1 /*
2  * NetLabel Domain Hash Table
3  *
4  * This file manages the domain hash table that NetLabel uses to determine
5  * which network labeling protocol to use for a given domain.  The NetLabel
6  * system manages static and dynamic label mappings for network protocols such
7  * as CIPSO and RIPSO.
8  *
9  * Author: Paul Moore <paul@paul-moore.com>
10  *
11  */
12 
13 /*
14  * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
15  *
16  * This program is free software;  you can redistribute it and/or modify
17  * it under the terms of the GNU General Public License as published by
18  * the Free Software Foundation; either version 2 of the License, or
19  * (at your option) any later version.
20  *
21  * This program is distributed in the hope that it will be useful,
22  * but WITHOUT ANY WARRANTY;  without even the implied warranty of
23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
24  * the GNU General Public License for more details.
25  *
26  * You should have received a copy of the GNU General Public License
27  * along with this program;  if not, write to the Free Software
28  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
29  *
30  */
31 
32 #include <linux/types.h>
33 #include <linux/rculist.h>
34 #include <linux/skbuff.h>
35 #include <linux/spinlock.h>
36 #include <linux/string.h>
37 #include <linux/audit.h>
38 #include <linux/slab.h>
39 #include <net/netlabel.h>
40 #include <net/cipso_ipv4.h>
41 #include <asm/bug.h>
42 
43 #include "netlabel_mgmt.h"
44 #include "netlabel_addrlist.h"
45 #include "netlabel_domainhash.h"
46 #include "netlabel_user.h"
47 
48 struct netlbl_domhsh_tbl {
49 	struct list_head *tbl;
50 	u32 size;
51 };
52 
53 /* Domain hash table */
54 /* updates should be so rare that having one spinlock for the entire hash table
55  * should be okay */
56 static DEFINE_SPINLOCK(netlbl_domhsh_lock);
57 #define netlbl_domhsh_rcu_deref(p) \
58 	rcu_dereference_check(p, lockdep_is_held(&netlbl_domhsh_lock))
59 static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL;
60 static struct netlbl_dom_map *netlbl_domhsh_def = NULL;
61 
62 /*
63  * Domain Hash Table Helper Functions
64  */
65 
66 /**
67  * netlbl_domhsh_free_entry - Frees a domain hash table entry
68  * @entry: the entry's RCU field
69  *
70  * Description:
71  * This function is designed to be used as a callback to the call_rcu()
72  * function so that the memory allocated to a hash table entry can be released
73  * safely.
74  *
75  */
76 static void netlbl_domhsh_free_entry(struct rcu_head *entry)
77 {
78 	struct netlbl_dom_map *ptr;
79 	struct netlbl_af4list *iter4;
80 	struct netlbl_af4list *tmp4;
81 #if IS_ENABLED(CONFIG_IPV6)
82 	struct netlbl_af6list *iter6;
83 	struct netlbl_af6list *tmp6;
84 #endif /* IPv6 */
85 
86 	ptr = container_of(entry, struct netlbl_dom_map, rcu);
87 	if (ptr->def.type == NETLBL_NLTYPE_ADDRSELECT) {
88 		netlbl_af4list_foreach_safe(iter4, tmp4,
89 					    &ptr->def.addrsel->list4) {
90 			netlbl_af4list_remove_entry(iter4);
91 			kfree(netlbl_domhsh_addr4_entry(iter4));
92 		}
93 #if IS_ENABLED(CONFIG_IPV6)
94 		netlbl_af6list_foreach_safe(iter6, tmp6,
95 					    &ptr->def.addrsel->list6) {
96 			netlbl_af6list_remove_entry(iter6);
97 			kfree(netlbl_domhsh_addr6_entry(iter6));
98 		}
99 #endif /* IPv6 */
100 	}
101 	kfree(ptr->domain);
102 	kfree(ptr);
103 }
104 
105 /**
106  * netlbl_domhsh_hash - Hashing function for the domain hash table
107  * @domain: the domain name to hash
108  *
109  * Description:
110  * This is the hashing function for the domain hash table, it returns the
111  * correct bucket number for the domain.  The caller is responsible for
112  * ensuring that the hash table is protected with either a RCU read lock or the
113  * hash table lock.
