclass: target security class
1921  * @qstr: object name
1922  * @out_sid: security identifier for new subject/object
1923  *
1924  * Compute a SID to use for labeling a new subject or object in the
1925  * class @tclass based on a SID pair (@ssid, @tsid).
1926  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1927  * if insufficient memory is available, or %0 if the new SID was
1928  * computed successfully.
1929  */
security_transition_sid(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,const struct qstr * qstr,u32 * out_sid)1930 int security_transition_sid(struct selinux_state *state,
1931 			    u32 ssid, u32 tsid, u16 tclass,
1932 			    const struct qstr *qstr, u32 *out_sid)
1933 {
1934 	return security_compute_sid(state, ssid, tsid, tclass,
1935 				    AVTAB_TRANSITION,
1936 				    qstr ? qstr->name : NULL, out_sid, true);
1937 }
1938 
security_transition_sid_user(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,const char * objname,u32 * out_sid)1939 int security_transition_sid_user(struct selinux_state *state,
1940 				 u32 ssid, u32 tsid, u16 tclass,
1941 				 const char *objname, u32 *out_sid)
1942 {
1943 	return security_compute_sid(state, ssid, tsid, tclass,
1944 				    AVTAB_TRANSITION,
1945 				    objname, out_sid, false);
1946 }
1947 
1948 /**
1949  * security_member_sid - Compute the SID for member selection.
1950  * @state: SELinux state
1951  * @ssid: source security identifier
1952  * @tsid: target security identifier
1953  * @tclass: target security class
1954  * @out_sid: security identifier for selected member
1955  *
1956  * Compute a SID to use when selecting a member of a polyinstantiated
1957  * object of class @tclass based on a SID pair (@ssid, @tsid).
1958  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1959  * if insufficient memory is available, or %0 if the SID was
1960  * computed successfully.
1961  */
security_member_sid(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,u32 * out_sid)1962 int security_member_sid(struct selinux_state *state,
1963 			u32 ssid,
1964 			u32 tsid,
1965 			u16 tclass,
1966 			u32 *out_sid)
1967 {
1968 	return security_compute_sid(state, ssid, tsid, tclass,
1969 				    AVTAB_MEMBER, NULL,
1970 				    out_sid, false);
1971 }
1972 
1973 /**
1974  * security_change_sid - Compute the SID for object relabeling.
1975  * @state: SELinux state
1976  * @ssid: source security identifier
1977  * @tsid: target security identifier
1978  * @tclass: target security class
1979  * @out_sid: security identifier for selected member
1980  *
1981  * Compute a SID to use for relabeling an object of class @tclass
1982  * based on a SID pair (@ssid, @tsid).
1983  * Return -%EINVAL if any of the parameters are invalid, -%ENOMEM
1984  * if insufficient memory is available, or %0 if the SID was
1985  * computed successfully.
1986  */
security_change_sid(struct selinux_state * state,u32 ssid,u32 tsid,u16 tclass,u32 * out_sid)1987 int security_change_sid(struct selinux_state *state,
1988 			u32 ssid,
1989 			u32 tsid,
1990 			u16 tclass,
1991 			u32 *out_sid)
1992 {
1993 	return security_compute_sid(state,
1994 				    ssid, tsid, tclass, AVTAB_CHANGE, NULL,
1995 				    out_sid, false);
1996 }
1997 
convert_context_handle_invalid_context(struct selinux_state * state,struct policydb * policydb,struct context * context)1998 static inline int convert_context_handle_invalid_context(
1999 	struct selinux_state *state,
2000 	struct policydb *policydb,
2001 	struct context *context)
2002 {
2003 	char *s;
2004 	u32 len;
2005 
2006 	if (enforcing_enabled(state))
2007 		return -EINVAL;
2008 
2009 	if (!context_struct_to_string(policydb, context, &s, &len)) {
2010 		pr_warn("SELinux:  Context %s would be invalid if enforcing\n",
2011 			s);
2012 		kfree(s);
2013 	}
2014 	return 0;
2015 }
2016 
2017 /*
2018  * Convert the values in the security context
2019  * structure `oldc' from the values specified
2020  * in the policy `p->oldp' to the values specified
2021  * in the policy `p->newp', storing the new context
2022  * in `newc'.  Verify that the context is valid
2023  * under the new policy.
2024  */
convert_context(struct context * oldc,struct context * newc,void * p)2025 static int convert_context(struct context *oldc, struct context *newc, void *p)
2026 {
2027 	struct convert_context_args *args;
2028 	struct ocontext *oc;
2029 	struct role_datum *role;
2030 	struct type_datum *typdatum;
2031 	struct user_datum *usrdatum;
2032 	char *s;
2033 	u32 len;
2034 	int rc;
2035 
2036 	args = p;
2037 
2038 	if (oldc->str) {
2039 		s = kstrdup(oldc->str, GFP_KERNEL);
2040 		if (!s)
2041 			return -ENOMEM;
2042 
2043 		rc = string_to_context_struct(args->newp, NULL, s,
2044 					      newc, SECSID_NULL);
2045 		if (rc == -EINVAL) {
2046 			/*
2047 			 * Retain string representation for later mapping.
2048 			 *
2049 			 * IMPORTANT: We need to copy the contents of oldc->str
2050 			 * back into s again because string_to_context_struct()
2051 			 * may have garbled it.
2052 			 */
2053 			memcpy(s, oldc->str, oldc->len);
2054 			context_init(newc);
2055 			newc->str = s;
2056 			newc->len = oldc->len;
2057 			return 0;
2058 		}
2059 		kfree(s);
2060 		if (rc) {
2061 			/* Other error condition, e.g. ENOMEM. */
2062 			pr_err("SELinux:   Unable to map context %s, rc = %d.\n",
2063 			       oldc->str, -rc);
2064 			return rc;
2065 		}
2066 		pr_info("SELinux:  Context %s became valid (mapped).\n",
2067 			oldc->str);
2068 		return 0;
2069 	}
2070 
2071 	context_init(newc);
2072 
2073 	/* Convert the user. */
2074 	usrdatum = symtab_search(&args->newp->p_users,
2075 				 sym_name(args->oldp,
2076 					  SYM_USERS, oldc->user - 1));
2077 	if (!usrdatum)
2078 		goto bad;
2079 	newc->user = usrdatum->value;
2080 
2081 	/* Convert the role. */
2082 	role = symtab_search(&args->newp->p_roles,
2083 			     sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
2084 	if (!role)
2085 		goto bad;
2086 	newc->role = role->value;
2087 
2088 	/* Convert the type. */
2089 	typdatum = symtab_search(&args->newp->p_types,
2090 				 sym_name(args->oldp,
2091 					  SYM_TYPES, oldc->type - 1));
2092 	if (!typdatum)
2093 		goto bad;
2094 	newc->type = typdatum->value;
2095 
2096 	/* Convert the MLS fields if dealing with MLS policies */
2097 	if (args->oldp->mls_enabled && args->newp->mls_enabled) {
2098 		rc = mls_convert_context(args->oldp, args->newp, oldc, newc);
2099 		if (rc)
2100 			goto bad;
2101 	} else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
2102 		/*
2103 		 * Switching between non-MLS and MLS policy:
2104 		 * ensure that the MLS fields of the context for all
2105 		 * existing entries in the sidtab are filled in with a
2106 		 * suitable default value, likely taken from one of the
2107 		 * initial SIDs.
