2 * Copyright (C)2002 USAGI/WIDE Project
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.
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.
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
20 * Mitsuru KANDA @USAGI : IPv6 Support
21 * Kazunori MIYAZAWA @USAGI :
22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
24 * This file is derived from net/ipv4/ah.c.
27 #include <crypto/hash.h>
28 #include <linux/module.h>
29 #include <linux/slab.h>
32 #include <linux/crypto.h>
33 #include <linux/pfkeyv2.h>
34 #include <linux/string.h>
35 #include <linux/scatterlist.h>
38 #include <net/protocol.h>
41 #define IPV6HDR_BASELEN 8
44 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
45 struct in6_addr saddr
;
47 struct in6_addr daddr
;
52 struct xfrm_skb_cb xfrm
;
56 #define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
58 static void *ah_alloc_tmp(struct crypto_ahash
*ahash
, int nfrags
,
63 len
= size
+ crypto_ahash_digestsize(ahash
) +
64 (crypto_ahash_alignmask(ahash
) &
65 ~(crypto_tfm_ctx_alignment() - 1));
67 len
= ALIGN(len
, crypto_tfm_ctx_alignment());
69 len
+= sizeof(struct ahash_request
) + crypto_ahash_reqsize(ahash
);
70 len
= ALIGN(len
, __alignof__(struct scatterlist
));
72 len
+= sizeof(struct scatterlist
) * nfrags
;
74 return kmalloc(len
, GFP_ATOMIC
);
77 static inline struct tmp_ext
*ah_tmp_ext(void *base
)
79 return base
+ IPV6HDR_BASELEN
;
82 static inline u8
*ah_tmp_auth(u8
*tmp
, unsigned int offset
)
87 static inline u8
*ah_tmp_icv(struct crypto_ahash
*ahash
, void *tmp
,
90 return PTR_ALIGN((u8
*)tmp
+ offset
, crypto_ahash_alignmask(ahash
) + 1);
93 static inline struct ahash_request
*ah_tmp_req(struct crypto_ahash
*ahash
,
96 struct ahash_request
*req
;
98 req
= (void *)PTR_ALIGN(icv
+ crypto_ahash_digestsize(ahash
),
99 crypto_tfm_ctx_alignment());
101 ahash_request_set_tfm(req
, ahash
);
106 static inline struct scatterlist
*ah_req_sg(struct crypto_ahash
*ahash
,
107 struct ahash_request
*req
)
109 return (void *)ALIGN((unsigned long)(req
+ 1) +
110 crypto_ahash_reqsize(ahash
),
111 __alignof__(struct scatterlist
));
114 static int zero_out_mutable_opts(struct ipv6_opt_hdr
*opthdr
)
116 u8
*opt
= (u8
*)opthdr
;
117 int len
= ipv6_optlen(opthdr
);
134 optlen
= opt
[off
+1]+2;
138 memset(&opt
[off
+2], 0, opt
[off
+1]);
152 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
154 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
156 * @destopt: destionation options header
158 static void ipv6_rearrange_destopt(struct ipv6hdr
*iph
, struct ipv6_opt_hdr
*destopt
)
160 u8
*opt
= (u8
*)destopt
;
161 int len
= ipv6_optlen(destopt
);
178 optlen
= opt
[off
+1]+2;
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.
186 if (opt
[off
] == IPV6_TLV_HAO
) {
187 struct in6_addr final_addr
;
188 struct ipv6_destopt_hao
*hao
;
190 hao
= (struct ipv6_destopt_hao
*)&opt
[off
];
191 if (hao
->length
!= sizeof(hao
->addr
)) {
193 printk(KERN_WARNING
"destopt hao: invalid header length: %u\n", hao
->length
);
196 ipv6_addr_copy(&final_addr
, &hao
->addr
);
197 ipv6_addr_copy(&hao
->addr
, &iph
->saddr
);
198 ipv6_addr_copy(&iph
->saddr
, &final_addr
);
206 /* Note: ok if len == 0 */
211 static void ipv6_rearrange_destopt(struct ipv6hdr
*iph
, struct ipv6_opt_hdr
*destopt
) {}
215 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
217 * @rthdr: routing header
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.
