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 */
ipv6_rearrange_rthdr(struct ipv6hdr * iph,struct ipv6_rt_hdr * rthdr)236 static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
237 {
238 int segments, segments_left;
239 struct in6_addr *addrs;
240 struct in6_addr final_addr;
241
242 segments_left = rthdr->segments_left;
243 if (segments_left == 0)
244 return;
245 rthdr->segments_left = 0;
246
247 /* The value of rthdr->hdrlen has been verified either by the system
248 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
249 * packets. So we can assume that it is even and that segments is
250 * greater than or equal to segments_left.
251 *
252 * For the same reason we can assume that this option is of type 0.
253 */
254 segments = rthdr->hdrlen >> 1;
255
256 addrs = ((struct rt0_hdr *)rthdr)->addr;
257 final_addr = addrs[segments - 1];
258
259 addrs += segments - segments_left;
260 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
261
262 addrs[0] = iph->daddr;
263 iph->daddr = final_addr;
264 }
265
ipv6_clear_mutable_options(struct ipv6hdr * iph,int len,int dir)266 static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
267 {
268 union {
269 struct ipv6hdr *iph;
270 struct ipv6_opt_hdr *opth;
271 struct ipv6_rt_hdr *rth;
272 char *raw;
273 } exthdr = { .iph = iph };
274 char *end = exthdr.raw + len;
275 int nexthdr = iph->nexthdr;
276
277 exthdr.iph++;
278
279 while (exthdr.raw < end) {
280 switch (nexthdr) {
281 case NEXTHDR_DEST:
282 if (dir == XFRM_POLICY_OUT)
283 ipv6_rearrange_destopt(iph, exthdr.opth);
284 fallthrough;
285 case NEXTHDR_HOP:
286 if (!zero_out_mutable_opts(exthdr.opth)) {
287 net_dbg_ratelimited("overrun %sopts\n",
288 nexthdr == NEXTHDR_HOP ?
289 "hop" : "dest");
290 return -EINVAL;
291 }
292 break;
293
294 case NEXTHDR_ROUTING:
295 ipv6_rearrange_rthdr(iph, exthdr.rth);
296 break;
297
298 default:
299 return 0;
300 }
301
302 nexthdr = exthdr.opth->nexthdr;
303 exthdr.raw += ipv6_optlen(exthdr.opth);
304 }
305
306 return 0;
307 }
308
ah6_output_done(void * data,int err)309 static void ah6_output_done(void *data, int err)
310 {
311 int extlen;
312 u8 *iph_base;
313 u8 *icv;
314 struct sk_buff *skb = data;
315 struct xfrm_state *x = skb_dst(skb)->xfrm;
316 struct ah_data *ahp = x->data;
317 struct ipv6hdr *top_iph = ipv6_hdr(skb);
318 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
319 struct tmp_ext *iph_ext;
320 int seqhi_len = 0;
321 __be32 *seqhi;
322
323 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
324 if (extlen)
325 extlen += sizeof(*iph_ext);
326
327 if (x->props.flags & XFRM_STATE_ESN)
328 seqhi_len = sizeof(*seqhi);
329 iph_base = AH_SKB_CB(skb)->tmp;
330 iph_ext = ah_tmp_ext(iph_base);
331 seqhi = (__be32 *)((char *)iph_ext + extlen);
332 icv = ah_tmp_icv(seqhi, seqhi_len);
333
334 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
335 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
336
337 ah6_restore_hdrs(top_iph, iph_ext, extlen);
338
339 kfree(AH_SKB_CB(skb)->tmp);
340 xfrm_output_resume(skb->sk, skb, err);
341 }
342
ah6_output(struct xfrm_state * x,struct sk_buff * skb)343 static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
344 {
345 int err;
346 int nfrags;
347 int extlen;
348 u8 *iph_base;
349 u8 *icv;
350 u8 nexthdr;
351 struct sk_buff *trailer;
352 struct crypto_ahash *ahash;
353 struct ahash_request *req;
354 struct scatterlist *sg;
355 struct ipv6hdr *top_iph;
356 struct ip_auth_hdr *ah;
357 struct ah_data *ahp;
358 struct tmp_ext *iph_ext;
359 int seqhi_len = 0;
360 __be32 *seqhi;
361 int sglists = 0;
362 struct scatterlist *seqhisg;
363
364 ahp = x->data;
365 ahash = ahp->ahash;
366
367 err = skb_cow_data(skb, 0, &trailer);
368 if (err < 0)
369 goto out;
370 nfrags = err;
371
372 skb_push(skb, -skb_network_offset(skb));
373 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
374 if (extlen)
375 extlen += sizeof(*iph_ext);
376
377 if (x->props.flags & XFRM_STATE_ESN) {
378 sglists = 1;
379 seqhi_len = sizeof(*seqhi);
380 }
381 err = -ENOMEM;
382 iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN +
383 extlen + seqhi_len);
384 if (!iph_base)
385 goto out;
386
387 iph_ext = ah_tmp_ext(iph_base);
388 seqhi = (__be32 *)((char *)iph_ext + extlen);
389 icv = ah_tmp_icv(seqhi, seqhi_len);
390 req = ah_tmp_req(ahash, icv);
391 sg = ah_req_sg(ahash, req);
392 seqhisg = sg + nfrags;
393
394 ah = ip_auth_hdr(skb);
395 memset(ah->auth_data, 0, ahp->icv_trunc_len);
396
397 top_iph = ipv6_hdr(skb);
398 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
399
400 nexthdr = *skb_mac_header(skb);
401 *skb_mac_header(skb) = IPPROTO_AH;
402
403 /* When there are no extension headers, we only need to save the first
404 * 8 bytes of the base IP header.
