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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, 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/hash.h>
29#include <linux/module.h>
30#include <linux/slab.h>
31#include <net/ip.h>
32#include <net/ah.h>
33#include <linux/crypto.h>
34#include <linux/pfkeyv2.h>
35#include <linux/string.h>
36#include <linux/scatterlist.h>
37#include <net/ip6_route.h>
38#include <net/icmp.h>
39#include <net/ipv6.h>
40#include <net/protocol.h>
41#include <net/xfrm.h>
42
43#define IPV6HDR_BASELEN 8
44
45struct tmp_ext {
46#if IS_ENABLED(CONFIG_IPV6_MIP6)
47 struct in6_addr saddr;
48#endif
49 struct in6_addr daddr;
50 char hdrs[0];
51};
52
53struct ah_skb_cb {
54 struct xfrm_skb_cb xfrm;
55 void *tmp;
56};
57
58#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
59
60static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
61 unsigned int size)
62{
63 unsigned int len;
64
65 len = size + crypto_ahash_digestsize(ahash) +
66 (crypto_ahash_alignmask(ahash) &
67 ~(crypto_tfm_ctx_alignment() - 1));
68
69 len = ALIGN(len, crypto_tfm_ctx_alignment());
70
71 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
72 len = ALIGN(len, __alignof__(struct scatterlist));
73
74 len += sizeof(struct scatterlist) * nfrags;
75
76 return kmalloc(len, GFP_ATOMIC);
77}
78
79static inline struct tmp_ext *ah_tmp_ext(void *base)
80{
81 return base + IPV6HDR_BASELEN;
82}
83
84static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
85{
86 return tmp + offset;
87}
88
89static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
90 unsigned int offset)
91{
92 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
93}
94
95static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
96 u8 *icv)
97{
98 struct ahash_request *req;
99
100 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
101 crypto_tfm_ctx_alignment());
102
103 ahash_request_set_tfm(req, ahash);
104
105 return req;
106}
107
108static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
109 struct ahash_request *req)
110{
111 return (void *)ALIGN((unsigned long)(req + 1) +
112 crypto_ahash_reqsize(ahash),
113 __alignof__(struct scatterlist));
114}
115
116static bool zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
117{
118 u8 *opt = (u8 *)opthdr;
119 int len = ipv6_optlen(opthdr);
120 int off = 0;
121 int optlen = 0;
122
123 off += 2;
124 len -= 2;
125
126 while (len > 0) {
127
128 switch (opt[off]) {
129
130 case IPV6_TLV_PAD1:
131 optlen = 1;
132 break;
133 default:
134 if (len < 2)
135 goto bad;
136 optlen = opt[off+1]+2;
137 if (len < optlen)
138 goto bad;
139 if (opt[off] & 0x20)
140 memset(&opt[off+2], 0, opt[off+1]);
141 break;
142 }
143
144 off += optlen;
145 len -= optlen;
146 }
147 if (len == 0)
148 return true;
149
150bad:
151 return false;
152}
153
154#if IS_ENABLED(CONFIG_IPV6_MIP6)
155/**
156 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
157 * @iph: IPv6 header
158 * @destopt: destionation options header
159 */
160static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
161{
162 u8 *opt = (u8 *)destopt;
163 int len = ipv6_optlen(destopt);
164 int off = 0;
165 int optlen = 0;
166
167 off += 2;
168 len -= 2;
169
170 while (len > 0) {
171
172 switch (opt[off]) {
173
174 case IPV6_TLV_PAD1:
175 optlen = 1;
176 break;
177 default:
178 if (len < 2)
179 goto bad;
180 optlen = opt[off+1]+2;
181 if (len < optlen)
182 goto bad;
183
184 /* Rearrange the source address in @iph and the
185 * addresses in home address option for final source.
186 * See 11.3.2 of RFC 3775 for details.
187 */
188 if (opt[off] == IPV6_TLV_HAO) {
189 struct in6_addr final_addr;
190 struct ipv6_destopt_hao *hao;
191
192 hao = (struct ipv6_destopt_hao *)&opt[off];
193 if (hao->length != sizeof(hao->addr)) {
194 net_warn_ratelimited("destopt hao: invalid header length: %u\n",
195 hao->length);
196 goto bad;
197 }
198 final_addr = hao->addr;
199 hao->addr = iph->saddr;
200 iph->saddr = final_addr;
201 }
202 break;
203 }
204
205 off += optlen;
206 len -= optlen;
207 }
208 /* Note: ok if len == 0 */
209bad:
210 return;
211}
212#else
213static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
214#endif
215
216/**
217 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
218 * @iph: IPv6 header
219 * @rthdr: routing header
220 *
221 * Rearrange the destination address in @iph and the addresses in @rthdr
222 * so that they appear in the order they will at the final destination.
223 * See Appendix A2 of RFC 2402 for details.
224 */
225static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
226{
227 int segments, segments_left;
228 struct in6_addr *addrs;
229 struct in6_addr final_addr;
230
231 segments_left = rthdr->segments_left;
232 if (segments_left == 0)
233 return;
234 rthdr->segments_left = 0;
235
236 /* The value of rthdr->hdrlen has been verified either by the system
237 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
238 * packets. So we can assume that it is even and that segments is
239 * greater than or equal to segments_left.
240 *
241 * For the same reason we can assume that this option is of type 0.
