Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc
[cris-mirror.git] / security / selinux / netif.c
blobd6095d63d831a63999f1921fbed460a94140fc39
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/slab.h>
20 #include <linux/stddef.h>
21 #include <linux/kernel.h>
22 #include <linux/list.h>
23 #include <linux/notifier.h>
24 #include <linux/netdevice.h>
25 #include <linux/rcupdate.h>
26 #include <net/net_namespace.h>
28 #include "security.h"
29 #include "objsec.h"
30 #include "netif.h"
32 #define SEL_NETIF_HASH_SIZE 64
33 #define SEL_NETIF_HASH_MAX 1024
35 struct sel_netif {
36 struct list_head list;
37 struct netif_security_struct nsec;
38 struct rcu_head rcu_head;
41 static u32 sel_netif_total;
42 static LIST_HEAD(sel_netif_list);
43 static DEFINE_SPINLOCK(sel_netif_lock);
44 static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
46 /**
47 * sel_netif_hashfn - Hashing function for the interface table
48 * @ifindex: the network interface
50 * Description:
51 * This is the hashing function for the network interface table, it returns the
52 * bucket number for the given interface.
55 static inline u32 sel_netif_hashfn(int ifindex)
57 return (ifindex & (SEL_NETIF_HASH_SIZE - 1));
60 /**
61 * sel_netif_find - Search for an interface record
62 * @ifindex: the network interface
64 * Description:
65 * Search the network interface table and return the record matching @ifindex.
66 * If an entry can not be found in the table return NULL.
69 static inline struct sel_netif *sel_netif_find(int ifindex)
71 int idx = sel_netif_hashfn(ifindex);
72 struct sel_netif *netif;
74 list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list)
75 /* all of the devices should normally fit in the hash, so we
76 * optimize for that case */
77 if (likely(netif->nsec.ifindex == ifindex))
78 return netif;
80 return NULL;
83 /**
84 * sel_netif_insert - Insert a new interface into the table
85 * @netif: the new interface record
87 * Description:
88 * Add a new interface record to the network interface hash table. Returns
89 * zero on success, negative values on failure.
92 static int sel_netif_insert(struct sel_netif *netif)
94 int idx;
96 if (sel_netif_total >= SEL_NETIF_HASH_MAX)
97 return -ENOSPC;
99 idx = sel_netif_hashfn(netif->nsec.ifindex);
100 list_add_rcu(&netif->list, &sel_netif_hash[idx]);
101 sel_netif_total++;
103 return 0;
107 * sel_netif_free - Frees an interface entry
108 * @p: the entry's RCU field
110 * Description:
111 * This function is designed to be used as a callback to the call_rcu()
112 * function so that memory allocated to a hash table interface entry can be
113 * released safely.
116 static void sel_netif_free(struct rcu_head *p)
118 struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
119 kfree(netif);
123 * sel_netif_destroy - Remove an interface record from the table
124 * @netif: the existing interface record
126 * Description:
127 * Remove an existing interface record from the network interface table.
130 static void sel_netif_destroy(struct sel_netif *netif)
132 list_del_rcu(&netif->list);
133 sel_netif_total--;
134 call_rcu(&netif->rcu_head, sel_netif_free);
138 * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
139 * @ifindex: the network interface
140 * @sid: interface SID
142 * Description:
143 * This function determines the SID of a network interface by quering the
144 * security policy. The result is added to the network interface table to
145 * speedup future queries. Returns zero on success, negative values on
146 * failure.
