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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C)2002 USAGI/WIDE Project
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 *
18 * Authors
19 *
20 * Mitsuru KANDA @USAGI : IPv6 Support
21 * Kazunori MIYAZAWA @USAGI :
22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
23 *
24 * This file is derived from net/ipv4/ah.c.
25 */
26
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/module.h>
28#include <net/ip.h>
29#include <net/ah.h>
30#include <linux/crypto.h>
31#include <linux/pfkeyv2.h>
32#include <linux/string.h>
33#include <net/icmp.h>
34#include <net/ipv6.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020035#include <net/protocol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <net/xfrm.h>
37#include <asm/scatterlist.h>
38
39static int zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
40{
41 u8 *opt = (u8 *)opthdr;
42 int len = ipv6_optlen(opthdr);
43 int off = 0;
44 int optlen = 0;
45
46 off += 2;
47 len -= 2;
48
49 while (len > 0) {
50
51 switch (opt[off]) {
52
53 case IPV6_TLV_PAD0:
54 optlen = 1;
55 break;
56 default:
57 if (len < 2)
58 goto bad;
59 optlen = opt[off+1]+2;
60 if (len < optlen)
61 goto bad;
62 if (opt[off] & 0x20)
63 memset(&opt[off+2], 0, opt[off+1]);
64 break;
65 }
66
67 off += optlen;
68 len -= optlen;
69 }
70 if (len == 0)
71 return 1;
72
73bad:
74 return 0;
75}
76
Masahide NAKAMURA27637df2006-08-23 19:29:47 -070077#ifdef CONFIG_IPV6_MIP6
78/**
79 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
80 * @iph: IPv6 header
81 * @destopt: destionation options header
82 */
83static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
84{
85 u8 *opt = (u8 *)destopt;
86 int len = ipv6_optlen(destopt);
87 int off = 0;
88 int optlen = 0;
89
90 off += 2;
91 len -= 2;
92
93 while (len > 0) {
94
95 switch (opt[off]) {
96
97 case IPV6_TLV_PAD0:
98 optlen = 1;
99 break;
100 default:
101 if (len < 2)
102 goto bad;
103 optlen = opt[off+1]+2;
104 if (len < optlen)
105 goto bad;
106
107 /* Rearrange the source address in @iph and the
108 * addresses in home address option for final source.
109 * See 11.3.2 of RFC 3775 for details.
110 */
111 if (opt[off] == IPV6_TLV_HAO) {
112 struct in6_addr final_addr;
113 struct ipv6_destopt_hao *hao;
114
115 hao = (struct ipv6_destopt_hao *)&opt[off];
116 if (hao->length != sizeof(hao->addr)) {
117 if (net_ratelimit())
118 printk(KERN_WARNING "destopt hao: invalid header length: %u\n", hao->length);
119 goto bad;
120 }
121 ipv6_addr_copy(&final_addr, &hao->addr);
122 ipv6_addr_copy(&hao->addr, &iph->saddr);
123 ipv6_addr_copy(&iph->saddr, &final_addr);
124 }
125 break;
126 }
127
128 off += optlen;
129 len -= optlen;
130 }
YOSHIFUJI Hideakie731c242006-08-24 23:18:12 +0900131 /* Note: ok if len == 0 */
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700132bad:
133 return;
134}
135#endif
136
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137/**
138 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
139 * @iph: IPv6 header
140 * @rthdr: routing header
141 *
142 * Rearrange the destination address in @iph and the addresses in @rthdr
143 * so that they appear in the order they will at the final destination.
144 * See Appendix A2 of RFC 2402 for details.
145 */
146static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
147{
148 int segments, segments_left;
149 struct in6_addr *addrs;
150 struct in6_addr final_addr;
151
152 segments_left = rthdr->segments_left;
153 if (segments_left == 0)
154 return;
155 rthdr->segments_left = 0;
156
157 /* The value of rthdr->hdrlen has been verified either by the system
158 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
159 * packets. So we can assume that it is even and that segments is
160 * greater than or equal to segments_left.
161 *
162 * For the same reason we can assume that this option is of type 0.
