Linux Audio

Check our new training course

Linux debugging, profiling, tracing and performance analysis training

Apr 14-17, 2025
Register
Loading...
Note: File does not exist in v3.15.
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * CALIPSO - Common Architecture Label IPv6 Security Option
   4 *
   5 * This is an implementation of the CALIPSO protocol as specified in
   6 * RFC 5570.
   7 *
   8 * Authors: Paul Moore <paul.moore@hp.com>
   9 *          Huw Davies <huw@codeweavers.com>
  10 */
  11
  12/* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
  13 * (c) Copyright Huw Davies <huw@codeweavers.com>, 2015
  14 */
  15
  16#include <linux/init.h>
  17#include <linux/types.h>
  18#include <linux/rcupdate.h>
  19#include <linux/list.h>
  20#include <linux/spinlock.h>
  21#include <linux/string.h>
  22#include <linux/jhash.h>
  23#include <linux/audit.h>
  24#include <linux/slab.h>
  25#include <net/ip.h>
  26#include <net/icmp.h>
  27#include <net/tcp.h>
  28#include <net/netlabel.h>
  29#include <net/calipso.h>
  30#include <linux/atomic.h>
  31#include <linux/bug.h>
  32#include <asm/unaligned.h>
  33#include <linux/crc-ccitt.h>
  34
  35/* Maximium size of the calipso option including
  36 * the two-byte TLV header.
  37 */
  38#define CALIPSO_OPT_LEN_MAX (2 + 252)
  39
  40/* Size of the minimum calipso option including
  41 * the two-byte TLV header.
  42 */
  43#define CALIPSO_HDR_LEN (2 + 8)
  44
  45/* Maximium size of the calipso option including
  46 * the two-byte TLV header and upto 3 bytes of
  47 * leading pad and 7 bytes of trailing pad.
  48 */
  49#define CALIPSO_OPT_LEN_MAX_WITH_PAD (3 + CALIPSO_OPT_LEN_MAX + 7)
  50
  51 /* Maximium size of u32 aligned buffer required to hold calipso
  52  * option.  Max of 3 initial pad bytes starting from buffer + 3.
  53  * i.e. the worst case is when the previous tlv finishes on 4n + 3.
  54  */
  55#define CALIPSO_MAX_BUFFER (6 + CALIPSO_OPT_LEN_MAX)
  56
  57/* List of available DOI definitions */
  58static DEFINE_SPINLOCK(calipso_doi_list_lock);
  59static LIST_HEAD(calipso_doi_list);
  60
  61/* Label mapping cache */
  62int calipso_cache_enabled = 1;
  63int calipso_cache_bucketsize = 10;
  64#define CALIPSO_CACHE_BUCKETBITS     7
  65#define CALIPSO_CACHE_BUCKETS        BIT(CALIPSO_CACHE_BUCKETBITS)
  66#define CALIPSO_CACHE_REORDERLIMIT   10
  67struct calipso_map_cache_bkt {
  68	spinlock_t lock;
  69	u32 size;
  70	struct list_head list;
  71};
  72
  73struct calipso_map_cache_entry {
  74	u32 hash;
  75	unsigned char *key;
  76	size_t key_len;
  77
  78	struct netlbl_lsm_cache *lsm_data;
  79
  80	u32 activity;
  81	struct list_head list;
  82};
  83
  84static struct calipso_map_cache_bkt *calipso_cache;
  85
  86/* Label Mapping Cache Functions
  87 */
  88
  89/**
  90 * calipso_cache_entry_free - Frees a cache entry
  91 * @entry: the entry to free
  92 *
  93 * Description:
  94 * This function frees the memory associated with a cache entry including the
  95 * LSM cache data if there are no longer any users, i.e. reference count == 0.
  96 *
  97 */
  98static void calipso_cache_entry_free(struct calipso_map_cache_entry *entry)
  99{
 100	if (entry->lsm_data)
 101		netlbl_secattr_cache_free(entry->lsm_data);
 102	kfree(entry->key);
 103	kfree(entry);
 104}
 105
 106/**
 107 * calipso_map_cache_hash - Hashing function for the CALIPSO cache
 108 * @key: the hash key
 109 * @key_len: the length of the key in bytes
 110 *
 111 * Description:
 112 * The CALIPSO tag hashing function.  Returns a 32-bit hash value.
 113 *
 114 */
 115static u32 calipso_map_cache_hash(const unsigned char *key, u32 key_len)
 116{
 117	return jhash(key, key_len, 0);
 118}
 119
 120/**
 121 * calipso_cache_init - Initialize the CALIPSO cache
 122 *
 123 * Description:
 124 * Initializes the CALIPSO label mapping cache, this function should be called
 125 * before any of the other functions defined in this file.  Returns zero on
 126 * success, negative values on error.
 127 *
 128 */
 129static int __init calipso_cache_init(void)
 130{
 131	u32 iter;
 132
 133	calipso_cache = kcalloc(CALIPSO_CACHE_BUCKETS,
 134				sizeof(struct calipso_map_cache_bkt),
 135				GFP_KERNEL);
 136	if (!calipso_cache)
 137		return -ENOMEM;
 138
 139	for (iter = 0; iter < CALIPSO_CACHE_BUCKETS; iter++) {
 140		spin_lock_init(&calipso_cache[iter].lock);
 141		calipso_cache[iter].size = 0;
 142		INIT_LIST_HEAD(&calipso_cache[iter].list);
 143	}
 144
 145	return 0;
 146}
 147
 148/**
 149 * calipso_cache_invalidate - Invalidates the current CALIPSO cache
 150 *
 151 * Description:
 152 * Invalidates and frees any entries in the CALIPSO cache.  Returns zero on
 153 * success and negative values on failure.
 154 *
 155 */
 156static void calipso_cache_invalidate(void)
 157{
 158	struct calipso_map_cache_entry *entry, *tmp_entry;
 159	u32 iter;
 160
 161	for (iter = 0; iter < CALIPSO_CACHE_BUCKETS; iter++) {
 162		spin_lock_bh(&calipso_cache[iter].lock);
 163		list_for_each_entry_safe(entry,
 164					 tmp_entry,
 165					 &calipso_cache[iter].list, list) {
 166			list_del(&entry->list);
 167			calipso_cache_entry_free(entry);
 168		}
 169		calipso_cache[iter].size = 0;
 170		spin_unlock_bh(&calipso_cache[iter].lock);
 171	}
 172}
 173
 174/**
 175 * calipso_cache_check - Check the CALIPSO cache for a label mapping
 176 * @key: the buffer to check
 177 * @key_len: buffer length in bytes
 178 * @secattr: the security attribute struct to use
 179 *
 180 * Description:
 181 * This function checks the cache to see if a label mapping already exists for
 182 * the given key.  If there is a match then the cache is adjusted and the
 183 * @secattr struct is populated with the correct LSM security attributes.  The
 184 * cache is adjusted in the following manner if the entry is not already the
 185 * first in the cache bucket:
 186 *
 187 *  1. The cache entry's activity counter is incremented
 188 *  2. The previous (higher ranking) entry's activity counter is decremented
 189 *  3. If the difference between the two activity counters is geater than
 190 *     CALIPSO_CACHE_REORDERLIMIT the two entries are swapped
 191 *
 192 * Returns zero on success, -ENOENT for a cache miss, and other negative values
 193 * on error.
