/* * 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. 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. * * The CIPSO draft specification can be found in the kernel's Documentation * directory as well as the following URL: * http://tools.ietf.org/id/draft-ietf-cipso-ipsecurity-01.txt * The FIPS-188 specification can be found at the following URL: * http://www.itl.nist.gov/fipspubs/fip188.htm * * Author: Paul Moore <paul.moore@hp.com> * */ /* * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 * * 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, see <http://www.gnu.org/licenses/>. * */ #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 <linux/audit.h> #include <linux/slab.h> #include <net/ip.h> #include <net/icmp.h> #include <net/tcp.h> #include <net/netlabel.h> #include <net/cipso_ipv4.h> #include <linux/atomic.h> #include <linux/bug.h> #include <asm/unaligned.h> /* List of available DOI definitions */ /* 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 LIST_HEAD(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; /* Restricted bitmap (tag #1) flags */ int cipso_v4_rbm_optfmt = 0; int cipso_v4_rbm_strictvalid = 1; /* * Protocol Constants */ /* Maximum size of the CIPSO IP option, derived from the fact that the maximum * IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */ #define CIPSO_V4_OPT_LEN_MAX 40 /* Length of the base CIPSO option, this includes the option type (1 byte), the * option length (1 byte), and the DOI (4 bytes). */ #define CIPSO_V4_HDR_LEN 6 /* Base length of the restrictive category bitmap tag (tag #1). */ #define CIPSO_V4_TAG_RBM_BLEN 4 /* Base length of the enumerated category tag (tag #2). */ #define CIPSO_V4_TAG_ENUM_BLEN 4 /* Base length of the ranged categories bitmap tag (tag #5). */ #define CIPSO_V4_TAG_RNG_BLEN 4 /* The maximum number of category ranges permitted in the ranged category tag * (tag #5). You may note that the IETF draft states that the maximum number * of category ranges is 7, but if the low end of the last category range is * zero then it is possible to fit 8 category ranges because the zero should * be omitted. */ #define CIPSO_V4_TAG_RNG_CAT_MAX 8 /* Base length of the local tag (non-standard tag). * Tag definition (may change between kernel versions) * * 0 8 16 24 32 * +----------+----------+----------+----------+ * | 10000000 | 00000110 | 32-bit secid value | * +----------+----------+----------+----------+ * | in (host byte order)| * +----------+----------+ * */ #define CIPSO_V4_TAG_LOC_BLEN 6 /* * Helper Functions */ /** * 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 __init 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) 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); } } /** * 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_BUCKETS - 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; secattr->flags |= NETLBL_SECATTR_CACHE; secattr->type = NETLBL_NLTYPE_CIPSOV4; if (!prev_entry) { 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 unsigned char *cipso_ptr, 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; u32 cipso_ptr_len; if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0) return 0; cipso_ptr_len = cipso_ptr[1]; entry = kzalloc(sizeof(*entry), GFP_ATOMIC); if (!entry) return -ENOMEM; entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC); if (!entry->key) { ret_val = -ENOMEM; goto cache_add_failure; } 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_BUCKETS - 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 responsible 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 && atomic_read(&iter->refcount)) return iter; return NULL; } /** * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine * @doi_def: the DOI structure * @audit_info: NetLabel audit information * * 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, struct netlbl_audit *audit_info) { int ret_val = -EINVAL; u32 iter; u32 doi; u32 doi_type; struct audit_buffer *audit_buf; doi = doi_def->doi; doi_type = doi_def->type; if (doi_def->doi == CIPSO_V4_DOI_UNKNOWN) goto doi_add_return; for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) { switch (doi_def->tags[iter]) { case CIPSO_V4_TAG_RBITMAP: break; case CIPSO_V4_TAG_RANGE: case CIPSO_V4_TAG_ENUM: if (doi_def->type != CIPSO_V4_MAP_PASS) goto doi_add_return; break; case CIPSO_V4_TAG_LOCAL: if (doi_def->type != CIPSO_V4_MAP_LOCAL) goto doi_add_return; break; case CIPSO_V4_TAG_INVALID: if (iter == 0) goto doi_add_return; break; default: goto doi_add_return; } } atomic_set(&doi_def->refcount, 1); spin_lock(&cipso_v4_doi_list_lock); if (cipso_v4_doi_search(doi_def->doi)) { spin_unlock(&cipso_v4_doi_list_lock); ret_val = -EEXIST; goto doi_add_return; } list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list); spin_unlock(&cipso_v4_doi_list_lock); ret_val = 0; doi_add_return: audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_ADD, audit_info); if (audit_buf) { const char *type_str; switch (doi_type) { case CIPSO_V4_MAP_TRANS: type_str = "trans"; break; case CIPSO_V4_MAP_PASS: type_str = "pass"; break; case CIPSO_V4_MAP_LOCAL: type_str = "local"; break; default: type_str = "(unknown)"; } audit_log_format(audit_buf, " cipso_doi=%u cipso_type=%s res=%u", doi, type_str, ret_val == 0 ? 