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> | |
5a0e3ad6 | 19 | #include <linux/slab.h> |
1da177e4 LT |
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> | |
e9dc8653 | 26 | #include <net/net_namespace.h> |
1da177e4 LT |
27 | |
28 | #include "security.h" | |
29 | #include "objsec.h" | |
30 | #include "netif.h" | |
31 | ||
32 | #define SEL_NETIF_HASH_SIZE 64 | |
33 | #define SEL_NETIF_HASH_MAX 1024 | |
34 | ||
338366cb | 35 | struct sel_netif { |
1da177e4 LT |
36 | struct list_head list; |
37 | struct netif_security_struct nsec; | |
38 | struct rcu_head rcu_head; | |
39 | }; | |
40 | ||
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]; | |
45 | ||
e8bfdb9d PM |
46 | /** |
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 | */ | |
55 | static inline u32 sel_netif_hashfn(int ifindex) | |
1da177e4 | 56 | { |
e8bfdb9d | 57 | return (ifindex & (SEL_NETIF_HASH_SIZE - 1)); |
1da177e4 LT |
58 | } |
59 | ||
e8bfdb9d PM |
60 | /** |
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 | * | |
1da177e4 | 68 | */ |
e8bfdb9d | 69 | static inline struct sel_netif *sel_netif_find(int ifindex) |
1da177e4 | 70 | { |
e8bfdb9d PM |
71 | int idx = sel_netif_hashfn(ifindex); |
72 | struct sel_netif *netif; | |
1da177e4 | 73 | |
e8bfdb9d PM |
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)) | |
1da177e4 | 78 | return netif; |
e8bfdb9d | 79 | |
1da177e4 LT |
80 | return NULL; |
81 | } | |
82 | ||
e8bfdb9d PM |
83 | /** |
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 | */ | |
1da177e4 LT |
92 | static int sel_netif_insert(struct sel_netif *netif) |
93 | { | |
e8bfdb9d | 94 | int idx; |
338366cb | 95 | |
e8bfdb9d PM |
96 | if (sel_netif_total >= SEL_NETIF_HASH_MAX) |
97 | return -ENOSPC; | |
338366cb | 98 | |
e8bfdb9d | 99 | idx = sel_netif_hashfn(netif->nsec.ifindex); |
1da177e4 LT |
100 | list_add_rcu(&netif->list, &sel_netif_hash[idx]); |
101 | sel_netif_total++; | |
e8bfdb9d PM |
102 | |
103 | return 0; | |
1da177e4 LT |
104 | } |
105 | ||
e8bfdb9d PM |
106 | /** |
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 | */ | |
1da177e4 LT |
116 | static void sel_netif_free(struct rcu_head *p) |
117 | { | |
118 | struct sel_netif *netif = container_of(p, struct sel_netif, rcu_head); | |
1da177e4 LT |
119 | kfree(netif); |
120 | } | |
121 | ||
e8bfdb9d PM |
122 | /** |
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 | */ | |
1da177e4 LT |
130 | static void sel_netif_destroy(struct sel_netif *netif) |
131 | { | |
1da177e4 LT |
132 | list_del_rcu(&netif->list); |
133 | sel_netif_total--; | |
134 | call_rcu(&netif->rcu_head, sel_netif_free); | |
135 | } | |
136 | ||
e8bfdb9d PM |
137 | /** |
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 | */ | |
149 | static int sel_netif_sid_slow(int ifindex, u32 *sid) | |
1da177e4 LT |
150 | { |
151 | int ret; | |
e8bfdb9d PM |
152 | struct sel_netif *netif; |
153 | struct sel_netif *new = NULL; | |
154 | struct net_device *dev; | |
1da177e4 | 155 | |
e8bfdb9d PM |
156 | /* NOTE: we always use init's network namespace since we don't |
157 | * currently support containers */ | |
1da177e4 | 158 | |
e8bfdb9d | 159 | dev = dev_get_by_index(&init_net, ifindex); |
71f1cb05 PM |
160 | if (unlikely(dev == NULL)) { |
161 | printk(KERN_WARNING | |
162 | "SELinux: failure in sel_netif_sid_slow()," | |
163 | " invalid network interface (%d)\n", ifindex); | |
e8bfdb9d | 164 | return -ENOENT; |
71f1cb05 | 165 | } |
1da177e4 | 166 | |
1da177e4 | 167 | spin_lock_bh(&sel_netif_lock); |
e8bfdb9d PM |
168 | netif = sel_netif_find(ifindex); |
169 | if (netif != NULL) { | |
170 | *sid = netif->nsec.sid; | |
171 | ret = 0; | |
1da177e4 LT |
172 | goto out; |
173 | } | |
e8bfdb9d PM |
174 | new = kzalloc(sizeof(*new), GFP_ATOMIC); |
175 | if (new == NULL) { | |
176 | ret = -ENOMEM; | |
1da177e4 LT |
177 | goto out; |
178 | } | |
e8bfdb9d PM |
