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://tools.ietf.org/id/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, see <http://www.gnu.org/licenses/>.
35 *
36 */
37
38#include <linux/init.h>
39#include <linux/types.h>
40#include <linux/rcupdate.h>
41#include <linux/list.h>
42#include <linux/spinlock.h>
43#include <linux/string.h>
44#include <linux/jhash.h>
45#include <linux/audit.h>
46#include <linux/slab.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 <linux/atomic.h>
53#include <linux/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. */
61static DEFINE_SPINLOCK(cipso_v4_doi_list_lock);
62static LIST_HEAD(cipso_v4_doi_list);
63
64/* Label mapping cache */
65int cipso_v4_cache_enabled = 1;
66int 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
70struct cipso_v4_map_cache_bkt {
71 spinlock_t lock;
72 u32 size;
73 struct list_head list;
74};
75
76struct cipso_v4_map_cache_entry {
77 u32 hash;
78 unsigned char *key;
79 size_t key_len;
80
81 struct netlbl_lsm_cache *lsm_data;
82
83 u32 activity;
84 struct list_head list;
85};
86
87static struct cipso_v4_map_cache_bkt *cipso_v4_cache;
88
89/* Restricted bitmap (tag #1) flags */
90int cipso_v4_rbm_optfmt = 0;
91int cipso_v4_rbm_strictvalid = 1;
92
93/*
94 * Protocol Constants
95 */
96
97/* Maximum size of the CIPSO IP option, derived from the fact that the maximum
98 * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */
99#define CIPSO_V4_OPT_LEN_MAX 40
100
101/* Length of the base CIPSO option, this includes the option type (1 byte), the
102 * option length (1 byte), and the DOI (4 bytes). */
103#define CIPSO_V4_HDR_LEN 6
104
105/* Base length of the restrictive category bitmap tag (tag #1). */
106#define CIPSO_V4_TAG_RBM_BLEN 4
107
108/* Base length of the enumerated category tag (tag #2). */
109#define CIPSO_V4_TAG_ENUM_BLEN 4
110
111/* Base length of the ranged categories bitmap tag (tag #5). */
112#define CIPSO_V4_TAG_RNG_BLEN 4
113/* The maximum number of category ranges permitted in the ranged category tag
114 * (tag #5). You may note that the IETF draft states that the maximum number
115 * of category ranges is 7, but if the low end of the last category range is
116 * zero then it is possible to fit 8 category ranges because the zero should
117 * be omitted. */
118#define CIPSO_V4_TAG_RNG_CAT_MAX 8
119
120/* Base length of the local tag (non-standard tag).
121 * Tag definition (may change between kernel versions)
122 *
123 * 0 8 16 24 32
124 * +----------+----------+----------+----------+
125 * | 10000000 | 00000110 | 32-bit secid value |
126 * +----------+----------+----------+----------+
127 * | in (host byte order)|
128 * +----------+----------+
129 *
130 */
131#define CIPSO_V4_TAG_LOC_BLEN 6
132
133/*
134 * Helper Functions
135 */
136
137/**
138 * cipso_v4_cache_entry_free - Frees a cache entry
139 * @entry: the entry to free
140 *
141 * Description:
142 * This function frees the memory associated with a cache entry including the
143 * LSM cache data if there are no longer any users, i.e. reference count == 0.
144 *
145 */
146static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry)
147{
148 if (entry->lsm_data)
149 netlbl_secattr_cache_free(entry->lsm_data);
150 kfree(entry->key);
151 kfree(entry);
152}
153
154/**
155 * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache
156 * @key: the hash key
157 * @key_len: the length of the key in bytes
158 *
159 * Description:
160 * The CIPSO tag hashing function. Returns a 32-bit hash value.
161 *
162 */
163static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len)
164{
165 return jhash(key, key_len, 0);
166}
167
168/*
169 * Label Mapping Cache Functions
170 */
171
172/**
173 * cipso_v4_cache_init - Initialize the CIPSO cache
174 *
175 * Description:
176 * Initializes the CIPSO label mapping cache, this function should be called
177 * before any of the other functions defined in this file. Returns zero on
178 * success, negative values on error.
179 *
180 */
181static int __init cipso_v4_cache_init(void)
182{
183 u32 iter;
184
185 cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS,
186 sizeof(struct cipso_v4_map_cache_bkt),
187 GFP_KERNEL);
188 if (!cipso_v4_cache)
189 return -ENOMEM;
190
191 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
192 spin_lock_init(&cipso_v4_cache[iter].lock);
193 cipso_v4_cache[iter].size = 0;
194 INIT_LIST_HEAD(&cipso_v4_cache[iter].list);
195 }
196
197 return 0;
198}
199
200/**
201 * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache
202 *
203 * Description:
204 * Invalidates and frees any entries in the CIPSO cache. Returns zero on
205 * success and negative values on failure.
206 *
207 */
208void cipso_v4_cache_invalidate(void)
209{
210 struct cipso_v4_map_cache_entry *entry, *tmp_entry;
211 u32 iter;
212
213 for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
214 spin_lock_bh(&cipso_v4_cache[iter].lock);
215 list_for_each_entry_safe(entry,
216 tmp_entry,
217 &cipso_v4_cache[iter].list, list) {
218 list_del(&entry->list);
219 cipso_v4_cache_entry_free(entry);
220 }
221 cipso_v4_cache[iter].size = 0;
222 spin_unlock_bh(&cipso_v4_cache[iter].lock);
223 }
224}
225
226/**
227 * cipso_v4_cache_check - Check the CIPSO cache for a label mapping
228 * @key: the buffer to check
229 * @key_len: buffer length in bytes
230 * @secattr: the security attribute struct to use
231 *
232 * Description:
233 * This function checks the cache to see if a label mapping already exists for
234 * the given key. If there is a match then the cache is adjusted and the
235 * @secattr struct is populated with the correct LSM security attributes. The
236 * cache is adjusted in the following manner if the entry is not already the
237 * first in the cache bucket:
238 *
239 * 1. The cache entry's activity counter is incremented
240 * 2. The previous (higher ranking) entry's activity counter is decremented
241 * 3. If the difference between the two activity counters is geater than
242 * CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped
243 *
244 * Returns zero on success, -ENOENT for a cache miss, and other negative values
245 * on error.
246 *
247 */
248static int cipso_v4_cache_check(const unsigned char *key,
249 u32 key_len,
250 struct netlbl_lsm_secattr *secattr)
251{
252 u32 bkt;
253 struct cipso_v4_map_cache_entry *entry;
254 struct cipso_v4_map_cache_entry *prev_entry = NULL;
255 u32 hash;
256
257 if (!cipso_v4_cache_enabled)
258 return -ENOENT;
259
260 hash = cipso_v4_map_cache_hash(key, key_len);
261 bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
262 spin_lock_bh(&cipso_v4_cache[bkt].lock);
263 list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
264 if (entry->hash == hash &&
265 entry->key_len == key_len &&
266 memcmp(entry->key, key, key_len) == 0) {
267 entry->activity += 1;
268 refcount_inc(&entry->lsm_data->refcount);
269 secattr->cache = entry->lsm_data;
270 secattr->flags |= NETLBL_SECATTR_CACHE;
271 secattr->type = NETLBL_NLTYPE_CIPSOV4;
272 if (!prev_entry) {
273 spin_unlock_bh(&cipso_v4_cache[bkt].lock);
274 return 0;
275 }
276
277 if (prev_entry->activity > 0)
278 prev_entry->activity -= 1;
279 if (entry->activity > prev_entry->activity &&
280 entry->activity - prev_entry->activity >
281 CIPSO_V4_CACHE_REORDERLIMIT) {
282 __list_del(entry->list.prev, entry->list.next);
283 __list_add(&entry->list,
284 prev_entry->list.prev,
285 &prev_entry->list);
286 }
287
288 spin_unlock_bh(&cipso_v4_cache[bkt].lock);
289 return 0;
290 }
291 prev_entry = entry;
292 }
293 spin_unlock_bh(&cipso_v4_cache[bkt].lock);
294
295 return -ENOENT;
296}
297
298/**
299 * cipso_v4_cache_add - Add an entry to the CIPSO cache
300 * @skb: the packet
301 * @secattr: the packet's security attributes
302 *
303 * Description:
304 * Add a new entry into the CIPSO label mapping cache. Add the new entry to
305 * head of the cache bucket's list, if the cache bucket is out of room remove
306 * the last entry in the list first. It is important to note that there is
307 * currently no checking for duplicate keys. Returns zero on success,
308 * negative values on failure.
