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OpenCloudOS-Kernel/net/ipv6/esp6.c

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/*
* Copyright (C)2002 USAGI/WIDE Project
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors
*
* Mitsuru KANDA @USAGI : IPv6 Support
* Kazunori MIYAZAWA @USAGI :
* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
*
* This file is derived from net/ipv4/esp.c
*/
#include <linux/err.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/esp.h>
#include <asm/scatterlist.h>
#include <linux/crypto.h>
#include <linux/kernel.h>
#include <linux/pfkeyv2.h>
#include <linux/random.h>
#include <net/icmp.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <linux/icmpv6.h>
static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
int hdr_len;
struct ipv6hdr *top_iph;
struct ipv6_esp_hdr *esph;
struct crypto_blkcipher *tfm;
struct blkcipher_desc desc;
struct esp_data *esp;
struct sk_buff *trailer;
int blksize;
int clen;
int alen;
int nfrags;
esp = x->data;
hdr_len = skb->h.raw - skb->data +
sizeof(*esph) + esp->conf.ivlen;
/* Strip IP+ESP header. */
__skb_pull(skb, hdr_len);
/* Now skb is pure payload to encrypt */
err = -ENOMEM;
/* Round to block size */
clen = skb->len;
alen = esp->auth.icv_trunc_len;
tfm = esp->conf.tfm;
desc.tfm = tfm;
desc.flags = 0;
blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
clen = ALIGN(clen + 2, blksize);
if (esp->conf.padlen)
clen = ALIGN(clen, esp->conf.padlen);
if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
goto error;
}
/* Fill padding... */
do {
int i;
for (i=0; i<clen-skb->len - 2; i++)
*(u8*)(trailer->tail + i) = i+1;
} while (0);
*(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
pskb_put(skb, trailer, clen - skb->len);
top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len);
esph = (struct ipv6_esp_hdr *)skb->h.raw;
top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph));
*(u8*)(trailer->tail - 1) = *skb->nh.raw;
*skb->nh.raw = IPPROTO_ESP;
esph->spi = x->id.spi;
esph->seq_no = htonl(++x->replay.oseq);
xfrm_aevent_doreplay(x);
if (esp->conf.ivlen)
crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
do {
struct scatterlist *sg = &esp->sgbuf[0];
if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
if (!sg)
goto error;
}
skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);
} while (0);
if (unlikely(err))
goto error;
if (esp->conf.ivlen) {
memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
}
if (esp->auth.icv_full_len) {
err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
sizeof(*esph) + esp->conf.ivlen + clen);
memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
}
error:
return err;
}
static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph;
struct ipv6_esp_hdr *esph;
struct esp_data *esp = x->data;
struct crypto_blkcipher *tfm = esp->conf.tfm;
struct blkcipher_desc desc = { .tfm = tfm };
struct sk_buff *trailer;
int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
int alen = esp->auth.icv_trunc_len;
int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
int hdr_len = skb->h.raw - skb->nh.raw;
int nfrags;
int ret = 0;
if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) {
ret = -EINVAL;
goto out;
}
if (elen <= 0 || (elen & (blksize-1))) {
ret = -EINVAL;
goto out;
}
/* If integrity check is required, do this. */
if (esp->auth.icv_full_len) {
u8 sum[alen];
ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
if (ret)
goto out;
if (skb_copy_bits(skb, skb->len - alen, sum, alen))
BUG();
if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
x->stats.integrity_failed++;
ret = -EINVAL;
goto out;
}
}
if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
ret = -EINVAL;
goto out;
}
skb->ip_summed = CHECKSUM_NONE;
esph = (struct ipv6_esp_hdr*)skb->data;
iph = skb->nh.ipv6h;
/* Get ivec. This can be wrong, check against another impls. */
if (esp->conf.ivlen)
crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
{
u8 nexthdr[2];
struct scatterlist *sg = &esp->sgbuf[0];
u8 padlen;
if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
if (!sg) {
ret = -ENOMEM;
goto out;
}
}
skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen);
ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);
if (unlikely(ret))
goto out;
