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iovec: make sure the caller actually wants anything in memcpy_fromiovecend
[linux/fpc-iii.git] / net / ipv6 / esp6.c
blobaf597c73ebe9b6bc53f5ae0eb4c91a268a66e47d
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 /*
53 * Allocate an AEAD request structure with extra space for SG and IV.
54 *
55 * For alignment considerations the IV is placed at the front, followed
56 * by the request and finally the SG list.
57 *
58 * TODO: Use spare space in skb for this where possible.
59 */
60 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags)
61 {
62 unsigned int len;
63
64 len = crypto_aead_ivsize(aead);
65 if (len) {
66 len += crypto_aead_alignmask(aead) &
67 ~(crypto_tfm_ctx_alignment() - 1);
68 len = ALIGN(len, crypto_tfm_ctx_alignment());
69 }
70
71 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
72 len = ALIGN(len, __alignof__(struct scatterlist));
73
74 len += sizeof(struct scatterlist) * nfrags;
75
76 return kmalloc(len, GFP_ATOMIC);
77 }
78
79 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp)
80 {
81 return crypto_aead_ivsize(aead) ?
82 PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
83 }
84
85 static inline struct aead_givcrypt_request *esp_tmp_givreq(
86 struct crypto_aead *aead, u8 *iv)
87 {
88 struct aead_givcrypt_request *req;
89
90 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
91 crypto_tfm_ctx_alignment());
92 aead_givcrypt_set_tfm(req, aead);
93 return req;
94 }
95
96 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
97 {
98 struct aead_request *req;
99
100 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
101 crypto_tfm_ctx_alignment());
102 aead_request_set_tfm(req, aead);
103 return req;
104 }
105
106 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
107 struct aead_request *req)
108 {
109 return (void *)ALIGN((unsigned long)(req + 1) +
110 crypto_aead_reqsize(aead),
111 __alignof__(struct scatterlist));
112 }
113
114 static inline struct scatterlist *esp_givreq_sg(
115 struct crypto_aead *aead, struct aead_givcrypt_request *req)
116 {
117 return (void *)ALIGN((unsigned long)(req + 1) +
118 crypto_aead_reqsize(aead),
119 __alignof__(struct scatterlist));
120 }
121
122 static void esp_output_done(struct crypto_async_request *base, int err)
123 {
124 struct sk_buff *skb = base->data;
125
126 kfree(ESP_SKB_CB(skb)->tmp);
127 xfrm_output_resume(skb, err);
128 }
129
130 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
131 {
132 int err;
133 struct ip_esp_hdr *esph;
134 struct crypto_aead *aead;
135 struct aead_givcrypt_request *req;
136 struct scatterlist *sg;
137 struct scatterlist *asg;
138 struct sk_buff *trailer;
139 void *tmp;
140 int blksize;
141 int clen;
142 int alen;
143 int nfrags;
144 u8 *iv;
145 u8 *tail;
146 struct esp_data *esp = x->data;
147
148 /* skb is pure payload to encrypt */
149 err = -ENOMEM;
150
151 /* Round to block size */
152 clen = skb->len;
153
154 aead = esp->aead;
155 alen = crypto_aead_authsize(aead);
156
157 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
158 clen = ALIGN(clen + 2, blksize);
159 if (esp->padlen)
160 clen = ALIGN(clen, esp->padlen);
161
162 if ((err = skb_cow_data(skb, clen - skb->len + alen, &trailer)) < 0)
163 goto error;
164 nfrags = err;
165
166 tmp = esp_alloc_tmp(aead, nfrags + 1);
167 if (!tmp)
168 goto error;
169
170 iv = esp_tmp_iv(aead, tmp);
171 req = esp_tmp_givreq(aead, iv);
172 asg = esp_givreq_sg(aead, req);
173 sg = asg + 1;
174
175 /* Fill padding... */
176 tail = skb_tail_pointer(trailer);
177 do {
178 int i;
179 for (i=0; i<clen-skb->len - 2; i++)
180 tail[i] = i + 1;
181 } while (0);
182 tail[clen-skb->len - 2] = (clen - skb->len) - 2;
183 tail[clen - skb->len - 1] = *skb_mac_header(skb);
184 pskb_put(skb, trailer, clen - skb->len + alen);
185
186 skb_push(skb, -skb_network_offset(skb));
187 esph = ip_esp_hdr(skb);
188 *skb_mac_header(skb) = IPPROTO_ESP;
189
190 esph->spi = x->id.spi;
191 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output);
192
193 sg_init_table(sg, nfrags);
194 skb_to_sgvec(skb, sg,
195 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
196 clen + alen);
197 sg_init_one(asg, esph, sizeof(*esph));
198
199 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
200 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
201 aead_givcrypt_set_assoc(req, asg, sizeof(*esph));
202 aead_givcrypt_set_giv(req, esph->enc_data,
203 XFRM_SKB_CB(skb)->seq.output);
204
205 ESP_SKB_CB(skb)->tmp = tmp;
206 err = crypto_aead_givencrypt(req);
207 if (err == -EINPROGRESS)
208 goto error;
209
210 if (err == -EBUSY)
211 err = NET_XMIT_DROP;
212
213 kfree(tmp);
214
215 error:
216 return err;
217 }
218