114  *
115  */
116 static u32 netlbl_domhsh_hash(const char *key)
117 {
118 	u32 iter;
119 	u32 val;
120 	u32 len;
121 
122 	/* This is taken (with slight modification) from
123 	 * security/selinux/ss/symtab.c:symhash() */
124 
125 	for (iter = 0, val = 0, len = strlen(key); iter < len; iter++)
126 		val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter];
127 	return val & (netlbl_domhsh_rcu_deref(netlbl_domhsh)->size - 1);
128 }
129 
130 /**
131  * netlbl_domhsh_search - Search for a domain entry
132  * @domain: the domain
133  *
134  * Description:
135  * Searches the domain hash table and returns a pointer to the hash table
136  * entry if found, otherwise NULL is returned.  The caller is responsible for
137  * ensuring that the hash table is protected with either a RCU read lock or the
138  * hash table lock.
139  *
140  */
141 static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain)
142 {
143 	u32 bkt;
144 	struct list_head *bkt_list;
145 	struct netlbl_dom_map *iter;
146 
147 	if (domain != NULL) {
148 		bkt = netlbl_domhsh_hash(domain);
149 		bkt_list = &netlbl_domhsh_rcu_deref(netlbl_domhsh)->tbl[bkt];
150 		list_for_each_entry_rcu(iter, bkt_list, list)
151 			if (iter->valid && strcmp(iter->domain, domain) == 0)
152 				return iter;
153 	}
154 
155 	return NULL;
156 }
157 
158 /**
159  * netlbl_domhsh_search_def - Search for a domain entry
160  * @domain: the domain
161  * @def: return default if no match is found
162  *
163  * Description:
164  * Searches the domain hash table and returns a pointer to the hash table
165  * entry if an exact match is found, if an exact match is not present in the
166  * hash table then the default entry is returned if valid otherwise NULL is
167  * returned.  The caller is responsible ensuring that the hash table is
168  * protected with either a RCU read lock or the hash table lock.
169  *
170  */
171 static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain)
172 {
173 	struct netlbl_dom_map *entry;
174 
175 	entry = netlbl_domhsh_search(domain);
176 	if (entry == NULL) {
177 		entry = netlbl_domhsh_rcu_deref(netlbl_domhsh_def);
178 		if (entry != NULL && !entry->valid)
179 			entry = NULL;
180 	}
181 
182 	return entry;
183 }
184 
185 /**
186  * netlbl_domhsh_audit_add - Generate an audit entry for an add event
187  * @entry: the entry being added
188  * @addr4: the IPv4 address information
189  * @addr6: the IPv6 address information
190  * @result: the result code
191  * @audit_info: NetLabel audit information
192  *
193  * Description:
194  * Generate an audit record for adding a new NetLabel/LSM mapping entry with
195  * the given information.  Caller is responsible for holding the necessary
196  * locks.
197  *
198  */
199 static void netlbl_domhsh_audit_add(struct netlbl_dom_map *entry,
200 				    struct netlbl_af4list *addr4,
201 				    struct netlbl_af6list *addr6,
202 				    int result,
203 				    struct netlbl_audit *audit_info)
204 {
205 	struct audit_buffer *audit_buf;
206 	struct cipso_v4_doi *cipsov4 = NULL;
207 	u32 type;
208 
209 	audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info);
210 	if (audit_buf != NULL) {
211 		audit_log_format(audit_buf, " nlbl_domain=%s",
212 				 entry->domain ? entry->domain : "(default)");
213 		if (addr4 != NULL) {
214 			struct netlbl_domaddr4_map *map4;
215 			map4 = netlbl_domhsh_addr4_entry(addr4);
216 			type = map4->def.type;
217 			cipsov4 = map4->def.cipso;
218 			netlbl_af4list_audit_addr(audit_buf, 0, NULL,
219 						  addr4->addr, addr4->mask);
220 #if IS_ENABLED(CONFIG_IPV6)
221 		} else if (addr6 != NULL) {
222 			struct netlbl_domaddr6_map *map6;
223 			map6 = netlbl_domhsh_addr6_entry(addr6);
224 			type = map6->def.type;
225 			netlbl_af6list_audit_addr(audit_buf, 0, NULL,
226 						  &addr6->addr, &addr6->mask);
227 #endif /* IPv6 */
228 		} else {
229 			type = entry->def.type;
230 			cipsov4 = entry->def.cipso;
231 		}
232 		switch (type) {
233 		case NETLBL_NLTYPE_UNLABELED:
234 			audit_log_format(audit_buf, " nlbl_protocol=unlbl");
235 			break;
236 		case NETLBL_NLTYPE_CIPSOV4:
237 			BUG_ON(cipsov4 == NULL);
238 			audit_log_format(audit_buf,
239 					 " nlbl_protocol=cipsov4 cipso_doi=%u",
240 					 cipsov4->doi);
241 			break;
242 		}
243 		audit_log_format(audit_buf, " res=%u", result == 0 ? 1 : 0);
244 		audit_log_end(audit_buf);
245 	}
246 }
247 
248 /**
249  * netlbl_domhsh_validate - Validate a new domain mapping entry
250  * @entry: the entry to validate
251  *
252  * This function validates the new domain mapping entry to ensure that it is
253  * a valid entry.  Returns zero on success, negative values on failure.
