blob: c5454c0477c346e4d814f5ff209feba86e5b86ad [file] [log] [blame]
Paul Moore224dfbd2008-01-29 08:38:13 -05001/*
2 * Network node table
3 *
4 * SELinux must keep a mapping of network nodes to labels/SIDs. This
5 * mapping is maintained as part of the normal policy but a fast cache is
6 * needed to reduce the lookup overhead since most of these queries happen on
7 * a per-packet basis.
8 *
Paul Moore82c21bf2011-08-01 11:10:33 +00009 * Author: Paul Moore <paul@paul-moore.com>
Paul Moore224dfbd2008-01-29 08:38:13 -050010 *
11 * This code is heavily based on the "netif" concept originally developed by
12 * James Morris <jmorris@redhat.com>
13 * (see security/selinux/netif.c for more information)
14 *
15 */
16
17/*
18 * (c) Copyright Hewlett-Packard Development Company, L.P., 2007
19 *
20 * This program is free software: you can redistribute it and/or modify
21 * it under the terms of version 2 of the GNU General Public License as
22 * published by the Free Software Foundation.
23 *
24 * This program is distributed in the hope that it will be useful,
25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27 * GNU General Public License for more details.
28 *
29 */
30
31#include <linux/types.h>
32#include <linux/rcupdate.h>
33#include <linux/list.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090034#include <linux/slab.h>
Paul Moore224dfbd2008-01-29 08:38:13 -050035#include <linux/spinlock.h>
36#include <linux/in.h>
37#include <linux/in6.h>
38#include <linux/ip.h>
39#include <linux/ipv6.h>
40#include <net/ip.h>
41#include <net/ipv6.h>
Paul Moore224dfbd2008-01-29 08:38:13 -050042
Paul Moorea639e7ca2008-04-25 15:03:34 -040043#include "netnode.h"
Paul Moore224dfbd2008-01-29 08:38:13 -050044#include "objsec.h"
45
46#define SEL_NETNODE_HASH_SIZE 256
47#define SEL_NETNODE_HASH_BKT_LIMIT 16
48
Paul Moorea639e7ca2008-04-25 15:03:34 -040049struct sel_netnode_bkt {
50 unsigned int size;
51 struct list_head list;
52};
53
Paul Moore224dfbd2008-01-29 08:38:13 -050054struct sel_netnode {
55 struct netnode_security_struct nsec;
56
57 struct list_head list;
58 struct rcu_head rcu;
59};
60
61/* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
62 * for this is that I suspect most users will not make heavy use of both
63 * address families at the same time so one table will usually end up wasted,
64 * if this becomes a problem we can always add a hash table for each address
65 * family later */
66
67static LIST_HEAD(sel_netnode_list);
68static DEFINE_SPINLOCK(sel_netnode_lock);
Paul Moorea639e7ca2008-04-25 15:03:34 -040069static struct sel_netnode_bkt sel_netnode_hash[SEL_NETNODE_HASH_SIZE];
Paul Moore224dfbd2008-01-29 08:38:13 -050070
71/**
Paul Moore224dfbd2008-01-29 08:38:13 -050072 * sel_netnode_hashfn_ipv4 - IPv4 hashing function for the node table
73 * @addr: IPv4 address
74 *
75 * Description:
76 * This is the IPv4 hashing function for the node interface table, it returns
77 * the bucket number for the given IP address.
78 *
79 */
Paul Moorea639e7ca2008-04-25 15:03:34 -040080static unsigned int sel_netnode_hashfn_ipv4(__be32 addr)
Paul Moore224dfbd2008-01-29 08:38:13 -050081{
82 /* at some point we should determine if the mismatch in byte order
83 * affects the hash function dramatically */
84 return (addr & (SEL_NETNODE_HASH_SIZE - 1));
85}
86
87/**
88 * sel_netnode_hashfn_ipv6 - IPv6 hashing function for the node table
89 * @addr: IPv6 address
90 *
91 * Description:
92 * This is the IPv6 hashing function for the node interface table, it returns
93 * the bucket number for the given IP address.
94 *
95 */
Paul Moorea639e7ca2008-04-25 15:03:34 -040096static unsigned int sel_netnode_hashfn_ipv6(const struct in6_addr *addr)
Paul Moore224dfbd2008-01-29 08:38:13 -050097{
98 /* just hash the least significant 32 bits to keep things fast (they
99 * are the most likely to be different anyway), we can revisit this
100 * later if needed */
101 return (addr->s6_addr32[3] & (SEL_NETNODE_HASH_SIZE - 1));
102}
103
104/**
105 * sel_netnode_find - Search for a node record
106 * @addr: IP address
107 * @family: address family
108 *
109 * Description:
110 * Search the network node table and return the record matching @addr. If an
111 * entry can not be found in the table return NULL.
