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1/*
2 * Copyright (C)2002 USAGI/WIDE Project
3 *
4 * 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.
8 *
9 * 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.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 *
17 * Authors
18 *
19 * Mitsuru KANDA @USAGI : IPv6 Support
20 * Kazunori MIYAZAWA @USAGI :
21 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
22 *
23 * This file is derived from net/ipv4/esp.c
24 */
25
26#define pr_fmt(fmt) "IPv6: " fmt
27
28#include <crypto/aead.h>
29#include <crypto/authenc.h>
30#include <linux/err.h>
31#include <linux/module.h>
32#include <net/ip.h>
33#include <net/xfrm.h>
34#include <net/esp.h>
35#include <linux/scatterlist.h>
36#include <linux/kernel.h>
37#include <linux/pfkeyv2.h>
38#include <linux/random.h>
39#include <linux/slab.h>
40#include <linux/spinlock.h>
41#include <net/ip6_route.h>
42#include <net/icmp.h>
43#include <net/ipv6.h>
44#include <net/protocol.h>
45#include <linux/icmpv6.h>
46
47struct esp_skb_cb {
48 struct xfrm_skb_cb xfrm;
49 void *tmp;
50};
51
52#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
53
54static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
55
56/*
57 * Allocate an AEAD request structure with extra space for SG and IV.
58 *
59 * For alignment considerations the upper 32 bits of the sequence number are
60 * placed at the front, if present. Followed by the IV, the request and finally
61 * the SG list.
62 *
63 * TODO: Use spare space in skb for this where possible.
64 */
65static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
66{
67 unsigned int len;
68
69 len = seqihlen;
70
71 len += crypto_aead_ivsize(aead);
72
73 if (len) {
74 len += crypto_aead_alignmask(aead) &
75 ~(crypto_tfm_ctx_alignment() - 1);
76 len = ALIGN(len, crypto_tfm_ctx_alignment());
77 }
78
79 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
80 len = ALIGN(len, __alignof__(struct scatterlist));
81
82 len += sizeof(struct scatterlist) * nfrags;
83
84 return kmalloc(len, GFP_ATOMIC);
85}
86
87static inline __be32 *esp_tmp_seqhi(void *tmp)
88{
89 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
90}
91
92static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
93{
94 return crypto_aead_ivsize(aead) ?
95 PTR_ALIGN((u8 *)tmp + seqhilen,
96 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
97}
98
99static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
100{
101 struct aead_request *req;
102
103 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
104 crypto_tfm_ctx_alignment());
105 aead_request_set_tfm(req, aead);
106 return req;
107}
108
109static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
110 struct aead_request *req)
111{
112 return (void *)ALIGN((unsigned long)(req + 1) +
113 crypto_aead_reqsize(aead),
114 __alignof__(struct scatterlist));
115}
116
117static void esp_output_done(struct crypto_async_request *base, int err)
118{
119 struct sk_buff *skb = base->data;
120
121 kfree(ESP_SKB_CB(skb)->tmp);
122 xfrm_output_resume(skb, err);
123}
124
125/* Move ESP header back into place. */
126static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
127{
128 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
129 void *tmp = ESP_SKB_CB(skb)->tmp;
130 __be32 *seqhi = esp_tmp_seqhi(tmp);
131
132 esph->seq_no = esph->spi;
133 esph->spi = *seqhi;
134}
135
136static void esp_output_restore_header(struct sk_buff *skb)
137{
138 esp_restore_header(skb, skb_transport_offset(skb) - sizeof(__be32));
139}
140
141static void esp_output_done_esn(struct crypto_async_request *base, int err)
142{
143 struct sk_buff *skb = base->data;
144
145 esp_output_restore_header(skb);
146 esp_output_done(base, err);
147}
148
149static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
150{
151 int err;
152 struct ip_esp_hdr *esph;
153 struct crypto_aead *aead;
154 struct aead_request *req;
155 struct scatterlist *sg;
156 struct sk_buff *trailer;
157 void *tmp;
158 int blksize;
159 int clen;
160 int alen;
161 int plen;
162 int ivlen;
163 int tfclen;
164 int nfrags;
165 int assoclen;
166 int seqhilen;
167 u8 *iv;
168 u8 *tail;
169 __be32 *seqhi;
170 __be64 seqno;
171
172 /* skb is pure payload to encrypt */
173 aead = x->data;
174 alen = crypto_aead_authsize(aead);
175 ivlen = crypto_aead_ivsize(aead);
176
177 tfclen = 0;
178 if (x->tfcpad) {
179 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
180 u32 padto;
181
