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
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
49 /* Helper to save IPv6 addresses and extension headers to temporary storage */
ah6_save_hdrs(struct tmp_ext * iph_ext,struct ipv6hdr * top_iph,int extlen)50 static inline void ah6_save_hdrs(struct tmp_ext *iph_ext,
51 struct ipv6hdr *top_iph, int extlen)
52 {
53 if (!extlen)
54 return;
55
56 #if IS_ENABLED(CONFIG_IPV6_MIP6)
57 iph_ext->saddr = top_iph->saddr;
58 #endif
59 iph_ext->daddr = top_iph->daddr;
60 memcpy(&iph_ext->hdrs, top_iph + 1, extlen - sizeof(*iph_ext));
61 }
62
63 /* Helper to restore IPv6 addresses and extension headers from temporary storage */
ah6_restore_hdrs(struct ipv6hdr * top_iph,struct tmp_ext * iph_ext,int extlen)64 static inline void ah6_restore_hdrs(struct ipv6hdr *top_iph,
65 struct tmp_ext *iph_ext, int extlen)
66 {
67 if (!extlen)
68 return;
69
70 #if IS_ENABLED(CONFIG_IPV6_MIP6)
71 top_iph->saddr = iph_ext->saddr;
72 #endif
73 top_iph->daddr = iph_ext->daddr;
74 memcpy(top_iph + 1, &iph_ext->hdrs, extlen - sizeof(*iph_ext));
75 }
76
ah_alloc_tmp(struct crypto_ahash * ahash,int nfrags,unsigned int size)77 static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
78 unsigned int size)
79 {
80 unsigned int len;
81
82 len = size + crypto_ahash_digestsize(ahash);
83
84 len = ALIGN(len, crypto_tfm_ctx_alignment());
85
86 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
87 len = ALIGN(len, __alignof__(struct scatterlist));
88
89 len += sizeof(struct scatterlist) * nfrags;
90
91 return kmalloc(len, GFP_ATOMIC);
92 }
93
ah_tmp_ext(void * base)94 static inline struct tmp_ext *ah_tmp_ext(void *base)
95 {
96 return base + IPV6HDR_BASELEN;
97 }
98
ah_tmp_auth(u8 * tmp,unsigned int offset)99 static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
100 {
101 return tmp + offset;
102 }
103
ah_tmp_icv(void * tmp,unsigned int offset)104 static inline u8 *ah_tmp_icv(void *tmp, unsigned int offset)
105 {
106 return tmp + offset;
107 }
108
ah_tmp_req(struct crypto_ahash * ahash,u8 * icv)109 static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
110 u8 *icv)
111 {
112 struct ahash_request *req;
113
114 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
115 crypto_tfm_ctx_alignment());
116
117 ahash_request_set_tfm(req, ahash);
118
119 return req;
120 }
121
ah_req_sg(struct crypto_ahash * ahash,struct ahash_request * req)122 static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
123 struct ahash_request *req)
124 {
125 return (void *)ALIGN((unsigned long)(req + 1) +
126 crypto_ahash_reqsize(ahash),
127 __alignof__(struct scatterlist));
128 }
129
zero_out_mutable_opts(struct ipv6_opt_hdr * opthdr)130 static bool zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
131 {
132 u8 *opt = (u8 *)opthdr;
133 int len = ipv6_optlen(opthdr);
134 int off = 0;
135 int optlen = 0;
136
137 off += 2;
138 len -= 2;
139
140 while (len > 0) {
141
142 switch (opt[off]) {
143
144 case IPV6_TLV_PAD1:
145 optlen = 1;
146 break;
147 default:
148 if (len < 2)
149 goto bad;
150 optlen = opt[off+1]+2;
151 if (len < optlen)
152 goto bad;
153 if (opt[off] & 0x20)
154 memset(&opt[off+2], 0, opt[off+1]);
155 break;
156 }
157
158 off += optlen;
159 len -= optlen;
160 }
161 if (len == 0)
162 return true;
163
164 bad:
165 return false;
166 }
167
168 #if IS_ENABLED(CONFIG_IPV6_MIP6)
169 /**
170 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
171 * @iph: IPv6 header
172 * @destopt: destionation options header
173 */
ipv6_rearrange_destopt(struct ipv6hdr * iph,struct ipv6_opt_hdr * destopt)174 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
175 {
176 u8 *opt = (u8 *)destopt;
177 int len = ipv6_optlen(destopt);
178 int off = 0;
179 int optlen = 0;
180
181 off += 2;
182 len -= 2;
183
184 while (len > 0) {
185
186 switch (opt[off]) {
187
188 case IPV6_TLV_PAD1:
189 optlen = 1;
190 break;
191 default:
192 if (len < 2)
193 goto bad;
194 optlen = opt[off+1]+2;
195 if (len < optlen)
196 goto bad;
197
198 /* Rearrange the source address in @iph and the
199 * addresses in home address option for final source.
