~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/ipv4/cipso_ipv4.c

Version: ~ [ linux-5.2-rc1 ] ~ [ linux-5.1.2 ] ~ [ linux-5.0.16 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.43 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.119 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.176 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.179 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.139 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.67 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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. */
 61 static DEFINE_SPINLOCK(cipso_v4_doi_list_lock);
 62 static LIST_HEAD(cipso_v4_doi_list);
 63 
 64 /* Label mapping cache */
 65 int cipso_v4_cache_enabled = 1;
 66 int cipso_v4_cache_bucketsize = 10;
 67 #define CIPSO_V4_CACHE_BUCKETBITS     7
 68 #define CIPSO_V4_CACHE_BUCKETS        (1 << CIPSO_V4_CACHE_BUCKETBITS)
 69 #define CIPSO_V4_CACHE_REORDERLIMIT   10
 70 struct cipso_v4_map_cache_bkt {
 71         spinlock_t lock;
 72         u32 size;
 73         struct list_head list;
 74 };
 75 
 76 struct 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 
 87 static struct cipso_v4_map_cache_bkt *cipso_v4_cache;
 88 
 89 /* Restricted bitmap (tag #1) flags */
 90 int cipso_v4_rbm_optfmt = 0;
 91 int 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_bitmap_walk - Walk a bitmap looking for a bit
139  * @bitmap: the bitmap
140  * @bitmap_len: length in bits
141  * @offset: starting offset
142  * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit
143  *
144  * Description:
145  * Starting at @offset, walk the bitmap from left to right until either the
146  * desired bit is found or we reach the end.  Return the bit offset, -1 if
147  * not found, or -2 if error.
148  */
149 static int cipso_v4_bitmap_walk(const unsigned char *bitmap,
150                                 u32 bitmap_len,
151                                 u32 offset,
152                                 u8 state)
153 {
154         u32 bit_spot;
155         u32 byte_offset;
156         unsigned char bitmask;
157         unsigned char byte;
158 
159         /* gcc always rounds to zero when doing integer division */
160         byte_offset = offset / 8;
161         byte = bitmap[byte_offset];
162         bit_spot = offset;
163         bitmask = 0x80 >> (offset % 8);
164 
165         while (bit_spot < bitmap_len) {
166                 if ((state && (byte & bitmask) == bitmask) ||
167                     (state == 0 && (byte & bitmask) == 0))
168                         return bit_spot;
169 
170                 bit_spot++;
171                 bitmask >>= 1;
172                 if (bitmask == 0) {
173                         byte = bitmap[++byte_offset];
174                         bitmask = 0x80;
175                 }
176         }
177 
178         return -1;
179 }
180 
181 /**
182  * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap
183  * @bitmap: the bitmap
184  * @bit: the bit
185  * @state: if non-zero, set the bit (1) else clear the bit (0)
186  *
187  * Description:
188  * Set a single bit in the bitmask.  Returns zero on success, negative values
189  * on error.
190  */
191 static void cipso_v4_bitmap_setbit(unsigned char *bitmap,
192                                    u32 bit,
193                                    u8 state)
194 {
195         u32 byte_spot;
196         u8 bitmask;
197 
198         /* gcc always rounds to zero when doing integer division */
199         byte_spot = bit / 8;
200         bitmask = 0x80 >> (bit % 8);
201         if (state)
202                 bitmap[byte_spot] |= bitmask;
203         else
204                 bitmap[byte_spot] &= ~bitmask;
205 }
206 
207 /**
208  * cipso_v4_cache_entry_free - Frees a cache entry
209  * @entry: the entry to free
210  *
211  * Description:
212  * This function frees the memory associated with a cache entry including the
213  * LSM cache data if there are no longer any users, i.e. reference count == 0.
214  *
215  */
216 static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry)
217 {
218         if (entry->lsm_data)
219                 netlbl_secattr_cache_free(entry->lsm_data);
220         kfree(entry->key);
221         kfree(entry);
222 }
223 
224 /**
225  * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache
226  * @key: the hash key
227  * @key_len: the length of the key in bytes
228  *
229  * Description:
230  * The CIPSO tag hashing function.  Returns a 32-bit hash value.
231  *
232  */
233 static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len)
234 {
235         return jhash(key, key_len, 0);
236 }
237 
238 /*
239  * Label Mapping Cache Functions
240  */
241 
242 /**
243  * cipso_v4_cache_init - Initialize the CIPSO cache
244  *
245  * Description:
246  * Initializes the CIPSO label mapping cache, this function should be called
247  * before any of the other functions defined in this file.  Returns zero on
248  * success, negative values on error.
249  *
250  */
251 static int __init cipso_v4_cache_init(void)
252 {
253         u32 iter;
254 
255         cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS,
256                                  sizeof(struct cipso_v4_map_cache_bkt),
257                                  GFP_KERNEL);
258         if (!cipso_v4_cache)
259                 return -ENOMEM;
260 
261         for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
262                 spin_lock_init(&cipso_v4_cache[iter].lock);
263                 cipso_v4_cache[iter].size = 0;
264                 INIT_LIST_HEAD(&cipso_v4_cache[iter].list);
265         }
266 
267         return 0;
268 }
269 
270 /**
271  * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache
272  *
273  * Description:
274  * Invalidates and frees any entries in the CIPSO cache.  Returns zero on
275  * success and negative values on failure.
276  *
277  */
278 void cipso_v4_cache_invalidate(void)
279 {
280         struct cipso_v4_map_cache_entry *entry, *tmp_entry;
281         u32 iter;
282 
283         for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
284                 spin_lock_bh(&cipso_v4_cache[iter].lock);
285                 list_for_each_entry_safe(entry,
286                                          tmp_entry,
287                                          &cipso_v4_cache[iter].list, list) {
288                         list_del(&entry->list);
289                         cipso_v4_cache_entry_free(entry);
290                 }
291                 cipso_v4_cache[iter].size = 0;
292                 spin_unlock_bh(&cipso_v4_cache[iter].lock);
293         }
294 }
295 
296 /**
297  * cipso_v4_cache_check - Check the CIPSO cache for a label mapping
298  * @key: the buffer to check
299  * @key_len: buffer length in bytes
300  * @secattr: the security attribute struct to use
301  *
302  * Description:
303  * This function checks the cache to see if a label mapping already exists for
304  * the given key.  If there is a match then the cache is adjusted and the
305  * @secattr struct is populated with the correct LSM security attributes.  The
306  * cache is adjusted in the following manner if the entry is not already the
307  * first in the cache bucket:
308  *
309  *  1. The cache entry's activity counter is incremented
310  *  2. The previous (higher ranking) entry's activity counter is decremented
311  *  3. If the difference between the two activity counters is geater than
312  *     CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped
313  *
314  * Returns zero on success, -ENOENT for a cache miss, and other negative values
315  * on error.
316  *
317  */
318 static int cipso_v4_cache_check(const unsigned char *key,
319                                 u32 key_len,
320                                 struct netlbl_lsm_secattr *secattr)
321 {
322         u32 bkt;
323         struct cipso_v4_map_cache_entry *entry;
324         struct cipso_v4_map_cache_entry *prev_entry = NULL;
325         u32 hash;
326 
327         if (!cipso_v4_cache_enabled)
328                 return -ENOENT;
329 
330         hash = cipso_v4_map_cache_hash(key, key_len);
331         bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
332         spin_lock_bh(&cipso_v4_cache[bkt].lock);
333         list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
334                 if (entry->hash == hash &&
335                     entry->key_len == key_len &&
336                     memcmp(entry->key, key, key_len) == 0) {
337                         entry->activity += 1;
338                         atomic_inc(&entry->lsm_data->refcount);
339                         secattr->cache = entry->lsm_data;
340                         secattr->flags |= NETLBL_SECATTR_CACHE;
341                         secattr->type = NETLBL_NLTYPE_CIPSOV4;
342                         if (!prev_entry) {
343                                 spin_unlock_bh(&cipso_v4_cache[bkt].lock);
344                                 return 0;
345                         }
346 
347                         if (prev_entry->activity > 0)
348                                 prev_entry->activity -= 1;
349                         if (entry->activity > prev_entry->activity &&
350                             entry->activity - prev_entry->activity >
351                             CIPSO_V4_CACHE_REORDERLIMIT) {
352                                 __list_del(entry->list.prev, entry->list.next);
353                                 __list_add(&entry->list,
354                                            prev_entry->list.prev,
355                                            &prev_entry->list);
356                         }
357 
358                         spin_unlock_bh(&cipso_v4_cache[bkt].lock);
359                         return 0;
360                 }
361                 prev_entry = entry;
362         }
363         spin_unlock_bh(&cipso_v4_cache[bkt].lock);
364 
365         return -ENOENT;
366 }
367 
368 /**
369  * cipso_v4_cache_add - Add an entry to the CIPSO cache
370  * @skb: the packet
371  * @secattr: the packet's security attributes
372  *
373  * Description:
374  * Add a new entry into the CIPSO label mapping cache.  Add the new entry to
375  * head of the cache bucket's list, if the cache bucket is out of room remove
376  * the last entry in the list first.  It is important to note that there is
377  * currently no checking for duplicate keys.  Returns zero on success,
378  * negative values on failure.
