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Linux 4.1.16
[linux/fpc-iii.git] / net / ipv6 / esp6.c
blob7c07ce36aae2a5b9cc14cb5a883327b7230b38ee
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
47 struct 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
54 static 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 */
65 static 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
87 static inline __be32 *esp_tmp_seqhi(void *tmp)
88 {
89 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
90 }
91
92 static 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
99 static 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
110 static 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
120 static 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
128 static 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
136 static 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
144 static 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 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
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
264 error:
265 return err;
266 }
267
268 static int esp_input_done2(struct sk_buff *skb, int err)
269 {
270 struct xfrm_state *x = xfrm_input_state(skb);
271 struct crypto_aead *aead = x->data;
272 int alen = crypto_aead_authsize(aead);
273 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
274 int elen = skb->len - hlen;
275 int hdr_len = skb_network_header_len(skb);
276 int padlen;
277 u8 nexthdr[2];
278
279 kfree(ESP_SKB_CB(skb)->tmp);
280
281 if (unlikely(err))
282 goto out;
283
284 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
285 BUG();
286
287 err = -EINVAL;
288 padlen = nexthdr[0];
289 if (padlen + 2 + alen >= elen) {
290 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
291 padlen + 2, elen - alen);
292 goto out;
293 }
294
295 /* ... check padding bits here. Silly. :-) */
296
297 pskb_trim(skb, skb->len - alen - padlen - 2);
298 __skb_pull(skb, hlen);
299 if (x->props.mode == XFRM_MODE_TUNNEL)
300 skb_reset_transport_header(skb);
301 else
302 skb_set_transport_header(skb, -hdr_len);
303
304 err = nexthdr[1];
305
306 /* RFC4303: Drop dummy packets without any error */
307 if (err == IPPROTO_NONE)
308 err = -EINVAL;
309
310 out:
311 return err;
312 }
313
314 static void esp_input_done(struct crypto_async_request *base, int err)
315 {
316 struct sk_buff *skb = base->data;
317
318 xfrm_input_resume(skb, esp_input_done2(skb, err));
319 }
320
321 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
322 {
323 struct ip_esp_hdr *esph;
324 struct crypto_aead *aead = x->data;
325 struct aead_request *req;
326 struct sk_buff *trailer;
327 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
328 int nfrags;
329 int assoclen;
330 int sglists;
331 int seqhilen;
332 int ret = 0;
333 void *tmp;
334 __be32 *seqhi;
335 u8 *iv;
336 struct scatterlist *sg;
337 struct scatterlist *asg;
338
339 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
340 ret = -EINVAL;
341 goto out;
342 }
343
344 if (elen <= 0) {
345 ret = -EINVAL;
346 goto out;
347 }
348
349 nfrags = skb_cow_data(skb, 0, &trailer);
350 if (nfrags < 0) {
351 ret = -EINVAL;
352 goto out;
353 }
354
355 ret = -ENOMEM;
356
357 assoclen = sizeof(*esph);
358 sglists = 1;
359 seqhilen = 0;
360
361 if (x->props.flags & XFRM_STATE_ESN) {
362 sglists += 2;
363 seqhilen += sizeof(__be32);
364 assoclen += seqhilen;
365 }
366
367 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
368 if (!tmp)
369 goto out;
370
371 ESP_SKB_CB(skb)->tmp = tmp;
372 seqhi = esp_tmp_seqhi(tmp);
373 iv = esp_tmp_iv(aead, tmp, seqhilen);
374 req = esp_tmp_req(aead, iv);
375 asg = esp_req_sg(aead, req);
376 sg = asg + sglists;
377
378 skb->ip_summed = CHECKSUM_NONE;
379
380 esph = (struct ip_esp_hdr *)skb->data;
381
382 /* Get ivec. This can be wrong, check against another impls. */
383 iv = esph->enc_data;
384
385 sg_init_table(sg, nfrags);
386 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
387
388 if ((x->props.flags & XFRM_STATE_ESN)) {
389 sg_init_table(asg, 3);
390 sg_set_buf(asg, &esph->spi, sizeof(__be32));
391 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
392 sg_set_buf(asg + 1, seqhi, seqhilen);
393 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
394 } else
395 sg_init_one(asg, esph, sizeof(*esph));
396
397 aead_request_set_callback(req, 0, esp_input_done, skb);
398 aead_request_set_crypt(req, sg, sg, elen, iv);
399 aead_request_set_assoc(req, asg, assoclen);
400
401 ret = crypto_aead_decrypt(req);
402 if (ret == -EINPROGRESS)
403 goto out;
404
405 ret = esp_input_done2(skb, ret);
406
407 out:
408 return ret;
409 }
410
411 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
412 {
413 struct crypto_aead *aead = x->data;
414 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
415 unsigned int net_adj;
416
417 if (x->props.mode != XFRM_MODE_TUNNEL)
418 net_adj = sizeof(struct ipv6hdr);
419 else
420 net_adj = 0;
421
422 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
423 net_adj) & ~(blksize - 1)) + net_adj - 2;
424 }
425
426 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
427 u8 type, u8 code, int offset, __be32 info)
428 {
429 struct net *net = dev_net(skb->dev);
430 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
431 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
432 struct xfrm_state *x;
433
434 if (type != ICMPV6_PKT_TOOBIG &&
435 type != NDISC_REDIRECT)