 194 *
 195 */
 196static int calipso_cache_check(const unsigned char *key,
 197			       u32 key_len,
 198			       struct netlbl_lsm_secattr *secattr)
 199{
 200	u32 bkt;
 201	struct calipso_map_cache_entry *entry;
 202	struct calipso_map_cache_entry *prev_entry = NULL;
 203	u32 hash;
 204
 205	if (!calipso_cache_enabled)
 206		return -ENOENT;
 207
 208	hash = calipso_map_cache_hash(key, key_len);
 209	bkt = hash & (CALIPSO_CACHE_BUCKETS - 1);
 210	spin_lock_bh(&calipso_cache[bkt].lock);
 211	list_for_each_entry(entry, &calipso_cache[bkt].list, list) {
 212		if (entry->hash == hash &&
 213		    entry->key_len == key_len &&
 214		    memcmp(entry->key, key, key_len) == 0) {
 215			entry->activity += 1;
 216			refcount_inc(&entry->lsm_data->refcount);
 217			secattr->cache = entry->lsm_data;
 218			secattr->flags |= NETLBL_SECATTR_CACHE;
 219			secattr->type = NETLBL_NLTYPE_CALIPSO;
 220			if (!prev_entry) {
 221				spin_unlock_bh(&calipso_cache[bkt].lock);
 222				return 0;
 223			}
 224
 225			if (prev_entry->activity > 0)
 226				prev_entry->activity -= 1;
 227			if (entry->activity > prev_entry->activity &&
 228			    entry->activity - prev_entry->activity >
 229			    CALIPSO_CACHE_REORDERLIMIT) {
 230				__list_del(entry->list.prev, entry->list.next);
 231				__list_add(&entry->list,
 232					   prev_entry->list.prev,
 233					   &prev_entry->list);
 234			}
 235
 236			spin_unlock_bh(&calipso_cache[bkt].lock);
 237			return 0;
 238		}
 239		prev_entry = entry;
 240	}
 241	spin_unlock_bh(&calipso_cache[bkt].lock);
 242
 243	return -ENOENT;
 244}
 245
 246/**
 247 * calipso_cache_add - Add an entry to the CALIPSO cache
 248 * @calipso_ptr: the CALIPSO option
 249 * @secattr: the packet's security attributes
 250 *
 251 * Description:
 252 * Add a new entry into the CALIPSO label mapping cache.  Add the new entry to
 253 * head of the cache bucket's list, if the cache bucket is out of room remove
 254 * the last entry in the list first.  It is important to note that there is
 255 * currently no checking for duplicate keys.  Returns zero on success,
 256 * negative values on failure.  The key stored starts at calipso_ptr + 2,
 257 * i.e. the type and length bytes are not stored, this corresponds to
 258 * calipso_ptr[1] bytes of data.
 259 *
 260 */
 261static int calipso_cache_add(const unsigned char *calipso_ptr,
 262			     const struct netlbl_lsm_secattr *secattr)
 263{
 264	int ret_val = -EPERM;
 265	u32 bkt;
 266	struct calipso_map_cache_entry *entry = NULL;
 267	struct calipso_map_cache_entry *old_entry = NULL;
 268	u32 calipso_ptr_len;
 269
 270	if (!calipso_cache_enabled || calipso_cache_bucketsize <= 0)
 271		return 0;
 272
 273	calipso_ptr_len = calipso_ptr[1];
 274
 275	entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
 276	if (!entry)
 277		return -ENOMEM;
 278	entry->key = kmemdup(calipso_ptr + 2, calipso_ptr_len, GFP_ATOMIC);
 279	if (!entry->key) {
 280		ret_val = -ENOMEM;
 281		goto cache_add_failure;
 282	}
 283	entry->key_len = calipso_ptr_len;
 284	entry->hash = calipso_map_cache_hash(calipso_ptr, calipso_ptr_len);
 285	refcount_inc(&secattr->cache->refcount);
 286	entry->lsm_data = secattr->cache;
 287
 288	bkt = entry->hash & (CALIPSO_CACHE_BUCKETS - 1);
 289	spin_lock_bh(&calipso_cache[bkt].lock);
 290	if (calipso_cache[bkt].size < calipso_cache_bucketsize) {
 291		list_add(&entry->list, &calipso_cache[bkt].list);
 292		calipso_cache[bkt].size += 1;
 293	} else {
 294		old_entry = list_entry(calipso_cache[bkt].list.prev,
 295				       struct calipso_map_cache_entry, list);
 296		list_del(&old_entry->list);
 297		list_add(&entry->list, &calipso_cache[bkt].list);
 298		calipso_cache_entry_free(old_entry);
 299	}
 300	spin_unlock_bh(&calipso_cache[bkt].lock);
 301
 302	return 0;
 303
 304cache_add_failure:
 305	if (entry)
 306		calipso_cache_entry_free(entry);
 307	return ret_val;
 308}
 309
 310/* DOI List Functions
 311 */
 312
 313/**
 314 * calipso_doi_search - Searches for a DOI definition
 315 * @doi: the DOI to search for
 316 *
 317 * Description:
 318 * Search the DOI definition list for a DOI definition with a DOI value that
 319 * matches @doi.  The caller is responsible for calling rcu_read_[un]lock().
 320 * Returns a pointer to the DOI definition on success and NULL on failure.
 321 */
 322static struct calipso_doi *calipso_doi_search(u32 doi)
 323{
 324	struct calipso_doi *iter;
 325
 326	list_for_each_entry_rcu(iter, &calipso_doi_list, list)
 327		if (iter->doi == doi && refcount_read(&iter->refcount))
 328			return iter;
 329	return NULL;
 330}
 331
 332/**
 333 * calipso_doi_add - Add a new DOI to the CALIPSO protocol engine
 334 * @doi_def: the DOI structure
 335 * @audit_info: NetLabel audit information
 336 *
 337 * Description:
 338 * The caller defines a new DOI for use by the CALIPSO engine and calls this
 339 * function to add it to the list of acceptable domains.  The caller must
 340 * ensure that the mapping table specified in @doi_def->map meets all of the
 341 * requirements of the mapping type (see calipso.h for details).  Returns
 342 * zero on success and non-zero on failure.
