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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Network node table
4 *
5 * SELinux must keep a mapping of network nodes to labels/SIDs. This
6 * mapping is maintained as part of the normal policy but a fast cache is
7 * needed to reduce the lookup overhead since most of these queries happen on
8 * a per-packet basis.
9 *
10 * Author: Paul Moore <paul@paul-moore.com>
11 *
12 * This code is heavily based on the "netif" concept originally developed by
13 * James Morris <jmorris@redhat.com>
14 * (see security/selinux/netif.c for more information)
15 */
16
17/*
18 * (c) Copyright Hewlett-Packard Development Company, L.P., 2007
19 */
20
21#include <linux/types.h>
22#include <linux/rcupdate.h>
23#include <linux/list.h>
24#include <linux/slab.h>
25#include <linux/spinlock.h>
26#include <linux/in.h>
27#include <linux/in6.h>
28#include <linux/ip.h>
29#include <linux/ipv6.h>
30#include <net/ip.h>
31#include <net/ipv6.h>
32
33#include "netnode.h"
34#include "objsec.h"
35
36#define SEL_NETNODE_HASH_SIZE 256
37#define SEL_NETNODE_HASH_BKT_LIMIT 16
38
39struct sel_netnode_bkt {
40 unsigned int size;
41 struct list_head list;
42};
43
44struct sel_netnode {
45 struct netnode_security_struct nsec;
46
47 struct list_head list;
48 struct rcu_head rcu;
49};
50
51/* NOTE: we are using a combined hash table for both IPv4 and IPv6, the reason
52 * for this is that I suspect most users will not make heavy use of both
53 * address families at the same time so one table will usually end up wasted,
54 * if this becomes a problem we can always add a hash table for each address
55 * family later */
56
57static DEFINE_SPINLOCK(sel_netnode_lock);
58static struct sel_netnode_bkt sel_netnode_hash[SEL_NETNODE_HASH_SIZE];
59
60/**
61 * sel_netnode_hashfn_ipv4 - IPv4 hashing function for the node table
62 * @addr: IPv4 address
63 *
64 * Description:
65 * This is the IPv4 hashing function for the node interface table, it returns
66 * the bucket number for the given IP address.
67 *
68 */
69static unsigned int sel_netnode_hashfn_ipv4(__be32 addr)
70{
71 /* at some point we should determine if the mismatch in byte order
72 * affects the hash function dramatically */
73 return (addr & (SEL_NETNODE_HASH_SIZE - 1));
74}
75
76/**
77 * sel_netnode_hashfn_ipv6 - IPv6 hashing function for the node table
78 * @addr: IPv6 address
79 *
80 * Description:
81 * This is the IPv6 hashing function for the node interface table, it returns
82 * the bucket number for the given IP address.
83 *
84 */
85static unsigned int sel_netnode_hashfn_ipv6(const struct in6_addr *addr)
86{
87 /* just hash the least significant 32 bits to keep things fast (they
88 * are the most likely to be different anyway), we can revisit this
89 * later if needed */
90 return (addr->s6_addr32[3] & (SEL_NETNODE_HASH_SIZE - 1));
91}
92
93/**
94 * sel_netnode_find - Search for a node record
95 * @addr: IP address
96 * @family: address family
97 *
98 * Description:
99 * Search the network node table and return the record matching @addr. If an
100 * entry can not be found in the table return NULL.
101 *
102 */
103static struct sel_netnode *sel_netnode_find(const void *addr, u16 family)
104{
105 unsigned int idx;
106 struct sel_netnode *node;
107
108 switch (family) {
109 case PF_INET:
110 idx = sel_netnode_hashfn_ipv4(*(const __be32 *)addr);
111 break;
112 case PF_INET6:
113 idx = sel_netnode_hashfn_ipv6(addr);
114 break;
115 default:
116 BUG();
117 return NULL;
118 }
119
120 list_for_each_entry_rcu(node, &sel_netnode_hash[idx].list, list)
121 if (node->nsec.family == family)
122 switch (family) {
123 case PF_INET:
124 if (node->nsec.addr.ipv4 == *(const __be32 *)addr)
125 return node;
126 break;
127 case PF_INET6:
128 if (ipv6_addr_equal(&node->nsec.addr.ipv6,
129 addr))
130 return node;
131 break;
132 }
133
134 return NULL;
135}
136
137/**
138 * sel_netnode_insert - Insert a new node into the table
139 * @node: the new node record
140 *
141 * Description:
142 * Add a new node record to the network address hash table.
