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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * Network interface table. | |
4 | * | |
5 | * Network interfaces (devices) do not have a security field, so we | |
6 | * maintain a table associating each interface with a SID. | |
7 | * | |
8 | * Author: James Morris <jmorris@redhat.com> | |
9 | * | |
10 | * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
e8bfdb9d | 11 | * Copyright (C) 2007 Hewlett-Packard Development Company, L.P. |
82c21bfa | 12 | * Paul Moore <paul@paul-moore.com> |
1da177e4 LT |
13 | */ |
14 | #include <linux/init.h> | |
15 | #include <linux/types.h> | |
5a0e3ad6 | 16 | #include <linux/slab.h> |
1da177e4 LT |
17 | #include <linux/stddef.h> |
18 | #include <linux/kernel.h> | |
19 | #include <linux/list.h> | |
20 | #include <linux/notifier.h> | |
21 | #include <linux/netdevice.h> | |
22 | #include <linux/rcupdate.h> | |
e9dc8653 | 23 | #include <net/net_namespace.h> |
1da177e4 LT |
24 | |
25 | #include "security.h" | |
26 | #include "objsec.h" | |
27 | #include "netif.h" | |
28 | ||
29 | #define SEL_NETIF_HASH_SIZE 64 | |
30 | #define SEL_NETIF_HASH_MAX 1024 | |
31 | ||
338366cb | 32 | struct sel_netif { |
1da177e4 LT |
33 | struct list_head list; |
34 | struct netif_security_struct nsec; | |
35 | struct rcu_head rcu_head; | |
36 | }; | |
37 | ||
38 | static u32 sel_netif_total; | |
1da177e4 LT |
39 | static DEFINE_SPINLOCK(sel_netif_lock); |
40 | static struct list_head sel_netif_hash[SEL_NETIF_HASH_SIZE]; | |
41 | ||
e8bfdb9d PM |
42 | /** |
43 | * sel_netif_hashfn - Hashing function for the interface table | |
cbe0d6e8 | 44 | * @ns: the network namespace |
e8bfdb9d PM |
45 | * @ifindex: the network interface |
46 | * | |
47 | * Description: | |
48 | * This is the hashing function for the network interface table, it returns the | |
49 | * bucket number for the given interface. | |
50 | * | |
51 | */ | |
cbe0d6e8 | 52 | static inline u32 sel_netif_hashfn(const struct net *ns, int ifindex) |
1da177e4 | 53 | { |
cbe0d6e8 | 54 | return (((uintptr_t)ns + ifindex) & (SEL_NETIF_HASH_SIZE - 1)); |
1da177e4 LT |
55 | } |
56 | ||
e8bfdb9d PM |
57 | /** |
58 | * sel_netif_find - Search for an interface record | |
cbe0d6e8 | 59 | * @ns: the network namespace |
e8bfdb9d PM |
60 | * @ifindex: the network interface |
61 | * | |
62 | * Description: | |
63 | * Search the network interface table and return the record matching @ifindex. | |
64 | * If an entry can not be found in the table return NULL. | |
65 | * | |
1da177e4 | 66 | */ |
cbe0d6e8 PM |
67 | static inline struct sel_netif *sel_netif_find(const struct net *ns, |
68 | int ifindex) | |
1da177e4 | 69 | { |
cbe0d6e8 | 70 | int idx = sel_netif_hashfn(ns, ifindex); |
e8bfdb9d | 71 | struct sel_netif *netif; |
1da177e4 | 72 | |
e8bfdb9d | 73 | list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list) |
cbe0d6e8 PM |
74 | if (net_eq(netif->nsec.ns, ns) && |
75 | netif->nsec.ifindex == ifindex) | |
1da177e4 | 76 | return netif; |
e8bfdb9d | 77 | |
1da177e4 LT |
78 | return NULL; |
79 | } | |
80 | ||
e8bfdb9d PM |
81 | /** |
82 | * sel_netif_insert - Insert a new interface into the table | |
83 | * @netif: the new interface record | |
84 | * | |
85 | * Description: | |
86 | * Add a new interface record to the network interface hash table. Returns | |
87 | * zero on success, negative values on failure. | |
88 | * | |
89 | */ | |
1da177e4 LT |
90 | static int sel_netif_insert(struct sel_netif *netif) |
91 | { | |
e8bfdb9d | 92 | int idx; |
338366cb | 93 | |