379  *
380  */
381 int cipso_v4_cache_add(const unsigned char *cipso_ptr,
382                        const struct netlbl_lsm_secattr *secattr)
383 {
384         int ret_val = -EPERM;
385         u32 bkt;
386         struct cipso_v4_map_cache_entry *entry = NULL;
387         struct cipso_v4_map_cache_entry *old_entry = NULL;
388         u32 cipso_ptr_len;
389 
390         if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0)
391                 return 0;
392 
393         cipso_ptr_len = cipso_ptr[1];
394 
395         entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
396         if (!entry)
397                 return -ENOMEM;
398         entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC);
399         if (!entry->key) {
400                 ret_val = -ENOMEM;
401                 goto cache_add_failure;
402         }
403         entry->key_len = cipso_ptr_len;
404         entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len);
405         atomic_inc(&secattr->cache->refcount);
406         entry->lsm_data = secattr->cache;
407 
408         bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1);
409         spin_lock_bh(&cipso_v4_cache[bkt].lock);
410         if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) {
411                 list_add(&entry->list, &cipso_v4_cache[bkt].list);
412                 cipso_v4_cache[bkt].size += 1;
413         } else {
414                 old_entry = list_entry(cipso_v4_cache[bkt].list.prev,
415                                        struct cipso_v4_map_cache_entry, list);
416                 list_del(&old_entry->list);
417                 list_add(&entry->list, &cipso_v4_cache[bkt].list);
418                 cipso_v4_cache_entry_free(old_entry);
419         }
420         spin_unlock_bh(&cipso_v4_cache[bkt].lock);
421 
422         return 0;
423 
424 cache_add_failure:
425         if (entry)
426                 cipso_v4_cache_entry_free(entry);
427         return ret_val;
428 }
429 
430 /*
431  * DOI List Functions
432  */
433 
434 /**
435  * cipso_v4_doi_search - Searches for a DOI definition
436  * @doi: the DOI to search for
437  *
438  * Description:
439  * Search the DOI definition list for a DOI definition with a DOI value that
440  * matches @doi.  The caller is responsible for calling rcu_read_[un]lock().
441  * Returns a pointer to the DOI definition on success and NULL on failure.
442  */
443 static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi)
444 {
445         struct cipso_v4_doi *iter;
446 
447         list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list)
448                 if (iter->doi == doi && atomic_read(&iter->refcount))
449                         return iter;
450         return NULL;
451 }
452 
453 /**
454  * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine
455  * @doi_def: the DOI structure
456  * @audit_info: NetLabel audit information
457  *
458  * Description:
459  * The caller defines a new DOI for use by the CIPSO engine and calls this
460  * function to add it to the list of acceptable domains.  The caller must
461  * ensure that the mapping table specified in @doi_def->map meets all of the
462  * requirements of the mapping type (see cipso_ipv4.h for details).  Returns
463  * zero on success and non-zero on failure.
464  *
465  */
466 int cipso_v4_doi_add(struct cipso_v4_doi *doi_def,
467                      struct netlbl_audit *audit_info)
468 {
469         int ret_val = -EINVAL;
470         u32 iter;
471         u32 doi;
472         u32 doi_type;
473         struct audit_buffer *audit_buf;
474 
475         doi = doi_def->doi;
476         doi_type = doi_def->type;
477 
478         if (doi_def->doi == CIPSO_V4_DOI_UNKNOWN)
479                 goto doi_add_return;
480         for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) {
481                 switch (doi_def->tags[iter]) {
482                 case CIPSO_V4_TAG_RBITMAP:
483                         break;
484                 case CIPSO_V4_TAG_RANGE:
485                 case CIPSO_V4_TAG_ENUM:
486                         if (doi_def->type != CIPSO_V4_MAP_PASS)
487                                 goto doi_add_return;
488                         break;
489                 case CIPSO_V4_TAG_LOCAL:
490                         if (doi_def->type != CIPSO_V4_MAP_LOCAL)
491                                 goto doi_add_return;
492                         break;
493                 case CIPSO_V4_TAG_INVALID:
494                         if (iter == 0)
495                                 goto doi_add_return;
496                         break;
497                 default:
498                         goto doi_add_return;
499                 }
500         }
501 
502         atomic_set(&doi_def->refcount, 1);
503 
504         spin_lock(&cipso_v4_doi_list_lock);
505         if (cipso_v4_doi_search(doi_def->doi)) {
506                 spin_unlock(&cipso_v4_doi_list_lock);
507                 ret_val = -EEXIST;
508                 goto doi_add_return;
509         }
510         list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list);
511         spin_unlock(&cipso_v4_doi_list_lock);
512         ret_val = 0;
513 
514 doi_add_return:
515         audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info);
516         if (audit_buf) {
517                 const char *type_str;
518                 switch (doi_type) {
519                 case CIPSO_V4_MAP_TRANS:
520                         type_str = "trans";
521                         break;
522                 case CIPSO_V4_MAP_PASS:
523                         type_str = "pass";
524                         break;
525                 case CIPSO_V4_MAP_LOCAL:
526                         type_str = "local";
527                         break;
528                 default:
529                         type_str = "(unknown)";
530                 }
531                 audit_log_format(audit_buf,
532                                  " cipso_doi=%u cipso_type=%s res=%u",
533                                  doi, type_str, ret_val == 0 ? 1 : 0);
534                 audit_log_end(audit_buf);
535         }
536 
537         return ret_val;
538 }
539 
540 /**
541  * cipso_v4_doi_free - Frees a DOI definition
542  * @doi_def: the DOI definition
543  *
544  * Description:
545  * This function frees all of the memory associated with a DOI definition.
546  *
547  */
548 void cipso_v4_doi_free(struct cipso_v4_doi *doi_def)
549 {
550         if (!doi_def)
551                 return;
552 
553         switch (doi_def->type) {
554         case CIPSO_V4_MAP_TRANS:
555                 kfree(doi_def->map.std->lvl.cipso);
556                 kfree(doi_def->map.std->lvl.local);
557                 kfree(doi_def->map.std->cat.cipso);
558                 kfree(doi_def->map.std->cat.local);
559                 break;
560         }
561         kfree(doi_def);
562 }
563 
564 /**
565  * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer
566  * @entry: the entry's RCU field
567  *
568  * Description:
569  * This function is designed to be used as a callback to the call_rcu()
570  * function so that the memory allocated to the DOI definition can be released
571  * safely.
572  *
573  */
574 static void cipso_v4_doi_free_rcu(struct rcu_head *entry)
575 {
576         struct cipso_v4_doi *doi_def;
577 
578         doi_def = container_of(entry, struct cipso_v4_doi, rcu);
579         cipso_v4_doi_free(doi_def);
580 }
581 
582 /**
583  * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine
584  * @doi: the DOI value
585  * @audit_secid: the LSM secid to use in the audit message
586  *
587  * Description:
588  * Removes a DOI definition from the CIPSO engine.  The NetLabel routines will
589  * be called to release their own LSM domain mappings as well as our own
590  * domain list.  Returns zero on success and negative values on failure.
591  *
592  */
593 int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info)
594 {
595         int ret_val;
596         struct cipso_v4_doi *doi_def;
597         struct audit_buffer *audit_buf;
598 
599         spin_lock(&cipso_v4_doi_list_lock);
600         doi_def = cipso_v4_doi_search(doi);
601         if (!doi_def) {
602                 spin_unlock(&cipso_v4_doi_list_lock);
603                 ret_val = -ENOENT;
604                 goto doi_remove_return;
605         }
606         if (!atomic_dec_and_test(&doi_def->refcount)) {
607                 spin_unlock(&cipso_v4_doi_list_lock);
608                 ret_val = -EBUSY;
609                 goto doi_remove_return;
610         }
611         list_del_rcu(&doi_def->list);
612         spin_unlock(&cipso_v4_doi_list_lock);
613 
614         cipso_v4_cache_invalidate();
615         call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
616         ret_val = 0;
617 
618 doi_remove_return:
619         audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info);
620         if (audit_buf) {
621                 audit_log_format(audit_buf,
622                                  " cipso_doi=%u res=%u",
623                                  doi, ret_val == 0 ? 1 : 0);
624                 audit_log_end(audit_buf);
625         }
626 
627         return ret_val;
628 }
629 
630 /**
631  * cipso_v4_doi_getdef - Returns a reference to a valid DOI definition
632  * @doi: the DOI value
633  *
634  * Description:
635  * Searches for a valid DOI definition and if one is found it is returned to
636  * the caller.  Otherwise NULL is returned.  The caller must ensure that
637  * rcu_read_lock() is held while accessing the returned definition and the DOI
638  * definition reference count is decremented when the caller is done.
639  *
640  */
641 struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
642 {
643         struct cipso_v4_doi *doi_def;
644 
645         rcu_read_lock();
646         doi_def = cipso_v4_doi_search(doi);
647         if (!doi_def)
648                 goto doi_getdef_return;
649         if (!atomic_inc_not_zero(&doi_def->refcount))
650                 doi_def = NULL;
651 
652 doi_getdef_return:
653         rcu_read_unlock();
654         return doi_def;
655 }
656 
657 /**
658  * cipso_v4_doi_putdef - Releases a reference for the given DOI definition
659  * @doi_def: the DOI definition
660  *
661  * Description:
662  * Releases a DOI definition reference obtained from cipso_v4_doi_getdef().
663  *
664  */
665 void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def)
666 {
667         if (!doi_def)
668                 return;
669 
670         if (!atomic_dec_and_test(&doi_def->refcount))
671                 return;
672         spin_lock(&cipso_v4_doi_list_lock);
673         list_del_rcu(&doi_def->list);
674         spin_unlock(&cipso_v4_doi_list_lock);
675 
676         cipso_v4_cache_invalidate();
677         call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
678 }
679 
680 /**
681  * cipso_v4_doi_walk - Iterate through the DOI definitions
682  * @skip_cnt: skip past this number of DOI definitions, updated
683  * @callback: callback for each DOI definition
684  * @cb_arg: argument for the callback function
685  *
686  * Description:
687  * Iterate over the DOI definition list, skipping the first @skip_cnt entries.