182 padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
183 if (skb->len < padto)
184 tfclen = padto - skb->len;
185 }
186 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
187 clen = ALIGN(skb->len + 2 + tfclen, blksize);
188 plen = clen - skb->len - tfclen;
189
190 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
191 if (err < 0)
192 goto error;
193 nfrags = err;
194
195 assoclen = sizeof(*esph);
196 seqhilen = 0;
197
198 if (x->props.flags & XFRM_STATE_ESN) {
199 seqhilen += sizeof(__be32);
200 assoclen += seqhilen;
201 }
202
203 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
204 if (!tmp) {
205 err = -ENOMEM;
206 goto error;
207 }
208
209 seqhi = esp_tmp_seqhi(tmp);
210 iv = esp_tmp_iv(aead, tmp, seqhilen);
211 req = esp_tmp_req(aead, iv);
212 sg = esp_req_sg(aead, req);
213
214 /* Fill padding... */
215 tail = skb_tail_pointer(trailer);
216 if (tfclen) {
217 memset(tail, 0, tfclen);
218 tail += tfclen;
219 }
220 do {
221 int i;
222 for (i = 0; i < plen - 2; i++)
223 tail[i] = i + 1;
224 } while (0);
225 tail[plen - 2] = plen - 2;
226 tail[plen - 1] = *skb_mac_header(skb);
227 pskb_put(skb, trailer, clen - skb->len + alen);
228
229 skb_push(skb, -skb_network_offset(skb));
230 esph = ip_esp_hdr(skb);
231 *skb_mac_header(skb) = IPPROTO_ESP;
232
233 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
234
235 aead_request_set_callback(req, 0, esp_output_done, skb);
236
237 /* For ESN we move the header forward by 4 bytes to
238 * accomodate the high bits. We will move it back after
239 * encryption.
240 */
241 if ((x->props.flags & XFRM_STATE_ESN)) {
242 esph = (void *)(skb_transport_header(skb) - sizeof(__be32));
243 *seqhi = esph->spi;
244 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
245 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
246 }
247
248 esph->spi = x->id.spi;
249
250 sg_init_table(sg, nfrags);
251 skb_to_sgvec(skb, sg,
252 (unsigned char *)esph - skb->data,
253 assoclen + ivlen + clen + alen);
254
255 aead_request_set_crypt(req, sg, sg, ivlen + clen, iv);
256 aead_request_set_ad(req, assoclen);
257
258 seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
259 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
260
261 memset(iv, 0, ivlen);
262 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&seqno + 8 - min(ivlen, 8),
263 min(ivlen, 8));
264
265 ESP_SKB_CB(skb)->tmp = tmp;
266 err = crypto_aead_encrypt(req);
267
268 switch (err) {
269 case -EINPROGRESS:
270 goto error;
271
272 case -EBUSY:
273 err = NET_XMIT_DROP;
274 break;
275
276 case 0:
277 if ((x->props.flags & XFRM_STATE_ESN))
278 esp_output_restore_header(skb);
279 }
280
281 kfree(tmp);
282
283error:
284 return err;
285}
286
287static int esp_input_done2(struct sk_buff *skb, int err)
288{
289 struct xfrm_state *x = xfrm_input_state(skb);
290 struct crypto_aead *aead = x->data;
291 int alen = crypto_aead_authsize(aead);
292 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
293 int elen = skb->len - hlen;
294 int hdr_len = skb_network_header_len(skb);
295 int padlen;
296 u8 nexthdr[2];
297
298 kfree(ESP_SKB_CB(skb)->tmp);
299
300 if (unlikely(err))
301 goto out;
302
303 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
304 BUG();
305
306 err = -EINVAL;
307 padlen = nexthdr[0];
308 if (padlen + 2 + alen >= elen) {
309 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
310 padlen + 2, elen - alen);
311 goto out;
312 }
313
314 /* ... check padding bits here. Silly. :-) */
315
316 pskb_trim(skb, skb->len - alen - padlen - 2);
317 __skb_pull(skb, hlen);
318 if (x->props.mode == XFRM_MODE_TUNNEL)
319 skb_reset_transport_header(skb);
320 else
321 skb_set_transport_header(skb, -hdr_len);
322
323 err = nexthdr[1];
324
325 /* RFC4303: Drop dummy packets without any error */
326 if (err == IPPROTO_NONE)
327 err = -EINVAL;
328
329out:
330 return err;
331}
332
333static void esp_input_done(struct crypto_async_request *base, int err)
334{
335 struct sk_buff *skb = base->data;
336
337 xfrm_input_resume(skb, esp_input_done2(skb, err));
338}
339
340static void esp_input_restore_header(struct sk_buff *skb)
341{
342 esp_restore_header(skb, 0);
343 __skb_pull(skb, 4);
344}
345
346static void esp_input_done_esn(struct crypto_async_request *base, int err)
347{
348 struct sk_buff *skb = base->data;
349
350 esp_input_restore_header(skb);
351 esp_input_done(base, err);
352}
353
354static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
355{
356 struct ip_esp_hdr *esph;
