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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
40#include <linux/highmem.h>
41
42struct esp_skb_cb {
43 struct xfrm_skb_cb xfrm;
44 void *tmp;
45};
46
47struct esp_output_extra {
48 __be32 seqhi;
49 u32 esphoff;
50};
51
52#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
53
54/*
55 * Allocate an AEAD request structure with extra space for SG and IV.
56 *
57 * For alignment considerations the upper 32 bits of the sequence number are
58 * placed at the front, if present. Followed by the IV, the request and finally
59 * the SG list.
60 *
61 * TODO: Use spare space in skb for this where possible.
62 */
63static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
64{
65 unsigned int len;
66
67 len = seqihlen;
68
69 len += crypto_aead_ivsize(aead);
70
71 if (len) {
72 len += crypto_aead_alignmask(aead) &
73 ~(crypto_tfm_ctx_alignment() - 1);
74 len = ALIGN(len, crypto_tfm_ctx_alignment());
75 }
76
77 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
78 len = ALIGN(len, __alignof__(struct scatterlist));
79
80 len += sizeof(struct scatterlist) * nfrags;
81
82 return kmalloc(len, GFP_ATOMIC);
83}
84
85static inline void *esp_tmp_extra(void *tmp)
86{
87 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
88}
89
90static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
91{
92 return crypto_aead_ivsize(aead) ?
93 PTR_ALIGN((u8 *)tmp + seqhilen,
94 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
95}
96
97static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
98{
99 struct aead_request *req;
100
101 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
102 crypto_tfm_ctx_alignment());
103 aead_request_set_tfm(req, aead);
104 return req;
105}
106
107static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
108 struct aead_request *req)
109{
110 return (void *)ALIGN((unsigned long)(req + 1) +
111 crypto_aead_reqsize(aead),
112 __alignof__(struct scatterlist));
113}
114
115static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
116{
117 struct crypto_aead *aead = x->data;
118 int extralen = 0;
119 u8 *iv;
120 struct aead_request *req;
121 struct scatterlist *sg;
122
123 if (x->props.flags & XFRM_STATE_ESN)
124 extralen += sizeof(struct esp_output_extra);
125
126 iv = esp_tmp_iv(aead, tmp, extralen);
127 req = esp_tmp_req(aead, iv);
128
129 /* Unref skb_frag_pages in the src scatterlist if necessary.
130 * Skip the first sg which comes from skb->data.
131 */
132 if (req->src != req->dst)
133 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
134 put_page(sg_page(sg));
135}
136
137#ifdef CONFIG_INET6_ESPINTCP
138struct esp_tcp_sk {
139 struct sock *sk;
140 struct rcu_head rcu;
141};
142
143static void esp_free_tcp_sk(struct rcu_head *head)
144{
145 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
146
147 sock_put(esk->sk);
148 kfree(esk);
149}
150
151static struct sock *esp6_find_tcp_sk(struct xfrm_state *x)
152{
153 struct xfrm_encap_tmpl *encap = x->encap;
154 struct net *net = xs_net(x);
155 struct esp_tcp_sk *esk;
156 __be16 sport, dport;
157 struct sock *nsk;
158 struct sock *sk;
159
160 sk = rcu_dereference(x->encap_sk);
161 if (sk && sk->sk_state == TCP_ESTABLISHED)
162 return sk;
163
164 spin_lock_bh(&x->lock);
165 sport = encap->encap_sport;
166 dport = encap->encap_dport;
167 nsk = rcu_dereference_protected(x->encap_sk,
168 lockdep_is_held(&x->lock));
169 if (sk && sk == nsk) {
170 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
171 if (!esk) {
172 spin_unlock_bh(&x->lock);
173 return ERR_PTR(-ENOMEM);
174 }
175 RCU_INIT_POINTER(x->encap_sk, NULL);
176 esk->sk = sk;
177 call_rcu(&esk->rcu, esp_free_tcp_sk);
178 }
179 spin_unlock_bh(&x->lock);
180
181 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, &x->id.daddr.in6,
182 dport, &x->props.saddr.in6, ntohs(sport), 0, 0);
183 if (!sk)
184 return ERR_PTR(-ENOENT);
185
186 if (!tcp_is_ulp_esp(sk)) {
187 sock_put(sk);
188 return ERR_PTR(-EINVAL);
189 }