2108 		 */
2109 		oc = args->newp->ocontexts[OCON_ISID];
2110 		while (oc && oc->sid[0] != SECINITSID_UNLABELED)
2111 			oc = oc->next;
2112 		if (!oc) {
2113 			pr_err("SELinux:  unable to look up"
2114 				" the initial SIDs list\n");
2115 			goto bad;
2116 		}
2117 		rc = mls_range_set(newc, &oc->context[0].range);
2118 		if (rc)
2119 			goto bad;
2120 	}
2121 
2122 	/* Check the validity of the new context. */
2123 	if (!policydb_context_isvalid(args->newp, newc)) {
2124 		rc = convert_context_handle_invalid_context(args->state,
2125 							args->oldp,
2126 							oldc);
2127 		if (rc)
2128 			goto bad;
2129 	}
2130 
2131 	return 0;
2132 bad:
2133 	/* Map old representation to string and save it. */
2134 	rc = context_struct_to_string(args->oldp, oldc, &s, &len);
2135 	if (rc)
2136 		return rc;
2137 	context_destroy(newc);
2138 	newc->str = s;
2139 	newc->len = len;
2140 	pr_info("SELinux:  Context %s became invalid (unmapped).\n",
2141 		newc->str);
2142 	return 0;
2143 }
2144 
security_load_policycaps(struct selinux_state * state,struct selinux_policy * policy)2145 static void security_load_policycaps(struct selinux_state *state,
2146 				struct selinux_policy *policy)
2147 {
2148 	struct policydb *p;
2149 	unsigned int i;
2150 	struct ebitmap_node *node;
2151 
2152 	p = &policy->policydb;
2153 
2154 	for (i = 0; i < ARRAY_SIZE(state->policycap); i++)
2155 		WRITE_ONCE(state->policycap[i],
2156 			ebitmap_get_bit(&p->policycaps, i));
2157 
2158 	for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
2159 		pr_info("SELinux:  policy capability %s=%d\n",
2160 			selinux_policycap_names[i],
2161 			ebitmap_get_bit(&p->policycaps, i));
2162 
2163 	ebitmap_for_each_positive_bit(&p->policycaps, node, i) {
2164 		if (i >= ARRAY_SIZE(selinux_policycap_names))
2165 			pr_info("SELinux:  unknown policy capability %u\n",
2166 				i);
2167 	}
2168 }
2169 
2170 static int security_preserve_bools(struct selinux_policy *oldpolicy,
2171 				struct selinux_policy *newpolicy);
2172 
selinux_policy_free(struct selinux_policy * policy)2173 static void selinux_policy_free(struct selinux_policy *policy)
2174 {
2175 	if (!policy)
2176 		return;
2177 
2178 	sidtab_destroy(policy->sidtab);
2179 	kfree(policy->map.mapping);
2180 	policydb_destroy(&policy->policydb);
2181 	kfree(policy->sidtab);
2182 	kfree(policy);
2183 }
2184 
selinux_policy_cond_free(struct selinux_policy * policy)2185 static void selinux_policy_cond_free(struct selinux_policy *policy)
2186 {
2187 	cond_policydb_destroy_dup(&policy->policydb);
2188 	kfree(policy);
2189 }
2190 
selinux_policy_cancel(struct selinux_state * state,struct selinux_load_state * load_state)2191 void selinux_policy_cancel(struct selinux_state *state,
2192 			   struct selinux_load_state *load_state)
2193 {
2194 	struct selinux_policy *oldpolicy;
2195 
2196 	oldpolicy = rcu_dereference_protected(state->policy,
2197 					lockdep_is_held(&state->policy_mutex));
2198 
2199 	sidtab_cancel_convert(oldpolicy->sidtab);
2200 	selinux_policy_free(load_state->policy);
2201 	kfree(load_state->convert_data);
2202 }
2203 
selinux_notify_policy_change(struct selinux_state * state,u32 seqno)2204 static void selinux_notify_policy_change(struct selinux_state *state,
2205 					u32 seqno)
2206 {
2207 	/* Flush external caches and notify userspace of policy load */
2208 	avc_ss_reset(state->avc, seqno);
2209 	selnl_notify_policyload(seqno);
2210 	selinux_status_update_policyload(state, seqno);
2211 	selinux_netlbl_cache_invalidate();
2212 	selinux_xfrm_notify_policyload();
2213 	selinux_ima_measure_state_locked(state);
2214 }
2215 
selinux_policy_commit(struct selinux_state * state,struct selinux_load_state * load_state)2216 void selinux_policy_commit(struct selinux_state *state,
2217 			   struct selinux_load_state *load_state)
2218 {
2219 	struct selinux_policy *oldpolicy, *newpolicy = load_state->policy;
2220 	unsigned long flags;
2221 	u32 seqno;
2222 
2223 	oldpolicy = rcu_dereference_protected(state->policy,
2224 					lockdep_is_held(&state->policy_mutex));
2225 
2226 	/* If switching between different policy types, log MLS status */
2227 	if (oldpolicy) {
2228 		if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
2229 			pr_info("SELinux: Disabling MLS support...\n");
2230 		else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
2231 			pr_info("SELinux: Enabling MLS support...\n");
2232 	}
2233 
2234 	/* Set latest granting seqno for new policy. */
2235 	if (oldpolicy)
2236 		newpolicy->latest_granting = oldpolicy->latest_granting + 1;
2237 	else
2238 		newpolicy->latest_granting = 1;
2239 	seqno = newpolicy->latest_granting;
2240 
2241 	/* Install the new policy. */
2242 	if (oldpolicy) {
2243 		sidtab_freeze_begin(oldpolicy->sidtab, &flags);
2244 		rcu_assign_pointer(state->policy, newpolicy);
2245 		sidtab_freeze_end(oldpolicy->sidtab, &flags);
2246 	} else {
2247 		rcu_assign_pointer(state->policy, newpolicy);
2248 	}
2249 
2250 	/* Load the policycaps from the new policy */
2251 	security_load_policycaps(state, newpolicy);
2252 
2253 	if (!selinux_initialized(state)) {
2254 		/*
2255 		 * After first policy load, the security server is
2256 		 * marked as initialized and ready to handle requests and
2257 		 * any objects created prior to policy load are then labeled.
2258 		 */
2259 		selinux_mark_initialized(state);
2260 		selinux_complete_init();
2261 	}
2262 
2263 	/* Free the old policy */
2264 	synchronize_rcu();
2265 	selinux_policy_free(oldpolicy);
2266 	kfree(load_state->convert_data);
2267 
2268 	/* Notify others of the policy change */
2269 	selinux_notify_policy_change(state, seqno);
2270 }
2271 
2272 /**
2273  * security_load_policy - Load a security policy configuration.
2274  * @state: SELinux state
2275  * @data: binary policy data
2276  * @len: length of data in bytes
2277  * @load_state: policy load state
2278  *
2279  * Load a new set of security policy configuration data,
2280  * validate it and convert the SID table as necessary.
2281  * This function will flush the access vector cache after
2282  * loading the new policy.
2283  */
security_load_policy(struct selinux_state * state,void * data,size_t len,struct selinux_load_state * load_state)2284 int security_load_policy(struct selinux_state *state, void *data, size_t len,
2285 			 struct selinux_load_state *load_state)
2286 {
2287 	struct selinux_policy *newpolicy, *oldpolicy;
2288 	struct selinux_policy_convert_data *convert_data;
2289 	int rc = 0;
2290 	struct policy_file file = { data, len }, *fp = &file;
2291 
2292 	newpolicy = kzalloc(sizeof(*newpolicy), GFP_KERNEL);
2293 	if (!newpolicy)
2294 		return -ENOMEM;
2295 
2296 	newpolicy->sidtab = kzalloc(sizeof(*newpolicy->sidtab), GFP_KERNEL);
2297 	if (!newpolicy->sidtab) {
2298 		rc = -ENOMEM;
2299 		goto err_policy;
2300 	}
2301 
2302 	rc = policydb_read(&newpolicy->policydb, fp);
2303 	if (rc)
2304 		goto err_sidtab;
2305 
2306 	newpolicy->policydb.len = len;
2307 	rc = selinux_set_mapping(&newpolicy->policydb, secclass_map,
2308 				&newpolicy->map);
2309 	if (rc)
2310 		goto err_policydb;
2311 
2312 	rc = policydb_load_isids(&newpolicy->policydb, newpolicy->sidtab);
2313 	if (rc) {
2314 		pr_err("SELinux:  unable to load the initial SIDs\n");
2315 		goto err_mapping;
2316 	}
2317 
2318 	if (!selinux_initialized(state)) {
2319 		/* First policy load, so no need to preserve state from old policy */
2320 		load_state->policy = newpolicy;
2321 		load_state->convert_data = NULL;
2322 		return 0;
2323 	}
2324 
2325 	oldpolicy = rcu_dereference_protected(state->policy,
2326 					lockdep_is_held(&state->policy_mutex));
2327 
2328 	/* Preserve active boolean values from the old policy */
2329 	rc = security_preserve_bools(oldpolicy, newpolicy);
2330 	if (rc) {
2331 		pr_err("SELinux:  unable to preserve booleans\n");
2332 		goto err_free_isids;
2333 	}
2334 
2335 	convert_data = kmalloc(sizeof(*convert_data), GFP_KERNEL);
2336 	if (!convert_data) {
2337 		rc = -ENOMEM;
2338 		goto err_free_isids;
2339 	}
2340 
2341 	/*
2342 	 * Convert the internal representations of contexts
2343 	 * in the new SID table.
2344 	 */
2345 	convert_data->args.state = state;
2346 	convert_data->args.oldp = &oldpolicy->policydb;
2347 	convert_data->args.newp = &newpolicy->policydb;
2348 
2349 	convert_data->sidtab_params.func = convert_context;
2350 	convert_data->sidtab_params.args = &convert_data->args;
2351 	convert_data->sidtab_params.target = newpolicy->sidtab;
2352 
2353 	rc = sidtab_convert(oldpolicy->sidtab, &convert_data->sidtab_params);
2354 	if (rc) {
2355 		pr_err("SELinux:  unable to convert the internal"
2356 			" representation of contexts in the new SID"
2357 			" table\n");
2358 		goto err_free_convert_data;
2359 	}
2360 
2361 	load_state->policy = newpolicy;
2362 	load_state->convert_data = convert_data;
2363 	return 0;
2364 
2365 err_free_convert_data:
2366 	kfree(convert_data);
2367 err_free_isids:
2368 	sidtab_destroy(newpolicy->sidtab);
2369 err_mapping:
2370 	kfree(newpolicy->map.mapping);
2371 err_policydb:
2372 	policydb_destroy(&newpolicy->policydb);
2373 err_sidtab:
2374 	kfree(newpolicy->sidtab);
2375 err_policy:
2376 	kfree(newpolicy);
2377 
2378 	return rc;
2379 }
2380 
2381 /**
2382  * ocontext_to_sid - Helper to safely get sid for an ocontext
2383  * @sidtab: SID table
2384  * @c: ocontext structure
2385  * @index: index of the context entry (0 or 1)
2386  * @out_sid: pointer to the resulting SID value
2387  *
2388  * For all ocontexts except OCON_ISID the SID fields are populated
2389  * on-demand when needed. Since updating the SID value is an SMP-sensitive
2390  * operation, this helper must be used to do that safely.
2391  *
2392  * WARNING: This function may return -ESTALE, indicating that the caller
2393  * must retry the operation after re-acquiring the policy pointer!
2394  */
ocontext_to_sid(struct sidtab * sidtab,struct ocontext * c,size_t index,u32 * out_sid)2395 static int ocontext_to_sid(struct sidtab *sidtab, struct ocontext *c,
2396 			   size_t index, u32 *out_sid)
2397 {
2398 	int rc;
2399 	u32 sid;
2400 
2401 	/* Ensure the associated sidtab entry is visible to this thread. */
2402 	sid = smp_load_acquire(&c->sid[index]);
2403 	if (!sid) {
2404 		rc = sidtab_context_to_sid(sidtab, &c->context[index], &sid);
2405 		if (rc)
2406 			return rc;
2407 
2408 		/*
2409 		 * Ensure the new sidtab entry is visible to other threads
2410 		 * when they see the SID.
2411 		 */
2412 		smp_store_release(&c->sid[index], sid);
2413 	}
2414 	*out_sid = sid;
2415 	return 0;
2416 }
2417 
2418 /**
2419  * security_port_sid - Obtain the SID for a port.