309 *
310 */
311int cipso_v4_cache_add(const unsigned char *cipso_ptr,
312 const struct netlbl_lsm_secattr *secattr)
313{
314 int ret_val = -EPERM;
315 u32 bkt;
316 struct cipso_v4_map_cache_entry *entry = NULL;
317 struct cipso_v4_map_cache_entry *old_entry = NULL;
318 u32 cipso_ptr_len;
319
320 if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0)
321 return 0;
322
323 cipso_ptr_len = cipso_ptr[1];
324
325 entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
326 if (!entry)
327 return -ENOMEM;
328 entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC);
329 if (!entry->key) {
330 ret_val = -ENOMEM;
331 goto cache_add_failure;
332 }
333 entry->key_len = cipso_ptr_len;
334 entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len);
335 refcount_inc(&secattr->cache->refcount);
336 entry->lsm_data = secattr->cache;
337
338 bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1);
339 spin_lock_bh(&cipso_v4_cache[bkt].lock);
340 if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) {
341 list_add(&entry->list, &cipso_v4_cache[bkt].list);
342 cipso_v4_cache[bkt].size += 1;
343 } else {
344 old_entry = list_entry(cipso_v4_cache[bkt].list.prev,
345 struct cipso_v4_map_cache_entry, list);
346 list_del(&old_entry->list);
347 list_add(&entry->list, &cipso_v4_cache[bkt].list);
348 cipso_v4_cache_entry_free(old_entry);
349 }
350 spin_unlock_bh(&cipso_v4_cache[bkt].lock);
351
352 return 0;
353
354cache_add_failure:
355 if (entry)
356 cipso_v4_cache_entry_free(entry);
357 return ret_val;
358}
359
360/*
361 * DOI List Functions
362 */
363
364/**
365 * cipso_v4_doi_search - Searches for a DOI definition
366 * @doi: the DOI to search for
367 *
368 * Description:
369 * Search the DOI definition list for a DOI definition with a DOI value that
370 * matches @doi. The caller is responsible for calling rcu_read_[un]lock().
371 * Returns a pointer to the DOI definition on success and NULL on failure.
372 */
373static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi)
374{
375 struct cipso_v4_doi *iter;
376
377 list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list)
378 if (iter->doi == doi && refcount_read(&iter->refcount))
379 return iter;
380 return NULL;
381}
382
383/**
384 * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine
385 * @doi_def: the DOI structure
386 * @audit_info: NetLabel audit information
387 *
388 * Description:
389 * The caller defines a new DOI for use by the CIPSO engine and calls this
390 * function to add it to the list of acceptable domains. The caller must
391 * ensure that the mapping table specified in @doi_def->map meets all of the
392 * requirements of the mapping type (see cipso_ipv4.h for details). Returns
393 * zero on success and non-zero on failure.
394 *
395 */
396int cipso_v4_doi_add(struct cipso_v4_doi *doi_def,
397 struct netlbl_audit *audit_info)
398{
399 int ret_val = -EINVAL;
400 u32 iter;
401 u32 doi;
402 u32 doi_type;
403 struct audit_buffer *audit_buf;
404
405 doi = doi_def->doi;
406 doi_type = doi_def->type;
407
408 if (doi_def->doi == CIPSO_V4_DOI_UNKNOWN)
409 goto doi_add_return;
410 for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) {
411 switch (doi_def->tags[iter]) {
412 case CIPSO_V4_TAG_RBITMAP:
413 break;
414 case CIPSO_V4_TAG_RANGE:
415 case CIPSO_V4_TAG_ENUM:
416 if (doi_def->type != CIPSO_V4_MAP_PASS)
417 goto doi_add_return;
418 break;
419 case CIPSO_V4_TAG_LOCAL:
420 if (doi_def->type != CIPSO_V4_MAP_LOCAL)
421 goto doi_add_return;
422 break;
423 case CIPSO_V4_TAG_INVALID:
424 if (iter == 0)
425 goto doi_add_return;
426 break;
427 default:
428 goto doi_add_return;
429 }
430 }
431
432 refcount_set(&doi_def->refcount, 1);
433
434 spin_lock(&cipso_v4_doi_list_lock);
435 if (cipso_v4_doi_search(doi_def->doi)) {
436 spin_unlock(&cipso_v4_doi_list_lock);
437 ret_val = -EEXIST;
438 goto doi_add_return;
439 }
440 list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list);
441 spin_unlock(&cipso_v4_doi_list_lock);
442 ret_val = 0;
443
444doi_add_return:
445 audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info);
446 if (audit_buf) {
447 const char *type_str;
448 switch (doi_type) {
449 case CIPSO_V4_MAP_TRANS:
450 type_str = "trans";
451 break;
452 case CIPSO_V4_MAP_PASS:
453 type_str = "pass";
454 break;
455 case CIPSO_V4_MAP_LOCAL:
456 type_str = "local";
457 break;
458 default:
459 type_str = "(unknown)";
460 }
461 audit_log_format(audit_buf,
462 " cipso_doi=%u cipso_type=%s res=%u",
463 doi, type_str, ret_val == 0 ? 1 : 0);
464 audit_log_end(audit_buf);
465 }
466
467 return ret_val;
468}
469
470/**
471 * cipso_v4_doi_free - Frees a DOI definition
472 * @doi_def: the DOI definition
473 *
474 * Description:
475 * This function frees all of the memory associated with a DOI definition.
476 *
477 */
478void cipso_v4_doi_free(struct cipso_v4_doi *doi_def)
479{
480 if (!doi_def)
481 return;
482
483 switch (doi_def->type) {
484 case CIPSO_V4_MAP_TRANS:
485 kfree(doi_def->map.std->lvl.cipso);
486 kfree(doi_def->map.std->lvl.local);
487 kfree(doi_def->map.std->cat.cipso);
488 kfree(doi_def->map.std->cat.local);
489 break;
490 }
491 kfree(doi_def);
492}
493
494/**
495 * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer
496 * @entry: the entry's RCU field
497 *
498 * Description:
499 * This function is designed to be used as a callback to the call_rcu()
500 * function so that the memory allocated to the DOI definition can be released
501 * safely.
502 *
503 */
504static void cipso_v4_doi_free_rcu(struct rcu_head *entry)
505{
506 struct cipso_v4_doi *doi_def;
507
508 doi_def = container_of(entry, struct cipso_v4_doi, rcu);
509 cipso_v4_doi_free(doi_def);
510}
511
512/**
513 * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine
514 * @doi: the DOI value
515 * @audit_secid: the LSM secid to use in the audit message
516 *
517 * Description:
518 * Removes a DOI definition from the CIPSO engine. The NetLabel routines will
519 * be called to release their own LSM domain mappings as well as our own
520 * domain list. Returns zero on success and negative values on failure.
521 *
522 */
523int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info)
524{
525 int ret_val;
526 struct cipso_v4_doi *doi_def;
527 struct audit_buffer *audit_buf;
528
529 spin_lock(&cipso_v4_doi_list_lock);
530 doi_def = cipso_v4_doi_search(doi);
531 if (!doi_def) {
532 spin_unlock(&cipso_v4_doi_list_lock);
533 ret_val = -ENOENT;
534 goto doi_remove_return;
535 }
536 if (!refcount_dec_and_test(&doi_def->refcount)) {
537 spin_unlock(&cipso_v4_doi_list_lock);
538 ret_val = -EBUSY;
539 goto doi_remove_return;
540 }
541 list_del_rcu(&doi_def->list);
542 spin_unlock(&cipso_v4_doi_list_lock);
543
544 cipso_v4_cache_invalidate();
545 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
546 ret_val = 0;
547
548doi_remove_return:
549 audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info);
550 if (audit_buf) {
551 audit_log_format(audit_buf,
552 " cipso_doi=%u res=%u",
553 doi, ret_val == 0 ? 1 : 0);
554 audit_log_end(audit_buf);
555 }
556
557 return ret_val;
558}
559
560/**
561 * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition
562 * @doi: the DOI value
563 *
564 * Description:
565 * Searches for a valid DOI definition and if one is found it is returned to
566 * the caller. Otherwise NULL is returned. The caller must ensure that
567 * rcu_read_lock() is held while accessing the returned definition and the DOI
568 * definition reference count is decremented when the caller is done.
569 *
570 */
571struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
572{
573 struct cipso_v4_doi *doi_def;
574
575 rcu_read_lock();
576 doi_def = cipso_v4_doi_search(doi);
577 if (!doi_def)
578 goto doi_getdef_return;
579 if (!refcount_inc_not_zero(&doi_def->refcount))
580 doi_def = NULL;
581
582doi_getdef_return:
583 rcu_read_unlock();
584 return doi_def;
585}
586
587/**
588 * cipso_v4_doi_putdef - Releases a reference for the given DOI definition
589 * @doi_def: the DOI definition
590 *
591 * Description:
592 * Releases a DOI definition reference obtained from cipso_v4_doi_getdef().
593 *
594 */
595void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def)
596{
597 if (!doi_def)
598 return;
599
600 if (!refcount_dec_and_test(&doi_def->refcount))
601 return;
602 spin_lock(&cipso_v4_doi_list_lock);
603 list_del_rcu(&doi_def->list);
604 spin_unlock(&cipso_v4_doi_list_lock);
605
606 cipso_v4_cache_invalidate();
607 call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
608}
609
610/**
611 * cipso_v4_doi_walk - Iterate through the DOI definitions
612 * @skip_cnt: skip past this number of DOI definitions, updated
613 * @callback: callback for each DOI definition
614 * @cb_arg: argument for the callback function
615 *
616 * Description:
617 * Iterate over the DOI definition list, skipping the first @skip_cnt entries.