405 */
406 memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
407
408 ah6_save_hdrs(iph_ext, top_iph, extlen);
409 if (extlen) {
410 err = ipv6_clear_mutable_options(top_iph,
411 extlen - sizeof(*iph_ext) +
412 sizeof(*top_iph),
413 XFRM_POLICY_OUT);
414 if (err)
415 goto out_free;
416 }
417
418 ah->nexthdr = nexthdr;
419
420 top_iph->priority = 0;
421 top_iph->flow_lbl[0] = 0;
422 top_iph->flow_lbl[1] = 0;
423 top_iph->flow_lbl[2] = 0;
424 top_iph->hop_limit = 0;
425
426 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
427
428 ah->reserved = 0;
429 ah->spi = x->id.spi;
430 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
431
432 sg_init_table(sg, nfrags + sglists);
433 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
434 if (unlikely(err < 0))
435 goto out_free;
436
437 if (x->props.flags & XFRM_STATE_ESN) {
438 /* Attach seqhi sg right after packet payload */
439 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
440 sg_set_buf(seqhisg, seqhi, seqhi_len);
441 }
442 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
443 ahash_request_set_callback(req, 0, ah6_output_done, skb);
444
445 AH_SKB_CB(skb)->tmp = iph_base;
446
447 err = crypto_ahash_digest(req);
448 if (err) {
449 if (err == -EINPROGRESS)
450 goto out;
451
452 if (err == -ENOSPC)
453 err = NET_XMIT_DROP;
454 goto out_free;
455 }
456
457 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
458 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
459
460 ah6_restore_hdrs(top_iph, iph_ext, extlen);
461
462 out_free:
463 kfree(iph_base);
464 out:
465 return err;
466 }
467
ah6_input_done(void * data,int err)468 static void ah6_input_done(void *data, int err)
469 {
470 u8 *auth_data;
471 u8 *icv;
472 u8 *work_iph;
473 struct sk_buff *skb = data;
474 struct xfrm_state *x = xfrm_input_state(skb);
475 struct ah_data *ahp = x->data;
476 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
477 int hdr_len = skb_network_header_len(skb);
478 int ah_hlen = ipv6_authlen(ah);
479 int seqhi_len = 0;
480 __be32 *seqhi;
481
482 if (err)
483 goto out;
484
485 if (x->props.flags & XFRM_STATE_ESN)
486 seqhi_len = sizeof(*seqhi);
487 work_iph = AH_SKB_CB(skb)->tmp;
488 auth_data = ah_tmp_auth(work_iph, hdr_len);
489 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len);
490 icv = ah_tmp_icv(seqhi, seqhi_len);
491
492 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
493 if (err)
494 goto out;
495
496 err = ah->nexthdr;
497
498 skb->network_header += ah_hlen;
499 memcpy(skb_network_header(skb), work_iph, hdr_len);
500 __skb_pull(skb, ah_hlen + hdr_len);
501 if (x->props.mode == XFRM_MODE_TUNNEL)
502 skb_reset_transport_header(skb);
503 else
504 skb_set_transport_header(skb, -hdr_len);
505 out:
506 kfree(AH_SKB_CB(skb)->tmp);
507 xfrm_input_resume(skb, err);
508 }
509
510
511
ah6_input(struct xfrm_state * x,struct sk_buff * skb)512 static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
513 {
514 /*
515 * Before process AH
516 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
517 * |<-------------->| hdr_len
518 *
519 * To erase AH:
520 * Keeping copy of cleared headers. After AH processing,
521 * Moving the pointer of skb->network_header by using skb_pull as long
522 * as AH header length. Then copy back the copy as long as hdr_len
523 * If destination header following AH exists, copy it into after [Ext2].
