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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, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 *
18 * Authors
19 *
20 * Mitsuru KANDA @USAGI : IPv6 Support
21 * Kazunori MIYAZAWA @USAGI :
22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
23 *
24 * This file is derived from net/ipv4/esp.c
25 */
26
27#include <crypto/aead.h>
28#include <crypto/authenc.h>
29#include <linux/err.h>
30#include <linux/module.h>
31#include <net/ip.h>
32#include <net/xfrm.h>
33#include <net/esp.h>
34#include <linux/scatterlist.h>
35#include <linux/kernel.h>
36#include <linux/pfkeyv2.h>
37#include <linux/random.h>
38#include <linux/slab.h>
39#include <linux/spinlock.h>
40#include <net/icmp.h>
41#include <net/ipv6.h>
42#include <net/protocol.h>
43#include <linux/icmpv6.h>
44
45struct esp_skb_cb {
46 struct xfrm_skb_cb xfrm;
47 void *tmp;
48};
49
50#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
51
52static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
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_givcrypt_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 __be32 *esp_tmp_seqhi(void *tmp)
86{
87 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
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_givcrypt_request *esp_tmp_givreq(
98 struct crypto_aead *aead, u8 *iv)
99{
100 struct aead_givcrypt_request *req;
101
102 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
103 crypto_tfm_ctx_alignment());
104 aead_givcrypt_set_tfm(req, aead);
105 return req;
106}
107
108static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
109{
110 struct aead_request *req;
111
112 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
113 crypto_tfm_ctx_alignment());
114 aead_request_set_tfm(req, aead);
115 return req;
116}
117
118static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
119 struct aead_request *req)
120{
121 return (void *)ALIGN((unsigned long)(req + 1) +
122 crypto_aead_reqsize(aead),
123 __alignof__(struct scatterlist));
124}
125
126static inline struct scatterlist *esp_givreq_sg(
127 struct crypto_aead *aead, struct aead_givcrypt_request *req)
128{
129 return (void *)ALIGN((unsigned long)(req + 1) +
130 crypto_aead_reqsize(aead),
131 __alignof__(struct scatterlist));
132}
133
134static void esp_output_done(struct crypto_async_request *base, int err)
135{
136 struct sk_buff *skb = base->data;
137
138 kfree(ESP_SKB_CB(skb)->tmp);
139 xfrm_output_resume(skb, err);
140}
141
142static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
143{
144 int err;
145 struct ip_esp_hdr *esph;
146 struct crypto_aead *aead;
147 struct aead_givcrypt_request *req;
148 struct scatterlist *sg;
149 struct scatterlist *asg;
150 struct sk_buff *trailer;
151 void *tmp;
152 int blksize;
153 int clen;
154 int alen;
155 int plen;
156 int tfclen;
157 int nfrags;
158 int assoclen;
159 int sglists;
160 int seqhilen;
161 u8 *iv;
162 u8 *tail;
163 __be32 *seqhi;
164 struct esp_data *esp = x->data;
165
166 /* skb is pure payload to encrypt */
167 err = -ENOMEM;
168
169 aead = esp->aead;
170 alen = crypto_aead_authsize(aead);
171
172 tfclen = 0;
173 if (x->tfcpad) {
174 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
175 u32 padto;
176
177 padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
178 if (skb->len < padto)
179 tfclen = padto - skb->len;
180 }
181 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
182 clen = ALIGN(skb->len + 2 + tfclen, blksize);
183 if (esp->padlen)
184 clen = ALIGN(clen, esp->padlen);
185 plen = clen - skb->len - tfclen;
186
187 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
188 if (err < 0)
189 goto error;
190 nfrags = err;
191
192 assoclen = sizeof(*esph);
193 sglists = 1;
194 seqhilen = 0;
195
196 if (x->props.flags & XFRM_STATE_ESN) {
197 sglists += 2;
198 seqhilen += sizeof(__be32);
199 assoclen += seqhilen;
200 }
201
202 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
203 if (!tmp)
204 goto error;
205
206 seqhi = esp_tmp_seqhi(tmp);
207 iv = esp_tmp_iv(aead, tmp, seqhilen);
208 req = esp_tmp_givreq(aead, iv);
209 asg = esp_givreq_sg(aead, req);