242 */
243 segments = rthdr->hdrlen >> 1;
244
245 addrs = ((struct rt0_hdr *)rthdr)->addr;
246 final_addr = addrs[segments - 1];
247
248 addrs += segments - segments_left;
249 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
250
251 addrs[0] = iph->daddr;
252 iph->daddr = final_addr;
253}
254
255static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
256{
257 union {
258 struct ipv6hdr *iph;
259 struct ipv6_opt_hdr *opth;
260 struct ipv6_rt_hdr *rth;
261 char *raw;
262 } exthdr = { .iph = iph };
263 char *end = exthdr.raw + len;
264 int nexthdr = iph->nexthdr;
265
266 exthdr.iph++;
267
268 while (exthdr.raw < end) {
269 switch (nexthdr) {
270 case NEXTHDR_DEST:
271 if (dir == XFRM_POLICY_OUT)
272 ipv6_rearrange_destopt(iph, exthdr.opth);
273 case NEXTHDR_HOP:
274 if (!zero_out_mutable_opts(exthdr.opth)) {
275 LIMIT_NETDEBUG(
276 KERN_WARNING "overrun %sopts\n",
277 nexthdr == NEXTHDR_HOP ?
278 "hop" : "dest");
279 return -EINVAL;
280 }
281 break;
282
283 case NEXTHDR_ROUTING:
284 ipv6_rearrange_rthdr(iph, exthdr.rth);
285 break;
286
287 default :
288 return 0;
289 }
290
291 nexthdr = exthdr.opth->nexthdr;
292 exthdr.raw += ipv6_optlen(exthdr.opth);
293 }
294
295 return 0;
296}
297
298static void ah6_output_done(struct crypto_async_request *base, int err)
299{
300 int extlen;
301 u8 *iph_base;
302 u8 *icv;
303 struct sk_buff *skb = base->data;
304 struct xfrm_state *x = skb_dst(skb)->xfrm;
305 struct ah_data *ahp = x->data;
306 struct ipv6hdr *top_iph = ipv6_hdr(skb);
307 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
308 struct tmp_ext *iph_ext;
309
310 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
311 if (extlen)
312 extlen += sizeof(*iph_ext);
313
314 iph_base = AH_SKB_CB(skb)->tmp;
315 iph_ext = ah_tmp_ext(iph_base);
316 icv = ah_tmp_icv(ahp->ahash, iph_ext, extlen);
317
318 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
319 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
320
321 if (extlen) {
322#if IS_ENABLED(CONFIG_IPV6_MIP6)
323 memcpy(&top_iph->saddr, iph_ext, extlen);
324#else
325 memcpy(&top_iph->daddr, iph_ext, extlen);
326#endif
327 }
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 int seqhi_len = 0;
350 __be32 *seqhi;
351 int sglists = 0;
352 struct scatterlist *seqhisg;
353
354 ahp = x->data;
355 ahash = ahp->ahash;
356
357 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
358 goto out;
359 nfrags = err;
360
361 skb_push(skb, -skb_network_offset(skb));
362 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
363 if (extlen)
364 extlen += sizeof(*iph_ext);
365
366 if (x->props.flags & XFRM_STATE_ESN) {
367 sglists = 1;
368 seqhi_len = sizeof(*seqhi);
369 }
370 err = -ENOMEM;
371 iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN +
372 extlen + seqhi_len);
373 if (!iph_base)
374 goto out;
375
376 iph_ext = ah_tmp_ext(iph_base);
377 seqhi = (__be32 *)((char *)iph_ext + extlen);
378 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
379 req = ah_tmp_req(ahash, icv);
380 sg = ah_req_sg(ahash, req);
381 seqhisg = sg + nfrags;
382
383 ah = ip_auth_hdr(skb);
384 memset(ah->auth_data, 0, ahp->icv_trunc_len);
385
386 top_iph = ipv6_hdr(skb);
387 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
388
389 nexthdr = *skb_mac_header(skb);
390 *skb_mac_header(skb) = IPPROTO_AH;
391
392 /* When there are no extension headers, we only need to save the first
393 * 8 bytes of the base IP header.
