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1// SPDX-License-Identifier: GPL-2.0-only
2#define pr_fmt(fmt) "IPsec: " fmt
3
4#include <crypto/algapi.h>
5#include <crypto/hash.h>
6#include <linux/err.h>
7#include <linux/module.h>
8#include <linux/slab.h>
9#include <net/ip.h>
10#include <net/xfrm.h>
11#include <net/ah.h>
12#include <linux/crypto.h>
13#include <linux/pfkeyv2.h>
14#include <linux/scatterlist.h>
15#include <net/icmp.h>
16#include <net/protocol.h>
17
18struct ah_skb_cb {
19 struct xfrm_skb_cb xfrm;
20 void *tmp;
21};
22
23#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
24
25static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
26 unsigned int size)
27{
28 unsigned int len;
29
30 len = size + crypto_ahash_digestsize(ahash) +
31 (crypto_ahash_alignmask(ahash) &
32 ~(crypto_tfm_ctx_alignment() - 1));
33
34 len = ALIGN(len, crypto_tfm_ctx_alignment());
35
36 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
37 len = ALIGN(len, __alignof__(struct scatterlist));
38
39 len += sizeof(struct scatterlist) * nfrags;
40
41 return kmalloc(len, GFP_ATOMIC);
42}
43
44static inline u8 *ah_tmp_auth(void *tmp, unsigned int offset)
45{
46 return tmp + offset;
47}
48
49static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
50 unsigned int offset)
51{
52 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
53}
54
55static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
56 u8 *icv)
57{
58 struct ahash_request *req;
59
60 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
61 crypto_tfm_ctx_alignment());
62
63 ahash_request_set_tfm(req, ahash);
64
65 return req;
66}
67
68static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
69 struct ahash_request *req)
70{
71 return (void *)ALIGN((unsigned long)(req + 1) +
72 crypto_ahash_reqsize(ahash),
73 __alignof__(struct scatterlist));
74}
75
76/* Clear mutable options and find final destination to substitute
77 * into IP header for icv calculation. Options are already checked
78 * for validity, so paranoia is not required. */
79
80static int ip_clear_mutable_options(const struct iphdr *iph, __be32 *daddr)
81{
82 unsigned char *optptr = (unsigned char *)(iph+1);
83 int l = iph->ihl*4 - sizeof(struct iphdr);
84 int optlen;
85
86 while (l > 0) {
87 switch (*optptr) {
88 case IPOPT_END:
89 return 0;
90 case IPOPT_NOOP:
91 l--;
92 optptr++;
93 continue;
94 }
95 optlen = optptr[1];
96 if (optlen<2 || optlen>l)
97 return -EINVAL;
98 switch (*optptr) {
99 case IPOPT_SEC:
100 case 0x85: /* Some "Extended Security" crap. */
101 case IPOPT_CIPSO:
102 case IPOPT_RA:
103 case 0x80|21: /* RFC1770 */
104 break;
105 case IPOPT_LSRR:
106 case IPOPT_SSRR:
107 if (optlen < 6)
108 return -EINVAL;
109 memcpy(daddr, optptr+optlen-4, 4);
110 fallthrough;
111 default:
112 memset(optptr, 0, optlen);
113 }
114 l -= optlen;
115 optptr += optlen;
116 }
117 return 0;
118}
119
120static void ah_output_done(struct crypto_async_request *base, int err)
121{
122 u8 *icv;
123 struct iphdr *iph;
124 struct sk_buff *skb = base->data;
125 struct xfrm_state *x = skb_dst(skb)->xfrm;
126 struct ah_data *ahp = x->data;
127 struct iphdr *top_iph = ip_hdr(skb);
128 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
129 int ihl = ip_hdrlen(skb);
130
131 iph = AH_SKB_CB(skb)->tmp;
132 icv = ah_tmp_icv(ahp->ahash, iph, ihl);
133 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
134
135 top_iph->tos = iph->tos;
136 top_iph->ttl = iph->ttl;
137 top_iph->frag_off = iph->frag_off;
138 if (top_iph->ihl != 5) {
139 top_iph->daddr = iph->daddr;
140 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
141 }
142
143 kfree(AH_SKB_CB(skb)->tmp);
