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1 /*
2  * CIPSO - Commercial IP Security Option
3  *
4  * This is an implementation of the CIPSO 2.2 protocol as specified in
5  * draft-ietf-cipso-ipsecurity-01.txt with additional tag types as found in
6  * FIPS-188.  While CIPSO never became a full IETF RFC standard many vendors
7  * have chosen to adopt the protocol and over the years it has become a
8  * de-facto standard for labeled networking.
9  *
10  * The CIPSO draft specification can be found in the kernel's Documentation
11  * directory as well as the following URL:
12  *   http://netlabel.sourceforge.net/files/draft-ietf-cipso-ipsecurity-01.txt
13  * The FIPS-188 specification can be found at the following URL:
14  *   http://www.itl.nist.gov/fipspubs/fip188.htm
15  *
16  * Author: Paul Moore <paul.moore@hp.com>
17  *
18  */
19 
20 /*
21  * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
22  *
23  * This program is free software;  you can redistribute it and/or modify
24  * it under the terms of the GNU General Public License as published by
25  * the Free Software Foundation; either version 2 of the License, or
26  * (at your option) any later version.
27  *
28  * This program is distributed in the hope that it will be useful,
29  * but WITHOUT ANY WARRANTY;  without even the implied warranty of
30  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
31  * the GNU General Public License for more details.
32  *
33  * You should have received a copy of the GNU General Public License
34  * along with this program;  if not, write to the Free Software
35  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
36  *
37  */
38 
39 #include <linux/init.h>
40 #include <linux/types.h>
41 #include <linux/rcupdate.h>
42 #include <linux/list.h>
43 #include <linux/spinlock.h>
44 #include <linux/string.h>
45 #include <linux/jhash.h>
46 #include <linux/audit.h>
47 #include <net/ip.h>
48 #include <net/icmp.h>
49 #include <net/tcp.h>
50 #include <net/netlabel.h>
51 #include <net/cipso_ipv4.h>
52 #include <asm/atomic.h>
53 #include <asm/bug.h>
54 #include <asm/unaligned.h>
55 
56 /* List of available DOI definitions */
57 /* XXX - This currently assumes a minimal number of different DOIs in use,
58  * if in practice there are a lot of different DOIs this list should
59  * probably be turned into a hash table or something similar so we
60  * can do quick lookups. */
61 static DEFINE_SPINLOCK(cipso_v4_doi_list_lock);
62 static LIST_HEAD(cipso_v4_doi_list);
63 
64 /* Label mapping cache */
65 int cipso_v4_cache_enabled = 1;
66 int cipso_v4_cache_bucketsize = 10;
67 #define CIPSO_V4_CACHE_BUCKETBITS     7
68 #define CIPSO_V4_CACHE_BUCKETS        (1 << CIPSO_V4_CACHE_BUCKETBITS)
69 #define CIPSO_V4_CACHE_REORDERLIMIT   10
70 struct cipso_v4_map_cache_bkt {
71 	spinlock_t lock;
72 	u32 size;
73 	struct list_head list;
74 };
75 struct cipso_v4_map_cache_entry {
76 	u32 hash;
77 	unsigned char *key;
78 	size_t key_len;
79 
80 	struct netlbl_lsm_cache *lsm_data;
81 
82 	u32 activity;
83 	struct list_head list;
84 };
85 static struct cipso_v4_map_cache_bkt *cipso_v4_cache = NULL;
86 
87 /* Restricted bitmap (tag #1) flags */
88 int cipso_v4_rbm_optfmt = 0;
89 int cipso_v4_rbm_strictvalid = 1;
90 
91 /*
92  * Protocol Constants
93  */
94 
95 /* Maximum size of the CIPSO IP option, derived from the fact that the maximum
96  * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */
97 #define CIPSO_V4_OPT_LEN_MAX          40
98 
99 /* Length of the base CIPSO option, this includes the option type (1 byte), the
100  * option length (1 byte), and the DOI (4 bytes). */
101 #define CIPSO_V4_HDR_LEN              6
102 
103 /* Base length of the restrictive category bitmap tag (tag #1). */
104 #define CIPSO_V4_TAG_RBM_BLEN         4
105 
106 /* Base length of the enumerated category tag (tag #2). */
107 #define CIPSO_V4_TAG_ENUM_BLEN        4
108 
109 /* Base length of the ranged categories bitmap tag (tag #5). */
110 #define CIPSO_V4_TAG_RNG_BLEN         4
111 /* The maximum number of category ranges permitted in the ranged category tag
112  * (tag #5).  You may note that the IETF draft states that the maximum number
113  * of category ranges is 7, but if the low end of the last category range is
114  * zero then it is possibile to fit 8 category ranges because the zero should
115  * be omitted. */
116 #define CIPSO_V4_TAG_RNG_CAT_MAX      8
117 
118 /* Base length of the local tag (non-standard tag).
119  *  Tag definition (may change between kernel versions)
120  *
121  * 0          8          16         24         32
122  * +----------+----------+----------+----------+
123  * | 10000000 | 00000110 | 32-bit secid value  |
124  * +----------+----------+----------+----------+
125  * | in (host byte order)|
126  * +----------+----------+
127  *
128  */
129 #define CIPSO_V4_TAG_LOC_BLEN         6
130 
131 /*
132  * Helper Functions
133  */
134 
135 /**
136  * cipso_v4_bitmap_walk - Walk a bitmap looking for a bit
137  * @bitmap: the bitmap
138  * @bitmap_len: length in bits
139  * @offset: starting offset
140  * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit
141  *
142  * Description:
143  * Starting at @offset, walk the bitmap from left to right until either the
144  * desired bit is found or we reach the end.  Return the bit offset, -1 if
145  * not found, or -2 if error.
146  */
cipso_v4_bitmap_walk(const unsigned char * bitmap,u32 bitmap_len,u32 offset,u8 state)147 static int cipso_v4_bitmap_walk(const unsigned char *bitmap,
148 				u32 bitmap_len,
149 				u32 offset,
150 				u8 state)
151 {
152 	u32 bit_spot;
153 	u32 byte_offset;
154 	unsigned char bitmask;
155 	unsigned char byte;
156 
157 	/* gcc always rounds to zero when doing integer division */
158 	byte_offset = offset / 8;
159 	byte = bitmap[byte_offset];
160 	bit_spot = offset;
161 	bitmask = 0x80 >> (offset % 8);
162 
163 	while (bit_spot < bitmap_len) {
164 		if ((state && (byte & bitmask) == bitmask) ||
165 		    (state == 0 && (byte & bitmask) == 0))
166 			return bit_spot;
167 
168 		bit_spot++;
169 		bitmask >>= 1;
170 		if (bitmask == 0) {
171 			byte = bitmap[++byte_offset];
172 			bitmask = 0x80;
173 		}
174 	}
175 
176 	return -1;
177 }
178 
179 /**
180  * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap
181  * @bitmap: the bitmap
182  * @bit: the bit
183  * @state: if non-zero, set the bit (1) else clear the bit (0)
184  *
185  * Description:
186  * Set a single bit in the bitmask.  Returns zero on success, negative values
187  * on error.
188  */
cipso_v4_bitmap_setbit(unsigned char * bitmap,u32 bit,u8 state)189 static void cipso_v4_bitmap_setbit(unsigned char *bitmap,
190 				   u32 bit,
191 				   u8 state)
192 {
193 	u32 byte_spot;
194 	u8 bitmask;
195 
196 	/* gcc always rounds to zero when doing integer division */
197 	byte_spot = bit / 8;
198 	bitmask = 0x80 >> (bit % 8);
199 	if (state)
200 		bitmap[byte_spot] |= bitmask;
201 	else
202 		bitmap[byte_spot] &= ~bitmask;
203 }
204 
205 /**
206  * cipso_v4_cache_entry_free - Frees a cache entry
207  * @entry: the entry to free
208  *
209  * Description:
210  * This function frees the memory associated with a cache entry including the
211  * LSM cache data if there are no longer any users, i.e. reference count == 0.
212  *
213  */
cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry * entry)214 static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry)
215 {
216 	if (entry->lsm_data)
217 		netlbl_secattr_cache_free(entry->lsm_data);
218 	kfree(entry->key);
219 	kfree(entry);
220 }
221 
222 /**
223  * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache
224  * @key: the hash key
225  * @key_len: the length of the key in bytes
226  *
227  * Description:
228  * The CIPSO tag hashing function.  Returns a 32-bit hash value.
229  *
230  */
cipso_v4_map_cache_hash(const unsigned char * key,u32 key_len)231 static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len)
232 {
233 	return jhash(key, key_len, 0);
234 }
235 
236 /*
237  * Label Mapping Cache Functions
238  */
239 
240 /**
241  * cipso_v4_cache_init - Initialize the CIPSO cache
242  *
243  * Description:
244  * Initializes the CIPSO label mapping cache, this function should be called
245  * before any of the other functions defined in this file.  Returns zero on
246  * success, negative values on error.
247  *
248  */
cipso_v4_cache_init(void)249 static int cipso_v4_cache_init(void)
250 {
251 	u32 iter;
252 
253 	cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS,
254 				 sizeof(struct cipso_v4_map_cache_bkt),
255 				 GFP_KERNEL);
256 	if (cipso_v4_cache == NULL)
257 		return -ENOMEM;
258 
259 	for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
260 		spin_lock_init(&cipso_v4_cache[iter].lock);
261 		cipso_v4_cache[iter].size = 0;
262 		INIT_LIST_HEAD(&cipso_v4_cache[iter].list);
263 	}
264 
265 	return 0;
266 }
267 
268 /**
269  * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache
270  *
271  * Description:
272  * Invalidates and frees any entries in the CIPSO cache.  Returns zero on
273  * success and negative values on failure.