688  * For each entry call @callback, if @callback returns a negative value stop
689  * 'walking' through the list and return.  Updates the value in @skip_cnt upon
690  * return.  Returns zero on success, negative values on failure.
691  *
692  */
693 int cipso_v4_doi_walk(u32 *skip_cnt,
694                      int (*callback) (struct cipso_v4_doi *doi_def, void *arg),
695                      void *cb_arg)
696 {
697         int ret_val = -ENOENT;
698         u32 doi_cnt = 0;
699         struct cipso_v4_doi *iter_doi;
700 
701         rcu_read_lock();
702         list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
703                 if (atomic_read(&iter_doi->refcount) > 0) {
704                         if (doi_cnt++ < *skip_cnt)
705                                 continue;
706                         ret_val = callback(iter_doi, cb_arg);
707                         if (ret_val < 0) {
708                                 doi_cnt--;
709                                 goto doi_walk_return;
710                         }
711                 }
712 
713 doi_walk_return:
714         rcu_read_unlock();
715         *skip_cnt = doi_cnt;
716         return ret_val;
717 }
718 
719 /*
720  * Label Mapping Functions
721  */
722 
723 /**
724  * cipso_v4_map_lvl_valid - Checks to see if the given level is understood
725  * @doi_def: the DOI definition
726  * @level: the level to check
727  *
728  * Description:
729  * Checks the given level against the given DOI definition and returns a
730  * negative value if the level does not have a valid mapping and a zero value
731  * if the level is defined by the DOI.
732  *
733  */
734 static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
735 {
736         switch (doi_def->type) {
737         case CIPSO_V4_MAP_PASS:
738                 return 0;
739         case CIPSO_V4_MAP_TRANS:
740                 if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL)
741                         return 0;
742                 break;
743         }
744 
745         return -EFAULT;
746 }
747 
748 /**
749  * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
750  * @doi_def: the DOI definition
751  * @host_lvl: the host MLS level
752  * @net_lvl: the network/CIPSO MLS level
753  *
754  * Description:
755  * Perform a label mapping to translate a local MLS level to the correct
756  * CIPSO level using the given DOI definition.  Returns zero on success,
757  * negative values otherwise.
758  *
759  */
760 static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
761                                  u32 host_lvl,
762                                  u32 *net_lvl)
763 {
764         switch (doi_def->type) {
765         case CIPSO_V4_MAP_PASS:
766                 *net_lvl = host_lvl;
767                 return 0;
768         case CIPSO_V4_MAP_TRANS:
769                 if (host_lvl < doi_def->map.std->lvl.local_size &&
770                     doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) {
771                         *net_lvl = doi_def->map.std->lvl.local[host_lvl];
772                         return 0;
773                 }
774                 return -EPERM;
775         }
776 
777         return -EINVAL;
778 }
779 
780 /**
781  * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
782  * @doi_def: the DOI definition
783  * @net_lvl: the network/CIPSO MLS level
784  * @host_lvl: the host MLS level
785  *
786  * Description:
787  * Perform a label mapping to translate a CIPSO level to the correct local MLS
788  * level using the given DOI definition.  Returns zero on success, negative
789  * values otherwise.
790  *
791  */
792 static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
793                                  u32 net_lvl,
794                                  u32 *host_lvl)
795 {
796         struct cipso_v4_std_map_tbl *map_tbl;
797 
798         switch (doi_def->type) {
799         case CIPSO_V4_MAP_PASS:
800                 *host_lvl = net_lvl;
801                 return 0;
802         case CIPSO_V4_MAP_TRANS:
803                 map_tbl = doi_def->map.std;
804                 if (net_lvl < map_tbl->lvl.cipso_size &&
805                     map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
806                         *host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
807                         return 0;
808                 }
809                 return -EPERM;
810         }
811 
812         return -EINVAL;
813 }
814 
815 /**
816  * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
817  * @doi_def: the DOI definition
818  * @bitmap: category bitmap
819  * @bitmap_len: bitmap length in bytes
820  *
821  * Description:
822  * Checks the given category bitmap against the given DOI definition and
823  * returns a negative value if any of the categories in the bitmap do not have
824  * a valid mapping and a zero value if all of the categories are valid.
825  *
826  */
827 static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
828                                       const unsigned char *bitmap,
829                                       u32 bitmap_len)
830 {
831         int cat = -1;
832         u32 bitmap_len_bits = bitmap_len * 8;
833         u32 cipso_cat_size;
834         u32 *cipso_array;
835 
836         switch (doi_def->type) {
837         case CIPSO_V4_MAP_PASS:
838                 return 0;
839         case CIPSO_V4_MAP_TRANS:
840                 cipso_cat_size = doi_def->map.std->cat.cipso_size;
841                 cipso_array = doi_def->map.std->cat.cipso;
842                 for (;;) {
843                         cat = cipso_v4_bitmap_walk(bitmap,
844                                                    bitmap_len_bits,
845                                                    cat + 1,
846                                                    1);
847                         if (cat < 0)
848                                 break;
849                         if (cat >= cipso_cat_size ||
850                             cipso_array[cat] >= CIPSO_V4_INV_CAT)
851                                 return -EFAULT;
852                 }
853 
854                 if (cat == -1)
855                         return 0;
856                 break;
857         }
858 
859         return -EFAULT;
860 }
861 
862 /**
863  * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
864  * @doi_def: the DOI definition
865  * @secattr: the security attributes
866  * @net_cat: the zero'd out category bitmap in network/CIPSO format
867  * @net_cat_len: the length of the CIPSO bitmap in bytes
868  *
869  * Description:
870  * Perform a label mapping to translate a local MLS category bitmap to the
871  * correct CIPSO bitmap using the given DOI definition.  Returns the minimum
872  * size in bytes of the network bitmap on success, negative values otherwise.
873  *
874  */
875 static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
876                                      const struct netlbl_lsm_secattr *secattr,
877                                      unsigned char *net_cat,
878                                      u32 net_cat_len)
879 {
880         int host_spot = -1;
881         u32 net_spot = CIPSO_V4_INV_CAT;
882         u32 net_spot_max = 0;
883         u32 net_clen_bits = net_cat_len * 8;
884         u32 host_cat_size = 0;
885         u32 *host_cat_array = NULL;
886 
887         if (doi_def->type == CIPSO_V4_MAP_TRANS) {
888                 host_cat_size = doi_def->map.std->cat.local_size;
889                 host_cat_array = doi_def->map.std->cat.local;
890         }
891 
892         for (;;) {
893                 host_spot = netlbl_catmap_walk(secattr->attr.mls.cat,
894                                                host_spot + 1);
895                 if (host_spot < 0)
896                         break;
897 
898                 switch (doi_def->type) {
899                 case CIPSO_V4_MAP_PASS:
900                         net_spot = host_spot;
901                         break;
902                 case CIPSO_V4_MAP_TRANS:
903                         if (host_spot >= host_cat_size)
904                                 return -EPERM;
905                         net_spot = host_cat_array[host_spot];
906                         if (net_spot >= CIPSO_V4_INV_CAT)
907                                 return -EPERM;
908                         break;
909                 }
910                 if (net_spot >= net_clen_bits)
911                         return -ENOSPC;
912                 cipso_v4_bitmap_setbit(net_cat, net_spot, 1);
913 
914                 if (net_spot > net_spot_max)
915                         net_spot_max = net_spot;
916         }
917 
918         if (++net_spot_max % 8)
919                 return net_spot_max / 8 + 1;
920         return net_spot_max / 8;
921 }
922 
923 /**
924  * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host
925  * @doi_def: the DOI definition
926  * @net_cat: the category bitmap in network/CIPSO format
927  * @net_cat_len: the length of the CIPSO bitmap in bytes
928  * @secattr: the security attributes
929  *
930  * Description:
931  * Perform a label mapping to translate a CIPSO bitmap to the correct local
932  * MLS category bitmap using the given DOI definition.  Returns zero on
933  * success, negative values on failure.
934  *
935  */
936 static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
937                                      const unsigned char *net_cat,
938                                      u32 net_cat_len,
939                                      struct netlbl_lsm_secattr *secattr)
940 {
941         int ret_val;
942         int net_spot = -1;
943         u32 host_spot = CIPSO_V4_INV_CAT;
944         u32 net_clen_bits = net_cat_len * 8;
945         u32 net_cat_size = 0;
946         u32 *net_cat_array = NULL;
947 
948         if (doi_def->type == CIPSO_V4_MAP_TRANS) {
949                 net_cat_size = doi_def->map.std->cat.cipso_size;
950                 net_cat_array = doi_def->map.std->cat.cipso;
951         }
952 
953         for (;;) {
954                 net_spot = cipso_v4_bitmap_walk(net_cat,
955                                                 net_clen_bits,
956                                                 net_spot + 1,
957                                                 1);
958                 if (net_spot < 0) {
959                         if (net_spot == -2)
960                                 return -EFAULT;
961                         return 0;
962                 }
963 
964                 switch (doi_def->type) {
965                 case CIPSO_V4_MAP_PASS:
966                         host_spot = net_spot;
967                         break;
968                 case CIPSO_V4_MAP_TRANS:
969                         if (net_spot >= net_cat_size)
970                                 return -EPERM;
971                         host_spot = net_cat_array[net_spot];
972                         if (host_spot >= CIPSO_V4_INV_CAT)
973                                 return -EPERM;
974                         break;
975                 }
976                 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
977                                                        host_spot,
978                                                        GFP_ATOMIC);
979                 if (ret_val != 0)
980                         return ret_val;
981         }
982 
983         return -EINVAL;
984 }
985 
986 /**
987  * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid
988  * @doi_def: the DOI definition
989  * @enumcat: category list
990  * @enumcat_len: length of the category list in bytes
991  *
992  * Description:
993  * Checks the given categories against the given DOI definition and returns a
994  * negative value if any of the categories do not have a valid mapping and a
995  * zero value if all of the categories are valid.