254  *
255  */
256 static int netlbl_domhsh_validate(const struct netlbl_dom_map *entry)
257 {
258 	struct netlbl_af4list *iter4;
259 	struct netlbl_domaddr4_map *map4;
260 #if IS_ENABLED(CONFIG_IPV6)
261 	struct netlbl_af6list *iter6;
262 	struct netlbl_domaddr6_map *map6;
263 #endif /* IPv6 */
264 
265 	if (entry == NULL)
266 		return -EINVAL;
267 
268 	switch (entry->def.type) {
269 	case NETLBL_NLTYPE_UNLABELED:
270 		if (entry->def.cipso != NULL || entry->def.addrsel != NULL)
271 			return -EINVAL;
272 		break;
273 	case NETLBL_NLTYPE_CIPSOV4:
274 		if (entry->def.cipso == NULL)
275 			return -EINVAL;
276 		break;
277 	case NETLBL_NLTYPE_ADDRSELECT:
278 		netlbl_af4list_foreach(iter4, &entry->def.addrsel->list4) {
279 			map4 = netlbl_domhsh_addr4_entry(iter4);
280 			switch (map4->def.type) {
281 			case NETLBL_NLTYPE_UNLABELED:
282 				if (map4->def.cipso != NULL)
283 					return -EINVAL;
284 				break;
285 			case NETLBL_NLTYPE_CIPSOV4:
286 				if (map4->def.cipso == NULL)
287 					return -EINVAL;
288 				break;
289 			default:
290 				return -EINVAL;
291 			}
292 		}
293 #if IS_ENABLED(CONFIG_IPV6)
294 		netlbl_af6list_foreach(iter6, &entry->def.addrsel->list6) {
295 			map6 = netlbl_domhsh_addr6_entry(iter6);
296 			switch (map6->def.type) {
297 			case NETLBL_NLTYPE_UNLABELED:
298 				break;
299 			default:
300 				return -EINVAL;
301 			}
302 		}
303 #endif /* IPv6 */
304 		break;
305 	default:
306 		return -EINVAL;
307 	}
308 
309 	return 0;
310 }
311 
312 /*
313  * Domain Hash Table Functions
314  */
315 
316 /**
317  * netlbl_domhsh_init - Init for the domain hash
318  * @size: the number of bits to use for the hash buckets
319  *
320  * Description:
321  * Initializes the domain hash table, should be called only by
322  * netlbl_user_init() during initialization.  Returns zero on success, non-zero
323  * values on error.
324  *
325  */
326 int __init netlbl_domhsh_init(u32 size)
327 {
328 	u32 iter;
329 	struct netlbl_domhsh_tbl *hsh_tbl;
330 
331 	if (size == 0)
332 		return -EINVAL;
333 
334 	hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL);
335 	if (hsh_tbl == NULL)
336 		return -ENOMEM;
337 	hsh_tbl->size = 1 << size;
338 	hsh_tbl->tbl = kcalloc(hsh_tbl->size,
339 			       sizeof(struct list_head),
340 			       GFP_KERNEL);
341 	if (hsh_tbl->tbl == NULL) {
342 		kfree(hsh_tbl);
343 		return -ENOMEM;
344 	}
345 	for (iter = 0; iter < hsh_tbl->size; iter++)
346 		INIT_LIST_HEAD(&hsh_tbl->tbl[iter]);
347 
348 	spin_lock(&netlbl_domhsh_lock);
349 	rcu_assign_pointer(netlbl_domhsh, hsh_tbl);
350 	spin_unlock(&netlbl_domhsh_lock);
351 
352 	return 0;
353 }
354 
355 /**
356  * netlbl_domhsh_add - Adds a entry to the domain hash table
357  * @entry: the entry to add
358  * @audit_info: NetLabel audit information
359  *
360  * Description:
361  * Adds a new entry to the domain hash table and handles any updates to the
362  * lower level protocol handler (i.e. CIPSO).  Returns zero on success,
363  * negative on failure.