618 * For each entry call @callback, if @callback returns a negative value stop
619 * 'walking' through the list and return. Updates the value in @skip_cnt upon
620 * return. Returns zero on success, negative values on failure.
621 *
622 */
623int cipso_v4_doi_walk(u32 *skip_cnt,
624 int (*callback) (struct cipso_v4_doi *doi_def, void *arg),
625 void *cb_arg)
626{
627 int ret_val = -ENOENT;
628 u32 doi_cnt = 0;
629 struct cipso_v4_doi *iter_doi;
630
631 rcu_read_lock();
632 list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
633 if (refcount_read(&iter_doi->refcount) > 0) {
634 if (doi_cnt++ < *skip_cnt)
635 continue;
636 ret_val = callback(iter_doi, cb_arg);
637 if (ret_val < 0) {
638 doi_cnt--;
639 goto doi_walk_return;
640 }
641 }
642
643doi_walk_return:
644 rcu_read_unlock();
645 *skip_cnt = doi_cnt;
646 return ret_val;
647}
648
649/*
650 * Label Mapping Functions
651 */
652
653/**
654 * cipso_v4_map_lvl_valid - Checks to see if the given level is understood
655 * @doi_def: the DOI definition
656 * @level: the level to check
657 *
658 * Description:
659 * Checks the given level against the given DOI definition and returns a
660 * negative value if the level does not have a valid mapping and a zero value
661 * if the level is defined by the DOI.
662 *
663 */
664static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
665{
666 switch (doi_def->type) {
667 case CIPSO_V4_MAP_PASS:
668 return 0;
669 case CIPSO_V4_MAP_TRANS:
670 if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL)
671 return 0;
672 break;
673 }
674
675 return -EFAULT;
676}
677
678/**
679 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
680 * @doi_def: the DOI definition
681 * @host_lvl: the host MLS level
682 * @net_lvl: the network/CIPSO MLS level
683 *
684 * Description:
685 * Perform a label mapping to translate a local MLS level to the correct
686 * CIPSO level using the given DOI definition. Returns zero on success,
687 * negative values otherwise.
688 *
689 */
690static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
691 u32 host_lvl,
692 u32 *net_lvl)
693{
694 switch (doi_def->type) {
695 case CIPSO_V4_MAP_PASS:
696 *net_lvl = host_lvl;
697 return 0;
698 case CIPSO_V4_MAP_TRANS:
699 if (host_lvl < doi_def->map.std->lvl.local_size &&
700 doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) {
701 *net_lvl = doi_def->map.std->lvl.local[host_lvl];
702 return 0;
703 }
704 return -EPERM;
705 }
706
707 return -EINVAL;
708}
709
710/**
711 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
712 * @doi_def: the DOI definition
713 * @net_lvl: the network/CIPSO MLS level
714 * @host_lvl: the host MLS level
715 *
716 * Description:
717 * Perform a label mapping to translate a CIPSO level to the correct local MLS
718 * level using the given DOI definition. Returns zero on success, negative
719 * values otherwise.
720 *
721 */
722static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
723 u32 net_lvl,
724 u32 *host_lvl)
725{
726 struct cipso_v4_std_map_tbl *map_tbl;
727
728 switch (doi_def->type) {
729 case CIPSO_V4_MAP_PASS:
730 *host_lvl = net_lvl;
731 return 0;
732 case CIPSO_V4_MAP_TRANS:
733 map_tbl = doi_def->map.std;
734 if (net_lvl < map_tbl->lvl.cipso_size &&
735 map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
736 *host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
737 return 0;
738 }
739 return -EPERM;
740 }
741
742 return -EINVAL;
743}
744
745/**
746 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
747 * @doi_def: the DOI definition
748 * @bitmap: category bitmap
749 * @bitmap_len: bitmap length in bytes
750 *
751 * Description:
752 * Checks the given category bitmap against the given DOI definition and
753 * returns a negative value if any of the categories in the bitmap do not have
754 * a valid mapping and a zero value if all of the categories are valid.
755 *
756 */
757static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
758 const unsigned char *bitmap,
759 u32 bitmap_len)
760{
761 int cat = -1;
762 u32 bitmap_len_bits = bitmap_len * 8;
763 u32 cipso_cat_size;
764 u32 *cipso_array;
765
766 switch (doi_def->type) {
767 case CIPSO_V4_MAP_PASS:
768 return 0;
769 case CIPSO_V4_MAP_TRANS:
770 cipso_cat_size = doi_def->map.std->cat.cipso_size;
771 cipso_array = doi_def->map.std->cat.cipso;
772 for (;;) {
773 cat = netlbl_bitmap_walk(bitmap,
774 bitmap_len_bits,
775 cat + 1,
776 1);
777 if (cat < 0)
778 break;
779 if (cat >= cipso_cat_size ||
780 cipso_array[cat] >= CIPSO_V4_INV_CAT)
781 return -EFAULT;
782 }
783
784 if (cat == -1)
785 return 0;
786 break;
787 }
788
789 return -EFAULT;
790}
791
792/**
793 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
794 * @doi_def: the DOI definition
795 * @secattr: the security attributes
796 * @net_cat: the zero'd out category bitmap in network/CIPSO format
797 * @net_cat_len: the length of the CIPSO bitmap in bytes
798 *
799 * Description:
800 * Perform a label mapping to translate a local MLS category bitmap to the
801 * correct CIPSO bitmap using the given DOI definition. Returns the minimum
802 * size in bytes of the network bitmap on success, negative values otherwise.
803 *
804 */
805static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
806 const struct netlbl_lsm_secattr *secattr,
807 unsigned char *net_cat,
808 u32 net_cat_len)
809{
810 int host_spot = -1;
811 u32 net_spot = CIPSO_V4_INV_CAT;
812 u32 net_spot_max = 0;
813 u32 net_clen_bits = net_cat_len * 8;
814 u32 host_cat_size = 0;
815 u32 *host_cat_array = NULL;
816
817 if (doi_def->type == CIPSO_V4_MAP_TRANS) {
818 host_cat_size = doi_def->map.std->cat.local_size;
819 host_cat_array = doi_def->map.std->cat.local;
820 }
821
822 for (;;) {
823 host_spot = netlbl_catmap_walk(secattr->attr.mls.cat,
824 host_spot + 1);
825 if (host_spot < 0)
826 break;
827
828 switch (doi_def->type) {
829 case CIPSO_V4_MAP_PASS:
830 net_spot = host_spot;
831 break;
832 case CIPSO_V4_MAP_TRANS:
833 if (host_spot >= host_cat_size)
834 return -EPERM;
835 net_spot = host_cat_array[host_spot];
836 if (net_spot >= CIPSO_V4_INV_CAT)
837 return -EPERM;
838 break;
839 }
840 if (net_spot >= net_clen_bits)
841 return -ENOSPC;
842 netlbl_bitmap_setbit(net_cat, net_spot, 1);
843
844 if (net_spot > net_spot_max)
845 net_spot_max = net_spot;
846 }
847
848 if (++net_spot_max % 8)
849 return net_spot_max / 8 + 1;
850 return net_spot_max / 8;
851}
852
853/**
854 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host
855 * @doi_def: the DOI definition
856 * @net_cat: the category bitmap in network/CIPSO format
857 * @net_cat_len: the length of the CIPSO bitmap in bytes
858 * @secattr: the security attributes
859 *
860 * Description:
861 * Perform a label mapping to translate a CIPSO bitmap to the correct local
862 * MLS category bitmap using the given DOI definition. Returns zero on
863 * success, negative values on failure.
864 *
865 */
866static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
867 const unsigned char *net_cat,
868 u32 net_cat_len,
869 struct netlbl_lsm_secattr *secattr)
870{
871 int ret_val;
872 int net_spot = -1;
873 u32 host_spot = CIPSO_V4_INV_CAT;
874 u32 net_clen_bits = net_cat_len * 8;
875 u32 net_cat_size = 0;
876 u32 *net_cat_array = NULL;
877
878 if (doi_def->type == CIPSO_V4_MAP_TRANS) {
879 net_cat_size = doi_def->map.std->cat.cipso_size;
880 net_cat_array = doi_def->map.std->cat.cipso;
881 }
882
883 for (;;) {
884 net_spot = netlbl_bitmap_walk(net_cat,
885 net_clen_bits,
886 net_spot + 1,
887 1);
888 if (net_spot < 0) {
889 if (net_spot == -2)
890 return -EFAULT;
891 return 0;
892 }
893
894 switch (doi_def->type) {
895 case CIPSO_V4_MAP_PASS:
896 host_spot = net_spot;
897 break;
898 case CIPSO_V4_MAP_TRANS:
899 if (net_spot >= net_cat_size)
900 return -EPERM;
901 host_spot = net_cat_array[net_spot];
902 if (host_spot >= CIPSO_V4_INV_CAT)
903 return -EPERM;
904 break;
905 }
906 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
907 host_spot,
908 GFP_ATOMIC);
909 if (ret_val != 0)
910 return ret_val;
911 }
912
913 return -EINVAL;
914}
915
916/**
917 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid
918 * @doi_def: the DOI definition
919 * @enumcat: category list
920 * @enumcat_len: length of the category list in bytes
921 *
922 * Description:
923 * Checks the given categories against the given DOI definition and returns a
924 * negative value if any of the categories do not have a valid mapping and a
925 * zero value if all of the categories are valid.
