1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C)2002 USAGI/WIDE Project
7 * Mitsuru KANDA @USAGI : IPv6 Support
8 * Kazunori MIYAZAWA @USAGI :
9 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
11 * This file is derived from net/ipv4/ah.c.
14 #define pr_fmt(fmt) "IPv6: " fmt
16 #include <crypto/algapi.h>
17 #include <crypto/hash.h>
18 #include <linux/module.h>
19 #include <linux/slab.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>
29 #include <net/protocol.h>
32 #define IPV6HDR_BASELEN 8
35 #if IS_ENABLED(CONFIG_IPV6_MIP6)
36 struct in6_addr saddr
;
38 struct in6_addr daddr
;
43 struct xfrm_skb_cb xfrm
;
47 #define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
49 static void *ah_alloc_tmp(struct crypto_ahash
*ahash
, int nfrags
,
54 len
= size
+ crypto_ahash_digestsize(ahash
) +
55 (crypto_ahash_alignmask(ahash
) &
56 ~(crypto_tfm_ctx_alignment() - 1));
58 len
= ALIGN(len
, crypto_tfm_ctx_alignment());
60 len
+= sizeof(struct ahash_request
) + crypto_ahash_reqsize(ahash
);
61 len
= ALIGN(len
, __alignof__(struct scatterlist
));
63 len
+= sizeof(struct scatterlist
) * nfrags
;
65 return kmalloc(len
, GFP_ATOMIC
);
68 static inline struct tmp_ext
*ah_tmp_ext(void *base
)
70 return base
+ IPV6HDR_BASELEN
;
73 static inline u8
*ah_tmp_auth(u8
*tmp
, unsigned int offset
)
78 static inline u8
*ah_tmp_icv(struct crypto_ahash
*ahash
, void *tmp
,
81 return PTR_ALIGN((u8
*)tmp
+ offset
, crypto_ahash_alignmask(ahash
) + 1);
84 static inline struct ahash_request
*ah_tmp_req(struct crypto_ahash
*ahash
,
87 struct ahash_request
*req
;
89 req
= (void *)PTR_ALIGN(icv
+ crypto_ahash_digestsize(ahash
),
90 crypto_tfm_ctx_alignment());
92 ahash_request_set_tfm(req
, ahash
);
97 static inline struct scatterlist
*ah_req_sg(struct crypto_ahash
*ahash
,
98 struct ahash_request
*req
)
100 return (void *)ALIGN((unsigned long)(req
+ 1) +
101 crypto_ahash_reqsize(ahash
),
102 __alignof__(struct scatterlist
));
105 static bool zero_out_mutable_opts(struct ipv6_opt_hdr
*opthdr
)
107 u8
*opt
= (u8
*)opthdr
;
108 int len
= ipv6_optlen(opthdr
);
125 optlen
= opt
[off
+1]+2;
129 memset(&opt
[off
+2], 0, opt
[off
+1]);
143 #if IS_ENABLED(CONFIG_IPV6_MIP6)
145 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
147 * @destopt: destionation options header
149 static void ipv6_rearrange_destopt(struct ipv6hdr
*iph
, struct ipv6_opt_hdr
*destopt
)
151 u8
*opt
= (u8
*)destopt
;
152 int len
= ipv6_optlen(destopt
);
169 optlen
= opt
[off
+1]+2;
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.
177 if (opt
[off
] == IPV6_TLV_HAO
) {
178 struct in6_addr final_addr
;
179 struct ipv6_destopt_hao
*hao
;
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",
187 final_addr
= hao
->addr
;
188 hao
->addr
= iph
->saddr
;
189 iph
->saddr
= final_addr
;
197 /* Note: ok if len == 0 */
202 static void ipv6_rearrange_destopt(struct ipv6hdr
*iph
, struct ipv6_opt_hdr
*destopt
) {}
206 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
208 * @rthdr: routing header
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.
214 static void ipv6_rearrange_rthdr(struct ipv6hdr
*iph
, struct ipv6_rt_hdr
*rthdr
)
216 int segments
, segments_left
;
217 struct in6_addr
*addrs
;
218 struct in6_addr final_addr
;
220 segments_left
= rthdr
->segments_left
;
221 if (segments_left
== 0)
223 rthdr
->segments_left
= 0;
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.
230 * For the same reason we can assume that this option is of type 0.