 343 *
 344 */
 345static int calipso_doi_add(struct calipso_doi *doi_def,
 346			   struct netlbl_audit *audit_info)
 347{
 348	int ret_val = -EINVAL;
 349	u32 doi;
 350	u32 doi_type;
 351	struct audit_buffer *audit_buf;
 352
 353	doi = doi_def->doi;
 354	doi_type = doi_def->type;
 355
 356	if (doi_def->doi == CALIPSO_DOI_UNKNOWN)
 357		goto doi_add_return;
 358
 359	refcount_set(&doi_def->refcount, 1);
 360
 361	spin_lock(&calipso_doi_list_lock);
 362	if (calipso_doi_search(doi_def->doi)) {
 363		spin_unlock(&calipso_doi_list_lock);
 364		ret_val = -EEXIST;
 365		goto doi_add_return;
 366	}
 367	list_add_tail_rcu(&doi_def->list, &calipso_doi_list);
 368	spin_unlock(&calipso_doi_list_lock);
 369	ret_val = 0;
 370
 371doi_add_return:
 372	audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_ADD, audit_info);
 373	if (audit_buf) {
 374		const char *type_str;
 375
 376		switch (doi_type) {
 377		case CALIPSO_MAP_PASS:
 378			type_str = "pass";
 379			break;
 380		default:
 381			type_str = "(unknown)";
 382		}
 383		audit_log_format(audit_buf,
 384				 " calipso_doi=%u calipso_type=%s res=%u",
 385				 doi, type_str, ret_val == 0 ? 1 : 0);
 386		audit_log_end(audit_buf);
 387	}
 388
 389	return ret_val;
 390}
 391
 392/**
 393 * calipso_doi_free - Frees a DOI definition
 394 * @doi_def: the DOI definition
 395 *
 396 * Description:
 397 * This function frees all of the memory associated with a DOI definition.
 398 *
 399 */
 400static void calipso_doi_free(struct calipso_doi *doi_def)
 401{
 402	kfree(doi_def);
 403}
 404
 405/**
 406 * calipso_doi_free_rcu - Frees a DOI definition via the RCU pointer
 407 * @entry: the entry's RCU field
 408 *
 409 * Description:
 410 * This function is designed to be used as a callback to the call_rcu()
 411 * function so that the memory allocated to the DOI definition can be released
 412 * safely.
 413 *
 414 */
 415static void calipso_doi_free_rcu(struct rcu_head *entry)
 416{
 417	struct calipso_doi *doi_def;
 418
 419	doi_def = container_of(entry, struct calipso_doi, rcu);
 420	calipso_doi_free(doi_def);
 421}
 422
 423/**
 424 * calipso_doi_remove - Remove an existing DOI from the CALIPSO protocol engine
 425 * @doi: the DOI value
 426 * @audit_secid: the LSM secid to use in the audit message
 427 *
 428 * Description:
 429 * Removes a DOI definition from the CALIPSO engine.  The NetLabel routines will
 430 * be called to release their own LSM domain mappings as well as our own
 431 * domain list.  Returns zero on success and negative values on failure.
 432 *
 433 */
 434static int calipso_doi_remove(u32 doi, struct netlbl_audit *audit_info)
 435{
 436	int ret_val;
 437	struct calipso_doi *doi_def;
 438	struct audit_buffer *audit_buf;
 439
 440	spin_lock(&calipso_doi_list_lock);
 441	doi_def = calipso_doi_search(doi);
 442	if (!doi_def) {
 443		spin_unlock(&calipso_doi_list_lock);
 444		ret_val = -ENOENT;
 445		goto doi_remove_return;
 446	}
 447	if (!refcount_dec_and_test(&doi_def->refcount)) {
 448		spin_unlock(&calipso_doi_list_lock);
 449		ret_val = -EBUSY;
 450		goto doi_remove_return;
 451	}
 452	list_del_rcu(&doi_def->list);
 453	spin_unlock(&calipso_doi_list_lock);
 454
 455	call_rcu(&doi_def->rcu, calipso_doi_free_rcu);
 456	ret_val = 0;
 457
 458doi_remove_return:
 459	audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_DEL, audit_info);
 460	if (audit_buf) {
 461		audit_log_format(audit_buf,
 462				 " calipso_doi=%u res=%u",
 463				 doi, ret_val == 0 ? 1 : 0);
 464		audit_log_end(audit_buf);
 465	}
 466
 467	return ret_val;
 468}
 469
 470/**
 471 * calipso_doi_getdef - Returns a reference to a valid DOI definition
 472 * @doi: the DOI value
 473 *
 474 * Description:
 475 * Searches for a valid DOI definition and if one is found it is returned to
 476 * the caller.  Otherwise NULL is returned.  The caller must ensure that
 477 * calipso_doi_putdef() is called when the caller is done.
 478 *
 479 */
 480static struct calipso_doi *calipso_doi_getdef(u32 doi)
 481{
 482	struct calipso_doi *doi_def;
 483
 484	rcu_read_lock();
 485	doi_def = calipso_doi_search(doi);
 486	if (!doi_def)
 487		goto doi_getdef_return;
 488	if (!refcount_inc_not_zero(&doi_def->refcount))
 489		doi_def = NULL;
 490
 491doi_getdef_return:
 492	rcu_read_unlock();
 493	return doi_def;
 494}
 495
 496/**
 497 * calipso_doi_putdef - Releases a reference for the given DOI definition
 498 * @doi_def: the DOI definition
 499 *
 500 * Description:
 501 * Releases a DOI definition reference obtained from calipso_doi_getdef().
 502 *
 503 */
 504static void calipso_doi_putdef(struct calipso_doi *doi_def)
 505{
 506	if (!doi_def)
 507		return;
 508
 509	if (!refcount_dec_and_test(&doi_def->refcount))
 510		return;
 511	spin_lock(&calipso_doi_list_lock);
 512	list_del_rcu(&doi_def->list);
 513	spin_unlock(&calipso_doi_list_lock);
 514
 515	call_rcu(&doi_def->rcu, calipso_doi_free_rcu);
 516}
 517
 518/**
 519 * calipso_doi_walk - Iterate through the DOI definitions
 520 * @skip_cnt: skip past this number of DOI definitions, updated
 521 * @callback: callback for each DOI definition
 522 * @cb_arg: argument for the callback function
 523 *
 524 * Description:
 525 * Iterate over the DOI definition list, skipping the first @skip_cnt entries.
 526 * For each entry call @callback, if @callback returns a negative value stop
 527 * 'walking' through the list and return.  Updates the value in @skip_cnt upon
 528 * return.  Returns zero on success, negative values on failure.