926 *
927 */
928static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def,
929 const unsigned char *enumcat,
930 u32 enumcat_len)
931{
932 u16 cat;
933 int cat_prev = -1;
934 u32 iter;
935
936 if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01)
937 return -EFAULT;
938
939 for (iter = 0; iter < enumcat_len; iter += 2) {
940 cat = get_unaligned_be16(&enumcat[iter]);
941 if (cat <= cat_prev)
942 return -EFAULT;
943 cat_prev = cat;
944 }
945
946 return 0;
947}
948
949/**
950 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network
951 * @doi_def: the DOI definition
952 * @secattr: the security attributes
953 * @net_cat: the zero'd out category list in network/CIPSO format
954 * @net_cat_len: the length of the CIPSO category list in bytes
955 *
956 * Description:
957 * Perform a label mapping to translate a local MLS category bitmap to the
958 * correct CIPSO category list using the given DOI definition. Returns the
959 * size in bytes of the network category bitmap on success, negative values
960 * otherwise.
961 *
962 */
963static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def,
964 const struct netlbl_lsm_secattr *secattr,
965 unsigned char *net_cat,
966 u32 net_cat_len)
967{
968 int cat = -1;
969 u32 cat_iter = 0;
970
971 for (;;) {
972 cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1);
973 if (cat < 0)
974 break;
975 if ((cat_iter + 2) > net_cat_len)
976 return -ENOSPC;
977
978 *((__be16 *)&net_cat[cat_iter]) = htons(cat);
979 cat_iter += 2;
980 }
981
982 return cat_iter;
983}
984
985/**
986 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host
987 * @doi_def: the DOI definition
988 * @net_cat: the category list in network/CIPSO format
989 * @net_cat_len: the length of the CIPSO bitmap in bytes
990 * @secattr: the security attributes
991 *
992 * Description:
993 * Perform a label mapping to translate a CIPSO category list to the correct
994 * local MLS category bitmap using the given DOI definition. Returns zero on
995 * success, negative values on failure.
996 *
997 */
998static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def,
999 const unsigned char *net_cat,
1000 u32 net_cat_len,
1001 struct netlbl_lsm_secattr *secattr)
1002{
1003 int ret_val;
1004 u32 iter;
1005
1006 for (iter = 0; iter < net_cat_len; iter += 2) {
1007 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
1008 get_unaligned_be16(&net_cat[iter]),
1009 GFP_ATOMIC);
1010 if (ret_val != 0)
1011 return ret_val;
1012 }
1013
1014 return 0;
1015}
1016
1017/**
1018 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid
1019 * @doi_def: the DOI definition
1020 * @rngcat: category list
1021 * @rngcat_len: length of the category list in bytes
1022 *
1023 * Description:
1024 * Checks the given categories against the given DOI definition and returns a
1025 * negative value if any of the categories do not have a valid mapping and a
1026 * zero value if all of the categories are valid.
1027 *
1028 */
1029static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def,
1030 const unsigned char *rngcat,
1031 u32 rngcat_len)
1032{
1033 u16 cat_high;
1034 u16 cat_low;
1035 u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1;
1036 u32 iter;
1037
1038 if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01)
1039 return -EFAULT;
1040
1041 for (iter = 0; iter < rngcat_len; iter += 4) {
1042 cat_high = get_unaligned_be16(&rngcat[iter]);
1043 if ((iter + 4) <= rngcat_len)
1044 cat_low = get_unaligned_be16(&rngcat[iter + 2]);
1045 else
1046 cat_low = 0;
1047
1048 if (cat_high > cat_prev)
1049 return -EFAULT;
1050
1051 cat_prev = cat_low;
1052 }
1053
1054 return 0;
1055}
1056
1057/**
1058 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network
1059 * @doi_def: the DOI definition
1060 * @secattr: the security attributes
1061 * @net_cat: the zero'd out category list in network/CIPSO format
1062 * @net_cat_len: the length of the CIPSO category list in bytes
1063 *
1064 * Description:
1065 * Perform a label mapping to translate a local MLS category bitmap to the
1066 * correct CIPSO category list using the given DOI definition. Returns the
1067 * size in bytes of the network category bitmap on success, negative values
1068 * otherwise.
1069 *
1070 */
1071static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def,
1072 const struct netlbl_lsm_secattr *secattr,
1073 unsigned char *net_cat,
1074 u32 net_cat_len)
1075{
1076 int iter = -1;
1077 u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2];
1078 u32 array_cnt = 0;
1079 u32 cat_size = 0;
1080
1081 /* make sure we don't overflow the 'array[]' variable */
1082 if (net_cat_len >
1083 (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN))
1084 return -ENOSPC;
1085
1086 for (;;) {
1087 iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1);
1088 if (iter < 0)
1089 break;
1090 cat_size += (iter == 0 ? 0 : sizeof(u16));
1091 if (cat_size > net_cat_len)
1092 return -ENOSPC;
1093 array[array_cnt++] = iter;
1094
1095 iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter);
1096 if (iter < 0)
1097 return -EFAULT;
1098 cat_size += sizeof(u16);
1099 if (cat_size > net_cat_len)
1100 return -ENOSPC;
1101 array[array_cnt++] = iter;
1102 }
1103
1104 for (iter = 0; array_cnt > 0;) {
1105 *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]);
1106 iter += 2;
1107 array_cnt--;
1108 if (array[array_cnt] != 0) {
1109 *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]);
1110 iter += 2;
1111 }
1112 }
1113
1114 return cat_size;
1115}
1116
1117/**
1118 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host
1119 * @doi_def: the DOI definition
1120 * @net_cat: the category list in network/CIPSO format
1121 * @net_cat_len: the length of the CIPSO bitmap in bytes
1122 * @secattr: the security attributes
1123 *
1124 * Description:
1125 * Perform a label mapping to translate a CIPSO category list to the correct
1126 * local MLS category bitmap using the given DOI definition. Returns zero on
1127 * success, negative values on failure.
1128 *
1129 */
1130static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def,
1131 const unsigned char *net_cat,
1132 u32 net_cat_len,
1133 struct netlbl_lsm_secattr *secattr)
1134{
1135 int ret_val;
1136 u32 net_iter;
1137 u16 cat_low;
1138 u16 cat_high;
1139
1140 for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) {
1141 cat_high = get_unaligned_be16(&net_cat[net_iter]);
1142 if ((net_iter + 4) <= net_cat_len)
1143 cat_low = get_unaligned_be16(&net_cat[net_iter + 2]);
1144 else
1145 cat_low = 0;
1146
1147 ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat,
1148 cat_low,
1149 cat_high,
1150 GFP_ATOMIC);
1151 if (ret_val != 0)
1152 return ret_val;
1153 }
1154
1155 return 0;
1156}
1157
1158/*
1159 * Protocol Handling Functions
1160 */
1161
1162/**
1163 * cipso_v4_gentag_hdr - Generate a CIPSO option header
1164 * @doi_def: the DOI definition
1165 * @len: the total tag length in bytes, not including this header
1166 * @buf: the CIPSO option buffer
1167 *
1168 * Description:
1169 * Write a CIPSO header into the beginning of @buffer.
1170 *
1171 */
1172static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
1173 unsigned char *buf,
1174 u32 len)
1175{
1176 buf[0] = IPOPT_CIPSO;
1177 buf[1] = CIPSO_V4_HDR_LEN + len;
1178 *(__be32 *)&buf[2] = htonl(doi_def->doi);
1179}
1180
1181/**
1182 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1)
1183 * @doi_def: the DOI definition
1184 * @secattr: the security attributes
1185 * @buffer: the option buffer
1186 * @buffer_len: length of buffer in bytes
1187 *
1188 * Description:
1189 * Generate a CIPSO option using the restricted bitmap tag, tag type #1. The
1190 * actual buffer length may be larger than the indicated size due to
1191 * translation between host and network category bitmaps. Returns the size of
1192 * the tag on success, negative values on failure.
