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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// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C)2002 USAGI/WIDE Project
4 *
5 * Authors
6 *
7 * Mitsuru KANDA @USAGI : IPv6 Support
8 * Kazunori MIYAZAWA @USAGI :
9 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
10 *
11 * This file is derived from net/ipv4/esp.c
12 */
13
14#define pr_fmt(fmt) "IPv6: " fmt
15
16#include <crypto/aead.h>
17#include <crypto/authenc.h>
18#include <linux/err.h>
19#include <linux/module.h>
20#include <net/ip.h>
21#include <net/xfrm.h>
22#include <net/esp.h>
23#include <linux/scatterlist.h>
24#include <linux/kernel.h>
25#include <linux/pfkeyv2.h>
26#include <linux/random.h>
27#include <linux/slab.h>
28#include <linux/spinlock.h>
29#include <net/ip6_checksum.h>
30#include <net/ip6_route.h>
31#include <net/icmp.h>
32#include <net/ipv6.h>
33#include <net/protocol.h>
34#include <net/udp.h>
35#include <linux/icmpv6.h>
36#include <net/tcp.h>
37#include <net/espintcp.h>
38#include <net/inet6_hashtables.h>
39#include <linux/skbuff_ref.h>
40
41#include <linux/highmem.h>
42
43struct esp_skb_cb {
44 struct xfrm_skb_cb xfrm;
45 void *tmp;
46};
47
48struct esp_output_extra {
49 __be32 seqhi;
50 u32 esphoff;
51};
52
53#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
54
55/*
56 * Allocate an AEAD request structure with extra space for SG and IV.
57 *
58 * For alignment considerations the upper 32 bits of the sequence number are
59 * placed at the front, if present. Followed by the IV, the request and finally
60 * the SG list.
61 *
62 * TODO: Use spare space in skb for this where possible.
63 */
64static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
65{
66 unsigned int len;
67
68 len = seqihlen;
69
70 len += crypto_aead_ivsize(aead);
71
72 if (len) {
73 len += crypto_aead_alignmask(aead) &
74 ~(crypto_tfm_ctx_alignment() - 1);
75 len = ALIGN(len, crypto_tfm_ctx_alignment());
76 }
77
78 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
79 len = ALIGN(len, __alignof__(struct scatterlist));
80
81 len += sizeof(struct scatterlist) * nfrags;
82
83 return kmalloc(len, GFP_ATOMIC);
84}
85
86static inline void *esp_tmp_extra(void *tmp)
87{
88 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
89}
90
91static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
92{
93 return crypto_aead_ivsize(aead) ?
94 PTR_ALIGN((u8 *)tmp + seqhilen,
95 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
96}
97
98static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
99{
100 struct aead_request *req;
101
102 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
103 crypto_tfm_ctx_alignment());
104 aead_request_set_tfm(req, aead);
105 return req;
106}
107
108static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
109 struct aead_request *req)
110{
111 return (void *)ALIGN((unsigned long)(req + 1) +
112 crypto_aead_reqsize(aead),
113 __alignof__(struct scatterlist));
114}
115
116static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
117{
118 struct crypto_aead *aead = x->data;
119 int extralen = 0;
120 u8 *iv;
121 struct aead_request *req;
122 struct scatterlist *sg;
123
124 if (x->props.flags & XFRM_STATE_ESN)
125 extralen += sizeof(struct esp_output_extra);
126
127 iv = esp_tmp_iv(aead, tmp, extralen);
128 req = esp_tmp_req(aead, iv);
129
130 /* Unref skb_frag_pages in the src scatterlist if necessary.
131 * Skip the first sg which comes from skb->data.
