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 */
60struct 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 */
84struct 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 */
110struct 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 */
135struct 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 */
162int 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 */
199int 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 */
235void 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 */
253struct 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 */
275void 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 */
293struct 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 */
324void 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 */
357void 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