112 *
113 */
114static struct sel_netnode *sel_netnode_find(const void *addr, u16 family)
115{
Paul Moorea639e7ca2008-04-25 15:03:34 -0400116 unsigned int idx;
Paul Moore224dfbd2008-01-29 08:38:13 -0500117 struct sel_netnode *node;
118
119 switch (family) {
120 case PF_INET:
121 idx = sel_netnode_hashfn_ipv4(*(__be32 *)addr);
122 break;
123 case PF_INET6:
124 idx = sel_netnode_hashfn_ipv6(addr);
125 break;
126 default:
127 BUG();
Eric Parisa35c6c82011-04-20 10:21:28 -0400128 return NULL;
Paul Moore224dfbd2008-01-29 08:38:13 -0500129 }
130
Paul Moorea639e7ca2008-04-25 15:03:34 -0400131 list_for_each_entry_rcu(node, &sel_netnode_hash[idx].list, list)
Paul Moore224dfbd2008-01-29 08:38:13 -0500132 if (node->nsec.family == family)
133 switch (family) {
134 case PF_INET:
135 if (node->nsec.addr.ipv4 == *(__be32 *)addr)
136 return node;
137 break;
138 case PF_INET6:
139 if (ipv6_addr_equal(&node->nsec.addr.ipv6,
140 addr))
141 return node;
142 break;
143 }
144
145 return NULL;
146}
147
148/**
149 * sel_netnode_insert - Insert a new node into the table
150 * @node: the new node record
151 *
152 * Description:
Paul Moorea639e7ca2008-04-25 15:03:34 -0400153 * Add a new node record to the network address hash table.
Paul Moore224dfbd2008-01-29 08:38:13 -0500154 *
155 */
Paul Moorea639e7ca2008-04-25 15:03:34 -0400156static void sel_netnode_insert(struct sel_netnode *node)
Paul Moore224dfbd2008-01-29 08:38:13 -0500157{
Paul Moorea639e7ca2008-04-25 15:03:34 -0400158 unsigned int idx;
Paul Moore224dfbd2008-01-29 08:38:13 -0500159
160 switch (node->nsec.family) {
161 case PF_INET:
162 idx = sel_netnode_hashfn_ipv4(node->nsec.addr.ipv4);
163 break;
164 case PF_INET6:
165 idx = sel_netnode_hashfn_ipv6(&node->nsec.addr.ipv6);
166 break;
167 default:
168 BUG();
169 }
Paul Moorea639e7ca2008-04-25 15:03:34 -0400170
Paul Moore224dfbd2008-01-29 08:38:13 -0500171 /* we need to impose a limit on the growth of the hash table so check
172 * this bucket to make sure it is within the specified bounds */
Paul Moorea639e7ca2008-04-25 15:03:34 -0400173 list_add_rcu(&node->list, &sel_netnode_hash[idx].list);
174 if (sel_netnode_hash[idx].size == SEL_NETNODE_HASH_BKT_LIMIT) {
175 struct sel_netnode *tail;
176 tail = list_entry(
Dave Jones88a693b2012-11-08 16:09:27 -0800177 rcu_dereference_protected(sel_netnode_hash[idx].list.prev,
178 lockdep_is_held(&sel_netnode_lock)),
Paul Moorea639e7ca2008-04-25 15:03:34 -0400179 struct sel_netnode, list);
180 list_del_rcu(&tail->list);
Lai Jiangshan9801c602011-03-18 12:05:22 +0800181 kfree_rcu(tail, rcu);
Paul Moorea639e7ca2008-04-25 15:03:34 -0400182 } else
183 sel_netnode_hash[idx].size++;
Paul Moore224dfbd2008-01-29 08:38:13 -0500184}
185
186/**
187 * sel_netnode_sid_slow - Lookup the SID of a network address using the policy
188 * @addr: the IP address
189 * @family: the address family
190 * @sid: node SID
191 *
192 * Description:
193 * This function determines the SID of a network address by quering the
194 * security policy. The result is added to the network address table to
195 * speedup future queries. Returns zero on success, negative values on
196 * failure.