996  *
997  */
998 static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def,
999                                        const unsigned char *enumcat,
1000                                        u32 enumcat_len)
1001 {
1002         u16 cat;
1003         int cat_prev = -1;
1004         u32 iter;
1005 
1006         if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01)
1007                 return -EFAULT;
1008 
1009         for (iter = 0; iter < enumcat_len; iter += 2) {
1010                 cat = get_unaligned_be16(&enumcat[iter]);
1011                 if (cat <= cat_prev)
1012                         return -EFAULT;
1013                 cat_prev = cat;
1014         }
1015 
1016         return 0;
1017 }
1018 
1019 /**
1020  * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network
1021  * @doi_def: the DOI definition
1022  * @secattr: the security attributes
1023  * @net_cat: the zero'd out category list in network/CIPSO format
1024  * @net_cat_len: the length of the CIPSO category list in bytes
1025  *
1026  * Description:
1027  * Perform a label mapping to translate a local MLS category bitmap to the
1028  * correct CIPSO category list using the given DOI definition.   Returns the
1029  * size in bytes of the network category bitmap on success, negative values
1030  * otherwise.
1031  *
1032  */
1033 static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def,
1034                                       const struct netlbl_lsm_secattr *secattr,
1035                                       unsigned char *net_cat,
1036                                       u32 net_cat_len)
1037 {
1038         int cat = -1;
1039         u32 cat_iter = 0;
1040 
1041         for (;;) {
1042                 cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1);
1043                 if (cat < 0)
1044                         break;
1045                 if ((cat_iter + 2) > net_cat_len)
1046                         return -ENOSPC;
1047 
1048                 *((__be16 *)&net_cat[cat_iter]) = htons(cat);
1049                 cat_iter += 2;
1050         }
1051 
1052         return cat_iter;
1053 }
1054 
1055 /**
1056  * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host
1057  * @doi_def: the DOI definition
1058  * @net_cat: the category list in network/CIPSO format
1059  * @net_cat_len: the length of the CIPSO bitmap in bytes
1060  * @secattr: the security attributes
1061  *
1062  * Description:
1063  * Perform a label mapping to translate a CIPSO category list to the correct
1064  * local MLS category bitmap using the given DOI definition.  Returns zero on
1065  * success, negative values on failure.
1066  *
1067  */
1068 static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def,
1069                                       const unsigned char *net_cat,
1070                                       u32 net_cat_len,
1071                                       struct netlbl_lsm_secattr *secattr)
1072 {
1073         int ret_val;
1074         u32 iter;
1075 
1076         for (iter = 0; iter < net_cat_len; iter += 2) {
1077                 ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
1078                                              get_unaligned_be16(&net_cat[iter]),
1079                                              GFP_ATOMIC);
1080                 if (ret_val != 0)
1081                         return ret_val;
1082         }
1083 
1084         return 0;
1085 }
1086 
1087 /**
1088  * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid
1089  * @doi_def: the DOI definition
1090  * @rngcat: category list
1091  * @rngcat_len: length of the category list in bytes
1092  *
1093  * Description:
1094  * Checks the given categories against the given DOI definition and returns a
1095  * negative value if any of the categories do not have a valid mapping and a
1096  * zero value if all of the categories are valid.
1097  *
1098  */
1099 static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def,
1100                                       const unsigned char *rngcat,
1101                                       u32 rngcat_len)
1102 {
1103         u16 cat_high;
1104         u16 cat_low;
1105         u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1;
1106         u32 iter;
1107 
1108         if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01)
1109                 return -EFAULT;
1110 
1111         for (iter = 0; iter < rngcat_len; iter += 4) {
1112                 cat_high = get_unaligned_be16(&rngcat[iter]);
1113                 if ((iter + 4) <= rngcat_len)
1114                         cat_low = get_unaligned_be16(&rngcat[iter + 2]);
1115                 else
1116                         cat_low = 0;
1117 
1118                 if (cat_high > cat_prev)
1119                         return -EFAULT;
1120 
1121                 cat_prev = cat_low;
1122         }
1123 
1124         return 0;
1125 }
1126 
1127 /**
1128  * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network
1129  * @doi_def: the DOI definition
1130  * @secattr: the security attributes
1131  * @net_cat: the zero'd out category list in network/CIPSO format
1132  * @net_cat_len: the length of the CIPSO category list in bytes
1133  *
1134  * Description:
1135  * Perform a label mapping to translate a local MLS category bitmap to the
1136  * correct CIPSO category list using the given DOI definition.   Returns the
1137  * size in bytes of the network category bitmap on success, negative values
1138  * otherwise.
1139  *
1140  */
1141 static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def,
1142                                      const struct netlbl_lsm_secattr *secattr,
1143                                      unsigned char *net_cat,
1144                                      u32 net_cat_len)
1145 {
1146         int iter = -1;
1147         u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2];
1148         u32 array_cnt = 0;
1149         u32 cat_size = 0;
1150 
1151         /* make sure we don't overflow the 'array[]' variable */
1152         if (net_cat_len >
1153             (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN))
1154                 return -ENOSPC;
1155 
1156         for (;;) {
1157                 iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1);
1158                 if (iter < 0)
1159                         break;
1160                 cat_size += (iter == 0 ? 0 : sizeof(u16));
1161                 if (cat_size > net_cat_len)
1162                         return -ENOSPC;
1163                 array[array_cnt++] = iter;
1164 
1165                 iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter);
1166                 if (iter < 0)
1167                         return -EFAULT;
1168                 cat_size += sizeof(u16);
1169                 if (cat_size > net_cat_len)
1170                         return -ENOSPC;
1171                 array[array_cnt++] = iter;
1172         }
1173 
1174         for (iter = 0; array_cnt > 0;) {
1175                 *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]);
1176                 iter += 2;
1177                 array_cnt--;
1178                 if (array[array_cnt] != 0) {
1179                         *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]);
1180                         iter += 2;
1181                 }
1182         }
1183 
1184         return cat_size;
1185 }
1186 
1187 /**
1188  * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host
1189  * @doi_def: the DOI definition
1190  * @net_cat: the category list in network/CIPSO format
1191  * @net_cat_len: the length of the CIPSO bitmap in bytes
1192  * @secattr: the security attributes
1193  *
1194  * Description:
1195  * Perform a label mapping to translate a CIPSO category list to the correct
1196  * local MLS category bitmap using the given DOI definition.  Returns zero on
1197  * success, negative values on failure.
1198  *
1199  */
1200 static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def,
1201                                      const unsigned char *net_cat,
1202                                      u32 net_cat_len,
1203                                      struct netlbl_lsm_secattr *secattr)
1204 {
1205         int ret_val;
1206         u32 net_iter;
1207         u16 cat_low;
1208         u16 cat_high;
1209 
1210         for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) {
1211                 cat_high = get_unaligned_be16(&net_cat[net_iter]);
1212                 if ((net_iter + 4) <= net_cat_len)
1213                         cat_low = get_unaligned_be16(&net_cat[net_iter + 2]);
1214                 else
1215                         cat_low = 0;
1216 
1217                 ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat,
1218                                                cat_low,
1219                                                cat_high,
1220                                                GFP_ATOMIC);
1221                 if (ret_val != 0)
1222                         return ret_val;
1223         }
1224 
1225         return 0;
1226 }
1227 
1228 /*
1229  * Protocol Handling Functions
1230  */
1231 
1232 /**
1233  * cipso_v4_gentag_hdr - Generate a CIPSO option header
1234  * @doi_def: the DOI definition
1235  * @len: the total tag length in bytes, not including this header
1236  * @buf: the CIPSO option buffer
1237  *
1238  * Description:
1239  * Write a CIPSO header into the beginning of @buffer.
1240  *
1241  */
1242 static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
1243                                 unsigned char *buf,
1244                                 u32 len)
1245 {
1246         buf[0] = IPOPT_CIPSO;
1247         buf[1] = CIPSO_V4_HDR_LEN + len;
1248         *(__be32 *)&buf[2] = htonl(doi_def->doi);
1249 }
1250 
1251 /**
1252  * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1)
1253  * @doi_def: the DOI definition
1254  * @secattr: the security attributes
1255  * @buffer: the option buffer
1256  * @buffer_len: length of buffer in bytes
1257  *
1258  * Description:
1259  * Generate a CIPSO option using the restricted bitmap tag, tag type #1.  The
1260  * actual buffer length may be larger than the indicated size due to
1261  * translation between host and network category bitmaps.  Returns the size of
1262  * the tag on success, negative values on failure.