 529 *
 530 */
 531static int calipso_doi_walk(u32 *skip_cnt,
 532			    int (*callback)(struct calipso_doi *doi_def,
 533					    void *arg),
 534			    void *cb_arg)
 535{
 536	int ret_val = -ENOENT;
 537	u32 doi_cnt = 0;
 538	struct calipso_doi *iter_doi;
 539
 540	rcu_read_lock();
 541	list_for_each_entry_rcu(iter_doi, &calipso_doi_list, list)
 542		if (refcount_read(&iter_doi->refcount) > 0) {
 543			if (doi_cnt++ < *skip_cnt)
 544				continue;
 545			ret_val = callback(iter_doi, cb_arg);
 546			if (ret_val < 0) {
 547				doi_cnt--;
 548				goto doi_walk_return;
 549			}
 550		}
 551
 552doi_walk_return:
 553	rcu_read_unlock();
 554	*skip_cnt = doi_cnt;
 555	return ret_val;
 556}
 557
 558/**
 559 * calipso_validate - Validate a CALIPSO option
 560 * @skb: the packet
 561 * @option: the start of the option
 562 *
 563 * Description:
 564 * This routine is called to validate a CALIPSO option.
 565 * If the option is valid then %true is returned, otherwise
 566 * %false is returned.
 567 *
 568 * The caller should have already checked that the length of the
 569 * option (including the TLV header) is >= 10 and that the catmap
 570 * length is consistent with the option length.
 571 *
 572 * We leave checks on the level and categories to the socket layer.
 573 */
 574bool calipso_validate(const struct sk_buff *skb, const unsigned char *option)
 575{
 576	struct calipso_doi *doi_def;
 577	bool ret_val;
 578	u16 crc, len = option[1] + 2;
 579	static const u8 zero[2];
 580
 581	/* The original CRC runs over the option including the TLV header
 582	 * with the CRC-16 field (at offset 8) zeroed out. */
 583	crc = crc_ccitt(0xffff, option, 8);
 584	crc = crc_ccitt(crc, zero, sizeof(zero));
 585	if (len > 10)
 586		crc = crc_ccitt(crc, option + 10, len - 10);
 587	crc = ~crc;
 588	if (option[8] != (crc & 0xff) || option[9] != ((crc >> 8) & 0xff))
 589		return false;
 590
 591	rcu_read_lock();
 592	doi_def = calipso_doi_search(get_unaligned_be32(option + 2));
 593	ret_val = !!doi_def;
 594	rcu_read_unlock();
 595
 596	return ret_val;
 597}
 598
 599/**
 600 * calipso_map_cat_hton - Perform a category mapping from host to network
 601 * @doi_def: the DOI definition
 602 * @secattr: the security attributes
 603 * @net_cat: the zero'd out category bitmap in network/CALIPSO format
 604 * @net_cat_len: the length of the CALIPSO bitmap in bytes
 605 *
 606 * Description:
 607 * Perform a label mapping to translate a local MLS category bitmap to the
 608 * correct CALIPSO bitmap using the given DOI definition.  Returns the minimum
 609 * size in bytes of the network bitmap on success, negative values otherwise.
 610 *
 611 */
 612static int calipso_map_cat_hton(const struct calipso_doi *doi_def,
 613				const struct netlbl_lsm_secattr *secattr,
 614				unsigned char *net_cat,
 615				u32 net_cat_len)
 616{
 617	int spot = -1;
 618	u32 net_spot_max = 0;
 619	u32 net_clen_bits = net_cat_len * 8;
 620
 621	for (;;) {
 622		spot = netlbl_catmap_walk(secattr->attr.mls.cat,
 623					  spot + 1);
 624		if (spot < 0)
 625			break;
 626		if (spot >= net_clen_bits)
 627			return -ENOSPC;
 628		netlbl_bitmap_setbit(net_cat, spot, 1);
 629
 630		if (spot > net_spot_max)
 631			net_spot_max = spot;
 632	}
 633
 634	return (net_spot_max / 32 + 1) * 4;
 635}
 636
 637/**
 638 * calipso_map_cat_ntoh - Perform a category mapping from network to host
 639 * @doi_def: the DOI definition
 640 * @net_cat: the category bitmap in network/CALIPSO format
 641 * @net_cat_len: the length of the CALIPSO bitmap in bytes
 642 * @secattr: the security attributes
 643 *
 644 * Description:
 645 * Perform a label mapping to translate a CALIPSO bitmap to the correct local
 646 * MLS category bitmap using the given DOI definition.  Returns zero on
 647 * success, negative values on failure.
 648 *
 649 */
 650static int calipso_map_cat_ntoh(const struct calipso_doi *doi_def,
 651				const unsigned char *net_cat,
 652				u32 net_cat_len,
 653				struct netlbl_lsm_secattr *secattr)
 654{
 655	int ret_val;
 656	int spot = -1;
 657	u32 net_clen_bits = net_cat_len * 8;
 658
 659	for (;;) {
 660		spot = netlbl_bitmap_walk(net_cat,
 661					  net_clen_bits,
 662					  spot + 1,
 663					  1);
 664		if (spot < 0) {
 665			if (spot == -2)
 666				return -EFAULT;
 667			return 0;
 668		}
 669
 670		ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
 671					       spot,
 672					       GFP_ATOMIC);
 673		if (ret_val != 0)
 674			return ret_val;
 675	}
 676
 677	return -EINVAL;
 678}
 679
 680/**
 681 * calipso_pad_write - Writes pad bytes in TLV format
 682 * @buf: the buffer
 683 * @offset: offset from start of buffer to write padding
 684 * @count: number of pad bytes to write
 685 *
 686 * Description:
 687 * Write @count bytes of TLV padding into @buffer starting at offset @offset.
 688 * @count should be less than 8 - see RFC 4942.
 689 *
 690 */
 691static int calipso_pad_write(unsigned char *buf, unsigned int offset,
 692			     unsigned int count)
 693{
 694	if (WARN_ON_ONCE(count >= 8))
 695		return -EINVAL;
 696
 697	switch (count) {
 698	case 0:
 699		break;
 700	case 1:
 701		buf[offset] = IPV6_TLV_PAD1;
 702		break;
 703	default:
 704		buf[offset] = IPV6_TLV_PADN;
 705		buf[offset + 1] = count - 2;
 706		if (count > 2)
 707			memset(buf + offset + 2, 0, count - 2);
 708		break;
 709	}
 710	return 0;
 711}
 712
 713/**
 714 * calipso_genopt - Generate a CALIPSO option
 715 * @buf: the option buffer
 716 * @start: offset from which to write
 717 * @buf_len: the size of opt_buf
 718 * @doi_def: the CALIPSO DOI to use
 719 * @secattr: the security attributes
 720 *
 721 * Description:
 722 * Generate a CALIPSO option using the DOI definition and security attributes
 723 * passed to the function. This also generates upto three bytes of leading
 724 * padding that ensures that the option is 4n + 2 aligned.  It returns the
 725 * number of bytes written (including any initial padding).