274  *
275  */
cipso_v4_cache_invalidate(void)276 void cipso_v4_cache_invalidate(void)
277 {
278 	struct cipso_v4_map_cache_entry *entry, *tmp_entry;
279 	u32 iter;
280 
281 	for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
282 		spin_lock_bh(&cipso_v4_cache[iter].lock);
283 		list_for_each_entry_safe(entry,
284 					 tmp_entry,
285 					 &cipso_v4_cache[iter].list, list) {
286 			list_del(&entry->list);
287 			cipso_v4_cache_entry_free(entry);
288 		}
289 		cipso_v4_cache[iter].size = 0;
290 		spin_unlock_bh(&cipso_v4_cache[iter].lock);
291 	}
292 
293 	return;
294 }
295 
296 /**
297  * cipso_v4_cache_check - Check the CIPSO cache for a label mapping
298  * @key: the buffer to check
299  * @key_len: buffer length in bytes
300  * @secattr: the security attribute struct to use
301  *
302  * Description:
303  * This function checks the cache to see if a label mapping already exists for
304  * the given key.  If there is a match then the cache is adjusted and the
305  * @secattr struct is populated with the correct LSM security attributes.  The
306  * cache is adjusted in the following manner if the entry is not already the
307  * first in the cache bucket:
308  *
309  *  1. The cache entry's activity counter is incremented
310  *  2. The previous (higher ranking) entry's activity counter is decremented
311  *  3. If the difference between the two activity counters is geater than
312  *     CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped
313  *
314  * Returns zero on success, -ENOENT for a cache miss, and other negative values
315  * on error.
316  *
317  */
cipso_v4_cache_check(const unsigned char * key,u32 key_len,struct netlbl_lsm_secattr * secattr)318 static int cipso_v4_cache_check(const unsigned char *key,
319 				u32 key_len,
320 				struct netlbl_lsm_secattr *secattr)
321 {
322 	u32 bkt;
323 	struct cipso_v4_map_cache_entry *entry;
324 	struct cipso_v4_map_cache_entry *prev_entry = NULL;
325 	u32 hash;
326 
327 	if (!cipso_v4_cache_enabled)
328 		return -ENOENT;
329 
330 	hash = cipso_v4_map_cache_hash(key, key_len);
331 	bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
332 	spin_lock_bh(&cipso_v4_cache[bkt].lock);
333 	list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
334 		if (entry->hash == hash &&
335 		    entry->key_len == key_len &&
336 		    memcmp(entry->key, key, key_len) == 0) {
337 			entry->activity += 1;
338 			atomic_inc(&entry->lsm_data->refcount);
339 			secattr->cache = entry->lsm_data;
340 			secattr->flags |= NETLBL_SECATTR_CACHE;
341 			secattr->type = NETLBL_NLTYPE_CIPSOV4;
342 			if (prev_entry == NULL) {
343 				spin_unlock_bh(&cipso_v4_cache[bkt].lock);
344 				return 0;
345 			}
346 
347 			if (prev_entry->activity > 0)
348 				prev_entry->activity -= 1;
349 			if (entry->activity > prev_entry->activity &&
350 			    entry->activity - prev_entry->activity >
351 			    CIPSO_V4_CACHE_REORDERLIMIT) {
352 				__list_del(entry->list.prev, entry->list.next);
353 				__list_add(&entry->list,
354 					   prev_entry->list.prev,
355 					   &prev_entry->list);
356 			}
357 
358 			spin_unlock_bh(&cipso_v4_cache[bkt].lock);
359 			return 0;
360 		}
361 		prev_entry = entry;
362 	}
363 	spin_unlock_bh(&cipso_v4_cache[bkt].lock);
364 
365 	return -ENOENT;
366 }
367 
368 /**
369  * cipso_v4_cache_add - Add an entry to the CIPSO cache
370  * @skb: the packet
371  * @secattr: the packet's security attributes
372  *
373  * Description:
374  * Add a new entry into the CIPSO label mapping cache.  Add the new entry to
375  * head of the cache bucket's list, if the cache bucket is out of room remove
376  * the last entry in the list first.  It is important to note that there is
377  * currently no checking for duplicate keys.  Returns zero on success,
378  * negative values on failure.
379  *
380  */
cipso_v4_cache_add(const struct sk_buff * skb,const struct netlbl_lsm_secattr * secattr)381 int cipso_v4_cache_add(const struct sk_buff *skb,
382 		       const struct netlbl_lsm_secattr *secattr)
383 {
384 	int ret_val = -EPERM;
385 	u32 bkt;
386 	struct cipso_v4_map_cache_entry *entry = NULL;
387 	struct cipso_v4_map_cache_entry *old_entry = NULL;
388 	unsigned char *cipso_ptr;
389 	u32 cipso_ptr_len;
390 
391 	if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0)
392 		return 0;
393 
394 	cipso_ptr = CIPSO_V4_OPTPTR(skb);
395 	cipso_ptr_len = cipso_ptr[1];
396 
397 	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
398 	if (entry == NULL)
399 		return -ENOMEM;
400 	entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC);
401 	if (entry->key == NULL) {
402 		ret_val = -ENOMEM;
403 		goto cache_add_failure;
404 	}
405 	entry->key_len = cipso_ptr_len;
406 	entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len);
407 	atomic_inc(&secattr->cache->refcount);
408 	entry->lsm_data = secattr->cache;
409 
410 	bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1);
411 	spin_lock_bh(&cipso_v4_cache[bkt].lock);
412 	if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) {
413 		list_add(&entry->list, &cipso_v4_cache[bkt].list);
414 		cipso_v4_cache[bkt].size += 1;
415 	} else {
416 		old_entry = list_entry(cipso_v4_cache[bkt].list.prev,
417 				       struct cipso_v4_map_cache_entry, list);
418 		list_del(&old_entry->list);
419 		list_add(&entry->list, &cipso_v4_cache[bkt].list);
420 		cipso_v4_cache_entry_free(old_entry);
421 	}
422 	spin_unlock_bh(&cipso_v4_cache[bkt].lock);
423 
424 	return 0;
425 
426 cache_add_failure:
427 	if (entry)
428 		cipso_v4_cache_entry_free(entry);
429 	return ret_val;
430 }
431 
432 /*
433  * DOI List Functions
434  */
435 
436 /**
437  * cipso_v4_doi_search - Searches for a DOI definition
438  * @doi: the DOI to search for
439  *
440  * Description:
441  * Search the DOI definition list for a DOI definition with a DOI value that
442  * matches @doi.  The caller is responsibile for calling rcu_read_[un]lock().
443  * Returns a pointer to the DOI definition on success and NULL on failure.
444  */
cipso_v4_doi_search(u32 doi)445 static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi)
446 {
447 	struct cipso_v4_doi *iter;
448 
449 	list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list)
450 		if (iter->doi == doi && atomic_read(&iter->refcount))
451 			return iter;
452 	return NULL;
453 }
454 
455 /**
456  * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine
457  * @doi_def: the DOI structure
458  * @audit_info: NetLabel audit information
459  *
460  * Description:
461  * The caller defines a new DOI for use by the CIPSO engine and calls this
462  * function to add it to the list of acceptable domains.  The caller must
463  * ensure that the mapping table specified in @doi_def->map meets all of the
464  * requirements of the mapping type (see cipso_ipv4.h for details).  Returns
465  * zero on success and non-zero on failure.
466  *
467  */
cipso_v4_doi_add(struct cipso_v4_doi * doi_def,struct netlbl_audit * audit_info)468 int cipso_v4_doi_add(struct cipso_v4_doi *doi_def,
469 		     struct netlbl_audit *audit_info)
470 {
471 	int ret_val = -EINVAL;
472 	u32 iter;
473 	u32 doi;
474 	u32 doi_type;
475 	struct audit_buffer *audit_buf;
476 
477 	doi = doi_def->doi;
478 	doi_type = doi_def->type;
479 
480 	if (doi_def == NULL || doi_def->doi == CIPSO_V4_DOI_UNKNOWN)
481 		goto doi_add_return;
482 	for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) {
483 		switch (doi_def->tags[iter]) {
484 		case CIPSO_V4_TAG_RBITMAP:
485 			break;
486 		case CIPSO_V4_TAG_RANGE:
487 		case CIPSO_V4_TAG_ENUM:
488 			if (doi_def->type != CIPSO_V4_MAP_PASS)
489 				goto doi_add_return;
490 			break;
491 		case CIPSO_V4_TAG_LOCAL:
492 			if (doi_def->type != CIPSO_V4_MAP_LOCAL)
493 				goto doi_add_return;
494 			break;
495 		case CIPSO_V4_TAG_INVALID:
496 			if (iter == 0)
497 				goto doi_add_return;
498 			break;
499 		default:
500 			goto doi_add_return;
501 		}
502 	}
503 
504 	atomic_set(&doi_def->refcount, 1);
505 
506 	spin_lock(&cipso_v4_doi_list_lock);
507 	if (cipso_v4_doi_search(doi_def->doi) != NULL) {
508 		spin_unlock(&cipso_v4_doi_list_lock);
509 		ret_val = -EEXIST;
510 		goto doi_add_return;
511 	}
512 	list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list);
513 	spin_unlock(&cipso_v4_doi_list_lock);
514 	ret_val = 0;
515 
516 doi_add_return:
517 	audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info);
518 	if (audit_buf != NULL) {
519 		const char *type_str;
520 		switch (doi_type) {
521 		case CIPSO_V4_MAP_TRANS:
522 			type_str = "trans";
523 			break;
524 		case CIPSO_V4_MAP_PASS:
525 			type_str = "pass";
526 			break;
527 		case CIPSO_V4_MAP_LOCAL:
528 			type_str = "local";
529 			break;
530 		default:
531 			type_str = "(unknown)";
532 		}
533 		audit_log_format(audit_buf,
534 				 " cipso_doi=%u cipso_type=%s res=%u",
535 				 doi, type_str, ret_val == 0 ? 1 : 0);
536 		audit_log_end(audit_buf);
537 	}
538 
539 	return ret_val;
540 }
541 
542 /**
543  * cipso_v4_doi_free - Frees a DOI definition
544  * @entry: the entry's RCU field
545  *
546  * Description:
547  * This function frees all of the memory associated with a DOI definition.
548  *
549  */
cipso_v4_doi_free(struct cipso_v4_doi * doi_def)550 void cipso_v4_doi_free(struct cipso_v4_doi *doi_def)
551 {
552 	if (doi_def == NULL)
553 		return;
554 
555 	switch (doi_def->type) {
556 	case CIPSO_V4_MAP_TRANS:
557 		kfree(doi_def->map.std->lvl.cipso);
558 		kfree(doi_def->map.std->lvl.local);
559 		kfree(doi_def->map.std->cat.cipso);
560 		kfree(doi_def->map.std->cat.local);
561 		break;
562 	}
563 	kfree(doi_def);
564 }
565 
566 /**
567  * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer
568  * @entry: the entry's RCU field
569  *
570  * Description:
571  * This function is designed to be used as a callback to the call_rcu()
572  * function so that the memory allocated to the DOI definition can be released
573  * safely.