357 struct crypto_aead *aead = x->data;
358 struct aead_request *req;
359 struct sk_buff *trailer;
360 int ivlen = crypto_aead_ivsize(aead);
361 int elen = skb->len - sizeof(*esph) - ivlen;
362 int nfrags;
363 int assoclen;
364 int seqhilen;
365 int ret = 0;
366 void *tmp;
367 __be32 *seqhi;
368 u8 *iv;
369 struct scatterlist *sg;
370
371 if (!pskb_may_pull(skb, sizeof(*esph) + ivlen)) {
372 ret = -EINVAL;
373 goto out;
374 }
375
376 if (elen <= 0) {
377 ret = -EINVAL;
378 goto out;
379 }
380
381 nfrags = skb_cow_data(skb, 0, &trailer);
382 if (nfrags < 0) {
383 ret = -EINVAL;
384 goto out;
385 }
386
387 ret = -ENOMEM;
388
389 assoclen = sizeof(*esph);
390 seqhilen = 0;
391
392 if (x->props.flags & XFRM_STATE_ESN) {
393 seqhilen += sizeof(__be32);
394 assoclen += seqhilen;
395 }
396
397 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
398 if (!tmp)
399 goto out;
400
401 ESP_SKB_CB(skb)->tmp = tmp;
402 seqhi = esp_tmp_seqhi(tmp);
403 iv = esp_tmp_iv(aead, tmp, seqhilen);
404 req = esp_tmp_req(aead, iv);
405 sg = esp_req_sg(aead, req);
406
407 skb->ip_summed = CHECKSUM_NONE;
408
409 esph = (struct ip_esp_hdr *)skb->data;
410
411 aead_request_set_callback(req, 0, esp_input_done, skb);
412
413 /* For ESN we move the header forward by 4 bytes to
414 * accomodate the high bits. We will move it back after
415 * decryption.
416 */
417 if ((x->props.flags & XFRM_STATE_ESN)) {
418 esph = (void *)skb_push(skb, 4);
419 *seqhi = esph->spi;
420 esph->spi = esph->seq_no;
421 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.input.hi);
422 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
423 }
424
425 sg_init_table(sg, nfrags);
426 skb_to_sgvec(skb, sg, 0, skb->len);
427
428 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
429 aead_request_set_ad(req, assoclen);
430
431 ret = crypto_aead_decrypt(req);
432 if (ret == -EINPROGRESS)
433 goto out;
434
435 if ((x->props.flags & XFRM_STATE_ESN))
436 esp_input_restore_header(skb);
437
438 ret = esp_input_done2(skb, ret);
439
440out:
441 return ret;
442}
443
444static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
445{
446 struct crypto_aead *aead = x->data;
447 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
448 unsigned int net_adj;
449
450 if (x->props.mode != XFRM_MODE_TUNNEL)
451 net_adj = sizeof(struct ipv6hdr);
452 else
453 net_adj = 0;
454
455 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
456 net_adj) & ~(blksize - 1)) + net_adj - 2;
457}
458
459static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
460 u8 type, u8 code, int offset, __be32 info)
461{
462 struct net *net = dev_net(skb->dev);
463 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
464 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
465 struct xfrm_state *x;
466
467 if (type != ICMPV6_PKT_TOOBIG &&
468 type != NDISC_REDIRECT)
469 return 0;
470
471 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
472 esph->spi, IPPROTO_ESP, AF_INET6);
473 if (!x)
474 return 0;
475
476 if (type == NDISC_REDIRECT)
477 ip6_redirect(skb, net, skb->dev->ifindex, 0);
478 else
479 ip6_update_pmtu(skb, net, info, 0, 0);
480 xfrm_state_put(x);
481
482 return 0;
483}
484
485static void esp6_destroy(struct xfrm_state *x)
486{
487 struct crypto_aead *aead = x->data;
488
489 if (!aead)
490 return;
491
492 crypto_free_aead(aead);
493}
494
495static int esp_init_aead(struct xfrm_state *x)
496{
497 char aead_name[CRYPTO_MAX_ALG_NAME];
498 struct crypto_aead *aead;
499 int err;
500
501 err = -ENAMETOOLONG;
502 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
503 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
504 goto error;
505
506 aead = crypto_alloc_aead(aead_name, 0, 0);
507 err = PTR_ERR(aead);
508 if (IS_ERR(aead))
509 goto error;
510
511 x->data = aead;
512
513 err = crypto_aead_setkey(aead, x->aead->alg_key,
514 (x->aead->alg_key_len + 7) / 8);
515 if (err)
516 goto error;
517
518 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
519 if (err)
520 goto error;
521
522error:
523 return err;
524}
525
526static int esp_init_authenc(struct xfrm_state *x)
527{
528 struct crypto_aead *aead;
529 struct crypto_authenc_key_param *param;
530 struct rtattr *rta;
531 char *key;
532 char *p;
533 char authenc_name[CRYPTO_MAX_ALG_NAME];
534 unsigned int keylen;
535 int err;
536
537 err = -EINVAL;
538 if (!x->ealg)
539 goto error;
540
541 err = -ENAMETOOLONG;
542
543 if ((x->props.flags & XFRM_STATE_ESN)) {
544 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
