xref: /openbmc/linux/net/ipv6/ah6.c (revision b9ccfda2)
1 /*
2  * Copyright (C)2002 USAGI/WIDE Project
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17  *
18  * Authors
19  *
20  *	Mitsuru KANDA @USAGI       : IPv6 Support
21  * 	Kazunori MIYAZAWA @USAGI   :
22  * 	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
23  *
24  * 	This file is derived from net/ipv4/ah.c.
25  */
26 
27 #define pr_fmt(fmt) "IPv6: " fmt
28 
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 
46 struct tmp_ext {
47 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
48 		struct in6_addr saddr;
49 #endif
50 		struct in6_addr daddr;
51 		char hdrs[0];
52 };
53 
54 struct 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 
61 static 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 
80 static inline struct tmp_ext *ah_tmp_ext(void *base)
81 {
82 	return base + IPV6HDR_BASELEN;
83 }
84 
85 static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
86 {
87 	return tmp + offset;
88 }
89 
90 static 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 
96 static 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 
109 static 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 
117 static 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 
151 bad:
152 	return false;
153 }
154 
155 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
156 /**
157  *	ipv6_rearrange_destopt - rearrange IPv6 destination options header
158  *	@iph: IPv6 header
159  *	@destopt: destionation options header
160  */
161 static 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 */
210 bad:
211 	return;
212 }
213 #else
214 static 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  */
226 static 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 
256 static 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 		case NEXTHDR_HOP:
275 			if (!zero_out_mutable_opts(exthdr.opth)) {
276 				LIMIT_NETDEBUG(
277 					KERN_WARNING "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 
299 static 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 defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
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 
334 static 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 
351 	ahp = x->data;
352 	ahash = ahp->ahash;
353 
354 	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
355 		goto out;
356 	nfrags = err;
357 
358 	skb_push(skb, -skb_network_offset(skb));
359 	extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
360 	if (extlen)
361 		extlen += sizeof(*iph_ext);
362 
363 	err = -ENOMEM;
364 	iph_base = ah_alloc_tmp(ahash, nfrags, IPV6HDR_BASELEN + extlen);
365 	if (!iph_base)
366 		goto out;
367 
368 	iph_ext = ah_tmp_ext(iph_base);
369 	icv = ah_tmp_icv(ahash, iph_ext, extlen);
370 	req = ah_tmp_req(ahash, icv);
371 	sg = ah_req_sg(ahash, req);
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 defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
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);
416 	skb_to_sgvec(skb, sg, 0, skb->len);
417 
418 	ahash_request_set_crypt(req, sg, icv, skb->len);
419 	ahash_request_set_callback(req, 0, ah6_output_done, skb);
420 
421 	AH_SKB_CB(skb)->tmp = iph_base;
422 
423 	err = crypto_ahash_digest(req);
424 	if (err) {
425 		if (err == -EINPROGRESS)
426 			goto out;
427 
428 		if (err == -EBUSY)
429 			err = NET_XMIT_DROP;
430 		goto out_free;
431 	}
432 
433 	memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
434 	memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
435 
436 	if (extlen) {
437 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
438 		memcpy(&top_iph->saddr, iph_ext, extlen);
439 #else
440 		memcpy(&top_iph->daddr, iph_ext, extlen);
441 #endif
442 	}
443 
444 out_free:
445 	kfree(iph_base);
446 out:
447 	return err;
448 }
449 
450 static void ah6_input_done(struct crypto_async_request *base, int err)
451 {
452 	u8 *auth_data;
453 	u8 *icv;
454 	u8 *work_iph;
455 	struct sk_buff *skb = base->data;
456 	struct xfrm_state *x = xfrm_input_state(skb);
457 	struct ah_data *ahp = x->data;
458 	struct ip_auth_hdr *ah = ip_auth_hdr(skb);
459 	int hdr_len = skb_network_header_len(skb);
460 	int ah_hlen = (ah->hdrlen + 2) << 2;
461 
462 	work_iph = AH_SKB_CB(skb)->tmp;
463 	auth_data = ah_tmp_auth(work_iph, hdr_len);
464 	icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
465 
466 	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
467 	if (err)
468 		goto out;
469 
470 	err = ah->nexthdr;
471 
472 	skb->network_header += ah_hlen;
473 	memcpy(skb_network_header(skb), work_iph, hdr_len);
474 	__skb_pull(skb, ah_hlen + hdr_len);
475 	skb_set_transport_header(skb, -hdr_len);
476 out:
477 	kfree(AH_SKB_CB(skb)->tmp);
478 	xfrm_input_resume(skb, err);
479 }
480 
481 
482 
483 static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
484 {
485 	/*
486 	 * Before process AH
487 	 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
488 	 * |<-------------->| hdr_len
489 	 *
490 	 * To erase AH:
491 	 * Keeping copy of cleared headers. After AH processing,
492 	 * Moving the pointer of skb->network_header by using skb_pull as long
493 	 * as AH header length. Then copy back the copy as long as hdr_len
494 	 * If destination header following AH exists, copy it into after [Ext2].