394 */
395 memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
396
397 if (extlen) {
398#if IS_ENABLED(CONFIG_IPV6_MIP6)
399 memcpy(iph_ext, &top_iph->saddr, extlen);
400#else
401 memcpy(iph_ext, &top_iph->daddr, extlen);
402#endif
403 err = ipv6_clear_mutable_options(top_iph,
404 extlen - sizeof(*iph_ext) +
405 sizeof(*top_iph),
406 XFRM_POLICY_OUT);
407 if (err)
408 goto out_free;
409 }
410
411 ah->nexthdr = nexthdr;
412
413 top_iph->priority = 0;
414 top_iph->flow_lbl[0] = 0;
415 top_iph->flow_lbl[1] = 0;
416 top_iph->flow_lbl[2] = 0;
417 top_iph->hop_limit = 0;
418
419 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
420
421 ah->reserved = 0;
422 ah->spi = x->id.spi;
423 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
424
425 sg_init_table(sg, nfrags + sglists);
426 skb_to_sgvec_nomark(skb, sg, 0, skb->len);
427
428 if (x->props.flags & XFRM_STATE_ESN) {
429 /* Attach seqhi sg right after packet payload */
430 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
431 sg_set_buf(seqhisg, seqhi, seqhi_len);
432 }
433 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
434 ahash_request_set_callback(req, 0, ah6_output_done, skb);
435
436 AH_SKB_CB(skb)->tmp = iph_base;
437
438 err = crypto_ahash_digest(req);
439 if (err) {
440 if (err == -EINPROGRESS)
441 goto out;
442
443 if (err == -EBUSY)
444 err = NET_XMIT_DROP;
445 goto out_free;
446 }
447
448 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
449 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
450
451 if (extlen) {
452#if IS_ENABLED(CONFIG_IPV6_MIP6)
453 memcpy(&top_iph->saddr, iph_ext, extlen);
454#else
455 memcpy(&top_iph->daddr, iph_ext, extlen);
456#endif
457 }
458
459out_free:
460 kfree(iph_base);
461out:
462 return err;
463}
464
465static void ah6_input_done(struct crypto_async_request *base, int err)
466{
467 u8 *auth_data;
468 u8 *icv;
469 u8 *work_iph;
470 struct sk_buff *skb = base->data;
471 struct xfrm_state *x = xfrm_input_state(skb);
472 struct ah_data *ahp = x->data;
473 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
474 int hdr_len = skb_network_header_len(skb);
475 int ah_hlen = (ah->hdrlen + 2) << 2;
476
477 work_iph = AH_SKB_CB(skb)->tmp;
478 auth_data = ah_tmp_auth(work_iph, hdr_len);
479 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
480
481 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
482 if (err)
483 goto out;
484
485 err = ah->nexthdr;
486
487 skb->network_header += ah_hlen;
488 memcpy(skb_network_header(skb), work_iph, hdr_len);
489 __skb_pull(skb, ah_hlen + hdr_len);
490 if (x->props.mode == XFRM_MODE_TUNNEL)
491 skb_reset_transport_header(skb);
492 else
493 skb_set_transport_header(skb, -hdr_len);
494out:
495 kfree(AH_SKB_CB(skb)->tmp);
496 xfrm_input_resume(skb, err);
497}
498
499
500
501static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
502{
503 /*
504 * Before process AH
505 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
506 * |<-------------->| hdr_len
507 *
508 * To erase AH:
509 * Keeping copy of cleared headers. After AH processing,
510 * Moving the pointer of skb->network_header by using skb_pull as long
511 * as AH header length. Then copy back the copy as long as hdr_len
512 * If destination header following AH exists, copy it into after [Ext2].
513 *
514 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
515 * There is offset of AH before IPv6 header after the process.
516 */
517
518 u8 *auth_data;
519 u8 *icv;
520 u8 *work_iph;
521 struct sk_buff *trailer;
522 struct crypto_ahash *ahash;
523 struct ahash_request *req;
524 struct scatterlist *sg;
525 struct ip_auth_hdr *ah;
526 struct ipv6hdr *ip6h;
527 struct ah_data *ahp;
528 u16 hdr_len;
529 u16 ah_hlen;
530 int nexthdr;
531 int nfrags;
532 int err = -ENOMEM;
533 int seqhi_len = 0;
534 __be32 *seqhi;
535 int sglists = 0;
536 struct scatterlist *seqhisg;
537
538 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
539 goto out;
540
541 /* We are going to _remove_ AH header to keep sockets happy,
542 * so... Later this can change. */
543 if (skb_unclone(skb, GFP_ATOMIC))
544 goto out;
545
546 skb->ip_summed = CHECKSUM_NONE;
547
548 hdr_len = skb_network_header_len(skb);
549 ah = (struct ip_auth_hdr *)skb->data;
550 ahp = x->data;
551 ahash = ahp->ahash;
552
553 nexthdr = ah->nexthdr;
554 ah_hlen = (ah->hdrlen + 2) << 2;
555
556 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
557 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
558 goto out;
559
560 if (!pskb_may_pull(skb, ah_hlen))
561 goto out;
562
563
564 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
565 goto out;
566 nfrags = err;
567
568 ah = (struct ip_auth_hdr *)skb->data;
569 ip6h = ipv6_hdr(skb);
570
571 skb_push(skb, hdr_len);
572
573 if (x->props.flags & XFRM_STATE_ESN) {
574 sglists = 1;
575 seqhi_len = sizeof(*seqhi);
576 }
577
578 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len +
579 ahp->icv_trunc_len + seqhi_len);
580 if (!work_iph)
581 goto out;
582
583 auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len);
584 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len);
585 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
586 req = ah_tmp_req(ahash, icv);
587 sg = ah_req_sg(ahash, req);
588 seqhisg = sg + nfrags;
589
590 memcpy(work_iph, ip6h, hdr_len);
591 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
592 memset(ah->auth_data, 0, ahp->icv_trunc_len);
593
594 if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
595 goto out_free;
596
