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