blob: c658b84c31966b177e3c9cb3e980c5ad667898af [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Network interface table.
3 *
4 * Network interfaces (devices) do not have a security field, so we
5 * maintain a table associating each interface with a SID.
6 *
7 * Author: James Morris <jmorris@redhat.com>
8 *
9 * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
Paul Mooree8bfdb92008-01-29 08:38:08 -050010 * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
Eric Paris338366c2008-04-18 17:38:22 -040011 * Paul Moore <paul.moore@hp.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 *
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.
16 */
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>
Eric W. Biedermane9dc8652007-09-12 13:02:17 +020025#include <net/net_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026
27#include "security.h"
28#include "objsec.h"
29#include "netif.h"
30
31#define SEL_NETIF_HASH_SIZE 64
32#define SEL_NETIF_HASH_MAX 1024
33
Eric Paris338366c2008-04-18 17:38:22 -040034struct sel_netif {
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 struct list_head list;
36 struct netif_security_struct nsec;
37 struct rcu_head rcu_head;
38};
39
40static u32 sel_netif_total;
41static LIST_HEAD(sel_netif_list);
42static DEFINE_SPINLOCK(sel_netif_lock);
43static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
44
Paul Mooree8bfdb92008-01-29 08:38:08 -050045/**
46 * sel_netif_hashfn - Hashing function for the interface table
47 * @ifindex: the network interface
48 *
49 * Description:
50 * This is the hashing function for the network interface table, it returns the
51 * bucket number for the given interface.
52 *
53 */
54static inline u32 sel_netif_hashfn(int ifindex)
Linus Torvalds1da177e2005-04-16 15:20:36 -070055{
Paul Mooree8bfdb92008-01-29 08:38:08 -050056 return (ifindex & (SEL_NETIF_HASH_SIZE - 1));
Linus Torvalds1da177e2005-04-16 15:20:36 -070057}
58
Paul Mooree8bfdb92008-01-29 08:38:08 -050059/**
60 * sel_netif_find - Search for an interface record
61 * @ifindex: the network interface
62 *
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.
66 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 */
Paul Mooree8bfdb92008-01-29 08:38:08 -050068static inline struct sel_netif *sel_netif_find(int ifindex)
Linus Torvalds1da177e2005-04-16 15:20:36 -070069{
Paul Mooree8bfdb92008-01-29 08:38:08 -050070 int idx = sel_netif_hashfn(ifindex);
71 struct sel_netif *netif;
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
Paul Mooree8bfdb92008-01-29 08:38:08 -050073 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))
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 return netif;
Paul Mooree8bfdb92008-01-29 08:38:08 -050078
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 return NULL;
80}
81
Paul Mooree8bfdb92008-01-29 08:38:08 -050082/**
83 * sel_netif_insert - Insert a new interface into the table
84 * @netif: the new interface record
85 *
86 * Description:
87 * Add a new interface record to the network interface hash table. Returns
88 * zero on success, negative values on failure.
89 *
90 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070091static int sel_netif_insert(struct sel_netif *netif)
92{
Paul Mooree8bfdb92008-01-29 08:38:08 -050093 int idx;
Eric Paris338366c2008-04-18 17:38:22 -040094
Paul Mooree8bfdb92008-01-29 08:38:08 -050095 if (sel_netif_total >= SEL_NETIF_HASH_MAX)
96 return -ENOSPC;
Eric Paris338366c2008-04-18 17:38:22 -040097
Paul Mooree8bfdb92008-01-29 08:38:08 -050098 idx = sel_netif_hashfn(netif->nsec.ifindex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 list_add_rcu(&netif->list, &sel_netif_hash[idx]);
100 sel_netif_total++;
Paul Mooree8bfdb92008-01-29 08:38:08 -0500101
102 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103}
104
Paul Mooree8bfdb92008-01-29 08:38:08 -0500105/**
106 * sel_netif_free - Frees an interface entry
107 * @p: the entry's RCU field
108 *
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.
113 *
114 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115static void sel_netif_free(struct rcu_head *p)
116{
117 struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 kfree(netif);
119}
120
Paul Mooree8bfdb92008-01-29 08:38:08 -0500121/**
122 * sel_netif_destroy - Remove an interface record from the table
123 * @netif: the existing interface record
124 *
125 * Description:
126 * Remove an existing interface record from the network interface table.
127 *
128 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129static void sel_netif_destroy(struct sel_netif *netif)
130{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 list_del_rcu(&netif->list);
132 sel_netif_total--;
133 call_rcu(&netif->rcu_head, sel_netif_free);
134}
135
Paul Mooree8bfdb92008-01-29 08:38:08 -0500136/**
137 * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
138 * @ifindex: the network interface
139 * @sid: interface SID
140 *
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.