1193 *
1194 */
1195static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
1196 const struct netlbl_lsm_secattr *secattr,
1197 unsigned char *buffer,
1198 u32 buffer_len)
1199{
1200 int ret_val;
1201 u32 tag_len;
1202 u32 level;
1203
1204 if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
1205 return -EPERM;
1206
1207 ret_val = cipso_v4_map_lvl_hton(doi_def,
1208 secattr->attr.mls.lvl,
1209 &level);
1210 if (ret_val != 0)
1211 return ret_val;
1212
1213 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1214 ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
1215 secattr,
1216 &buffer[4],
1217 buffer_len - 4);
1218 if (ret_val < 0)
1219 return ret_val;
1220
1221 /* This will send packets using the "optimized" format when
1222 * possible as specified in section 3.4.2.6 of the
1223 * CIPSO draft. */
1224 if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10)
1225 tag_len = 14;
1226 else
1227 tag_len = 4 + ret_val;
1228 } else
1229 tag_len = 4;
1230
1231 buffer[0] = CIPSO_V4_TAG_RBITMAP;
1232 buffer[1] = tag_len;
1233 buffer[3] = level;
1234
1235 return tag_len;
1236}
1237
1238/**
1239 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag
1240 * @doi_def: the DOI definition
1241 * @tag: the CIPSO tag
1242 * @secattr: the security attributes
1243 *
1244 * Description:
1245 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security
1246 * attributes in @secattr. Return zero on success, negatives values on
1247 * failure.
1248 *
1249 */
1250static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
1251 const unsigned char *tag,
1252 struct netlbl_lsm_secattr *secattr)
1253{
1254 int ret_val;
1255 u8 tag_len = tag[1];
1256 u32 level;
1257
1258 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1259 if (ret_val != 0)
1260 return ret_val;
1261 secattr->attr.mls.lvl = level;
1262 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1263
1264 if (tag_len > 4) {
1265 ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
1266 &tag[4],
1267 tag_len - 4,
1268 secattr);
1269 if (ret_val != 0) {
1270 netlbl_catmap_free(secattr->attr.mls.cat);
1271 return ret_val;
1272 }
1273
1274 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1275 }
1276
1277 return 0;
1278}
1279
1280/**
1281 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2)
1282 * @doi_def: the DOI definition
1283 * @secattr: the security attributes
1284 * @buffer: the option buffer
1285 * @buffer_len: length of buffer in bytes
1286 *
1287 * Description:
1288 * Generate a CIPSO option using the enumerated tag, tag type #2. Returns the
1289 * size of the tag on success, negative values on failure.
1290 *
1291 */
1292static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def,
1293 const struct netlbl_lsm_secattr *secattr,
1294 unsigned char *buffer,
1295 u32 buffer_len)
1296{
1297 int ret_val;
1298 u32 tag_len;
1299 u32 level;
1300
1301 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1302 return -EPERM;
1303
1304 ret_val = cipso_v4_map_lvl_hton(doi_def,
1305 secattr->attr.mls.lvl,
1306 &level);
1307 if (ret_val != 0)
1308 return ret_val;
1309
1310 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1311 ret_val = cipso_v4_map_cat_enum_hton(doi_def,
1312 secattr,
1313 &buffer[4],
1314 buffer_len - 4);
1315 if (ret_val < 0)
1316 return ret_val;
1317
1318 tag_len = 4 + ret_val;
1319 } else
1320 tag_len = 4;
1321
1322 buffer[0] = CIPSO_V4_TAG_ENUM;
1323 buffer[1] = tag_len;
1324 buffer[3] = level;
1325
1326 return tag_len;
1327}
1328
1329/**
1330 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag
1331 * @doi_def: the DOI definition
1332 * @tag: the CIPSO tag
1333 * @secattr: the security attributes
1334 *
1335 * Description:
1336 * Parse a CIPSO enumerated tag (tag type #2) and return the security
1337 * attributes in @secattr. Return zero on success, negatives values on
1338 * failure.
1339 *
1340 */
1341static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def,
1342 const unsigned char *tag,
1343 struct netlbl_lsm_secattr *secattr)
1344{
1345 int ret_val;
1346 u8 tag_len = tag[1];
1347 u32 level;
1348
1349 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1350 if (ret_val != 0)
1351 return ret_val;
1352 secattr->attr.mls.lvl = level;
1353 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1354
1355 if (tag_len > 4) {
1356 ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
1357 &tag[4],
1358 tag_len - 4,
1359 secattr);
1360 if (ret_val != 0) {
1361 netlbl_catmap_free(secattr->attr.mls.cat);
1362 return ret_val;
1363 }
1364
1365 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1366 }
1367
1368 return 0;
1369}
1370
1371/**
1372 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5)
1373 * @doi_def: the DOI definition
1374 * @secattr: the security attributes
1375 * @buffer: the option buffer
1376 * @buffer_len: length of buffer in bytes
1377 *
1378 * Description:
1379 * Generate a CIPSO option using the ranged tag, tag type #5. Returns the
1380 * size of the tag on success, negative values on failure.
1381 *
1382 */
1383static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def,
1384 const struct netlbl_lsm_secattr *secattr,
1385 unsigned char *buffer,
1386 u32 buffer_len)
1387{
1388 int ret_val;
1389 u32 tag_len;
1390 u32 level;
1391
1392 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1393 return -EPERM;
1394
1395 ret_val = cipso_v4_map_lvl_hton(doi_def,
1396 secattr->attr.mls.lvl,
1397 &level);
1398 if (ret_val != 0)
1399 return ret_val;
1400
1401 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1402 ret_val = cipso_v4_map_cat_rng_hton(doi_def,
1403 secattr,
1404 &buffer[4],
1405 buffer_len - 4);
1406 if (ret_val < 0)
1407 return ret_val;
1408
1409 tag_len = 4 + ret_val;
1410 } else
1411 tag_len = 4;
1412
1413 buffer[0] = CIPSO_V4_TAG_RANGE;
1414 buffer[1] = tag_len;
1415 buffer[3] = level;
1416
1417 return tag_len;
1418}
1419
1420/**
1421 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag
1422 * @doi_def: the DOI definition
1423 * @tag: the CIPSO tag
1424 * @secattr: the security attributes
1425 *
1426 * Description:
1427 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes
1428 * in @secattr. Return zero on success, negatives values on failure.
1429 *
1430 */
1431static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def,
1432 const unsigned char *tag,
1433 struct netlbl_lsm_secattr *secattr)
1434{
1435 int ret_val;
1436 u8 tag_len = tag[1];
1437 u32 level;
1438
1439 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1440 if (ret_val != 0)
1441 return ret_val;
1442 secattr->attr.mls.lvl = level;
1443 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1444
1445 if (tag_len > 4) {
1446 ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
1447 &tag[4],
1448 tag_len - 4,
1449 secattr);
1450 if (ret_val != 0) {
1451 netlbl_catmap_free(secattr->attr.mls.cat);
1452 return ret_val;
1453 }
1454
1455 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1456 }
1457
1458 return 0;
1459}
1460
1461/**
1462 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard)
1463 * @doi_def: the DOI definition
1464 * @secattr: the security attributes
1465 * @buffer: the option buffer
1466 * @buffer_len: length of buffer in bytes
1467 *
1468 * Description:
1469 * Generate a CIPSO option using the local tag. Returns the size of the tag
1470 * on success, negative values on failure.
1471 *
1472 */
1473static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
1474 const struct netlbl_lsm_secattr *secattr,
1475 unsigned char *buffer,
1476 u32 buffer_len)
1477{
1478 if (!(secattr->flags & NETLBL_SECATTR_SECID))
1479 return -EPERM;
1480
1481 buffer[0] = CIPSO_V4_TAG_LOCAL;
1482 buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
1483 *(u32 *)&buffer[2] = secattr->attr.secid;
1484
1485 return CIPSO_V4_TAG_LOC_BLEN;
1486}
1487
1488/**
1489 * cipso_v4_parsetag_loc - Parse a CIPSO local tag
1490 * @doi_def: the DOI definition
1491 * @tag: the CIPSO tag
1492 * @secattr: the security attributes
1493 *
1494 * Description:
1495 * Parse a CIPSO local tag and return the security attributes in @secattr.
1496 * Return zero on success, negatives values on failure.
1497 *
1498 */
1499static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
1500 const unsigned char *tag,
1501 struct netlbl_lsm_secattr *secattr)
1502{
1503 secattr->attr.secid = *(u32 *)&tag[2];
1504 secattr->flags |= NETLBL_SECATTR_SECID;
1505
1506 return 0;
1507}
1508
1509/**
1510 * cipso_v4_optptr - Find the CIPSO option in the packet
1511 * @skb: the packet
1512 *
1513 * Description:
1514 * Parse the packet's IP header looking for a CIPSO option. Returns a pointer
1515 * to the start of the CIPSO option on success, NULL if one if not found.