545 "%s%sauthencesn(%s,%s)%s",
546 x->geniv ?: "", x->geniv ? "(" : "",
547 x->aalg ? x->aalg->alg_name : "digest_null",
548 x->ealg->alg_name,
549 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
550 goto error;
551 } else {
552 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
553 "%s%sauthenc(%s,%s)%s",
554 x->geniv ?: "", x->geniv ? "(" : "",
555 x->aalg ? x->aalg->alg_name : "digest_null",
556 x->ealg->alg_name,
557 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
558 goto error;
559 }
560
561 aead = crypto_alloc_aead(authenc_name, 0, 0);
562 err = PTR_ERR(aead);
563 if (IS_ERR(aead))
564 goto error;
565
566 x->data = aead;
567
568 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
569 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
570 err = -ENOMEM;
571 key = kmalloc(keylen, GFP_KERNEL);
572 if (!key)
573 goto error;
574
575 p = key;
576 rta = (void *)p;
577 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
578 rta->rta_len = RTA_LENGTH(sizeof(*param));
579 param = RTA_DATA(rta);
580 p += RTA_SPACE(sizeof(*param));
581
582 if (x->aalg) {
583 struct xfrm_algo_desc *aalg_desc;
584
585 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
586 p += (x->aalg->alg_key_len + 7) / 8;
587
588 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
589 BUG_ON(!aalg_desc);
590
591 err = -EINVAL;
592 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
593 crypto_aead_authsize(aead)) {
594 pr_info("ESP: %s digestsize %u != %hu\n",
595 x->aalg->alg_name,
596 crypto_aead_authsize(aead),
597 aalg_desc->uinfo.auth.icv_fullbits / 8);
598 goto free_key;
599 }
600
601 err = crypto_aead_setauthsize(
602 aead, x->aalg->alg_trunc_len / 8);
603 if (err)
604 goto free_key;
605 }
606
607 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
608 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
609
610 err = crypto_aead_setkey(aead, key, keylen);
611
612free_key:
613 kfree(key);
614
615error:
616 return err;
617}
618
619static int esp6_init_state(struct xfrm_state *x)
620{
621 struct crypto_aead *aead;
622 u32 align;
623 int err;
624
625 if (x->encap)
626 return -EINVAL;
627
628 x->data = NULL;
629
630 if (x->aead)
631 err = esp_init_aead(x);
632 else
633 err = esp_init_authenc(x);
634
635 if (err)
636 goto error;
637
638 aead = x->data;
639
640 x->props.header_len = sizeof(struct ip_esp_hdr) +
641 crypto_aead_ivsize(aead);
642 switch (x->props.mode) {
643 case XFRM_MODE_BEET:
644 if (x->sel.family != AF_INET6)
645 x->props.header_len += IPV4_BEET_PHMAXLEN +
646 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
647 break;
648 case XFRM_MODE_TRANSPORT:
649 break;
650 case XFRM_MODE_TUNNEL:
651 x->props.header_len += sizeof(struct ipv6hdr);
652 break;
653 default:
654 goto error;
655 }
656
657 align = ALIGN(crypto_aead_blocksize(aead), 4);
658 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
659
660error:
661 return err;
662}
663
664static int esp6_rcv_cb(struct sk_buff *skb, int err)
665{
666 return 0;
667}
668
669static const struct xfrm_type esp6_type = {
670 .description = "ESP6",
671 .owner = THIS_MODULE,
672 .proto = IPPROTO_ESP,
673 .flags = XFRM_TYPE_REPLAY_PROT,
674 .init_state = esp6_init_state,
675 .destructor = esp6_destroy,
676 .get_mtu = esp6_get_mtu,
677 .input = esp6_input,
678 .output = esp6_output,
679 .hdr_offset = xfrm6_find_1stfragopt,
680};
681
682static struct xfrm6_protocol esp6_protocol = {
683 .handler = xfrm6_rcv,
684 .cb_handler = esp6_rcv_cb,
685 .err_handler = esp6_err,
686 .priority = 0,
687};
688
689static int __init esp6_init(void)
690{
691 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
692 pr_info("%s: can't add xfrm type\n", __func__);
693 return -EAGAIN;
694 }
695 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
696 pr_info("%s: can't add protocol\n", __func__);
697 xfrm_unregister_type(&esp6_type, AF_INET6);
698 return -EAGAIN;
699 }
700
701 return 0;
702}
703
704static void __exit esp6_fini(void)
705{
706 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
707 pr_info("%s: can't remove protocol\n", __func__);
708 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
709 pr_info("%s: can't remove xfrm type\n", __func__);
710}
711
712module_init(esp6_init);
713module_exit(esp6_fini);
714
715MODULE_LICENSE("GPL");
716MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
1/*
2 * Copyright (C)2002 USAGI/WIDE Project
3 *
4 * 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.
