/* * CIPSO - Commercial IP Security Option * * This is an implementation of the CIPSO 2.2 protocol as specified in * draft-ietf-cipso-ipsecurity-01.txt with additional tag types as found in * FIPS-188, copies of both documents can be found in the Documentation * directory. While CIPSO never became a full IETF RFC standard many vendors * have chosen to adopt the protocol and over the years it has become a * de-facto standard for labeled networking. * * Author: Paul Moore <paul.moore@hp.com> * */ /* * (c) Copyright Hewlett-Packard Development Company, L.P., 2006 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See * the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <linux/init.h> #include <linux/types.h> #include <linux/rcupdate.h> #include <linux/list.h> #include <linux/spinlock.h> #include <linux/string.h> #include <linux/jhash.h> #include <net/ip.h> #include <net/icmp.h> #include <net/tcp.h> #include <net/netlabel.h> #include <net/cipso_ipv4.h> #include <asm/atomic.h> #include <asm/bug.h> struct cipso_v4_domhsh_entry { char *domain; u32 valid; struct list_head list; struct rcu_head rcu; }; /* List of available DOI definitions */ /* XXX - Updates should be minimal so having a single lock for the * cipso_v4_doi_list and the cipso_v4_doi_list->dom_list should be * okay. */ /* XXX - This currently assumes a minimal number of different DOIs in use, * if in practice there are a lot of different DOIs this list should * probably be turned into a hash table or something similar so we * can do quick lookups. */ static DEFINE_SPINLOCK(cipso_v4_doi_list_lock); static struct list_head cipso_v4_doi_list = LIST_HEAD_INIT(cipso_v4_doi_list); /* Label mapping cache */ int cipso_v4_cache_enabled = 1; int cipso_v4_cache_bucketsize = 10; #define CIPSO_V4_CACHE_BUCKETBITS 7 #define CIPSO_V4_CACHE_BUCKETS (1 << CIPSO_V4_CACHE_BUCKETBITS) #define CIPSO_V4_CACHE_REORDERLIMIT 10 struct cipso_v4_map_cache_bkt { spinlock_t lock; u32 size; struct list_head list; }; struct cipso_v4_map_cache_entry { u32 hash; unsigned char *key; size_t key_len; struct netlbl_lsm_cache *lsm_data; u32 activity; struct list_head list; }; static struct cipso_v4_map_cache_bkt *cipso_v4_cache = NULL; /* Restricted bitmap (tag #1) flags */ int cipso_v4_rbm_optfmt = 0; int cipso_v4_rbm_strictvalid = 1; /* * Helper Functions */ /** * cipso_v4_bitmap_walk - Walk a bitmap looking for a bit * @bitmap: the bitmap * @bitmap_len: length in bits * @offset: starting offset * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit * * Description: * Starting at @offset, walk the bitmap from left to right until either the * desired bit is found or we reach the end. Return the bit offset, -1 if * not found, or -2 if error. */ static int cipso_v4_bitmap_walk(const unsigned char *bitmap, u32 bitmap_len, u32 offset, u8 state) { u32 bit_spot; u32 byte_offset; unsigned char bitmask; unsigned char byte; /* gcc always rounds to zero when doing integer division */ byte_offset = offset / 8; byte = bitmap[byte_offset]; bit_spot = offset; bitmask = 0x80 >> (offset % 8); while (bit_spot < bitmap_len) { if ((state && (byte & bitmask) == bitmask) || (state == 0 && (byte & bitmask) == 0)) return bit_spot; bit_spot++; bitmask >>= 1; if (bitmask == 0) { byte = bitmap[++byte_offset]; bitmask = 0x80; } } return -1; } /** * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap * @bitmap: the bitmap * @bit: the bit * @state: if non-zero, set the bit (1) else clear the bit (0) * * Description: * Set a single bit in the bitmask. Returns zero on success, negative values * on error. */ static void cipso_v4_bitmap_setbit(unsigned char *bitmap, u32 bit, u8 state) { u32 byte_spot; u8 bitmask; /* gcc always rounds to zero when doing integer division */ byte_spot = bit / 8; bitmask = 0x80 >> (bit % 8); if (state) bitmap[byte_spot] |= bitmask; else bitmap[byte_spot] &= ~bitmask; } /** * cipso_v4_doi_domhsh_free - Frees a domain list entry * @entry: the entry's RCU field * * Description: * This function is designed to be used as a callback to the call_rcu() * function so that the memory allocated to a domain list entry can be released * safely. * */ static void cipso_v4_doi_domhsh_free(struct rcu_head *entry) { struct cipso_v4_domhsh_entry *ptr; ptr = container_of(entry, struct cipso_v4_domhsh_entry, rcu); kfree(ptr->domain); kfree(ptr); } /** * cipso_v4_cache_entry_free - Frees a cache entry * @entry: the entry to free * * Description: * This function frees the memory associated with a cache entry including the * LSM cache data if there are no longer any users, i.e. reference count == 0. * */ static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry) { if (entry->lsm_data) netlbl_secattr_cache_free(entry->lsm_data); kfree(entry->key); kfree(entry); } /** * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache * @key: the hash key * @key_len: the length of the key in bytes * * Description: * The CIPSO tag hashing function. Returns a 32-bit hash value. * */ static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len) { return jhash(key, key_len, 0); } /* * Label Mapping Cache Functions */ /** * cipso_v4_cache_init - Initialize the CIPSO cache * * Description: * Initializes the CIPSO label mapping cache, this function should be called * before any of the other functions defined in this file. Returns zero on * success, negative values on error. * */ static int cipso_v4_cache_init(void) { u32 iter; cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS, sizeof(struct cipso_v4_map_cache_bkt), GFP_KERNEL); if (cipso_v4_cache == NULL) return -ENOMEM; for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { spin_lock_init(&cipso_v4_cache[iter].lock); cipso_v4_cache[iter].size = 0; INIT_LIST_HEAD(&cipso_v4_cache[iter].list); } return 0; } /** * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache * * Description: * Invalidates and frees any entries in the CIPSO cache. Returns zero on * success and negative values on failure. * */ void cipso_v4_cache_invalidate(void) { struct cipso_v4_map_cache_entry *entry, *tmp_entry; u32 iter; for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) { spin_lock_bh(&cipso_v4_cache[iter].lock); list_for_each_entry_safe(entry, tmp_entry, &cipso_v4_cache[iter].list, list) { list_del(&entry->list); cipso_v4_cache_entry_free(entry); } cipso_v4_cache[iter].size = 0; spin_unlock_bh(&cipso_v4_cache[iter].lock); } return; } /** * cipso_v4_cache_check - Check the CIPSO cache for a label mapping * @key: the buffer to check * @key_len: buffer length in bytes * @secattr: the security attribute struct to use * * Description: * This function checks the cache to see if a label mapping already exists for * the given key. If there is a match then the cache is adjusted and the * @secattr struct is populated with the correct LSM security attributes. The * cache is adjusted in the following manner if the entry is not already the * first in the cache bucket: * * 1. The cache entry's activity counter is incremented * 2. The previous (higher ranking) entry's activity counter is decremented * 3. If the difference between the two activity counters is geater than * CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped * * Returns zero on success, -ENOENT for a cache miss, and other negative values * on error. * */ static int cipso_v4_cache_check(const unsigned char *key, u32 key_len, struct netlbl_lsm_secattr *secattr) { u32 bkt; struct cipso_v4_map_cache_entry *entry; struct cipso_v4_map_cache_entry *prev_entry = NULL; u32 hash; if (!cipso_v4_cache_enabled) return -ENOENT; hash = cipso_v4_map_cache_hash(key, key_len); bkt = hash & (CIPSO_V4_CACHE_BUCKETBITS - 1); spin_lock_bh(&cipso_v4_cache[bkt].lock); list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) { if (entry->hash == hash && entry->key_len == key_len && memcmp(entry->key, key, key_len) == 0) { entry->activity += 1; atomic_inc(&entry->lsm_data->refcount); secattr->cache = entry->lsm_data; if (prev_entry == NULL) { spin_unlock_bh(&cipso_v4_cache[bkt].lock); return 0; } if (prev_entry->activity > 0) prev_entry->activity -= 1; if (entry->activity > prev_entry->activity && entry->activity - prev_entry->activity > CIPSO_V4_CACHE_REORDERLIMIT) { __list_del(entry->list.prev, entry->list.next); __list_add(&entry->list, prev_entry->list.prev, &prev_entry->list); } spin_unlock_bh(&cipso_v4_cache[bkt].lock); return 0; } prev_entry = entry; } spin_unlock_bh(&cipso_v4_cache[bkt].lock); return -ENOENT; } /** * cipso_v4_cache_add - Add an entry to the CIPSO cache * @skb: the packet * @secattr: the packet's security attributes * * Description: * Add a new entry into the CIPSO label mapping cache. Add the new entry to * head of the cache bucket's list, if the cache bucket is out of room remove * the last entry in the list first. It is important to note that there is * currently no checking for duplicate keys. Returns zero on success, * negative values on failure. * */ int cipso_v4_cache_add(const struct sk_buff *skb, const struct netlbl_lsm_secattr *secattr) { int ret_val = -EPERM; u32 bkt; struct cipso_v4_map_cache_entry *entry = NULL; struct cipso_v4_map_cache_entry *old_entry = NULL; unsigned char *cipso_ptr; u32 cipso_ptr_len; if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0) return 0; cipso_ptr = CIPSO_V4_OPTPTR(skb); cipso_ptr_len = cipso_ptr[1]; entry = kzalloc(sizeof(*entry), GFP_ATOMIC); if (entry == NULL) return -ENOMEM; entry->key = kmalloc(cipso_ptr_len, GFP_ATOMIC); if (entry->key == NULL) { ret_val = -ENOMEM; goto cache_add_failure; } memcpy(entry->key, cipso_ptr, cipso_ptr_len); entry->key_len = cipso_ptr_len; entry->hash = cipso_v4_map_cache_hash(cipso_ptr, cipso_ptr_len); atomic_inc(&secattr->cache->refcount); entry->lsm_data = secattr->cache; bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETBITS - 1); spin_lock_bh(&cipso_v4_cache[bkt].lock); if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) { list_add(&entry->list, &cipso_v4_cache[bkt].list); cipso_v4_cache[bkt].size += 1; } else { old_entry = list_entry(cipso_v4_cache[bkt].list.prev, struct cipso_v4_map_cache_entry, list); list_del(&old_entry->list); list_add(&entry->list, &cipso_v4_cache[bkt].list); cipso_v4_cache_entry_free(old_entry); } spin_unlock_bh(&cipso_v4_cache[bkt].lock); return 0; cache_add_failure: if (entry) cipso_v4_cache_entry_free(entry); return ret_val; } /* * DOI List Functions */ /** * cipso_v4_doi_search - Searches for a DOI definition * @doi: the DOI to search for * * Description: * Search the DOI definition list for a DOI definition with a DOI value that * matches @doi. The caller is responsibile for calling rcu_read_[un]lock(). * Returns a pointer to the DOI definition on success and NULL on failure. */ static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi) { struct cipso_v4_doi *iter; list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list) if (iter->doi == doi && iter->valid) return iter; return NULL; } /** * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine * @doi_def: the DOI structure * * Description: * The caller defines a new DOI for use by the CIPSO engine and calls this * function to add it to the list of acceptable domains. The caller must * ensure that the mapping table specified in @doi_def->map meets all of the * requirements of the mapping type (see cipso_ipv4.h for details). Returns * zero on success and non-zero on failure. * */ int cipso_v4_doi_add(struct cipso_v4_doi *doi_def) { if (doi_def == NULL || doi_def->doi == CIPSO_V4_DOI_UNKNOWN) return -EINVAL; doi_def->valid = 1; INIT_RCU_HEAD(&doi_def->rcu); INIT_LIST_HEAD(&doi_def->dom_list); rcu_read_lock(); if (cipso_v4_doi_search(doi_def->doi) != NULL) goto doi_add_failure_rlock; spin_lock(&cipso_v4_doi_list_lock); if (cipso_v4_doi_search(doi_def->doi) != NULL) goto doi_add_failure_slock; list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list); spin_unlock(&cipso_v4_doi_list_lock); rcu_read_unlock(); return 0; doi_add_failure_slock: spin_unlock(&cipso_v4_doi_list_lock); doi_add_failure_rlock: rcu_read_unlock(); return -EEXIST; } /** * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine * @doi: the DOI value * @audit_secid: the LSM secid to use in the audit message * @callback: the DOI cleanup/free callback * * Description: * Removes a DOI definition from the CIPSO engine, @callback is called to * free any memory. The NetLabel routines will be called to release their own * LSM domain mappings as well as our own domain list. Returns zero on * success and negative values on failure. * */ int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info, void (*callback) (struct rcu_head * head)) { struct cipso_v4_doi *doi_def; struct cipso_v4_domhsh_entry *dom_iter; rcu_read_lock(); if (cipso_v4_doi_search(doi) != NULL) { spin_lock(&cipso_v4_doi_list_lock); doi_def = cipso_v4_doi_search(doi); if (doi_def == NULL) { spin_unlock(&cipso_v4_doi_list_lock); rcu_read_unlock(); return -ENOENT; } doi_def->valid = 0; list_del_rcu(&doi_def->list); spin_unlock(&cipso_v4_doi_list_lock); list_for_each_entry_rcu(dom_iter, &doi_def->dom_list, list) if (dom_iter->valid) netlbl_domhsh_remove(dom_iter->domain, audit_info); cipso_v4_cache_invalidate(); rcu_read_unlock(); call_rcu(&doi_def->rcu, callback); return 0; } rcu_read_unlock(); return -ENOENT; } /** * cipso_v4_doi_getdef - Returns a pointer to a valid DOI definition * @doi: the DOI value * * Description: * Searches for a valid DOI definition and if one is found it is returned to * the caller. Otherwise NULL is returned. The caller must ensure that * rcu_read_lock() is held while accessing the returned definition. * */ struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi) { return cipso_v4_doi_search(doi); } /** * cipso_v4_doi_walk - Iterate through the DOI definitions * @skip_cnt: skip past this number of DOI definitions, updated * @callback: callback for each DOI definition * @cb_arg: argument for the callback function * * Description: * Iterate