e8bfdb9d PM |
94 | if (sel_netif_total >= SEL_NETIF_HASH_MAX) |
95 | return -ENOSPC; | |
338366cb | 96 | |
cbe0d6e8 | 97 | idx = sel_netif_hashfn(netif->nsec.ns, netif->nsec.ifindex); |
1da177e4 LT |
98 | list_add_rcu(&netif->list, &sel_netif_hash[idx]); |
99 | sel_netif_total++; | |
e8bfdb9d PM |
100 | |
101 | return 0; | |
1da177e4 LT |
102 | } |
103 | ||
e8bfdb9d PM |
104 | /** |
105 | * sel_netif_destroy - Remove an interface record from the table | |
106 | * @netif: the existing interface record | |
107 | * | |
108 | * Description: | |
109 | * Remove an existing interface record from the network interface table. | |
110 | * | |
111 | */ | |
1da177e4 LT |
112 | static void sel_netif_destroy(struct sel_netif *netif) |
113 | { | |
1da177e4 LT |
114 | list_del_rcu(&netif->list); |
115 | sel_netif_total--; | |
690273fc | 116 | kfree_rcu(netif, rcu_head); |
1da177e4 LT |
117 | } |
118 | ||
e8bfdb9d PM |
119 | /** |
120 | * sel_netif_sid_slow - Lookup the SID of a network interface using the policy | |
cbe0d6e8 | 121 | * @ns: the network namespace |
e8bfdb9d PM |
122 | * @ifindex: the network interface |
123 | * @sid: interface SID | |
124 | * | |
125 | * Description: | |
2c3d8dfe | 126 | * This function determines the SID of a network interface by querying the |
e8bfdb9d PM |
127 | * security policy. The result is added to the network interface table to |
128 | * speedup future queries. Returns zero on success, negative values on | |
129 | * failure. | |
130 | * | |
131 | */ | |
cbe0d6e8 | 132 | static int sel_netif_sid_slow(struct net *ns, int ifindex, u32 *sid) |
1da177e4 | 133 | { |
9b80c363 | 134 | int ret = 0; |
e8bfdb9d | 135 | struct sel_netif *netif; |
9b80c363 | 136 | struct sel_netif *new; |
e8bfdb9d | 137 | struct net_device *dev; |
1da177e4 | 138 | |
e8bfdb9d PM |
139 | /* NOTE: we always use init's network namespace since we don't |
140 | * currently support containers */ | |
1da177e4 | 141 | |
cbe0d6e8 | 142 | dev = dev_get_by_index(ns, ifindex); |
71f1cb05 | 143 | if (unlikely(dev == NULL)) { |
0d3a1154 | 144 | pr_warn("SELinux: failure in %s(), invalid network interface (%d)\n", |
145 | __func__, ifindex); | |
e8bfdb9d | 146 | return -ENOENT; |
71f1cb05 | 147 | } |
1da177e4 | 148 | |
1da177e4 | 149 | spin_lock_bh(&sel_netif_lock); |
cbe0d6e8 | 150 | netif = sel_netif_find(ns, ifindex); |
e8bfdb9d PM |
151 | if (netif != NULL) { |
152 | *sid = netif->nsec.sid; | |
1da177e4 LT |
153 | goto out; |
154 | } | |
9b80c363 PM |
155 | |
156 | ret = security_netif_sid(&selinux_state, dev->name, sid); | |
e8bfdb9d PM |
157 | if (ret != 0) |
158 | goto out; | |
9b80c363 PM |
159 | new = kzalloc(sizeof(*new), GFP_ATOMIC); |
160 | if (new) { | |
161 | new->nsec.ns = ns; | |
162 | new->nsec.ifindex = ifindex; | |
163 | new->nsec.sid = *sid; | |
164 | if (sel_netif_insert(new)) | |
165 | kfree(new); | |
166 | } | |
1da177e4 | 167 | |
1da177e4 | 168 | out: |
e8bfdb9d PM |
169 | spin_unlock_bh(&sel_netif_lock); |
170 | dev_put(dev); | |
9b80c363 | 171 | if (unlikely(ret)) |
0d3a1154 | 172 | pr_warn("SELinux: failure in %s(), unable to determine network interface label (%d)\n", |
173 | __func__, ifindex); | |
1da177e4 LT |
174 | return ret; |
175 | } | |
176 | ||
e8bfdb9d PM |
177 | /** |
178 | * sel_netif_sid - Lookup the SID of a network interface | |
cbe0d6e8 | 179 | * @ns: the network namespace |
e8bfdb9d PM |
180 | * @ifindex: the network interface |
181 | * @sid: interface SID | |
182 | * | |
183 | * Description: | |
184 | * This function determines the SID of a network interface using the fastest | |