574  *
575  */
cipso_v4_doi_free_rcu(struct rcu_head * entry)576 static void cipso_v4_doi_free_rcu(struct rcu_head *entry)
577 {
578 	struct cipso_v4_doi *doi_def;
579 
580 	doi_def = container_of(entry, struct cipso_v4_doi, rcu);
581 	cipso_v4_doi_free(doi_def);
582 }
583 
584 /**
585  * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine
586  * @doi: the DOI value
587  * @audit_secid: the LSM secid to use in the audit message
588  *
589  * Description:
590  * Removes a DOI definition from the CIPSO engine.  The NetLabel routines will
591  * be called to release their own LSM domain mappings as well as our own
592  * domain list.  Returns zero on success and negative values on failure.
593  *
594  */
cipso_v4_doi_remove(u32 doi,struct netlbl_audit * audit_info)595 int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info)
596 {
597 	int ret_val;
598 	struct cipso_v4_doi *doi_def;
599 	struct audit_buffer *audit_buf;
600 
601 	spin_lock(&cipso_v4_doi_list_lock);
602 	doi_def = cipso_v4_doi_search(doi);
603 	if (doi_def == NULL) {
604 		spin_unlock(&cipso_v4_doi_list_lock);
605 		ret_val = -ENOENT;
606 		goto doi_remove_return;
607 	}
608 	if (!atomic_dec_and_test(&doi_def->refcount)) {
609 		spin_unlock(&cipso_v4_doi_list_lock);
610 		ret_val = -EBUSY;
611 		goto doi_remove_return;
612 	}
613 	list_del_rcu(&doi_def->list);
614 	spin_unlock(&cipso_v4_doi_list_lock);
615 
616 	cipso_v4_cache_invalidate();
617 	call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
618 	ret_val = 0;
619 
620 doi_remove_return:
621 	audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info);
622 	if (audit_buf != NULL) {
623 		audit_log_format(audit_buf,
624 				 " cipso_doi=%u res=%u",
625 				 doi, ret_val == 0 ? 1 : 0);
626 		audit_log_end(audit_buf);
627 	}
628 
629 	return ret_val;
630 }
631 
632 /**
633  * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition
634  * @doi: the DOI value
635  *
636  * Description:
637  * Searches for a valid DOI definition and if one is found it is returned to
638  * the caller.  Otherwise NULL is returned.  The caller must ensure that
639  * rcu_read_lock() is held while accessing the returned definition and the DOI
640  * definition reference count is decremented when the caller is done.
641  *
642  */
cipso_v4_doi_getdef(u32 doi)643 struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
644 {
645 	struct cipso_v4_doi *doi_def;
646 
647 	rcu_read_lock();
648 	doi_def = cipso_v4_doi_search(doi);
649 	if (doi_def == NULL)
650 		goto doi_getdef_return;
651 	if (!atomic_inc_not_zero(&doi_def->refcount))
652 		doi_def = NULL;
653 
654 doi_getdef_return:
655 	rcu_read_unlock();
656 	return doi_def;
657 }
658 
659 /**
660  * cipso_v4_doi_putdef - Releases a reference for the given DOI definition
661  * @doi_def: the DOI definition
662  *
663  * Description:
664  * Releases a DOI definition reference obtained from cipso_v4_doi_getdef().
665  *
666  */
cipso_v4_doi_putdef(struct cipso_v4_doi * doi_def)667 void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def)
668 {
669 	if (doi_def == NULL)
670 		return;
671 
672 	if (!atomic_dec_and_test(&doi_def->refcount))
673 		return;
674 	spin_lock(&cipso_v4_doi_list_lock);
675 	list_del_rcu(&doi_def->list);
676 	spin_unlock(&cipso_v4_doi_list_lock);
677 
678 	cipso_v4_cache_invalidate();
679 	call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
680 }
681 
682 /**
683  * cipso_v4_doi_walk - Iterate through the DOI definitions
684  * @skip_cnt: skip past this number of DOI definitions, updated
685  * @callback: callback for each DOI definition
686  * @cb_arg: argument for the callback function
687  *
688  * Description:
689  * Iterate over the DOI definition list, skipping the first @skip_cnt entries.
690  * For each entry call @callback, if @callback returns a negative value stop
691  * 'walking' through the list and return.  Updates the value in @skip_cnt upon
692  * return.  Returns zero on success, negative values on failure.
693  *
694  */
cipso_v4_doi_walk(u32 * skip_cnt,int (* callback)(struct cipso_v4_doi * doi_def,void * arg),void * cb_arg)695 int cipso_v4_doi_walk(u32 *skip_cnt,
696 		     int (*callback) (struct cipso_v4_doi *doi_def, void *arg),
697 		     void *cb_arg)
698 {
699 	int ret_val = -ENOENT;
700 	u32 doi_cnt = 0;
701 	struct cipso_v4_doi *iter_doi;
702 
703 	rcu_read_lock();
704 	list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
705 		if (atomic_read(&iter_doi->refcount) > 0) {
706 			if (doi_cnt++ < *skip_cnt)
707 				continue;
708 			ret_val = callback(iter_doi, cb_arg);
709 			if (ret_val < 0) {
710 				doi_cnt--;
711 				goto doi_walk_return;
712 			}
713 		}
714 
715 doi_walk_return:
716 	rcu_read_unlock();
717 	*skip_cnt = doi_cnt;
718 	return ret_val;
719 }
720 
721 /*
722  * Label Mapping Functions
723  */
724 
725 /**
726  * cipso_v4_map_lvl_valid - Checks to see if the given level is understood
727  * @doi_def: the DOI definition
728  * @level: the level to check
729  *
730  * Description:
731  * Checks the given level against the given DOI definition and returns a
732  * negative value if the level does not have a valid mapping and a zero value
733  * if the level is defined by the DOI.
734  *
735  */
cipso_v4_map_lvl_valid(const struct cipso_v4_doi * doi_def,u8 level)736 static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
737 {
738 	switch (doi_def->type) {
739 	case CIPSO_V4_MAP_PASS:
740 		return 0;
741 	case CIPSO_V4_MAP_TRANS:
742 		if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL)
743 			return 0;
744 		break;
745 	}
746 
747 	return -EFAULT;
748 }
749 
750 /**
751  * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
752  * @doi_def: the DOI definition
753  * @host_lvl: the host MLS level
754  * @net_lvl: the network/CIPSO MLS level
755  *
756  * Description:
757  * Perform a label mapping to translate a local MLS level to the correct
758  * CIPSO level using the given DOI definition.  Returns zero on success,
759  * negative values otherwise.
760  *
761  */
cipso_v4_map_lvl_hton(const struct cipso_v4_doi * doi_def,u32 host_lvl,u32 * net_lvl)762 static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
763 				 u32 host_lvl,
764 				 u32 *net_lvl)
765 {
766 	switch (doi_def->type) {
767 	case CIPSO_V4_MAP_PASS:
768 		*net_lvl = host_lvl;
769 		return 0;
770 	case CIPSO_V4_MAP_TRANS:
771 		if (host_lvl < doi_def->map.std->lvl.local_size &&
772 		    doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) {
773 			*net_lvl = doi_def->map.std->lvl.local[host_lvl];
774 			return 0;
775 		}
776 		return -EPERM;
777 	}
778 
779 	return -EINVAL;
780 }
781 
782 /**
783  * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
784  * @doi_def: the DOI definition
785  * @net_lvl: the network/CIPSO MLS level
786  * @host_lvl: the host MLS level
787  *
788  * Description:
789  * Perform a label mapping to translate a CIPSO level to the correct local MLS
790  * level using the given DOI definition.  Returns zero on success, negative
791  * values otherwise.
792  *
793  */
cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi * doi_def,u32 net_lvl,u32 * host_lvl)794 static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
795 				 u32 net_lvl,
796 				 u32 *host_lvl)
797 {
798 	struct cipso_v4_std_map_tbl *map_tbl;
799 
800 	switch (doi_def->type) {
801 	case CIPSO_V4_MAP_PASS:
802 		*host_lvl = net_lvl;
803 		return 0;
804 	case CIPSO_V4_MAP_TRANS:
805 		map_tbl = doi_def->map.std;
806 		if (net_lvl < map_tbl->lvl.cipso_size &&
807 		    map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
808 			*host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
809 			return 0;
810 		}
811 		return -EPERM;
812 	}
813 
814 	return -EINVAL;
815 }
816 
817 /**
818  * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
819  * @doi_def: the DOI definition
820  * @bitmap: category bitmap
821  * @bitmap_len: bitmap length in bytes
822  *
823  * Description:
824  * Checks the given category bitmap against the given DOI definition and
825  * returns a negative value if any of the categories in the bitmap do not have
826  * a valid mapping and a zero value if all of the categories are valid.
827  *
828  */
cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi * doi_def,const unsigned char * bitmap,u32 bitmap_len)829 static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
830 				      const unsigned char *bitmap,
831 				      u32 bitmap_len)
832 {
833 	int cat = -1;
834 	u32 bitmap_len_bits = bitmap_len * 8;
835 	u32 cipso_cat_size;
836 	u32 *cipso_array;
837 
838 	switch (doi_def->type) {
839 	case CIPSO_V4_MAP_PASS:
840 		return 0;
841 	case CIPSO_V4_MAP_TRANS:
842 		cipso_cat_size = doi_def->map.std->cat.cipso_size;
843 		cipso_array = doi_def->map.std->cat.cipso;
844 		for (;;) {
845 			cat = cipso_v4_bitmap_walk(bitmap,
846 						   bitmap_len_bits,
847 						   cat + 1,
848 						   1);
849 			if (cat < 0)
850 				break;
851 			if (cat >= cipso_cat_size ||
852 			    cipso_array[cat] >= CIPSO_V4_INV_CAT)
853 				return -EFAULT;
854 		}
855 
856 		if (cat == -1)
857 			return 0;
858 		break;
859 	}
860 
861 	return -EFAULT;
862 }
863 
864 /**
865  * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
866  * @doi_def: the DOI definition
867  * @secattr: the security attributes
868  * @net_cat: the zero'd out category bitmap in network/CIPSO format
869  * @net_cat_len: the length of the CIPSO bitmap in bytes
870  *
871  * Description:
872  * Perform a label mapping to translate a local MLS category bitmap to the
873  * correct CIPSO bitmap using the given DOI definition.  Returns the minimum
874  * size in bytes of the network bitmap on success, negative values otherwise.
