diff options
Diffstat (limited to 'net/ipv4/cipso_ipv4.c')
| -rw-r--r-- | net/ipv4/cipso_ipv4.c | 2296 |
1 files changed, 2296 insertions, 0 deletions
diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c new file mode 100644 index 000000000..d4a416015 --- /dev/null +++ b/net/ipv4/cipso_ipv4.c @@ -0,0 +1,2296 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * 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: + * https://tools.ietf.org/id/draft-ietf-cipso-ipsecurity-01.txt + * The FIPS-188 specification can be found at the following URL: + * https://www.itl.nist.gov/fipspubs/fip188.htm + * + * Author: Paul Moore <paul.moore@hp.com> + */ + +/* + * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 + */ + +#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 (!READ_ONCE(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; + refcount_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 + * @cipso_ptr: pointer to CIPSO IP option + * @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 bkt_size = READ_ONCE(cipso_v4_cache_bucketsize); + 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 (!READ_ONCE(cipso_v4_cache_enabled) || bkt_size <= 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); + refcount_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 < bkt_size) { + 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 && refcount_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; + } + } + + refcount_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); + kfree(doi_def->map.std); + 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_info: NetLabel audit information + * + * 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; + } + list_del_rcu(&doi_def->list); + spin_unlock(&cipso_v4_doi_list_lock); + + cipso_v4_doi_putdef(doi_def); + 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 (!refcount_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 (!refcount_dec_and_test(&doi_def->refcount)) + return; + + 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 (refcount_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 ((level < doi_def->map.std->lvl.cipso_size) && + (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 (READ_ONCE(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; + } + + if (secattr->attr.mls.cat) + 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; + } + + if (secattr->attr.mls.cat) + 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 is 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 > 1; ) { + switch (optptr[0]) { + case IPOPT_END: + return NULL; + case IPOPT_NOOP: + taglen = 1; + break; + default: + taglen = optptr[1]; + } + if (!taglen || taglen > optlen) + return NULL; + if (optptr[0] == IPOPT_CIPSO) + return optptr; + + optlen -= taglen; + optptr += taglen; + } + + return NULL; +} + +/** + * cipso_v4_validate - Validate a CIPSO option + * @skb: the packet + * @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; + } + + if (opt_iter + 1 == opt_len) { + 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 (READ_ONCE(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) +{ + unsigned char optbuf[sizeof(struct ip_options) + 40]; + struct ip_options *opt = (struct ip_options *)optbuf; + int res; + + if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES) + return; + + /* + * We might be called above the IP layer, + * so we can not use icmp_send and IPCB here. + */ + + memset(opt, 0, sizeof(struct ip_options)); + opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr); + rcu_read_lock(); + res = __ip_options_compile(dev_net(skb->dev), opt, skb, NULL); + rcu_read_unlock(); + + if (res) + return; + + if (gateway) + __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, opt); + else + __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, opt); +} + +/** + * 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((__force struct ip_options_rcu **)&req_inet->ireq_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 __rcu **opt_ptr) +{ + struct ip_options_rcu *opt = rcu_dereference_protected(*opt_ptr, 1); + int hdr_delta = 0; + + if (!opt || opt->opt.cipso == 0) + return 0; + 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) +{ + struct inet_sock *sk_inet; + int hdr_delta; + + sk_inet = inet_sk(sk); + + 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 + * @req: the request socket + * + * Description: + * Removes the CIPSO option from a request socket, if present. + * + */ +void cipso_v4_req_delattr(struct request_sock *req) +{ + cipso_v4_delopt(&inet_rsk(req)->ireq_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 + * @doi_def: the DOI structure + * @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); |