132 */
133 if (req->src != req->dst)
134 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
135 skb_page_unref(page_to_netmem(sg_page(sg)),
136 skb->pp_recycle);
137}
138
139#ifdef CONFIG_INET6_ESPINTCP
140struct esp_tcp_sk {
141 struct sock *sk;
142 struct rcu_head rcu;
143};
144
145static void esp_free_tcp_sk(struct rcu_head *head)
146{
147 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
148
149 sock_put(esk->sk);
150 kfree(esk);
151}
152
153static struct sock *esp6_find_tcp_sk(struct xfrm_state *x)
154{
155 struct xfrm_encap_tmpl *encap = x->encap;
156 struct net *net = xs_net(x);
157 struct esp_tcp_sk *esk;
158 __be16 sport, dport;
159 struct sock *nsk;
160 struct sock *sk;
161
162 sk = rcu_dereference(x->encap_sk);
163 if (sk && sk->sk_state == TCP_ESTABLISHED)
164 return sk;
165
166 spin_lock_bh(&x->lock);
167 sport = encap->encap_sport;
168 dport = encap->encap_dport;
169 nsk = rcu_dereference_protected(x->encap_sk,
170 lockdep_is_held(&x->lock));
171 if (sk && sk == nsk) {
172 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
173 if (!esk) {
174 spin_unlock_bh(&x->lock);
175 return ERR_PTR(-ENOMEM);
176 }
177 RCU_INIT_POINTER(x->encap_sk, NULL);
178 esk->sk = sk;
179 call_rcu(&esk->rcu, esp_free_tcp_sk);
180 }
181 spin_unlock_bh(&x->lock);
182
183 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, &x->id.daddr.in6,
184 dport, &x->props.saddr.in6, ntohs(sport), 0, 0);
185 if (!sk)
186 return ERR_PTR(-ENOENT);
187
188 if (!tcp_is_ulp_esp(sk)) {
189 sock_put(sk);
190 return ERR_PTR(-EINVAL);
191 }
192
193 spin_lock_bh(&x->lock);
194 nsk = rcu_dereference_protected(x->encap_sk,
195 lockdep_is_held(&x->lock));
196 if (encap->encap_sport != sport ||
197 encap->encap_dport != dport) {
198 sock_put(sk);
199 sk = nsk ?: ERR_PTR(-EREMCHG);
200 } else if (sk == nsk) {
201 sock_put(sk);
202 } else {
203 rcu_assign_pointer(x->encap_sk, sk);
204 }
205 spin_unlock_bh(&x->lock);
206
207 return sk;
208}
209
210static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
211{
212 struct sock *sk;
213 int err;
214
215 rcu_read_lock();
216
217 sk = esp6_find_tcp_sk(x);
218 err = PTR_ERR_OR_ZERO(sk);
219 if (err)
220 goto out;
221
222 bh_lock_sock(sk);
223 if (sock_owned_by_user(sk))
224 err = espintcp_queue_out(sk, skb);
225 else
226 err = espintcp_push_skb(sk, skb);
227 bh_unlock_sock(sk);
228
229out:
230 rcu_read_unlock();
231 return err;
232}
233
234static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
235 struct sk_buff *skb)
236{
237 struct dst_entry *dst = skb_dst(skb);
238 struct xfrm_state *x = dst->xfrm;
239
240 return esp_output_tcp_finish(x, skb);
241}
242
243static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
244{
245 int err;
246
247 local_bh_disable();
248 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
249 local_bh_enable();
250
251 /* EINPROGRESS just happens to do the right thing. It
252 * actually means that the skb has been consumed and
253 * isn't coming back.
254 */
255 return err ?: -EINPROGRESS;
256}
257#else
258static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
259{
260 WARN_ON(1);
261 return -EOPNOTSUPP;
262}
263#endif
264
265static void esp_output_encap_csum(struct sk_buff *skb)
266{
267 /* UDP encap with IPv6 requires a valid checksum */
268 if (*skb_mac_header(skb) == IPPROTO_UDP) {
269 struct udphdr *uh = udp_hdr(skb);
270 struct ipv6hdr *ip6h = ipv6_hdr(skb);
271 int len = ntohs(uh->len);
272 unsigned int offset = skb_transport_offset(skb);
273 __wsum csum = skb_checksum(skb, offset, skb->len - offset, 0);
274
275 uh->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
276 len, IPPROTO_UDP, csum);
277 if (uh->check == 0)
278 uh->check = CSUM_MANGLED_0;
279 }
280}
281
282static void esp_output_done(void *data, int err)
283{
284 struct sk_buff *skb = data;
285 struct xfrm_offload *xo = xfrm_offload(skb);
286 void *tmp;
287 struct xfrm_state *x;
288
289 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
290 struct sec_path *sp = skb_sec_path(skb);
291
292 x = sp->xvec[sp->len - 1];
293 } else {
294 x = skb_dst(skb)->xfrm;
295 }
296
297 tmp = ESP_SKB_CB(skb)->tmp;
298 esp_ssg_unref(x, tmp, skb);
299 kfree(tmp);
300
301 esp_output_encap_csum(skb);
302
303 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
304 if (err) {
305 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
306 kfree_skb(skb);
307 return;
308 }
309
310 skb_push(skb, skb->data - skb_mac_header(skb));
311 secpath_reset(skb);
312 xfrm_dev_resume(skb);
313 } else {
314 if (!err &&
315 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
316 esp_output_tail_tcp(x, skb);
317 else
318 xfrm_output_resume(skb->sk, skb, err);
319 }
320}
321
322/* Move ESP header back into place. */
323static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
324{
325 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
326 void *tmp = ESP_SKB_CB(skb)->tmp;
327 __be32 *seqhi = esp_tmp_extra(tmp);
328
329 esph->seq_no = esph->spi;
330 esph->spi = *seqhi;
331}
332
333static void esp_output_restore_header(struct sk_buff *skb)
334{
335 void *tmp = ESP_SKB_CB(skb)->tmp;
336 struct esp_output_extra *extra = esp_tmp_extra(tmp);
337
338 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
339 sizeof(__be32));
340}
341
342static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
343 struct xfrm_state *x,
344 struct ip_esp_hdr *esph,
345 struct esp_output_extra *extra)
346{
347 /* For ESN we move the header forward by 4 bytes to
348 * accommodate the high bits. We will move it back after
349 * encryption.