1516 *
1517 */
1518unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
1519{
1520 const struct iphdr *iph = ip_hdr(skb);
1521 unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]);
1522 int optlen;
1523 int taglen;
1524
1525 for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) {
1526 switch (optptr[0]) {
1527 case IPOPT_CIPSO:
1528 return optptr;
1529 case IPOPT_END:
1530 return NULL;
1531 case IPOPT_NOOP:
1532 taglen = 1;
1533 break;
1534 default:
1535 taglen = optptr[1];
1536 }
1537 optlen -= taglen;
1538 optptr += taglen;
1539 }
1540
1541 return NULL;
1542}
1543
1544/**
1545 * cipso_v4_validate - Validate a CIPSO option
1546 * @option: the start of the option, on error it is set to point to the error
1547 *
1548 * Description:
1549 * This routine is called to validate a CIPSO option, it checks all of the
1550 * fields to ensure that they are at least valid, see the draft snippet below
1551 * for details. If the option is valid then a zero value is returned and
1552 * the value of @option is unchanged. If the option is invalid then a
1553 * non-zero value is returned and @option is adjusted to point to the
1554 * offending portion of the option. From the IETF draft ...
1555 *
1556 * "If any field within the CIPSO options, such as the DOI identifier, is not
1557 * recognized the IP datagram is discarded and an ICMP 'parameter problem'
1558 * (type 12) is generated and returned. The ICMP code field is set to 'bad
1559 * parameter' (code 0) and the pointer is set to the start of the CIPSO field
1560 * that is unrecognized."
1561 *
1562 */
1563int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
1564{
1565 unsigned char *opt = *option;
1566 unsigned char *tag;
1567 unsigned char opt_iter;
1568 unsigned char err_offset = 0;
1569 u8 opt_len;
1570 u8 tag_len;
1571 struct cipso_v4_doi *doi_def = NULL;
1572 u32 tag_iter;
1573
1574 /* caller already checks for length values that are too large */
1575 opt_len = opt[1];
1576 if (opt_len < 8) {
1577 err_offset = 1;
1578 goto validate_return;
1579 }
1580
1581 rcu_read_lock();
1582 doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2]));
1583 if (!doi_def) {
1584 err_offset = 2;
1585 goto validate_return_locked;
1586 }
1587
1588 opt_iter = CIPSO_V4_HDR_LEN;
1589 tag = opt + opt_iter;
1590 while (opt_iter < opt_len) {
1591 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
1592 if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
1593 ++tag_iter == CIPSO_V4_TAG_MAXCNT) {
1594 err_offset = opt_iter;
1595 goto validate_return_locked;
1596 }
1597
1598 if (opt_iter + 1 == opt_len) {
1599 err_offset = opt_iter;
1600 goto validate_return_locked;
1601 }
1602 tag_len = tag[1];
1603 if (tag_len > (opt_len - opt_iter)) {
1604 err_offset = opt_iter + 1;
1605 goto validate_return_locked;
1606 }
1607
1608 switch (tag[0]) {
1609 case CIPSO_V4_TAG_RBITMAP:
1610 if (tag_len < CIPSO_V4_TAG_RBM_BLEN) {
1611 err_offset = opt_iter + 1;
1612 goto validate_return_locked;
1613 }
1614
1615 /* We are already going to do all the verification
1616 * necessary at the socket layer so from our point of
1617 * view it is safe to turn these checks off (and less
1618 * work), however, the CIPSO draft says we should do
1619 * all the CIPSO validations here but it doesn't
1620 * really specify _exactly_ what we need to validate
1621 * ... so, just make it a sysctl tunable. */
1622 if (cipso_v4_rbm_strictvalid) {
1623 if (cipso_v4_map_lvl_valid(doi_def,
1624 tag[3]) < 0) {
1625 err_offset = opt_iter + 3;
1626 goto validate_return_locked;
1627 }
1628 if (tag_len > CIPSO_V4_TAG_RBM_BLEN &&
1629 cipso_v4_map_cat_rbm_valid(doi_def,
1630 &tag[4],
1631 tag_len - 4) < 0) {
1632 err_offset = opt_iter + 4;
1633 goto validate_return_locked;
1634 }
1635 }
1636 break;
1637 case CIPSO_V4_TAG_ENUM:
1638 if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) {
1639 err_offset = opt_iter + 1;
1640 goto validate_return_locked;
1641 }
1642
1643 if (cipso_v4_map_lvl_valid(doi_def,
1644 tag[3]) < 0) {
1645 err_offset = opt_iter + 3;
1646 goto validate_return_locked;
1647 }
1648 if (tag_len > CIPSO_V4_TAG_ENUM_BLEN &&
1649 cipso_v4_map_cat_enum_valid(doi_def,
1650 &tag[4],
1651 tag_len - 4) < 0) {
1652 err_offset = opt_iter + 4;
1653 goto validate_return_locked;
1654 }
1655 break;
1656 case CIPSO_V4_TAG_RANGE:
1657 if (tag_len < CIPSO_V4_TAG_RNG_BLEN) {
1658 err_offset = opt_iter + 1;
1659 goto validate_return_locked;
1660 }
1661
1662 if (cipso_v4_map_lvl_valid(doi_def,
1663 tag[3]) < 0) {
1664 err_offset = opt_iter + 3;
1665 goto validate_return_locked;
1666 }
1667 if (tag_len > CIPSO_V4_TAG_RNG_BLEN &&
1668 cipso_v4_map_cat_rng_valid(doi_def,
1669 &tag[4],
1670 tag_len - 4) < 0) {
1671 err_offset = opt_iter + 4;
1672 goto validate_return_locked;
1673 }
1674 break;
1675 case CIPSO_V4_TAG_LOCAL:
1676 /* This is a non-standard tag that we only allow for
1677 * local connections, so if the incoming interface is
1678 * not the loopback device drop the packet. Further,
1679 * there is no legitimate reason for setting this from
1680 * userspace so reject it if skb is NULL. */
1681 if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) {
1682 err_offset = opt_iter;
1683 goto validate_return_locked;
1684 }
1685 if (tag_len != CIPSO_V4_TAG_LOC_BLEN) {
1686 err_offset = opt_iter + 1;
1687 goto validate_return_locked;
1688 }
1689 break;
1690 default:
1691 err_offset = opt_iter;
1692 goto validate_return_locked;
1693 }
1694
1695 tag += tag_len;
1696 opt_iter += tag_len;
1697 }
1698
1699validate_return_locked:
1700 rcu_read_unlock();
1701validate_return:
1702 *option = opt + err_offset;
1703 return err_offset;
1704}
1705
1706/**
1707 * cipso_v4_error - Send the correct response for a bad packet
1708 * @skb: the packet
1709 * @error: the error code
1710 * @gateway: CIPSO gateway flag
1711 *
1712 * Description:
1713 * Based on the error code given in @error, send an ICMP error message back to
1714 * the originating host. From the IETF draft ...
1715 *
1716 * "If the contents of the CIPSO [option] are valid but the security label is
1717 * outside of the configured host or port label range, the datagram is
1718 * discarded and an ICMP 'destination unreachable' (type 3) is generated and
1719 * returned. The code field of the ICMP is set to 'communication with
1720 * destination network administratively prohibited' (code 9) or to
1721 * 'communication with destination host administratively prohibited'
1722 * (code 10). The value of the code is dependent on whether the originator
1723 * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The
1724 * recipient of the ICMP message MUST be able to handle either value. The
1725 * same procedure is performed if a CIPSO [option] can not be added to an
1726 * IP packet because it is too large to fit in the IP options area."
1727 *
1728 * "If the error is triggered by receipt of an ICMP message, the message is
1729 * discarded and no response is permitted (consistent with general ICMP
1730 * processing rules)."
1731 *
1732 */
1733void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
1734{
1735 if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
1736 return;
1737
1738 if (gateway)
1739 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
1740 else
1741 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
1742}
1743
1744/**
1745 * cipso_v4_genopt - Generate a CIPSO option
1746 * @buf: the option buffer
1747 * @buf_len: the size of opt_buf
1748 * @doi_def: the CIPSO DOI to use
1749 * @secattr: the security attributes
1750 *
1751 * Description:
1752 * Generate a CIPSO option using the DOI definition and security attributes
1753 * passed to the function. Returns the length of the option on success and
1754 * negative values on failure.
