1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * NetLabel Network Address Lists
4 *
5 * This file contains network address list functions used to manage ordered
6 * lists of network addresses for use by the NetLabel subsystem. The NetLabel
7 * system manages static and dynamic label mappings for network protocols such
8 * as CIPSO and RIPSO.
9 *
10 * Author: Paul Moore <paul@paul-moore.com>
11 */
12
13 /*
14 * (c) Copyright Hewlett-Packard Development Company, L.P., 2008
15 */
16
17 #include <linux/types.h>
18 #include <linux/rcupdate.h>
19 #include <linux/list.h>
20 #include <linux/spinlock.h>
21 #include <linux/in.h>
22 #include <linux/in6.h>
23 #include <linux/ip.h>
24 #include <linux/ipv6.h>
25 #include <net/ip.h>
26 #include <net/ipv6.h>
27 #include <linux/audit.h>
28
29 #include "netlabel_addrlist.h"
30
31 /*
32 * Address List Functions
33 */
34
35 /**
36 * netlbl_af4list_search - Search for a matching IPv4 address entry
37 * @addr: IPv4 address
38 * @head: the list head
39 *
40 * Description:
41 * Searches the IPv4 address list given by @head. If a matching address entry
42 * is found it is returned, otherwise NULL is returned. The caller is
43 * responsible for calling the rcu_read_[un]lock() functions.
44 *
45 */
46 struct netlbl_af4list *netlbl_af4list_search(__be32 addr,
47 struct list_head *head)
48 {
49 struct netlbl_af4list *iter;
50
51 list_for_each_entry_rcu(iter, head, list)
52 if (iter->valid && (addr & iter->mask) == iter->addr)
53 return iter;
54
55 return NULL;
56 }
57
58 /**
59 * netlbl_af4list_search_exact - Search for an exact IPv4 address entry
60 * @addr: IPv4 address
61 * @mask: IPv4 address mask
62 * @head: the list head
63 *
64 * Description:
65 * Searches the IPv4 address list given by @head. If an exact match if found
66 * it is returned, otherwise NULL is returned. The caller is responsible for
67 * calling the rcu_read_[un]lock() functions.
68 *
69 */
70 struct netlbl_af4list *netlbl_af4list_search_exact(__be32 addr,
71 __be32 mask,
72 struct list_head *head)
73 {
74 struct netlbl_af4list *iter;
75
76 list_for_each_entry_rcu(iter, head, list)
77 if (iter->valid && iter->addr == addr && iter->mask == mask)
78 return iter;
79
80 return NULL;
81 }
82
83
84 #if IS_ENABLED(CONFIG_IPV6)
85 /**
86 * netlbl_af6list_search - Search for a matching IPv6 address entry
87 * @addr: IPv6 address
88 * @head: the list head
89 *
90 * Description:
91 * Searches the IPv6 address list given by @head. If a matching address entry
92 * is found it is returned, otherwise NULL is returned. The caller is
93 * responsible for calling the rcu_read_[un]lock() functions.
94 *
95 */
96 struct netlbl_af6list *netlbl_af6list_search(const struct in6_addr *addr,
97 struct list_head *head)
98 {
99 struct netlbl_af6list *iter;
100
101 list_for_each_entry_rcu(iter, head, list)
102 if (iter->valid &&
103 ipv6_masked_addr_cmp(&iter->addr, &iter->mask, addr) == 0)
104 return iter;
105
106 return NULL;
107 }
108
109 /**
110 * netlbl_af6list_search_exact - Search for an exact IPv6 address entry
111 * @addr: IPv6 address
112 * @mask: IPv6 address mask
113 * @head: the list head
114 *
115 * Description:
116 * Searches the IPv6 address list given by @head. If an exact match if found
117 * it is returned, otherwise NULL is returned. The caller is responsible for
118 * calling the rcu_read_[un]lock() functions.