143 *
144 */
145static void sel_netnode_insert(struct sel_netnode *node)
146{
147 unsigned int idx;
148
149 switch (node->nsec.family) {
150 case PF_INET:
151 idx = sel_netnode_hashfn_ipv4(node->nsec.addr.ipv4);
152 break;
153 case PF_INET6:
154 idx = sel_netnode_hashfn_ipv6(&node->nsec.addr.ipv6);
155 break;
156 default:
157 BUG();
158 return;
159 }
160
161 /* we need to impose a limit on the growth of the hash table so check
162 * this bucket to make sure it is within the specified bounds */
163 list_add_rcu(&node->list, &sel_netnode_hash[idx].list);
164 if (sel_netnode_hash[idx].size == SEL_NETNODE_HASH_BKT_LIMIT) {
165 struct sel_netnode *tail;
166 tail = list_entry(
167 rcu_dereference_protected(
168 list_tail_rcu(&sel_netnode_hash[idx].list),
169 lockdep_is_held(&sel_netnode_lock)),
170 struct sel_netnode, list);
171 list_del_rcu(&tail->list);
172 kfree_rcu(tail, rcu);
173 } else
174 sel_netnode_hash[idx].size++;
175}
176
177/**
178 * sel_netnode_sid_slow - Lookup the SID of a network address using the policy
179 * @addr: the IP address
180 * @family: the address family
181 * @sid: node SID
182 *
183 * Description:
184 * This function determines the SID of a network address by querying the
185 * security policy. The result is added to the network address table to
186 * speedup future queries. Returns zero on success, negative values on
187 * failure.
188 *
189 */
190static int sel_netnode_sid_slow(void *addr, u16 family, u32 *sid)
191{
192 int ret;
193 struct sel_netnode *node;
194 struct sel_netnode *new;
195
196 spin_lock_bh(&sel_netnode_lock);
197 node = sel_netnode_find(addr, family);
198 if (node != NULL) {
199 *sid = node->nsec.sid;
200 spin_unlock_bh(&sel_netnode_lock);
201 return 0;
202 }
203
204 new = kzalloc(sizeof(*new), GFP_ATOMIC);
205 switch (family) {
206 case PF_INET:
207 ret = security_node_sid(&selinux_state, PF_INET,
208 addr, sizeof(struct in_addr), sid);
209 if (new)
210 new->nsec.addr.ipv4 = *(__be32 *)addr;
211 break;
212 case PF_INET6:
213 ret = security_node_sid(&selinux_state, PF_INET6,
214 addr, sizeof(struct in6_addr), sid);
215 if (new)
216 new->nsec.addr.ipv6 = *(struct in6_addr *)addr;
217 break;
218 default:
219 BUG();
220 ret = -EINVAL;
221 }
222 if (ret == 0 && new) {
223 new->nsec.family = family;
224 new->nsec.sid = *sid;
225 sel_netnode_insert(new);
226 } else
227 kfree(new);
228
229 spin_unlock_bh(&sel_netnode_lock);
230 if (unlikely(ret))
231 pr_warn("SELinux: failure in %s(), unable to determine network node label\n",
232 __func__);
233 return ret;
234}
235
236/**
237 * sel_netnode_sid - Lookup the SID of a network address
238 * @addr: the IP address
239 * @family: the address family
240 * @sid: node SID
241 *
242 * Description:
243 * This function determines the SID of a network address using the fastest
244 * method possible. First the address table is queried, but if an entry
245 * can't be found then the policy is queried and the result is added to the
246 * table to speedup future queries. Returns zero on success, negative values
247 * on failure.
248 *
249 */
250int sel_netnode_sid(void *addr, u16 family, u32 *sid)
251{
252 struct sel_netnode *node;
253
254 rcu_read_lock();
255 node = sel_netnode_find(addr, family);
256 if (node != NULL) {
257 *sid = node->nsec.sid;
258 rcu_read_unlock();
259 return 0;
260 }
261 rcu_read_unlock();
262
263 return sel_netnode_sid_slow(addr, family, sid);
264}
265
266/**
267 * sel_netnode_flush - Flush the entire network address table
268 *
269 * Description:
270 * Remove all entries from the network address table.