223 static void ipv6_rearrange_rthdr(struct ipv6hdr
*iph
, struct ipv6_rt_hdr
*rthdr
)
225 int segments
, segments_left
;
226 struct in6_addr
*addrs
;
227 struct in6_addr final_addr
;
229 segments_left
= rthdr
->segments_left
;
230 if (segments_left
== 0)
232 rthdr
->segments_left
= 0;
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.
239 * For the same reason we can assume that this option is of type 0.
241 segments
= rthdr
->hdrlen
>> 1;
243 addrs
= ((struct rt0_hdr
*)rthdr
)->addr
;
244 ipv6_addr_copy(&final_addr
, addrs
+ segments
- 1);
246 addrs
+= segments
- segments_left
;
247 memmove(addrs
+ 1, addrs
, (segments_left
- 1) * sizeof(*addrs
));
249 ipv6_addr_copy(addrs
, &iph
->daddr
);
250 ipv6_addr_copy(&iph
->daddr
, &final_addr
);
253 static int ipv6_clear_mutable_options(struct ipv6hdr
*iph
, int len
, int dir
)
257 struct ipv6_opt_hdr
*opth
;
258 struct ipv6_rt_hdr
*rth
;
260 } exthdr
= { .iph
= iph
};
261 char *end
= exthdr
.raw
+ len
;
262 int nexthdr
= iph
->nexthdr
;
266 while (exthdr
.raw
< end
) {
269 if (dir
== XFRM_POLICY_OUT
)
270 ipv6_rearrange_destopt(iph
, exthdr
.opth
);
272 if (!zero_out_mutable_opts(exthdr
.opth
)) {
274 KERN_WARNING
"overrun %sopts\n",
275 nexthdr
== NEXTHDR_HOP
?
281 case NEXTHDR_ROUTING
:
282 ipv6_rearrange_rthdr(iph
, exthdr
.rth
);
289 nexthdr
= exthdr
.opth
->nexthdr
;
290 exthdr
.raw
+= ipv6_optlen(exthdr
.opth
);
296 static void ah6_output_done(struct crypto_async_request
*base
, int err
)
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
;
308 extlen
= skb_network_header_len(skb
) - sizeof(struct ipv6hdr
);
310 extlen
+= sizeof(*iph_ext
);
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
);
316 memcpy(ah
->auth_data
, icv
, ahp
->icv_trunc_len
);
317 memcpy(top_iph
, iph_base
, IPV6HDR_BASELEN
);
320 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
321 memcpy(&top_iph
->saddr
, iph_ext
, extlen
);
323 memcpy(&top_iph
->daddr
, iph_ext
, extlen
);
327 kfree(AH_SKB_CB(skb
)->tmp
);
328 xfrm_output_resume(skb
, err
);
331 static int ah6_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
339 struct sk_buff
*trailer
;
340 struct crypto_ahash
*ahash
;
341 struct ahash_request
*req
;
342 struct scatterlist
*sg
;
343 struct ipv6hdr
*top_iph
;
344 struct ip_auth_hdr
*ah
;
346 struct tmp_ext
*iph_ext
;
351 if ((err
= skb_cow_data(skb
, 0, &trailer
)) < 0)
355 skb_push(skb
, -skb_network_offset(skb
));
356 extlen
= skb_network_header_len(skb
) - sizeof(struct ipv6hdr
);
358 extlen
+= sizeof(*iph_ext
);
361 iph_base
= ah_alloc_tmp(ahash
, nfrags
, IPV6HDR_BASELEN
+ extlen
);
365 iph_ext
= ah_tmp_ext(iph_base
);
366 icv
= ah_tmp_icv(ahash
, iph_ext
, extlen
);
367 req
= ah_tmp_req(ahash
, icv
);
368 sg
= ah_req_sg(ahash
, req
);
370 ah
= ip_auth_hdr(skb
);
371 memset(ah
->auth_data
, 0, ahp
->icv_trunc_len
);
373 top_iph
= ipv6_hdr(skb
);
374 top_iph
->payload_len
= htons(skb
->len
- sizeof(*top_iph
));
376 nexthdr
= *skb_mac_header(skb
);
377 *skb_mac_header(skb
) = IPPROTO_AH
;
379 /* When there are no extension headers, we only need to save the first
380 * 8 bytes of the base IP header.
