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 ((level < doi_def->map.std->lvl.cipso_size) &&
671 (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL))
672 return 0;
673 break;
674 }
675
676 return -EFAULT;
677}
678
679/**
680 * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
681 * @doi_def: the DOI definition
682 * @host_lvl: the host MLS level
683 * @net_lvl: the network/CIPSO MLS level
684 *
685 * Description:
686 * Perform a label mapping to translate a local MLS level to the correct
687 * CIPSO level using the given DOI definition. Returns zero on success,
688 * negative values otherwise.
689 *
690 */
691static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
692 u32 host_lvl,
693 u32 *net_lvl)
694{
695 switch (doi_def->type) {
696 case CIPSO_V4_MAP_PASS:
697 *net_lvl = host_lvl;
698 return 0;
699 case CIPSO_V4_MAP_TRANS:
700 if (host_lvl < doi_def->map.std->lvl.local_size &&
701 doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) {
702 *net_lvl = doi_def->map.std->lvl.local[host_lvl];
703 return 0;
704 }
705 return -EPERM;
706 }
707
708 return -EINVAL;
709}
710
711/**
712 * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
713 * @doi_def: the DOI definition
714 * @net_lvl: the network/CIPSO MLS level
715 * @host_lvl: the host MLS level
716 *
717 * Description:
718 * Perform a label mapping to translate a CIPSO level to the correct local MLS
719 * level using the given DOI definition. Returns zero on success, negative
720 * values otherwise.
721 *
722 */
723static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
724 u32 net_lvl,
725 u32 *host_lvl)
726{
727 struct cipso_v4_std_map_tbl *map_tbl;
728
729 switch (doi_def->type) {
730 case CIPSO_V4_MAP_PASS:
731 *host_lvl = net_lvl;
732 return 0;
733 case CIPSO_V4_MAP_TRANS:
734 map_tbl = doi_def->map.std;
735 if (net_lvl < map_tbl->lvl.cipso_size &&
736 map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
737 *host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
738 return 0;
739 }
740 return -EPERM;
741 }
742
743 return -EINVAL;
744}
745
746/**
747 * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
748 * @doi_def: the DOI definition
749 * @bitmap: category bitmap
750 * @bitmap_len: bitmap length in bytes
751 *
752 * Description:
753 * Checks the given category bitmap against the given DOI definition and
754 * returns a negative value if any of the categories in the bitmap do not have
755 * a valid mapping and a zero value if all of the categories are valid.
756 *
757 */
758static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
759 const unsigned char *bitmap,
760 u32 bitmap_len)
761{
762 int cat = -1;
763 u32 bitmap_len_bits = bitmap_len * 8;
764 u32 cipso_cat_size;
765 u32 *cipso_array;
766
767 switch (doi_def->type) {
768 case CIPSO_V4_MAP_PASS:
769 return 0;
770 case CIPSO_V4_MAP_TRANS:
771 cipso_cat_size = doi_def->map.std->cat.cipso_size;
772 cipso_array = doi_def->map.std->cat.cipso;
773 for (;;) {
774 cat = netlbl_bitmap_walk(bitmap,
775 bitmap_len_bits,
776 cat + 1,
777 1);
778 if (cat < 0)
779 break;
780 if (cat >= cipso_cat_size ||
781 cipso_array[cat] >= CIPSO_V4_INV_CAT)
782 return -EFAULT;
783 }
784
785 if (cat == -1)
786 return 0;
787 break;
788 }
789
790 return -EFAULT;
791}
792
793/**
794 * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
795 * @doi_def: the DOI definition
796 * @secattr: the security attributes
797 * @net_cat: the zero'd out category bitmap in network/CIPSO format
798 * @net_cat_len: the length of the CIPSO bitmap in bytes
799 *
800 * Description:
801 * Perform a label mapping to translate a local MLS category bitmap to the
802 * correct CIPSO bitmap using the given DOI definition. Returns the minimum
803 * size in bytes of the network bitmap on success, negative values otherwise.
804 *
805 */
806static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
807 const struct netlbl_lsm_secattr *secattr,
808 unsigned char *net_cat,
809 u32 net_cat_len)
810{
811 int host_spot = -1;
812 u32 net_spot = CIPSO_V4_INV_CAT;
813 u32 net_spot_max = 0;
814 u32 net_clen_bits = net_cat_len * 8;
815 u32 host_cat_size = 0;
816 u32 *host_cat_array = NULL;
817
818 if (doi_def->type == CIPSO_V4_MAP_TRANS) {
819 host_cat_size = doi_def->map.std->cat.local_size;
820 host_cat_array = doi_def->map.std->cat.local;
821 }
822
823 for (;;) {
824 host_spot = netlbl_catmap_walk(secattr->attr.mls.cat,
825 host_spot + 1);
826 if (host_spot < 0)
827 break;
828
829 switch (doi_def->type) {
830 case CIPSO_V4_MAP_PASS:
831 net_spot = host_spot;
832 break;
833 case CIPSO_V4_MAP_TRANS:
834 if (host_spot >= host_cat_size)
835 return -EPERM;
836 net_spot = host_cat_array[host_spot];
837 if (net_spot >= CIPSO_V4_INV_CAT)
838 return -EPERM;
839 break;
840 }
841 if (net_spot >= net_clen_bits)
842 return -ENOSPC;
843 netlbl_bitmap_setbit(net_cat, net_spot, 1);
844
845 if (net_spot > net_spot_max)
846 net_spot_max = net_spot;
847 }
848
849 if (++net_spot_max % 8)
850 return net_spot_max / 8 + 1;
851 return net_spot_max / 8;
852}
853
854/**
855 * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host
856 * @doi_def: the DOI definition
857 * @net_cat: the category bitmap in network/CIPSO format
858 * @net_cat_len: the length of the CIPSO bitmap in bytes
859 * @secattr: the security attributes
860 *
861 * Description:
862 * Perform a label mapping to translate a CIPSO bitmap to the correct local
863 * MLS category bitmap using the given DOI definition. Returns zero on
864 * success, negative values on failure.
