blob: bb02e176cb70537ac7cdc01a03c0c641ab672741 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C)2002 USAGI/WIDE Project
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +09003 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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.
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +09008 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 * 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.
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +090013 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 * 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 *
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +090020 * Mitsuru KANDA @USAGI : IPv6 Support
Linus Torvalds1da177e2005-04-16 15:20:36 -070021 * Kazunori MIYAZAWA @USAGI :
22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +090023 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070024 * This file is derived from net/ipv4/ah.c.
25 */
26
Joe Perchesf3213832012-05-15 14:11:53 +000027#define pr_fmt(fmt) "IPv6: " fmt
28
Steffen Klassert8631e9b2009-10-07 22:49:01 +000029#include <crypto/hash.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <linux/module.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090031#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <net/ip.h>
33#include <net/ah.h>
34#include <linux/crypto.h>
35#include <linux/pfkeyv2.h>
36#include <linux/string.h>
Steffen Klassert8631e9b2009-10-07 22:49:01 +000037#include <linux/scatterlist.h>
David S. Miller81aded22012-06-15 14:54:11 -070038#include <net/ip6_route.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#include <net/icmp.h>
40#include <net/ipv6.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020041#include <net/protocol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <net/xfrm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
Steffen Klassert8631e9b2009-10-07 22:49:01 +000044#define IPV6HDR_BASELEN 8
45
46struct tmp_ext {
Amerigo Wang07a93622012-10-29 16:23:10 +000047#if IS_ENABLED(CONFIG_IPV6_MIP6)
Steffen Klassert8631e9b2009-10-07 22:49:01 +000048 struct in6_addr saddr;
49#endif
50 struct in6_addr daddr;
51 char hdrs[0];
52};
53
54struct 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
61static 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
80static inline struct tmp_ext *ah_tmp_ext(void *base)
81{
82 return base + IPV6HDR_BASELEN;
83}
84
85static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
86{
87 return tmp + offset;
88}
89
90static 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
96static 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
109static 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
Eric Dumazeta50feda2012-05-18 18:57:34 +0000117static bool zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118{
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
Eldad Zack1de5a712012-05-17 06:00:25 +0000131 case IPV6_TLV_PAD1:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 optlen = 1;
133 break;
134 default:
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900135 if (len < 2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 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)
Eric Dumazeta50feda2012-05-18 18:57:34 +0000149 return true;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
151bad:
Eric Dumazeta50feda2012-05-18 18:57:34 +0000152 return false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153}
154
Amerigo Wang07a93622012-10-29 16:23:10 +0000155#if IS_ENABLED(CONFIG_IPV6_MIP6)
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700156/**
157 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
158 * @iph: IPv6 header
159 * @destopt: destionation options header
160 */
161static 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
Eldad Zack1de5a712012-05-17 06:00:25 +0000175 case IPV6_TLV_PAD1:
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700176 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)) {
Joe Perchese87cc472012-05-13 21:56:26 +0000195 net_warn_ratelimited("destopt hao: invalid header length: %u\n",
196 hao->length);
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700197 goto bad;
198 }
Alexey Dobriyan4e3fd7a2011-11-21 03:39:03 +0000199 final_addr = hao->addr;
200 hao->addr = iph->saddr;
201 iph->saddr = final_addr;
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700202 }
203 break;
204 }
205
206 off += optlen;
207 len -= optlen;
208 }
YOSHIFUJI Hideakie731c242006-08-24 23:18:12 +0900209 /* Note: ok if len == 0 */
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700210bad:
211 return;
212}
Masahide NAKAMURA136ebf02007-06-26 23:51:41 -0700213#else
214static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700215#endif
216
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217/**
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 */
226static 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;
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900235 rthdr->segments_left = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
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;
Alexey Dobriyan4e3fd7a2011-11-21 03:39:03 +0000247 final_addr = addrs[segments - 1];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
249 addrs += segments - segments_left;
250 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
251
Alexey Dobriyan4e3fd7a2011-11-21 03:39:03 +0000252 addrs[0] = iph->daddr;
253 iph->daddr = final_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254}
255
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700256static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257{
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) {
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700271 case NEXTHDR_DEST:
272 if (dir == XFRM_POLICY_OUT)
273 ipv6_rearrange_destopt(iph, exthdr.opth);
YOSHIFUJI Hideakie731c242006-08-24 23:18:12 +0900274 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
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
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000299static 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) {
Amerigo Wang07a93622012-10-29 16:23:10 +0000323#if IS_ENABLED(CONFIG_IPV6_MIP6)
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000324 memcpy(&top_iph->saddr, iph_ext, extlen);
325#else
326 memcpy(&top_iph->daddr, iph_ext, extlen);
327#endif
328 }
329
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000330 kfree(AH_SKB_CB(skb)->tmp);
331 xfrm_output_resume(skb, err);
332}
333
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
335{
336 int err;
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000337 int nfrags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 int extlen;
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000339 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 struct ipv6hdr *top_iph;
347 struct ip_auth_hdr *ah;
348 struct ah_data *ahp;
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000349 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357
Herbert Xu7b277b12007-10-10 15:44:06 -0700358 skb_push(skb, -skb_network_offset(skb));
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000359 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
Herbert Xu007f0212007-10-09 13:25:59 -0700376 top_iph = ipv6_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
378
Herbert Xu007f0212007-10-09 13:25:59 -0700379 nexthdr = *skb_mac_header(skb);
380 *skb_mac_header(skb) = IPPROTO_AH;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381
382 /* When there are no extension headers, we only need to save the first
383 * 8 bytes of the base IP header.
