1 /*
2 * NetLabel Network Address Lists
3 *
4 * This file contains network address list functions used to manage ordered
5 * lists of network addresses for use by the NetLabel subsystem. The NetLabel
6 * system manages static and dynamic label mappings for network protocols such
7 * as CIPSO and RIPSO.
8 *
9 * Author: Paul Moore <paul@paul-moore.com>
10 *
11 */
12
13 /*
14 * (c) Copyright Hewlett-Packard Development Company, L.P., 2008
15 *
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation; either version 2 of the License, or
19 * (at your option) any later version.
20 *
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
24 * the GNU General Public License for more details.
25 *
26 * You should have received a copy of the GNU General Public License
27 * along with this program; if not, see <http://www.gnu.org/licenses/>.
28 *
29 */
30
31 #include <linux/types.h>
32 #include <linux/rcupdate.h>
33 #include <linux/list.h>
34 #include <linux/spinlock.h>
35 #include <linux/in.h>
36 #include <linux/in6.h>
37 #include <linux/ip.h>
38 #include <linux/ipv6.h>
39 #include <net/ip.h>
40 #include <net/ipv6.h>
41 #include <linux/audit.h>
42
43 #include "netlabel_addrlist.h"
44
45 /*
46 * Address List Functions
47 */
48
49 /**
50 * netlbl_af4list_search - Search for a matching IPv4 address entry
51 * @addr: IPv4 address
52 * @head: the list head
53 *
54 * Description:
55 * Searches the IPv4 address list given by @head. If a matching address entry
56 * is found it is returned, otherwise NULL is returned. The caller is
57 * responsible for calling the rcu_read_[un]lock() functions.
58 *
59 */
netlbl_af4list_search(__be32 addr,struct list_head * head)60 struct netlbl_af4list *netlbl_af4list_search(__be32 addr,
61 struct list_head *head)
62 {
63 struct netlbl_af4list *iter;
64
65 list_for_each_entry_rcu(iter, head, list)
66 if (iter->valid && (addr & iter->mask) == iter->addr)
67 return iter;
68
69 return NULL;
70 }
71
72 /**
73 * netlbl_af4list_search_exact - Search for an exact IPv4 address entry
74 * @addr: IPv4 address
75 * @mask: IPv4 address mask
76 * @head: the list head
77 *
78 * Description:
79 * Searches the IPv4 address list given by @head. If an exact match if found
80 * it is returned, otherwise NULL is returned. The caller is responsible for
81 * calling the rcu_read_[un]lock() functions.
82 *
83 */
netlbl_af4list_search_exact(__be32 addr,__be32 mask,struct list_head * head)84 struct netlbl_af4list *netlbl_af4list_search_exact(__be32 addr,
85 __be32 mask,
86 struct list_head *head)
87 {
88 struct netlbl_af4list *iter;
89
90 list_for_each_entry_rcu(iter, head, list)
91 if (iter->valid && iter->addr == addr && iter->mask == mask)
92 return iter;
93
94 return NULL;
95 }
96
97
98 #if IS_ENABLED(CONFIG_IPV6)
99 /**
100 * netlbl_af6list_search - Search for a matching IPv6 address entry
101 * @addr: IPv6 address
102 * @head: the list head
103 *
104 * Description:
105 * Searches the IPv6 address list given by @head. If a matching address entry
106 * is found it is returned, otherwise NULL is returned. The caller is
107 * responsible for calling the rcu_read_[un]lock() functions.
108 *
109 */
netlbl_af6list_search(const struct in6_addr * addr,struct list_head * head)110 struct netlbl_af6list *netlbl_af6list_search(const struct in6_addr *addr,
111 struct list_head *head)
112 {
113 struct netlbl_af6list *iter;
114
115 list_for_each_entry_rcu(iter, head, list)
116 if (iter->valid &&
117 ipv6_masked_addr_cmp(&iter->addr, &iter->mask, addr) == 0)
118 return iter;
119
120 return NULL;
121 }
122
123 /**
124 * netlbl_af6list_search_exact - Search for an exact IPv6 address entry
125 * @addr: IPv6 address
126 * @mask: IPv6 address mask
127 * @head: the list head
128 *
129 * Description:
130 * Searches the IPv6 address list given by @head. If an exact match if found
131 * it is returned, otherwise NULL is returned. The caller is responsible for
132 * calling the rcu_read_[un]lock() functions.