382 memcpy(iph_base
, top_iph
, IPV6HDR_BASELEN
);
385 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
386 memcpy(iph_ext
, &top_iph
->saddr
, extlen
);
388 memcpy(iph_ext
, &top_iph
->daddr
, extlen
);
390 err
= ipv6_clear_mutable_options(top_iph
,
391 extlen
- sizeof(*iph_ext
) +
398 ah
->nexthdr
= nexthdr
;
400 top_iph
->priority
= 0;
401 top_iph
->flow_lbl
[0] = 0;
402 top_iph
->flow_lbl
[1] = 0;
403 top_iph
->flow_lbl
[2] = 0;
404 top_iph
->hop_limit
= 0;
406 ah
->hdrlen
= (XFRM_ALIGN8(sizeof(*ah
) + ahp
->icv_trunc_len
) >> 2) - 2;
410 ah
->seq_no
= htonl(XFRM_SKB_CB(skb
)->seq
.output
.low
);
412 sg_init_table(sg
, nfrags
);
413 skb_to_sgvec(skb
, sg
, 0, skb
->len
);
415 ahash_request_set_crypt(req
, sg
, icv
, skb
->len
);
416 ahash_request_set_callback(req
, 0, ah6_output_done
, skb
);
418 AH_SKB_CB(skb
)->tmp
= iph_base
;
420 err
= crypto_ahash_digest(req
);
422 if (err
== -EINPROGRESS
)
430 memcpy(ah
->auth_data
, icv
, ahp
->icv_trunc_len
);
431 memcpy(top_iph
, iph_base
, IPV6HDR_BASELEN
);
434 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
435 memcpy(&top_iph
->saddr
, iph_ext
, extlen
);
437 memcpy(&top_iph
->daddr
, iph_ext
, extlen
);
447 static void ah6_input_done(struct crypto_async_request
*base
, int err
)
452 struct sk_buff
*skb
= base
->data
;
453 struct xfrm_state
*x
= xfrm_input_state(skb
);
454 struct ah_data
*ahp
= x
->data
;
455 struct ip_auth_hdr
*ah
= ip_auth_hdr(skb
);
456 int hdr_len
= skb_network_header_len(skb
);
457 int ah_hlen
= (ah
->hdrlen
+ 2) << 2;
459 work_iph
= AH_SKB_CB(skb
)->tmp
;
460 auth_data
= ah_tmp_auth(work_iph
, hdr_len
);
461 icv
= ah_tmp_icv(ahp
->ahash
, auth_data
, ahp
->icv_trunc_len
);
463 err
= memcmp(icv
, auth_data
, ahp
->icv_trunc_len
) ? -EBADMSG
: 0;
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
);
474 kfree(AH_SKB_CB(skb
)->tmp
);
475 xfrm_input_resume(skb
, err
);
480 static int ah6_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
484 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
485 * |<-------------->| hdr_len
488 * Keeping copy of cleared headers. After AH processing,
489 * Moving the pointer of skb->network_header by using skb_pull as long
490 * as AH header length. Then copy back the copy as long as hdr_len
491 * If destination header following AH exists, copy it into after [Ext2].
493 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
494 * There is offset of AH before IPv6 header after the process.
