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,gfp_t gfp_flags)2025 static int convert_context(struct context *oldc, struct context *newc, void *p,
2026 			   gfp_t gfp_flags)
2027 {
2028 	struct convert_context_args *args;
2029 	struct ocontext *oc;
2030 	struct role_datum *role;
2031 	struct type_datum *typdatum;
2032 	struct user_datum *usrdatum;
2033 	char *s;
2034 	u32 len;
2035 	int rc;
2036 
2037 	args = p;
2038 
2039 	if (oldc->str) {
2040 		s = kstrdup(oldc->str, gfp_flags);
2041 		if (!s)
2042 			return -ENOMEM;
2043 
2044 		rc = string_to_context_struct(args->newp, NULL, s,
2045 					      newc, SECSID_NULL);
2046 		if (rc == -EINVAL) {
2047 			/*
2048 			 * Retain string representation for later mapping.
2049 			 *
2050 			 * IMPORTANT: We need to copy the contents of oldc->str
2051 			 * back into s again because string_to_context_struct()
2052 			 * may have garbled it.
2053 			 */
2054 			memcpy(s, oldc->str, oldc->len);
2055 			context_init(newc);
2056 			newc->str = s;
2057 			newc->len = oldc->len;
2058 			return 0;
2059 		}
2060 		kfree(s);
2061 		if (rc) {
2062 			/* Other error condition, e.g. ENOMEM. */
2063 			pr_err("SELinux:   Unable to map context %s, rc = %d.\n",
2064 			       oldc->str, -rc);
2065 			return rc;
2066 		}
2067 		pr_info("SELinux:  Context %s became valid (mapped).\n",
2068 			oldc->str);
2069 		return 0;
2070 	}
2071 
2072 	context_init(newc);
2073 
2074 	/* Convert the user. */
2075 	usrdatum = symtab_search(&args->newp->p_users,
2076 				 sym_name(args->oldp,
2077 					  SYM_USERS, oldc->user - 1));
2078 	if (!usrdatum)
2079 		goto bad;
2080 	newc->user = usrdatum->value;
2081 
2082 	/* Convert the role. */
2083 	role = symtab_search(&args->newp->p_roles,
2084 			     sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
2085 	if (!role)
2086 		goto bad;
2087 	newc->role = role->value;
2088 
2089 	/* Convert the type. */
2090 	typdatum = symtab_search(&args->newp->p_types,
2091 				 sym_name(args->oldp,
2092 					  SYM_TYPES, oldc->type - 1));
2093 	if (!typdatum)
2094 		goto bad;
2095 	newc->type = typdatum->value;
2096 
2097 	/* Convert the MLS fields if dealing with MLS policies */
2098 	if (args->oldp->mls_enabled && args->newp->mls_enabled) {
2099 		rc = mls_convert_context(args->oldp, args->newp, oldc, newc);
2100 		if (rc)
2101 			goto bad;
2102 	} else if (!args->oldp->mls_enabled && args->newp->mls_enabled) {
2103 		/*
2104 		 * Switching between non-MLS and MLS policy:
2105 		 * ensure that the MLS fields of the context for all
2106 		 * existing entries in the sidtab are filled in with a
2107 		 * suitable default value, likely taken from one of the
2108 		 * initial SIDs.
2109 		 */
2110 		oc = args->newp->ocontexts[OCON_ISID];
2111 		while (oc && oc->sid[0] != SECINITSID_UNLABELED)
2112 			oc = oc->next;
2113 		if (!oc) {
2114 			pr_err("SELinux:  unable to look up"
2115 				" the initial SIDs list\n");
2116 			goto bad;
2117 		}
2118 		rc = mls_range_set(newc, &oc->context[0].range);
2119 		if (rc)
2120 			goto bad;
2121 	}
2122 
2123 	/* Check the validity of the new context. */
2124 	if (!policydb_context_isvalid(args->newp, newc)) {
2125 		rc = convert_context_handle_invalid_context(args->state,
2126 							args->oldp,
2127 							oldc);
2128 		if (rc)
2129 			goto bad;
2130 	}
2131 
2132 	return 0;
2133 bad:
2134 	/* Map old representation to string and save it. */
2135 	rc = context_struct_to_string(args->oldp, oldc, &s, &len);
2136 	if (rc)
2137 		return rc;
2138 	context_destroy(newc);
2139 	newc->str = s;
2140 	newc->len = len;
2141 	pr_info("SELinux:  Context %s became invalid (unmapped).\n",
2142 		newc->str);
2143 	return 0;
2144 }
2145 
security_load_policycaps(struct selinux_state * state,struct selinux_policy * policy)2146 static void security_load_policycaps(struct selinux_state *state,
2147 				struct selinux_policy *policy)
2148 {
2149 	struct policydb *p;
2150 	unsigned int i;
2151 	struct ebitmap_node *node;
2152 
2153 	p = &policy->policydb;
2154 
2155 	for (i = 0; i < ARRAY_SIZE(state->policycap); i++)
2156 		WRITE_ONCE(state->policycap[i],
2157 			ebitmap_get_bit(&p->policycaps, i));
2158 
2159 	for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
2160 		pr_info("SELinux:  policy capability %s=%d\n",
2161 			selinux_policycap_names[i],
2162 			ebitmap_get_bit(&p->policycaps, i));
2163 
2164 	ebitmap_for_each_positive_bit(&p->policycaps, node, i) {
2165 		if (i >= ARRAY_SIZE(selinux_policycap_names))
2166 			pr_info("SELinux:  unknown policy capability %u\n",
2167 				i);
2168 	}
2169 }
2170 
2171 static int security_preserve_bools(struct selinux_policy *oldpolicy,
2172 				struct selinux_policy *newpolicy);
2173 
selinux_policy_free(struct selinux_policy * policy)2174 static void selinux_policy_free(struct selinux_policy *policy)
2175 {
2176 	if (!policy)
2177 		return;
2178 
2179 	sidtab_destroy(policy->sidtab);
2180 	kfree(policy->map.mapping);
2181 	policydb_destroy(&policy->policydb);
2182 	kfree(policy->sidtab);
2183 	kfree(policy);
2184 }
2185 
selinux_policy_cond_free(struct selinux_policy * policy)2186 static void selinux_policy_cond_free(struct selinux_policy *policy)
2187 {
2188 	cond_policydb_destroy_dup(&policy->policydb);
2189 	kfree(policy);
2190 }
2191 
selinux_policy_cancel(struct selinux_state * state,struct selinux_load_state * load_state)2192 void selinux_policy_cancel(struct selinux_state *state,
2193 			   struct selinux_load_state *load_state)
2194 {
2195 	struct selinux_policy *oldpolicy;
2196 
2197 	oldpolicy = rcu_dereference_protected(state->policy,
2198 					lockdep_is_held(&state->policy_mutex));
2199 
2200 	sidtab_cancel_convert(oldpolicy->sidtab);
2201 	selinux_policy_free(load_state->policy);
2202 	kfree(load_state->convert_data);
2203 }
2204 
selinux_notify_policy_change(struct selinux_state * state,u32 seqno)2205 static void selinux_notify_policy_change(struct selinux_state *state,
2206 					u32 seqno)
2207 {
2208 	/* Flush external caches and notify userspace of policy load */
2209 	avc_ss_reset(state->avc, seqno);
2210 	selnl_notify_policyload(seqno);
2211 	selinux_status_update_policyload(state, seqno);
2212 	selinux_netlbl_cache_invalidate();
2213 	selinux_xfrm_notify_policyload();
2214 	selinux_ima_measure_state_locked(state);
2215 }
2216 
selinux_policy_commit(struct selinux_state * state,struct selinux_load_state * load_state)2217 void selinux_policy_commit(struct selinux_state *state,
2218 			   struct selinux_load_state *load_state)
2219 {
2220 	struct selinux_policy *oldpolicy, *newpolicy = load_state->policy;
2221 	unsigned long flags;
2222 	u32 seqno;
2223 
2224 	oldpolicy = rcu_dereference_protected(state->policy,
2225 					lockdep_is_held(&state->policy_mutex));
2226 
2227 	/* If switching between different policy types, log MLS status */
2228 	if (oldpolicy) {
2229 		if (oldpolicy->policydb.mls_enabled && !newpolicy->policydb.mls_enabled)
2230 			pr_info("SELinux: Disabling MLS support...\n");
2231 		else if (!oldpolicy->policydb.mls_enabled && newpolicy->policydb.mls_enabled)
2232 			pr_info("SELinux: Enabling MLS support...\n");
2233 	}
2234 
2235 	/* Set latest granting seqno for new policy. */
2236 	if (oldpolicy)
2237 		newpolicy->latest_granting = oldpolicy->latest_granting + 1;
2238 	else
2239 		newpolicy->latest_granting = 1;
2240 	seqno = newpolicy->latest_granting;
2241 
2242 	/* Install the new policy. */
2243 	if (oldpolicy) {
2244 		sidtab_freeze_begin(oldpolicy->sidtab, &flags);
2245 		rcu_assign_pointer(state->policy, newpolicy);
2246 		sidtab_freeze_end(oldpolicy->sidtab, &flags);
2247 	} else {
2248 		rcu_assign_pointer(state->policy, newpolicy);
2249 	}
2250 
2251 	/* Load the policycaps from the new policy */
2252 	security_load_policycaps(state, newpolicy);
2253 
2254 	if (!selinux_initialized(state)) {
2255 		/*
2256 		 * After first policy load, the security server is
2257 		 * marked as initialized and ready to handle requests and
2258 		 * any objects created prior to policy load are then labeled.