495 	 *
496 	 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
497 	 * There is offset of AH before IPv6 header after the process.
498 	 */
499 
500 	u8 *auth_data;
501 	u8 *icv;
502 	u8 *work_iph;
503 	struct sk_buff *trailer;
504 	struct crypto_ahash *ahash;
505 	struct ahash_request *req;
506 	struct scatterlist *sg;
507 	struct ip_auth_hdr *ah;
508 	struct ipv6hdr *ip6h;
509 	struct ah_data *ahp;
510 	u16 hdr_len;
511 	u16 ah_hlen;
512 	int nexthdr;
513 	int nfrags;
514 	int err = -ENOMEM;
515 
516 	if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
517 		goto out;
518 
519 	/* We are going to _remove_ AH header to keep sockets happy,
520 	 * so... Later this can change. */
521 	if (skb_cloned(skb) &&
522 	    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
523 		goto out;
524 
525 	skb->ip_summed = CHECKSUM_NONE;
526 
527 	hdr_len = skb_network_header_len(skb);
528 	ah = (struct ip_auth_hdr *)skb->data;
529 	ahp = x->data;
530 	ahash = ahp->ahash;
531 
532 	nexthdr = ah->nexthdr;
533 	ah_hlen = (ah->hdrlen + 2) << 2;
534 
535 	if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
536 	    ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
537 		goto out;
538 
539 	if (!pskb_may_pull(skb, ah_hlen))
540 		goto out;
541 
542 
543 	if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
544 		goto out;
545 	nfrags = err;
546 
547 	ah = (struct ip_auth_hdr *)skb->data;
548 	ip6h = ipv6_hdr(skb);
549 
550 	skb_push(skb, hdr_len);
551 
552 	work_iph = ah_alloc_tmp(ahash, nfrags, hdr_len + ahp->icv_trunc_len);
553 	if (!work_iph)
554 		goto out;
555 
556 	auth_data = ah_tmp_auth(work_iph, hdr_len);
557 	icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
558 	req = ah_tmp_req(ahash, icv);
559 	sg = ah_req_sg(ahash, req);
560 
561 	memcpy(work_iph, ip6h, hdr_len);
562 	memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
563 	memset(ah->auth_data, 0, ahp->icv_trunc_len);
564 
565 	if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
566 		goto out_free;
567 
568 	ip6h->priority    = 0;
569 	ip6h->flow_lbl[0] = 0;
570 	ip6h->flow_lbl[1] = 0;
571 	ip6h->flow_lbl[2] = 0;
572 	ip6h->hop_limit   = 0;
573 
574 	sg_init_table(sg, nfrags);
575 	skb_to_sgvec(skb, sg, 0, skb->len);
576 
577 	ahash_request_set_crypt(req, sg, icv, skb->len);
578 	ahash_request_set_callback(req, 0, ah6_input_done, skb);
579 
580 	AH_SKB_CB(skb)->tmp = work_iph;
581 
582 	err = crypto_ahash_digest(req);
583 	if (err) {
584 		if (err == -EINPROGRESS)
585 			goto out;
586 
587 		goto out_free;
588 	}
589 
590 	err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
591 	if (err)
592 		goto out_free;
593 
594 	skb->network_header += ah_hlen;
595 	memcpy(skb_network_header(skb), work_iph, hdr_len);
596 	skb->transport_header = skb->network_header;
597 	__skb_pull(skb, ah_hlen + hdr_len);
598 
599 	err = nexthdr;
600 
601 out_free:
602 	kfree(work_iph);
603 out:
604 	return err;
605 }
606 
607 static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
608 		    u8 type, u8 code, int offset, __be32 info)
609 {
610 	struct net *net = dev_net(skb->dev);
611 	struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
612 	struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+offset);
613 	struct xfrm_state *x;
614 
615 	if (type != ICMPV6_DEST_UNREACH &&
616 	    type != ICMPV6_PKT_TOOBIG &&
617 	    type != NDISC_REDIRECT)
618 		return;
619 
620 	x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
621 	if (!x)
622 		return;
623 
624 	if (type == NDISC_REDIRECT)
625 		ip6_redirect(skb, net, 0, 0);
626 	else