597 ip6h->priority = 0;
598 ip6h->flow_lbl[0] = 0;
599 ip6h->flow_lbl[1] = 0;
600 ip6h->flow_lbl[2] = 0;
601 ip6h->hop_limit = 0;
602
603 sg_init_table(sg, nfrags + sglists);
604 skb_to_sgvec_nomark(skb, sg, 0, skb->len);
605
606 if (x->props.flags & XFRM_STATE_ESN) {
607 /* Attach seqhi sg right after packet payload */
608 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
609 sg_set_buf(seqhisg, seqhi, seqhi_len);
610 }
611
612 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
613 ahash_request_set_callback(req, 0, ah6_input_done, skb);
614
615 AH_SKB_CB(skb)->tmp = work_iph;
616
617 err = crypto_ahash_digest(req);
618 if (err) {
619 if (err == -EINPROGRESS)
620 goto out;
621
622 goto out_free;
623 }
624
625 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
626 if (err)
627 goto out_free;
628
629 skb->network_header += ah_hlen;
630 memcpy(skb_network_header(skb), work_iph, hdr_len);
631 __skb_pull(skb, ah_hlen + hdr_len);
632
633 if (x->props.mode == XFRM_MODE_TUNNEL)
634 skb_reset_transport_header(skb);
635 else
636 skb_set_transport_header(skb, -hdr_len);
637
638 err = nexthdr;
639
640out_free:
641 kfree(work_iph);
642out:
643 return err;
644}
645
646static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
647 u8 type, u8 code, int offset, __be32 info)
648{
649 struct net *net = dev_net(skb->dev);
650 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
651 struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+offset);
652 struct xfrm_state *x;
653
654 if (type != ICMPV6_PKT_TOOBIG &&
655 type != NDISC_REDIRECT)
656 return 0;
657
658 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
659 if (!x)
660 return 0;
661
662 if (type == NDISC_REDIRECT)
663 ip6_redirect(skb, net, skb->dev->ifindex, 0);
664 else
665 ip6_update_pmtu(skb, net, info, 0, 0);
666 xfrm_state_put(x);
667
668 return 0;
669}
670
671static int ah6_init_state(struct xfrm_state *x)
672{
673 struct ah_data *ahp = NULL;
674 struct xfrm_algo_desc *aalg_desc;
675 struct crypto_ahash *ahash;
676
677 if (!x->aalg)
678 goto error;
679
680 if (x->encap)
681 goto error;
682
683 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
684 if (ahp == NULL)
685 return -ENOMEM;
686
687 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
688 if (IS_ERR(ahash))
689 goto error;
690
691 ahp->ahash = ahash;
692 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
693 (x->aalg->alg_key_len + 7) / 8))
694 goto error;
695
696 /*
697 * Lookup the algorithm description maintained by xfrm_algo,
698 * verify crypto transform properties, and store information
699 * we need for AH processing. This lookup cannot fail here
700 * after a successful crypto_alloc_hash().
701 */
702 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
703 BUG_ON(!aalg_desc);
704
705 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
706 crypto_ahash_digestsize(ahash)) {
707 pr_info("AH: %s digestsize %u != %hu\n",
708 x->aalg->alg_name, crypto_ahash_digestsize(ahash),
709 aalg_desc->uinfo.auth.icv_fullbits/8);
710 goto error;
711 }
712
713 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
714 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
715
716 BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
717
718 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
719 ahp->icv_trunc_len);
720 switch (x->props.mode) {
721 case XFRM_MODE_BEET:
722 case XFRM_MODE_TRANSPORT:
723 break;
724 case XFRM_MODE_TUNNEL:
725 x->props.header_len += sizeof(struct ipv6hdr);
726 break;
727 default:
728 goto error;
729 }
730 x->data = ahp;
731
732 return 0;
733
734error:
735 if (ahp) {
736 crypto_free_ahash(ahp->ahash);
737 kfree(ahp);
738 }
739 return -EINVAL;
740}
741
742static void ah6_destroy(struct xfrm_state *x)
743{
744 struct ah_data *ahp = x->data;
745
746 if (!ahp)
747 return;
748
749 crypto_free_ahash(ahp->ahash);
750 kfree(ahp);
751}
752
753static int ah6_rcv_cb(struct sk_buff *skb, int err)
754{
755 return 0;
756}
757
758static const struct xfrm_type ah6_type =
759{
760 .description = "AH6",
761 .owner = THIS_MODULE,
762 .proto = IPPROTO_AH,
763 .flags = XFRM_TYPE_REPLAY_PROT,
764 .init_state = ah6_init_state,
765 .destructor = ah6_destroy,
766 .input = ah6_input,
767 .output = ah6_output,
768 .hdr_offset = xfrm6_find_1stfragopt,
769};
770
771static struct xfrm6_protocol ah6_protocol = {
772 .handler = xfrm6_rcv,
773 .cb_handler = ah6_rcv_cb,
774 .err_handler = ah6_err,
775 .priority = 0,
776};
777
778static int __init ah6_init(void)
779{
780 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
781 pr_info("%s: can't add xfrm type\n", __func__);
782 return -EAGAIN;
783 }
784
785 if (xfrm6_protocol_register(&ah6_protocol, IPPROTO_AH) < 0) {
786 pr_info("%s: can't add protocol\n", __func__);
787 xfrm_unregister_type(&ah6_type, AF_INET6);
788 return -EAGAIN;
789 }
790
791 return 0;
792}
793
794static void __exit ah6_fini(void)
795{
796 if (xfrm6_protocol_deregister(&ah6_protocol, IPPROTO_AH) < 0)
797 pr_info("%s: can't remove protocol\n", __func__);
798
799 if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
800 pr_info("%s: can't remove xfrm type\n", __func__);
801
802}
803
804module_init(ah6_init);
805module_exit(ah6_fini);
806
807MODULE_LICENSE("GPL");
808MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C)2002 USAGI/WIDE Project
4 *
5 * Authors
6 *
7 * Mitsuru KANDA @USAGI : IPv6 Support
8 * Kazunori MIYAZAWA @USAGI :
9 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
10 *
11 * This file is derived from net/ipv4/ah.c.