2259 		 */
2260 		selinux_mark_initialized(state);
2261 		selinux_complete_init();
2262 	}
2263 
2264 	/* Free the old policy */
2265 	synchronize_rcu();
2266 	selinux_policy_free(oldpolicy);
2267 	kfree(load_state->convert_data);
2268 
2269 	/* Notify others of the policy change */
2270 	selinux_notify_policy_change(state, seqno);
2271 }
2272 
2273 /**
2274  * security_load_policy - Load a security policy configuration.
2275  * @state: SELinux state
2276  * @data: binary policy data
2277  * @len: length of data in bytes
2278  * @load_state: policy load state
2279  *
2280  * Load a new set of security policy configuration data,
2281  * validate it and convert the SID table as necessary.
2282  * This function will flush the access vector cache after
2283  * loading the new policy.
2284  */
security_load_policy(struct selinux_state * state,void * data,size_t len,struct selinux_load_state * load_state)2285 int security_load_policy(struct selinux_state *state, void *data, size_t len,
2286 			 struct selinux_load_state *load_state)
2287 {
2288 	struct selinux_policy *newpolicy, *oldpolicy;
2289 	struct selinux_policy_convert_data *convert_data;
2290 	int rc = 0;
2291 	struct policy_file file = { data, len }, *fp = &file;
2292 
2293 	newpolicy = kzalloc(sizeof(*newpolicy), GFP_KERNEL);
2294 	if (!newpolicy)
2295 		return -ENOMEM;
2296 
2297 	newpolicy->sidtab = kzalloc(sizeof(*newpolicy->sidtab), GFP_KERNEL);
2298 	if (!newpolicy->sidtab) {
2299 		rc = -ENOMEM;
2300 		goto err_policy;
2301 	}
2302 
2303 	rc = policydb_read(&newpolicy->policydb, fp);
2304 	if (rc)
2305 		goto err_sidtab;
2306 
2307 	newpolicy->policydb.len = len;
2308 	rc = selinux_set_mapping(&newpolicy->policydb, secclass_map,
2309 				&newpolicy->map);
2310 	if (rc)
2311 		goto err_policydb;
2312 
2313 	rc = policydb_load_isids(&newpolicy->policydb, newpolicy->sidtab);
2314 	if (rc) {
2315 		pr_err("SELinux:  unable to load the initial SIDs\n");
2316 		goto err_mapping;
2317 	}
2318 
2319 	if (!selinux_initialized(state)) {
2320 		/* First policy load, so no need to preserve state from old policy */
2321 		load_state->policy = newpolicy;
2322 		load_state->convert_data = NULL;
2323 		return 0;
2324 	}
2325 
2326 	oldpolicy = rcu_dereference_protected(state->policy,
2327 					lockdep_is_held(&state->policy_mutex));
2328 
2329 	/* Preserve active boolean values from the old policy */
2330 	rc = security_preserve_bools(oldpolicy, newpolicy);
2331 	if (rc) {
2332 		pr_err("SELinux:  unable to preserve booleans\n");
2333 		goto err_free_isids;
2334 	}
2335 
2336 	convert_data = kmalloc(sizeof(*convert_data), GFP_KERNEL);
2337 	if (!convert_data) {
2338 		rc = -ENOMEM;
2339 		goto err_free_isids;
2340 	}
2341 
2342 	/*
2343 	 * Convert the internal representations of contexts
2344 	 * in the new SID table.
2345 	 */
2346 	convert_data->args.state = state;
2347 	convert_data->args.oldp = &oldpolicy->policydb;
2348 	convert_data->args.newp = &newpolicy->policydb;
2349 
2350 	convert_data->sidtab_params.func = convert_context;
2351 	convert_data->sidtab_params.args = &convert_data->args;
2352 	convert_data->sidtab_params.target = newpolicy->sidtab;
2353 
2354 	rc = sidtab_convert(oldpolicy->sidtab, &convert_data->sidtab_params);
2355 	if (rc) {
2356 		pr_err("SELinux:  unable to convert the internal"
2357 			" representation of contexts in the new SID"
2358 			" table\n");
2359 		goto err_free_convert_data;
2360 	}
2361 
2362 	load_state->policy = newpolicy;
2363 	load_state->convert_data = convert_data;
2364 	return 0;
2365 
2366 err_free_convert_data:
2367 	kfree(convert_data);
2368 err_free_isids:
2369 	sidtab_destroy(newpolicy->sidtab);
2370 err_mapping:
2371 	kfree(newpolicy->map.mapping);
2372 err_policydb:
2373 	policydb_destroy(&newpolicy->policydb);
2374 err_sidtab:
2375 	kfree(newpolicy->sidtab);
2376 err_policy:
2377 	kfree(newpolicy);
2378 
2379 	return rc;
2380 }
2381 
2382 /**
2383  * ocontext_to_sid - Helper to safely get sid for an ocontext
2384  * @sidtab: SID table
2385  * @c: ocontext structure
2386  * @index: index of the context entry (0 or 1)
2387  * @out_sid: pointer to the resulting SID value
2388  *
2389  * For all ocontexts except OCON_ISID the SID fields are populated
2390  * on-demand when needed. Since updating the SID value is an SMP-sensitive
2391  * operation, this helper must be used to do that safely.
2392  *
2393  * WARNING: This function may return -ESTALE, indicating that the caller
2394  * must retry the operation after re-acquiring the policy pointer!
2395  */
ocontext_to_sid(struct sidtab * sidtab,struct ocontext * c,size_t index,u32 * out_sid)2396 static int ocontext_to_sid(struct sidtab *sidtab, struct ocontext *c,
2397 			   size_t index, u32 *out_sid)
2398 {
2399 	int rc;
2400 	u32 sid;
2401 
2402 	/* Ensure the associated sidtab entry is visible to this thread. */
2403 	sid = smp_load_acquire(&c->sid[index]);
2404 	if (!sid) {
2405 		rc = sidtab_context_to_sid(sidtab, &c->context[index], &sid);
2406 		if (rc)
2407 			return rc;
2408 
2409 		/*
2410 		 * Ensure the new sidtab entry is visible to other threads
2411 		 * when they see the SID.
2412 		 */
2413 		smp_store_release(&c->sid[index], sid);
2414 	}
2415 	*out_sid = sid;
2416 	return 0;
2417 }
2418 
2419 /**
2420  * security_port_sid - Obtain the SID for a port.
2421  * @state: SELinux state
2422  * @protocol: protocol number
2423  * @port: port number
2424  * @out_sid: security identifier
2425  */
security_port_sid(struct selinux_state * state,u8 protocol,u16 port,u32 * out_sid)2426 int security_port_sid(struct selinux_state *state,
2427 		      u8 protocol, u16 port, u32 *out_sid)
2428 {
2429 	struct selinux_policy *policy;
2430 	struct policydb *policydb;
2431 	struct sidtab *sidtab;
2432 	struct ocontext *c;
2433 	int rc;
2434 
2435 	if (!selinux_initialized(state)) {
2436 		*out_sid = SECINITSID_PORT;
2437 		return 0;
2438 	}
2439 
2440 retry:
2441 	rc = 0;
2442 	rcu_read_lock();
2443 	policy = rcu_dereference(state->policy);
2444 	policydb = &policy->policydb;
2445 	sidtab = policy->sidtab;
2446 
2447 	c = policydb->ocontexts[OCON_PORT];
2448 	while (c) {
2449 		if (c->u.port.protocol == protocol &&
2450 		    c->u.port.low_port <= port &&
2451 		    c->u.port.high_port >= port)
2452 			break;
2453 		c = c->next;
2454 	}
2455 
2456 	if (c) {
2457 		rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2458 		if (rc == -ESTALE) {
2459 			rcu_read_unlock();
2460 			goto retry;
2461 		}
2462 		if (rc)
2463 			goto out;
2464 	} else {
2465 		*out_sid = SECINITSID_PORT;
2466 	}
2467 
2468 out:
2469 	rcu_read_unlock();
2470 	return rc;
2471 }
2472 
2473 /**
2474  * security_ib_pkey_sid - Obtain the SID for a pkey.
2475  * @state: SELinux state
2476  * @subnet_prefix: Subnet Prefix
2477  * @pkey_num: pkey number
2478  * @out_sid: security identifier
2479  */
security_ib_pkey_sid(struct selinux_state * state,u64 subnet_prefix,u16 pkey_num,u32 * out_sid)2480 int security_ib_pkey_sid(struct selinux_state *state,
2481 			 u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
2482 {
2483 	struct selinux_policy *policy;
2484 	struct policydb *policydb;
2485 	struct sidtab *sidtab;
2486 	struct ocontext *c;
2487 	int rc;
2488 
2489 	if (!selinux_initialized(state)) {
2490 		*out_sid = SECINITSID_UNLABELED;
2491 		return 0;
2492 	}
2493 
2494 retry:
2495 	rc = 0;
2496 	rcu_read_lock();
2497 	policy = rcu_dereference(state->policy);
2498 	policydb = &policy->policydb;
2499 	sidtab = policy->sidtab;
2500 
2501 	c = policydb->ocontexts[OCON_IBPKEY];
2502 	while (c) {
2503 		if (c->u.ibpkey.low_pkey <= pkey_num &&
2504 		    c->u.ibpkey.high_pkey >= pkey_num &&
2505 		    c->u.ibpkey.subnet_prefix == subnet_prefix)
2506 			break;
2507 
2508 		c = c->next;
2509 	}
2510 
2511 	if (c) {
2512 		rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2513 		if (rc == -ESTALE) {
2514 			rcu_read_unlock();
2515 			goto retry;
2516 		}
2517 		if (rc)
2518 			goto out;
2519 	} else
2520 		*out_sid = SECINITSID_UNLABELED;
2521 
2522 out:
2523 	rcu_read_unlock();
2524 	return rc;
2525 }
2526 
2527 /**
2528  * security_ib_endport_sid - Obtain the SID for a subnet management interface.