350 */
351 if ((x->props.flags & XFRM_STATE_ESN)) {
352 __u32 seqhi;
353 struct xfrm_offload *xo = xfrm_offload(skb);
354
355 if (xo)
356 seqhi = xo->seq.hi;
357 else
358 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
359
360 extra->esphoff = (unsigned char *)esph -
361 skb_transport_header(skb);
362 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
363 extra->seqhi = esph->spi;
364 esph->seq_no = htonl(seqhi);
365 }
366
367 esph->spi = x->id.spi;
368
369 return esph;
370}
371
372static void esp_output_done_esn(void *data, int err)
373{
374 struct sk_buff *skb = data;
375
376 esp_output_restore_header(skb);
377 esp_output_done(data, err);
378}
379
380static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb,
381 int encap_type,
382 struct esp_info *esp,
383 __be16 sport,
384 __be16 dport)
385{
386 struct udphdr *uh;
387 unsigned int len;
388
389 len = skb->len + esp->tailen - skb_transport_offset(skb);
390 if (len > U16_MAX)
391 return ERR_PTR(-EMSGSIZE);
392
393 uh = (struct udphdr *)esp->esph;
394 uh->source = sport;
395 uh->dest = dport;
396 uh->len = htons(len);
397 uh->check = 0;
398
399 *skb_mac_header(skb) = IPPROTO_UDP;
400
401 return (struct ip_esp_hdr *)(uh + 1);
402}
403
404#ifdef CONFIG_INET6_ESPINTCP
405static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
406 struct sk_buff *skb,
407 struct esp_info *esp)
408{
409 __be16 *lenp = (void *)esp->esph;
410 struct ip_esp_hdr *esph;
411 unsigned int len;
412 struct sock *sk;
413
414 len = skb->len + esp->tailen - skb_transport_offset(skb);
415 if (len > IP_MAX_MTU)
416 return ERR_PTR(-EMSGSIZE);
417
418 rcu_read_lock();
419 sk = esp6_find_tcp_sk(x);
420 rcu_read_unlock();
421
422 if (IS_ERR(sk))
423 return ERR_CAST(sk);
424
425 *lenp = htons(len);
426 esph = (struct ip_esp_hdr *)(lenp + 1);
427
428 return esph;
429}
430#else
431static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
432 struct sk_buff *skb,
433 struct esp_info *esp)
434{
435 return ERR_PTR(-EOPNOTSUPP);
436}
437#endif
438
439static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb,
440 struct esp_info *esp)
441{
442 struct xfrm_encap_tmpl *encap = x->encap;
443 struct ip_esp_hdr *esph;
444 __be16 sport, dport;
445 int encap_type;
446
447 spin_lock_bh(&x->lock);
448 sport = encap->encap_sport;
449 dport = encap->encap_dport;
450 encap_type = encap->encap_type;
451 spin_unlock_bh(&x->lock);
452
453 switch (encap_type) {
454 default:
455 case UDP_ENCAP_ESPINUDP:
456 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport);
457 break;
458 case TCP_ENCAP_ESPINTCP:
459 esph = esp6_output_tcp_encap(x, skb, esp);
460 break;
461 }
462
463 if (IS_ERR(esph))
464 return PTR_ERR(esph);
465
466 esp->esph = esph;
467
468 return 0;
469}
470
471int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
472{
473 u8 *tail;
474 int nfrags;
475 int esph_offset;
476 struct page *page;
477 struct sk_buff *trailer;
478 int tailen = esp->tailen;
479
480 if (x->encap) {
481 int err = esp6_output_encap(x, skb, esp);
482
483 if (err < 0)
484 return err;
485 }
486
487 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
488 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
489 goto cow;
490
491 if (!skb_cloned(skb)) {
492 if (tailen <= skb_tailroom(skb)) {
493 nfrags = 1;
494 trailer = skb;
495 tail = skb_tail_pointer(trailer);
496
497 goto skip_cow;
498 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
499 && !skb_has_frag_list(skb)) {
500 int allocsize;
501 struct sock *sk = skb->sk;
502 struct page_frag *pfrag = &x->xfrag;
503
504 esp->inplace = false;
505
506 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
507
508 spin_lock_bh(&x->lock);
509
510 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
511 spin_unlock_bh(&x->lock);
512 goto cow;
513 }
514
515 page = pfrag->page;
516 get_page(page);
517
518 tail = page_address(page) + pfrag->offset;
519