149 static int sel_netif_sid_slow(int ifindex, u32 *sid)
151 int ret;
152 struct sel_netif *netif;
153 struct sel_netif *new = NULL;
154 struct net_device *dev;
156 /* NOTE: we always use init's network namespace since we don't
157 * currently support containers */
159 dev = dev_get_by_index(&init_net, ifindex);
160 if (unlikely(dev == NULL)) {
161 printk(KERN_WARNING
162 "SELinux: failure in sel_netif_sid_slow(),"
163 " invalid network interface (%d)\n", ifindex);
164 return -ENOENT;
167 spin_lock_bh(&sel_netif_lock);
168 netif = sel_netif_find(ifindex);
169 if (netif != NULL) {
170 *sid = netif->nsec.sid;
171 ret = 0;
172 goto out;
174 new = kzalloc(sizeof(*new), GFP_ATOMIC);
175 if (new == NULL) {
176 ret = -ENOMEM;
177 goto out;
179 ret = security_netif_sid(dev->name, &new->nsec.sid);
180 if (ret != 0)
181 goto out;
182 new->nsec.ifindex = ifindex;
183 ret = sel_netif_insert(new);
184 if (ret != 0)
185 goto out;
186 *sid = new->nsec.sid;
188 out:
189 spin_unlock_bh(&sel_netif_lock);
190 dev_put(dev);
191 if (unlikely(ret)) {
192 printk(KERN_WARNING
193 "SELinux: failure in sel_netif_sid_slow(),"
194 " unable to determine network interface label (%d)\n",
195 ifindex);
196 kfree(new);
198 return ret;
202 * sel_netif_sid - Lookup the SID of a network interface
203 * @ifindex: the network interface
204 * @sid: interface SID
206 * Description:
207 * This function determines the SID of a network interface using the fastest
208 * method possible. First the interface table is queried, but if an entry
209 * can't be found then the policy is queried and the result is added to the
210 * table to speedup future queries. Returns zero on success, negative values
211 * on failure.
214 int sel_netif_sid(int ifindex, u32 *sid)
216 struct sel_netif *netif;
218 rcu_read_lock();
219 netif = sel_netif_find(ifindex);
220 if (likely(netif != NULL)) {
221 *sid = netif->nsec.sid;
222 rcu_read_unlock();
223 return 0;
225 rcu_read_unlock();
227 return sel_netif_sid_slow(ifindex, sid);
231 * sel_netif_kill - Remove an entry from the network interface table
232 * @ifindex: the network interface
234 * Description:
235 * This function removes the entry matching @ifindex from the network interface
236 * table if it exists.
239 static void sel_netif_kill(int ifindex)
241 struct sel_netif *netif;
243 rcu_read_lock();
244 spin_lock_bh(&sel_netif_lock);
245 netif = sel_netif_find(ifindex);
246 if (netif)
247 sel_netif_destroy(netif);
248 spin_unlock_bh(&sel_netif_lock);
249 rcu_read_unlock();
253 * sel_netif_flush - Flush the entire network interface table
255 * Description:
256 * Remove all entries from the network interface table.
259 static void sel_netif_flush(void)
261 int idx;
262 struct sel_netif *netif;
264 spin_lock_bh(&sel_netif_lock);
265 for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
266 list_for_each_entry(netif, &sel_netif_hash[idx], list)
267 sel_netif_destroy(netif);
268 spin_unlock_bh(&sel_netif_lock);
271 static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
272 u16 class, u32 perms, u32 *retained)
274 if (event == AVC_CALLBACK_RESET) {
275 sel_netif_flush();
276 synchronize_net();
278 return 0;
281 static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
282 unsigned long event, void *ptr)
284 struct net_device *dev = ptr;
286 if (dev_net(dev) != &init_net)
287 return NOTIFY_DONE;
289 if (event == NETDEV_DOWN)
290 sel_netif_kill(dev->ifindex);
292 return NOTIFY_DONE;
295 static struct notifier_block sel_netif_netdev_notifier = {
296 .notifier_call = sel_netif_netdev_notifier_handler,
299 static __init int sel_netif_init(void)
301 int i, err;
303 if (!selinux_enabled)
304 return 0;
306 for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
307 INIT_LIST_HEAD(&sel_netif_hash[i]);
309 register_netdevice_notifier(&sel_netif_netdev_notifier);
311 err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET,
312 SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
313 if (err)
314 panic("avc_add_callback() failed, error %d\n", err);
316 return err;
319 __initcall(sel_netif_init);