200 * See 11.3.2 of RFC 3775 for details.
201 */
202 if (opt[off] == IPV6_TLV_HAO) {
203 struct ipv6_destopt_hao *hao;
204
205 hao = (struct ipv6_destopt_hao *)&opt[off];
206 if (hao->length != sizeof(hao->addr)) {
207 net_warn_ratelimited("destopt hao: invalid header length: %u\n",
208 hao->length);
209 goto bad;
210 }
211 swap(hao->addr, iph->saddr);
212 }
213 break;
214 }
215
216 off += optlen;
217 len -= optlen;
218 }
219 /* Note: ok if len == 0 */
220 bad:
221 return;
222 }
223 #else
ipv6_rearrange_destopt(struct ipv6hdr * iph,struct ipv6_opt_hdr * destopt)224 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
225 #endif
226
227 /**
228 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
229 * @iph: IPv6 header
230 * @rthdr: routing header
231 *
232 * Rearrange the destination address in @iph and the addresses in @rthdr
233 * so that they appear in the order they will at the final destination.
234 * See Appendix A2 of RFC 2402 for details.
235 *
236 * Return: 0 on success, -EINVAL if segments_left exceeds the number of
237 * addresses described by hdrlen.
238 */
ipv6_rearrange_rthdr(struct ipv6hdr * iph,struct ipv6_rt_hdr * rthdr)239 static int ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
240 {
241 unsigned int segments, segments_left;
242 struct in6_addr *addrs;
243 struct in6_addr final_addr;
244
245 segments_left = rthdr->segments_left;
246 if (segments_left == 0)
247 return 0;
248
249 /* Raw locally generated packets can reach AH6 without the invariant
250 * required by the rt0-style address rearrangement below.
251 */
252 segments = rthdr->hdrlen >> 1;
253 if (segments_left > segments)
254 return -EINVAL;
255
256 rthdr->segments_left = 0;
257
258 addrs = ((struct rt0_hdr *)rthdr)->addr;
259 final_addr = addrs[segments - 1];
260
261 addrs += segments - segments_left;
262 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
263
264 addrs[0] = iph->daddr;
265 iph->daddr = final_addr;
266
267 return 0;
268 }
269
ipv6_clear_mutable_options(struct ipv6hdr * iph,int len,int dir)270 static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
271 {
272 union {
273 struct ipv6hdr *iph;
274 struct ipv6_opt_hdr *opth;
275 struct ipv6_rt_hdr *rth;
276 char *raw;
277 } exthdr = { .iph = iph };
278 char *end = exthdr.raw + len;
279 int nexthdr = iph->nexthdr;
280 int err;
281
282 exthdr.iph++;
283
284 while (exthdr.raw < end) {
285 switch (nexthdr) {
286 case NEXTHDR_DEST:
287 if (dir == XFRM_POLICY_OUT)
288 ipv6_rearrange_destopt(iph, exthdr.opth);
289 fallthrough;
290 case NEXTHDR_HOP:
291 if (!zero_out_mutable_opts(exthdr.opth)) {
292 net_dbg_ratelimited("overrun %sopts\n",
293 nexthdr == NEXTHDR_HOP ?