520 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
521
522 nfrags = skb_shinfo(skb)->nr_frags;
523
524 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
525 tailen);
526 skb_shinfo(skb)->nr_frags = ++nfrags;
527
528 pfrag->offset = pfrag->offset + allocsize;
529
530 spin_unlock_bh(&x->lock);
531
532 nfrags++;
533
534 skb->len += tailen;
535 skb->data_len += tailen;
536 skb->truesize += tailen;
537 if (sk && sk_fullsock(sk))
538 refcount_add(tailen, &sk->sk_wmem_alloc);
539
540 goto out;
541 }
542 }
543
544cow:
545 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
546
547 nfrags = skb_cow_data(skb, tailen, &trailer);
548 if (nfrags < 0)
549 goto out;
550 tail = skb_tail_pointer(trailer);
551 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
552
553skip_cow:
554 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
555 pskb_put(skb, trailer, tailen);
556
557out:
558 return nfrags;
559}
560EXPORT_SYMBOL_GPL(esp6_output_head);
561
562int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
563{
564 u8 *iv;
565 int alen;
566 void *tmp;
567 int ivlen;
568 int assoclen;
569 int extralen;
570 struct page *page;
571 struct ip_esp_hdr *esph;
572 struct aead_request *req;
573 struct crypto_aead *aead;
574 struct scatterlist *sg, *dsg;
575 struct esp_output_extra *extra;
576 int err = -ENOMEM;
577
578 assoclen = sizeof(struct ip_esp_hdr);
579 extralen = 0;
580
581 if (x->props.flags & XFRM_STATE_ESN) {
582 extralen += sizeof(*extra);
583 assoclen += sizeof(__be32);
584 }
585
586 aead = x->data;
587 alen = crypto_aead_authsize(aead);
588 ivlen = crypto_aead_ivsize(aead);
589
590 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
591 if (!tmp)
592 goto error;
593
594 extra = esp_tmp_extra(tmp);
595 iv = esp_tmp_iv(aead, tmp, extralen);
596 req = esp_tmp_req(aead, iv);
597 sg = esp_req_sg(aead, req);
598
599 if (esp->inplace)
600 dsg = sg;
601 else
602 dsg = &sg[esp->nfrags];
603
604 esph = esp_output_set_esn(skb, x, esp->esph, extra);
605 esp->esph = esph;
606
607 sg_init_table(sg, esp->nfrags);
608 err = skb_to_sgvec(skb, sg,
609 (unsigned char *)esph - skb->data,
610 assoclen + ivlen + esp->clen + alen);
611 if (unlikely(err < 0))
612 goto error_free;
613
614 if (!esp->inplace) {
615 int allocsize;
616 struct page_frag *pfrag = &x->xfrag;
617
618 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
619
620 spin_lock_bh(&x->lock);
621 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
622 spin_unlock_bh(&x->lock);
623 goto error_free;
624 }
625
626 skb_shinfo(skb)->nr_frags = 1;
627
628 page = pfrag->page;
629 get_page(page);
630 /* replace page frags in skb with new page */
631 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
632 pfrag->offset = pfrag->offset + allocsize;
633 spin_unlock_bh(&x->lock);
634
635 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
636 err = skb_to_sgvec(skb, dsg,
637 (unsigned char *)esph - skb->data,
638 assoclen + ivlen + esp->clen + alen);
639 if (unlikely(err < 0))
640 goto error_free;
641 }
642
643 if ((x->props.flags & XFRM_STATE_ESN))
644 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
645 else
646 aead_request_set_callback(req, 0, esp_output_done, skb);
647
648 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
649 aead_request_set_ad(req, assoclen);
650
651 memset(iv, 0, ivlen);
652 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
653 min(ivlen, 8));
654
655 ESP_SKB_CB(skb)->tmp = tmp;
656 err = crypto_aead_encrypt(req);
657
658 switch (err) {
659 case -EINPROGRESS:
660 goto error;
661
662 case -ENOSPC:
663 err = NET_XMIT_DROP;
664 break;
665
666 case 0:
667 if ((x->props.flags & XFRM_STATE_ESN))
668 esp_output_restore_header(skb);
669 esp_output_encap_csum(skb);
670 }
671
672 if (sg != dsg)
673 esp_ssg_unref(x, tmp, skb);
674
675 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
676 err = esp_output_tail_tcp(x, skb);