190
191 spin_lock_bh(&x->lock);
192 nsk = rcu_dereference_protected(x->encap_sk,
193 lockdep_is_held(&x->lock));
194 if (encap->encap_sport != sport ||
195 encap->encap_dport != dport) {
196 sock_put(sk);
197 sk = nsk ?: ERR_PTR(-EREMCHG);
198 } else if (sk == nsk) {
199 sock_put(sk);
200 } else {
201 rcu_assign_pointer(x->encap_sk, sk);
202 }
203 spin_unlock_bh(&x->lock);
204
205 return sk;
206}
207
208static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
209{
210 struct sock *sk;
211 int err;
212
213 rcu_read_lock();
214
215 sk = esp6_find_tcp_sk(x);
216 err = PTR_ERR_OR_ZERO(sk);
217 if (err)
218 goto out;
219
220 bh_lock_sock(sk);
221 if (sock_owned_by_user(sk))
222 err = espintcp_queue_out(sk, skb);
223 else
224 err = espintcp_push_skb(sk, skb);
225 bh_unlock_sock(sk);
226
227out:
228 rcu_read_unlock();
229 return err;
230}
231
232static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
233 struct sk_buff *skb)
234{
235 struct dst_entry *dst = skb_dst(skb);
236 struct xfrm_state *x = dst->xfrm;
237
238 return esp_output_tcp_finish(x, skb);
239}
240
241static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
242{
243 int err;
244
245 local_bh_disable();
246 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
247 local_bh_enable();
248
249 /* EINPROGRESS just happens to do the right thing. It
250 * actually means that the skb has been consumed and
251 * isn't coming back.
252 */
253 return err ?: -EINPROGRESS;
254}
255#else
256static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
257{
258 kfree_skb(skb);
259
260 return -EOPNOTSUPP;
261}
262#endif
263
264static void esp_output_encap_csum(struct sk_buff *skb)
265{
266 /* UDP encap with IPv6 requires a valid checksum */
267 if (*skb_mac_header(skb) == IPPROTO_UDP) {
268 struct udphdr *uh = udp_hdr(skb);
269 struct ipv6hdr *ip6h = ipv6_hdr(skb);
270 int len = ntohs(uh->len);
271 unsigned int offset = skb_transport_offset(skb);
272 __wsum csum = skb_checksum(skb, offset, skb->len - offset, 0);
273
274 uh->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
275 len, IPPROTO_UDP, csum);
276 if (uh->check == 0)
277 uh->check = CSUM_MANGLED_0;
278 }
279}
280
281static void esp_output_done(void *data, int err)
282{
283 struct sk_buff *skb = data;
284 struct xfrm_offload *xo = xfrm_offload(skb);
285 void *tmp;
286 struct xfrm_state *x;
287
288 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
289 struct sec_path *sp = skb_sec_path(skb);
290
291 x = sp->xvec[sp->len - 1];
292 } else {
293 x = skb_dst(skb)->xfrm;
294 }
295
296 tmp = ESP_SKB_CB(skb)->tmp;
297 esp_ssg_unref(x, tmp);
298 kfree(tmp);
299
300 esp_output_encap_csum(skb);
301
302 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
303 if (err) {
304 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
305 kfree_skb(skb);
306 return;
307 }
308
309 skb_push(skb, skb->data - skb_mac_header(skb));
310 secpath_reset(skb);
311 xfrm_dev_resume(skb);
312 } else {
313 if (!err &&
314 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
315 esp_output_tail_tcp(x, skb);
316 else
317 xfrm_output_resume(skb->sk, skb, err);
318 }
319}
320
321/* Move ESP header back into place. */
322static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
323{
324 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
325 void *tmp = ESP_SKB_CB(skb)->tmp;
326 __be32 *seqhi = esp_tmp_extra(tmp);
327
328 esph->seq_no = esph->spi;
329 esph->spi = *seqhi;
330}
331
332static void esp_output_restore_header(struct sk_buff *skb)
333{
334 void *tmp = ESP_SKB_CB(skb)->tmp;
335 struct esp_output_extra *extra = esp_tmp_extra(tmp);
336
337 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
338 sizeof(__be32));
339}
340
341static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
342 struct xfrm_state *x,
343 struct ip_esp_hdr *esph,
344 struct esp_output_extra *extra)
345{
346 /* For ESN we move the header forward by 4 bytes to
347 * accommodate the high bits. We will move it back after
348 * encryption.
