linux/net/ipv4/cipso_ipv4.c
Paul Moore 04f81f0154 cipso: don't use IPCB() to locate the CIPSO IP option
Using the IPCB() macro to get the IPv4 options is convenient, but
unfortunately NetLabel often needs to examine the CIPSO option outside
of the scope of the IP layer in the stack.  While historically IPCB()
worked above the IP layer, due to the inclusion of the inet_skb_param
struct at the head of the {tcp,udp}_skb_cb structs, recent commit
971f10ec ("tcp: better TCP_SKB_CB layout to reduce cache line misses")
reordered the tcp_skb_cb struct and invalidated this IPCB() trick.

This patch fixes the problem by creating a new function,
cipso_v4_optptr(), which locates the CIPSO option inside the IP header
without calling IPCB().  Unfortunately, this isn't as fast as a simple
lookup so some additional tweaks were made to limit the use of this
new function.

Cc: <stable@vger.kernel.org> # 3.18
Reported-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Tested-by: Casey Schaufler <casey@schaufler-ca.com>
2015-02-11 14:46:37 -05:00

2358 lines
63 KiB
C

/*
* CIPSO - Commercial IP Security Option
*
* This is an implementation of the CIPSO 2.2 protocol as specified in
* draft-ietf-cipso-ipsecurity-01.txt with additional tag types as found in
* FIPS-188. While CIPSO never became a full IETF RFC standard many vendors
* have chosen to adopt the protocol and over the years it has become a
* de-facto standard for labeled networking.
*
* The CIPSO draft specification can be found in the kernel's Documentation
* directory as well as the following URL:
* http://tools.ietf.org/id/draft-ietf-cipso-ipsecurity-01.txt
* The FIPS-188 specification can be found at the following URL:
* http://www.itl.nist.gov/fipspubs/fip188.htm
*
* Author: Paul Moore <paul.moore@hp.com>
*
*/
/*
* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include <linux/init.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/jhash.h>
#include <linux/audit.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/tcp.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <linux/atomic.h>
#include <linux/bug.h>
#include <asm/unaligned.h>
/* List of available DOI definitions */
/* XXX - This currently assumes a minimal number of different DOIs in use,
* if in practice there are a lot of different DOIs this list should
* probably be turned into a hash table or something similar so we
* can do quick lookups. */
static DEFINE_SPINLOCK(cipso_v4_doi_list_lock);
static LIST_HEAD(cipso_v4_doi_list);
/* Label mapping cache */
int cipso_v4_cache_enabled = 1;
int cipso_v4_cache_bucketsize = 10;
#define CIPSO_V4_CACHE_BUCKETBITS 7
#define CIPSO_V4_CACHE_BUCKETS (1 << CIPSO_V4_CACHE_BUCKETBITS)
#define CIPSO_V4_CACHE_REORDERLIMIT 10
struct cipso_v4_map_cache_bkt {
spinlock_t lock;
u32 size;
struct list_head list;
};
struct cipso_v4_map_cache_entry {
u32 hash;
unsigned char *key;
size_t key_len;
struct netlbl_lsm_cache *lsm_data;
u32 activity;
struct list_head list;
};
static struct cipso_v4_map_cache_bkt *cipso_v4_cache;
/* Restricted bitmap (tag #1) flags */
int cipso_v4_rbm_optfmt = 0;
int cipso_v4_rbm_strictvalid = 1;
/*
* Protocol Constants
*/
/* Maximum size of the CIPSO IP option, derived from the fact that the maximum
* IPv4 header size is 60 bytes and the base IPv4 header is 20 bytes long. */
#define CIPSO_V4_OPT_LEN_MAX 40
/* Length of the base CIPSO option, this includes the option type (1 byte), the
* option length (1 byte), and the DOI (4 bytes). */
#define CIPSO_V4_HDR_LEN 6
/* Base length of the restrictive category bitmap tag (tag #1). */
#define CIPSO_V4_TAG_RBM_BLEN 4
/* Base length of the enumerated category tag (tag #2). */
#define CIPSO_V4_TAG_ENUM_BLEN 4
/* Base length of the ranged categories bitmap tag (tag #5). */
#define CIPSO_V4_TAG_RNG_BLEN 4
/* The maximum number of category ranges permitted in the ranged category tag
* (tag #5). You may note that the IETF draft states that the maximum number
* of category ranges is 7, but if the low end of the last category range is
* zero then it is possible to fit 8 category ranges because the zero should
* be omitted. */
#define CIPSO_V4_TAG_RNG_CAT_MAX 8
/* Base length of the local tag (non-standard tag).
* Tag definition (may change between kernel versions)
*
* 0 8 16 24 32
* +----------+----------+----------+----------+
* | 10000000 | 00000110 | 32-bit secid value |
* +----------+----------+----------+----------+
* | in (host byte order)|
* +----------+----------+
*
*/
#define CIPSO_V4_TAG_LOC_BLEN 6
/*
* Helper Functions
*/
/**
* cipso_v4_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_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 == 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);
}
}
/**
* cipso_v4_cache_check - Check the CIPSO cache for a label mapping
* @key: the buffer to check
* @key_len: buffer length in bytes
* @secattr: the security attribute struct to use
*
* Description:
* This function checks the cache to see if a label mapping already exists for
* the given key. If there is a match then the cache is adjusted and the
* @secattr struct is populated with the correct LSM security attributes. The
* cache is adjusted in the following manner if the entry is not already the
* first in the cache bucket:
*
* 1. The cache entry's activity counter is incremented
* 2. The previous (higher ranking) entry's activity counter is decremented
* 3. If the difference between the two activity counters is geater than
* CIPSO_V4_CACHE_REORDERLIMIT the two entries are swapped
*
* Returns zero on success, -ENOENT for a cache miss, and other negative values
* on error.
*
*/
static int cipso_v4_cache_check(const unsigned char *key,
u32 key_len,
struct netlbl_lsm_secattr *secattr)
{
u32 bkt;
struct cipso_v4_map_cache_entry *entry;
struct cipso_v4_map_cache_entry *prev_entry = NULL;
u32 hash;
if (!cipso_v4_cache_enabled)
return -ENOENT;
hash = cipso_v4_map_cache_hash(key, key_len);
bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
spin_lock_bh(&cipso_v4_cache[bkt].lock);
list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
if (entry->hash == hash &&
entry->key_len == key_len &&
memcmp(entry->key, key, key_len) == 0) {
entry->activity += 1;
atomic_inc(&entry->lsm_data->refcount);
secattr->cache = entry->lsm_data;
secattr->flags |= NETLBL_SECATTR_CACHE;
secattr->type = NETLBL_NLTYPE_CIPSOV4;
if (prev_entry == 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 unsigned char *cipso_ptr,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val = -EPERM;
u32 bkt;
struct cipso_v4_map_cache_entry *entry = NULL;
struct cipso_v4_map_cache_entry *old_entry = NULL;
u32 cipso_ptr_len;
if (!cipso_v4_cache_enabled || cipso_v4_cache_bucketsize <= 0)
return 0;
cipso_ptr_len = cipso_ptr[1];
entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
if (entry == 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_BUCKETS - 1);
spin_lock_bh(&cipso_v4_cache[bkt].lock);
if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) {
list_add(&entry->list, &cipso_v4_cache[bkt].list);
cipso_v4_cache[bkt].size += 1;
} else {
old_entry = list_entry(cipso_v4_cache[bkt].list.prev,
struct cipso_v4_map_cache_entry, list);
list_del(&old_entry->list);
list_add(&entry->list, &cipso_v4_cache[bkt].list);
cipso_v4_cache_entry_free(old_entry);
}
spin_unlock_bh(&cipso_v4_cache[bkt].lock);
return 0;
cache_add_failure:
if (entry)
cipso_v4_cache_entry_free(entry);
return ret_val;
}
/*
* DOI List Functions
*/
/**
* cipso_v4_doi_search - Searches for a DOI definition
* @doi: the DOI to search for
*
* Description:
* Search the DOI definition list for a DOI definition with a DOI value that
* matches @doi. The caller is responsible for calling rcu_read_[un]lock().