210 sg = asg + sglists;
211
212 /* Fill padding... */
213 tail = skb_tail_pointer(trailer);
214 if (tfclen) {
215 memset(tail, 0, tfclen);
216 tail += tfclen;
217 }
218 do {
219 int i;
220 for (i = 0; i < plen - 2; i++)
221 tail[i] = i + 1;
222 } while (0);
223 tail[plen - 2] = plen - 2;
224 tail[plen - 1] = *skb_mac_header(skb);
225 pskb_put(skb, trailer, clen - skb->len + alen);
226
227 skb_push(skb, -skb_network_offset(skb));
228 esph = ip_esp_hdr(skb);
229 *skb_mac_header(skb) = IPPROTO_ESP;
230
231 esph->spi = x->id.spi;
232 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
233
234 sg_init_table(sg, nfrags);
235 skb_to_sgvec(skb, sg,
236 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
237 clen + alen);
238
239 if ((x->props.flags & XFRM_STATE_ESN)) {
240 sg_init_table(asg, 3);
241 sg_set_buf(asg, &esph->spi, sizeof(__be32));
242 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
243 sg_set_buf(asg + 1, seqhi, seqhilen);
244 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
245 } else
246 sg_init_one(asg, esph, sizeof(*esph));
247
248 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
249 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
250 aead_givcrypt_set_assoc(req, asg, assoclen);
251 aead_givcrypt_set_giv(req, esph->enc_data,
252 XFRM_SKB_CB(skb)->seq.output.low);
253
254 ESP_SKB_CB(skb)->tmp = tmp;
255 err = crypto_aead_givencrypt(req);
256 if (err == -EINPROGRESS)
257 goto error;
258
259 if (err == -EBUSY)
260 err = NET_XMIT_DROP;
261
262 kfree(tmp);
263
264error:
265 return err;
266}
267
268static int esp_input_done2(struct sk_buff *skb, int err)
269{
270 struct xfrm_state *x = xfrm_input_state(skb);
271 struct esp_data *esp = x->data;
272 struct crypto_aead *aead = esp->aead;
273 int alen = crypto_aead_authsize(aead);
274 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
275 int elen = skb->len - hlen;
276 int hdr_len = skb_network_header_len(skb);
277 int padlen;
278 u8 nexthdr[2];
279
280 kfree(ESP_SKB_CB(skb)->tmp);
281
282 if (unlikely(err))
283 goto out;
284
285 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
286 BUG();
287
288 err = -EINVAL;
289 padlen = nexthdr[0];
290 if (padlen + 2 + alen >= elen) {
291 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
292 "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
293 goto out;
294 }
295
296 /* ... check padding bits here. Silly. :-) */
297
298 pskb_trim(skb, skb->len - alen - padlen - 2);
299 __skb_pull(skb, hlen);
300 skb_set_transport_header(skb, -hdr_len);
301
302 err = nexthdr[1];
303
304 /* RFC4303: Drop dummy packets without any error */
305 if (err == IPPROTO_NONE)
306 err = -EINVAL;
307
308out:
309 return err;
310}
311
312static void esp_input_done(struct crypto_async_request *base, int err)
313{
314 struct sk_buff *skb = base->data;
315
316 xfrm_input_resume(skb, esp_input_done2(skb, err));
317}
318
319static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
320{
321 struct ip_esp_hdr *esph;
322 struct esp_data *esp = x->data;
323 struct crypto_aead *aead = esp->aead;
324 struct aead_request *req;
325 struct sk_buff *trailer;
326 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
327 int nfrags;
328 int assoclen;
329 int sglists;
330 int seqhilen;
331 int ret = 0;
332 void *tmp;
333 __be32 *seqhi;
334 u8 *iv;
335 struct scatterlist *sg;
336 struct scatterlist *asg;
337
338 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
339 ret = -EINVAL;
340 goto out;
341 }
342
343 if (elen <= 0) {
344 ret = -EINVAL;
345 goto out;
346 }
347
348 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
349 ret = -EINVAL;
350 goto out;
351 }
352
353 ret = -ENOMEM;
354
355 assoclen = sizeof(*esph);
356 sglists = 1;
357 seqhilen = 0;
358
359 if (x->props.flags & XFRM_STATE_ESN) {
360 sglists += 2;
361 seqhilen += sizeof(__be32);
362 assoclen += seqhilen;
363 }
364
365 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
366 if (!tmp)
367 goto out;
368
369 ESP_SKB_CB(skb)->tmp = tmp;
370 seqhi = esp_tmp_seqhi(tmp);
371 iv = esp_tmp_iv(aead, tmp, seqhilen);
372 req = esp_tmp_req(aead, iv);
373 asg = esp_req_sg(aead, req);
374 sg = asg + sglists;
375