364  *
365  */
366 int netlbl_domhsh_add(struct netlbl_dom_map *entry,
367 		      struct netlbl_audit *audit_info)
368 {
369 	int ret_val = 0;
370 	struct netlbl_dom_map *entry_old;
371 	struct netlbl_af4list *iter4;
372 	struct netlbl_af4list *tmp4;
373 #if IS_ENABLED(CONFIG_IPV6)
374 	struct netlbl_af6list *iter6;
375 	struct netlbl_af6list *tmp6;
376 #endif /* IPv6 */
377 
378 	ret_val = netlbl_domhsh_validate(entry);
379 	if (ret_val != 0)
380 		return ret_val;
381 
382 	/* XXX - we can remove this RCU read lock as the spinlock protects the
383 	 *       entire function, but before we do we need to fixup the
384 	 *       netlbl_af[4,6]list RCU functions to do "the right thing" with
385 	 *       respect to rcu_dereference() when only a spinlock is held. */
386 	rcu_read_lock();
387 	spin_lock(&netlbl_domhsh_lock);
388 	if (entry->domain != NULL)
389 		entry_old = netlbl_domhsh_search(entry->domain);
390 	else
391 		entry_old = netlbl_domhsh_search_def(entry->domain);
392 	if (entry_old == NULL) {
393 		entry->valid = 1;
394 
395 		if (entry->domain != NULL) {
396 			u32 bkt = netlbl_domhsh_hash(entry->domain);
397 			list_add_tail_rcu(&entry->list,
398 				    &rcu_dereference(netlbl_domhsh)->tbl[bkt]);
399 		} else {
400 			INIT_LIST_HEAD(&entry->list);
401 			rcu_assign_pointer(netlbl_domhsh_def, entry);
402 		}
403 
404 		if (entry->def.type == NETLBL_NLTYPE_ADDRSELECT) {
405 			netlbl_af4list_foreach_rcu(iter4,
406 						   &entry->def.addrsel->list4)
407 				netlbl_domhsh_audit_add(entry, iter4, NULL,
408 							ret_val, audit_info);
409 #if IS_ENABLED(CONFIG_IPV6)
410 			netlbl_af6list_foreach_rcu(iter6,
411 						   &entry->def.addrsel->list6)
412 				netlbl_domhsh_audit_add(entry, NULL, iter6,
413 							ret_val, audit_info);
414 #endif /* IPv6 */
415 		} else
416 			netlbl_domhsh_audit_add(entry, NULL, NULL,
417 						ret_val, audit_info);
418 	} else if (entry_old->def.type == NETLBL_NLTYPE_ADDRSELECT &&
419 		   entry->def.type == NETLBL_NLTYPE_ADDRSELECT) {
420 		struct list_head *old_list4;
421 		struct list_head *old_list6;
422 
423 		old_list4 = &entry_old->def.addrsel->list4;
424 		old_list6 = &entry_old->def.addrsel->list6;
425 
426 		/* we only allow the addition of address selectors if all of
427 		 * the selectors do not exist in the existing domain map */
428 		netlbl_af4list_foreach_rcu(iter4, &entry->def.addrsel->list4)
429 			if (netlbl_af4list_search_exact(iter4->addr,
430 							iter4->mask,
431 							old_list4)) {
432 				ret_val = -EEXIST;
433 				goto add_return;
434 			}
435 #if IS_ENABLED(CONFIG_IPV6)
436 		netlbl_af6list_foreach_rcu(iter6, &entry->def.addrsel->list6)
437 			if (netlbl_af6list_search_exact(&iter6->addr,
438 							&iter6->mask,
439 							old_list6)) {
440 				ret_val = -EEXIST;
441 				goto add_return;
442 			}
443 #endif /* IPv6 */
444 
445 		netlbl_af4list_foreach_safe(iter4, tmp4,
446 					    &entry->def.addrsel->list4) {
447 			netlbl_af4list_remove_entry(iter4);
448 			iter4->valid = 1;
449 			ret_val = netlbl_af4list_add(iter4, old_list4);
450 			netlbl_domhsh_audit_add(entry_old, iter4, NULL,
451 						ret_val, audit_info);
452 			if (ret_val != 0)
453 				goto add_return;
454 		}
455 #if IS_ENABLED(CONFIG_IPV6)
456 		netlbl_af6list_foreach_safe(iter6, tmp6,
457 					    &entry->def.addrsel->list6) {
458 			netlbl_af6list_remove_entry(iter6);
459 			iter6->valid = 1;
