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1/*
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
27#include <crypto/hash.h>
28#include <linux/module.h>
29#include <linux/slab.h>
30#include <net/ip.h>
31#include <net/ah.h>
32#include <linux/crypto.h>
33#include <linux/pfkeyv2.h>
34#include <linux/string.h>
35#include <linux/scatterlist.h>
36#include <net/icmp.h>
37#include <net/ipv6.h>
38#include <net/protocol.h>
39#include <net/xfrm.h>
40
41#define IPV6HDR_BASELEN 8
42
43struct tmp_ext {
44#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
45 struct in6_addr saddr;
46#endif
47 struct in6_addr daddr;
48 char hdrs[0];
49};
50
51struct ah_skb_cb {
52 struct xfrm_skb_cb xfrm;
53 void *tmp;
54};
55
56#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
57
58static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
59 unsigned int size)
60{
61 unsigned int len;
62
63 len = size + crypto_ahash_digestsize(ahash) +
64 (crypto_ahash_alignmask(ahash) &
65 ~(crypto_tfm_ctx_alignment() - 1));
66
67 len = ALIGN(len, crypto_tfm_ctx_alignment());
68
69 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
70 len = ALIGN(len, __alignof__(struct scatterlist));
71
72 len += sizeof(struct scatterlist) * nfrags;
73
74 return kmalloc(len, GFP_ATOMIC);
75}
76
77static inline struct tmp_ext *ah_tmp_ext(void *base)
78{
79 return base + IPV6HDR_BASELEN;
80}
81
82static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
83{
84 return tmp + offset;
85}
86
87static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
88 unsigned int offset)
89{
90 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
91}
92
93static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
94 u8 *icv)
95{
96 struct ahash_request *req;
97
98 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
99 crypto_tfm_ctx_alignment());
100
101 ahash_request_set_tfm(req, ahash);
102
103 return req;
104}
105
106static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
107 struct ahash_request *req)
108{
109 return (void *)ALIGN((unsigned long)(req + 1) +
110 crypto_ahash_reqsize(ahash),
111 __alignof__(struct scatterlist));
112}
113
114static int zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
115{
116 u8 *opt = (u8 *)opthdr;
117 int len = ipv6_optlen(opthdr);
118 int off = 0;
119 int optlen = 0;
120
121 off += 2;
122 len -= 2;
123
124 while (len > 0) {
125
126 switch (opt[off]) {
127
128 case IPV6_TLV_PAD0:
129 optlen = 1;
130 break;
131 default:
132 if (len < 2)
133 goto bad;
134 optlen = opt[off+1]+2;
135 if (len < optlen)
136 goto bad;
137 if (opt[off] & 0x20)
138 memset(&opt[off+2], 0, opt[off+1]);
139 break;
140 }
141
142 off += optlen;
143 len -= optlen;
144 }
145 if (len == 0)
146 return 1;
147
148bad:
149 return 0;
150}
151
152#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
153/**
154 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
155 * @iph: IPv6 header
156 * @destopt: destionation options header
157 */
158static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
159{
160 u8 *opt = (u8 *)destopt;
161 int len = ipv6_optlen(destopt);
162 int off = 0;
163 int optlen = 0;
164
165 off += 2;
166 len -= 2;
167
168 while (len > 0) {
169
170 switch (opt[off]) {
171
172 case IPV6_TLV_PAD0:
173 optlen = 1;
174 break;
175 default:
176 if (len < 2)
177 goto bad;
178 optlen = opt[off+1]+2;
179 if (len < optlen)
180 goto bad;
181
182 /* Rearrange the source address in @iph and the
183 * addresses in home address option for final source.
184 * See 11.3.2 of RFC 3775 for details.
185 */
186 if (opt[off] == IPV6_TLV_HAO) {
187 struct in6_addr final_addr;
188 struct ipv6_destopt_hao *hao;
189
190 hao = (struct ipv6_destopt_hao *)&opt[off];
191 if (hao->length != sizeof(hao->addr)) {
192 if (net_ratelimit())
193 printk(KERN_WARNING "destopt hao: invalid header length: %u\n", hao->length);
194 goto bad;
195 }
196 ipv6_addr_copy(&final_addr, &hao->addr);
197 ipv6_addr_copy(&hao->addr, &iph->saddr);
198 ipv6_addr_copy(&iph->saddr, &final_addr);
199 }
200 break;
201 }
202
203 off += optlen;
204 len -= optlen;
205 }
206 /* Note: ok if len == 0 */
207bad:
208 return;
209}
210#else
211static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
212#endif
213
214/**
215 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
216 * @iph: IPv6 header
217 * @rthdr: routing header
218 *
219 * Rearrange the destination address in @iph and the addresses in @rthdr
220 * so that they appear in the order they will at the final destination.
221 * See Appendix A2 of RFC 2402 for details.
222 */
223static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
224{
225 int segments, segments_left;
226 struct in6_addr *addrs;
227 struct in6_addr final_addr;
228
229 segments_left = rthdr->segments_left;
230 if (segments_left == 0)
231 return;
232 rthdr->segments_left = 0;
233
234 /* The value of rthdr->hdrlen has been verified either by the system
235 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
236 * packets. So we can assume that it is even and that segments is
237 * greater than or equal to segments_left.
238 *
239 * For the same reason we can assume that this option is of type 0.