1263  *
1264  */
1265 static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
1266                                const struct netlbl_lsm_secattr *secattr,
1267                                unsigned char *buffer,
1268                                u32 buffer_len)
1269 {
1270         int ret_val;
1271         u32 tag_len;
1272         u32 level;
1273 
1274         if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
1275                 return -EPERM;
1276 
1277         ret_val = cipso_v4_map_lvl_hton(doi_def,
1278                                         secattr->attr.mls.lvl,
1279                                         &level);
1280         if (ret_val != 0)
1281                 return ret_val;
1282 
1283         if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1284                 ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
1285                                                     secattr,
1286                                                     &buffer[4],
1287                                                     buffer_len - 4);
1288                 if (ret_val < 0)
1289                         return ret_val;
1290 
1291                 /* This will send packets using the "optimized" format when
1292                  * possible as specified in  section 3.4.2.6 of the
1293                  * CIPSO draft. */
1294                 if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10)
1295                         tag_len = 14;
1296                 else
1297                         tag_len = 4 + ret_val;
1298         } else
1299                 tag_len = 4;
1300 
1301         buffer[0] = CIPSO_V4_TAG_RBITMAP;
1302         buffer[1] = tag_len;
1303         buffer[3] = level;
1304 
1305         return tag_len;
1306 }
1307 
1308 /**
1309  * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag
1310  * @doi_def: the DOI definition
1311  * @tag: the CIPSO tag
1312  * @secattr: the security attributes
1313  *
1314  * Description:
1315  * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security
1316  * attributes in @secattr.  Return zero on success, negatives values on
1317  * failure.
1318  *
1319  */
1320 static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
1321                                  const unsigned char *tag,
1322                                  struct netlbl_lsm_secattr *secattr)
1323 {
1324         int ret_val;
1325         u8 tag_len = tag[1];
1326         u32 level;
1327 
1328         ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1329         if (ret_val != 0)
1330                 return ret_val;
1331         secattr->attr.mls.lvl = level;
1332         secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1333 
1334         if (tag_len > 4) {
1335                 ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
1336                                                     &tag[4],
1337                                                     tag_len - 4,
1338                                                     secattr);
1339                 if (ret_val != 0) {
1340                         netlbl_catmap_free(secattr->attr.mls.cat);
1341                         return ret_val;
1342                 }
1343 
1344                 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1345         }
1346 
1347         return 0;
1348 }
1349 
1350 /**
1351  * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2)
1352  * @doi_def: the DOI definition
1353  * @secattr: the security attributes
1354  * @buffer: the option buffer
1355  * @buffer_len: length of buffer in bytes
1356  *
1357  * Description:
1358  * Generate a CIPSO option using the enumerated tag, tag type #2.  Returns the
1359  * size of the tag on success, negative values on failure.
1360  *
1361  */
1362 static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def,
1363                                 const struct netlbl_lsm_secattr *secattr,
1364                                 unsigned char *buffer,
1365                                 u32 buffer_len)
1366 {
1367         int ret_val;
1368         u32 tag_len;
1369         u32 level;
1370 
1371         if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1372                 return -EPERM;
1373 
1374         ret_val = cipso_v4_map_lvl_hton(doi_def,
1375                                         secattr->attr.mls.lvl,
1376                                         &level);
1377         if (ret_val != 0)
1378                 return ret_val;
1379 
1380         if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1381                 ret_val = cipso_v4_map_cat_enum_hton(doi_def,
1382                                                      secattr,
1383                                                      &buffer[4],
1384                                                      buffer_len - 4);
1385                 if (ret_val < 0)
1386                         return ret_val;
1387 
1388                 tag_len = 4 + ret_val;
1389         } else
1390                 tag_len = 4;
1391 
1392         buffer[0] = CIPSO_V4_TAG_ENUM;
1393         buffer[1] = tag_len;
1394         buffer[3] = level;
1395 
1396         return tag_len;
1397 }
1398 
1399 /**
1400  * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag
1401  * @doi_def: the DOI definition
1402  * @tag: the CIPSO tag
1403  * @secattr: the security attributes
1404  *
1405  * Description:
1406  * Parse a CIPSO enumerated tag (tag type #2) and return the security
1407  * attributes in @secattr.  Return zero on success, negatives values on
1408  * failure.
1409  *
1410  */
1411 static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def,
1412                                   const unsigned char *tag,
1413                                   struct netlbl_lsm_secattr *secattr)
1414 {
1415         int ret_val;
1416         u8 tag_len = tag[1];
1417         u32 level;
1418 
1419         ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1420         if (ret_val != 0)
1421                 return ret_val;
1422         secattr->attr.mls.lvl = level;
1423         secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1424 
1425         if (tag_len > 4) {
1426                 ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
1427                                                      &tag[4],
1428                                                      tag_len - 4,
1429                                                      secattr);
1430                 if (ret_val != 0) {
1431                         netlbl_catmap_free(secattr->attr.mls.cat);
1432                         return ret_val;
1433                 }
1434 
1435                 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1436         }
1437 
1438         return 0;
1439 }
1440 
1441 /**
1442  * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5)
1443  * @doi_def: the DOI definition
1444  * @secattr: the security attributes
1445  * @buffer: the option buffer
1446  * @buffer_len: length of buffer in bytes
1447  *
1448  * Description:
1449  * Generate a CIPSO option using the ranged tag, tag type #5.  Returns the
1450  * size of the tag on success, negative values on failure.
1451  *
1452  */
1453 static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def,
1454                                const struct netlbl_lsm_secattr *secattr,
1455                                unsigned char *buffer,
1456                                u32 buffer_len)
1457 {
1458         int ret_val;
1459         u32 tag_len;
1460         u32 level;
1461 
1462         if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
1463                 return -EPERM;
1464 
1465         ret_val = cipso_v4_map_lvl_hton(doi_def,
1466                                         secattr->attr.mls.lvl,
1467                                         &level);
1468         if (ret_val != 0)
1469                 return ret_val;
1470 
1471         if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
1472                 ret_val = cipso_v4_map_cat_rng_hton(doi_def,
1473                                                     secattr,
1474                                                     &buffer[4],
1475                                                     buffer_len - 4);
1476                 if (ret_val < 0)
1477                         return ret_val;
1478 
1479                 tag_len = 4 + ret_val;
1480         } else
1481                 tag_len = 4;
1482 
1483         buffer[0] = CIPSO_V4_TAG_RANGE;
1484         buffer[1] = tag_len;
1485         buffer[3] = level;
1486 
1487         return tag_len;
1488 }
1489 
1490 /**
1491  * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag
1492  * @doi_def: the DOI definition
1493  * @tag: the CIPSO tag
1494  * @secattr: the security attributes
1495  *
1496  * Description:
1497  * Parse a CIPSO ranged tag (tag type #5) and return the security attributes
1498  * in @secattr.  Return zero on success, negatives values on failure.
1499  *
1500  */
1501 static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def,
1502                                  const unsigned char *tag,
1503                                  struct netlbl_lsm_secattr *secattr)
1504 {
1505         int ret_val;
1506         u8 tag_len = tag[1];
1507         u32 level;
1508 
1509         ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
1510         if (ret_val != 0)
1511                 return ret_val;
1512         secattr->attr.mls.lvl = level;
1513         secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1514 
1515         if (tag_len > 4) {
1516                 ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
1517                                                     &tag[4],
1518                                                     tag_len - 4,
1519                                                     secattr);
1520                 if (ret_val != 0) {
1521                         netlbl_catmap_free(secattr->attr.mls.cat);
1522                         return ret_val;
1523                 }
1524 
1525                 secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1526         }
1527 
1528         return 0;
1529 }
1530 
1531 /**
1532  * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard)
1533  * @doi_def: the DOI definition
1534  * @secattr: the security attributes
1535  * @buffer: the option buffer
1536  * @buffer_len: length of buffer in bytes
1537  *
1538  * Description:
1539  * Generate a CIPSO option using the local tag.  Returns the size of the tag
1540  * on success, negative values on failure.
1541  *
1542  */
1543 static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
1544                                const struct netlbl_lsm_secattr *secattr,
1545                                unsigned char *buffer,
1546                                u32 buffer_len)
1547 {
1548         if (!(secattr->flags & NETLBL_SECATTR_SECID))
1549                 return -EPERM;
1550 
1551         buffer[0] = CIPSO_V4_TAG_LOCAL;
1552         buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
1553         *(u32 *)&buffer[2] = secattr->attr.secid;
1554 
1555         return CIPSO_V4_TAG_LOC_BLEN;
1556 }
1557 
1558 /**
1559  * cipso_v4_parsetag_loc - Parse a CIPSO local tag
1560  * @doi_def: the DOI definition
1561  * @tag: the CIPSO tag
1562  * @secattr: the security attributes
1563  *
1564  * Description:
1565  * Parse a CIPSO local tag and return the security attributes in @secattr.
1566  * Return zero on success, negatives values on failure.
1567  *
1568  */
1569 static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
1570                                  const unsigned char *tag,
1571                                  struct netlbl_lsm_secattr *secattr)
1572 {
1573         secattr->attr.secid = *(u32 *)&tag[2];
1574         secattr->flags |= NETLBL_SECATTR_SECID;
1575 
1576         return 0;
1577 }
1578 
1579 /**
1580  * cipso_v4_optptr - Find the CIPSO option in the packet
1581  * @skb: the packet
1582  *
1583  * Description:
1584  * Parse the packet's IP header looking for a CIPSO option.  Returns a pointer
1585  * to the start of the CIPSO option on success, NULL if one if not found.