2420  * @state: SELinux state
2421  * @protocol: protocol number
2422  * @port: port number
2423  * @out_sid: security identifier
2424  */
security_port_sid(struct selinux_state * state,u8 protocol,u16 port,u32 * out_sid)2425 int security_port_sid(struct selinux_state *state,
2426 		      u8 protocol, u16 port, u32 *out_sid)
2427 {
2428 	struct selinux_policy *policy;
2429 	struct policydb *policydb;
2430 	struct sidtab *sidtab;
2431 	struct ocontext *c;
2432 	int rc;
2433 
2434 	if (!selinux_initialized(state)) {
2435 		*out_sid = SECINITSID_PORT;
2436 		return 0;
2437 	}
2438 
2439 retry:
2440 	rc = 0;
2441 	rcu_read_lock();
2442 	policy = rcu_dereference(state->policy);
2443 	policydb = &policy->policydb;
2444 	sidtab = policy->sidtab;
2445 
2446 	c = policydb->ocontexts[OCON_PORT];
2447 	while (c) {
2448 		if (c->u.port.protocol == protocol &&
2449 		    c->u.port.low_port <= port &&
2450 		    c->u.port.high_port >= port)
2451 			break;
2452 		c = c->next;
2453 	}
2454 
2455 	if (c) {
2456 		rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2457 		if (rc == -ESTALE) {
2458 			rcu_read_unlock();
2459 			goto retry;
2460 		}
2461 		if (rc)
2462 			goto out;
2463 	} else {
2464 		*out_sid = SECINITSID_PORT;
2465 	}
2466 
2467 out:
2468 	rcu_read_unlock();
2469 	return rc;
2470 }
2471 
2472 /**
2473  * security_ib_pkey_sid - Obtain the SID for a pkey.
2474  * @state: SELinux state
2475  * @subnet_prefix: Subnet Prefix
2476  * @pkey_num: pkey number
2477  * @out_sid: security identifier
2478  */
security_ib_pkey_sid(struct selinux_state * state,u64 subnet_prefix,u16 pkey_num,u32 * out_sid)2479 int security_ib_pkey_sid(struct selinux_state *state,
2480 			 u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
2481 {
2482 	struct selinux_policy *policy;
2483 	struct policydb *policydb;
2484 	struct sidtab *sidtab;
2485 	struct ocontext *c;
2486 	int rc;
2487 
2488 	if (!selinux_initialized(state)) {
2489 		*out_sid = SECINITSID_UNLABELED;
2490 		return 0;
2491 	}
2492 
2493 retry:
2494 	rc = 0;
2495 	rcu_read_lock();
2496 	policy = rcu_dereference(state->policy);
2497 	policydb = &policy->policydb;
2498 	sidtab = policy->sidtab;
2499 
2500 	c = policydb->ocontexts[OCON_IBPKEY];
2501 	while (c) {
2502 		if (c->u.ibpkey.low_pkey <= pkey_num &&
2503 		    c->u.ibpkey.high_pkey >= pkey_num &&
2504 		    c->u.ibpkey.subnet_prefix == subnet_prefix)
2505 			break;
2506 
2507 		c = c->next;
2508 	}
2509 
2510 	if (c) {
2511 		rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2512 		if (rc == -ESTALE) {
2513 			rcu_read_unlock();
2514 			goto retry;
2515 		}
2516 		if (rc)
2517 			goto out;
2518 	} else
2519 		*out_sid = SECINITSID_UNLABELED;
2520 
2521 out:
2522 	rcu_read_unlock();
2523 	return rc;
2524 }
2525 
2526 /**
2527  * security_ib_endport_sid - Obtain the SID for a subnet management interface.
2528  * @state: SELinux state
2529  * @dev_name: device name
2530  * @port_num: port number
2531  * @out_sid: security identifier
2532  */
security_ib_endport_sid(struct selinux_state * state,const char * dev_name,u8 port_num,u32 * out_sid)2533 int security_ib_endport_sid(struct selinux_state *state,
2534 			    const char *dev_name, u8 port_num, u32 *out_sid)
2535 {
2536 	struct selinux_policy *policy;
2537 	struct policydb *policydb;
2538 	struct sidtab *sidtab;
2539 	struct ocontext *c;
2540 	int rc;
2541 
2542 	if (!selinux_initialized(state)) {
2543 		*out_sid = SECINITSID_UNLABELED;
2544 		return 0;
2545 	}
2546 
2547 retry:
2548 	rc = 0;
2549 	rcu_read_lock();
2550 	policy = rcu_dereference(state->policy);
2551 	policydb = &policy->policydb;
2552 	sidtab = policy->sidtab;
2553 
2554 	c = policydb->ocontexts[OCON_IBENDPORT];
2555 	while (c) {
2556 		if (c->u.ibendport.port == port_num &&
2557 		    !strncmp(c->u.ibendport.dev_name,
2558 			     dev_name,
2559 			     IB_DEVICE_NAME_MAX))
2560 			break;
2561 
2562 		c = c->next;
2563 	}
2564 
2565 	if (c) {
2566 		rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2567 		if (rc == -ESTALE) {
2568 			rcu_read_unlock();
2569 			goto retry;
2570 		}
2571 		if (rc)
2572 			goto out;
2573 	} else
2574 		*out_sid = SECINITSID_UNLABELED;
2575 
2576 out:
2577 	rcu_read_unlock();
2578 	return rc;
2579 }
2580 
2581 /**
2582  * security_netif_sid - Obtain the SID for a network interface.
2583  * @state: SELinux state
2584  * @name: interface name
2585  * @if_sid: interface SID
2586  */
security_netif_sid(struct selinux_state * state,char * name,u32 * if_sid)2587 int security_netif_sid(struct selinux_state *state,
2588 		       char *name, u32 *if_sid)
2589 {
2590 	struct selinux_policy *policy;
2591 	struct policydb *policydb;
2592 	struct sidtab *sidtab;
2593 	int rc;
2594 	struct ocontext *c;
2595 
2596 	if (!selinux_initialized(state)) {
2597 		*if_sid = SECINITSID_NETIF;
2598 		return 0;
2599 	}
2600 
2601 retry:
2602 	rc = 0;
2603 	rcu_read_lock();
2604 	policy = rcu_dereference(state->policy);
2605 	policydb = &policy->policydb;
2606 	sidtab = policy->sidtab;
2607 
2608 	c = policydb->ocontexts[OCON_NETIF];
2609 	while (c) {
2610 		if (strcmp(name, c->u.name) == 0)
2611 			break;
2612 		c = c->next;
2613 	}
2614 
2615 	if (c) {
2616 		rc = ocontext_to_sid(sidtab, c, 0, if_sid);
2617 		if (rc == -ESTALE) {
2618 			rcu_read_unlock();
2619 			goto retry;
2620 		}
2621 		if (rc)
2622 			goto out;
2623 	} else
2624 		*if_sid = SECINITSID_NETIF;
2625 
2626 out:
2627 	rcu_read_unlock();
2628 	return rc;
2629 }
2630 
match_ipv6_addrmask(u32 * input,u32 * addr,u32 * mask)2631 static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask)
2632 {
2633 	int i, fail = 0;
2634 
2635 	for (i = 0; i < 4; i++)
2636 		if (addr[i] != (input[i] & mask[i])) {
2637 			fail = 1;
2638 			break;
2639 		}
2640 
2641 	return !fail;
2642 }
2643 
2644 /**
2645  * security_node_sid - Obtain the SID for a node (host).
2646  * @state: SELinux state
2647  * @domain: communication domain aka address family
2648  * @addrp: address
2649  * @addrlen: address length in bytes
2650  * @out_sid: security identifier
2651  */
security_node_sid(struct selinux_state * state,u16 domain,void * addrp,u32 addrlen,u32 * out_sid)2652 int security_node_sid(struct selinux_state *state,
2653 		      u16 domain,
2654 		      void *addrp,
2655 		      u32 addrlen,
2656 		      u32 *out_sid)
2657 {
2658 	struct selinux_policy *policy;
2659 	struct policydb *policydb;
2660 	struct sidtab *sidtab;
2661 	int rc;
2662 	struct ocontext *c;
2663 
2664 	if (!selinux_initialized(state)) {
2665 		*out_sid = SECINITSID_NODE;
2666 		return 0;
2667 	}
2668 
2669 retry:
2670 	rcu_read_lock();
2671 	policy = rcu_dereference(state->policy);
2672 	policydb = &policy->policydb;
2673 	sidtab = policy->sidtab;
2674 
2675 	switch (domain) {
2676 	case AF_INET: {
2677 		u32 addr;
2678 
2679 		rc = -EINVAL;
2680 		if (addrlen != sizeof(u32))
2681 			goto out;
2682 
2683 		addr = *((u32 *)addrp);
2684 
2685 		c = policydb->ocontexts[OCON_NODE];
2686 		while (c) {
2687 			if (c->u.node.addr == (addr & c->u.node.mask))
2688 				break;
2689 			c = c->next;
2690 		}
2691 		break;
2692 	}
2693 
2694 	case AF_INET6:
2695 		rc = -EINVAL;
2696 		if (addrlen != sizeof(u64) * 2)
2697 			goto out;
2698 		c = policydb->ocontexts[OCON_NODE6];
2699 		while (c) {
2700 			if (match_ipv6_addrmask(addrp, c->u.node6.addr,
2701 						c->u.node6.mask))
2702 				break;
2703 			c = c->next;
2704 		}
2705 		break;
2706 
2707 	default:
2708 		rc = 0;
2709 		*out_sid = SECINITSID_NODE;
2710 		goto out;
2711 	}
2712 
2713 	if (c) {
2714 		rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2715 		if (rc == -ESTALE) {
2716 			rcu_read_unlock();
2717 			goto retry;
2718 		}
2719 		if (rc)
2720 			goto out;
2721 	} else {
2722 		*out_sid = SECINITSID_NODE;
2723 	}
2724 
2725 	rc = 0;
2726 out:
2727 	rcu_read_unlock();
2728 	return rc;
2729 }
2730 
2731 #define SIDS_NEL 25
2732 
2733 /**
2734  * security_get_user_sids - Obtain reachable SIDs for a user.
