blob: a15a6f320f7000c5b512ff3f6f3085a33016c3df [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
27#include <linux/config.h>
28#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;
48 struct crypto_tfm *tfm;
49 struct esp_data *esp;
50 struct sk_buff *trailer;
51 int blksize;
52 int clen;
53 int alen;
54 int nfrags;
55
56 esp = x->data;
57 hdr_len = skb->h.raw - skb->data +
58 sizeof(*esph) + esp->conf.ivlen;
59
60 /* Strip IP+ESP header. */
61 __skb_pull(skb, hdr_len);
62
63 /* Now skb is pure payload to encrypt */
64 err = -ENOMEM;
65
66 /* Round to block size */
67 clen = skb->len;
68
69 alen = esp->auth.icv_trunc_len;
70 tfm = esp->conf.tfm;
Herbert Xua02a6422005-10-10 21:11:08 -070071 blksize = ALIGN(crypto_tfm_alg_blocksize(tfm), 4);
72 clen = ALIGN(clen + 2, blksize);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 if (esp->conf.padlen)
Herbert Xua02a6422005-10-10 21:11:08 -070074 clen = ALIGN(clen, esp->conf.padlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
76 if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
77 goto error;
78 }
79
80 /* Fill padding... */
81 do {
82 int i;
83 for (i=0; i<clen-skb->len - 2; i++)
84 *(u8*)(trailer->tail + i) = i+1;
85 } while (0);
86 *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
87 pskb_put(skb, trailer, clen - skb->len);
88
89 top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len);
90 esph = (struct ipv6_esp_hdr *)skb->h.raw;
91 top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
92 *(u8*)(trailer->tail - 1) = *skb->nh.raw;
93 *skb->nh.raw = IPPROTO_ESP;
94
95 esph->spi = x->id.spi;
96 esph->seq_no = htonl(++x->replay.oseq);
Jamal Hadi Salim9500e8a2006-03-20 19:15:29 -080097 xfrm_aevent_doreplay(x);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
99 if (esp->conf.ivlen)
100 crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
101
102 do {
103 struct scatterlist *sg = &esp->sgbuf[0];
104
105 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
106 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
107 if (!sg)
108 goto error;
109 }
110 skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
111 crypto_cipher_encrypt(tfm, sg, sg, clen);
112 if (unlikely(sg != &esp->sgbuf[0]))
113 kfree(sg);
114 } while (0);
115
116 if (esp->conf.ivlen) {
117 memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
118 crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
119 }
120
121 if (esp->auth.icv_full_len) {
122 esp->auth.icv(esp, skb, (u8*)esph-skb->data,
123 sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen+clen, trailer->tail);
124 pskb_put(skb, trailer, alen);
125 }
126
127 err = 0;
128
129error:
130 return err;
131}
132
Herbert Xue6956332006-04-01 00:52:46 -0800133static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134{
135 struct ipv6hdr *iph;
136 struct ipv6_esp_hdr *esph;
137 struct esp_data *esp = x->data;
138 struct sk_buff *trailer;
Herbert Xud4875b02005-10-10 21:11:34 -0700139 int blksize = ALIGN(crypto_tfm_alg_blocksize(esp->conf.tfm), 4);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 int alen = esp->auth.icv_trunc_len;
141 int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
142
143 int hdr_len = skb->h.raw - skb->nh.raw;
144 int nfrags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 int ret = 0;
146
147 if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
148 ret = -EINVAL;
Herbert Xu31a4ab92006-05-27 23:06:13 -0700149 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 }
151
152 if (elen <= 0 || (elen & (blksize-1))) {
153 ret = -EINVAL;
Herbert Xu31a4ab92006-05-27 23:06:13 -0700154 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 }
156
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 /* If integrity check is required, do this. */
158 if (esp->auth.icv_full_len) {
159 u8 sum[esp->auth.icv_full_len];
160 u8 sum1[alen];
161
162 esp->auth.icv(esp, skb, 0, skb->len-alen, sum);
163
164 if (skb_copy_bits(skb, skb->len-alen, sum1, alen))
165 BUG();
166
167 if (unlikely(memcmp(sum, sum1, alen))) {
168 x->stats.integrity_failed++;
169 ret = -EINVAL;
170 goto out;
171 }
172 }
173
174 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
175 ret = -EINVAL;
176 goto out;
177 }
178
179 skb->ip_summed = CHECKSUM_NONE;
180
181 esph = (struct ipv6_esp_hdr*)skb->data;
182 iph = skb->nh.ipv6h;
183
184 /* Get ivec. This can be wrong, check against another impls. */
185 if (esp->conf.ivlen)
186 crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm));
187
188 {
189 u8 nexthdr[2];
190 struct scatterlist *sg = &esp->sgbuf[0];
191 u8 padlen;
192
193 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
194 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
195 if (!sg) {
196 ret = -ENOMEM;
197 goto out;
198 }
199 }
200 skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
201 crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen);
202 if (unlikely(sg != &esp->sgbuf[0]))
203 kfree(sg);
204
205 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
206 BUG();
207
208 padlen = nexthdr[0];
209 if (padlen+2 >= elen) {
Patrick McHardy64ce2072005-08-09 20:50:53 -0700210 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 ret = -EINVAL;
212 goto out;
213 }
214 /* ... check padding bits here. Silly. :-) */
215
216 pskb_trim(skb, skb->len - alen - padlen - 2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 ret = nexthdr[1];
218 }
219
Herbert Xu31a4ab92006-05-27 23:06:13 -0700220 skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len;
221
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 return ret;
224}
225
226static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
227{
228 struct esp_data *esp = x->data;
