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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>
34#include <linux/pfkeyv2.h>
35#include <linux/random.h>
36#include <net/icmp.h>
37#include <net/ipv6.h>
38#include <linux/icmpv6.h>
39
40static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
41{
42 int err;
43 int hdr_len;
44 struct ipv6hdr *top_iph;
45 struct ipv6_esp_hdr *esph;
46 struct crypto_tfm *tfm;
47 struct esp_data *esp;
48 struct sk_buff *trailer;
49 int blksize;
50 int clen;
51 int alen;
52 int nfrags;
53
54 esp = x->data;
55 hdr_len = skb->h.raw - skb->data +
56 sizeof(*esph) + esp->conf.ivlen;
57
58 /* Strip IP+ESP header. */
59 __skb_pull(skb, hdr_len);
60
61 /* Now skb is pure payload to encrypt */
62 err = -ENOMEM;
63
64 /* Round to block size */
65 clen = skb->len;
66
67 alen = esp->auth.icv_trunc_len;
68 tfm = esp->conf.tfm;
69 blksize = (crypto_tfm_alg_blocksize(tfm) + 3) & ~3;
70 clen = (clen + 2 + blksize-1)&~(blksize-1);
71 if (esp->conf.padlen)
72 clen = (clen + esp->conf.padlen-1)&~(esp->conf.padlen-1);
73
74 if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
75 goto error;
76 }
77
78 /* Fill padding... */
79 do {
80 int i;
81 for (i=0; i<clen-skb->len - 2; i++)
82 *(u8*)(trailer->tail + i) = i+1;
83 } while (0);
84 *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
85 pskb_put(skb, trailer, clen - skb->len);
86
87 top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len);
88 esph = (struct ipv6_esp_hdr *)skb->h.raw;
89 top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
90 *(u8*)(trailer->tail - 1) = *skb->nh.raw;
91 *skb->nh.raw = IPPROTO_ESP;
92
93 esph->spi = x->id.spi;
94 esph->seq_no = htonl(++x->replay.oseq);
95
96 if (esp->conf.ivlen)
97 crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
98
99 do {
100 struct scatterlist *sg = &esp->sgbuf[0];
101
102 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
103 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
104 if (!sg)
105 goto error;
106 }
107 skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
108 crypto_cipher_encrypt(tfm, sg, sg, clen);
109 if (unlikely(sg != &esp->sgbuf[0]))
110 kfree(sg);
111 } while (0);
112
113 if (esp->conf.ivlen) {
114 memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
115 crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
116 }
117
118 if (esp->auth.icv_full_len) {
119 esp->auth.icv(esp, skb, (u8*)esph-skb->data,
120 sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen+clen, trailer->tail);
121 pskb_put(skb, trailer, alen);
122 }
123
124 err = 0;
125
126error:
127 return err;
128}
129
130static int esp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
131{
132 struct ipv6hdr *iph;
133 struct ipv6_esp_hdr *esph;
134 struct esp_data *esp = x->data;
135 struct sk_buff *trailer;
136 int blksize = crypto_tfm_alg_blocksize(esp->conf.tfm);
137 int alen = esp->auth.icv_trunc_len;
138 int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
139
140 int hdr_len = skb->h.raw - skb->nh.raw;
141 int nfrags;
142 unsigned char *tmp_hdr = NULL;
143 int ret = 0;
144
145 if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
146 ret = -EINVAL;
147 goto out_nofree;
148 }
149
150 if (elen <= 0 || (elen & (blksize-1))) {
151 ret = -EINVAL;
152 goto out_nofree;
153 }
154
155 tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
156 if (!tmp_hdr) {
157 ret = -ENOMEM;
158 goto out_nofree;
159 }
160 memcpy(tmp_hdr, skb->nh.raw, hdr_len);
161
162 /* If integrity check is required, do this. */
163 if (esp->auth.icv_full_len) {
164 u8 sum[esp->auth.icv_full_len];
165 u8 sum1[alen];
166
167 esp->auth.icv(esp, skb, 0, skb->len-alen, sum);
168
169 if (skb_copy_bits(skb, skb->len-alen, sum1, alen))
170 BUG();
171
172 if (unlikely(memcmp(sum, sum1, alen))) {
173 x->stats.integrity_failed++;
174 ret = -EINVAL;
175 goto out;
176 }
177 }
178
179 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
180 ret = -EINVAL;
181 goto out;
182 }
183
184 skb->ip_summed = CHECKSUM_NONE;
185
186 esph = (struct ipv6_esp_hdr*)skb->data;
187 iph = skb->nh.ipv6h;
188
189 /* Get ivec. This can be wrong, check against another impls. */
190 if (esp->conf.ivlen)
191 crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm));
192
193 {
194 u8 nexthdr[2];
195 struct scatterlist *sg = &esp->sgbuf[0];
196 u8 padlen;
197
198 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
199 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
200 if (!sg) {
201 ret = -ENOMEM;
202 goto out;
203 }
204 }
205 skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
206 crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen);
207 if (unlikely(sg != &esp->sgbuf[0]))
208 kfree(sg);
209
210 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
211 BUG();
212
213 padlen = nexthdr[0];
214 if (padlen+2 >= elen) {
Patrick McHardy64ce2072005-08-09 20:50:53 -0700215 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 ret = -EINVAL;
217 goto out;
218 }
219 /* ... check padding bits here. Silly. :-) */
220
221 pskb_trim(skb, skb->len - alen - padlen - 2);
222 skb->h.raw = skb_pull(skb, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen);
223 skb->nh.raw += sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
224 memcpy(skb->nh.raw, tmp_hdr, hdr_len);
225 skb->nh.ipv6h->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
