blob: e78680a9985b2cf86a1b6671c1a73a258973a57c [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Herbert Xu6b7326c2006-07-30 15:41:01 +100027#include <linux/err.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/module.h>
29#include <net/ip.h>
30#include <net/xfrm.h>
31#include <net/esp.h>
32#include <asm/scatterlist.h>
33#include <linux/crypto.h>
Herbert Xua02a6422005-10-10 21:11:08 -070034#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#include <linux/pfkeyv2.h>
36#include <linux/random.h>
37#include <net/icmp.h>
38#include <net/ipv6.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020039#include <net/protocol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040#include <linux/icmpv6.h>
41
42static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
43{
44 int err;
45 int hdr_len;
46 struct ipv6hdr *top_iph;
47 struct ipv6_esp_hdr *esph;
Herbert Xu6b7326c2006-07-30 15:41:01 +100048 struct crypto_blkcipher *tfm;
49 struct blkcipher_desc desc;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 struct esp_data *esp;
51 struct sk_buff *trailer;
52 int blksize;
53 int clen;
54 int alen;
55 int nfrags;
56
57 esp = x->data;
58 hdr_len = skb->h.raw - skb->data +
59 sizeof(*esph) + esp->conf.ivlen;
60
61 /* Strip IP+ESP header. */
62 __skb_pull(skb, hdr_len);
63
64 /* Now skb is pure payload to encrypt */
65 err = -ENOMEM;
66
67 /* Round to block size */
68 clen = skb->len;
69
70 alen = esp->auth.icv_trunc_len;
71 tfm = esp->conf.tfm;
Herbert Xu6b7326c2006-07-30 15:41:01 +100072 desc.tfm = tfm;
73 desc.flags = 0;
74 blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
Herbert Xua02a6422005-10-10 21:11:08 -070075 clen = ALIGN(clen + 2, blksize);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 if (esp->conf.padlen)
Herbert Xua02a6422005-10-10 21:11:08 -070077 clen = ALIGN(clen, esp->conf.padlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79 if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
80 goto error;
81 }
82
83 /* Fill padding... */
84 do {
85 int i;
86 for (i=0; i<clen-skb->len - 2; i++)
87 *(u8*)(trailer->tail + i) = i+1;
88 } while (0);
89 *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
90 pskb_put(skb, trailer, clen - skb->len);
91
92 top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len);
93 esph = (struct ipv6_esp_hdr *)skb->h.raw;
94 top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
95 *(u8*)(trailer->tail - 1) = *skb->nh.raw;
96 *skb->nh.raw = IPPROTO_ESP;
97
98 esph->spi = x->id.spi;
99 esph->seq_no = htonl(++x->replay.oseq);
Jamal Hadi Salim9500e8a2006-03-20 19:15:29 -0800100 xfrm_aevent_doreplay(x);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
David S. Millere4bec822006-09-22 15:17:35 -0700102 if (esp->conf.ivlen) {
103 if (unlikely(!esp->conf.ivinitted)) {
104 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
105 esp->conf.ivinitted = 1;
106 }
Herbert Xu6b7326c2006-07-30 15:41:01 +1000107 crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
David S. Millere4bec822006-09-22 15:17:35 -0700108 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109
110 do {
111 struct scatterlist *sg = &esp->sgbuf[0];
112
113 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
114 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
115 if (!sg)
116 goto error;
117 }
118 skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
Herbert Xu6b7326c2006-07-30 15:41:01 +1000119 err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 if (unlikely(sg != &esp->sgbuf[0]))
121 kfree(sg);
122 } while (0);
123
Herbert Xu6b7326c2006-07-30 15:41:01 +1000124 if (unlikely(err))
125 goto error;
126
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 if (esp->conf.ivlen) {
Herbert Xu6b7326c2006-07-30 15:41:01 +1000128 memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
129 crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 }
131
132 if (esp->auth.icv_full_len) {
Herbert Xu07d4ee52006-08-20 14:24:50 +1000133 err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
134 sizeof(*esph) + esp->conf.ivlen + clen);
135 memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 }
137
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138error:
139 return err;
140}
141
Herbert Xue6956332006-04-01 00:52:46 -0800142static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143{
144 struct ipv6hdr *iph;
145 struct ipv6_esp_hdr *esph;
146 struct esp_data *esp = x->data;
Herbert Xu6b7326c2006-07-30 15:41:01 +1000147 struct crypto_blkcipher *tfm = esp->conf.tfm;
148 struct blkcipher_desc desc = { .tfm = tfm };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 struct sk_buff *trailer;
Herbert Xu6b7326c2006-07-30 15:41:01 +1000150 int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 int alen = esp->auth.icv_trunc_len;
152 int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