2735  * @state: SELinux state
2736  * @fromsid: starting SID
2737  * @username: username
2738  * @sids: array of reachable SIDs for user
2739  * @nel: number of elements in @sids
2740  *
2741  * Generate the set of SIDs for legal security contexts
2742  * for a given user that can be reached by @fromsid.
2743  * Set *@sids to point to a dynamically allocated
2744  * array containing the set of SIDs.  Set *@nel to the
2745  * number of elements in the array.
2746  */
2747 
security_get_user_sids(struct selinux_state * state,u32 fromsid,char * username,u32 ** sids,u32 * nel)2748 int security_get_user_sids(struct selinux_state *state,
2749 			   u32 fromsid,
2750 			   char *username,
2751 			   u32 **sids,
2752 			   u32 *nel)
2753 {
2754 	struct selinux_policy *policy;
2755 	struct policydb *policydb;
2756 	struct sidtab *sidtab;
2757 	struct context *fromcon, usercon;
2758 	u32 *mysids = NULL, *mysids2, sid;
2759 	u32 i, j, mynel, maxnel = SIDS_NEL;
2760 	struct user_datum *user;
2761 	struct role_datum *role;
2762 	struct ebitmap_node *rnode, *tnode;
2763 	int rc;
2764 
2765 	*sids = NULL;
2766 	*nel = 0;
2767 
2768 	if (!selinux_initialized(state))
2769 		return 0;
2770 
2771 	mysids = kcalloc(maxnel, sizeof(*mysids), GFP_KERNEL);
2772 	if (!mysids)
2773 		return -ENOMEM;
2774 
2775 retry:
2776 	mynel = 0;
2777 	rcu_read_lock();
2778 	policy = rcu_dereference(state->policy);
2779 	policydb = &policy->policydb;
2780 	sidtab = policy->sidtab;
2781 
2782 	context_init(&usercon);
2783 
2784 	rc = -EINVAL;
2785 	fromcon = sidtab_search(sidtab, fromsid);
2786 	if (!fromcon)
2787 		goto out_unlock;
2788 
2789 	rc = -EINVAL;
2790 	user = symtab_search(&policydb->p_users, username);
2791 	if (!user)
2792 		goto out_unlock;
2793 
2794 	usercon.user = user->value;
2795 
2796 	ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
2797 		role = policydb->role_val_to_struct[i];
2798 		usercon.role = i + 1;
2799 		ebitmap_for_each_positive_bit(&role->types, tnode, j) {
2800 			usercon.type = j + 1;
2801 
2802 			if (mls_setup_user_range(policydb, fromcon, user,
2803 						 &usercon))
2804 				continue;
2805 
2806 			rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
2807 			if (rc == -ESTALE) {
2808 				rcu_read_unlock();
2809 				goto retry;
2810 			}
2811 			if (rc)
2812 				goto out_unlock;
2813 			if (mynel < maxnel) {
2814 				mysids[mynel++] = sid;
2815 			} else {
2816 				rc = -ENOMEM;
2817 				maxnel += SIDS_NEL;
2818 				mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
2819 				if (!mysids2)
2820 					goto out_unlock;
2821 				memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
2822 				kfree(mysids);
2823 				mysids = mysids2;
2824 				mysids[mynel++] = sid;
2825 			}
2826 		}
2827 	}
2828 	rc = 0;
2829 out_unlock:
2830 	rcu_read_unlock();
2831 	if (rc || !mynel) {
2832 		kfree(mysids);
2833 		return rc;
2834 	}
2835 
2836 	rc = -ENOMEM;
2837 	mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
2838 	if (!mysids2) {
2839 		kfree(mysids);
2840 		return rc;
2841 	}
2842 	for (i = 0, j = 0; i < mynel; i++) {
2843 		struct av_decision dummy_avd;
2844 		rc = avc_has_perm_noaudit(state,
2845 					  fromsid, mysids[i],
2846 					  SECCLASS_PROCESS, /* kernel value */
2847 					  PROCESS__TRANSITION, AVC_STRICT,
2848 					  &dummy_avd);
2849 		if (!rc)
2850 			mysids2[j++] = mysids[i];
2851 		cond_resched();
2852 	}
2853 	kfree(mysids);
2854 	*sids = mysids2;
2855 	*nel = j;
2856 	return 0;
2857 }
2858 
2859 /**
2860  * __security_genfs_sid - Helper to obtain a SID for a file in a filesystem
2861  * @policy: policy
2862  * @fstype: filesystem type
2863  * @path: path from root of mount
2864  * @orig_sclass: file security class
2865  * @sid: SID for path
2866  *
2867  * Obtain a SID to use for a file in a filesystem that
2868  * cannot support xattr or use a fixed labeling behavior like
2869  * transition SIDs or task SIDs.
2870  *
2871  * WARNING: This function may return -ESTALE, indicating that the caller
2872  * must retry the operation after re-acquiring the policy pointer!
2873  */
__security_genfs_sid(struct selinux_policy * policy,const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2874 static inline int __security_genfs_sid(struct selinux_policy *policy,
2875 				       const char *fstype,
2876 				       const char *path,
2877 				       u16 orig_sclass,
2878 				       u32 *sid)
2879 {
2880 	struct policydb *policydb = &policy->policydb;
2881 	struct sidtab *sidtab = policy->sidtab;
2882 	int len;
2883 	u16 sclass;
2884 	struct genfs *genfs;
2885 	struct ocontext *c;
2886 	int cmp = 0;
2887 
2888 	while (path[0] == '/' && path[1] == '/')
2889 		path++;
2890 
2891 	sclass = unmap_class(&policy->map, orig_sclass);
2892 	*sid = SECINITSID_UNLABELED;
2893 
2894 	for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
2895 		cmp = strcmp(fstype, genfs->fstype);
2896 		if (cmp <= 0)
2897 			break;
2898 	}
2899 
2900 	if (!genfs || cmp)
2901 		return -ENOENT;
2902 
2903 	for (c = genfs->head; c; c = c->next) {
2904 		len = strlen(c->u.name);
2905 		if ((!c->v.sclass || sclass == c->v.sclass) &&
2906 		    (strncmp(c->u.name, path, len) == 0))
2907 			break;
2908 	}
2909 
2910 	if (!c)
2911 		return -ENOENT;
2912 
2913 	return ocontext_to_sid(sidtab, c, 0, sid);
2914 }
2915 
2916 /**
2917  * security_genfs_sid - Obtain a SID for a file in a filesystem
2918  * @state: SELinux state
2919  * @fstype: filesystem type
2920  * @path: path from root of mount
2921  * @orig_sclass: file security class
2922  * @sid: SID for path
2923  *
2924  * Acquire policy_rwlock before calling __security_genfs_sid() and release
2925  * it afterward.
2926  */
security_genfs_sid(struct selinux_state * state,const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2927 int security_genfs_sid(struct selinux_state *state,
2928 		       const char *fstype,
2929 		       const char *path,
2930 		       u16 orig_sclass,
2931 		       u32 *sid)
2932 {
2933 	struct selinux_policy *policy;
2934 	int retval;
2935 
2936 	if (!selinux_initialized(state)) {
2937 		*sid = SECINITSID_UNLABELED;
2938 		return 0;
2939 	}
2940 
2941 	do {
2942 		rcu_read_lock();
2943 		policy = rcu_dereference(state->policy);
2944 		retval = __security_genfs_sid(policy, fstype, path,
2945 					      orig_sclass, sid);
2946 		rcu_read_unlock();
2947 	} while (retval == -ESTALE);
2948 	return retval;
2949 }
2950 
selinux_policy_genfs_sid(struct selinux_policy * policy,const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2951 int selinux_policy_genfs_sid(struct selinux_policy *policy,
2952 			const char *fstype,
2953 			const char *path,
2954 			u16 orig_sclass,
2955 			u32 *sid)
2956 {
2957 	/* no lock required, policy is not yet accessible by other threads */
2958 	return __security_genfs_sid(policy, fstype, path, orig_sclass, sid);
2959 }
2960 
2961 /**
2962  * security_fs_use - Determine how to handle labeling for a filesystem.