8 *
9 * 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.
13 *
14 * 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 *
20 * Mitsuru KANDA @USAGI : IPv6 Support
21 * Kazunori MIYAZAWA @USAGI :
22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
23 *
24 * This file is derived from net/ipv4/esp.c
25 */
26
27#define pr_fmt(fmt) "IPv6: " fmt
28
29#include <crypto/aead.h>
30#include <crypto/authenc.h>
31#include <linux/err.h>
32#include <linux/module.h>
33#include <net/ip.h>
34#include <net/xfrm.h>
35#include <net/esp.h>
36#include <linux/scatterlist.h>
37#include <linux/kernel.h>
38#include <linux/pfkeyv2.h>
39#include <linux/random.h>
40#include <linux/slab.h>
41#include <linux/spinlock.h>
42#include <net/icmp.h>
43#include <net/ipv6.h>
44#include <net/protocol.h>
45#include <linux/icmpv6.h>
46
47struct esp_skb_cb {
48 struct xfrm_skb_cb xfrm;
49 void *tmp;
50};
51
52#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
53
54static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
55
56/*
57 * Allocate an AEAD request structure with extra space for SG and IV.
58 *
59 * For alignment considerations the upper 32 bits of the sequence number are
60 * placed at the front, if present. Followed by the IV, the request and finally
61 * the SG list.
62 *
63 * TODO: Use spare space in skb for this where possible.
64 */
65static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
66{
67 unsigned int len;
68
69 len = seqihlen;
70
71 len += crypto_aead_ivsize(aead);
72
73 if (len) {
74 len += crypto_aead_alignmask(aead) &
75 ~(crypto_tfm_ctx_alignment() - 1);
76 len = ALIGN(len, crypto_tfm_ctx_alignment());
77 }
78
79 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
80 len = ALIGN(len, __alignof__(struct scatterlist));
81
82 len += sizeof(struct scatterlist) * nfrags;
83
84 return kmalloc(len, GFP_ATOMIC);
85}
86
87static inline __be32 *esp_tmp_seqhi(void *tmp)
88{
89 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
90}
91
92static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
93{
94 return crypto_aead_ivsize(aead) ?
95 PTR_ALIGN((u8 *)tmp + seqhilen,
96 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
97}
98
99static inline struct aead_givcrypt_request *esp_tmp_givreq(
100 struct crypto_aead *aead, u8 *iv)
101{
102 struct aead_givcrypt_request *req;
103
104 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
105 crypto_tfm_ctx_alignment());
106 aead_givcrypt_set_tfm(req, aead);
107 return req;
108}
109
110static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
111{
112 struct aead_request *req;
113
114 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
115 crypto_tfm_ctx_alignment());
116 aead_request_set_tfm(req, aead);
117 return req;
118}
119
120static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
121 struct aead_request *req)
122{
123 return (void *)ALIGN((unsigned long)(req + 1) +
124 crypto_aead_reqsize(aead),
125 __alignof__(struct scatterlist));
126}
127
128static inline struct scatterlist *esp_givreq_sg(
129 struct crypto_aead *aead, struct aead_givcrypt_request *req)
130{
131 return (void *)ALIGN((unsigned long)(req + 1) +
132 crypto_aead_reqsize(aead),
133 __alignof__(struct scatterlist));
134}
135
136static void esp_output_done(struct crypto_async_request *base, int err)
137{
138 struct sk_buff *skb = base->data;
139
140 kfree(ESP_SKB_CB(skb)->tmp);
141 xfrm_output_resume(skb, err);
142}
143
144static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
145{
146 int err;
147 struct ip_esp_hdr *esph;
148 struct crypto_aead *aead;
149 struct aead_givcrypt_request *req;
150 struct scatterlist *sg;
151 struct scatterlist *asg;
152 struct sk_buff *trailer;
153 void *tmp;
154 int blksize;
155 int clen;
156 int alen;
157 int plen;
158 int tfclen;
159 int nfrags;
160 int assoclen;
161 int sglists;
162 int seqhilen;
163 u8 *iv;
164 u8 *tail;
165 __be32 *seqhi;
166 struct esp_data *esp = x->data;
167
168 /* skb is pure payload to encrypt */
169 err = -ENOMEM;
170
171 aead = esp->aead;
172 alen = crypto_aead_authsize(aead);
173
174 tfclen = 0;
175 if (x->tfcpad) {
176 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
177 u32 padto;
178
179 padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