232 segments
= rthdr
->hdrlen
>> 1;
234 addrs
= ((struct rt0_hdr
*)rthdr
)->addr
;
235 final_addr
= addrs
[segments
- 1];
237 addrs
+= segments
- segments_left
;
238 memmove(addrs
+ 1, addrs
, (segments_left
- 1) * sizeof(*addrs
));
240 addrs
[0] = iph
->daddr
;
241 iph
->daddr
= final_addr
;
244 static int ipv6_clear_mutable_options(struct ipv6hdr
*iph
, int len
, int dir
)
248 struct ipv6_opt_hdr
*opth
;
249 struct ipv6_rt_hdr
*rth
;
251 } exthdr
= { .iph
= iph
};
252 char *end
= exthdr
.raw
+ len
;
253 int nexthdr
= iph
->nexthdr
;
257 while (exthdr
.raw
< end
) {
260 if (dir
== XFRM_POLICY_OUT
)
261 ipv6_rearrange_destopt(iph
, exthdr
.opth
);
264 if (!zero_out_mutable_opts(exthdr
.opth
)) {
265 net_dbg_ratelimited("overrun %sopts\n",
266 nexthdr
== NEXTHDR_HOP
?
272 case NEXTHDR_ROUTING
:
273 ipv6_rearrange_rthdr(iph
, exthdr
.rth
);
280 nexthdr
= exthdr
.opth
->nexthdr
;
281 exthdr
.raw
+= ipv6_optlen(exthdr
.opth
);
287 static void ah6_output_done(struct crypto_async_request
*base
, int err
)
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
;
299 extlen
= skb_network_header_len(skb
) - sizeof(struct ipv6hdr
);
301 extlen
+= sizeof(*iph_ext
);
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
);
307 memcpy(ah
->auth_data
, icv
, ahp
->icv_trunc_len
);
308 memcpy(top_iph
, iph_base
, IPV6HDR_BASELEN
);
311 #if IS_ENABLED(CONFIG_IPV6_MIP6)
312 memcpy(&top_iph
->saddr
, iph_ext
, extlen
);
314 memcpy(&top_iph
->daddr
, iph_ext
, extlen
);
318 kfree(AH_SKB_CB(skb
)->tmp
);
319 xfrm_output_resume(skb
, err
);
322 static int ah6_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
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
;
337 struct tmp_ext
*iph_ext
;
341 struct scatterlist
*seqhisg
;
346 err
= skb_cow_data(skb
, 0, &trailer
);
351 skb_push(skb
, -skb_network_offset(skb
));
352 extlen
= skb_network_header_len(skb
) - sizeof(struct ipv6hdr
);
354 extlen
+= sizeof(*iph_ext
);
356 if (x
->props
.flags
& XFRM_STATE_ESN
) {
358 seqhi_len
= sizeof(*seqhi
);
361 iph_base
= ah_alloc_tmp(ahash
, nfrags
+ sglists
, IPV6HDR_BASELEN
+
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
;
373 ah
= ip_auth_hdr(skb
);
374 memset(ah
->auth_data
, 0, ahp
->icv_trunc_len
);
376 top_iph
= ipv6_hdr(skb
);
377 top_iph
->payload_len
= htons(skb
->len
- sizeof(*top_iph
));
379 nexthdr
= *skb_mac_header(skb
);
380 *skb_mac_header(skb
) = IPPROTO_AH
;
382 /* When there are no extension headers, we only need to save the first
383 * 8 bytes of the base IP header.