144 xfrm_output_resume(skb, err);
145}
146
147static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
148{
149 int err;
150 int nfrags;
151 int ihl;
152 u8 *icv;
153 struct sk_buff *trailer;
154 struct crypto_ahash *ahash;
155 struct ahash_request *req;
156 struct scatterlist *sg;
157 struct iphdr *iph, *top_iph;
158 struct ip_auth_hdr *ah;
159 struct ah_data *ahp;
160 int seqhi_len = 0;
161 __be32 *seqhi;
162 int sglists = 0;
163 struct scatterlist *seqhisg;
164
165 ahp = x->data;
166 ahash = ahp->ahash;
167
168 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
169 goto out;
170 nfrags = err;
171
172 skb_push(skb, -skb_network_offset(skb));
173 ah = ip_auth_hdr(skb);
174 ihl = ip_hdrlen(skb);
175
176 if (x->props.flags & XFRM_STATE_ESN) {
177 sglists = 1;
178 seqhi_len = sizeof(*seqhi);
179 }
180 err = -ENOMEM;
181 iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl + seqhi_len);
182 if (!iph)
183 goto out;
184 seqhi = (__be32 *)((char *)iph + ihl);
185 icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
186 req = ah_tmp_req(ahash, icv);
187 sg = ah_req_sg(ahash, req);
188 seqhisg = sg + nfrags;
189
190 memset(ah->auth_data, 0, ahp->icv_trunc_len);
191
192 top_iph = ip_hdr(skb);
193
194 iph->tos = top_iph->tos;
195 iph->ttl = top_iph->ttl;
196 iph->frag_off = top_iph->frag_off;
197
198 if (top_iph->ihl != 5) {
199 iph->daddr = top_iph->daddr;
200 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
201 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
202 if (err)
203 goto out_free;
204 }
205
206 ah->nexthdr = *skb_mac_header(skb);
207 *skb_mac_header(skb) = IPPROTO_AH;
208
209 top_iph->tos = 0;
210 top_iph->tot_len = htons(skb->len);
211 top_iph->frag_off = 0;
212 top_iph->ttl = 0;
213 top_iph->check = 0;
214
215 if (x->props.flags & XFRM_STATE_ALIGN4)
216 ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
217 else
218 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
219
220 ah->reserved = 0;
221 ah->spi = x->id.spi;
222 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
223
224 sg_init_table(sg, nfrags + sglists);
225 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
226 if (unlikely(err < 0))
227 goto out_free;
228
229 if (x->props.flags & XFRM_STATE_ESN) {
230 /* Attach seqhi sg right after packet payload */
231 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
232 sg_set_buf(seqhisg, seqhi, seqhi_len);
233 }
234 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
235 ahash_request_set_callback(req, 0, ah_output_done, skb);
236
237 AH_SKB_CB(skb)->tmp = iph;
238
239 err = crypto_ahash_digest(req);
240 if (err) {
241 if (err == -EINPROGRESS)
242 goto out;
243
244 if (err == -ENOSPC)
245 err = NET_XMIT_DROP;
246 goto out_free;
247 }
248
249 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
250
251 top_iph->tos = iph->tos;
252 top_iph->ttl = iph->ttl;
253 top_iph->frag_off = iph->frag_off;
254 if (top_iph->ihl != 5) {
255 top_iph->daddr = iph->daddr;
256 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
257 }
258
259out_free:
260 kfree(iph);
261out:
262 return err;
263}
264
265static void ah_input_done(struct crypto_async_request *base, int err)
266{
267 u8 *auth_data;
268 u8 *icv;
269 struct iphdr *work_iph;
270 struct sk_buff *skb = base->data;
271 struct xfrm_state *x = xfrm_input_state(skb);
272 struct ah_data *ahp = x->data;
273 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
274 int ihl = ip_hdrlen(skb);
275 int ah_hlen = (ah->hdrlen + 2) << 2;
276
277 if (err)
278 goto out;
279
280 work_iph = AH_SKB_CB(skb)->tmp;
281 auth_data = ah_tmp_auth(work_iph, ihl);
282 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