* Returns a pointer to the DOI definition on success and NULL on failure.
*/
static struct cipso_v4_doi *cipso_v4_doi_search(u32 doi)
{
struct cipso_v4_doi *iter;
list_for_each_entry_rcu(iter, &cipso_v4_doi_list, list)
if (iter->doi == doi && atomic_read(&iter->refcount))
return iter;
return NULL;
}
/**
* cipso_v4_doi_add - Add a new DOI to the CIPSO protocol engine
* @doi_def: the DOI structure
* @audit_info: NetLabel audit information
*
* Description:
* The caller defines a new DOI for use by the CIPSO engine and calls this
* function to add it to the list of acceptable domains. The caller must
* ensure that the mapping table specified in @doi_def->map meets all of the
* requirements of the mapping type (see cipso_ipv4.h for details). Returns
* zero on success and non-zero on failure.
*
*/
int cipso_v4_doi_add(struct cipso_v4_doi *doi_def,
struct netlbl_audit *audit_info)
{
int ret_val = -EINVAL;
u32 iter;
u32 doi;
u32 doi_type;
struct audit_buffer *audit_buf;
doi = doi_def->doi;
doi_type = doi_def->type;
if (doi_def->doi == CIPSO_V4_DOI_UNKNOWN)
goto doi_add_return;
for (iter = 0; iter < CIPSO_V4_TAG_MAXCNT; iter++) {
switch (doi_def->tags[iter]) {
case CIPSO_V4_TAG_RBITMAP:
break;
case CIPSO_V4_TAG_RANGE:
case CIPSO_V4_TAG_ENUM:
if (doi_def->type != CIPSO_V4_MAP_PASS)
goto doi_add_return;
break;
case CIPSO_V4_TAG_LOCAL:
if (doi_def->type != CIPSO_V4_MAP_LOCAL)
goto doi_add_return;
break;
case CIPSO_V4_TAG_INVALID:
if (iter == 0)
goto doi_add_return;
break;
default:
goto doi_add_return;
}
}
atomic_set(&doi_def->refcount, 1);
spin_lock(&cipso_v4_doi_list_lock);
if (cipso_v4_doi_search(doi_def->doi) != NULL) {
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 != NULL) {
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 == NULL)
return;
switch (doi_def->type) {
case CIPSO_V4_MAP_TRANS:
kfree(doi_def->map.std->lvl.cipso);
kfree(doi_def->map.std->lvl.local);
kfree(doi_def->map.std->cat.cipso);
kfree(doi_def->map.std->cat.local);
break;
}
kfree(doi_def);
}
/**
* cipso_v4_doi_free_rcu - Frees a DOI definition via the RCU pointer
* @entry: the entry's RCU field
*
* Description:
* This function is designed to be used as a callback to the call_rcu()
* function so that the memory allocated to the DOI definition can be released
* safely.
*
*/
static void cipso_v4_doi_free_rcu(struct rcu_head *entry)
{
struct cipso_v4_doi *doi_def;
doi_def = container_of(entry, struct cipso_v4_doi, rcu);
cipso_v4_doi_free(doi_def);
}
/**
* cipso_v4_doi_remove - Remove an existing DOI from the CIPSO protocol engine
* @doi: the DOI value
* @audit_secid: the LSM secid to use in the audit message
*
* Description:
* Removes a DOI definition from the CIPSO engine. The NetLabel routines will
* be called to release their own LSM domain mappings as well as our own
* domain list. Returns zero on success and negative values on failure.
*
*/
int cipso_v4_doi_remove(u32 doi, struct netlbl_audit *audit_info)
{
int ret_val;
struct cipso_v4_doi *doi_def;
struct audit_buffer *audit_buf;
spin_lock(&cipso_v4_doi_list_lock);
doi_def = cipso_v4_doi_search(doi);
if (doi_def == NULL) {
spin_unlock(&cipso_v4_doi_list_lock);
ret_val = -ENOENT;
goto doi_remove_return;
}
if (!atomic_dec_and_test(&doi_def->refcount)) {
spin_unlock(&cipso_v4_doi_list_lock);
ret_val = -EBUSY;
goto doi_remove_return;
}
list_del_rcu(&doi_def->list);
spin_unlock(&cipso_v4_doi_list_lock);
cipso_v4_cache_invalidate();
call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
ret_val = 0;
doi_remove_return:
audit_buf = netlbl_audit_start(AUDIT_MAC_CIPSOV4_DEL, audit_info);
if (audit_buf != NULL) {
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 == NULL)
goto doi_getdef_return;
if (!atomic_inc_not_zero(&doi_def->refcount))
doi_def = NULL;
doi_getdef_return:
rcu_read_unlock();
return doi_def;
}
/**
* cipso_v4_doi_putdef - Releases a reference for the given DOI definition
* @doi_def: the DOI definition
*
* Description:
* Releases a DOI definition reference obtained from cipso_v4_doi_getdef().
*
*/
void cipso_v4_doi_putdef(struct cipso_v4_doi *doi_def)
{
if (doi_def == NULL)
return;
if (!atomic_dec_and_test(&doi_def->refcount))
return;
spin_lock(&cipso_v4_doi_list_lock);
list_del_rcu(&doi_def->list);
spin_unlock(&cipso_v4_doi_list_lock);
cipso_v4_cache_invalidate();
call_rcu(&doi_def->rcu, cipso_v4_doi_free_rcu);
}
/**
* cipso_v4_doi_walk - Iterate through the DOI definitions
* @skip_cnt: skip past this number of DOI definitions, updated
* @callback: callback for each DOI definition
* @cb_arg: argument for the callback function
*
* Description:
* Iterate over the DOI definition list, skipping the first @skip_cnt entries.
* For each entry call @callback, if @callback returns a negative value stop
* 'walking' through the list and return. Updates the value in @skip_cnt upon
* return. Returns zero on success, negative values on failure.