119 *
120 */
121 struct netlbl_af6list *netlbl_af6list_search_exact(const struct in6_addr *addr,
122 const struct in6_addr *mask,
123 struct list_head *head)
124 {
125 struct netlbl_af6list *iter;
126
127 list_for_each_entry_rcu(iter, head, list)
128 if (iter->valid &&
129 ipv6_addr_equal(&iter->addr, addr) &&
130 ipv6_addr_equal(&iter->mask, mask))
131 return iter;
132
133 return NULL;
134 }
135 #endif /* IPv6 */
136
137 /**
138 * netlbl_af4list_add - Add a new IPv4 address entry to a list
139 * @entry: address entry
140 * @head: the list head
141 *
142 * Description:
143 * Add a new address entry to the list pointed to by @head. On success zero is
144 * returned, otherwise a negative value is returned. The caller is responsible
145 * for calling the necessary locking functions.
146 *
147 */
148 int netlbl_af4list_add(struct netlbl_af4list *entry, struct list_head *head)
149 {
150 struct netlbl_af4list *iter;
151
152 iter = netlbl_af4list_search(entry->addr, head);
153 if (iter != NULL &&
154 iter->addr == entry->addr && iter->mask == entry->mask)
155 return -EEXIST;
156
157 /* in order to speed up address searches through the list (the common
158 * case) we need to keep the list in order based on the size of the
159 * address mask such that the entry with the widest mask (smallest
160 * numerical value) appears first in the list */
161 list_for_each_entry_rcu(iter, head, list)
162 if (iter->valid &&
163 ntohl(entry->mask) > ntohl(iter->mask)) {
164 __list_add_rcu(&entry->list,
165 iter->list.prev,
166 &iter->list);
167 return 0;
168 }
169 list_add_tail_rcu(&entry->list, head);
170 return 0;
171 }
172
173 #if IS_ENABLED(CONFIG_IPV6)
174 /**
175 * netlbl_af6list_add - Add a new IPv6 address entry to a list
176 * @entry: address entry
177 * @head: the list head
178 *
179 * Description:
180 * Add a new address entry to the list pointed to by @head. On success zero is
181 * returned, otherwise a negative value is returned. The caller is responsible
182 * for calling the necessary locking functions.
183 *
184 */
185 int netlbl_af6list_add(struct netlbl_af6list *entry, struct list_head *head)
186 {
187 struct netlbl_af6list *iter;
188
189 iter = netlbl_af6list_search(&entry->addr, head);
190 if (iter != NULL &&
191 ipv6_addr_equal(&iter->addr, &entry->addr) &&
192 ipv6_addr_equal(&iter->mask, &entry->mask))
193 return -EEXIST;
194
195 /* in order to speed up address searches through the list (the common
196 * case) we need to keep the list in order based on the size of the
197 * address mask such that the entry with the widest mask (smallest
198 * numerical value) appears first in the list */
199 list_for_each_entry_rcu(iter, head, list)
200 if (iter->valid &&
201 ipv6_addr_cmp(&entry->mask, &iter->mask) > 0) {
202 __list_add_rcu(&entry->list,
203 iter->list.prev,
204 &iter->list);
205 return 0;
206 }
207 list_add_tail_rcu(&entry->list, head);
208 return 0;
209 }
210 #endif /* IPv6 */
211
212 /**
213 * netlbl_af4list_remove_entry - Remove an IPv4 address entry
214 * @entry: address entry
215 *
216 * Description:
217 * Remove the specified IP address entry. The caller is responsible for
218 * calling the necessary locking functions.
219 *
220 */
221 void netlbl_af4list_remove_entry(struct netlbl_af4list *entry)
222 {
223 entry->valid = 0;
224 list_del_rcu(&entry->list);
225 }
226
227 /**
228 * netlbl_af4list_remove - Remove an IPv4 address entry
229 * @addr: IP address
230 * @mask: IP address mask
231 * @head: the list head
232 *
233 * Description:
234 * Remove an IP address entry from the list pointed to by @head. Returns the
235 * entry on success, NULL on failure. The caller is responsible for calling
236 * the necessary locking functions.
237 *
238 */
239 struct netlbl_af4list *netlbl_af4list_remove(__be32 addr, __be32 mask,
240 struct list_head *head)
241 {
242 struct netlbl_af4list *entry;
243
244 entry = netlbl_af4list_search_exact(addr, mask, head);
245 if (entry == NULL)
246 return NULL;
247 netlbl_af4list_remove_entry(entry);
248 return entry;
249 }
250
251 #if IS_ENABLED(CONFIG_IPV6)
252 /**
253 * netlbl_af6list_remove_entry - Remove an IPv6 address entry
254 * @entry: address entry
255 *
256 * Description:
257 * Remove the specified IP address entry. The caller is responsible for
258 * calling the necessary locking functions.
