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. |
82c21bfa | 11 | * Paul Moore <paul@paul-moore.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 | |
cbe0d6e8 | 48 | * @ns: the network namespace |
e8bfdb9d PM |
49 | * @ifindex: the network interface |
50 | * | |
51 | * Description: | |
52 | * This is the hashing function for the network interface table, it returns the | |
53 | * bucket number for the given interface. | |
54 | * | |
55 | */ | |
cbe0d6e8 | 56 | static inline u32 sel_netif_hashfn(const struct net *ns, int ifindex) |
1da177e4 | 57 | { |
cbe0d6e8 | 58 | return (((uintptr_t)ns + ifindex) & (SEL_NETIF_HASH_SIZE - 1)); |
1da177e4 LT |
59 | } |
60 | ||
e8bfdb9d PM |
61 | /** |
62 | * sel_netif_find - Search for an interface record | |
cbe0d6e8 | 63 | * @ns: the network namespace |
e8bfdb9d PM |
64 | * @ifindex: the network interface |
65 | * | |
66 | * Description: | |
67 | * Search the network interface table and return the record matching @ifindex. | |
68 | * If an entry can not be found in the table return NULL. | |
69 | * | |
1da177e4 | 70 | */ |
cbe0d6e8 PM |
71 | static inline struct sel_netif *sel_netif_find(const struct net *ns, |
72 | int ifindex) | |
1da177e4 | 73 | { |
cbe0d6e8 | 74 | int idx = sel_netif_hashfn(ns, ifindex); |
e8bfdb9d | 75 | struct sel_netif *netif; |
1da177e4 | 76 | |
e8bfdb9d | 77 | list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list) |
cbe0d6e8 PM |
78 | if (net_eq(netif->nsec.ns, ns) && |
79 | netif->nsec.ifindex == ifindex) | |
1da177e4 | 80 | return netif; |
e8bfdb9d | 81 | |
1da177e4 LT |
82 | return NULL; |
83 | } | |
84 | ||
e8bfdb9d PM |
85 | /** |
86 | * sel_netif_insert - Insert a new interface into the table | |
87 | * @netif: the new interface record | |
88 | * | |
89 | * Description: | |
90 | * Add a new interface record to the network interface hash table. Returns | |
91 | * zero on success, negative values on failure. | |
92 | * | |
93 | */ | |
1da177e4 LT |
94 | static int sel_netif_insert(struct sel_netif *netif) |
95 | { | |
e8bfdb9d | 96 | int idx; |
338366cb | 97 | |
e8bfdb9d PM |
98 | if (sel_netif_total >= SEL_NETIF_HASH_MAX) |
99 | return -ENOSPC; | |
338366cb | 100 | |
cbe0d6e8 | 101 | idx = sel_netif_hashfn(netif->nsec.ns, netif->nsec.ifindex); |
1da177e4 LT |
102 | list_add_rcu(&netif->list, &sel_netif_hash[idx]); |
103 | sel_netif_total++; | |
e8bfdb9d PM |
104 | |
105 | return 0; | |
1da177e4 LT |
106 | } |
107 | ||
e8bfdb9d PM |
108 | /** |
109 | * sel_netif_destroy - Remove an interface record from the table | |
110 | * @netif: the existing interface record | |
111 | * | |
112 | * Description: | |
113 | * Remove an existing interface record from the network interface table. | |
114 | * | |
115 | */ | |
1da177e4 LT |
116 | static void sel_netif_destroy(struct sel_netif *netif) |
117 | { | |
1da177e4 LT |
118 | list_del_rcu(&netif->list); |
119 | sel_netif_total--; | |
690273fc | 120 | kfree_rcu(netif, rcu_head); |
1da177e4 LT |
121 | } |
122 | ||
e8bfdb9d PM |
123 | /** |
124 | * sel_netif_sid_slow - Lookup the SID of a network interface using the policy | |