875  *
876  */
cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr,unsigned char * net_cat,u32 net_cat_len)877 static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
878 				     const struct netlbl_lsm_secattr *secattr,
879 				     unsigned char *net_cat,
880 				     u32 net_cat_len)
881 {
882 	int host_spot = -1;
883 	u32 net_spot = CIPSO_V4_INV_CAT;
884 	u32 net_spot_max = 0;
885 	u32 net_clen_bits = net_cat_len * 8;
886 	u32 host_cat_size = 0;
887 	u32 *host_cat_array = NULL;
888 
889 	if (doi_def->type == CIPSO_V4_MAP_TRANS) {
890 		host_cat_size = doi_def->map.std->cat.local_size;
891 		host_cat_array = doi_def->map.std->cat.local;
892 	}
893 
894 	for (;;) {
895 		host_spot = netlbl_secattr_catmap_walk(secattr->attr.mls.cat,
896 						       host_spot + 1);
897 		if (host_spot < 0)
898 			break;
899 
900 		switch (doi_def->type) {
901 		case CIPSO_V4_MAP_PASS:
902 			net_spot = host_spot;
903 			break;
904 		case CIPSO_V4_MAP_TRANS:
905 			if (host_spot >= host_cat_size)
906 				return -EPERM;
907 			net_spot = host_cat_array[host_spot];
908 			if (net_spot >= CIPSO_V4_INV_CAT)
909 				return -EPERM;
910 			break;
911 		}
912 		if (net_spot >= net_clen_bits)
913 			return -ENOSPC;
914 		cipso_v4_bitmap_setbit(net_cat, net_spot, 1);
915 
916 		if (net_spot > net_spot_max)
917 			net_spot_max = net_spot;
918 	}
919 
920 	if (++net_spot_max % 8)
921 		return net_spot_max / 8 + 1;
922 	return net_spot_max / 8;
923 }
924 
925 /**
926  * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host
927  * @doi_def: the DOI definition
928  * @net_cat: the category bitmap in network/CIPSO format
929  * @net_cat_len: the length of the CIPSO bitmap in bytes
930  * @secattr: the security attributes
931  *
932  * Description:
933  * Perform a label mapping to translate a CIPSO bitmap to the correct local
934  * MLS category bitmap using the given DOI definition.  Returns zero on
935  * success, negative values on failure.
936  *
937  */
cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi * doi_def,const unsigned char * net_cat,u32 net_cat_len,struct netlbl_lsm_secattr * secattr)938 static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
939 				     const unsigned char *net_cat,
940 				     u32 net_cat_len,
941 				     struct netlbl_lsm_secattr *secattr)
942 {
943 	int ret_val;
944 	int net_spot = -1;
945 	u32 host_spot = CIPSO_V4_INV_CAT;
946 	u32 net_clen_bits = net_cat_len * 8;
947 	u32 net_cat_size = 0;
948 	u32 *net_cat_array = NULL;
949 
950 	if (doi_def->type == CIPSO_V4_MAP_TRANS) {
951 		net_cat_size = doi_def->map.std->cat.cipso_size;
952 		net_cat_array = doi_def->map.std->cat.cipso;
953 	}
954 
955 	for (;;) {
956 		net_spot = cipso_v4_bitmap_walk(net_cat,
957 						net_clen_bits,
958 						net_spot + 1,
959 						1);
960 		if (net_spot < 0) {
961 			if (net_spot == -2)
962 				return -EFAULT;
963 			return 0;
964 		}
965 
966 		switch (doi_def->type) {
967 		case CIPSO_V4_MAP_PASS:
968 			host_spot = net_spot;
969 			break;
970 		case CIPSO_V4_MAP_TRANS:
971 			if (net_spot >= net_cat_size)
972 				return -EPERM;
973 			host_spot = net_cat_array[net_spot];
974 			if (host_spot >= CIPSO_V4_INV_CAT)
975 				return -EPERM;
976 			break;
977 		}
978 		ret_val = netlbl_secattr_catmap_setbit(secattr->attr.mls.cat,
979 						       host_spot,
980 						       GFP_ATOMIC);
981 		if (ret_val != 0)
982 			return ret_val;
983 	}
984 
985 	return -EINVAL;
986 }
987 
988 /**
989  * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid
990  * @doi_def: the DOI definition
991  * @enumcat: category list
992  * @enumcat_len: length of the category list in bytes
993  *
994  * Description:
995  * Checks the given categories against the given DOI definition and returns a
996  * negative value if any of the categories do not have a valid mapping and a
997  * zero value if all of the categories are valid.
998  *
999  */
cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi * doi_def,const unsigned char * enumcat,u32 enumcat_len)1000 static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def,
1001 				       const unsigned char *enumcat,
1002 				       u32 enumcat_len)
1003 {
1004 	u16 cat;
1005 	int cat_prev = -1;
1006 	u32 iter;
1007 
1008 	if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01)
1009 		return -EFAULT;
1010 
1011 	for (iter = 0; iter < enumcat_len; iter += 2) {
1012 		cat = get_unaligned_be16(&enumcat[iter]);
1013 		if (cat <= cat_prev)
1014 			return -EFAULT;
1015 		cat_prev = cat;
1016 	}
1017 
1018 	return 0;
1019 }
1020 
1021 /**
1022  * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network
1023  * @doi_def: the DOI definition
1024  * @secattr: the security attributes
1025  * @net_cat: the zero'd out category list in network/CIPSO format
1026  * @net_cat_len: the length of the CIPSO category list in bytes
1027  *
1028  * Description:
1029  * Perform a label mapping to translate a local MLS category bitmap to the
1030  * correct CIPSO category list using the given DOI definition.   Returns the
1031  * size in bytes of the network category bitmap on success, negative values
1032  * otherwise.
1033  *
1034  */
cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr,unsigned char * net_cat,u32 net_cat_len)1035 static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def,
1036 				      const struct netlbl_lsm_secattr *secattr,
1037 				      unsigned char *net_cat,
1038 				      u32 net_cat_len)
1039 {
1040 	int cat = -1;
1041 	u32 cat_iter = 0;
1042 
1043 	for (;;) {
1044 		cat = netlbl_secattr_catmap_walk(secattr->attr.mls.cat,
1045 						 cat + 1);
1046 		if (cat < 0)
1047 			break;
1048 		if ((cat_iter + 2) > net_cat_len)
1049 			return -ENOSPC;
1050 
1051 		*((__be16 *)&net_cat[cat_iter]) = htons(cat);
1052 		cat_iter += 2;
1053 	}
1054 
1055 	return cat_iter;
1056 }
1057 
1058 /**
1059  * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host
1060  * @doi_def: the DOI definition
1061  * @net_cat: the category list in network/CIPSO format
1062  * @net_cat_len: the length of the CIPSO bitmap in bytes
1063  * @secattr: the security attributes
1064  *
1065  * Description:
1066  * Perform a label mapping to translate a CIPSO category list to the correct
1067  * local MLS category bitmap using the given DOI definition.  Returns zero on
1068  * success, negative values on failure.
1069  *
1070  */
cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi * doi_def,const unsigned char * net_cat,u32 net_cat_len,struct netlbl_lsm_secattr * secattr)1071 static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def,
1072 				      const unsigned char *net_cat,
1073 				      u32 net_cat_len,
1074 				      struct netlbl_lsm_secattr *secattr)
1075 {
1076 	int ret_val;
1077 	u32 iter;
1078 
1079 	for (iter = 0; iter < net_cat_len; iter += 2) {
1080 		ret_val = netlbl_secattr_catmap_setbit(secattr->attr.mls.cat,
1081 				get_unaligned_be16(&net_cat[iter]),
1082 				GFP_ATOMIC);
1083 		if (ret_val != 0)
1084 			return ret_val;
1085 	}
1086 
1087 	return 0;
1088 }
1089 
1090 /**
1091  * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid
1092  * @doi_def: the DOI definition
1093  * @rngcat: category list
1094  * @rngcat_len: length of the category list in bytes
1095  *
1096  * Description:
1097  * Checks the given categories against the given DOI definition and returns a
1098  * negative value if any of the categories do not have a valid mapping and a
1099  * zero value if all of the categories are valid.
1100  *
1101  */
cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi * doi_def,const unsigned char * rngcat,u32 rngcat_len)1102 static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def,
1103 				      const unsigned char *rngcat,
1104 				      u32 rngcat_len)
1105 {
1106 	u16 cat_high;
1107 	u16 cat_low;
1108 	u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1;
1109 	u32 iter;
1110 
1111 	if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01)
1112 		return -EFAULT;
1113 
1114 	for (iter = 0; iter < rngcat_len; iter += 4) {
1115 		cat_high = get_unaligned_be16(&rngcat[iter]);
1116 		if ((iter + 4) <= rngcat_len)
1117 			cat_low = get_unaligned_be16(&rngcat[iter + 2]);
1118 		else
1119 			cat_low = 0;
1120 
1121 		if (cat_high > cat_prev)
1122 			return -EFAULT;
1123 
1124 		cat_prev = cat_low;
1125 	}
1126 
1127 	return 0;
1128 }
1129 
1130 /**
1131  * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network
1132  * @doi_def: the DOI definition
1133  * @secattr: the security attributes
1134  * @net_cat: the zero'd out category list in network/CIPSO format
1135  * @net_cat_len: the length of the CIPSO category list in bytes
1136  *
1137  * Description:
1138  * Perform a label mapping to translate a local MLS category bitmap to the
1139  * correct CIPSO category list using the given DOI definition.   Returns the
1140  * size in bytes of the network category bitmap on success, negative values
1141  * otherwise.