1 : 0); audit_log_end(audit_buf); } return ret_val; } /** * cipso_v4_doi_free - Frees a DOI definition * @doi_def: the DOI definition * * Description: * This function frees all of the memory associated with a DOI definition. * */ void cipso_v4_doi_free(struct cipso_v4_doi *doi_def) { if (!doi_def) return; switch (doi_def->type) { case CIPSO_V4_MAP_TRANS: kfree(doi_def->map.std->lvl.cipso); kfree(doi_def->map.std->lvl.local); kfree(doi_def->map.std->cat.cipso); kfree(doi_def->map.std->cat.local); break; } kfree(doi_def); } /** * cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer * @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 the DOI definition can be released * safely. * */ static void cipso_v4_doi_free_rcu(struct rcu_head *entry) { struct cipso_v4_doi *doi_def; doi_def = container_of(entry, struct cipso_v4_doi, rcu); cipso_v4_doi_free(doi_def); } /** * 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 * * Description: * Removes a DOI definition from the CIPSO engine. 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) { int ret_val; struct cipso_v4_doi *doi_def; struct audit_buffer *audit_buf; spin_lock(&cipso_v4_doi_list_lock); doi_def = cipso_v4_doi_search(doi); if (!doi_def) { spin_unlock(&cipso_v4_doi_list_lock); ret_val = -ENOENT; goto doi_remove_return; } if (!atomic_dec_and_test(&doi_def->refcount)) { spin_unlock(&cipso_v4_doi_list_lock); ret_val = -EBUSY; goto doi_remove_return; } list_del_rcu(&doi_def->list); spin_unlock(&cipso_v4_doi_list_lock); cipso_v4_cache_invalidate(); call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); ret_val = 0; doi_remove_return: audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info); if (audit_buf) { audit_log_format(audit_buf, " cipso_doi=%u res=%u", doi, ret_val == 0 ? 1 : 0); audit_log_end(audit_buf); } return ret_val; } /** * cipso_v4_doi_getdef - Returns a reference 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 and the DOI * definition reference count is decremented when the caller is done. * */ struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi) { struct cipso_v4_doi *doi_def; rcu_read_lock(); doi_def = cipso_v4_doi_search(doi); if (!doi_def) goto doi_getdef_return; if (!atomic_inc_not_zero(&doi_def->refcount)) doi_def = NULL; doi_getdef_return: rcu_read_unlock(); return doi_def; } /** * cipso_v4_doi_putdef - Releases a reference for the given DOI definition * @doi_def: the DOI definition * * Description: * Releases a DOI definition reference obtained from cipso_v4_doi_getdef(). * */ void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def) { if (!doi_def) return; if (!atomic_dec_and_test(&doi_def->refcount)) return; spin_lock(&cipso_v4_doi_list_lock); list_del_rcu(&doi_def->list); spin_unlock(&cipso_v4_doi_list_lock); cipso_v4_cache_invalidate(); call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu); } /** * 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 (atomic_read(&iter_doi->refcount) > 0) { 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; } /* * 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_TRANS: 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_TRANS: if (host_lvl < doi_def->map.std->lvl.local_size && doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) { *net_lvl = doi_def->map.std->lvl.local[host_lvl]; return 0; } return -EPERM; } 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_TRANS: 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; } return -EPERM; } 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_TRANS: cipso_cat_size = doi_def->map.std->cat.cipso_size; cipso_array = doi_def->map.std->cat.cipso; for (;;) { cat = netlbl_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 * @secattr: the security attributes * @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 struct netlbl_lsm_secattr *secattr, unsigned char *net_cat, u32 net_cat_len) { int host_spot = -1; u32 net_spot = CIPSO_V4_INV_CAT; u32 net_spot_max = 0; u32 net_clen_bits = net_cat_len * 8; u32 host_cat_size = 0; u32 *host_cat_array = NULL; if (doi_def->type == CIPSO_V4_MAP_TRANS) { host_cat_size = doi_def->map.std->cat.local_size; host_cat_array = doi_def->map.std->cat.local; } for (;;) { host_spot = netlbl_catmap_walk(secattr->attr.mls.cat, host_spot + 1); if (host_spot < 0) break; switch (doi_def->type) { case CIPSO_V4_MAP_PASS: net_spot = host_spot; break; case CIPSO_V4_MAP_TRANS: if (host_spot >= host_cat_size) return -EPERM; net_spot = host_cat_array[host_spot]; if (net_spot >= CIPSO_V4_INV_CAT) return -EPERM; break; } if (net_spot >= net_clen_bits) return -ENOSPC; netlbl_bitmap_setbit(net_cat, net_spot, 1); if (net_spot > net_spot_max) net_spot_max = net_spot; } if (++net_spot_max % 8) return net_spot_max / 8 + 1; return net_spot_max / 8; } /** * 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 * @secattr: the security attributes * * Description: * Perform a label mapping to translate a CIPSO bitmap to the correct local * MLS category bitmap using the given DOI definition. Returns zero on * success, negative values on failure. * */ static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def, const unsigned char *net_cat, u32 net_cat_len, struct netlbl_lsm_secattr *secattr) { int ret_val; int net_spot = -1; u32 host_spot = CIPSO_V4_INV_CAT; u32 net_clen_bits = net_cat_len * 8; u32 net_cat_size = 0; u32 *net_cat_array = NULL; if (doi_def->type == CIPSO_V4_MAP_TRANS) { net_cat_size = doi_def->map.std->cat.cipso_size; net_cat_array = doi_def->map.std->cat.cipso; } for (;;) { net_spot = netlbl_bitmap_walk(net_cat, net_clen_bits, net_spot + 1, 1); if (net_spot < 0) { if (net_spot == -2) return -EFAULT; return 0; } switch (doi_def->type) { case CIPSO_V4_MAP_PASS: host_spot = net_spot; break; case CIPSO_V4_MAP_TRANS: if (net_spot >= net_cat_size) return -EPERM; host_spot = net_cat_array[net_spot]; if (host_spot >= CIPSO_V4_INV_CAT) return -EPERM; break; } ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat, host_spot, GFP_ATOMIC); if (ret_val != 0) return ret_val; } return -EINVAL; } /** * cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid * @doi_def: the DOI definition * @enumcat: category list * @enumcat_len: length of the category list in bytes * * Description: * Checks the given categories against the given DOI definition and returns a * negative value if any of the categories do not have a valid mapping and a * zero value if all of the categories are valid. * */ static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def, const unsigned char *enumcat, u32 enumcat_len) { u16 cat; int cat_prev = -1; u32 iter; if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01) return -EFAULT; for (iter = 0; iter < enumcat_len; iter += 2) { cat = get_unaligned_be16(&enumcat[iter]); if (cat <= cat_prev) return -EFAULT; cat_prev = cat; } return 0; } /** * cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network * @doi_def: the DOI definition * @secattr: the security attributes * @net_cat: the zero'd out category list in network/CIPSO format * @net_cat_len: the length of the CIPSO category list in bytes * * Description: * Perform a label mapping to translate a local MLS category bitmap to the * correct CIPSO category list using the given DOI definition. Returns the * size in bytes of the network category bitmap on success, negative values * otherwise. * */ static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr, unsigned char *net_cat, u32 net_cat_len) { int cat = -1; u32 cat_iter = 0; for (;;) { cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1); if (cat < 0) break; if ((cat_iter + 2) > net_cat_len) return -ENOSPC; *((__be16 *)&net_cat[cat_iter]) = htons(cat); cat_iter += 2; } return cat_iter; } /** * cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host * @doi_def: the DOI definition * @net_cat: the category list in network/CIPSO format * @net_cat_len: the length of the CIPSO bitmap in bytes * @secattr: the security attributes * * Description: * Perform a label mapping to translate a CIPSO category list to the correct * local MLS category bitmap using the given DOI definition. Returns zero on * success, negative values on failure. * */ static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def, const unsigned char *net_cat, u32 net_cat_len, struct netlbl_lsm_secattr *secattr) { int ret_val; u32 iter; for (iter = 0; iter < net_cat_len; iter += 2) { ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat, get_unaligned_be16(&net_cat[iter]), GFP_ATOMIC); if (ret_val != 0) return ret_val; } return 0; } /** * cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid * @doi_def: the DOI definition * @rngcat: category list * @rngcat_len: length of the category list in bytes * * Description: * Checks the given categories against the given DOI definition and returns a * negative value if any of the categories do not have a valid mapping and a * zero value if all of the categories are valid. * */ static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def, const unsigned