2 * Network interface table.
4 * Network interfaces (devices) do not have a security field, so we
5 * maintain a table associating each interface with a SID.
7 * Author: James Morris <jmorris@redhat.com>
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.moore@hp.com>
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.
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>
25 #include <net/net_namespace.h>
31 #define SEL_NETIF_HASH_SIZE 64
32 #define SEL_NETIF_HASH_MAX 1024
36 struct list_head list
;
37 struct netif_security_struct nsec
;
38 struct rcu_head rcu_head
;
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
];
47 * sel_netif_hashfn - Hashing function for the interface table
48 * @ifindex: the network interface
51 * This is the hashing function for the network interface table, it returns the
52 * bucket number for the given interface.
55 static inline u32
sel_netif_hashfn(int ifindex
)
57 return (ifindex
& (SEL_NETIF_HASH_SIZE
- 1));
61 * sel_netif_find - Search for an interface record
62 * @ifindex: the network interface
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.
69 static inline struct sel_netif
*sel_netif_find(int ifindex
)
71 int idx
= sel_netif_hashfn(ifindex
);
72 struct sel_netif
*netif
;
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
))
84 * sel_netif_insert - Insert a new interface into the table
85 * @netif: the new interface record
88 * Add a new interface record to the network interface hash table. Returns
89 * zero on success, negative values on failure.
92 static int sel_netif_insert(struct sel_netif
*netif
)
96 if (sel_netif_total
>= SEL_NETIF_HASH_MAX
)
99 idx
= sel_netif_hashfn(netif
->nsec
.ifindex
);
100 list_add_rcu(&netif
->list
, &sel_netif_hash
[idx
]);
107 * sel_netif_free - Frees an interface entry
108 * @p: the entry's RCU field
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
116 static void sel_netif_free(struct rcu_head
*p
)
118 struct sel_netif
*netif
= container_of(p
, struct sel_netif
, rcu_head
);
123 * sel_netif_destroy - Remove an interface record from the table
124 * @netif: the existing interface record
127 * Remove an existing interface record from the network interface table.
130 static void sel_netif_destroy(struct sel_netif
*netif
)
132 list_del_rcu(&netif
->list
);
134 call_rcu(&netif
->rcu_head
, sel_netif_free
);
138 * sel_netif_sid_slow - Lookup the SID of a network interface using the policy
139 * @ifindex: the network interface
140 * @sid: interface SID
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
149 static int sel_netif_sid_slow(int ifindex
, u32
*sid
)
152 struct sel_netif
*netif
;
153 struct sel_netif
*new = NULL
;
154 struct net_device
*dev
;
156 /* NOTE: we always use init's network namespace since we don't
157 * currently support containers */
159 dev
= dev_get_by_index(&init_net
, ifindex
);
163 spin_lock_bh(&sel_netif_lock
);
164 netif
= sel_netif_find(ifindex
);
166 *sid
= netif
->nsec
.sid
;
170 new = kzalloc(sizeof(*new), GFP_ATOMIC
);
175 ret
= security_netif_sid(dev
->name
, &new->nsec
.sid
);
178 new->nsec
.ifindex
= ifindex
;
179 ret
= sel_netif_insert(new);
182 *sid
= new->nsec
.sid
;
185 spin_unlock_bh(&sel_netif_lock
);
193 * sel_netif_sid - Lookup the SID of a network interface
194 * @ifindex: the network interface
195 * @sid: interface SID
198 * This function determines the SID of a network interface using the fastest
199 * method possible. First the interface table is queried, but if an entry
200 * can't be found then the policy is queried and the result is added to the
201 * table to speedup future queries. Returns zero on success, negative values
205 int sel_netif_sid(int ifindex
, u32
*sid
)
207 struct sel_netif
*netif
;
210 netif
= sel_netif_find(ifindex
);
211 if (likely(netif
!= NULL
)) {
212 *sid
= netif
->nsec
.sid
;
218 return sel_netif_sid_slow(ifindex
, sid
);
222 * sel_netif_kill - Remove an entry from the network interface table
223 * @ifindex: the network interface
226 * This function removes the entry matching @ifindex from the network interface
227 * table if it exists.
230 static void sel_netif_kill(int ifindex
)
232 struct sel_netif
*netif
;
234 spin_lock_bh(&sel_netif_lock
);
235 netif
= sel_netif_find(ifindex
);
237 sel_netif_destroy(netif
);
238 spin_unlock_bh(&sel_netif_lock
);
242 * sel_netif_flush - Flush the entire network interface table
245 * Remove all entries from the network interface table.
248 static void sel_netif_flush(void)
251 struct sel_netif
*netif
;
253 spin_lock_bh(&sel_netif_lock
);
254 for (idx
= 0; idx
< SEL_NETIF_HASH_SIZE
; idx
++)
255 list_for_each_entry(netif
, &sel_netif_hash
[idx
], list
)
256 sel_netif_destroy(netif
);
257 spin_unlock_bh(&sel_netif_lock
);
260 static int sel_netif_avc_callback(u32 event
, u32 ssid
, u32 tsid
,
261 u16
class, u32 perms
, u32
*retained
)
263 if (event
== AVC_CALLBACK_RESET
) {
270 static int sel_netif_netdev_notifier_handler(struct notifier_block
*this,
271 unsigned long event
, void *ptr
)
273 struct net_device
*dev
= ptr
;
275 if (dev
->nd_net
!= &init_net
)
278 if (event
== NETDEV_DOWN
)
279 sel_netif_kill(dev
->ifindex
);
284 static struct notifier_block sel_netif_netdev_notifier
= {
285 .notifier_call
= sel_netif_netdev_notifier_handler
,
288 static __init
int sel_netif_init(void)
292 if (!selinux_enabled
)
295 for (i
= 0; i
< SEL_NETIF_HASH_SIZE
; i
++)
296 INIT_LIST_HEAD(&sel_netif_hash
[i
]);
298 register_netdevice_notifier(&sel_netif_netdev_notifier
);
300 err
= avc_add_callback(sel_netif_avc_callback
, AVC_CALLBACK_RESET
,
301 SECSID_NULL
, SECSID_NULL
, SECCLASS_NULL
, 0);
303 panic("avc_add_callback() failed, error %d\n", err
);
308 __initcall(sel_netif_init
);