226 ret = nexthdr[1];
227 }
228
229out:
230 kfree(tmp_hdr);
231out_nofree:
232 return ret;
233}
234
235static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
236{
237 struct esp_data *esp = x->data;
238 u32 blksize = crypto_tfm_alg_blocksize(esp->conf.tfm);
239
240 if (x->props.mode) {
241 mtu = (mtu + 2 + blksize-1)&~(blksize-1);
242 } else {
243 /* The worst case. */
244 mtu += 2 + blksize;
245 }
246 if (esp->conf.padlen)
247 mtu = (mtu + esp->conf.padlen-1)&~(esp->conf.padlen-1);
248
249 return mtu + x->props.header_len + esp->auth.icv_full_len;
250}
251
252static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
253 int type, int code, int offset, __u32 info)
254{
255 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
256 struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset);
257 struct xfrm_state *x;
258
259 if (type != ICMPV6_DEST_UNREACH &&
260 type != ICMPV6_PKT_TOOBIG)
261 return;
262
263 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
264 if (!x)
265 return;
266 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/"
267 "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
268 ntohl(esph->spi), NIP6(iph->daddr));
269 xfrm_state_put(x);
270}
271
272static void esp6_destroy(struct xfrm_state *x)
273{
274 struct esp_data *esp = x->data;
275
276 if (!esp)
277 return;
278
Jesper Juhl573dbd92005-09-01 17:44:29 -0700279 crypto_free_tfm(esp->conf.tfm);
280 esp->conf.tfm = NULL;
281 kfree(esp->conf.ivec);
282 esp->conf.ivec = NULL;
283 crypto_free_tfm(esp->auth.tfm);
284 esp->auth.tfm = NULL;
285 kfree(esp->auth.work_icv);
286 esp->auth.work_icv = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 kfree(esp);
288}
289
Herbert Xu72cb6962005-06-20 13:18:08 -0700290static int esp6_init_state(struct xfrm_state *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291{
292 struct esp_data *esp = NULL;
293
294 /* null auth and encryption can have zero length keys */
295 if (x->aalg) {
296 if (x->aalg->alg_key_len > 512)
297 goto error;
298 }
299 if (x->ealg == NULL)
300 goto error;
301
302 if (x->encap)
303 goto error;
304
305 esp = kmalloc(sizeof(*esp), GFP_KERNEL);
306 if (esp == NULL)
307 return -ENOMEM;
308
309 memset(esp, 0, sizeof(*esp));
310
311 if (x->aalg) {
312 struct xfrm_algo_desc *aalg_desc;
313
314 esp->auth.key = x->aalg->alg_key;
315 esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
316 esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
317 if (esp->auth.tfm == NULL)
318 goto error;
319 esp->auth.icv = esp_hmac_digest;
320
321 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
322 BUG_ON(!aalg_desc);
323
324 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
325 crypto_tfm_alg_digestsize(esp->auth.tfm)) {
326 printk(KERN_INFO "ESP: %s digestsize %u != %hu\n",
327 x->aalg->alg_name,
328 crypto_tfm_alg_digestsize(esp->auth.tfm),
329 aalg_desc->uinfo.auth.icv_fullbits/8);
330 goto error;
331 }
332
333 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
334 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
335
336 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
337 if (!esp->auth.work_icv)
338 goto error;
339 }
340 esp->conf.key = x->ealg->alg_key;
341 esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
342 if (x->props.ealgo == SADB_EALG_NULL)
343 esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB);
344 else
345 esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC);
346 if (esp->conf.tfm == NULL)
347 goto error;
348 esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.tfm);
349 esp->conf.padlen = 0;
350 if (esp->conf.ivlen) {
351 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
352 if (unlikely(esp->conf.ivec == NULL))
353 goto error;
354 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
355 }
356 if (crypto_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len))
357 goto error;
358 x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
359 if (x->props.mode)
360 x->props.header_len += sizeof(struct ipv6hdr);
361 x->data = esp;
362 return 0;
363
364error:
365 x->data = esp;
366 esp6_destroy(x);
367 x->data = NULL;
368 return -EINVAL;
369}
370
371static struct xfrm_type esp6_type =
372{
373 .description = "ESP6",
374 .owner = THIS_MODULE,
375 .proto = IPPROTO_ESP,
376 .init_state = esp6_init_state,
377 .destructor = esp6_destroy,
378 .get_max_size = esp6_get_max_size,
379 .input = esp6_input,
380 .output = esp6_output
381};
382
383static struct inet6_protocol esp6_protocol = {
384 .handler = xfrm6_rcv,
385 .err_handler = esp6_err,
386 .flags = INET6_PROTO_NOPOLICY,
387};
388
389static int __init esp6_init(void)
390{
391 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
392 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
393 return -EAGAIN;
394 }
395 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
396 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
397 xfrm_unregister_type(&esp6_type, AF_INET6);
398 return -EAGAIN;
399 }
400
401 return 0;
402}
403
404static void __exit esp6_fini(void)
405{
406 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
407 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
408 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
409 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
410}
411
412module_init(esp6_init);
413module_exit(esp6_fini);
414
415MODULE_LICENSE("GPL");