283
284 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
285 if (err)
286 goto out;
287
288 err = ah->nexthdr;
289
290 skb->network_header += ah_hlen;
291 memcpy(skb_network_header(skb), work_iph, ihl);
292 __skb_pull(skb, ah_hlen + ihl);
293
294 if (x->props.mode == XFRM_MODE_TUNNEL)
295 skb_reset_transport_header(skb);
296 else
297 skb_set_transport_header(skb, -ihl);
298out:
299 kfree(AH_SKB_CB(skb)->tmp);
300 xfrm_input_resume(skb, err);
301}
302
303static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
304{
305 int ah_hlen;
306 int ihl;
307 int nexthdr;
308 int nfrags;
309 u8 *auth_data;
310 u8 *icv;
311 struct sk_buff *trailer;
312 struct crypto_ahash *ahash;
313 struct ahash_request *req;
314 struct scatterlist *sg;
315 struct iphdr *iph, *work_iph;
316 struct ip_auth_hdr *ah;
317 struct ah_data *ahp;
318 int err = -ENOMEM;
319 int seqhi_len = 0;
320 __be32 *seqhi;
321 int sglists = 0;
322 struct scatterlist *seqhisg;
323
324 if (!pskb_may_pull(skb, sizeof(*ah)))
325 goto out;
326
327 ah = (struct ip_auth_hdr *)skb->data;
328 ahp = x->data;
329 ahash = ahp->ahash;
330
331 nexthdr = ah->nexthdr;
332 ah_hlen = (ah->hdrlen + 2) << 2;
333
334 if (x->props.flags & XFRM_STATE_ALIGN4) {
335 if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
336 ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
337 goto out;
338 } else {
339 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
340 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
341 goto out;
342 }
343
344 if (!pskb_may_pull(skb, ah_hlen))
345 goto out;
346
347 /* We are going to _remove_ AH header to keep sockets happy,
348 * so... Later this can change. */
349 if (skb_unclone(skb, GFP_ATOMIC))
350 goto out;
351
352 skb->ip_summed = CHECKSUM_NONE;
353
354
355 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
356 goto out;
357 nfrags = err;
358
359 ah = (struct ip_auth_hdr *)skb->data;
360 iph = ip_hdr(skb);
361 ihl = ip_hdrlen(skb);
362
363 if (x->props.flags & XFRM_STATE_ESN) {
364 sglists = 1;
365 seqhi_len = sizeof(*seqhi);
366 }
367
368 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, ihl +
369 ahp->icv_trunc_len + seqhi_len);
370 if (!work_iph) {
371 err = -ENOMEM;
372 goto out;
373 }
374
375 seqhi = (__be32 *)((char *)work_iph + ihl);
376 auth_data = ah_tmp_auth(seqhi, seqhi_len);
377 icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
378 req = ah_tmp_req(ahash, icv);
379 sg = ah_req_sg(ahash, req);
380 seqhisg = sg + nfrags;
381
382 memcpy(work_iph, iph, ihl);
383 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
384 memset(ah->auth_data, 0, ahp->icv_trunc_len);
385
386 iph->ttl = 0;
387 iph->tos = 0;
388 iph->frag_off = 0;
389 iph->check = 0;
390 if (ihl > sizeof(*iph)) {
391 __be32 dummy;
392 err = ip_clear_mutable_options(iph, &dummy);
393 if (err)
394 goto out_free;
395 }
396
397 skb_push(skb, ihl);
398
399 sg_init_table(sg, nfrags + sglists);
400 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
401 if (unlikely(err < 0))
402 goto out_free;
403
404 if (x->props.flags & XFRM_STATE_ESN) {
405 /* Attach seqhi sg right after packet payload */
406 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
407 sg_set_buf(seqhisg, seqhi, seqhi_len);
408 }
409 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
410 ahash_request_set_callback(req, 0, ah_input_done, skb);
411
412 AH_SKB_CB(skb)->tmp = work_iph;
413
414 err = crypto_ahash_digest(req);
415 if (err) {
416 if (err == -EINPROGRESS)
417 goto out;
418
419 goto out_free;
420 }
421
422 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
423 if (err)
424 goto out_free;
425
