/*
* NetLabel Kernel API
*
* This file defines the kernel API for the NetLabel system. The NetLabel
* system manages static and dynamic label mappings for network protocols such
* as CIPSO and RIPSO.
*
* 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 <net/ip.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <asm/bug.h>
#include <asm/atomic.h>
#include "netlabel_domainhash.h"
#include "netlabel_unlabeled.h"
#include "netlabel_user.h"
#include "netlabel_mgmt.h"
/*
* Security Attribute Functions
*/
/**
* netlbl_secattr_catmap_walk - Walk a LSM secattr catmap looking for a bit
* @catmap: the category bitmap
* @offset: the offset to start searching at, in bits
*
* Description:
* This function walks a LSM secattr category bitmap starting at @offset and
* returns the spot of the first set bit or -ENOENT if no bits are set.
*
*/
int netlbl_secattr_catmap_walk(struct netlbl_lsm_secattr_catmap *catmap,
u32 offset)
{
struct netlbl_lsm_secattr_catmap *iter = catmap;
u32 node_idx;
u32 node_bit;
NETLBL_CATMAP_MAPTYPE bitmap;
if (offset > iter->startbit) {
while (offset >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
iter = iter->next;
if (iter == NULL)
return -ENOENT;
}
node_idx = (offset - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
node_bit = offset - iter->startbit -
(NETLBL_CATMAP_MAPSIZE * node_idx);
} else {
node_idx = 0;
node_bit = 0;
}
bitmap = iter->bitmap[node_idx] >> node_bit;
for (;;) {
if (bitmap != 0) {
while ((bitmap & NETLBL_CATMAP_BIT) == 0) {
bitmap >>= 1;
node_bit++;
}
return iter->startbit +
(NETLBL_CATMAP_MAPSIZE * node_idx) + node_bit;
}
if (++node_idx >= NETLBL_CATMAP_MAPCNT) {
if (iter->next != NULL) {
iter = iter->next;
node_idx = 0;
} else
return -ENOENT;
}
bitmap = iter->bitmap[node_idx];
node_bit = 0;
}
return -ENOENT;
}
/**
* netlbl_secattr_catmap_walk_rng - Find the end of a string of set bits
* @catmap: the category bitmap
* @offset: the offset to start searching at, in bits
*
* Description:
* This function walks a LSM secattr category bitmap starting at @offset and
* returns the spot of the first cleared bit or -ENOENT if the offset is past
* the end of the bitmap.
*
*/
int netlbl_secattr_catmap_walk_rng(struct netlbl_lsm_secattr_catmap *catmap,
u32 offset)
{
struct netlbl_lsm_secattr_catmap *iter = catmap;
u32 node_idx;
u32 node_bit;
NETLBL_CATMAP_MAPTYPE bitmask;
NETLBL_CATMAP_MAPTYPE bitmap;
if (offset > iter->startbit) {
while (offset >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
iter = iter->next;
if (iter == NULL)
return -ENOENT;
}
node_idx = (offset - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
node_bit = offset - iter->startbit -
(NETLBL_CATMAP_MAPSIZE * node_idx);
} else {
node_idx = 0;
node_bit = 0;
}
bitmask = NETLBL_CATMAP_BIT << node_bit;
for (;;) {
bitmap = iter->bitmap[node_idx];
while (bitmask != 0 && (bitmap & bitmask) != 0) {
bitmask <<= 1;
node_bit++;
}
if (bitmask != 0)
return iter->startbit +
(NETLBL_CATMAP_MAPSIZE * node_idx) +
node_bit - 1;
else if (++node_idx >= NETLBL_CATMAP_MAPCNT) {
if (iter->next == NULL)
return iter->startbit + NETLBL_CATMAP_SIZE - 1;
iter = iter->next;
node_idx = 0;
}
bitmask = NETLBL_CATMAP_BIT;
node_bit = 0;
}
return -ENOENT;
}
/**
* netlbl_secattr_catmap_setbit - Set a bit in a LSM secattr catmap
* @catmap: the category bitmap
* @bit: the bit to set
* @flags: memory allocation flags
*
* Description:
* Set the bit specified by @bit in @catmap. Returns zero on success,
* negative values on failure.