294 "hop" : "dest");
295 return -EINVAL;
296 }
297 break;
298
299 case NEXTHDR_ROUTING:
300 err = ipv6_rearrange_rthdr(iph, exthdr.rth);
301 if (err)
302 return err;
303 break;
304
305 default:
306 return 0;
307 }
308
309 nexthdr = exthdr.opth->nexthdr;
310 exthdr.raw += ipv6_optlen(exthdr.opth);
311 }
312
313 return 0;
314 }
315
ah6_output_done(void * data,int err)316 static void ah6_output_done(void *data, int err)
317 {
318 int extlen;
319 u8 *iph_base;
320 u8 *icv;
321 struct sk_buff *skb = data;
322 struct xfrm_state *x = skb_dst(skb)->xfrm;
323 struct ah_data *ahp = x->data;
324 struct ipv6hdr *top_iph = ipv6_hdr(skb);
325 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
326 struct tmp_ext *iph_ext;
327 int seqhi_len = 0;
328 __be32 *seqhi;
329
330 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
331 if (extlen)
332 extlen += sizeof(*iph_ext);
333
334 if (x->props.flags & XFRM_STATE_ESN)
335 seqhi_len = sizeof(*seqhi);
336 iph_base = AH_SKB_CB(skb)->tmp;
337 iph_ext = ah_tmp_ext(iph_base);
338 seqhi = (__be32 *)((char *)iph_ext + extlen);
339 icv = ah_tmp_icv(seqhi, seqhi_len);
340
341 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
342 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
343
344 ah6_restore_hdrs(top_iph, iph_ext, extlen);
345
346 kfree(AH_SKB_CB(skb)->tmp);
347 xfrm_output_resume(skb_to_full_sk(skb), skb, err);
348 }
349
ah6_output(struct xfrm_state * x,struct sk_buff * skb)350 static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
351 {
352 int err;
353 int nfrags;
354 int extlen;
355 u8 *iph_base;
356 u8 *icv;
357 u8 nexthdr;
358 struct sk_buff *trailer;
359 struct crypto_ahash *ahash;
360 struct ahash_request *req;
361 struct scatterlist *sg;
362 struct ipv6hdr *top_iph;
363 struct ip_auth_hdr *ah;
364 struct ah_data *ahp;
365 struct tmp_ext *iph_ext;
366 int seqhi_len = 0;
367 __be32 *seqhi;
368 int sglists = 0;
369 struct scatterlist *seqhisg;
370
371 ahp = x->data;
372 ahash = ahp->ahash;
373
374 err = skb_cow_data(skb, 0, &trailer);
375 if (err < 0)
376 goto out;
377 nfrags = err;
378
379 skb_push(skb, -skb_network_offset(skb));
380 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
381 if (extlen)
382 extlen += sizeof(*iph_ext);
383
384 if (x->props.flags & XFRM_STATE_ESN) {
385 sglists = 1;
386 seqhi_len = sizeof(*seqhi);
387 }
388 err = -ENOMEM;
389 iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN +
390 extlen + seqhi_len);
391 if (!iph_base)
392 goto out;
393
394 iph_ext = ah_tmp_ext(iph_base);
395 seqhi = (__be32 *)((char *)iph_ext + extlen);
396 icv = ah_tmp_icv(seqhi, seqhi_len);
397 req = ah_tmp_req(ahash, icv);
398 sg = ah_req_sg(ahash, req);
399 seqhisg = sg + nfrags;
400
401 ah = ip_auth_hdr(skb);
402 memset(ah->auth_data, 0, ahp->icv_trunc_len);
403
404 top_iph = ipv6_hdr(skb);
405 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
406
407 nexthdr = *skb_mac_header(skb);
408 *skb_mac_header(skb) = IPPROTO_AH;
409
410 /* When there are no extension headers, we only need to save the first
411 * 8 bytes of the base IP header.