677
678error_free:
679 kfree(tmp);
680error:
681 return err;
682}
683EXPORT_SYMBOL_GPL(esp6_output_tail);
684
685static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
686{
687 int alen;
688 int blksize;
689 struct ip_esp_hdr *esph;
690 struct crypto_aead *aead;
691 struct esp_info esp;
692
693 esp.inplace = true;
694
695 esp.proto = *skb_mac_header(skb);
696 *skb_mac_header(skb) = IPPROTO_ESP;
697
698 /* skb is pure payload to encrypt */
699
700 aead = x->data;
701 alen = crypto_aead_authsize(aead);
702
703 esp.tfclen = 0;
704 if (x->tfcpad) {
705 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
706 u32 padto;
707
708 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
709 if (skb->len < padto)
710 esp.tfclen = padto - skb->len;
711 }
712 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
713 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
714 esp.plen = esp.clen - skb->len - esp.tfclen;
715 esp.tailen = esp.tfclen + esp.plen + alen;
716
717 esp.esph = ip_esp_hdr(skb);
718
719 esp.nfrags = esp6_output_head(x, skb, &esp);
720 if (esp.nfrags < 0)
721 return esp.nfrags;
722
723 esph = esp.esph;
724 esph->spi = x->id.spi;
725
726 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
727 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
728 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
729
730 skb_push(skb, -skb_network_offset(skb));
731
732 return esp6_output_tail(x, skb, &esp);
733}
734
735static inline int esp_remove_trailer(struct sk_buff *skb)
736{
737 struct xfrm_state *x = xfrm_input_state(skb);
738 struct crypto_aead *aead = x->data;
739 int alen, hlen, elen;
740 int padlen, trimlen;
741 __wsum csumdiff;
742 u8 nexthdr[2];
743 int ret;
744
745 alen = crypto_aead_authsize(aead);
746 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
747 elen = skb->len - hlen;
748
749 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2);
750 BUG_ON(ret);
751
752 ret = -EINVAL;
753 padlen = nexthdr[0];
754 if (padlen + 2 + alen >= elen) {
755 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
756 padlen + 2, elen - alen);
757 goto out;
758 }
759
760 trimlen = alen + padlen + 2;
761 if (skb->ip_summed == CHECKSUM_COMPLETE) {
762 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
763 skb->csum = csum_block_sub(skb->csum, csumdiff,
764 skb->len - trimlen);
765 }
766 ret = pskb_trim(skb, skb->len - trimlen);
767 if (unlikely(ret))
768 return ret;
769
770 ret = nexthdr[1];
771
772out:
773 return ret;
774}
775
776int esp6_input_done2(struct sk_buff *skb, int err)
777{
778 struct xfrm_state *x = xfrm_input_state(skb);
779 struct xfrm_offload *xo = xfrm_offload(skb);
780 struct crypto_aead *aead = x->data;
781 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
782 int hdr_len = skb_network_header_len(skb);
783
784 if (!xo || !(xo->flags & CRYPTO_DONE))
785 kfree(ESP_SKB_CB(skb)->tmp);
786
787 if (unlikely(err))
788 goto out;
789
790 err = esp_remove_trailer(skb);
791 if (unlikely(err < 0))
792 goto out;
793
794 if (x->encap) {
795 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
796 int offset = skb_network_offset(skb) + sizeof(*ip6h);
797 struct xfrm_encap_tmpl *encap = x->encap;
798 u8 nexthdr = ip6h->nexthdr;
799 __be16 frag_off, source;
800 struct udphdr *uh;
801 struct tcphdr *th;
802
803 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
804 if (offset == -1) {
805 err = -EINVAL;
806 goto out;
807 }
808
809 uh = (void *)(skb->data + offset);
810 th = (void *)(skb->data + offset);
811 hdr_len += offset;
812
813 switch (x->encap->encap_type) {
814 case TCP_ENCAP_ESPINTCP:
815 source = th->source;
816 break;
817 case UDP_ENCAP_ESPINUDP:
818 source = uh->source;
819 break;
820 default:
821 WARN_ON_ONCE(1);
822 err = -EINVAL;
823 goto out;
824 }
825
826 /*
827 * 1) if the NAT-T peer's IP or port changed then
828 * advertise the change to the keying daemon.