2963  * @state: SELinux state
2964  * @sb: superblock in question
2965  */
security_fs_use(struct selinux_state * state,struct super_block * sb)2966 int security_fs_use(struct selinux_state *state, struct super_block *sb)
2967 {
2968 	struct selinux_policy *policy;
2969 	struct policydb *policydb;
2970 	struct sidtab *sidtab;
2971 	int rc;
2972 	struct ocontext *c;
2973 	struct superblock_security_struct *sbsec = selinux_superblock(sb);
2974 	const char *fstype = sb->s_type->name;
2975 
2976 	if (!selinux_initialized(state)) {
2977 		sbsec->behavior = SECURITY_FS_USE_NONE;
2978 		sbsec->sid = SECINITSID_UNLABELED;
2979 		return 0;
2980 	}
2981 
2982 retry:
2983 	rcu_read_lock();
2984 	policy = rcu_dereference(state->policy);
2985 	policydb = &policy->policydb;
2986 	sidtab = policy->sidtab;
2987 
2988 	c = policydb->ocontexts[OCON_FSUSE];
2989 	while (c) {
2990 		if (strcmp(fstype, c->u.name) == 0)
2991 			break;
2992 		c = c->next;
2993 	}
2994 
2995 	if (c) {
2996 		sbsec->behavior = c->v.behavior;
2997 		rc = ocontext_to_sid(sidtab, c, 0, &sbsec->sid);
2998 		if (rc == -ESTALE) {
2999 			rcu_read_unlock();
3000 			goto retry;
3001 		}
3002 		if (rc)
3003 			goto out;
3004 	} else {
3005 		rc = __security_genfs_sid(policy, fstype, "/",
3006 					SECCLASS_DIR, &sbsec->sid);
3007 		if (rc == -ESTALE) {
3008 			rcu_read_unlock();
3009 			goto retry;
3010 		}
3011 		if (rc) {
3012 			sbsec->behavior = SECURITY_FS_USE_NONE;
3013 			rc = 0;
3014 		} else {
3015 			sbsec->behavior = SECURITY_FS_USE_GENFS;
3016 		}
3017 	}
3018 
3019 out:
3020 	rcu_read_unlock();
3021 	return rc;
3022 }
3023 
security_get_bools(struct selinux_policy * policy,u32 * len,char *** names,int ** values)3024 int security_get_bools(struct selinux_policy *policy,
3025 		       u32 *len, char ***names, int **values)
3026 {
3027 	struct policydb *policydb;
3028 	u32 i;
3029 	int rc;
3030 
3031 	policydb = &policy->policydb;
3032 
3033 	*names = NULL;
3034 	*values = NULL;
3035 
3036 	rc = 0;
3037 	*len = policydb->p_bools.nprim;
3038 	if (!*len)
3039 		goto out;
3040 
3041 	rc = -ENOMEM;
3042 	*names = kcalloc(*len, sizeof(char *), GFP_ATOMIC);
3043 	if (!*names)
3044 		goto err;
3045 
3046 	rc = -ENOMEM;
3047 	*values = kcalloc(*len, sizeof(int), GFP_ATOMIC);
3048 	if (!*values)
3049 		goto err;
3050 
3051 	for (i = 0; i < *len; i++) {
3052 		(*values)[i] = policydb->bool_val_to_struct[i]->state;
3053 
3054 		rc = -ENOMEM;
3055 		(*names)[i] = kstrdup(sym_name(policydb, SYM_BOOLS, i),
3056 				      GFP_ATOMIC);
3057 		if (!(*names)[i])
3058 			goto err;
3059 	}
3060 	rc = 0;
3061 out:
3062 	return rc;
3063 err:
3064 	if (*names) {
3065 		for (i = 0; i < *len; i++)
3066 			kfree((*names)[i]);
3067 		kfree(*names);
3068 	}
3069 	kfree(*values);
3070 	*len = 0;
3071 	*names = NULL;
3072 	*values = NULL;
3073 	goto out;
3074 }
3075 
3076 
security_set_bools(struct selinux_state * state,u32 len,int * values)3077 int security_set_bools(struct selinux_state *state, u32 len, int *values)
3078 {
3079 	struct selinux_policy *newpolicy, *oldpolicy;
3080 	int rc;
3081 	u32 i, seqno = 0;
3082 
3083 	if (!selinux_initialized(state))
3084 		return -EINVAL;
3085 
3086 	oldpolicy = rcu_dereference_protected(state->policy,
3087 					lockdep_is_held(&state->policy_mutex));
3088 
3089 	/* Consistency check on number of booleans, should never fail */
3090 	if (WARN_ON(len != oldpolicy->policydb.p_bools.nprim))
3091 		return -EINVAL;
3092 
3093 	newpolicy = kmemdup(oldpolicy, sizeof(*newpolicy), GFP_KERNEL);
3094 	if (!newpolicy)
3095 		return -ENOMEM;
3096 
3097 	/*
3098 	 * Deep copy only the parts of the policydb that might be
3099 	 * modified as a result of changing booleans.
3100 	 */
3101 	rc = cond_policydb_dup(&newpolicy->policydb, &oldpolicy->policydb);
3102 	if (rc) {
3103 		kfree(newpolicy);
3104 		return -ENOMEM;
3105 	}
3106 
3107 	/* Update the boolean states in the copy */
3108 	for (i = 0; i < len; i++) {
3109 		int new_state = !!values[i];
3110 		int old_state = newpolicy->policydb.bool_val_to_struct[i]->state;
3111 
3112 		if (new_state != old_state) {
3113 			audit_log(audit_context(), GFP_ATOMIC,
3114 				AUDIT_MAC_CONFIG_CHANGE,
3115 				"bool=%s val=%d old_val=%d auid=%u ses=%u",
3116 				sym_name(&newpolicy->policydb, SYM_BOOLS, i),
3117 				new_state,
3118 				old_state,
3119 				from_kuid(&init_user_ns, audit_get_loginuid(current)),
3120 				audit_get_sessionid(current));
3121 			newpolicy->policydb.bool_val_to_struct[i]->state = new_state;
3122 		}
3123 	}
3124 
3125 	/* Re-evaluate the conditional rules in the copy */
3126 	evaluate_cond_nodes(&newpolicy->policydb);
3127 
3128 	/* Set latest granting seqno for new policy */
3129 	newpolicy->latest_granting = oldpolicy->latest_granting + 1;
3130 	seqno = newpolicy->latest_granting;
3131 
3132 	/* Install the new policy */
3133 	rcu_assign_pointer(state->policy, newpolicy);
3134 
3135 	/*
3136 	 * Free the conditional portions of the old policydb
3137 	 * that were copied for the new policy, and the oldpolicy
3138 	 * structure itself but not what it references.
3139 	 */
3140 	synchronize_rcu();
3141 	selinux_policy_cond_free(oldpolicy);
3142 
3143 	/* Notify others of the policy change */
3144 	selinux_notify_policy_change(state, seqno);
3145 	return 0;
3146 }
3147 
security_get_bool_value(struct selinux_state * state,u32 index)3148 int security_get_bool_value(struct selinux_state *state,
3149 			    u32 index)
3150 {
3151 	struct selinux_policy *policy;
3152 	struct policydb *policydb;
3153 	int rc;
3154 	u32 len;
3155 
3156 	if (!selinux_initialized(state))
3157 		return 0;
3158 
3159 	rcu_read_lock();
3160 	policy = rcu_dereference(state->policy);
3161 	policydb = &policy->policydb;
3162 
3163 	rc = -EFAULT;
3164 	len = policydb->p_bools.nprim;
3165 	if (index >= len)
3166 		goto out;
3167 
3168 	rc = policydb->bool_val_to_struct[index]->state;
3169 out:
3170 	rcu_read_unlock();
3171 	return rc;
3172 }
3173 
security_preserve_bools(struct selinux_policy * oldpolicy,struct selinux_policy * newpolicy)3174 static int security_preserve_bools(struct selinux_policy *oldpolicy,
3175 				struct selinux_policy *newpolicy)
3176 {
3177 	int rc, *bvalues = NULL;
3178 	char **bnames = NULL;
3179 	struct cond_bool_datum *booldatum;
3180 	u32 i, nbools = 0;
3181 
3182 	rc = security_get_bools(oldpolicy, &nbools, &bnames, &bvalues);
3183 	if (rc)
3184 		goto out;
3185 	for (i = 0; i < nbools; i++) {
3186 		booldatum = symtab_search(&newpolicy->policydb.p_bools,
3187 					bnames[i]);
3188 		if (booldatum)
3189 			booldatum->state = bvalues[i];
3190 	}
3191 	evaluate_cond_nodes(&newpolicy->policydb);
3192 
3193 out:
3194 	if (bnames) {
3195 		for (i = 0; i < nbools; i++)
3196 			kfree(bnames[i]);
3197 	}
3198 	kfree(bnames);
3199 	kfree(bvalues);
3200 	return rc;
3201 }
3202 
3203 /*
3204  * security_sid_mls_copy() - computes a new sid based on the given
3205  * sid and the mls portion of mls_sid.