133 *
134 */
netlbl_af6list_search_exact(const struct in6_addr * addr,const struct in6_addr * mask,struct list_head * head)135 struct netlbl_af6list *netlbl_af6list_search_exact(const struct in6_addr *addr,
136 const struct in6_addr *mask,
137 struct list_head *head)
138 {
139 struct netlbl_af6list *iter;
140
141 list_for_each_entry_rcu(iter, head, list)
142 if (iter->valid &&
143 ipv6_addr_equal(&iter->addr, addr) &&
144 ipv6_addr_equal(&iter->mask, mask))
145 return iter;
146
147 return NULL;
148 }
149 #endif /* IPv6 */
150
151 /**
152 * netlbl_af4list_add - Add a new IPv4 address entry to a list
153 * @entry: address entry
154 * @head: the list head
155 *
156 * Description:
157 * Add a new address entry to the list pointed to by @head. On success zero is
158 * returned, otherwise a negative value is returned. The caller is responsible
159 * for calling the necessary locking functions.
160 *
161 */
netlbl_af4list_add(struct netlbl_af4list * entry,struct list_head * head)162 int netlbl_af4list_add(struct netlbl_af4list *entry, struct list_head *head)
163 {
164 struct netlbl_af4list *iter;
165
166 iter = netlbl_af4list_search(entry->addr, head);
167 if (iter != NULL &&
168 iter->addr == entry->addr && iter->mask == entry->mask)
169 return -EEXIST;
170
171 /* in order to speed up address searches through the list (the common
172 * case) we need to keep the list in order based on the size of the
173 * address mask such that the entry with the widest mask (smallest
174 * numerical value) appears first in the list */
175 list_for_each_entry_rcu(iter, head, list)
176 if (iter->valid &&
177 ntohl(entry->mask) > ntohl(iter->mask)) {
178 __list_add_rcu(&entry->list,
179 iter->list.prev,
180 &iter->list);
181 return 0;
182 }
183 list_add_tail_rcu(&entry->list, head);
184 return 0;
185 }
186
187 #if IS_ENABLED(CONFIG_IPV6)
188 /**
189 * netlbl_af6list_add - Add a new IPv6 address entry to a list
190 * @entry: address entry
191 * @head: the list head
192 *
193 * Description:
194 * Add a new address entry to the list pointed to by @head. On success zero is
195 * returned, otherwise a negative value is returned. The caller is responsible
196 * for calling the necessary locking functions.
197 *
198 */
netlbl_af6list_add(struct netlbl_af6list * entry,struct list_head * head)199 int netlbl_af6list_add(struct netlbl_af6list *entry, struct list_head *head)
200 {
201 struct netlbl_af6list *iter;
202
203 iter = netlbl_af6list_search(&entry->addr, head);
204 if (iter != NULL &&
205 ipv6_addr_equal(&iter->addr, &entry->addr) &&
206 ipv6_addr_equal(&iter->mask, &entry->mask))
207 return -EEXIST;
208
209 /* in order to speed up address searches through the list (the common
210 * case) we need to keep the list in order based on the size of the
211 * address mask such that the entry with the widest mask (smallest
212 * numerical value) appears first in the list */
213 list_for_each_entry_rcu(iter, head, list)
214 if (iter->valid &&
215 ipv6_addr_cmp(&entry->mask, &iter->mask) > 0) {
216 __list_add_rcu(&entry->list,
217 iter->list.prev,
218 &iter->list);
219 return 0;
220 }
221 list_add_tail_rcu(&entry->list, head);
222 return 0;
223 }
224 #endif /* IPv6 */
225
226 /**
227 * netlbl_af4list_remove_entry - Remove an IPv4 address entry
228 * @entry: address entry
229 *
230 * Description:
231 * Remove the specified IP address entry. The caller is responsible for
232 * calling the necessary locking functions.
233 *
234 */
netlbl_af4list_remove_entry(struct netlbl_af4list * entry)235 void netlbl_af4list_remove_entry(struct netlbl_af4list *entry)
236 {
237 entry->valid = 0;
238 list_del_rcu(&entry->list);
239 }
240
241 /**
242 * netlbl_af4list_remove - Remove an IPv4 address entry
243 * @addr: IP address
244 * @mask: IP address mask
245 * @head: the list head
246 *
247 * Description:
248 * Remove an IP address entry from the list pointed to by @head. Returns the
249 * entry on success, NULL on failure. The caller is responsible for calling
250 * the necessary locking functions.
251 *
252 */
netlbl_af4list_remove(__be32 addr,__be32 mask,struct list_head * head)253 struct netlbl_af4list *netlbl_af4list_remove(__be32 addr, __be32 mask,
254 struct list_head *head)
255 {
256 struct netlbl_af4list *entry;
257
258 entry = netlbl_af4list_search_exact(addr, mask, head);
259 if (entry == NULL)
260 return NULL;
261 netlbl_af4list_remove_entry(entry);
262 return entry;
263 }
264
265 #if IS_ENABLED(CONFIG_IPV6)
266 /**
267 * netlbl_af6list_remove_entry - Remove an IPv6 address entry
268 * @entry: address entry
269 *
270 * Description:
271 * Remove the specified IP address entry. The caller is responsible for
272 * calling the necessary locking functions.