180 if (skb->len < padto)
181 tfclen = padto - skb->len;
182 }
183 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
184 clen = ALIGN(skb->len + 2 + tfclen, blksize);
185 if (esp->padlen)
186 clen = ALIGN(clen, esp->padlen);
187 plen = clen - skb->len - tfclen;
188
189 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
190 if (err < 0)
191 goto error;
192 nfrags = err;
193
194 assoclen = sizeof(*esph);
195 sglists = 1;
196 seqhilen = 0;
197
198 if (x->props.flags & XFRM_STATE_ESN) {
199 sglists += 2;
200 seqhilen += sizeof(__be32);
201 assoclen += seqhilen;
202 }
203
204 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
205 if (!tmp)
206 goto error;
207
208 seqhi = esp_tmp_seqhi(tmp);
209 iv = esp_tmp_iv(aead, tmp, seqhilen);
210 req = esp_tmp_givreq(aead, iv);
211 asg = esp_givreq_sg(aead, req);
212 sg = asg + sglists;
213
214 /* Fill padding... */
215 tail = skb_tail_pointer(trailer);
216 if (tfclen) {
217 memset(tail, 0, tfclen);
218 tail += tfclen;
219 }
220 do {
221 int i;
222 for (i = 0; i < plen - 2; i++)
223 tail[i] = i + 1;
224 } while (0);
225 tail[plen - 2] = plen - 2;
226 tail[plen - 1] = *skb_mac_header(skb);
227 pskb_put(skb, trailer, clen - skb->len + alen);
228
229 skb_push(skb, -skb_network_offset(skb));
230 esph = ip_esp_hdr(skb);
231 *skb_mac_header(skb) = IPPROTO_ESP;
232
233 esph->spi = x->id.spi;
234 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
235
236 sg_init_table(sg, nfrags);
237 skb_to_sgvec(skb, sg,
238 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
239 clen + alen);
240
241 if ((x->props.flags & XFRM_STATE_ESN)) {
242 sg_init_table(asg, 3);
243 sg_set_buf(asg, &esph->spi, sizeof(__be32));
244 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
245 sg_set_buf(asg + 1, seqhi, seqhilen);
246 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
247 } else
248 sg_init_one(asg, esph, sizeof(*esph));
249
250 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
251 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
252 aead_givcrypt_set_assoc(req, asg, assoclen);
253 aead_givcrypt_set_giv(req, esph->enc_data,
254 XFRM_SKB_CB(skb)->seq.output.low);
255
256 ESP_SKB_CB(skb)->tmp = tmp;
257 err = crypto_aead_givencrypt(req);
258 if (err == -EINPROGRESS)
259 goto error;
260
261 if (err == -EBUSY)
262 err = NET_XMIT_DROP;
263
264 kfree(tmp);
265
266error:
267 return err;
268}
269
270static int esp_input_done2(struct sk_buff *skb, int err)
271{
272 struct xfrm_state *x = xfrm_input_state(skb);
273 struct esp_data *esp = x->data;
274 struct crypto_aead *aead = esp->aead;
275 int alen = crypto_aead_authsize(aead);
276 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
277 int elen = skb->len - hlen;
278 int hdr_len = skb_network_header_len(skb);
279 int padlen;
280 u8 nexthdr[2];
281
282 kfree(ESP_SKB_CB(skb)->tmp);
283
284 if (unlikely(err))
285 goto out;
286
287 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
288 BUG();
289
290 err = -EINVAL;
291 padlen = nexthdr[0];
292 if (padlen + 2 + alen >= elen) {
293 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
294 "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
295 goto out;
296 }
297
298 /* ... check padding bits here. Silly. :-) */
299
300 pskb_trim(skb, skb->len - alen - padlen - 2);
301 __skb_pull(skb, hlen);
302 skb_set_transport_header(skb, -hdr_len);
303
304 err = nexthdr[1];
305
306 /* RFC4303: Drop dummy packets without any error */
307 if (err == IPPROTO_NONE)
308 err = -EINVAL;
309
310out:
311 return err;
312}
313
314static void esp_input_done(struct crypto_async_request *base, int err)
315{
316 struct sk_buff *skb = base->data;
317
318 xfrm_input_resume(skb, esp_input_done2(skb, err));
319}
320
321static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
322{
323 struct ip_esp_hdr *esph;
324 struct esp_data *esp = x->data;
325 struct crypto_aead *aead = esp->aead;
326 struct aead_request *req;
327 struct sk_buff *trailer;
328 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
329 int nfrags;
330 int assoclen;
331 int sglists;
332 int seqhilen;
333 int ret = 0;
334 void *tmp;
335 __be32 *seqhi;
336 u8 *iv;
337 struct scatterlist *sg;
338 struct scatterlist *asg;
