348 lines
8.7 KiB
C
348 lines
8.7 KiB
C
|
/*
|
||
|
|
* Network node table
|
||
|
|
*
|
||
|
|
* SELinux must keep a mapping of network nodes to labels/SIDs. This
|
||
|
|
* mapping is maintained as part of the normal policy but a fast cache is
|
||
|
|
* needed to reduce the lookup overhead since most of these queries happen on
|
||
|
|
* a per-packet basis.
|
||
|
|
*
|
||
|
|
* Author: Paul Moore <paul.moore@hp.com>
|
||
|
|
*
|
||
|
|
* This code is heavily based on the "netif" concept originally developed by
|
||
|
|
* James Morris <jmorris@redhat.com>
|
||
|
|
* (see security/selinux/netif.c for more information)
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* (c) Copyright Hewlett-Packard Development Company, L.P., 2007
|
||
|
|
*
|
||
|
|
* This program is free software: you can redistribute it and/or modify
|
||
|
|
* it under the terms of version 2 of the GNU General Public License as
|
||
|
|
* published by the Free Software Foundation.
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/types.h>
|
||
|
|
#include <linux/rcupdate.h>
|
||
|
|
#include <linux/list.h>
|
||
|
|
#include <linux/spinlock.h>
|
||
|
|
#include <linux/in.h>
|
||
|
|
#include <linux/in6.h>
|
||
|
|
#include <linux/ip.h>
|
||
|
|
#include <linux/ipv6.h>
|
||
|
|
#include <net/ip.h>
|
||
|
|
#include <net/ipv6.h>
|
||
|
|
|
||
|
|
#include "netnode.h"
|
||
|
|
#include "objsec.h"
|
||
|
|
|
||
|
|
#define SEL_NETNODE_HASH_SIZE 256
|
||
|
|
#define SEL_NETNODE_HASH_BKT_LIMIT 16
|
||
|
|
|
||
|
|
struct sel_netnode_bkt {
|
||
|
|
unsigned int size;
|
||
|
|
struct list_head list;
|
||
|
|
};
|
||
|
|
|
||
|
|
struct sel_netnode {
|
||
|
|
struct netnode_security_struct nsec;
|
||
|
|
|
||
|
|
struct list_head list;
|
||
|
|
struct rcu_head rcu;
|
||
|
|
};
|
||
|
|
|
||
|
|
/* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
|
||
|
|
* for this is that I suspect most users will not make heavy use of both
|
||
|
|
* address families at the same time so one table will usually end up wasted,
|
||
|
|
* if this becomes a problem we can always add a hash table for each address
|
||
|
|
* family later */
|
||
|
|
|
||
|
|
static LIST_HEAD(sel_netnode_list);
|
||
|
|
static DEFINE_SPINLOCK(sel_netnode_lock);
|
||
|
|
static struct sel_netnode_bkt sel_netnode_hash[SEL_NETNODE_HASH_SIZE];
|
||
|
|
|
||
|
|
/**
|
||
|
|
* sel_netnode_free - Frees a node entry
|
||
|
|
* @p: the entry's RCU field
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* This function is designed to be used as a callback to the call_rcu()
|
||
|
|
* function so that memory allocated to a hash table node entry can be
|
||
|
|
* released safely.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
static void sel_netnode_free(struct rcu_head *p)
|
||
|
|
{
|
||
|
|
struct sel_netnode *node = container_of(p, struct sel_netnode, rcu);
|
||
|
|
kfree(node);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* sel_netnode_hashfn_ipv4 - IPv4 hashing function for the node table
|
||
|
|
* @addr: IPv4 address
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* This is the IPv4 hashing function for the node interface table, it returns
|
||
|
|
* the bucket number for the given IP address.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
static unsigned int sel_netnode_hashfn_ipv4(__be32 addr)
|
||
|
|
{
|
||
|
|
/* at some point we should determine if the mismatch in byte order
|
||
|
|
* affects the hash function dramatically */
|
||
|
|
return (addr & (SEL_NETNODE_HASH_SIZE - 1));
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* sel_netnode_hashfn_ipv6 - IPv6 hashing function for the node table
|
||
|
|
* @addr: IPv6 address
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* This is the IPv6 hashing function for the node interface table, it returns
|
||
|
|
* the bucket number for the given IP address.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
