/*
* 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_INVALID:
if (iter == 0)
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) {
*net_lvl = doi_def->map.std->lvl.local[host_lvl];
return 0;
}
break;
}
return -EINVAL;
}
/**
* cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
* @doi_def: the DOI definition
* @net_lvl: the network/CIPSO MLS level
* @host_lvl: the host MLS level
*
* Description:
* Perform a label mapping to translate a CIPSO level to the correct local MLS
* level using the given DOI definition. Returns zero on success, negative
* values otherwise.
*
*/
static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
u32 net_lvl,
u32 *host_lvl)
{
struct cipso_v4_std_map_tbl *map_tbl;
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
*host_lvl = net_lvl;
return 0;
case CIPSO_V4_MAP_STD:
map_tbl = doi_def->map.std;
if (net_lvl < map_tbl->lvl.cipso_size &&
map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
*host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
return 0;
}
break;
}
return -EINVAL;
}
/**
* cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
* @doi_def: the DOI definition
* @bitmap: category bitmap
* @bitmap_len: bitmap length in bytes
*
* Description:
* Checks the given category bitmap against the given DOI definition and
* returns a negative value if any of the categories in the bitmap do not have
* a valid mapping and a zero value if all of the categories are valid.
*
*/
static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
const unsigned char *bitmap,
u32 bitmap_len)
{
int cat = -1;
u32 bitmap_len_bits = bitmap_len * 8;
u32 cipso_cat_size;
u32 *cipso_array;
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
return 0;
case CIPSO_V4_MAP_STD:
cipso_cat_size = doi_def->map.std->cat.cipso_size;
cipso_array = doi_def->map.std->cat.cipso;
for (;;) {
cat = cipso_v4_bitmap_walk(bitmap,
bitmap_len_bits,
cat + 1,
1);
if (cat < 0)
break;
if (cat >= cipso_cat_size ||
cipso_array[cat] >= CIPSO_V4_INV_CAT)
return -EFAULT;
}
if (cat == -1)
return 0;
break;
}
return -EFAULT;
}
/**
* cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
* @doi_def: the DOI definition
* @host_cat: the category bitmap in host format
* @host_cat_len: the length of the host's category bitmap in bytes
* @net_cat: the zero'd out category bitmap in network/CIPSO format
* @net_cat_len: the length of the CIPSO bitmap in bytes
*
* Description:
* Perform a label mapping to translate a local MLS category bitmap to the
* correct CIPSO bitmap using the given DOI definition. Returns the minimum
* size in bytes of the network bitmap on success, negative values otherwise.
*
*/
static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
const unsigned char *host_cat,
u32 host_cat_len,
unsigned char *net_cat,
u32 net_cat_len)
{
int host_spot = -1;
u32 net_spot;
u32 net_spot_max = 0;
u32 host_clen_bits = host_cat_len * 8;
u32 net_clen_bits = net_cat_len * 8;
u32 host_cat_size;
u32 *host_cat_array;
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
net_spot_max = host_cat_len;
while (net_spot_max > 0 && host_cat[net_spot_max - 1] == 0)
net_spot_max--;
if (net_spot_max > net_cat_len)
return -EINVAL;
memcpy(net_cat, host_cat, net_spot_max);
return net_spot_max;
case CIPSO_V4_MAP_STD:
host_cat_size = doi_def->map.std->cat.local_size;
host_cat_array = doi_def->map.std->cat.local;
for (;;) {
host_spot = cipso_v4_bitmap_walk(host_cat,
host_clen_bits,
host_spot + 1,
1);
if (host_spot < 0)
break;
if (host_spot >= host_cat_size)
return -EPERM;
net_spot = host_cat_array[host_spot];
if (net_spot >= net_clen_bits)
return -ENOSPC;
cipso_v4_bitmap_setbit(net_cat, net_spot, 1);
if (net_spot > net_spot_max)
net_spot_max = net_spot;
}
if (host_spot == -2)
return -EFAULT;
if (++net_spot_max % 8)
return net_spot_max / 8 + 1;
return net_spot_max / 8;
}
return -EINVAL;
}
/**
* cipso_v4_map_cat_rbm_ntoh - Perform a category mapping from network to host
* @doi_def: the DOI definition
* @net_cat: the category bitmap in network/CIPSO format
* @net_cat_len: the length of the CIPSO bitmap in bytes
* @host_cat: the zero'd out category bitmap in host format
* @host_cat_len: the length of the host's category bitmap in bytes
*
* Description:
* Perform a label mapping to translate a CIPSO bitmap to the correct local
* MLS category bitmap using the given DOI definition. Returns the minimum
* size in bytes of the host bitmap on success, negative values otherwise.
*
*/
static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
const unsigned char *net_cat,
u32 net_cat_len,
unsigned char *host_cat,
u32 host_cat_len)
{
u32 host_spot;
u32 host_spot_max = 0;
int net_spot = -1;
u32 net_clen_bits = net_cat_len * 8;
u32 host_clen_bits = host_cat_len * 8;
u32 net_cat_size;
u32 *net_cat_array;
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
if (net_cat_len > host_cat_len)
return -EINVAL;
memcpy(host_cat, net_cat, net_cat_len);
return net_cat_len;
case CIPSO_V4_MAP_STD:
net_cat_size = doi_def->map.std->cat.cipso_size;
net_cat_array = doi_def->map.std->cat.cipso;
for (;;) {
net_spot = cipso_v4_bitmap_walk(net_cat,
net_clen_bits,
net_spot + 1,
1);
if (net_spot < 0)
break;
if (net_spot >= net_cat_size ||
net_cat_array[net_spot] >= CIPSO_V4_INV_CAT)
return -EPERM;
host_spot = net_cat_array[net_spot];
if (host_spot >= host_clen_bits)
return -ENOSPC;
cipso_v4_bitmap_setbit(host_cat, host_spot, 1);
if (host_spot > host_spot_max)
host_spot_max = host_spot;
}
if (net_spot == -2)
return -EFAULT;
if (++host_spot_max % 8)
return host_spot_max / 8 + 1;
return host_spot_max / 8;
}
return -EINVAL;
}
/*
* Protocol Handling Functions
*/
#define CIPSO_V4_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->mls_cat,
secattr->mls_cat_len,
&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) {
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
secattr->mls_cat_len = tag_len - 4;
break;
case CIPSO_V4_MAP_STD:
secattr->mls_cat_len =
doi_def->map.std->cat.local_size;
break;
}
secattr->mls_cat = kzalloc(secattr->mls_cat_len, GFP_ATOMIC);
if (secattr->mls_cat == NULL)
return -ENOMEM;
ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
&tag[4],
tag_len - 4,
secattr->mls_cat,
secattr->mls_cat_len);
if (ret_val < 0) {
kfree(secattr->mls_cat);
return ret_val;
} else if (ret_val > 0) {
secattr->mls_cat_len = 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_getdef(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;
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;
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_getdef(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;
}
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_getdef(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;
}
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);
