[mirror_ubuntu-eoan-kernel.git] / security / selinux / netport.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 LIST_HEAD(sel_netport_list);
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
 * @port: pnum
 *
 * 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 quering 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 = -ENOMEM;
	struct sel_netport *port;
	struct sel_netport *new = NULL;

	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;
	}
	new = kzalloc(sizeof(*new), GFP_ATOMIC);
	if (new == NULL)
		goto out;
	ret = security_port_sid(&selinux_state, protocol, pnum, sid);
	if (ret != 0)
		goto out;

	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__);
		kfree(new);
	}
	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)
		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);
Commit	Line	Data
5b497af4	1	// SPDX-License-Identifier: GPL-2.0-only
27cc2a6e JM	2	/*
	3	* Network port table
	4	*
	5	* SELinux must keep a mapping of network ports to labels/SIDs. This
	6	* mapping is maintained as part of the normal policy but a fast cache is
	7	* needed to reduce the lookup overhead.
	8	*
82c21bfa	9	* Author: Paul Moore <paul@paul-moore.com>
27cc2a6e JM	10	*
	11	* This code is heavily based on the "netif" concept originally developed by
	12	* James Morris <jmorris@redhat.com>
	13	* (see security/selinux/netif.c for more information)
27cc2a6e JM	14	*/
	15
	16	/*
	17	* (c) Copyright Hewlett-Packard Development Company, L.P., 2008
27cc2a6e JM	18	*/
	19
	20	#include <linux/types.h>
	21	#include <linux/rcupdate.h>
	22	#include <linux/list.h>
5a0e3ad6	23	#include <linux/slab.h>
27cc2a6e JM	24	#include <linux/spinlock.h>
	25	#include <linux/in.h>
	26	#include <linux/in6.h>
	27	#include <linux/ip.h>
	28	#include <linux/ipv6.h>
	29	#include <net/ip.h>
	30	#include <net/ipv6.h>
27cc2a6e JM	31
	32	#include "netport.h"
	33	#include "objsec.h"
	34
	35	#define SEL_NETPORT_HASH_SIZE 256
	36	#define SEL_NETPORT_HASH_BKT_LIMIT 16
	37
	38	struct sel_netport_bkt {
	39	int size;
	40	struct list_head list;
	41	};
	42
	43	struct sel_netport {
	44	struct netport_security_struct psec;
	45
	46	struct list_head list;
	47	struct rcu_head rcu;
	48	};
	49
	50	/* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
	51	* for this is that I suspect most users will not make heavy use of both
	52	* address families at the same time so one table will usually end up wasted,
	53	* if this becomes a problem we can always add a hash table for each address
	54	* family later */
	55
	56	static LIST_HEAD(sel_netport_list);
	57	static DEFINE_SPINLOCK(sel_netport_lock);
	58	static struct sel_netport_bkt sel_netport_hash[SEL_NETPORT_HASH_SIZE];
	59
27cc2a6e JM	60	/**
	61	* sel_netport_hashfn - Hashing function for the port table
	62	* @pnum: port number
	63	*
	64	* Description:
	65	* This is the hashing function for the port table, it returns the bucket
	66	* number for the given port.
	67	*
	68	*/
	69	static unsigned int sel_netport_hashfn(u16 pnum)
	70	{
	71	return (pnum & (SEL_NETPORT_HASH_SIZE - 1));
	72	}
	73
	74	/**
	75	* sel_netport_find - Search for a port record
	76	* @protocol: protocol
	77	* @port: pnum
	78	*
	79	* Description:
	80	* Search the network port table and return the matching record. If an entry
	81	* can not be found in the table return NULL.
	82	*
	83	*/
	84	static struct sel_netport *sel_netport_find(u8 protocol, u16 pnum)
	85	{
	86	unsigned int idx;
	87	struct sel_netport *port;
	88
	89	idx = sel_netport_hashfn(pnum);
	90	list_for_each_entry_rcu(port, &sel_netport_hash[idx].list, list)
c9b7b979	91	if (port->psec.port == pnum && port->psec.protocol == protocol)
27cc2a6e JM	92	return port;
	93
	94	return NULL;
	95	}
	96
	97	/**
	98	* sel_netport_insert - Insert a new port into the table
	99	* @port: the new port record
	100	*
	101	* Description:
c9b7b979	102	* Add a new port record to the network address hash table.