219 static int esp_input_done2(struct sk_buff *skb, int err)
220 {
221 struct xfrm_state *x = xfrm_input_state(skb);
222 struct esp_data *esp = x->data;
223 struct crypto_aead *aead = esp->aead;
224 int alen = crypto_aead_authsize(aead);
225 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
226 int elen = skb->len - hlen;
227 int hdr_len = skb_network_header_len(skb);
228 int padlen;
229 u8 nexthdr[2];
230
231 kfree(ESP_SKB_CB(skb)->tmp);
232
233 if (unlikely(err))
234 goto out;
235
236 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
237 BUG();
238
239 err = -EINVAL;
240 padlen = nexthdr[0];
241 if (padlen + 2 + alen >= elen) {
242 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
243 "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
244 goto out;
245 }
246
247 /* ... check padding bits here. Silly. :-) */
248
249 pskb_trim(skb, skb->len - alen - padlen - 2);
250 __skb_pull(skb, hlen);
251 skb_set_transport_header(skb, -hdr_len);
252
253 err = nexthdr[1];
254
255 /* RFC4303: Drop dummy packets without any error */
256 if (err == IPPROTO_NONE)
257 err = -EINVAL;
258
259 out:
260 return err;
261 }
262
263 static void esp_input_done(struct crypto_async_request *base, int err)
264 {
265 struct sk_buff *skb = base->data;
266
267 xfrm_input_resume(skb, esp_input_done2(skb, err));
268 }
269
270 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
271 {
272 struct ip_esp_hdr *esph;
273 struct esp_data *esp = x->data;
274 struct crypto_aead *aead = esp->aead;
275 struct aead_request *req;
276 struct sk_buff *trailer;
277 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
278 int nfrags;
279 int ret = 0;
280 void *tmp;
281 u8 *iv;
282 struct scatterlist *sg;
283 struct scatterlist *asg;
284
285 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
286 ret = -EINVAL;
287 goto out;
288 }
289
290 if (elen <= 0) {
291 ret = -EINVAL;
292 goto out;
293 }
294
295 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
296 ret = -EINVAL;
297 goto out;
298 }
299
300 ret = -ENOMEM;
301 tmp = esp_alloc_tmp(aead, nfrags + 1);
302 if (!tmp)
303 goto out;
304
305 ESP_SKB_CB(skb)->tmp = tmp;
306 iv = esp_tmp_iv(aead, tmp);
307 req = esp_tmp_req(aead, iv);
308 asg = esp_req_sg(aead, req);
309 sg = asg + 1;
310
311 skb->ip_summed = CHECKSUM_NONE;
312
313 esph = (struct ip_esp_hdr *)skb->data;
314
315 /* Get ivec. This can be wrong, check against another impls. */
316 iv = esph->enc_data;
317
318 sg_init_table(sg, nfrags);
319 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
320 sg_init_one(asg, esph, sizeof(*esph));
321
322 aead_request_set_callback(req, 0, esp_input_done, skb);
323 aead_request_set_crypt(req, sg, sg, elen, iv);
324 aead_request_set_assoc(req, asg, sizeof(*esph));
325
326 ret = crypto_aead_decrypt(req);
327 if (ret == -EINPROGRESS)
328 goto out;
329
330 ret = esp_input_done2(skb, ret);
331
332 out:
333 return ret;
334 }
335
336 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
337 {
338 struct esp_data *esp = x->data;
339 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
340 u32 align = max_t(u32, blksize, esp->padlen);
341 u32 rem;
342
343 mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
344 rem = mtu & (align - 1);
345 mtu &= ~(align - 1);
346
347 if (x->props.mode != XFRM_MODE_TUNNEL) {
348 u32 padsize = ((blksize - 1) & 7) + 1;
349 mtu -= blksize - padsize;
350 mtu += min_t(u32, blksize - padsize, rem);
351 }
352
353 return mtu - 2;
354 }
355
356 static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
357 u8 type, u8 code, int offset, __be32 info)
358 {
359 struct net *net = dev_net(skb->dev);
360 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
361 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
362 struct xfrm_state *x;
363
364 if (type != ICMPV6_DEST_UNREACH &&
365 type != ICMPV6_PKT_TOOBIG)
366 return;
367
368 x = xfrm_state_lookup(net, (xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
369 if (!x)
370 return;
371 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%pI6\n",
372 ntohl(esph->spi), &iph->daddr);
373 xfrm_state_put(x);
374 }
375
376 static void esp6_destroy(struct xfrm_state *x)
377 {
378 struct esp_data *esp = x->data;
379
380 if (!esp)
381 return;
382
383 crypto_free_aead(esp->aead);
384 kfree(esp);
385 }
386
387 static int esp_init_aead(struct xfrm_state *x)
388 {
389 struct esp_data *esp = x->data;
390 struct crypto_aead *aead;
391 int err;
392
393 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
394 err = PTR_ERR(aead);
395 if (IS_ERR(aead))
396 goto error;
397
398 esp->aead = aead;
399
400 err = crypto_aead_setkey(aead, x->aead->alg_key,
401 (x->aead->alg_key_len + 7) / 8);
402 if (err)
403 goto error;
404
405 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