412 */
413 memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
414
415 ah6_save_hdrs(iph_ext, top_iph, extlen);
416 if (extlen) {
417 err = ipv6_clear_mutable_options(top_iph,
418 extlen - sizeof(*iph_ext) +
419 sizeof(*top_iph),
420 XFRM_POLICY_OUT);
421 if (err)
422 goto out_free;
423 }
424
425 ah->nexthdr = nexthdr;
426
427 top_iph->priority = 0;
428 top_iph->flow_lbl[0] = 0;
429 top_iph->flow_lbl[1] = 0;
430 top_iph->flow_lbl[2] = 0;
431 top_iph->hop_limit = 0;
432
433 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
434
435 ah->reserved = 0;
436 ah->spi = x->id.spi;
437 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
438
439 sg_init_table(sg, nfrags + sglists);
440 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
441 if (unlikely(err < 0))
442 goto out_free;
443
444 if (x->props.flags & XFRM_STATE_ESN) {
445 /* Attach seqhi sg right after packet payload */
446 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
447 sg_set_buf(seqhisg, seqhi, seqhi_len);
448 }
449 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
450 ahash_request_set_callback(req, 0, ah6_output_done, skb);
451
452 AH_SKB_CB(skb)->tmp = iph_base;
453
454 err = crypto_ahash_digest(req);
455 if (err) {
456 if (err == -EINPROGRESS)
457 goto out;
458
459 if (err == -ENOSPC)
460 err = NET_XMIT_DROP;
461 goto out_free;
462 }
463
464 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
465 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
466
467 ah6_restore_hdrs(top_iph, iph_ext, extlen);
468
469 out_free:
470 kfree(iph_base);
471 out:
472 return err;
473 }
474
ah6_input_done(void * data,int err)475 static void ah6_input_done(void *data, int err)
476 {
477 u8 *auth_data;
478 u8 *icv;
479 u8 *work_iph;
480 struct sk_buff *skb = data;
481 struct xfrm_state *x = xfrm_input_state(skb);
482 struct ah_data *ahp = x->data;
483 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
484 int hdr_len = skb_network_header_len(skb);
485 int ah_hlen = ipv6_authlen(ah);
486 int seqhi_len = 0;
487 __be32 *seqhi;
488
489 if (err)
490 goto out;
491
492 if (x->props.flags & XFRM_STATE_ESN)
493 seqhi_len = sizeof(*seqhi);
494 work_iph = AH_SKB_CB(skb)->tmp;
495 auth_data = ah_tmp_auth(work_iph, hdr_len);
496 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len);
497 icv = ah_tmp_icv(seqhi, seqhi_len);
498
499 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
500 if (err)
501 goto out;
502
503 err = ah->nexthdr;
504
505 skb->network_header += ah_hlen;
506 memcpy(skb_network_header(skb), work_iph, hdr_len);
507 __skb_pull(skb, ah_hlen + hdr_len);
508 if (x->props.mode == XFRM_MODE_TUNNEL)
509 skb_reset_transport_header(skb);
510 else
511 skb_set_transport_header(skb, -hdr_len);
512 out:
513 kfree(AH_SKB_CB(skb)->tmp);
514 xfrm_input_resume(skb, err);
515 }
516
517
518
ah6_input(struct xfrm_state * x,struct sk_buff * skb)519 static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
520 {
521 /*
522 * Before process AH
523 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
524 * |<-------------->| hdr_len
525 *
526 * To erase AH:
527 * Keeping copy of cleared headers. After AH processing,
528 * Moving the pointer of skb->network_header by using skb_pull as long
529 * as AH header length. Then copy back the copy as long as hdr_len
530 * If destination header following AH exists, copy it into after [Ext2].
531 *
532 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
533 * There is offset of AH before IPv6 header after the process.