1142  *
1143  */
cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr,unsigned char * net_cat,u32 net_cat_len)1144 static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def,
1145 				     const struct netlbl_lsm_secattr *secattr,
1146 				     unsigned char *net_cat,
1147 				     u32 net_cat_len)
1148 {
1149 	int iter = -1;
1150 	u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2];
1151 	u32 array_cnt = 0;
1152 	u32 cat_size = 0;
1153 
1154 	/* make sure we don't overflow the 'array[]' variable */
1155 	if (net_cat_len >
1156 	    (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN))
1157 		return -ENOSPC;
1158 
1159 	for (;;) {
1160 		iter = netlbl_secattr_catmap_walk(secattr->attr.mls.cat,
1161 						  iter + 1);
1162 		if (iter < 0)
1163 			break;
1164 		cat_size += (iter == 0 ? 0 : sizeof(u16));
1165 		if (cat_size > net_cat_len)
1166 			return -ENOSPC;
1167 		array[array_cnt++] = iter;
1168 
1169 		iter = netlbl_secattr_catmap_walk_rng(secattr->attr.mls.cat,
1170 						      iter);
1171 		if (iter < 0)
1172 			return -EFAULT;
1173 		cat_size += sizeof(u16);
1174 		if (cat_size > net_cat_len)
1175 			return -ENOSPC;
1176 		array[array_cnt++] = iter;
1177 	}
1178 
1179 	for (iter = 0; array_cnt > 0;) {
1180 		*((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]);
1181 		iter += 2;
1182 		array_cnt--;
1183 		if (array[array_cnt] != 0) {
1184 			*((__be16 *)&net_cat[iter]) = htons(array[array_cnt]);
1185 			iter += 2;
1186 		}
1187 	}
1188 
1189 	return cat_size;
1190 }
1191 
1192 /**
1193  * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host
1194  * @doi_def: the DOI definition
1195  * @net_cat: the category list in network/CIPSO format
1196  * @net_cat_len: the length of the CIPSO bitmap in bytes
1197  * @secattr: the security attributes
1198  *
1199  * Description:
1200  * Perform a label mapping to translate a CIPSO category list to the correct
1201  * local MLS category bitmap using the given DOI definition.  Returns zero on
1202  * success, negative values on failure.
1203  *
1204  */
cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi * doi_def,const unsigned char * net_cat,u32 net_cat_len,struct netlbl_lsm_secattr * secattr)1205 static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def,
1206 				     const unsigned char *net_cat,
1207 				     u32 net_cat_len,
1208 				     struct netlbl_lsm_secattr *secattr)
1209 {
1210 	int ret_val;
1211 	u32 net_iter;
1212 	u16 cat_low;
1213 	u16 cat_high;
1214 
1215 	for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) {
1216 		cat_high = get_unaligned_be16(&net_cat[net_iter]);
1217 		if ((net_iter + 4) <= net_cat_len)
1218 			cat_low = get_unaligned_be16(&net_cat[net_iter + 2]);
1219 		else
1220 			cat_low = 0;
1221 
1222 		ret_val = netlbl_secattr_catmap_setrng(secattr->attr.mls.cat,
1223 						       cat_low,
1224 						       cat_high,
1225 						       GFP_ATOMIC);
1226 		if (ret_val != 0)
1227 			return ret_val;
1228 	}
1229 
1230 	return 0;
1231 }
1232 
1233 /*
1234  * Protocol Handling Functions
1235  */
1236 
1237 /**
1238  * cipso_v4_gentag_hdr - Generate a CIPSO option header
1239  * @doi_def: the DOI definition
1240  * @len: the total tag length in bytes, not including this header
1241  * @buf: the CIPSO option buffer
1242  *
1243  * Description:
1244  * Write a CIPSO header into the beginning of @buffer.
1245  *
1246  */
cipso_v4_gentag_hdr(const struct cipso_v4_doi * doi_def,unsigned char * buf,u32 len)1247 static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
1248 				unsigned char *buf,
1249 				u32 len)
1250 {
1251 	buf[0] = IPOPT_CIPSO;
1252 	buf[1] = CIPSO_V4_HDR_LEN + len;
1253 	*(__be32 *)&buf[2] = htonl(doi_def->doi);
1254 }
1255 
1256 /**
1257  * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1)
1258  * @doi_def: the DOI definition
1259  * @secattr: the security attributes
1260  * @buffer: the option buffer
1261  * @buffer_len: length of buffer in bytes
1262  *
1263  * Description:
1264  * Generate a CIPSO option using the restricted bitmap tag, tag type #1.  The
1265  * actual buffer length may be larger than the indicated size due to
1266  * translation between host and network category bitmaps.  Returns the size of
1267  * the tag on success, negative values on failure.
1268  *
1269  */
cipso_v4_gentag_rbm(const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr,unsigned char * buffer,u32 buffer_len)1270 static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
1271 			       const struct netlbl_lsm_secattr *secattr,
1272 			       unsigned char *buffer,
1273 			       u32 buffer_len)
1274 {
1275 	int ret_val;
1276 	u32 tag_len;
1277 	u32 level;
1278 
1279 	if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
1280 		return -EPERM;
1281 
1282 	ret_val = cipso_v4_map_lvl_hton(doi_def,
1283 					secattr->attr.mls.lvl,
1284 					&level);
1285 	if (ret_val != 0)
1286 		return ret_val;
1287 
1288 	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1289 		ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
1290 						    secattr,
1291 						    &buffer[4],
1292 						    buffer_len - 4);
1293 		if (ret_val < 0)
1294 			return ret_val;
1295 
1296 		/* This will send packets using the "optimized" format when
1297 		 * possibile as specified in  section 3.4.2.6 of the
1298 		 * CIPSO draft. */
1299 		if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10)
1300 			tag_len = 14;
1301 		else
1302 			tag_len = 4 + ret_val;
1303 	} else
1304 		tag_len = 4;
1305 
1306 	buffer[0] = CIPSO_V4_TAG_RBITMAP;
1307 	buffer[1] = tag_len;
1308 	buffer[3] = level;
1309 
1310 	return tag_len;
1311 }
1312 
1313 /**
1314  * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag
1315  * @doi_def: the DOI definition
1316  * @tag: the CIPSO tag
1317  * @secattr: the security attributes
1318  *
1319  * Description:
1320  * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security
1321  * attributes in @secattr.  Return zero on success, negatives values on
1322  * failure.
1323  *
1324  */
cipso_v4_parsetag_rbm(const struct cipso_v4_doi * doi_def,const unsigned char * tag,struct netlbl_lsm_secattr * secattr)1325 static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
1326 				 const unsigned char *tag,
1327 				 struct netlbl_lsm_secattr *secattr)
1328 {
1329 	int ret_val;
1330 	u8 tag_len = tag[1];
1331 	u32 level;
1332 
1333 	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1334 	if (ret_val != 0)
1335 		return ret_val;
1336 	secattr->attr.mls.lvl = level;
1337 	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1338 
1339 	if (tag_len > 4) {
1340 		secattr->attr.mls.cat =
1341 		                       netlbl_secattr_catmap_alloc(GFP_ATOMIC);
1342 		if (secattr->attr.mls.cat == NULL)
1343 			return -ENOMEM;
1344 
1345 		ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
1346 						    &tag[4],
1347 						    tag_len - 4,
1348 						    secattr);
1349 		if (ret_val != 0) {
1350 			netlbl_secattr_catmap_free(secattr->attr.mls.cat);
1351 			return ret_val;
1352 		}
1353 
1354 		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1355 	}
1356 
1357 	return 0;
1358 }
1359 
1360 /**
1361  * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2)
1362  * @doi_def: the DOI definition
1363  * @secattr: the security attributes
1364  * @buffer: the option buffer
1365  * @buffer_len: length of buffer in bytes
1366  *
1367  * Description:
1368  * Generate a CIPSO option using the enumerated tag, tag type #2.  Returns the
1369  * size of the tag on success, negative values on failure.
1370  *
1371  */
cipso_v4_gentag_enum(const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr,unsigned char * buffer,u32 buffer_len)1372 static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def,
1373 				const struct netlbl_lsm_secattr *secattr,
1374 				unsigned char *buffer,
1375 				u32 buffer_len)
1376 {
1377 	int ret_val;
1378 	u32 tag_len;
1379 	u32 level;
1380 
1381 	if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1382 		return -EPERM;
1383 
1384 	ret_val = cipso_v4_map_lvl_hton(doi_def,
1385 					secattr->attr.mls.lvl,
1386 					&level);
1387 	if (ret_val != 0)
1388 		return ret_val;
1389 
1390 	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1391 		ret_val = cipso_v4_map_cat_enum_hton(doi_def,
1392 						     secattr,
1393 						     &buffer[4],
1394 						     buffer_len - 4);
1395 		if (ret_val < 0)
1396 			return ret_val;
1397 
1398 		tag_len = 4 + ret_val;
1399 	} else
1400 		tag_len = 4;
1401 
1402 	buffer[0] = CIPSO_V4_TAG_ENUM;
1403 	buffer[1] = tag_len;
1404 	buffer[3] = level;
1405 
1406 	return tag_len;
1407 }
1408 
1409 /**
1410  * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag
1411  * @doi_def: the DOI definition
1412  * @tag: the CIPSO tag
1413  * @secattr: the security attributes
1414  *
1415  * Description:
1416  * Parse a CIPSO enumerated tag (tag type #2) and return the security
1417  * attributes in @secattr.  Return zero on success, negatives values on
1418  * failure.
1419  *
1420  */
cipso_v4_parsetag_enum(const struct cipso_v4_doi * doi_def,const unsigned char * tag,struct netlbl_lsm_secattr * secattr)1421 static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def,
1422 				  const unsigned char *tag,
1423 				  struct netlbl_lsm_secattr *secattr)
1424 {
1425 	int ret_val;
1426 	u8 tag_len = tag[1];
1427 	u32 level;
1428 
1429 	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1430 	if (ret_val != 0)
1431 		return ret_val;
1432 	secattr->attr.mls.lvl = level;
1433 	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1434 
1435 	if (tag_len > 4) {
1436 		secattr->attr.mls.cat =
1437 			               netlbl_secattr_catmap_alloc(GFP_ATOMIC);
1438 		if (secattr->attr.mls.cat == NULL)
1439 			return -ENOMEM;
1440 
1441 		ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
1442 						     &tag[4],
1443 						     tag_len - 4,
1444 						     secattr);
1445 		if (ret_val != 0) {
1446 			netlbl_secattr_catmap_free(secattr->attr.mls.cat);
1447 			return ret_val;
1448 		}
1449 
1450 		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1451 	}
1452 
1453 	return 0;
1454 }
1455 
1456 /**
1457  * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5)
1458  * @doi_def: the DOI definition
1459  * @secattr: the security attributes
1460  * @buffer: the option buffer
1461  * @buffer_len: length of buffer in bytes
1462  *
1463  * Description:
1464  * Generate a CIPSO option using the ranged tag, tag type #5.  Returns the
1465  * size of the tag on success, negative values on failure.