2529  * @state: SELinux state
2530  * @dev_name: device name
2531  * @port_num: port number
2532  * @out_sid: security identifier
2533  */
security_ib_endport_sid(struct selinux_state * state,const char * dev_name,u8 port_num,u32 * out_sid)2534 int security_ib_endport_sid(struct selinux_state *state,
2535 			    const char *dev_name, u8 port_num, u32 *out_sid)
2536 {
2537 	struct selinux_policy *policy;
2538 	struct policydb *policydb;
2539 	struct sidtab *sidtab;
2540 	struct ocontext *c;
2541 	int rc;
2542 
2543 	if (!selinux_initialized(state)) {
2544 		*out_sid = SECINITSID_UNLABELED;
2545 		return 0;
2546 	}
2547 
2548 retry:
2549 	rc = 0;
2550 	rcu_read_lock();
2551 	policy = rcu_dereference(state->policy);
2552 	policydb = &policy->policydb;
2553 	sidtab = policy->sidtab;
2554 
2555 	c = policydb->ocontexts[OCON_IBENDPORT];
2556 	while (c) {
2557 		if (c->u.ibendport.port == port_num &&
2558 		    !strncmp(c->u.ibendport.dev_name,
2559 			     dev_name,
2560 			     IB_DEVICE_NAME_MAX))
2561 			break;
2562 
2563 		c = c->next;
2564 	}
2565 
2566 	if (c) {
2567 		rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2568 		if (rc == -ESTALE) {
2569 			rcu_read_unlock();
2570 			goto retry;
2571 		}
2572 		if (rc)
2573 			goto out;
2574 	} else
2575 		*out_sid = SECINITSID_UNLABELED;
2576 
2577 out:
2578 	rcu_read_unlock();
2579 	return rc;
2580 }
2581 
2582 /**
2583  * security_netif_sid - Obtain the SID for a network interface.
2584  * @state: SELinux state
2585  * @name: interface name
2586  * @if_sid: interface SID
2587  */
security_netif_sid(struct selinux_state * state,char * name,u32 * if_sid)2588 int security_netif_sid(struct selinux_state *state,
2589 		       char *name, u32 *if_sid)
2590 {
2591 	struct selinux_policy *policy;
2592 	struct policydb *policydb;
2593 	struct sidtab *sidtab;
2594 	int rc;
2595 	struct ocontext *c;
2596 
2597 	if (!selinux_initialized(state)) {
2598 		*if_sid = SECINITSID_NETIF;
2599 		return 0;
2600 	}
2601 
2602 retry:
2603 	rc = 0;
2604 	rcu_read_lock();
2605 	policy = rcu_dereference(state->policy);
2606 	policydb = &policy->policydb;
2607 	sidtab = policy->sidtab;
2608 
2609 	c = policydb->ocontexts[OCON_NETIF];
2610 	while (c) {
2611 		if (strcmp(name, c->u.name) == 0)
2612 			break;
2613 		c = c->next;
2614 	}
2615 
2616 	if (c) {
2617 		rc = ocontext_to_sid(sidtab, c, 0, if_sid);
2618 		if (rc == -ESTALE) {
2619 			rcu_read_unlock();
2620 			goto retry;
2621 		}
2622 		if (rc)
2623 			goto out;
2624 	} else
2625 		*if_sid = SECINITSID_NETIF;
2626 
2627 out:
2628 	rcu_read_unlock();
2629 	return rc;
2630 }
2631 
match_ipv6_addrmask(u32 * input,u32 * addr,u32 * mask)2632 static int match_ipv6_addrmask(u32 *input, u32 *addr, u32 *mask)
2633 {
2634 	int i, fail = 0;
2635 
2636 	for (i = 0; i < 4; i++)
2637 		if (addr[i] != (input[i] & mask[i])) {
2638 			fail = 1;
2639 			break;
2640 		}
2641 
2642 	return !fail;
2643 }
2644 
2645 /**
2646  * security_node_sid - Obtain the SID for a node (host).
2647  * @state: SELinux state
2648  * @domain: communication domain aka address family
2649  * @addrp: address
2650  * @addrlen: address length in bytes
2651  * @out_sid: security identifier
2652  */
security_node_sid(struct selinux_state * state,u16 domain,void * addrp,u32 addrlen,u32 * out_sid)2653 int security_node_sid(struct selinux_state *state,
2654 		      u16 domain,
2655 		      void *addrp,
2656 		      u32 addrlen,
2657 		      u32 *out_sid)
2658 {
2659 	struct selinux_policy *policy;
2660 	struct policydb *policydb;
2661 	struct sidtab *sidtab;
2662 	int rc;
2663 	struct ocontext *c;
2664 
2665 	if (!selinux_initialized(state)) {
2666 		*out_sid = SECINITSID_NODE;
2667 		return 0;
2668 	}
2669 
2670 retry:
2671 	rcu_read_lock();
2672 	policy = rcu_dereference(state->policy);
2673 	policydb = &policy->policydb;
2674 	sidtab = policy->sidtab;
2675 
2676 	switch (domain) {
2677 	case AF_INET: {
2678 		u32 addr;
2679 
2680 		rc = -EINVAL;
2681 		if (addrlen != sizeof(u32))
2682 			goto out;
2683 
2684 		addr = *((u32 *)addrp);
2685 
2686 		c = policydb->ocontexts[OCON_NODE];
2687 		while (c) {
2688 			if (c->u.node.addr == (addr & c->u.node.mask))
2689 				break;
2690 			c = c->next;
2691 		}
2692 		break;
2693 	}
2694 
2695 	case AF_INET6:
2696 		rc = -EINVAL;
2697 		if (addrlen != sizeof(u64) * 2)
2698 			goto out;
2699 		c = policydb->ocontexts[OCON_NODE6];
2700 		while (c) {
2701 			if (match_ipv6_addrmask(addrp, c->u.node6.addr,
2702 						c->u.node6.mask))
2703 				break;
2704 			c = c->next;
2705 		}
2706 		break;
2707 
2708 	default:
2709 		rc = 0;
2710 		*out_sid = SECINITSID_NODE;
2711 		goto out;
2712 	}
2713 
2714 	if (c) {
2715 		rc = ocontext_to_sid(sidtab, c, 0, out_sid);
2716 		if (rc == -ESTALE) {
2717 			rcu_read_unlock();
2718 			goto retry;
2719 		}
2720 		if (rc)
2721 			goto out;
2722 	} else {
2723 		*out_sid = SECINITSID_NODE;
2724 	}
2725 
2726 	rc = 0;
2727 out:
2728 	rcu_read_unlock();
2729 	return rc;
2730 }
2731 
2732 #define SIDS_NEL 25
2733 
2734 /**
2735  * security_get_user_sids - Obtain reachable SIDs for a user.
2736  * @state: SELinux state
2737  * @fromsid: starting SID
2738  * @username: username
2739  * @sids: array of reachable SIDs for user
2740  * @nel: number of elements in @sids
2741  *
2742  * Generate the set of SIDs for legal security contexts
2743  * for a given user that can be reached by @fromsid.
2744  * Set *@sids to point to a dynamically allocated
2745  * array containing the set of SIDs.  Set *@nel to the
2746  * number of elements in the array.