12 */
13
14#define pr_fmt(fmt) "IPv6: " fmt
15
16#include <crypto/algapi.h>
17#include <crypto/hash.h>
18#include <linux/module.h>
19#include <linux/slab.h>
20#include <net/ip.h>
21#include <net/ah.h>
22#include <linux/crypto.h>
23#include <linux/pfkeyv2.h>
24#include <linux/string.h>
25#include <linux/scatterlist.h>
26#include <net/ip6_route.h>
27#include <net/icmp.h>
28#include <net/ipv6.h>
29#include <net/protocol.h>
30#include <net/xfrm.h>
31
32#define IPV6HDR_BASELEN 8
33
34struct tmp_ext {
35#if IS_ENABLED(CONFIG_IPV6_MIP6)
36 struct in6_addr saddr;
37#endif
38 struct in6_addr daddr;
39 char hdrs[];
40};
41
42struct ah_skb_cb {
43 struct xfrm_skb_cb xfrm;
44 void *tmp;
45};
46
47#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
48
49static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
50 unsigned int size)
51{
52 unsigned int len;
53
54 len = size + crypto_ahash_digestsize(ahash) +
55 (crypto_ahash_alignmask(ahash) &
56 ~(crypto_tfm_ctx_alignment() - 1));
57
58 len = ALIGN(len, crypto_tfm_ctx_alignment());
59
60 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
61 len = ALIGN(len, __alignof__(struct scatterlist));
62
63 len += sizeof(struct scatterlist) * nfrags;
64
65 return kmalloc(len, GFP_ATOMIC);
66}
67
68static inline struct tmp_ext *ah_tmp_ext(void *base)
69{
70 return base + IPV6HDR_BASELEN;
71}
72
73static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
74{
75 return tmp + offset;
76}
77
78static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
79 unsigned int offset)
80{
81 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
82}
83
84static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
85 u8 *icv)
86{
87 struct ahash_request *req;
88
89 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
90 crypto_tfm_ctx_alignment());
91
92 ahash_request_set_tfm(req, ahash);
93
94 return req;
95}
96
97static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
98 struct ahash_request *req)
99{
100 return (void *)ALIGN((unsigned long)(req + 1) +
101 crypto_ahash_reqsize(ahash),
102 __alignof__(struct scatterlist));
103}
104
105static bool zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
106{
107 u8 *opt = (u8 *)opthdr;
108 int len = ipv6_optlen(opthdr);
109 int off = 0;
110 int optlen = 0;
111
112 off += 2;
113 len -= 2;
114
115 while (len > 0) {
116
117 switch (opt[off]) {
118
119 case IPV6_TLV_PAD1:
120 optlen = 1;
121 break;
122 default:
123 if (len < 2)
124 goto bad;
125 optlen = opt[off+1]+2;
126 if (len < optlen)
127 goto bad;
128 if (opt[off] & 0x20)
129 memset(&opt[off+2], 0, opt[off+1]);
130 break;
131 }
132
133 off += optlen;
134 len -= optlen;
135 }
136 if (len == 0)
137 return true;
138
139bad:
140 return false;
141}
142
143#if IS_ENABLED(CONFIG_IPV6_MIP6)
144/**
145 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
146 * @iph: IPv6 header
147 * @destopt: destionation options header
148 */
149static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
150{
151 u8 *opt = (u8 *)destopt;
152 int len = ipv6_optlen(destopt);
153 int off = 0;
154 int optlen = 0;
155
156 off += 2;
157 len -= 2;
158
159 while (len > 0) {
160
161 switch (opt[off]) {
162
163 case IPV6_TLV_PAD1:
164 optlen = 1;
165 break;
166 default:
167 if (len < 2)
168 goto bad;
169 optlen = opt[off+1]+2;
170 if (len < optlen)
171 goto bad;
172
173 /* Rearrange the source address in @iph and the
174 * addresses in home address option for final source.
175 * See 11.3.2 of RFC 3775 for details.
176 */
177 if (opt[off] == IPV6_TLV_HAO) {
178 struct in6_addr final_addr;
179 struct ipv6_destopt_hao *hao;
180
181 hao = (struct ipv6_destopt_hao *)&opt[off];
182 if (hao->length != sizeof(hao->addr)) {
183 net_warn_ratelimited("destopt hao: invalid header length: %u\n",
184 hao->length);
185 goto bad;
186 }
187 final_addr = hao->addr;
188 hao->addr = iph->saddr;
189 iph->saddr = final_addr;
190 }
191 break;
192 }
193
194 off += optlen;
195 len -= optlen;
196 }
197 /* Note: ok if len == 0 */
198bad:
199 return;
200}
201#else
202static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
203#endif
204
205/**
206 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
207 * @iph: IPv6 header
208 * @rthdr: routing header
209 *
210 * Rearrange the destination address in @iph and the addresses in @rthdr
211 * so that they appear in the order they will at the final destination.
212 * See Appendix A2 of RFC 2402 for details.
213 */
214static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
215{
216 int segments, segments_left;
217 struct in6_addr *addrs;
218 struct in6_addr final_addr;
219
220 segments_left = rthdr->segments_left;
221 if (segments_left == 0)
222 return;
223 rthdr->segments_left = 0;
224
225 /* The value of rthdr->hdrlen has been verified either by the system
226 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
227 * packets. So we can assume that it is even and that segments is
228 * greater than or equal to segments_left.
229 *
230 * For the same reason we can assume that this option is of type 0.