1466  *
1467  */
cipso_v4_gentag_rng(const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr,unsigned char * buffer,u32 buffer_len)1468 static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def,
1469 			       const struct netlbl_lsm_secattr *secattr,
1470 			       unsigned char *buffer,
1471 			       u32 buffer_len)
1472 {
1473 	int ret_val;
1474 	u32 tag_len;
1475 	u32 level;
1476 
1477 	if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1478 		return -EPERM;
1479 
1480 	ret_val = cipso_v4_map_lvl_hton(doi_def,
1481 					secattr->attr.mls.lvl,
1482 					&level);
1483 	if (ret_val != 0)
1484 		return ret_val;
1485 
1486 	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1487 		ret_val = cipso_v4_map_cat_rng_hton(doi_def,
1488 						    secattr,
1489 						    &buffer[4],
1490 						    buffer_len - 4);
1491 		if (ret_val < 0)
1492 			return ret_val;
1493 
1494 		tag_len = 4 + ret_val;
1495 	} else
1496 		tag_len = 4;
1497 
1498 	buffer[0] = CIPSO_V4_TAG_RANGE;
1499 	buffer[1] = tag_len;
1500 	buffer[3] = level;
1501 
1502 	return tag_len;
1503 }
1504 
1505 /**
1506  * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag
1507  * @doi_def: the DOI definition
1508  * @tag: the CIPSO tag
1509  * @secattr: the security attributes
1510  *
1511  * Description:
1512  * Parse a CIPSO ranged tag (tag type #5) and return the security attributes
1513  * in @secattr.  Return zero on success, negatives values on failure.
1514  *
1515  */
cipso_v4_parsetag_rng(const struct cipso_v4_doi * doi_def,const unsigned char * tag,struct netlbl_lsm_secattr * secattr)1516 static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def,
1517 				 const unsigned char *tag,
1518 				 struct netlbl_lsm_secattr *secattr)
1519 {
1520 	int ret_val;
1521 	u8 tag_len = tag[1];
1522 	u32 level;
1523 
1524 	ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1525 	if (ret_val != 0)
1526 		return ret_val;
1527 	secattr->attr.mls.lvl = level;
1528 	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1529 
1530 	if (tag_len > 4) {
1531 		secattr->attr.mls.cat =
1532 			               netlbl_secattr_catmap_alloc(GFP_ATOMIC);
1533 		if (secattr->attr.mls.cat == NULL)
1534 			return -ENOMEM;
1535 
1536 		ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
1537 						    &tag[4],
1538 						    tag_len - 4,
1539 						    secattr);
1540 		if (ret_val != 0) {
1541 			netlbl_secattr_catmap_free(secattr->attr.mls.cat);
1542 			return ret_val;
1543 		}
1544 
1545 		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1546 	}
1547 
1548 	return 0;
1549 }
1550 
1551 /**
1552  * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard)
1553  * @doi_def: the DOI definition
1554  * @secattr: the security attributes
1555  * @buffer: the option buffer
1556  * @buffer_len: length of buffer in bytes
1557  *
1558  * Description:
1559  * Generate a CIPSO option using the local tag.  Returns the size of the tag
1560  * on success, negative values on failure.
1561  *
1562  */
cipso_v4_gentag_loc(const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr,unsigned char * buffer,u32 buffer_len)1563 static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
1564 			       const struct netlbl_lsm_secattr *secattr,
1565 			       unsigned char *buffer,
1566 			       u32 buffer_len)
1567 {
1568 	if (!(secattr->flags & NETLBL_SECATTR_SECID))
1569 		return -EPERM;
1570 
1571 	buffer[0] = CIPSO_V4_TAG_LOCAL;
1572 	buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
1573 	*(u32 *)&buffer[2] = secattr->attr.secid;
1574 
1575 	return CIPSO_V4_TAG_LOC_BLEN;
1576 }
1577 
1578 /**
1579  * cipso_v4_parsetag_loc - Parse a CIPSO local tag
1580  * @doi_def: the DOI definition
1581  * @tag: the CIPSO tag
1582  * @secattr: the security attributes
1583  *
1584  * Description:
1585  * Parse a CIPSO local tag and return the security attributes in @secattr.
1586  * Return zero on success, negatives values on failure.
1587  *
1588  */
cipso_v4_parsetag_loc(const struct cipso_v4_doi * doi_def,const unsigned char * tag,struct netlbl_lsm_secattr * secattr)1589 static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
1590 				 const unsigned char *tag,
1591 				 struct netlbl_lsm_secattr *secattr)
1592 {
1593 	secattr->attr.secid = *(u32 *)&tag[2];
1594 	secattr->flags |= NETLBL_SECATTR_SECID;
1595 
1596 	return 0;
1597 }
1598 
1599 /**
1600  * cipso_v4_validate - Validate a CIPSO option
1601  * @option: the start of the option, on error it is set to point to the error
1602  *
1603  * Description:
1604  * This routine is called to validate a CIPSO option, it checks all of the
1605  * fields to ensure that they are at least valid, see the draft snippet below
1606  * for details.  If the option is valid then a zero value is returned and
1607  * the value of @option is unchanged.  If the option is invalid then a
1608  * non-zero value is returned and @option is adjusted to point to the
1609  * offending portion of the option.  From the IETF draft ...
1610  *
1611  *  "If any field within the CIPSO options, such as the DOI identifier, is not
1612  *   recognized the IP datagram is discarded and an ICMP 'parameter problem'
1613  *   (type 12) is generated and returned.  The ICMP code field is set to 'bad
1614  *   parameter' (code 0) and the pointer is set to the start of the CIPSO field
1615  *   that is unrecognized."
1616  *
1617  */
cipso_v4_validate(const struct sk_buff * skb,unsigned char ** option)1618 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
1619 {
1620 	unsigned char *opt = *option;
1621 	unsigned char *tag;
1622 	unsigned char opt_iter;
1623 	unsigned char err_offset = 0;
1624 	u8 opt_len;
1625 	u8 tag_len;
1626 	struct cipso_v4_doi *doi_def = NULL;
1627 	u32 tag_iter;
1628 
1629 	/* caller already checks for length values that are too large */
1630 	opt_len = opt[1];
1631 	if (opt_len < 8) {
1632 		err_offset = 1;
1633 		goto validate_return;
1634 	}
1635 
1636 	rcu_read_lock();
1637 	doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2]));
1638 	if (doi_def == NULL) {
1639 		err_offset = 2;
1640 		goto validate_return_locked;
1641 	}
1642 
1643 	opt_iter = CIPSO_V4_HDR_LEN;
1644 	tag = opt + opt_iter;
1645 	while (opt_iter < opt_len) {
1646 		for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
1647 			if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
1648 			    ++tag_iter == CIPSO_V4_TAG_MAXCNT) {
1649 				err_offset = opt_iter;
1650 				goto validate_return_locked;
1651 			}
1652 
1653 		tag_len = tag[1];
1654 		if (tag_len > (opt_len - opt_iter)) {
1655 			err_offset = opt_iter + 1;
1656 			goto validate_return_locked;
1657 		}
1658 
1659 		switch (tag[0]) {
1660 		case CIPSO_V4_TAG_RBITMAP:
1661 			if (tag_len < CIPSO_V4_TAG_RBM_BLEN) {
1662 				err_offset = opt_iter + 1;
1663 				goto validate_return_locked;
1664 			}
1665 
1666 			/* We are already going to do all the verification
1667 			 * necessary at the socket layer so from our point of
1668 			 * view it is safe to turn these checks off (and less
1669 			 * work), however, the CIPSO draft says we should do
1670 			 * all the CIPSO validations here but it doesn't
1671 			 * really specify _exactly_ what we need to validate
1672 			 * ... so, just make it a sysctl tunable. */
1673 			if (cipso_v4_rbm_strictvalid) {
1674 				if (cipso_v4_map_lvl_valid(doi_def,
1675 							   tag[3]) < 0) {
1676 					err_offset = opt_iter + 3;
1677 					goto validate_return_locked;
1678 				}
1679 				if (tag_len > CIPSO_V4_TAG_RBM_BLEN &&
1680 				    cipso_v4_map_cat_rbm_valid(doi_def,
1681 							    &tag[4],
1682 							    tag_len - 4) < 0) {
1683 					err_offset = opt_iter + 4;
1684 					goto validate_return_locked;
1685 				}
1686 			}
1687 			break;
1688 		case CIPSO_V4_TAG_ENUM:
1689 			if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) {
1690 				err_offset = opt_iter + 1;
1691 				goto validate_return_locked;
1692 			}
1693 
1694 			if (cipso_v4_map_lvl_valid(doi_def,
1695 						   tag[3]) < 0) {
1696 				err_offset = opt_iter + 3;
1697 				goto validate_return_locked;
1698 			}
1699 			if (tag_len > CIPSO_V4_TAG_ENUM_BLEN &&
1700 			    cipso_v4_map_cat_enum_valid(doi_def,
1701 							&tag[4],
1702 							tag_len - 4) < 0) {
1703 				err_offset = opt_iter + 4;
1704 				goto validate_return_locked;
1705 			}
1706 			break;
1707 		case CIPSO_V4_TAG_RANGE:
1708 			if (tag_len < CIPSO_V4_TAG_RNG_BLEN) {
1709 				err_offset = opt_iter + 1;
1710 				goto validate_return_locked;
1711 			}
1712 
1713 			if (cipso_v4_map_lvl_valid(doi_def,
1714 						   tag[3]) < 0) {
1715 				err_offset = opt_iter + 3;
1716 				goto validate_return_locked;
1717 			}
1718 			if (tag_len > CIPSO_V4_TAG_RNG_BLEN &&
1719 			    cipso_v4_map_cat_rng_valid(doi_def,
1720 						       &tag[4],
1721 						       tag_len - 4) < 0) {
1722 				err_offset = opt_iter + 4;
1723 				goto validate_return_locked;
1724 			}
1725 			break;
1726 		case CIPSO_V4_TAG_LOCAL:
1727 			/* This is a non-standard tag that we only allow for
1728 			 * local connections, so if the incoming interface is
1729 			 * not the loopback device drop the packet. */
1730 			if (!(skb->dev->flags & IFF_LOOPBACK)) {
1731 				err_offset = opt_iter;
1732 				goto validate_return_locked;
1733 			}
1734 			if (tag_len != CIPSO_V4_TAG_LOC_BLEN) {
1735 				err_offset = opt_iter + 1;
1736 				goto validate_return_locked;
1737 			}
1738 			break;
1739 		default:
1740 			err_offset = opt_iter;
1741 			goto validate_return_locked;
1742 		}
1743 
1744 		tag += tag_len;
1745 		opt_iter += tag_len;
1746 	}
1747 
1748 validate_return_locked:
1749 	rcu_read_unlock();
1750 validate_return:
1751 	*option = opt + err_offset;
1752 	return err_offset;
1753 }
1754 
1755 /**
1756  * cipso_v4_error - Send the correct reponse for a bad packet
1757  * @skb: the packet
1758  * @error: the error code
1759  * @gateway: CIPSO gateway flag
1760  *
1761  * Description:
1762  * Based on the error code given in @error, send an ICMP error message back to
1763  * the originating host.  From the IETF draft ...
