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 esp->auth.icv(esp, skb, (u8*)esph-skb->data,
129 sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen+clen, trailer->tail);
130 pskb_put(skb, trailer, 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) {
165 u8 sum[esp->auth.icv_full_len];
168 esp->auth.icv(esp, skb, 0, skb->len-alen, sum);
170 if (skb_copy_bits(skb, skb->len-alen, sum1, alen))
173 if (unlikely(memcmp(sum, sum1, alen))) {
174 x->stats.integrity_failed++;
180 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
185 skb->ip_summed = CHECKSUM_NONE;
187 esph = (struct ipv6_esp_hdr*)skb->data;
190 /* Get ivec. This can be wrong, check against another impls. */
192 crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
196 struct scatterlist *sg = &esp->sgbuf[0];
199 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
200 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
206 skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
207 ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
208 if (unlikely(sg != &esp->sgbuf[0]))
213 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
217 if (padlen+2 >= elen) {
218 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
222 /* ... check padding bits here. Silly. :-) */
224 pskb_trim(skb, skb->len - alen - padlen - 2);
228 skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len;
234 static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
236 struct esp_data *esp = x->data;
237 u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
240 mtu = ALIGN(mtu + 2, blksize);
242 /* The worst case. */
243 u32 padsize = ((blksize - 1) & 7) + 1;
244 mtu = ALIGN(mtu + 2, padsize) + blksize - padsize;
246 if (esp->conf.padlen)
247 mtu = ALIGN(mtu, esp->conf.padlen);
249 return mtu + x->props.header_len + esp->auth.icv_trunc_len;
252 static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
253 int type, int code, int offset, __u32 info)
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;
259 if (type != ICMPV6_DEST_UNREACH &&
260 type != ICMPV6_PKT_TOOBIG)
263 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
266 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
267 ntohl(esph->spi), NIP6(iph->daddr));
271 static void esp6_destroy(struct xfrm_state *x)
273 struct esp_data *esp = x->data;
278 crypto_free_blkcipher(esp->conf.tfm);
279 esp->conf.tfm = NULL;
280 kfree(esp->conf.ivec);
281 esp->conf.ivec = NULL;
282 crypto_free_tfm(esp->auth.tfm);
283 esp->auth.tfm = NULL;
284 kfree(esp->auth.work_icv);
285 esp->auth.work_icv = NULL;
289 static int esp6_init_state(struct xfrm_state *x)
291 struct esp_data *esp = NULL;
292 struct crypto_blkcipher *tfm;
294 /* null auth and encryption can have zero length keys */
296 if (x->aalg->alg_key_len > 512)
305 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
310 struct xfrm_algo_desc *aalg_desc;
312 esp->auth.key = x->aalg->alg_key;
313 esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
314 esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
315 if (esp->auth.tfm == NULL)
317 esp->auth.icv = esp_hmac_digest;
319 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
322 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
323 crypto_tfm_alg_digestsize(esp->auth.tfm)) {
324 printk(KERN_INFO "ESP: %s digestsize %u != %hu\n",
326 crypto_tfm_alg_digestsize(esp->auth.tfm),
327 aalg_desc->uinfo.auth.icv_fullbits/8);
331 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
332 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
334 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
335 if (!esp->auth.work_icv)
338 esp->conf.key = x->ealg->alg_key;
339 esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
340 tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
344 esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
345 esp->conf.padlen = 0;
346 if (esp->conf.ivlen) {
347 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
348 if (unlikely(esp->conf.ivec == NULL))
350 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
352 if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
354 x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
356 x->props.header_len += sizeof(struct ipv6hdr);
367 static struct xfrm_type esp6_type =
369 .description = "ESP6",
370 .owner = THIS_MODULE,
371 .proto = IPPROTO_ESP,
372 .init_state = esp6_init_state,
373 .destructor = esp6_destroy,
374 .get_max_size = esp6_get_max_size,
376 .output = esp6_output
379 static struct inet6_protocol esp6_protocol = {
380 .handler = xfrm6_rcv,
381 .err_handler = esp6_err,
382 .flags = INET6_PROTO_NOPOLICY,
385 static int __init esp6_init(void)
387 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
388 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
391 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
392 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
393 xfrm_unregister_type(&esp6_type, AF_INET6);
400 static void __exit esp6_fini(void)
402 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
403 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
404 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
405 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
408 module_init(esp6_init);
409 module_exit(esp6_fini);
411 MODULE_LICENSE("GPL");