240 */
241 segments = rthdr->hdrlen >> 1;
242
243 addrs = ((struct rt0_hdr *)rthdr)->addr;
244 ipv6_addr_copy(&final_addr, addrs + segments - 1);
245
246 addrs += segments - segments_left;
247 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
248
249 ipv6_addr_copy(addrs, &iph->daddr);
250 ipv6_addr_copy(&iph->daddr, &final_addr);
251}
252
253static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
254{
255 union {
256 struct ipv6hdr *iph;
257 struct ipv6_opt_hdr *opth;
258 struct ipv6_rt_hdr *rth;
259 char *raw;
260 } exthdr = { .iph = iph };
261 char *end = exthdr.raw + len;
262 int nexthdr = iph->nexthdr;
263
264 exthdr.iph++;
265
266 while (exthdr.raw < end) {
267 switch (nexthdr) {
268 case NEXTHDR_DEST:
269 if (dir == XFRM_POLICY_OUT)
270 ipv6_rearrange_destopt(iph, exthdr.opth);
271 case NEXTHDR_HOP:
272 if (!zero_out_mutable_opts(exthdr.opth)) {
273 LIMIT_NETDEBUG(
274 KERN_WARNING "overrun %sopts\n",
275 nexthdr == NEXTHDR_HOP ?
276 "hop" : "dest");
277 return -EINVAL;
278 }
279 break;
280
281 case NEXTHDR_ROUTING:
282 ipv6_rearrange_rthdr(iph, exthdr.rth);
283 break;
284
285 default :
286 return 0;
287 }
288
289 nexthdr = exthdr.opth->nexthdr;
290 exthdr.raw += ipv6_optlen(exthdr.opth);
291 }
292
293 return 0;
294}
295
296static void ah6_output_done(struct crypto_async_request *base, int err)
297{
298 int extlen;
299 u8 *iph_base;
300 u8 *icv;
301 struct sk_buff *skb = base->data;
302 struct xfrm_state *x = skb_dst(skb)->xfrm;
303 struct ah_data *ahp = x->data;
304 struct ipv6hdr *top_iph = ipv6_hdr(skb);
305 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
306 struct tmp_ext *iph_ext;
307
308 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
309 if (extlen)
310 extlen += sizeof(*iph_ext);
311
312 iph_base = AH_SKB_CB(skb)->tmp;
313 iph_ext = ah_tmp_ext(iph_base);
314 icv = ah_tmp_icv(ahp->ahash, iph_ext, extlen);
315
316 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
317 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
318
319 if (extlen) {
320#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
321 memcpy(&top_iph->saddr, iph_ext, extlen);
322#else
323 memcpy(&top_iph->daddr, iph_ext, extlen);
324#endif
325 }
326
327 err = ah->nexthdr;
328
329 kfree(AH_SKB_CB(skb)->tmp);
330 xfrm_output_resume(skb, err);
331}
332
333static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
334{
335 int err;
336 int nfrags;
337 int extlen;
338 u8 *iph_base;
339 u8 *icv;
340 u8 nexthdr;
341 struct sk_buff *trailer;
342 struct crypto_ahash *ahash;
343 struct ahash_request *req;
344 struct scatterlist *sg;
345 struct ipv6hdr *top_iph;
346 struct ip_auth_hdr *ah;
347 struct ah_data *ahp;
348 struct tmp_ext *iph_ext;
349
350 ahp = x->data;
351 ahash = ahp->ahash;
352
353 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
354 goto out;
355 nfrags = err;
356
357 skb_push(skb, -skb_network_offset(skb));
358 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
359 if (extlen)
360 extlen += sizeof(*iph_ext);
361
362 err = -ENOMEM;
363 iph_base = ah_alloc_tmp(ahash, nfrags, IPV6HDR_BASELEN + extlen);
364 if (!iph_base)
365 goto out;
366
367 iph_ext = ah_tmp_ext(iph_base);
368 icv = ah_tmp_icv(ahash, iph_ext, extlen);
369 req = ah_tmp_req(ahash, icv);
370 sg = ah_req_sg(ahash, req);
371
372 ah = ip_auth_hdr(skb);
373 memset(ah->auth_data, 0, ahp->icv_trunc_len);
374
375 top_iph = ipv6_hdr(skb);
376 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
377
378 nexthdr = *skb_mac_header(skb);
379 *skb_mac_header(skb) = IPPROTO_AH;
380
381 /* When there are no extension headers, we only need to save the first
382 * 8 bytes of the base IP header.