376 skb->ip_summed = CHECKSUM_NONE;
377
378 esph = (struct ip_esp_hdr *)skb->data;
379
380 /* Get ivec. This can be wrong, check against another impls. */
381 iv = esph->enc_data;
382
383 sg_init_table(sg, nfrags);
384 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
385
386 if ((x->props.flags & XFRM_STATE_ESN)) {
387 sg_init_table(asg, 3);
388 sg_set_buf(asg, &esph->spi, sizeof(__be32));
389 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
390 sg_set_buf(asg + 1, seqhi, seqhilen);
391 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
392 } else
393 sg_init_one(asg, esph, sizeof(*esph));
394
395 aead_request_set_callback(req, 0, esp_input_done, skb);
396 aead_request_set_crypt(req, sg, sg, elen, iv);
397 aead_request_set_assoc(req, asg, assoclen);
398
399 ret = crypto_aead_decrypt(req);
400 if (ret == -EINPROGRESS)
401 goto out;
402
403 ret = esp_input_done2(skb, ret);
404
405out:
406 return ret;
407}
408
409static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
410{
411 struct esp_data *esp = x->data;
412 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
413 u32 align = max_t(u32, blksize, esp->padlen);
414 u32 rem;
415
416 mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
417 rem = mtu & (align - 1);
418 mtu &= ~(align - 1);
419
420 if (x->props.mode != XFRM_MODE_TUNNEL) {
421 u32 padsize = ((blksize - 1) & 7) + 1;
422 mtu -= blksize - padsize;
423 mtu += min_t(u32, blksize - padsize, rem);
424 }
425
426 return mtu - 2;
427}
428
429static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
430 u8 type, u8 code, int offset, __be32 info)
431{
432 struct net *net = dev_net(skb->dev);
433 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
434 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
435 struct xfrm_state *x;
436
437 if (type != ICMPV6_DEST_UNREACH &&
438 type != ICMPV6_PKT_TOOBIG)
439 return;
440
441 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
442 esph->spi, IPPROTO_ESP, AF_INET6);
443 if (!x)
444 return;
445 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%pI6\n",
446 ntohl(esph->spi), &iph->daddr);
447 xfrm_state_put(x);
448}
449
450static void esp6_destroy(struct xfrm_state *x)
451{
452 struct esp_data *esp = x->data;
453
454 if (!esp)
455 return;
456
457 crypto_free_aead(esp->aead);
458 kfree(esp);
459}
460
461static int esp_init_aead(struct xfrm_state *x)
462{
463 struct esp_data *esp = x->data;
464 struct crypto_aead *aead;
465 int err;
466
467 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
468 err = PTR_ERR(aead);
469 if (IS_ERR(aead))
470 goto error;
471
472 esp->aead = aead;
473
474 err = crypto_aead_setkey(aead, x->aead->alg_key,
475 (x->aead->alg_key_len + 7) / 8);
476 if (err)
477 goto error;
478
479 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
480 if (err)
481 goto error;
482
483error:
484 return err;
485}
486
487static int esp_init_authenc(struct xfrm_state *x)
488{
489 struct esp_data *esp = x->data;
490 struct crypto_aead *aead;
491 struct crypto_authenc_key_param *param;
492 struct rtattr *rta;
493 char *key;
494 char *p;
495 char authenc_name[CRYPTO_MAX_ALG_NAME];
496 unsigned int keylen;
497 int err;
498
499 err = -EINVAL;
500 if (x->ealg == NULL)
501 goto error;
502
503 err = -ENAMETOOLONG;
504
505 if ((x->props.flags & XFRM_STATE_ESN)) {
506 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
507 "authencesn(%s,%s)",
508 x->aalg ? x->aalg->alg_name : "digest_null",
509 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
510 goto error;
511 } else {
512 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
513 "authenc(%s,%s)",
514 x->aalg ? x->aalg->alg_name : "digest_null",
515 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
516 goto error;
517 }
518
519 aead = crypto_alloc_aead(authenc_name, 0, 0);
520 err = PTR_ERR(aead);
521 if (IS_ERR(aead))
522 goto error;
523
524 esp->aead = aead;
525
526 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
527 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
528 err = -ENOMEM;
529 key = kmalloc(keylen, GFP_KERNEL);
530 if (!key)
531 goto error;
532
533 p = key;
534 rta = (void *)p;