1586  *
1587  */
1588 unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
1589 {
1590         const struct iphdr *iph = ip_hdr(skb);
1591         unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]);
1592         int optlen;
1593         int taglen;
1594 
1595         for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) {
1596                 if (optptr[0] == IPOPT_CIPSO)
1597                         return optptr;
1598                 taglen = optptr[1];
1599                 optlen -= taglen;
1600                 optptr += taglen;
1601         }
1602 
1603         return NULL;
1604 }
1605 
1606 /**
1607  * cipso_v4_validate - Validate a CIPSO option
1608  * @option: the start of the option, on error it is set to point to the error
1609  *
1610  * Description:
1611  * This routine is called to validate a CIPSO option, it checks all of the
1612  * fields to ensure that they are at least valid, see the draft snippet below
1613  * for details.  If the option is valid then a zero value is returned and
1614  * the value of @option is unchanged.  If the option is invalid then a
1615  * non-zero value is returned and @option is adjusted to point to the
1616  * offending portion of the option.  From the IETF draft ...
1617  *
1618  *  "If any field within the CIPSO options, such as the DOI identifier, is not
1619  *   recognized the IP datagram is discarded and an ICMP 'parameter problem'
1620  *   (type 12) is generated and returned.  The ICMP code field is set to 'bad
1621  *   parameter' (code 0) and the pointer is set to the start of the CIPSO field
1622  *   that is unrecognized."
1623  *
1624  */
1625 int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
1626 {
1627         unsigned char *opt = *option;
1628         unsigned char *tag;
1629         unsigned char opt_iter;
1630         unsigned char err_offset = 0;
1631         u8 opt_len;
1632         u8 tag_len;
1633         struct cipso_v4_doi *doi_def = NULL;
1634         u32 tag_iter;
1635 
1636         /* caller already checks for length values that are too large */
1637         opt_len = opt[1];
1638         if (opt_len < 8) {
1639                 err_offset = 1;
1640                 goto validate_return;
1641         }
1642 
1643         rcu_read_lock();
1644         doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2]));
1645         if (!doi_def) {
1646                 err_offset = 2;
1647                 goto validate_return_locked;
1648         }
1649 
1650         opt_iter = CIPSO_V4_HDR_LEN;
1651         tag = opt + opt_iter;
1652         while (opt_iter < opt_len) {
1653                 for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
1654                         if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
1655                             ++tag_iter == CIPSO_V4_TAG_MAXCNT) {
1656                                 err_offset = opt_iter;
1657                                 goto validate_return_locked;
1658                         }
1659 
1660                 tag_len = tag[1];
1661                 if (tag_len > (opt_len - opt_iter)) {
1662                         err_offset = opt_iter + 1;
1663                         goto validate_return_locked;
1664                 }
1665 
1666                 switch (tag[0]) {
1667                 case CIPSO_V4_TAG_RBITMAP:
1668                         if (tag_len < CIPSO_V4_TAG_RBM_BLEN) {
1669                                 err_offset = opt_iter + 1;
1670                                 goto validate_return_locked;
1671                         }
1672 
1673                         /* We are already going to do all the verification
1674                          * necessary at the socket layer so from our point of
1675                          * view it is safe to turn these checks off (and less
1676                          * work), however, the CIPSO draft says we should do
1677                          * all the CIPSO validations here but it doesn't
1678                          * really specify _exactly_ what we need to validate
1679                          * ... so, just make it a sysctl tunable. */
1680                         if (cipso_v4_rbm_strictvalid) {
1681                                 if (cipso_v4_map_lvl_valid(doi_def,
1682                                                            tag[3]) < 0) {
1683                                         err_offset = opt_iter + 3;
1684                                         goto validate_return_locked;
1685                                 }
1686                                 if (tag_len > CIPSO_V4_TAG_RBM_BLEN &&
1687                                     cipso_v4_map_cat_rbm_valid(doi_def,
1688                                                             &tag[4],
1689                                                             tag_len - 4) < 0) {
1690                                         err_offset = opt_iter + 4;
1691                                         goto validate_return_locked;
1692                                 }
1693                         }
1694                         break;
1695                 case CIPSO_V4_TAG_ENUM:
1696                         if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) {
1697                                 err_offset = opt_iter + 1;
1698                                 goto validate_return_locked;
1699                         }
1700 
1701                         if (cipso_v4_map_lvl_valid(doi_def,
1702                                                    tag[3]) < 0) {
1703                                 err_offset = opt_iter + 3;
1704                                 goto validate_return_locked;
1705                         }
1706                         if (tag_len > CIPSO_V4_TAG_ENUM_BLEN &&
1707                             cipso_v4_map_cat_enum_valid(doi_def,
1708                                                         &tag[4],
1709                                                         tag_len - 4) < 0) {
1710                                 err_offset = opt_iter + 4;
1711                                 goto validate_return_locked;
1712                         }
1713                         break;
1714                 case CIPSO_V4_TAG_RANGE:
1715                         if (tag_len < CIPSO_V4_TAG_RNG_BLEN) {
1716                                 err_offset = opt_iter + 1;
1717                                 goto validate_return_locked;
1718                         }
1719 
1720                         if (cipso_v4_map_lvl_valid(doi_def,
1721                                                    tag[3]) < 0) {
1722                                 err_offset = opt_iter + 3;
1723                                 goto validate_return_locked;
1724                         }
1725                         if (tag_len > CIPSO_V4_TAG_RNG_BLEN &&
1726                             cipso_v4_map_cat_rng_valid(doi_def,
1727                                                        &tag[4],
1728                                                        tag_len - 4) < 0) {
1729                                 err_offset = opt_iter + 4;
1730                                 goto validate_return_locked;
1731                         }
1732                         break;
1733                 case CIPSO_V4_TAG_LOCAL:
1734                         /* This is a non-standard tag that we only allow for
1735                          * local connections, so if the incoming interface is
1736                          * not the loopback device drop the packet. Further,
1737                          * there is no legitimate reason for setting this from
1738                          * userspace so reject it if skb is NULL. */
1739                         if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) {
1740                                 err_offset = opt_iter;
1741                                 goto validate_return_locked;
1742                         }
1743                         if (tag_len != CIPSO_V4_TAG_LOC_BLEN) {
1744                                 err_offset = opt_iter + 1;
1745                                 goto validate_return_locked;
1746                         }
1747                         break;
1748                 default:
1749                         err_offset = opt_iter;
1750                         goto validate_return_locked;
1751                 }
1752 
1753                 tag += tag_len;
1754                 opt_iter += tag_len;
1755         }
1756 
1757 validate_return_locked:
1758         rcu_read_unlock();
1759 validate_return:
1760         *option = opt + err_offset;
1761         return err_offset;
1762 }
1763 
1764 /**
1765  * cipso_v4_error - Send the correct response for a bad packet
1766  * @skb: the packet
1767  * @error: the error code
1768  * @gateway: CIPSO gateway flag
1769  *
1770  * Description:
1771  * Based on the error code given in @error, send an ICMP error message back to
1772  * the originating host.  From the IETF draft ...
1773  *
1774  *  "If the contents of the CIPSO [option] are valid but the security label is
1775  *   outside of the configured host or port label range, the datagram is
1776  *   discarded and an ICMP 'destination unreachable' (type 3) is generated and
1777  *   returned.  The code field of the ICMP is set to 'communication with
1778  *   destination network administratively prohibited' (code 9) or to
1779  *   'communication with destination host administratively prohibited'
1780  *   (code 10).  The value of the code is dependent on whether the originator
1781  *   of the ICMP message is acting as a CIPSO host or a CIPSO gateway.  The
1782  *   recipient of the ICMP message MUST be able to handle either value.  The
1783  *   same procedure is performed if a CIPSO [option] can not be added to an
1784  *   IP packet because it is too large to fit in the IP options area."
1785  *
1786  *  "If the error is triggered by receipt of an ICMP message, the message is
1787  *   discarded and no response is permitted (consistent with general ICMP
1788  *   processing rules)."
1789  *
1790  */
1791 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
1792 {
1793         if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
1794                 return;
1795 
1796         if (gateway)
1797                 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
1798         else
1799                 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
1800 }
1801 
1802 /**
1803  * cipso_v4_genopt - Generate a CIPSO option
1804  * @buf: the option buffer
1805  * @buf_len: the size of opt_buf
1806  * @doi_def: the CIPSO DOI to use
1807  * @secattr: the security attributes
1808  *
1809  * Description:
1810  * Generate a CIPSO option using the DOI definition and security attributes
1811  * passed to the function.  Returns the length of the option on success and
1812  * negative values on failure.