385 memcpy(iph_base
, top_iph
, IPV6HDR_BASELEN
);
388 #if IS_ENABLED(CONFIG_IPV6_MIP6)
389 memcpy(iph_ext
, &top_iph
->saddr
, extlen
);
391 memcpy(iph_ext
, &top_iph
->daddr
, extlen
);
393 err
= ipv6_clear_mutable_options(top_iph
,
394 extlen
- sizeof(*iph_ext
) +
401 ah
->nexthdr
= nexthdr
;
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;
409 ah
->hdrlen
= (XFRM_ALIGN8(sizeof(*ah
) + ahp
->icv_trunc_len
) >> 2) - 2;
413 ah
->seq_no
= htonl(XFRM_SKB_CB(skb
)->seq
.output
.low
);
415 sg_init_table(sg
, nfrags
+ sglists
);
416 err
= skb_to_sgvec_nomark(skb
, sg
, 0, skb
->len
);
417 if (unlikely(err
< 0))
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
);
425 ahash_request_set_crypt(req
, sg
, icv
, skb
->len
+ seqhi_len
);
426 ahash_request_set_callback(req
, 0, ah6_output_done
, skb
);
428 AH_SKB_CB(skb
)->tmp
= iph_base
;
430 err
= crypto_ahash_digest(req
);
432 if (err
== -EINPROGRESS
)
440 memcpy(ah
->auth_data
, icv
, ahp
->icv_trunc_len
);
441 memcpy(top_iph
, iph_base
, IPV6HDR_BASELEN
);
444 #if IS_ENABLED(CONFIG_IPV6_MIP6)
445 memcpy(&top_iph
->saddr
, iph_ext
, extlen
);
447 memcpy(&top_iph
->daddr
, iph_ext
, extlen
);
457 static void ah6_input_done(struct crypto_async_request
*base
, int err
)
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
);
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
);
476 err
= crypto_memneq(icv
, auth_data
, ahp
->icv_trunc_len
) ? -EBADMSG
: 0;
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
);
488 skb_set_transport_header(skb
, -hdr_len
);
490 kfree(AH_SKB_CB(skb
)->tmp
);
491 xfrm_input_resume(skb
, err
);
496 static int ah6_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
500 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
501 * |<-------------->| hdr_len
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].
509 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
510 * There is offset of AH before IPv6 header after the process.
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
;
531 struct scatterlist
*seqhisg
;
533 if (!pskb_may_pull(skb
, sizeof(struct ip_auth_hdr
)))
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
))
541 skb
->ip_summed
= CHECKSUM_NONE
;
543 hdr_len
= skb_network_header_len(skb
);
544 ah
= (struct ip_auth_hdr
*)skb
->data
;
548 nexthdr
= ah
->nexthdr
;
549 ah_hlen
= ipv6_authlen(ah
);
551 if (ah_hlen
!= XFRM_ALIGN8(sizeof(*ah
) + ahp
->icv_full_len
) &&
552 ah_hlen
!= XFRM_ALIGN8(sizeof(*ah
) + ahp
->icv_trunc_len
))
555 if (!pskb_may_pull(skb
, ah_hlen
))
558 err
= skb_cow_data(skb
, 0, &trailer
);
563 ah
= (struct ip_auth_hdr
*)skb
->data
;
564 ip6h
= ipv6_hdr(skb
);
566 skb_push(skb
, hdr_len
);
568 if (x
->props
.flags
& XFRM_STATE_ESN
) {
570 seqhi_len
= sizeof(*seqhi
);
573 work_iph
= ah_alloc_tmp(ahash
, nfrags
+ sglists
, hdr_len
+
574 ahp
->icv_trunc_len
+ seqhi_len
);
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
;
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
);
591 if (ipv6_clear_mutable_options(ip6h
, hdr_len
, XFRM_POLICY_IN
))
595 ip6h
->flow_lbl
[0] = 0;
596 ip6h
->flow_lbl
[1] = 0;
597 ip6h
->flow_lbl
[2] = 0;
600 sg_init_table(sg
, nfrags
+ sglists
);
601 err
= skb_to_sgvec_nomark(skb
, sg
, 0, skb
->len
);
602 if (unlikely(err
< 0))
605 if (x
->props
.flags
& XFRM_STATE_ESN
) {
606 /* Attach seqhi sg right after packet payload */
607 *seqhi
= XFRM_SKB_CB(skb
)->seq
.input
.hi