231 */
232 segments = rthdr->hdrlen >> 1;
233
234 addrs = ((struct rt0_hdr *)rthdr)->addr;
235 final_addr = addrs[segments - 1];
236
237 addrs += segments - segments_left;
238 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
239
240 addrs[0] = iph->daddr;
241 iph->daddr = final_addr;
242}
243
244static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
245{
246 union {
247 struct ipv6hdr *iph;
248 struct ipv6_opt_hdr *opth;
249 struct ipv6_rt_hdr *rth;
250 char *raw;
251 } exthdr = { .iph = iph };
252 char *end = exthdr.raw + len;
253 int nexthdr = iph->nexthdr;
254
255 exthdr.iph++;
256
257 while (exthdr.raw < end) {
258 switch (nexthdr) {
259 case NEXTHDR_DEST:
260 if (dir == XFRM_POLICY_OUT)
261 ipv6_rearrange_destopt(iph, exthdr.opth);
262 fallthrough;
263 case NEXTHDR_HOP:
264 if (!zero_out_mutable_opts(exthdr.opth)) {
265 net_dbg_ratelimited("overrun %sopts\n",
266 nexthdr == NEXTHDR_HOP ?
267 "hop" : "dest");
268 return -EINVAL;
269 }
270 break;
271
272 case NEXTHDR_ROUTING:
273 ipv6_rearrange_rthdr(iph, exthdr.rth);
274 break;
275
276 default:
277 return 0;
278 }
279
280 nexthdr = exthdr.opth->nexthdr;
281 exthdr.raw += ipv6_optlen(exthdr.opth);
282 }
283
284 return 0;
285}
286
287static void ah6_output_done(struct crypto_async_request *base, int err)
288{
289 int extlen;
290 u8 *iph_base;
291 u8 *icv;
292 struct sk_buff *skb = base->data;
293 struct xfrm_state *x = skb_dst(skb)->xfrm;
294 struct ah_data *ahp = x->data;
295 struct ipv6hdr *top_iph = ipv6_hdr(skb);
296 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
297 struct tmp_ext *iph_ext;
298
299 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
300 if (extlen)
301 extlen += sizeof(*iph_ext);
302
303 iph_base = AH_SKB_CB(skb)->tmp;
304 iph_ext = ah_tmp_ext(iph_base);
305 icv = ah_tmp_icv(ahp->ahash, iph_ext, extlen);
306
307 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
308 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
309
310 if (extlen) {
311#if IS_ENABLED(CONFIG_IPV6_MIP6)
312 memcpy(&top_iph->saddr, iph_ext, extlen);
313#else
314 memcpy(&top_iph->daddr, iph_ext, extlen);
315#endif
316 }
317
318 kfree(AH_SKB_CB(skb)->tmp);
319 xfrm_output_resume(skb->sk, skb, err);
320}
321
322static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
323{
324 int err;
325 int nfrags;
326 int extlen;
327 u8 *iph_base;
328 u8 *icv;
329 u8 nexthdr;
330 struct sk_buff *trailer;
331 struct crypto_ahash *ahash;
332 struct ahash_request *req;
333 struct scatterlist *sg;
334 struct ipv6hdr *top_iph;
335 struct ip_auth_hdr *ah;
336 struct ah_data *ahp;
337 struct tmp_ext *iph_ext;
338 int seqhi_len = 0;
339 __be32 *seqhi;
340 int sglists = 0;
341 struct scatterlist *seqhisg;
342
343 ahp = x->data;
344 ahash = ahp->ahash;
345
346 err = skb_cow_data(skb, 0, &trailer);
347 if (err < 0)
348 goto out;
349 nfrags = err;
350
351 skb_push(skb, -skb_network_offset(skb));
352 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
353 if (extlen)
354 extlen += sizeof(*iph_ext);
355
356 if (x->props.flags & XFRM_STATE_ESN) {
357 sglists = 1;
358 seqhi_len = sizeof(*seqhi);
359 }
360 err = -ENOMEM;
361 iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN +
362 extlen + seqhi_len);
363 if (!iph_base)
364 goto out;
365
366 iph_ext = ah_tmp_ext(iph_base);
367 seqhi = (__be32 *)((char *)iph_ext + extlen);
368 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
369 req = ah_tmp_req(ahash, icv);
370 sg = ah_req_sg(ahash, req);
371 seqhisg = sg + nfrags;
372
373 ah = ip_auth_hdr(skb);
374 memset(ah->auth_data, 0, ahp->icv_trunc_len);
375
376 top_iph = ipv6_hdr(skb);
377 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
378
379 nexthdr = *skb_mac_header(skb);
380 *skb_mac_header(skb) = IPPROTO_AH;
381
382 /* When there are no extension headers, we only need to save the first
383 * 8 bytes of the base IP header.