384 */
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000385 memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 if (extlen) {
Amerigo Wang07a93622012-10-29 16:23:10 +0000388#if IS_ENABLED(CONFIG_IPV6_MIP6)
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000389 memcpy(iph_ext, &top_iph->saddr, extlen);
YOSHIFUJI Hideakie731c242006-08-24 23:18:12 +0900390#else
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000391 memcpy(iph_ext, &top_iph->daddr, extlen);
YOSHIFUJI Hideakie731c242006-08-24 23:18:12 +0900392#endif
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700393 err = ipv6_clear_mutable_options(top_iph,
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000394 extlen - sizeof(*iph_ext) +
Masahide NAKAMURA27637df2006-08-23 19:29:47 -0700395 sizeof(*top_iph),
396 XFRM_POLICY_OUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 if (err)
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000398 goto out_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 }
400
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 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
Herbert Xu87bdc482007-10-10 15:45:25 -0700409 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410
411 ah->reserved = 0;
412 ah->spi = x->id.spi;
Steffen Klassert1ce36442011-03-08 00:06:31 +0000413 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
Herbert Xub7c65382007-10-09 13:33:35 -0700414
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000415 sg_init_table(sg, nfrags);
416 skb_to_sgvec(skb, sg, 0, skb->len);
Herbert Xub7c65382007-10-09 13:33:35 -0700417
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000418 ahash_request_set_crypt(req, sg, icv, skb->len);
419 ahash_request_set_callback(req, 0, ah6_output_done, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000421 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 }
432
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000433 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
434 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
435
436 if (extlen) {
Amerigo Wang07a93622012-10-29 16:23:10 +0000437#if IS_ENABLED(CONFIG_IPV6_MIP6)
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000438 memcpy(&top_iph->saddr, iph_ext, extlen);
439#else
440 memcpy(&top_iph->daddr, iph_ext, extlen);
441#endif
442 }
443
444out_free:
445 kfree(iph_base);
446out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 return err;
448}
449
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000450static 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
Nick Bowlerb7ea81a2011-11-08 12:12:45 +0000470 err = ah->nexthdr;
471
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000472 skb->network_header += ah_hlen;
473 memcpy(skb_network_header(skb), work_iph, hdr_len);
474 __skb_pull(skb, ah_hlen + hdr_len);
Li RongQinga9403f82013-01-08 15:41:12 +0800475 if (x->props.mode == XFRM_MODE_TUNNEL)
476 skb_reset_transport_header(skb);
477 else
478 skb_set_transport_header(skb, -hdr_len);
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000479out:
480 kfree(AH_SKB_CB(skb)->tmp);
481 xfrm_input_resume(skb, err);
482}
483
484
485
Herbert Xue6956332006-04-01 00:52:46 -0800486static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487{
488 /*
489 * Before process AH
490 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
491 * |<-------------->| hdr_len
492 *
493 * To erase AH:
494 * Keeping copy of cleared headers. After AH processing,
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700495 * Moving the pointer of skb->network_header by using skb_pull as long
496 * as AH header length. Then copy back the copy as long as hdr_len
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 * If destination header following AH exists, copy it into after [Ext2].
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900498 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
500 * There is offset of AH before IPv6 header after the process.