*
*/
int cipso_v4_doi_walk(u32 *skip_cnt,
int (*callback) (struct cipso_v4_doi *doi_def, void *arg),
void *cb_arg)
{
int ret_val = -ENOENT;
u32 doi_cnt = 0;
struct cipso_v4_doi *iter_doi;
rcu_read_lock();
list_for_each_entry_rcu(iter_doi, &cipso_v4_doi_list, list)
if (atomic_read(&iter_doi->refcount) > 0) {
if (doi_cnt++ < *skip_cnt)
continue;
ret_val = callback(iter_doi, cb_arg);
if (ret_val < 0) {
doi_cnt--;
goto doi_walk_return;
}
}
doi_walk_return:
rcu_read_unlock();
*skip_cnt = doi_cnt;
return ret_val;
}
/*
* Label Mapping Functions
*/
/**
* cipso_v4_map_lvl_valid - Checks to see if the given level is understood
* @doi_def: the DOI definition
* @level: the level to check
*
* Description:
* Checks the given level against the given DOI definition and returns a
* negative value if the level does not have a valid mapping and a zero value
* if the level is defined by the DOI.
*
*/
static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
{
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
return 0;
case CIPSO_V4_MAP_TRANS:
if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL)
return 0;
break;
}
return -EFAULT;
}
/**
* cipso_v4_map_lvl_hton - Perform a level mapping from the host to the network
* @doi_def: the DOI definition
* @host_lvl: the host MLS level
* @net_lvl: the network/CIPSO MLS level
*
* Description:
* Perform a label mapping to translate a local MLS level to the correct
* CIPSO level using the given DOI definition. Returns zero on success,
* negative values otherwise.
*
*/
static int cipso_v4_map_lvl_hton(const struct cipso_v4_doi *doi_def,
u32 host_lvl,
u32 *net_lvl)
{
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
*net_lvl = host_lvl;
return 0;
case CIPSO_V4_MAP_TRANS:
if (host_lvl < doi_def->map.std->lvl.local_size &&
doi_def->map.std->lvl.local[host_lvl] < CIPSO_V4_INV_LVL) {
*net_lvl = doi_def->map.std->lvl.local[host_lvl];
return 0;
}
return -EPERM;
}
return -EINVAL;
}
/**
* cipso_v4_map_lvl_ntoh - Perform a level mapping from the network to the host
* @doi_def: the DOI definition
* @net_lvl: the network/CIPSO MLS level
* @host_lvl: the host MLS level
*
* Description:
* Perform a label mapping to translate a CIPSO level to the correct local MLS
* level using the given DOI definition. Returns zero on success, negative
* values otherwise.
*
*/
static int cipso_v4_map_lvl_ntoh(const struct cipso_v4_doi *doi_def,
u32 net_lvl,
u32 *host_lvl)
{
struct cipso_v4_std_map_tbl *map_tbl;
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
*host_lvl = net_lvl;
return 0;
case CIPSO_V4_MAP_TRANS:
map_tbl = doi_def->map.std;
if (net_lvl < map_tbl->lvl.cipso_size &&
map_tbl->lvl.cipso[net_lvl] < CIPSO_V4_INV_LVL) {
*host_lvl = doi_def->map.std->lvl.cipso[net_lvl];
return 0;
}
return -EPERM;
}
return -EINVAL;
}
/**
* cipso_v4_map_cat_rbm_valid - Checks to see if the category bitmap is valid
* @doi_def: the DOI definition
* @bitmap: category bitmap
* @bitmap_len: bitmap length in bytes
*
* Description:
* Checks the given category bitmap against the given DOI definition and
* returns a negative value if any of the categories in the bitmap do not have
* a valid mapping and a zero value if all of the categories are valid.
*
*/
static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
const unsigned char *bitmap,
u32 bitmap_len)
{
int cat = -1;
u32 bitmap_len_bits = bitmap_len * 8;
u32 cipso_cat_size;
u32 *cipso_array;
switch (doi_def->type) {
case CIPSO_V4_MAP_PASS:
return 0;
case CIPSO_V4_MAP_TRANS:
cipso_cat_size = doi_def->map.std->cat.cipso_size;
cipso_array = doi_def->map.std->cat.cipso;
for (;;) {
cat = 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_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;
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_TRANS) {
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_TRANS:
if (net_spot >= net_cat_size)
return -EPERM;
host_spot = net_cat_array[net_spot];
if (host_spot >= CIPSO_V4_INV_CAT)
return -EPERM;
break;
}
ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
host_spot,
GFP_ATOMIC);
if (ret_val != 0)
return ret_val;
}
return -EINVAL;
}
/**
* cipso_v4_map_cat_enum_valid - Checks to see if the categories are valid
* @doi_def: the DOI definition
* @enumcat: category list
* @enumcat_len: length of the category list in bytes
*
* Description:
* Checks the given categories against the given DOI definition and returns a
* negative value if any of the categories do not have a valid mapping and a
* zero value if all of the categories are valid.
*
*/
static int cipso_v4_map_cat_enum_valid(const struct cipso_v4_doi *doi_def,
const unsigned char *enumcat,
u32 enumcat_len)
{
u16 cat;
int cat_prev = -1;
u32 iter;
if (doi_def->type != CIPSO_V4_MAP_PASS || enumcat_len & 0x01)
return -EFAULT;
for (iter = 0; iter < enumcat_len; iter += 2) {
cat = get_unaligned_be16(&enumcat[iter]);
if (cat <= cat_prev)
return -EFAULT;
cat_prev = cat;
}
return 0;
}
/**
* cipso_v4_map_cat_enum_hton - Perform a category mapping from host to network
* @doi_def: the DOI definition
* @secattr: the security attributes
* @net_cat: the zero'd out category list in network/CIPSO format
* @net_cat_len: the length of the CIPSO category list in bytes
*
* Description:
* Perform a label mapping to translate a local MLS category bitmap to the
* correct CIPSO category list using the given DOI definition. Returns the
* size in bytes of the network category bitmap on success, negative values
* otherwise.
*
*/
static int cipso_v4_map_cat_enum_hton(const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr,
unsigned char *net_cat,
u32 net_cat_len)
{
int cat = -1;
u32 cat_iter = 0;
for (;;) {
cat = netlbl_catmap_walk(secattr->attr.mls.cat, cat + 1);
if (cat < 0)
break;
if ((cat_iter + 2) > net_cat_len)
return -ENOSPC;
*((__be16 *)&net_cat[cat_iter]) = htons(cat);
cat_iter += 2;
}
return cat_iter;
}
/**
* cipso_v4_map_cat_enum_ntoh - Perform a category mapping from network to host
* @doi_def: the DOI definition
* @net_cat: the category list in network/CIPSO format
* @net_cat_len: the length of the CIPSO bitmap in bytes
* @secattr: the security attributes
*
* Description:
* Perform a label mapping to translate a CIPSO category list to the correct
* local MLS category bitmap using the given DOI definition. Returns zero on
* success, negative values on failure.