426 skb->network_header += ah_hlen;
427 memcpy(skb_network_header(skb), work_iph, ihl);
428 __skb_pull(skb, ah_hlen + ihl);
429 if (x->props.mode == XFRM_MODE_TUNNEL)
430 skb_reset_transport_header(skb);
431 else
432 skb_set_transport_header(skb, -ihl);
433
434 err = nexthdr;
435
436out_free:
437 kfree (work_iph);
438out:
439 return err;
440}
441
442static int ah4_err(struct sk_buff *skb, u32 info)
443{
444 struct net *net = dev_net(skb->dev);
445 const struct iphdr *iph = (const struct iphdr *)skb->data;
446 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
447 struct xfrm_state *x;
448
449 switch (icmp_hdr(skb)->type) {
450 case ICMP_DEST_UNREACH:
451 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
452 return 0;
453 case ICMP_REDIRECT:
454 break;
455 default:
456 return 0;
457 }
458
459 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
460 ah->spi, IPPROTO_AH, AF_INET);
461 if (!x)
462 return 0;
463
464 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
465 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_AH);
466 else
467 ipv4_redirect(skb, net, 0, IPPROTO_AH);
468 xfrm_state_put(x);
469
470 return 0;
471}
472
473static int ah_init_state(struct xfrm_state *x)
474{
475 struct ah_data *ahp = NULL;
476 struct xfrm_algo_desc *aalg_desc;
477 struct crypto_ahash *ahash;
478
479 if (!x->aalg)
480 goto error;
481
482 if (x->encap)
483 goto error;
484
485 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
486 if (!ahp)
487 return -ENOMEM;
488
489 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
490 if (IS_ERR(ahash))
491 goto error;
492
493 ahp->ahash = ahash;
494 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
495 (x->aalg->alg_key_len + 7) / 8))
496 goto error;
497
498 /*
499 * Lookup the algorithm description maintained by xfrm_algo,
500 * verify crypto transform properties, and store information
501 * we need for AH processing. This lookup cannot fail here
502 * after a successful crypto_alloc_ahash().
503 */
504 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
505 BUG_ON(!aalg_desc);
506
507 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
508 crypto_ahash_digestsize(ahash)) {
509 pr_info("%s: %s digestsize %u != %hu\n",
510 __func__, x->aalg->alg_name,
511 crypto_ahash_digestsize(ahash),
512 aalg_desc->uinfo.auth.icv_fullbits / 8);
513 goto error;
514 }
515
516 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
517 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
518
519 if (x->props.flags & XFRM_STATE_ALIGN4)
520 x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
521 ahp->icv_trunc_len);
522 else
523 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
524 ahp->icv_trunc_len);
525 if (x->props.mode == XFRM_MODE_TUNNEL)
526 x->props.header_len += sizeof(struct iphdr);
527 x->data = ahp;
528
529 return 0;
530
531error:
532 if (ahp) {
533 crypto_free_ahash(ahp->ahash);
534 kfree(ahp);
535 }
536 return -EINVAL;
537}
538
539static void ah_destroy(struct xfrm_state *x)
540{
541 struct ah_data *ahp = x->data;
542
543 if (!ahp)
544 return;
545
546 crypto_free_ahash(ahp->ahash);
547 kfree(ahp);
548}
549
550static int ah4_rcv_cb(struct sk_buff *skb, int err)
551{
552 return 0;
553}
554
555static const struct xfrm_type ah_type =
556{
557 .description = "AH4",
558 .owner = THIS_MODULE,
559 .proto = IPPROTO_AH,
560 .flags = XFRM_TYPE_REPLAY_PROT,
561 .init_state = ah_init_state,
562 .destructor = ah_destroy,
563 .input = ah_input,
564 .output = ah_output
565};
566
567static struct xfrm4_protocol ah4_protocol = {
568 .handler = xfrm4_rcv,
569 .input_handler = xfrm_input,
570 .cb_handler = ah4_rcv_cb,
571 .err_handler = ah4_err,
