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, write to the Free Software
28  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
29  *
30  */
31 
32 #include <linux/types.h>
33 #include <linux/rcupdate.h>
34 #include <linux/list.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 #include <linux/audit.h>
43 
44 #include "netlabel_addrlist.h"
45 
46 /*
47  * Address List Functions
48  */
49 
50 /**
51  * netlbl_af4list_search - Search for a matching IPv4 address entry
52  * @addr: IPv4 address
53  * @head: the list head
54  *
55  * Description:
56  * Searches the IPv4 address list given by @head.  If a matching address entry
57  * is found it is returned, otherwise NULL is returned.  The caller is
58  * responsible for calling the rcu_read_[un]lock() functions.
59  *
60  */
61 struct netlbl_af4list *netlbl_af4list_search(__be32 addr,
62 					     struct list_head *head)
63 {
64 	struct netlbl_af4list *iter;
65 
66 	list_for_each_entry_rcu(iter, head, list)
67 		if (iter->valid && (addr & iter->mask) == iter->addr)
68 			return iter;
69 
70 	return NULL;
71 }
72 
73 /**
74  * netlbl_af4list_search_exact - Search for an exact IPv4 address entry
75  * @addr: IPv4 address
76  * @mask: IPv4 address mask
77  * @head: the list head
78  *
79  * Description:
80  * Searches the IPv4 address list given by @head.  If an exact match if found
81  * it is returned, otherwise NULL is returned.  The caller is responsible for
82  * calling the rcu_read_[un]lock() functions.
83  *
84  */
85 struct netlbl_af4list *netlbl_af4list_search_exact(__be32 addr,
86 						   __be32 mask,
87 						   struct list_head *head)
88 {
89 	struct netlbl_af4list *iter;
90 
91 	list_for_each_entry_rcu(iter, head, list)
92 		if (iter->valid && iter->addr == addr && iter->mask == mask)
93 			return iter;
94 
95 	return NULL;
96 }
97 
98 
99 #if IS_ENABLED(CONFIG_IPV6)
100 /**
101  * netlbl_af6list_search - Search for a matching IPv6 address entry
102  * @addr: IPv6 address
103  * @head: the list head
104  *
105  * Description:
106  * Searches the IPv6 address list given by @head.  If a matching address entry
107  * is found it is returned, otherwise NULL is returned.  The caller is
108  * responsible for calling the rcu_read_[un]lock() functions.
109  *
110  */
111 struct netlbl_af6list *netlbl_af6list_search(const struct in6_addr *addr,
112 					     struct list_head *head)
113 {
114 	struct netlbl_af6list *iter;
115 
116 	list_for_each_entry_rcu(iter, head, list)
117 		if (iter->valid &&
118 		    ipv6_masked_addr_cmp(&iter->addr, &iter->mask, addr) == 0)
119 			return iter;
120 
121 	return NULL;
122 }
123 
124 /**
125  * netlbl_af6list_search_exact - Search for an exact IPv6 address entry
126  * @addr: IPv6 address
127  * @mask: IPv6 address mask
128  * @head: the list head
129  *
130  * Description:
131  * Searches the IPv6 address list given by @head.  If an exact match if found
132  * it is returned, otherwise NULL is returned.  The caller is responsible for
133  * calling the rcu_read_[un]lock() functions.
134  *
135  */
136 struct netlbl_af6list *netlbl_af6list_search_exact(const struct in6_addr *addr,
137 						   const struct in6_addr *mask,
138 						   struct list_head *head)
139 {
140 	struct netlbl_af6list *iter;
141 
142 	list_for_each_entry_rcu(iter, head, list)
143 		if (iter->valid &&
144 		    ipv6_addr_equal(&iter->addr, addr) &&
145 		    ipv6_addr_equal(&iter->mask, mask))
146 			return iter;
147 
148 	return NULL;
149 }
150 #endif /* IPv6 */
151 
152 /**
153  * netlbl_af4list_add - Add a new IPv4 address entry to a list
154  * @entry: address entry
155  * @head: the list head
156  *
157  * Description:
158  * Add a new address entry to the list pointed to by @head.  On success zero is
159  * returned, otherwise a negative value is returned.  The caller is responsible
160  * for calling the necessary locking functions.