*
*/
static int cipso_v4_map_cat_enum_ntoh(const struct cipso_v4_doi *doi_def,
const unsigned char *net_cat,
u32 net_cat_len,
struct netlbl_lsm_secattr *secattr)
{
int ret_val;
u32 iter;
for (iter = 0; iter < net_cat_len; iter += 2) {
ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat,
get_unaligned_be16(&net_cat[iter]),
GFP_ATOMIC);
if (ret_val != 0)
return ret_val;
}
return 0;
}
/**
* cipso_v4_map_cat_rng_valid - Checks to see if the categories are valid
* @doi_def: the DOI definition
* @rngcat: category list
* @rngcat_len: length of the category list in bytes
*
* Description:
* Checks the given categories against the given DOI definition and returns a
* negative value if any of the categories do not have a valid mapping and a
* zero value if all of the categories are valid.
*
*/
static int cipso_v4_map_cat_rng_valid(const struct cipso_v4_doi *doi_def,
const unsigned char *rngcat,
u32 rngcat_len)
{
u16 cat_high;
u16 cat_low;
u32 cat_prev = CIPSO_V4_MAX_REM_CATS + 1;
u32 iter;
if (doi_def->type != CIPSO_V4_MAP_PASS || rngcat_len & 0x01)
return -EFAULT;
for (iter = 0; iter < rngcat_len; iter += 4) {
cat_high = get_unaligned_be16(&rngcat[iter]);
if ((iter + 4) <= rngcat_len)
cat_low = get_unaligned_be16(&rngcat[iter + 2]);
else
cat_low = 0;
if (cat_high > cat_prev)
return -EFAULT;
cat_prev = cat_low;
}
return 0;
}
/**
* cipso_v4_map_cat_rng_hton - Perform a category mapping from host to network
* @doi_def: the DOI definition
* @secattr: the security attributes
* @net_cat: the zero'd out category list in network/CIPSO format
* @net_cat_len: the length of the CIPSO category list in bytes
*
* Description:
* Perform a label mapping to translate a local MLS category bitmap to the
* correct CIPSO category list using the given DOI definition. Returns the
* size in bytes of the network category bitmap on success, negative values
* otherwise.
*
*/
static int cipso_v4_map_cat_rng_hton(const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr,
unsigned char *net_cat,
u32 net_cat_len)
{
int iter = -1;
u16 array[CIPSO_V4_TAG_RNG_CAT_MAX * 2];
u32 array_cnt = 0;
u32 cat_size = 0;
/* make sure we don't overflow the 'array[]' variable */
if (net_cat_len >
(CIPSO_V4_OPT_LEN_MAX - CIPSO_V4_HDR_LEN - CIPSO_V4_TAG_RNG_BLEN))
return -ENOSPC;
for (;;) {
iter = netlbl_catmap_walk(secattr->attr.mls.cat, iter + 1);
if (iter < 0)
break;
cat_size += (iter == 0 ? 0 : sizeof(u16));
if (cat_size > net_cat_len)
return -ENOSPC;
array[array_cnt++] = iter;
iter = netlbl_catmap_walkrng(secattr->attr.mls.cat, iter);
if (iter < 0)
return -EFAULT;
cat_size += sizeof(u16);
if (cat_size > net_cat_len)
return -ENOSPC;
array[array_cnt++] = iter;
}
for (iter = 0; array_cnt > 0;) {
*((__be16 *)&net_cat[iter]) = htons(array[--array_cnt]);
iter += 2;
array_cnt--;
if (array[array_cnt] != 0) {
*((__be16 *)&net_cat[iter]) = htons(array[array_cnt]);
iter += 2;
}
}
return cat_size;
}
/**
* cipso_v4_map_cat_rng_ntoh - Perform a category mapping from network to host
* @doi_def: the DOI definition
* @net_cat: the category list in network/CIPSO format
* @net_cat_len: the length of the CIPSO bitmap in bytes
* @secattr: the security attributes
*
* Description:
* Perform a label mapping to translate a CIPSO category list to the correct
* local MLS category bitmap using the given DOI definition. Returns zero on
* success, negative values on failure.
*
*/
static int cipso_v4_map_cat_rng_ntoh(const struct cipso_v4_doi *doi_def,
const unsigned char *net_cat,
u32 net_cat_len,
struct netlbl_lsm_secattr *secattr)
{
int ret_val;
u32 net_iter;
u16 cat_low;
u16 cat_high;
for (net_iter = 0; net_iter < net_cat_len; net_iter += 4) {
cat_high = get_unaligned_be16(&net_cat[net_iter]);
if ((net_iter + 4) <= net_cat_len)
cat_low = get_unaligned_be16(&net_cat[net_iter + 2]);
else
cat_low = 0;
ret_val = netlbl_catmap_setrng(&secattr->attr.mls.cat,
cat_low,
cat_high,
GFP_ATOMIC);
if (ret_val != 0)
return ret_val;
}
return 0;
}
/*
* Protocol Handling Functions
*/
/**
* cipso_v4_gentag_hdr - Generate a CIPSO option header
* @doi_def: the DOI definition
* @len: the total tag length in bytes, not including this header
* @buf: the CIPSO option buffer
*
* Description:
* Write a CIPSO header into the beginning of @buffer.
*
*/
static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
unsigned char *buf,
u32 len)
{
buf[0] = IPOPT_CIPSO;
buf[1] = CIPSO_V4_HDR_LEN + len;
*(__be32 *)&buf[2] = htonl(doi_def->doi);
}
/**
* cipso_v4_gentag_rbm - Generate a CIPSO restricted bitmap tag (type #1)
* @doi_def: the DOI definition
* @secattr: the security attributes
* @buffer: the option buffer
* @buffer_len: length of buffer in bytes
*
* Description:
* Generate a CIPSO option using the restricted bitmap tag, tag type #1. The
* actual buffer length may be larger than the indicated size due to
* translation between host and network category bitmaps. Returns the size of
* the tag on success, negative values on failure.
*
*/
static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr,
unsigned char *buffer,
u32 buffer_len)
{
int ret_val;
u32 tag_len;
u32 level;
if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0)
return -EPERM;
ret_val = cipso_v4_map_lvl_hton(doi_def,
secattr->attr.mls.lvl,
&level);
if (ret_val != 0)
return ret_val;
if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
secattr,
&buffer[4],
buffer_len - 4);
if (ret_val < 0)
return ret_val;
/* This will send packets using the "optimized" format when
* possible as specified in section 3.4.2.6 of the
* CIPSO draft. */
if (cipso_v4_rbm_optfmt && ret_val > 0 && ret_val <= 10)
tag_len = 14;
else
tag_len = 4 + ret_val;
} else
tag_len = 4;
buffer[0] = CIPSO_V4_TAG_RBITMAP;
buffer[1] = tag_len;
buffer[3] = level;
return tag_len;
}
/**
* cipso_v4_parsetag_rbm - Parse a CIPSO restricted bitmap tag
* @doi_def: the DOI definition
* @tag: the CIPSO tag
* @secattr: the security attributes
*
* Description:
* Parse a CIPSO restricted bitmap tag (tag type #1) and return the security
* attributes in @secattr. Return zero on success, negatives values on
* failure.