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; | |
1da177e4 | 187 | |
1da177e4 | 188 | out: |
e8bfdb9d PM |
189 | spin_unlock_bh(&sel_netif_lock); |
190 | dev_put(dev); | |
71f1cb05 PM |
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); | |
e8bfdb9d | 196 | kfree(new); |
71f1cb05 | 197 | } |
1da177e4 LT |
198 | return ret; |
199 | } | |
200 | ||
e8bfdb9d PM |
201 | /** |
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 | */ | |
214 | int sel_netif_sid(int ifindex, u32 *sid) | |
1da177e4 | 215 | { |
1da177e4 LT |
216 | struct sel_netif *netif; |
217 | ||
218 | rcu_read_lock(); | |
e8bfdb9d PM |
219 | netif = sel_netif_find(ifindex); |
220 | if (likely(netif != NULL)) { | |
221 | *sid = netif->nsec.sid; | |
1da177e4 | 222 | rcu_read_unlock(); |
e8bfdb9d | 223 | return 0; |
1da177e4 | 224 | } |
1da177e4 | 225 | rcu_read_unlock(); |
e8bfdb9d PM |
226 | |
227 | return sel_netif_sid_slow(ifindex, sid); | |
1da177e4 LT |
228 | } |
229 | ||
e8bfdb9d PM |
230 | /** |
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 | */ | |
239 | static void sel_netif_kill(int ifindex) | |
1da177e4 LT |
240 | { |
241 | struct sel_netif *netif; | |
242 | ||
61844250 | 243 | rcu_read_lock(); |
1da177e4 | 244 | spin_lock_bh(&sel_netif_lock); |
e8bfdb9d | 245 | netif = sel_netif_find(ifindex); |
1da177e4 LT |
246 | if (netif) |
247 | sel_netif_destroy(netif); | |
248 | spin_unlock_bh(&sel_netif_lock); | |
61844250 | 249 | rcu_read_unlock(); |
1da177e4 LT |
250 | } |
251 | ||
e8bfdb9d PM |
252 | /** |
253 | * sel_netif_flush - Flush the entire network interface table | |
254 | * | |
255 | * Description: | |
256 | * Remove all entries from the network interface table. | |
257 | * | |
258 | */ | |
1da177e4 LT |
259 | static void sel_netif_flush(void) |
260 | { | |
261 | int idx; | |
e8bfdb9d | 262 | struct sel_netif *netif; |
1da177e4 LT |
263 | |
264 | spin_lock_bh(&sel_netif_lock); | |
e8bfdb9d | 265 | for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) |
1da177e4 LT |
266 | list_for_each_entry(netif, &sel_netif_hash[idx], list) |
267 | sel_netif_destroy(netif); | |
1da177e4 LT |
268 | spin_unlock_bh(&sel_netif_lock); |
269 | } | |
270 | ||
271 | static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid, | |
338366cb | 272 | u16 class, u32 perms, u32 *retained) |
1da177e4 LT |
273 | { |
274 | if (event == AVC_CALLBACK_RESET) { | |
275 | sel_netif_flush(); | |
276 | synchronize_net(); | |
277 | } | |
278 | return 0; | |
279 | } | |
280 | ||
281 | static int sel_netif_netdev_notifier_handler(struct notifier_block *this, | |
338366cb | 282 | unsigned long event, void *ptr) |
1da177e4 LT |
283 | { |
284 | struct net_device *dev = ptr; | |
285 | ||
c346dca1 | 286 | if (dev_net(dev) != &init_net) |
e9dc8653 EB |
287 | return NOTIFY_DONE; |
288 | ||
1da177e4 | 289 | if (event == NETDEV_DOWN) |
e8bfdb9d | 290 | sel_netif_kill(dev->ifindex); |
1da177e4 LT |
291 | |
292 | return NOTIFY_DONE; | |
293 | } | |
294 | ||
295 | static struct notifier_block sel_netif_netdev_notifier = { | |
296 | .notifier_call = sel_netif_netdev_notifier_handler, | |
297 | }; | |
298 | ||
299 | static __init int sel_netif_init(void) | |
300 | { | |
e8bfdb9d | 301 | int i, err; |
338366cb | 302 | |
1da177e4 | 303 | if (!selinux_enabled) |
e8bfdb9d | 304 | return 0; |
1da177e4 LT |
305 | |
306 | for (i = 0; i < SEL_NETIF_HASH_SIZE; i++) | |
307 | INIT_LIST_HEAD(&sel_netif_hash[i]); | |
308 | ||
309 | register_netdevice_notifier(&sel_netif_netdev_notifier); | |
338366cb | 310 | |
1da177e4 | 311 | err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET, |
338366cb | 312 | SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0); |
1da177e4 LT |
313 | if (err) |
314 | panic("avc_add_callback() failed, error %d\n", err); | |
315 | ||
1da177e4 LT |
316 | return err; |
317 | } | |
318 | ||
319 | __initcall(sel_netif_init); | |
320 |