383 */
384 memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
385
386 if (extlen) {
387#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
388 memcpy(iph_ext, &top_iph->saddr, extlen);
389#else
390 memcpy(iph_ext, &top_iph->daddr, extlen);
391#endif
392 err = ipv6_clear_mutable_options(top_iph,
393 extlen - sizeof(*iph_ext) +
394 sizeof(*top_iph),
395 XFRM_POLICY_OUT);
396 if (err)
397 goto out_free;
398 }
399
400 ah->nexthdr = nexthdr;
401
402 top_iph->priority = 0;
403 top_iph->flow_lbl[0] = 0;
404 top_iph->flow_lbl[1] = 0;
405 top_iph->flow_lbl[2] = 0;
406 top_iph->hop_limit = 0;
407
408 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
409
410 ah->reserved = 0;
411 ah->spi = x->id.spi;
412 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
413
414 sg_init_table(sg, nfrags);
415 skb_to_sgvec(skb, sg, 0, skb->len);
416
417 ahash_request_set_crypt(req, sg, icv, skb->len);
418 ahash_request_set_callback(req, 0, ah6_output_done, skb);
419
420 AH_SKB_CB(skb)->tmp = iph_base;
421
422 err = crypto_ahash_digest(req);
423 if (err) {
424 if (err == -EINPROGRESS)
425 goto out;
426
427 if (err == -EBUSY)
428 err = NET_XMIT_DROP;
429 goto out_free;
430 }
431
432 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
433 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
434
435 if (extlen) {
436#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
437 memcpy(&top_iph->saddr, iph_ext, extlen);
438#else
439 memcpy(&top_iph->daddr, iph_ext, extlen);
440#endif
441 }
442
443out_free:
444 kfree(iph_base);
445out:
446 return err;
447}
448
449static void ah6_input_done(struct crypto_async_request *base, int err)
450{
451 u8 *auth_data;
452 u8 *icv;
453 u8 *work_iph;
454 struct sk_buff *skb = base->data;
455 struct xfrm_state *x = xfrm_input_state(skb);
456 struct ah_data *ahp = x->data;
457 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
458 int hdr_len = skb_network_header_len(skb);
459 int ah_hlen = (ah->hdrlen + 2) << 2;
460
461 work_iph = AH_SKB_CB(skb)->tmp;
462 auth_data = ah_tmp_auth(work_iph, hdr_len);
463 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
464
465 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
466 if (err)
467 goto out;
468
469 skb->network_header += ah_hlen;
470 memcpy(skb_network_header(skb), work_iph, hdr_len);
471 __skb_pull(skb, ah_hlen + hdr_len);
472 skb_set_transport_header(skb, -hdr_len);
473
474 err = ah->nexthdr;
475out:
476 kfree(AH_SKB_CB(skb)->tmp);
477 xfrm_input_resume(skb, err);
478}
479
480
481
482static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
483{
484 /*
485 * Before process AH
486 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
487 * |<-------------->| hdr_len
488 *
489 * To erase AH:
490 * Keeping copy of cleared headers. After AH processing,
491 * Moving the pointer of skb->network_header by using skb_pull as long
492 * as AH header length. Then copy back the copy as long as hdr_len
493 * If destination header following AH exists, copy it into after [Ext2].
494 *
495 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
496 * There is offset of AH before IPv6 header after the process.
497 */
498
499 u8 *auth_data;
500 u8 *icv;
501 u8 *work_iph;
502 struct sk_buff *trailer;
503 struct crypto_ahash *ahash;
504 struct ahash_request *req;
505 struct scatterlist *sg;
506 struct ip_auth_hdr *ah;
507 struct ipv6hdr *ip6h;
508 struct ah_data *ahp;
509 u16 hdr_len;
510 u16 ah_hlen;
511 int nexthdr;
512 int nfrags;
513 int err = -ENOMEM;
514
515 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
516 goto out;
517
518 /* We are going to _remove_ AH header to keep sockets happy,
519 * so... Later this can change. */
520 if (skb_cloned(skb) &&
521 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
522 goto out;
523
524 skb->ip_summed = CHECKSUM_NONE;
525
526 hdr_len = skb_network_header_len(skb);
527 ah = (struct ip_auth_hdr *)skb->data;
528 ahp = x->data;
529 ahash = ahp->ahash;
530
531 nexthdr = ah->nexthdr;
532 ah_hlen = (ah->hdrlen + 2) << 2;
533
534 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
535 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
536 goto out;
537
538 if (!pskb_may_pull(skb, ah_hlen))
539 goto out;
540
541
542 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
543 goto out;
544 nfrags = err;
545
546 ah = (struct ip_auth_hdr *)skb->data;
547 ip6h = ipv6_hdr(skb);
548
549 skb_push(skb, hdr_len);
550
551 work_iph = ah_alloc_tmp(ahash, nfrags, hdr_len + ahp->icv_trunc_len);
552 if (!work_iph)
553 goto out;
554
555 auth_data = ah_tmp_auth(work_iph, hdr_len);
556 icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
557 req = ah_tmp_req(ahash, icv);
558 sg = ah_req_sg(ahash, req);
559
560 memcpy(work_iph, ip6h, hdr_len);
561 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
562 memset(ah->auth_data, 0, ahp->icv_trunc_len);
563
564 if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
565 goto out_free;
566
567 ip6h->priority = 0;
568 ip6h->flow_lbl[0] = 0;
569 ip6h->flow_lbl[1] = 0;
570 ip6h->flow_lbl[2] = 0;
571 ip6h->hop_limit = 0;
572