865 *
866 */
867static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
868 const unsigned char *net_cat,
869 u32 net_cat_len,
870 struct netlbl_lsm_secattr *secattr)
871{
872 int ret_val;
873 int net_spot = -1;
874 u32 host_spot = CIPSO_V4_INV_CAT;
875 u32 net_clen_bits = net_cat_len * 8;
876 u32 net_cat_size = 0;
877 u32 *net_cat_array = NULL;
878
879 if (doi_def->type == CIPSO_V4_MAP_TRANS) {
880 net_cat_size = doi_def->map.std->cat.cipso_size;
881 net_cat_array = doi_def->map.std->cat.cipso;
882 }
883
884 for (;;) {
885 net_spot = netlbl_bitmap_walk(net_cat,
886 net_clen_bits,
887 net_spot + 1,
888 1);
889 if (net_spot < 0) {
890 if (net_spot == -2)
891 return -EFAULT;
892 return 0;
893 }
894
895 switch (doi_def->type) {
896 case CIPSO_V4_MAP_PASS:
897 host_spot = net_spot;
898 break;
899 case CIPSO_V4_MAP_TRANS:
900 if (net_spot >= net_cat_size)
901 return -EPERM;
902 host_spot = net_cat_array[net_spot];
903 if (host_spot >= CIPSO_V4_INV_CAT)
904 return -EPERM;
905 break;
906 }
907 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
908 host_spot,
909 GFP_ATOMIC);
910 if (ret_val != 0)
911 return ret_val;
912 }
913
914 return -EINVAL;
915}
916
917/**
918 * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid
919 * @doi_def: the DOI definition
920 * @enumcat: category list
921 * @enumcat_len: length of the category list in bytes
922 *
923 * Description:
924 * Checks the given categories against the given DOI definition and returns a
925 * negative value if any of the categories do not have a valid mapping and a
926 * zero value if all of the categories are valid.
927 *
928 */
929static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def,
930 const unsigned char *enumcat,
931 u32 enumcat_len)
932{
933 u16 cat;
934 int cat_prev = -1;
935 u32 iter;
936
937 if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01)
938 return -EFAULT;
939
940 for (iter = 0; iter < enumcat_len; iter += 2) {
941 cat = get_unaligned_be16(&enumcat[iter]);
942 if (cat <= cat_prev)
943 return -EFAULT;
944 cat_prev = cat;
945 }
946
947 return 0;
948}
949
950/**
951 * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network
952 * @doi_def: the DOI definition
953 * @secattr: the security attributes
954 * @net_cat: the zero'd out category list in network/CIPSO format
955 * @net_cat_len: the length of the CIPSO category list in bytes
956 *
957 * Description:
958 * Perform a label mapping to translate a local MLS category bitmap to the
959 * correct CIPSO category list using the given DOI definition. Returns the
960 * size in bytes of the network category bitmap on success, negative values
961 * otherwise.
962 *
963 */
964static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def,
965 const struct netlbl_lsm_secattr *secattr,
966 unsigned char *net_cat,
967 u32 net_cat_len)
968{
969 int cat = -1;
970 u32 cat_iter = 0;
971
972 for (;;) {
973 cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1);
974 if (cat < 0)
975 break;
976 if ((cat_iter + 2) > net_cat_len)
977 return -ENOSPC;
978
979 *((__be16 *)&net_cat[cat_iter]) = htons(cat);
980 cat_iter += 2;
981 }
982
983 return cat_iter;
984}
985
986/**
987 * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host
988 * @doi_def: the DOI definition
989 * @net_cat: the category list in network/CIPSO format
990 * @net_cat_len: the length of the CIPSO bitmap in bytes
991 * @secattr: the security attributes
992 *
993 * Description:
994 * Perform a label mapping to translate a CIPSO category list to the correct
995 * local MLS category bitmap using the given DOI definition. Returns zero on
996 * success, negative values on failure.
997 *
998 */
999static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def,
1000 const unsigned char *net_cat,
1001 u32 net_cat_len,
1002 struct netlbl_lsm_secattr *secattr)
1003{
1004 int ret_val;
1005 u32 iter;
1006
1007 for (iter = 0; iter < net_cat_len; iter += 2) {
1008 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
1009 get_unaligned_be16(&net_cat[iter]),
1010 GFP_ATOMIC);
1011 if (ret_val != 0)
1012 return ret_val;
1013 }
1014
1015 return 0;
1016}
1017
1018/**
1019 * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid
1020 * @doi_def: the DOI definition
1021 * @rngcat: category list
1022 * @rngcat_len: length of the category list in bytes
1023 *
1024 * Description:
1025 * Checks the given categories against the given DOI definition and returns a
1026 * negative value if any of the categories do not have a valid mapping and a
1027 * zero value if all of the categories are valid.
1028 *
1029 */
1030static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def,
1031 const unsigned char *rngcat,
1032 u32 rngcat_len)
1033{
1034 u16 cat_high;
1035 u16 cat_low;
1036 u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1;
1037 u32 iter;
1038
1039 if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01)
1040 return -EFAULT;
1041
1042 for (iter = 0; iter < rngcat_len; iter += 4) {
1043 cat_high = get_unaligned_be16(&rngcat[iter]);
1044 if ((iter + 4) <= rngcat_len)
1045 cat_low = get_unaligned_be16(&rngcat[iter + 2]);
1046 else
1047 cat_low = 0;
1048
1049 if (cat_high > cat_prev)
1050 return -EFAULT;
1051
1052 cat_prev = cat_low;
1053 }
1054
1055 return 0;
1056}
1057
1058/**
1059 * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network
1060 * @doi_def: the DOI definition
1061 * @secattr: the security attributes
1062 * @net_cat: the zero'd out category list in network/CIPSO format
1063 * @net_cat_len: the length of the CIPSO category list in bytes
1064 *
1065 * Description:
1066 * Perform a label mapping to translate a local MLS category bitmap to the
1067 * correct CIPSO category list using the given DOI definition. Returns the
1068 * size in bytes of the network category bitmap on success, negative values
1069 * otherwise.
1070 *
1071 */
1072static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def,
1073 const struct netlbl_lsm_secattr *secattr,
1074 unsigned char *net_cat,
1075 u32 net_cat_len)
1076{
1077 int iter = -1;
1078 u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2];
1079 u32 array_cnt = 0;
1080 u32 cat_size = 0;
1081
1082 /* make sure we don't overflow the 'array[]' variable */
1083 if (net_cat_len >
1084 (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN))
1085 return -ENOSPC;
1086
1087 for (;;) {
1088 iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1);
1089 if (iter < 0)
1090 break;
1091 cat_size += (iter == 0 ? 0 : sizeof(u16));
1092 if (cat_size > net_cat_len)
1093 return -ENOSPC;
1094 array[array_cnt++] = iter;
1095
1096 iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter);
1097 if (iter < 0)
1098 return -EFAULT;
1099 cat_size += sizeof(u16);
1100 if (cat_size > net_cat_len)
1101 return -ENOSPC;
1102 array[array_cnt++] = iter;
1103 }
1104
1105 for (iter = 0; array_cnt > 0;) {
1106 *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]);
1107 iter += 2;
1108 array_cnt--;
1109 if (array[array_cnt] != 0) {
1110 *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]);
1111 iter += 2;
1112 }
1113 }
1114
1115 return cat_size;
1116}
1117
1118/**
1119 * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host
1120 * @doi_def: the DOI definition
1121 * @net_cat: the category list in network/CIPSO format
1122 * @net_cat_len: the length of the CIPSO bitmap in bytes
1123 * @secattr: the security attributes
1124 *
1125 * Description:
1126 * Perform a label mapping to translate a CIPSO category list to the correct
1127 * local MLS category bitmap using the given DOI definition. Returns zero on
1128 * success, negative values on failure.