535 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
536 rta->rta_len = RTA_LENGTH(sizeof(*param));
537 param = RTA_DATA(rta);
538 p += RTA_SPACE(sizeof(*param));
539
540 if (x->aalg) {
541 struct xfrm_algo_desc *aalg_desc;
542
543 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
544 p += (x->aalg->alg_key_len + 7) / 8;
545
546 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
547 BUG_ON(!aalg_desc);
548
549 err = -EINVAL;
550 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
551 crypto_aead_authsize(aead)) {
552 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
553 x->aalg->alg_name,
554 crypto_aead_authsize(aead),
555 aalg_desc->uinfo.auth.icv_fullbits/8);
556 goto free_key;
557 }
558
559 err = crypto_aead_setauthsize(
560 aead, x->aalg->alg_trunc_len / 8);
561 if (err)
562 goto free_key;
563 }
564
565 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
566 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
567
568 err = crypto_aead_setkey(aead, key, keylen);
569
570free_key:
571 kfree(key);
572
573error:
574 return err;
575}
576
577static int esp6_init_state(struct xfrm_state *x)
578{
579 struct esp_data *esp;
580 struct crypto_aead *aead;
581 u32 align;
582 int err;
583
584 if (x->encap)
585 return -EINVAL;
586
587 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
588 if (esp == NULL)
589 return -ENOMEM;
590
591 x->data = esp;
592
593 if (x->aead)
594 err = esp_init_aead(x);
595 else
596 err = esp_init_authenc(x);
597
598 if (err)
599 goto error;
600
601 aead = esp->aead;
602
603 esp->padlen = 0;
604
605 x->props.header_len = sizeof(struct ip_esp_hdr) +
606 crypto_aead_ivsize(aead);
607 switch (x->props.mode) {
608 case XFRM_MODE_BEET:
609 if (x->sel.family != AF_INET6)
610 x->props.header_len += IPV4_BEET_PHMAXLEN +
611 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
612 break;
613 case XFRM_MODE_TRANSPORT:
614 break;
615 case XFRM_MODE_TUNNEL:
616 x->props.header_len += sizeof(struct ipv6hdr);
617 break;
618 default:
619 goto error;
620 }
621
622 align = ALIGN(crypto_aead_blocksize(aead), 4);
623 if (esp->padlen)
624 align = max_t(u32, align, esp->padlen);
625 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
626
627error:
628 return err;
629}
630
631static const struct xfrm_type esp6_type =
632{
633 .description = "ESP6",
634 .owner = THIS_MODULE,
635 .proto = IPPROTO_ESP,
636 .flags = XFRM_TYPE_REPLAY_PROT,
637 .init_state = esp6_init_state,
638 .destructor = esp6_destroy,
639 .get_mtu = esp6_get_mtu,
640 .input = esp6_input,
641 .output = esp6_output,
642 .hdr_offset = xfrm6_find_1stfragopt,
643};
644
645static const struct inet6_protocol esp6_protocol = {
646 .handler = xfrm6_rcv,
647 .err_handler = esp6_err,
648 .flags = INET6_PROTO_NOPOLICY,
649};
650
651static int __init esp6_init(void)
652{
653 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
654 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
655 return -EAGAIN;
656 }
657 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
658 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
659 xfrm_unregister_type(&esp6_type, AF_INET6);
660 return -EAGAIN;
661 }
662
663 return 0;
664}
665
666static void __exit esp6_fini(void)
667{
668 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
669 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
670 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
671 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
672}
673
674module_init(esp6_init);
675module_exit(esp6_fini);
676
677MODULE_LICENSE("GPL");
678MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
1/*
2 * Copyright (C)2002 USAGI/WIDE Project
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, 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_givcrypt_request) + crypto_aead_reqsize(aead);
80 len = ALIGN(len, __alignof__(struct scatterlist));
81
82 len += sizeof(struct scatterlist) * nfrags;
83
84 return kmalloc(len, GFP_ATOMIC);
85}
86
87static inline __be32 *esp_tmp_seqhi(void *tmp)
88{
89 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
90}
91
92static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
93{
94 return crypto_aead_ivsize(aead) ?
