1/*
2 * NetLabel Kernel API
3 *
4 * This file defines the kernel API for the NetLabel system.  The NetLabel
5 * system manages static and dynamic label mappings for network protocols such
6 * as CIPSO and RIPSO.
7 *
8 * Author: Paul Moore <paul.moore@hp.com>
9 *
10 */
11
12/*
13 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
14 *
15 * This program is free software;  you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY;  without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
23 * the GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with this program;  if not, write to the Free Software
27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 *
29 */
30
31#include <linux/init.h>
32#include <linux/types.h>
33#include <net/ip.h>
34#include <net/netlabel.h>
35#include <net/cipso_ipv4.h>
36#include <asm/bug.h>
37
38#include "netlabel_domainhash.h"
39#include "netlabel_unlabeled.h"
40#include "netlabel_user.h"
41
42/*
43 * Security Attribute Functions
44 */
45
46/**
47 * netlbl_secattr_catmap_walk - Walk a LSM secattr catmap looking for a bit
48 * @catmap: the category bitmap
49 * @offset: the offset to start searching at, in bits
50 *
51 * Description:
52 * This function walks a LSM secattr category bitmap starting at @offset and
53 * returns the spot of the first set bit or -ENOENT if no bits are set.
54 *
55 */
56int netlbl_secattr_catmap_walk(struct netlbl_lsm_secattr_catmap *catmap,
57			       u32 offset)
58{
59	struct netlbl_lsm_secattr_catmap *iter = catmap;
60	u32 node_idx;
61	u32 node_bit;
62	NETLBL_CATMAP_MAPTYPE bitmap;
63
64	if (offset > iter->startbit) {
65		while (offset >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
66			iter = iter->next;
67			if (iter == NULL)
68				return -ENOENT;
69		}
70		node_idx = (offset - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
71		node_bit = offset - iter->startbit -
72			   (NETLBL_CATMAP_MAPSIZE * node_idx);
73	} else {
74		node_idx = 0;
75		node_bit = 0;
76	}
77	bitmap = iter->bitmap[node_idx] >> node_bit;
78
79	for (;;) {
80		if (bitmap != 0) {
81			while ((bitmap & NETLBL_CATMAP_BIT) == 0) {
82				bitmap >>= 1;
83				node_bit++;
84			}
85			return iter->startbit +
86				(NETLBL_CATMAP_MAPSIZE * node_idx) + node_bit;
87		}
88		if (++node_idx >= NETLBL_CATMAP_MAPCNT) {
89			if (iter->next != NULL) {
90				iter = iter->next;
91				node_idx = 0;
92			} else
93				return -ENOENT;
94		}
95		bitmap = iter->bitmap[node_idx];
96		node_bit = 0;
97	}
98
99	return -ENOENT;
100}
101
102/**
103 * netlbl_secattr_catmap_walk_rng - Find the end of a string of set bits
104 * @catmap: the category bitmap
105 * @offset: the offset to start searching at, in bits
106 *
107 * Description:
108 * This function walks a LSM secattr category bitmap starting at @offset and
109 * returns the spot of the first cleared bit or -ENOENT if the offset is past
110 * the end of the bitmap.
111 *
112 */
113int netlbl_secattr_catmap_walk_rng(struct netlbl_lsm_secattr_catmap *catmap,
114				   u32 offset)
115{
116	struct netlbl_lsm_secattr_catmap *iter = catmap;
117	u32 node_idx;
118	u32 node_bit;
119	NETLBL_CATMAP_MAPTYPE bitmask;
120	NETLBL_CATMAP_MAPTYPE bitmap;
121
122	if (offset > iter->startbit) {
123		while (offset >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
124			iter = iter->next;
125			if (iter == NULL)
126				return -ENOENT;
127		}
128		node_idx = (offset - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
129		node_bit = offset - iter->startbit -
130			   (NETLBL_CATMAP_MAPSIZE * node_idx);
131	} else {
132		node_idx = 0;
133		node_bit = 0;
134	}
135	bitmask = NETLBL_CATMAP_BIT << node_bit;
136
137	for (;;) {
138		bitmap = iter->bitmap[node_idx];
139		while (bitmask != 0 && (bitmap & bitmask) != 0) {
140			bitmask <<= 1;
141			node_bit++;
142		}
143
144		if (bitmask != 0)
145			return iter->startbit +
146				(NETLBL_CATMAP_MAPSIZE * node_idx) +
147				node_bit - 1;
148		else if (++node_idx >= NETLBL_CATMAP_MAPCNT) {
149			if (iter->next == NULL)
150				return iter->startbit +	NETLBL_CATMAP_SIZE - 1;
151			iter = iter->next;
152			node_idx = 0;
153		}
154		bitmask = NETLBL_CATMAP_BIT;
155		node_bit = 0;
156	}
157
158	return -ENOENT;
159}
160
161/**
162 * netlbl_secattr_catmap_setbit - Set a bit in a LSM secattr catmap
163 * @catmap: the category bitmap
164 * @bit: the bit to set
165 * @flags: memory allocation flags
166 *
167 * Description:
168 * Set the bit specified by @bit in @catmap.  Returns zero on success,
169 * negative values on failure.
