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esp6: Add support for IPsec extended sequence numbers
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / ipv6 / esp6.c
blob5aa8ec88f1946296ce4f776f8927f764cf4edbc1
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
45 struct 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
52 static 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 */
63 static 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
85 static inline __be32 *esp_tmp_seqhi(void *tmp)
86 {
87 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
88 }
89
90 static 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
97 static 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
108 static 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
118 static 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
126 static 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
134 static 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
142 static 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
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 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
308 out:
309 return err;
310 }
311
312 static 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
319 static 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 + 1;
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
405 out:
406 return ret;
407 }
408
409 static 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
429 static 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 struct ipv6hdr *iph = (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, (xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
442 if (!x)
443 return;
444 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%pI6\n",
445 ntohl(esph->spi), &iph->daddr);
446 xfrm_state_put(x);
447 }
448
449 static void esp6_destroy(struct xfrm_state *x)
450 {
451 struct esp_data *esp = x->data;
452
453 if (!esp)
454 return;
455
456 crypto_free_aead(esp->aead);
457 kfree(esp);
458 }
459
460 static int esp_init_aead(struct xfrm_state *x)
461 {
462 struct esp_data *esp = x->data;
463 struct crypto_aead *aead;
464 int err;
465
466 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
467 err = PTR_ERR(aead);
468 if (IS_ERR(aead))
469 goto error;
470
471 esp->aead = aead;
472
473 err = crypto_aead_setkey(aead, x->aead->alg_key,
474 (x->aead->alg_key_len + 7) / 8);
475 if (err)
476 goto error;
477
478 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
479 if (err)
480 goto error;
481
482 error:
483 return err;
484 }
485
486 static int esp_init_authenc(struct xfrm_state *x)
487 {
488 struct esp_data *esp = x->data;
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 == NULL)
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 esp->aead = 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 NETDEBUG(KERN_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 esp_data *esp;
579 struct crypto_aead *aead;
580 u32 align;
581 int err;
582
583 if (x->encap)
584 return -EINVAL;
585
586 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
587 if (esp == NULL)
588 return -ENOMEM;
589
590 x->data = esp;
591
592 if (x->aead)
593 err = esp_init_aead(x);
594 else
595 err = esp_init_authenc(x);
596
597 if (err)
598 goto error;
599
600 aead = esp->aead;
601
602 esp->padlen = 0;
603
604 x->props.header_len = sizeof(struct ip_esp_hdr) +
605 crypto_aead_ivsize(aead);
606 switch (x->props.mode) {
607 case XFRM_MODE_BEET:
608 if (x->sel.family != AF_INET6)
609 x->props.header_len += IPV4_BEET_PHMAXLEN +
610 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
611 break;
612 case XFRM_MODE_TRANSPORT:
613 break;
614 case XFRM_MODE_TUNNEL:
615 x->props.header_len += sizeof(struct ipv6hdr);
616 break;
617 default:
618 goto error;
619 }
620
621 align = ALIGN(crypto_aead_blocksize(aead), 4);
622 if (esp->padlen)
623 align = max_t(u32, align, esp->padlen);
624 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
625
626 error:
627 return err;
628 }
629
630 static const struct xfrm_type esp6_type =
631 {
632 .description = "ESP6",
633 .owner = THIS_MODULE,
634 .proto = IPPROTO_ESP,
635 .flags = XFRM_TYPE_REPLAY_PROT,
636 .init_state = esp6_init_state,
637 .destructor = esp6_destroy,
638 .get_mtu = esp6_get_mtu,
639 .input = esp6_input,
640 .output = esp6_output,
641 .hdr_offset = xfrm6_find_1stfragopt,
642 };
643
644 static const struct inet6_protocol esp6_protocol = {
645 .handler = xfrm6_rcv,
646 .err_handler = esp6_err,
647 .flags = INET6_PROTO_NOPOLICY,
648 };
649
650 static int __init esp6_init(void)
651 {
652 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
653 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
654 return -EAGAIN;
655 }
656 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
657 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
658 xfrm_unregister_type(&esp6_type, AF_INET6);
659 return -EAGAIN;
660 }
661
662 return 0;
663 }
664
665 static void __exit esp6_fini(void)
666 {
667 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
668 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
669 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
670 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
671 }
672
673 module_init(esp6_init);
674 module_exit(esp6_fini);
675
676 MODULE_LICENSE("GPL");
677 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
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