[MIPS] Add support for MIPS CMP platform.
[linux-2.6/linux-mips/linux-dm7025.git] / security / selinux / netif.c
blobb4e14bc0bf32bf6d0a9ae948d697912ca11e8769
1 /*
2 * Network interface table.
4 * Network interfaces (devices) do not have a security field, so we
5 * maintain a table associating each interface with a SID.
7 * Author: James Morris <jmorris@redhat.com>
9 * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
10 * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
11 * Paul Moore <paul.moore@hp.com>
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2,
15 * as published by the Free Software Foundation.
17 #include <linux/init.h>
18 #include <linux/types.h>
19 #include <linux/stddef.h>
20 #include <linux/kernel.h>
21 #include <linux/list.h>
22 #include <linux/notifier.h>
23 #include <linux/netdevice.h>
24 #include <linux/rcupdate.h>
25 #include <net/net_namespace.h>
27 #include "security.h"
28 #include "objsec.h"
29 #include "netif.h"
31 #define SEL_NETIF_HASH_SIZE 64
32 #define SEL_NETIF_HASH_MAX 1024
34 struct sel_netif {
35 struct list_head list;
36 struct netif_security_struct nsec;
37 struct rcu_head rcu_head;
40 static u32 sel_netif_total;
41 static LIST_HEAD(sel_netif_list);
42 static DEFINE_SPINLOCK(sel_netif_lock);
43 static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
45 /**
46 * sel_netif_hashfn - Hashing function for the interface table
47 * @ifindex: the network interface
49 * Description:
50 * This is the hashing function for the network interface table, it returns the
51 * bucket number for the given interface.
54 static inline u32 sel_netif_hashfn(int ifindex)
56 return (ifindex & (SEL_NETIF_HASH_SIZE - 1));
59 /**
60 * sel_netif_find - Search for an interface record
61 * @ifindex: the network interface
63 * Description:
64 * Search the network interface table and return the record matching @ifindex.
65 * If an entry can not be found in the table return NULL.
68 static inline struct sel_netif *sel_netif_find(int ifindex)
70 int idx = sel_netif_hashfn(ifindex);
71 struct sel_netif *netif;
73 list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list)
74 /* all of the devices should normally fit in the hash, so we
75 * optimize for that case */
76 if (likely(netif->nsec.ifindex == ifindex))
77 return netif;
79 return NULL;
82 /**
83 * sel_netif_insert - Insert a new interface into the table
84 * @netif: the new interface record
86 * Description:
87 * Add a new interface record to the network interface hash table. Returns
88 * zero on success, negative values on failure.
91 static int sel_netif_insert(struct sel_netif *netif)
93 int idx;
95 if (sel_netif_total >= SEL_NETIF_HASH_MAX)
96 return -ENOSPC;
98 idx = sel_netif_hashfn(netif->nsec.ifindex);
99 list_add_rcu(&netif->list, &sel_netif_hash[idx]);
100 sel_netif_total++;
102 return 0;
106 * sel_netif_free - Frees an interface entry
107 * @p: the entry's RCU field
109 * Description:
110 * This function is designed to be used as a callback to the call_rcu()
111 * function so that memory allocated to a hash table interface entry can be
112 * released safely.
115 static void sel_netif_free(struct rcu_head *p)
117 struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
118 kfree(netif);
122 * sel_netif_destroy - Remove an interface record from the table
123 * @netif: the existing interface record
125 * Description:
126 * Remove an existing interface record from the network interface table.
129 static void sel_netif_destroy(struct sel_netif *netif)
131 list_del_rcu(&netif->list);
132 sel_netif_total--;
133 call_rcu(&netif->rcu_head, sel_netif_free);
137 * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
138 * @ifindex: the network interface
139 * @sid: interface SID
141 * Description:
142 * This function determines the SID of a network interface by quering the
143 * security policy. The result is added to the network interface table to
144 * speedup future queries. Returns zero on success, negative values on
145 * failure.
