Loading...
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>
10 * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
11 * Paul Moore <paul@paul-moore.com>
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/slab.h>
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>
26#include <net/net_namespace.h>
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
35struct sel_netif {
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
46/**
47 * sel_netif_hashfn - Hashing function for the interface table
48 * @ns: the network namespace
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 */
56static inline u32 sel_netif_hashfn(const struct net *ns, int ifindex)
57{
58 return (((uintptr_t)ns + ifindex) & (SEL_NETIF_HASH_SIZE - 1));
59}
60
61/**
62 * sel_netif_find - Search for an interface record
63 * @ns: the network namespace
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 *
70 */
71static inline struct sel_netif *sel_netif_find(const struct net *ns,
72 int ifindex)
73{
74 int idx = sel_netif_hashfn(ns, ifindex);
75 struct sel_netif *netif;
76
77 list_for_each_entry_rcu(netif, &sel_netif_hash[idx], list)
78 if (net_eq(netif->nsec.ns, ns) &&
79 netif->nsec.ifindex == ifindex)
80 return netif;
81
82 return NULL;
83}
84
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 */
94static int sel_netif_insert(struct sel_netif *netif)
95{
96 int idx;
97
98 if (sel_netif_total >= SEL_NETIF_HASH_MAX)
99 return -ENOSPC;
100
101 idx = sel_netif_hashfn(netif->nsec.ns, netif->nsec.ifindex);
102 list_add_rcu(&netif->list, &sel_netif_hash[idx]);
103 sel_netif_total++;
104
105 return 0;
106}
107
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 */
116static void sel_netif_destroy(struct sel_netif *netif)
117{
118 list_del_rcu(&netif->list);
119 sel_netif_total--;
120 kfree_rcu(netif, rcu_head);
121}
122
123/**
124 * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
125 * @ns: the network namespace
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 */
136static int sel_netif_sid_slow(struct net *ns, int ifindex, u32 *sid)
137{
138 int ret;
139 struct sel_netif *netif;
140 struct sel_netif *new = NULL;
141 struct net_device *dev;
142
143 /* NOTE: we always use init's network namespace since we don't
144 * currently support containers */
145
146 dev = dev_get_by_index(ns, ifindex);
147 if (unlikely(dev == NULL)) {
148 printk(KERN_WARNING
149 "SELinux: failure in sel_netif_sid_slow(),"
150 " invalid network interface (%d)\n", ifindex);
151 return -ENOENT;
152 }
153
154 spin_lock_bh(&sel_netif_lock);
155 netif = sel_netif_find(ns, ifindex);
156 if (netif != NULL) {
157 *sid = netif->nsec.sid;
158 ret = 0;
159 goto out;
160 }
161 new = kzalloc(sizeof(*new), GFP_ATOMIC);
162 if (new == NULL) {
163 ret = -ENOMEM;
164 goto out;
165 }
166 ret = security_netif_sid(dev->name, &new->nsec.sid);
167 if (ret != 0)
168 goto out;
169 new->nsec.ns = ns;
170 new->nsec.ifindex = ifindex;
171 ret = sel_netif_insert(new);
172 if (ret != 0)
173 goto out;
174 *sid = new->nsec.sid;
175
176out:
177 spin_unlock_bh(&sel_netif_lock);
178 dev_put(dev);
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);
184 kfree(new);
185 }
186 return ret;
187}
188
189/**
190 * sel_netif_sid - Lookup the SID of a network interface
191 * @ns: the network namespace
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 */
203int sel_netif_sid(struct net *ns, int ifindex, u32 *sid)
204{
205 struct sel_netif *netif;
206
207 rcu_read_lock();
208 netif = sel_netif_find(ns, ifindex);
209 if (likely(netif != NULL)) {
210 *sid = netif->nsec.sid;
211 rcu_read_unlock();
212 return 0;
213 }