384 */
385 memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
386
387 if (extlen) {
388#if IS_ENABLED(CONFIG_IPV6_MIP6)
389 memcpy(iph_ext, &top_iph->saddr, extlen);
390#else
391 memcpy(iph_ext, &top_iph->daddr, extlen);
392#endif
393 err = ipv6_clear_mutable_options(top_iph,
394 extlen - sizeof(*iph_ext) +
395 sizeof(*top_iph),
396 XFRM_POLICY_OUT);
397 if (err)
398 goto out_free;
399 }
400
401 ah->nexthdr = nexthdr;
402
403 top_iph->priority = 0;
404 top_iph->flow_lbl[0] = 0;
405 top_iph->flow_lbl[1] = 0;
406 top_iph->flow_lbl[2] = 0;
407 top_iph->hop_limit = 0;
408
409 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
410
411 ah->reserved = 0;
412 ah->spi = x->id.spi;
413 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
414
415 sg_init_table(sg, nfrags + sglists);
416 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
417 if (unlikely(err < 0))
418 goto out_free;
419
420 if (x->props.flags & XFRM_STATE_ESN) {
421 /* Attach seqhi sg right after packet payload */
422 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
423 sg_set_buf(seqhisg, seqhi, seqhi_len);
424 }
425 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
426 ahash_request_set_callback(req, 0, ah6_output_done, skb);
427
428 AH_SKB_CB(skb)->tmp = iph_base;
429
430 err = crypto_ahash_digest(req);
431 if (err) {
432 if (err == -EINPROGRESS)
433 goto out;
434
435 if (err == -ENOSPC)
436 err = NET_XMIT_DROP;
437 goto out_free;
438 }
439
440 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
441 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
442
443 if (extlen) {
444#if IS_ENABLED(CONFIG_IPV6_MIP6)
445 memcpy(&top_iph->saddr, iph_ext, extlen);
446#else
447 memcpy(&top_iph->daddr, iph_ext, extlen);
448#endif
449 }
450
451out_free:
452 kfree(iph_base);
453out:
454 return err;
455}
456
457static void ah6_input_done(struct crypto_async_request *base, int err)
458{
459 u8 *auth_data;
460 u8 *icv;
461 u8 *work_iph;
462 struct sk_buff *skb = base->data;
463 struct xfrm_state *x = xfrm_input_state(skb);
464 struct ah_data *ahp = x->data;
465 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
466 int hdr_len = skb_network_header_len(skb);
467 int ah_hlen = ipv6_authlen(ah);
468
469 if (err)
470 goto out;
471
472 work_iph = AH_SKB_CB(skb)->tmp;
473 auth_data = ah_tmp_auth(work_iph, hdr_len);
474 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
475
476 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
477 if (err)
478 goto out;
479
480 err = ah->nexthdr;
481
482 skb->network_header += ah_hlen;
483 memcpy(skb_network_header(skb), work_iph, hdr_len);
484 __skb_pull(skb, ah_hlen + hdr_len);
485 if (x->props.mode == XFRM_MODE_TUNNEL)
486 skb_reset_transport_header(skb);
487 else
488 skb_set_transport_header(skb, -hdr_len);
489out:
490 kfree(AH_SKB_CB(skb)->tmp);
491 xfrm_input_resume(skb, err);
492}
493
494
495
496static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
497{
498 /*
499 * Before process AH
500 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
501 * |<-------------->| hdr_len
502 *
503 * To erase AH:
504 * Keeping copy of cleared headers. After AH processing,
505 * Moving the pointer of skb->network_header by using skb_pull as long
506 * as AH header length. Then copy back the copy as long as hdr_len
507 * If destination header following AH exists, copy it into after [Ext2].
508 *
509 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
510 * There is offset of AH before IPv6 header after the process.
511 */
512
513 u8 *auth_data;
514 u8 *icv;
515 u8 *work_iph;
516 struct sk_buff *trailer;
517 struct crypto_ahash *ahash;
518 struct ahash_request *req;
519 struct scatterlist *sg;
520 struct ip_auth_hdr *ah;
521 struct ipv6hdr *ip6h;
522 struct ah_data *ahp;
523 u16 hdr_len;
524 u16 ah_hlen;
525 int nexthdr;
526 int nfrags;
527 int err = -ENOMEM;
528 int seqhi_len = 0;
529 __be32 *seqhi;
530 int sglists = 0;
531 struct scatterlist *seqhisg;
532
533 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
534 goto out;
535
536 /* We are going to _remove_ AH header to keep sockets happy,
537 * so... Later this can change. */
538 if (skb_unclone(skb, GFP_ATOMIC))
539 goto out;
540
541 skb->ip_summed = CHECKSUM_NONE;
542
543 hdr_len = skb_network_header_len(skb);
544 ah = (struct ip_auth_hdr *)skb->data;
545 ahp = x->data;
546 ahash = ahp->ahash;
547
548 nexthdr = ah->nexthdr;
549 ah_hlen = ipv6_authlen(ah);
550
551 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
552 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
553 goto out;
554
555 if (!pskb_may_pull(skb, ah_hlen))
556 goto out;
557
558 err = skb_cow_data(skb, 0, &trailer);
559 if (err < 0)
560 goto out;
561 nfrags = err;
562
563 ah = (struct ip_auth_hdr *)skb->data;
564 ip6h = ipv6_hdr(skb);
565
566 skb_push(skb, hdr_len);
567
568 if (x->props.flags & XFRM_STATE_ESN) {
569 sglists = 1;
570 seqhi_len = sizeof(*seqhi);
571 }
572
573 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len +
574 ahp->icv_trunc_len + seqhi_len);
575 if (!work_iph) {
576 err = -ENOMEM;
577 goto out;
578 }
579
580 auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len);
581 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len);
582 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
583 req = ah_tmp_req(ahash, icv);
584 sg = ah_req_sg(ahash, req);
585 seqhisg = sg + nfrags;
586
587 memcpy(work_iph, ip6h, hdr_len);