163 */
164 segments = rthdr->hdrlen >> 1;
165
166 addrs = ((struct rt0_hdr *)rthdr)->addr;
167 ipv6_addr_copy(&final_addr, addrs + segments - 1);
168
169 addrs += segments - segments_left;
170 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
171
172 ipv6_addr_copy(addrs, &iph->daddr);
173 ipv6_addr_copy(&iph->daddr, &final_addr);
174}
175
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700176static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177{
178 union {
179 struct ipv6hdr *iph;
180 struct ipv6_opt_hdr *opth;
181 struct ipv6_rt_hdr *rth;
182 char *raw;
183 } exthdr = { .iph = iph };
184 char *end = exthdr.raw + len;
185 int nexthdr = iph->nexthdr;
186
187 exthdr.iph++;
188
189 while (exthdr.raw < end) {
190 switch (nexthdr) {
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700191 case NEXTHDR_DEST:
YOSHIFUJI Hideakie731c242006-08-24 23:18:12 +0900192#ifdef CONFIG_IPV6_MIP6
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700193 if (dir == XFRM_POLICY_OUT)
194 ipv6_rearrange_destopt(iph, exthdr.opth);
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700195#endif
YOSHIFUJI Hideakie731c242006-08-24 23:18:12 +0900196 case NEXTHDR_HOP:
197 if (!zero_out_mutable_opts(exthdr.opth)) {
198 LIMIT_NETDEBUG(
199 KERN_WARNING "overrun %sopts\n",
200 nexthdr == NEXTHDR_HOP ?
201 "hop" : "dest");
202 return -EINVAL;
203 }
204 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205
206 case NEXTHDR_ROUTING:
207 ipv6_rearrange_rthdr(iph, exthdr.rth);
208 break;
209
210 default :
211 return 0;
212 }
213
214 nexthdr = exthdr.opth->nexthdr;
215 exthdr.raw += ipv6_optlen(exthdr.opth);
216 }
217
218 return 0;
219}
220
221static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
222{
223 int err;
224 int extlen;
225 struct ipv6hdr *top_iph;
226 struct ip_auth_hdr *ah;
227 struct ah_data *ahp;
228 u8 nexthdr;
229 char tmp_base[8];
230 struct {
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700231#ifdef CONFIG_IPV6_MIP6
232 struct in6_addr saddr;
233#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 struct in6_addr daddr;
235 char hdrs[0];
236 } *tmp_ext;
237
238 top_iph = (struct ipv6hdr *)skb->data;
239 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
240
241 nexthdr = *skb->nh.raw;
242 *skb->nh.raw = IPPROTO_AH;
243
244 /* When there are no extension headers, we only need to save the first
245 * 8 bytes of the base IP header.
246 */
247 memcpy(tmp_base, top_iph, sizeof(tmp_base));
248
249 tmp_ext = NULL;
250 extlen = skb->h.raw - (unsigned char *)(top_iph + 1);
251 if (extlen) {
252 extlen += sizeof(*tmp_ext);
253 tmp_ext = kmalloc(extlen, GFP_ATOMIC);
254 if (!tmp_ext) {
255 err = -ENOMEM;
256 goto error;
257 }
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700258#ifdef CONFIG_IPV6_MIP6
259 memcpy(tmp_ext, &top_iph->saddr, extlen);
YOSHIFUJI Hideakie731c242006-08-24 23:18:12 +0900260#else
261 memcpy(tmp_ext, &top_iph->daddr, extlen);
262#endif
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700263 err = ipv6_clear_mutable_options(top_iph,
264 extlen - sizeof(*tmp_ext) +
265 sizeof(*top_iph),
266 XFRM_POLICY_OUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 if (err)
268 goto error_free_iph;
269 }
270
271 ah = (struct ip_auth_hdr *)skb->h.raw;
272 ah->nexthdr = nexthdr;
273
274 top_iph->priority = 0;
275 top_iph->flow_lbl[0] = 0;
276 top_iph->flow_lbl[1] = 0;
277 top_iph->flow_lbl[2] = 0;
278 top_iph->hop_limit = 0;
279
280 ahp = x->data;
281 ah->hdrlen = (XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) +
282 ahp->icv_trunc_len) >> 2) - 2;
283
284 ah->reserved = 0;
285 ah->spi = x->id.spi;
286 ah->seq_no = htonl(++x->replay.oseq);
Jamal Hadi Salim9500e8a2006-03-20 19:15:29 -0800287 xfrm_aevent_doreplay(x);
Herbert Xu07d4ee52006-08-20 14:24:50 +1000288 err = ah_mac_digest(ahp, skb, ah->auth_data);
289 if (err)
290 goto error_free_iph;
291 memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292
293 err = 0;
294
295 memcpy(top_iph, tmp_base, sizeof(tmp_base));
296 if (tmp_ext) {
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700297#ifdef CONFIG_IPV6_MIP6
298 memcpy(&top_iph->saddr, tmp_ext, extlen);
299#else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 memcpy(&top_iph->daddr, tmp_ext, extlen);
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700301#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302error_free_iph:
303 kfree(tmp_ext);
304 }
305
306error:
307 return err;
308}
309
Herbert Xue6956332006-04-01 00:52:46 -0800310static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311{
312 /*
313 * Before process AH
314 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
315 * |<-------------->| hdr_len
316 *
317 * To erase AH:
318 * Keeping copy of cleared headers. After AH processing,
319 * Moving the pointer of skb->nh.raw by using skb_pull as long as AH
320 * header length. Then copy back the copy as long as hdr_len
321 * If destination header following AH exists, copy it into after [Ext2].