over the DOI definition list, skipping the first @skip_cnt entries. * For each entry call @callback, if @callback returns a negative value stop * 'walking' through the list and return. Updates the value in @skip_cnt upon * return. Returns zero on success, negative values on failure. * */ int cipso_v4_doi_walk(u32 *skip_cnt, int (*callback) (struct cipso_v4_doi *doi_def, void *arg), void *cb_arg) { int ret_val = -ENOENT; u32 doi_cnt = 0; struct cipso_v4_doi *iter_doi; rcu_read_lock(); list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list) if (iter_doi->valid) { if (doi_cnt++ < *skip_cnt) continue; ret_val = callback(iter_doi, cb_arg); if (ret_val < 0) { doi_cnt--; goto doi_walk_return; } } doi_walk_return: rcu_read_unlock(); *skip_cnt = doi_cnt; return ret_val; } /** * cipso_v4_doi_domhsh_add - Adds a domain entry to a DOI definition * @doi_def: the DOI definition * @domain: the domain to add * * Description: * Adds the @domain to the the DOI specified by @doi_def, this function * should only be called by external functions (i.e. NetLabel). This function * does allocate memory. Returns zero on success, negative values on failure. * */ int cipso_v4_doi_domhsh_add(struct cipso_v4_doi *doi_def, const char *domain) { struct cipso_v4_domhsh_entry *iter; struct cipso_v4_domhsh_entry *new_dom; new_dom = kzalloc(sizeof(*new_dom), GFP_KERNEL); if (new_dom == NULL) return -ENOMEM; if (domain) { new_dom->domain = kstrdup(domain, GFP_KERNEL); if (new_dom->domain == NULL) { kfree(new_dom); return -ENOMEM; } } new_dom->valid = 1; INIT_RCU_HEAD(&new_dom->rcu); rcu_read_lock(); spin_lock(&cipso_v4_doi_list_lock); list_for_each_entry_rcu(iter, &doi_def->dom_list, list) if (iter->valid && ((domain != NULL && iter->domain != NULL && strcmp(iter->domain, domain) == 0) || (domain == NULL && iter->domain == NULL))) { spin_unlock(&cipso_v4_doi_list_lock); rcu_read_unlock(); kfree(new_dom->domain); kfree(new_dom); return -EEXIST; } list_add_tail_rcu(&new_dom->list, &doi_def->dom_list); spin_unlock(&cipso_v4_doi_list_lock); rcu_read_unlock(); return 0; } /** * cipso_v4_doi_domhsh_remove - Removes a domain entry from a DOI definition * @doi_def: the DOI definition * @domain: the domain to remove * * Description: * Removes the @domain from the DOI specified by @doi_def, this function * should only be called by external functions (i.e. NetLabel). Returns zero * on success and negative values on error. * */ int cipso_v4_doi_domhsh_remove(struct cipso_v4_doi *doi_def, const char *domain) { struct cipso_v4_domhsh_entry *iter; rcu_read_lock(); spin_lock(&cipso_v4_doi_list_lock); list_for_each_entry_rcu(iter, &doi_def->dom_list, list) if (iter->valid && ((domain != NULL && iter->domain != NULL && strcmp(iter->domain, domain) == 0) || (domain == NULL && iter->domain == NULL))) { iter->valid = 0; list_del_rcu(&iter->list); spin_unlock(&cipso_v4_doi_list_lock); rcu_read_unlock(); call_rcu(&iter->rcu, cipso_v4_doi_domhsh_free); return 0; } spin_unlock(&cipso_v4_doi_list_lock); rcu_read_unlock(); return -ENOENT; } /* * Label Mapping Functions */ /** * cipso_v4_map_lvl_valid - Checks to see if the given level is understood * @doi_def: the DOI definition * @level: the level to check * * Description: * Checks the given level against the given DOI definition and returns a * negative value if the level does not have a valid mapping and a zero value * if the level is defined by the DOI. * */ static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level) { switch (doi_def->type) { case CIPSO_V4_MAP_PASS: return 0; case CIPSO_V4_MAP_STD: if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL) return 0; break; } return -EFAULT; } /** * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network * @doi_def: the DOI definition * @host_lvl: the host MLS level * @net_lvl: the network/CIPSO MLS level * * Description: * Perform a label mapping to translate a local MLS level to the correct * CIPSO level using the given DOI definition. Returns zero on success, * negative values otherwise. * */ static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def, u32 host_lvl, u32 *net_lvl) { switch (doi_def->type) { case CIPSO_V4_MAP_PASS: *net_lvl = host_lvl; return 0; case CIPSO_V4_MAP_STD: if (host_lvl < doi_def->map.std->lvl.local_size) { *net_lvl = doi_def->map.std->lvl.local[host_lvl]; return 0; } break; } return -EINVAL; } /** * cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host * @doi_def: the DOI definition * @net_lvl: the network/CIPSO MLS level * @host_lvl: the host MLS level * * Description: * Perform a label mapping to translate a CIPSO level to the correct local MLS * level using the