--- /dev/null
+/*
+ * CIPSO - Commercial IP Security Option
+ *
+ * This is an implementation of the CIPSO 2.2 protocol as specified in
+ * draft-ietf-cipso-ipsecurity-01.txt with additional tag types as found in
+ * FIPS-188, copies of both documents can be found in the Documentation
+ * directory. While CIPSO never became a full IETF RFC standard many vendors
+ * have chosen to adopt the protocol and over the years it has become a
+ * de-facto standard for labeled networking.
+ *
+ * Author: Paul Moore <paul.moore@hp.com>
+ *
+ */
+
+/*
+ * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/rcupdate.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/jhash.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/tcp.h>
+#include <net/netlabel.h>
+#include <net/cipso_ipv4.h>
+#include <asm/atomic.h>
+#include <asm/bug.h>
+
+struct cipso_v4_domhsh_entry {
+ char *domain;
+ u32 valid;
+ struct list_head list;
+ struct rcu_head rcu;
+};
+
+/* List of available DOI definitions */
+/* XXX - Updates should be minimal so having a single lock for the
+ * cipso_v4_doi_list and the cipso_v4_doi_list->dom_list should be
+ * okay. */
+/* XXX - This currently assumes a minimal number of different DOIs in use,
+ * if in practice there are a lot of different DOIs this list should
+ * probably be turned into a hash table or something similar so we
+ * can do quick lookups. */
+static DEFINE_SPINLOCK(cipso_v4_doi_list_lock);
+static struct list_head cipso_v4_doi_list = LIST_HEAD_INIT(cipso_v4_doi_list);
+
+/* Label mapping cache */
+int cipso_v4_cache_enabled = 1;
+int cipso_v4_cache_bucketsize = 10;
+#define CIPSO_V4_CACHE_BUCKETBITS 7
+#define CIPSO_V4_CACHE_BUCKETS (1 << CIPSO_V4_CACHE_BUCKETBITS)
+#define CIPSO_V4_CACHE_REORDERLIMIT 10
+struct cipso_v4_map_cache_bkt {
+ spinlock_t lock;
+ u32 size;
+ struct list_head list;
+};
+struct cipso_v4_map_cache_entry {
+ u32 hash;
+ unsigned char *key;
+ size_t key_len;
+
+ struct netlbl_lsm_cache *lsm_data;
+
+ u32 activity;
+ struct list_head list;
+};
+static struct cipso_v4_map_cache_bkt *cipso_v4_cache = NULL;
+
+/* Restricted bitmap (tag #1) flags */
+int cipso_v4_rbm_optfmt = 0;
+int cipso_v4_rbm_strictvalid = 1;
+
+/*
+ * Helper Functions
+ */
+
+/**
+ * cipso_v4_bitmap_walk - Walk a bitmap looking for a bit
+ * @bitmap: the bitmap
+ * @bitmap_len: length in bits
+ * @offset: starting offset
+ * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit
+ *
+ * Description:
+ * Starting at @offset, walk the bitmap from left to right until either the
+ * desired bit is found or we reach the end. Return the bit offset, -1 if
+ * not found, or -2 if error.
+ */
+static int cipso_v4_bitmap_walk(const unsigned char *bitmap,
+ u32 bitmap_len,
+ u32 offset,
+ u8 state)
+{
+ u32 bit_spot;
+ u32 byte_offset;
+ unsigned char bitmask;
+ unsigned char byte;
+
+ /* gcc always rounds to zero when doing integer division */
+ byte_offset = offset / 8;
+ byte = bitmap[byte_offset];
+ bit_spot = offset;
+ bitmask = 0x80 >> (offset % 8);
+
+ while (bit_spot < bitmap_len) {
+ if ((state && (byte & bitmask) == bitmask) ||
+ (state == 0 && (byte & bitmask) == 0))
+ return bit_spot;
+
+ bit_spot++;
+ bitmask >>= 1;
+ if (bitmask == 0) {
+ byte = bitmap[++byte_offset];
+ bitmask = 0x80;
+ }
+ }
+
+ return -1;
+}
+
+/**
+ * cipso_v4_bitmap_setbit - Sets a single bit in a bitmap
+ * @bitmap: the bitmap
+ * @bit: the bit
+ * @state: if non-zero, set the bit (1) else clear the bit (0)
+ *
+ * Description:
+ * Set a single bit in the bitmask. Returns zero on success, negative values
+ * on error.
+ */
+static void cipso_v4_bitmap_setbit(unsigned char *bitmap,
+ u32 bit,
+ u8 state)
+{
+ u32 byte_spot;
+ u8 bitmask;
+
+ /* gcc always rounds to zero when doing integer division */
+ byte_spot = bit / 8;
+ bitmask = 0x80 >> (bit % 8);
+ if (state)
+ bitmap[byte_spot] |= bitmask;
+ else
+ bitmap[byte_spot] &= ~bitmask;
+}
+
+/**
+ * cipso_v4_doi_domhsh_free - Frees a domain list entry
+ * @entry: the entry's RCU field
+ *
+ * Description:
+ * This function is designed to be used as a callback to the call_rcu()
+ * function so that the memory allocated to a domain list entry can be released
+ * safely.