588 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
589 memset(ah->auth_data, 0, ahp->icv_trunc_len);
590
591 err = ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN);
592 if (err)
593 goto out_free;
594
595 ip6h->priority = 0;
596 ip6h->flow_lbl[0] = 0;
597 ip6h->flow_lbl[1] = 0;
598 ip6h->flow_lbl[2] = 0;
599 ip6h->hop_limit = 0;
600
601 sg_init_table(sg, nfrags + sglists);
602 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
603 if (unlikely(err < 0))
604 goto out_free;
605
606 if (x->props.flags & XFRM_STATE_ESN) {
607 /* Attach seqhi sg right after packet payload */
608 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
609 sg_set_buf(seqhisg, seqhi, seqhi_len);
610 }
611
612 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
613 ahash_request_set_callback(req, 0, ah6_input_done, skb);
614
615 AH_SKB_CB(skb)->tmp = work_iph;
616
617 err = crypto_ahash_digest(req);
618 if (err) {
619 if (err == -EINPROGRESS)
620 goto out;
621
622 goto out_free;
623 }
624
625 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
626 if (err)
627 goto out_free;
628
629 skb->network_header += ah_hlen;
630 memcpy(skb_network_header(skb), work_iph, hdr_len);
631 __skb_pull(skb, ah_hlen + hdr_len);
632
633 if (x->props.mode == XFRM_MODE_TUNNEL)
634 skb_reset_transport_header(skb);
635 else
636 skb_set_transport_header(skb, -hdr_len);
637
638 err = nexthdr;
639
640out_free:
641 kfree(work_iph);
642out:
643 return err;
644}
645
646static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
647 u8 type, u8 code, int offset, __be32 info)
648{
649 struct net *net = dev_net(skb->dev);
650 struct ipv6hdr *iph = (struct ipv6hdr *)skb->data;
651 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+offset);
652 struct xfrm_state *x;
653
654 if (type != ICMPV6_PKT_TOOBIG &&
655 type != NDISC_REDIRECT)
656 return 0;
657
658 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
659 if (!x)
660 return 0;
661
662 if (type == NDISC_REDIRECT)
663 ip6_redirect(skb, net, skb->dev->ifindex, 0,
664 sock_net_uid(net, NULL));
665 else
666 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
667 xfrm_state_put(x);
668
669 return 0;
670}
671
672static int ah6_init_state(struct xfrm_state *x)
673{
674 struct ah_data *ahp = NULL;
675 struct xfrm_algo_desc *aalg_desc;
676 struct crypto_ahash *ahash;
677
678 if (!x->aalg)
679 goto error;
680
681 if (x->encap)
682 goto error;
683
684 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
685 if (!ahp)
686 return -ENOMEM;
687
688 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
689 if (IS_ERR(ahash))
690 goto error;
691
692 ahp->ahash = ahash;
693 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
694 (x->aalg->alg_key_len + 7) / 8))
695 goto error;
696
697 /*
698 * Lookup the algorithm description maintained by xfrm_algo,
699 * verify crypto transform properties, and store information
700 * we need for AH processing. This lookup cannot fail here
701 * after a successful crypto_alloc_hash().
702 */
703 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
704 BUG_ON(!aalg_desc);
705
706 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
707 crypto_ahash_digestsize(ahash)) {
708 pr_info("AH: %s digestsize %u != %u\n",
709 x->aalg->alg_name, crypto_ahash_digestsize(ahash),
710 aalg_desc->uinfo.auth.icv_fullbits/8);
711 goto error;
712 }
713
714 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
715 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
716
717 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
718 ahp->icv_trunc_len);
719 switch (x->props.mode) {
720 case XFRM_MODE_BEET:
721 case XFRM_MODE_TRANSPORT:
722 break;
723 case XFRM_MODE_TUNNEL:
724 x->props.header_len += sizeof(struct ipv6hdr);
725 break;
726 default:
727 goto error;
728 }
729 x->data = ahp;
730
731 return 0;
732
733error:
734 if (ahp) {
735 crypto_free_ahash(ahp->ahash);
736 kfree(ahp);
737 }
738 return -EINVAL;
739}
740
741static void ah6_destroy(struct xfrm_state *x)
742{
743 struct ah_data *ahp = x->data;
744
745 if (!ahp)
746 return;
747
748 crypto_free_ahash(ahp->ahash);
749 kfree(ahp);
750}
751
752static int ah6_rcv_cb(struct sk_buff *skb, int err)
753{
754 return 0;
755}
756
757static const struct xfrm_type ah6_type = {
758 .owner = THIS_MODULE,
759 .proto = IPPROTO_AH,
760 .flags = XFRM_TYPE_REPLAY_PROT,
761 .init_state = ah6_init_state,
762 .destructor = ah6_destroy,
763 .input = ah6_input,
764 .output = ah6_output,
765};
766
767static struct xfrm6_protocol ah6_protocol = {
768 .handler = xfrm6_rcv,
769 .input_handler = xfrm_input,
770 .cb_handler = ah6_rcv_cb,
771 .err_handler = ah6_err,
772 .priority = 0,
773};
774
775static int __init ah6_init(void)
776{
777 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
778 pr_info("%s: can't add xfrm type\n", __func__);
779 return -EAGAIN;
780 }
781
782 if (xfrm6_protocol_register(&ah6_protocol, IPPROTO_AH) < 0) {
783 pr_info("%s: can't add protocol\n", __func__);
784 xfrm_unregister_type(&ah6_type, AF_INET6);
785 return -EAGAIN;
786 }
787
788 return 0;
789}
790
791static void __exit ah6_fini(void)
792{
793 if (xfrm6_protocol_deregister(&ah6_protocol, IPPROTO_AH) < 0)
794 pr_info("%s: can't remove protocol\n", __func__);
795
796 xfrm_unregister_type(&ah6_type, AF_INET6);
797}
798
799module_init(ah6_init);
800module_exit(ah6_fini);
801
802MODULE_LICENSE("GPL");
803MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);