given DOI definition. Returns zero on success, negative * values otherwise. * */ static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def, u32 net_lvl, u32 *host_lvl) { struct cipso_v4_std_map_tbl *map_tbl; switch (doi_def->type) { case CIPSO_V4_MAP_PASS: *host_lvl = net_lvl; return 0; case CIPSO_V4_MAP_STD: map_tbl = doi_def->map.std; if (net_lvl < map_tbl->lvl.cipso_size && map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) { *host_lvl = doi_def->map.std->lvl.cipso[net_lvl]; return 0; } break; } return -EINVAL; } /** * cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid * @doi_def: the DOI definition * @bitmap: category bitmap * @bitmap_len: bitmap length in bytes * * Description: * Checks the given category bitmap against the given DOI definition and * returns a negative value if any of the categories in the bitmap do not have * a valid mapping and a zero value if all of the categories are valid. * */ static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def, const unsigned char *bitmap, u32 bitmap_len) { int cat = -1; u32 bitmap_len_bits = bitmap_len * 8; u32 cipso_cat_size; u32 *cipso_array; switch (doi_def->type) { case CIPSO_V4_MAP_PASS: return 0; case CIPSO_V4_MAP_STD: cipso_cat_size = doi_def->map.std->cat.cipso_size; cipso_array = doi_def->map.std->cat.cipso; for (;;) { cat = cipso_v4_bitmap_walk(bitmap, bitmap_len_bits, cat + 1, 1); if (cat < 0) break; if (cat >= cipso_cat_size || cipso_array[cat] >= CIPSO_V4_INV_CAT) return -EFAULT; } if (cat == -1) return 0; break; } return -EFAULT; } /** * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network * @doi_def: the DOI definition * @host_cat: the category bitmap in host format * @host_cat_len: the length of the host's category bitmap in bytes * @net_cat: the zero'd out category bitmap in network/CIPSO format * @net_cat_len: the length of the CIPSO bitmap in bytes * * Description: * Perform a label mapping to translate a local MLS category bitmap to the * correct CIPSO bitmap using the given DOI definition. Returns the minimum * size in bytes of the network bitmap on success, negative values otherwise. * */ static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def, const unsigned char *host_cat, u32 host_cat_len, unsigned char *net_cat, u32 net_cat_len) { int host_spot = -1; u32 net_spot; u32 net_spot_max = 0; u32 host_clen_bits = host_cat_len * 8; u32 net_clen_bits = net_cat_len * 8; u32 host_cat_size; u32 *host_cat_array; switch (doi_def->type) { case CIPSO_V4_MAP_PASS: net_spot_max = host_cat_len; while (net_spot_max > 0 && host_cat[net_spot_max - 1] == 0) net_spot_max--; if (net_spot_max > net_cat_len) return -EINVAL; memcpy(net_cat, host_cat, net_spot_max); return net_spot_max; case CIPSO_V4_MAP_STD: host_cat_size = doi_def->map.std->cat.local_size; host_cat_array = doi_def->map.std->cat.local; for (;;) { host_spot = cipso_v4_bitmap_walk(host_cat, host_clen_bits, host_spot + 1, 1); if (host_spot < 0) break; if (host_spot >= host_cat_size) return -EPERM; net_spot = host_cat_array[host_spot]; if (net_spot >= net_clen_bits) return -ENOSPC; cipso_v4_bitmap_setbit(net_cat, net_spot, 1); if (net_spot > net_spot_max) net_spot_max = net_spot; } if (host_spot == -2) return -EFAULT; if (++net_spot_max % 8) return net_spot_max / 8 + 1; return net_spot_max / 8; } return -EINVAL; } /** * cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host * @doi_def: the DOI definition * @net_cat: the category bitmap in network/CIPSO format * @net_cat_len: the length of the CIPSO bitmap in bytes * @host_cat: the zero'd out category bitmap in host format * @host_cat_len: the length of the host's category bitmap in bytes * * Description: * Perform a label mapping to translate a CIPSO bitmap to the correct local * MLS category bitmap using the given DOI definition. Returns the minimum * size in bytes of the host bitmap on success, negative values otherwise. * */ static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def, const unsigned char *net_cat, u32 net_cat_len, unsigned char *host_cat, u32 host_cat_len) { u32 host_spot; u32 host_spot_max = 0; int net_spot = -1; u32 net_clen_bits = net_cat_len * 8; u32 host_clen_bits = host_cat_len * 8; u32 net_cat_size; u32 *net_cat_array; switch (doi_def->type) { case CIPSO_V4_MAP_PASS: if (net_cat_len > host_cat_len) return -EINVAL; memcpy(host_cat, net_cat, net_cat_len); return net_cat_len; case CIPSO_V4_MAP_STD: net_cat_size = doi_def->map.std->cat.cipso_size; net_cat_array = doi_def->map.std->cat.cipso; for (;;) { net_spot = cipso_v4_bitmap_walk(net_cat, net_clen_bits, net_spot + 1, 1); if (net_spot < 0) break; if (net_spot >= net_cat_size || net_cat_array[net_spot] >= CIPSO_V4_INV_CAT) return -EPERM; host_spot = net_cat_array[net_spot]; if (host_spot >= host_clen_bits) return -ENOSPC; cipso_v4_bitmap_setbit(host_cat, host_spot, 1); if (host_spot > host_spot_max) host_spot_max = host_spot; } if (net_spot == -2) return -EFAULT; if (++host_spot_max % 8) return host_spot_max / 8 + 1; return host_spot_max / 8; } return -EINVAL; } /* * Protocol Handling Functions */ #define CIPSO_V4_HDR_LEN 6 /** * cipso_v4_gentag_hdr - Generate a CIPSO option header * @doi_def: the DOI definition * @len: the total tag length in bytes * @buf: the CIPSO option buffer * * Description: * Write a CIPSO header into the beginning of @buffer. Return zero on success, * negative values on failure. * */ static int cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def, u32 len, unsigned char *buf) { if (CIPSO_V4_HDR_LEN + len > 40) return -ENOSPC; buf[0] = IPOPT_CIPSO; buf[1] = CIPSO_V4_HDR_LEN + len; *(u32 *)&buf[2] = htonl(doi_def->doi); return 0; } #define CIPSO_V4_TAG1_CAT_LEN 30 /** * cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1) * @doi_def: the DOI definition * @secattr: the security attributes * @buffer: the option buffer * @buffer_len: length of buffer in bytes * * Description: * Generate a CIPSO option using the restricted bitmap tag, tag type #1. The * actual buffer length may be larger than the indicated size due to * translation between host and network category bitmaps. Returns zero on * success, negative values on failure. * */ static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr, unsigned char **buffer, u32 *buffer_len) { int ret_val = -EPERM; unsigned char *buf = NULL; u32 buf_len; u32 level; if (secattr->mls_cat) { buf = kzalloc(CIPSO_V4_HDR_LEN + 4 + CIPSO_V4_TAG1_CAT_LEN, GFP_ATOMIC); if (buf == NULL) return -ENOMEM; ret_val = cipso_v4_map_cat_rbm_hton(doi_def, secattr->mls_cat, secattr->mls_cat_len, &buf[CIPSO_V4_HDR_LEN + 4], CIPSO_V4_TAG1_CAT_LEN); if (ret_val < 0) goto gentag_failure; /* This will send packets using the "optimized" format when * possibile as specified in section 3.4.2.6 of the * CIPSO draft. */ if (cipso_v4_rbm_optfmt && (ret_val > 0 && ret_val < 10)) ret_val = 10; buf_len = 4 + ret_val; } else { buf = kzalloc(CIPSO_V4_HDR_LEN + 4, GFP_ATOMIC); if (buf == NULL) return -ENOMEM; buf_len = 4; } ret_val = cipso_v4_map_lvl_hton(doi_def, secattr->mls_lvl, &level); if (ret_val != 0) goto gentag_failure; ret_val = cipso_v4_gentag_hdr(doi_def, buf_len, buf); if (ret_val != 0) goto gentag_failure; buf[CIPSO_V4_HDR_LEN] = 0x01; buf[CIPSO_V4_HDR_LEN + 1] = buf_len; buf[CIPSO_V4_HDR_LEN + 3] = level; *buffer = buf; *buffer_len = CIPSO_V4_HDR_LEN + buf_len; return 0; gentag_failure: kfree(buf); return ret_val; } /** * cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag * @doi_def: the DOI definition * @tag: the CIPSO tag * @secattr: the security attributes * * Description: * Parse a CIPSO restricted bitmap tag (tag type #1) and return the security * attributes in @secattr. Return zero on success, negatives values on * failure. * */ static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def, const unsigned char *tag, struct netlbl_lsm_secattr *secattr) { int ret_val; u8 tag_len = tag[1]; u32 level; ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level); if (ret_val != 0) return ret_val; secattr->mls_lvl = level; secattr->mls_lvl_vld = 1; if (tag_len > 4) { switch (doi_def->type) { case CIPSO_V4_MAP_PASS: secattr->mls_cat_len = tag_len - 4; break; case CIPSO_V4_MAP_STD: secattr->mls_cat_len = doi_def->map.std->cat.local_size; break; } secattr->mls_cat = kzalloc(secattr->mls_cat_len, GFP_ATOMIC); if (secattr->mls_cat == NULL) return -ENOMEM; ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def, &tag[4], tag_len - 4, secattr->mls_cat, secattr->mls_cat_len); if (ret_val < 0) { kfree(secattr->mls_cat); return ret_val; } secattr->mls_cat_len = ret_val; } return 0; } /** * cipso_v4_validate - Validate a CIPSO option * @option: the start of the option, on error it is set to point to the error * * Description: * This routine is called to validate a CIPSO option, it checks all of the * fields to ensure that they are at least valid, see the draft snippet below * for details. If the option is valid then a zero value is returned and * the value of @option is unchanged. If the option is invalid then a * non-zero value is returned and @option is adjusted to point to the * offending portion of the option. From the IETF draft ... * * "If any field within the CIPSO options, such as the DOI identifier, is not * recognized the IP datagram is discarded and an ICMP 'parameter problem' * (type 