1 // SPDX-License-Identifier: GPL-2.0-only
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.
9 * Author: Paul Moore <paul@paul-moore.com>
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)
17 * (c) Copyright Hewlett-Packard Development Company, L.P., 2008
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>
26 #include <linux/in6.h>
28 #include <linux/ipv6.h>
35 #define SEL_NETPORT_HASH_SIZE 256
36 #define SEL_NETPORT_HASH_BKT_LIMIT 16
38 struct sel_netport_bkt {
40 struct list_head list;
44 struct netport_security_struct psec;
46 struct list_head list;
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
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];
61 * sel_netport_hashfn - Hashing function for the port table
65 * This is the hashing function for the port table, it returns the bucket
66 * number for the given port.
69 static unsigned int sel_netport_hashfn(u16 pnum)
71 return (pnum & (SEL_NETPORT_HASH_SIZE - 1));
75 * sel_netport_find - Search for a port record
80 * Search the network port table and return the matching record. If an entry
81 * can not be found in the table return NULL.
84 static struct sel_netport *sel_netport_find(u8 protocol, u16 pnum)
87 struct sel_netport *port;
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)
98 * sel_netport_insert - Insert a new port into the table
99 * @port: the new port record
102 * Add a new port record to the network address hash table.
105 static void sel_netport_insert(struct sel_netport *port)
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;
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);
123 sel_netport_hash[idx].size++;
127 * sel_netport_sid_slow - Lookup the SID of a network address using the policy
128 * @protocol: protocol
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.
138 static int sel_netport_sid_slow(u8 protocol, u16 pnum, u32 *sid)
141 struct sel_netport *port;
142 struct sel_netport *new = NULL;
144 spin_lock_bh(&sel_netport_lock);
145 port = sel_netport_find(protocol, pnum);
147 *sid = port->psec.sid;
148 spin_unlock_bh(&sel_netport_lock);
151 new = kzalloc(sizeof(*new), GFP_ATOMIC);
154 ret = security_port_sid(&selinux_state, protocol, pnum, sid);
158 new->psec.port = pnum;
159 new->psec.protocol = protocol;
160 new->psec.sid = *sid;
161 sel_netport_insert(new);
164 spin_unlock_bh(&sel_netport_lock);
166 pr_warn("SELinux: failure in %s(), unable to determine network port label\n",
174 * sel_netport_sid - Lookup the SID of a network port
175 * @protocol: protocol
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.
186 int sel_netport_sid(u8 protocol, u16 pnum, u32 *sid)
188 struct sel_netport *port;
191 port = sel_netport_find(protocol, pnum);
193 *sid = port->psec.sid;
199 return sel_netport_sid_slow(protocol, pnum, sid);
203 * sel_netport_flush - Flush the entire network port table
206 * Remove all entries from the network address table.
209 void sel_netport_flush(void)
212 struct sel_netport *port, *port_tmp;
214 spin_lock_bh(&sel_netport_lock);
215 for (idx = 0; idx < SEL_NETPORT_HASH_SIZE; idx++) {
216 list_for_each_entry_safe(port, port_tmp,
217 &sel_netport_hash[idx].list, list) {
218 list_del_rcu(&port->list);
219 kfree_rcu(port, rcu);
221 sel_netport_hash[idx].size = 0;
223 spin_unlock_bh(&sel_netport_lock);
226 static __init int sel_netport_init(void)
230 if (!selinux_enabled)
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;
241 __initcall(sel_netport_init);