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@paul-moore.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_hashfn - Hashing function for the port table
75 * This is the hashing function for the port table, it returns the bucket
76 * number for the given port.
79 static unsigned int sel_netport_hashfn(u16 pnum)
81 return (pnum & (SEL_NETPORT_HASH_SIZE - 1));
85 * sel_netport_find - Search for a port record
90 * Search the network port table and return the matching record. If an entry
91 * can not be found in the table return NULL.
94 static struct sel_netport *sel_netport_find(u8 protocol, u16 pnum)
97 struct sel_netport *port;
99 idx = sel_netport_hashfn(pnum);
100 list_for_each_entry_rcu(port, &sel_netport_hash[idx].list, list)
101 if (port->psec.port == pnum && port->psec.protocol == protocol)
108 * sel_netport_insert - Insert a new port into the table
109 * @port: the new port record
112 * Add a new port record to the network address hash table.
115 static void sel_netport_insert(struct sel_netport *port)
119 /* we need to impose a limit on the growth of the hash table so check
120 * this bucket to make sure it is within the specified bounds */
121 idx = sel_netport_hashfn(port->psec.port);
122 list_add_rcu(&port->list, &sel_netport_hash[idx].list);
123 if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) {
124 struct sel_netport *tail;
126 rcu_dereference_protected(
127 sel_netport_hash[idx].list.prev,
128 lockdep_is_held(&sel_netport_lock)),
129 struct sel_netport, list);
130 list_del_rcu(&tail->list);
131 kfree_rcu(tail, rcu);
133 sel_netport_hash[idx].size++;
137 * sel_netport_sid_slow - Lookup the SID of a network address using the policy
138 * @protocol: protocol
143 * This function determines the SID of a network port by quering the security
144 * policy. The result is added to the network port table to speedup future
145 * queries. Returns zero on success, negative values on failure.
148 static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
151 struct sel_netport *port;
152 struct sel_netport *new = NULL;
154 spin_lock_bh(&sel_netport_lock);
155 port = sel_netport_find(protocol, pnum);
157 *sid = port->psec.sid;
158 spin_unlock_bh(&sel_netport_lock);
161 new = kzalloc(sizeof(*new), GFP_ATOMIC);
164 ret = security_port_sid(protocol, pnum, sid);
168 new->psec.port = pnum;
169 new->psec.protocol = protocol;
170 new->psec.sid = *sid;
171 sel_netport_insert(new);
174 spin_unlock_bh(&sel_netport_lock);
177 "SELinux: failure in sel_netport_sid_slow(),"
178 " unable to determine network port label\n");
185 * sel_netport_sid - Lookup the SID of a network port
186 * @protocol: protocol
191 * This function determines the SID of a network port using the fastest method
192 * possible. First the port table is queried, but if an entry can't be found
193 * then the policy is queried and the result is added to the table to speedup
194 * future queries. Returns zero on success, negative values on failure.
197 int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid)
199 struct sel_netport *port;
202 port = sel_netport_find(protocol, pnum);
204 *sid = port->psec.sid;
210 return sel_netport_sid_slow(protocol, pnum, sid);
214 * sel_netport_flush - Flush the entire network port table
217 * Remove all entries from the network address table.
220 static void sel_netport_flush(void)
223 struct sel_netport *port, *port_tmp;
225 spin_lock_bh(&sel_netport_lock);
226 for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
227 list_for_each_entry_safe(port, port_tmp,
228 &sel_netport_hash[idx].list, list) {
229 list_del_rcu(&port->list);
230 kfree_rcu(port, rcu);
232 sel_netport_hash[idx].size = 0;
234 spin_unlock_bh(&sel_netport_lock);
237 static int sel_netport_avc_callback(u32 event)
239 if (event == AVC_CALLBACK_RESET) {
246 static __init int sel_netport_init(void)
251 if (!selinux_enabled)
254 for (iter = 0; iter < SEL_NETPORT_HASH_SIZE; iter++) {
255 INIT_LIST_HEAD(&sel_netport_hash[iter].list);
256 sel_netport_hash[iter].size = 0;
259 ret = avc_add_callback(sel_netport_avc_callback, AVC_CALLBACK_RESET);
261 panic("avc_add_callback() failed, error %d\n", ret);
266 __initcall(sel_netport_init);