2747  */
2748 
security_get_user_sids(struct selinux_state * state,u32 fromsid,char * username,u32 ** sids,u32 * nel)2749 int security_get_user_sids(struct selinux_state *state,
2750 			   u32 fromsid,
2751 			   char *username,
2752 			   u32 **sids,
2753 			   u32 *nel)
2754 {
2755 	struct selinux_policy *policy;
2756 	struct policydb *policydb;
2757 	struct sidtab *sidtab;
2758 	struct context *fromcon, usercon;
2759 	u32 *mysids = NULL, *mysids2, sid;
2760 	u32 i, j, mynel, maxnel = SIDS_NEL;
2761 	struct user_datum *user;
2762 	struct role_datum *role;
2763 	struct ebitmap_node *rnode, *tnode;
2764 	int rc;
2765 
2766 	*sids = NULL;
2767 	*nel = 0;
2768 
2769 	if (!selinux_initialized(state))
2770 		return 0;
2771 
2772 	mysids = kcalloc(maxnel, sizeof(*mysids), GFP_KERNEL);
2773 	if (!mysids)
2774 		return -ENOMEM;
2775 
2776 retry:
2777 	mynel = 0;
2778 	rcu_read_lock();
2779 	policy = rcu_dereference(state->policy);
2780 	policydb = &policy->policydb;
2781 	sidtab = policy->sidtab;
2782 
2783 	context_init(&usercon);
2784 
2785 	rc = -EINVAL;
2786 	fromcon = sidtab_search(sidtab, fromsid);
2787 	if (!fromcon)
2788 		goto out_unlock;
2789 
2790 	rc = -EINVAL;
2791 	user = symtab_search(&policydb->p_users, username);
2792 	if (!user)
2793 		goto out_unlock;
2794 
2795 	usercon.user = user->value;
2796 
2797 	ebitmap_for_each_positive_bit(&user->roles, rnode, i) {
2798 		role = policydb->role_val_to_struct[i];
2799 		usercon.role = i + 1;
2800 		ebitmap_for_each_positive_bit(&role->types, tnode, j) {
2801 			usercon.type = j + 1;
2802 
2803 			if (mls_setup_user_range(policydb, fromcon, user,
2804 						 &usercon))
2805 				continue;
2806 
2807 			rc = sidtab_context_to_sid(sidtab, &usercon, &sid);
2808 			if (rc == -ESTALE) {
2809 				rcu_read_unlock();
2810 				goto retry;
2811 			}
2812 			if (rc)
2813 				goto out_unlock;
2814 			if (mynel < maxnel) {
2815 				mysids[mynel++] = sid;
2816 			} else {
2817 				rc = -ENOMEM;
2818 				maxnel += SIDS_NEL;
2819 				mysids2 = kcalloc(maxnel, sizeof(*mysids2), GFP_ATOMIC);
2820 				if (!mysids2)
2821 					goto out_unlock;
2822 				memcpy(mysids2, mysids, mynel * sizeof(*mysids2));
2823 				kfree(mysids);
2824 				mysids = mysids2;
2825 				mysids[mynel++] = sid;
2826 			}
2827 		}
2828 	}
2829 	rc = 0;
2830 out_unlock:
2831 	rcu_read_unlock();
2832 	if (rc || !mynel) {
2833 		kfree(mysids);
2834 		return rc;
2835 	}
2836 
2837 	rc = -ENOMEM;
2838 	mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL);
2839 	if (!mysids2) {
2840 		kfree(mysids);
2841 		return rc;
2842 	}
2843 	for (i = 0, j = 0; i < mynel; i++) {
2844 		struct av_decision dummy_avd;
2845 		rc = avc_has_perm_noaudit(state,
2846 					  fromsid, mysids[i],
2847 					  SECCLASS_PROCESS, /* kernel value */
2848 					  PROCESS__TRANSITION, AVC_STRICT,
2849 					  &dummy_avd);
2850 		if (!rc)
2851 			mysids2[j++] = mysids[i];
2852 		cond_resched();
2853 	}
2854 	kfree(mysids);
2855 	*sids = mysids2;
2856 	*nel = j;
2857 	return 0;
2858 }
2859 
2860 /**
2861  * __security_genfs_sid - Helper to obtain a SID for a file in a filesystem
2862  * @policy: policy
2863  * @fstype: filesystem type
2864  * @path: path from root of mount
2865  * @orig_sclass: file security class
2866  * @sid: SID for path
2867  *
2868  * Obtain a SID to use for a file in a filesystem that
2869  * cannot support xattr or use a fixed labeling behavior like
2870  * transition SIDs or task SIDs.
2871  *
2872  * WARNING: This function may return -ESTALE, indicating that the caller
2873  * must retry the operation after re-acquiring the policy pointer!
2874  */
__security_genfs_sid(struct selinux_policy * policy,const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2875 static inline int __security_genfs_sid(struct selinux_policy *policy,
2876 				       const char *fstype,
2877 				       const char *path,
2878 				       u16 orig_sclass,
2879 				       u32 *sid)
2880 {
2881 	struct policydb *policydb = &policy->policydb;
2882 	struct sidtab *sidtab = policy->sidtab;
2883 	int len;
2884 	u16 sclass;
2885 	struct genfs *genfs;
2886 	struct ocontext *c;
2887 	int cmp = 0;
2888 
2889 	while (path[0] == '/' && path[1] == '/')
2890 		path++;
2891 
2892 	sclass = unmap_class(&policy->map, orig_sclass);
2893 	*sid = SECINITSID_UNLABELED;
2894 
2895 	for (genfs = policydb->genfs; genfs; genfs = genfs->next) {
2896 		cmp = strcmp(fstype, genfs->fstype);
2897 		if (cmp <= 0)
2898 			break;
2899 	}
2900 
2901 	if (!genfs || cmp)
2902 		return -ENOENT;
2903 
2904 	for (c = genfs->head; c; c = c->next) {
2905 		len = strlen(c->u.name);
2906 		if ((!c->v.sclass || sclass == c->v.sclass) &&
2907 		    (strncmp(c->u.name, path, len) == 0))
2908 			break;
2909 	}
2910 
2911 	if (!c)
2912 		return -ENOENT;
2913 
2914 	return ocontext_to_sid(sidtab, c, 0, sid);
2915 }
2916 
2917 /**
2918  * security_genfs_sid - Obtain a SID for a file in a filesystem
2919  * @state: SELinux state
2920  * @fstype: filesystem type
2921  * @path: path from root of mount
2922  * @orig_sclass: file security class
2923  * @sid: SID for path
2924  *
2925  * Acquire policy_rwlock before calling __security_genfs_sid() and release
2926  * it afterward.
2927  */
security_genfs_sid(struct selinux_state * state,const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2928 int security_genfs_sid(struct selinux_state *state,
2929 		       const char *fstype,
2930 		       const char *path,
2931 		       u16 orig_sclass,
2932 		       u32 *sid)
2933 {
2934 	struct selinux_policy *policy;
2935 	int retval;
2936 
2937 	if (!selinux_initialized(state)) {
2938 		*sid = SECINITSID_UNLABELED;
2939 		return 0;
2940 	}
2941 
2942 	do {
2943 		rcu_read_lock();
2944 		policy = rcu_dereference(state->policy);
2945 		retval = __security_genfs_sid(policy, fstype, path,
2946 					      orig_sclass, sid);
2947 		rcu_read_unlock();
2948 	} while (retval == -ESTALE);
2949 	return retval;
2950 }
2951 
selinux_policy_genfs_sid(struct selinux_policy * policy,const char * fstype,const char * path,u16 orig_sclass,u32 * sid)2952 int selinux_policy_genfs_sid(struct selinux_policy *policy,
2953 			const char *fstype,
2954 			const char *path,
2955 			u16 orig_sclass,
2956 			u32 *sid)
2957 {
2958 	/* no lock required, policy is not yet accessible by other threads */
2959 	return __security_genfs_sid(policy, fstype, path, orig_sclass, sid);
2960 }
2961 
2962 /**
2963  * security_fs_use - Determine how to handle labeling for a filesystem.
2964  * @state: SELinux state
2965  * @sb: superblock in question
2966  */
security_fs_use(struct selinux_state * state,struct super_block * sb)2967 int security_fs_use(struct selinux_state *state, struct super_block *sb)
2968 {
2969 	struct selinux_policy *policy;
2970 	struct policydb *policydb;
2971 	struct sidtab *sidtab;
2972 	int rc;
2973 	struct ocontext *c;
2974 	struct superblock_security_struct *sbsec = selinux_superblock(sb);
2975 	const char *fstype = sb->s_type->name;
2976 
2977 	if (!selinux_initialized(state)) {
2978 		sbsec->behavior = SECURITY_FS_USE_NONE;
2979 		sbsec->sid = SECINITSID_UNLABELED;
2980 		return 0;
2981 	}
2982 
2983 retry:
2984 	rcu_read_lock();
2985 	policy = rcu_dereference(state->policy);
2986 	policydb = &policy->policydb;
2987 	sidtab = policy->sidtab;
2988 
2989 	c = policydb->ocontexts[OCON_FSUSE];
2990 	while (c) {
2991 		if (strcmp(fstype, c->u.name) == 0)
2992 			break;
2993 		c = c->next;
2994 	}
2995 
2996 	if (c) {
2997 		sbsec->behavior = c->v.behavior;
2998 		rc = ocontext_to_sid(sidtab, c, 0, &sbsec->sid);
2999 		if (rc == -ESTALE) {
3000 			rcu_read_unlock();
3001 			goto retry;
3002 		}
3003 		if (rc)
3004 			goto out;
3005 	} else {
3006 		rc = __security_genfs_sid(policy, fstype, "/",
3007 					SECCLASS_DIR, &sbsec->sid);
3008 		if (rc == -ESTALE) {
3009 			rcu_read_unlock();
3010 			goto retry;
3011 		}
3012 		if (rc) {
3013 			sbsec->behavior = SECURITY_FS_USE_NONE;
3014 			rc = 0;
3015 		} else {
3016 			sbsec->behavior = SECURITY_FS_USE_GENFS;
3017 		}
3018 	}
3019 
3020 out:
3021 	rcu_read_unlock();
3022 	return rc;
3023 }
3024 
security_get_bools(struct selinux_policy * policy,u32 * len,char *** names,int ** values)3025 int security_get_bools(struct selinux_policy *policy,
3026 		       u32 *len, char ***names, int **values)
3027 {
3028 	struct policydb *policydb;
3029 	u32 i;
3030 	int rc;
3031 
3032 	policydb = &policy->policydb;
3033 
3034 	*names = NULL;
3035 	*values = NULL;
3036 
3037 	rc = 0;
3038 	*len = policydb->p_bools.nprim;
3039 	if (!*len)
3040 		goto out;
3041 
3042 	rc = -ENOMEM;
3043 	*names = kcalloc(*len, sizeof(char *), GFP_ATOMIC);
3044 	if (!*names)
3045 		goto err;
3046 
3047 	rc = -ENOMEM;
3048 	*values = kcalloc(*len, sizeof(int), GFP_ATOMIC);
3049 	if (!*values)
3050 		goto err;
3051 
3052 	for (i = 0; i < *len; i++) {
3053 		(*values)[i] = policydb->bool_val_to_struct[i]->state;
3054 
3055 		rc = -ENOMEM;
3056 		(*names)[i] = kstrdup(sym_name(policydb, SYM_BOOLS, i),
3057 				      GFP_ATOMIC);
3058 		if (!(*names)[i])
3059 			goto err;
3060 	}
3061 	rc = 0;
3062 out:
3063 	return rc;
3064 err:
3065 	if (*names) {
3066 		for (i = 0; i < *len; i++)
3067 			kfree((*names)[i]);
3068 		kfree(*names);
3069 	}
3070 	kfree(*values);
3071 	*len = 0;
3072 	*names = NULL;
3073 	*values = NULL;
3074 	goto out;
3075 }
3076 
3077 
security_set_bools(struct selinux_state * state,u32 len,int * values)3078 int security_set_bools(struct selinux_state *state, u32 len, int *values)
3079 {
3080 	struct selinux_policy *newpolicy, *oldpolicy;
3081 	int rc;
3082 	u32 i, seqno = 0;
3083 
3084 	if (!selinux_initialized(state))
3085 		return -EINVAL;
3086 
3087 	oldpolicy = rcu_dereference_protected(state->policy,
3088 					lockdep_is_held(&state->policy_mutex));
3089 
3090 	/* Consistency check on number of booleans, should never fail */
3091 	if (WARN_ON(len != oldpolicy->policydb.p_bools.nprim))
3092 		return -EINVAL;
3093 
3094 	newpolicy = kmemdup(oldpolicy, sizeof(*newpolicy), GFP_KERNEL);
3095 	if (!newpolicy)
3096 		return -ENOMEM;
3097 
3098 	/*
3099 	 * Deep copy only the parts of the policydb that might be
3100 	 * modified as a result of changing booleans.