char *rngcat, u32 rngcat_len) { u16 cat_high; u16 cat_low; u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1; u32 iter; if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01) return -EFAULT; for (iter = 0; iter < rngcat_len; iter += 4) { cat_high = get_unaligned_be16(&rngcat[iter]); if ((iter + 4) <= rngcat_len) cat_low = get_unaligned_be16(&rngcat[iter + 2]); else cat_low = 0; if (cat_high > cat_prev) return -EFAULT; cat_prev = cat_low; } return 0; } /** * cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network * @doi_def: the DOI definition * @secattr: the security attributes * @net_cat: the zero'd out category list in network/CIPSO format * @net_cat_len: the length of the CIPSO category list in bytes * * Description: * Perform a label mapping to translate a local MLS category bitmap to the * correct CIPSO category list using the given DOI definition. Returns the * size in bytes of the network category bitmap on success, negative values * otherwise. * */ static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr, unsigned char *net_cat, u32 net_cat_len) { int iter = -1; u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2]; u32 array_cnt = 0; u32 cat_size = 0; /* make sure we don't overflow the 'array[]' variable */ if (net_cat_len > (CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN)) return -ENOSPC; for (;;) { iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1); if (iter < 0) break; cat_size += (iter == 0 ? 0 : sizeof(u16)); if (cat_size > net_cat_len) return -ENOSPC; array[array_cnt++] = iter; iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter); if (iter < 0) return -EFAULT; cat_size += sizeof(u16); if (cat_size > net_cat_len) return -ENOSPC; array[array_cnt++] = iter; } for (iter = 0; array_cnt > 0;) { *((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]); iter += 2; array_cnt--; if (array[array_cnt] != 0) { *((__be16 *)&net_cat[iter]) = htons(array[array_cnt]); iter += 2; } } return cat_size; } /** * cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host * @doi_def: the DOI definition * @net_cat: the category list in network/CIPSO format * @net_cat_len: the length of the CIPSO bitmap in bytes * @secattr: the security attributes * * Description: * Perform a label mapping to translate a CIPSO category list to the correct * local MLS category bitmap using the given DOI definition. Returns zero on * success, negative values on failure. * */ static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def, const unsigned char *net_cat, u32 net_cat_len, struct netlbl_lsm_secattr *secattr) { int ret_val; u32 net_iter; u16 cat_low; u16 cat_high; for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) { cat_high = get_unaligned_be16(&net_cat[net_iter]); if ((net_iter + 4) <= net_cat_len) cat_low = get_unaligned_be16(&net_cat[net_iter + 2]); else cat_low = 0; ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat, cat_low, cat_high, GFP_ATOMIC); if (ret_val != 0) return ret_val; } return 0; } /* * Protocol Handling Functions */ /** * cipso_v4_gentag_hdr - Generate a CIPSO option header * @doi_def: the DOI definition * @len: the total tag length in bytes, not including this header * @buf: the CIPSO option buffer * * Description: * Write a CIPSO header into the beginning of @buffer. * */ static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def, unsigned char *buf, u32 len) { buf[0] = IPOPT_CIPSO; buf[1] = CIPSO_V4_HDR_LEN + len; *(__be32 *)&buf[2] = htonl(doi_def->doi); } /** * 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 the size of * the tag 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; u32 tag_len; u32 level; if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0) return -EPERM; ret_val = cipso_v4_map_lvl_hton(doi_def, secattr->attr.mls.lvl, &level); if (ret_val != 0) return ret_val; if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { ret_val = cipso_v4_map_cat_rbm_hton(doi_def, secattr, &buffer[4], buffer_len - 4); if (ret_val < 0) return ret_val; /* This will send packets using the "optimized" format when * possible as specified in section 3.4.2.6 of the * CIPSO draft. */ if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10) tag_len = 14; else tag_len = 4 + ret_val; } else tag_len = 4; buffer[0] = CIPSO_V4_TAG_RBITMAP; buffer[1] = tag_len; buffer[3] = level; return tag_len; } /** * 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->attr.mls.lvl = level; secattr->flags |= NETLBL_SECATTR_MLS_LVL; if (tag_len > 4) { ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def, &tag[4], tag_len - 4, secattr); if (ret_val != 0) { netlbl_catmap_free(secattr->attr.mls.cat); return ret_val; } secattr->flags |= NETLBL_SECATTR_MLS_CAT; } return 