1813  *
1814  */
1815 static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
1816                            const struct cipso_v4_doi *doi_def,
1817                            const struct netlbl_lsm_secattr *secattr)
1818 {
1819         int ret_val;
1820         u32 iter;
1821 
1822         if (buf_len <= CIPSO_V4_HDR_LEN)
1823                 return -ENOSPC;
1824 
1825         /* XXX - This code assumes only one tag per CIPSO option which isn't
1826          * really a good assumption to make but since we only support the MAC
1827          * tags right now it is a safe assumption. */
1828         iter = 0;
1829         do {
1830                 memset(buf, 0, buf_len);
1831                 switch (doi_def->tags[iter]) {
1832                 case CIPSO_V4_TAG_RBITMAP:
1833                         ret_val = cipso_v4_gentag_rbm(doi_def,
1834                                                    secattr,
1835                                                    &buf[CIPSO_V4_HDR_LEN],
1836                                                    buf_len - CIPSO_V4_HDR_LEN);
1837                         break;
1838                 case CIPSO_V4_TAG_ENUM:
1839                         ret_val = cipso_v4_gentag_enum(doi_def,
1840                                                    secattr,
1841                                                    &buf[CIPSO_V4_HDR_LEN],
1842                                                    buf_len - CIPSO_V4_HDR_LEN);
1843                         break;
1844                 case CIPSO_V4_TAG_RANGE:
1845                         ret_val = cipso_v4_gentag_rng(doi_def,
1846                                                    secattr,
1847                                                    &buf[CIPSO_V4_HDR_LEN],
1848                                                    buf_len - CIPSO_V4_HDR_LEN);
1849                         break;
1850                 case CIPSO_V4_TAG_LOCAL:
1851                         ret_val = cipso_v4_gentag_loc(doi_def,
1852                                                    secattr,
1853                                                    &buf[CIPSO_V4_HDR_LEN],
1854                                                    buf_len - CIPSO_V4_HDR_LEN);
1855                         break;
1856                 default:
1857                         return -EPERM;
1858                 }
1859 
1860                 iter++;
1861         } while (ret_val < 0 &&
1862                  iter < CIPSO_V4_TAG_MAXCNT &&
1863                  doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
1864         if (ret_val < 0)
1865                 return ret_val;
1866         cipso_v4_gentag_hdr(doi_def, buf, ret_val);
1867         return CIPSO_V4_HDR_LEN + ret_val;
1868 }
1869 
1870 /**
1871  * cipso_v4_sock_setattr - Add a CIPSO option to a socket
1872  * @sk: the socket
1873  * @doi_def: the CIPSO DOI to use
1874  * @secattr: the specific security attributes of the socket
1875  *
1876  * Description:
1877  * Set the CIPSO option on the given socket using the DOI definition and
1878  * security attributes passed to the function.  This function requires
1879  * exclusive access to @sk, which means it either needs to be in the
1880  * process of being created or locked.  Returns zero on success and negative
1881  * values on failure.
1882  *
1883  */
1884 int cipso_v4_sock_setattr(struct sock *sk,
1885                           const struct cipso_v4_doi *doi_def,
1886                           const struct netlbl_lsm_secattr *secattr)
1887 {
1888         int ret_val = -EPERM;
1889         unsigned char *buf = NULL;
1890         u32 buf_len;
1891         u32 opt_len;
1892         struct ip_options_rcu *old, *opt = NULL;
1893         struct inet_sock *sk_inet;
1894         struct inet_connection_sock *sk_conn;
1895 
1896         /* In the case of sock_create_lite(), the sock->sk field is not
1897          * defined yet but it is not a problem as the only users of these
1898          * "lite" PF_INET sockets are functions which do an accept() call
1899          * afterwards so we will label the socket as part of the accept(). */
1900         if (!sk)
1901                 return 0;
1902 
1903         /* We allocate the maximum CIPSO option size here so we are probably
1904          * being a little wasteful, but it makes our life _much_ easier later
1905          * on and after all we are only talking about 40 bytes. */
1906         buf_len = CIPSO_V4_OPT_LEN_MAX;
1907         buf = kmalloc(buf_len, GFP_ATOMIC);
1908         if (!buf) {
1909                 ret_val = -ENOMEM;
1910                 goto socket_setattr_failure;
1911         }
1912 
1913         ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1914         if (ret_val < 0)
1915                 goto socket_setattr_failure;
1916         buf_len = ret_val;
1917 
1918         /* We can't use ip_options_get() directly because it makes a call to
1919          * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1920          * we won't always have CAP_NET_RAW even though we _always_ want to
1921          * set the IPOPT_CIPSO option. */
1922         opt_len = (buf_len + 3) & ~3;
1923         opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
1924         if (!opt) {
1925                 ret_val = -ENOMEM;
1926                 goto socket_setattr_failure;
1927         }
1928         memcpy(opt->opt.__data, buf, buf_len);
1929         opt->opt.optlen = opt_len;
1930         opt->opt.cipso = sizeof(struct iphdr);
1931         kfree(buf);
1932         buf = NULL;
1933 
1934         sk_inet = inet_sk(sk);
1935 
1936         old = rcu_dereference_protected(sk_inet->inet_opt, sock_owned_by_user(sk));
1937         if (sk_inet->is_icsk) {
1938                 sk_conn = inet_csk(sk);
1939                 if (old)
1940                         sk_conn->icsk_ext_hdr_len -= old->opt.optlen;
1941                 sk_conn->icsk_ext_hdr_len += opt->opt.optlen;
1942                 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
1943         }
1944         rcu_assign_pointer(sk_inet->inet_opt, opt);
1945         if (old)
1946                 kfree_rcu(old, rcu);
1947 
1948         return 0;
1949 
1950 socket_setattr_failure:
1951         kfree(buf);
1952         kfree(opt);
1953         return ret_val;
1954 }
1955 
1956 /**
1957  * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket
1958  * @req: the connection request socket
1959  * @doi_def: the CIPSO DOI to use
1960  * @secattr: the specific security attributes of the socket
1961  *
1962  * Description:
1963  * Set the CIPSO option on the given socket using the DOI definition and
1964  * security attributes passed to the function.  Returns zero on success and
1965  * negative values on failure.
1966  *
1967  */
1968 int cipso_v4_req_setattr(struct request_sock *req,
1969                          const struct cipso_v4_doi *doi_def,
1970                          const struct netlbl_lsm_secattr *secattr)
1971 {
1972         int ret_val = -EPERM;
1973         unsigned char *buf = NULL;
1974         u32 buf_len;
1975         u32 opt_len;
1976         struct ip_options_rcu *opt = NULL;
1977         struct inet_request_sock *req_inet;
1978 
1979         /* We allocate the maximum CIPSO option size here so we are probably
1980          * being a little wasteful, but it makes our life _much_ easier later
1981          * on and after all we are only talking about 40 bytes. */
1982         buf_len = CIPSO_V4_OPT_LEN_MAX;
1983         buf = kmalloc(buf_len, GFP_ATOMIC);
1984         if (!buf) {
1985                 ret_val = -ENOMEM;
1986                 goto req_setattr_failure;
1987         }
1988 
1989         ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
1990         if (ret_val < 0)
1991                 goto req_setattr_failure;
1992         buf_len = ret_val;
1993 
1994         /* We can't use ip_options_get() directly because it makes a call to
1995          * ip_options_get_alloc() which allocates memory with GFP_KERNEL and
1996          * we won't always have CAP_NET_RAW even though we _always_ want to
1997          * set the IPOPT_CIPSO option. */
1998         opt_len = (buf_len + 3) & ~3;
1999         opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC);
2000         if (!opt) {
2001                 ret_val = -ENOMEM;
2002                 goto req_setattr_failure;
2003         }
2004         memcpy(opt->opt.__data, buf, buf_len);
2005         opt->opt.optlen = opt_len;
2006         opt->opt.cipso = sizeof(struct iphdr);
2007         kfree(buf);
2008         buf = NULL;
2009 
2010         req_inet = inet_rsk(req);
2011         opt = xchg(&req_inet->opt, opt);
2012         if (opt)
2013                 kfree_rcu(opt, rcu);
2014 
2015         return 0;
2016 
2017 req_setattr_failure:
2018         kfree(buf);
2019         kfree(opt);
2020         return ret_val;
2021 }
2022 
2023 /**
2024  * cipso_v4_delopt - Delete the CIPSO option from a set of IP options
2025  * @opt_ptr: IP option pointer
2026  *
2027  * Description:
2028  * Deletes the CIPSO IP option from a set of IP options and makes the necessary
2029  * adjustments to the IP option structure.  Returns zero on success, negative
2030  * values on failure.
2031  *
2032  */
2033 static int cipso_v4_delopt(struct ip_options_rcu **opt_ptr)
2034 {
2035         int hdr_delta = 0;
2036         struct ip_options_rcu *opt = *opt_ptr;
2037 
2038         if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) {
2039                 u8 cipso_len;
2040                 u8 cipso_off;
2041                 unsigned char *cipso_ptr;
2042                 int iter;
2043                 int optlen_new;
2044 
2045                 cipso_off = opt->opt.cipso - sizeof(struct iphdr);
2046                 cipso_ptr = &opt->opt.__data[cipso_off];
2047                 cipso_len = cipso_ptr[1];
2048 
2049                 if (opt->opt.srr > opt->opt.cipso)
2050                         opt->opt.srr -= cipso_len;
2051                 if (opt->opt.rr > opt->opt.cipso)
2052                         opt->opt.rr -= cipso_len;
2053                 if (opt->opt.ts > opt->opt.cipso)
2054                         opt->opt.ts -= cipso_len;
2055                 if (opt->opt.router_alert > opt->opt.cipso)
2056                         opt->opt.router_alert -= cipso_len;
2057                 opt->opt.cipso = 0;
2058 
2059                 memmove(cipso_ptr, cipso_ptr + cipso_len,
2060                         opt->opt.optlen - cipso_off - cipso_len);
2061 
2062                 /* determining the new total option length is tricky because of
2063                  * the padding necessary, the only thing i can think to do at
2064                  * this point is walk the options one-by-one, skipping the
2065                  * padding at the end to determine the actual option size and
2066                  * from there we can determine the new total option length */
2067                 iter = 0;
2068                 optlen_new = 0;
2069                 while (iter < opt->opt.optlen)
2070                         if (opt->opt.__data[iter] != IPOPT_NOP) {
2071                                 iter += opt->opt.__data[iter + 1];
2072                                 optlen_new = iter;
2073                         } else
2074                                 iter++;
2075                 hdr_delta = opt->opt.optlen;
2076                 opt->opt.optlen = (optlen_new + 3) & ~3;
2077                 hdr_delta -= opt->opt.optlen;
2078         } else {
2079                 /* only the cipso option was present on the socket so we can
2080                  * remove the entire option struct */
2081                 *opt_ptr = NULL;
2082                 hdr_delta = opt->opt.optlen;
2083                 kfree_rcu(opt, rcu);
2084         }
2085 
2086         return hdr_delta;
2087 }
2088 
2089 /**
2090  * cipso_v4_sock_delattr - Delete the CIPSO option from a socket
2091  * @sk: the socket
2092  *
2093  * Description:
2094  * Removes the CIPSO option from a socket, if present.
