linux-stable/security/selinux/netport.c
Paul Moore e9fd729293 selinux: fix all of the W=1 build warnings
There were a number of places in the code where the function
definition did not match the associated comment block as well
at least one file where the appropriate header files were not
included (missing function declaration/prototype); this patch
fixes all of these issue such that building the SELinux code
with "W=1" is now warning free.

 % make W=1 security/selinux/

Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-13 16:31:51 -04:00

238 lines
5.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Network port table
*
* SELinux must keep a mapping of network ports to labels/SIDs. This
* mapping is maintained as part of the normal policy but a fast cache is
* needed to reduce the lookup overhead.
*
* Author: Paul Moore <paul@paul-moore.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., 2008
*/
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/slab.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 "netport.h"
#include "objsec.h"
#define SEL_NETPORT_HASH_SIZE 256
#define SEL_NETPORT_HASH_BKT_LIMIT 16
struct sel_netport_bkt {
int size;
struct list_head list;
};
struct sel_netport {
struct netport_security_struct psec;
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 DEFINE_SPINLOCK(sel_netport_lock);
static struct sel_netport_bkt sel_netport_hash[SEL_NETPORT_HASH_SIZE];
/**
* sel_netport_hashfn - Hashing function for the port table
* @pnum: port number
*
* Description:
* This is the hashing function for the port table, it returns the bucket
* number for the given port.
*
*/
static unsigned int sel_netport_hashfn(u16 pnum)
{
return (pnum & (SEL_NETPORT_HASH_SIZE - 1));
}
/**
* sel_netport_find - Search for a port record
* @protocol: protocol
* @pnum: port
*
* Description:
* Search the network port table and return the matching record. If an entry
* can not be found in the table return NULL.
*
*/
static struct sel_netport *sel_netport_find(u8 protocol, u16 pnum)
{
unsigned int idx;
struct sel_netport *port;
idx = sel_netport_hashfn(pnum);
list_for_each_entry_rcu(port, &sel_netport_hash[idx].list, list)
if (port->psec.port == pnum && port->psec.protocol == protocol)
return port;
return NULL;
}
/**
* sel_netport_insert - Insert a new port into the table
* @port: the new port record
*
* Description:
* Add a new port record to the network address hash table.
*
*/
static void sel_netport_insert(struct sel_netport *port)
{
unsigned int idx;
/* 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 */
idx = sel_netport_hashfn(port->psec.port);
list_add_rcu(&port->list, &sel_netport_hash[idx].list);
if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) {
struct sel_netport *tail;
tail = list_entry(
rcu_dereference_protected(
sel_netport_hash[idx].list.prev,
lockdep_is_held(&sel_netport_lock)),
struct sel_netport, list);
list_del_rcu(&tail->list);
kfree_rcu(tail, rcu);
} else
sel_netport_hash[idx].size++;
}
/**
* sel_netport_sid_slow - Lookup the SID of a network address using the policy
* @protocol: protocol
* @pnum: port
* @sid: port SID
*
* Description:
* This function determines the SID of a network port by querying the security
* policy. The result is added to the network port table to speedup future
* queries. Returns zero on success, negative values on failure.
*
*/
static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
{
int ret;
struct sel_netport *port;
struct sel_netport *new;
spin_lock_bh(&sel_netport_lock);
port = sel_netport_find(protocol, pnum);
if (port != NULL) {
*sid = port->psec.sid;
spin_unlock_bh(&sel_netport_lock);
return 0;
}
ret = security_port_sid(&selinux_state, protocol, pnum, sid);
if (ret != 0)
goto out;
new = kzalloc(sizeof(*new), GFP_ATOMIC);
if (new) {
new->psec.port = pnum;
new->psec.protocol = protocol;
new->psec.sid = *sid;
sel_netport_insert(new);
}
out:
spin_unlock_bh(&sel_netport_lock);
if (unlikely(ret))
pr_warn("SELinux: failure in %s(), unable to determine network port label\n",
__func__);
return ret;
}
/**
* sel_netport_sid - Lookup the SID of a network port
* @protocol: protocol
* @pnum: port
* @sid: port SID
*
* Description:
* This function determines the SID of a network port using the fastest method
* possible. First the port 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_netport_sid(u8 protocol, u16 pnum, u32 *sid)
{
struct sel_netport *port;
rcu_read_lock();
port = sel_netport_find(protocol, pnum);
if (port != NULL) {
*sid = port->psec.sid;
rcu_read_unlock();
return 0;
}
rcu_read_unlock();
return sel_netport_sid_slow(protocol, pnum, sid);
}
/**
* sel_netport_flush - Flush the entire network port table
*
* Description:
* Remove all entries from the network address table.
*
*/
void sel_netport_flush(void)
{
unsigned int idx;
struct sel_netport *port, *port_tmp;
spin_lock_bh(&sel_netport_lock);
for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
list_for_each_entry_safe(port, port_tmp,
&sel_netport_hash[idx].list, list) {
list_del_rcu(&port->list);
kfree_rcu(port, rcu);
}
sel_netport_hash[idx].size = 0;
}
spin_unlock_bh(&sel_netport_lock);
}
static __init int sel_netport_init(void)
{
int iter;
if (!selinux_enabled_boot)
return 0;
for (iter = 0; iter < SEL_NETPORT_HASH_SIZE; iter++) {
INIT_LIST_HEAD(&sel_netport_hash[iter].list);
sel_netport_hash[iter].size = 0;
}
return 0;
}
__initcall(sel_netport_init);