349 */
350 if ((x->props.flags & XFRM_STATE_ESN)) {
351 __u32 seqhi;
352 struct xfrm_offload *xo = xfrm_offload(skb);
353
354 if (xo)
355 seqhi = xo->seq.hi;
356 else
357 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
358
359 extra->esphoff = (unsigned char *)esph -
360 skb_transport_header(skb);
361 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
362 extra->seqhi = esph->spi;
363 esph->seq_no = htonl(seqhi);
364 }
365
366 esph->spi = x->id.spi;
367
368 return esph;
369}
370
371static void esp_output_done_esn(void *data, int err)
372{
373 struct sk_buff *skb = data;
374
375 esp_output_restore_header(skb);
376 esp_output_done(data, err);
377}
378
379static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb,
380 int encap_type,
381 struct esp_info *esp,
382 __be16 sport,
383 __be16 dport)
384{
385 struct udphdr *uh;
386 __be32 *udpdata32;
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 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
402 udpdata32 = (__be32 *)(uh + 1);
403 udpdata32[0] = udpdata32[1] = 0;
404 return (struct ip_esp_hdr *)(udpdata32 + 2);
405 }
406
407 return (struct ip_esp_hdr *)(uh + 1);
408}
409
410#ifdef CONFIG_INET6_ESPINTCP
411static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
412 struct sk_buff *skb,
413 struct esp_info *esp)
414{
415 __be16 *lenp = (void *)esp->esph;
416 struct ip_esp_hdr *esph;
417 unsigned int len;
418 struct sock *sk;
419
420 len = skb->len + esp->tailen - skb_transport_offset(skb);
421 if (len > IP_MAX_MTU)
422 return ERR_PTR(-EMSGSIZE);
423
424 rcu_read_lock();
425 sk = esp6_find_tcp_sk(x);
426 rcu_read_unlock();
427
428 if (IS_ERR(sk))
429 return ERR_CAST(sk);
430
431 *lenp = htons(len);
432 esph = (struct ip_esp_hdr *)(lenp + 1);
433
434 return esph;
435}
436#else
437static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
438 struct sk_buff *skb,
439 struct esp_info *esp)
440{
441 return ERR_PTR(-EOPNOTSUPP);
442}
443#endif
444
445static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb,
446 struct esp_info *esp)
447{
448 struct xfrm_encap_tmpl *encap = x->encap;
449 struct ip_esp_hdr *esph;
450 __be16 sport, dport;
451 int encap_type;
452
453 spin_lock_bh(&x->lock);
454 sport = encap->encap_sport;
455 dport = encap->encap_dport;
456 encap_type = encap->encap_type;
457 spin_unlock_bh(&x->lock);
458
459 switch (encap_type) {
460 default:
461 case UDP_ENCAP_ESPINUDP:
462 case UDP_ENCAP_ESPINUDP_NON_IKE:
463 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport);
464 break;
465 case TCP_ENCAP_ESPINTCP:
466 esph = esp6_output_tcp_encap(x, skb, esp);
467 break;
468 }
469
470 if (IS_ERR(esph))
471 return PTR_ERR(esph);
472
473 esp->esph = esph;
474
475 return 0;
476}
477
478int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
479{
480 u8 *tail;
481 int nfrags;
482 int esph_offset;
483 struct page *page;
484 struct sk_buff *trailer;
485 int tailen = esp->tailen;
486
487 if (x->encap) {
488 int err = esp6_output_encap(x, skb, esp);
489
490 if (err < 0)
491 return err;
492 }
493
494 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
495 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
496 goto cow;
497
498 if (!skb_cloned(skb)) {
499 if (tailen <= skb_tailroom(skb)) {
500 nfrags = 1;
501 trailer = skb;
502 tail = skb_tail_pointer(trailer);
503
504 goto skip_cow;
505 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
506 && !skb_has_frag_list(skb)) {
507 int allocsize;
508 struct sock *sk = skb->sk;
509 struct page_frag *pfrag = &x->xfrag;
510
511 esp->inplace = false;
512
513 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
514
515 spin_lock_bh(&x->lock);
516
517 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
518 spin_unlock_bh(&x->lock);
519 goto cow;
520 }
521
522 page = pfrag->page;
523 get_page(page);
524
525 tail = page_address(page) + pfrag->offset;
526
527 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