1764  *
1765  *  "If the contents of the CIPSO [option] are valid but the security label is
1766  *   outside of the configured host or port label range, the datagram is
1767  *   discarded and an ICMP 'destination unreachable' (type 3) is generated and
1768  *   returned.  The code field of the ICMP is set to 'communication with
1769  *   destination network administratively prohibited' (code 9) or to
1770  *   'communication with destination host administratively prohibited'
1771  *   (code 10).  The value of the code is dependent on whether the originator
1772  *   of the ICMP message is acting as a CIPSO host or a CIPSO gateway.  The
1773  *   recipient of the ICMP message MUST be able to handle either value.  The
1774  *   same procedure is performed if a CIPSO [option] can not be added to an
1775  *   IP packet because it is too large to fit in the IP options area."
1776  *
1777  *  "If the error is triggered by receipt of an ICMP message, the message is
1778  *   discarded and no response is permitted (consistent with general ICMP
1779  *   processing rules)."
1780  *
1781  */
cipso_v4_error(struct sk_buff * skb,int error,u32 gateway)1782 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
1783 {
1784 	if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
1785 		return;
1786 
1787 	if (gateway)
1788 		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
1789 	else
1790 		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
1791 }
1792 
1793 /**
1794  * cipso_v4_genopt - Generate a CIPSO option
1795  * @buf: the option buffer
1796  * @buf_len: the size of opt_buf
1797  * @doi_def: the CIPSO DOI to use
1798  * @secattr: the security attributes
1799  *
1800  * Description:
1801  * Generate a CIPSO option using the DOI definition and security attributes
1802  * passed to the function.  Returns the length of the option on success and
1803  * negative values on failure.
1804  *
1805  */
cipso_v4_genopt(unsigned char * buf,u32 buf_len,const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr)1806 static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
1807 			   const struct cipso_v4_doi *doi_def,
1808 			   const struct netlbl_lsm_secattr *secattr)
1809 {
1810 	int ret_val;
1811 	u32 iter;
1812 
1813 	if (buf_len <= CIPSO_V4_HDR_LEN)
1814 		return -ENOSPC;
1815 
1816 	/* XXX - This code assumes only one tag per CIPSO option which isn't
1817 	 * really a good assumption to make but since we only support the MAC
1818 	 * tags right now it is a safe assumption. */
1819 	iter = 0;
1820 	do {
1821 		memset(buf, 0, buf_len);
1822 		switch (doi_def->tags[iter]) {
1823 		case CIPSO_V4_TAG_RBITMAP:
1824 			ret_val = cipso_v4_gentag_rbm(doi_def,
1825 						   secattr,
1826 						   &buf[CIPSO_V4_HDR_LEN],
1827 						   buf_len - CIPSO_V4_HDR_LEN);
1828 			break;
1829 		case CIPSO_V4_TAG_ENUM:
1830 			ret_val = cipso_v4_gentag_enum(doi_def,
1831 						   secattr,
1832 						   &buf[CIPSO_V4_HDR_LEN],
1833 						   buf_len - CIPSO_V4_HDR_LEN);
1834 			break;
1835 		case CIPSO_V4_TAG_RANGE:
1836 			ret_val = cipso_v4_gentag_rng(doi_def,
1837 						   secattr,
1838 						   &buf[CIPSO_V4_HDR_LEN],
1839 						   buf_len - CIPSO_V4_HDR_LEN);
1840 			break;
1841 		case CIPSO_V4_TAG_LOCAL:
1842 			ret_val = cipso_v4_gentag_loc(doi_def,
1843 						   secattr,
1844 						   &buf[CIPSO_V4_HDR_LEN],
1845 						   buf_len - CIPSO_V4_HDR_LEN);
1846 			break;
1847 		default:
1848 			return -EPERM;
1849 		}
1850 
1851 		iter++;
1852 	} while (ret_val < 0 &&
1853 		 iter < CIPSO_V4_TAG_MAXCNT &&
1854 		 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
1855 	if (ret_val < 0)
1856 		return ret_val;
1857 	cipso_v4_gentag_hdr(doi_def, buf, ret_val);
1858 	return CIPSO_V4_HDR_LEN + ret_val;
1859 }
1860 
1861 /**
1862  * cipso_v4_sock_setattr - Add a CIPSO option to a socket
1863  * @sk: the socket
1864  * @doi_def: the CIPSO DOI to use
1865  * @secattr: the specific security attributes of the socket
1866  *
1867  * Description:
1868  * Set the CIPSO option on the given socket using the DOI definition and
1869  * security attributes passed to the function.  This function requires
1870  * exclusive access to @sk, which means it either needs to be in the
1871  * process of being created or locked.  Returns zero on success and negative
1872  * values on failure.
1873  *
1874  */
cipso_v4_sock_setattr(struct sock * sk,const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr)1875 int cipso_v4_sock_setattr(struct sock *sk,
1876 			  const struct cipso_v4_doi *doi_def,
1877 			  const struct netlbl_lsm_secattr *secattr)
1878 {
1879 	int ret_val = -EPERM;
1880 	unsigned char *buf = NULL;
1881 	u32 buf_len;
1882 	u32 opt_len;
1883 	struct ip_options *opt = NULL;
1884 	struct inet_sock *sk_inet;
1885 	struct inet_connection_sock *sk_conn;
1886 
1887 	/* In the case of sock_create_lite(), the sock->sk field is not
1888 	 * defined yet but it is not a problem as the only users of these
1889 	 * "lite" PF_INET sockets are functions which do an accept() call
1890 	 * afterwards so we will label the socket as part of the accept(). */
1891 	if (sk == NULL)
1892 		return 0;
1893 
1894 	/* We allocate the maximum CIPSO option size here so we are probably
1895 	 * being a little wasteful, but it makes our life _much_ easier later
1896 	 * on and after all we are only talking about 40 bytes. */
1897 	buf_len = CIPSO_V4_OPT_LEN_MAX;
1898 	buf = kmalloc(buf_len, GFP_ATOMIC);
1899 	if (buf == NULL) {
1900 		ret_val = -ENOMEM;
1901 		goto socket_setattr_failure;
1902 	}
1903 
1904 	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1905 	if (ret_val < 0)
1906 		goto socket_setattr_failure;
1907 	buf_len = ret_val;
1908 
1909 	/* We can't use ip_options_get() directly because it makes a call to
1910 	 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1911 	 * we won't always have CAP_NET_RAW even though we _always_ want to
1912 	 * set the IPOPT_CIPSO option. */
1913 	opt_len = (buf_len + 3) & ~3;
1914 	opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1915 	if (opt == NULL) {
1916 		ret_val = -ENOMEM;
1917 		goto socket_setattr_failure;
1918 	}
1919 	memcpy(opt->__data, buf, buf_len);
1920 	opt->optlen = opt_len;
1921 	opt->cipso = sizeof(struct iphdr);
1922 	kfree(buf);
1923 	buf = NULL;
1924 
1925 	sk_inet = inet_sk(sk);
1926 	if (sk_inet->is_icsk) {
1927 		sk_conn = inet_csk(sk);
1928 		if (sk_inet->opt)
1929 			sk_conn->icsk_ext_hdr_len -= sk_inet->opt->optlen;
1930 		sk_conn->icsk_ext_hdr_len += opt->optlen;
1931 		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
1932 	}
1933 	opt = xchg(&sk_inet->opt, opt);
1934 	kfree(opt);
1935 
1936 	return 0;
1937 
1938 socket_setattr_failure:
1939 	kfree(buf);
1940 	kfree(opt);
1941 	return ret_val;
1942 }
1943 
1944 /**
1945  * cipso_v4_sock_delattr - Delete the CIPSO option from a socket
1946  * @sk: the socket
1947  *
1948  * Description:
1949  * Removes the CIPSO option from a socket, if present.