153
154 int hdr_len = skb->h.raw - skb->nh.raw;
155 int nfrags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 int ret = 0;
157
158 if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
159 ret = -EINVAL;
Herbert Xu31a4ab92006-05-27 23:06:13 -0700160 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 }
162
163 if (elen <= 0 || (elen & (blksize-1))) {
164 ret = -EINVAL;
Herbert Xu31a4ab92006-05-27 23:06:13 -0700165 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 }
167
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 /* If integrity check is required, do this. */
169 if (esp->auth.icv_full_len) {
Herbert Xu07d4ee52006-08-20 14:24:50 +1000170 u8 sum[alen];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
Herbert Xu07d4ee52006-08-20 14:24:50 +1000172 ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
173 if (ret)
174 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
Herbert Xu07d4ee52006-08-20 14:24:50 +1000176 if (skb_copy_bits(skb, skb->len - alen, sum, alen))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 BUG();
178
Herbert Xu07d4ee52006-08-20 14:24:50 +1000179 if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 x->stats.integrity_failed++;
181 ret = -EINVAL;
182 goto out;
183 }
184 }
185
186 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
187 ret = -EINVAL;
188 goto out;
189 }
190
191 skb->ip_summed = CHECKSUM_NONE;
192
193 esph = (struct ipv6_esp_hdr*)skb->data;
194 iph = skb->nh.ipv6h;
195
196 /* Get ivec. This can be wrong, check against another impls. */
197 if (esp->conf.ivlen)
Herbert Xu6b7326c2006-07-30 15:41:01 +1000198 crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
200 {
201 u8 nexthdr[2];
202 struct scatterlist *sg = &esp->sgbuf[0];
203 u8 padlen;
204
205 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
206 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
207 if (!sg) {
208 ret = -ENOMEM;
209 goto out;
210 }
211 }
212 skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
Herbert Xu6b7326c2006-07-30 15:41:01 +1000213 ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 if (unlikely(sg != &esp->sgbuf[0]))
215 kfree(sg);
Herbert Xu6b7326c2006-07-30 15:41:01 +1000216 if (unlikely(ret))
217 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
219 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
220 BUG();
221
222 padlen = nexthdr[0];
223 if (padlen+2 >= elen) {
Patrick McHardy64ce2072005-08-09 20:50:53 -0700224 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 ret = -EINVAL;
226 goto out;
227 }
228 /* ... check padding bits here. Silly. :-) */
229
230 pskb_trim(skb, skb->len - alen - padlen - 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 ret = nexthdr[1];
232 }
233
Herbert Xu31a4ab92006-05-27 23:06:13 -0700234 skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len;
235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 return ret;
238}
239
240static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
241{
242 struct esp_data *esp = x->data;
Herbert Xu6b7326c2006-07-30 15:41:01 +1000243 u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700245 if (x->props.mode == XFRM_MODE_TUNNEL) {
Herbert Xua02a6422005-10-10 21:11:08 -0700246 mtu = ALIGN(mtu + 2, blksize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 } else {
248 /* The worst case. */
Herbert Xud4875b02005-10-10 21:11:34 -0700249 u32 padsize = ((blksize - 1) & 7) + 1;
250 mtu = ALIGN(mtu + 2, padsize) + blksize - padsize;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 }
252 if (esp->conf.padlen)
Herbert Xua02a6422005-10-10 21:11:08 -0700253 mtu = ALIGN(mtu, esp->conf.padlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
Kazunori MIYAZAWA73d4f842005-12-08 23:11:42 -0800255 return mtu + x->props.header_len + esp->auth.icv_trunc_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256}
257
258static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
259 int type, int code, int offset, __u32 info)
260{
261 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
262 struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset);
263 struct xfrm_state *x;
264
265 if (type != ICMPV6_DEST_UNREACH &&
266 type != ICMPV6_PKT_TOOBIG)
267 return;
268
269 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
270 if (!x)
271 return;
Joe Perches46b86a22006-01-13 14:29:07 -0800272 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 ntohl(esph->spi), NIP6(iph->daddr));
274 xfrm_state_put(x);
275}
276
277static void esp6_destroy(struct xfrm_state *x)
278{
279 struct esp_data *esp = x->data;
280
281 if (!esp)
282 return;
283
Herbert Xu6b7326c2006-07-30 15:41:01 +1000284 crypto_free_blkcipher(esp->conf.tfm);
Jesper Juhl573dbd92005-09-01 17:44:29 -0700285 esp->conf.tfm = NULL;
286 kfree(esp->conf.ivec);
287 esp->conf.ivec = NULL;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000288 crypto_free_hash(esp->auth.tfm);