829 * This is an inbound SA, so just compare
830 * SRC ports.
831 */
832 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) ||
833 source != encap->encap_sport) {
834 xfrm_address_t ipaddr;
835
836 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6));
837 km_new_mapping(x, &ipaddr, source);
838
839 /* XXX: perhaps add an extra
840 * policy check here, to see
841 * if we should allow or
842 * reject a packet from a
843 * different source
844 * address/port.
845 */
846 }
847
848 /*
849 * 2) ignore UDP/TCP checksums in case
850 * of NAT-T in Transport Mode, or
851 * perform other post-processing fixes
852 * as per draft-ietf-ipsec-udp-encaps-06,
853 * section 3.1.2
854 */
855 if (x->props.mode == XFRM_MODE_TRANSPORT)
856 skb->ip_summed = CHECKSUM_UNNECESSARY;
857 }
858
859 skb_postpull_rcsum(skb, skb_network_header(skb),
860 skb_network_header_len(skb));
861 skb_pull_rcsum(skb, hlen);
862 if (x->props.mode == XFRM_MODE_TUNNEL)
863 skb_reset_transport_header(skb);
864 else
865 skb_set_transport_header(skb, -hdr_len);
866
867 /* RFC4303: Drop dummy packets without any error */
868 if (err == IPPROTO_NONE)
869 err = -EINVAL;
870
871out:
872 return err;
873}
874EXPORT_SYMBOL_GPL(esp6_input_done2);
875
876static void esp_input_done(void *data, int err)
877{
878 struct sk_buff *skb = data;
879
880 xfrm_input_resume(skb, esp6_input_done2(skb, err));
881}
882
883static void esp_input_restore_header(struct sk_buff *skb)
884{
885 esp_restore_header(skb, 0);
886 __skb_pull(skb, 4);
887}
888
889static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
890{
891 struct xfrm_state *x = xfrm_input_state(skb);
892
893 /* For ESN we move the header forward by 4 bytes to
894 * accommodate the high bits. We will move it back after
895 * decryption.
896 */
897 if ((x->props.flags & XFRM_STATE_ESN)) {
898 struct ip_esp_hdr *esph = skb_push(skb, 4);
899
900 *seqhi = esph->spi;
901 esph->spi = esph->seq_no;
902 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
903 }
904}
905
906static void esp_input_done_esn(void *data, int err)
907{
908 struct sk_buff *skb = data;
909
910 esp_input_restore_header(skb);
911 esp_input_done(data, err);
912}
913
914static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
915{
916 struct crypto_aead *aead = x->data;
917 struct aead_request *req;
918 struct sk_buff *trailer;
919 int ivlen = crypto_aead_ivsize(aead);
920 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
921 int nfrags;
922 int assoclen;
923 int seqhilen;
924 int ret = 0;
925 void *tmp;
926 __be32 *seqhi;
927 u8 *iv;
928 struct scatterlist *sg;
929
930 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) {
931 ret = -EINVAL;
932 goto out;
933 }
934
935 if (elen <= 0) {
936 ret = -EINVAL;
937 goto out;
938 }
939
940 assoclen = sizeof(struct ip_esp_hdr);
941 seqhilen = 0;
942
943 if (x->props.flags & XFRM_STATE_ESN) {
944 seqhilen += sizeof(__be32);
945 assoclen += seqhilen;
946 }
947
948 if (!skb_cloned(skb)) {
949 if (!skb_is_nonlinear(skb)) {
950 nfrags = 1;
951
952 goto skip_cow;
953 } else if (!skb_has_frag_list(skb)) {
954 nfrags = skb_shinfo(skb)->nr_frags;
955 nfrags++;
956
957 goto skip_cow;
958 }
959 }
960
961 nfrags = skb_cow_data(skb, 0, &trailer);
962 if (nfrags < 0) {
963 ret = -EINVAL;
964 goto out;
965 }
966
967skip_cow:
968 ret = -ENOMEM;
969 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
970 if (!tmp)
971 goto out;
972
973 ESP_SKB_CB(skb)->tmp = tmp;
974 seqhi = esp_tmp_extra(tmp);
975 iv = esp_tmp_iv(aead, tmp, seqhilen);
976 req = esp_tmp_req(aead, iv);
977 sg = esp_req_sg(aead, req);
978
979 esp_input_set_header(skb, seqhi);
980
981 sg_init_table(sg, nfrags);
982 ret = skb_to_sgvec(skb, sg, 0, skb->len);
983 if (unlikely(ret < 0)) {
984 kfree(tmp);
985 goto out;
986 }
987
988 skb->ip_summed = CHECKSUM_NONE;
989
990 if ((x->props.flags & XFRM_STATE_ESN))
991 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
992 else