0; } /** * cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2) * @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 enumerated tag, tag type #2. Returns the * size of the tag on success, negative values on failure. * */ static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr, unsigned char *buffer, u32 buffer_len) { int ret_val; u32 tag_len; u32 level; if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) return -EPERM; ret_val = cipso_v4_map_lvl_hton(doi_def, secattr->attr.mls.lvl, &level); if (ret_val != 0) return ret_val; if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { ret_val = cipso_v4_map_cat_enum_hton(doi_def, secattr, &buffer[4], buffer_len - 4); if (ret_val < 0) return ret_val; tag_len = 4 + ret_val; } else tag_len = 4; buffer[0] = CIPSO_V4_TAG_ENUM; buffer[1] = tag_len; buffer[3] = level; return tag_len; } /** * cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag * @doi_def: the DOI definition * @tag: the CIPSO tag * @secattr: the security attributes * * Description: * Parse a CIPSO enumerated tag (tag type #2) and return the security * attributes in @secattr. Return zero on success, negatives values on * failure. * */ static int cipso_v4_parsetag_enum(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->attr.mls.lvl = level; secattr->flags |= NETLBL_SECATTR_MLS_LVL; if (tag_len > 4) { ret_val = cipso_v4_map_cat_enum_ntoh(doi_def, &tag[4], tag_len - 4, secattr); if (ret_val != 0) { netlbl_catmap_free(secattr->attr.mls.cat); return ret_val; } secattr->flags |= NETLBL_SECATTR_MLS_CAT; } return 0; } /** * cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5) * @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 ranged tag, tag type #5. Returns the * size of the tag on success, negative values on failure. * */ static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr, unsigned char *buffer, u32 buffer_len) { int ret_val; u32 tag_len; u32 level; if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL)) return -EPERM; ret_val = cipso_v4_map_lvl_hton(doi_def, secattr->attr.mls.lvl, &level); if (ret_val != 0) return ret_val; if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { ret_val = cipso_v4_map_cat_rng_hton(doi_def, secattr, &buffer[4], buffer_len - 4); if (ret_val < 0) return ret_val; tag_len = 4 + ret_val; } else tag_len = 4; buffer[0] = CIPSO_V4_TAG_RANGE; buffer[1] = tag_len; buffer[3] = level; return tag_len; } /** * cipso_v4_parsetag_rng - Parse a CIPSO ranged tag * @doi_def: the DOI definition * @tag: the CIPSO tag * @secattr: the security attributes * * Description: * Parse a CIPSO ranged tag (tag type #5) and return the security attributes * in @secattr. Return zero on success, negatives values on failure. * */ static int cipso_v4_parsetag_rng(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->attr.mls.lvl = level; secattr->flags |= NETLBL_SECATTR_MLS_LVL; if (tag_len > 4) { ret_val = cipso_v4_map_cat_rng_ntoh(doi_def, &tag[4], tag_len - 4, secattr); if (ret_val != 0) { netlbl_catmap_free(secattr->attr.mls.cat); return ret_val; } secattr->flags |= NETLBL_SECATTR_MLS_CAT; } return 0; } /** * cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard) * @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 local tag. Returns the size of the tag * on success, negative values on failure. * */ static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr, unsigned char *buffer, u32 buffer_len) { if (!(secattr->flags & NETLBL_SECATTR_SECID)) return -EPERM; buffer[0] = CIPSO_V4_TAG_LOCAL; buffer[1] = CIPSO_V4_TAG_LOC_BLEN; *(u32 *)&buffer[2] = secattr->attr.secid; return CIPSO_V4_TAG_LOC_BLEN; } /** * cipso_v4_parsetag_loc - Parse a CIPSO local tag * @doi_def: the DOI definition * @tag: the CIPSO tag * @secattr: the security attributes * * Description: * Parse a CIPSO local tag and return the security attributes in @secattr. * Return zero on success, negatives values on failure. * */ static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def, const unsigned char *tag, struct netlbl_lsm_secattr *secattr) { secattr->attr.secid = *(u32 *)&tag[2]; secattr->flags |= NETLBL_SECATTR_SECID; return 0; } /** * cipso_v4_optptr - Find the CIPSO option in the packet * @skb: the packet * * Description: * Parse the packet's IP header looking for a CIPSO option. Returns a pointer * to the start of the CIPSO option on success, NULL if one if not found. * */ unsigned char *cipso_v4_optptr(const struct sk_buff *skb) { const struct iphdr *iph = ip_hdr(skb); unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]); int optlen; int taglen; for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) { if (optptr[0] == IPOPT_CIPSO) return optptr; taglen = optptr[1]; optlen -= taglen; optptr += taglen; } return NULL; } /** * 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(const