blob: 3bf46abaa688cbb7735f1d47cf3d33348f9b019a [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 Parisa35c6c832011-04-20 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(
177 rcu_dereference(sel_netnode_hash[idx].list.prev),
178 struct sel_netnode, list);
179 list_del_rcu(&tail->list);
Lai Jiangshan9801c602011-03-18 12:05:22 +0800180 kfree_rcu(tail, rcu);
Paul Moorea639e7ca2008-04-25 15:03:34 -0400181 } else
182 sel_netnode_hash[idx].size++;
Paul Moore224dfbd2008-01-29 08:38:13 -0500183}
184
185/**
186 * sel_netnode_sid_slow - Lookup the SID of a network address using the policy
187 * @addr: the IP address
188 * @family: the address family
189 * @sid: node SID
190 *
191 * Description:
192 * This function determines the SID of a network address by quering the
193 * security policy. The result is added to the network address table to
194 * speedup future queries. Returns zero on success, negative values on
195 * failure.
196 *
197 */
198static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid)
199{
Paul Moorea639e7ca2008-04-25 15:03:34 -0400200 int ret = -ENOMEM;
Paul Moore224dfbd2008-01-29 08:38:13 -0500201 struct sel_netnode *node;
202 struct sel_netnode *new = NULL;
203
204 spin_lock_bh(&sel_netnode_lock);
205 node = sel_netnode_find(addr, family);
206 if (node != NULL) {
207 *sid = node->nsec.sid;
Paul Moorea639e7ca2008-04-25 15:03:34 -0400208 spin_unlock_bh(&sel_netnode_lock);
209 return 0;
Paul Moore224dfbd2008-01-29 08:38:13 -0500210 }
211 new = kzalloc(sizeof(*new), GFP_ATOMIC);
Paul Moorea639e7ca2008-04-25 15:03:34 -0400212 if (new == NULL)
Paul Moore224dfbd2008-01-29 08:38:13 -0500213 goto out;
Paul Moore224dfbd2008-01-29 08:38:13 -0500214 switch (family) {
215 case PF_INET:
216 ret = security_node_sid(PF_INET,
Paul Moorea639e7ca2008-04-25 15:03:34 -0400217 addr, sizeof(struct in_addr), sid);
Paul Moore224dfbd2008-01-29 08:38:13 -0500218 new->nsec.addr.ipv4 = *(__be32 *)addr;
219 break;
220 case PF_INET6:
221 ret = security_node_sid(PF_INET6,
Paul Moorea639e7ca2008-04-25 15:03:34 -0400222 addr, sizeof(struct in6_addr), sid);
Paul Moore224dfbd2008-01-29 08:38:13 -0500223 ipv6_addr_copy(&new->nsec.addr.ipv6, addr);
224 break;
225 default:
226 BUG();
227 }
228 if (ret != 0)
229 goto out;
Paul Moorea639e7ca2008-04-25 15:03:34 -0400230
Paul Moore224dfbd2008-01-29 08:38:13 -0500231 new->nsec.family = family;
Paul Moorea639e7ca2008-04-25 15:03:34 -0400232 new->nsec.sid = *sid;
233 sel_netnode_insert(new);
Paul Moore224dfbd2008-01-29 08:38:13 -0500234
235out:
236 spin_unlock_bh(&sel_netnode_lock);
Paul Moore71f1cb02008-01-29 08:51:16 -0500237 if (unlikely(ret)) {
238 printk(KERN_WARNING
239 "SELinux: failure in sel_netnode_sid_slow(),"
240 " unable to determine network node label\n");
Paul Moore224dfbd2008-01-29 08:38:13 -0500241 kfree(new);
Paul Moore71f1cb02008-01-29 08:51:16 -0500242 }
Paul Moore224dfbd2008-01-29 08:38:13 -0500243 return ret;
244}
245
246/**
247 * sel_netnode_sid - Lookup the SID of a network address
248 * @addr: the IP address
249 * @family: the address family
250 * @sid: node SID
251 *
252 * Description:
253 * This function determines the SID of a network address using the fastest
254 * method possible. First the address table is queried, but if an entry
255 * can't be found then the policy is queried and the result is added to the
256 * table to speedup future queries. Returns zero on success, negative values
257 * on failure.
258 *
259 */
260int sel_netnode_sid(void *addr, u16 family, u32 *sid)
261{
262 struct sel_netnode *node;
263
264 rcu_read_lock();
265 node = sel_netnode_find(addr, family);
266 if (node != NULL) {
267 *sid = node->nsec.sid;
268 rcu_read_unlock();
269 return 0;
270 }
271 rcu_read_unlock();
272
273 return sel_netnode_sid_slow(addr, family, sid);
274}
275
276/**
277 * sel_netnode_flush - Flush the entire network address table
278 *
279 * Description:
280 * Remove all entries from the network address table.
281 *
282 */
283static void sel_netnode_flush(void)
284{
Paul Moorea639e7ca2008-04-25 15:03:34 -0400285 unsigned int idx;
286 struct sel_netnode *node, *node_tmp;
Paul Moore224dfbd2008-01-29 08:38:13 -0500287
288 spin_lock_bh(&sel_netnode_lock);
Paul Moorea639e7ca2008-04-25 15:03:34 -0400289 for (idx = 0; idx < SEL_NETNODE_HASH_SIZE; idx++) {
290 list_for_each_entry_safe(node, node_tmp,
291 &sel_netnode_hash[idx].list, list) {
292 list_del_rcu(&node->list);
Lai Jiangshan9801c602011-03-18 12:05:22 +0800293 kfree_rcu(node, rcu);
Paul Moorea639e7ca2008-04-25 15:03:34 -0400294 }
295 sel_netnode_hash[idx].size = 0;
296 }
Paul Moore224dfbd2008-01-29 08:38:13 -0500297 spin_unlock_bh(&sel_netnode_lock);
298}
299
300static int sel_netnode_avc_callback(u32 event, u32 ssid, u32 tsid,
301 u16 class, u32 perms, u32 *retained)
302{
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
323 ret = avc_add_callback(sel_netnode_avc_callback, AVC_CALLBACK_RESET,
Eric Paris7b6b2392008-04-18 17:38:25 -0400324 SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
Paul Moore224dfbd2008-01-29 08:38:13 -0500325 if (ret != 0)
326 panic("avc_add_callback() failed, error %d\n", ret);
327
328 return ret;
329}
330
331__initcall(sel_netnode_init);