528
529 nfrags = skb_shinfo(skb)->nr_frags;
530
531 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
532 tailen);
533 skb_shinfo(skb)->nr_frags = ++nfrags;
534
535 pfrag->offset = pfrag->offset + allocsize;
536
537 spin_unlock_bh(&x->lock);
538
539 nfrags++;
540
541 skb->len += tailen;
542 skb->data_len += tailen;
543 skb->truesize += tailen;
544 if (sk && sk_fullsock(sk))
545 refcount_add(tailen, &sk->sk_wmem_alloc);
546
547 goto out;
548 }
549 }
550
551cow:
552 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
553
554 nfrags = skb_cow_data(skb, tailen, &trailer);
555 if (nfrags < 0)
556 goto out;
557 tail = skb_tail_pointer(trailer);
558 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
559
560skip_cow:
561 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
562 pskb_put(skb, trailer, tailen);
563
564out:
565 return nfrags;
566}
567EXPORT_SYMBOL_GPL(esp6_output_head);
568
569int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
570{
571 u8 *iv;
572 int alen;
573 void *tmp;
574 int ivlen;
575 int assoclen;
576 int extralen;
577 struct page *page;
578 struct ip_esp_hdr *esph;
579 struct aead_request *req;
580 struct crypto_aead *aead;
581 struct scatterlist *sg, *dsg;
582 struct esp_output_extra *extra;
583 int err = -ENOMEM;
584
585 assoclen = sizeof(struct ip_esp_hdr);
586 extralen = 0;
587
588 if (x->props.flags & XFRM_STATE_ESN) {
589 extralen += sizeof(*extra);
590 assoclen += sizeof(__be32);
591 }
592
593 aead = x->data;
594 alen = crypto_aead_authsize(aead);
595 ivlen = crypto_aead_ivsize(aead);
596
597 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
598 if (!tmp)
599 goto error;
600
601 extra = esp_tmp_extra(tmp);
602 iv = esp_tmp_iv(aead, tmp, extralen);
603 req = esp_tmp_req(aead, iv);
604 sg = esp_req_sg(aead, req);
605
606 if (esp->inplace)
607 dsg = sg;
608 else
609 dsg = &sg[esp->nfrags];
610
611 esph = esp_output_set_esn(skb, x, esp->esph, extra);
612 esp->esph = esph;
613
614 sg_init_table(sg, esp->nfrags);
615 err = skb_to_sgvec(skb, sg,
616 (unsigned char *)esph - skb->data,
617 assoclen + ivlen + esp->clen + alen);
618 if (unlikely(err < 0))
619 goto error_free;
620
621 if (!esp->inplace) {
622 int allocsize;
623 struct page_frag *pfrag = &x->xfrag;
624
625 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
626
627 spin_lock_bh(&x->lock);
628 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
629 spin_unlock_bh(&x->lock);
630 goto error_free;
631 }
632
633 skb_shinfo(skb)->nr_frags = 1;
634
635 page = pfrag->page;
636 get_page(page);
637 /* replace page frags in skb with new page */
638 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
639 pfrag->offset = pfrag->offset + allocsize;
640 spin_unlock_bh(&x->lock);
641
642 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
643 err = skb_to_sgvec(skb, dsg,
644 (unsigned char *)esph - skb->data,
645 assoclen + ivlen + esp->clen + alen);
646 if (unlikely(err < 0))
647 goto error_free;
648 }
649
650 if ((x->props.flags & XFRM_STATE_ESN))
651 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
652 else
653 aead_request_set_callback(req, 0, esp_output_done, skb);
654
655 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
656 aead_request_set_ad(req, assoclen);
657
658 memset(iv, 0, ivlen);
659 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
660 min(ivlen, 8));
661
662 ESP_SKB_CB(skb)->tmp = tmp;
663 err = crypto_aead_encrypt(req);
664
665 switch (err) {
666 case -EINPROGRESS:
667 goto error;
668
669 case -ENOSPC:
670 err = NET_XMIT_DROP;
671 break;
672
673 case 0:
674 if ((x->props.flags & XFRM_STATE_ESN))
675 esp_output_restore_header(skb);
676 esp_output_encap_csum(skb);
677 }
678
679 if (sg != dsg)
680 esp_ssg_unref(x, tmp);
681
682 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
683 err = esp_output_tail_tcp(x, skb);
684
685error_free:
686 kfree(tmp);
687error:
688 return err;
689}