146 *
147 */
148static int sel_netif_sid_slow(int ifindex, u32 *sid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149{
150 int ret;
Paul Mooree8bfdb92008-01-29 08:38:08 -0500151 struct sel_netif *netif;
152 struct sel_netif *new = NULL;
153 struct net_device *dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154
Paul Mooree8bfdb92008-01-29 08:38:08 -0500155 /* NOTE: we always use init's network namespace since we don't
156 * currently support containers */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
Paul Mooree8bfdb92008-01-29 08:38:08 -0500158 dev = dev_get_by_index(&init_net, ifindex);
Paul Moore71f1cb02008-01-29 08:51:16 -0500159 if (unlikely(dev == NULL)) {
160 printk(KERN_WARNING
161 "SELinux: failure in sel_netif_sid_slow(),"
162 " invalid network interface (%d)\n", ifindex);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500163 return -ENOENT;
Paul Moore71f1cb02008-01-29 08:51:16 -0500164 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 spin_lock_bh(&sel_netif_lock);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500167 netif = sel_netif_find(ifindex);
168 if (netif != NULL) {
169 *sid = netif->nsec.sid;
170 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 goto out;
172 }
Paul Mooree8bfdb92008-01-29 08:38:08 -0500173 new = kzalloc(sizeof(*new), GFP_ATOMIC);
174 if (new == NULL) {
175 ret = -ENOMEM;
176 goto out;
177 }
178 ret = security_netif_sid(dev->name, &new->nsec.sid);
179 if (ret != 0)
180 goto out;
181 new->nsec.ifindex = ifindex;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 ret = sel_netif_insert(new);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500183 if (ret != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 goto out;
Paul Mooree8bfdb92008-01-29 08:38:08 -0500185 *sid = new->nsec.sid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187out:
Paul Mooree8bfdb92008-01-29 08:38:08 -0500188 spin_unlock_bh(&sel_netif_lock);
189 dev_put(dev);
Paul Moore71f1cb02008-01-29 08:51:16 -0500190 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);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500195 kfree(new);
Paul Moore71f1cb02008-01-29 08:51:16 -0500196 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 return ret;
198}
199
Paul Mooree8bfdb92008-01-29 08:38:08 -0500200/**
201 * sel_netif_sid - Lookup the SID of a network interface
202 * @ifindex: the network interface
203 * @sid: interface SID
204 *
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.
211 *
212 */
213int sel_netif_sid(int ifindex, u32 *sid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 struct sel_netif *netif;
216
217 rcu_read_lock();
Paul Mooree8bfdb92008-01-29 08:38:08 -0500218 netif = sel_netif_find(ifindex);
219 if (likely(netif != NULL)) {
220 *sid = netif->nsec.sid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 rcu_read_unlock();
Paul Mooree8bfdb92008-01-29 08:38:08 -0500222 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 rcu_read_unlock();
Paul Mooree8bfdb92008-01-29 08:38:08 -0500225
226 return sel_netif_sid_slow(ifindex, sid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227}
228
Paul Mooree8bfdb92008-01-29 08:38:08 -0500229/**
230 * sel_netif_kill - Remove an entry from the network interface table
231 * @ifindex: the network interface
232 *
233 * Description:
234 * This function removes the entry matching @ifindex from the network interface
235 * table if it exists.
236 *
237 */
238static void sel_netif_kill(int ifindex)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239{
240 struct sel_netif *netif;
241
242 spin_lock_bh(&sel_netif_lock);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500243 netif = sel_netif_find(ifindex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 if (netif)
245 sel_netif_destroy(netif);
246 spin_unlock_bh(&sel_netif_lock);
247}
248
Paul Mooree8bfdb92008-01-29 08:38:08 -0500249/**
250 * sel_netif_flush - Flush the entire network interface table
251 *
252 * Description:
253 * Remove all entries from the network interface table.
254 *
255 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256static void sel_netif_flush(void)
257{
258 int idx;
Paul Mooree8bfdb92008-01-29 08:38:08 -0500259 struct sel_netif *netif;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
261 spin_lock_bh(&sel_netif_lock);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500262 for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 list_for_each_entry(netif, &sel_netif_hash[idx], list)
264 sel_netif_destroy(netif);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 spin_unlock_bh(&sel_netif_lock);
266}
267
268static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
Eric Paris338366c2008-04-18 17:38:22 -0400269 u16 class, u32 perms, u32 *retained)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270{
271 if (event == AVC_CALLBACK_RESET) {
272 sel_netif_flush();
273 synchronize_net();
274 }
275 return 0;
276}
277
278static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
Eric Paris338366c2008-04-18 17:38:22 -0400279 unsigned long event, void *ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280{
281 struct net_device *dev = ptr;
282
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900283 if (dev_net(dev) != &init_net)
Eric W. Biedermane9dc8652007-09-12 13:02:17 +0200284 return NOTIFY_DONE;
285
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 if (event == NETDEV_DOWN)
Paul Mooree8bfdb92008-01-29 08:38:08 -0500287 sel_netif_kill(dev->ifindex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288
289 return NOTIFY_DONE;
290}
291
292static struct notifier_block sel_netif_netdev_notifier = {
293 .notifier_call = sel_netif_netdev_notifier_handler,
294};
295
296static __init int sel_netif_init(void)
297{
Paul Mooree8bfdb92008-01-29 08:38:08 -0500298 int i, err;
Eric Paris338366c2008-04-18 17:38:22 -0400299
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 if (!selinux_enabled)
Paul Mooree8bfdb92008-01-29 08:38:08 -0500301 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302
303 for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
304 INIT_LIST_HEAD(&sel_netif_hash[i]);
305
306 register_netdevice_notifier(&sel_netif_netdev_notifier);
Eric Paris338366c2008-04-18 17:38:22 -0400307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET,
Eric Paris338366c2008-04-18 17:38:22 -0400309 SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 if (err)
311 panic("avc_add_callback() failed, error %d\n", err);
312
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 return err;
314}
315
316__initcall(sel_netif_init);
317