436 return 0;
437
438 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
439 esph->spi, IPPROTO_ESP, AF_INET6);
440 if (!x)
441 return 0;
442
443 if (type == NDISC_REDIRECT)
444 ip6_redirect(skb, net, skb->dev->ifindex, 0);
445 else
446 ip6_update_pmtu(skb, net, info, 0, 0);
447 xfrm_state_put(x);
448
449 return 0;
450 }
451
452 static void esp6_destroy(struct xfrm_state *x)
453 {
454 struct crypto_aead *aead = x->data;
455
456 if (!aead)
457 return;
458
459 crypto_free_aead(aead);
460 }
461
462 static int esp_init_aead(struct xfrm_state *x)
463 {
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 x->data = 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
483 error:
484 return err;
485 }
486
487 static int esp_init_authenc(struct xfrm_state *x)
488 {
489 struct crypto_aead *aead;
490 struct crypto_authenc_key_param *param;
491 struct rtattr *rta;
492 char *key;
493 char *p;
494 char authenc_name[CRYPTO_MAX_ALG_NAME];
495 unsigned int keylen;
496 int err;
497
498 err = -EINVAL;
499 if (!x->ealg)
500 goto error;
501
502 err = -ENAMETOOLONG;
503
504 if ((x->props.flags & XFRM_STATE_ESN)) {
505 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
506 "authencesn(%s,%s)",
507 x->aalg ? x->aalg->alg_name : "digest_null",
508 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
509 goto error;
510 } else {
511 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
512 "authenc(%s,%s)",
513 x->aalg ? x->aalg->alg_name : "digest_null",
514 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
515 goto error;
516 }
517
518 aead = crypto_alloc_aead(authenc_name, 0, 0);
519 err = PTR_ERR(aead);
520 if (IS_ERR(aead))
521 goto error;
522
523 x->data = aead;
524
525 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
526 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
527 err = -ENOMEM;
528 key = kmalloc(keylen, GFP_KERNEL);
529 if (!key)
530 goto error;
531
532 p = key;
533 rta = (void *)p;
534 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
535 rta->rta_len = RTA_LENGTH(sizeof(*param));
536 param = RTA_DATA(rta);
537 p += RTA_SPACE(sizeof(*param));
538
539 if (x->aalg) {
540 struct xfrm_algo_desc *aalg_desc;
541
542 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
543 p += (x->aalg->alg_key_len + 7) / 8;
544
545 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
546 BUG_ON(!aalg_desc);
547
548 err = -EINVAL;
549 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
550 crypto_aead_authsize(aead)) {
551 pr_info("ESP: %s digestsize %u != %hu\n",
552 x->aalg->alg_name,
553 crypto_aead_authsize(aead),
554 aalg_desc->uinfo.auth.icv_fullbits / 8);
555 goto free_key;
556 }
557
558 err = crypto_aead_setauthsize(
559 aead, x->aalg->alg_trunc_len / 8);
560 if (err)
561 goto free_key;
562 }
563
564 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
565 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
566
567 err = crypto_aead_setkey(aead, key, keylen);
568
569 free_key:
570 kfree(key);
571
572 error:
573 return err;
574 }
575
576 static int esp6_init_state(struct xfrm_state *x)
577 {
578 struct crypto_aead *aead;
579 u32 align;
580 int err;
581
582 if (x->encap)
583 return -EINVAL;
584
585 x->data = NULL;
586
587 if (x->aead)
588 err = esp_init_aead(x);
589 else
590 err = esp_init_authenc(x);
591
592 if (err)
593 goto error;
594
595 aead = x->data;
596
597 x->props.header_len = sizeof(struct ip_esp_hdr) +
598 crypto_aead_ivsize(aead);
599 switch (x->props.mode) {
600 case XFRM_MODE_BEET:
601 if (x->sel.family != AF_INET6)
602 x->props.header_len += IPV4_BEET_PHMAXLEN +
603 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
604 break;
605 case XFRM_MODE_TRANSPORT:
606 break;
607 case XFRM_MODE_TUNNEL:
608 x->props.header_len += sizeof(struct ipv6hdr);
609 break;
610 default:
611 goto error;
612 }
613
614 align = ALIGN(crypto_aead_blocksize(aead), 4);
615 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
616
617 error:
618 return err;
619 }
620
621 static int esp6_rcv_cb(struct sk_buff *skb, int err)
622 {
623 return 0;
624 }
625
626 static const struct xfrm_type esp6_type = {
627 .description = "ESP6",
628 .owner = THIS_MODULE,
629 .proto = IPPROTO_ESP,
630 .flags = XFRM_TYPE_REPLAY_PROT,
631 .init_state = esp6_init_state,
632 .destructor = esp6_destroy,
633 .get_mtu = esp6_get_mtu,
634 .input = esp6_input,
635 .output = esp6_output,
636 .hdr_offset = xfrm6_find_1stfragopt,
637 };
638
639 static struct xfrm6_protocol esp6_protocol = {
640 .handler = xfrm6_rcv,
641 .cb_handler = esp6_rcv_cb,
642 .err_handler = esp6_err,
643 .priority = 0,
644 };
645
646 static int __init esp6_init(void)
647 {
648 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
649 pr_info("%s: can't add xfrm type\n", __func__);
650 return -EAGAIN;
651 }
652 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
653 pr_info("%s: can't add protocol\n", __func__);
654 xfrm_unregister_type(&esp6_type, AF_INET6);
655 return -EAGAIN;
656 }
657
658 return 0;
659 }
660
661 static void __exit esp6_fini(void)
662 {
663 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
664 pr_info("%s: can't remove protocol\n", __func__);
665 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
666 pr_info("%s: can't remove xfrm type\n", __func__);
667 }
668
669 module_init(esp6_init);
670 module_exit(esp6_fini);
671
672 MODULE_LICENSE("GPL");
673 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
Linux with added FPC-III support