1129 *
1130 */
1131static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def,
1132 const unsigned char *net_cat,
1133 u32 net_cat_len,
1134 struct netlbl_lsm_secattr *secattr)
1135{
1136 int ret_val;
1137 u32 net_iter;
1138 u16 cat_low;
1139 u16 cat_high;
1140
1141 for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) {
1142 cat_high = get_unaligned_be16(&net_cat[net_iter]);
1143 if ((net_iter + 4) <= net_cat_len)
1144 cat_low = get_unaligned_be16(&net_cat[net_iter + 2]);
1145 else
1146 cat_low = 0;
1147
1148 ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat,
1149 cat_low,
1150 cat_high,
1151 GFP_ATOMIC);
1152 if (ret_val != 0)
1153 return ret_val;
1154 }
1155
1156 return 0;
1157}
1158
1159/*
1160 * Protocol Handling Functions
1161 */
1162
1163/**
1164 * cipso_v4_gentag_hdr - Generate a CIPSO option header
1165 * @doi_def: the DOI definition
1166 * @len: the total tag length in bytes, not including this header
1167 * @buf: the CIPSO option buffer
1168 *
1169 * Description:
1170 * Write a CIPSO header into the beginning of @buffer.
1171 *
1172 */
1173static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
1174 unsigned char *buf,
1175 u32 len)
1176{
1177 buf[0] = IPOPT_CIPSO;
1178 buf[1] = CIPSO_V4_HDR_LEN + len;
1179 *(__be32 *)&buf[2] = htonl(doi_def->doi);
1180}
1181
1182/**
1183 * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1)
1184 * @doi_def: the DOI definition
1185 * @secattr: the security attributes
1186 * @buffer: the option buffer
1187 * @buffer_len: length of buffer in bytes
1188 *
1189 * Description:
1190 * Generate a CIPSO option using the restricted bitmap tag, tag type #1. The
1191 * actual buffer length may be larger than the indicated size due to
1192 * translation between host and network category bitmaps. Returns the size of
1193 * the tag on success, negative values on failure.
1194 *
1195 */
1196static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
1197 const struct netlbl_lsm_secattr *secattr,
1198 unsigned char *buffer,
1199 u32 buffer_len)
1200{
1201 int ret_val;
1202 u32 tag_len;
1203 u32 level;
1204
1205 if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
1206 return -EPERM;
1207
1208 ret_val = cipso_v4_map_lvl_hton(doi_def,
1209 secattr->attr.mls.lvl,
1210 &level);
1211 if (ret_val != 0)
1212 return ret_val;
1213
1214 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1215 ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
1216 secattr,
1217 &buffer[4],
1218 buffer_len - 4);
1219 if (ret_val < 0)
1220 return ret_val;
1221
1222 /* This will send packets using the "optimized" format when
1223 * possible as specified in section 3.4.2.6 of the
1224 * CIPSO draft. */
1225 if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10)
1226 tag_len = 14;
1227 else
1228 tag_len = 4 + ret_val;
1229 } else
1230 tag_len = 4;
1231
1232 buffer[0] = CIPSO_V4_TAG_RBITMAP;
1233 buffer[1] = tag_len;
1234 buffer[3] = level;
1235
1236 return tag_len;
1237}
1238
1239/**
1240 * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag
1241 * @doi_def: the DOI definition
1242 * @tag: the CIPSO tag
1243 * @secattr: the security attributes
1244 *
1245 * Description:
1246 * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security
1247 * attributes in @secattr. Return zero on success, negatives values on
1248 * failure.
1249 *
1250 */
1251static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
1252 const unsigned char *tag,
1253 struct netlbl_lsm_secattr *secattr)
1254{
1255 int ret_val;
1256 u8 tag_len = tag[1];
1257 u32 level;
1258
1259 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1260 if (ret_val != 0)
1261 return ret_val;
1262 secattr->attr.mls.lvl = level;
1263 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1264
1265 if (tag_len > 4) {
1266 ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
1267 &tag[4],
1268 tag_len - 4,
1269 secattr);
1270 if (ret_val != 0) {
1271 netlbl_catmap_free(secattr->attr.mls.cat);
1272 return ret_val;
1273 }
1274
1275 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1276 }
1277
1278 return 0;
1279}
1280
1281/**
1282 * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2)
1283 * @doi_def: the DOI definition
1284 * @secattr: the security attributes
1285 * @buffer: the option buffer
1286 * @buffer_len: length of buffer in bytes
1287 *
1288 * Description:
1289 * Generate a CIPSO option using the enumerated tag, tag type #2. Returns the
1290 * size of the tag on success, negative values on failure.
1291 *
1292 */
1293static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def,
1294 const struct netlbl_lsm_secattr *secattr,
1295 unsigned char *buffer,
1296 u32 buffer_len)
1297{
1298 int ret_val;
1299 u32 tag_len;
1300 u32 level;
1301
1302 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1303 return -EPERM;
1304
1305 ret_val = cipso_v4_map_lvl_hton(doi_def,
1306 secattr->attr.mls.lvl,
1307 &level);
1308 if (ret_val != 0)
1309 return ret_val;
1310
1311 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1312 ret_val = cipso_v4_map_cat_enum_hton(doi_def,
1313 secattr,
1314 &buffer[4],
1315 buffer_len - 4);
1316 if (ret_val < 0)
1317 return ret_val;
1318
1319 tag_len = 4 + ret_val;
1320 } else
1321 tag_len = 4;
1322
1323 buffer[0] = CIPSO_V4_TAG_ENUM;
1324 buffer[1] = tag_len;
1325 buffer[3] = level;
1326
1327 return tag_len;
1328}
1329
1330/**
1331 * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag
1332 * @doi_def: the DOI definition
1333 * @tag: the CIPSO tag
1334 * @secattr: the security attributes
1335 *
1336 * Description:
1337 * Parse a CIPSO enumerated tag (tag type #2) and return the security
1338 * attributes in @secattr. Return zero on success, negatives values on
1339 * failure.