322 *
323 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
324 * There is offset of AH before IPv6 header after the process.
325 */
326
327 struct ipv6_auth_hdr *ah;
328 struct ah_data *ahp;
329 unsigned char *tmp_hdr = NULL;
330 u16 hdr_len;
331 u16 ah_hlen;
332 int nexthdr;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000333 int err = -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334
335 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
336 goto out;
337
338 /* We are going to _remove_ AH header to keep sockets happy,
339 * so... Later this can change. */
340 if (skb_cloned(skb) &&
341 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
342 goto out;
343
344 hdr_len = skb->data - skb->nh.raw;
345 ah = (struct ipv6_auth_hdr*)skb->data;
346 ahp = x->data;
347 nexthdr = ah->nexthdr;
348 ah_hlen = (ah->hdrlen + 2) << 2;
349
350 if (ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_full_len) &&
351 ah_hlen != XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len))
352 goto out;
353
354 if (!pskb_may_pull(skb, ah_hlen))
355 goto out;
356
357 tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
358 if (!tmp_hdr)
359 goto out;
360 memcpy(tmp_hdr, skb->nh.raw, hdr_len);
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700361 if (ipv6_clear_mutable_options(skb->nh.ipv6h, hdr_len, XFRM_POLICY_IN))
362 goto free_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 skb->nh.ipv6h->priority = 0;
364 skb->nh.ipv6h->flow_lbl[0] = 0;
365 skb->nh.ipv6h->flow_lbl[1] = 0;
366 skb->nh.ipv6h->flow_lbl[2] = 0;
367 skb->nh.ipv6h->hop_limit = 0;
368
369 {
370 u8 auth_data[MAX_AH_AUTH_LEN];
371
372 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
373 memset(ah->auth_data, 0, ahp->icv_trunc_len);
Herbert Xu31a4ab92006-05-27 23:06:13 -0700374 skb_push(skb, hdr_len);
Herbert Xu07d4ee52006-08-20 14:24:50 +1000375 err = ah_mac_digest(ahp, skb, ah->auth_data);
376 if (err)
377 goto free_out;
378 err = -EINVAL;
379 if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len)) {
Patrick McHardy64ce2072005-08-09 20:50:53 -0700380 LIMIT_NETDEBUG(KERN_WARNING "ipsec ah authentication error\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 x->stats.integrity_failed++;
382 goto free_out;
383 }
384 }
385
Herbert Xu31a4ab92006-05-27 23:06:13 -0700386 skb->h.raw = memcpy(skb->nh.raw += ah_hlen, tmp_hdr, hdr_len);
387 __skb_pull(skb, ah_hlen + hdr_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388
389 kfree(tmp_hdr);
390
391 return nexthdr;
392
393free_out:
394 kfree(tmp_hdr);
395out:
Herbert Xu07d4ee52006-08-20 14:24:50 +1000396 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397}
398
399static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
400 int type, int code, int offset, __u32 info)
401{
402 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
403 struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+offset);
404 struct xfrm_state *x;
405
406 if (type != ICMPV6_DEST_UNREACH &&
407 type != ICMPV6_PKT_TOOBIG)
408 return;
409
410 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
411 if (!x)
412 return;
413
Joe Perches46b86a22006-01-13 14:29:07 -0800414 NETDEBUG(KERN_DEBUG "pmtu discovery on SA AH/%08x/" NIP6_FMT "\n",
Patrick McHardy64ce2072005-08-09 20:50:53 -0700415 ntohl(ah->spi), NIP6(iph->daddr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416
417 xfrm_state_put(x);
418}
419
Herbert Xu72cb6962005-06-20 13:18:08 -0700420static int ah6_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421{
422 struct ah_data *ahp = NULL;
423 struct xfrm_algo_desc *aalg_desc;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000424 struct crypto_hash *tfm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
426 if (!x->aalg)
427 goto error;
428
429 /* null auth can use a zero length key */
430 if (x->aalg->alg_key_len > 512)
431 goto error;
432
433 if (x->encap)
434 goto error;
435
Ingo Oeser0c600ed2006-03-20 23:01:32 -0800436 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 if (ahp == NULL)
438 return -ENOMEM;