cbe0d6e8 | 125 | * @ns: the network namespace |
e8bfdb9d PM |
126 | * @ifindex: the network interface |
127 | * @sid: interface SID | |
128 | * | |
129 | * Description: | |
130 | * This function determines the SID of a network interface by quering the | |
131 | * security policy. The result is added to the network interface table to | |
132 | * speedup future queries. Returns zero on success, negative values on | |
133 | * failure. | |
134 | * | |
135 | */ | |
cbe0d6e8 | 136 | static int sel_netif_sid_slow(struct net *ns, int ifindex, u32 *sid) |
1da177e4 LT |
137 | { |
138 | int ret; | |
e8bfdb9d PM |
139 | struct sel_netif *netif; |
140 | struct sel_netif *new = NULL; | |
141 | struct net_device *dev; | |
1da177e4 | 142 | |
e8bfdb9d PM |
143 | /* NOTE: we always use init's network namespace since we don't |
144 | * currently support containers */ | |
1da177e4 | 145 | |
cbe0d6e8 | 146 | dev = dev_get_by_index(ns, ifindex); |
71f1cb05 PM |
147 | if (unlikely(dev == NULL)) { |
148 | printk(KERN_WARNING | |
149 | "SELinux: failure in sel_netif_sid_slow()," | |
150 | " invalid network interface (%d)\n", ifindex); | |
e8bfdb9d | 151 | return -ENOENT; |
71f1cb05 | 152 | } |
1da177e4 | 153 | |
1da177e4 | 154 | spin_lock_bh(&sel_netif_lock); |
cbe0d6e8 | 155 | netif = sel_netif_find(ns, ifindex); |
e8bfdb9d PM |
156 | if (netif != NULL) { |
157 | *sid = netif->nsec.sid; | |
158 | ret = 0; | |
1da177e4 LT |
159 | goto out; |
160 | } | |
e8bfdb9d PM |
161 | new = kzalloc(sizeof(*new), GFP_ATOMIC); |
162 | if (new == NULL) { | |
163 | ret = -ENOMEM; | |
1da177e4 LT |
164 | goto out; |
165 | } | |
e8bfdb9d PM |
166 | ret = security_netif_sid(dev->name, &new->nsec.sid); |
167 | if (ret != 0) | |
168 | goto out; | |
cbe0d6e8 | 169 | new->nsec.ns = ns; |
e8bfdb9d PM |
170 | new->nsec.ifindex = ifindex; |
171 | ret = sel_netif_insert(new); | |
172 | if (ret != 0) | |
173 | goto out; | |
174 | *sid = new->nsec.sid; | |
1da177e4 | 175 | |
1da177e4 | 176 | out: |
e8bfdb9d PM |
177 | spin_unlock_bh(&sel_netif_lock); |
178 | dev_put(dev); | |
71f1cb05 PM |
179 | if (unlikely(ret)) { |
180 | printk(KERN_WARNING | |
181 | "SELinux: failure in sel_netif_sid_slow()," | |
182 | " unable to determine network interface label (%d)\n", | |
183 | ifindex); | |
e8bfdb9d | 184 | kfree(new); |
71f1cb05 | 185 | } |
1da177e4 LT |
186 | return ret; |
187 | } | |
188 | ||
e8bfdb9d PM |
189 | /** |
190 | * sel_netif_sid - Lookup the SID of a network interface | |
cbe0d6e8 | 191 | * @ns: the network namespace |
e8bfdb9d PM |
192 | * @ifindex: the network interface |
193 | * @sid: interface SID | |
194 | * | |
195 | * Description: | |
196 | * This function determines the SID of a network interface using the fastest | |
197 | * method possible. First the interface table is queried, but if an entry | |
198 | * can't be found then the policy is queried and the result is added to the | |
199 | * table to speedup future queries. Returns zero on success, negative values | |
200 | * on failure. | |
201 | * | |
202 | */ | |
cbe0d6e8 | 203 | int sel_netif_sid(struct net *ns, int ifindex, u32 *sid) |