993 aead_request_set_callback(req, 0, esp_input_done, skb);
994
995 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
996 aead_request_set_ad(req, assoclen);
997
998 ret = crypto_aead_decrypt(req);
999 if (ret == -EINPROGRESS)
1000 goto out;
1001
1002 if ((x->props.flags & XFRM_STATE_ESN))
1003 esp_input_restore_header(skb);
1004
1005 ret = esp6_input_done2(skb, ret);
1006
1007out:
1008 return ret;
1009}
1010
1011static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
1012 u8 type, u8 code, int offset, __be32 info)
1013{
1014 struct net *net = dev_net(skb->dev);
1015 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
1016 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
1017 struct xfrm_state *x;
1018
1019 if (type != ICMPV6_PKT_TOOBIG &&
1020 type != NDISC_REDIRECT)
1021 return 0;
1022
1023 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
1024 esph->spi, IPPROTO_ESP, AF_INET6);
1025 if (!x)
1026 return 0;
1027
1028 if (type == NDISC_REDIRECT)
1029 ip6_redirect(skb, net, skb->dev->ifindex, 0,
1030 sock_net_uid(net, NULL));
1031 else
1032 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
1033 xfrm_state_put(x);
1034
1035 return 0;
1036}
1037
1038static void esp6_destroy(struct xfrm_state *x)
1039{
1040 struct crypto_aead *aead = x->data;
1041
1042 if (!aead)
1043 return;
1044
1045 crypto_free_aead(aead);
1046}
1047
1048static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
1049{
1050 char aead_name[CRYPTO_MAX_ALG_NAME];
1051 struct crypto_aead *aead;
1052 int err;
1053
1054 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1055 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
1056 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1057 return -ENAMETOOLONG;
1058 }
1059
1060 aead = crypto_alloc_aead(aead_name, 0, 0);
1061 err = PTR_ERR(aead);
1062 if (IS_ERR(aead))
1063 goto error;
1064
1065 x->data = aead;
1066
1067 err = crypto_aead_setkey(aead, x->aead->alg_key,
1068 (x->aead->alg_key_len + 7) / 8);
1069 if (err)
1070 goto error;
1071
1072 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1073 if (err)
1074 goto error;
1075
1076 return 0;
1077
1078error:
1079 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1080 return err;
1081}
1082
1083static int esp_init_authenc(struct xfrm_state *x,
1084 struct netlink_ext_ack *extack)
1085{
1086 struct crypto_aead *aead;
1087 struct crypto_authenc_key_param *param;
1088 struct rtattr *rta;
1089 char *key;
1090 char *p;
1091 char authenc_name[CRYPTO_MAX_ALG_NAME];
1092 unsigned int keylen;
1093 int err;
1094
1095 err = -ENAMETOOLONG;
1096
1097 if ((x->props.flags & XFRM_STATE_ESN)) {
1098 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1099 "%s%sauthencesn(%s,%s)%s",
1100 x->geniv ?: "", x->geniv ? "(" : "",
1101 x->aalg ? x->aalg->alg_name : "digest_null",
1102 x->ealg->alg_name,
1103 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1104 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1105 goto error;
1106 }
1107 } else {
1108 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1109 "%s%sauthenc(%s,%s)%s",
1110 x->geniv ?: "", x->geniv ? "(" : "",
1111 x->aalg ? x->aalg->alg_name : "digest_null",
1112 x->ealg->alg_name,
1113 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1114 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1115 goto error;
1116 }
1117 }
1118
1119 aead = crypto_alloc_aead(authenc_name, 0, 0);
1120 err = PTR_ERR(aead);
1121 if (IS_ERR(aead)) {
1122 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1123 goto error;
1124 }
1125
1126 x->data = aead;
1127
1128 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1129 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1130 err = -ENOMEM;
1131 key = kmalloc(keylen, GFP_KERNEL);
1132 if (!key)
1133 goto error;
1134
1135 p = key;
1136 rta = (void *)p;
1137 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1138 rta->rta_len = RTA_LENGTH(sizeof(*param));
1139 param = RTA_DATA(rta);
