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