185 | * method possible. First the interface table is queried, but if an entry | |
186 | * can't be found then the policy is queried and the result is added to the | |
187 | * table to speedup future queries. Returns zero on success, negative values | |
188 | * on failure. | |
189 | * | |
190 | */ | |
cbe0d6e8 | 191 | int sel_netif_sid(struct net *ns, int ifindex, u32 *sid) |
1da177e4 | 192 | { |
1da177e4 LT |
193 | struct sel_netif *netif; |
194 | ||
195 | rcu_read_lock(); | |
cbe0d6e8 | 196 | netif = sel_netif_find(ns, ifindex); |
e8bfdb9d PM |
197 | if (likely(netif != NULL)) { |
198 | *sid = netif->nsec.sid; | |
1da177e4 | 199 | rcu_read_unlock(); |
e8bfdb9d | 200 | return 0; |
1da177e4 | 201 | } |
1da177e4 | 202 | rcu_read_unlock(); |
e8bfdb9d | 203 | |
cbe0d6e8 | 204 | return sel_netif_sid_slow(ns, ifindex, sid); |
1da177e4 LT |
205 | } |
206 | ||
e8bfdb9d PM |
207 | /** |
208 | * sel_netif_kill - Remove an entry from the network interface table | |
cbe0d6e8 | 209 | * @ns: the network namespace |
e8bfdb9d PM |
210 | * @ifindex: the network interface |
211 | * | |
212 | * Description: | |
213 | * This function removes the entry matching @ifindex from the network interface | |
214 | * table if it exists. | |
215 | * | |
216 | */ | |
cbe0d6e8 | 217 | static void sel_netif_kill(const struct net *ns, int ifindex) |
1da177e4 LT |
218 | { |
219 | struct sel_netif *netif; | |
220 | ||
61844250 | 221 | rcu_read_lock(); |
1da177e4 | 222 | spin_lock_bh(&sel_netif_lock); |
cbe0d6e8 | 223 | netif = sel_netif_find(ns, ifindex); |
1da177e4 LT |
224 | if (netif) |
225 | sel_netif_destroy(netif); | |
226 | spin_unlock_bh(&sel_netif_lock); | |
61844250 | 227 | rcu_read_unlock(); |
1da177e4 LT |
228 | } |
229 | ||
e8bfdb9d PM |
230 | /** |
231 | * sel_netif_flush - Flush the entire network interface table | |
232 | * | |
233 | * Description: | |
234 | * Remove all entries from the network interface table. | |
235 | * | |
236 | */ | |
615e51fd | 237 | void sel_netif_flush(void) |
1da177e4 LT |
238 | { |
239 | int idx; | |
e8bfdb9d | 240 | struct sel_netif *netif; |
1da177e4 LT |
241 | |
242 | spin_lock_bh(&sel_netif_lock); | |
e8bfdb9d | 243 | for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) |
1da177e4 LT |
244 | list_for_each_entry(netif, &sel_netif_hash[idx], list) |
245 | sel_netif_destroy(netif); | |
1da177e4 LT |
246 | spin_unlock_bh(&sel_netif_lock); |
247 | } | |
248 | ||
1da177e4 | 249 | static int sel_netif_netdev_notifier_handler(struct notifier_block *this, |
338366cb | 250 | unsigned long event, void *ptr) |
1da177e4 | 251 | { |
351638e7 | 252 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); |
1da177e4 LT |
253 | |
254 | if (event == NETDEV_DOWN) | |
cbe0d6e8 | 255 | sel_netif_kill(dev_net(dev), dev->ifindex); |
1da177e4 LT |
256 | |
257 | return NOTIFY_DONE; | |
258 | } | |
259 | ||
260 | static struct notifier_block sel_netif_netdev_notifier = { | |
261 | .notifier_call = sel_netif_netdev_notifier_handler, | |
262 | }; | |
263 | ||
264 | static __init int sel_netif_init(void) | |
265 | { | |
942ba364 | 266 | int i; |
338366cb | 267 | |
6c5a682e | 268 | if (!selinux_enabled_boot) |
e8bfdb9d | 269 | return 0; |
1da177e4 LT |
270 | |
271 | for (i = 0; i < SEL_NETIF_HASH_SIZE; i++) | |
272 | INIT_LIST_HEAD(&sel_netif_hash[i]); | |
273 | ||
274 | register_netdevice_notifier(&sel_netif_netdev_notifier); | |
338366cb | 275 | |
942ba364 | 276 | return 0; |
1da177e4 LT |
277 | } |
278 | ||
279 | __initcall(sel_netif_init); | |
280 |