struct sk_buff *skb, 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_search(get_unaligned_be32(&opt[2])); if (!doi_def) { err_offset = 2; goto validate_return_locked; } opt_iter = CIPSO_V4_HDR_LEN; 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 < CIPSO_V4_TAG_RBM_BLEN) { 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 > CIPSO_V4_TAG_RBM_BLEN && cipso_v4_map_cat_rbm_valid(doi_def, &tag[4], tag_len - 4) < 0) { err_offset = opt_iter + 4; goto validate_return_locked; } } break; case CIPSO_V4_TAG_ENUM: if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) { err_offset = opt_iter + 1; goto validate_return_locked; } if (cipso_v4_map_lvl_valid(doi_def, tag[3]) < 0) { err_offset = opt_iter + 3; goto validate_return_locked; } if (tag_len > CIPSO_V4_TAG_ENUM_BLEN && cipso_v4_map_cat_enum_valid(doi_def, &tag[4], tag_len - 4) < 0) { err_offset = opt_iter + 4; goto validate_return_locked; } break; case CIPSO_V4_TAG_RANGE: if (tag_len < CIPSO_V4_TAG_RNG_BLEN) { err_offset = opt_iter + 1; goto validate_return_locked; } if (cipso_v4_map_lvl_valid(doi_def, tag[3]) < 0) { err_offset = opt_iter + 3; goto validate_return_locked; } if (tag_len > CIPSO_V4_TAG_RNG_BLEN && cipso_v4_map_cat_rng_valid(doi_def, &tag[4], tag_len - 4) < 0) { err_offset = opt_iter + 4; goto validate_return_locked; } break; case CIPSO_V4_TAG_LOCAL: /* This is a non-standard tag that we only allow for * local connections, so if the incoming interface is * not the loopback device drop the packet. Further, * there is no legitimate reason for setting this from * userspace so reject it if skb is NULL. */ if (!skb || !(skb->dev->flags & IFF_LOOPBACK)) { err_offset = opt_iter; goto validate_return_locked; } if (tag_len != CIPSO_V4_TAG_LOC_BLEN) { err_offset = opt_iter + 1; 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 response 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 (ip_hdr(skb)->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_genopt - Generate a CIPSO option * @buf: the option buffer * @buf_len: the size of opt_buf * @doi_def: the CIPSO DOI to use * @secattr: the security attributes * * Description: * Generate a CIPSO option using the DOI definition and security attributes * passed to the function. Returns the length of the option on success and * negative values on failure. * */ static int cipso_v4_genopt(unsigned char *buf, u32 buf_len, const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr) { int ret_val; u32 iter; if (buf_len <= CIPSO_V4_HDR_LEN) return -ENOSPC; /* 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 { memset(buf, 0, buf_len); switch (doi_def->tags[iter]) { case CIPSO_V4_TAG_RBITMAP: ret_val = cipso_v4_gentag_rbm(doi_def, secattr, &buf[CIPSO_V4_HDR_LEN], buf_len - CIPSO_V4_HDR_LEN); break; case CIPSO_V4_TAG_ENUM: ret_val = cipso_v4_gentag_enum(doi_def, secattr, &buf[CIPSO_V4_HDR_LEN], buf_len - CIPSO_V4_HDR_LEN); break; case CIPSO_V4_TAG_RANGE: ret_val = cipso_v4_gentag_rng(doi_def, secattr, &buf[CIPSO_V4_HDR_LEN], buf_len - CIPSO_V4_HDR_LEN); break; case CIPSO_V4_TAG_LOCAL: ret_val = cipso_v4_gentag_loc(doi_def, secattr, &buf[CIPSO_V4_HDR_LEN], buf_len - CIPSO_V4_HDR_LEN); break; default: return -EPERM; } iter++; } while (ret_val < 0 && iter < CIPSO_V4_TAG_MAXCNT && doi_def->tags[iter] != CIPSO_V4_TAG_INVALID); if (ret_val < 0) return ret_val; cipso_v4_gentag_hdr(doi_def, buf, ret_val); return CIPSO_V4_HDR_LEN + ret_val; } /** * cipso_v4_sock_setattr - Add a CIPSO option to a socket * @sk: 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 @sk, which means it either needs to be in the * process of being created or locked. Returns zero on success and negative * values on failure. * */ int cipso_v4_sock_setattr(struct sock *sk, const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr) { int ret_val = -EPERM; unsigned char *buf = NULL; u32 buf_len; u32 opt_len; struct ip_options_rcu *old, *opt = NULL; 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(). */ if (!sk) return 0; /* We allocate the maximum CIPSO option size here so we are probably * being a little wasteful, but it makes our life _much_ easier later * on and after all we are only talking about 40 bytes. */ buf_len = CIPSO_V4_OPT_LEN_MAX; buf = kmalloc(buf_len, GFP_ATOMIC); if (!buf) { ret_val = -ENOMEM; goto socket_setattr_failure; } ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); if (ret_val < 0) goto socket_setattr_failure; buf_len = ret_val; /* 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) { ret_val = -ENOMEM; goto socket_setattr_failure; } memcpy(opt->opt.