1950  *
1951  */
cipso_v4_sock_delattr(struct sock * sk)1952 void cipso_v4_sock_delattr(struct sock *sk)
1953 {
1954 	u8 hdr_delta;
1955 	struct ip_options *opt;
1956 	struct inet_sock *sk_inet;
1957 
1958 	sk_inet = inet_sk(sk);
1959 	opt = sk_inet->opt;
1960 	if (opt == NULL || opt->cipso == 0)
1961 		return;
1962 
1963 	if (opt->srr || opt->rr || opt->ts || opt->router_alert) {
1964 		u8 cipso_len;
1965 		u8 cipso_off;
1966 		unsigned char *cipso_ptr;
1967 		int iter;
1968 		int optlen_new;
1969 
1970 		cipso_off = opt->cipso - sizeof(struct iphdr);
1971 		cipso_ptr = &opt->__data[cipso_off];
1972 		cipso_len = cipso_ptr[1];
1973 
1974 		if (opt->srr > opt->cipso)
1975 			opt->srr -= cipso_len;
1976 		if (opt->rr > opt->cipso)
1977 			opt->rr -= cipso_len;
1978 		if (opt->ts > opt->cipso)
1979 			opt->ts -= cipso_len;
1980 		if (opt->router_alert > opt->cipso)
1981 			opt->router_alert -= cipso_len;
1982 		opt->cipso = 0;
1983 
1984 		memmove(cipso_ptr, cipso_ptr + cipso_len,
1985 			opt->optlen - cipso_off - cipso_len);
1986 
1987 		/* determining the new total option length is tricky because of
1988 		 * the padding necessary, the only thing i can think to do at
1989 		 * this point is walk the options one-by-one, skipping the
1990 		 * padding at the end to determine the actual option size and
1991 		 * from there we can determine the new total option length */
1992 		iter = 0;
1993 		optlen_new = 0;
1994 		while (iter < opt->optlen)
1995 			if (opt->__data[iter] != IPOPT_NOP) {
1996 				iter += opt->__data[iter + 1];
1997 				optlen_new = iter;
1998 			} else
1999 				iter++;
2000 		hdr_delta = opt->optlen;
2001 		opt->optlen = (optlen_new + 3) & ~3;
2002 		hdr_delta -= opt->optlen;
2003 	} else {
2004 		/* only the cipso option was present on the socket so we can
2005 		 * remove the entire option struct */
2006 		sk_inet->opt = NULL;
2007 		hdr_delta = opt->optlen;
2008 		kfree(opt);
2009 	}
2010 
2011 	if (sk_inet->is_icsk && hdr_delta > 0) {
2012 		struct inet_connection_sock *sk_conn = inet_csk(sk);
2013 		sk_conn->icsk_ext_hdr_len -= hdr_delta;
2014 		sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
2015 	}
2016 }
2017 
2018 /**
2019  * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
2020  * @cipso: the CIPSO v4 option
2021  * @secattr: the security attributes
2022  *
2023  * Description:
2024  * Inspect @cipso and return the security attributes in @secattr.  Returns zero
2025  * on success and negative values on failure.
2026  *
2027  */
cipso_v4_getattr(const unsigned char * cipso,struct netlbl_lsm_secattr * secattr)2028 static int cipso_v4_getattr(const unsigned char *cipso,
2029 			    struct netlbl_lsm_secattr *secattr)
2030 {
2031 	int ret_val = -ENOMSG;
2032 	u32 doi;
2033 	struct cipso_v4_doi *doi_def;
2034 
2035 	if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0)
2036 		return 0;
2037 
2038 	doi = get_unaligned_be32(&cipso[2]);
2039 	rcu_read_lock();
2040 	doi_def = cipso_v4_doi_search(doi);
2041 	if (doi_def == NULL)
2042 		goto getattr_return;
2043 	/* XXX - This code assumes only one tag per CIPSO option which isn't
2044 	 * really a good assumption to make but since we only support the MAC
2045 	 * tags right now it is a safe assumption. */
2046 	switch (cipso[6]) {
2047 	case CIPSO_V4_TAG_RBITMAP:
2048 		ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr);
2049 		break;
2050 	case CIPSO_V4_TAG_ENUM:
2051 		ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr);
2052 		break;
2053 	case CIPSO_V4_TAG_RANGE:
2054 		ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr);
2055 		break;
2056 	case CIPSO_V4_TAG_LOCAL:
2057 		ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr);
2058 		break;
2059 	}
2060 	if (ret_val == 0)
2061 		secattr->type = NETLBL_NLTYPE_CIPSOV4;
2062 
2063 getattr_return:
2064 	rcu_read_unlock();
2065 	return ret_val;
2066 }
2067 
2068 /**
2069  * cipso_v4_sock_getattr - Get the security attributes from a sock
2070  * @sk: the sock
2071  * @secattr: the security attributes
2072  *
2073  * Description:
2074  * Query @sk to see if there is a CIPSO option attached to the sock and if
2075  * there is return the CIPSO security attributes in @secattr.  This function
2076  * requires that @sk be locked, or privately held, but it does not do any
2077  * locking itself.  Returns zero on success and negative values on failure.
2078  *
2079  */
cipso_v4_sock_getattr(struct sock * sk,struct netlbl_lsm_secattr * secattr)2080 int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
2081 {
2082 	struct ip_options *opt;
2083 
2084 	opt = inet_sk(sk)->opt;
2085 	if (opt == NULL || opt->cipso == 0)
2086 		return -ENOMSG;
2087 
2088 	return cipso_v4_getattr(opt->__data + opt->cipso - sizeof(struct iphdr),
2089 				secattr);
2090 }
2091 
2092 /**
2093  * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
2094  * @skb: the packet
2095  * @secattr: the security attributes
2096  *
2097  * Description:
2098  * Set the CIPSO option on the given packet based on the security attributes.
2099  * Returns a pointer to the IP header on success and NULL on failure.
2100  *
2101  */
cipso_v4_skbuff_setattr(struct sk_buff * skb,const struct cipso_v4_doi * doi_def,const struct netlbl_lsm_secattr * secattr)2102 int cipso_v4_skbuff_setattr(struct sk_buff *skb,
2103 			    const struct cipso_v4_doi *doi_def,
2104 			    const struct netlbl_lsm_secattr *secattr)
2105 {
2106 	int ret_val;
2107 	struct iphdr *iph;
2108 	struct ip_options *opt = &IPCB(skb)->opt;
2109 	unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
2110 	u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
2111 	u32 opt_len;
2112 	int len_delta;
2113 
2114 	ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
2115 	if (ret_val < 0)
2116 		return ret_val;
2117 	buf_len = ret_val;
2118 	opt_len = (buf_len + 3) & ~3;
2119 
2120 	/* we overwrite any existing options to ensure that we have enough
2121 	 * room for the CIPSO option, the reason is that we _need_ to guarantee
2122 	 * that the security label is applied to the packet - we do the same
2123 	 * thing when using the socket options and it hasn't caused a problem,
2124 	 * if we need to we can always revisit this choice later */
2125 
2126 	len_delta = opt_len - opt->optlen;
2127 	/* if we don't ensure enough headroom we could panic on the skb_push()
2128 	 * call below so make sure we have enough, we are also "mangling" the
2129 	 * packet so we should probably do a copy-on-write call anyway */
2130 	ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
2131 	if (ret_val < 0)
2132 		return ret_val;
2133 
2134 	if (len_delta > 0) {
2135 		/* we assume that the header + opt->optlen have already been
2136 		 * "pushed" in ip_options_build() or similar */
2137 		iph = ip_hdr(skb);
2138 		skb_push(skb, len_delta);
2139 		memmove((char *)iph - len_delta, iph, iph->ihl << 2);
2140 		skb_reset_network_header(skb);
2141 		iph = ip_hdr(skb);
2142 	} else if (len_delta < 0) {
2143 		iph = ip_hdr(skb);
2144 		memset(iph + 1, IPOPT_NOP, opt->optlen);
2145 	} else
2146 		iph = ip_hdr(skb);
2147 
2148 	if (opt->optlen > 0)
2149 		memset(opt, 0, sizeof(*opt));
2150 	opt->optlen = opt_len;
2151 	opt->cipso = sizeof(struct iphdr);
2152 	opt->is_changed = 1;
2153 
2154 	/* we have to do the following because we are being called from a
2155 	 * netfilter hook which means the packet already has had the header
2156 	 * fields populated and the checksum calculated - yes this means we
2157 	 * are doing more work than needed but we do it to keep the core
2158 	 * stack clean and tidy */
2159 	memcpy(iph + 1, buf, buf_len);
2160 	if (opt_len > buf_len)
2161 		memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
2162 	if (len_delta != 0) {
2163 		iph->ihl = 5 + (opt_len >> 2);
2164 		iph->tot_len = htons(skb->len);
2165 	}
2166 	ip_send_check(iph);
2167 
2168 	return 0;
2169 }
2170 
2171 /**
2172  * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
2173  * @skb: the packet
2174  *
2175  * Description:
2176  * Removes any and all CIPSO options from the given packet.  Returns zero on
2177  * success, negative values on failure.
2178  *
2179  */
cipso_v4_skbuff_delattr(struct sk_buff * skb)2180 int cipso_v4_skbuff_delattr(struct sk_buff *skb)
2181 {
2182 	int ret_val;
2183 	struct iphdr *iph;
2184 	struct ip_options *opt = &IPCB(skb)->opt;
2185 	unsigned char *cipso_ptr;
2186 
2187 	if (opt->cipso == 0)
2188 		return 0;
2189 
2190 	/* since we are changing the packet we should make a copy */
2191 	ret_val = skb_cow(skb, skb_headroom(skb));
2192 	if (ret_val < 0)
2193 		return ret_val;
2194 
2195 	/* the easiest thing to do is just replace the cipso option with noop
2196 	 * options since we don't change the size of the packet, although we
2197 	 * still need to recalculate the checksum */
2198 
2199 	iph = ip_hdr(skb);
2200 	cipso_ptr = (unsigned char *)iph + opt->cipso;
2201 	memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]);
2202 	opt->cipso = 0;
2203 	opt->is_changed = 1;
2204 
2205 	ip_send_check(iph);
2206 
2207 	return 0;
2208 }
2209 
2210 /**
2211  * cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option
2212  * @skb: the packet
2213  * @secattr: the security attributes
2214  *
2215  * Description:
2216  * Parse the given packet's CIPSO option and return the security attributes.
2217  * Returns zero on success and negative values on failure.
2218  *
2219  */
cipso_v4_skbuff_getattr(const struct sk_buff * skb,struct netlbl_lsm_secattr * secattr)2220 int cipso_v4_skbuff_getattr(const struct sk_buff *skb,
2221 			    struct netlbl_lsm_secattr *secattr)
2222 {
2223 	return cipso_v4_getattr(CIPSO_V4_OPTPTR(skb), secattr);
2224 }
2225 
2226 /*
2227  * Setup Functions
2228  */
2229 
2230 /**
2231  * cipso_v4_init - Initialize the CIPSO module
2232  *
2233  * Description:
2234  * Initialize the CIPSO module and prepare it for use.  Returns zero on success
2235  * and negative values on failure.
2236  *
2237  */
cipso_v4_init(void)2238 static int __init cipso_v4_init(void)
2239 {
2240 	int ret_val;
2241 
2242 	ret_val = cipso_v4_cache_init();
2243 	if (ret_val != 0)
2244 		panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
2245 		      ret_val);
2246 
2247 	return 0;
2248 }
2249 
2250 subsys_initcall(cipso_v4_init);
2251