170 *
171 */
172int netlbl_secattr_catmap_setbit(struct netlbl_lsm_secattr_catmap *catmap,
173				 u32 bit,
174				 gfp_t flags)
175{
176	struct netlbl_lsm_secattr_catmap *iter = catmap;
177	u32 node_bit;
178	u32 node_idx;
179
180	while (iter->next != NULL &&
181	       bit >= (iter->startbit + NETLBL_CATMAP_SIZE))
182		iter = iter->next;
183	if (bit >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
184		iter->next = netlbl_secattr_catmap_alloc(flags);
185		if (iter->next == NULL)
186			return -ENOMEM;
187		iter = iter->next;
188		iter->startbit = bit & ~(NETLBL_CATMAP_SIZE - 1);
189	}
190
191	/* gcc always rounds to zero when doing integer division */
192	node_idx = (bit - iter->startbit) / NETLBL_CATMAP_MAPSIZE;
193	node_bit = bit - iter->startbit - (NETLBL_CATMAP_MAPSIZE * node_idx);
194	iter->bitmap[node_idx] |= NETLBL_CATMAP_BIT << node_bit;
195
196	return 0;
197}
198
199/**
200 * netlbl_secattr_catmap_setrng - Set a range of bits in a LSM secattr catmap
201 * @catmap: the category bitmap
202 * @start: the starting bit
203 * @end: the last bit in the string
204 * @flags: memory allocation flags
205 *
206 * Description:
207 * Set a range of bits, starting at @start and ending with @end.  Returns zero
208 * on success, negative values on failure.
209 *
210 */
211int netlbl_secattr_catmap_setrng(struct netlbl_lsm_secattr_catmap *catmap,
212				 u32 start,
213				 u32 end,
214				 gfp_t flags)
215{
216	int ret_val = 0;
217	struct netlbl_lsm_secattr_catmap *iter = catmap;
218	u32 iter_max_spot;
219	u32 spot;
220
221
222	while (iter->next != NULL &&
223	       start >= (iter->startbit + NETLBL_CATMAP_SIZE))
224		iter = iter->next;
225	iter_max_spot = iter->startbit + NETLBL_CATMAP_SIZE;
226
227	for (spot = start; spot <= end && ret_val == 0; spot++) {
228		if (spot >= iter_max_spot && iter->next != NULL) {
229			iter = iter->next;
230			iter_max_spot = iter->startbit + NETLBL_CATMAP_SIZE;
231		}
232		ret_val = netlbl_secattr_catmap_setbit(iter, spot, GFP_ATOMIC);
233	}
234
235	return ret_val;
236}
237
238/*
239 * LSM Functions
240 */
241
242/**
243 * netlbl_socket_setattr - Label a socket using the correct protocol
244 * @sk: the socket to label
245 * @secattr: the security attributes
246 *
247 * Description:
248 * Attach the correct label to the given socket using the security attributes
249 * specified in @secattr.  This function requires exclusive access to @sk,
250 * which means it either needs to be in the process of being created or locked.
251 * Returns zero on success, negative values on failure.
252 *
253 */
254int netlbl_sock_setattr(struct sock *sk,
255			const struct netlbl_lsm_secattr *secattr)
256{
257	int ret_val = -ENOENT;
258	struct netlbl_dom_map *dom_entry;
259
260	rcu_read_lock();
261	dom_entry = netlbl_domhsh_getentry(secattr->domain);
262	if (dom_entry == NULL)
263		goto socket_setattr_return;
264	switch (dom_entry->type) {
265	case NETLBL_NLTYPE_CIPSOV4:
266		ret_val = cipso_v4_sock_setattr(sk,
267						dom_entry->type_def.cipsov4,
268						secattr);
269		break;
270	case NETLBL_NLTYPE_UNLABELED:
271		ret_val = 0;
272		break;
273	default:
274		ret_val = -ENOENT;
275	}
276
277socket_setattr_return:
278	rcu_read_unlock();
279	return ret_val;
280}
281
282/**
283 * netlbl_sock_getattr - Determine the security attributes of a sock
284 * @sk: the sock
285 * @secattr: the security attributes
286 *
287 * Description:
288 * Examines the given sock to see any NetLabel style labeling has been
289 * applied to the sock, if so it parses the socket label and returns the
290 * security attributes in @secattr.  Returns zero on success, negative values
291 * on failure.