+ *
+ */
+static void cipso_v4_doi_domhsh_free(struct rcu_head *entry)
+{
+ struct cipso_v4_domhsh_entry *ptr;
+
+ ptr = container_of(entry, struct cipso_v4_domhsh_entry, rcu);
+ kfree(ptr->domain);
+ kfree(ptr);
+}
+
+/**
+ * cipso_v4_cache_entry_free - Frees a cache entry
+ * @entry: the entry to free
+ *
+ * Description:
+ * This function frees the memory associated with a cache entry including the
+ * LSM cache data if there are no longer any users, i.e. reference count == 0.
+ *
+ */
+static void cipso_v4_cache_entry_free(struct cipso_v4_map_cache_entry *entry)
+{
+ if (entry->lsm_data)
+ netlbl_secattr_cache_free(entry->lsm_data);
+ kfree(entry->key);
+ kfree(entry);
+}
+
+/**
+ * cipso_v4_map_cache_hash - Hashing function for the CIPSO cache
+ * @key: the hash key
+ * @key_len: the length of the key in bytes
+ *
+ * Description:
+ * The CIPSO tag hashing function. Returns a 32-bit hash value.
+ *
+ */
+static u32 cipso_v4_map_cache_hash(const unsigned char *key, u32 key_len)
+{
+ return jhash(key, key_len, 0);
+}
+
+/*
+ * Label Mapping Cache Functions
+ */
+
+/**
+ * cipso_v4_cache_init - Initialize the CIPSO cache
+ *
+ * Description:
+ * Initializes the CIPSO label mapping cache, this function should be called
+ * before any of the other functions defined in this file. Returns zero on
+ * success, negative values on error.
+ *
+ */
+static int cipso_v4_cache_init(void)
+{
+ u32 iter;
+
+ cipso_v4_cache = kcalloc(CIPSO_V4_CACHE_BUCKETS,
+ sizeof(struct cipso_v4_map_cache_bkt),
+ GFP_KERNEL);
+ if (cipso_v4_cache == NULL)
+ return -ENOMEM;
+
+ for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
+ spin_lock_init(&cipso_v4_cache[iter].lock);
+ cipso_v4_cache[iter].size = 0;
+ INIT_LIST_HEAD(&cipso_v4_cache[iter].list);
+ }
+
+ return 0;
+}
+
+/**
+ * cipso_v4_cache_invalidate - Invalidates the current CIPSO cache
+ *
+ * Description:
+ * Invalidates and frees any entries in the CIPSO cache. Returns zero on
+ * success and negative values on failure.
+ *
+ */
+void cipso_v4_cache_invalidate(void)
+{
+ struct cipso_v4_map_cache_entry *entry, *tmp_entry;
+ u32 iter;
+
+ for (iter = 0; iter < CIPSO_V4_CACHE_BUCKETS; iter++) {
+ spin_lock_bh(&cipso_v4_cache[iter].lock);
+ list_for_each_entry_safe(entry,
+ tmp_entry,
+ &cipso_v4_cache[iter].list, list) {
+ list_del(&entry->list);
+ cipso_v4_cache_entry_free(entry);
+ }
+ cipso_v4_cache[iter].size = 0;
+ spin_unlock_bh(&cipso_v4_cache[iter].lock);
+ }
+
+ return;
+}
+
+/**
+ * cipso_v4_cache_check - Check the CIPSO cache for a label mapping
+ * @key: the buffer to check
+ * @key_len: buffer length in bytes
+ * @secattr: the security attribute struct to use
+ *
+ * Description:
+ * This function checks the cache to see if a label mapping already exists for
+ * the given key. If there is a match then the cache is adjusted and the
+ * @secattr struct is populated with the correct LSM security attributes. The
+ * cache is adjusted in the following manner if the entry is not already the
+ * first in the cache bucket:
+ *
+ * 1. The cache entry's activity counter is incremented
+ * 2. The previous (higher ranking) entry's activity counter is decremented
+ * 3. If the difference between the two activity counters is geater than
+ * CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped
+ *
+ * Returns zero on success, -ENOENT for a cache miss, and other negative values
+ * on error.
+ *
+ */
+static int cipso_v4_cache_check(const unsigned char *key,
+ u32 key_len,
+ struct netlbl_lsm_secattr *secattr)
+{
+ u32 bkt;
+ struct cipso_v4_map_cache_entry *entry;
+ struct cipso_v4_map_cache_entry *prev_entry = NULL;
+ u32 hash;
+
+ if (!cipso_v4_cache_enabled)
+ return -ENOENT;
+
+ hash = cipso_v4_map_cache_hash(key, key_len);
+ bkt = hash & (CIPSO_V4_CACHE_BUCKETBITS - 1);
+ spin_lock_bh(&cipso_v4_cache[bkt].lock);
+ list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
+ if (entry->hash == hash &&
+ entry->key_len == key_len &&
+ memcmp(entry->key, key, key_len) == 0) {
+ entry->activity += 1;
+ atomic_inc(&entry->lsm_data->refcount);
+ secattr->cache = entry->lsm_data;
+ secattr->flags |= NETLBL_SECATTR_CACHE;
+ if (prev_entry == NULL) {
+ spin_unlock_bh(&cipso_v4_cache[bkt].lock);
+ return 0;
+ }
+
+ if (prev_entry->activity > 0)
+ prev_entry->activity -= 1;
+ if (entry->activity > prev_entry->activity &&
+ entry->activity - prev_entry->activity >
+ CIPSO_V4_CACHE_REORDERLIMIT) {
+ __list_del(entry->list.prev, entry->list.next);
+ __list_add(&entry->list,
+ prev_entry->list.prev,
+ &prev_entry->list);
+ }
+
+ spin_unlock_bh(&cipso_v4_cache[bkt].lock);
+ return 0;
+ }
+ prev_entry = entry;
+ }
+ spin_unlock_bh(&cipso_v4_cache[bkt].lock);
+
+ return -ENOENT;
+}
+
+/**
+ * cipso_v4_cache_add - Add an entry to the CIPSO cache
+ * @skb: the packet
+ * @secattr: the packet's security attributes
+ *
+ * Description:
+ * Add a new entry into the CIPSO label mapping cache. Add the new entry to
+ * head of the cache bucket's list, if the cache bucket is out of room remove
+ * the last entry in the list first. It is important to note that there is
+ * currently no checking for duplicate keys. Returns zero on success,
+ * negative values on failure.