161  *
162  */
163 int netlbl_af4list_add(struct netlbl_af4list *entry, struct list_head *head)
164 {
165 	struct netlbl_af4list *iter;
166 
167 	iter = netlbl_af4list_search(entry->addr, head);
168 	if (iter != NULL &&
169 	    iter->addr == entry->addr && iter->mask == entry->mask)
170 		return -EEXIST;
171 
172 	/* in order to speed up address searches through the list (the common
173 	 * case) we need to keep the list in order based on the size of the
174 	 * address mask such that the entry with the widest mask (smallest
175 	 * numerical value) appears first in the list */
176 	list_for_each_entry_rcu(iter, head, list)
177 		if (iter->valid &&
178 		    ntohl(entry->mask) > ntohl(iter->mask)) {
179 			__list_add_rcu(&entry->list,
180 				       iter->list.prev,
181 				       &iter->list);
182 			return 0;
183 		}
184 	list_add_tail_rcu(&entry->list, head);
185 	return 0;
186 }
187 
188 #if IS_ENABLED(CONFIG_IPV6)
189 /**
190  * netlbl_af6list_add - Add a new IPv6 address entry to a list
191  * @entry: address entry
192  * @head: the list head
193  *
194  * Description:
195  * Add a new address entry to the list pointed to by @head.  On success zero is
196  * returned, otherwise a negative value is returned.  The caller is responsible
197  * for calling the necessary locking functions.
198  *
199  */
200 int netlbl_af6list_add(struct netlbl_af6list *entry, struct list_head *head)
201 {
202 	struct netlbl_af6list *iter;
203 
204 	iter = netlbl_af6list_search(&entry->addr, head);
205 	if (iter != NULL &&
206 	    ipv6_addr_equal(&iter->addr, &entry->addr) &&
207 	    ipv6_addr_equal(&iter->mask, &entry->mask))
208 		return -EEXIST;
209 
210 	/* in order to speed up address searches through the list (the common
211 	 * case) we need to keep the list in order based on the size of the
212 	 * address mask such that the entry with the widest mask (smallest
213 	 * numerical value) appears first in the list */
214 	list_for_each_entry_rcu(iter, head, list)
215 		if (iter->valid &&
216 		    ipv6_addr_cmp(&entry->mask, &iter->mask) > 0) {
217 			__list_add_rcu(&entry->list,
218 				       iter->list.prev,
219 				       &iter->list);
220 			return 0;
221 		}
222 	list_add_tail_rcu(&entry->list, head);
223 	return 0;
224 }
225 #endif /* IPv6 */
226 
227 /**
228  * netlbl_af4list_remove_entry - Remove an IPv4 address entry
229  * @entry: address entry
230  *
231  * Description:
232  * Remove the specified IP address entry.  The caller is responsible for
233  * calling the necessary locking functions.
234  *
235  */
236 void netlbl_af4list_remove_entry(struct netlbl_af4list *entry)
237 {
238 	entry->valid = 0;
239 	list_del_rcu(&entry->list);
240 }
241 
242 /**
243  * netlbl_af4list_remove - Remove an IPv4 address entry
244  * @addr: IP address
245  * @mask: IP address mask
246  * @head: the list head
247  *
248  * Description:
249  * Remove an IP address entry from the list pointed to by @head.  Returns the
250  * entry on success, NULL on failure.  The caller is responsible for calling
251  * the necessary locking functions.
252  *
253  */
254 struct netlbl_af4list *netlbl_af4list_remove(__be32 addr, __be32 mask,
255 					     struct list_head *head)
256 {
257 	struct netlbl_af4list *entry;
258 
259 	entry = netlbl_af4list_search_exact(addr, mask, head);
260 	if (entry == NULL)
261 		return NULL;
262 	netlbl_af4list_remove_entry(entry);
263 	return entry;
264 }
265 
266 #if IS_ENABLED(CONFIG_IPV6)
267 /**
268  * netlbl_af6list_remove_entry - Remove an IPv6 address entry
269  * @entry: address entry
270  *
271  * Description:
272  * Remove the specified IP address entry.  The caller is responsible for
273  * calling the necessary locking functions.
