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