+ *
+ */
+int cipso_v4_cache_add(const struct sk_buff *skb,
+ const struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val = -EPERM;
+ u32 bkt;
+ struct cipso_v4_map_cache_entry *entry = NULL;
+ struct cipso_v4_map_cache_entry *old_entry = NULL;
+ unsigned char *cipso_ptr;
+ u32 cipso_ptr_len;
+
+ if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0)
+ return 0;
+
+ cipso_ptr = CIPSO_V4_OPTPTR(skb);
+ cipso_ptr_len = cipso_ptr[1];
+
+ entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
+ if (entry == NULL)
+ return -ENOMEM;
+ entry->key = kmemdup(cipso_ptr, cipso_ptr_len, GFP_ATOMIC);
+ if (entry->key == NULL) {
+ 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_BUCKETBITS - 1);
+ spin_lock_bh(&cipso_v4_cache[bkt].lock);
+ if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) {
+ list_add(&entry->list, &cipso_v4_cache[bkt].list);
+ cipso_v4_cache[bkt].size += 1;
+ } else {
+ old_entry = list_entry(cipso_v4_cache[bkt].list.prev,
+ struct cipso_v4_map_cache_entry, list);
+ list_del(&old_entry->list);
+ list_add(&entry->list, &cipso_v4_cache[bkt].list);
+ cipso_v4_cache_entry_free(old_entry);
+ }
+ spin_unlock_bh(&cipso_v4_cache[bkt].lock);
+
+ return 0;
+
+cache_add_failure:
+ if (entry)
+ cipso_v4_cache_entry_free(entry);
+ return ret_val;
+}
+
+/*
+ * DOI List Functions
+ */
+
+/**
+ * cipso_v4_doi_search - Searches for a DOI definition
+ * @doi: the DOI to search for
+ *
+ * Description:
+ * Search the DOI definition list for a DOI definition with a DOI value that
+ * matches @doi. The caller is responsibile for calling rcu_read_[un]lock().
+ * Returns a pointer to the DOI definition on success and NULL on failure.
+ */
+static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi)
+{
+ struct cipso_v4_doi *iter;
+
+ list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list)
+ if (iter->doi == doi && iter->valid)
+ return iter;
+ return NULL;
+}
+
+/**
+ * cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine
+ * @doi_def: the DOI structure
+ *
+ * Description:
+ * The caller defines a new DOI for use by the CIPSO engine and calls this
+ * function to add it to the list of acceptable domains. The caller must
+ * ensure that the mapping table specified in @doi_def->map meets all of the
+ * requirements of the mapping type (see cipso_ipv4.h for details). Returns
+ * zero on success and non-zero on failure.
+ *
+ */
+int cipso_v4_doi_add(struct cipso_v4_doi *doi_def)
+{
+ u32 iter;
+
+ if (doi_def == NULL || doi_def->doi == CIPSO_V4_DOI_UNKNOWN)
+ return -EINVAL;
+ 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:
+ if (doi_def->type != CIPSO_V4_MAP_PASS)
+ return -EINVAL;
+ break;
+ case CIPSO_V4_TAG_INVALID:
+ if (iter == 0)
+ return -EINVAL;
+ break;
+ case CIPSO_V4_TAG_ENUM:
+ if (doi_def->type != CIPSO_V4_MAP_PASS)
+ return -EINVAL;
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ doi_def->valid = 1;
+ INIT_RCU_HEAD(&doi_def->rcu);
+ INIT_LIST_HEAD(&doi_def->dom_list);
+
+ rcu_read_lock();
+ if (cipso_v4_doi_search(doi_def->doi) != NULL)
+ goto doi_add_failure_rlock;
+ spin_lock(&cipso_v4_doi_list_lock);
+ if (cipso_v4_doi_search(doi_def->doi) != NULL)
+ goto doi_add_failure_slock;
+ list_add_tail_rcu(&doi_def->list, &cipso_v4_doi_list);
+ spin_unlock(&cipso_v4_doi_list_lock);
+ rcu_read_unlock();
+
+ return 0;
+
+doi_add_failure_slock:
+ spin_unlock(&cipso_v4_doi_list_lock);
+doi_add_failure_rlock:
+ rcu_read_unlock();
+ return -EEXIST;
+}
+
+/**
+ * cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine
+ * @doi: the DOI value
+ * @audit_secid: the LSM secid to use in the audit message
+ * @callback: the DOI cleanup/free callback
+ *
+ * Description:
+ * Removes a DOI definition from the CIPSO engine, @callback is called to
+ * free any memory. The NetLabel routines will be called to release their own
+ * LSM domain mappings as well as our own domain list. Returns zero on
+ * success and negative values on failure.
