blob: 9c8a82aa8baf17b2bdcf01e822a243c8d3a0d8c1 [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.
11 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070034struct sel_netif
35{
36 struct list_head list;
37 struct netif_security_struct nsec;
38 struct rcu_head rcu_head;
39};
40
41static u32 sel_netif_total;
42static LIST_HEAD(sel_netif_list);
43static DEFINE_SPINLOCK(sel_netif_lock);
44static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE];
45
Paul Mooree8bfdb92008-01-29 08:38:08 -050046/**
47 * sel_netif_hashfn - Hashing function for the interface table
48 * @ifindex: the network interface
49 *
50 * Description:
51 * This is the hashing function for the network interface table, it returns the
52 * bucket number for the given interface.
53 *
54 */
55static inline u32 sel_netif_hashfn(int ifindex)
Linus Torvalds1da177e2005-04-16 15:20:36 -070056{
Paul Mooree8bfdb92008-01-29 08:38:08 -050057 return (ifindex & (SEL_NETIF_HASH_SIZE - 1));
Linus Torvalds1da177e2005-04-16 15:20:36 -070058}
59
Paul Mooree8bfdb92008-01-29 08:38:08 -050060/**
61 * sel_netif_find - Search for an interface record
62 * @ifindex: the network interface
63 *
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.
67 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 */
Paul Mooree8bfdb92008-01-29 08:38:08 -050069static inline struct sel_netif *sel_netif_find(int ifindex)
Linus Torvalds1da177e2005-04-16 15:20:36 -070070{
Paul Mooree8bfdb92008-01-29 08:38:08 -050071 int idx = sel_netif_hashfn(ifindex);
72 struct sel_netif *netif;
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
Paul Mooree8bfdb92008-01-29 08:38:08 -050074 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))
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 return netif;
Paul Mooree8bfdb92008-01-29 08:38:08 -050079
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 return NULL;
81}
82
Paul Mooree8bfdb92008-01-29 08:38:08 -050083/**
84 * sel_netif_insert - Insert a new interface into the table
85 * @netif: the new interface record
86 *
87 * Description:
88 * Add a new interface record to the network interface hash table. Returns
89 * zero on success, negative values on failure.
90 *
91 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070092static int sel_netif_insert(struct sel_netif *netif)
93{
Paul Mooree8bfdb92008-01-29 08:38:08 -050094 int idx;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
Paul Mooree8bfdb92008-01-29 08:38:08 -050096 if (sel_netif_total >= SEL_NETIF_HASH_MAX)
97 return -ENOSPC;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
Paul Mooree8bfdb92008-01-29 08:38:08 -050099 idx = sel_netif_hashfn(netif->nsec.ifindex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 list_add_rcu(&netif->list, &sel_netif_hash[idx]);
101 sel_netif_total++;
Paul Mooree8bfdb92008-01-29 08:38:08 -0500102
103 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104}
105
Paul Mooree8bfdb92008-01-29 08:38:08 -0500106/**
107 * sel_netif_free - Frees an interface entry
108 * @p: the entry's RCU field
109 *
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.
114 *
115 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116static void sel_netif_free(struct rcu_head *p)
117{
118 struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 kfree(netif);
120}
121
Paul Mooree8bfdb92008-01-29 08:38:08 -0500122/**
123 * sel_netif_destroy - Remove an interface record from the table
124 * @netif: the existing interface record
125 *
126 * Description:
127 * Remove an existing interface record from the network interface table.
128 *
129 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130static void sel_netif_destroy(struct sel_netif *netif)
131{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 list_del_rcu(&netif->list);
133 sel_netif_total--;
134 call_rcu(&netif->rcu_head, sel_netif_free);
135}
136
Paul Mooree8bfdb92008-01-29 08:38:08 -0500137/**
138 * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
139 * @ifindex: the network interface
140 * @sid: interface SID
141 *
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.
