2 * Copyright (C)2002 USAGI/WIDE Project
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.
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.
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
20 * Mitsuru KANDA @USAGI : IPv6 Support
21 * Kazunori MIYAZAWA @USAGI :
22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
24 * This file is derived from net/ipv4/esp.c
27 #include <linux/err.h>
28 #include <linux/module.h>
32 #include <asm/scatterlist.h>
33 #include <linux/crypto.h>
34 #include <linux/kernel.h>
35 #include <linux/pfkeyv2.h>
36 #include <linux/random.h>
39 #include <net/protocol.h>
40 #include <linux/icmpv6.h>
42 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
46 struct ipv6hdr *top_iph;
47 struct ipv6_esp_hdr *esph;
48 struct crypto_blkcipher *tfm;
49 struct blkcipher_desc desc;
51 struct sk_buff *trailer;
58 hdr_len = skb->h.raw - skb->data +
59 sizeof(*esph) + esp->conf.ivlen;
61 /* Strip IP+ESP header. */
62 __skb_pull(skb, hdr_len);
64 /* Now skb is pure payload to encrypt */
67 /* Round to block size */
70 alen = esp->auth.icv_trunc_len;
74 blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
75 clen = ALIGN(clen + 2, blksize);
77 clen = ALIGN(clen, esp->conf.padlen);
79 if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
86 for (i=0; i<clen-skb->len - 2; i++)
87 *(u8*)(trailer->tail + i) = i+1;
89 *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
90 pskb_put(skb, trailer, clen - skb->len);
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;
98 esph->spi = x->id.spi;
99 esph->seq_no = htonl(++x->replay.oseq);
100 xfrm_aevent_doreplay(x);
103 crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
106 struct scatterlist *sg = &esp->sgbuf[0];
108 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
109 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
113 skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
114 err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
115 if (unlikely(sg != &esp->sgbuf[0]))
122 if (esp->conf.ivlen) {
123 memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
124 crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
127 if (esp->auth.icv_full_len) {
128 err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
129 sizeof(*esph) + esp->conf.ivlen + clen);
130 memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
137 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
140 struct ipv6_esp_hdr *esph;
141 struct esp_data *esp = x->data;
142 struct crypto_blkcipher *tfm = esp->conf.tfm;
143 struct blkcipher_desc desc = { .tfm = tfm };
144 struct sk_buff *trailer;
145 int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
146 int alen = esp->auth.icv_trunc_len;
147 int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
149 int hdr_len = skb->h.raw - skb->nh.raw;
153 if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
158 if (elen <= 0 || (elen & (blksize-1))) {
163 /* If integrity check is required, do this. */
164 if (esp->auth.icv_full_len) {
167 ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
171 if (skb_copy_bits(skb, skb->len - alen, sum, alen))
174 if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
175 x->stats.integrity_failed++;
181 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
186 skb->ip_summed = CHECKSUM_NONE;
188 esph = (struct ipv6_esp_hdr*)skb->data;
191 /* Get ivec. This can be wrong, check against another impls. */
193 crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
197 struct scatterlist *sg = &esp->sgbuf[0];
200 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
201 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
207 skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
208 ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
209 if (unlikely(sg != &esp->sgbuf[0]))
214 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
218 if (padlen+2 >= elen) {
219 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
223 /* ... check padding bits here. Silly. :-) */
225 pskb_trim(skb, skb->len - alen - padlen - 2);
229 skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len;
235 static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
237 struct esp_data *esp = x->data;
238 u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
241 mtu = ALIGN(mtu + 2, blksize);
243 /* The worst case. */
244 u32 padsize = ((blksize - 1) & 7) + 1;
245 mtu = ALIGN(mtu + 2, padsize) + blksize - padsize;
247 if (esp->conf.padlen)
248 mtu = ALIGN(mtu, esp->conf.padlen);
250 return mtu + x->props.header_len + esp->auth.icv_trunc_len;
253 static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
254 int type, int code, int offset, __u32 info)
256 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
257 struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset);
258 struct xfrm_state *x;
260 if (type != ICMPV6_DEST_UNREACH &&
261 type != ICMPV6_PKT_TOOBIG)
264 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
267 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
268 ntohl(esph->spi), NIP6(iph->daddr));
272 static void esp6_destroy(struct xfrm_state *x)
274 struct esp_data *esp = x->data;
279 crypto_free_blkcipher(esp->conf.tfm);
280 esp->conf.tfm = NULL;
281 kfree(esp->conf.ivec);
282 esp->conf.ivec = NULL;
283 crypto_free_hash(esp->auth.tfm);
284 esp->auth.tfm = NULL;
285 kfree(esp->auth.work_icv);
286 esp->auth.work_icv = NULL;
290 static int esp6_init_state(struct xfrm_state *x)
292 struct esp_data *esp = NULL;
293 struct crypto_blkcipher *tfm;
295 /* null auth and encryption can have zero length keys */
297 if (x->aalg->alg_key_len > 512)
306 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
311 struct xfrm_algo_desc *aalg_desc;
312 struct crypto_hash *hash;
314 esp->auth.key = x->aalg->alg_key;
315 esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
316 hash = crypto_alloc_hash(x->aalg->alg_name, 0,
321 esp->auth.tfm = hash;
322 if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
325 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
328 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
329 crypto_hash_digestsize(hash)) {
330 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
332 crypto_hash_digestsize(hash),
333 aalg_desc->uinfo.auth.icv_fullbits/8);
337 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
338 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
340 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
341 if (!esp->auth.work_icv)
344 esp->conf.key = x->ealg->alg_key;
345 esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
346 tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
350 esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
351 esp->conf.padlen = 0;
352 if (esp->conf.ivlen) {
353 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
354 if (unlikely(esp->conf.ivec == NULL))
356 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
358 if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
360 x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
362 x->props.header_len += sizeof(struct ipv6hdr);
373 static struct xfrm_type esp6_type =
375 .description = "ESP6",
376 .owner = THIS_MODULE,
377 .proto = IPPROTO_ESP,
378 .init_state = esp6_init_state,
379 .destructor = esp6_destroy,
380 .get_max_size = esp6_get_max_size,
382 .output = esp6_output
385 static struct inet6_protocol esp6_protocol = {
386 .handler = xfrm6_rcv,
387 .err_handler = esp6_err,
388 .flags = INET6_PROTO_NOPOLICY,
391 static int __init esp6_init(void)
393 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
394 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
397 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
398 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
399 xfrm_unregister_type(&esp6_type, AF_INET6);
406 static void __exit esp6_fini(void)
408 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
409 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
410 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
411 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
414 module_init(esp6_init);
415 module_exit(esp6_fini);
417 MODULE_LICENSE("GPL");