+ *
+ */
+int cipso_v4_doi_remove(u32 doi,
+ struct netlbl_audit *audit_info,
+ void (*callback) (struct rcu_head * head))
+{
+ struct cipso_v4_doi *doi_def;
+ struct cipso_v4_domhsh_entry *dom_iter;
+
+ rcu_read_lock();
+ if (cipso_v4_doi_search(doi) != NULL) {
+ spin_lock(&cipso_v4_doi_list_lock);
+ doi_def = cipso_v4_doi_search(doi);
+ if (doi_def == NULL) {
+ spin_unlock(&cipso_v4_doi_list_lock);
+ rcu_read_unlock();
+ return -ENOENT;
+ }
+ doi_def->valid = 0;
+ list_del_rcu(&doi_def->list);
+ spin_unlock(&cipso_v4_doi_list_lock);
+ list_for_each_entry_rcu(dom_iter, &doi_def->dom_list, list)
+ if (dom_iter->valid)
+ netlbl_domhsh_remove(dom_iter->domain,
+ audit_info);
+ cipso_v4_cache_invalidate();
+ rcu_read_unlock();
+
+ call_rcu(&doi_def->rcu, callback);
+ return 0;
+ }
+ rcu_read_unlock();
+
+ return -ENOENT;
+}
+
+/**
+ * cipso_v4_doi_getdef - Returns a pointer to a valid DOI definition
+ * @doi: the DOI value
+ *
+ * Description:
+ * Searches for a valid DOI definition and if one is found it is returned to
+ * the caller. Otherwise NULL is returned. The caller must ensure that
+ * rcu_read_lock() is held while accessing the returned definition.
+ *
+ */
+struct cipso_v4_doi *cipso_v4_doi_getdef(u32 doi)
+{
+ return cipso_v4_doi_search(doi);
+}
+
+/**
+ * cipso_v4_doi_walk - Iterate through the DOI definitions
+ * @skip_cnt: skip past this number of DOI definitions, updated
+ * @callback: callback for each DOI definition
+ * @cb_arg: argument for the callback function
+ *
+ * Description:
+ * Iterate over the DOI definition list, skipping the first @skip_cnt entries.
+ * For each entry call @callback, if @callback returns a negative value stop
+ * 'walking' through the list and return. Updates the value in @skip_cnt upon
+ * return. Returns zero on success, negative values on failure.
+ *
+ */
+int cipso_v4_doi_walk(u32 *skip_cnt,
+ int (*callback) (struct cipso_v4_doi *doi_def, void *arg),
+ void *cb_arg)
+{
+ int ret_val = -ENOENT;
+ u32 doi_cnt = 0;
+ struct cipso_v4_doi *iter_doi;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
+ if (iter_doi->valid) {
+ if (doi_cnt++ < *skip_cnt)
+ continue;
+ ret_val = callback(iter_doi, cb_arg);
+ if (ret_val < 0) {
+ doi_cnt--;
+ goto doi_walk_return;
+ }
+ }
+
+doi_walk_return:
+ rcu_read_unlock();
+ *skip_cnt = doi_cnt;
+ return ret_val;
+}
+
+/**
+ * cipso_v4_doi_domhsh_add - Adds a domain entry to a DOI definition
+ * @doi_def: the DOI definition
+ * @domain: the domain to add
+ *
+ * Description:
+ * Adds the @domain to the the DOI specified by @doi_def, this function
+ * should only be called by external functions (i.e. NetLabel). This function
+ * does allocate memory. Returns zero on success, negative values on failure.
+ *
+ */
+int cipso_v4_doi_domhsh_add(struct cipso_v4_doi *doi_def, const char *domain)
+{
+ struct cipso_v4_domhsh_entry *iter;
+ struct cipso_v4_domhsh_entry *new_dom;
+
+ new_dom = kzalloc(sizeof(*new_dom), GFP_KERNEL);
+ if (new_dom == NULL)
+ return -ENOMEM;
+ if (domain) {
+ new_dom->domain = kstrdup(domain, GFP_KERNEL);
+ if (new_dom->domain == NULL) {
+ kfree(new_dom);
+ return -ENOMEM;
+ }
+ }
+ new_dom->valid = 1;
+ INIT_RCU_HEAD(&new_dom->rcu);
+
+ rcu_read_lock();
+ spin_lock(&cipso_v4_doi_list_lock);
+ list_for_each_entry_rcu(iter, &doi_def->dom_list, list)
+ if (iter->valid &&
+ ((domain != NULL && iter->domain != NULL &&
+ strcmp(iter->domain, domain) == 0) ||
+ (domain == NULL && iter->domain == NULL))) {
+ spin_unlock(&cipso_v4_doi_list_lock);
+ rcu_read_unlock();
+ kfree(new_dom->domain);
+ kfree(new_dom);
+ return -EEXIST;
+ }
+ list_add_tail_rcu(&new_dom->list, &doi_def->dom_list);
+ spin_unlock(&cipso_v4_doi_list_lock);
+ rcu_read_unlock();
+
+ return 0;
+}
+
+/**
+ * cipso_v4_doi_domhsh_remove - Removes a domain entry from a DOI definition
+ * @doi_def: the DOI definition
+ * @domain: the domain to remove
+ *
+ * Description:
+ * Removes the @domain from the DOI specified by @doi_def, this function
+ * should only be called by external functions (i.e. NetLabel). Returns zero
+ * on success and negative values on error.