*
*/
static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
const unsigned char *tag,
struct netlbl_lsm_secattr *secattr)
{
int ret_val;
u8 tag_len = tag[1];
u32 level;
ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
if (ret_val != 0)
return ret_val;
secattr->attr.mls.lvl = level;
secattr->flags |= NETLBL_SECATTR_MLS_LVL;
if (tag_len > 4) {
ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
&tag[4],
tag_len - 4,
secattr);
if (ret_val != 0) {
netlbl_catmap_free(secattr->attr.mls.cat);
return ret_val;
}
secattr->flags |= NETLBL_SECATTR_MLS_CAT;
}
return 0;
}
/**
* cipso_v4_gentag_enum - Generate a CIPSO enumerated tag (type #2)
* @doi_def: the DOI definition
* @secattr: the security attributes
* @buffer: the option buffer
* @buffer_len: length of buffer in bytes
*
* Description:
* Generate a CIPSO option using the enumerated tag, tag type #2. Returns the
* size of the tag on success, negative values on failure.
*
*/
static int cipso_v4_gentag_enum(const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr,
unsigned char *buffer,
u32 buffer_len)
{
int ret_val;
u32 tag_len;
u32 level;
if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
return -EPERM;
ret_val = cipso_v4_map_lvl_hton(doi_def,
secattr->attr.mls.lvl,
&level);
if (ret_val != 0)
return ret_val;
if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
ret_val = cipso_v4_map_cat_enum_hton(doi_def,
secattr,
&buffer[4],
buffer_len - 4);
if (ret_val < 0)
return ret_val;
tag_len = 4 + ret_val;
} else
tag_len = 4;
buffer[0] = CIPSO_V4_TAG_ENUM;
buffer[1] = tag_len;
buffer[3] = level;
return tag_len;
}
/**
* cipso_v4_parsetag_enum - Parse a CIPSO enumerated tag
* @doi_def: the DOI definition
* @tag: the CIPSO tag
* @secattr: the security attributes
*
* Description:
* Parse a CIPSO enumerated tag (tag type #2) and return the security
* attributes in @secattr. Return zero on success, negatives values on
* failure.
*
*/
static int cipso_v4_parsetag_enum(const struct cipso_v4_doi *doi_def,
const unsigned char *tag,
struct netlbl_lsm_secattr *secattr)
{
int ret_val;
u8 tag_len = tag[1];
u32 level;
ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
if (ret_val != 0)
return ret_val;
secattr->attr.mls.lvl = level;
secattr->flags |= NETLBL_SECATTR_MLS_LVL;
if (tag_len > 4) {
ret_val = cipso_v4_map_cat_enum_ntoh(doi_def,
&tag[4],
tag_len - 4,
secattr);
if (ret_val != 0) {
netlbl_catmap_free(secattr->attr.mls.cat);
return ret_val;
}
secattr->flags |= NETLBL_SECATTR_MLS_CAT;
}
return 0;
}
/**
* cipso_v4_gentag_rng - Generate a CIPSO ranged tag (type #5)
* @doi_def: the DOI definition
* @secattr: the security attributes
* @buffer: the option buffer
* @buffer_len: length of buffer in bytes
*
* Description:
* Generate a CIPSO option using the ranged tag, tag type #5. Returns the
* size of the tag on success, negative values on failure.
*
*/
static int cipso_v4_gentag_rng(const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr,
unsigned char *buffer,
u32 buffer_len)
{
int ret_val;
u32 tag_len;
u32 level;
if (!(secattr->flags & NETLBL_SECATTR_MLS_LVL))
return -EPERM;
ret_val = cipso_v4_map_lvl_hton(doi_def,
secattr->attr.mls.lvl,
&level);
if (ret_val != 0)
return ret_val;
if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
ret_val = cipso_v4_map_cat_rng_hton(doi_def,
secattr,
&buffer[4],
buffer_len - 4);
if (ret_val < 0)
return ret_val;
tag_len = 4 + ret_val;
} else
tag_len = 4;
buffer[0] = CIPSO_V4_TAG_RANGE;
buffer[1] = tag_len;
buffer[3] = level;
return tag_len;
}
/**
* cipso_v4_parsetag_rng - Parse a CIPSO ranged tag
* @doi_def: the DOI definition
* @tag: the CIPSO tag
* @secattr: the security attributes
*
* Description:
* Parse a CIPSO ranged tag (tag type #5) and return the security attributes
* in @secattr. Return zero on success, negatives values on failure.
*
*/
static int cipso_v4_parsetag_rng(const struct cipso_v4_doi *doi_def,
const unsigned char *tag,
struct netlbl_lsm_secattr *secattr)
{
int ret_val;
u8 tag_len = tag[1];
u32 level;
ret_val = cipso_v4_map_lvl_ntoh(doi_def, tag[3], &level);
if (ret_val != 0)
return ret_val;
secattr->attr.mls.lvl = level;
secattr->flags |= NETLBL_SECATTR_MLS_LVL;
if (tag_len > 4) {
ret_val = cipso_v4_map_cat_rng_ntoh(doi_def,
&tag[4],
tag_len - 4,
secattr);
if (ret_val != 0) {
netlbl_catmap_free(secattr->attr.mls.cat);
return ret_val;
}
secattr->flags |= NETLBL_SECATTR_MLS_CAT;
}
return 0;
}
/**
* cipso_v4_gentag_loc - Generate a CIPSO local tag (non-standard)
* @doi_def: the DOI definition
* @secattr: the security attributes
* @buffer: the option buffer
* @buffer_len: length of buffer in bytes
*
* Description:
* Generate a CIPSO option using the local tag. Returns the size of the tag
* on success, negative values on failure.
*
*/
static int cipso_v4_gentag_loc(const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr,
unsigned char *buffer,
u32 buffer_len)
{
if (!(secattr->flags & NETLBL_SECATTR_SECID))
return -EPERM;
buffer[0] = CIPSO_V4_TAG_LOCAL;
buffer[1] = CIPSO_V4_TAG_LOC_BLEN;
*(u32 *)&buffer[2] = secattr->attr.secid;
return CIPSO_V4_TAG_LOC_BLEN;
}
/**
* cipso_v4_parsetag_loc - Parse a CIPSO local tag
* @doi_def: the DOI definition
* @tag: the CIPSO tag
* @secattr: the security attributes
*
* Description:
* Parse a CIPSO local tag and return the security attributes in @secattr.
* Return zero on success, negatives values on failure.
*
*/
static int cipso_v4_parsetag_loc(const struct cipso_v4_doi *doi_def,
const unsigned char *tag,
struct netlbl_lsm_secattr *secattr)
{
secattr->attr.secid = *(u32 *)&tag[2];
secattr->flags |= NETLBL_SECATTR_SECID;
return 0;
}
/**
* cipso_v4_optptr - Find the CIPSO option in the packet
* @skb: the packet
*
* Description:
* Parse the packet's IP header looking for a CIPSO option. Returns a pointer
* to the start of the CIPSO option on success, NULL if one if not found.