95 PTR_ALIGN((u8 *)tmp + seqhilen,
96 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
97}
98
99static inline struct aead_givcrypt_request *esp_tmp_givreq(
100 struct crypto_aead *aead, u8 *iv)
101{
102 struct aead_givcrypt_request *req;
103
104 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
105 crypto_tfm_ctx_alignment());
106 aead_givcrypt_set_tfm(req, aead);
107 return req;
108}
109
110static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
111{
112 struct aead_request *req;
113
114 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
115 crypto_tfm_ctx_alignment());
116 aead_request_set_tfm(req, aead);
117 return req;
118}
119
120static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
121 struct aead_request *req)
122{
123 return (void *)ALIGN((unsigned long)(req + 1) +
124 crypto_aead_reqsize(aead),
125 __alignof__(struct scatterlist));
126}
127
128static inline struct scatterlist *esp_givreq_sg(
129 struct crypto_aead *aead, struct aead_givcrypt_request *req)
130{
131 return (void *)ALIGN((unsigned long)(req + 1) +
132 crypto_aead_reqsize(aead),
133 __alignof__(struct scatterlist));
134}
135
136static void esp_output_done(struct crypto_async_request *base, int err)
137{
138 struct sk_buff *skb = base->data;
139
140 kfree(ESP_SKB_CB(skb)->tmp);
141 xfrm_output_resume(skb, err);
142}
143
144static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
145{
146 int err;
147 struct ip_esp_hdr *esph;
148 struct crypto_aead *aead;
149 struct aead_givcrypt_request *req;
150 struct scatterlist *sg;
151 struct scatterlist *asg;
152 struct sk_buff *trailer;
153 void *tmp;
154 int blksize;
155 int clen;
156 int alen;
157 int plen;
158 int tfclen;
159 int nfrags;
160 int assoclen;
161 int sglists;
162 int seqhilen;
163 u8 *iv;
164 u8 *tail;
165 __be32 *seqhi;
166
167 /* skb is pure payload to encrypt */
168 aead = x->data;
169 alen = crypto_aead_authsize(aead);
170
171 tfclen = 0;
172 if (x->tfcpad) {
173 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
174 u32 padto;
175
176 padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
177 if (skb->len < padto)
178 tfclen = padto - skb->len;
179 }
180 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
181 clen = ALIGN(skb->len + 2 + tfclen, blksize);
182 plen = clen - skb->len - tfclen;
183
184 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
185 if (err < 0)
186 goto error;
187 nfrags = err;
188
189 assoclen = sizeof(*esph);
190 sglists = 1;
191 seqhilen = 0;
192
193 if (x->props.flags & XFRM_STATE_ESN) {
194 sglists += 2;
195 seqhilen += sizeof(__be32);
196 assoclen += seqhilen;
197 }
198
199 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
200 if (!tmp) {
201 err = -ENOMEM;
202 goto error;
203 }
204
205 seqhi = esp_tmp_seqhi(tmp);
206 iv = esp_tmp_iv(aead, tmp, seqhilen);
207 req = esp_tmp_givreq(aead, iv);
208 asg = esp_givreq_sg(aead, req);
209 sg = asg + sglists;
210
211 /* Fill padding... */
212 tail = skb_tail_pointer(trailer);
213 if (tfclen) {
214 memset(tail, 0, tfclen);
215 tail += tfclen;
216 }
217 do {
218 int i;
219 for (i = 0; i < plen - 2; i++)
220 tail[i] = i + 1;
221 } while (0);
222 tail[plen - 2] = plen - 2;
223 tail[plen - 1] = *skb_mac_header(skb);
224 pskb_put(skb, trailer, clen - skb->len + alen);
225
226 skb_push(skb, -skb_network_offset(skb));
227 esph = ip_esp_hdr(skb);
228 *skb_mac_header(skb) = IPPROTO_ESP;
229
230 esph->spi = x->id.spi;
231 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
232
233 sg_init_table(sg, nfrags);
234 skb_to_sgvec(skb, sg,
235 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
236 clen + alen);