460 			ret_val = netlbl_af6list_add(iter6, old_list6);
461 			netlbl_domhsh_audit_add(entry_old, NULL, iter6,
462 						ret_val, audit_info);
463 			if (ret_val != 0)
464 				goto add_return;
465 		}
466 #endif /* IPv6 */
467 	} else
468 		ret_val = -EINVAL;
469 
470 add_return:
471 	spin_unlock(&netlbl_domhsh_lock);
472 	rcu_read_unlock();
473 	return ret_val;
474 }
475 
476 /**
477  * netlbl_domhsh_add_default - Adds the default entry to the domain hash table
478  * @entry: the entry to add
479  * @audit_info: NetLabel audit information
480  *
481  * Description:
482  * Adds a new default entry to the domain hash table and handles any updates
483  * to the lower level protocol handler (i.e. CIPSO).  Returns zero on success,
484  * negative on failure.
485  *
486  */
487 int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
488 			      struct netlbl_audit *audit_info)
489 {
490 	return netlbl_domhsh_add(entry, audit_info);
491 }
492 
493 /**
494  * netlbl_domhsh_remove_entry - Removes a given entry from the domain table
495  * @entry: the entry to remove
496  * @audit_info: NetLabel audit information
497  *
498  * Description:
499  * Removes an entry from the domain hash table and handles any updates to the
500  * lower level protocol handler (i.e. CIPSO).  Caller is responsible for
501  * ensuring that the RCU read lock is held.  Returns zero on success, negative
502  * on failure.
503  *
504  */
505 int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry,
506 			       struct netlbl_audit *audit_info)
507 {
508 	int ret_val = 0;
509 	struct audit_buffer *audit_buf;
510 
511 	if (entry == NULL)
512 		return -ENOENT;
513 
514 	spin_lock(&netlbl_domhsh_lock);
515 	if (entry->valid) {
516 		entry->valid = 0;
517 		if (entry != rcu_dereference(netlbl_domhsh_def))
518 			list_del_rcu(&entry->list);
519 		else
520 			RCU_INIT_POINTER(netlbl_domhsh_def, NULL);
521 	} else
522 		ret_val = -ENOENT;
523 	spin_unlock(&netlbl_domhsh_lock);
524 
525 	audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info);
526 	if (audit_buf != NULL) {
527 		audit_log_format(audit_buf,
528 				 " nlbl_domain=%s res=%u",
529 				 entry->domain ? entry->domain : "(default)",
530 				 ret_val == 0 ? 1 : 0);
531 		audit_log_end(audit_buf);
532 	}
533 
534 	if (ret_val == 0) {
535 		struct netlbl_af4list *iter4;
536 		struct netlbl_domaddr4_map *map4;
537 
538 		switch (entry->def.type) {
539 		case NETLBL_NLTYPE_ADDRSELECT:
540 			netlbl_af4list_foreach_rcu(iter4,
541 					     &entry->def.addrsel->list4) {
542 				map4 = netlbl_domhsh_addr4_entry(iter4);
543 				cipso_v4_doi_putdef(map4->def.cipso);
544 			}
545 			/* no need to check the IPv6 list since we currently
546 			 * support only unlabeled protocols for IPv6 */
547 			break;
548 		case NETLBL_NLTYPE_CIPSOV4:
549 			cipso_v4_doi_putdef(entry->def.cipso);
550 			break;
551 		}
552 		call_rcu(&entry->rcu, netlbl_domhsh_free_entry);
553 	}
554 
555 	return ret_val;
556 }
557 
558 /**
559  * netlbl_domhsh_remove_af4 - Removes an address selector entry
560  * @domain: the domain
561  * @addr: IPv4 address
562  * @mask: IPv4 address mask
563  * @audit_info: NetLabel audit information
564  *
565  * Description:
566  * Removes an individual address selector from a domain mapping and potentially
567  * the entire mapping if it is empty.  Returns zero on success, negative values
568  * on failure.