*
*/
int netlbl_secattr_catmap_setbit(struct netlbl_lsm_secattr_catmap *catmap,
u32 bit,
gfp_t flags)
{
struct netlbl_lsm_secattr_catmap *iter = catmap;
u32 node_bit;
u32 node_idx;
while (iter->next != NULL &&
bit >= (iter->startbit + NETLBL_CATMAP_SIZE))
iter = iter->next;
if (bit >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
iter->next = netlbl_secattr_catmap_alloc(flags);
if (iter->next == NULL)
return -ENOMEM;
iter = iter->next;
iter->startbit = bit & ~(NETLBL_CATMAP_SIZE - 1);
}
/* gcc always rounds to zero when doing integer division */
node_idx = (bit - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
node_bit = bit - iter->startbit - (NETLBL_CATMAP_MAPSIZE * node_idx);
iter->bitmap[node_idx] |= NETLBL_CATMAP_BIT << node_bit;
return 0;
}
/**
* netlbl_secattr_catmap_setrng - Set a range of bits in a LSM secattr catmap
* @catmap: the category bitmap
* @start: the starting bit
* @end: the last bit in the string
* @flags: memory allocation flags
*
* Description:
* Set a range of bits, starting at @start and ending with @end. Returns zero
* on success, negative values on failure.
*
*/
int netlbl_secattr_catmap_setrng(struct netlbl_lsm_secattr_catmap *catmap,
u32 start,
u32 end,
gfp_t flags)
{
int ret_val = 0;
struct netlbl_lsm_secattr_catmap *iter = catmap;
u32 iter_max_spot;
u32 spot;
/* XXX - This could probably be made a bit faster by combining writes
* to the catmap instead of setting a single bit each time, but for
* right now skipping to the start of the range in the catmap should
* be a nice improvement over calling the individual setbit function
* repeatedly from a loop. */
while (iter->next != NULL &&
start >= (iter->startbit + NETLBL_CATMAP_SIZE))
iter = iter->next;
iter_max_spot = iter->startbit + NETLBL_CATMAP_SIZE;
for (spot = start; spot <= end && ret_val == 0; spot++) {
if (spot >= iter_max_spot && iter->next != NULL) {
iter = iter->next;
iter_max_spot = iter->startbit + NETLBL_CATMAP_SIZE;
}
ret_val = netlbl_secattr_catmap_setbit(iter, spot, GFP_ATOMIC);
}
return ret_val;
}
/*
* LSM Functions
*/
/**
* netlbl_enabled - Determine if the NetLabel subsystem is enabled
*
* Description:
* The LSM can use this function to determine if it should use NetLabel
* security attributes in it's enforcement mechanism. Currently, NetLabel is
* considered to be enabled when it's configuration contains a valid setup for
* at least one labeled protocol (i.e. NetLabel can understand incoming
* labeled packets of at least one type); otherwise NetLabel is considered to
* be disabled.
*
*/
int netlbl_enabled(void)
{
/* At some point we probably want to expose this mechanism to the user
* as well so that admins can toggle NetLabel regardless of the
* configuration */
return (atomic_read(&netlabel_mgmt_protocount) > 0);
}
/**
* netlbl_socket_setattr - Label a socket using the correct protocol
* @sk: the socket to label
* @secattr: the security attributes
*
* Description:
* Attach the correct label to the given socket using the security attributes
* specified in @secattr. 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, negative values on failure.