439
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 ahp->key = x->aalg->alg_key;
441 ahp->key_len = (x->aalg->alg_key_len+7)/8;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000442 tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
443 if (IS_ERR(tfm))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 goto error;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000445
446 ahp->tfm = tfm;
447 if (crypto_hash_setkey(tfm, ahp->key, ahp->key_len))
448 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449
450 /*
451 * Lookup the algorithm description maintained by xfrm_algo,
452 * verify crypto transform properties, and store information
453 * we need for AH processing. This lookup cannot fail here
Herbert Xu07d4ee52006-08-20 14:24:50 +1000454 * after a successful crypto_alloc_hash().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 */
456 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
457 BUG_ON(!aalg_desc);
458
459 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
Herbert Xu07d4ee52006-08-20 14:24:50 +1000460 crypto_hash_digestsize(tfm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
Herbert Xu07d4ee52006-08-20 14:24:50 +1000462 x->aalg->alg_name, crypto_hash_digestsize(tfm),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 aalg_desc->uinfo.auth.icv_fullbits/8);
464 goto error;
465 }
466
467 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
468 ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
469
470 BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
471
472 ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
473 if (!ahp->work_icv)
474 goto error;
475
476 x->props.header_len = XFRM_ALIGN8(sizeof(struct ipv6_auth_hdr) + ahp->icv_trunc_len);
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700477 if (x->props.mode == XFRM_MODE_TUNNEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 x->props.header_len += sizeof(struct ipv6hdr);
479 x->data = ahp;
480
481 return 0;
482
483error:
484 if (ahp) {
Jesper Juhl573dbd92005-09-01 17:44:29 -0700485 kfree(ahp->work_icv);
Herbert Xu07d4ee52006-08-20 14:24:50 +1000486 crypto_free_hash(ahp->tfm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 kfree(ahp);
488 }
489 return -EINVAL;
490}
491
492static void ah6_destroy(struct xfrm_state *x)
493{
494 struct ah_data *ahp = x->data;
495
496 if (!ahp)
497 return;
498
Jesper Juhl573dbd92005-09-01 17:44:29 -0700499 kfree(ahp->work_icv);
500 ahp->work_icv = NULL;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000501 crypto_free_hash(ahp->tfm);
Jesper Juhl573dbd92005-09-01 17:44:29 -0700502 ahp->tfm = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 kfree(ahp);
504}
505
506static struct xfrm_type ah6_type =
507{
508 .description = "AH6",
509 .owner = THIS_MODULE,
510 .proto = IPPROTO_AH,
511 .init_state = ah6_init_state,
512 .destructor = ah6_destroy,
513 .input = ah6_input,
Masahide NAKAMURAaee5adb2006-08-23 17:57:28 -0700514 .output = ah6_output,
515 .hdr_offset = xfrm6_find_1stfragopt,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516};
517
518static struct inet6_protocol ah6_protocol = {
519 .handler = xfrm6_rcv,
520 .err_handler = ah6_err,
521 .flags = INET6_PROTO_NOPOLICY,
522};
523
524static int __init ah6_init(void)
525{
526 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
527 printk(KERN_INFO "ipv6 ah init: can't add xfrm type\n");
528 return -EAGAIN;
529 }
530
531 if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
532 printk(KERN_INFO "ipv6 ah init: can't add protocol\n");
533 xfrm_unregister_type(&ah6_type, AF_INET6);
534 return -EAGAIN;
535 }
536
537 return 0;
538}
539
540static void __exit ah6_fini(void)
541{
542 if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
543 printk(KERN_INFO "ipv6 ah close: can't remove protocol\n");
544
545 if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
546 printk(KERN_INFO "ipv6 ah close: can't remove xfrm type\n");
547
548}
549
550module_init(ah6_init);
551module_exit(ah6_fini);
552
553MODULE_LICENSE("GPL");