1340 *
1341 */
1342static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def,
1343 const unsigned char *tag,
1344 struct netlbl_lsm_secattr *secattr)
1345{
1346 int ret_val;
1347 u8 tag_len = tag[1];
1348 u32 level;
1349
1350 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1351 if (ret_val != 0)
1352 return ret_val;
1353 secattr->attr.mls.lvl = level;
1354 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1355
1356 if (tag_len > 4) {
1357 ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
1358 &tag[4],
1359 tag_len - 4,
1360 secattr);
1361 if (ret_val != 0) {
1362 netlbl_catmap_free(secattr->attr.mls.cat);
1363 return ret_val;
1364 }
1365
1366 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1367 }
1368
1369 return 0;
1370}
1371
1372/**
1373 * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5)
1374 * @doi_def: the DOI definition
1375 * @secattr: the security attributes
1376 * @buffer: the option buffer
1377 * @buffer_len: length of buffer in bytes
1378 *
1379 * Description:
1380 * Generate a CIPSO option using the ranged tag, tag type #5. Returns the
1381 * size of the tag on success, negative values on failure.
1382 *
1383 */
1384static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def,
1385 const struct netlbl_lsm_secattr *secattr,
1386 unsigned char *buffer,
1387 u32 buffer_len)
1388{
1389 int ret_val;
1390 u32 tag_len;
1391 u32 level;
1392
1393 if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1394 return -EPERM;
1395
1396 ret_val = cipso_v4_map_lvl_hton(doi_def,
1397 secattr->attr.mls.lvl,
1398 &level);
1399 if (ret_val != 0)
1400 return ret_val;
1401
1402 if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1403 ret_val = cipso_v4_map_cat_rng_hton(doi_def,
1404 secattr,
1405 &buffer[4],
1406 buffer_len - 4);
1407 if (ret_val < 0)
1408 return ret_val;
1409
1410 tag_len = 4 + ret_val;
1411 } else
1412 tag_len = 4;
1413
1414 buffer[0] = CIPSO_V4_TAG_RANGE;
1415 buffer[1] = tag_len;
1416 buffer[3] = level;
1417
1418 return tag_len;
1419}
1420
1421/**
1422 * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag
1423 * @doi_def: the DOI definition
1424 * @tag: the CIPSO tag
1425 * @secattr: the security attributes
1426 *
1427 * Description:
1428 * Parse a CIPSO ranged tag (tag type #5) and return the security attributes
1429 * in @secattr. Return zero on success, negatives values on failure.
1430 *
1431 */
1432static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def,
1433 const unsigned char *tag,
1434 struct netlbl_lsm_secattr *secattr)
1435{
1436 int ret_val;
1437 u8 tag_len = tag[1];
1438 u32 level;
1439
1440 ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1441 if (ret_val != 0)
1442 return ret_val;
1443 secattr->attr.mls.lvl = level;
1444 secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1445
1446 if (tag_len > 4) {
1447 ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
1448 &tag[4],
1449 tag_len - 4,
1450 secattr);
1451 if (ret_val != 0) {
1452 netlbl_catmap_free(secattr->attr.mls.cat);
1453 return ret_val;
1454 }
1455
1456 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1457 }
1458
1459 return 0;
1460}
1461
1462/**
1463 * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard)
1464 * @doi_def: the DOI definition
1465 * @secattr: the security attributes
1466 * @buffer: the option buffer
1467 * @buffer_len: length of buffer in bytes
1468 *
1469 * Description:
1470 * Generate a CIPSO option using the local tag. Returns the size of the tag
1471 * on success, negative values on failure.
1472 *
1473 */
1474static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
1475 const struct netlbl_lsm_secattr *secattr,
1476 unsigned char *buffer,
1477 u32 buffer_len)
1478{
1479 if (!(secattr->flags & NETLBL_SECATTR_SECID))
1480 return -EPERM;
1481
1482 buffer[0] = CIPSO_V4_TAG_LOCAL;
1483 buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
1484 *(u32 *)&buffer[2] = secattr->attr.secid;
1485
1486 return CIPSO_V4_TAG_LOC_BLEN;
1487}
1488
1489/**
1490 * cipso_v4_parsetag_loc - Parse a CIPSO local tag
1491 * @doi_def: the DOI definition
1492 * @tag: the CIPSO tag
1493 * @secattr: the security attributes
1494 *
1495 * Description:
1496 * Parse a CIPSO local tag and return the security attributes in @secattr.
1497 * Return zero on success, negatives values on failure.
1498 *
1499 */
1500static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
1501 const unsigned char *tag,
1502 struct netlbl_lsm_secattr *secattr)
1503{
1504 secattr->attr.secid = *(u32 *)&tag[2];
1505 secattr->flags |= NETLBL_SECATTR_SECID;
1506
1507 return 0;
1508}
1509
1510/**
1511 * cipso_v4_optptr - Find the CIPSO option in the packet
1512 * @skb: the packet
1513 *
1514 * Description:
1515 * Parse the packet's IP header looking for a CIPSO option. Returns a pointer
1516 * to the start of the CIPSO option on success, NULL if one is not found.
1517 *
1518 */
1519unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
1520{
1521 const struct iphdr *iph = ip_hdr(skb);
1522 unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]);
1523 int optlen;
1524 int taglen;
1525
1526 for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 1; ) {
1527 switch (optptr[0]) {
1528 case IPOPT_END:
1529 return NULL;
1530 case IPOPT_NOOP:
1531 taglen = 1;
1532 break;
1533 default:
1534 taglen = optptr[1];
1535 }
1536 if (!taglen || taglen > optlen)
1537 return NULL;
1538 if (optptr[0] == IPOPT_CIPSO)
1539 return optptr;
1540
1541 optlen -= taglen;
1542 optptr += taglen;
1543 }
1544
1545 return NULL;
1546}
1547
1548/**
1549 * cipso_v4_validate - Validate a CIPSO option
1550 * @option: the start of the option, on error it is set to point to the error
1551 *
1552 * Description:
1553 * This routine is called to validate a CIPSO option, it checks all of the
1554 * fields to ensure that they are at least valid, see the draft snippet below
1555 * for details. If the option is valid then a zero value is returned and
1556 * the value of @option is unchanged. If the option is invalid then a
1557 * non-zero value is returned and @option is adjusted to point to the
1558 * offending portion of the option. From the IETF draft ...
1559 *
1560 * "If any field within the CIPSO options, such as the DOI identifier, is not
1561 * recognized the IP datagram is discarded and an ICMP 'parameter problem'
1562 * (type 12) is generated and returned. The ICMP code field is set to 'bad
1563 * parameter' (code 0) and the pointer is set to the start of the CIPSO field
1564 * that is unrecognized."