214 rcu_read_unlock();
215
216 return sel_netif_sid_slow(ns, ifindex, sid);
217}
218
219/**
220 * sel_netif_kill - Remove an entry from the network interface table
221 * @ns: the network namespace
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 */
229static void sel_netif_kill(const struct net *ns, int ifindex)
230{
231 struct sel_netif *netif;
232
233 rcu_read_lock();
234 spin_lock_bh(&sel_netif_lock);
235 netif = sel_netif_find(ns, ifindex);
236 if (netif)
237 sel_netif_destroy(netif);
238 spin_unlock_bh(&sel_netif_lock);
239 rcu_read_unlock();
240}
241
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 */
249void sel_netif_flush(void)
250{
251 int idx;
252 struct sel_netif *netif;
253
254 spin_lock_bh(&sel_netif_lock);
255 for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
256 list_for_each_entry(netif, &sel_netif_hash[idx], list)
257 sel_netif_destroy(netif);
258 spin_unlock_bh(&sel_netif_lock);
259}
260
261static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
262 unsigned long event, void *ptr)
263{
264 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
265
266 if (event == NETDEV_DOWN)
267 sel_netif_kill(dev_net(dev), dev->ifindex);
268
269 return NOTIFY_DONE;
270}
271
272static struct notifier_block sel_netif_netdev_notifier = {
273 .notifier_call = sel_netif_netdev_notifier_handler,
274};
275
276static __init int sel_netif_init(void)
277{
278 int i;
279
280 if (!selinux_enabled)
281 return 0;
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);
287
288 return 0;
289}
290
291__initcall(sel_netif_init);
292
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>
10 * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
11 * Paul Moore <paul@paul-moore.com>
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/slab.h>
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>
26#include <net/net_namespace.h>
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
35struct sel_netif {
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
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 */
55static inline u32 sel_netif_hashfn(int ifindex)
56{
57 return (ifindex & (SEL_NETIF_HASH_SIZE - 1));
58}
59
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 *
68 */
69static inline struct sel_netif *sel_netif_find(int ifindex)
70{
71 int idx = sel_netif_hashfn(ifindex);
72 struct sel_netif *netif;
73
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))
78 return netif;
79
80 return NULL;
81}
82
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 */
92static int sel_netif_insert(struct sel_netif *netif)
93{
94 int idx;
95
96 if (sel_netif_total >= SEL_NETIF_HASH_MAX)
97 return -ENOSPC;
98
99 idx = sel_netif_hashfn(netif->nsec.ifindex);
100 list_add_rcu(&netif->list, &sel_netif_hash[idx]);
101 sel_netif_total++;
102
103 return 0;
104}
105
106/**
107 * sel_netif_destroy - Remove an interface record from the table
108 * @netif: the existing interface record
109 *
110 * Description:
111 * Remove an existing interface record from the network interface table.
112 *
113 */
114static void sel_netif_destroy(struct sel_netif *netif)
115{
116 list_del_rcu(&netif->list);
117 sel_netif_total--;
118 kfree_rcu(netif, rcu_head);
119}
120
121/**
122 * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
123 * @ifindex: the network interface
124 * @sid: interface SID
125 *
126 * Description:
127 * This function determines the SID of a network interface by quering the
128 * security policy. The result is added to the network interface table to
129 * speedup future queries. Returns zero on success, negative values on
130 * failure.