if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
BUG();
padlen = nexthdr[0];
if (padlen+2 >= elen) {
LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
ret = -EINVAL;
goto out;
}
/* ... check padding bits here. Silly. :-) */
pskb_trim(skb, skb->len - alen - padlen - 2);
ret = nexthdr[1];
}
skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len;
out:
return ret;
}
static u32 esp6_get_max_size(struct xfrm_state *x, int mtu)
{
struct esp_data *esp = x->data;
u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
if (x->props.mode) {
mtu = ALIGN(mtu + 2, blksize);
} else {
/* The worst case. */
u32 padsize = ((blksize - 1) & 7) + 1;
mtu = ALIGN(mtu + 2, padsize) + blksize - padsize;
}
if (esp->conf.padlen)
mtu = ALIGN(mtu, esp->conf.padlen);
return mtu + x->props.header_len + esp->auth.icv_trunc_len;
}
static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
int type, int code, int offset, __u32 info)
{
struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset);
struct xfrm_state *x;
if (type != ICMPV6_DEST_UNREACH &&
type != ICMPV6_PKT_TOOBIG)
return;
x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
if (!x)
return;
printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
ntohl(esph->spi), NIP6(iph->daddr));
xfrm_state_put(x);
}
static void esp6_destroy(struct xfrm_state *x)
{
struct esp_data *esp = x->data;
if (!esp)
return;
crypto_free_blkcipher(esp->conf.tfm);
esp->conf.tfm = NULL;
kfree(esp->conf.ivec);
esp->conf.ivec = NULL;
crypto_free_hash(esp->auth.tfm);
esp->auth.tfm = NULL;
kfree(esp->auth.work_icv);
esp->auth.work_icv = NULL;
kfree(esp);
}
static int esp6_init_state(struct xfrm_state *x)
{
struct esp_data *esp = NULL;
struct crypto_blkcipher *tfm;
/* null auth and encryption can have zero length keys */
if (x->aalg) {
if (x->aalg->alg_key_len > 512)
goto error;
}
if (x->ealg == NULL)
goto error;
if (x->encap)
goto error;
esp = kzalloc(sizeof(*esp), GFP_KERNEL);
if (esp == NULL)
return -ENOMEM;
if (x->aalg) {
struct xfrm_algo_desc *aalg_desc;
struct crypto_hash *hash;
esp->auth.key = x->aalg->alg_key;
esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
hash = crypto_alloc_hash(x->aalg->alg_name, 0,
CRYPTO_ALG_ASYNC);
if (IS_ERR(hash))
goto error;
esp->auth.tfm = hash;
if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len))
goto error;
aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
BUG_ON(!aalg_desc);
if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
crypto_hash_digestsize(hash)) {
NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
x->aalg->alg_name,
crypto_hash_digestsize(hash),
aalg_desc->uinfo.auth.icv_fullbits/8);
goto error;
}
esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
if (!esp->auth.work_icv)
goto error;
}
esp->conf.key = x->ealg->alg_key;
esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm))
goto error;
esp->conf.tfm = tfm;
esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
esp->conf.padlen = 0;
if (esp->conf.ivlen) {
esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
if (unlikely(esp->conf.ivec == NULL))
goto error;
get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
}
if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len))
goto error;
x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen;
if (x->props.mode)
x->props.header_len += sizeof(struct ipv6hdr);
x->data = esp;
return 0;
error:
x->data = esp;
esp6_destroy(x);
x->data = NULL;
return -EINVAL;
}
static struct xfrm_type esp6_type =
{
.description = "ESP6",
.owner = THIS_MODULE,
.proto = IPPROTO_ESP,
.init_state = esp6_init_state,
.destructor = esp6_destroy,
.get_max_size = esp6_get_max_size,
.input = esp6_input,
.output = esp6_output
};
static struct inet6_protocol esp6_protocol = {
.handler = xfrm6_rcv,
.err_handler = esp6_err,
.flags = INET6_PROTO_NOPOLICY,
};
static int __init esp6_init(void)
{
if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
return -EAGAIN;
}
if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
xfrm_unregister_type(&esp6_type, AF_INET6);
return -EAGAIN;
}
return 0;
}
static void __exit esp6_fini(void)
{
if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
}
module_init(esp6_init);
module_exit(esp6_fini);
MODULE_LICENSE("GPL");
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