1565 *
1566 */
1567int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
1568{
1569 unsigned char *opt = *option;
1570 unsigned char *tag;
1571 unsigned char opt_iter;
1572 unsigned char err_offset = 0;
1573 u8 opt_len;
1574 u8 tag_len;
1575 struct cipso_v4_doi *doi_def = NULL;
1576 u32 tag_iter;
1577
1578 /* caller already checks for length values that are too large */
1579 opt_len = opt[1];
1580 if (opt_len < 8) {
1581 err_offset = 1;
1582 goto validate_return;
1583 }
1584
1585 rcu_read_lock();
1586 doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2]));
1587 if (!doi_def) {
1588 err_offset = 2;
1589 goto validate_return_locked;
1590 }
1591
1592 opt_iter = CIPSO_V4_HDR_LEN;
1593 tag = opt + opt_iter;
1594 while (opt_iter < opt_len) {
1595 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
1596 if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
1597 ++tag_iter == CIPSO_V4_TAG_MAXCNT) {
1598 err_offset = opt_iter;
1599 goto validate_return_locked;
1600 }
1601
1602 if (opt_iter + 1 == opt_len) {
1603 err_offset = opt_iter;
1604 goto validate_return_locked;
1605 }
1606 tag_len = tag[1];
1607 if (tag_len > (opt_len - opt_iter)) {
1608 err_offset = opt_iter + 1;
1609 goto validate_return_locked;
1610 }
1611
1612 switch (tag[0]) {
1613 case CIPSO_V4_TAG_RBITMAP:
1614 if (tag_len < CIPSO_V4_TAG_RBM_BLEN) {
1615 err_offset = opt_iter + 1;
1616 goto validate_return_locked;
1617 }
1618
1619 /* We are already going to do all the verification
1620 * necessary at the socket layer so from our point of
1621 * view it is safe to turn these checks off (and less
1622 * work), however, the CIPSO draft says we should do
1623 * all the CIPSO validations here but it doesn't
1624 * really specify _exactly_ what we need to validate
1625 * ... so, just make it a sysctl tunable. */
1626 if (cipso_v4_rbm_strictvalid) {
1627 if (cipso_v4_map_lvl_valid(doi_def,
1628 tag[3]) < 0) {
1629 err_offset = opt_iter + 3;
1630 goto validate_return_locked;
1631 }
1632 if (tag_len > CIPSO_V4_TAG_RBM_BLEN &&
1633 cipso_v4_map_cat_rbm_valid(doi_def,
1634 &tag[4],
1635 tag_len - 4) < 0) {
1636 err_offset = opt_iter + 4;
1637 goto validate_return_locked;
1638 }
1639 }
1640 break;
1641 case CIPSO_V4_TAG_ENUM:
1642 if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) {
1643 err_offset = opt_iter + 1;
1644 goto validate_return_locked;
1645 }
1646
1647 if (cipso_v4_map_lvl_valid(doi_def,
1648 tag[3]) < 0) {
1649 err_offset = opt_iter + 3;
1650 goto validate_return_locked;
1651 }
1652 if (tag_len > CIPSO_V4_TAG_ENUM_BLEN &&
1653 cipso_v4_map_cat_enum_valid(doi_def,
1654 &tag[4],
1655 tag_len - 4) < 0) {
1656 err_offset = opt_iter + 4;
1657 goto validate_return_locked;
1658 }
1659 break;
1660 case CIPSO_V4_TAG_RANGE:
1661 if (tag_len < CIPSO_V4_TAG_RNG_BLEN) {
1662 err_offset = opt_iter + 1;
1663 goto validate_return_locked;
1664 }
1665
1666 if (cipso_v4_map_lvl_valid(doi_def,
1667 tag[3]) < 0) {
1668 err_offset = opt_iter + 3;
1669 goto validate_return_locked;
1670 }
1671 if (tag_len > CIPSO_V4_TAG_RNG_BLEN &&
1672 cipso_v4_map_cat_rng_valid(doi_def,
1673 &tag[4],
1674 tag_len - 4) < 0) {
1675 err_offset = opt_iter + 4;
1676 goto validate_return_locked;
1677 }
1678 break;
1679 case CIPSO_V4_TAG_LOCAL:
1680 /* This is a non-standard tag that we only allow for
1681 * local connections, so if the incoming interface is
1682 * not the loopback device drop the packet. Further,
1683 * there is no legitimate reason for setting this from
1684 * userspace so reject it if skb is NULL. */
1685 if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) {
1686 err_offset = opt_iter;
1687 goto validate_return_locked;
1688 }
1689 if (tag_len != CIPSO_V4_TAG_LOC_BLEN) {
1690 err_offset = opt_iter + 1;
1691 goto validate_return_locked;
1692 }
1693 break;
1694 default:
1695 err_offset = opt_iter;
1696 goto validate_return_locked;
1697 }
1698
1699 tag += tag_len;
1700 opt_iter += tag_len;
1701 }
1702
1703validate_return_locked:
1704 rcu_read_unlock();
1705validate_return:
1706 *option = opt + err_offset;
1707 return err_offset;
1708}
1709
1710/**
1711 * cipso_v4_error - Send the correct response for a bad packet
1712 * @skb: the packet
1713 * @error: the error code
1714 * @gateway: CIPSO gateway flag
1715 *
1716 * Description:
1717 * Based on the error code given in @error, send an ICMP error message back to
1718 * the originating host. From the IETF draft ...
1719 *
1720 * "If the contents of the CIPSO [option] are valid but the security label is
1721 * outside of the configured host or port label range, the datagram is
1722 * discarded and an ICMP 'destination unreachable' (type 3) is generated and
1723 * returned. The code field of the ICMP is set to 'communication with
1724 * destination network administratively prohibited' (code 9) or to
1725 * 'communication with destination host administratively prohibited'
1726 * (code 10). The value of the code is dependent on whether the originator
1727 * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The
1728 * recipient of the ICMP message MUST be able to handle either value. The
1729 * same procedure is performed if a CIPSO [option] can not be added to an
1730 * IP packet because it is too large to fit in the IP options area."
1731 *
1732 * "If the error is triggered by receipt of an ICMP message, the message is
1733 * discarded and no response is permitted (consistent with general ICMP
1734 * processing rules)."
1735 *
1736 */
1737void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
1738{
1739 unsigned char optbuf[sizeof(struct ip_options) + 40];
1740 struct ip_options *opt = (struct ip_options *)optbuf;
1741
1742 if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
1743 return;
1744
1745 /*
1746 * We might be called above the IP layer,
1747 * so we can not use icmp_send and IPCB here.