534 */
535
536 u8 *auth_data;
537 u8 *icv;
538 u8 *work_iph;
539 struct sk_buff *trailer;
540 struct crypto_ahash *ahash;
541 struct ahash_request *req;
542 struct scatterlist *sg;
543 struct ip_auth_hdr *ah;
544 struct ipv6hdr *ip6h;
545 struct ah_data *ahp;
546 u16 hdr_len;
547 u16 ah_hlen;
548 int nexthdr;
549 int nfrags;
550 int err = -ENOMEM;
551 int seqhi_len = 0;
552 __be32 *seqhi;
553 int sglists = 0;
554 struct scatterlist *seqhisg;
555
556 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
557 goto out;
558
559 /* We are going to _remove_ AH header to keep sockets happy,
560 * so... Later this can change. */
561 if (skb_unclone(skb, GFP_ATOMIC))
562 goto out;
563
564 skb->ip_summed = CHECKSUM_NONE;
565
566 hdr_len = skb_network_header_len(skb);
567 ah = (struct ip_auth_hdr *)skb->data;
568 ahp = x->data;
569 ahash = ahp->ahash;
570
571 nexthdr = ah->nexthdr;
572 ah_hlen = ipv6_authlen(ah);
573
574 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
575 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
576 goto out;
577
578 if (!pskb_may_pull(skb, ah_hlen))
579 goto out;
580
581 err = skb_cow_data(skb, 0, &trailer);
582 if (err < 0)
583 goto out;
584 nfrags = err;
585
586 ah = (struct ip_auth_hdr *)skb->data;
587 ip6h = ipv6_hdr(skb);
588
589 skb_push(skb, hdr_len);
590
591 if (x->props.flags & XFRM_STATE_ESN) {
592 sglists = 1;
593 seqhi_len = sizeof(*seqhi);
594 }
595
596 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len +
597 ahp->icv_trunc_len + seqhi_len);
598 if (!work_iph) {
599 err = -ENOMEM;
600 goto out;
601 }
602
603 auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len);
604 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len);
605 icv = ah_tmp_icv(seqhi, seqhi_len);
606 req = ah_tmp_req(ahash, icv);
607 sg = ah_req_sg(ahash, req);
608 seqhisg = sg + nfrags;
609
610 memcpy(work_iph, ip6h, hdr_len);
611 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
612 memset(ah->auth_data, 0, ahp->icv_trunc_len);
613
614 err = ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN);
615 if (err)
616 goto out_free;
617
618 ip6h->priority = 0;
619 ip6h->flow_lbl[0] = 0;
620 ip6h->flow_lbl[1] = 0;
621 ip6h->flow_lbl[2] = 0;
622 ip6h->hop_limit = 0;
623
624 sg_init_table(sg, nfrags + sglists);
625 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
626 if (unlikely(err < 0))
627 goto out_free;
628
629 if (x->props.flags & XFRM_STATE_ESN) {
630 /* Attach seqhi sg right after packet payload */
631 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
632 sg_set_buf(seqhisg, seqhi, seqhi_len);
633 }
634
635 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
636 ahash_request_set_callback(req, 0, ah6_input_done, skb);
637
638 AH_SKB_CB(skb)->tmp = work_iph;
639
640 err = crypto_ahash_digest(req);
641 if (err) {
642 if (err == -EINPROGRESS)
643 goto out;
644
645 goto out_free;
646 }
647
648 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
649 if (err)
650 goto out_free;
651
652 skb->network_header += ah_hlen;
653 memcpy(skb_network_header(skb), work_iph, hdr_len);
654 __skb_pull(skb, ah_hlen + hdr_len);
655
656 if (x->props.mode == XFRM_MODE_TUNNEL)
657 skb_reset_transport_header(skb);
658 else
659 skb_set_transport_header(skb, -hdr_len);
660
661 err = nexthdr;
662
663 out_free:
664 kfree(work_iph);
665 out:
666 return err;
667 }
668
ah6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)669 static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
670 u8 type, u8 code, int offset, __be32 info)
671 {
672 struct net *net = dev_net(skb->dev);
673 struct ipv6hdr *iph = (struct ipv6hdr *)skb->data;
674 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+offset);
675 struct xfrm_state *x;
676
677 if (type != ICMPV6_PKT_TOOBIG &&
678 type != NDISC_REDIRECT)
679 return 0;
680
681 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
682 if (!x)
683 return 0;
684
685 if (type == NDISC_REDIRECT)
686 ip6_redirect(skb, net, skb->dev->ifindex, 0,
687 sock_net_uid(net, NULL));
688 else
689 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
690 xfrm_state_put(x);
691
692 return 0;
693 }
694
ah6_init_state(struct xfrm_state * x,struct netlink_ext_ack * extack)695 static int ah6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
696 {
697 struct ah_data *ahp = NULL;
698 struct xfrm_algo_desc *aalg_desc;
699 struct crypto_ahash *ahash;
700
701 if (!x->aalg) {
702 NL_SET_ERR_MSG(extack, "AH requires a state with an AUTH algorithm");
703 goto error;
704 }
705
706 if (x->encap) {
707 NL_SET_ERR_MSG(extack, "AH is not compatible with encapsulation");
708 goto error;
709 }
710
711 ahp = kzalloc_obj(*ahp);
712 if (!ahp)
713 return -ENOMEM;
714
715 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
716 if (IS_ERR(ahash)) {
717 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
718 goto error;
719 }
720
721 ahp->ahash = ahash;
722 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
723 (x->aalg->alg_key_len + 7) / 8)) {
724 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
725 goto error;
726 }
727
728 /*
729 * Lookup the algorithm description maintained by xfrm_algo,
730 * verify crypto transform properties, and store information
731 * we need for AH processing. This lookup cannot fail here
732 * after a successful crypto_alloc_hash().