500 struct sk_buff
*trailer
;
501 struct crypto_ahash
*ahash
;
502 struct ahash_request
*req
;
503 struct scatterlist
*sg
;
504 struct ip_auth_hdr
*ah
;
505 struct ipv6hdr
*ip6h
;
513 if (!pskb_may_pull(skb
, sizeof(struct ip_auth_hdr
)))
516 /* We are going to _remove_ AH header to keep sockets happy,
517 * so... Later this can change. */
518 if (skb_cloned(skb
) &&
519 pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
))
522 skb
->ip_summed
= CHECKSUM_NONE
;
524 hdr_len
= skb_network_header_len(skb
);
525 ah
= (struct ip_auth_hdr
*)skb
->data
;
529 nexthdr
= ah
->nexthdr
;
530 ah_hlen
= (ah
->hdrlen
+ 2) << 2;
532 if (ah_hlen
!= XFRM_ALIGN8(sizeof(*ah
) + ahp
->icv_full_len
) &&
533 ah_hlen
!= XFRM_ALIGN8(sizeof(*ah
) + ahp
->icv_trunc_len
))
536 if (!pskb_may_pull(skb
, ah_hlen
))
540 if ((err
= skb_cow_data(skb
, 0, &trailer
)) < 0)
544 ah
= (struct ip_auth_hdr
*)skb
->data
;
545 ip6h
= ipv6_hdr(skb
);
547 skb_push(skb
, hdr_len
);
549 work_iph
= ah_alloc_tmp(ahash
, nfrags
, hdr_len
+ ahp
->icv_trunc_len
);
553 auth_data
= ah_tmp_auth(work_iph
, hdr_len
);
554 icv
= ah_tmp_icv(ahash
, auth_data
, ahp
->icv_trunc_len
);
555 req
= ah_tmp_req(ahash
, icv
);
556 sg
= ah_req_sg(ahash
, req
);
558 memcpy(work_iph
, ip6h
, hdr_len
);
559 memcpy(auth_data
, ah
->auth_data
, ahp
->icv_trunc_len
);
560 memset(ah
->auth_data
, 0, ahp
->icv_trunc_len
);
562 if (ipv6_clear_mutable_options(ip6h
, hdr_len
, XFRM_POLICY_IN
))
566 ip6h
->flow_lbl
[0] = 0;
567 ip6h
->flow_lbl
[1] = 0;
568 ip6h
->flow_lbl
[2] = 0;
571 sg_init_table(sg
, nfrags
);
572 skb_to_sgvec(skb
, sg
, 0, skb
->len
);
574 ahash_request_set_crypt(req
, sg
, icv
, skb
->len
);
575 ahash_request_set_callback(req
, 0, ah6_input_done
, skb
);
577 AH_SKB_CB(skb
)->tmp
= work_iph
;
579 err
= crypto_ahash_digest(req
);
581 if (err
== -EINPROGRESS
)
587 err
= memcmp(icv
, auth_data
, ahp
->icv_trunc_len
) ? -EBADMSG
: 0;
591 skb
->network_header
+= ah_hlen
;
592 memcpy(skb_network_header(skb
), work_iph
, hdr_len
);
593 skb
->transport_header
= skb
->network_header
;
594 __skb_pull(skb
, ah_hlen
+ hdr_len
);
604 static void ah6_err(struct sk_buff
*skb
, struct inet6_skb_parm
*opt
,
605 u8 type
, u8 code
, int offset
, __be32 info
)
607 struct net
*net
= dev_net(skb
->dev
);
608 struct ipv6hdr
*iph
= (struct ipv6hdr
*)skb
->data
;
609 struct ip_auth_hdr
*ah
= (struct ip_auth_hdr
*)(skb
->data
+offset
);
610 struct xfrm_state
*x
;
612 if (type
!= ICMPV6_DEST_UNREACH
&&
613 type
!= ICMPV6_PKT_TOOBIG
)
616 x
= xfrm_state_lookup(net
, skb
->mark
, (xfrm_address_t
*)&iph
->daddr
, ah
->spi
, IPPROTO_AH
, AF_INET6
);
620 NETDEBUG(KERN_DEBUG
"pmtu discovery on SA AH/%08x/%pI6\n",
621 ntohl(ah
->spi
), &iph
->daddr
);
626 static int ah6_init_state(struct xfrm_state
*x
)
628 struct ah_data
*ahp
= NULL
;
629 struct xfrm_algo_desc
*aalg_desc
;
630 struct crypto_ahash
*ahash
;
638 ahp
= kzalloc(sizeof(*ahp
), GFP_KERNEL
);
642 ahash
= crypto_alloc_ahash(x
->aalg
->alg_name
, 0, 0);
647 if (crypto_ahash_setkey(ahash
, x
->aalg
->alg_key
,
648 (x
->aalg
->alg_key_len
+ 7) / 8))
652 * Lookup the algorithm description maintained by xfrm_algo,
653 * verify crypto transform properties, and store information
654 * we need for AH processing. This lookup cannot fail here
655 * after a successful crypto_alloc_hash().