572 .priority = 0,
573};
574
575static int __init ah4_init(void)
576{
577 if (xfrm_register_type(&ah_type, AF_INET) < 0) {
578 pr_info("%s: can't add xfrm type\n", __func__);
579 return -EAGAIN;
580 }
581 if (xfrm4_protocol_register(&ah4_protocol, IPPROTO_AH) < 0) {
582 pr_info("%s: can't add protocol\n", __func__);
583 xfrm_unregister_type(&ah_type, AF_INET);
584 return -EAGAIN;
585 }
586 return 0;
587}
588
589static void __exit ah4_fini(void)
590{
591 if (xfrm4_protocol_deregister(&ah4_protocol, IPPROTO_AH) < 0)
592 pr_info("%s: can't remove protocol\n", __func__);
593 xfrm_unregister_type(&ah_type, AF_INET);
594}
595
596module_init(ah4_init);
597module_exit(ah4_fini);
598MODULE_LICENSE("GPL");
599MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);
1#include <crypto/hash.h>
2#include <linux/err.h>
3#include <linux/module.h>
4#include <linux/slab.h>
5#include <net/ip.h>
6#include <net/xfrm.h>
7#include <net/ah.h>
8#include <linux/crypto.h>
9#include <linux/pfkeyv2.h>
10#include <linux/scatterlist.h>
11#include <net/icmp.h>
12#include <net/protocol.h>
13
14struct ah_skb_cb {
15 struct xfrm_skb_cb xfrm;
16 void *tmp;
17};
18
19#define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
20
21static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
22 unsigned int size)
23{
24 unsigned int len;
25
26 len = size + crypto_ahash_digestsize(ahash) +
27 (crypto_ahash_alignmask(ahash) &
28 ~(crypto_tfm_ctx_alignment() - 1));
29
30 len = ALIGN(len, crypto_tfm_ctx_alignment());
31
32 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
33 len = ALIGN(len, __alignof__(struct scatterlist));
34
35 len += sizeof(struct scatterlist) * nfrags;
36
37 return kmalloc(len, GFP_ATOMIC);
38}
39
40static inline u8 *ah_tmp_auth(void *tmp, unsigned int offset)
41{
42 return tmp + offset;
43}
44
45static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
46 unsigned int offset)
47{
48 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
49}
50
51static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
52 u8 *icv)
53{
54 struct ahash_request *req;
55
56 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
57 crypto_tfm_ctx_alignment());
58
59 ahash_request_set_tfm(req, ahash);
60
61 return req;
62}
63
64static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
65 struct ahash_request *req)
66{
67 return (void *)ALIGN((unsigned long)(req + 1) +
68 crypto_ahash_reqsize(ahash),
69 __alignof__(struct scatterlist));
70}
71
72/* Clear mutable options and find final destination to substitute
73 * into IP header for icv calculation. Options are already checked
74 * for validity, so paranoia is not required. */
75
76static int ip_clear_mutable_options(const struct iphdr *iph, __be32 *daddr)
77{
78 unsigned char * optptr = (unsigned char*)(iph+1);
79 int l = iph->ihl*4 - sizeof(struct iphdr);
80 int optlen;
81
82 while (l > 0) {
83 switch (*optptr) {
84 case IPOPT_END:
85 return 0;
86 case IPOPT_NOOP:
87 l--;
88 optptr++;
89 continue;
90 }
91 optlen = optptr[1];
92 if (optlen<2 || optlen>l)
93 return -EINVAL;
94 switch (*optptr) {
95 case IPOPT_SEC:
96 case 0x85: /* Some "Extended Security" crap. */
97 case IPOPT_CIPSO:
98 case IPOPT_RA:
99 case 0x80|21: /* RFC1770 */
100 break;
101 case IPOPT_LSRR:
102 case IPOPT_SSRR:
103 if (optlen < 6)
104 return -EINVAL;
105 memcpy(daddr, optptr+optlen-4, 4);
106 /* Fall through */
107 default:
108 memset(optptr, 0, optlen);
109 }
110 l -= optlen;
111 optptr += optlen;
112 }
113 return 0;
114}
115
116static void ah_output_done(struct crypto_async_request *base, int err)
117{
118 u8 *icv;
119 struct iphdr *iph;
120 struct sk_buff *skb = base->data;
