1// SPDX-License-Identifier: GPL-2.0-only
  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 *
  9 * Author: Paul Moore <paul@paul-moore.com>
 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)
 14 */
 15
 16/*
 17 * (c) Copyright Hewlett-Packard Development Company, L.P., 2008
 18 */
 19
 20#include <linux/types.h>
 21#include <linux/rcupdate.h>
 22#include <linux/list.h>
 23#include <linux/slab.h>
 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>
 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
 38struct sel_netport_bkt {
 39	int size;
 40	struct list_head list;
 41};
 42
 43struct 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
 
 56static DEFINE_SPINLOCK(sel_netport_lock);
 57static struct sel_netport_bkt sel_netport_hash[SEL_NETPORT_HASH_SIZE];
 58
 59/**
 60 * sel_netport_hashfn - Hashing function for the port table
 61 * @pnum: port number
 62 *
 63 * Description:
 64 * This is the hashing function for the port table, it returns the bucket
 65 * number for the given port.
 66 *
 67 */
 68static unsigned int sel_netport_hashfn(u16 pnum)
 69{
 70	return (pnum & (SEL_NETPORT_HASH_SIZE - 1));
 71}
 72
 73/**
 74 * sel_netport_find - Search for a port record
 75 * @protocol: protocol
 76 * @pnum: port
 77 *
 78 * Description:
 79 * Search the network port table and return the matching record.  If an entry
 80 * can not be found in the table return NULL.
 81 *
 82 */
 83static struct sel_netport *sel_netport_find(u8 protocol, u16 pnum)
 84{
 85	unsigned int idx;
 86	struct sel_netport *port;
 87
 88	idx = sel_netport_hashfn(pnum);
 89	list_for_each_entry_rcu(port, &sel_netport_hash[idx].list, list)
 90		if (port->psec.port == pnum && port->psec.protocol == protocol)
 91			return port;
 92
 93	return NULL;
 94}
 95
 96/**
 97 * sel_netport_insert - Insert a new port into the table
 98 * @port: the new port record
 99 *
100 * Description:
101 * Add a new port record to the network address hash table.
102 *
103 */
104static void sel_netport_insert(struct sel_netport *port)
105{
106	unsigned int idx;
107
108	/* we need to impose a limit on the growth of the hash table so check
109	 * this bucket to make sure it is within the specified bounds */
110	idx = sel_netport_hashfn(port->psec.port);
111	list_add_rcu(&port->list, &sel_netport_hash[idx].list);
112	if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) {
113		struct sel_netport *tail;
114		tail = list_entry(
115			rcu_dereference_protected(
116				list_tail_rcu(&sel_netport_hash[idx].list),
117				lockdep_is_held(&sel_netport_lock)),
118			struct sel_netport, list);
119		list_del_rcu(&tail->list);
120		kfree_rcu(tail, rcu);
121	} else
122		sel_netport_hash[idx].size++;
123}
124
125/**
126 * sel_netport_sid_slow - Lookup the SID of a network address using the policy
127 * @protocol: protocol
128 * @pnum: port
129 * @sid: port SID
130 *
131 * Description:
132 * This function determines the SID of a network port by querying the security
133 * policy.  The result is added to the network port table to speedup future
134 * queries.  Returns zero on success, negative values on failure.
135 *
136 */
137static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
138{
139	int ret;
140	struct sel_netport *port;
141	struct sel_netport *new;
142
143	spin_lock_bh(&sel_netport_lock);
144	port = sel_netport_find(protocol, pnum);
145	if (port != NULL) {
146		*sid = port->psec.sid;
147		spin_unlock_bh(&sel_netport_lock);
148		return 0;
149	}
150
151	ret = security_port_sid(&selinux_state, protocol, pnum, sid);
152	if (ret != 0)
153		goto out;
154	new = kzalloc(sizeof(*new), GFP_ATOMIC);
155	if (new) {
156		new->psec.port = pnum;
157		new->psec.protocol = protocol;
158		new->psec.sid = *sid;
159		sel_netport_insert(new);
160	}
161
162out:
163	spin_unlock_bh(&sel_netport_lock);
164	if (unlikely(ret))
165		pr_warn("SELinux: failure in %s(), unable to determine network port label\n",
166			__func__);
167	return ret;
168}
169
170/**
171 * sel_netport_sid - Lookup the SID of a network port
172 * @protocol: protocol
173 * @pnum: port
174 * @sid: port SID
175 *
176 * Description:
177 * This function determines the SID of a network port using the fastest method
178 * possible.  First the port table is queried, but if an entry can't be found
179 * then the policy is queried and the result is added to the table to speedup
180 * future queries.  Returns zero on success, negative values on failure.
181 *
182 */
183int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid)
184{
185	struct sel_netport *port;
186
187	rcu_read_lock();
188	port = sel_netport_find(protocol, pnum);
189	if (port != NULL) {
190		*sid = port->psec.sid;
191		rcu_read_unlock();
192		return 0;
193	}
194	rcu_read_unlock();
195
196	return sel_netport_sid_slow(protocol, pnum, sid);
197}
198
199/**
200 * sel_netport_flush - Flush the entire network port table
201 *
202 * Description:
203 * Remove all entries from the network address table.
204 *
205 */
206void sel_netport_flush(void)
207{
208	unsigned int idx;
209	struct sel_netport *port, *port_tmp;
210
211	spin_lock_bh(&sel_netport_lock);
212	for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
213		list_for_each_entry_safe(port, port_tmp,
214					 &sel_netport_hash[idx].list, list) {
215			list_del_rcu(&port->list);
216			kfree_rcu(port, rcu);
217		}
218		sel_netport_hash[idx].size = 0;
219	}
220	spin_unlock_bh(&sel_netport_lock);
221}
222
223static __init int sel_netport_init(void)
224{
225	int iter;
226
227	if (!selinux_enabled_boot)
228		return 0;
229
230	for (iter = 0; iter < SEL_NETPORT_HASH_SIZE; iter++) {
231		INIT_LIST_HEAD(&sel_netport_hash[iter].list);
232		sel_netport_hash[iter].size = 0;
233	}
234
235	return 0;
236}
237
238__initcall(sel_netport_init);

  1// SPDX-License-Identifier: GPL-2.0-only
  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 *
  9 * Author: Paul Moore <paul@paul-moore.com>
 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)
 14 */
 15
 16/*
 17 * (c) Copyright Hewlett-Packard Development Company, L.P., 2008
 18 */
 19
 20#include <linux/types.h>
 21#include <linux/rcupdate.h>
 22#include <linux/list.h>
 23#include <linux/slab.h>
 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>
 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
 38struct sel_netport_bkt {
 39	int size;
 40	struct list_head list;
 41};
 42
 43struct 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
 56static LIST_HEAD(sel_netport_list);
 57static DEFINE_SPINLOCK(sel_netport_lock);
 58static struct sel_netport_bkt sel_netport_hash[SEL_NETPORT_HASH_SIZE];
 59
 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 */
 69static 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 */
 84static 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)
 91		if (port->psec.port == pnum && port->psec.protocol == protocol)
 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:
102 * Add a new port record to the network address hash table.
103 *
104 */
105static void sel_netport_insert(struct sel_netport *port)
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;
115		tail = list_entry(
116			rcu_dereference_protected(
117				sel_netport_hash[idx].list.prev,
118				lockdep_is_held(&sel_netport_lock)),
119			struct sel_netport, list);
120		list_del_rcu(&tail->list);
121		kfree_rcu(tail, rcu);
122	} else
123		sel_netport_hash[idx].size++;
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 querying 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 */
138static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
139{
140	int ret;
141	struct sel_netport *port;
142	struct sel_netport *new;
143
144	spin_lock_bh(&sel_netport_lock);
145	port = sel_netport_find(protocol, pnum);
146	if (port != NULL) {
147		*sid = port->psec.sid;
148		spin_unlock_bh(&sel_netport_lock);
149		return 0;
150	}
151
152	ret = security_port_sid(&selinux_state, protocol, pnum, sid);
153	if (ret != 0)
154		goto out;
155	new = kzalloc(sizeof(*new), GFP_ATOMIC);
156	if (new) {
157		new->psec.port = pnum;
158		new->psec.protocol = protocol;
159		new->psec.sid = *sid;
160		sel_netport_insert(new);
161	}
162
163out:
164	spin_unlock_bh(&sel_netport_lock);
165	if (unlikely(ret))
166		pr_warn("SELinux: failure in %s(), unable to determine network port label\n",
167			__func__);
168	return ret;
169}
170
171/**
172 * sel_netport_sid - Lookup the SID of a network port
173 * @protocol: protocol
174 * @pnum: port
175 * @sid: port SID
176 *
177 * Description:
178 * This function determines the SID of a network port using the fastest method
179 * possible.  First the port table is queried, but if an entry can't be found
180 * then the policy is queried and the result is added to the table to speedup
181 * future queries.  Returns zero on success, negative values on failure.
182 *
183 */
184int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid)
185{
186	struct sel_netport *port;
187
188	rcu_read_lock();
189	port = sel_netport_find(protocol, pnum);
190	if (port != NULL) {
191		*sid = port->psec.sid;
192		rcu_read_unlock();
193		return 0;
194	}
195	rcu_read_unlock();
196
197	return sel_netport_sid_slow(protocol, pnum, sid);
198}
199
200/**
201 * sel_netport_flush - Flush the entire network port table
202 *
203 * Description:
204 * Remove all entries from the network address table.
205 *
206 */
207void sel_netport_flush(void)
208{
209	unsigned int idx;
210	struct sel_netport *port, *port_tmp;
211
212	spin_lock_bh(&sel_netport_lock);
213	for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
214		list_for_each_entry_safe(port, port_tmp,
215					 &sel_netport_hash[idx].list, list) {
216			list_del_rcu(&port->list);
217			kfree_rcu(port, rcu);
218		}
219		sel_netport_hash[idx].size = 0;
220	}
221	spin_unlock_bh(&sel_netport_lock);
222}
223
224static __init int sel_netport_init(void)
225{
226	int iter;
227
228	if (!selinux_enabled_boot)
229		return 0;
230
231	for (iter = 0; iter < SEL_NETPORT_HASH_SIZE; iter++) {
232		INIT_LIST_HEAD(&sel_netport_hash[iter].list);
233		sel_netport_hash[iter].size = 0;
234	}
235
236	return 0;
237}
238
239__initcall(sel_netport_init);