273 *
274 */
netlbl_af6list_remove_entry(struct netlbl_af6list * entry)275 void netlbl_af6list_remove_entry(struct netlbl_af6list *entry)
276 {
277 entry->valid = 0;
278 list_del_rcu(&entry->list);
279 }
280
281 /**
282 * netlbl_af6list_remove - Remove an IPv6 address entry
283 * @addr: IP address
284 * @mask: IP address mask
285 * @head: the list head
286 *
287 * Description:
288 * Remove an IP address entry from the list pointed to by @head. Returns the
289 * entry on success, NULL on failure. The caller is responsible for calling
290 * the necessary locking functions.
291 *
292 */
netlbl_af6list_remove(const struct in6_addr * addr,const struct in6_addr * mask,struct list_head * head)293 struct netlbl_af6list *netlbl_af6list_remove(const struct in6_addr *addr,
294 const struct in6_addr *mask,
295 struct list_head *head)
296 {
297 struct netlbl_af6list *entry;
298
299 entry = netlbl_af6list_search_exact(addr, mask, head);
300 if (entry == NULL)
301 return NULL;
302 netlbl_af6list_remove_entry(entry);
303 return entry;
304 }
305 #endif /* IPv6 */
306
307 /*
308 * Audit Helper Functions
309 */
310
311 #ifdef CONFIG_AUDIT
312 /**
313 * netlbl_af4list_audit_addr - Audit an IPv4 address
314 * @audit_buf: audit buffer
315 * @src: true if source address, false if destination
316 * @dev: network interface
317 * @addr: IP address
318 * @mask: IP address mask
319 *
320 * Description:
321 * Write the IPv4 address and address mask, if necessary, to @audit_buf.
322 *
323 */
netlbl_af4list_audit_addr(struct audit_buffer * audit_buf,int src,const char * dev,__be32 addr,__be32 mask)324 void netlbl_af4list_audit_addr(struct audit_buffer *audit_buf,
325 int src, const char *dev,
326 __be32 addr, __be32 mask)
327 {
328 u32 mask_val = ntohl(mask);
329 char *dir = (src ? "src" : "dst");
330
331 if (dev != NULL)
332 audit_log_format(audit_buf, " netif=%s", dev);
333 audit_log_format(audit_buf, " %s=%pI4", dir, &addr);
334 if (mask_val != 0xffffffff) {
335 u32 mask_len = 0;
336 while (mask_val > 0) {
337 mask_val <<= 1;
338 mask_len++;
339 }
340 audit_log_format(audit_buf, " %s_prefixlen=%d", dir, mask_len);
341 }
342 }
343
344 #if IS_ENABLED(CONFIG_IPV6)
345 /**
346 * netlbl_af6list_audit_addr - Audit an IPv6 address
347 * @audit_buf: audit buffer
348 * @src: true if source address, false if destination
349 * @dev: network interface
350 * @addr: IP address
351 * @mask: IP address mask
352 *
353 * Description:
354 * Write the IPv6 address and address mask, if necessary, to @audit_buf.
355 *
356 */
netlbl_af6list_audit_addr(struct audit_buffer * audit_buf,int src,const char * dev,const struct in6_addr * addr,const struct in6_addr * mask)357 void netlbl_af6list_audit_addr(struct audit_buffer *audit_buf,
358 int src,
359 const char *dev,
360 const struct in6_addr *addr,
361 const struct in6_addr *mask)
362 {
363 char *dir = (src ? "src" : "dst");
364
365 if (dev != NULL)
366 audit_log_format(audit_buf, " netif=%s", dev);
367 audit_log_format(audit_buf, " %s=%pI6", dir, addr);
368 if (ntohl(mask->s6_addr32[3]) != 0xffffffff) {
369 u32 mask_len = 0;
370 u32 mask_val;
371 int iter = -1;
372 while (ntohl(mask->s6_addr32[++iter]) == 0xffffffff)
373 mask_len += 32;
374 mask_val = ntohl(mask->s6_addr32[iter]);
375 while (mask_val > 0) {
376 mask_val <<= 1;
377 mask_len++;
378 }
379 audit_log_format(audit_buf, " %s_prefixlen=%d", dir, mask_len);
380 }
381 }
382 #endif /* IPv6 */
383 #endif /* CONFIG_AUDIT */
384