274  *
275  */
276 void netlbl_af6list_remove_entry(struct netlbl_af6list *entry)
277 {
278 	entry->valid = 0;
279 	list_del_rcu(&entry->list);
280 }
281 
282 /**
283  * netlbl_af6list_remove - Remove an IPv6 address entry
284  * @addr: IP address
285  * @mask: IP address mask
286  * @head: the list head
287  *
288  * Description:
289  * Remove an IP address entry from the list pointed to by @head.  Returns the
290  * entry on success, NULL on failure.  The caller is responsible for calling
291  * the necessary locking functions.
292  *
293  */
294 struct netlbl_af6list *netlbl_af6list_remove(const struct in6_addr *addr,
295 					     const struct in6_addr *mask,
296 					     struct list_head *head)
297 {
298 	struct netlbl_af6list *entry;
299 
300 	entry = netlbl_af6list_search_exact(addr, mask, head);
301 	if (entry == NULL)
302 		return NULL;
303 	netlbl_af6list_remove_entry(entry);
304 	return entry;
305 }
306 #endif /* IPv6 */
307 
308 /*
309  * Audit Helper Functions
310  */
311 
312 #ifdef CONFIG_AUDIT
313 /**
314  * netlbl_af4list_audit_addr - Audit an IPv4 address
315  * @audit_buf: audit buffer
316  * @src: true if source address, false if destination
317  * @dev: network interface
318  * @addr: IP address
319  * @mask: IP address mask
320  *
321  * Description:
322  * Write the IPv4 address and address mask, if necessary, to @audit_buf.
323  *
324  */
325 void netlbl_af4list_audit_addr(struct audit_buffer *audit_buf,
326 					int src, const char *dev,
327 					__be32 addr, __be32 mask)
328 {
329 	u32 mask_val = ntohl(mask);
330 	char *dir = (src ? "src" : "dst");
331 
332 	if (dev != NULL)
333 		audit_log_format(audit_buf, " netif=%s", dev);
334 	audit_log_format(audit_buf, " %s=%pI4", dir, &addr);
335 	if (mask_val != 0xffffffff) {
336 		u32 mask_len = 0;
337 		while (mask_val > 0) {
338 			mask_val <<= 1;
339 			mask_len++;
340 		}
341 		audit_log_format(audit_buf, " %s_prefixlen=%d", dir, mask_len);
342 	}
343 }
344 
345 #if IS_ENABLED(CONFIG_IPV6)
346 /**
347  * netlbl_af6list_audit_addr - Audit an IPv6 address
348  * @audit_buf: audit buffer
349  * @src: true if source address, false if destination
350  * @dev: network interface
351  * @addr: IP address
352  * @mask: IP address mask
353  *
354  * Description:
355  * Write the IPv6 address and address mask, if necessary, to @audit_buf.
356  *
357  */
358 void netlbl_af6list_audit_addr(struct audit_buffer *audit_buf,
359 				 int src,
360 				 const char *dev,
361 				 const struct in6_addr *addr,
362 				 const struct in6_addr *mask)
363 {
364 	char *dir = (src ? "src" : "dst");
365 
366 	if (dev != NULL)
367 		audit_log_format(audit_buf, " netif=%s", dev);
368 	audit_log_format(audit_buf, " %s=%pI6", dir, addr);
369 	if (ntohl(mask->s6_addr32[3]) != 0xffffffff) {
370 		u32 mask_len = 0;
371 		u32 mask_val;
372 		int iter = -1;
373 		while (ntohl(mask->s6_addr32[++iter]) == 0xffffffff)
374 			mask_len += 32;
375 		mask_val = ntohl(mask->s6_addr32[iter]);
376 		while (mask_val > 0) {
377 			mask_val <<= 1;
378 			mask_len++;
379 		}
380 		audit_log_format(audit_buf, " %s_prefixlen=%d", dir, mask_len);
381 	}
382 }
383 #endif /* IPv6 */
384 #endif /* CONFIG_AUDIT */
385