690EXPORT_SYMBOL_GPL(esp6_output_tail);
691
692static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
693{
694 int alen;
695 int blksize;
696 struct ip_esp_hdr *esph;
697 struct crypto_aead *aead;
698 struct esp_info esp;
699
700 esp.inplace = true;
701
702 esp.proto = *skb_mac_header(skb);
703 *skb_mac_header(skb) = IPPROTO_ESP;
704
705 /* skb is pure payload to encrypt */
706
707 aead = x->data;
708 alen = crypto_aead_authsize(aead);
709
710 esp.tfclen = 0;
711 if (x->tfcpad) {
712 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
713 u32 padto;
714
715 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
716 if (skb->len < padto)
717 esp.tfclen = padto - skb->len;
718 }
719 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
720 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
721 esp.plen = esp.clen - skb->len - esp.tfclen;
722 esp.tailen = esp.tfclen + esp.plen + alen;
723
724 esp.esph = ip_esp_hdr(skb);
725
726 esp.nfrags = esp6_output_head(x, skb, &esp);
727 if (esp.nfrags < 0)
728 return esp.nfrags;
729
730 esph = esp.esph;
731 esph->spi = x->id.spi;
732
733 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
734 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
735 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
736
737 skb_push(skb, -skb_network_offset(skb));
738
739 return esp6_output_tail(x, skb, &esp);
740}
741
742static inline int esp_remove_trailer(struct sk_buff *skb)
743{
744 struct xfrm_state *x = xfrm_input_state(skb);
745 struct crypto_aead *aead = x->data;
746 int alen, hlen, elen;
747 int padlen, trimlen;
748 __wsum csumdiff;
749 u8 nexthdr[2];
750 int ret;
751
752 alen = crypto_aead_authsize(aead);
753 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
754 elen = skb->len - hlen;
755
756 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2);
757 BUG_ON(ret);
758
759 ret = -EINVAL;
760 padlen = nexthdr[0];
761 if (padlen + 2 + alen >= elen) {
762 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
763 padlen + 2, elen - alen);
764 goto out;
765 }
766
767 trimlen = alen + padlen + 2;
768 if (skb->ip_summed == CHECKSUM_COMPLETE) {
769 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
770 skb->csum = csum_block_sub(skb->csum, csumdiff,
771 skb->len - trimlen);
772 }
773 ret = pskb_trim(skb, skb->len - trimlen);
774 if (unlikely(ret))
775 return ret;
776
777 ret = nexthdr[1];
778
779out:
780 return ret;
781}
782
783int esp6_input_done2(struct sk_buff *skb, int err)
784{
785 struct xfrm_state *x = xfrm_input_state(skb);
786 struct xfrm_offload *xo = xfrm_offload(skb);
787 struct crypto_aead *aead = x->data;
788 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
789 int hdr_len = skb_network_header_len(skb);
790
791 if (!xo || !(xo->flags & CRYPTO_DONE))
792 kfree(ESP_SKB_CB(skb)->tmp);
793
794 if (unlikely(err))
795 goto out;
796
797 err = esp_remove_trailer(skb);
798 if (unlikely(err < 0))
799 goto out;
800
801 if (x->encap) {
802 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
803 int offset = skb_network_offset(skb) + sizeof(*ip6h);
804 struct xfrm_encap_tmpl *encap = x->encap;
805 u8 nexthdr = ip6h->nexthdr;
806 __be16 frag_off, source;
807 struct udphdr *uh;
808 struct tcphdr *th;
809
810 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
811 if (offset == -1) {
812 err = -EINVAL;
813 goto out;
814 }
815
816 uh = (void *)(skb->data + offset);
817 th = (void *)(skb->data + offset);
818 hdr_len += offset;
819
820 switch (x->encap->encap_type) {
821 case TCP_ENCAP_ESPINTCP:
822 source = th->source;
823 break;
824 case UDP_ENCAP_ESPINUDP:
825 case UDP_ENCAP_ESPINUDP_NON_IKE:
826 source = uh->source;
827 break;
828 default:
829 WARN_ON_ONCE(1);
830 err = -EINVAL;
831 goto out;
832 }
833
834 /*
835 * 1) if the NAT-T peer's IP or port changed then
836 * advertise the change to the keying daemon.
837 * This is an inbound SA, so just compare
838 * SRC ports.