147 *
148 */
149static int sel_netif_sid_slow(int ifindex, u32 *sid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
151 int ret;
Paul Mooree8bfdb92008-01-29 08:38:08 -0500152 struct sel_netif *netif;
153 struct sel_netif *new = NULL;
154 struct net_device *dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
Paul Mooree8bfdb92008-01-29 08:38:08 -0500156 /* NOTE: we always use init's network namespace since we don't
157 * currently support containers */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
Paul Mooree8bfdb92008-01-29 08:38:08 -0500159 dev = dev_get_by_index(&init_net, ifindex);
Paul Moore71f1cb02008-01-29 08:51:16 -0500160 if (unlikely(dev == NULL)) {
161 printk(KERN_WARNING
162 "SELinux: failure in sel_netif_sid_slow(),"
163 " invalid network interface (%d)\n", ifindex);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500164 return -ENOENT;
Paul Moore71f1cb02008-01-29 08:51:16 -0500165 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 spin_lock_bh(&sel_netif_lock);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500168 netif = sel_netif_find(ifindex);
169 if (netif != NULL) {
170 *sid = netif->nsec.sid;
171 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 goto out;
173 }
Paul Mooree8bfdb92008-01-29 08:38:08 -0500174 new = kzalloc(sizeof(*new), GFP_ATOMIC);
175 if (new == NULL) {
176 ret = -ENOMEM;
177 goto out;
178 }
179 ret = security_netif_sid(dev->name, &new->nsec.sid);
180 if (ret != 0)
181 goto out;
182 new->nsec.ifindex = ifindex;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 ret = sel_netif_insert(new);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500184 if (ret != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 goto out;
Paul Mooree8bfdb92008-01-29 08:38:08 -0500186 *sid = new->nsec.sid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188out:
Paul Mooree8bfdb92008-01-29 08:38:08 -0500189 spin_unlock_bh(&sel_netif_lock);
190 dev_put(dev);
Paul Moore71f1cb02008-01-29 08:51:16 -0500191 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);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500196 kfree(new);
Paul Moore71f1cb02008-01-29 08:51:16 -0500197 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 return ret;
199}
200
Paul Mooree8bfdb92008-01-29 08:38:08 -0500201/**
202 * sel_netif_sid - Lookup the SID of a network interface
203 * @ifindex: the network interface
204 * @sid: interface SID
205 *
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.
212 *
213 */
214int sel_netif_sid(int ifindex, u32 *sid)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 struct sel_netif *netif;
217
218 rcu_read_lock();
Paul Mooree8bfdb92008-01-29 08:38:08 -0500219 netif = sel_netif_find(ifindex);
220 if (likely(netif != NULL)) {
221 *sid = netif->nsec.sid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 rcu_read_unlock();
Paul Mooree8bfdb92008-01-29 08:38:08 -0500223 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 rcu_read_unlock();
Paul Mooree8bfdb92008-01-29 08:38:08 -0500226
227 return sel_netif_sid_slow(ifindex, sid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228}
229
Paul Mooree8bfdb92008-01-29 08:38:08 -0500230/**
231 * sel_netif_kill - Remove an entry from the network interface table
232 * @ifindex: the network interface
233 *
234 * Description:
235 * This function removes the entry matching @ifindex from the network interface
236 * table if it exists.
237 *
238 */
239static void sel_netif_kill(int ifindex)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240{
241 struct sel_netif *netif;
242
243 spin_lock_bh(&sel_netif_lock);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500244 netif = sel_netif_find(ifindex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 if (netif)
246 sel_netif_destroy(netif);
247 spin_unlock_bh(&sel_netif_lock);
248}
249
Paul Mooree8bfdb92008-01-29 08:38:08 -0500250/**
251 * sel_netif_flush - Flush the entire network interface table
252 *
253 * Description:
254 * Remove all entries from the network interface table.
255 *
256 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257static void sel_netif_flush(void)
258{
259 int idx;
Paul Mooree8bfdb92008-01-29 08:38:08 -0500260 struct sel_netif *netif;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
262 spin_lock_bh(&sel_netif_lock);
Paul Mooree8bfdb92008-01-29 08:38:08 -0500263 for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 list_for_each_entry(netif, &sel_netif_hash[idx], list)
265 sel_netif_destroy(netif);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 spin_unlock_bh(&sel_netif_lock);
267}
268
269static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
270 u16 class, u32 perms, u32 *retained)
271{
272 if (event == AVC_CALLBACK_RESET) {
273 sel_netif_flush();
274 synchronize_net();
275 }
276 return 0;
277}
278
279static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
280 unsigned long event, void *ptr)
281{
282 struct net_device *dev = ptr;
283
YOSHIFUJI Hideakic346dca2008-03-25 21:47:49 +0900284 if (dev_net(dev) != &init_net)
Eric W. Biedermane9dc8652007-09-12 13:02:17 +0200285 return NOTIFY_DONE;
286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 if (event == NETDEV_DOWN)
Paul Mooree8bfdb92008-01-29 08:38:08 -0500288 sel_netif_kill(dev->ifindex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
290 return NOTIFY_DONE;
291}
292
293static struct notifier_block sel_netif_netdev_notifier = {
294 .notifier_call = sel_netif_netdev_notifier_handler,
295};
296
297static __init int sel_netif_init(void)
298{
Paul Mooree8bfdb92008-01-29 08:38:08 -0500299 int i, err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300
301 if (!selinux_enabled)
Paul Mooree8bfdb92008-01-29 08:38:08 -0500302 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
304 for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
305 INIT_LIST_HEAD(&sel_netif_hash[i]);
306
307 register_netdevice_notifier(&sel_netif_netdev_notifier);
308
309 err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET,
310 SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
311 if (err)
312 panic("avc_add_callback() failed, error %d\n", err);
313
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 return err;
315}
316
317__initcall(sel_netif_init);
318