121 struct xfrm_state *x = skb_dst(skb)->xfrm;
122 struct ah_data *ahp = x->data;
123 struct iphdr *top_iph = ip_hdr(skb);
124 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
125 int ihl = ip_hdrlen(skb);
126
127 iph = AH_SKB_CB(skb)->tmp;
128 icv = ah_tmp_icv(ahp->ahash, iph, ihl);
129 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
130
131 top_iph->tos = iph->tos;
132 top_iph->ttl = iph->ttl;
133 top_iph->frag_off = iph->frag_off;
134 if (top_iph->ihl != 5) {
135 top_iph->daddr = iph->daddr;
136 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
137 }
138
139 err = ah->nexthdr;
140
141 kfree(AH_SKB_CB(skb)->tmp);
142 xfrm_output_resume(skb, err);
143}
144
145static int ah_output(struct xfrm_state *x, struct sk_buff *skb)
146{
147 int err;
148 int nfrags;
149 int ihl;
150 u8 *icv;
151 struct sk_buff *trailer;
152 struct crypto_ahash *ahash;
153 struct ahash_request *req;
154 struct scatterlist *sg;
155 struct iphdr *iph, *top_iph;
156 struct ip_auth_hdr *ah;
157 struct ah_data *ahp;
158
159 ahp = x->data;
160 ahash = ahp->ahash;
161
162 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
163 goto out;
164 nfrags = err;
165
166 skb_push(skb, -skb_network_offset(skb));
167 ah = ip_auth_hdr(skb);
168 ihl = ip_hdrlen(skb);
169
170 err = -ENOMEM;
171 iph = ah_alloc_tmp(ahash, nfrags, ihl);
172 if (!iph)
173 goto out;
174
175 icv = ah_tmp_icv(ahash, iph, ihl);
176 req = ah_tmp_req(ahash, icv);
177 sg = ah_req_sg(ahash, req);
178
179 memset(ah->auth_data, 0, ahp->icv_trunc_len);
180
181 top_iph = ip_hdr(skb);
182
183 iph->tos = top_iph->tos;
184 iph->ttl = top_iph->ttl;
185 iph->frag_off = top_iph->frag_off;
186
187 if (top_iph->ihl != 5) {
188 iph->daddr = top_iph->daddr;
189 memcpy(iph+1, top_iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
190 err = ip_clear_mutable_options(top_iph, &top_iph->daddr);
191 if (err)
192 goto out_free;
193 }
194
195 ah->nexthdr = *skb_mac_header(skb);
196 *skb_mac_header(skb) = IPPROTO_AH;
197
198 top_iph->tos = 0;
199 top_iph->tot_len = htons(skb->len);
200 top_iph->frag_off = 0;
201 top_iph->ttl = 0;
202 top_iph->check = 0;
203
204 if (x->props.flags & XFRM_STATE_ALIGN4)
205 ah->hdrlen = (XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
206 else
207 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
208
209 ah->reserved = 0;
210 ah->spi = x->id.spi;
211 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
212
213 sg_init_table(sg, nfrags);
214 skb_to_sgvec(skb, sg, 0, skb->len);
215
216 ahash_request_set_crypt(req, sg, icv, skb->len);
217 ahash_request_set_callback(req, 0, ah_output_done, skb);
218
219 AH_SKB_CB(skb)->tmp = iph;
220
221 err = crypto_ahash_digest(req);
222 if (err) {
223 if (err == -EINPROGRESS)
224 goto out;
225
226 if (err == -EBUSY)
227 err = NET_XMIT_DROP;
228 goto out_free;
229 }
230
231 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
232
233 top_iph->tos = iph->tos;
234 top_iph->ttl = iph->ttl;
235 top_iph->frag_off = iph->frag_off;
236 if (top_iph->ihl != 5) {
237 top_iph->daddr = iph->daddr;
238 memcpy(top_iph+1, iph+1, top_iph->ihl*4 - sizeof(struct iphdr));
239 }
240
241out_free:
242 kfree(iph);
243out:
244 return err;
245}
246
247static void ah_input_done(struct crypto_async_request *base, int err)
248{
249 u8 *auth_data;
250 u8 *icv;
251 struct iphdr *work_iph;
252 struct sk_buff *skb = base->data;
253 struct xfrm_state *x = xfrm_input_state(skb);
254 struct ah_data *ahp = x->data;
255 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
256 int ihl = ip_hdrlen(skb);
257 int ah_hlen = (ah->hdrlen + 2) << 2;
258
259 work_iph = AH_SKB_CB(skb)->tmp;
260 auth_data = ah_tmp_auth(work_iph, ihl);