 726 */
 727static int calipso_genopt(unsigned char *buf, u32 start, u32 buf_len,
 728			  const struct calipso_doi *doi_def,
 729			  const struct netlbl_lsm_secattr *secattr)
 730{
 731	int ret_val;
 732	u32 len, pad;
 733	u16 crc;
 734	static const unsigned char padding[4] = {2, 1, 0, 3};
 735	unsigned char *calipso;
 736
 737	/* CALIPSO has 4n + 2 alignment */
 738	pad = padding[start & 3];
 739	if (buf_len <= start + pad + CALIPSO_HDR_LEN)
 740		return -ENOSPC;
 741
 742	if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
 743		return -EPERM;
 744
 745	len = CALIPSO_HDR_LEN;
 746
 747	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
 748		ret_val = calipso_map_cat_hton(doi_def,
 749					       secattr,
 750					       buf + start + pad + len,
 751					       buf_len - start - pad - len);
 752		if (ret_val < 0)
 753			return ret_val;
 754		len += ret_val;
 755	}
 756
 757	calipso_pad_write(buf, start, pad);
 758	calipso = buf + start + pad;
 759
 760	calipso[0] = IPV6_TLV_CALIPSO;
 761	calipso[1] = len - 2;
 762	*(__be32 *)(calipso + 2) = htonl(doi_def->doi);
 763	calipso[6] = (len - CALIPSO_HDR_LEN) / 4;
 764	calipso[7] = secattr->attr.mls.lvl,
 765	crc = ~crc_ccitt(0xffff, calipso, len);
 766	calipso[8] = crc & 0xff;
 767	calipso[9] = (crc >> 8) & 0xff;
 768	return pad + len;
 769}
 770
 771/* Hop-by-hop hdr helper functions
 772 */
 773
 774/**
 775 * calipso_opt_update - Replaces socket's hop options with a new set
 776 * @sk: the socket
 777 * @hop: new hop options
 778 *
 779 * Description:
 780 * Replaces @sk's hop options with @hop.  @hop may be NULL to leave
 781 * the socket with no hop options.
 782 *
 783 */
 784static int calipso_opt_update(struct sock *sk, struct ipv6_opt_hdr *hop)
 785{
 786	struct ipv6_txoptions *old = txopt_get(inet6_sk(sk)), *txopts;
 787
 788	txopts = ipv6_renew_options(sk, old, IPV6_HOPOPTS, hop);
 789	txopt_put(old);
 790	if (IS_ERR(txopts))
 791		return PTR_ERR(txopts);
 792
 793	txopts = ipv6_update_options(sk, txopts);
 794	if (txopts) {
 795		atomic_sub(txopts->tot_len, &sk->sk_omem_alloc);
 796		txopt_put(txopts);
 797	}
 798
 799	return 0;
 800}
 801
 802/**
 803 * calipso_tlv_len - Returns the length of the TLV
 804 * @opt: the option header
 805 * @offset: offset of the TLV within the header
 806 *
 807 * Description:
 808 * Returns the length of the TLV option at offset @offset within
 809 * the option header @opt.  Checks that the entire TLV fits inside
 810 * the option header, returns a negative value if this is not the case.
 811 */
 812static int calipso_tlv_len(struct ipv6_opt_hdr *opt, unsigned int offset)
 813{
 814	unsigned char *tlv = (unsigned char *)opt;
 815	unsigned int opt_len = ipv6_optlen(opt), tlv_len;
 816
 817	if (offset < sizeof(*opt) || offset >= opt_len)
 818		return -EINVAL;
 819	if (tlv[offset] == IPV6_TLV_PAD1)
 820		return 1;
 821	if (offset + 1 >= opt_len)
 822		return -EINVAL;
 823	tlv_len = tlv[offset + 1] + 2;
 824	if (offset + tlv_len > opt_len)
 825		return -EINVAL;
 826	return tlv_len;
 827}
 828
 829/**
 830 * calipso_opt_find - Finds the CALIPSO option in an IPv6 hop options header
 831 * @hop: the hop options header
 832 * @start: on return holds the offset of any leading padding
 833 * @end: on return holds the offset of the first non-pad TLV after CALIPSO
 834 *
 835 * Description:
 836 * Finds the space occupied by a CALIPSO option (including any leading and
 837 * trailing padding).
 838 *
 839 * If a CALIPSO option exists set @start and @end to the
 840 * offsets within @hop of the start of padding before the first
 841 * CALIPSO option and the end of padding after the first CALIPSO
 842 * option.  In this case the function returns 0.
 843 *
 844 * In the absence of a CALIPSO option, @start and @end will be
 845 * set to the start and end of any trailing padding in the header.
 846 * This is useful when appending a new option, as the caller may want
 847 * to overwrite some of this padding.  In this case the function will
 848 * return -ENOENT.
 849 */
 850static int calipso_opt_find(struct ipv6_opt_hdr *hop, unsigned int *start,
 851			    unsigned int *end)
 852{
 853	int ret_val = -ENOENT, tlv_len;
 854	unsigned int opt_len, offset, offset_s = 0, offset_e = 0;
 855	unsigned char *opt = (unsigned char *)hop;
 856
 857	opt_len = ipv6_optlen(hop);
 858	offset = sizeof(*hop);
 859
 860	while (offset < opt_len) {
 861		tlv_len = calipso_tlv_len(hop, offset);
 862		if (tlv_len < 0)
 863			return tlv_len;
 864
 865		switch (opt[offset]) {
 866		case IPV6_TLV_PAD1:
 867		case IPV6_TLV_PADN:
 868			if (offset_e)
 869				offset_e = offset;
 870			break;
 871		case IPV6_TLV_CALIPSO:
 872			ret_val = 0;
 873			offset_e = offset;
 874			break;
 875		default:
 876			if (offset_e == 0)
 877				offset_s = offset;
 878			else
 879				goto out;
 880		}
 881		offset += tlv_len;
 882	}
 883
 884out:
 885	if (offset_s)
 886		*start = offset_s + calipso_tlv_len(hop, offset_s);
 887	else
 888		*start = sizeof(*hop);
 889	if (offset_e)
 890		*end = offset_e + calipso_tlv_len(hop, offset_e);
 891	else
 892		*end = opt_len;
 893
 894	return ret_val;
 895}
 896
 897/**
 898 * calipso_opt_insert - Inserts a CALIPSO option into an IPv6 hop opt hdr
 899 * @hop: the original hop options header
 900 * @doi_def: the CALIPSO DOI to use
 901 * @secattr: the specific security attributes of the socket
 902 *
 903 * Description:
 904 * Creates a new hop options header based on @hop with a
 905 * CALIPSO option added to it.  If @hop already contains a CALIPSO
 906 * option this is overwritten, otherwise the new option is appended
 907 * after any existing options.  If @hop is NULL then the new header
 908 * will contain just the CALIPSO option and any needed padding.