573 sg_init_table(sg, nfrags);
574 skb_to_sgvec(skb, sg, 0, skb->len);
575
576 ahash_request_set_crypt(req, sg, icv, skb->len);
577 ahash_request_set_callback(req, 0, ah6_input_done, skb);
578
579 AH_SKB_CB(skb)->tmp = work_iph;
580
581 err = crypto_ahash_digest(req);
582 if (err) {
583 if (err == -EINPROGRESS)
584 goto out;
585
586 if (err == -EBUSY)
587 err = NET_XMIT_DROP;
588 goto out_free;
589 }
590
591 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
592 if (err)
593 goto out_free;
594
595 skb->network_header += ah_hlen;
596 memcpy(skb_network_header(skb), work_iph, hdr_len);
597 skb->transport_header = skb->network_header;
598 __skb_pull(skb, ah_hlen + hdr_len);
599
600 err = nexthdr;
601
602out_free:
603 kfree(work_iph);
604out:
605 return err;
606}
607
608static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
609 u8 type, u8 code, int offset, __be32 info)
610{
611 struct net *net = dev_net(skb->dev);
612 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
613 struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+offset);
614 struct xfrm_state *x;
615
616 if (type != ICMPV6_DEST_UNREACH &&
617 type != ICMPV6_PKT_TOOBIG)
618 return;
619
620 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
621 if (!x)
622 return;
623
624 NETDEBUG(KERN_DEBUG "pmtu discovery on SA AH/%08x/%pI6\n",
625 ntohl(ah->spi), &iph->daddr);
626
627 xfrm_state_put(x);
628}
629
630static int ah6_init_state(struct xfrm_state *x)
631{
632 struct ah_data *ahp = NULL;
633 struct xfrm_algo_desc *aalg_desc;
634 struct crypto_ahash *ahash;
635
636 if (!x->aalg)
637 goto error;
638
639 if (x->encap)
640 goto error;
641
642 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
643 if (ahp == NULL)
644 return -ENOMEM;
645
646 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
647 if (IS_ERR(ahash))
648 goto error;
649
650 ahp->ahash = ahash;
651 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
652 (x->aalg->alg_key_len + 7) / 8))
653 goto error;
654
655 /*
656 * Lookup the algorithm description maintained by xfrm_algo,
657 * verify crypto transform properties, and store information
658 * we need for AH processing. This lookup cannot fail here
659 * after a successful crypto_alloc_hash().
660 */
661 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
662 BUG_ON(!aalg_desc);
663
664 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
665 crypto_ahash_digestsize(ahash)) {
666 printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
667 x->aalg->alg_name, crypto_ahash_digestsize(ahash),
668 aalg_desc->uinfo.auth.icv_fullbits/8);
669 goto error;
670 }
671
672 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
673 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
674
675 BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
676
677 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
678 ahp->icv_trunc_len);
679 switch (x->props.mode) {
680 case XFRM_MODE_BEET:
681 case XFRM_MODE_TRANSPORT:
682 break;
683 case XFRM_MODE_TUNNEL:
684 x->props.header_len += sizeof(struct ipv6hdr);
685 break;
686 default:
687 goto error;
688 }
689 x->data = ahp;
690
691 return 0;
692
693error:
694 if (ahp) {
695 crypto_free_ahash(ahp->ahash);
696 kfree(ahp);
697 }
698 return -EINVAL;
699}
700
701static void ah6_destroy(struct xfrm_state *x)
702{
703 struct ah_data *ahp = x->data;
704
705 if (!ahp)
706 return;
707
708 crypto_free_ahash(ahp->ahash);
709 kfree(ahp);
710}
711
712static const struct xfrm_type ah6_type =
713{
714 .description = "AH6",
715 .owner = THIS_MODULE,
716 .proto = IPPROTO_AH,
717 .flags = XFRM_TYPE_REPLAY_PROT,
718 .init_state = ah6_init_state,
719 .destructor = ah6_destroy,
720 .input = ah6_input,
721 .output = ah6_output,
722 .hdr_offset = xfrm6_find_1stfragopt,
723};
724
725static const struct inet6_protocol ah6_protocol = {
726 .handler = xfrm6_rcv,
727 .err_handler = ah6_err,
728 .flags = INET6_PROTO_NOPOLICY,
729};
730
731static int __init ah6_init(void)
732{
733 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
734 printk(KERN_INFO "ipv6 ah init: can't add xfrm type\n");
735 return -EAGAIN;
736 }
737
738 if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
739 printk(KERN_INFO "ipv6 ah init: can't add protocol\n");
740 xfrm_unregister_type(&ah6_type, AF_INET6);
741 return -EAGAIN;
742 }
743
744 return 0;
745}
746
747static void __exit ah6_fini(void)
748{
749 if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
750 printk(KERN_INFO "ipv6 ah close: can't remove protocol\n");
751
752 if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
753 printk(KERN_INFO "ipv6 ah close: can't remove xfrm type\n");
754
755}
756
757module_init(ah6_init);
758module_exit(ah6_fini);
759
760MODULE_LICENSE("GPL");
761MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);
1/*
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, see <http://www.gnu.org/licenses/>.
16 *
17 * Authors
18 *
19 * Mitsuru KANDA @USAGI : IPv6 Support
20 * Kazunori MIYAZAWA @USAGI :
21 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
22 *
23 * This file is derived from net/ipv4/ah.c.