3206  */
security_sid_mls_copy(struct selinux_state * state,u32 sid,u32 mls_sid,u32 * new_sid)3207 int security_sid_mls_copy(struct selinux_state *state,
3208 			  u32 sid, u32 mls_sid, u32 *new_sid)
3209 {
3210 	struct selinux_policy *policy;
3211 	struct policydb *policydb;
3212 	struct sidtab *sidtab;
3213 	struct context *context1;
3214 	struct context *context2;
3215 	struct context newcon;
3216 	char *s;
3217 	u32 len;
3218 	int rc;
3219 
3220 	if (!selinux_initialized(state)) {
3221 		*new_sid = sid;
3222 		return 0;
3223 	}
3224 
3225 retry:
3226 	rc = 0;
3227 	context_init(&newcon);
3228 
3229 	rcu_read_lock();
3230 	policy = rcu_dereference(state->policy);
3231 	policydb = &policy->policydb;
3232 	sidtab = policy->sidtab;
3233 
3234 	if (!policydb->mls_enabled) {
3235 		*new_sid = sid;
3236 		goto out_unlock;
3237 	}
3238 
3239 	rc = -EINVAL;
3240 	context1 = sidtab_search(sidtab, sid);
3241 	if (!context1) {
3242 		pr_err("SELinux: %s:  unrecognized SID %d\n",
3243 			__func__, sid);
3244 		goto out_unlock;
3245 	}
3246 
3247 	rc = -EINVAL;
3248 	context2 = sidtab_search(sidtab, mls_sid);
3249 	if (!context2) {
3250 		pr_err("SELinux: %s:  unrecognized SID %d\n",
3251 			__func__, mls_sid);
3252 		goto out_unlock;
3253 	}
3254 
3255 	newcon.user = context1->user;
3256 	newcon.role = context1->role;
3257 	newcon.type = context1->type;
3258 	rc = mls_context_cpy(&newcon, context2);
3259 	if (rc)
3260 		goto out_unlock;
3261 
3262 	/* Check the validity of the new context. */
3263 	if (!policydb_context_isvalid(policydb, &newcon)) {
3264 		rc = convert_context_handle_invalid_context(state, policydb,
3265 							&newcon);
3266 		if (rc) {
3267 			if (!context_struct_to_string(policydb, &newcon, &s,
3268 						      &len)) {
3269 				struct audit_buffer *ab;
3270 
3271 				ab = audit_log_start(audit_context(),
3272 						     GFP_ATOMIC,
3273 						     AUDIT_SELINUX_ERR);
3274 				audit_log_format(ab,
3275 						 "op=security_sid_mls_copy invalid_context=");
3276 				/* don't record NUL with untrusted strings */
3277 				audit_log_n_untrustedstring(ab, s, len - 1);
3278 				audit_log_end(ab);
3279 				kfree(s);
3280 			}
3281 			goto out_unlock;
3282 		}
3283 	}
3284 	rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
3285 	if (rc == -ESTALE) {
3286 		rcu_read_unlock();
3287 		context_destroy(&newcon);
3288 		goto retry;
3289 	}
3290 out_unlock:
3291 	rcu_read_unlock();
3292 	context_destroy(&newcon);
3293 	return rc;
3294 }
3295 
3296 /**
3297  * security_net_peersid_resolve - Compare and resolve two network peer SIDs
3298  * @state: SELinux state
3299  * @nlbl_sid: NetLabel SID
3300  * @nlbl_type: NetLabel labeling protocol type
3301  * @xfrm_sid: XFRM SID
3302  * @peer_sid: network peer sid
3303  *
3304  * Description:
3305  * Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be
3306  * resolved into a single SID it is returned via @peer_sid and the function
3307  * returns zero.  Otherwise @peer_sid is set to SECSID_NULL and the function
3308  * returns a negative value.  A table summarizing the behavior is below:
3309  *
3310  *                                 | function return |      @sid
3311  *   ------------------------------+-----------------+-----------------
3312  *   no peer labels                |        0        |    SECSID_NULL
3313  *   single peer label             |        0        |    <peer_label>
3314  *   multiple, consistent labels   |        0        |    <peer_label>
3315  *   multiple, inconsistent labels |    -<errno>     |    SECSID_NULL
3316  *
3317  */
security_net_peersid_resolve(struct selinux_state * state,u32 nlbl_sid,u32 nlbl_type,u32 xfrm_sid,u32 * peer_sid)3318 int security_net_peersid_resolve(struct selinux_state *state,
3319 				 u32 nlbl_sid, u32 nlbl_type,
3320 				 u32 xfrm_sid,
3321 				 u32 *peer_sid)
3322 {
3323 	struct selinux_policy *policy;
3324 	struct policydb *policydb;
3325 	struct sidtab *sidtab;
3326 	int rc;
3327 	struct context *nlbl_ctx;
3328 	struct context *xfrm_ctx;
3329 
3330 	*peer_sid = SECSID_NULL;
3331 
3332 	/* handle the common (which also happens to be the set of easy) cases
3333 	 * right away, these two if statements catch everything involving a
3334 	 * single or absent peer SID/label */
3335 	if (xfrm_sid == SECSID_NULL) {
3336 		*peer_sid = nlbl_sid;
3337 		return 0;
3338 	}
3339 	/* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label
3340 	 * and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label
3341 	 * is present */
3342 	if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) {
3343 		*peer_sid = xfrm_sid;
3344 		return 0;
3345 	}
3346 
3347 	if (!selinux_initialized(state))
3348 		return 0;
3349 
3350 	rcu_read_lock();
3351 	policy = rcu_dereference(state->policy);
3352 	policydb = &policy->policydb;
3353 	sidtab = policy->sidtab;
3354 
3355 	/*
3356 	 * We don't need to check initialized here since the only way both
3357 	 * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
3358 	 * security server was initialized and state->initialized was true.
3359 	 */
3360 	if (!policydb->mls_enabled) {
3361 		rc = 0;
3362 		goto out;
3363 	}
3364 
3365 	rc = -EINVAL;
3366 	nlbl_ctx = sidtab_search(sidtab, nlbl_sid);
3367 	if (!nlbl_ctx) {
3368 		pr_err("SELinux: %s:  unrecognized SID %d\n",
3369 		       __func__, nlbl_sid);
3370 		goto out;
3371 	}
3372 	rc = -EINVAL;
3373 	xfrm_ctx = sidtab_search(sidtab, xfrm_sid);
3374 	if (!xfrm_ctx) {
3375 		pr_err("SELinux: %s:  unrecognized SID %d\n",
3376 		       __func__, xfrm_sid);
3377 		goto out;
3378 	}
3379 	rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES);
3380 	if (rc)
3381 		goto out;
3382 
3383 	/* at present NetLabel SIDs/labels really only carry MLS
3384 	 * information so if the MLS portion of the NetLabel SID
3385 	 * matches the MLS portion of the labeled XFRM SID/label
3386 	 * then pass along the XFRM SID as it is the most
3387 	 * expressive */
3388 	*peer_sid = xfrm_sid;
3389 out:
3390 	rcu_read_unlock();
3391 	return rc;
3392 }
3393 
get_classes_callback(void * k,void * d,void * args)3394 static int get_classes_callback(void *k, void *d, void *args)
3395 {
3396 	struct class_datum *datum = d;
3397 	char *name = k, **classes = args;
3398 	int value = datum->value - 1;
3399 
3400 	classes[value] = kstrdup(name, GFP_ATOMIC);
3401 	if (!classes[value])
3402 		return -ENOMEM;
3403 
3404 	return 0;
3405 }
3406 
security_get_classes(struct selinux_policy * policy,char *** classes,int * nclasses)3407 int security_get_classes(struct selinux_policy *policy,
3408 			 char ***classes, int *nclasses)
3409 {
3410 	struct policydb *policydb;
3411 	int rc;
3412 
3413 	policydb = &policy->policydb;
3414 
3415 	rc = -ENOMEM;
3416 	*nclasses = policydb->p_classes.nprim;
3417 	*classes = kcalloc(*nclasses, sizeof(**classes), GFP_ATOMIC);
3418 	if (!*classes)
3419 		goto out;
3420 
3421 	rc = hashtab_map(&policydb->p_classes.table, get_classes_callback,
3422 			 *classes);
3423 	if (rc) {
3424 		int i;
3425 		for (i = 0; i < *nclasses; i++)
3426 			kfree((*classes)[i]);
3427 		kfree(*classes);
3428 	}
3429 
3430 out:
3431 	return rc;
3432 }
3433 
get_permissions_callback(void * k,void * d,void * args)3434 static int get_permissions_callback(void *k, void *d, void *args)
3435 {
3436 	struct perm_datum *datum = d;
3437 	char *name = k, **perms = args;
3438 	int value = datum->value - 1;
3439 
3440 	perms[value] = kstrdup(name, GFP_ATOMIC);
3441 	if (!perms[value])
3442 		return -ENOMEM;
3443 
3444 	return 0;
3445 }
3446 
security_get_permissions(struct selinux_policy * policy,char * class,char *** perms,int * nperms)3447 int security_get_permissions(struct selinux_policy *policy,
3448 			     char *class, char ***perms, int *nperms)
3449 {
3450 	struct policydb *policydb;
3451 	int rc, i;
3452 	struct class_datum *match;
3453 
3454 	policydb = &policy->policydb;
3455 
3456 	rc = -EINVAL;
3457 	match = symtab_search(&policydb->p_classes, class);
3458 	if (!match) {
3459 		pr_err("SELinux: %s:  unrecognized class %s\n",
3460 			__func__, class);
3461 		goto out;
3462 	}
3463 
3464 	rc = -ENOMEM;
3465 	*nperms = match->permissions.nprim;
3466 	*perms = kcalloc(*nperms, sizeof(**perms), GFP_ATOMIC);
3467 	if (!*perms)
3468 		goto out;
3469 
3470 	if (match->comdatum) {
3471 		rc = hashtab_map(&match->comdatum->permissions.table,
3472 				 get_permissions_callback, *perms);
3473 		if (rc)
3474 			goto err;
3475 	}
3476 
3477 	rc = hashtab_map(&match->permissions.table, get_permissions_callback,
3478 			 *perms);
3479 	if (rc)
3480 		goto err;
3481 
3482 out:
3483 	return rc;
3484 
3485 err:
3486 	for (i = 0; i < *nperms; i++)
3487 		kfree((*perms)[i]);
3488 	kfree(*perms);
3489 	return rc;
3490 }
3491 
security_get_reject_unknown(struct selinux_state * state)3492 int security_get_reject_unknown(struct selinux_state *state)
3493 {
3494 	struct selinux_policy *policy;
3495 	int value;
3496 
3497 	if (!selinux_initialized(state))
3498 		return 0;
3499 
3500 	rcu_read_lock();
3501 	policy = rcu_dereference(state->policy);
3502 	value = policy->policydb.reject_unknown;
3503 	rcu_read_unlock();
3504 	return value;
3505 }
3506 
security_get_allow_unknown(struct selinux_state * state)3507 int security_get_allow_unknown(struct selinux_state *state)
3508 {
3509 	struct selinux_policy *policy;
3510 	int value;
3511 
3512 	if (!selinux_initialized(state))
3513 		return 0;
3514 
3515 	rcu_read_lock();
3516 	policy = rcu_dereference(state->policy);
3517 	value = policy->policydb.allow_unknown;
3518 	rcu_read_unlock();
3519 	return value;
3520 }
3521 
3522 /**
3523  * security_policycap_supported - Check for a specific policy capability
3524  * @state: SELinux state
3525  * @req_cap: capability
3526  *
3527  * Description:
3528  * This function queries the currently loaded policy to see if it supports the
3529  * capability specified by @req_cap.  Returns true (1) if the capability is
3530  * supported, false (0) if it isn't supported.