1da177e4 | 204 | { |
1da177e4 LT |
205 | struct sel_netif *netif; |
206 | ||
207 | rcu_read_lock(); | |
cbe0d6e8 | 208 | netif = sel_netif_find(ns, ifindex); |
e8bfdb9d PM |
209 | if (likely(netif != NULL)) { |
210 | *sid = netif->nsec.sid; | |
1da177e4 | 211 | rcu_read_unlock(); |
e8bfdb9d | 212 | return 0; |
1da177e4 | 213 | } |
1da177e4 | 214 | rcu_read_unlock(); |
e8bfdb9d | 215 | |
cbe0d6e8 | 216 | return sel_netif_sid_slow(ns, ifindex, sid); |
1da177e4 LT |
217 | } |
218 | ||
e8bfdb9d PM |
219 | /** |
220 | * sel_netif_kill - Remove an entry from the network interface table | |
cbe0d6e8 | 221 | * @ns: the network namespace |
e8bfdb9d PM |
222 | * @ifindex: the network interface |
223 | * | |
224 | * Description: | |
225 | * This function removes the entry matching @ifindex from the network interface | |
226 | * table if it exists. | |
227 | * | |
228 | */ | |
cbe0d6e8 | 229 | static void sel_netif_kill(const struct net *ns, int ifindex) |
1da177e4 LT |
230 | { |
231 | struct sel_netif *netif; | |
232 | ||
61844250 | 233 | rcu_read_lock(); |
1da177e4 | 234 | spin_lock_bh(&sel_netif_lock); |
cbe0d6e8 | 235 | netif = sel_netif_find(ns, ifindex); |
1da177e4 LT |
236 | if (netif) |
237 | sel_netif_destroy(netif); | |
238 | spin_unlock_bh(&sel_netif_lock); | |
61844250 | 239 | rcu_read_unlock(); |
1da177e4 LT |
240 | } |
241 | ||
e8bfdb9d PM |
242 | /** |
243 | * sel_netif_flush - Flush the entire network interface table | |
244 | * | |
245 | * Description: | |
246 | * Remove all entries from the network interface table. | |
247 | * | |
248 | */ | |
615e51fd | 249 | void sel_netif_flush(void) |
1da177e4 LT |
250 | { |
251 | int idx; | |
e8bfdb9d | 252 | struct sel_netif *netif; |
1da177e4 LT |
253 | |
254 | spin_lock_bh(&sel_netif_lock); | |
e8bfdb9d | 255 | for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) |
1da177e4 LT |
256 | list_for_each_entry(netif, &sel_netif_hash[idx], list) |
257 | sel_netif_destroy(netif); | |
1da177e4 LT |
258 | spin_unlock_bh(&sel_netif_lock); |
259 | } | |
260 | ||
1da177e4 | 261 | static int sel_netif_netdev_notifier_handler(struct notifier_block *this, |
338366cb | 262 | unsigned long event, void *ptr) |
1da177e4 | 263 | { |
351638e7 | 264 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); |
1da177e4 LT |
265 | |
266 | if (event == NETDEV_DOWN) | |
cbe0d6e8 | 267 | sel_netif_kill(dev_net(dev), dev->ifindex); |
1da177e4 LT |
268 | |
269 | return NOTIFY_DONE; | |
270 | } | |
271 | ||
272 | static struct notifier_block sel_netif_netdev_notifier = { | |
273 | .notifier_call = sel_netif_netdev_notifier_handler, | |
274 | }; | |
275 | ||
276 | static __init int sel_netif_init(void) | |
277 | { | |
942ba364 | 278 | int i; |
338366cb | 279 | |
1da177e4 | 280 | if (!selinux_enabled) |
e8bfdb9d | 281 | return 0; |
1da177e4 LT |
282 | |
283 | for (i = 0; i < SEL_NETIF_HASH_SIZE; i++) | |
284 | INIT_LIST_HEAD(&sel_netif_hash[i]); | |
285 | ||
286 | register_netdevice_notifier(&sel_netif_netdev_notifier); | |
338366cb | 287 | |
942ba364 | 288 | return 0; |
1da177e4 LT |
289 | } |
290 | ||
291 | __initcall(sel_netif_init); | |
292 |