24 */
25
26#define pr_fmt(fmt) "IPv6: " fmt
27
28#include <crypto/algapi.h>
29#include <crypto/hash.h>
30#include <linux/module.h>
31#include <linux/slab.h>
32#include <net/ip.h>
33#include <net/ah.h>
34#include <linux/crypto.h>
35#include <linux/pfkeyv2.h>
36#include <linux/string.h>
37#include <linux/scatterlist.h>
38#include <net/ip6_route.h>
39#include <net/icmp.h>
40#include <net/ipv6.h>
41#include <net/protocol.h>
42#include <net/xfrm.h>
43
44#define IPV6HDR_BASELEN 8
45
46struct tmp_ext {
47#if IS_ENABLED(CONFIG_IPV6_MIP6)
48 struct in6_addr saddr;
49#endif
50 struct in6_addr daddr;
51 char hdrs[0];
52};
53
54struct ah_skb_cb {
55 struct xfrm_skb_cb xfrm;
56 void *tmp;
57};
58
59#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
60
61static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
62 unsigned int size)
63{
64 unsigned int len;
65
66 len = size + crypto_ahash_digestsize(ahash) +
67 (crypto_ahash_alignmask(ahash) &
68 ~(crypto_tfm_ctx_alignment() - 1));
69
70 len = ALIGN(len, crypto_tfm_ctx_alignment());
71
72 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
73 len = ALIGN(len, __alignof__(struct scatterlist));
74
75 len += sizeof(struct scatterlist) * nfrags;
76
77 return kmalloc(len, GFP_ATOMIC);
78}
79
80static inline struct tmp_ext *ah_tmp_ext(void *base)
81{
82 return base + IPV6HDR_BASELEN;
83}
84
85static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
86{
87 return tmp + offset;
88}
89
90static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
91 unsigned int offset)
92{
93 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
94}
95
96static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
97 u8 *icv)
98{
99 struct ahash_request *req;
100
101 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
102 crypto_tfm_ctx_alignment());
103
104 ahash_request_set_tfm(req, ahash);
105
106 return req;
107}
108
109static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
110 struct ahash_request *req)
111{
112 return (void *)ALIGN((unsigned long)(req + 1) +
113 crypto_ahash_reqsize(ahash),
114 __alignof__(struct scatterlist));
115}
116
117static bool zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
118{
119 u8 *opt = (u8 *)opthdr;
120 int len = ipv6_optlen(opthdr);
121 int off = 0;
122 int optlen = 0;
123
124 off += 2;
125 len -= 2;
126
127 while (len > 0) {
128
129 switch (opt[off]) {
130
131 case IPV6_TLV_PAD1:
132 optlen = 1;
133 break;
134 default:
135 if (len < 2)
136 goto bad;
137 optlen = opt[off+1]+2;
138 if (len < optlen)
139 goto bad;
140 if (opt[off] & 0x20)
141 memset(&opt[off+2], 0, opt[off+1]);
142 break;
143 }
144
145 off += optlen;
146 len -= optlen;
147 }
148 if (len == 0)
149 return true;
150
151bad:
152 return false;
153}
154
155#if IS_ENABLED(CONFIG_IPV6_MIP6)
156/**
157 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
158 * @iph: IPv6 header
159 * @destopt: destionation options header
160 */
161static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
162{
163 u8 *opt = (u8 *)destopt;
164 int len = ipv6_optlen(destopt);
165 int off = 0;
166 int optlen = 0;
167
168 off += 2;
169 len -= 2;
170
171 while (len > 0) {
172
173 switch (opt[off]) {
174
175 case IPV6_TLV_PAD1:
176 optlen = 1;
177 break;
178 default:
179 if (len < 2)
180 goto bad;
181 optlen = opt[off+1]+2;
182 if (len < optlen)
183 goto bad;
184
185 /* Rearrange the source address in @iph and the
186 * addresses in home address option for final source.
187 * See 11.3.2 of RFC 3775 for details.
188 */
189 if (opt[off] == IPV6_TLV_HAO) {
190 struct in6_addr final_addr;
191 struct ipv6_destopt_hao *hao;
192
193 hao = (struct ipv6_destopt_hao *)&opt[off];
194 if (hao->length != sizeof(hao->addr)) {
195 net_warn_ratelimited("destopt hao: invalid header length: %u\n",
196 hao->length);
197 goto bad;
198 }
199 final_addr = hao->addr;
200 hao->addr = iph->saddr;
201 iph->saddr = final_addr;
202 }
203 break;
204 }
205
206 off += optlen;
207 len -= optlen;
208 }
209 /* Note: ok if len == 0 */
210bad:
211 return;
212}
213#else
214static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
215#endif
216
217/**
218 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
219 * @iph: IPv6 header
220 * @rthdr: routing header
221 *
222 * Rearrange the destination address in @iph and the addresses in @rthdr
223 * so that they appear in the order they will at the final destination.
224 * See Appendix A2 of RFC 2402 for details.
225 */
226static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
227{
228 int segments, segments_left;
229 struct in6_addr *addrs;
230 struct in6_addr final_addr;
231
232 segments_left = rthdr->segments_left;
233 if (segments_left == 0)
234 return;
235 rthdr->segments_left = 0;
236
237 /* The value of rthdr->hdrlen has been verified either by the system
238 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
239 * packets. So we can assume that it is even and that segments is
240 * greater than or equal to segments_left.
241 *
242 * For the same reason we can assume that this option is of type 0.
243 */
244 segments = rthdr->hdrlen >> 1;
245
246 addrs = ((struct rt0_hdr *)rthdr)->addr;
247 final_addr = addrs[segments - 1];
248
249 addrs += segments - segments_left;
250 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
251
252 addrs[0] = iph->daddr;
253 iph->daddr = final_addr;
254}
255
256static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
257{
258 union {
259 struct ipv6hdr *iph;
260 struct ipv6_opt_hdr *opth;
261 struct ipv6_rt_hdr *rth;
262 char *raw;
263 } exthdr = { .iph = iph };
264 char *end = exthdr.raw + len;
265 int nexthdr = iph->nexthdr;
266
267 exthdr.iph++;
268
269 while (exthdr.raw < end) {
270 switch (nexthdr) {
271 case NEXTHDR_DEST:
272 if (dir == XFRM_POLICY_OUT)
273 ipv6_rearrange_destopt(iph, exthdr.opth);
274 /* fall through */
275 case NEXTHDR_HOP:
276 if (!zero_out_mutable_opts(exthdr.opth)) {
277 net_dbg_ratelimited("overrun %sopts\n",
278 nexthdr == NEXTHDR_HOP ?