261 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
262
263 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
264 if (err)
265 goto out;
266
267 skb->network_header += ah_hlen;
268 memcpy(skb_network_header(skb), work_iph, ihl);
269 __skb_pull(skb, ah_hlen + ihl);
270 skb_set_transport_header(skb, -ihl);
271
272 err = ah->nexthdr;
273out:
274 kfree(AH_SKB_CB(skb)->tmp);
275 xfrm_input_resume(skb, err);
276}
277
278static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
279{
280 int ah_hlen;
281 int ihl;
282 int nexthdr;
283 int nfrags;
284 u8 *auth_data;
285 u8 *icv;
286 struct sk_buff *trailer;
287 struct crypto_ahash *ahash;
288 struct ahash_request *req;
289 struct scatterlist *sg;
290 struct iphdr *iph, *work_iph;
291 struct ip_auth_hdr *ah;
292 struct ah_data *ahp;
293 int err = -ENOMEM;
294
295 if (!pskb_may_pull(skb, sizeof(*ah)))
296 goto out;
297
298 ah = (struct ip_auth_hdr *)skb->data;
299 ahp = x->data;
300 ahash = ahp->ahash;
301
302 nexthdr = ah->nexthdr;
303 ah_hlen = (ah->hdrlen + 2) << 2;
304
305 if (x->props.flags & XFRM_STATE_ALIGN4) {
306 if (ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_full_len) &&
307 ah_hlen != XFRM_ALIGN4(sizeof(*ah) + ahp->icv_trunc_len))
308 goto out;
309 } else {
310 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
311 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
312 goto out;
313 }
314
315 if (!pskb_may_pull(skb, ah_hlen))
316 goto out;
317
318 /* We are going to _remove_ AH header to keep sockets happy,
319 * so... Later this can change. */
320 if (skb_cloned(skb) &&
321 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
322 goto out;
323
324 skb->ip_summed = CHECKSUM_NONE;
325
326
327 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
328 goto out;
329 nfrags = err;
330
331 ah = (struct ip_auth_hdr *)skb->data;
332 iph = ip_hdr(skb);
333 ihl = ip_hdrlen(skb);
334
335 work_iph = ah_alloc_tmp(ahash, nfrags, ihl + ahp->icv_trunc_len);
336 if (!work_iph)
337 goto out;
338
339 auth_data = ah_tmp_auth(work_iph, ihl);
340 icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
341 req = ah_tmp_req(ahash, icv);
342 sg = ah_req_sg(ahash, req);
343
344 memcpy(work_iph, iph, ihl);
345 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
346 memset(ah->auth_data, 0, ahp->icv_trunc_len);
347
348 iph->ttl = 0;
349 iph->tos = 0;
350 iph->frag_off = 0;
351 iph->check = 0;
352 if (ihl > sizeof(*iph)) {
353 __be32 dummy;
354 err = ip_clear_mutable_options(iph, &dummy);
355 if (err)
356 goto out_free;
357 }
358
359 skb_push(skb, ihl);
360
361 sg_init_table(sg, nfrags);
362 skb_to_sgvec(skb, sg, 0, skb->len);
363
364 ahash_request_set_crypt(req, sg, icv, skb->len);
365 ahash_request_set_callback(req, 0, ah_input_done, skb);
366
367 AH_SKB_CB(skb)->tmp = work_iph;
368
369 err = crypto_ahash_digest(req);
370 if (err) {
371 if (err == -EINPROGRESS)
372 goto out;
373
374 if (err == -EBUSY)
375 err = NET_XMIT_DROP;
376 goto out_free;
377 }
378
379 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
380 if (err)
381 goto out_free;
382
383 skb->network_header += ah_hlen;
384 memcpy(skb_network_header(skb), work_iph, ihl);
385 __skb_pull(skb, ah_hlen + ihl);
386 skb_set_transport_header(skb, -ihl);
387
388 err = nexthdr;
389
390out_free:
391 kfree (work_iph);
392out:
393 return err;
394}
395
396static void ah4_err(struct sk_buff *skb, u32 info)
397{
398 struct net *net = dev_net(skb->dev);
399 const struct iphdr *iph = (const struct iphdr *)skb->data;
400 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
401 struct xfrm_state *x;
402
403 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