259 *
260 */
261 void netlbl_af6list_remove_entry(struct netlbl_af6list *entry)
262 {
263 entry->valid = 0;
264 list_del_rcu(&entry->list);
265 }
266
267 /**
268 * netlbl_af6list_remove - Remove an IPv6 address entry
269 * @addr: IP address
270 * @mask: IP address mask
271 * @head: the list head
272 *
273 * Description:
274 * Remove an IP address entry from the list pointed to by @head. Returns the
275 * entry on success, NULL on failure. The caller is responsible for calling
276 * the necessary locking functions.
277 *
278 */
279 struct netlbl_af6list *netlbl_af6list_remove(const struct in6_addr *addr,
280 const struct in6_addr *mask,
281 struct list_head *head)
282 {
283 struct netlbl_af6list *entry;
284
285 entry = netlbl_af6list_search_exact(addr, mask, head);
286 if (entry == NULL)
287 return NULL;
288 netlbl_af6list_remove_entry(entry);
289 return entry;
290 }
291 #endif /* IPv6 */
292
293 /*
294 * Audit Helper Functions
295 */
296
297 #ifdef CONFIG_AUDIT
298 /**
299 * netlbl_af4list_audit_addr - Audit an IPv4 address
300 * @audit_buf: audit buffer
301 * @src: true if source address, false if destination
302 * @dev: network interface
303 * @addr: IP address
304 * @mask: IP address mask
305 *
306 * Description:
307 * Write the IPv4 address and address mask, if necessary, to @audit_buf.
308 *
309 */
310 void netlbl_af4list_audit_addr(struct audit_buffer *audit_buf,
311 int src, const char *dev,
312 __be32 addr, __be32 mask)
313 {
314 u32 mask_val = ntohl(mask);
315 char *dir = (src ? "src" : "dst");
316
317 if (dev != NULL)
318 audit_log_format(audit_buf, " netif=%s", dev);
319 audit_log_format(audit_buf, " %s=%pI4", dir, &addr);
320 if (mask_val != 0xffffffff) {
321 u32 mask_len = 0;
322 while (mask_val > 0) {
323 mask_val <<= 1;
324 mask_len++;
325 }
326 audit_log_format(audit_buf, " %s_prefixlen=%d", dir, mask_len);
327 }
328 }
329
330 #if IS_ENABLED(CONFIG_IPV6)
331 /**
332 * netlbl_af6list_audit_addr - Audit an IPv6 address
333 * @audit_buf: audit buffer
334 * @src: true if source address, false if destination
335 * @dev: network interface
336 * @addr: IP address
337 * @mask: IP address mask
338 *
339 * Description:
340 * Write the IPv6 address and address mask, if necessary, to @audit_buf.
341 *
342 */
343 void netlbl_af6list_audit_addr(struct audit_buffer *audit_buf,
344 int src,
345 const char *dev,
346 const struct in6_addr *addr,
347 const struct in6_addr *mask)
348 {
349 char *dir = (src ? "src" : "dst");
350
351 if (dev != NULL)
352 audit_log_format(audit_buf, " netif=%s", dev);
353 audit_log_format(audit_buf, " %s=%pI6", dir, addr);
354 if (ntohl(mask->s6_addr32[3]) != 0xffffffff) {
355 u32 mask_len = 0;
356 u32 mask_val;
357 int iter = -1;
358 while (ntohl(mask->s6_addr32[++iter]) == 0xffffffff)
359 mask_len += 32;
360 mask_val = ntohl(mask->s6_addr32[iter]);
361 while (mask_val > 0) {
362 mask_val <<= 1;
363 mask_len++;
364 }
365 audit_log_format(audit_buf, " %s_prefixlen=%d", dir, mask_len);
366 }
367 }
368 #endif /* IPv6 */
369 #endif /* CONFIG_AUDIT */