839 */
840 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) ||
841 source != encap->encap_sport) {
842 xfrm_address_t ipaddr;
843
844 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6));
845 km_new_mapping(x, &ipaddr, source);
846
847 /* XXX: perhaps add an extra
848 * policy check here, to see
849 * if we should allow or
850 * reject a packet from a
851 * different source
852 * address/port.
853 */
854 }
855
856 /*
857 * 2) ignore UDP/TCP checksums in case
858 * of NAT-T in Transport Mode, or
859 * perform other post-processing fixes
860 * as per draft-ietf-ipsec-udp-encaps-06,
861 * section 3.1.2
862 */
863 if (x->props.mode == XFRM_MODE_TRANSPORT)
864 skb->ip_summed = CHECKSUM_UNNECESSARY;
865 }
866
867 skb_postpull_rcsum(skb, skb_network_header(skb),
868 skb_network_header_len(skb));
869 skb_pull_rcsum(skb, hlen);
870 if (x->props.mode == XFRM_MODE_TUNNEL)
871 skb_reset_transport_header(skb);
872 else
873 skb_set_transport_header(skb, -hdr_len);
874
875 /* RFC4303: Drop dummy packets without any error */
876 if (err == IPPROTO_NONE)
877 err = -EINVAL;
878
879out:
880 return err;
881}
882EXPORT_SYMBOL_GPL(esp6_input_done2);
883
884static void esp_input_done(void *data, int err)
885{
886 struct sk_buff *skb = data;
887
888 xfrm_input_resume(skb, esp6_input_done2(skb, err));
889}
890
891static void esp_input_restore_header(struct sk_buff *skb)
892{
893 esp_restore_header(skb, 0);
894 __skb_pull(skb, 4);
895}
896
897static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
898{
899 struct xfrm_state *x = xfrm_input_state(skb);
900
901 /* For ESN we move the header forward by 4 bytes to
902 * accommodate the high bits. We will move it back after
903 * decryption.
904 */
905 if ((x->props.flags & XFRM_STATE_ESN)) {
906 struct ip_esp_hdr *esph = skb_push(skb, 4);
907
908 *seqhi = esph->spi;
909 esph->spi = esph->seq_no;
910 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
911 }
912}
913
914static void esp_input_done_esn(void *data, int err)
915{
916 struct sk_buff *skb = data;
917
918 esp_input_restore_header(skb);
919 esp_input_done(data, err);
920}
921
922static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
923{
924 struct crypto_aead *aead = x->data;
925 struct aead_request *req;
926 struct sk_buff *trailer;
927 int ivlen = crypto_aead_ivsize(aead);
928 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
929 int nfrags;
930 int assoclen;
931 int seqhilen;
932 int ret = 0;
933 void *tmp;
934 __be32 *seqhi;
935 u8 *iv;
936 struct scatterlist *sg;
937
938 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) {
939 ret = -EINVAL;
940 goto out;
941 }
942
943 if (elen <= 0) {
944 ret = -EINVAL;
945 goto out;
946 }
947
948 assoclen = sizeof(struct ip_esp_hdr);
949 seqhilen = 0;
950
951 if (x->props.flags & XFRM_STATE_ESN) {
952 seqhilen += sizeof(__be32);
953 assoclen += seqhilen;
954 }
955
956 if (!skb_cloned(skb)) {
957 if (!skb_is_nonlinear(skb)) {
958 nfrags = 1;
959
960 goto skip_cow;
961 } else if (!skb_has_frag_list(skb)) {
962 nfrags = skb_shinfo(skb)->nr_frags;
963 nfrags++;
964
965 goto skip_cow;
966 }
967 }
968
969 nfrags = skb_cow_data(skb, 0, &trailer);
970 if (nfrags < 0) {
971 ret = -EINVAL;
972 goto out;
973 }
974
975skip_cow:
976 ret = -ENOMEM;
977 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
978 if (!tmp)
979 goto out;
980
981 ESP_SKB_CB(skb)->tmp = tmp;
982 seqhi = esp_tmp_extra(tmp);
983 iv = esp_tmp_iv(aead, tmp, seqhilen);
984 req = esp_tmp_req(aead, iv);
985 sg = esp_req_sg(aead, req);
986
987 esp_input_set_header(skb, seqhi);
988
989 sg_init_table(sg, nfrags);
990 ret = skb_to_sgvec(skb, sg, 0, skb->len);
991 if (unlikely(ret < 0)) {
992 kfree(tmp);
993 goto out;
994 }
995
996 skb->ip_summed = CHECKSUM_NONE;
997
998 if ((x->props.flags & XFRM_STATE_ESN))
999 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
1000 else
1001 aead_request_set_callback(req, 0, esp_input_done, skb);
1002