292 *
293 */
294int netlbl_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
295{
296	int ret_val;
297
298	ret_val = cipso_v4_sock_getattr(sk, secattr);
299	if (ret_val == 0)
300		return 0;
301
302	return netlbl_unlabel_getattr(secattr);
303}
304
305/**
306 * netlbl_skbuff_getattr - Determine the security attributes of a packet
307 * @skb: the packet
308 * @secattr: the security attributes
309 *
310 * Description:
311 * Examines the given packet to see if a recognized form of packet labeling
312 * is present, if so it parses the packet label and returns the security
313 * attributes in @secattr.  Returns zero on success, negative values on
314 * failure.
315 *
316 */
317int netlbl_skbuff_getattr(const struct sk_buff *skb,
318			  struct netlbl_lsm_secattr *secattr)
319{
320	if (CIPSO_V4_OPTEXIST(skb) &&
321	    cipso_v4_skbuff_getattr(skb, secattr) == 0)
322		return 0;
323
324	return netlbl_unlabel_getattr(secattr);
325}
326
327/**
328 * netlbl_skbuff_err - Handle a LSM error on a sk_buff
329 * @skb: the packet
330 * @error: the error code
331 *
332 * Description:
333 * Deal with a LSM problem when handling the packet in @skb, typically this is
334 * a permission denied problem (-EACCES).  The correct action is determined
335 * according to the packet's labeling protocol.
336 *
337 */
338void netlbl_skbuff_err(struct sk_buff *skb, int error)
339{
340	if (CIPSO_V4_OPTEXIST(skb))
341		cipso_v4_error(skb, error, 0);
342}
343
344/**
345 * netlbl_cache_invalidate - Invalidate all of the NetLabel protocol caches
346 *
347 * Description:
348 * For all of the NetLabel protocols that support some form of label mapping
349 * cache, invalidate the cache.  Returns zero on success, negative values on
350 * error.
351 *
352 */
353void netlbl_cache_invalidate(void)
354{
355	cipso_v4_cache_invalidate();
356}
357
358/**
359 * netlbl_cache_add - Add an entry to a NetLabel protocol cache
360 * @skb: the packet
361 * @secattr: the packet's security attributes
362 *
363 * Description:
364 * Add the LSM security attributes for the given packet to the underlying
365 * NetLabel protocol's label mapping cache.  Returns zero on success, negative
366 * values on error.
367 *
368 */
369int netlbl_cache_add(const struct sk_buff *skb,
370		     const struct netlbl_lsm_secattr *secattr)
371{
372	if ((secattr->flags & NETLBL_SECATTR_CACHE) == 0)
373		return -ENOMSG;
374
375	if (CIPSO_V4_OPTEXIST(skb))
376		return cipso_v4_cache_add(skb, secattr);
377
378	return -ENOMSG;
379}
380
381/*
382 * Setup Functions
383 */
384
385/**
386 * netlbl_init - Initialize NetLabel
387 *
388 * Description:
389 * Perform the required NetLabel initialization before first use.
390 *
391 */
392static int __init netlbl_init(void)
393{
394	int ret_val;
395
396	printk(KERN_INFO "NetLabel: Initializing\n");
397	printk(KERN_INFO "NetLabel:  domain hash size = %u\n",
398	       (1 << NETLBL_DOMHSH_BITSIZE));
399	printk(KERN_INFO "NetLabel:  protocols ="
400	       " UNLABELED"
401	       " CIPSOv4"
402	       "\n");
403
404	ret_val = netlbl_domhsh_init(NETLBL_DOMHSH_BITSIZE);
405	if (ret_val != 0)
406		goto init_failure;
407
408	ret_val = netlbl_netlink_init();
409	if (ret_val != 0)
410		goto init_failure;
411
412	ret_val = netlbl_unlabel_defconf();
413	if (ret_val != 0)
414		goto init_failure;
415	printk(KERN_INFO "NetLabel:  unlabeled traffic allowed by default\n");
416
417	return 0;
418
419init_failure:
420	panic("NetLabel: failed to initialize properly (%d)\n", ret_val);
421}
422
423subsys_initcall(netlbl_init);
424