524 *
525 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
526 * There is offset of AH before IPv6 header after the process.
527 */
528
529 u8 *auth_data;
530 u8 *icv;
531 u8 *work_iph;
532 struct sk_buff *trailer;
533 struct crypto_ahash *ahash;
534 struct ahash_request *req;
535 struct scatterlist *sg;
536 struct ip_auth_hdr *ah;
537 struct ipv6hdr *ip6h;
538 struct ah_data *ahp;
539 u16 hdr_len;
540 u16 ah_hlen;
541 int nexthdr;
542 int nfrags;
543 int err = -ENOMEM;
544 int seqhi_len = 0;
545 __be32 *seqhi;
546 int sglists = 0;
547 struct scatterlist *seqhisg;
548
549 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
550 goto out;
551
552 /* We are going to _remove_ AH header to keep sockets happy,
553 * so... Later this can change. */
554 if (skb_unclone(skb, GFP_ATOMIC))
555 goto out;
556
557 skb->ip_summed = CHECKSUM_NONE;
558
559 hdr_len = skb_network_header_len(skb);
560 ah = (struct ip_auth_hdr *)skb->data;
561 ahp = x->data;
562 ahash = ahp->ahash;
563
564 nexthdr = ah->nexthdr;
565 ah_hlen = ipv6_authlen(ah);
566
567 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
568 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
569 goto out;
570
571 if (!pskb_may_pull(skb, ah_hlen))
572 goto out;
573
574 err = skb_cow_data(skb, 0, &trailer);
575 if (err < 0)
576 goto out;
577 nfrags = err;
578
579 ah = (struct ip_auth_hdr *)skb->data;
580 ip6h = ipv6_hdr(skb);
581
582 skb_push(skb, hdr_len);
583
584 if (x->props.flags & XFRM_STATE_ESN) {
585 sglists = 1;
586 seqhi_len = sizeof(*seqhi);
587 }
588
589 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len +
590 ahp->icv_trunc_len + seqhi_len);
591 if (!work_iph) {
592 err = -ENOMEM;
593 goto out;
594 }
595
596 auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len);
597 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len);
598 icv = ah_tmp_icv(seqhi, seqhi_len);
599 req = ah_tmp_req(ahash, icv);
600 sg = ah_req_sg(ahash, req);
601 seqhisg = sg + nfrags;
602
603 memcpy(work_iph, ip6h, hdr_len);
604 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
605 memset(ah->auth_data, 0, ahp->icv_trunc_len);
606
607 err = ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN);
608 if (err)
609 goto out_free;
610
611 ip6h->priority = 0;
612 ip6h->flow_lbl[0] = 0;
613 ip6h->flow_lbl[1] = 0;
614 ip6h->flow_lbl[2] = 0;
615 ip6h->hop_limit = 0;
616
617 sg_init_table(sg, nfrags + sglists);
618 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
619 if (unlikely(err < 0))
620 goto out_free;
621
622 if (x->props.flags & XFRM_STATE_ESN) {
623 /* Attach seqhi sg right after packet payload */
624 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
625 sg_set_buf(seqhisg, seqhi, seqhi_len);
626 }
627
628 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
629 ahash_request_set_callback(req, 0, ah6_input_done, skb);
630
631 AH_SKB_CB(skb)->tmp = work_iph;
632
633 err = crypto_ahash_digest(req);
634 if (err) {
635 if (err == -EINPROGRESS)
636 goto out;
637
638 goto out_free;
639 }
640
641 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
642 if (err)
643 goto out_free;
644
645 skb->network_header += ah_hlen;
646 memcpy(skb_network_header(skb), work_iph, hdr_len);
647 __skb_pull(skb, ah_hlen + hdr_len);
648
649 if (x->props.mode == XFRM_MODE_TUNNEL)
650 skb_reset_transport_header(skb);
651 else
652 skb_set_transport_header(skb, -hdr_len);
653
654 err = nexthdr;
655
656 out_free:
657 kfree(work_iph);
658 out:
659 return err;
660 }
661
ah6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)662 static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
663 u8 type, u8 code, int offset, __be32 info)
664 {
665 struct net *net = dev_net(skb->dev);
666 struct ipv6hdr *iph = (struct ipv6hdr *)skb->data;
667 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+offset);
668 struct xfrm_state *x;
669
670 if (type != ICMPV6_PKT_TOOBIG &&
671 type != NDISC_REDIRECT)
672 return 0;
673
674 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
675 if (!x)
676 return 0;
677