339
340 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
341 ret = -EINVAL;
342 goto out;
343 }
344
345 if (elen <= 0) {
346 ret = -EINVAL;
347 goto out;
348 }
349
350 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
351 ret = -EINVAL;
352 goto out;
353 }
354
355 ret = -ENOMEM;
356
357 assoclen = sizeof(*esph);
358 sglists = 1;
359 seqhilen = 0;
360
361 if (x->props.flags & XFRM_STATE_ESN) {
362 sglists += 2;
363 seqhilen += sizeof(__be32);
364 assoclen += seqhilen;
365 }
366
367 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
368 if (!tmp)
369 goto out;
370
371 ESP_SKB_CB(skb)->tmp = tmp;
372 seqhi = esp_tmp_seqhi(tmp);
373 iv = esp_tmp_iv(aead, tmp, seqhilen);
374 req = esp_tmp_req(aead, iv);
375 asg = esp_req_sg(aead, req);
376 sg = asg + sglists;
377
378 skb->ip_summed = CHECKSUM_NONE;
379
380 esph = (struct ip_esp_hdr *)skb->data;
381
382 /* Get ivec. This can be wrong, check against another impls. */
383 iv = esph->enc_data;
384
385 sg_init_table(sg, nfrags);
386 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
387
388 if ((x->props.flags & XFRM_STATE_ESN)) {
389 sg_init_table(asg, 3);
390 sg_set_buf(asg, &esph->spi, sizeof(__be32));
391 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
392 sg_set_buf(asg + 1, seqhi, seqhilen);
393 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
394 } else
395 sg_init_one(asg, esph, sizeof(*esph));
396
397 aead_request_set_callback(req, 0, esp_input_done, skb);
398 aead_request_set_crypt(req, sg, sg, elen, iv);
399 aead_request_set_assoc(req, asg, assoclen);
400
401 ret = crypto_aead_decrypt(req);
402 if (ret == -EINPROGRESS)
403 goto out;
404
405 ret = esp_input_done2(skb, ret);
406
407out:
408 return ret;
409}
410
411static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
412{
413 struct esp_data *esp = x->data;
414 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
415 u32 align = max_t(u32, blksize, esp->padlen);
416 unsigned int net_adj;
417
418 if (x->props.mode != XFRM_MODE_TUNNEL)
419 net_adj = sizeof(struct ipv6hdr);
420 else
421 net_adj = 0;
422
423 return ((mtu - x->props.header_len - crypto_aead_authsize(esp->aead) -
424 net_adj) & ~(align - 1)) + (net_adj - 2);
425}
426
427static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
428 u8 type, u8 code, int offset, __be32 info)
429{
430 struct net *net = dev_net(skb->dev);
431 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
432 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
433 struct xfrm_state *x;
434
435 if (type != ICMPV6_DEST_UNREACH &&
436 type != ICMPV6_PKT_TOOBIG)
437 return;
438
439 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
440 esph->spi, IPPROTO_ESP, AF_INET6);
441 if (!x)
442 return;
443 pr_debug("pmtu discovery on SA ESP/%08x/%pI6\n",
444 ntohl(esph->spi), &iph->daddr);
445 xfrm_state_put(x);
446}
447
448static void esp6_destroy(struct xfrm_state *x)
449{
450 struct esp_data *esp = x->data;
451
452 if (!esp)
453 return;
454
455 crypto_free_aead(esp->aead);
456 kfree(esp);
457}
458
459static int esp_init_aead(struct xfrm_state *x)
460{
461 struct esp_data *esp = x->data;
462 struct crypto_aead *aead;
463 int err;
464
465 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
466 err = PTR_ERR(aead);
467 if (IS_ERR(aead))
468 goto error;
469
470 esp->aead = aead;
471
472 err = crypto_aead_setkey(aead, x->aead->alg_key,
473 (x->aead->alg_key_len + 7) / 8);
474 if (err)
475 goto error;
476
477 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
478 if (err)
479 goto error;
480
481error:
482 return err;
483}
484
485static int esp_init_authenc(struct xfrm_state *x)
486{
487 struct esp_data *esp = x->data;
488 struct crypto_aead *aead;
489 struct crypto_authenc_key_param *param;
490 struct rtattr *rta;
491 char *key;
492 char *p;
493 char authenc_name[CRYPTO_MAX_ALG_NAME];
494 unsigned int keylen;
495 int err;
496
497 err = -EINVAL;
498 if (x->ealg == NULL)
499 goto error;
500
501 err = -ENAMETOOLONG;
502
503 if ((x->props.flags & XFRM_STATE_ESN)) {
504 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
505 "authencesn(%s,%s)",
506 x->aalg ? x->aalg->alg_name : "digest_null",
507 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