+ *
+ */
+int cipso_v4_doi_domhsh_remove(struct cipso_v4_doi *doi_def,
+ const char *domain)
+{
+ struct cipso_v4_domhsh_entry *iter;
+
+ rcu_read_lock();
+ spin_lock(&cipso_v4_doi_list_lock);
+ list_for_each_entry_rcu(iter, &doi_def->dom_list, list)
+ if (iter->valid &&
+ ((domain != NULL && iter->domain != NULL &&
+ strcmp(iter->domain, domain) == 0) ||
+ (domain == NULL && iter->domain == NULL))) {
+ iter->valid = 0;
+ list_del_rcu(&iter->list);
+ spin_unlock(&cipso_v4_doi_list_lock);
+ rcu_read_unlock();
+ call_rcu(&iter->rcu, cipso_v4_doi_domhsh_free);
+
+ return 0;
+ }
+ spin_unlock(&cipso_v4_doi_list_lock);
+ rcu_read_unlock();
+
+ return -ENOENT;
+}
+
+/*
+ * Label Mapping Functions
+ */
+
+/**
+ * cipso_v4_map_lvl_valid - Checks to see if the given level is understood
+ * @doi_def: the DOI definition
+ * @level: the level to check
+ *
+ * Description:
+ * Checks the given level against the given DOI definition and returns a
+ * negative value if the level does not have a valid mapping and a zero value
+ * if the level is defined by the DOI.
+ *
+ */
+static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
+{
+ switch (doi_def->type) {
+ case CIPSO_V4_MAP_PASS:
+ return 0;
+ case CIPSO_V4_MAP_STD:
+ if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL)
+ return 0;
+ break;
+ }
+
+ return -EFAULT;
+}
+
+/**
+ * cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
+ * @doi_def: the DOI definition
+ * @host_lvl: the host MLS level
+ * @net_lvl: the network/CIPSO MLS level
+ *
+ * Description:
+ * Perform a label mapping to translate a local MLS level to the correct
+ * CIPSO level using the given DOI definition. Returns zero on success,
+ * negative values otherwise.
+ *
+ */
+static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
+ u32 host_lvl,
+ u32 *net_lvl)
+{
+ switch (doi_def->type) {
+ case CIPSO_V4_MAP_PASS:
+ *net_lvl = host_lvl;
+ return 0;
+ case CIPSO_V4_MAP_STD:
+ if (host_lvl < doi_def->map.std->lvl.local_size &&
+ 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_STD:
+ map_tbl = doi_def->map.std;
+ if (net_lvl < map_tbl->lvl.cipso_size &&
+ map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
+ *host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
+ return 0;
+ }
+ 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_STD:
+ cipso_cat_size = doi_def->map.std->cat.cipso_size;
+ cipso_array = doi_def->map.std->cat.cipso;
+ for (;;) {
+ cat = cipso_v4_bitmap_walk(bitmap,
+ bitmap_len_bits,
+ cat + 1,
+ 1);
+ if (cat < 0)
+ break;
+ if (cat >= cipso_cat_size ||
+ cipso_array[cat] >= CIPSO_V4_INV_CAT)
+ return -EFAULT;
+ }
+
+ if (cat == -1)
+ return 0;
+ break;
+ }
+
+ return -EFAULT;
+}
+
+/**
+ * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
+ * @doi_def: the DOI definition
+ * @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_STD) {
+ host_cat_size = doi_def->map.std->cat.local_size;
+ host_cat_array = doi_def->map.std->cat.local;
+ }
+
+ for (;;) {
+ host_spot = netlbl_secattr_catmap_walk(secattr->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_STD:
+ 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;
+ cipso_v4_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_STD) {
+ net_cat_size = doi_def->map.std->cat.cipso_size;
+ net_cat_array = doi_def->map.std->cat.cipso;
+ }
+
+ for (;;) {
+ net_spot = cipso_v4_bitmap_walk(net_cat,
+ net_clen_bits,
+ net_spot + 1,
+ 1);
+ if (net_spot < 0) {
+ 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_STD:
+ 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_secattr_catmap_setbit(secattr->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 = ntohs(*((__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_secattr_catmap_walk(secattr->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_secattr_catmap_setbit(secattr->mls_cat,
+ ntohs(*((__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 = ntohs(*((__be16 *)&rngcat[iter]));
+ if ((iter + 4) <= rngcat_len)
+ cat_low = ntohs(*((__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)
+{
+ /* The constant '16' is not random, it is the maximum number of
+ * high/low category range pairs as permitted by the CIPSO draft based
+ * on a maximum IPv4 header length of 60 bytes - the BUG_ON() assertion
+ * does a sanity check to make sure we don't overflow the array. */
+ int iter = -1;
+ u16 array[16];
+ u32 array_cnt = 0;
+ u32 cat_size = 0;
+
+ BUG_ON(net_cat_len > 30);
+
+ for (;;) {
+ iter = netlbl_secattr_catmap_walk(secattr->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_secattr_catmap_walk_rng(secattr->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 = ntohs(*((__be16 *)&net_cat[net_iter]));
+ if ((net_iter + 4) <= net_cat_len)
+ cat_low = ntohs(*((__be16 *)&net_cat[net_iter + 2]));
+ else
+ cat_low = 0;
+
+ ret_val = netlbl_secattr_catmap_setrng(secattr->mls_cat,
+ cat_low,
+ cat_high,
+ GFP_ATOMIC);
+ if (ret_val != 0)
+ return ret_val;
+ }