197 *
198 */
199static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid)
200{
Paul Moorea639e7ca2008-04-25 15:03:34 -0400201 int ret = -ENOMEM;
Paul Moore224dfbd2008-01-29 08:38:13 -0500202 struct sel_netnode *node;
203 struct sel_netnode *new = NULL;
204
205 spin_lock_bh(&sel_netnode_lock);
206 node = sel_netnode_find(addr, family);
207 if (node != NULL) {
208 *sid = node->nsec.sid;
Paul Moorea639e7ca2008-04-25 15:03:34 -0400209 spin_unlock_bh(&sel_netnode_lock);
210 return 0;
Paul Moore224dfbd2008-01-29 08:38:13 -0500211 }
212 new = kzalloc(sizeof(*new), GFP_ATOMIC);
Paul Moorea639e7ca2008-04-25 15:03:34 -0400213 if (new == NULL)
Paul Moore224dfbd2008-01-29 08:38:13 -0500214 goto out;
Paul Moore224dfbd2008-01-29 08:38:13 -0500215 switch (family) {
216 case PF_INET:
217 ret = security_node_sid(PF_INET,
Paul Moorea639e7ca2008-04-25 15:03:34 -0400218 addr, sizeof(struct in_addr), sid);
Paul Moore224dfbd2008-01-29 08:38:13 -0500219 new->nsec.addr.ipv4 = *(__be32 *)addr;
220 break;
221 case PF_INET6:
222 ret = security_node_sid(PF_INET6,
Paul Moorea639e7ca2008-04-25 15:03:34 -0400223 addr, sizeof(struct in6_addr), sid);
Alexey Dobriyan4e3fd7a2011-11-21 03:39:03 +0000224 new->nsec.addr.ipv6 = *(struct in6_addr *)addr;
Paul Moore224dfbd2008-01-29 08:38:13 -0500225 break;
226 default:
227 BUG();
228 }
229 if (ret != 0)
230 goto out;
Paul Moorea639e7ca2008-04-25 15:03:34 -0400231
Paul Moore224dfbd2008-01-29 08:38:13 -0500232 new->nsec.family = family;
Paul Moorea639e7ca2008-04-25 15:03:34 -0400233 new->nsec.sid = *sid;
234 sel_netnode_insert(new);
Paul Moore224dfbd2008-01-29 08:38:13 -0500235
236out:
237 spin_unlock_bh(&sel_netnode_lock);
Paul Moore71f1cb02008-01-29 08:51:16 -0500238 if (unlikely(ret)) {
239 printk(KERN_WARNING
240 "SELinux: failure in sel_netnode_sid_slow(),"
241 " unable to determine network node label\n");
Paul Moore224dfbd2008-01-29 08:38:13 -0500242 kfree(new);
Paul Moore71f1cb02008-01-29 08:51:16 -0500243 }
Paul Moore224dfbd2008-01-29 08:38:13 -0500244 return ret;
245}
246
247/**
248 * sel_netnode_sid - Lookup the SID of a network address
249 * @addr: the IP address
250 * @family: the address family
251 * @sid: node SID
252 *
253 * Description:
254 * This function determines the SID of a network address using the fastest
255 * method possible. First the address table is queried, but if an entry
256 * can't be found then the policy is queried and the result is added to the
257 * table to speedup future queries. Returns zero on success, negative values
258 * on failure.
259 *
260 */
261int sel_netnode_sid(void *addr, u16 family, u32 *sid)
262{
263 struct sel_netnode *node;
264
265 rcu_read_lock();
266 node = sel_netnode_find(addr, family);
267 if (node != NULL) {
268 *sid = node->nsec.sid;
269 rcu_read_unlock();
270 return 0;
271 }
272 rcu_read_unlock();
273
274 return sel_netnode_sid_slow(addr, family, sid);
275}
276
277/**
278 * sel_netnode_flush - Flush the entire network address table
279 *
280 * Description:
281 * Remove all entries from the network address table.
282 *
283 */
284static void sel_netnode_flush(void)
285{
Paul Moorea639e7ca2008-04-25 15:03:34 -0400286 unsigned int idx;
287 struct sel_netnode *node, *node_tmp;
Paul Moore224dfbd2008-01-29 08:38:13 -0500288
289 spin_lock_bh(&sel_netnode_lock);
Paul Moorea639e7ca2008-04-25 15:03:34 -0400290 for (idx = 0; idx < SEL_NETNODE_HASH_SIZE; idx++) {
291 list_for_each_entry_safe(node, node_tmp,
292 &sel_netnode_hash[idx].list, list) {
293 list_del_rcu(&node->list);
Lai Jiangshan9801c602011-03-18 12:05:22 +0800294 kfree_rcu(node, rcu);
Paul Moorea639e7ca2008-04-25 15:03:34 -0400295 }
296 sel_netnode_hash[idx].size = 0;
297 }
Paul Moore224dfbd2008-01-29 08:38:13 -0500298 spin_unlock_bh(&sel_netnode_lock);
299}
300
Wanlong Gao562c99f2012-03-07 22:17:14 +0800301static int sel_netnode_avc_callback(u32 event)
Paul Moore224dfbd2008-01-29 08:38:13 -0500302{
303 if (event == AVC_CALLBACK_RESET) {
304 sel_netnode_flush();
305 synchronize_net();
306 }
307 return 0;
308}
309
310static __init int sel_netnode_init(void)
311{
312 int iter;
313 int ret;
314
315 if (!selinux_enabled)
316 return 0;
317
Paul Moorea639e7ca2008-04-25 15:03:34 -0400318 for (iter = 0; iter < SEL_NETNODE_HASH_SIZE; iter++) {
319 INIT_LIST_HEAD(&sel_netnode_hash[iter].list);
320 sel_netnode_hash[iter].size = 0;
321 }
Paul Moore224dfbd2008-01-29 08:38:13 -0500322
Wanlong Gao562c99f2012-03-07 22:17:14 +0800323 ret = avc_add_callback(sel_netnode_avc_callback, AVC_CALLBACK_RESET);
Paul Moore224dfbd2008-01-29 08:38:13 -0500324 if (ret != 0)
325 panic("avc_add_callback() failed, error %d\n", ret);
326
327 return ret;
328}
329
330__initcall(sel_netnode_init);