12) is generated and returned. The ICMP code field is set to 'bad * parameter' (code 0) and the pointer is set to the start of the CIPSO field * that is unrecognized." * */ int cipso_v4_validate(unsigned char **option) { unsigned char *opt = *option; unsigned char *tag; unsigned char opt_iter; unsigned char err_offset = 0; u8 opt_len; u8 tag_len; struct cipso_v4_doi *doi_def = NULL; u32 tag_iter; /* caller already checks for length values that are too large */ opt_len = opt[1]; if (opt_len < 8) { err_offset = 1; goto validate_return; } rcu_read_lock(); doi_def = cipso_v4_doi_getdef(ntohl(*((u32 *)&opt[2]))); if (doi_def == NULL) { err_offset = 2; goto validate_return_locked; } opt_iter = 6; tag = opt + opt_iter; while (opt_iter < opt_len) { for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];) if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID || ++tag_iter == CIPSO_V4_TAG_MAXCNT) { err_offset = opt_iter; goto validate_return_locked; } tag_len = tag[1]; if (tag_len > (opt_len - opt_iter)) { err_offset = opt_iter + 1; goto validate_return_locked; } switch (tag[0]) { case CIPSO_V4_TAG_RBITMAP: if (tag_len < 4) { err_offset = opt_iter + 1; goto validate_return_locked; } /* We are already going to do all the verification * necessary at the socket layer so from our point of * view it is safe to turn these checks off (and less * work), however, the CIPSO draft says we should do * all the CIPSO validations here but it doesn't * really specify _exactly_ what we need to validate * ... so, just make it a sysctl tunable. */ if (cipso_v4_rbm_strictvalid) { if (cipso_v4_map_lvl_valid(doi_def, tag[3]) < 0) { err_offset = opt_iter + 3; goto validate_return_locked; } if (tag_len > 4 && cipso_v4_map_cat_rbm_valid(doi_def, &tag[4], tag_len - 4) < 0) { err_offset = opt_iter + 4; goto validate_return_locked; } } break; default: err_offset = opt_iter; goto validate_return_locked; } tag += tag_len; opt_iter += tag_len; } validate_return_locked: rcu_read_unlock(); validate_return: *option = opt + err_offset; return err_offset; } /** * cipso_v4_error - Send the correct reponse for a bad packet * @skb: the packet * @error: the error code * @gateway: CIPSO gateway flag * * Description: * Based on the error code given in @error, send an ICMP error message back to * the originating host. From the IETF draft ... * * "If the contents of the CIPSO [option] are valid but the security label is * outside of the configured host or port label range, the datagram is * discarded and an ICMP 'destination unreachable' (type 3) is generated and * returned. The code field of the ICMP is set to 'communication with * destination network administratively prohibited' (code 9) or to * 'communication with destination host administratively prohibited' * (code 10). The value of the code is dependent on whether the originator * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The * recipient of the ICMP message MUST be able to handle either value. The * same procedure is performed if a CIPSO [option] can not be added to an * IP packet because it is too large to fit in the IP options area." * * "If the error is triggered by receipt of an ICMP message, the message is * discarded and no response is permitted (consistent with general ICMP * processing rules)." * */ void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway) { if (skb->nh.iph->protocol == IPPROTO_ICMP || error != -EACCES) return; if (gateway) icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0); else icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0); } /** * cipso_v4_socket_setattr - Add a CIPSO option to a socket * @sock: the socket * @doi_def: the CIPSO DOI to use * @secattr: the specific security attributes of the socket * * Description: * Set the CIPSO option on the given socket using the DOI definition and * security attributes passed to the function. This function requires * exclusive access to @sock->sk, which means it either needs to be in the * process of being created or locked via lock_sock(sock->sk). Returns zero on * success and negative values on failure. * */ int cipso_v4_socket_setattr(const struct socket *sock, const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr) { int ret_val = -EPERM; u32 iter; unsigned char *buf = NULL; u32 buf_len = 0; u32 opt_len; struct ip_options *opt = NULL; struct sock *sk; struct inet_sock *sk_inet; struct inet_connection_sock *sk_conn; /* In the case of sock_create_lite(), the sock->sk field is not * defined yet but it is not a problem as the only users of these * "lite" PF_INET sockets are functions which do an accept() call * afterwards so we will label the