27cc2a6e JM	103	*
27cc2a6e JM	104	*/
c9b7b979	105	static void sel_netport_insert(struct sel_netport *port)
27cc2a6e JM	106	{
	107	unsigned int idx;
	108
	109	/* we need to impose a limit on the growth of the hash table so check
	110	* this bucket to make sure it is within the specified bounds */
	111	idx = sel_netport_hashfn(port->psec.port);
	112	list_add_rcu(&port->list, &sel_netport_hash[idx].list);
	113	if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) {
	114	struct sel_netport *tail;
c9b7b979	115	tail = list_entry(
50345f1e DH	116	rcu_dereference_protected(
	117	sel_netport_hash[idx].list.prev,
	118	lockdep_is_held(&sel_netport_lock)),
c9b7b979 PM	119	struct sel_netport, list);
c9b7b979 PM	120	list_del_rcu(&tail->list);
449a68cc	121	kfree_rcu(tail, rcu);
27cc2a6e JM	122	} else
27cc2a6e JM	123	sel_netport_hash[idx].size++;
27cc2a6e JM	124	}
	125
	126	/**
	127	* sel_netport_sid_slow - Lookup the SID of a network address using the policy
	128	* @protocol: protocol
	129	* @pnum: port
	130	* @sid: port SID
	131	*
	132	* Description:
	133	* This function determines the SID of a network port by quering the security
	134	* policy. The result is added to the network port table to speedup future
	135	* queries. Returns zero on success, negative values on failure.
	136	*
	137	*/
	138	static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
	139	{
c9b7b979	140	int ret = -ENOMEM;
27cc2a6e JM	141	struct sel_netport *port;
	142	struct sel_netport *new = NULL;
	143
	144	spin_lock_bh(&sel_netport_lock);
	145	port = sel_netport_find(protocol, pnum);
	146	if (port != NULL) {
	147	*sid = port->psec.sid;
c9b7b979 PM	148	spin_unlock_bh(&sel_netport_lock);
c9b7b979 PM	149	return 0;
27cc2a6e JM	150	}
27cc2a6e JM	151	new = kzalloc(sizeof(*new), GFP_ATOMIC);
c9b7b979	152	if (new == NULL)
27cc2a6e	153	goto out;
aa8e712c	154	ret = security_port_sid(&selinux_state, protocol, pnum, sid);
27cc2a6e JM	155	if (ret != 0)
27cc2a6e JM	156	goto out;
c9b7b979	157
27cc2a6e JM	158	new->psec.port = pnum;
27cc2a6e JM	159	new->psec.protocol = protocol;
c9b7b979 PM	160	new->psec.sid = *sid;
c9b7b979 PM	161	sel_netport_insert(new);
27cc2a6e JM	162
	163	out:
	164	spin_unlock_bh(&sel_netport_lock);
	165	if (unlikely(ret)) {
d006469d	166	pr_warn("SELinux: failure in %s(), unable to determine network port label\n",
d006469d	167	__func__);
27cc2a6e JM	168	kfree(new);
	169	}
	170	return ret;
	171	}
	172
	173	/**
	174	* sel_netport_sid - Lookup the SID of a network port
	175	* @protocol: protocol
	176	* @pnum: port
	177	* @sid: port SID
	178	*
	179	* Description:
	180	* This function determines the SID of a network port using the fastest method
	181	* possible. First the port table is queried, but if an entry can't be found
	182	* then the policy is queried and the result is added to the table to speedup
	183	* future queries. Returns zero on success, negative values on failure.
	184	*
	185	*/
	186	int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid)
	187	{
	188	struct sel_netport *port;
	189
	190	rcu_read_lock();
	191	port = sel_netport_find(protocol, pnum);
	192	if (port != NULL) {
	193	*sid = port->psec.sid;
	194	rcu_read_unlock();
	195	return 0;
	196	}
	197	rcu_read_unlock();
	198
	199	return sel_netport_sid_slow(protocol, pnum, sid);
	200	}
	201
	202	/**
	203	* sel_netport_flush - Flush the entire network port table
	204	*
	205	* Description:
	206	* Remove all entries from the network address table.
	207	*
	208	*/
615e51fd	209	void sel_netport_flush(void)
27cc2a6e JM	210	{
27cc2a6e JM	211	unsigned int idx;
c9b7b979	212	struct sel_netport port, port_tmp;
27cc2a6e JM	213
	214	spin_lock_bh(&sel_netport_lock);
	215	for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
c9b7b979 PM	216	list_for_each_entry_safe(port, port_tmp,
c9b7b979 PM	217	&sel_netport_hash[idx].list, list) {
27cc2a6e	218	list_del_rcu(&port->list);
449a68cc	219	kfree_rcu(port, rcu);
27cc2a6e JM	220	}
	221	sel_netport_hash[idx].size = 0;
	222	}
	223	spin_unlock_bh(&sel_netport_lock);
	224	}
	225
27cc2a6e JM	226	static __init int sel_netport_init(void)
	227	{
	228	int iter;
27cc2a6e JM	229
	230	if (!selinux_enabled)
	231	return 0;
	232
	233	for (iter = 0; iter < SEL_NETPORT_HASH_SIZE; iter++) {
	234	INIT_LIST_HEAD(&sel_netport_hash[iter].list);
	235	sel_netport_hash[iter].size = 0;
	236	}
	237
942ba364	238	return 0;
27cc2a6e JM	239	}
	240
	241	__initcall(sel_netport_init);