 909 *
 910 */
 911static struct ipv6_opt_hdr *
 912calipso_opt_insert(struct ipv6_opt_hdr *hop,
 913		   const struct calipso_doi *doi_def,
 914		   const struct netlbl_lsm_secattr *secattr)
 915{
 916	unsigned int start, end, buf_len, pad, hop_len;
 917	struct ipv6_opt_hdr *new;
 918	int ret_val;
 919
 920	if (hop) {
 921		hop_len = ipv6_optlen(hop);
 922		ret_val = calipso_opt_find(hop, &start, &end);
 923		if (ret_val && ret_val != -ENOENT)
 924			return ERR_PTR(ret_val);
 925	} else {
 926		hop_len = 0;
 927		start = sizeof(*hop);
 928		end = 0;
 929	}
 930
 931	buf_len = hop_len + start - end + CALIPSO_OPT_LEN_MAX_WITH_PAD;
 932	new = kzalloc(buf_len, GFP_ATOMIC);
 933	if (!new)
 934		return ERR_PTR(-ENOMEM);
 935
 936	if (start > sizeof(*hop))
 937		memcpy(new, hop, start);
 938	ret_val = calipso_genopt((unsigned char *)new, start, buf_len, doi_def,
 939				 secattr);
 940	if (ret_val < 0) {
 941		kfree(new);
 942		return ERR_PTR(ret_val);
 943	}
 944
 945	buf_len = start + ret_val;
 946	/* At this point buf_len aligns to 4n, so (buf_len & 4) pads to 8n */
 947	pad = ((buf_len & 4) + (end & 7)) & 7;
 948	calipso_pad_write((unsigned char *)new, buf_len, pad);
 949	buf_len += pad;
 950
 951	if (end != hop_len) {
 952		memcpy((char *)new + buf_len, (char *)hop + end, hop_len - end);
 953		buf_len += hop_len - end;
 954	}
 955	new->nexthdr = 0;
 956	new->hdrlen = buf_len / 8 - 1;
 957
 958	return new;
 959}
 960
 961/**
 962 * calipso_opt_del - Removes the CALIPSO option from an option header
 963 * @hop: the original header
 964 * @new: the new header
 965 *
 966 * Description:
 967 * Creates a new header based on @hop without any CALIPSO option.  If @hop
 968 * doesn't contain a CALIPSO option it returns -ENOENT.  If @hop contains
 969 * no other non-padding options, it returns zero with @new set to NULL.
 970 * Otherwise it returns zero, creates a new header without the CALIPSO
 971 * option (and removing as much padding as possible) and returns with
 972 * @new set to that header.
 973 *
 974 */
 975static int calipso_opt_del(struct ipv6_opt_hdr *hop,
 976			   struct ipv6_opt_hdr **new)
 977{
 978	int ret_val;
 979	unsigned int start, end, delta, pad, hop_len;
 980
 981	ret_val = calipso_opt_find(hop, &start, &end);
 982	if (ret_val)
 983		return ret_val;
 984
 985	hop_len = ipv6_optlen(hop);
 986	if (start == sizeof(*hop) && end == hop_len) {
 987		/* There's no other option in the header so return NULL */
 988		*new = NULL;
 989		return 0;
 990	}
 991
 992	delta = (end - start) & ~7;
 993	*new = kzalloc(hop_len - delta, GFP_ATOMIC);
 994	if (!*new)
 995		return -ENOMEM;
 996
 997	memcpy(*new, hop, start);
 998	(*new)->hdrlen -= delta / 8;
 999	pad = (end - start) & 7;
1000	calipso_pad_write((unsigned char *)*new, start, pad);
1001	if (end != hop_len)
1002		memcpy((char *)*new + start + pad, (char *)hop + end,
1003		       hop_len - end);
1004
1005	return 0;
1006}
1007
1008/**
1009 * calipso_opt_getattr - Get the security attributes from a memory block
1010 * @calipso: the CALIPSO option
1011 * @secattr: the security attributes
1012 *
1013 * Description:
1014 * Inspect @calipso and return the security attributes in @secattr.
1015 * Returns zero on success and negative values on failure.
1016 *
1017 */
1018static int calipso_opt_getattr(const unsigned char *calipso,
1019			       struct netlbl_lsm_secattr *secattr)
1020{
1021	int ret_val = -ENOMSG;
1022	u32 doi, len = calipso[1], cat_len = calipso[6] * 4;
1023	struct calipso_doi *doi_def;
1024
1025	if (cat_len + 8 > len)
1026		return -EINVAL;
1027
1028	if (calipso_cache_check(calipso + 2, calipso[1], secattr) == 0)
1029		return 0;
1030
1031	doi = get_unaligned_be32(calipso + 2);
1032	rcu_read_lock();
1033	doi_def = calipso_doi_search(doi);
1034	if (!doi_def)
1035		goto getattr_return;
1036
1037	secattr->attr.mls.lvl = calipso[7];
1038	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
1039
1040	if (cat_len) {
1041		ret_val = calipso_map_cat_ntoh(doi_def,
1042					       calipso + 10,
1043					       cat_len,
1044					       secattr);
1045		if (ret_val != 0) {
1046			netlbl_catmap_free(secattr->attr.mls.cat);
1047			goto getattr_return;
1048		}
1049
1050		if (secattr->attr.mls.cat)
1051			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
1052	}
1053
1054	secattr->type = NETLBL_NLTYPE_CALIPSO;
1055
1056getattr_return:
1057	rcu_read_unlock();
1058	return ret_val;
1059}
1060
1061/* sock functions.
1062 */
1063
1064/**
1065 * calipso_sock_getattr - Get the security attributes from a sock
1066 * @sk: the sock
1067 * @secattr: the security attributes
1068 *
1069 * Description:
1070 * Query @sk to see if there is a CALIPSO option attached to the sock and if
1071 * there is return the CALIPSO security attributes in @secattr.  This function
1072 * requires that @sk be locked, or privately held, but it does not do any
1073 * locking itself.  Returns zero on success and negative values on failure.