static unsigned int sel_netnode_hashfn_ipv6(const struct in6_addr *addr)
|
||
|
|
{
|
||
|
|
/* just hash the least significant 32 bits to keep things fast (they
|
||
|
|
* are the most likely to be different anyway), we can revisit this
|
||
|
|
* later if needed */
|
||
|
|
return (addr->s6_addr32[3] & (SEL_NETNODE_HASH_SIZE - 1));
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* sel_netnode_find - Search for a node record
|
||
|
|
* @addr: IP address
|
||
|
|
* @family: address family
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* Search the network node table and return the record matching @addr. If an
|
||
|
|
* entry can not be found in the table return NULL.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
static struct sel_netnode *sel_netnode_find(const void *addr, u16 family)
|
||
|
|
{
|
||
|
|
unsigned int idx;
|
||
|
|
struct sel_netnode *node;
|
||
|
|
|
||
|
|
switch (family) {
|
||
|
|
case PF_INET:
|
||
|
|
idx = sel_netnode_hashfn_ipv4(*(__be32 *)addr);
|
||
|
|
break;
|
||
|
|
case PF_INET6:
|
||
|
|
idx = sel_netnode_hashfn_ipv6(addr);
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
BUG();
|
||
|
|
}
|
||
|
|
|
||
|
|
list_for_each_entry_rcu(node, &sel_netnode_hash[idx].list, list)
|
||
|
|
if (node->nsec.family == family)
|
||
|
|
switch (family) {
|
||
|
|
case PF_INET:
|
||
|
|
if (node->nsec.addr.ipv4 == *(__be32 *)addr)
|
||
|
|
return node;
|
||
|
|
break;
|
||
|
|
case PF_INET6:
|
||
|
|
if (ipv6_addr_equal(&node->nsec.addr.ipv6,
|
||
|
|
addr))
|
||
|
|
return node;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* sel_netnode_insert - Insert a new node into the table
|
||
|
|
* @node: the new node record
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* Add a new node record to the network address hash table.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
static void sel_netnode_insert(struct sel_netnode *node)
|
||
|
|
{
|
||
|
|
unsigned int idx;
|
||
|
|
|
||
|
|
switch (node->nsec.family) {
|
||
|
|
case PF_INET:
|
||
|
|
idx = sel_netnode_hashfn_ipv4(node->nsec.addr.ipv4);
|
||
|
|
break;
|
||
|
|
case PF_INET6:
|
||
|
|
idx = sel_netnode_hashfn_ipv6(&node->nsec.addr.ipv6);
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
BUG();
|
||
|
|
}
|
||
|
|
|
||
|
|
INIT_RCU_HEAD(&node->rcu);
|
||
|
|
|
||
|
|
/* we need to impose a limit on the growth of the hash table so check
|
||
|
|
* this bucket to make sure it is within the specified bounds */
|
||
|
|
list_add_rcu(&node->list, &sel_netnode_hash[idx].list);
|
||
|
|
if (sel_netnode_hash[idx].size == SEL_NETNODE_HASH_BKT_LIMIT) {
|
||
|
|
struct sel_netnode *tail;
|
||
|
|
tail = list_entry(
|
||
|
|
rcu_dereference(sel_netnode_hash[idx].list.prev),
|
||
|
|
struct sel_netnode, list);
|
||
|
|
list_del_rcu(&tail->list);
|
||
|
|
call_rcu(&tail->rcu, sel_netnode_free);
|
||
|
|
} else
|
||
|
|
sel_netnode_hash[idx].size++;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* sel_netnode_sid_slow - Lookup the SID of a network address using the policy
|
||
|
|
* @addr: the IP address
|
||
|
|
* @family: the address family
|
||
|
|
* @sid: node SID
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* This function determines the SID of a network address by quering the
|
||
|
|
* security policy. The result is added to the network address table to
|
||
|
|
* speedup future queries. Returns zero on success, negative values on
|
||
|
|
* failure.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid)
|
||
|
|
{
|
||
|
|
int ret = -ENOMEM;
|
||
|
|
struct sel_netnode *node;
|
||
|
|
struct sel_netnode *new = NULL;
|
||
|
|
|
||
|
|
spin_lock_bh(&sel_netnode_lock);
|
||
|
|
node = sel_netnode_find(addr, family);
|
||
|
|
if (node != NULL) {
|
||
|
|
*sid = node->nsec.sid;
|
||
|
|
spin_unlock_bh(&sel_netnode_lock);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
