Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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> | |
e8bfdb9d | 10 | * Copyright (C) 2007 Hewlett-Packard Development Company, L.P. |
338366cb | 11 | * Paul Moore <paul.moore@hp.com> |
1da177e4 LT |
12 | * |
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> | |
e9dc8653 | 25 | #include <net/net_namespace.h> |
1da177e4 LT |
26 | |
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 | ||
338366cb | 34 | struct sel_netif { |
1da177e4 LT |
35 | struct list_head list; |
36 | struct netif_security_struct nsec; | |
37 | struct rcu_head rcu_head; | |
38 | }; | |
39 | ||
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]; | |
44 | ||
e8bfdb9d PM |
45 | /** |
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 | */ | |
54 | static inline u32 sel_netif_hashfn(int ifindex) | |
1da177e4 | 55 | { |
e8bfdb9d | 56 | return (ifindex & (SEL_NETIF_HASH_SIZE - 1)); |
1da177e4 LT |
57 | } |
58 | ||
e8bfdb9d PM |
59 | /** |
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 | * | |
1da177e4 | 67 | */ |
e8bfdb9d | 68 | static inline struct sel_netif *sel_netif_find(int ifindex) |
1da177e4 | 69 | { |
e8bfdb9d PM |
70 | int idx = sel_netif_hashfn(ifindex); |
71 | struct sel_netif *netif; | |
1da177e4 | 72 | |
e8bfdb9d PM |
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)) | |
1da177e4 | 77 | return netif; |
e8bfdb9d | 78 | |
1da177e4 LT |
79 | return NULL; |
80 | } | |
81 | ||
e8bfdb9d PM |
82 | /** |
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 | */ | |
1da177e4 LT |
91 | static int sel_netif_insert(struct sel_netif *netif) |
92 | { | |
e8bfdb9d | 93 | int idx; |
338366cb | 94 | |
e8bfdb9d PM |
95 | if (sel_netif_total >= SEL_NETIF_HASH_MAX) |
96 | return -ENOSPC; | |
338366cb | 97 | |
e8bfdb9d | 98 | idx = sel_netif_hashfn(netif->nsec.ifindex); |
1da177e4 LT |
99 | list_add_rcu(&netif->list, &sel_netif_hash[idx]); |
100 | sel_netif_total++; | |
e8bfdb9d PM |
101 | |
102 | return 0; | |
1da177e4 LT |
103 | } |
104 | ||
e8bfdb9d PM |
105 | /** |
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 | */ | |
1da177e4 LT |
115 | static void sel_netif_free(struct rcu_head *p) |
116 | { | |
117 | struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head); | |
1da177e4 LT |
118 | kfree(netif); |
119 | } | |
120 | ||
e8bfdb9d PM |
121 | /** |
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 | */ | |
1da177e4 LT |
129 | static void sel_netif_destroy(struct sel_netif *netif) |
130 | { | |
1da177e4 LT |
131 | list_del_rcu(&netif->list); |
132 | sel_netif_total--; | |
133 | call_rcu(&netif->rcu_head, sel_netif_free); | |
134 | } | |
135 | ||
e8bfdb9d PM |
136 | /** |
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 | */ | |
148 | static int sel_netif_sid_slow(int ifindex, u32 *sid) | |
1da177e4 LT |
149 | { |
150 | int ret; | |
e8bfdb9d PM |
151 | struct sel_netif *netif; |
152 | struct sel_netif *new = NULL; | |
153 | struct net_device *dev; | |
1da177e4 | 154 | |
e8bfdb9d PM |
155 | /* NOTE: we always use init's network namespace since we don't |
156 | * currently support containers */ | |
1da177e4 | 157 | |
e8bfdb9d | 158 | dev = dev_get_by_index(&init_net, ifindex); |
71f1cb05 PM |
159 | if (unlikely(dev == NULL)) { |
160 | printk(KERN_WARNING | |
161 | "SELinux: failure in sel_netif_sid_slow()," | |
162 | " invalid network interface (%d)\n", ifindex); | |
e8bfdb9d | 163 | return -ENOENT; |
71f1cb05 | 164 | } |
1da177e4 | 165 | |
1da177e4 | 166 | spin_lock_bh(&sel_netif_lock); |
e8bfdb9d PM |
167 | netif = sel_netif_find(ifindex); |
168 | if (netif != NULL) { | |
169 | *sid = netif->nsec.sid; | |
170 | ret = 0; | |
1da177e4 LT |
171 | goto out; |
172 | } | |
e8bfdb9d PM |
173 | new = kzalloc(sizeof(*new), GFP_ATOMIC); |
174 | if (new == NULL) { | |
175 | ret = -ENOMEM; | |
1da177e4 LT |
176 | goto out; |
177 | } | |
e8bfdb9d PM |