*
*/
int netlbl_sock_setattr(struct sock *sk,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val = -ENOENT;
struct netlbl_dom_map *dom_entry;
rcu_read_lock();
dom_entry = netlbl_domhsh_getentry(secattr->domain);
if (dom_entry == NULL)
goto socket_setattr_return;
switch (dom_entry->type) {
case NETLBL_NLTYPE_CIPSOV4:
ret_val = cipso_v4_sock_setattr(sk,
dom_entry->type_def.cipsov4,
secattr);
break;
case NETLBL_NLTYPE_UNLABELED:
ret_val = 0;
break;
default:
ret_val = -ENOENT;
}
socket_setattr_return:
rcu_read_unlock();
return ret_val;
}
/**
* netlbl_sock_getattr - Determine the security attributes of a sock
* @sk: the sock
* @secattr: the security attributes
*
* Description:
* Examines the given sock to see any NetLabel style labeling has been
* applied to the sock, if so it parses the socket label and returns the
* security attributes in @secattr. Returns zero on success, negative values
* on failure.
*
*/
int netlbl_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
{
int ret_val;
ret_val = cipso_v4_sock_getattr(sk, secattr);
if (ret_val == 0)
return 0;
return netlbl_unlabel_getattr(secattr);
}
/**
* netlbl_skbuff_getattr - Determine the security attributes of a packet
* @skb: the packet
* @secattr: the security attributes
*
* Description:
* Examines the given packet to see if a recognized form of packet labeling
* is present, if so it parses the packet label and returns the security
* attributes in @secattr. Returns zero on success, negative values on
* failure.
*
*/
int netlbl_skbuff_getattr(const struct sk_buff *skb,
struct netlbl_lsm_secattr *secattr)
{
if (CIPSO_V4_OPTEXIST(skb) &&
cipso_v4_skbuff_getattr(skb, secattr) == 0)
return 0;
return netlbl_unlabel_getattr(secattr);
}
/**
* netlbl_skbuff_err - Handle a LSM error on a sk_buff
* @skb: the packet
* @error: the error code
*
* Description:
* Deal with a LSM problem when handling the packet in @skb, typically this is
* a permission denied problem (-EACCES). The correct action is determined
* according to the packet's labeling protocol.
*
*/
void netlbl_skbuff_err(struct sk_buff *skb, int error)
{
if (CIPSO_V4_OPTEXIST(skb))
cipso_v4_error(skb, error, 0);
}
/**
* netlbl_cache_invalidate - Invalidate all of the NetLabel protocol caches
*
* Description:
* For all of the NetLabel protocols that support some form of label mapping
* cache, invalidate the cache. Returns zero on success, negative values on
* error.
*
*/
void netlbl_cache_invalidate(void)
{
cipso_v4_cache_invalidate();
}
/**
* netlbl_cache_add - Add an entry to a NetLabel protocol cache
* @skb: the packet
* @secattr: the packet's security attributes
*
* Description:
* Add the LSM security attributes for the given packet to the underlying
* NetLabel protocol's label mapping cache. Returns zero on success, negative
* values on error.
*
*/
int netlbl_cache_add(const struct sk_buff *skb,
const struct netlbl_lsm_secattr *secattr)
{
if ((secattr->flags & NETLBL_SECATTR_CACHE) == 0)
return -ENOMSG;
if (CIPSO_V4_OPTEXIST(skb))
return cipso_v4_cache_add(skb, secattr);
return -ENOMSG;
}
/*
* Setup Functions
*/
/**
* netlbl_init - Initialize NetLabel
*
* Description:
* Perform the required NetLabel initialization before first use.
*
*/
static int __init netlbl_init(void)
{
int ret_val;
printk(KERN_INFO "NetLabel: Initializing\n");
printk(KERN_INFO "NetLabel: domain hash size = %u\n",
(1 << NETLBL_DOMHSH_BITSIZE));
printk(KERN_INFO "NetLabel: protocols ="
" UNLABELED"
" CIPSOv4"
"\n");
ret_val = netlbl_domhsh_init(NETLBL_DOMHSH_BITSIZE);
if (ret_val != 0)
goto init_failure;
ret_val = netlbl_netlink_init();
if (ret_val != 0)
goto init_failure;
ret_val = netlbl_unlabel_defconf();
if (ret_val != 0)
goto init_failure;
printk(KERN_INFO "NetLabel: unlabeled traffic allowed by default\n");
return 0;
init_failure:
panic("NetLabel: failed to initialize properly (%d)\n", ret_val);
}
subsys_initcall(netlbl_init);