1755 *
1756 */
1757static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
1758 const struct cipso_v4_doi *doi_def,
1759 const struct netlbl_lsm_secattr *secattr)
1760{
1761 int ret_val;
1762 u32 iter;
1763
1764 if (buf_len <= CIPSO_V4_HDR_LEN)
1765 return -ENOSPC;
1766
1767 /* XXX - This code assumes only one tag per CIPSO option which isn't
1768 * really a good assumption to make but since we only support the MAC
1769 * tags right now it is a safe assumption. */
1770 iter = 0;
1771 do {
1772 memset(buf, 0, buf_len);
1773 switch (doi_def->tags[iter]) {
1774 case CIPSO_V4_TAG_RBITMAP:
1775 ret_val = cipso_v4_gentag_rbm(doi_def,
1776 secattr,
1777 &buf[CIPSO_V4_HDR_LEN],
1778 buf_len - CIPSO_V4_HDR_LEN);
1779 break;
1780 case CIPSO_V4_TAG_ENUM:
1781 ret_val = cipso_v4_gentag_enum(doi_def,
1782 secattr,
1783 &buf[CIPSO_V4_HDR_LEN],
1784 buf_len - CIPSO_V4_HDR_LEN);
1785 break;
1786 case CIPSO_V4_TAG_RANGE:
1787 ret_val = cipso_v4_gentag_rng(doi_def,
1788 secattr,
1789 &buf[CIPSO_V4_HDR_LEN],
1790 buf_len - CIPSO_V4_HDR_LEN);
1791 break;
1792 case CIPSO_V4_TAG_LOCAL:
1793 ret_val = cipso_v4_gentag_loc(doi_def,
1794 secattr,
1795 &buf[CIPSO_V4_HDR_LEN],
1796 buf_len - CIPSO_V4_HDR_LEN);
1797 break;
1798 default:
1799 return -EPERM;
1800 }
1801
1802 iter++;
1803 } while (ret_val < 0 &&
1804 iter < CIPSO_V4_TAG_MAXCNT &&
1805 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
1806 if (ret_val < 0)
1807 return ret_val;
1808 cipso_v4_gentag_hdr(doi_def, buf, ret_val);
1809 return CIPSO_V4_HDR_LEN + ret_val;
1810}
1811
1812/**
1813 * cipso_v4_sock_setattr - Add a CIPSO option to a socket
1814 * @sk: the socket
1815 * @doi_def: the CIPSO DOI to use
1816 * @secattr: the specific security attributes of the socket
1817 *
1818 * Description:
1819 * Set the CIPSO option on the given socket using the DOI definition and
1820 * security attributes passed to the function. This function requires
1821 * exclusive access to @sk, which means it either needs to be in the
1822 * process of being created or locked. Returns zero on success and negative
1823 * values on failure.
1824 *
1825 */
1826int cipso_v4_sock_setattr(struct sock *sk,
1827 const struct cipso_v4_doi *doi_def,
1828 const struct netlbl_lsm_secattr *secattr)
1829{
1830 int ret_val = -EPERM;
1831 unsigned char *buf = NULL;
1832 u32 buf_len;
1833 u32 opt_len;
1834 struct ip_options_rcu *old, *opt = NULL;
1835 struct inet_sock *sk_inet;
1836 struct inet_connection_sock *sk_conn;
1837
1838 /* In the case of sock_create_lite(), the sock->sk field is not
1839 * defined yet but it is not a problem as the only users of these
1840 * "lite" PF_INET sockets are functions which do an accept() call
1841 * afterwards so we will label the socket as part of the accept(). */
1842 if (!sk)
1843 return 0;
1844
1845 /* We allocate the maximum CIPSO option size here so we are probably
1846 * being a little wasteful, but it makes our life _much_ easier later
1847 * on and after all we are only talking about 40 bytes. */
1848 buf_len = CIPSO_V4_OPT_LEN_MAX;
1849 buf = kmalloc(buf_len, GFP_ATOMIC);
1850 if (!buf) {
1851 ret_val = -ENOMEM;
1852 goto socket_setattr_failure;
1853 }
1854
1855 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1856 if (ret_val < 0)
1857 goto socket_setattr_failure;
1858 buf_len = ret_val;
1859
1860 /* We can't use ip_options_get() directly because it makes a call to
1861 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1862 * we won't always have CAP_NET_RAW even though we _always_ want to
1863 * set the IPOPT_CIPSO option. */
1864 opt_len = (buf_len + 3) & ~3;
1865 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1866 if (!opt) {
1867 ret_val = -ENOMEM;
1868 goto socket_setattr_failure;
1869 }
1870 memcpy(opt->opt.__data, buf, buf_len);
1871 opt->opt.optlen = opt_len;
1872 opt->opt.cipso = sizeof(struct iphdr);
1873 kfree(buf);
1874 buf = NULL;
1875
1876 sk_inet = inet_sk(sk);
1877
1878 old = rcu_dereference_protected(sk_inet->inet_opt,
1879 lockdep_sock_is_held(sk));
1880 if (sk_inet->is_icsk) {
1881 sk_conn = inet_csk(sk);
1882 if (old)
1883 sk_conn->icsk_ext_hdr_len -= old->opt.optlen;
1884 sk_conn->icsk_ext_hdr_len += opt->opt.optlen;
1885 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
1886 }
1887 rcu_assign_pointer(sk_inet->inet_opt, opt);
1888 if (old)
1889 kfree_rcu(old, rcu);
1890
1891 return 0;
1892
1893socket_setattr_failure:
1894 kfree(buf);
1895 kfree(opt);
1896 return ret_val;
1897}
1898
1899/**
1900 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket
1901 * @req: the connection request socket
1902 * @doi_def: the CIPSO DOI to use
1903 * @secattr: the specific security attributes of the socket
1904 *
1905 * Description:
1906 * Set the CIPSO option on the given socket using the DOI definition and
1907 * security attributes passed to the function. Returns zero on success and
1908 * negative values on failure.
1909 *
1910 */
1911int cipso_v4_req_setattr(struct request_sock *req,
1912 const struct cipso_v4_doi *doi_def,
1913 const struct netlbl_lsm_secattr *secattr)
1914{
1915 int ret_val = -EPERM;
1916 unsigned char *buf = NULL;
1917 u32 buf_len;
1918 u32 opt_len;
1919 struct ip_options_rcu *opt = NULL;
1920 struct inet_request_sock *req_inet;
1921
1922 /* We allocate the maximum CIPSO option size here so we are probably
1923 * being a little wasteful, but it makes our life _much_ easier later
1924 * on and after all we are only talking about 40 bytes. */
1925 buf_len = CIPSO_V4_OPT_LEN_MAX;
1926 buf = kmalloc(buf_len, GFP_ATOMIC);
1927 if (!buf) {
1928 ret_val = -ENOMEM;
1929 goto req_setattr_failure;
1930 }
1931
1932 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1933 if (ret_val < 0)
1934 goto req_setattr_failure;
1935 buf_len = ret_val;
1936
1937 /* We can't use ip_options_get() directly because it makes a call to
1938 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1939 * we won't always have CAP_NET_RAW even though we _always_ want to
1940 * set the IPOPT_CIPSO option. */
1941 opt_len = (buf_len + 3) & ~3;
1942 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1943 if (!opt) {
1944 ret_val = -ENOMEM;
1945 goto req_setattr_failure;
1946 }
1947 memcpy(opt->opt.__data, buf, buf_len);
1948 opt->opt.optlen = opt_len;
1949 opt->opt.cipso = sizeof(struct iphdr);
1950 kfree(buf);
1951 buf = NULL;
1952
1953 req_inet = inet_rsk(req);
1954 opt = xchg((__force struct ip_options_rcu **)&req_inet->ireq_opt, opt);
1955 if (opt)
1956 kfree_rcu(opt, rcu);
1957
1958 return 0;
1959
1960req_setattr_failure:
1961 kfree(buf);
1962 kfree(opt);
1963 return ret_val;
1964}
1965
1966/**
1967 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options
1968 * @opt_ptr: IP option pointer
1969 *
1970 * Description:
1971 * Deletes the CIPSO IP option from a set of IP options and makes the necessary
1972 * adjustments to the IP option structure. Returns zero on success, negative
1973 * values on failure.
1974 *
1975 */
1976static int cipso_v4_delopt(struct ip_options_rcu __rcu **opt_ptr)
1977{
1978 struct ip_options_rcu *opt = rcu_dereference_protected(*opt_ptr, 1);
1979 int hdr_delta = 0;
1980
1981 if (!opt || opt->opt.cipso == 0)
1982 return 0;
1983 if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) {
1984 u8 cipso_len;
1985 u8 cipso_off;
1986 unsigned char *cipso_ptr;
1987 int iter;
1988 int optlen_new;
1989
1990 cipso_off = opt->opt.cipso - sizeof(struct iphdr);
1991 cipso_ptr = &opt->opt.__data[cipso_off];
1992 cipso_len = cipso_ptr[1];
1993
1994 if (opt->opt.srr > opt->opt.cipso)
1995 opt->opt.srr -= cipso_len;
1996 if (opt->opt.rr > opt->opt.cipso)
1997 opt->opt.rr -= cipso_len;
1998 if (opt->opt.ts > opt->opt.cipso)
1999 opt->opt.ts -= cipso_len;
2000 if (opt->opt.router_alert > opt->opt.cipso)
2001 opt->opt.router_alert -= cipso_len;
2002 opt->opt.cipso = 0;
2003
2004 memmove(cipso_ptr, cipso_ptr + cipso_len,
2005 opt->opt.optlen - cipso_off - cipso_len);
2006
2007 /* determining the new total option length is tricky because of
2008 * the padding necessary, the only thing i can think to do at
2009 * this point is walk the options one-by-one, skipping the
2010 * padding at the end to determine the actual option size and
2011 * from there we can determine the new total option length */
2012 iter = 0;
2013 optlen_new = 0;
2014 while (iter < opt->opt.optlen)
2015 if (opt->opt.__data[iter] != IPOPT_NOP) {
2016 iter += opt->opt.__data[iter + 1];
2017 optlen_new = iter;
2018 } else
2019 iter++;
2020 hdr_delta = opt->opt.optlen;
2021 opt->opt.optlen = (optlen_new + 3) & ~3;
2022 hdr_delta -= opt->opt.optlen;
2023 } else {
2024 /* only the cipso option was present on the socket so we can
2025 * remove the entire option struct */
2026 *opt_ptr = NULL;
2027 hdr_delta = opt->opt.optlen;
2028 kfree_rcu(opt, rcu);
2029 }
2030
2031 return hdr_delta;
2032}
2033
2034/**
2035 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket
2036 * @sk: the socket
2037 *
2038 * Description:
2039 * Removes the CIPSO option from a socket, if present.