1748 */
1749
1750 memset(opt, 0, sizeof(struct ip_options));
1751 opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
1752 if (__ip_options_compile(dev_net(skb->dev), opt, skb, NULL))
1753 return;
1754
1755 if (gateway)
1756 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, opt);
1757 else
1758 __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, opt);
1759}
1760
1761/**
1762 * cipso_v4_genopt - Generate a CIPSO option
1763 * @buf: the option buffer
1764 * @buf_len: the size of opt_buf
1765 * @doi_def: the CIPSO DOI to use
1766 * @secattr: the security attributes
1767 *
1768 * Description:
1769 * Generate a CIPSO option using the DOI definition and security attributes
1770 * passed to the function. Returns the length of the option on success and
1771 * negative values on failure.
1772 *
1773 */
1774static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
1775 const struct cipso_v4_doi *doi_def,
1776 const struct netlbl_lsm_secattr *secattr)
1777{
1778 int ret_val;
1779 u32 iter;
1780
1781 if (buf_len <= CIPSO_V4_HDR_LEN)
1782 return -ENOSPC;
1783
1784 /* XXX - This code assumes only one tag per CIPSO option which isn't
1785 * really a good assumption to make but since we only support the MAC
1786 * tags right now it is a safe assumption. */
1787 iter = 0;
1788 do {
1789 memset(buf, 0, buf_len);
1790 switch (doi_def->tags[iter]) {
1791 case CIPSO_V4_TAG_RBITMAP:
1792 ret_val = cipso_v4_gentag_rbm(doi_def,
1793 secattr,
1794 &buf[CIPSO_V4_HDR_LEN],
1795 buf_len - CIPSO_V4_HDR_LEN);
1796 break;
1797 case CIPSO_V4_TAG_ENUM:
1798 ret_val = cipso_v4_gentag_enum(doi_def,
1799 secattr,
1800 &buf[CIPSO_V4_HDR_LEN],
1801 buf_len - CIPSO_V4_HDR_LEN);
1802 break;
1803 case CIPSO_V4_TAG_RANGE:
1804 ret_val = cipso_v4_gentag_rng(doi_def,
1805 secattr,
1806 &buf[CIPSO_V4_HDR_LEN],
1807 buf_len - CIPSO_V4_HDR_LEN);
1808 break;
1809 case CIPSO_V4_TAG_LOCAL:
1810 ret_val = cipso_v4_gentag_loc(doi_def,
1811 secattr,
1812 &buf[CIPSO_V4_HDR_LEN],
1813 buf_len - CIPSO_V4_HDR_LEN);
1814 break;
1815 default:
1816 return -EPERM;
1817 }
1818
1819 iter++;
1820 } while (ret_val < 0 &&
1821 iter < CIPSO_V4_TAG_MAXCNT &&
1822 doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
1823 if (ret_val < 0)
1824 return ret_val;
1825 cipso_v4_gentag_hdr(doi_def, buf, ret_val);
1826 return CIPSO_V4_HDR_LEN + ret_val;
1827}
1828
1829/**
1830 * cipso_v4_sock_setattr - Add a CIPSO option to a socket
1831 * @sk: the socket
1832 * @doi_def: the CIPSO DOI to use
1833 * @secattr: the specific security attributes of the socket
1834 *
1835 * Description:
1836 * Set the CIPSO option on the given socket using the DOI definition and
1837 * security attributes passed to the function. This function requires
1838 * exclusive access to @sk, which means it either needs to be in the
1839 * process of being created or locked. Returns zero on success and negative
1840 * values on failure.
1841 *
1842 */
1843int cipso_v4_sock_setattr(struct sock *sk,
1844 const struct cipso_v4_doi *doi_def,
1845 const struct netlbl_lsm_secattr *secattr)
1846{
1847 int ret_val = -EPERM;
1848 unsigned char *buf = NULL;
1849 u32 buf_len;
1850 u32 opt_len;
1851 struct ip_options_rcu *old, *opt = NULL;
1852 struct inet_sock *sk_inet;
1853 struct inet_connection_sock *sk_conn;
1854
1855 /* In the case of sock_create_lite(), the sock->sk field is not
1856 * defined yet but it is not a problem as the only users of these
1857 * "lite" PF_INET sockets are functions which do an accept() call
1858 * afterwards so we will label the socket as part of the accept(). */
1859 if (!sk)
1860 return 0;
1861
1862 /* We allocate the maximum CIPSO option size here so we are probably
1863 * being a little wasteful, but it makes our life _much_ easier later
1864 * on and after all we are only talking about 40 bytes. */
1865 buf_len = CIPSO_V4_OPT_LEN_MAX;
1866 buf = kmalloc(buf_len, GFP_ATOMIC);
1867 if (!buf) {
1868 ret_val = -ENOMEM;
1869 goto socket_setattr_failure;
1870 }
1871
1872 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1873 if (ret_val < 0)
1874 goto socket_setattr_failure;
1875 buf_len = ret_val;
1876
1877 /* We can't use ip_options_get() directly because it makes a call to
1878 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1879 * we won't always have CAP_NET_RAW even though we _always_ want to
1880 * set the IPOPT_CIPSO option. */
1881 opt_len = (buf_len + 3) & ~3;
1882 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1883 if (!opt) {
1884 ret_val = -ENOMEM;
1885 goto socket_setattr_failure;
1886 }
1887 memcpy(opt->opt.__data, buf, buf_len);
1888 opt->opt.optlen = opt_len;
1889 opt->opt.cipso = sizeof(struct iphdr);
1890 kfree(buf);
1891 buf = NULL;
1892
1893 sk_inet = inet_sk(sk);
1894
1895 old = rcu_dereference_protected(sk_inet->inet_opt,
1896 lockdep_sock_is_held(sk));
1897 if (sk_inet->is_icsk) {
1898 sk_conn = inet_csk(sk);
1899 if (old)
1900 sk_conn->icsk_ext_hdr_len -= old->opt.optlen;
1901 sk_conn->icsk_ext_hdr_len += opt->opt.optlen;
1902 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
1903 }
1904 rcu_assign_pointer(sk_inet->inet_opt, opt);
1905 if (old)
1906 kfree_rcu(old, rcu);
1907
1908 return 0;
1909
1910socket_setattr_failure:
1911 kfree(buf);
1912 kfree(opt);
1913 return ret_val;
1914}
1915
1916/**
1917 * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket
1918 * @req: the connection request socket
1919 * @doi_def: the CIPSO DOI to use
1920 * @secattr: the specific security attributes of the socket
1921 *
1922 * Description:
1923 * Set the CIPSO option on the given socket using the DOI definition and
1924 * security attributes passed to the function. Returns zero on success and
1925 * negative values on failure.