new = kzalloc(sizeof(*new), GFP_ATOMIC);
|
||
|
|
if (new == NULL)
|
||
|
|
goto out;
|
||
|
|
switch (family) {
|
||
|
|
case PF_INET:
|
||
|
|
ret = security_node_sid(PF_INET,
|
||
|
|
addr, sizeof(struct in_addr), sid);
|
||
|
|
new->nsec.addr.ipv4 = *(__be32 *)addr;
|
||
|
|
break;
|
||
|
|
case PF_INET6:
|
||
|
|
ret = security_node_sid(PF_INET6,
|
||
|
|
addr, sizeof(struct in6_addr), sid);
|
||
|
|
ipv6_addr_copy(&new->nsec.addr.ipv6, addr);
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
BUG();
|
||
|
|
}
|
||
|
|
if (ret != 0)
|
||
|
|
goto out;
|
||
|
|
|
||
|
|
new->nsec.family = family;
|
||
|
|
new->nsec.sid = *sid;
|
||
|
|
sel_netnode_insert(new);
|
||
|
|
|
||
|
|
out:
|
||
|
|
spin_unlock_bh(&sel_netnode_lock);
|
||
|
|
if (unlikely(ret)) {
|
||
|
|
printk(KERN_WARNING
|
||
|
|
"SELinux: failure in sel_netnode_sid_slow(),"
|
||
|
|
" unable to determine network node label\n");
|
||
|
|
kfree(new);
|
||
|
|
}
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* sel_netnode_sid - Lookup the SID of a network address
|
||
|
|
* @addr: the IP address
|
||
|
|
* @family: the address family
|
||
|
|
* @sid: node SID
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* This function determines the SID of a network address using the fastest
|
||
|
|
* method possible. First the address table is queried, but if an entry
|
||
|
|
* can't be found then the policy is queried and the result is added to the
|
||
|
|
* table to speedup future queries. Returns zero on success, negative values
|
||
|
|
* on failure.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
int sel_netnode_sid(void *addr, u16 family, u32 *sid)
|
||
|
|
{
|
||
|
|
struct sel_netnode *node;
|
||
|
|
|
||
|
|
rcu_read_lock();
|
||
|
|
node = sel_netnode_find(addr, family);
|
||
|
|
if (node != NULL) {
|
||
|
|
*sid = node->nsec.sid;
|
||
|
|
rcu_read_unlock();
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
rcu_read_unlock();
|
||
|
|
|
||
|
|
return sel_netnode_sid_slow(addr, family, sid);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* sel_netnode_flush - Flush the entire network address table
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* Remove all entries from the network address table.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
static void sel_netnode_flush(void)
|
||
|
|
{
|
||
|
|
unsigned int idx;
|
||
|
|
struct sel_netnode *node, *node_tmp;
|
||
|
|
|
||
|
|
spin_lock_bh(&sel_netnode_lock);
|
||
|
|
for (idx = 0; idx < SEL_NETNODE_HASH_SIZE; idx++) {
|
||
|
|
list_for_each_entry_safe(node, node_tmp,
|
||
|
|
&sel_netnode_hash[idx].list, list) {
|
||
|
|
list_del_rcu(&node->list);
|
||
|
|
call_rcu(&node->rcu, sel_netnode_free);
|
||
|
|
}
|
||
|
|
sel_netnode_hash[idx].size = 0;
|
||
|
|
}
|
||
|
|
spin_unlock_bh(&sel_netnode_lock);
|
||
|
|
}
|
||
|
|
|
||
|
|
static int sel_netnode_avc_callback(u32 event, u32 ssid, u32 tsid,
|
||
|
|
u16 class, u32 perms, u32 *retained)
|
||
|
|
{
|
||
|
|
if (event == AVC_CALLBACK_RESET) {
|
||
|
|
sel_netnode_flush();
|
||
|
|
synchronize_net();
|
||
|
|
}
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static __init int sel_netnode_init(void)
|
||
|
|
{
|
||
|
|
int iter;
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
if (!selinux_enabled)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
for (iter = 0; iter < SEL_NETNODE_HASH_SIZE; iter++) {
|
||
|
|
INIT_LIST_HEAD(&sel_netnode_hash[iter].list);
|
||
|
|
sel_netnode_hash[iter].size = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = avc_add_callback(sel_netnode_avc_callback, AVC_CALLBACK_RESET,
|
||
|
|
SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
|
||
|
|
if (ret != 0)
|
||
|
|
panic("avc_add_callback() failed, error %d\n", ret);
|
||
|
|
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
__initcall(sel_netnode_init);
|