*
*/
unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
{
const struct iphdr *iph = ip_hdr(skb);
unsigned char *optptr = (unsigned char *)&(ip_hdr(skb)[1]);
int optlen;
int taglen;
for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) {
if (optptr[0] == IPOPT_CIPSO)
return optptr;
taglen = optptr[1];
optlen -= taglen;
optptr += taglen;
}
return NULL;
}
/**
* cipso_v4_validate - Validate a CIPSO option
* @option: the start of the option, on error it is set to point to the error
*
* Description:
* This routine is called to validate a CIPSO option, it checks all of the
* fields to ensure that they are at least valid, see the draft snippet below
* for details. If the option is valid then a zero value is returned and
* the value of @option is unchanged. If the option is invalid then a
* non-zero value is returned and @option is adjusted to point to the
* offending portion of the option. From the IETF draft ...
*
* "If any field within the CIPSO options, such as the DOI identifier, is not
* recognized the IP datagram is discarded and an ICMP 'parameter problem'
* (type 12) is generated and returned. The ICMP code field is set to 'bad
* parameter' (code 0) and the pointer is set to the start of the CIPSO field
* that is unrecognized."
*
*/
int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
{
unsigned char *opt = *option;
unsigned char *tag;
unsigned char opt_iter;
unsigned char err_offset = 0;
u8 opt_len;
u8 tag_len;
struct cipso_v4_doi *doi_def = NULL;
u32 tag_iter;
/* caller already checks for length values that are too large */
opt_len = opt[1];
if (opt_len < 8) {
err_offset = 1;
goto validate_return;
}
rcu_read_lock();
doi_def = cipso_v4_doi_search(get_unaligned_be32(&opt[2]));
if (doi_def == NULL) {
err_offset = 2;
goto validate_return_locked;
}
opt_iter = CIPSO_V4_HDR_LEN;
tag = opt + opt_iter;
while (opt_iter < opt_len) {
for (tag_iter = 0; doi_def->tags[tag_iter] != tag[0];)
if (doi_def->tags[tag_iter] == CIPSO_V4_TAG_INVALID ||
++tag_iter == CIPSO_V4_TAG_MAXCNT) {
err_offset = opt_iter;
goto validate_return_locked;
}
tag_len = tag[1];
if (tag_len > (opt_len - opt_iter)) {
err_offset = opt_iter + 1;
goto validate_return_locked;
}
switch (tag[0]) {
case CIPSO_V4_TAG_RBITMAP:
if (tag_len < CIPSO_V4_TAG_RBM_BLEN) {
err_offset = opt_iter + 1;
goto validate_return_locked;
}
/* We are already going to do all the verification
* necessary at the socket layer so from our point of
* view it is safe to turn these checks off (and less
* work), however, the CIPSO draft says we should do
* all the CIPSO validations here but it doesn't
* really specify _exactly_ what we need to validate
* ... so, just make it a sysctl tunable. */
if (cipso_v4_rbm_strictvalid) {
if (cipso_v4_map_lvl_valid(doi_def,
tag[3]) < 0) {
err_offset = opt_iter + 3;
goto validate_return_locked;
}
if (tag_len > CIPSO_V4_TAG_RBM_BLEN &&
cipso_v4_map_cat_rbm_valid(doi_def,
&tag[4],
tag_len - 4) < 0) {
err_offset = opt_iter + 4;
goto validate_return_locked;
}
}
break;
case CIPSO_V4_TAG_ENUM:
if (tag_len < CIPSO_V4_TAG_ENUM_BLEN) {
err_offset = opt_iter + 1;
goto validate_return_locked;
}
if (cipso_v4_map_lvl_valid(doi_def,
tag[3]) < 0) {
err_offset = opt_iter + 3;
goto validate_return_locked;
}
if (tag_len > CIPSO_V4_TAG_ENUM_BLEN &&
cipso_v4_map_cat_enum_valid(doi_def,
&tag[4],
tag_len - 4) < 0) {
err_offset = opt_iter + 4;
goto validate_return_locked;
}
break;
case CIPSO_V4_TAG_RANGE:
if (tag_len < CIPSO_V4_TAG_RNG_BLEN) {
err_offset = opt_iter + 1;
goto validate_return_locked;
}
if (cipso_v4_map_lvl_valid(doi_def,
tag[3]) < 0) {
err_offset = opt_iter + 3;
goto validate_return_locked;
}
if (tag_len > CIPSO_V4_TAG_RNG_BLEN &&
cipso_v4_map_cat_rng_valid(doi_def,
&tag[4],
tag_len - 4) < 0) {
err_offset = opt_iter + 4;
goto validate_return_locked;
}
break;
case CIPSO_V4_TAG_LOCAL:
/* This is a non-standard tag that we only allow for
* local connections, so if the incoming interface is
* not the loopback device drop the packet. Further,
* there is no legitimate reason for setting this from
* userspace so reject it if skb is NULL. */
if (skb == NULL || !(skb->dev->flags & IFF_LOOPBACK)) {
err_offset = opt_iter;
goto validate_return_locked;
}
if (tag_len != CIPSO_V4_TAG_LOC_BLEN) {
err_offset = opt_iter + 1;
goto validate_return_locked;
}
break;
default:
err_offset = opt_iter;
goto validate_return_locked;
}
tag += tag_len;
opt_iter += tag_len;
}
validate_return_locked:
rcu_read_unlock();
validate_return:
*option = opt + err_offset;
return err_offset;
}
/**
* cipso_v4_error - Send the correct response for a bad packet
* @skb: the packet
* @error: the error code
* @gateway: CIPSO gateway flag
*
* Description:
* Based on the error code given in @error, send an ICMP error message back to
* the originating host. From the IETF draft ...
*
* "If the contents of the CIPSO [option] are valid but the security label is
* outside of the configured host or port label range, the datagram is
* discarded and an ICMP 'destination unreachable' (type 3) is generated and
* returned. The code field of the ICMP is set to 'communication with
* destination network administratively prohibited' (code 9) or to
* 'communication with destination host administratively prohibited'
* (code 10). The value of the code is dependent on whether the originator
* of the ICMP message is acting as a CIPSO host or a CIPSO gateway. The
* recipient of the ICMP message MUST be able to handle either value. The
* same procedure is performed if a CIPSO [option] can not be added to an
* IP packet because it is too large to fit in the IP options area."
*
* "If the error is triggered by receipt of an ICMP message, the message is
* discarded and no response is permitted (consistent with general ICMP
* processing rules)."
*
*/
void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
{
if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
return;
if (gateway)
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
else
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
}
/**
* cipso_v4_genopt - Generate a CIPSO option
* @buf: the option buffer
* @buf_len: the size of opt_buf
* @doi_def: the CIPSO DOI to use
* @secattr: the security attributes
*
* Description:
* Generate a CIPSO option using the DOI definition and security attributes
* passed to the function. Returns the length of the option on success and
* negative values on failure.