3101 	 */
3102 	rc = cond_policydb_dup(&newpolicy->policydb, &oldpolicy->policydb);
3103 	if (rc) {
3104 		kfree(newpolicy);
3105 		return -ENOMEM;
3106 	}
3107 
3108 	/* Update the boolean states in the copy */
3109 	for (i = 0; i < len; i++) {
3110 		int new_state = !!values[i];
3111 		int old_state = newpolicy->policydb.bool_val_to_struct[i]->state;
3112 
3113 		if (new_state != old_state) {
3114 			audit_log(audit_context(), GFP_ATOMIC,
3115 				AUDIT_MAC_CONFIG_CHANGE,
3116 				"bool=%s val=%d old_val=%d auid=%u ses=%u",
3117 				sym_name(&newpolicy->policydb, SYM_BOOLS, i),
3118 				new_state,
3119 				old_state,
3120 				from_kuid(&init_user_ns, audit_get_loginuid(current)),
3121 				audit_get_sessionid(current));
3122 			newpolicy->policydb.bool_val_to_struct[i]->state = new_state;
3123 		}
3124 	}
3125 
3126 	/* Re-evaluate the conditional rules in the copy */
3127 	evaluate_cond_nodes(&newpolicy->policydb);
3128 
3129 	/* Set latest granting seqno for new policy */
3130 	newpolicy->latest_granting = oldpolicy->latest_granting + 1;
3131 	seqno = newpolicy->latest_granting;
3132 
3133 	/* Install the new policy */
3134 	rcu_assign_pointer(state->policy, newpolicy);
3135 
3136 	/*
3137 	 * Free the conditional portions of the old policydb
3138 	 * that were copied for the new policy, and the oldpolicy
3139 	 * structure itself but not what it references.
3140 	 */
3141 	synchronize_rcu();
3142 	selinux_policy_cond_free(oldpolicy);
3143 
3144 	/* Notify others of the policy change */
3145 	selinux_notify_policy_change(state, seqno);
3146 	return 0;
3147 }
3148 
security_get_bool_value(struct selinux_state * state,u32 index)3149 int security_get_bool_value(struct selinux_state *state,
3150 			    u32 index)
3151 {
3152 	struct selinux_policy *policy;
3153 	struct policydb *policydb;
3154 	int rc;
3155 	u32 len;
3156 
3157 	if (!selinux_initialized(state))
3158 		return 0;
3159 
3160 	rcu_read_lock();
3161 	policy = rcu_dereference(state->policy);
3162 	policydb = &policy->policydb;
3163 
3164 	rc = -EFAULT;
3165 	len = policydb->p_bools.nprim;
3166 	if (index >= len)
3167 		goto out;
3168 
3169 	rc = policydb->bool_val_to_struct[index]->state;
3170 out:
3171 	rcu_read_unlock();
3172 	return rc;
3173 }
3174 
security_preserve_bools(struct selinux_policy * oldpolicy,struct selinux_policy * newpolicy)3175 static int security_preserve_bools(struct selinux_policy *oldpolicy,
3176 				struct selinux_policy *newpolicy)
3177 {
3178 	int rc, *bvalues = NULL;
3179 	char **bnames = NULL;
3180 	struct cond_bool_datum *booldatum;
3181 	u32 i, nbools = 0;
3182 
3183 	rc = security_get_bools(oldpolicy, &nbools, &bnames, &bvalues);
3184 	if (rc)
3185 		goto out;
3186 	for (i = 0; i < nbools; i++) {
3187 		booldatum = symtab_search(&newpolicy->policydb.p_bools,
3188 					bnames[i]);
3189 		if (booldatum)
3190 			booldatum->state = bvalues[i];
3191 	}
3192 	evaluate_cond_nodes(&newpolicy->policydb);
3193 
3194 out:
3195 	if (bnames) {
3196 		for (i = 0; i < nbools; i++)
3197 			kfree(bnames[i]);
3198 	}
3199 	kfree(bnames);
3200 	kfree(bvalues);
3201 	return rc;
3202 }
3203 
3204 /*
3205  * security_sid_mls_copy() - computes a new sid based on the given
3206  * sid and the mls portion of mls_sid.
3207  */
security_sid_mls_copy(struct selinux_state * state,u32 sid,u32 mls_sid,u32 * new_sid)3208 int security_sid_mls_copy(struct selinux_state *state,
3209 			  u32 sid, u32 mls_sid, u32 *new_sid)
3210 {
3211 	struct selinux_policy *policy;
3212 	struct policydb *policydb;
3213 	struct sidtab *sidtab;
3214 	struct context *context1;
3215 	struct context *context2;
3216 	struct context newcon;
3217 	char *s;
3218 	u32 len;
3219 	int rc;
3220 
3221 	if (!selinux_initialized(state)) {
3222 		*new_sid = sid;
3223 		return 0;
3224 	}
3225 
3226 retry:
3227 	rc = 0;
3228 	context_init(&newcon);
3229 
3230 	rcu_read_lock();
3231 	policy = rcu_dereference(state->policy);
3232 	policydb = &policy->policydb;
3233 	sidtab = policy->sidtab;
3234 
3235 	if (!policydb->mls_enabled) {
3236 		*new_sid = sid;
3237 		goto out_unlock;
3238 	}
3239 
3240 	rc = -EINVAL;
3241 	context1 = sidtab_search(sidtab, sid);
3242 	if (!context1) {
3243 		pr_err("SELinux: %s:  unrecognized SID %d\n",
3244 			__func__, sid);
3245 		goto out_unlock;
3246 	}
3247 
3248 	rc = -EINVAL;
3249 	context2 = sidtab_search(sidtab, mls_sid);
3250 	if (!context2) {
3251 		pr_err("SELinux: %s:  unrecognized SID %d\n",
3252 			__func__, mls_sid);
3253 		goto out_unlock;
3254 	}
3255 
3256 	newcon.user = context1->user;
3257 	newcon.role = context1->role;
3258 	newcon.type = context1->type;
3259 	rc = mls_context_cpy(&newcon, context2);
3260 	if (rc)
3261 		goto out_unlock;
3262 
3263 	/* Check the validity of the new context. */
3264 	if (!policydb_context_isvalid(policydb, &newcon)) {
3265 		rc = convert_context_handle_invalid_context(state, policydb,
3266 							&newcon);
3267 		if (rc) {
3268 			if (!context_struct_to_string(policydb, &newcon, &s,
3269 						      &len)) {
3270 				struct audit_buffer *ab;
3271 
3272 				ab = audit_log_start(audit_context(),
3273 						     GFP_ATOMIC,
3274 						     AUDIT_SELINUX_ERR);
3275 				audit_log_format(ab,
3276 						 "op=security_sid_mls_copy invalid_context=");
3277 				/* don't record NUL with untrusted strings */
3278 				audit_log_n_untrustedstring(ab, s, len - 1);
3279 				audit_log_end(ab);
3280 				kfree(s);
3281 			}
3282 			goto out_unlock;
3283 		}
3284 	}
3285 	rc = sidtab_context_to_sid(sidtab, &newcon, new_sid);
3286 	if (rc == -ESTALE) {
3287 		rcu_read_unlock();
3288 		context_destroy(&newcon);
3289 		goto retry;
3290 	}
3291 out_unlock:
3292 	rcu_read_unlock();
3293 	context_destroy(&newcon);
3294 	return rc;
3295 }
3296 
3297 /**
3298  * security_net_peersid_resolve - Compare and resolve two network peer SIDs
3299  * @state: SELinux state
3300  * @nlbl_sid: NetLabel SID
3301  * @nlbl_type: NetLabel labeling protocol type
3302  * @xfrm_sid: XFRM SID
3303  * @peer_sid: network peer sid
3304  *
3305  * Description:
3306  * Compare the @nlbl_sid and @xfrm_sid values and if the two SIDs can be
3307  * resolved into a single SID it is returned via @peer_sid and the function
3308  * returns zero.  Otherwise @peer_sid is set to SECSID_NULL and the function
3309  * returns a negative value.  A table summarizing the behavior is below:
3310  *
3311  *                                 | function return |      @sid
3312  *   ------------------------------+-----------------+-----------------
3313  *   no peer labels                |        0        |    SECSID_NULL
3314  *   single peer label             |        0        |    <peer_label>
3315  *   multiple, consistent labels   |        0        |    <peer_label>
3316  *   multiple, inconsistent labels |    -<errno>     |    SECSID_NULL
3317  *
3318  */
security_net_peersid_resolve(struct selinux_state * state,u32 nlbl_sid,u32 nlbl_type,u32 xfrm_sid,u32 * peer_sid)3319 int security_net_peersid_resolve(struct selinux_state *state,
3320 				 u32 nlbl_sid, u32 nlbl_type,
3321 				 u32 xfrm_sid,
3322 				 u32 *peer_sid)
3323 {
3324 	struct selinux_policy *policy;
3325 	struct policydb *policydb;
3326 	struct sidtab *sidtab;
3327 	int rc;
3328 	struct context *nlbl_ctx;
3329 	struct context *xfrm_ctx;
3330 
3331 	*peer_sid = SECSID_NULL;
3332 
3333 	/* handle the common (which also happens to be the set of easy) cases
3334 	 * right away, these two if statements catch everything involving a
3335 	 * single or absent peer SID/label */
3336 	if (xfrm_sid == SECSID_NULL) {
3337 		*peer_sid = nlbl_sid;
3338 		return 0;
3339 	}
3340 	/* NOTE: an nlbl_type == NETLBL_NLTYPE_UNLABELED is a "fallback" label
3341 	 * and is treated as if nlbl_sid == SECSID_NULL when a XFRM SID/label
3342 	 * is present */
3343 	if (nlbl_sid == SECSID_NULL || nlbl_type == NETLBL_NLTYPE_UNLABELED) {
3344 		*peer_sid = xfrm_sid;
3345 		return 0;
3346 	}
3347 
3348 	if (!selinux_initialized(state))
3349 		return 0;
3350 
3351 	rcu_read_lock();
3352 	policy = rcu_dereference(state->policy);
3353 	policydb = &policy->policydb;
3354 	sidtab = policy->sidtab;
3355 
3356 	/*
3357 	 * We don't need to check initialized here since the only way both
3358 	 * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the
3359 	 * security server was initialized and state->initialized was true.