1003 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
1004 aead_request_set_ad(req, assoclen);
1005
1006 ret = crypto_aead_decrypt(req);
1007 if (ret == -EINPROGRESS)
1008 goto out;
1009
1010 if ((x->props.flags & XFRM_STATE_ESN))
1011 esp_input_restore_header(skb);
1012
1013 ret = esp6_input_done2(skb, ret);
1014
1015out:
1016 return ret;
1017}
1018
1019static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
1020 u8 type, u8 code, int offset, __be32 info)
1021{
1022 struct net *net = dev_net(skb->dev);
1023 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
1024 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
1025 struct xfrm_state *x;
1026
1027 if (type != ICMPV6_PKT_TOOBIG &&
1028 type != NDISC_REDIRECT)
1029 return 0;
1030
1031 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
1032 esph->spi, IPPROTO_ESP, AF_INET6);
1033 if (!x)
1034 return 0;
1035
1036 if (type == NDISC_REDIRECT)
1037 ip6_redirect(skb, net, skb->dev->ifindex, 0,
1038 sock_net_uid(net, NULL));
1039 else
1040 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
1041 xfrm_state_put(x);
1042
1043 return 0;
1044}
1045
1046static void esp6_destroy(struct xfrm_state *x)
1047{
1048 struct crypto_aead *aead = x->data;
1049
1050 if (!aead)
1051 return;
1052
1053 crypto_free_aead(aead);
1054}
1055
1056static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
1057{
1058 char aead_name[CRYPTO_MAX_ALG_NAME];
1059 struct crypto_aead *aead;
1060 int err;
1061
1062 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1063 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
1064 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1065 return -ENAMETOOLONG;
1066 }
1067
1068 aead = crypto_alloc_aead(aead_name, 0, 0);
1069 err = PTR_ERR(aead);
1070 if (IS_ERR(aead))
1071 goto error;
1072
1073 x->data = aead;
1074
1075 err = crypto_aead_setkey(aead, x->aead->alg_key,
1076 (x->aead->alg_key_len + 7) / 8);
1077 if (err)
1078 goto error;
1079
1080 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1081 if (err)
1082 goto error;
1083
1084 return 0;
1085
1086error:
1087 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1088 return err;
1089}
1090
1091static int esp_init_authenc(struct xfrm_state *x,
1092 struct netlink_ext_ack *extack)
1093{
1094 struct crypto_aead *aead;
1095 struct crypto_authenc_key_param *param;
1096 struct rtattr *rta;
1097 char *key;
1098 char *p;
1099 char authenc_name[CRYPTO_MAX_ALG_NAME];
1100 unsigned int keylen;
1101 int err;
1102
1103 err = -ENAMETOOLONG;
1104
1105 if ((x->props.flags & XFRM_STATE_ESN)) {
1106 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1107 "%s%sauthencesn(%s,%s)%s",
1108 x->geniv ?: "", x->geniv ? "(" : "",
1109 x->aalg ? x->aalg->alg_name : "digest_null",
1110 x->ealg->alg_name,
1111 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1112 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1113 goto error;
1114 }
1115 } else {
1116 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1117 "%s%sauthenc(%s,%s)%s",
1118 x->geniv ?: "", x->geniv ? "(" : "",
1119 x->aalg ? x->aalg->alg_name : "digest_null",
1120 x->ealg->alg_name,
1121 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1122 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1123 goto error;
1124 }
1125 }
1126
1127 aead = crypto_alloc_aead(authenc_name, 0, 0);
1128 err = PTR_ERR(aead);
1129 if (IS_ERR(aead)) {
1130 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1131 goto error;
1132 }
1133
1134 x->data = aead;
1135
1136 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1137 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1138 err = -ENOMEM;
1139 key = kmalloc(keylen, GFP_KERNEL);
1140 if (!key)
1141 goto error;
1142
1143 p = key;
1144 rta = (void *)p;
1145 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1146 rta->rta_len = RTA_LENGTH(sizeof(*param));
1147 param = RTA_DATA(rta);
1148 p += RTA_SPACE(sizeof(*param));
1149
1150 if (x->aalg) {
1151 struct xfrm_algo_desc *aalg_desc;