Herbert Xud4875b02005-10-10 21:11:34 -0700229 u32 blksize = ALIGN(crypto_tfm_alg_blocksize(esp->conf.tfm), 4);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
231 if (x->props.mode) {
Herbert Xua02a6422005-10-10 21:11:08 -0700232 mtu = ALIGN(mtu + 2, blksize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 } else {
234 /* The worst case. */
Herbert Xud4875b02005-10-10 21:11:34 -0700235 u32 padsize = ((blksize - 1) & 7) + 1;
236 mtu = ALIGN(mtu + 2, padsize) + blksize - padsize;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 }
238 if (esp->conf.padlen)
Herbert Xua02a6422005-10-10 21:11:08 -0700239 mtu = ALIGN(mtu, esp->conf.padlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240
Kazunori MIYAZAWA73d4f842005-12-08 23:11:42 -0800241 return mtu + x->props.header_len + esp->auth.icv_trunc_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242}
243
244static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
245 int type, int code, int offset, __u32 info)
246{
247 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
248 struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset);
249 struct xfrm_state *x;
250
251 if (type != ICMPV6_DEST_UNREACH &&
252 type != ICMPV6_PKT_TOOBIG)
253 return;
254
255 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
256 if (!x)
257 return;
Joe Perches46b86a22006-01-13 14:29:07 -0800258 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 ntohl(esph->spi), NIP6(iph->daddr));
260 xfrm_state_put(x);
261}
262
263static void esp6_destroy(struct xfrm_state *x)
264{
265 struct esp_data *esp = x->data;
266
267 if (!esp)
268 return;
269
Jesper Juhl573dbd92005-09-01 17:44:29 -0700270 crypto_free_tfm(esp->conf.tfm);
271 esp->conf.tfm = NULL;
272 kfree(esp->conf.ivec);
273 esp->conf.ivec = NULL;
274 crypto_free_tfm(esp->auth.tfm);
275 esp->auth.tfm = NULL;
276 kfree(esp->auth.work_icv);
277 esp->auth.work_icv = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 kfree(esp);
279}
280
Herbert Xu72cb6962005-06-20 13:18:08 -0700281static int esp6_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282{
283 struct esp_data *esp = NULL;
284
285 /* null auth and encryption can have zero length keys */
286 if (x->aalg) {
287 if (x->aalg->alg_key_len > 512)
288 goto error;
289 }
290 if (x->ealg == NULL)
291 goto error;
292
293 if (x->encap)
294 goto error;
295
Ingo Oeser0c600ed2006-03-20 23:01:32 -0800296 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 if (esp == NULL)
298 return -ENOMEM;
299
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 if (x->aalg) {
301 struct xfrm_algo_desc *aalg_desc;
302
303 esp->auth.key = x->aalg->alg_key;
304 esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
305 esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
306 if (esp->auth.tfm == NULL)
307 goto error;
308 esp->auth.icv = esp_hmac_digest;
309
310 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
311 BUG_ON(!aalg_desc);
312
313 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
314 crypto_tfm_alg_digestsize(esp->auth.tfm)) {
315 printk(KERN_INFO "ESP: %s digestsize %u != %hu\n",
316 x->aalg->alg_name,
317 crypto_tfm_alg_digestsize(esp->auth.tfm),
318 aalg_desc->uinfo.auth.icv_fullbits/8);
319 goto error;
320 }
321
322 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
323 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
324
325 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
326 if (!esp->auth.work_icv)
327 goto error;
328 }
329 esp->conf.key = x->ealg->alg_key;
330 esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
331 if (x->props.ealgo == SADB_EALG_NULL)
332 esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB);
333 else
334 esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC);
335 if (esp->conf.tfm == NULL)
336 goto error;
337 esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.tfm);
338 esp->conf.padlen = 0;
339 if (esp->conf.ivlen) {
340 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
341 if (unlikely(esp->conf.ivec == NULL))
342 goto error;
343 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
344 }
345 if (crypto_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len))
346 goto error;
347 x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
348 if (x->props.mode)
349 x->props.header_len += sizeof(struct ipv6hdr);
350 x->data = esp;
351 return 0;
352
353error:
354 x->data = esp;
355 esp6_destroy(x);
356 x->data = NULL;
357 return -EINVAL;
358}
359
360static struct xfrm_type esp6_type =
361{
362 .description = "ESP6",
363 .owner = THIS_MODULE,
364 .proto = IPPROTO_ESP,
365 .init_state = esp6_init_state,
366 .destructor = esp6_destroy,
367 .get_max_size = esp6_get_max_size,
368 .input = esp6_input,
369 .output = esp6_output
370};
371
372static struct inet6_protocol esp6_protocol = {
373 .handler = xfrm6_rcv,
374 .err_handler = esp6_err,
375 .flags = INET6_PROTO_NOPOLICY,
376};
377
378static int __init esp6_init(void)
379{
380 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
381 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
382 return -EAGAIN;
383 }
384 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
385 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
386 xfrm_unregister_type(&esp6_type, AF_INET6);
387 return -EAGAIN;
388 }
389
390 return 0;
391}
392
393static void __exit esp6_fini(void)
394{
395 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
396 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
397 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
398 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
399}
400
401module_init(esp6_init);
402module_exit(esp6_fini);
403
404MODULE_LICENSE("GPL");