3360 	 */
3361 	if (!policydb->mls_enabled) {
3362 		rc = 0;
3363 		goto out;
3364 	}
3365 
3366 	rc = -EINVAL;
3367 	nlbl_ctx = sidtab_search(sidtab, nlbl_sid);
3368 	if (!nlbl_ctx) {
3369 		pr_err("SELinux: %s:  unrecognized SID %d\n",
3370 		       __func__, nlbl_sid);
3371 		goto out;
3372 	}
3373 	rc = -EINVAL;
3374 	xfrm_ctx = sidtab_search(sidtab, xfrm_sid);
3375 	if (!xfrm_ctx) {
3376 		pr_err("SELinux: %s:  unrecognized SID %d\n",
3377 		       __func__, xfrm_sid);
3378 		goto out;
3379 	}
3380 	rc = (mls_context_cmp(nlbl_ctx, xfrm_ctx) ? 0 : -EACCES);
3381 	if (rc)
3382 		goto out;
3383 
3384 	/* at present NetLabel SIDs/labels really only carry MLS
3385 	 * information so if the MLS portion of the NetLabel SID
3386 	 * matches the MLS portion of the labeled XFRM SID/label
3387 	 * then pass along the XFRM SID as it is the most
3388 	 * expressive */
3389 	*peer_sid = xfrm_sid;
3390 out:
3391 	rcu_read_unlock();
3392 	return rc;
3393 }
3394 
get_classes_callback(void * k,void * d,void * args)3395 static int get_classes_callback(void *k, void *d, void *args)
3396 {
3397 	struct class_datum *datum = d;
3398 	char *name = k, **classes = args;
3399 	int value = datum->value - 1;
3400 
3401 	classes[value] = kstrdup(name, GFP_ATOMIC);
3402 	if (!classes[value])
3403 		return -ENOMEM;
3404 
3405 	return 0;
3406 }
3407 
security_get_classes(struct selinux_policy * policy,char *** classes,int * nclasses)3408 int security_get_classes(struct selinux_policy *policy,
3409 			 char ***classes, int *nclasses)
3410 {
3411 	struct policydb *policydb;
3412 	int rc;
3413 
3414 	policydb = &policy->policydb;
3415 
3416 	rc = -ENOMEM;
3417 	*nclasses = policydb->p_classes.nprim;
3418 	*classes = kcalloc(*nclasses, sizeof(**classes), GFP_ATOMIC);
3419 	if (!*classes)
3420 		goto out;
3421 
3422 	rc = hashtab_map(&policydb->p_classes.table, get_classes_callback,
3423 			 *classes);
3424 	if (rc) {
3425 		int i;
3426 		for (i = 0; i < *nclasses; i++)
3427 			kfree((*classes)[i]);
3428 		kfree(*classes);
3429 	}
3430 
3431 out:
3432 	return rc;
3433 }
3434 
get_permissions_callback(void * k,void * d,void * args)3435 static int get_permissions_callback(void *k, void *d, void *args)
3436 {
3437 	struct perm_datum *datum = d;
3438 	char *name = k, **perms = args;
3439 	int value = datum->value - 1;
3440 
3441 	perms[value] = kstrdup(name, GFP_ATOMIC);
3442 	if (!perms[value])
3443 		return -ENOMEM;
3444 
3445 	return 0;
3446 }
3447 
security_get_permissions(struct selinux_policy * policy,char * class,char *** perms,int * nperms)3448 int security_get_permissions(struct selinux_policy *policy,
3449 			     char *class, char ***perms, int *nperms)
3450 {
3451 	struct policydb *policydb;
3452 	int rc, i;
3453 	struct class_datum *match;
3454 
3455 	policydb = &policy->policydb;
3456 
3457 	rc = -EINVAL;
3458 	match = symtab_search(&policydb->p_classes, class);
3459 	if (!match) {
3460 		pr_err("SELinux: %s:  unrecognized class %s\n",
3461 			__func__, class);
3462 		goto out;
3463 	}
3464 
3465 	rc = -ENOMEM;
3466 	*nperms = match->permissions.nprim;
3467 	*perms = kcalloc(*nperms, sizeof(**perms), GFP_ATOMIC);
3468 	if (!*perms)
3469 		goto out;
3470 
3471 	if (match->comdatum) {
3472 		rc = hashtab_map(&match->comdatum->permissions.table,
3473 				 get_permissions_callback, *perms);
3474 		if (rc)
3475 			goto err;
3476 	}
3477 
3478 	rc = hashtab_map(&match->permissions.table, get_permissions_callback,
3479 			 *perms);
3480 	if (rc)
3481 		goto err;
3482 
3483 out:
3484 	return rc;
3485 
3486 err:
3487 	for (i = 0; i < *nperms; i++)
3488 		kfree((*perms)[i]);
3489 	kfree(*perms);
3490 	return rc;
3491 }
3492 
security_get_reject_unknown(struct selinux_state * state)3493 int security_get_reject_unknown(struct selinux_state *state)
3494 {
3495 	struct selinux_policy *policy;
3496 	int value;
3497 
3498 	if (!selinux_initialized(state))
3499 		return 0;
3500 
3501 	rcu_read_lock();
3502 	policy = rcu_dereference(state->policy);
3503 	value = policy->policydb.reject_unknown;
3504 	rcu_read_unlock();
3505 	return value;
3506 }
3507 
security_get_allow_unknown(struct selinux_state * state)3508 int security_get_allow_unknown(struct selinux_state *state)
3509 {
3510 	struct selinux_policy *policy;
3511 	int value;
3512 
3513 	if (!selinux_initialized(state))
3514 		return 0;
3515 
3516 	rcu_read_lock();
3517 	policy = rcu_dereference(state->policy);
3518 	value = policy->policydb.allow_unknown;
3519 	rcu_read_unlock();
3520 	return value;
3521 }
3522 
3523 /**
3524  * security_policycap_supported - Check for a specific policy capability
3525  * @state: SELinux state
3526  * @req_cap: capability
3527  *
3528  * Description:
3529  * This function queries the currently loaded policy to see if it supports the
3530  * capability specified by @req_cap.  Returns true (1) if the capability is
3531  * supported, false (0) if it isn't supported.
3532  *
3533  */
security_policycap_supported(struct selinux_state * state,unsigned int req_cap)3534 int security_policycap_supported(struct selinux_state *state,
3535 				 unsigned int req_cap)
3536 {
3537 	struct selinux_policy *policy;
3538 	int rc;
3539 
3540 	if (!selinux_initialized(state))
3541 		return 0;
3542 
3543 	rcu_read_lock();
3544 	policy = rcu_dereference(state->policy);
3545 	rc = ebitmap_get_bit(&policy->policydb.policycaps, req_cap);
3546 	rcu_read_unlock();
3547 
3548 	return rc;
3549 }
3550 
3551 struct selinux_audit_rule {
3552 	u32 au_seqno;
3553 	struct context au_ctxt;
3554 };
3555 
selinux_audit_rule_free(void * vrule)3556 void selinux_audit_rule_free(void *vrule)
3557 {
3558 	struct selinux_audit_rule *rule = vrule;
3559 
3560 	if (rule) {
3561 		context_destroy(&rule->au_ctxt);
3562 		kfree(rule);
3563 	}
3564 }
3565 
selinux_audit_rule_init(u32 field,u32 op,char * rulestr,void ** vrule)3566 int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
3567 {
3568 	struct selinux_state *state = &selinux_state;
3569 	struct selinux_policy *policy;
3570 	struct policydb *policydb;
3571 	struct selinux_audit_rule *tmprule;
3572 	struct role_datum *roledatum;
3573 	struct type_datum *typedatum;
3574 	struct user_datum *userdatum;
3575 	struct selinux_audit_rule **rule = (struct selinux_audit_rule **)vrule;
3576 	int rc = 0;
3577 
3578 	*rule = NULL;
3579 
3580 	if (!selinux_initialized(state))
3581 		return -EOPNOTSUPP;
3582 
3583 	switch (field) {
3584 	case AUDIT_SUBJ_USER:
3585 	case AUDIT_SUBJ_ROLE:
3586 	case AUDIT_SUBJ_TYPE:
3587 	case AUDIT_OBJ_USER:
3588 	case AUDIT_OBJ_ROLE:
3589 	case AUDIT_OBJ_TYPE:
3590 		/* only 'equals' and 'not equals' fit user, role, and type */
3591 		if (op != Audit_equal && op != Audit_not_equal)
3592 			return -EINVAL;
3593 		break;
3594 	case AUDIT_SUBJ_SEN:
3595 	case AUDIT_SUBJ_CLR:
3596 	case AUDIT_OBJ_LEV_LOW:
3597 	case AUDIT_OBJ_LEV_HIGH:
3598 		/* we do not allow a range, indicated by the presence of '-' */
3599 		if (strchr(rulestr, '-'))
3600 			return -EINVAL;
3601 		break;
3602 	default:
3603 		/* only the above fields are valid */
3604 		return -EINVAL;
3605 	}
3606 
3607 	tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
3608 	if (!tmprule)
3609 		return -ENOMEM;
3610 
3611 	context_init(&tmprule->au_ctxt);
3612 
3613 	rcu_read_lock();
3614 	policy = rcu_dereference(state->policy);
3615 	policydb = &policy->policydb;
3616 
3617 	tmprule->au_seqno = policy->latest_granting;
3618 
3619 	switch (field) {
3620 	case AUDIT_SUBJ_USER:
3621 	case AUDIT_OBJ_USER:
3622 		rc = -EINVAL;
3623 		userdatum = symtab_search(&policydb->p_users, rulestr);
3624 		if (!userdatum)
3625 			goto out;
3626 		tmprule->au_ctxt.user = userdatum->value;
3627 		break;
3628 	case AUDIT_SUBJ_ROLE:
3629 	case AUDIT_OBJ_ROLE:
3630 		rc = -EINVAL;
3631 		roledatum = symtab_search(&policydb->p_roles, rulestr);
3632 		if (!roledatum)
3633 			goto out;
3634 		tmprule->au_ctxt.role = roledatum->value;
3635 		break;
3636 	case AUDIT_SUBJ_TYPE:
3637 	case AUDIT_OBJ_TYPE:
3638 		rc = -EINVAL;
3639 		typedatum = symtab_search(&policydb->p_types, rulestr);
3640 		if (!typedatum)
3641 			goto out;
3642 		tmprule->au_ctxt.type = typedatum->value;
3643 		break;
3644 	case AUDIT_SUBJ_SEN:
3645 	case AUDIT_SUBJ_CLR:
3646 	case AUDIT_OBJ_LEV_LOW:
3647 	case AUDIT_OBJ_LEV_HIGH:
3648 		rc = mls_from_string(policydb, rulestr, &tmprule->au_ctxt,
3649 				     GFP_ATOMIC);
3650 		if (rc)
3651 			goto out;
3652 		break;
3653 	}
3654 	rc = 0;
3655 out:
3656 	rcu_read_unlock();
3657 
3658 	if (rc) {
3659 		selinux_audit_rule_free(tmprule);
3660 		tmprule = NULL;
3661 	}
3662 
3663 	*rule = tmprule;
3664 
3665 	return rc;
3666 }
3667 
3668 /* Check to see if the rule contains any selinux fields */
selinux_audit_rule_known(struct audit_krule * rule)3669 int selinux_audit_rule_known(struct audit_krule *rule)
3670 {
3671 	int i;
3672 
3673 	for (i = 0; i < rule->field_count; i++) {
3674 		struct audit_field *f = &rule->fields[i];
3675 		switch (f->type) {
3676 		case AUDIT_SUBJ_USER:
3677 		case AUDIT_SUBJ_ROLE:
3678 		case AUDIT_SUBJ_TYPE:
3679 		case AUDIT_SUBJ_SEN:
3680 		case AUDIT_SUBJ_CLR:
3681 		case AUDIT_OBJ_USER:
3682 		case AUDIT_OBJ_ROLE:
3683 		case AUDIT_OBJ_TYPE:
3684 		case AUDIT_OBJ_LEV_LOW:
3685 		case AUDIT_OBJ_LEV_HIGH:
3686 			return 1;
3687 		}
3688 	}
3689 
3690 	return 0;
3691 }
3692 
selinux_audit_rule_match(u32 sid,u32 field,u32 op,void * vrule)3693 int selinux_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
3694 {
3695 	struct selinux_state *state = &selinux_state;
3696 	struct selinux_policy *policy;
3697 	struct context *ctxt;
3698 	struct mls_level *level;
3699 	struct selinux_audit_rule *rule = vrule;
3700 	int match = 0;
3701 
3702 	if (unlikely(!rule)) {
3703 		WARN_ONCE(1, "selinux_audit_rule_match: missing rule\n");
3704 		return -ENOENT;
3705 	}
3706 
3707 	if (!selinux_initialized(state))
3708 		return 0;
3709 
3710 	rcu_read_lock();
3711 
3712 	policy = rcu_dereference(state->policy);
3713 
3714 	if (rule->au_seqno < policy->latest_granting) {
3715 		match = -ESTALE;
3716 		goto out;
3717 	}
3718 
3719 	ctxt = sidtab_search(policy->sidtab, sid);
3720 	if (unlikely(!ctxt)) {
3721 		WARN_ONCE(1, "selinux_audit_rule_match: unrecognized SID %d\n",
3722 			  sid);
3723 		match = -ENOENT;
3724 		goto out;
3725 	}
3726 
3727 	/* a field/op pair that is not caught here will simply fall through
3728 	   without a match */
3729 	switch (field) {
3730 	case AUDIT_SUBJ_USER:
3731 	case AUDIT_OBJ_USER:
3732 		switch (op) {
3733 		case Audit_equal:
3734 			match = (ctxt->user == rule->au_ctxt.user);
3735 			break;
3736 		case Audit_not_equal:
3737 			match = (ctxt->user != rule->au_ctxt.user);
3738 			break;
3739 		}
3740 		break;
3741 	case AUDIT_SUBJ_ROLE:
3742 	case AUDIT_OBJ_ROLE:
3743 		switch (op) {
3744 		case Audit_equal:
3745 			match = (ctxt->role == rule->au_ctxt.role);
3746 			break;
3747 		case Audit_not_equal:
3748 			match = (ctxt->role != rule->au_ctxt.role);
3749 			break;
3750 		}
3751 		break;
3752 	case AUDIT_SUBJ_TYPE:
3753 	case AUDIT_OBJ_TYPE:
3754 		switch (op) {
3755 		case Audit_equal:
3756 			match = (ctxt->type == rule->au_ctxt.type);
3757 			break;
3758 		case Audit_not_equal:
3759 			match = (ctxt->type != rule->au_ctxt.type);
3760 			break;
3761 		}
3762 		break;
3763 	case AUDIT_SUBJ_SEN:
3764 	case AUDIT_SUBJ_CLR:
3765 	case AUDIT_OBJ_LEV_LOW:
3766 	case AUDIT_OBJ_LEV_HIGH:
3767 		level = ((field == AUDIT_SUBJ_SEN ||
3768 			  field == AUDIT_OBJ_LEV_LOW) ?
3769 			 &ctxt->range.level[0] : &ctxt->range.level[1]);
3770 		switch (op) {
3771 		case Audit_equal:
3772 			match = mls_level_eq(&rule->au_ctxt.range.level[0],
3773 					     level);
3774 			break;
3775 		case Audit_not_equal:
3776 			match = !mls_level_eq(&rule->au_ctxt.range.level[0],
3777 					      level);
3778 			break;
3779 		case Audit_lt:
3780 			match = (mls_level_dom(&rule->au_ctxt.range.level[0],
3781 					       level) &&
3782 				 !mls_level_eq(&rule->au_ctxt.range.level[0],
3783 					       level));
3784 			break;
3785 		case Audit_le:
3786 			match = mls_level_dom(&rule->au_ctxt.range.level[0],
3787 					      level);
3788 			break;
3789 		case Audit_gt:
3790 			match = (mls_level_dom(level,
3791 					      &rule->au_ctxt.range.level[0]) &&
3792 				 !mls_level_eq(level,
3793 					       &rule->au_ctxt.range.level[0]));
3794 			break;
3795 		case Audit_ge:
3796 			match = mls_level_dom(level,
3797 					      &rule->au_ctxt.range.level[0]);
3798 			break;
3799 		}
3800 	}
3801 
3802 out:
3803 	rcu_read_unlock();
3804 	return match;
3805 }
3806 
aurule_avc_callback(u32 event)3807 static int aurule_avc_callback(u32 event)
3808 {
3809 	if (event == AVC_CALLBACK_RESET)
3810 		return audit_update_lsm_rules();
3811 	return 0;
3812 }
3813 
aurule_init(void)3814 static int __init aurule_init(void)
3815 {
3816 	int err;
3817 
3818 	err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET);
3819 	if (err)
3820 		panic("avc_add_callback() failed, error %d\n", err);
3821 
3822 	return err;
3823 }
3824 __initcall(aurule_init);
3825 
3826 #ifdef CONFIG_NETLABEL
3827 /**
3828  * security_netlbl_cache_add - Add an entry to the NetLabel cache
3829  * @secattr: the NetLabel packet security attributes
3830  * @sid: the SELinux SID
3831  *
3832  * Description:
3833  * Attempt to cache the context in @ctx, which was derived from the packet in
3834  * @skb, in the NetLabel subsystem cache.  This function assumes @secattr has
3835  * already been initialized.