1152
1153 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1154 p += (x->aalg->alg_key_len + 7) / 8;
1155
1156 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1157 BUG_ON(!aalg_desc);
1158
1159 err = -EINVAL;
1160 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1161 crypto_aead_authsize(aead)) {
1162 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1163 goto free_key;
1164 }
1165
1166 err = crypto_aead_setauthsize(
1167 aead, x->aalg->alg_trunc_len / 8);
1168 if (err) {
1169 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1170 goto free_key;
1171 }
1172 }
1173
1174 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1175 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1176
1177 err = crypto_aead_setkey(aead, key, keylen);
1178
1179free_key:
1180 kfree(key);
1181
1182error:
1183 return err;
1184}
1185
1186static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1187{
1188 struct crypto_aead *aead;
1189 u32 align;
1190 int err;
1191
1192 x->data = NULL;
1193
1194 if (x->aead) {
1195 err = esp_init_aead(x, extack);
1196 } else if (x->ealg) {
1197 err = esp_init_authenc(x, extack);
1198 } else {
1199 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1200 err = -EINVAL;
1201 }
1202
1203 if (err)
1204 goto error;
1205
1206 aead = x->data;
1207
1208 x->props.header_len = sizeof(struct ip_esp_hdr) +
1209 crypto_aead_ivsize(aead);
1210 switch (x->props.mode) {
1211 case XFRM_MODE_BEET:
1212 if (x->sel.family != AF_INET6)
1213 x->props.header_len += IPV4_BEET_PHMAXLEN +
1214 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
1215 break;
1216 default:
1217 case XFRM_MODE_TRANSPORT:
1218 break;
1219 case XFRM_MODE_TUNNEL:
1220 x->props.header_len += sizeof(struct ipv6hdr);
1221 break;
1222 }
1223
1224 if (x->encap) {
1225 struct xfrm_encap_tmpl *encap = x->encap;
1226
1227 switch (encap->encap_type) {
1228 default:
1229 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1230 err = -EINVAL;
1231 goto error;
1232 case UDP_ENCAP_ESPINUDP:
1233 x->props.header_len += sizeof(struct udphdr);
1234 break;
1235 case UDP_ENCAP_ESPINUDP_NON_IKE:
1236 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1237 break;
1238#ifdef CONFIG_INET6_ESPINTCP
1239 case TCP_ENCAP_ESPINTCP:
1240 /* only the length field, TCP encap is done by
1241 * the socket
1242 */
1243 x->props.header_len += 2;
1244 break;
1245#endif
1246 }
1247 }
1248
1249 align = ALIGN(crypto_aead_blocksize(aead), 4);
1250 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1251
1252error:
1253 return err;
1254}
1255
1256static int esp6_rcv_cb(struct sk_buff *skb, int err)
1257{
1258 return 0;
1259}
1260
1261static const struct xfrm_type esp6_type = {
1262 .owner = THIS_MODULE,
1263 .proto = IPPROTO_ESP,
1264 .flags = XFRM_TYPE_REPLAY_PROT,
1265 .init_state = esp6_init_state,
1266 .destructor = esp6_destroy,
1267 .input = esp6_input,
1268 .output = esp6_output,
1269};
1270
1271static struct xfrm6_protocol esp6_protocol = {
1272 .handler = xfrm6_rcv,
1273 .input_handler = xfrm_input,
1274 .cb_handler = esp6_rcv_cb,
1275 .err_handler = esp6_err,
1276 .priority = 0,
1277};
1278
1279static int __init esp6_init(void)
1280{
1281 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
1282 pr_info("%s: can't add xfrm type\n", __func__);
1283 return -EAGAIN;
1284 }
1285 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
1286 pr_info("%s: can't add protocol\n", __func__);
1287 xfrm_unregister_type(&esp6_type, AF_INET6);
1288 return -EAGAIN;
1289 }
1290
1291 return 0;
1292}
1293
1294static void __exit esp6_fini(void)
1295{
1296 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
1297 pr_info("%s: can't remove protocol\n", __func__);
1298 xfrm_unregister_type(&esp6_type, AF_INET6);
1299}
1300
1301module_init(esp6_init);
1302module_exit(esp6_fini);
1303
1304MODULE_DESCRIPTION("IPv6 ESP transformation helpers");
1305MODULE_LICENSE("GPL");
1306MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);