2095  *
2096  */
2097 void cipso_v4_sock_delattr(struct sock *sk)
2098 {
2099         int hdr_delta;
2100         struct ip_options_rcu *opt;
2101         struct inet_sock *sk_inet;
2102 
2103         sk_inet = inet_sk(sk);
2104         opt = rcu_dereference_protected(sk_inet->inet_opt, 1);
2105         if (!opt || opt->opt.cipso == 0)
2106                 return;
2107 
2108         hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt);
2109         if (sk_inet->is_icsk && hdr_delta > 0) {
2110                 struct inet_connection_sock *sk_conn = inet_csk(sk);
2111                 sk_conn->icsk_ext_hdr_len -= hdr_delta;
2112                 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
2113         }
2114 }
2115 
2116 /**
2117  * cipso_v4_req_delattr - Delete the CIPSO option from a request socket
2118  * @reg: the request socket
2119  *
2120  * Description:
2121  * Removes the CIPSO option from a request socket, if present.
2122  *
2123  */
2124 void cipso_v4_req_delattr(struct request_sock *req)
2125 {
2126         struct ip_options_rcu *opt;
2127         struct inet_request_sock *req_inet;
2128 
2129         req_inet = inet_rsk(req);
2130         opt = req_inet->opt;
2131         if (!opt || opt->opt.cipso == 0)
2132                 return;
2133 
2134         cipso_v4_delopt(&req_inet->opt);
2135 }
2136 
2137 /**
2138  * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
2139  * @cipso: the CIPSO v4 option
2140  * @secattr: the security attributes
2141  *
2142  * Description:
2143  * Inspect @cipso and return the security attributes in @secattr.  Returns zero
2144  * on success and negative values on failure.
2145  *
2146  */
2147 int cipso_v4_getattr(const unsigned char *cipso,
2148                      struct netlbl_lsm_secattr *secattr)
2149 {
2150         int ret_val = -ENOMSG;
2151         u32 doi;
2152         struct cipso_v4_doi *doi_def;
2153 
2154         if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0)
2155                 return 0;
2156 
2157         doi = get_unaligned_be32(&cipso[2]);
2158         rcu_read_lock();
2159         doi_def = cipso_v4_doi_search(doi);
2160         if (!doi_def)
2161                 goto getattr_return;
2162         /* XXX - This code assumes only one tag per CIPSO option which isn't
2163          * really a good assumption to make but since we only support the MAC
2164          * tags right now it is a safe assumption. */
2165         switch (cipso[6]) {
2166         case CIPSO_V4_TAG_RBITMAP:
2167                 ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr);
2168                 break;
2169         case CIPSO_V4_TAG_ENUM:
2170                 ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr);
2171                 break;
2172         case CIPSO_V4_TAG_RANGE:
2173                 ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr);
2174                 break;
2175         case CIPSO_V4_TAG_LOCAL:
2176                 ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr);
2177                 break;
2178         }
2179         if (ret_val == 0)
2180                 secattr->type = NETLBL_NLTYPE_CIPSOV4;
2181 
2182 getattr_return:
2183         rcu_read_unlock();
2184         return ret_val;
2185 }
2186 
2187 /**
2188  * cipso_v4_sock_getattr - Get the security attributes from a sock
2189  * @sk: the sock
2190  * @secattr: the security attributes
2191  *
2192  * Description:
2193  * Query @sk to see if there is a CIPSO option attached to the sock and if
2194  * there is return the CIPSO security attributes in @secattr.  This function
2195  * requires that @sk be locked, or privately held, but it does not do any
2196  * locking itself.  Returns zero on success and negative values on failure.
2197  *
2198  */
2199 int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
2200 {
2201         struct ip_options_rcu *opt;
2202         int res = -ENOMSG;
2203 
2204         rcu_read_lock();
2205         opt = rcu_dereference(inet_sk(sk)->inet_opt);
2206         if (opt && opt->opt.cipso)
2207                 res = cipso_v4_getattr(opt->opt.__data +
2208                                                 opt->opt.cipso -
2209                                                 sizeof(struct iphdr),
2210                                        secattr);
2211         rcu_read_unlock();
2212         return res;
2213 }
2214 
2215 /**
2216  * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
2217  * @skb: the packet
2218  * @secattr: the security attributes
2219  *
2220  * Description:
2221  * Set the CIPSO option on the given packet based on the security attributes.
2222  * Returns a pointer to the IP header on success and NULL on failure.
2223  *
2224  */
2225 int cipso_v4_skbuff_setattr(struct sk_buff *skb,
2226                             const struct cipso_v4_doi *doi_def,
2227                             const struct netlbl_lsm_secattr *secattr)
2228 {
2229         int ret_val;
2230         struct iphdr *iph;
2231         struct ip_options *opt = &IPCB(skb)->opt;
2232         unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
2233         u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
2234         u32 opt_len;
2235         int len_delta;
2236 
2237         ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
2238         if (ret_val < 0)
2239                 return ret_val;
2240         buf_len = ret_val;
2241         opt_len = (buf_len + 3) & ~3;
2242 
2243         /* we overwrite any existing options to ensure that we have enough
2244          * room for the CIPSO option, the reason is that we _need_ to guarantee
2245          * that the security label is applied to the packet - we do the same
2246          * thing when using the socket options and it hasn't caused a problem,
2247          * if we need to we can always revisit this choice later */
2248 
2249         len_delta = opt_len - opt->optlen;
2250         /* if we don't ensure enough headroom we could panic on the skb_push()
2251          * call below so make sure we have enough, we are also "mangling" the
2252          * packet so we should probably do a copy-on-write call anyway */
2253         ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
2254         if (ret_val < 0)
2255                 return ret_val;
2256 
2257         if (len_delta > 0) {
2258                 /* we assume that the header + opt->optlen have already been
2259                  * "pushed" in ip_options_build() or similar */
2260                 iph = ip_hdr(skb);
2261                 skb_push(skb, len_delta);
2262                 memmove((char *)iph - len_delta, iph, iph->ihl << 2);
2263                 skb_reset_network_header(skb);
2264                 iph = ip_hdr(skb);
2265         } else if (len_delta < 0) {
2266                 iph = ip_hdr(skb);
2267                 memset(iph + 1, IPOPT_NOP, opt->optlen);
2268         } else
2269                 iph = ip_hdr(skb);
2270 
2271         if (opt->optlen > 0)
2272                 memset(opt, 0, sizeof(*opt));
2273         opt->optlen = opt_len;
2274         opt->cipso = sizeof(struct iphdr);
2275         opt->is_changed = 1;
2276 
2277         /* we have to do the following because we are being called from a
2278          * netfilter hook which means the packet already has had the header
2279          * fields populated and the checksum calculated - yes this means we
2280          * are doing more work than needed but we do it to keep the core
2281          * stack clean and tidy */
2282         memcpy(iph + 1, buf, buf_len);
2283         if (opt_len > buf_len)
2284                 memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
2285         if (len_delta != 0) {
2286                 iph->ihl = 5 + (opt_len >> 2);
2287                 iph->tot_len = htons(skb->len);
2288         }
2289         ip_send_check(iph);
2290 
2291         return 0;
2292 }
2293 
2294 /**
2295  * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
2296  * @skb: the packet
2297  *
2298  * Description:
2299  * Removes any and all CIPSO options from the given packet.  Returns zero on
2300  * success, negative values on failure.
2301  *
2302  */
2303 int cipso_v4_skbuff_delattr(struct sk_buff *skb)
2304 {
2305         int ret_val;
2306         struct iphdr *iph;
2307         struct ip_options *opt = &IPCB(skb)->opt;
2308         unsigned char *cipso_ptr;
2309 
2310         if (opt->cipso == 0)
2311                 return 0;
2312 
2313         /* since we are changing the packet we should make a copy */
2314         ret_val = skb_cow(skb, skb_headroom(skb));
2315         if (ret_val < 0)
2316                 return ret_val;
2317 
2318         /* the easiest thing to do is just replace the cipso option with noop
2319          * options since we don't change the size of the packet, although we
2320          * still need to recalculate the checksum */
2321 
2322         iph = ip_hdr(skb);
2323         cipso_ptr = (unsigned char *)iph + opt->cipso;
2324         memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]);
2325         opt->cipso = 0;
2326         opt->is_changed = 1;
2327 
2328         ip_send_check(iph);
2329 
2330         return 0;
2331 }
2332 
2333 /*
2334  * Setup Functions
2335  */
2336 
2337 /**
2338  * cipso_v4_init - Initialize the CIPSO module
2339  *
2340  * Description:
2341  * Initialize the CIPSO module and prepare it for use.  Returns zero on success
2342  * and negative values on failure.
2343  *
2344  */
2345 static int __init cipso_v4_init(void)
2346 {
2347         int ret_val;
2348 
2349         ret_val = cipso_v4_cache_init();
2350         if (ret_val != 0)
2351                 panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
2352                       ret_val);
2353 
2354         return 0;
2355 }
2356 
2357 subsys_initcall(cipso_v4_init);
2358 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp