4 * SELinux must keep a mapping of network ports to labels/SIDs. This
5 * mapping is maintained as part of the normal policy but a fast cache is
6 * needed to reduce the lookup overhead.
8 * Author: Paul Moore <paul.moore@hp.com>
10 * This code is heavily based on the "netif" concept originally developed by
11 * James Morris <jmorris@redhat.com>
12 * (see security/selinux/netif.c for more information)
17 * (c) Copyright Hewlett-Packard Development Company, L.P., 2008
19 * This program is free software: you can redistribute it and/or modify
20 * it under the terms of version 2 of the GNU General Public License as
21 * published by the Free Software Foundation.
23 * This program is distributed in the hope that it will be useful,
24 * but WITHOUT ANY WARRANTY; without even the implied warranty of
25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
26 * GNU General Public License for more details.
30 #include <linux/types.h>
31 #include <linux/rcupdate.h>
32 #include <linux/list.h>
33 #include <linux/slab.h>
34 #include <linux/spinlock.h>
36 #include <linux/in6.h>
38 #include <linux/ipv6.h>
45 #define SEL_NETPORT_HASH_SIZE 256
46 #define SEL_NETPORT_HASH_BKT_LIMIT 16
48 struct sel_netport_bkt {
50 struct list_head list;
54 struct netport_security_struct psec;
56 struct list_head list;
60 /* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
61 * for this is that I suspect most users will not make heavy use of both
62 * address families at the same time so one table will usually end up wasted,
63 * if this becomes a problem we can always add a hash table for each address
66 static LIST_HEAD(sel_netport_list);
67 static DEFINE_SPINLOCK(sel_netport_lock);
68 static struct sel_netport_bkt sel_netport_hash[SEL_NETPORT_HASH_SIZE];
71 * sel_netport_free - Frees a port entry
72 * @p: the entry's RCU field
75 * This function is designed to be used as a callback to the call_rcu()
76 * function so that memory allocated to a hash table port entry can be
80 static void sel_netport_free(struct rcu_head *p)
82 struct sel_netport *port = container_of(p, struct sel_netport, rcu);
87 * sel_netport_hashfn - Hashing function for the port table
91 * This is the hashing function for the port table, it returns the bucket
92 * number for the given port.
95 static unsigned int sel_netport_hashfn(u16 pnum)
97 return (pnum & (SEL_NETPORT_HASH_SIZE - 1));
101 * sel_netport_find - Search for a port record
102 * @protocol: protocol
106 * Search the network port table and return the matching record. If an entry
107 * can not be found in the table return NULL.
110 static struct sel_netport *sel_netport_find(u8 protocol, u16 pnum)
113 struct sel_netport *port;
115 idx = sel_netport_hashfn(pnum);
116 list_for_each_entry_rcu(port, &sel_netport_hash[idx].list, list)
117 if (port->psec.port == pnum && port->psec.protocol == protocol)
124 * sel_netport_insert - Insert a new port into the table
125 * @port: the new port record
128 * Add a new port record to the network address hash table.
131 static void sel_netport_insert(struct sel_netport *port)
135 /* we need to impose a limit on the growth of the hash table so check
136 * this bucket to make sure it is within the specified bounds */
137 idx = sel_netport_hashfn(port->psec.port);
138 list_add_rcu(&port->list, &sel_netport_hash[idx].list);
139 if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) {
140 struct sel_netport *tail;
142 rcu_dereference(sel_netport_hash[idx].list.prev),
143 struct sel_netport, list);
144 list_del_rcu(&tail->list);
145 call_rcu(&tail->rcu, sel_netport_free);
147 sel_netport_hash[idx].size++;
151 * sel_netport_sid_slow - Lookup the SID of a network address using the policy
152 * @protocol: protocol
157 * This function determines the SID of a network port by quering the security
158 * policy. The result is added to the network port table to speedup future
159 * queries. Returns zero on success, negative values on failure.
162 static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
165 struct sel_netport *port;
166 struct sel_netport *new = NULL;
168 spin_lock_bh(&sel_netport_lock);
169 port = sel_netport_find(protocol, pnum);
171 *sid = port->psec.sid;
172 spin_unlock_bh(&sel_netport_lock);
175 new = kzalloc(sizeof(*new), GFP_ATOMIC);
178 ret = security_port_sid(protocol, pnum, sid);
182 new->psec.port = pnum;
183 new->psec.protocol = protocol;
184 new->psec.sid = *sid;
185 sel_netport_insert(new);
188 spin_unlock_bh(&sel_netport_lock);
191 "SELinux: failure in sel_netport_sid_slow(),"
192 " unable to determine network port label\n");
199 * sel_netport_sid - Lookup the SID of a network port
200 * @protocol: protocol
205 * This function determines the SID of a network port using the fastest method
206 * possible. First the port table is queried, but if an entry can't be found
207 * then the policy is queried and the result is added to the table to speedup
208 * future queries. Returns zero on success, negative values on failure.
211 int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid)
213 struct sel_netport *port;
216 port = sel_netport_find(protocol, pnum);
218 *sid = port->psec.sid;
224 return sel_netport_sid_slow(protocol, pnum, sid);
228 * sel_netport_flush - Flush the entire network port table
231 * Remove all entries from the network address table.
234 static void sel_netport_flush(void)
237 struct sel_netport *port, *port_tmp;
239 spin_lock_bh(&sel_netport_lock);
240 for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
241 list_for_each_entry_safe(port, port_tmp,
242 &sel_netport_hash[idx].list, list) {
243 list_del_rcu(&port->list);
244 call_rcu(&port->rcu, sel_netport_free);
246 sel_netport_hash[idx].size = 0;
248 spin_unlock_bh(&sel_netport_lock);
251 static int sel_netport_avc_callback(u32 event, u32 ssid, u32 tsid,
252 u16 class, u32 perms, u32 *retained)
254 if (event == AVC_CALLBACK_RESET) {
261 static __init int sel_netport_init(void)
266 if (!selinux_enabled)
269 for (iter = 0; iter < SEL_NETPORT_HASH_SIZE; iter++) {
270 INIT_LIST_HEAD(&sel_netport_hash[iter].list);
271 sel_netport_hash[iter].size = 0;
274 ret = avc_add_callback(sel_netport_avc_callback, AVC_CALLBACK_RESET,
275 SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
277 panic("avc_add_callback() failed, error %d\n", ret);
282 __initcall(sel_netport_init);