657 aalg_desc
= xfrm_aalg_get_byname(x
->aalg
->alg_name
, 0);
660 if (aalg_desc
->uinfo
.auth
.icv_fullbits
/8 !=
661 crypto_ahash_digestsize(ahash
)) {
662 printk(KERN_INFO
"AH: %s digestsize %u != %hu\n",
663 x
->aalg
->alg_name
, crypto_ahash_digestsize(ahash
),
664 aalg_desc
->uinfo
.auth
.icv_fullbits
/8);
668 ahp
->icv_full_len
= aalg_desc
->uinfo
.auth
.icv_fullbits
/8;
669 ahp
->icv_trunc_len
= x
->aalg
->alg_trunc_len
/8;
671 BUG_ON(ahp
->icv_trunc_len
> MAX_AH_AUTH_LEN
);
673 x
->props
.header_len
= XFRM_ALIGN8(sizeof(struct ip_auth_hdr
) +
675 switch (x
->props
.mode
) {
677 case XFRM_MODE_TRANSPORT
:
679 case XFRM_MODE_TUNNEL
:
680 x
->props
.header_len
+= sizeof(struct ipv6hdr
);
691 crypto_free_ahash(ahp
->ahash
);
697 static void ah6_destroy(struct xfrm_state
*x
)
699 struct ah_data
*ahp
= x
->data
;
704 crypto_free_ahash(ahp
->ahash
);
708 static const struct xfrm_type ah6_type
=
710 .description
= "AH6",
711 .owner
= THIS_MODULE
,
713 .flags
= XFRM_TYPE_REPLAY_PROT
,
714 .init_state
= ah6_init_state
,
715 .destructor
= ah6_destroy
,
717 .output
= ah6_output
,
718 .hdr_offset
= xfrm6_find_1stfragopt
,
721 static const struct inet6_protocol ah6_protocol
= {
722 .handler
= xfrm6_rcv
,
723 .err_handler
= ah6_err
,
724 .flags
= INET6_PROTO_NOPOLICY
,
727 static int __init
ah6_init(void)
729 if (xfrm_register_type(&ah6_type
, AF_INET6
) < 0) {
730 printk(KERN_INFO
"ipv6 ah init: can't add xfrm type\n");
734 if (inet6_add_protocol(&ah6_protocol
, IPPROTO_AH
) < 0) {
735 printk(KERN_INFO
"ipv6 ah init: can't add protocol\n");
736 xfrm_unregister_type(&ah6_type
, AF_INET6
);
743 static void __exit
ah6_fini(void)
745 if (inet6_del_protocol(&ah6_protocol
, IPPROTO_AH
) < 0)
746 printk(KERN_INFO
"ipv6 ah close: can't remove protocol\n");
748 if (xfrm_unregister_type(&ah6_type
, AF_INET6
) < 0)
749 printk(KERN_INFO
"ipv6 ah close: can't remove xfrm type\n");
753 module_init(ah6_init
);
754 module_exit(ah6_fini
);
756 MODULE_LICENSE("GPL");
757 MODULE_ALIAS_XFRM_TYPE(AF_INET6
, XFRM_PROTO_AH
);