1074 *
1075 */
1076static int calipso_sock_getattr(struct sock *sk,
1077				struct netlbl_lsm_secattr *secattr)
1078{
1079	struct ipv6_opt_hdr *hop;
1080	int opt_len, len, ret_val = -ENOMSG, offset;
1081	unsigned char *opt;
1082	struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
1083
1084	if (!txopts || !txopts->hopopt)
1085		goto done;
1086
1087	hop = txopts->hopopt;
1088	opt = (unsigned char *)hop;
1089	opt_len = ipv6_optlen(hop);
1090	offset = sizeof(*hop);
1091	while (offset < opt_len) {
1092		len = calipso_tlv_len(hop, offset);
1093		if (len < 0) {
1094			ret_val = len;
1095			goto done;
1096		}
1097		switch (opt[offset]) {
1098		case IPV6_TLV_CALIPSO:
1099			if (len < CALIPSO_HDR_LEN)
1100				ret_val = -EINVAL;
1101			else
1102				ret_val = calipso_opt_getattr(&opt[offset],
1103							      secattr);
1104			goto done;
1105		default:
1106			offset += len;
1107			break;
1108		}
1109	}
1110done:
1111	txopt_put(txopts);
1112	return ret_val;
1113}
1114
1115/**
1116 * calipso_sock_setattr - Add a CALIPSO option to a socket
1117 * @sk: the socket
1118 * @doi_def: the CALIPSO DOI to use
1119 * @secattr: the specific security attributes of the socket
1120 *
1121 * Description:
1122 * Set the CALIPSO option on the given socket using the DOI definition and
1123 * security attributes passed to the function.  This function requires
1124 * exclusive access to @sk, which means it either needs to be in the
1125 * process of being created or locked.  Returns zero on success and negative
1126 * values on failure.
1127 *
1128 */
1129static int calipso_sock_setattr(struct sock *sk,
1130				const struct calipso_doi *doi_def,
1131				const struct netlbl_lsm_secattr *secattr)
1132{
1133	int ret_val;
1134	struct ipv6_opt_hdr *old, *new;
1135	struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
1136
1137	old = NULL;
1138	if (txopts)
1139		old = txopts->hopopt;
1140
1141	new = calipso_opt_insert(old, doi_def, secattr);
1142	txopt_put(txopts);
1143	if (IS_ERR(new))
1144		return PTR_ERR(new);
1145
1146	ret_val = calipso_opt_update(sk, new);
1147
1148	kfree(new);
1149	return ret_val;
1150}
1151
1152/**
1153 * calipso_sock_delattr - Delete the CALIPSO option from a socket
1154 * @sk: the socket
1155 *
1156 * Description:
1157 * Removes the CALIPSO option from a socket, if present.
1158 *
1159 */
1160static void calipso_sock_delattr(struct sock *sk)
1161{
1162	struct ipv6_opt_hdr *new_hop;
1163	struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk));
1164
1165	if (!txopts || !txopts->hopopt)
1166		goto done;
1167
1168	if (calipso_opt_del(txopts->hopopt, &new_hop))
1169		goto done;
1170
1171	calipso_opt_update(sk, new_hop);
1172	kfree(new_hop);
1173
1174done:
1175	txopt_put(txopts);
1176}
1177
1178/* request sock functions.
1179 */
1180
1181/**
1182 * calipso_req_setattr - Add a CALIPSO option to a connection request socket
1183 * @req: the connection request socket
1184 * @doi_def: the CALIPSO DOI to use
1185 * @secattr: the specific security attributes of the socket
1186 *
1187 * Description:
1188 * Set the CALIPSO option on the given socket using the DOI definition and
1189 * security attributes passed to the function.  Returns zero on success and
1190 * negative values on failure.
1191 *
1192 */
1193static int calipso_req_setattr(struct request_sock *req,
1194			       const struct calipso_doi *doi_def,
1195			       const struct netlbl_lsm_secattr *secattr)
1196{
1197	struct ipv6_txoptions *txopts;
1198	struct inet_request_sock *req_inet = inet_rsk(req);
1199	struct ipv6_opt_hdr *old, *new;
1200	struct sock *sk = sk_to_full_sk(req_to_sk(req));
1201
1202	if (req_inet->ipv6_opt && req_inet->ipv6_opt->hopopt)
1203		old = req_inet->ipv6_opt->hopopt;
1204	else
1205		old = NULL;
1206
1207	new = calipso_opt_insert(old, doi_def, secattr);
1208	if (IS_ERR(new))
1209		return PTR_ERR(new);
1210
1211	txopts = ipv6_renew_options(sk, req_inet->ipv6_opt, IPV6_HOPOPTS, new);
1212
1213	kfree(new);
1214
1215	if (IS_ERR(txopts))
1216		return PTR_ERR(txopts);
1217
1218	txopts = xchg(&req_inet->ipv6_opt, txopts);
1219	if (txopts) {
1220		atomic_sub(txopts->tot_len, &sk->sk_omem_alloc);
1221		txopt_put(txopts);
1222	}
1223
1224	return 0;
1225}
1226
1227/**
1228 * calipso_req_delattr - Delete the CALIPSO option from a request socket
1229 * @reg: the request socket
1230 *
1231 * Description:
1232 * Removes the CALIPSO option from a request socket, if present.
1233 *
1234 */
1235static void calipso_req_delattr(struct request_sock *req)
1236{
1237	struct inet_request_sock *req_inet = inet_rsk(req);
1238	struct ipv6_opt_hdr *new;
1239	struct ipv6_txoptions *txopts;
1240	struct sock *sk = sk_to_full_sk(req_to_sk(req));
1241
1242	if (!req_inet->ipv6_opt || !req_inet->ipv6_opt->hopopt)
1243		return;
1244
1245	if (calipso_opt_del(req_inet->ipv6_opt->hopopt, &new))
1246		return; /* Nothing to do */
1247
1248	txopts = ipv6_renew_options(sk, req_inet->ipv6_opt, IPV6_HOPOPTS, new);
1249
1250	if (!IS_ERR(txopts)) {
1251		txopts = xchg(&req_inet->ipv6_opt, txopts);
1252		if (txopts) {
1253			atomic_sub(txopts->tot_len, &sk->sk_omem_alloc);
1254			txopt_put(txopts);
1255		}
1256	}
1257	kfree(new);
1258}
1259
1260/* skbuff functions.
1261 */
1262
1263/**
1264 * calipso_skbuff_optptr - Find the CALIPSO option in the packet
1265 * @skb: the packet
1266 *
1267 * Description:
1268 * Parse the packet's IP header looking for a CALIPSO option.  Returns a pointer
1269 * to the start of the CALIPSO option on success, NULL if one if not found.
1270 *
1271 */
1272static unsigned char *calipso_skbuff_optptr(const struct sk_buff *skb)
1273{
1274	const struct ipv6hdr *ip6_hdr = ipv6_hdr(skb);
1275	int offset;
1276
1277	if (ip6_hdr->nexthdr != NEXTHDR_HOP)
1278		return NULL;
1279
1280	offset = ipv6_find_tlv(skb, sizeof(*ip6_hdr), IPV6_TLV_CALIPSO);
1281	if (offset >= 0)
1282		return (unsigned char *)ip6_hdr + offset;
1283
1284	return NULL;
1285}
1286
1287/**
1288 * calipso_skbuff_setattr - Set the CALIPSO option on a packet
1289 * @skb: the packet
1290 * @doi_def: the CALIPSO DOI to use
1291 * @secattr: the security attributes
1292 *
1293 * Description:
1294 * Set the CALIPSO option on the given packet based on the security attributes.