627 		ip6_update_pmtu(skb, net, info, 0, 0);
628 	xfrm_state_put(x);
629 }
630 
631 static int ah6_init_state(struct xfrm_state *x)
632 {
633 	struct ah_data *ahp = NULL;
634 	struct xfrm_algo_desc *aalg_desc;
635 	struct crypto_ahash *ahash;
636 
637 	if (!x->aalg)
638 		goto error;
639 
640 	if (x->encap)
641 		goto error;
642 
643 	ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
644 	if (ahp == NULL)
645 		return -ENOMEM;
646 
647 	ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
648 	if (IS_ERR(ahash))
649 		goto error;
650 
651 	ahp->ahash = ahash;
652 	if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
653 			       (x->aalg->alg_key_len + 7) / 8))
654 		goto error;
655 
656 	/*
657 	 * Lookup the algorithm description maintained by xfrm_algo,
658 	 * verify crypto transform properties, and store information
659 	 * we need for AH processing.  This lookup cannot fail here
660 	 * after a successful crypto_alloc_hash().
661 	 */
662 	aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
663 	BUG_ON(!aalg_desc);
664 
665 	if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
666 	    crypto_ahash_digestsize(ahash)) {
667 		pr_info("AH: %s digestsize %u != %hu\n",
668 			x->aalg->alg_name, crypto_ahash_digestsize(ahash),
669 			aalg_desc->uinfo.auth.icv_fullbits/8);
670 		goto error;
671 	}
672 
673 	ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
674 	ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
675 
676 	BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
677 
678 	x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
679 					  ahp->icv_trunc_len);
680 	switch (x->props.mode) {
681 	case XFRM_MODE_BEET:
682 	case XFRM_MODE_TRANSPORT:
683 		break;
684 	case XFRM_MODE_TUNNEL:
685 		x->props.header_len += sizeof(struct ipv6hdr);
686 		break;
687 	default:
688 		goto error;
689 	}
690 	x->data = ahp;
691 
692 	return 0;
693 
694 error:
695 	if (ahp) {
696 		crypto_free_ahash(ahp->ahash);
697 		kfree(ahp);
698 	}
699 	return -EINVAL;
700 }
701 
702 static void ah6_destroy(struct xfrm_state *x)
703 {
704 	struct ah_data *ahp = x->data;
705 
706 	if (!ahp)
707 		return;
708 
709 	crypto_free_ahash(ahp->ahash);
710 	kfree(ahp);
711 }
712 
713 static const struct xfrm_type ah6_type =
714 {
715 	.description	= "AH6",
716 	.owner		= THIS_MODULE,
717 	.proto	     	= IPPROTO_AH,
718 	.flags		= XFRM_TYPE_REPLAY_PROT,
719 	.init_state	= ah6_init_state,
720 	.destructor	= ah6_destroy,
721 	.input		= ah6_input,
722 	.output		= ah6_output,
723 	.hdr_offset	= xfrm6_find_1stfragopt,
724 };
725 
726 static const struct inet6_protocol ah6_protocol = {
727 	.handler	=	xfrm6_rcv,
728 	.err_handler	=	ah6_err,
729 	.flags		=	INET6_PROTO_NOPOLICY,
730 };
731 
732 static int __init ah6_init(void)
733 {
734 	if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
735 		pr_info("%s: can't add xfrm type\n", __func__);
736 		return -EAGAIN;
737 	}
738 
739 	if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
740 		pr_info("%s: can't add protocol\n", __func__);
741 		xfrm_unregister_type(&ah6_type, AF_INET6);
742 		return -EAGAIN;
743 	}
744 
745 	return 0;
746 }
747 
748 static void __exit ah6_fini(void)
749 {
750 	if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
751 		pr_info("%s: can't remove protocol\n", __func__);
752 
753 	if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
754 		pr_info("%s: can't remove xfrm type\n", __func__);
755 
756 }
757 
758 module_init(ah6_init);
759 module_exit(ah6_fini);
760 
761 MODULE_LICENSE("GPL");
762 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);
763