148 static int sel_netif_sid_slow(int ifindex, u32 *sid)
150 int ret;
151 struct sel_netif *netif;
152 struct sel_netif *new = NULL;
153 struct net_device *dev;
155 /* NOTE: we always use init's network namespace since we don't
156 * currently support containers */
158 dev = dev_get_by_index(&init_net, ifindex);
159 if (unlikely(dev == NULL)) {
160 printk(KERN_WARNING
161 "SELinux: failure in sel_netif_sid_slow(),"
162 " invalid network interface (%d)\n", ifindex);
163 return -ENOENT;
166 spin_lock_bh(&sel_netif_lock);
167 netif = sel_netif_find(ifindex);
168 if (netif != NULL) {
169 *sid = netif->nsec.sid;
170 ret = 0;
171 goto out;
173 new = kzalloc(sizeof(*new), GFP_ATOMIC);
174 if (new == NULL) {
175 ret = -ENOMEM;
176 goto out;
178 ret = security_netif_sid(dev->name, &new->nsec.sid);
179 if (ret != 0)
180 goto out;
181 new->nsec.ifindex = ifindex;
182 ret = sel_netif_insert(new);
183 if (ret != 0)
184 goto out;
185 *sid = new->nsec.sid;
187 out:
188 spin_unlock_bh(&sel_netif_lock);
189 dev_put(dev);
190 if (unlikely(ret)) {
191 printk(KERN_WARNING
192 "SELinux: failure in sel_netif_sid_slow(),"
193 " unable to determine network interface label (%d)\n",
194 ifindex);
195 kfree(new);
197 return ret;
201 * sel_netif_sid - Lookup the SID of a network interface
202 * @ifindex: the network interface
203 * @sid: interface SID
205 * Description:
206 * This function determines the SID of a network interface using the fastest
207 * method possible. First the interface table is queried, but if an entry
208 * can't be found then the policy is queried and the result is added to the
209 * table to speedup future queries. Returns zero on success, negative values
210 * on failure.
213 int sel_netif_sid(int ifindex, u32 *sid)
215 struct sel_netif *netif;
217 rcu_read_lock();
218 netif = sel_netif_find(ifindex);
219 if (likely(netif != NULL)) {
220 *sid = netif->nsec.sid;
221 rcu_read_unlock();
222 return 0;
224 rcu_read_unlock();
226 return sel_netif_sid_slow(ifindex, sid);
230 * sel_netif_kill - Remove an entry from the network interface table
231 * @ifindex: the network interface
233 * Description:
234 * This function removes the entry matching @ifindex from the network interface
235 * table if it exists.
238 static void sel_netif_kill(int ifindex)
240 struct sel_netif *netif;
242 rcu_read_lock();
243 spin_lock_bh(&sel_netif_lock);
244 netif = sel_netif_find(ifindex);
245 if (netif)
246 sel_netif_destroy(netif);
247 spin_unlock_bh(&sel_netif_lock);
248 rcu_read_unlock();
252 * sel_netif_flush - Flush the entire network interface table
254 * Description:
255 * Remove all entries from the network interface table.
258 static void sel_netif_flush(void)
260 int idx;
261 struct sel_netif *netif;
263 spin_lock_bh(&sel_netif_lock);
264 for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
265 list_for_each_entry(netif, &sel_netif_hash[idx], list)
266 sel_netif_destroy(netif);
267 spin_unlock_bh(&sel_netif_lock);
270 static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
271 u16 class, u32 perms, u32 *retained)
273 if (event == AVC_CALLBACK_RESET) {
274 sel_netif_flush();
275 synchronize_net();
277 return 0;
280 static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
281 unsigned long event, void *ptr)
283 struct net_device *dev = ptr;
285 if (dev_net(dev) != &init_net)
286 return NOTIFY_DONE;
288 if (event == NETDEV_DOWN)
289 sel_netif_kill(dev->ifindex);
291 return NOTIFY_DONE;
294 static struct notifier_block sel_netif_netdev_notifier = {
295 .notifier_call = sel_netif_netdev_notifier_handler,
298 static __init int sel_netif_init(void)
300 int i, err;
302 if (!selinux_enabled)
303 return 0;
305 for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
306 INIT_LIST_HEAD(&sel_netif_hash[i]);
308 register_netdevice_notifier(&sel_netif_netdev_notifier);
310 err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET,
311 SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
312 if (err)
313 panic("avc_add_callback() failed, error %d\n", err);
315 return err;
318 __initcall(sel_netif_init);