279 "hop" : "dest");
280 return -EINVAL;
281 }
282 break;
283
284 case NEXTHDR_ROUTING:
285 ipv6_rearrange_rthdr(iph, exthdr.rth);
286 break;
287
288 default:
289 return 0;
290 }
291
292 nexthdr = exthdr.opth->nexthdr;
293 exthdr.raw += ipv6_optlen(exthdr.opth);
294 }
295
296 return 0;
297}
298
299static void ah6_output_done(struct crypto_async_request *base, int err)
300{
301 int extlen;
302 u8 *iph_base;
303 u8 *icv;
304 struct sk_buff *skb = base->data;
305 struct xfrm_state *x = skb_dst(skb)->xfrm;
306 struct ah_data *ahp = x->data;
307 struct ipv6hdr *top_iph = ipv6_hdr(skb);
308 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
309 struct tmp_ext *iph_ext;
310
311 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
312 if (extlen)
313 extlen += sizeof(*iph_ext);
314
315 iph_base = AH_SKB_CB(skb)->tmp;
316 iph_ext = ah_tmp_ext(iph_base);
317 icv = ah_tmp_icv(ahp->ahash, iph_ext, extlen);
318
319 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
320 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
321
322 if (extlen) {
323#if IS_ENABLED(CONFIG_IPV6_MIP6)
324 memcpy(&top_iph->saddr, iph_ext, extlen);
325#else
326 memcpy(&top_iph->daddr, iph_ext, extlen);
327#endif
328 }
329
330 kfree(AH_SKB_CB(skb)->tmp);
331 xfrm_output_resume(skb, err);
332}
333
334static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
335{
336 int err;
337 int nfrags;
338 int extlen;
339 u8 *iph_base;
340 u8 *icv;
341 u8 nexthdr;
342 struct sk_buff *trailer;
343 struct crypto_ahash *ahash;
344 struct ahash_request *req;
345 struct scatterlist *sg;
346 struct ipv6hdr *top_iph;
347 struct ip_auth_hdr *ah;
348 struct ah_data *ahp;
349 struct tmp_ext *iph_ext;
350 int seqhi_len = 0;
351 __be32 *seqhi;
352 int sglists = 0;
353 struct scatterlist *seqhisg;
354
355 ahp = x->data;
356 ahash = ahp->ahash;
357
358 err = skb_cow_data(skb, 0, &trailer);
359 if (err < 0)
360 goto out;
361 nfrags = err;
362
363 skb_push(skb, -skb_network_offset(skb));
364 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
365 if (extlen)
366 extlen += sizeof(*iph_ext);
367
368 if (x->props.flags & XFRM_STATE_ESN) {
369 sglists = 1;
370 seqhi_len = sizeof(*seqhi);
371 }
372 err = -ENOMEM;
373 iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN +
374 extlen + seqhi_len);
375 if (!iph_base)
376 goto out;
377
378 iph_ext = ah_tmp_ext(iph_base);
379 seqhi = (__be32 *)((char *)iph_ext + extlen);
380 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
381 req = ah_tmp_req(ahash, icv);
382 sg = ah_req_sg(ahash, req);
383 seqhisg = sg + nfrags;
384
385 ah = ip_auth_hdr(skb);
386 memset(ah->auth_data, 0, ahp->icv_trunc_len);
387
388 top_iph = ipv6_hdr(skb);
389 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
390
391 nexthdr = *skb_mac_header(skb);
392 *skb_mac_header(skb) = IPPROTO_AH;
393
394 /* When there are no extension headers, we only need to save the first
395 * 8 bytes of the base IP header.