1295 * Returns a pointer to the IP header on success and NULL on failure.
1296 *
1297 */
1298static int calipso_skbuff_setattr(struct sk_buff *skb,
1299				  const struct calipso_doi *doi_def,
1300				  const struct netlbl_lsm_secattr *secattr)
1301{
1302	int ret_val;
1303	struct ipv6hdr *ip6_hdr;
1304	struct ipv6_opt_hdr *hop;
1305	unsigned char buf[CALIPSO_MAX_BUFFER];
1306	int len_delta, new_end, pad, payload;
1307	unsigned int start, end;
1308
1309	ip6_hdr = ipv6_hdr(skb);
1310	if (ip6_hdr->nexthdr == NEXTHDR_HOP) {
1311		hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
1312		ret_val = calipso_opt_find(hop, &start, &end);
1313		if (ret_val && ret_val != -ENOENT)
1314			return ret_val;
1315	} else {
1316		start = 0;
1317		end = 0;
1318	}
1319
1320	memset(buf, 0, sizeof(buf));
1321	ret_val = calipso_genopt(buf, start & 3, sizeof(buf), doi_def, secattr);
1322	if (ret_val < 0)
1323		return ret_val;
1324
1325	new_end = start + ret_val;
1326	/* At this point new_end aligns to 4n, so (new_end & 4) pads to 8n */
1327	pad = ((new_end & 4) + (end & 7)) & 7;
1328	len_delta = new_end - (int)end + pad;
1329	ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
1330	if (ret_val < 0)
1331		return ret_val;
1332
1333	ip6_hdr = ipv6_hdr(skb); /* Reset as skb_cow() may have moved it */
1334
1335	if (len_delta) {
1336		if (len_delta > 0)
1337			skb_push(skb, len_delta);
1338		else
1339			skb_pull(skb, -len_delta);
1340		memmove((char *)ip6_hdr - len_delta, ip6_hdr,
1341			sizeof(*ip6_hdr) + start);
1342		skb_reset_network_header(skb);
1343		ip6_hdr = ipv6_hdr(skb);
1344		payload = ntohs(ip6_hdr->payload_len);
1345		ip6_hdr->payload_len = htons(payload + len_delta);
1346	}
1347
1348	hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
1349	if (start == 0) {
1350		struct ipv6_opt_hdr *new_hop = (struct ipv6_opt_hdr *)buf;
1351
1352		new_hop->nexthdr = ip6_hdr->nexthdr;
1353		new_hop->hdrlen = len_delta / 8 - 1;
1354		ip6_hdr->nexthdr = NEXTHDR_HOP;
1355	} else {
1356		hop->hdrlen += len_delta / 8;
1357	}
1358	memcpy((char *)hop + start, buf + (start & 3), new_end - start);
1359	calipso_pad_write((unsigned char *)hop, new_end, pad);
1360
1361	return 0;
1362}
1363
1364/**
1365 * calipso_skbuff_delattr - Delete any CALIPSO options from a packet
1366 * @skb: the packet
1367 *
1368 * Description:
1369 * Removes any and all CALIPSO options from the given packet.  Returns zero on
1370 * success, negative values on failure.
1371 *
1372 */
1373static int calipso_skbuff_delattr(struct sk_buff *skb)
1374{
1375	int ret_val;
1376	struct ipv6hdr *ip6_hdr;
1377	struct ipv6_opt_hdr *old_hop;
1378	u32 old_hop_len, start = 0, end = 0, delta, size, pad;
1379
1380	if (!calipso_skbuff_optptr(skb))
1381		return 0;
1382
1383	/* since we are changing the packet we should make a copy */
1384	ret_val = skb_cow(skb, skb_headroom(skb));
1385	if (ret_val < 0)
1386		return ret_val;
1387
1388	ip6_hdr = ipv6_hdr(skb);
1389	old_hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
1390	old_hop_len = ipv6_optlen(old_hop);
1391
1392	ret_val = calipso_opt_find(old_hop, &start, &end);
1393	if (ret_val)
1394		return ret_val;
1395
1396	if (start == sizeof(*old_hop) && end == old_hop_len) {
1397		/* There's no other option in the header so we delete
1398		 * the whole thing. */
1399		delta = old_hop_len;
1400		size = sizeof(*ip6_hdr);
1401		ip6_hdr->nexthdr = old_hop->nexthdr;
1402	} else {
1403		delta = (end - start) & ~7;
1404		if (delta)
1405			old_hop->hdrlen -= delta / 8;
1406		pad = (end - start) & 7;
1407		size = sizeof(*ip6_hdr) + start + pad;
1408		calipso_pad_write((unsigned char *)old_hop, start, pad);
1409	}
1410
1411	if (delta) {
1412		skb_pull(skb, delta);
1413		memmove((char *)ip6_hdr + delta, ip6_hdr, size);
1414		skb_reset_network_header(skb);
1415	}
1416
1417	return 0;
1418}
1419
1420static const struct netlbl_calipso_ops ops = {
1421	.doi_add          = calipso_doi_add,
1422	.doi_free         = calipso_doi_free,
1423	.doi_remove       = calipso_doi_remove,
1424	.doi_getdef       = calipso_doi_getdef,
1425	.doi_putdef       = calipso_doi_putdef,
1426	.doi_walk         = calipso_doi_walk,
1427	.sock_getattr     = calipso_sock_getattr,
1428	.sock_setattr     = calipso_sock_setattr,
1429	.sock_delattr     = calipso_sock_delattr,
1430	.req_setattr      = calipso_req_setattr,
1431	.req_delattr      = calipso_req_delattr,
1432	.opt_getattr      = calipso_opt_getattr,
1433	.skbuff_optptr    = calipso_skbuff_optptr,
1434	.skbuff_setattr   = calipso_skbuff_setattr,
1435	.skbuff_delattr   = calipso_skbuff_delattr,
1436	.cache_invalidate = calipso_cache_invalidate,
1437	.cache_add        = calipso_cache_add
1438};
1439
1440/**
1441 * calipso_init - Initialize the CALIPSO module
1442 *
1443 * Description:
1444 * Initialize the CALIPSO module and prepare it for use.  Returns zero on
1445 * success and negative values on failure.
1446 *
1447 */
1448int __init calipso_init(void)
1449{
1450	int ret_val;
1451
1452	ret_val = calipso_cache_init();
1453	if (!ret_val)
1454		netlbl_calipso_ops_register(&ops);
1455	return ret_val;
1456}
1457
1458void calipso_exit(void)
1459{
1460	netlbl_calipso_ops_register(NULL);
1461	calipso_cache_invalidate();
1462	kfree(calipso_cache);
1463}