237
238 if ((x->props.flags & XFRM_STATE_ESN)) {
239 sg_init_table(asg, 3);
240 sg_set_buf(asg, &esph->spi, sizeof(__be32));
241 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
242 sg_set_buf(asg + 1, seqhi, seqhilen);
243 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
244 } else
245 sg_init_one(asg, esph, sizeof(*esph));
246
247 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
248 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
249 aead_givcrypt_set_assoc(req, asg, assoclen);
250 aead_givcrypt_set_giv(req, esph->enc_data,
251 XFRM_SKB_CB(skb)->seq.output.low);
252
253 ESP_SKB_CB(skb)->tmp = tmp;
254 err = crypto_aead_givencrypt(req);
255 if (err == -EINPROGRESS)
256 goto error;
257
258 if (err == -EBUSY)
259 err = NET_XMIT_DROP;
260
261 kfree(tmp);
262
263error:
264 return err;
265}
266
267static int esp_input_done2(struct sk_buff *skb, int err)
268{
269 struct xfrm_state *x = xfrm_input_state(skb);
270 struct crypto_aead *aead = x->data;
271 int alen = crypto_aead_authsize(aead);
272 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
273 int elen = skb->len - hlen;
274 int hdr_len = skb_network_header_len(skb);
275 int padlen;
276 u8 nexthdr[2];
277
278 kfree(ESP_SKB_CB(skb)->tmp);
279
280 if (unlikely(err))
281 goto out;
282
283 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
284 BUG();
285
286 err = -EINVAL;
287 padlen = nexthdr[0];
288 if (padlen + 2 + alen >= elen) {
289 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
290 "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
291 goto out;
292 }
293
294 /* ... check padding bits here. Silly. :-) */
295
296 pskb_trim(skb, skb->len - alen - padlen - 2);
297 __skb_pull(skb, hlen);
298 if (x->props.mode == XFRM_MODE_TUNNEL)
299 skb_reset_transport_header(skb);
300 else
301 skb_set_transport_header(skb, -hdr_len);
302
303 err = nexthdr[1];
304
305 /* RFC4303: Drop dummy packets without any error */
306 if (err == IPPROTO_NONE)
307 err = -EINVAL;
308
309out:
310 return err;
311}
312
313static void esp_input_done(struct crypto_async_request *base, int err)
314{
315 struct sk_buff *skb = base->data;
316
317 xfrm_input_resume(skb, esp_input_done2(skb, err));
318}
319
320static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
321{
322 struct ip_esp_hdr *esph;
323 struct crypto_aead *aead = x->data;
324 struct aead_request *req;
325 struct sk_buff *trailer;
326 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
327 int nfrags;
328 int assoclen;
329 int sglists;
330 int seqhilen;
331 int ret = 0;
332 void *tmp;
333 __be32 *seqhi;
334 u8 *iv;
335 struct scatterlist *sg;
336 struct scatterlist *asg;
337
338 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
339 ret = -EINVAL;
340 goto out;
341 }
342
343 if (elen <= 0) {
344 ret = -EINVAL;
345 goto out;
346 }
347
348 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
349 ret = -EINVAL;
350 goto out;
351 }
352
353 ret = -ENOMEM;
354
355 assoclen = sizeof(*esph);
356 sglists = 1;
357 seqhilen = 0;
358
359 if (x->props.flags & XFRM_STATE_ESN) {
360 sglists += 2;
361 seqhilen += sizeof(__be32);
362 assoclen += seqhilen;
363 }
364
365 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
366 if (!tmp)
367 goto out;
368
369 ESP_SKB_CB(skb)->tmp = tmp;
370 seqhi = esp_tmp_seqhi(tmp);
371 iv = esp_tmp_iv(aead, tmp, seqhilen);
372 req = esp_tmp_req(aead, iv);
373 asg = esp_req_sg(aead, req);
374 sg = asg + sglists;
375
376 skb->ip_summed = CHECKSUM_NONE;
377
378 esph = (struct ip_esp_hdr *)skb->data;
379
380 /* Get ivec. This can be wrong, check against another impls. */
381 iv = esph->enc_data;