+
+ return 0;
+}
+
+/*
+ * Protocol Handling Functions
+ */
+
+#define CIPSO_V4_OPT_LEN_MAX 40
+#define CIPSO_V4_HDR_LEN 6
+
+/**
+ * cipso_v4_gentag_hdr - Generate a CIPSO option header
+ * @doi_def: the DOI definition
+ * @len: the total tag length in bytes, 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->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
+ * possibile 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] = 0x01;
+ 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->mls_lvl = level;
+ secattr->flags |= NETLBL_SECATTR_MLS_LVL;
+
+ if (tag_len > 4) {
+ secattr->mls_cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
+ if (secattr->mls_cat == NULL)
+ return -ENOMEM;
+
+ ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
+ &tag[4],
+ tag_len - 4,
+ secattr);
+ if (ret_val != 0) {
+ netlbl_secattr_catmap_free(secattr->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->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] = 0x02;
+ 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->mls_lvl = level;
+ secattr->flags |= NETLBL_SECATTR_MLS_LVL;
+
+ if (tag_len > 4) {
+ secattr->mls_cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
+ if (secattr->mls_cat == NULL)
+ return -ENOMEM;
+
+ ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
+ &tag[4],
+ tag_len - 4,
+ secattr);
+ if (ret_val != 0) {
+ netlbl_secattr_catmap_free(secattr->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->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] = 0x05;
+ 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->mls_lvl = level;
+ secattr->flags |= NETLBL_SECATTR_MLS_LVL;
+
+ if (tag_len > 4) {
+ secattr->mls_cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
+ if (secattr->mls_cat == NULL)
+ return -ENOMEM;
+
+ ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
+ &tag[4],
+ tag_len - 4,
+ secattr);
+ if (ret_val != 0) {
+ netlbl_secattr_catmap_free(secattr->mls_cat);
+ return ret_val;
+ }
+
+ secattr->flags |= NETLBL_SECATTR_MLS_CAT;
+ }
+
+ return 0;
+}
+
+/**
+ * cipso_v4_validate - Validate a CIPSO option
+ * @option: the start of the option, on error it is set to point to the error
+ *
+ * Description:
+ * This routine is called to validate a CIPSO option, it checks all of the
+ * fields to ensure that they are at least valid, see the draft snippet below
+ * for details. If the option is valid then a zero value is returned and
+ * the value of @option is unchanged. If the option is invalid then a
+ * non-zero value is returned and @option is adjusted to point to the
+ * offending portion of the option. From the IETF draft ...
+ *
+ * "If any field within the CIPSO options, such as the DOI identifier, is not
+ * recognized the IP datagram is discarded and an ICMP 'parameter problem'
+ * (type 12) is generated and returned. The ICMP code field is set to 'bad
+ * parameter' (code 0) and the pointer is set to the start of the CIPSO field
+ * that is unrecognized."
+ *
+ */
+int cipso_v4_validate(unsigned char **option)
+{
+ unsigned char *opt = *option;
+ unsigned char *tag;
+ unsigned char opt_iter;
+ unsigned char err_offset = 0;
+ u8 opt_len;
+ u8 tag_len;
+ struct cipso_v4_doi *doi_def = NULL;
+ u32 tag_iter;
+
+ /* caller already checks for length values that are too large */
+ opt_len = opt[1];
+ if (opt_len < 8) {
+ err_offset = 1;
+ goto validate_return;
+ }
+
+ rcu_read_lock();
+ doi_def = cipso_v4_doi_search(ntohl(*((__be32 *)&opt[2])));
+ if (doi_def == NULL) {
+ err_offset = 2;
+ goto validate_return_locked;
+ }
+
+ opt_iter = 6;
+ tag = opt + opt_iter;
+ while (opt_iter < opt_len) {
+ for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
+ if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
+ ++tag_iter == CIPSO_V4_TAG_MAXCNT) {
+ err_offset = opt_iter;
+ goto validate_return_locked;
+ }
+
+ tag_len = tag[1];
+ if (tag_len > (opt_len - opt_iter)) {
+ err_offset = opt_iter + 1;
+ goto validate_return_locked;
+ }
+
+ switch (tag[0]) {
+ case CIPSO_V4_TAG_RBITMAP:
+ if (tag_len < 4) {
+ err_offset = opt_iter + 1;
+ goto validate_return_locked;
+ }
+
+ /* We are already going to do all the verification
+ * necessary at the socket layer so from our point of
+ * view it is safe to turn these checks off (and less
+ * work), however, the CIPSO draft says we should do
+ * all the CIPSO validations here but it doesn't
+ * really specify _exactly_ what we need to validate
+ * ... so, just make it a sysctl tunable. */
+ if (cipso_v4_rbm_strictvalid) {
+ if (cipso_v4_map_lvl_valid(doi_def,
+ tag[3]) < 0) {
+ err_offset = opt_iter + 3;
+ goto validate_return_locked;
+ }
+ if (tag_len > 4 &&
+ cipso_v4_map_cat_rbm_valid(doi_def,
+ &tag[4],
+ tag_len - 4) < 0) {
+ err_offset = opt_iter + 4;
+ goto validate_return_locked;
+ }
+ }
+ break;
+ case CIPSO_V4_TAG_ENUM:
+ if (tag_len < 4) {
+ 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 > 4 &&