396 */
397 memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
398
399 if (extlen) {
400#if IS_ENABLED(CONFIG_IPV6_MIP6)
401 memcpy(iph_ext, &top_iph->saddr, extlen);
402#else
403 memcpy(iph_ext, &top_iph->daddr, extlen);
404#endif
405 err = ipv6_clear_mutable_options(top_iph,
406 extlen - sizeof(*iph_ext) +
407 sizeof(*top_iph),
408 XFRM_POLICY_OUT);
409 if (err)
410 goto out_free;
411 }
412
413 ah->nexthdr = nexthdr;
414
415 top_iph->priority = 0;
416 top_iph->flow_lbl[0] = 0;
417 top_iph->flow_lbl[1] = 0;
418 top_iph->flow_lbl[2] = 0;
419 top_iph->hop_limit = 0;
420
421 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
422
423 ah->reserved = 0;
424 ah->spi = x->id.spi;
425 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
426
427 sg_init_table(sg, nfrags + sglists);
428 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
429 if (unlikely(err < 0))
430 goto out_free;
431
432 if (x->props.flags & XFRM_STATE_ESN) {
433 /* Attach seqhi sg right after packet payload */
434 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
435 sg_set_buf(seqhisg, seqhi, seqhi_len);
436 }
437 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
438 ahash_request_set_callback(req, 0, ah6_output_done, skb);
439
440 AH_SKB_CB(skb)->tmp = iph_base;
441
442 err = crypto_ahash_digest(req);
443 if (err) {
444 if (err == -EINPROGRESS)
445 goto out;
446
447 if (err == -ENOSPC)
448 err = NET_XMIT_DROP;
449 goto out_free;
450 }
451
452 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
453 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
454
455 if (extlen) {
456#if IS_ENABLED(CONFIG_IPV6_MIP6)
457 memcpy(&top_iph->saddr, iph_ext, extlen);
458#else
459 memcpy(&top_iph->daddr, iph_ext, extlen);
460#endif
461 }
462
463out_free:
464 kfree(iph_base);
465out:
466 return err;
467}
468
469static void ah6_input_done(struct crypto_async_request *base, int err)
470{
471 u8 *auth_data;
472 u8 *icv;
473 u8 *work_iph;
474 struct sk_buff *skb = base->data;
475 struct xfrm_state *x = xfrm_input_state(skb);
476 struct ah_data *ahp = x->data;
477 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
478 int hdr_len = skb_network_header_len(skb);
479 int ah_hlen = (ah->hdrlen + 2) << 2;
480
481 if (err)
482 goto out;
483
484 work_iph = AH_SKB_CB(skb)->tmp;
485 auth_data = ah_tmp_auth(work_iph, hdr_len);
486 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
487
488 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
489 if (err)
490 goto out;
491
492 err = ah->nexthdr;
493
494 skb->network_header += ah_hlen;
495 memcpy(skb_network_header(skb), work_iph, hdr_len);
496 __skb_pull(skb, ah_hlen + hdr_len);
497 if (x->props.mode == XFRM_MODE_TUNNEL)
498 skb_reset_transport_header(skb);
499 else
500 skb_set_transport_header(skb, -hdr_len);
501out:
502 kfree(AH_SKB_CB(skb)->tmp);
503 xfrm_input_resume(skb, err);
504}
505
506
507
508static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
509{
510 /*
511 * Before process AH
512 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
513 * |<-------------->| hdr_len
514 *
515 * To erase AH:
516 * Keeping copy of cleared headers. After AH processing,
517 * Moving the pointer of skb->network_header by using skb_pull as long
518 * as AH header length. Then copy back the copy as long as hdr_len
519 * If destination header following AH exists, copy it into after [Ext2].
520 *
521 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
522 * There is offset of AH before IPv6 header after the process.
523 */
524
525 u8 *auth_data;
526 u8 *icv;
527 u8 *work_iph;
528 struct sk_buff *trailer;
529 struct crypto_ahash *ahash;
530 struct ahash_request *req;
531 struct scatterlist *sg;
532 struct ip_auth_hdr *ah;
533 struct ipv6hdr *ip6h;
534 struct ah_data *ahp;
535 u16 hdr_len;
536 u16 ah_hlen;
537 int nexthdr;
538 int nfrags;
539 int err = -ENOMEM;
540 int seqhi_len = 0;
541 __be32 *seqhi;
542 int sglists = 0;
543 struct scatterlist *seqhisg;
544
545 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
546 goto out;
547
548 /* We are going to _remove_ AH header to keep sockets happy,
549 * so... Later this can change. */
550 if (skb_unclone(skb, GFP_ATOMIC))
551 goto out;
552
553 skb->ip_summed = CHECKSUM_NONE;
554
555 hdr_len = skb_network_header_len(skb);
556 ah = (struct ip_auth_hdr *)skb->data;
557 ahp = x->data;
558 ahash = ahp->ahash;
559
560 nexthdr = ah->nexthdr;
561 ah_hlen = (ah->hdrlen + 2) << 2;
562
563 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
564 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
565 goto out;
566
567 if (!pskb_may_pull(skb, ah_hlen))
568 goto out;
569
570 err = skb_cow_data(skb, 0, &trailer);
571 if (err < 0)
572 goto out;
573 nfrags = err;
574
575 ah = (struct ip_auth_hdr *)skb->data;
576 ip6h = ipv6_hdr(skb);
577
578 skb_push(skb, hdr_len);
579
580 if (x->props.flags & XFRM_STATE_ESN) {
581 sglists = 1;
582 seqhi_len = sizeof(*seqhi);
583 }
584
585 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len +
586 ahp->icv_trunc_len + seqhi_len);
587 if (!work_iph) {
588 err = -ENOMEM;
589 goto out;
590 }
591
592 auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len);
593 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len);
594 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
595 req = ah_tmp_req(ahash, icv);
596 sg = ah_req_sg(ahash, req);
597 seqhisg = sg + nfrags;
598
599 memcpy(work_iph, ip6h, hdr_len);
600 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