*
*/
static int cipso_v4_genopt(unsigned char *buf, u32 buf_len,
const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val;
u32 iter;
if (buf_len <= CIPSO_V4_HDR_LEN)
return -ENOSPC;
/* XXX - This code assumes only one tag per CIPSO option which isn't
* really a good assumption to make but since we only support the MAC
* tags right now it is a safe assumption. */
iter = 0;
do {
memset(buf, 0, buf_len);
switch (doi_def->tags[iter]) {
case CIPSO_V4_TAG_RBITMAP:
ret_val = cipso_v4_gentag_rbm(doi_def,
secattr,
&buf[CIPSO_V4_HDR_LEN],
buf_len - CIPSO_V4_HDR_LEN);
break;
case CIPSO_V4_TAG_ENUM:
ret_val = cipso_v4_gentag_enum(doi_def,
secattr,
&buf[CIPSO_V4_HDR_LEN],
buf_len - CIPSO_V4_HDR_LEN);
break;
case CIPSO_V4_TAG_RANGE:
ret_val = cipso_v4_gentag_rng(doi_def,
secattr,
&buf[CIPSO_V4_HDR_LEN],
buf_len - CIPSO_V4_HDR_LEN);
break;
case CIPSO_V4_TAG_LOCAL:
ret_val = cipso_v4_gentag_loc(doi_def,
secattr,
&buf[CIPSO_V4_HDR_LEN],
buf_len - CIPSO_V4_HDR_LEN);
break;
default:
return -EPERM;
}
iter++;
} while (ret_val < 0 &&
iter < CIPSO_V4_TAG_MAXCNT &&
doi_def->tags[iter] != CIPSO_V4_TAG_INVALID);
if (ret_val < 0)
return ret_val;
cipso_v4_gentag_hdr(doi_def, buf, ret_val);
return CIPSO_V4_HDR_LEN + ret_val;
}
/**
* cipso_v4_sock_setattr - Add a CIPSO option to a socket
* @sk: the socket
* @doi_def: the CIPSO DOI to use
* @secattr: the specific security attributes of the socket
*
* Description:
* Set the CIPSO option on the given socket using the DOI definition and
* security attributes passed to the function. This function requires
* exclusive access to @sk, which means it either needs to be in the
* process of being created or locked. Returns zero on success and negative
* values on failure.
*
*/
int cipso_v4_sock_setattr(struct sock *sk,
const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val = -EPERM;
unsigned char *buf = NULL;
u32 buf_len;
u32 opt_len;
struct ip_options_rcu *old, *opt = NULL;
struct inet_sock *sk_inet;
struct inet_connection_sock *sk_conn;
/* In the case of sock_create_lite(), the sock->sk field is not
* defined yet but it is not a problem as the only users of these
* "lite" PF_INET sockets are functions which do an accept() call
* afterwards so we will label the socket as part of the accept(). */
if (sk == 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;
}
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 == NULL) {
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, sock_owned_by_user(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 == NULL) {
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 == NULL) {
ret_val = -ENOMEM;
goto req_setattr_failure;
}
memcpy(opt->opt.__data, buf, buf_len);
opt->opt.optlen = opt_len;
opt->opt.cipso = sizeof(struct iphdr);
kfree(buf);
buf = NULL;
req_inet = inet_rsk(req);
opt = xchg(&req_inet->opt, opt);
if (opt)
kfree_rcu(opt, rcu);
return 0;
req_setattr_failure:
kfree(buf);
kfree(opt);
return ret_val;
}
/**
* cipso_v4_delopt - Delete the CIPSO option from a set of IP options
* @opt_ptr: IP option pointer
*
* Description:
* Deletes the CIPSO IP option from a set of IP options and makes the necessary
* adjustments to the IP option structure. Returns zero on success, negative
* values on failure.
*
*/
static int cipso_v4_delopt(struct ip_options_rcu **opt_ptr)
{
int hdr_delta = 0;
struct ip_options_rcu *opt = *opt_ptr;
if (opt->opt.srr || opt->opt.rr || opt->opt.ts || opt->opt.router_alert) {
u8 cipso_len;
u8 cipso_off;
unsigned char *cipso_ptr;
int iter;
int optlen_new;
cipso_off = opt->opt.cipso - sizeof(struct iphdr);
cipso_ptr = &opt->opt.__data[cipso_off];
cipso_len = cipso_ptr[1];
if (opt->opt.srr > opt->opt.cipso)
opt->opt.srr -= cipso_len;
if (opt->opt.rr > opt->opt.cipso)
opt->opt.rr -= cipso_len;
if (opt->opt.ts > opt->opt.cipso)
opt->opt.ts -= cipso_len;
if (opt->opt.router_alert > opt->opt.cipso)
opt->opt.router_alert -= cipso_len;
opt->opt.cipso = 0;
memmove(cipso_ptr, cipso_ptr + cipso_len,
opt->opt.optlen - cipso_off - cipso_len);
/* determining the new total option length is tricky because of
* the padding necessary, the only thing i can think to do at
* this point is walk the options one-by-one, skipping the
* padding at the end to determine the actual option size and
* from there we can determine the new total option length */
iter = 0;
optlen_new = 0;
while (iter < opt->opt.optlen)
if (opt->opt.__data[iter] != IPOPT_NOP) {
iter += opt->opt.__data[iter + 1];
optlen_new = iter;
} else
iter++;
hdr_delta = opt->opt.optlen;
opt->opt.optlen = (optlen_new + 3) & ~3;
hdr_delta -= opt->opt.optlen;
} else {
/* only the cipso option was present on the socket so we can
* remove the entire option struct */
*opt_ptr = NULL;
hdr_delta = opt->opt.optlen;
kfree_rcu(opt, rcu);
}
return hdr_delta;
}
/**
* cipso_v4_sock_delattr - Delete the CIPSO option from a socket
* @sk: the socket
*
* Description:
* Removes the CIPSO option from a socket, if present.
*
*/
void cipso_v4_sock_delattr(struct sock *sk)
{
int hdr_delta;
struct ip_options_rcu *opt;
struct inet_sock *sk_inet;
sk_inet = inet_sk(sk);
opt = rcu_dereference_protected(sk_inet->inet_opt, 1);
if (opt == NULL || opt->opt.cipso == 0)
return;
hdr_delta = cipso_v4_delopt(&sk_inet->inet_opt);
if (sk_inet->is_icsk && hdr_delta > 0) {
struct inet_connection_sock *sk_conn = inet_csk(sk);
sk_conn->icsk_ext_hdr_len -= hdr_delta;
sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
}
}
/**
* cipso_v4_req_delattr - Delete the CIPSO option from a request socket
* @reg: the request socket
*
* Description:
* Removes the CIPSO option from a request socket, if present.