501 */
502
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000503 u8 *auth_data;
504 u8 *icv;
505 u8 *work_iph;
506 struct sk_buff *trailer;
507 struct crypto_ahash *ahash;
508 struct ahash_request *req;
509 struct scatterlist *sg;
Herbert Xu87bdc482007-10-10 15:45:25 -0700510 struct ip_auth_hdr *ah;
Arnaldo Carvalho de Melo0660e032007-04-25 17:54:47 -0700511 struct ipv6hdr *ip6h;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 struct ah_data *ahp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 u16 hdr_len;
514 u16 ah_hlen;
515 int nexthdr;
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000516 int nfrags;
517 int err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518
519 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
520 goto out;
521
522 /* We are going to _remove_ AH header to keep sockets happy,
523 * so... Later this can change. */
Pravin B Shelar14bbd6a2013-02-14 09:44:49 +0000524 if (skb_unclone(skb, GFP_ATOMIC))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 goto out;
526
Herbert Xu7aa68cb2007-10-17 21:30:07 -0700527 skb->ip_summed = CHECKSUM_NONE;
528
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000529 hdr_len = skb_network_header_len(skb);
Herbert Xu87bdc482007-10-10 15:45:25 -0700530 ah = (struct ip_auth_hdr *)skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 ahp = x->data;
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000532 ahash = ahp->ahash;
533
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 nexthdr = ah->nexthdr;
535 ah_hlen = (ah->hdrlen + 2) << 2;
536
Herbert Xu87bdc482007-10-10 15:45:25 -0700537 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
538 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900539 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
541 if (!pskb_may_pull(skb, ah_hlen))
542 goto out;
543
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000544
545 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
546 goto out;
547 nfrags = err;
548
Dang Hongwu4b0ef1f22011-01-11 07:13:33 +0000549 ah = (struct ip_auth_hdr *)skb->data;
550 ip6h = ipv6_hdr(skb);
551
552 skb_push(skb, hdr_len);
553
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000554 work_iph = ah_alloc_tmp(ahash, nfrags, hdr_len + ahp->icv_trunc_len);
555 if (!work_iph)
556 goto out;
557
558 auth_data = ah_tmp_auth(work_iph, hdr_len);
559 icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
560 req = ah_tmp_req(ahash, icv);
561 sg = ah_req_sg(ahash, req);
562
563 memcpy(work_iph, ip6h, hdr_len);
564 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
565 memset(ah->auth_data, 0, ahp->icv_trunc_len);
566
Arnaldo Carvalho de Melo0660e032007-04-25 17:54:47 -0700567 if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000568 goto out_free;
569
Arnaldo Carvalho de Melo0660e032007-04-25 17:54:47 -0700570 ip6h->priority = 0;
571 ip6h->flow_lbl[0] = 0;
572 ip6h->flow_lbl[1] = 0;
573 ip6h->flow_lbl[2] = 0;
574 ip6h->hop_limit = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000576 sg_init_table(sg, nfrags);
577 skb_to_sgvec(skb, sg, 0, skb->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000579 ahash_request_set_crypt(req, sg, icv, skb->len);
580 ahash_request_set_callback(req, 0, ah6_input_done, skb);
581
582 AH_SKB_CB(skb)->tmp = work_iph;
583
584 err = crypto_ahash_digest(req);
585 if (err) {
586 if (err == -EINPROGRESS)
587 goto out;
588
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000589 goto out_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 }
Herbert Xu0ebea8e2007-11-13 21:45:58 -0800591
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000592 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
Herbert Xu0ebea8e2007-11-13 21:45:58 -0800593 if (err)
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000594 goto out_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700596 skb->network_header += ah_hlen;
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000597 memcpy(skb_network_header(skb), work_iph, hdr_len);
Herbert Xu31a4ab92006-05-27 23:06:13 -0700598 __skb_pull(skb, ah_hlen + hdr_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599
Li RongQinga9403f82013-01-08 15:41:12 +0800600 if (x->props.mode == XFRM_MODE_TUNNEL)
601 skb_reset_transport_header(skb);
602 else
603 skb_set_transport_header(skb, -hdr_len);
604
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000605 err = nexthdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000607out_free:
608 kfree(work_iph);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609out:
Herbert Xu07d4ee52006-08-20 14:24:50 +1000610 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611}
612
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900613static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
Brian Haleyd5fdd6b2009-06-23 04:31:07 -0700614 u8 type, u8 code, int offset, __be32 info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615{
Alexey Dobriyan4fb236b2008-11-25 17:59:27 -0800616 struct net *net = dev_net(skb->dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
618 struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+offset);
619 struct xfrm_state *x;
620
621 if (type != ICMPV6_DEST_UNREACH &&
David S. Millerec18d9a2012-07-12 00:25:15 -0700622 type != ICMPV6_PKT_TOOBIG &&
623 type != NDISC_REDIRECT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 return;
625
Jamal Hadi Salimbd557752010-02-22 16:20:22 -0800626 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 if (!x)
628 return;
629
David S. Millerec18d9a2012-07-12 00:25:15 -0700630 if (type == NDISC_REDIRECT)
631 ip6_redirect(skb, net, 0, 0);
632 else
633 ip6_update_pmtu(skb, net, info, 0, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 xfrm_state_put(x);
635}
636
Herbert Xu72cb6962005-06-20 13:18:08 -0700637static int ah6_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638{
639 struct ah_data *ahp = NULL;
640 struct xfrm_algo_desc *aalg_desc;
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000641 struct crypto_ahash *ahash;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642
643 if (!x->aalg)
644 goto error;
645
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 if (x->encap)
647 goto error;
648
Ingo Oeser0c600ed2006-03-20 23:01:32 -0800649 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 if (ahp == NULL)
651 return -ENOMEM;
652
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000653 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
654 if (IS_ERR(ahash))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 goto error;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000656
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000657 ahp->ahash = ahash;
658 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
Herbert Xubc31d3b2007-10-08 17:14:34 -0700659 (x->aalg->alg_key_len + 7) / 8))
Herbert Xu07d4ee52006-08-20 14:24:50 +1000660 goto error;
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900661
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 /*
663 * Lookup the algorithm description maintained by xfrm_algo,
664 * verify crypto transform properties, and store information
665 * we need for AH processing. This lookup cannot fail here
Herbert Xu07d4ee52006-08-20 14:24:50 +1000666 * after a successful crypto_alloc_hash().