569  *
570  */
571 int netlbl_domhsh_remove_af4(const char *domain,
572 			     const struct in_addr *addr,
573 			     const struct in_addr *mask,
574 			     struct netlbl_audit *audit_info)
575 {
576 	struct netlbl_dom_map *entry_map;
577 	struct netlbl_af4list *entry_addr;
578 	struct netlbl_af4list *iter4;
579 #if IS_ENABLED(CONFIG_IPV6)
580 	struct netlbl_af6list *iter6;
581 #endif /* IPv6 */
582 	struct netlbl_domaddr4_map *entry;
583 
584 	rcu_read_lock();
585 
586 	if (domain)
587 		entry_map = netlbl_domhsh_search(domain);
588 	else
589 		entry_map = netlbl_domhsh_search_def(domain);
590 	if (entry_map == NULL ||
591 	    entry_map->def.type != NETLBL_NLTYPE_ADDRSELECT)
592 		goto remove_af4_failure;
593 
594 	spin_lock(&netlbl_domhsh_lock);
595 	entry_addr = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
596 					   &entry_map->def.addrsel->list4);
597 	spin_unlock(&netlbl_domhsh_lock);
598 
599 	if (entry_addr == NULL)
600 		goto remove_af4_failure;
601 	netlbl_af4list_foreach_rcu(iter4, &entry_map->def.addrsel->list4)
602 		goto remove_af4_single_addr;
603 #if IS_ENABLED(CONFIG_IPV6)
604 	netlbl_af6list_foreach_rcu(iter6, &entry_map->def.addrsel->list6)
605 		goto remove_af4_single_addr;
606 #endif /* IPv6 */
607 	/* the domain mapping is empty so remove it from the mapping table */
608 	netlbl_domhsh_remove_entry(entry_map, audit_info);
609 
610 remove_af4_single_addr:
611 	rcu_read_unlock();
612 	/* yick, we can't use call_rcu here because we don't have a rcu head
613 	 * pointer but hopefully this should be a rare case so the pause
614 	 * shouldn't be a problem */
615 	synchronize_rcu();
616 	entry = netlbl_domhsh_addr4_entry(entry_addr);
617 	cipso_v4_doi_putdef(entry->def.cipso);
618 	kfree(entry);
619 	return 0;
620 
621 remove_af4_failure:
622 	rcu_read_unlock();
623 	return -ENOENT;
624 }
625 
626 /**
627  * netlbl_domhsh_remove - Removes an entry from the domain hash table
628  * @domain: the domain to remove
629  * @audit_info: NetLabel audit information
630  *
631  * Description:
632  * Removes an entry from the domain hash table and handles any updates to the
633  * lower level protocol handler (i.e. CIPSO).  Returns zero on success,
634  * negative on failure.
635  *
636  */
637 int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info)
638 {
639 	int ret_val;
640 	struct netlbl_dom_map *entry;
641 
642 	rcu_read_lock();
643 	if (domain)
644 		entry = netlbl_domhsh_search(domain);
645 	else
646 		entry = netlbl_domhsh_search_def(domain);
647 	ret_val = netlbl_domhsh_remove_entry(entry, audit_info);
648 	rcu_read_unlock();
649 
650 	return ret_val;
651 }
652 
653 /**
654  * netlbl_domhsh_remove_default - Removes the default entry from the table
655  * @audit_info: NetLabel audit information
656  *
657  * Description:
658  * Removes/resets the default entry for the domain hash table and handles any
659  * updates to the lower level protocol handler (i.e. CIPSO).  Returns zero on
660  * success, non-zero on failure.
661  *
662  */
663 int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info)
664 {
665 	return netlbl_domhsh_remove(NULL, audit_info);
666 }
667 
668 /**
669  * netlbl_domhsh_getentry - Get an entry from the domain hash table
670  * @domain: the domain name to search for
671  *
672  * Description:
673  * Look through the domain hash table searching for an entry to match @domain,
674  * return a pointer to a copy of the entry or NULL.  The caller is responsible
675  * for ensuring that rcu_read_[un]lock() is called.
676  *
677  */
678 struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain)
679 {
680 	return netlbl_domhsh_search_def(domain);
681 }
682 
683 /**
684  * netlbl_domhsh_getentry_af4 - Get an entry from the domain hash table
685  * @domain: the domain name to search for
686  * @addr: the IP address to search for
687  *
688  * Description:
689  * Look through the domain hash table searching for an entry to match @domain
690  * and @addr, return a pointer to a copy of the entry or NULL.  The caller is
691  * responsible for ensuring that rcu_read_[un]lock() is called.
