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