382
383 sg_init_table(sg, nfrags);
384 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
385
386 if ((x->props.flags & XFRM_STATE_ESN)) {
387 sg_init_table(asg, 3);
388 sg_set_buf(asg, &esph->spi, sizeof(__be32));
389 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
390 sg_set_buf(asg + 1, seqhi, seqhilen);
391 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
392 } else
393 sg_init_one(asg, esph, sizeof(*esph));
394
395 aead_request_set_callback(req, 0, esp_input_done, skb);
396 aead_request_set_crypt(req, sg, sg, elen, iv);
397 aead_request_set_assoc(req, asg, assoclen);
398
399 ret = crypto_aead_decrypt(req);
400 if (ret == -EINPROGRESS)
401 goto out;
402
403 ret = esp_input_done2(skb, ret);
404
405out:
406 return ret;
407}
408
409static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
410{
411 struct crypto_aead *aead = x->data;
412 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
413 unsigned int net_adj;
414
415 if (x->props.mode != XFRM_MODE_TUNNEL)
416 net_adj = sizeof(struct ipv6hdr);
417 else
418 net_adj = 0;
419
420 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
421 net_adj) & ~(blksize - 1)) + net_adj - 2;
422}
423
424static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
425 u8 type, u8 code, int offset, __be32 info)
426{
427 struct net *net = dev_net(skb->dev);
428 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
429 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
430 struct xfrm_state *x;
431
432 if (type != ICMPV6_PKT_TOOBIG &&
433 type != NDISC_REDIRECT)
434 return 0;
435
436 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
437 esph->spi, IPPROTO_ESP, AF_INET6);
438 if (!x)
439 return 0;
440
441 if (type == NDISC_REDIRECT)
442 ip6_redirect(skb, net, skb->dev->ifindex, 0);
443 else
444 ip6_update_pmtu(skb, net, info, 0, 0);
445 xfrm_state_put(x);
446
447 return 0;
448}
449
450static void esp6_destroy(struct xfrm_state *x)
451{
452 struct crypto_aead *aead = x->data;
453
454 if (!aead)
455 return;
456
457 crypto_free_aead(aead);
458}
459
460static int esp_init_aead(struct xfrm_state *x)
461{
462 struct crypto_aead *aead;
463 int err;
464
465 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
466 err = PTR_ERR(aead);
467 if (IS_ERR(aead))
468 goto error;
469
470 x->data = aead;
471
472 err = crypto_aead_setkey(aead, x->aead->alg_key,
473 (x->aead->alg_key_len + 7) / 8);
474 if (err)
475 goto error;
476
477 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
478 if (err)
479 goto error;
480
481error:
482 return err;
483}
484
485static int esp_init_authenc(struct xfrm_state *x)
486{
487 struct crypto_aead *aead;
488 struct crypto_authenc_key_param *param;
489 struct rtattr *rta;
490 char *key;
491 char *p;
492 char authenc_name[CRYPTO_MAX_ALG_NAME];
493 unsigned int keylen;
494 int err;
495
496 err = -EINVAL;
497 if (x->ealg == NULL)
498 goto error;
499
500 err = -ENAMETOOLONG;
501
502 if ((x->props.flags & XFRM_STATE_ESN)) {
503 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
504 "authencesn(%s,%s)",
505 x->aalg ? x->aalg->alg_name : "digest_null",
506 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
507 goto error;
508 } else {
509 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
510 "authenc(%s,%s)",
511 x->aalg ? x->aalg->alg_name : "digest_null",
512 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
513 goto error;
514 }
515
516 aead = crypto_alloc_aead(authenc_name, 0, 0);
517 err = PTR_ERR(aead);
518 if (IS_ERR(aead))
519 goto error;
520
521 x->data = aead;
522
523 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