3531  *
3532  */
security_policycap_supported(struct selinux_state * state,unsigned int req_cap)3533 int security_policycap_supported(struct selinux_state *state,
3534 				 unsigned int req_cap)
3535 {
3536 	struct selinux_policy *policy;
3537 	int rc;
3538 
3539 	if (!selinux_initialized(state))
3540 		return 0;
3541 
3542 	rcu_read_lock();
3543 	policy = rcu_dereference(state->policy);
3544 	rc = ebitmap_get_bit(&policy->policydb.policycaps, req_cap);
3545 	rcu_read_unlock();
3546 
3547 	return rc;
3548 }
3549 
3550 struct selinux_audit_rule {
3551 	u32 au_seqno;
3552 	struct context au_ctxt;
3553 };
3554 
selinux_audit_rule_free(void * vrule)3555 void selinux_audit_rule_free(void *vrule)
3556 {
3557 	struct selinux_audit_rule *rule = vrule;
3558 
3559 	if (rule) {
3560 		context_destroy(&rule->au_ctxt);
3561 		kfree(rule);
3562 	}
3563 }
3564 
selinux_audit_rule_init(u32 field,u32 op,char * rulestr,void ** vrule)3565 int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
3566 {
3567 	struct selinux_state *state = &selinux_state;
3568 	struct selinux_policy *policy;
3569 	struct policydb *policydb;
3570 	struct selinux_audit_rule *tmprule;
3571 	struct role_datum *roledatum;
3572 	struct type_datum *typedatum;
3573 	struct user_datum *userdatum;
3574 	struct selinux_audit_rule **rule = (struct selinux_audit_rule **)vrule;
3575 	int rc = 0;
3576 
3577 	*rule = NULL;
3578 
3579 	if (!selinux_initialized(state))
3580 		return -EOPNOTSUPP;
3581 
3582 	switch (field) {
3583 	case AUDIT_SUBJ_USER:
3584 	case AUDIT_SUBJ_ROLE:
3585 	case AUDIT_SUBJ_TYPE:
3586 	case AUDIT_OBJ_USER:
3587 	case AUDIT_OBJ_ROLE:
3588 	case AUDIT_OBJ_TYPE:
3589 		/* only 'equals' and 'not equals' fit user, role, and type */
3590 		if (op != Audit_equal && op != Audit_not_equal)
3591 			return -EINVAL;
3592 		break;
3593 	case AUDIT_SUBJ_SEN:
3594 	case AUDIT_SUBJ_CLR:
3595 	case AUDIT_OBJ_LEV_LOW:
3596 	case AUDIT_OBJ_LEV_HIGH:
3597 		/* we do not allow a range, indicated by the presence of '-' */
3598 		if (strchr(rulestr, '-'))
3599 			return -EINVAL;
3600 		break;
3601 	default:
3602 		/* only the above fields are valid */
3603 		return -EINVAL;
3604 	}
3605 
3606 	tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
3607 	if (!tmprule)
3608 		return -ENOMEM;
3609 
3610 	context_init(&tmprule->au_ctxt);
3611 
3612 	rcu_read_lock();
3613 	policy = rcu_dereference(state->policy);
3614 	policydb = &policy->policydb;
3615 
3616 	tmprule->au_seqno = policy->latest_granting;
3617 
3618 	switch (field) {
3619 	case AUDIT_SUBJ_USER:
3620 	case AUDIT_OBJ_USER:
3621 		rc = -EINVAL;
3622 		userdatum = symtab_search(&policydb->p_users, rulestr);
3623 		if (!userdatum)
3624 			goto out;
3625 		tmprule->au_ctxt.user = userdatum->value;
3626 		break;
3627 	case AUDIT_SUBJ_ROLE:
3628 	case AUDIT_OBJ_ROLE:
3629 		rc = -EINVAL;
3630 		roledatum = symtab_search(&policydb->p_roles, rulestr);
3631 		if (!roledatum)
3632 			goto out;
3633 		tmprule->au_ctxt.role = roledatum->value;
3634 		break;
3635 	case AUDIT_SUBJ_TYPE:
3636 	case AUDIT_OBJ_TYPE:
3637 		rc = -EINVAL;
3638 		typedatum = symtab_search(&policydb->p_types, rulestr);
3639 		if (!typedatum)
3640 			goto out;
3641 		tmprule->au_ctxt.type = typedatum->value;
3642 		break;
3643 	case AUDIT_SUBJ_SEN:
3644 	case AUDIT_SUBJ_CLR:
3645 	case AUDIT_OBJ_LEV_LOW:
3646 	case AUDIT_OBJ_LEV_HIGH:
3647 		rc = mls_from_string(policydb, rulestr, &tmprule->au_ctxt,
3648 				     GFP_ATOMIC);
3649 		if (rc)
3650 			goto out;
3651 		break;
3652 	}
3653 	rc = 0;
3654 out:
3655 	rcu_read_unlock();
3656 
3657 	if (rc) {
3658 		selinux_audit_rule_free(tmprule);
3659 		tmprule = NULL;
3660 	}
3661 
3662 	*rule = tmprule;
3663 
3664 	return rc;
3665 }
3666 
3667 /* Check to see if the rule contains any selinux fields */
selinux_audit_rule_known(struct audit_krule * rule)3668 int selinux_audit_rule_known(struct audit_krule *rule)
3669 {
3670 	int i;
3671 
3672 	for (i = 0; i < rule->field_count; i++) {
3673 		struct audit_field *f = &rule->fields[i];
3674 		switch (f->type) {
3675 		case AUDIT_SUBJ_USER:
3676 		case AUDIT_SUBJ_ROLE:
3677 		case AUDIT_SUBJ_TYPE:
3678 		case AUDIT_SUBJ_SEN:
3679 		case AUDIT_SUBJ_CLR:
3680 		case AUDIT_OBJ_USER:
3681 		case AUDIT_OBJ_ROLE:
3682 		case AUDIT_OBJ_TYPE:
3683 		case AUDIT_OBJ_LEV_LOW:
3684 		case AUDIT_OBJ_LEV_HIGH:
3685 			return 1;
3686 		}
3687 	}
3688 
3689 	return 0;
3690 }
3691 
selinux_audit_rule_match(u32 sid,u32 field,u32 op,void * vrule)3692 int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
3693 {
3694 	struct selinux_state *state = &selinux_state;
3695 	struct selinux_policy *policy;
3696 	struct context *ctxt;
3697 	struct mls_level *level;
3698 	struct selinux_audit_rule *rule = vrule;
3699 	int match = 0;
3700 
3701 	if (unlikely(!rule)) {
3702 		WARN_ONCE(1, "selinux_audit_rule_match: missing rule\n");
3703 		return -ENOENT;
3704 	}
3705 
3706 	if (!selinux_initialized(state))
3707 		return 0;
3708 
3709 	rcu_read_lock();
3710 
3711 	policy = rcu_dereference(state->policy);
3712 
3713 	if (rule->au_seqno < policy->latest_granting) {
3714 		match = -ESTALE;
3715 		goto out;
3716 	}
3717 
3718 	ctxt = sidtab_search(policy->sidtab, sid);
3719 	if (unlikely(!ctxt)) {
3720 		WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
3721 			  sid);
3722 		match = -ENOENT;
3723 		goto out;
3724 	}
3725 
3726 	/* a field/op pair that is not caught here will simply fall through
3727 	   without a match */
3728 	switch (field) {
3729 	case AUDIT_SUBJ_USER:
3730 	case AUDIT_OBJ_USER:
3731 		switch (op) {
3732 		case Audit_equal:
3733 			match = (ctxt->user == rule->au_ctxt.user);
3734 			break;
3735 		case Audit_not_equal:
3736 			match = (ctxt->user != rule->au_ctxt.user);
3737 			break;
3738 		}
3739 		break;
3740 	case AUDIT_SUBJ_ROLE:
3741 	case AUDIT_OBJ_ROLE:
3742 		switch (op) {
3743 		case Audit_equal:
3744 			match = (ctxt->role == rule->au_ctxt.role);
3745 			break;
3746 		case Audit_not_equal:
3747 			match = (ctxt->role != rule->au_ctxt.role);
3748 			break;
3749 		}
3750 		break;
3751 	case AUDIT_SUBJ_TYPE:
3752 	case AUDIT_OBJ_TYPE:
3753 		switch (op) {
3754 		case Audit_equal:
3755 			match = (ctxt->type == rule->au_ctxt.type);
3756 			break;
3757 		case Audit_not_equal:
3758 			match = (ctxt->type != rule->au_ctxt.type);
3759 			break;
3760 		}
3761 		break;
3762 	case AUDIT_SUBJ_SEN:
3763 	case AUDIT_SUBJ_CLR:
3764 	case AUDIT_OBJ_LEV_LOW:
3765 	case AUDIT_OBJ_LEV_HIGH:
3766 		level = ((field == AUDIT_SUBJ_SEN ||
3767 			  field == AUDIT_OBJ_LEV_LOW) ?
3768 			 &ctxt->range.level[0] : &ctxt->range.level[1]);
3769 		switch (op) {
3770 		case Audit_equal:
3771 			match = mls_level_eq(&rule->au_ctxt.range.level[0],
3772 					     level);
3773 			break;
3774 		case Audit_not_equal:
3775 			match = !mls_level_eq(&rule->au_ctxt.range.level[0],
3776 					      level);
3777 			break;
3778 		case Audit_lt:
3779 			match = (mls_level_dom(&rule->au_ctxt.range.level[0],
3780 					       level) &&
3781 				 !mls_level_eq(&rule->au_ctxt.range.level[0],
3782 					       level));
3783 			break;
3784 		case Audit_le:
3785 			match = mls_level_dom(&rule->au_ctxt.range.level[0],
3786 					      level);
3787 			break;
3788 		case Audit_gt:
3789 			match = (mls_level_dom(level,
3790 					      &rule->au_ctxt.range.level[0]) &&
3791 				 !mls_level_eq(level,
3792 					       &rule->au_ctxt.range.level[0]));
3793 			break;
3794 		case Audit_ge:
3795 			match = mls_level_dom(level,
3796 					      &rule->au_ctxt.range.level[0]);
3797 			break;
3798 		}
3799 	}
3800 
3801 out:
3802 	rcu_read_unlock();
3803 	return match;
3804 }
3805 
aurule_avc_callback(u32 event)3806 static int aurule_avc_callback(u32 event)
3807 {
3808 	if (event == AVC_CALLBACK_RESET)
3809 		return audit_update_lsm_rules();
3810 	return 0;
3811 }
3812 
aurule_init(void)3813 static int __init aurule_init(void)
3814 {
3815 	int err;
3816 
3817 	err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET);
3818 	if (err)
3819 		panic("avc_add_callback() failed, error %d\n", err);
3820 
3821 	return err;
3822 }
3823 __initcall(aurule_init);
3824 
3825 #ifdef CONFIG_NETLABEL
3826 /**
3827  * security_netlbl_cache_add - Add an entry to the NetLabel cache
3828  * @secattr: the NetLabel packet security attributes
3829  * @sid: the SELinux SID
3830  *
3831  * Description:
3832  * Attempt to cache the context in @ctx, which was derived from the packet in
3833  * @skb, in the NetLabel subsystem cache.  This function assumes @secattr has
3834  * already been initialized.