406 if (err)
407 goto error;
408
409 error:
410 return err;
411 }
412
413 static int esp_init_authenc(struct xfrm_state *x)
414 {
415 struct esp_data *esp = x->data;
416 struct crypto_aead *aead;
417 struct crypto_authenc_key_param *param;
418 struct rtattr *rta;
419 char *key;
420 char *p;
421 char authenc_name[CRYPTO_MAX_ALG_NAME];
422 unsigned int keylen;
423 int err;
424
425 err = -EINVAL;
426 if (x->ealg == NULL)
427 goto error;
428
429 err = -ENAMETOOLONG;
430 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)",
431 x->aalg ? x->aalg->alg_name : "digest_null",
432 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
433 goto error;
434
435 aead = crypto_alloc_aead(authenc_name, 0, 0);
436 err = PTR_ERR(aead);
437 if (IS_ERR(aead))
438 goto error;
439
440 esp->aead = aead;
441
442 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
443 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
444 err = -ENOMEM;
445 key = kmalloc(keylen, GFP_KERNEL);
446 if (!key)
447 goto error;
448
449 p = key;
450 rta = (void *)p;
451 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
452 rta->rta_len = RTA_LENGTH(sizeof(*param));
453 param = RTA_DATA(rta);
454 p += RTA_SPACE(sizeof(*param));
455
456 if (x->aalg) {
457 struct xfrm_algo_desc *aalg_desc;
458
459 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
460 p += (x->aalg->alg_key_len + 7) / 8;
461
462 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
463 BUG_ON(!aalg_desc);
464
465 err = -EINVAL;
466 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
467 crypto_aead_authsize(aead)) {
468 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
469 x->aalg->alg_name,
470 crypto_aead_authsize(aead),
471 aalg_desc->uinfo.auth.icv_fullbits/8);
472 goto free_key;
473 }
474
475 err = crypto_aead_setauthsize(
476 aead, aalg_desc->uinfo.auth.icv_truncbits / 8);
477 if (err)
478 goto free_key;
479 }
480
481 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
482 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
483
484 err = crypto_aead_setkey(aead, key, keylen);
485
486 free_key:
487 kfree(key);
488
489 error:
490 return err;
491 }
492
493 static int esp6_init_state(struct xfrm_state *x)
494 {
495 struct esp_data *esp;
496 struct crypto_aead *aead;
497 u32 align;
498 int err;
499
500 if (x->encap)
501 return -EINVAL;
502
503 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
504 if (esp == NULL)
505 return -ENOMEM;
506
507 x->data = esp;
508
509 if (x->aead)
510 err = esp_init_aead(x);
511 else
512 err = esp_init_authenc(x);
513
514 if (err)
515 goto error;
516
517 aead = esp->aead;
518
519 esp->padlen = 0;
520
521 x->props.header_len = sizeof(struct ip_esp_hdr) +
522 crypto_aead_ivsize(aead);
523 switch (x->props.mode) {
524 case XFRM_MODE_BEET:
525 if (x->sel.family != AF_INET6)
526 x->props.header_len += IPV4_BEET_PHMAXLEN +
527 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
528 break;
529 case XFRM_MODE_TRANSPORT:
530 break;
531 case XFRM_MODE_TUNNEL:
532 x->props.header_len += sizeof(struct ipv6hdr);
533 break;
534 default:
535 goto error;
536 }
537
538 align = ALIGN(crypto_aead_blocksize(aead), 4);
539 if (esp->padlen)
540 align = max_t(u32, align, esp->padlen);
541 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
542
543 error:
544 return err;
545 }
546
547 static const struct xfrm_type esp6_type =
548 {
549 .description = "ESP6",
550 .owner = THIS_MODULE,
551 .proto = IPPROTO_ESP,
552 .flags = XFRM_TYPE_REPLAY_PROT,
553 .init_state = esp6_init_state,
554 .destructor = esp6_destroy,
555 .get_mtu = esp6_get_mtu,
556 .input = esp6_input,
557 .output = esp6_output,
558 .hdr_offset = xfrm6_find_1stfragopt,
559 };
560
561 static const struct inet6_protocol esp6_protocol = {
562 .handler = xfrm6_rcv,
563 .err_handler = esp6_err,
564 .flags = INET6_PROTO_NOPOLICY,
565 };
566
567 static int __init esp6_init(void)
568 {
569 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
570 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
571 return -EAGAIN;
572 }
573 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
574 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
575 xfrm_unregister_type(&esp6_type, AF_INET6);
576 return -EAGAIN;
577 }
578
579 return 0;
580 }
581
582 static void __exit esp6_fini(void)
583 {
584 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
585 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
586 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
587 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
588 }
589
590 module_init(esp6_init);
591 module_exit(esp6_fini);
592
593 MODULE_LICENSE("GPL");
594 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
Linux with added FPC-III support