524 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
525 err = -ENOMEM;
526 key = kmalloc(keylen, GFP_KERNEL);
527 if (!key)
528 goto error;
529
530 p = key;
531 rta = (void *)p;
532 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
533 rta->rta_len = RTA_LENGTH(sizeof(*param));
534 param = RTA_DATA(rta);
535 p += RTA_SPACE(sizeof(*param));
536
537 if (x->aalg) {
538 struct xfrm_algo_desc *aalg_desc;
539
540 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
541 p += (x->aalg->alg_key_len + 7) / 8;
542
543 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
544 BUG_ON(!aalg_desc);
545
546 err = -EINVAL;
547 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
548 crypto_aead_authsize(aead)) {
549 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
550 x->aalg->alg_name,
551 crypto_aead_authsize(aead),
552 aalg_desc->uinfo.auth.icv_fullbits/8);
553 goto free_key;
554 }
555
556 err = crypto_aead_setauthsize(
557 aead, x->aalg->alg_trunc_len / 8);
558 if (err)
559 goto free_key;
560 }
561
562 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
563 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
564
565 err = crypto_aead_setkey(aead, key, keylen);
566
567free_key:
568 kfree(key);
569
570error:
571 return err;
572}
573
574static int esp6_init_state(struct xfrm_state *x)
575{
576 struct crypto_aead *aead;
577 u32 align;
578 int err;
579
580 if (x->encap)
581 return -EINVAL;
582
583 x->data = NULL;
584
585 if (x->aead)
586 err = esp_init_aead(x);
587 else
588 err = esp_init_authenc(x);
589
590 if (err)
591 goto error;
592
593 aead = x->data;
594
595 x->props.header_len = sizeof(struct ip_esp_hdr) +
596 crypto_aead_ivsize(aead);
597 switch (x->props.mode) {
598 case XFRM_MODE_BEET:
599 if (x->sel.family != AF_INET6)
600 x->props.header_len += IPV4_BEET_PHMAXLEN +
601 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
602 break;
603 case XFRM_MODE_TRANSPORT:
604 break;
605 case XFRM_MODE_TUNNEL:
606 x->props.header_len += sizeof(struct ipv6hdr);
607 break;
608 default:
609 goto error;
610 }
611
612 align = ALIGN(crypto_aead_blocksize(aead), 4);
613 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
614
615error:
616 return err;
617}
618
619static int esp6_rcv_cb(struct sk_buff *skb, int err)
620{
621 return 0;
622}
623
624static const struct xfrm_type esp6_type =
625{
626 .description = "ESP6",
627 .owner = THIS_MODULE,
628 .proto = IPPROTO_ESP,
629 .flags = XFRM_TYPE_REPLAY_PROT,
630 .init_state = esp6_init_state,
631 .destructor = esp6_destroy,
632 .get_mtu = esp6_get_mtu,
633 .input = esp6_input,
634 .output = esp6_output,
635 .hdr_offset = xfrm6_find_1stfragopt,
636};
637
638static struct xfrm6_protocol esp6_protocol = {
639 .handler = xfrm6_rcv,
640 .cb_handler = esp6_rcv_cb,
641 .err_handler = esp6_err,
642 .priority = 0,
643};
644
645static int __init esp6_init(void)
646{
647 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
648 pr_info("%s: can't add xfrm type\n", __func__);
649 return -EAGAIN;
650 }
651 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
652 pr_info("%s: can't add protocol\n", __func__);
653 xfrm_unregister_type(&esp6_type, AF_INET6);
654 return -EAGAIN;
655 }
656
657 return 0;
658}
659
660static void __exit esp6_fini(void)
661{
662 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
663 pr_info("%s: can't remove protocol\n", __func__);
664 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
665 pr_info("%s: can't remove xfrm type\n", __func__);
666}
667
668module_init(esp6_init);
669module_exit(esp6_fini);
670
671MODULE_LICENSE("GPL");
672MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);