3835  *
3836  */
security_netlbl_cache_add(struct netlbl_lsm_secattr * secattr,u32 sid)3837 static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
3838 				      u32 sid)
3839 {
3840 	u32 *sid_cache;
3841 
3842 	sid_cache = kmalloc(sizeof(*sid_cache), GFP_ATOMIC);
3843 	if (sid_cache == NULL)
3844 		return;
3845 	secattr->cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
3846 	if (secattr->cache == NULL) {
3847 		kfree(sid_cache);
3848 		return;
3849 	}
3850 
3851 	*sid_cache = sid;
3852 	secattr->cache->free = kfree;
3853 	secattr->cache->data = sid_cache;
3854 	secattr->flags |= NETLBL_SECATTR_CACHE;
3855 }
3856 
3857 /**
3858  * security_netlbl_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
3859  * @state: SELinux state
3860  * @secattr: the NetLabel packet security attributes
3861  * @sid: the SELinux SID
3862  *
3863  * Description:
3864  * Convert the given NetLabel security attributes in @secattr into a
3865  * SELinux SID.  If the @secattr field does not contain a full SELinux
3866  * SID/context then use SECINITSID_NETMSG as the foundation.  If possible the
3867  * 'cache' field of @secattr is set and the CACHE flag is set; this is to
3868  * allow the @secattr to be used by NetLabel to cache the secattr to SID
3869  * conversion for future lookups.  Returns zero on success, negative values on
3870  * failure.
3871  *
3872  */
security_netlbl_secattr_to_sid(struct selinux_state * state,struct netlbl_lsm_secattr * secattr,u32 * sid)3873 int security_netlbl_secattr_to_sid(struct selinux_state *state,
3874 				   struct netlbl_lsm_secattr *secattr,
3875 				   u32 *sid)
3876 {
3877 	struct selinux_policy *policy;
3878 	struct policydb *policydb;
3879 	struct sidtab *sidtab;
3880 	int rc;
3881 	struct context *ctx;
3882 	struct context ctx_new;
3883 
3884 	if (!selinux_initialized(state)) {
3885 		*sid = SECSID_NULL;
3886 		return 0;
3887 	}
3888 
3889 retry:
3890 	rc = 0;
3891 	rcu_read_lock();
3892 	policy = rcu_dereference(state->policy);
3893 	policydb = &policy->policydb;
3894 	sidtab = policy->sidtab;
3895 
3896 	if (secattr->flags & NETLBL_SECATTR_CACHE)
3897 		*sid = *(u32 *)secattr->cache->data;
3898 	else if (secattr->flags & NETLBL_SECATTR_SECID)
3899 		*sid = secattr->attr.secid;
3900 	else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
3901 		rc = -EIDRM;
3902 		ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
3903 		if (ctx == NULL)
3904 			goto out;
3905 
3906 		context_init(&ctx_new);
3907 		ctx_new.user = ctx->user;
3908 		ctx_new.role = ctx->role;
3909 		ctx_new.type = ctx->type;
3910 		mls_import_netlbl_lvl(policydb, &ctx_new, secattr);
3911 		if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
3912 			rc = mls_import_netlbl_cat(policydb, &ctx_new, secattr);
3913 			if (rc)
3914 				goto out;
3915 		}
3916 		rc = -EIDRM;
3917 		if (!mls_context_isvalid(policydb, &ctx_new)) {
3918 			ebitmap_destroy(&ctx_new.range.level[0].cat);
3919 			goto out;
3920 		}
3921 
3922 		rc = sidtab_context_to_sid(sidtab, &ctx_new, sid);
3923 		ebitmap_destroy(&ctx_new.range.level[0].cat);
3924 		if (rc == -ESTALE) {
3925 			rcu_read_unlock();
3926 			goto retry;
3927 		}
3928 		if (rc)
3929 			goto out;
3930 
3931 		security_netlbl_cache_add(secattr, *sid);
3932 	} else
3933 		*sid = SECSID_NULL;
3934 
3935 out:
3936 	rcu_read_unlock();
3937 	return rc;
3938 }
3939 
3940 /**
3941  * security_netlbl_sid_to_secattr - Convert a SELinux SID to a NetLabel secattr
3942  * @state: SELinux state
3943  * @sid: the SELinux SID
3944  * @secattr: the NetLabel packet security attributes
3945  *
3946  * Description:
3947  * Convert the given SELinux SID in @sid into a NetLabel security attribute.
3948  * Returns zero on success, negative values on failure.
3949  *
3950  */
security_netlbl_sid_to_secattr(struct selinux_state * state,u32 sid,struct netlbl_lsm_secattr * secattr)3951 int security_netlbl_sid_to_secattr(struct selinux_state *state,
3952 				   u32 sid, struct netlbl_lsm_secattr *secattr)
3953 {
3954 	struct selinux_policy *policy;
3955 	struct policydb *policydb;
3956 	int rc;
3957 	struct context *ctx;
3958 
3959 	if (!selinux_initialized(state))
3960 		return 0;
3961 
3962 	rcu_read_lock();
3963 	policy = rcu_dereference(state->policy);
3964 	policydb = &policy->policydb;
3965 
3966 	rc = -ENOENT;
3967 	ctx = sidtab_search(policy->sidtab, sid);
3968 	if (ctx == NULL)
3969 		goto out;
3970 
3971 	rc = -ENOMEM;
3972 	secattr->domain = kstrdup(sym_name(policydb, SYM_TYPES, ctx->type - 1),
3973 				  GFP_ATOMIC);
3974 	if (secattr->domain == NULL)
3975 		goto out;
3976 
3977 	secattr->attr.secid = sid;
3978 	secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
3979 	mls_export_netlbl_lvl(policydb, ctx, secattr);
3980 	rc = mls_export_netlbl_cat(policydb, ctx, secattr);
3981 out:
3982 	rcu_read_unlock();
3983 	return rc;
3984 }
3985 #endif /* CONFIG_NETLABEL */
3986 
3987 /**
3988  * __security_read_policy - read the policy.
3989  * @policy: SELinux policy
3990  * @data: binary policy data
3991  * @len: length of data in bytes
3992  *
3993  */
__security_read_policy(struct selinux_policy * policy,void * data,size_t * len)3994 static int __security_read_policy(struct selinux_policy *policy,
3995 				  void *data, size_t *len)
3996 {
3997 	int rc;
3998 	struct policy_file fp;
3999 
4000 	fp.data = data;
4001 	fp.len = *len;
4002 
4003 	rc = policydb_write(&policy->policydb, &fp);
4004 	if (rc)
4005 		return rc;
4006 
4007 	*len = (unsigned long)fp.data - (unsigned long)data;
4008 	return 0;
4009 }
4010 
4011 /**
4012  * security_read_policy - read the policy.
4013  * @state: selinux_state
4014  * @data: binary policy data
4015  * @len: length of data in bytes
4016  *
4017  */
security_read_policy(struct selinux_state * state,void ** data,size_t * len)4018 int security_read_policy(struct selinux_state *state,
4019 			 void **data, size_t *len)
4020 {
4021 	struct selinux_policy *policy;
4022 
4023 	policy = rcu_dereference_protected(
4024 			state->policy, lockdep_is_held(&state->policy_mutex));
4025 	if (!policy)
4026 		return -EINVAL;
4027 
4028 	*len = policy->policydb.len;
4029 	*data = vmalloc_user(*len);
4030 	if (!*data)
4031 		return -ENOMEM;
4032 
4033 	return __security_read_policy(policy, *data, len);
4034 }
4035 
4036 /**
4037  * security_read_state_kernel - read the policy.
4038  * @state: selinux_state
4039  * @data: binary policy data
4040  * @len: length of data in bytes
4041  *
4042  * Allocates kernel memory for reading SELinux policy.
4043  * This function is for internal use only and should not
4044  * be used for returning data to user space.
4045  *
4046  * This function must be called with policy_mutex held.
4047  */
security_read_state_kernel(struct selinux_state * state,void ** data,size_t * len)4048 int security_read_state_kernel(struct selinux_state *state,
4049 			       void **data, size_t *len)
4050 {
4051 	int err;
4052 	struct selinux_policy *policy;
4053 
4054 	policy = rcu_dereference_protected(
4055 			state->policy, lockdep_is_held(&state->policy_mutex));
4056 	if (!policy)
4057 		return -EINVAL;
4058 
4059 	*len = policy->policydb.len;
4060 	*data = vmalloc(*len);
4061 	if (!*data)
4062 		return -ENOMEM;
4063 
4064 	err = __security_read_policy(policy, *data, len);
4065 	if (err) {
4066 		vfree(*data);
4067 		*data = NULL;
4068 		*len = 0;
4069 	}
4070 	return err;
4071 }
4072