601 memset(ah->auth_data, 0, ahp->icv_trunc_len);
602
603 if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
604 goto out_free;
605
606 ip6h->priority = 0;
607 ip6h->flow_lbl[0] = 0;
608 ip6h->flow_lbl[1] = 0;
609 ip6h->flow_lbl[2] = 0;
610 ip6h->hop_limit = 0;
611
612 sg_init_table(sg, nfrags + sglists);
613 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
614 if (unlikely(err < 0))
615 goto out_free;
616
617 if (x->props.flags & XFRM_STATE_ESN) {
618 /* Attach seqhi sg right after packet payload */
619 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
620 sg_set_buf(seqhisg, seqhi, seqhi_len);
621 }
622
623 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
624 ahash_request_set_callback(req, 0, ah6_input_done, skb);
625
626 AH_SKB_CB(skb)->tmp = work_iph;
627
628 err = crypto_ahash_digest(req);
629 if (err) {
630 if (err == -EINPROGRESS)
631 goto out;
632
633 goto out_free;
634 }
635
636 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
637 if (err)
638 goto out_free;
639
640 skb->network_header += ah_hlen;
641 memcpy(skb_network_header(skb), work_iph, hdr_len);
642 __skb_pull(skb, ah_hlen + hdr_len);
643
644 if (x->props.mode == XFRM_MODE_TUNNEL)
645 skb_reset_transport_header(skb);
646 else
647 skb_set_transport_header(skb, -hdr_len);
648
649 err = nexthdr;
650
651out_free:
652 kfree(work_iph);
653out:
654 return err;
655}
656
657static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
658 u8 type, u8 code, int offset, __be32 info)
659{
660 struct net *net = dev_net(skb->dev);
661 struct ipv6hdr *iph = (struct ipv6hdr *)skb->data;
662 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+offset);
663 struct xfrm_state *x;
664
665 if (type != ICMPV6_PKT_TOOBIG &&
666 type != NDISC_REDIRECT)
667 return 0;
668
669 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
670 if (!x)
671 return 0;
672
673 if (type == NDISC_REDIRECT)
674 ip6_redirect(skb, net, skb->dev->ifindex, 0,
675 sock_net_uid(net, NULL));
676 else
677 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
678 xfrm_state_put(x);
679
680 return 0;
681}
682
683static int ah6_init_state(struct xfrm_state *x)
684{
685 struct ah_data *ahp = NULL;
686 struct xfrm_algo_desc *aalg_desc;
687 struct crypto_ahash *ahash;
688
689 if (!x->aalg)
690 goto error;
691
692 if (x->encap)
693 goto error;
694
695 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
696 if (!ahp)
697 return -ENOMEM;
698
699 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
700 if (IS_ERR(ahash))
701 goto error;
702
703 ahp->ahash = ahash;
704 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
705 (x->aalg->alg_key_len + 7) / 8))
706 goto error;
707
708 /*
709 * Lookup the algorithm description maintained by xfrm_algo,
710 * verify crypto transform properties, and store information
711 * we need for AH processing. This lookup cannot fail here
712 * after a successful crypto_alloc_hash().
713 */
714 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
715 BUG_ON(!aalg_desc);
716
717 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
718 crypto_ahash_digestsize(ahash)) {
719 pr_info("AH: %s digestsize %u != %hu\n",
720 x->aalg->alg_name, crypto_ahash_digestsize(ahash),
721 aalg_desc->uinfo.auth.icv_fullbits/8);
722 goto error;
723 }
724
725 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
726 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
727
728 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
729 ahp->icv_trunc_len);
730 switch (x->props.mode) {
731 case XFRM_MODE_BEET:
732 case XFRM_MODE_TRANSPORT:
733 break;
734 case XFRM_MODE_TUNNEL:
735 x->props.header_len += sizeof(struct ipv6hdr);
736 break;
737 default:
738 goto error;
739 }
740 x->data = ahp;
741
742 return 0;
743
744error:
745 if (ahp) {
746 crypto_free_ahash(ahp->ahash);
747 kfree(ahp);
748 }
749 return -EINVAL;
750}
751
752static void ah6_destroy(struct xfrm_state *x)
753{
754 struct ah_data *ahp = x->data;
755
756 if (!ahp)
757 return;
758
759 crypto_free_ahash(ahp->ahash);
760 kfree(ahp);
761}
762
763static int ah6_rcv_cb(struct sk_buff *skb, int err)
764{
765 return 0;
766}
767
768static const struct xfrm_type ah6_type = {
769 .description = "AH6",
770 .owner = THIS_MODULE,
771 .proto = IPPROTO_AH,
772 .flags = XFRM_TYPE_REPLAY_PROT,
773 .init_state = ah6_init_state,
774 .destructor = ah6_destroy,
775 .input = ah6_input,
776 .output = ah6_output,
777 .hdr_offset = xfrm6_find_1stfragopt,
778};
779
780static struct xfrm6_protocol ah6_protocol = {
781 .handler = xfrm6_rcv,
782 .cb_handler = ah6_rcv_cb,
783 .err_handler = ah6_err,
784 .priority = 0,
785};
786
787static int __init ah6_init(void)
788{
789 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
790 pr_info("%s: can't add xfrm type\n", __func__);
791 return -EAGAIN;
792 }
793
794 if (xfrm6_protocol_register(&ah6_protocol, IPPROTO_AH) < 0) {
795 pr_info("%s: can't add protocol\n", __func__);
796 xfrm_unregister_type(&ah6_type, AF_INET6);
797 return -EAGAIN;
798 }
799
800 return 0;
801}
802
803static void __exit ah6_fini(void)
804{
805 if (xfrm6_protocol_deregister(&ah6_protocol, IPPROTO_AH) < 0)
806 pr_info("%s: can't remove protocol\n", __func__);
807
808 if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
809 pr_info("%s: can't remove xfrm type\n", __func__);
810
811}
812
813module_init(ah6_init);
814module_exit(ah6_fini);
815
816MODULE_LICENSE("GPL");
817MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);