2040 *
2041 */
2042void cipso_v4_sock_delattr(struct sock *sk)
2043{
2044 struct inet_sock *sk_inet;
2045 int hdr_delta;
2046
2047 sk_inet = inet_sk(sk);
2048
2049 hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt);
2050 if (sk_inet->is_icsk && hdr_delta > 0) {
2051 struct inet_connection_sock *sk_conn = inet_csk(sk);
2052 sk_conn->icsk_ext_hdr_len -= hdr_delta;
2053 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
2054 }
2055}
2056
2057/**
2058 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket
2059 * @reg: the request socket
2060 *
2061 * Description:
2062 * Removes the CIPSO option from a request socket, if present.
2063 *
2064 */
2065void cipso_v4_req_delattr(struct request_sock *req)
2066{
2067 cipso_v4_delopt(&inet_rsk(req)->ireq_opt);
2068}
2069
2070/**
2071 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
2072 * @cipso: the CIPSO v4 option
2073 * @secattr: the security attributes
2074 *
2075 * Description:
2076 * Inspect @cipso and return the security attributes in @secattr. Returns zero
2077 * on success and negative values on failure.
2078 *
2079 */
2080int cipso_v4_getattr(const unsigned char *cipso,
2081 struct netlbl_lsm_secattr *secattr)
2082{
2083 int ret_val = -ENOMSG;
2084 u32 doi;
2085 struct cipso_v4_doi *doi_def;
2086
2087 if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0)
2088 return 0;
2089
2090 doi = get_unaligned_be32(&cipso[2]);
2091 rcu_read_lock();
2092 doi_def = cipso_v4_doi_search(doi);
2093 if (!doi_def)
2094 goto getattr_return;
2095 /* XXX - This code assumes only one tag per CIPSO option which isn't
2096 * really a good assumption to make but since we only support the MAC
2097 * tags right now it is a safe assumption. */
2098 switch (cipso[6]) {
2099 case CIPSO_V4_TAG_RBITMAP:
2100 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr);
2101 break;
2102 case CIPSO_V4_TAG_ENUM:
2103 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr);
2104 break;
2105 case CIPSO_V4_TAG_RANGE:
2106 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr);
2107 break;
2108 case CIPSO_V4_TAG_LOCAL:
2109 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr);
2110 break;
2111 }
2112 if (ret_val == 0)
2113 secattr->type = NETLBL_NLTYPE_CIPSOV4;
2114
2115getattr_return:
2116 rcu_read_unlock();
2117 return ret_val;
2118}
2119
2120/**
2121 * cipso_v4_sock_getattr - Get the security attributes from a sock
2122 * @sk: the sock
2123 * @secattr: the security attributes
2124 *
2125 * Description:
2126 * Query @sk to see if there is a CIPSO option attached to the sock and if
2127 * there is return the CIPSO security attributes in @secattr. This function
2128 * requires that @sk be locked, or privately held, but it does not do any
2129 * locking itself. Returns zero on success and negative values on failure.
2130 *
2131 */
2132int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
2133{
2134 struct ip_options_rcu *opt;
2135 int res = -ENOMSG;
2136
2137 rcu_read_lock();
2138 opt = rcu_dereference(inet_sk(sk)->inet_opt);
2139 if (opt && opt->opt.cipso)
2140 res = cipso_v4_getattr(opt->opt.__data +
2141 opt->opt.cipso -
2142 sizeof(struct iphdr),
2143 secattr);
2144 rcu_read_unlock();
2145 return res;
2146}
2147
2148/**
2149 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
2150 * @skb: the packet
2151 * @secattr: the security attributes
2152 *
2153 * Description:
2154 * Set the CIPSO option on the given packet based on the security attributes.
2155 * Returns a pointer to the IP header on success and NULL on failure.
2156 *
2157 */
2158int cipso_v4_skbuff_setattr(struct sk_buff *skb,
2159 const struct cipso_v4_doi *doi_def,
2160 const struct netlbl_lsm_secattr *secattr)
2161{
2162 int ret_val;
2163 struct iphdr *iph;
2164 struct ip_options *opt = &IPCB(skb)->opt;
2165 unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
2166 u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
2167 u32 opt_len;
2168 int len_delta;
2169
2170 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
2171 if (ret_val < 0)
2172 return ret_val;
2173 buf_len = ret_val;
2174 opt_len = (buf_len + 3) & ~3;
2175
2176 /* we overwrite any existing options to ensure that we have enough
2177 * room for the CIPSO option, the reason is that we _need_ to guarantee
2178 * that the security label is applied to the packet - we do the same
2179 * thing when using the socket options and it hasn't caused a problem,
2180 * if we need to we can always revisit this choice later */
2181
2182 len_delta = opt_len - opt->optlen;
2183 /* if we don't ensure enough headroom we could panic on the skb_push()
2184 * call below so make sure we have enough, we are also "mangling" the
2185 * packet so we should probably do a copy-on-write call anyway */
2186 ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
2187 if (ret_val < 0)
2188 return ret_val;
2189
2190 if (len_delta > 0) {
2191 /* we assume that the header + opt->optlen have already been
2192 * "pushed" in ip_options_build() or similar */
2193 iph = ip_hdr(skb);
2194 skb_push(skb, len_delta);
2195 memmove((char *)iph - len_delta, iph, iph->ihl << 2);
2196 skb_reset_network_header(skb);
2197 iph = ip_hdr(skb);
2198 } else if (len_delta < 0) {
2199 iph = ip_hdr(skb);
2200 memset(iph + 1, IPOPT_NOP, opt->optlen);
2201 } else
2202 iph = ip_hdr(skb);
2203
2204 if (opt->optlen > 0)
2205 memset(opt, 0, sizeof(*opt));
2206 opt->optlen = opt_len;
2207 opt->cipso = sizeof(struct iphdr);
2208 opt->is_changed = 1;
2209
2210 /* we have to do the following because we are being called from a
2211 * netfilter hook which means the packet already has had the header
2212 * fields populated and the checksum calculated - yes this means we
2213 * are doing more work than needed but we do it to keep the core
2214 * stack clean and tidy */
2215 memcpy(iph + 1, buf, buf_len);
2216 if (opt_len > buf_len)
2217 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
2218 if (len_delta != 0) {
2219 iph->ihl = 5 + (opt_len >> 2);
2220 iph->tot_len = htons(skb->len);
2221 }
2222 ip_send_check(iph);
2223
2224 return 0;
2225}
2226
2227/**
2228 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
2229 * @skb: the packet
2230 *
2231 * Description:
2232 * Removes any and all CIPSO options from the given packet. Returns zero on
2233 * success, negative values on failure.
2234 *
2235 */
2236int cipso_v4_skbuff_delattr(struct sk_buff *skb)
2237{
2238 int ret_val;
2239 struct iphdr *iph;
2240 struct ip_options *opt = &IPCB(skb)->opt;
2241 unsigned char *cipso_ptr;
2242
2243 if (opt->cipso == 0)
2244 return 0;
2245
2246 /* since we are changing the packet we should make a copy */
2247 ret_val = skb_cow(skb, skb_headroom(skb));
2248 if (ret_val < 0)
2249 return ret_val;
2250
2251 /* the easiest thing to do is just replace the cipso option with noop
2252 * options since we don't change the size of the packet, although we
2253 * still need to recalculate the checksum */
2254
2255 iph = ip_hdr(skb);
2256 cipso_ptr = (unsigned char *)iph + opt->cipso;
2257 memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]);
2258 opt->cipso = 0;
2259 opt->is_changed = 1;
2260
2261 ip_send_check(iph);
2262
2263 return 0;
2264}
2265
2266/*
2267 * Setup Functions
2268 */
2269
2270/**
2271 * cipso_v4_init - Initialize the CIPSO module
2272 *
2273 * Description:
2274 * Initialize the CIPSO module and prepare it for use. Returns zero on success
2275 * and negative values on failure.
2276 *
2277 */
2278static int __init cipso_v4_init(void)
2279{
2280 int ret_val;
2281
2282 ret_val = cipso_v4_cache_init();
2283 if (ret_val != 0)
2284 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
2285 ret_val);
2286
2287 return 0;
2288}
2289
2290subsys_initcall(cipso_v4_init);
2291