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; | |
1da177e4 | 186 | |
1da177e4 | 187 | out: |
e8bfdb9d PM |
188 | spin_unlock_bh(&sel_netif_lock); |
189 | dev_put(dev); | |
71f1cb05 PM |
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); | |
e8bfdb9d | 195 | kfree(new); |
71f1cb05 | 196 | } |
1da177e4 LT |
197 | return ret; |
198 | } | |
199 | ||
e8bfdb9d PM |
200 | /** |
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 | */ | |
213 | int sel_netif_sid(int ifindex, u32 *sid) | |
1da177e4 | 214 | { |
1da177e4 LT |
215 | struct sel_netif *netif; |
216 | ||
217 | rcu_read_lock(); | |
e8bfdb9d PM |
218 | netif = sel_netif_find(ifindex); |
219 | if (likely(netif != NULL)) { | |
220 | *sid = netif->nsec.sid; | |
1da177e4 | 221 | rcu_read_unlock(); |
e8bfdb9d | 222 | return 0; |
1da177e4 | 223 | } |
1da177e4 | 224 | rcu_read_unlock(); |
e8bfdb9d PM |
225 | |
226 | return sel_netif_sid_slow(ifindex, sid); | |
1da177e4 LT |
227 | } |
228 | ||
e8bfdb9d PM |
229 | /** |
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 | */ | |
238 | static void sel_netif_kill(int ifindex) | |
1da177e4 LT |
239 | { |
240 | struct sel_netif *netif; | |
241 | ||
61844250 | 242 | rcu_read_lock(); |
1da177e4 | 243 | spin_lock_bh(&sel_netif_lock); |
e8bfdb9d | 244 | netif = sel_netif_find(ifindex); |
1da177e4 LT |
245 | if (netif) |
246 | sel_netif_destroy(netif); | |
247 | spin_unlock_bh(&sel_netif_lock); | |
61844250 | 248 | rcu_read_unlock(); |
1da177e4 LT |
249 | } |
250 | ||
e8bfdb9d PM |
251 | /** |
252 | * sel_netif_flush - Flush the entire network interface table | |
253 | * | |
254 | * Description: | |
255 | * Remove all entries from the network interface table. | |
256 | * | |
257 | */ | |
1da177e4 LT |
258 | static void sel_netif_flush(void) |
259 | { | |
260 | int idx; | |
e8bfdb9d | 261 | struct sel_netif *netif; |
1da177e4 LT |
262 | |
263 | spin_lock_bh(&sel_netif_lock); | |
e8bfdb9d | 264 | for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) |
1da177e4 LT |
265 | list_for_each_entry(netif, &sel_netif_hash[idx], list) |
266 | sel_netif_destroy(netif); | |
1da177e4 LT |
267 | spin_unlock_bh(&sel_netif_lock); |
268 | } | |
269 | ||
270 | static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid, | |
338366cb | 271 | u16 class, u32 perms, u32 *retained) |
1da177e4 LT |
272 | { |
273 | if (event == AVC_CALLBACK_RESET) { | |
274 | sel_netif_flush(); | |
275 | synchronize_net(); | |
276 | } | |
277 | return 0; | |
278 | } | |
279 | ||
280 | static int sel_netif_netdev_notifier_handler(struct notifier_block *this, | |
338366cb | 281 | unsigned long event, void *ptr) |
1da177e4 LT |
282 | { |
283 | struct net_device *dev = ptr; | |
284 | ||
c346dca1 | 285 | if (dev_net(dev) != &init_net) |
e9dc8653 EB |
286 | return NOTIFY_DONE; |
287 | ||
1da177e4 | 288 | if (event == NETDEV_DOWN) |
e8bfdb9d | 289 | sel_netif_kill(dev->ifindex); |
1da177e4 LT |
290 | |
291 | return NOTIFY_DONE; | |
292 | } | |
293 | ||
294 | static struct notifier_block sel_netif_netdev_notifier = { | |
295 | .notifier_call = sel_netif_netdev_notifier_handler, | |
296 | }; | |
297 | ||
298 | static __init int sel_netif_init(void) | |
299 | { | |
e8bfdb9d | 300 | int i, err; |
338366cb | 301 | |
1da177e4 | 302 | if (!selinux_enabled) |
e8bfdb9d | 303 | return 0; |
1da177e4 LT |
304 | |
305 | for (i = 0; i < SEL_NETIF_HASH_SIZE; i++) | |
306 | INIT_LIST_HEAD(&sel_netif_hash[i]); | |
307 | ||
308 | register_netdevice_notifier(&sel_netif_netdev_notifier); | |
338366cb | 309 | |
1da177e4 | 310 | err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET, |
338366cb | 311 | SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0); |
1da177e4 LT |
312 | if (err) |
313 | panic("avc_add_callback() failed, error %d\n", err); | |
314 | ||
1da177e4 LT |
315 | return err; |
316 | } | |
317 | ||
318 | __initcall(sel_netif_init); | |
319 |