3836  *
3837  */
security_netlbl_cache_add(struct netlbl_lsm_secattr * secattr,u32 sid)3838 static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
3839 				      u32 sid)
3840 {
3841 	u32 *sid_cache;
3842 
3843 	sid_cache = kmalloc(sizeof(*sid_cache), GFP_ATOMIC);
3844 	if (sid_cache == NULL)
3845 		return;
3846 	secattr->cache = netlbl_secattr_cache_alloc(GFP_ATOMIC);
3847 	if (secattr->cache == NULL) {
3848 		kfree(sid_cache);
3849 		return;
3850 	}
3851 
3852 	*sid_cache = sid;
3853 	secattr->cache->free = kfree;
3854 	secattr->cache->data = sid_cache;
3855 	secattr->flags |= NETLBL_SECATTR_CACHE;
3856 }
3857 
3858 /**
3859  * security_netlbl_secattr_to_sid - Convert a NetLabel secattr to a SELinux SID
3860  * @state: SELinux state
3861  * @secattr: the NetLabel packet security attributes
3862  * @sid: the SELinux SID
3863  *
3864  * Description:
3865  * Convert the given NetLabel security attributes in @secattr into a
3866  * SELinux SID.  If the @secattr field does not contain a full SELinux
3867  * SID/context then use SECINITSID_NETMSG as the foundation.  If possible the
3868  * 'cache' field of @secattr is set and the CACHE flag is set; this is to
3869  * allow the @secattr to be used by NetLabel to cache the secattr to SID
3870  * conversion for future lookups.  Returns zero on success, negative values on
3871  * failure.
3872  *
3873  */
security_netlbl_secattr_to_sid(struct selinux_state * state,struct netlbl_lsm_secattr * secattr,u32 * sid)3874 int security_netlbl_secattr_to_sid(struct selinux_state *state,
3875 				   struct netlbl_lsm_secattr *secattr,
3876 				   u32 *sid)
3877 {
3878 	struct selinux_policy *policy;
3879 	struct policydb *policydb;
3880 	struct sidtab *sidtab;
3881 	int rc;
3882 	struct context *ctx;
3883 	struct context ctx_new;
3884 
3885 	if (!selinux_initialized(state)) {
3886 		*sid = SECSID_NULL;
3887 		return 0;
3888 	}
3889 
3890 retry:
3891 	rc = 0;
3892 	rcu_read_lock();
3893 	policy = rcu_dereference(state->policy);
3894 	policydb = &policy->policydb;
3895 	sidtab = policy->sidtab;
3896 
3897 	if (secattr->flags & NETLBL_SECATTR_CACHE)
3898 		*sid = *(u32 *)secattr->cache->data;
3899 	else if (secattr->flags & NETLBL_SECATTR_SECID)
3900 		*sid = secattr->attr.secid;
3901 	else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
3902 		rc = -EIDRM;
3903 		ctx = sidtab_search(sidtab, SECINITSID_NETMSG);
3904 		if (ctx == NULL)
3905 			goto out;
3906 
3907 		context_init(&ctx_new);
3908 		ctx_new.user = ctx->user;
3909 		ctx_new.role = ctx->role;
3910 		ctx_new.type = ctx->type;
3911 		mls_import_netlbl_lvl(policydb, &ctx_new, secattr);
3912 		if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
3913 			rc = mls_import_netlbl_cat(policydb, &ctx_new, secattr);
3914 			if (rc)
3915 				goto out;
3916 		}
3917 		rc = -EIDRM;
3918 		if (!mls_context_isvalid(policydb, &ctx_new)) {
3919 			ebitmap_destroy(&ctx_new.range.level[0].cat);
3920 			goto out;
3921 		}
3922 
3923 		rc = sidtab_context_to_sid(sidtab, &ctx_new, sid);
3924 		ebitmap_destroy(&ctx_new.range.level[0].cat);
3925 		if (rc == -ESTALE) {
3926 			rcu_read_unlock();
3927 			goto retry;
3928 		}
3929 		if (rc)
3930 			goto out;
3931 
3932 		security_netlbl_cache_add(secattr, *sid);
3933 	} else
3934 		*sid = SECSID_NULL;
3935 
3936 out:
3937 	rcu_read_unlock();
3938 	return rc;
3939 }
3940 
3941 /**
3942  * security_netlbl_sid_to_secattr - Convert a SELinux SID to a NetLabel secattr
3943  * @state: SELinux state
3944  * @sid: the SELinux SID
3945  * @secattr: the NetLabel packet security attributes
3946  *
3947  * Description:
3948  * Convert the given SELinux SID in @sid into a NetLabel security attribute.
3949  * Returns zero on success, negative values on failure.
3950  *
3951  */
security_netlbl_sid_to_secattr(struct selinux_state * state,u32 sid,struct netlbl_lsm_secattr * secattr)3952 int security_netlbl_sid_to_secattr(struct selinux_state *state,
3953 				   u32 sid, struct netlbl_lsm_secattr *secattr)
3954 {
3955 	struct selinux_policy *policy;
3956 	struct policydb *policydb;
3957 	int rc;
3958 	struct context *ctx;
3959 
3960 	if (!selinux_initialized(state))
3961 		return 0;
3962 
3963 	rcu_read_lock();
3964 	policy = rcu_dereference(state->policy);
3965 	policydb = &policy->policydb;
3966 
3967 	rc = -ENOENT;
3968 	ctx = sidtab_search(policy->sidtab, sid);
3969 	if (ctx == NULL)
3970 		goto out;
3971 
3972 	rc = -ENOMEM;
3973 	secattr->domain = kstrdup(sym_name(policydb, SYM_TYPES, ctx->type - 1),
3974 				  GFP_ATOMIC);
3975 	if (secattr->domain == NULL)
3976 		goto out;
3977 
3978 	secattr->attr.secid = sid;
3979 	secattr->flags |= NETLBL_SECATTR_DOMAIN_CPY | NETLBL_SECATTR_SECID;
3980 	mls_export_netlbl_lvl(policydb, ctx, secattr);
3981 	rc = mls_export_netlbl_cat(policydb, ctx, secattr);
3982 out:
3983 	rcu_read_unlock();
3984 	return rc;
3985 }
3986 #endif /* CONFIG_NETLABEL */
3987 
3988 /**
3989  * __security_read_policy - read the policy.
3990  * @policy: SELinux policy
3991  * @data: binary policy data
3992  * @len: length of data in bytes
3993  *
3994  */
__security_read_policy(struct selinux_policy * policy,void * data,size_t * len)3995 static int __security_read_policy(struct selinux_policy *policy,
3996 				  void *data, size_t *len)
3997 {
3998 	int rc;
3999 	struct policy_file fp;
4000 
4001 	fp.data = data;
4002 	fp.len = *len;
4003 
4004 	rc = policydb_write(&policy->policydb, &fp);
4005 	if (rc)
4006 		return rc;
4007 
4008 	*len = (unsigned long)fp.data - (unsigned long)data;
4009 	return 0;
4010 }
4011 
4012 /**
4013  * security_read_policy - read the policy.
4014  * @state: selinux_state
4015  * @data: binary policy data
4016  * @len: length of data in bytes
4017  *
4018  */
security_read_policy(struct selinux_state * state,void ** data,size_t * len)4019 int security_read_policy(struct selinux_state *state,
4020 			 void **data, size_t *len)
4021 {
4022 	struct selinux_policy *policy;
4023 
4024 	policy = rcu_dereference_protected(
4025 			state->policy, lockdep_is_held(&state->policy_mutex));
4026 	if (!policy)
4027 		return -EINVAL;
4028 
4029 	*len = policy->policydb.len;
4030 	*data = vmalloc_user(*len);
4031 	if (!*data)
4032 		return -ENOMEM;
4033 
4034 	return __security_read_policy(policy, *data, len);
4035 }
4036 
4037 /**
4038  * security_read_state_kernel - read the policy.
4039  * @state: selinux_state
4040  * @data: binary policy data
4041  * @len: length of data in bytes
4042  *
4043  * Allocates kernel memory for reading SELinux policy.
4044  * This function is for internal use only and should not
4045  * be used for returning data to user space.
4046  *
4047  * This function must be called with policy_mutex held.
4048  */
security_read_state_kernel(struct selinux_state * state,void ** data,size_t * len)4049 int security_read_state_kernel(struct selinux_state *state,
4050 			       void **data, size_t *len)
4051 {
4052 	int err;
4053 	struct selinux_policy *policy;
4054 
4055 	policy = rcu_dereference_protected(
4056 			state->policy, lockdep_is_held(&state->policy_mutex));
4057 	if (!policy)
4058 		return -EINVAL;
4059 
4060 	*len = policy->policydb.len;
4061 	*data = vmalloc(*len);
4062 	if (!*data)
4063 		return -ENOMEM;
4064 
4065 	err = __security_read_policy(policy, *data, len);
4066 	if (err) {
4067 		vfree(*data);
4068 		*data = NULL;
4069 		*len = 0;
4070 	}
4071 	return err;
4072 }
4073