271 *
272 */
273void sel_netnode_flush(void)
274{
275 unsigned int idx;
276 struct sel_netnode *node, *node_tmp;
277
278 spin_lock_bh(&sel_netnode_lock);
279 for (idx = 0; idx < SEL_NETNODE_HASH_SIZE; idx++) {
280 list_for_each_entry_safe(node, node_tmp,
281 &sel_netnode_hash[idx].list, list) {
282 list_del_rcu(&node->list);
283 kfree_rcu(node, rcu);
284 }
285 sel_netnode_hash[idx].size = 0;
286 }
287 spin_unlock_bh(&sel_netnode_lock);
288}
289
290static __init int sel_netnode_init(void)
291{
292 int iter;
293
294 if (!selinux_enabled_boot)
295 return 0;
296
297 for (iter = 0; iter < SEL_NETNODE_HASH_SIZE; iter++) {
298 INIT_LIST_HEAD(&sel_netnode_hash[iter].list);
299 sel_netnode_hash[iter].size = 0;
300 }
301
302 return 0;
303}
304
305__initcall(sel_netnode_init);
1/*
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 *
9 * Author: Paul Moore <paul@paul-moore.com>
10 *
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>
34#include <linux/slab.h>
35#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>
42
43#include "netnode.h"
44#include "objsec.h"
45
46#define SEL_NETNODE_HASH_SIZE 256
47#define SEL_NETNODE_HASH_BKT_LIMIT 16
48
49struct sel_netnode_bkt {
50 unsigned int size;
51 struct list_head list;
52};
53
54struct 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);
69static struct sel_netnode_bkt sel_netnode_hash[SEL_NETNODE_HASH_SIZE];
70
71/**
72 * 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 */
80static unsigned int sel_netnode_hashfn_ipv4(__be32 addr)
81{
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 */
96static unsigned int sel_netnode_hashfn_ipv6(const struct in6_addr *addr)
97{
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{
116 unsigned int idx;
117 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();
128 return NULL;
129 }
130
131 list_for_each_entry_rcu(node, &sel_netnode_hash[idx].list, list)
132 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:
153 * Add a new node record to the network address hash table.
154 *
155 */
156static void sel_netnode_insert(struct sel_netnode *node)
157{
158 unsigned int idx;
159
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 }
170
171 /* 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 */
173 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);
180 kfree_rcu(tail, rcu);
181 } else
182 sel_netnode_hash[idx].size++;
183}
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{
200 int ret = -ENOMEM;
201 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;
208 spin_unlock_bh(&sel_netnode_lock);
209 return 0;
210 }
211 new = kzalloc(sizeof(*new), GFP_ATOMIC);
212 if (new == NULL)
213 goto out;
214 switch (family) {
215 case PF_INET:
216 ret = security_node_sid(PF_INET,
217 addr, sizeof(struct in_addr), sid);
218 new->nsec.addr.ipv4 = *(__be32 *)addr;
219 break;
220 case PF_INET6:
221 ret = security_node_sid(PF_INET6,
222 addr, sizeof(struct in6_addr), sid);
223 ipv6_addr_copy(&new->nsec.addr.ipv6, addr);
224 break;
225 default:
226 BUG();
227 }
228 if (ret != 0)
229 goto out;
230
231 new->nsec.family = family;
232 new->nsec.sid = *sid;
233 sel_netnode_insert(new);
234
235out:
236 spin_unlock_bh(&sel_netnode_lock);
237 if (unlikely(ret)) {
238 printk(KERN_WARNING
239 "SELinux: failure in sel_netnode_sid_slow(),"
240 " unable to determine network node label\n");
241 kfree(new);
242 }
243 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{
285 unsigned int idx;
286 struct sel_netnode *node, *node_tmp;
287
288 spin_lock_bh(&sel_netnode_lock);
289 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);
293 kfree_rcu(node, rcu);
294 }
295 sel_netnode_hash[idx].size = 0;
296 }
297 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
318 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 }
322
323 ret = avc_add_callback(sel_netnode_avc_callback, AVC_CALLBACK_RESET,
324 SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
325 if (ret != 0)
326 panic("avc_add_callback() failed, error %d\n", ret);
327
328 return ret;
329}
330
331__initcall(sel_netnode_init);