678 if (type == NDISC_REDIRECT)
679 ip6_redirect(skb, net, skb->dev->ifindex, 0,
680 sock_net_uid(net, NULL));
681 else
682 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
683 xfrm_state_put(x);
684
685 return 0;
686 }
687
ah6_init_state(struct xfrm_state * x,struct netlink_ext_ack * extack)688 static int ah6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
689 {
690 struct ah_data *ahp = NULL;
691 struct xfrm_algo_desc *aalg_desc;
692 struct crypto_ahash *ahash;
693
694 if (!x->aalg) {
695 NL_SET_ERR_MSG(extack, "AH requires a state with an AUTH algorithm");
696 goto error;
697 }
698
699 if (x->encap) {
700 NL_SET_ERR_MSG(extack, "AH is not compatible with encapsulation");
701 goto error;
702 }
703
704 ahp = kzalloc_obj(*ahp);
705 if (!ahp)
706 return -ENOMEM;
707
708 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
709 if (IS_ERR(ahash)) {
710 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
711 goto error;
712 }
713
714 ahp->ahash = ahash;
715 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
716 (x->aalg->alg_key_len + 7) / 8)) {
717 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
718 goto error;
719 }
720
721 /*
722 * Lookup the algorithm description maintained by xfrm_algo,
723 * verify crypto transform properties, and store information
724 * we need for AH processing. This lookup cannot fail here
725 * after a successful crypto_alloc_hash().
726 */
727 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
728 BUG_ON(!aalg_desc);
729
730 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
731 crypto_ahash_digestsize(ahash)) {
732 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
733 goto error;
734 }
735
736 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
737 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
738
739 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
740 ahp->icv_trunc_len);
741 switch (x->props.mode) {
742 case XFRM_MODE_BEET:
743 case XFRM_MODE_TRANSPORT:
744 break;
745 case XFRM_MODE_TUNNEL:
746 x->props.header_len += sizeof(struct ipv6hdr);
747 break;
748 default:
749 NL_SET_ERR_MSG(extack, "Invalid mode requested for AH, must be one of TRANSPORT, TUNNEL, BEET");
750 goto error;
751 }
752 x->data = ahp;
753
754 return 0;
755
756 error:
757 if (ahp) {
758 crypto_free_ahash(ahp->ahash);
759 kfree(ahp);
760 }
761 return -EINVAL;
762 }
763
ah6_destroy(struct xfrm_state * x)764 static void ah6_destroy(struct xfrm_state *x)
765 {
766 struct ah_data *ahp = x->data;
767
768 if (!ahp)
769 return;
770
771 crypto_free_ahash(ahp->ahash);
772 kfree(ahp);
773 }
774
ah6_rcv_cb(struct sk_buff * skb,int err)775 static int ah6_rcv_cb(struct sk_buff *skb, int err)
776 {
777 return 0;
778 }
779
780 static const struct xfrm_type ah6_type = {
781 .owner = THIS_MODULE,
782 .proto = IPPROTO_AH,
783 .flags = XFRM_TYPE_REPLAY_PROT,
784 .init_state = ah6_init_state,
785 .destructor = ah6_destroy,
786 .input = ah6_input,
787 .output = ah6_output,
788 };
789
790 static struct xfrm6_protocol ah6_protocol = {
791 .handler = xfrm6_rcv,
792 .input_handler = xfrm_input,
793 .cb_handler = ah6_rcv_cb,
794 .err_handler = ah6_err,
795 .priority = 0,
796 };
797
ah6_init(void)798 static int __init ah6_init(void)
799 {
800 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
801 pr_info("%s: can't add xfrm type\n", __func__);
802 return -EAGAIN;
803 }
804
805 if (xfrm6_protocol_register(&ah6_protocol, IPPROTO_AH) < 0) {
806 pr_info("%s: can't add protocol\n", __func__);
807 xfrm_unregister_type(&ah6_type, AF_INET6);
808 return -EAGAIN;
809 }
810
811 return 0;
812 }
813
ah6_fini(void)814 static void __exit ah6_fini(void)
815 {
816 if (xfrm6_protocol_deregister(&ah6_protocol, IPPROTO_AH) < 0)
817 pr_info("%s: can't remove protocol\n", __func__);
818
819 xfrm_unregister_type(&ah6_type, AF_INET6);
820 }
821
822 module_init(ah6_init);
823 module_exit(ah6_fini);
824
825 MODULE_DESCRIPTION("IPv6 AH transformation helpers");
826 MODULE_LICENSE("GPL");
827 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);
828