Jesper Juhl573dbd92005-09-01 17:44:29 -0700289 esp->auth.tfm = NULL;
290 kfree(esp->auth.work_icv);
291 esp->auth.work_icv = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 kfree(esp);
293}
294
Herbert Xu72cb6962005-06-20 13:18:08 -0700295static int esp6_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296{
297 struct esp_data *esp = NULL;
Herbert Xu6b7326c2006-07-30 15:41:01 +1000298 struct crypto_blkcipher *tfm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299
300 /* null auth and encryption can have zero length keys */
301 if (x->aalg) {
302 if (x->aalg->alg_key_len > 512)
303 goto error;
304 }
305 if (x->ealg == NULL)
306 goto error;
307
308 if (x->encap)
309 goto error;
310
Ingo Oeser0c600ed2006-03-20 23:01:32 -0800311 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 if (esp == NULL)
313 return -ENOMEM;
314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 if (x->aalg) {
316 struct xfrm_algo_desc *aalg_desc;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000317 struct crypto_hash *hash;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318
319 esp->auth.key = x->aalg->alg_key;
320 esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000321 hash = crypto_alloc_hash(x->aalg->alg_name, 0,
322 CRYPTO_ALG_ASYNC);
323 if (IS_ERR(hash))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 goto error;
Herbert Xu07d4ee52006-08-20 14:24:50 +1000325
326 esp->auth.tfm = hash;
327 if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
328 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
330 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
331 BUG_ON(!aalg_desc);
332
333 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
Herbert Xu07d4ee52006-08-20 14:24:50 +1000334 crypto_hash_digestsize(hash)) {
335 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
336 x->aalg->alg_name,
337 crypto_hash_digestsize(hash),
338 aalg_desc->uinfo.auth.icv_fullbits/8);
339 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 }
341
342 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
343 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
344
345 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
346 if (!esp->auth.work_icv)
347 goto error;
348 }
349 esp->conf.key = x->ealg->alg_key;
350 esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
Herbert Xu6b7326c2006-07-30 15:41:01 +1000351 tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
352 if (IS_ERR(tfm))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 goto error;
Herbert Xu6b7326c2006-07-30 15:41:01 +1000354 esp->conf.tfm = tfm;
355 esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 esp->conf.padlen = 0;
357 if (esp->conf.ivlen) {
358 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
359 if (unlikely(esp->conf.ivec == NULL))
360 goto error;
David S. Millere4bec822006-09-22 15:17:35 -0700361 esp->conf.ivinitted = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 }
Herbert Xu6b7326c2006-07-30 15:41:01 +1000363 if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 goto error;
365 x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
Masahide NAKAMURA7e49e6d2006-09-22 15:05:15 -0700366 if (x->props.mode == XFRM_MODE_TUNNEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 x->props.header_len += sizeof(struct ipv6hdr);
368 x->data = esp;
369 return 0;
370
371error:
372 x->data = esp;
373 esp6_destroy(x);
374 x->data = NULL;
375 return -EINVAL;
376}
377
378static struct xfrm_type esp6_type =
379{
380 .description = "ESP6",
381 .owner = THIS_MODULE,
382 .proto = IPPROTO_ESP,
383 .init_state = esp6_init_state,
384 .destructor = esp6_destroy,
385 .get_max_size = esp6_get_max_size,
386 .input = esp6_input,
Masahide NAKAMURAaee5adb2006-08-23 17:57:28 -0700387 .output = esp6_output,
388 .hdr_offset = xfrm6_find_1stfragopt,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389};
390
391static struct inet6_protocol esp6_protocol = {
392 .handler = xfrm6_rcv,
393 .err_handler = esp6_err,
394 .flags = INET6_PROTO_NOPOLICY,
395};
396
397static int __init esp6_init(void)
398{
399 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
400 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
401 return -EAGAIN;
402 }
403 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
404 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
405 xfrm_unregister_type(&esp6_type, AF_INET6);
406 return -EAGAIN;
407 }
408
409 return 0;
410}
411
412static void __exit esp6_fini(void)
413{
414 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
415 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
416 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
417 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
418}
419
420module_init(esp6_init);
421module_exit(esp6_fini);
422
423MODULE_LICENSE("GPL");