+ 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 < 4) {
+ 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 > 4 &&
+ cipso_v4_map_cat_rng_valid(doi_def,
+ &tag[4],
+ tag_len - 4) < 0) {
+ err_offset = opt_iter + 4;
+ goto validate_return_locked;
+ }
+ break;
+ default:
+ err_offset = opt_iter;
+ goto validate_return_locked;
+ }
+
+ tag += tag_len;
+ opt_iter += tag_len;
+ }
+
+validate_return_locked:
+ rcu_read_unlock();
+validate_return:
+ *option = opt + err_offset;
+ return err_offset;
+}
+
+/**
+ * cipso_v4_error - Send the correct reponse for a bad packet
+ * @skb: the packet
+ * @error: the error code
+ * @gateway: CIPSO gateway flag
+ *
+ * Description:
+ * Based on the error code given in @error, send an ICMP error message back to
+ * the originating host. From the IETF draft ...
+ *
+ * "If the contents of the CIPSO [option] are valid but the security label is
+ * outside of the configured host or port label range, the datagram is
+ * discarded and an ICMP 'destination unreachable' (type 3) is generated and
+ * returned. The code field of the ICMP is set to 'communication with
+ * destination network administratively prohibited' (code 9) or to
+ * 'communication with destination host administratively prohibited'
+ * (code 10). The value of the code is dependent on whether the originator
+ * of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The
+ * recipient of the ICMP message MUST be able to handle either value. The
+ * same procedure is performed if a CIPSO [option] can not be added to an
+ * IP packet because it is too large to fit in the IP options area."
+ *
+ * "If the error is triggered by receipt of an ICMP message, the message is
+ * discarded and no response is permitted (consistent with general ICMP
+ * processing rules)."
+ *
+ */
+void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
+{
+ if (skb->nh.iph->protocol == IPPROTO_ICMP || error != -EACCES)
+ return;
+
+ if (gateway)
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
+ else
+ icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
+}
+
+/**
+ * cipso_v4_socket_setattr - Add a CIPSO option to a socket
+ * @sock: the socket
+ * @doi_def: the CIPSO DOI to use
+ * @secattr: the specific security attributes of the socket
+ *
+ * Description:
+ * Set the CIPSO option on the given socket using the DOI definition and
+ * security attributes passed to the function. This function requires
+ * exclusive access to @sock->sk, which means it either needs to be in the
+ * process of being created or locked via lock_sock(sock->sk). Returns zero on
+ * success and negative values on failure.
+ *
+ */
+int cipso_v4_socket_setattr(const struct socket *sock,
+ const struct cipso_v4_doi *doi_def,
+ const struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val = -EPERM;
+ u32 iter;
+ unsigned char *buf;
+ u32 buf_len = 0;
+ u32 opt_len;
+ struct ip_options *opt = NULL;
+ struct sock *sk;
+ struct inet_sock *sk_inet;
+ struct inet_connection_sock *sk_conn;
+
+ /* In the case of sock_create_lite(), the sock->sk field is not
+ * defined yet but it is not a problem as the only users of these
+ * "lite" PF_INET sockets are functions which do an accept() call
+ * afterwards so we will label the socket as part of the accept(). */
+ sk = sock->sk;
+ if (sk == NULL)
+ return 0;
+
+ /* 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 == NULL) {
+ ret_val = -ENOMEM;
+ goto socket_setattr_failure;
+ }
+
+ /* 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;
+ default:
+ ret_val = -EPERM;
+ goto socket_setattr_failure;
+ }
+
+ iter++;
+ } while (ret_val < 0 &&
+ iter < CIPSO_V4_TAG_MAXCNT &&
+ doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
+ if (ret_val < 0)
+ goto socket_setattr_failure;
+ cipso_v4_gentag_hdr(doi_def, buf, ret_val);
+ buf_len = CIPSO_V4_HDR_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 == NULL) {
+ ret_val = -ENOMEM;
+ goto socket_setattr_failure;
+ }
+ memcpy(opt->__data, buf, buf_len);
+ opt->optlen = opt_len;
+ opt->is_data = 1;
+ opt->cipso = sizeof(struct iphdr);
+ kfree(buf);
+ buf = NULL;
+
+ sk_inet = inet_sk(sk);
+ if (sk_inet->is_icsk) {
+ sk_conn = inet_csk(sk);
+ if (sk_inet->opt)
+ sk_conn->icsk_ext_hdr_len -= sk_inet->opt->optlen;
+ sk_conn->icsk_ext_hdr_len += opt->optlen;
+ sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
+ }
+ opt = xchg(&sk_inet->opt, opt);
+ kfree(opt);
+
+ return 0;
+
+socket_setattr_failure:
+ kfree(buf);
+ kfree(opt);
+ return ret_val;
+}
+
+/**
+ * cipso_v4_sock_getattr - Get the security attributes from a sock
+ * @sk: the sock
+ * @secattr: the security attributes
+ *
+ * Description:
+ * Query @sk to see if there is a CIPSO option attached to the sock and if
+ * there is return the CIPSO security attributes in @secattr. This function
+ * requires that @sk be locked, or privately held, but it does not do any
+ * locking itself. Returns zero on success and negative values on failure.