404 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
405 return;
406
407 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
408 ah->spi, IPPROTO_AH, AF_INET);
409 if (!x)
410 return;
411 printk(KERN_DEBUG "pmtu discovery on SA AH/%08x/%08x\n",
412 ntohl(ah->spi), ntohl(iph->daddr));
413 xfrm_state_put(x);
414}
415
416static int ah_init_state(struct xfrm_state *x)
417{
418 struct ah_data *ahp = NULL;
419 struct xfrm_algo_desc *aalg_desc;
420 struct crypto_ahash *ahash;
421
422 if (!x->aalg)
423 goto error;
424
425 if (x->encap)
426 goto error;
427
428 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
429 if (!ahp)
430 return -ENOMEM;
431
432 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
433 if (IS_ERR(ahash))
434 goto error;
435
436 ahp->ahash = ahash;
437 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
438 (x->aalg->alg_key_len + 7) / 8))
439 goto error;
440
441 /*
442 * Lookup the algorithm description maintained by xfrm_algo,
443 * verify crypto transform properties, and store information
444 * we need for AH processing. This lookup cannot fail here
445 * after a successful crypto_alloc_ahash().
446 */
447 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
448 BUG_ON(!aalg_desc);
449
450 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
451 crypto_ahash_digestsize(ahash)) {
452 printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
453 x->aalg->alg_name, crypto_ahash_digestsize(ahash),
454 aalg_desc->uinfo.auth.icv_fullbits/8);
455 goto error;
456 }
457
458 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
459 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
460
461 BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
462
463 if (x->props.flags & XFRM_STATE_ALIGN4)
464 x->props.header_len = XFRM_ALIGN4(sizeof(struct ip_auth_hdr) +
465 ahp->icv_trunc_len);
466 else
467 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
468 ahp->icv_trunc_len);
469 if (x->props.mode == XFRM_MODE_TUNNEL)
470 x->props.header_len += sizeof(struct iphdr);
471 x->data = ahp;
472
473 return 0;
474
475error:
476 if (ahp) {
477 crypto_free_ahash(ahp->ahash);
478 kfree(ahp);
479 }
480 return -EINVAL;
481}
482
483static void ah_destroy(struct xfrm_state *x)
484{
485 struct ah_data *ahp = x->data;
486
487 if (!ahp)
488 return;
489
490 crypto_free_ahash(ahp->ahash);
491 kfree(ahp);
492}
493
494
495static const struct xfrm_type ah_type =
496{
497 .description = "AH4",
498 .owner = THIS_MODULE,
499 .proto = IPPROTO_AH,
500 .flags = XFRM_TYPE_REPLAY_PROT,
501 .init_state = ah_init_state,
502 .destructor = ah_destroy,
503 .input = ah_input,
504 .output = ah_output
505};
506
507static const struct net_protocol ah4_protocol = {
508 .handler = xfrm4_rcv,
509 .err_handler = ah4_err,
510 .no_policy = 1,
511 .netns_ok = 1,
512};
513
514static int __init ah4_init(void)
515{
516 if (xfrm_register_type(&ah_type, AF_INET) < 0) {
517 printk(KERN_INFO "ip ah init: can't add xfrm type\n");
518 return -EAGAIN;
519 }
520 if (inet_add_protocol(&ah4_protocol, IPPROTO_AH) < 0) {
521 printk(KERN_INFO "ip ah init: can't add protocol\n");
522 xfrm_unregister_type(&ah_type, AF_INET);
523 return -EAGAIN;
524 }
525 return 0;
526}
527
528static void __exit ah4_fini(void)
529{
530 if (inet_del_protocol(&ah4_protocol, IPPROTO_AH) < 0)
531 printk(KERN_INFO "ip ah close: can't remove protocol\n");
532 if (xfrm_unregister_type(&ah_type, AF_INET) < 0)
533 printk(KERN_INFO "ip ah close: can't remove xfrm type\n");
534}
535
536module_init(ah4_init);
537module_exit(ah4_fini);
538MODULE_LICENSE("GPL");
539MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_AH);