508 goto error;
509 } else {
510 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
511 "authenc(%s,%s)",
512 x->aalg ? x->aalg->alg_name : "digest_null",
513 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
514 goto error;
515 }
516
517 aead = crypto_alloc_aead(authenc_name, 0, 0);
518 err = PTR_ERR(aead);
519 if (IS_ERR(aead))
520 goto error;
521
522 esp->aead = aead;
523
524 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
525 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
526 err = -ENOMEM;
527 key = kmalloc(keylen, GFP_KERNEL);
528 if (!key)
529 goto error;
530
531 p = key;
532 rta = (void *)p;
533 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
534 rta->rta_len = RTA_LENGTH(sizeof(*param));
535 param = RTA_DATA(rta);
536 p += RTA_SPACE(sizeof(*param));
537
538 if (x->aalg) {
539 struct xfrm_algo_desc *aalg_desc;
540
541 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
542 p += (x->aalg->alg_key_len + 7) / 8;
543
544 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
545 BUG_ON(!aalg_desc);
546
547 err = -EINVAL;
548 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
549 crypto_aead_authsize(aead)) {
550 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
551 x->aalg->alg_name,
552 crypto_aead_authsize(aead),
553 aalg_desc->uinfo.auth.icv_fullbits/8);
554 goto free_key;
555 }
556
557 err = crypto_aead_setauthsize(
558 aead, x->aalg->alg_trunc_len / 8);
559 if (err)
560 goto free_key;
561 }
562
563 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
564 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
565
566 err = crypto_aead_setkey(aead, key, keylen);
567
568free_key:
569 kfree(key);
570
571error:
572 return err;
573}
574
575static int esp6_init_state(struct xfrm_state *x)
576{
577 struct esp_data *esp;
578 struct crypto_aead *aead;
579 u32 align;
580 int err;
581
582 if (x->encap)
583 return -EINVAL;
584
585 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
586 if (esp == NULL)
587 return -ENOMEM;
588
589 x->data = esp;
590
591 if (x->aead)
592 err = esp_init_aead(x);
593 else
594 err = esp_init_authenc(x);
595
596 if (err)
597 goto error;
598
599 aead = esp->aead;
600
601 esp->padlen = 0;
602
603 x->props.header_len = sizeof(struct ip_esp_hdr) +
604 crypto_aead_ivsize(aead);
605 switch (x->props.mode) {
606 case XFRM_MODE_BEET:
607 if (x->sel.family != AF_INET6)
608 x->props.header_len += IPV4_BEET_PHMAXLEN +
609 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
610 break;
611 case XFRM_MODE_TRANSPORT:
612 break;
613 case XFRM_MODE_TUNNEL:
614 x->props.header_len += sizeof(struct ipv6hdr);
615 break;
616 default:
617 goto error;
618 }
619
620 align = ALIGN(crypto_aead_blocksize(aead), 4);
621 if (esp->padlen)
622 align = max_t(u32, align, esp->padlen);
623 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
624
625error:
626 return err;
627}
628
629static const struct xfrm_type esp6_type =
630{
631 .description = "ESP6",
632 .owner = THIS_MODULE,
633 .proto = IPPROTO_ESP,
634 .flags = XFRM_TYPE_REPLAY_PROT,
635 .init_state = esp6_init_state,
636 .destructor = esp6_destroy,
637 .get_mtu = esp6_get_mtu,
638 .input = esp6_input,
639 .output = esp6_output,
640 .hdr_offset = xfrm6_find_1stfragopt,
641};
642
643static const struct inet6_protocol esp6_protocol = {
644 .handler = xfrm6_rcv,
645 .err_handler = esp6_err,
646 .flags = INET6_PROTO_NOPOLICY,
647};
648
649static int __init esp6_init(void)
650{
651 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
652 pr_info("%s: can't add xfrm type\n", __func__);
653 return -EAGAIN;
654 }
655 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
656 pr_info("%s: can't add protocol\n", __func__);
657 xfrm_unregister_type(&esp6_type, AF_INET6);
658 return -EAGAIN;
659 }
660
661 return 0;
662}
663
664static void __exit esp6_fini(void)
665{
666 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
667 pr_info("%s: can't remove protocol\n", __func__);
668 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
669 pr_info("%s: can't remove xfrm type\n", __func__);
670}
671
672module_init(esp6_init);
673module_exit(esp6_fini);
674
675MODULE_LICENSE("GPL");
676MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);