1926 *
1927 */
1928int cipso_v4_req_setattr(struct request_sock *req,
1929 const struct cipso_v4_doi *doi_def,
1930 const struct netlbl_lsm_secattr *secattr)
1931{
1932 int ret_val = -EPERM;
1933 unsigned char *buf = NULL;
1934 u32 buf_len;
1935 u32 opt_len;
1936 struct ip_options_rcu *opt = NULL;
1937 struct inet_request_sock *req_inet;
1938
1939 /* We allocate the maximum CIPSO option size here so we are probably
1940 * being a little wasteful, but it makes our life _much_ easier later
1941 * on and after all we are only talking about 40 bytes. */
1942 buf_len = CIPSO_V4_OPT_LEN_MAX;
1943 buf = kmalloc(buf_len, GFP_ATOMIC);
1944 if (!buf) {
1945 ret_val = -ENOMEM;
1946 goto req_setattr_failure;
1947 }
1948
1949 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1950 if (ret_val < 0)
1951 goto req_setattr_failure;
1952 buf_len = ret_val;
1953
1954 /* We can't use ip_options_get() directly because it makes a call to
1955 * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1956 * we won't always have CAP_NET_RAW even though we _always_ want to
1957 * set the IPOPT_CIPSO option. */
1958 opt_len = (buf_len + 3) & ~3;
1959 opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1960 if (!opt) {
1961 ret_val = -ENOMEM;
1962 goto req_setattr_failure;
1963 }
1964 memcpy(opt->opt.__data, buf, buf_len);
1965 opt->opt.optlen = opt_len;
1966 opt->opt.cipso = sizeof(struct iphdr);
1967 kfree(buf);
1968 buf = NULL;
1969
1970 req_inet = inet_rsk(req);
1971 opt = xchg((__force struct ip_options_rcu **)&req_inet->ireq_opt, opt);
1972 if (opt)
1973 kfree_rcu(opt, rcu);
1974
1975 return 0;
1976
1977req_setattr_failure:
1978 kfree(buf);
1979 kfree(opt);
1980 return ret_val;
1981}
1982
1983/**
1984 * cipso_v4_delopt - Delete the CIPSO option from a set of IP options
1985 * @opt_ptr: IP option pointer
1986 *
1987 * Description:
1988 * Deletes the CIPSO IP option from a set of IP options and makes the necessary
1989 * adjustments to the IP option structure. Returns zero on success, negative
1990 * values on failure.
1991 *
1992 */
1993static int cipso_v4_delopt(struct ip_options_rcu __rcu **opt_ptr)
1994{
1995 struct ip_options_rcu *opt = rcu_dereference_protected(*opt_ptr, 1);
1996 int hdr_delta = 0;
1997
1998 if (!opt || opt->opt.cipso == 0)
1999 return 0;
2000 if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) {
2001 u8 cipso_len;
2002 u8 cipso_off;
2003 unsigned char *cipso_ptr;
2004 int iter;
2005 int optlen_new;
2006
2007 cipso_off = opt->opt.cipso - sizeof(struct iphdr);
2008 cipso_ptr = &opt->opt.__data[cipso_off];
2009 cipso_len = cipso_ptr[1];
2010
2011 if (opt->opt.srr > opt->opt.cipso)
2012 opt->opt.srr -= cipso_len;
2013 if (opt->opt.rr > opt->opt.cipso)
2014 opt->opt.rr -= cipso_len;
2015 if (opt->opt.ts > opt->opt.cipso)
2016 opt->opt.ts -= cipso_len;
2017 if (opt->opt.router_alert > opt->opt.cipso)
2018 opt->opt.router_alert -= cipso_len;
2019 opt->opt.cipso = 0;
2020
2021 memmove(cipso_ptr, cipso_ptr + cipso_len,
2022 opt->opt.optlen - cipso_off - cipso_len);
2023
2024 /* determining the new total option length is tricky because of
2025 * the padding necessary, the only thing i can think to do at
2026 * this point is walk the options one-by-one, skipping the
2027 * padding at the end to determine the actual option size and
2028 * from there we can determine the new total option length */
2029 iter = 0;
2030 optlen_new = 0;
2031 while (iter < opt->opt.optlen)
2032 if (opt->opt.__data[iter] != IPOPT_NOP) {
2033 iter += opt->opt.__data[iter + 1];
2034 optlen_new = iter;
2035 } else
2036 iter++;
2037 hdr_delta = opt->opt.optlen;
2038 opt->opt.optlen = (optlen_new + 3) & ~3;
2039 hdr_delta -= opt->opt.optlen;
2040 } else {
2041 /* only the cipso option was present on the socket so we can
2042 * remove the entire option struct */
2043 *opt_ptr = NULL;
2044 hdr_delta = opt->opt.optlen;
2045 kfree_rcu(opt, rcu);
2046 }
2047
2048 return hdr_delta;
2049}
2050
2051/**
2052 * cipso_v4_sock_delattr - Delete the CIPSO option from a socket
2053 * @sk: the socket
2054 *
2055 * Description:
2056 * Removes the CIPSO option from a socket, if present.
2057 *
2058 */
2059void cipso_v4_sock_delattr(struct sock *sk)
2060{
2061 struct inet_sock *sk_inet;
2062 int hdr_delta;
2063
2064 sk_inet = inet_sk(sk);
2065
2066 hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt);
2067 if (sk_inet->is_icsk && hdr_delta > 0) {
2068 struct inet_connection_sock *sk_conn = inet_csk(sk);
2069 sk_conn->icsk_ext_hdr_len -= hdr_delta;
2070 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
2071 }
2072}
2073
2074/**
2075 * cipso_v4_req_delattr - Delete the CIPSO option from a request socket
2076 * @reg: the request socket
2077 *
2078 * Description:
2079 * Removes the CIPSO option from a request socket, if present.
2080 *
2081 */
2082void cipso_v4_req_delattr(struct request_sock *req)
2083{
2084 cipso_v4_delopt(&inet_rsk(req)->ireq_opt);
2085}
2086
2087/**
2088 * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
2089 * @cipso: the CIPSO v4 option
2090 * @secattr: the security attributes
2091 *
2092 * Description:
2093 * Inspect @cipso and return the security attributes in @secattr. Returns zero
2094 * on success and negative values on failure.