692  *
693  */
694 struct netlbl_dommap_def *netlbl_domhsh_getentry_af4(const char *domain,
695 						     __be32 addr)
696 {
697 	struct netlbl_dom_map *dom_iter;
698 	struct netlbl_af4list *addr_iter;
699 
700 	dom_iter = netlbl_domhsh_search_def(domain);
701 	if (dom_iter == NULL)
702 		return NULL;
703 
704 	if (dom_iter->def.type != NETLBL_NLTYPE_ADDRSELECT)
705 		return &dom_iter->def;
706 	addr_iter = netlbl_af4list_search(addr, &dom_iter->def.addrsel->list4);
707 	if (addr_iter == NULL)
708 		return NULL;
709 	return &(netlbl_domhsh_addr4_entry(addr_iter)->def);
710 }
711 
712 #if IS_ENABLED(CONFIG_IPV6)
713 /**
714  * netlbl_domhsh_getentry_af6 - Get an entry from the domain hash table
715  * @domain: the domain name to search for
716  * @addr: the IP address to search for
717  *
718  * Description:
719  * Look through the domain hash table searching for an entry to match @domain
720  * and @addr, return a pointer to a copy of the entry or NULL.  The caller is
721  * responsible for ensuring that rcu_read_[un]lock() is called.
722  *
723  */
724 struct netlbl_dommap_def *netlbl_domhsh_getentry_af6(const char *domain,
725 						   const struct in6_addr *addr)
726 {
727 	struct netlbl_dom_map *dom_iter;
728 	struct netlbl_af6list *addr_iter;
729 
730 	dom_iter = netlbl_domhsh_search_def(domain);
731 	if (dom_iter == NULL)
732 		return NULL;
733 
734 	if (dom_iter->def.type != NETLBL_NLTYPE_ADDRSELECT)
735 		return &dom_iter->def;
736 	addr_iter = netlbl_af6list_search(addr, &dom_iter->def.addrsel->list6);
737 	if (addr_iter == NULL)
738 		return NULL;
739 	return &(netlbl_domhsh_addr6_entry(addr_iter)->def);
740 }
741 #endif /* IPv6 */
742 
743 /**
744  * netlbl_domhsh_walk - Iterate through the domain mapping hash table
745  * @skip_bkt: the number of buckets to skip at the start
746  * @skip_chain: the number of entries to skip in the first iterated bucket
747  * @callback: callback for each entry
748  * @cb_arg: argument for the callback function
749  *
750  * Description:
751  * Interate over the domain mapping hash table, skipping the first @skip_bkt
752  * buckets and @skip_chain entries.  For each entry in the table call
753  * @callback, if @callback returns a negative value stop 'walking' through the
754  * table and return.  Updates the values in @skip_bkt and @skip_chain on
755  * return.  Returns zero on success, negative values on failure.
756  *
757  */
758 int netlbl_domhsh_walk(u32 *skip_bkt,
759 		     u32 *skip_chain,
760 		     int (*callback) (struct netlbl_dom_map *entry, void *arg),
761 		     void *cb_arg)
762 {
763 	int ret_val = -ENOENT;
764 	u32 iter_bkt;
765 	struct list_head *iter_list;
766 	struct netlbl_dom_map *iter_entry;
767 	u32 chain_cnt = 0;
768 
769 	rcu_read_lock();
770 	for (iter_bkt = *skip_bkt;
771 	     iter_bkt < rcu_dereference(netlbl_domhsh)->size;
772 	     iter_bkt++, chain_cnt = 0) {
773 		iter_list = &rcu_dereference(netlbl_domhsh)->tbl[iter_bkt];
774 		list_for_each_entry_rcu(iter_entry, iter_list, list)
775 			if (iter_entry->valid) {
776 				if (chain_cnt++ < *skip_chain)
777 					continue;
778 				ret_val = callback(iter_entry, cb_arg);
779 				if (ret_val < 0) {
780 					chain_cnt--;
781 					goto walk_return;
782 				}
783 			}
784 	}
785 
786 walk_return:
787 	rcu_read_unlock();
788 	*skip_bkt = iter_bkt;
789 	*skip_chain = chain_cnt;
790 	return ret_val;
791 }
792