__data, buf, buf_len); opt->opt.optlen = opt_len; opt->opt.cipso = sizeof(struct iphdr); kfree(buf); buf = NULL; sk_inet = inet_sk(sk); old = rcu_dereference_protected(sk_inet->inet_opt, lockdep_sock_is_held(sk)); if (sk_inet->is_icsk) { sk_conn = inet_csk(sk); if (old) sk_conn->icsk_ext_hdr_len -= old->opt.optlen; sk_conn->icsk_ext_hdr_len += opt->opt.optlen; sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); } rcu_assign_pointer(sk_inet->inet_opt, opt); if (old) kfree_rcu(old, rcu); return 0; socket_setattr_failure: kfree(buf); kfree(opt); return ret_val; } /** * cipso_v4_req_setattr - Add a CIPSO option to a connection request socket * @req: the connection request 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. Returns zero on success and * negative values on failure. * */ int cipso_v4_req_setattr(struct request_sock *req, const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr) { int ret_val = -EPERM; unsigned char *buf = NULL; u32 buf_len; u32 opt_len; struct ip_options_rcu *opt = NULL; struct inet_request_sock *req_inet; /* We allocate the maximum CIPSO option size here so we are probably * being a little wasteful, but it makes our life _much_ easier later * on and after all we are only talking about 40 bytes. */ buf_len = CIPSO_V4_OPT_LEN_MAX; buf = kmalloc(buf_len, GFP_ATOMIC); if (!buf) { ret_val = -ENOMEM; goto req_setattr_failure; } ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); if (ret_val < 0) goto req_setattr_failure; buf_len = ret_val; /* 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) { ret_val = -ENOMEM; goto req_setattr_failure; } memcpy(opt->opt.__data, buf, buf_len); opt->opt.optlen = opt_len; opt->opt.cipso = sizeof(struct iphdr); kfree(buf); buf = NULL; req_inet = inet_rsk(req); opt = xchg(&req_inet->opt, opt); if (opt) kfree_rcu(opt, rcu); return 0; req_setattr_failure: kfree(buf); kfree(opt); return ret_val; } /** * cipso_v4_delopt - Delete the CIPSO option from a set of IP options * @opt_ptr: IP option pointer * * Description: * Deletes the CIPSO IP option from a set of IP options and makes the necessary * adjustments to the IP option structure. Returns zero on success, negative * values on failure. * */ static int cipso_v4_delopt(struct ip_options_rcu **opt_ptr) { int hdr_delta = 0; struct ip_options_rcu *opt = *opt_ptr; if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) { u8 cipso_len; u8 cipso_off; unsigned char *cipso_ptr; int iter; int optlen_new; cipso_off = opt->opt.cipso - sizeof(struct iphdr); cipso_ptr = &opt->opt.__data[cipso_off]; cipso_len = cipso_ptr[1]; if (opt->opt.srr > opt->opt.cipso) opt->opt.srr -= cipso_len; if (opt->opt.rr > opt->opt.cipso) opt->opt.rr -= cipso_len; if (opt->opt.ts > opt->opt.cipso) opt->opt.ts -= cipso_len; if (opt->opt.router_alert > opt->opt.cipso) opt->opt.router_alert -= cipso_len; opt->opt.cipso = 0; memmove(cipso_ptr, cipso_ptr + cipso_len, opt->opt.optlen - cipso_off - cipso_len); /* determining the new total option length is tricky because of * the padding necessary, the only thing i can think to do at * this point is walk the options one-by-one, skipping the * padding at the end to determine the actual option size and * from there we can determine the new total option length */ iter = 0; optlen_new = 0; while (iter < opt->opt.optlen) if (opt->opt.__data[iter] != IPOPT_NOP) { iter += opt->opt.__data[iter + 1]; optlen_new = iter; } else iter++; hdr_delta = opt->opt.optlen; opt->opt.optlen = (optlen_new + 3) & ~3; hdr_delta -= opt->opt.optlen; } else { /* only the cipso option was present on the socket so we can * remove the entire option struct */ *opt_ptr = NULL; hdr_delta = opt->opt.optlen; kfree_rcu(opt, rcu); } return hdr_delta; } /** * cipso_v4_sock_delattr - Delete the CIPSO option from a socket * @sk: the socket * * Description: * Removes the CIPSO option from a socket, if present. * */ void cipso_v4_sock_delattr(struct sock *sk) { int hdr_delta; struct ip_options_rcu *opt; struct inet_sock *sk_inet; sk_inet = inet_sk(sk); opt = rcu_dereference_protected(sk_inet->inet_opt, 1); if (!opt || opt->opt.cipso == 0) return; hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt); if (sk_inet->is_icsk && hdr_delta > 0) { struct inet_connection_sock *sk_conn = inet_csk(sk); sk_conn->icsk_ext_hdr_len -= hdr_delta; sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie); } } /** * cipso_v4_req_delattr - Delete the CIPSO option from a request socket * @reg: the request socket * * Description: * Removes the CIPSO option from a request socket, if present. * */ void cipso_v4_req_delattr(struct request_sock *req) { struct ip_options_rcu *opt; struct inet_request_sock *req_inet; req_inet = inet_rsk(req); opt = req_inet->opt; if (!opt || opt->opt.cipso == 0) return; cipso_v4_delopt(&req_inet->opt); } /** * cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions * @cipso: the CIPSO v4 option * @secattr: the security attributes * * Description: * Inspect @cipso and return the security attributes in @secattr. Returns zero * on success and negative values on failure. * */ int cipso_v4_getattr(const unsigned char *cipso, struct netlbl_lsm_secattr *secattr) { int ret_val = -ENOMSG; u32 doi; struct cipso_v4_doi *doi_def; if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0) return 0; doi = get_unaligned_be32(&cipso[2]); rcu_read_lock(); doi_def = cipso_v4_doi_search(doi); if (!doi_def) goto getattr_return; /* 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. */ switch (cipso[6]) { case CIPSO_V4_TAG_RBITMAP: ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr); break; case CIPSO_V4_TAG_ENUM: ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr); break; case CIPSO_V4_TAG_RANGE: ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr); break; case CIPSO_V4_TAG_LOCAL: ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr); break; } if (ret_val == 0) secattr->type = NETLBL_NLTYPE_CIPSOV4; getattr_return: rcu_read_unlock(); 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) { struct ip_options_rcu *opt; int res = -ENOMSG; rcu_read_lock(); opt = rcu_dereference(inet_sk(sk)->inet_opt); if (opt && opt->opt.cipso) res = cipso_v4_getattr(opt->opt.__data + opt->opt.cipso - sizeof(struct iphdr), secattr); rcu_read_unlock(); return res; } /** * cipso_v4_skbuff_setattr - Set the CIPSO option on a packet * @skb: the packet * @secattr: the security attributes * * Description: * Set the CIPSO option on the given packet based on the security attributes. * Returns a pointer to the IP header on success and NULL on failure. * */ int cipso_v4_skbuff_setattr(struct sk_buff *skb, const struct cipso_v4_doi *doi_def, const struct netlbl_lsm_secattr *secattr) { int ret_val; struct iphdr *iph; struct ip_options *opt = &IPCB(skb)->opt; unsigned char buf[CIPSO_V4_OPT_LEN_MAX]; u32 buf_len = CIPSO_V4_OPT_LEN_MAX; u32 opt_len; int len_delta; ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr); if (ret_val < 0) return ret_val; buf_len = ret_val; opt_len = (buf_len + 3) & ~3; /* we overwrite any existing options to ensure that we have enough * room for the CIPSO option, the reason is that we _need_ to guarantee * that the security label is applied to the packet - we do the same * thing when using the socket options and it hasn't caused a problem, * if we need to we can always revisit this choice later */ len_delta = opt_len - opt->optlen; /* if we don't ensure enough headroom we could panic on the skb_push() * call below so make sure we have enough, we are also "mangling" the * packet so we should probably do a copy-on-write call anyway */ ret_val = skb_cow(skb, skb_headroom(skb) + len_delta); if (ret_val < 0) return ret_val; if (len_delta > 0) { /* we assume that the header + opt->optlen have already been * "pushed" in ip_options_build() or similar */ iph = ip_hdr(skb); skb_push(skb, len_delta); memmove((char *)iph - len_delta, iph, iph->ihl << 2); skb_reset_network_header(skb); iph = ip_hdr(skb); } else if (len_delta < 0) { iph = ip_hdr(skb); memset(iph + 1, IPOPT_NOP, opt->optlen); } else iph = ip_hdr(skb); if (opt->optlen > 0) memset(opt, 0, sizeof(*opt)); opt->optlen = opt_len; opt->cipso = sizeof(struct iphdr); opt->is_changed = 1; /* we have to do the following because we are being called from a * netfilter hook which means the packet already has had the header * fields populated and the checksum calculated - yes this means we * are doing more work than needed but we do it to keep the core * stack clean and tidy */ memcpy(iph + 1, buf, buf_len); if (opt_len > buf_len) memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len); if (len_delta != 0) { iph->ihl = 5 + (opt_len >> 2); iph->tot_len = htons(skb->len); } ip_send_check(iph); return 0; } /** * cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet * @skb: the packet * * Description: * Removes any and all CIPSO options from the given packet. Returns zero on * success, negative values on failure. * */ int cipso_v4_skbuff_delattr(struct sk_buff *skb) { int ret_val; struct iphdr *iph; struct ip_options *opt = &IPCB(skb)->opt; unsigned char *cipso_ptr; if (opt->cipso == 0) return 0; /* since we are changing the packet we should make a copy */ ret_val = skb_cow(skb, skb_headroom(skb)); if (ret_val < 0) return ret_val; /* the easiest thing to do is just replace the cipso option with noop * options since we don't change the size of the packet, although we * still need to recalculate the checksum */ iph = ip_hdr(skb); cipso_ptr = (unsigned char *)iph + opt->cipso; memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]); opt->cipso = 0; opt->is_changed = 1; ip_send_check(iph); return 0; } /* * 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);