1140 p += RTA_SPACE(sizeof(*param));
1141
1142 if (x->aalg) {
1143 struct xfrm_algo_desc *aalg_desc;
1144
1145 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1146 p += (x->aalg->alg_key_len + 7) / 8;
1147
1148 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1149 BUG_ON(!aalg_desc);
1150
1151 err = -EINVAL;
1152 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1153 crypto_aead_authsize(aead)) {
1154 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1155 goto free_key;
1156 }
1157
1158 err = crypto_aead_setauthsize(
1159 aead, x->aalg->alg_trunc_len / 8);
1160 if (err) {
1161 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1162 goto free_key;
1163 }
1164 }
1165
1166 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1167 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1168
1169 err = crypto_aead_setkey(aead, key, keylen);
1170
1171free_key:
1172 kfree(key);
1173
1174error:
1175 return err;
1176}
1177
1178static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1179{
1180 struct crypto_aead *aead;
1181 u32 align;
1182 int err;
1183
1184 x->data = NULL;
1185
1186 if (x->aead) {
1187 err = esp_init_aead(x, extack);
1188 } else if (x->ealg) {
1189 err = esp_init_authenc(x, extack);
1190 } else {
1191 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1192 err = -EINVAL;
1193 }
1194
1195 if (err)
1196 goto error;
1197
1198 aead = x->data;
1199
1200 x->props.header_len = sizeof(struct ip_esp_hdr) +
1201 crypto_aead_ivsize(aead);
1202 switch (x->props.mode) {
1203 case XFRM_MODE_BEET:
1204 if (x->sel.family != AF_INET6)
1205 x->props.header_len += IPV4_BEET_PHMAXLEN +
1206 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
1207 break;
1208 default:
1209 case XFRM_MODE_TRANSPORT:
1210 break;
1211 case XFRM_MODE_TUNNEL:
1212 x->props.header_len += sizeof(struct ipv6hdr);
1213 break;
1214 }
1215
1216 if (x->encap) {
1217 struct xfrm_encap_tmpl *encap = x->encap;
1218
1219 switch (encap->encap_type) {
1220 default:
1221 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1222 err = -EINVAL;
1223 goto error;
1224 case UDP_ENCAP_ESPINUDP:
1225 x->props.header_len += sizeof(struct udphdr);
1226 break;
1227#ifdef CONFIG_INET6_ESPINTCP
1228 case TCP_ENCAP_ESPINTCP:
1229 /* only the length field, TCP encap is done by
1230 * the socket
1231 */
1232 x->props.header_len += 2;
1233 break;
1234#endif
1235 }
1236 }
1237
1238 align = ALIGN(crypto_aead_blocksize(aead), 4);
1239 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1240
1241error:
1242 return err;
1243}
1244
1245static int esp6_rcv_cb(struct sk_buff *skb, int err)
1246{
1247 return 0;
1248}
1249
1250static const struct xfrm_type esp6_type = {
1251 .owner = THIS_MODULE,
1252 .proto = IPPROTO_ESP,
1253 .flags = XFRM_TYPE_REPLAY_PROT,
1254 .init_state = esp6_init_state,
1255 .destructor = esp6_destroy,
1256 .input = esp6_input,
1257 .output = esp6_output,
1258};
1259
1260static struct xfrm6_protocol esp6_protocol = {
1261 .handler = xfrm6_rcv,
1262 .input_handler = xfrm_input,
1263 .cb_handler = esp6_rcv_cb,
1264 .err_handler = esp6_err,
1265 .priority = 0,
1266};
1267
1268static int __init esp6_init(void)
1269{
1270 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
1271 pr_info("%s: can't add xfrm type\n", __func__);
1272 return -EAGAIN;
1273 }
1274 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
1275 pr_info("%s: can't add protocol\n", __func__);
1276 xfrm_unregister_type(&esp6_type, AF_INET6);
1277 return -EAGAIN;
1278 }
1279
1280 return 0;
1281}
1282
1283static void __exit esp6_fini(void)
1284{
1285 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
1286 pr_info("%s: can't remove protocol\n", __func__);
1287 xfrm_unregister_type(&esp6_type, AF_INET6);
1288}
1289
1290module_init(esp6_init);
1291module_exit(esp6_fini);
1292
1293MODULE_DESCRIPTION("IPv6 ESP transformation helpers");
1294MODULE_LICENSE("GPL");
1295MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);