+ *
+ */
+int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val = -ENOMSG;
+ struct inet_sock *sk_inet;
+ unsigned char *cipso_ptr;
+ u32 doi;
+ struct cipso_v4_doi *doi_def;
+
+ sk_inet = inet_sk(sk);
+ if (sk_inet->opt == NULL || sk_inet->opt->cipso == 0)
+ return -ENOMSG;
+ cipso_ptr = sk_inet->opt->__data + sk_inet->opt->cipso -
+ sizeof(struct iphdr);
+ ret_val = cipso_v4_cache_check(cipso_ptr, cipso_ptr[1], secattr);
+ if (ret_val == 0)
+ return ret_val;
+
+ doi = ntohl(*(__be32 *)&cipso_ptr[2]);
+ rcu_read_lock();
+ doi_def = cipso_v4_doi_search(doi);
+ if (doi_def == NULL) {
+ rcu_read_unlock();
+ return -ENOMSG;
+ }
+
+ /* 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_ptr[6]) {
+ case CIPSO_V4_TAG_RBITMAP:
+ ret_val = cipso_v4_parsetag_rbm(doi_def,
+ &cipso_ptr[6],
+ secattr);
+ break;
+ case CIPSO_V4_TAG_ENUM:
+ ret_val = cipso_v4_parsetag_enum(doi_def,
+ &cipso_ptr[6],
+ secattr);
+ break;
+ case CIPSO_V4_TAG_RANGE:
+ ret_val = cipso_v4_parsetag_rng(doi_def,
+ &cipso_ptr[6],
+ secattr);
+ break;
+ }
+ rcu_read_unlock();
+
+ return ret_val;
+}
+
+/**
+ * cipso_v4_socket_getattr - Get the security attributes from a socket
+ * @sock: the socket
+ * @secattr: the security attributes
+ *
+ * Description:
+ * Query @sock to see if there is a CIPSO option attached to the socket and if
+ * there is return the CIPSO security attributes in @secattr. Returns zero on
+ * success and negative values on failure.
+ *
+ */
+int cipso_v4_socket_getattr(const struct socket *sock,
+ struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val;
+
+ lock_sock(sock->sk);
+ ret_val = cipso_v4_sock_getattr(sock->sk, secattr);
+ release_sock(sock->sk);
+
+ return ret_val;
+}
+
+/**
+ * cipso_v4_skbuff_getattr - Get the security attributes from the CIPSO option
+ * @skb: the packet
+ * @secattr: the security attributes
+ *
+ * Description:
+ * Parse the given packet's CIPSO option and return the security attributes.
+ * Returns zero on success and negative values on failure.
+ *
+ */
+int cipso_v4_skbuff_getattr(const struct sk_buff *skb,
+ struct netlbl_lsm_secattr *secattr)
+{
+ int ret_val = -ENOMSG;
+ unsigned char *cipso_ptr;
+ u32 doi;
+ struct cipso_v4_doi *doi_def;
+
+ cipso_ptr = CIPSO_V4_OPTPTR(skb);
+ if (cipso_v4_cache_check(cipso_ptr, cipso_ptr[1], secattr) == 0)
+ return 0;
+
+ doi = ntohl(*(__be32 *)&cipso_ptr[2]);
+ rcu_read_lock();
+ doi_def = cipso_v4_doi_search(doi);
+ if (doi_def == NULL)
+ goto skbuff_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_ptr[6]) {
+ case CIPSO_V4_TAG_RBITMAP:
+ ret_val = cipso_v4_parsetag_rbm(doi_def,
+ &cipso_ptr[6],
+ secattr);
+ break;
+ case CIPSO_V4_TAG_ENUM:
+ ret_val = cipso_v4_parsetag_enum(doi_def,
+ &cipso_ptr[6],
+ secattr);
+ break;
+ }
+
+skbuff_getattr_return:
+ rcu_read_unlock();
+ return ret_val;
+}
+
+/*
+ * Setup Functions
+ */
+
+/**
+ * cipso_v4_init - Initialize the CIPSO module
+ *
+ * Description:
+ * Initialize the CIPSO module and prepare it for use. Returns zero on success
+ * and negative values on failure.
+ *
+ */
+static int __init cipso_v4_init(void)
+{
+ int ret_val;
+
+ ret_val = cipso_v4_cache_init();
+ if (ret_val != 0)
+ panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
+ ret_val);
+
+ return 0;
+}
+
+subsys_initcall(cipso_v4_init);
git://git.onelab.eu / linux-2.6.git / blobdiff