;
608 sg_set_buf(seqhisg
, seqhi
, seqhi_len
);
611 ahash_request_set_crypt(req
, sg
, icv
, skb
->len
+ seqhi_len
);
612 ahash_request_set_callback(req
, 0, ah6_input_done
, skb
);
614 AH_SKB_CB(skb
)->tmp
= work_iph
;
616 err
= crypto_ahash_digest(req
);
618 if (err
== -EINPROGRESS
)
624 err
= crypto_memneq(icv
, auth_data
, ahp
->icv_trunc_len
) ? -EBADMSG
: 0;
628 skb
->network_header
+= ah_hlen
;
629 memcpy(skb_network_header(skb
), work_iph
, hdr_len
);
630 __skb_pull(skb
, ah_hlen
+ hdr_len
);
632 if (x
->props
.mode
== XFRM_MODE_TUNNEL
)
633 skb_reset_transport_header(skb
);
635 skb_set_transport_header(skb
, -hdr_len
);
645 static int ah6_err(struct sk_buff
*skb
, struct inet6_skb_parm
*opt
,
646 u8 type
, u8 code
, int offset
, __be32 info
)
648 struct net
*net
= dev_net(skb
->dev
);
649 struct ipv6hdr
*iph
= (struct ipv6hdr
*)skb
->data
;
650 struct ip_auth_hdr
*ah
= (struct ip_auth_hdr
*)(skb
->data
+offset
);
651 struct xfrm_state
*x
;
653 if (type
!= ICMPV6_PKT_TOOBIG
&&
654 type
!= NDISC_REDIRECT
)
657 x
= xfrm_state_lookup(net
, skb
->mark
, (xfrm_address_t
*)&iph
->daddr
, ah
->spi
, IPPROTO_AH
, AF_INET6
);
661 if (type
== NDISC_REDIRECT
)
662 ip6_redirect(skb
, net
, skb
->dev
->ifindex
, 0,
663 sock_net_uid(net
, NULL
));
665 ip6_update_pmtu(skb
, net
, info
, 0, 0, sock_net_uid(net
, NULL
));
671 static int ah6_init_state(struct xfrm_state
*x
)
673 struct ah_data
*ahp
= NULL
;
674 struct xfrm_algo_desc
*aalg_desc
;
675 struct crypto_ahash
*ahash
;
683 ahp
= kzalloc(sizeof(*ahp
), GFP_KERNEL
);
687 ahash
= crypto_alloc_ahash(x
->aalg
->alg_name
, 0, 0);
692 if (crypto_ahash_setkey(ahash
, x
->aalg
->alg_key
,
693 (x
->aalg
->alg_key_len
+ 7) / 8))
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().
702 aalg_desc
= xfrm_aalg_get_byname(x
->aalg
->alg_name
, 0);
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);
713 ahp
->icv_full_len
= aalg_desc
->uinfo
.auth
.icv_fullbits
/8;
714 ahp
->icv_trunc_len
= x
->aalg
->alg_trunc_len
/8;
716 x
->props
.header_len
= XFRM_ALIGN8(sizeof(struct ip_auth_hdr
) +
718 switch (x
->props
.mode
) {
720 case XFRM_MODE_TRANSPORT
:
722 case XFRM_MODE_TUNNEL
:
723 x
->props
.header_len
+= sizeof(struct ipv6hdr
);
734 crypto_free_ahash(ahp
->ahash
);
740 static void ah6_destroy(struct xfrm_state
*x
)
742 struct ah_data
*ahp
= x
->data
;
747 crypto_free_ahash(ahp
->ahash
);
751 static int ah6_rcv_cb(struct sk_buff
*skb
, int err
)
756 static const struct xfrm_type ah6_type
= {
757 .description
= "AH6",
758 .owner
= THIS_MODULE
,
760 .flags
= XFRM_TYPE_REPLAY_PROT
,
761 .init_state
= ah6_init_state
,
762 .destructor
= ah6_destroy
,
764 .output
= ah6_output
,
765 .hdr_offset
= xfrm6_find_1stfragopt
,
768 static struct xfrm6_protocol ah6_protocol
= {
769 .handler
= xfrm6_rcv
,
770 .cb_handler
= ah6_rcv_cb
,
771 .err_handler
= ah6_err
,
775 static int __init
ah6_init(void)
777 if (xfrm_register_type(&ah6_type
, AF_INET6
) < 0) {
778 pr_info("%s: can't add xfrm type\n", __func__
);
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
);
791 static void __exit
ah6_fini(void)
793 if (xfrm6_protocol_deregister(&ah6_protocol
, IPPROTO_AH
) < 0)
794 pr_info("%s: can't remove protocol\n", __func__
);
796 xfrm_unregister_type(&ah6_type
, AF_INET6
);
799 module_init(ah6_init
);
800 module_exit(ah6_fini
);
802 MODULE_LICENSE("GPL");
803 MODULE_ALIAS_XFRM_TYPE(AF_INET6
, XFRM_PROTO_AH
);