131 *
132 */
133static int sel_netif_sid_slow(int ifindex, u32 *sid)
134{
135 int ret;
136 struct sel_netif *netif;
137 struct sel_netif *new = NULL;
138 struct net_device *dev;
139
140 /* NOTE: we always use init's network namespace since we don't
141 * currently support containers */
142
143 dev = dev_get_by_index(&init_net, ifindex);
144 if (unlikely(dev == NULL)) {
145 printk(KERN_WARNING
146 "SELinux: failure in sel_netif_sid_slow(),"
147 " invalid network interface (%d)\n", ifindex);
148 return -ENOENT;
149 }
150
151 spin_lock_bh(&sel_netif_lock);
152 netif = sel_netif_find(ifindex);
153 if (netif != NULL) {
154 *sid = netif->nsec.sid;
155 ret = 0;
156 goto out;
157 }
158 new = kzalloc(sizeof(*new), GFP_ATOMIC);
159 if (new == NULL) {
160 ret = -ENOMEM;
161 goto out;
162 }
163 ret = security_netif_sid(dev->name, &new->nsec.sid);
164 if (ret != 0)
165 goto out;
166 new->nsec.ifindex = ifindex;
167 ret = sel_netif_insert(new);
168 if (ret != 0)
169 goto out;
170 *sid = new->nsec.sid;
171
172out:
173 spin_unlock_bh(&sel_netif_lock);
174 dev_put(dev);
175 if (unlikely(ret)) {
176 printk(KERN_WARNING
177 "SELinux: failure in sel_netif_sid_slow(),"
178 " unable to determine network interface label (%d)\n",
179 ifindex);
180 kfree(new);
181 }
182 return ret;
183}
184
185/**
186 * sel_netif_sid - Lookup the SID of a network interface
187 * @ifindex: the network interface
188 * @sid: interface SID
189 *
190 * Description:
191 * This function determines the SID of a network interface using the fastest
192 * method possible. First the interface table is queried, but if an entry
193 * can't be found then the policy is queried and the result is added to the
194 * table to speedup future queries. Returns zero on success, negative values
195 * on failure.
196 *
197 */
198int sel_netif_sid(int ifindex, u32 *sid)
199{
200 struct sel_netif *netif;
201
202 rcu_read_lock();
203 netif = sel_netif_find(ifindex);
204 if (likely(netif != NULL)) {
205 *sid = netif->nsec.sid;
206 rcu_read_unlock();
207 return 0;
208 }
209 rcu_read_unlock();
210
211 return sel_netif_sid_slow(ifindex, sid);
212}
213
214/**
215 * sel_netif_kill - Remove an entry from the network interface table
216 * @ifindex: the network interface
217 *
218 * Description:
219 * This function removes the entry matching @ifindex from the network interface
220 * table if it exists.
221 *
222 */
223static void sel_netif_kill(int ifindex)
224{
225 struct sel_netif *netif;
226
227 rcu_read_lock();
228 spin_lock_bh(&sel_netif_lock);
229 netif = sel_netif_find(ifindex);
230 if (netif)
231 sel_netif_destroy(netif);
232 spin_unlock_bh(&sel_netif_lock);
233 rcu_read_unlock();
234}
235
236/**
237 * sel_netif_flush - Flush the entire network interface table
238 *
239 * Description:
240 * Remove all entries from the network interface table.
241 *
242 */
243static void sel_netif_flush(void)
244{
245 int idx;
246 struct sel_netif *netif;
247
248 spin_lock_bh(&sel_netif_lock);
249 for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++)
250 list_for_each_entry(netif, &sel_netif_hash[idx], list)
251 sel_netif_destroy(netif);
252 spin_unlock_bh(&sel_netif_lock);
253}
254
255static int sel_netif_avc_callback(u32 event)
256{
257 if (event == AVC_CALLBACK_RESET) {
258 sel_netif_flush();
259 synchronize_net();
260 }
261 return 0;
262}
263
264static int sel_netif_netdev_notifier_handler(struct notifier_block *this,
265 unsigned long event, void *ptr)
266{
267 struct net_device *dev = ptr;
268
269 if (dev_net(dev) != &init_net)
270 return NOTIFY_DONE;
271
272 if (event == NETDEV_DOWN)
273 sel_netif_kill(dev->ifindex);
274
275 return NOTIFY_DONE;
276}
277
278static struct notifier_block sel_netif_netdev_notifier = {
279 .notifier_call = sel_netif_netdev_notifier_handler,
280};
281
282static __init int sel_netif_init(void)
283{
284 int i, err;
285
286 if (!selinux_enabled)
287 return 0;
288
289 for (i = 0; i < SEL_NETIF_HASH_SIZE; i++)
290 INIT_LIST_HEAD(&sel_netif_hash[i]);
291
292 register_netdevice_notifier(&sel_netif_netdev_notifier);
293
294 err = avc_add_callback(sel_netif_avc_callback, AVC_CALLBACK_RESET);
295 if (err)
296 panic("avc_add_callback() failed, error %d\n", err);
297
298 return err;
299}
300
301__initcall(sel_netif_init);
302