733 */
734 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
735 BUG_ON(!aalg_desc);
736
737 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
738 crypto_ahash_digestsize(ahash)) {
739 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
740 goto error;
741 }
742
743 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
744 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
745
746 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
747 ahp->icv_trunc_len);
748 switch (x->props.mode) {
749 case XFRM_MODE_BEET:
750 case XFRM_MODE_TRANSPORT:
751 break;
752 case XFRM_MODE_TUNNEL:
753 x->props.header_len += sizeof(struct ipv6hdr);
754 break;
755 default:
756 NL_SET_ERR_MSG(extack, "Invalid mode requested for AH, must be one of TRANSPORT, TUNNEL, BEET");
757 goto error;
758 }
759 x->data = ahp;
760
761 return 0;
762
763 error:
764 if (ahp) {
765 crypto_free_ahash(ahp->ahash);
766 kfree(ahp);
767 }
768 return -EINVAL;
769 }
770
ah6_destroy(struct xfrm_state * x)771 static void ah6_destroy(struct xfrm_state *x)
772 {
773 struct ah_data *ahp = x->data;
774
775 if (!ahp)
776 return;
777
778 crypto_free_ahash(ahp->ahash);
779 kfree(ahp);
780 }
781
ah6_rcv_cb(struct sk_buff * skb,int err)782 static int ah6_rcv_cb(struct sk_buff *skb, int err)
783 {
784 return 0;
785 }
786
787 static const struct xfrm_type ah6_type = {
788 .owner = THIS_MODULE,
789 .proto = IPPROTO_AH,
790 .flags = XFRM_TYPE_REPLAY_PROT,
791 .init_state = ah6_init_state,
792 .destructor = ah6_destroy,
793 .input = ah6_input,
794 .output = ah6_output,
795 };
796
797 static struct xfrm6_protocol ah6_protocol = {
798 .handler = xfrm6_rcv,
799 .input_handler = xfrm_input,
800 .cb_handler = ah6_rcv_cb,
801 .err_handler = ah6_err,
802 .priority = 0,
803 };
804
ah6_init(void)805 static int __init ah6_init(void)
806 {
807 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
808 pr_info("%s: can't add xfrm type\n", __func__);
809 return -EAGAIN;
810 }
811
812 if (xfrm6_protocol_register(&ah6_protocol, IPPROTO_AH) < 0) {
813 pr_info("%s: can't add protocol\n", __func__);
814 xfrm_unregister_type(&ah6_type, AF_INET6);
815 return -EAGAIN;
816 }
817
818 return 0;
819 }
820
ah6_fini(void)821 static void __exit ah6_fini(void)
822 {
823 if (xfrm6_protocol_deregister(&ah6_protocol, IPPROTO_AH) < 0)
824 pr_info("%s: can't remove protocol\n", __func__);
825
826 xfrm_unregister_type(&ah6_type, AF_INET6);
827 }
828
829 module_init(ah6_init);
830 module_exit(ah6_fini);
831
832 MODULE_DESCRIPTION("IPv6 AH transformation helpers");
833 MODULE_LICENSE("GPL");
834 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);
835