2095 *
2096 */
2097int cipso_v4_getattr(const unsigned char *cipso,
2098 struct netlbl_lsm_secattr *secattr)
2099{
2100 int ret_val = -ENOMSG;
2101 u32 doi;
2102 struct cipso_v4_doi *doi_def;
2103
2104 if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0)
2105 return 0;
2106
2107 doi = get_unaligned_be32(&cipso[2]);
2108 rcu_read_lock();
2109 doi_def = cipso_v4_doi_search(doi);
2110 if (!doi_def)
2111 goto getattr_return;
2112 /* XXX - This code assumes only one tag per CIPSO option which isn't
2113 * really a good assumption to make but since we only support the MAC
2114 * tags right now it is a safe assumption. */
2115 switch (cipso[6]) {
2116 case CIPSO_V4_TAG_RBITMAP:
2117 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr);
2118 break;
2119 case CIPSO_V4_TAG_ENUM:
2120 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr);
2121 break;
2122 case CIPSO_V4_TAG_RANGE:
2123 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr);
2124 break;
2125 case CIPSO_V4_TAG_LOCAL:
2126 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr);
2127 break;
2128 }
2129 if (ret_val == 0)
2130 secattr->type = NETLBL_NLTYPE_CIPSOV4;
2131
2132getattr_return:
2133 rcu_read_unlock();
2134 return ret_val;
2135}
2136
2137/**
2138 * cipso_v4_sock_getattr - Get the security attributes from a sock
2139 * @sk: the sock
2140 * @secattr: the security attributes
2141 *
2142 * Description:
2143 * Query @sk to see if there is a CIPSO option attached to the sock and if
2144 * there is return the CIPSO security attributes in @secattr. This function
2145 * requires that @sk be locked, or privately held, but it does not do any
2146 * locking itself. Returns zero on success and negative values on failure.
2147 *
2148 */
2149int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
2150{
2151 struct ip_options_rcu *opt;
2152 int res = -ENOMSG;
2153
2154 rcu_read_lock();
2155 opt = rcu_dereference(inet_sk(sk)->inet_opt);
2156 if (opt && opt->opt.cipso)
2157 res = cipso_v4_getattr(opt->opt.__data +
2158 opt->opt.cipso -
2159 sizeof(struct iphdr),
2160 secattr);
2161 rcu_read_unlock();
2162 return res;
2163}
2164
2165/**
2166 * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
2167 * @skb: the packet
2168 * @secattr: the security attributes
2169 *
2170 * Description:
2171 * Set the CIPSO option on the given packet based on the security attributes.
2172 * Returns a pointer to the IP header on success and NULL on failure.
2173 *
2174 */
2175int cipso_v4_skbuff_setattr(struct sk_buff *skb,
2176 const struct cipso_v4_doi *doi_def,
2177 const struct netlbl_lsm_secattr *secattr)
2178{
2179 int ret_val;
2180 struct iphdr *iph;
2181 struct ip_options *opt = &IPCB(skb)->opt;
2182 unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
2183 u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
2184 u32 opt_len;
2185 int len_delta;
2186
2187 ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
2188 if (ret_val < 0)
2189 return ret_val;
2190 buf_len = ret_val;
2191 opt_len = (buf_len + 3) & ~3;
2192
2193 /* we overwrite any existing options to ensure that we have enough
2194 * room for the CIPSO option, the reason is that we _need_ to guarantee
2195 * that the security label is applied to the packet - we do the same
2196 * thing when using the socket options and it hasn't caused a problem,
2197 * if we need to we can always revisit this choice later */
2198
2199 len_delta = opt_len - opt->optlen;
2200 /* if we don't ensure enough headroom we could panic on the skb_push()
2201 * call below so make sure we have enough, we are also "mangling" the
2202 * packet so we should probably do a copy-on-write call anyway */
2203 ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
2204 if (ret_val < 0)
2205 return ret_val;
2206
2207 if (len_delta > 0) {
2208 /* we assume that the header + opt->optlen have already been
2209 * "pushed" in ip_options_build() or similar */
2210 iph = ip_hdr(skb);
2211 skb_push(skb, len_delta);
2212 memmove((char *)iph - len_delta, iph, iph->ihl << 2);
2213 skb_reset_network_header(skb);
2214 iph = ip_hdr(skb);
2215 } else if (len_delta < 0) {
2216 iph = ip_hdr(skb);
2217 memset(iph + 1, IPOPT_NOP, opt->optlen);
2218 } else
2219 iph = ip_hdr(skb);
2220
2221 if (opt->optlen > 0)
2222 memset(opt, 0, sizeof(*opt));
2223 opt->optlen = opt_len;
2224 opt->cipso = sizeof(struct iphdr);
2225 opt->is_changed = 1;
2226
2227 /* we have to do the following because we are being called from a
2228 * netfilter hook which means the packet already has had the header
2229 * fields populated and the checksum calculated - yes this means we
2230 * are doing more work than needed but we do it to keep the core
2231 * stack clean and tidy */
2232 memcpy(iph + 1, buf, buf_len);
2233 if (opt_len > buf_len)
2234 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
2235 if (len_delta != 0) {
2236 iph->ihl = 5 + (opt_len >> 2);
2237 iph->tot_len = htons(skb->len);
2238 }
2239 ip_send_check(iph);
2240
2241 return 0;
2242}
2243
2244/**
2245 * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
2246 * @skb: the packet
2247 *
2248 * Description:
2249 * Removes any and all CIPSO options from the given packet. Returns zero on
2250 * success, negative values on failure.
2251 *
2252 */
2253int cipso_v4_skbuff_delattr(struct sk_buff *skb)
2254{
2255 int ret_val;
2256 struct iphdr *iph;
2257 struct ip_options *opt = &IPCB(skb)->opt;
2258 unsigned char *cipso_ptr;
2259
2260 if (opt->cipso == 0)
2261 return 0;
2262
2263 /* since we are changing the packet we should make a copy */
2264 ret_val = skb_cow(skb, skb_headroom(skb));
2265 if (ret_val < 0)
2266 return ret_val;
2267
2268 /* the easiest thing to do is just replace the cipso option with noop
2269 * options since we don't change the size of the packet, although we
2270 * still need to recalculate the checksum */
2271
2272 iph = ip_hdr(skb);
2273 cipso_ptr = (unsigned char *)iph + opt->cipso;
2274 memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]);
2275 opt->cipso = 0;
2276 opt->is_changed = 1;
2277
2278 ip_send_check(iph);
2279
2280 return 0;
2281}
2282
2283/*
2284 * Setup Functions
2285 */
2286
2287/**
2288 * cipso_v4_init - Initialize the CIPSO module
2289 *
2290 * Description:
2291 * Initialize the CIPSO module and prepare it for use. Returns zero on success
2292 * and negative values on failure.
2293 *
2294 */
2295static int __init cipso_v4_init(void)
2296{
2297 int ret_val;
2298
2299 ret_val = cipso_v4_cache_init();
2300 if (ret_val != 0)
2301 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
2302 ret_val);
2303
2304 return 0;
2305}
2306
2307subsys_initcall(cipso_v4_init);
2308