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 */
668 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
669 BUG_ON(!aalg_desc);
670
671 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000672 crypto_ahash_digestsize(ahash)) {
Joe Perchesf3213832012-05-15 14:11:53 +0000673 pr_info("AH: %s digestsize %u != %hu\n",
674 x->aalg->alg_name, crypto_ahash_digestsize(ahash),
675 aalg_desc->uinfo.auth.icv_fullbits/8);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 goto error;
677 }
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900678
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
Martin Willi8f8a0882009-11-25 00:29:53 +0000680 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900681
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
YOSHIFUJI Hideaki1ab14572007-02-09 23:24:49 +0900683
Herbert Xu87bdc482007-10-10 15:45:25 -0700684 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
685 ahp->icv_trunc_len);
Herbert Xuca681452007-10-17 21:35:15 -0700686 switch (x->props.mode) {
687 case XFRM_MODE_BEET:
688 case XFRM_MODE_TRANSPORT:
689 break;
690 case XFRM_MODE_TUNNEL:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 x->props.header_len += sizeof(struct ipv6hdr);
Masahide NAKAMURAea2c47b2007-10-22 02:30:15 -0700692 break;
Herbert Xuca681452007-10-17 21:35:15 -0700693 default:
694 goto error;
695 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 x->data = ahp;
697
698 return 0;
699
700error:
701 if (ahp) {
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000702 crypto_free_ahash(ahp->ahash);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 kfree(ahp);
704 }
705 return -EINVAL;
706}
707
708static void ah6_destroy(struct xfrm_state *x)
709{
710 struct ah_data *ahp = x->data;
711
712 if (!ahp)
713 return;
714
Steffen Klassert8631e9b2009-10-07 22:49:01 +0000715 crypto_free_ahash(ahp->ahash);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 kfree(ahp);
717}
718
Eric Dumazet533cb5b2008-01-30 19:11:50 -0800719static const struct xfrm_type ah6_type =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720{
721 .description = "AH6",
722 .owner = THIS_MODULE,
723 .proto = IPPROTO_AH,
Herbert Xu436a0a42007-10-08 17:25:53 -0700724 .flags = XFRM_TYPE_REPLAY_PROT,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 .init_state = ah6_init_state,
726 .destructor = ah6_destroy,
727 .input = ah6_input,
Masahide NAKAMURAaee5adb2006-08-23 17:57:28 -0700728 .output = ah6_output,
729 .hdr_offset = xfrm6_find_1stfragopt,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730};
731
Alexey Dobriyan41135cc2009-09-14 12:22:28 +0000732static const struct inet6_protocol ah6_protocol = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 .handler = xfrm6_rcv,
734 .err_handler = ah6_err,
735 .flags = INET6_PROTO_NOPOLICY,
736};
737
738static int __init ah6_init(void)
739{
740 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
Joe Perchesf3213832012-05-15 14:11:53 +0000741 pr_info("%s: can't add xfrm type\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 return -EAGAIN;
743 }
744
745 if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
Joe Perchesf3213832012-05-15 14:11:53 +0000746 pr_info("%s: can't add protocol\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 xfrm_unregister_type(&ah6_type, AF_INET6);
748 return -EAGAIN;
749 }
750
751 return 0;
752}
753
754static void __exit ah6_fini(void)
755{
756 if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
Joe Perchesf3213832012-05-15 14:11:53 +0000757 pr_info("%s: can't remove protocol\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758
759 if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
Joe Perchesf3213832012-05-15 14:11:53 +0000760 pr_info("%s: can't remove xfrm type\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761
762}
763
764module_init(ah6_init);
765module_exit(ah6_fini);
766
767MODULE_LICENSE("GPL");
Masahide NAKAMURAd3d6dd32007-06-26 23:57:49 -0700768MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);