socket as part of the accept(). */ sk = sock->sk; if (sk == NULL) return 0; /* XXX - This code assumes only one tag per CIPSO option which isn't * really a good assumption to make but since we only support the MAC * tags right now it is a safe assumption. */ iter = 0; do { switch (doi_def->tags[iter]) { case CIPSO_V4_TAG_RBITMAP: ret_val = cipso_v4_gentag_rbm(doi_def, secattr, &buf, &buf_len); break; default: ret_val = -EPERM; goto socket_setattr_failure; } iter++; } while (ret_val != 0 && iter < CIPSO_V4_TAG_MAXCNT && doi_def->tags[iter] != CIPSO_V4_TAG_INVALID); if (ret_val != 0) goto socket_setattr_failure; /* We can't use ip_options_get() directly because it makes a call to * ip_options_get_alloc() which allocates memory with GFP_KERNEL and * we won't always have CAP_NET_RAW even though we _always_ want to * set the IPOPT_CIPSO option. */ opt_len = (buf_len + 3) & ~3; opt = kzalloc(sizeof(*opt) + opt_len, GFP_ATOMIC); if (opt == NULL) { ret_val = -ENOMEM; goto socket_setattr_failure; } memcpy(opt->__data, buf, buf_len); opt->optlen = opt_len; opt->is_data = 1; opt->cipso = sizeof(struct iphdr); kfree(buf); buf = NULL; sk_inet = inet_sk(sk); if (sk_inet->is_icsk) { sk_conn = inet_csk(sk); if (sk_inet->opt) sk_conn->icsk_ext_hdr_len -= sk_inet->opt->optlen; sk_conn->icsk_ext_hdr_len += opt->optlen; sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); } opt = xchg(&sk_inet->opt, opt); kfree(opt); return 0; socket_setattr_failure: kfree(buf); kfree(opt); return ret_val; } /** * cipso_v4_sock_getattr - Get the security attributes from a sock * @sk: the sock * @secattr: the security attributes * * Description: * Query @sk to see if there is a CIPSO option attached to the sock and if * there is return the CIPSO security attributes in @secattr. This function * requires that @sk be locked, or privately held, but it does not do any * locking itself. Returns zero on success and negative values on failure. * */ int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr) { int ret_val = -ENOMSG; struct inet_sock *sk_inet; unsigned char *cipso_ptr; u32 doi; struct cipso_v4_doi *doi_def; sk_inet = inet_sk(sk); if (sk_inet->opt == NULL || sk_inet->opt->cipso == 0) return -ENOMSG; cipso_ptr = sk_inet->opt->__data + sk_inet->opt->cipso - sizeof(struct iphdr); ret_val = cipso_v4_cache_check(cipso_ptr, cipso_ptr[1], secattr); if (ret_val == 0) return ret_val; doi = ntohl(*(u32 *)&cipso_ptr[2]); rcu_read_lock(); doi_def = cipso_v4_doi_getdef(doi); if (doi_def == NULL) { rcu_read_unlock(); return -ENOMSG; } switch (cipso_ptr[6]) { case CIPSO_V4_TAG_RBITMAP: ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso_ptr[6], secattr); break; } rcu_read_unlock(); return ret_val; } /** * cipso_v4_socket_getattr - Get the security attributes from a socket * @sock: the socket * @secattr: the security attributes * * Description: * Query @sock to see if there is a CIPSO option attached to the socket and if * there is return the CIPSO security attributes in @secattr. Returns zero on * success and negative values on failure. * */ int cipso_v4_socket_getattr(const struct socket *sock, struct netlbl_lsm_secattr *secattr) { int ret_val; lock_sock(sock->sk); ret_val = cipso_v4_sock_getattr(sock->sk, secattr); release_sock(sock->sk); return ret_val; } /** * cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option * @skb: the packet * @secattr: the security attributes * * Description: * Parse the given packet's CIPSO option and return the security attributes. * Returns zero on success and negative values on failure. * */ int cipso_v4_skbuff_getattr(const struct sk_buff *skb, struct netlbl_lsm_secattr *secattr) { int ret_val = -ENOMSG; unsigned char *cipso_ptr; u32 doi; struct cipso_v4_doi *doi_def; if (!CIPSO_V4_OPTEXIST(skb)) return -ENOMSG; cipso_ptr = CIPSO_V4_OPTPTR(skb); if (cipso_v4_cache_check(cipso_ptr, cipso_ptr[1], secattr) == 0) return 0; doi = ntohl(*(u32 *)&cipso_ptr[2]); rcu_read_lock(); doi_def = cipso_v4_doi_getdef(doi); if (doi_def == NULL) goto skbuff_getattr_return; switch (cipso_ptr[6]) { case CIPSO_V4_TAG_RBITMAP: ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso_ptr[6], secattr); break; } skbuff_getattr_return: rcu_read_unlock(); return ret_val; } /* * Setup Functions */ /** * cipso_v4_init - Initialize the CIPSO module * * Description: * Initialize the CIPSO module and prepare it for use. Returns zero on success * and negative values on failure. * */ static int __init cipso_v4_init(void) { int ret_val; ret_val = cipso_v4_cache_init(); if (ret_val != 0) panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n", ret_val); return 0; } subsys_initcall(cipso_v4_init);