*
*/
void cipso_v4_req_delattr(struct request_sock *req)
{
struct ip_options_rcu *opt;
struct inet_request_sock *req_inet;
req_inet = inet_rsk(req);
opt = req_inet->opt;
if (opt == NULL || opt->opt.cipso == 0)
return;
cipso_v4_delopt(&req_inet->opt);
}
/**
* cipso_v4_getattr - Helper function for the cipso_v4_*_getattr functions
* @cipso: the CIPSO v4 option
* @secattr: the security attributes
*
* Description:
* Inspect @cipso and return the security attributes in @secattr. Returns zero
* on success and negative values on failure.
*
*/
int cipso_v4_getattr(const unsigned char *cipso,
struct netlbl_lsm_secattr *secattr)
{
int ret_val = -ENOMSG;
u32 doi;
struct cipso_v4_doi *doi_def;
if (cipso_v4_cache_check(cipso, cipso[1], secattr) == 0)
return 0;
doi = get_unaligned_be32(&cipso[2]);
rcu_read_lock();
doi_def = cipso_v4_doi_search(doi);
if (doi_def == NULL)
goto getattr_return;
/* XXX - This code assumes only one tag per CIPSO option which isn't
* really a good assumption to make but since we only support the MAC
* tags right now it is a safe assumption. */
switch (cipso[6]) {
case CIPSO_V4_TAG_RBITMAP:
ret_val = cipso_v4_parsetag_rbm(doi_def, &cipso[6], secattr);
break;
case CIPSO_V4_TAG_ENUM:
ret_val = cipso_v4_parsetag_enum(doi_def, &cipso[6], secattr);
break;
case CIPSO_V4_TAG_RANGE:
ret_val = cipso_v4_parsetag_rng(doi_def, &cipso[6], secattr);
break;
case CIPSO_V4_TAG_LOCAL:
ret_val = cipso_v4_parsetag_loc(doi_def, &cipso[6], secattr);
break;
}
if (ret_val == 0)
secattr->type = NETLBL_NLTYPE_CIPSOV4;
getattr_return:
rcu_read_unlock();
return ret_val;
}
/**
* cipso_v4_sock_getattr - Get the security attributes from a sock
* @sk: the sock
* @secattr: the security attributes
*
* Description:
* Query @sk to see if there is a CIPSO option attached to the sock and if
* there is return the CIPSO security attributes in @secattr. This function
* requires that @sk be locked, or privately held, but it does not do any
* locking itself. Returns zero on success and negative values on failure.
*
*/
int cipso_v4_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
{
struct ip_options_rcu *opt;
int res = -ENOMSG;
rcu_read_lock();
opt = rcu_dereference(inet_sk(sk)->inet_opt);
if (opt && opt->opt.cipso)
res = cipso_v4_getattr(opt->opt.__data +
opt->opt.cipso -
sizeof(struct iphdr),
secattr);
rcu_read_unlock();
return res;
}
/**
* cipso_v4_skbuff_setattr - Set the CIPSO option on a packet
* @skb: the packet
* @secattr: the security attributes
*
* Description:
* Set the CIPSO option on the given packet based on the security attributes.
* Returns a pointer to the IP header on success and NULL on failure.
*
*/
int cipso_v4_skbuff_setattr(struct sk_buff *skb,
const struct cipso_v4_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val;
struct iphdr *iph;
struct ip_options *opt = &IPCB(skb)->opt;
unsigned char buf[CIPSO_V4_OPT_LEN_MAX];
u32 buf_len = CIPSO_V4_OPT_LEN_MAX;
u32 opt_len;
int len_delta;
ret_val = cipso_v4_genopt(buf, buf_len, doi_def, secattr);
if (ret_val < 0)
return ret_val;
buf_len = ret_val;
opt_len = (buf_len + 3) & ~3;
/* we overwrite any existing options to ensure that we have enough
* room for the CIPSO option, the reason is that we _need_ to guarantee
* that the security label is applied to the packet - we do the same
* thing when using the socket options and it hasn't caused a problem,
* if we need to we can always revisit this choice later */
len_delta = opt_len - opt->optlen;
/* if we don't ensure enough headroom we could panic on the skb_push()
* call below so make sure we have enough, we are also "mangling" the
* packet so we should probably do a copy-on-write call anyway */
ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
if (ret_val < 0)
return ret_val;
if (len_delta > 0) {
/* we assume that the header + opt->optlen have already been
* "pushed" in ip_options_build() or similar */
iph = ip_hdr(skb);
skb_push(skb, len_delta);
memmove((char *)iph - len_delta, iph, iph->ihl << 2);
skb_reset_network_header(skb);
iph = ip_hdr(skb);
} else if (len_delta < 0) {
iph = ip_hdr(skb);
memset(iph + 1, IPOPT_NOP, opt->optlen);
} else
iph = ip_hdr(skb);
if (opt->optlen > 0)
memset(opt, 0, sizeof(*opt));
opt->optlen = opt_len;
opt->cipso = sizeof(struct iphdr);
opt->is_changed = 1;
/* we have to do the following because we are being called from a
* netfilter hook which means the packet already has had the header
* fields populated and the checksum calculated - yes this means we
* are doing more work than needed but we do it to keep the core
* stack clean and tidy */
memcpy(iph + 1, buf, buf_len);
if (opt_len > buf_len)
memset((char *)(iph + 1) + buf_len, 0, opt_len - buf_len);
if (len_delta != 0) {
iph->ihl = 5 + (opt_len >> 2);
iph->tot_len = htons(skb->len);
}
ip_send_check(iph);
return 0;
}
/**
* cipso_v4_skbuff_delattr - Delete any CIPSO options from a packet
* @skb: the packet
*
* Description:
* Removes any and all CIPSO options from the given packet. Returns zero on
* success, negative values on failure.
*
*/
int cipso_v4_skbuff_delattr(struct sk_buff *skb)
{
int ret_val;
struct iphdr *iph;
struct ip_options *opt = &IPCB(skb)->opt;
unsigned char *cipso_ptr;
if (opt->cipso == 0)
return 0;
/* since we are changing the packet we should make a copy */
ret_val = skb_cow(skb, skb_headroom(skb));
if (ret_val < 0)
return ret_val;
/* the easiest thing to do is just replace the cipso option with noop
* options since we don't change the size of the packet, although we
* still need to recalculate the checksum */
iph = ip_hdr(skb);
cipso_ptr = (unsigned char *)iph + opt->cipso;
memset(cipso_ptr, IPOPT_NOOP, cipso_ptr[1]);
opt->cipso = 0;
opt->is_changed = 1;
ip_send_check(iph);
return 0;
}
/*
* Setup Functions
*/
/**
* cipso_v4_init - Initialize the CIPSO module
*
* Description:
* Initialize the CIPSO module and prepare it for use. Returns zero on success
* and negative values on failure.
*
*/
static int __init cipso_v4_init(void)
{
int ret_val;
ret_val = cipso_v4_cache_init();
if (ret_val != 0)
panic("Failed to initialize the CIPSO/IPv4 cache (%d)\n",
ret_val);
return 0;
}
subsys_initcall(cipso_v4_init);