- 根目录:
- net
- ipv6
- esp6.c
/*
* 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 <crypto/aead.h>
#include <crypto/authenc.h>
#include <linux/err.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/esp.h>
#include <linux/scatterlist.h>
#include <linux/kernel.h>
#include <linux/pfkeyv2.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <net/icmp.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <linux/icmpv6.h>
struct esp_skb_cb {
struct xfrm_skb_cb xfrm;
void *tmp;
};
#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
/*
* Allocate an AEAD request structure with extra space for SG and IV.
*
* For alignment considerations the upper 32 bits of the sequence number are
* placed at the front, if present. Followed by the IV, the request and finally
* the SG list.
*
* TODO: Use spare space in skb for this where possible.
*/
static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
{
unsigned int len;
len = seqihlen;
len += crypto_aead_ivsize(aead);
if (len) {
len += crypto_aead_alignmask(aead) &
~(crypto_tfm_ctx_alignment() - 1);
len = ALIGN(len, crypto_tfm_ctx_alignment());
}
len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
len = ALIGN(len, __alignof__(struct scatterlist));
len += sizeof(struct scatterlist) * nfrags;
return kmalloc(len, GFP_ATOMIC);
}
static inline __be32 *esp_tmp_seqhi(void *tmp)
{
return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
}
static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
{
return crypto_aead_ivsize(aead) ?
PTR_ALIGN((u8 *)tmp + seqhilen,
crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
}
static inline struct aead_givcrypt_request *esp_tmp_givreq(
struct crypto_aead *aead, u8 *iv)
{
struct aead_givcrypt_request *req;
req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
crypto_tfm_ctx_alignment());
aead_givcrypt_set_tfm(req, aead);
return req;
}
static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
{
struct aead_request *req;
req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
crypto_tfm_ctx_alignment());
aead_request_set_tfm(req, aead);
return req;
}
static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
struct aead_request *req)
{
return (void *)ALIGN((unsigned long)(req + 1) +
crypto_aead_reqsize(aead),
__alignof__(struct scatterlist));
}
static inline struct scatterlist *esp_givreq_sg(
struct crypto_aead *aead, struct aead_givcrypt_request *req)
{
return (void *)ALIGN((unsigned long)(req + 1) +
crypto_aead_reqsize(aead),
__alignof__(struct scatterlist));
}
static void esp_output_done(struct crypto_async_request *base, int err)
{
struct sk_buff *skb = base->data;
kfree(ESP_SKB_CB(skb)->tmp);
xfrm_output_resume(skb, err);
}
static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
struct ip_esp_hdr *esph;
struct crypto_aead *aead;
struct aead_givcrypt_request *req;
struct scatterlist *sg;
struct scatterlist *asg;
struct sk_buff *trailer;
void *tmp;
int blksize;
int clen;
int alen;
int plen;
int tfclen;
int nfrags;
int assoclen;
int sglists;
int seqhilen;
u8 *iv;
u8 *tail;
__be32 *seqhi;
struct esp_data *esp = x->data;
/* skb is pure payload to encrypt */
err = -ENOMEM;
aead = esp->aead;
alen = crypto_aead_authsize(aead);
tfclen = 0;
if (x->tfcpad) {
struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
u32 padto;
padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
if (skb->len < padto)
tfclen = padto - skb->len;
}
blksize = ALIGN(crypto_aead_blocksize(aead), 4);
clen = ALIGN(skb->len + 2 + tfclen, blksize);
if (esp->padlen)
clen = ALIGN(clen, esp->padlen);
plen = clen - skb->len - tfclen;
err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
if (err < 0)
goto error;
nfrags = err;
assoclen = sizeof(*esph);
sglists = 1;
seqhilen = 0;
if (x->props.flags & XFRM_STATE_ESN) {
sglists += 2;
seqhilen += sizeof(__be32);
assoclen += seqhilen;
}
tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
if (!tmp)
goto error;
seqhi = esp_tmp_seqhi(tmp);
iv = esp_tmp_iv(aead, tmp, seqhilen);
req = esp_tmp_givreq(aead, iv);
asg = esp_givreq_sg(aead, req);
sg = asg + sglists;
/* Fill padding... */
tail = skb_tail_pointer(trailer);
if (tfclen) {
memset(tail, 0, tfclen);
tail += tfclen;
}
do {
int i;
for (i = 0; i < plen - 2; i++)
tail[i] = i + 1;
} while (0);
tail[plen - 2] = plen - 2;
tail[plen - 1] = *skb_mac_header(skb);
pskb_put(skb, trailer, clen - skb->len + alen);
skb_push(skb, -skb_network_offset(skb));
esph = ip_esp_hdr(skb);
*skb_mac_header(skb) = IPPROTO_ESP;
esph->spi = x->id.spi;
esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
sg_init_table(sg, nfrags);
skb_to_sgvec(skb, sg,
esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
clen + alen);
if ((x->props.flags & XFRM_STATE_ESN)) {
sg_init_table(asg, 3);
sg_set_buf(asg, &esph->spi, sizeof(__be32));
*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
sg_set_buf(asg + 1, seqhi, seqhilen);
sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
} else
sg_init_one(asg, esph, sizeof(*esph));
aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
aead_givcrypt_set_assoc(req, asg, assoclen);
aead_givcrypt_set_giv(req, esph->enc_data,
XFRM_SKB_CB(skb)->seq.output.low);
ESP_SKB_CB(skb)->tmp = tmp;
err = crypto_aead_givencrypt(req);
if (err == -EINPROGRESS)
goto error;
if (err == -EBUSY)
err = NET_XMIT_DROP;
kfree(tmp);
error:
return err;
}
static int esp_input_done2(struct sk_buff *skb, int err)
{
struct xfrm_state *x = xfrm_input_state(skb);
struct esp_data *esp = x->data;
struct crypto_aead *aead = esp->aead;
int alen = crypto_aead_authsize(aead);
int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
int elen = skb->len - hlen;
int hdr_len = skb_network_header_len(skb);
int padlen;
u8 nexthdr[2];
kfree(ESP_SKB_CB(skb)->tmp);
if (unlikely(err))
goto out;
if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
BUG();
err = -EINVAL;
padlen = nexthdr[0];
if (padlen + 2 + alen >= elen) {
LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
"padlen=%d, elen=%d\n", padlen + 2, elen - alen);
goto out;
}
/* ... check padding bits here. Silly. :-) */
pskb_trim(skb, skb->len - alen - padlen - 2);
__skb_pull(skb, hlen);
skb_set_transport_header(skb, -hdr_len);
err = nexthdr[1];
/* RFC4303: Drop dummy packets without any error */
if (err == IPPROTO_NONE)
err = -EINVAL;
out:
return err;
}
static void esp_input_done(struct crypto_async_request *base, int err)
{
struct sk_buff *skb = base->data;
xfrm_input_resume(skb, esp_input_done2(skb, err));
}
static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct ip_esp_hdr *esph;
struct esp_data *esp = x->data;
struct crypto_aead *aead = esp->aead;
struct aead_request *req;
struct sk_buff *trailer;
int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
int nfrags;
int assoclen;
int sglists;
int seqhilen;
int ret = 0;
void *tmp;
__be32 *seqhi;
u8 *iv;
struct scatterlist *sg;
struct scatterlist *asg;
if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
ret = -EINVAL;
goto out;
}
if (elen <= 0) {
ret = -EINVAL;
goto out;
}
if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
ret = -EINVAL;
goto out;
}
ret = -ENOMEM;
assoclen = sizeof(*esph);
sglists = 1;
seqhilen = 0;
if (x->props.flags & XFRM_STATE_ESN) {
sglists += 2;
seqhilen += sizeof(__be32);
assoclen += seqhilen;
}
tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
if (!tmp)
goto out;
ESP_SKB_CB(skb)->tmp = tmp;
seqhi = esp_tmp_seqhi(tmp);
iv = esp_tmp_iv(aead, tmp, seqhilen);
req = esp_tmp_req(aead, iv);
asg = esp_req_sg(aead, req);
sg = asg + sglists;
skb->ip_summed = CHECKSUM_NONE;
esph = (struct ip_esp_hdr *)skb->data;
/* Get ivec. This can be wrong, check against another impls. */
iv = esph->enc_data;
sg_init_table(sg, nfrags);
skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
if ((x->props.flags & XFRM_STATE_ESN)) {
sg_init_table(asg, 3);
sg_set_buf(asg, &esph->spi, sizeof(__be32));
*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
sg_set_buf(asg + 1, seqhi, seqhilen);
sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
} else
sg_init_one(asg, esph, sizeof(*esph));
aead_request_set_callback(req, 0, esp_input_done, skb);
aead_request_set_crypt(req, sg, sg, elen, iv);
aead_request_set_assoc(req, asg, assoclen);
ret = crypto_aead_decrypt(req);
if (ret == -EINPROGRESS)
goto out;
ret = esp_input_done2(skb, ret);
out:
return ret;
}
static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
{
struct esp_data *esp = x->data;
u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
u32 align = max_t(u32, blksize, esp->padlen);
u32 rem;
mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
rem = mtu & (align - 1);
mtu &= ~(align - 1);
if (x->props.mode != XFRM_MODE_TUNNEL) {
u32 padsize = ((blksize - 1) & 7) + 1;
mtu -= blksize - padsize;
mtu += min_t(u32, blksize - padsize, rem);
}
return mtu - 2;
}
static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
struct net *net = dev_net(skb->dev);
const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
struct xfrm_state *x;
if (type != ICMPV6_DEST_UNREACH &&
type != ICMPV6_PKT_TOOBIG)
return;
x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
esph->spi, IPPROTO_ESP, AF_INET6);
if (!x)
return;
printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%pI6\n",
ntohl(esph->spi), &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_aead(esp->aead);
kfree(esp);
}
static int esp_init_aead(struct xfrm_state *x)
{
struct esp_data *esp = x->data;
struct crypto_aead *aead;
int err;
aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
err = PTR_ERR(aead);
if (IS_ERR(aead))
goto error;
esp->aead = aead;
err = crypto_aead_setkey(aead, x->aead->alg_key,
(x->aead->alg_key_len + 7) / 8);
if (err)
goto error;
err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
if (err)
goto error;
error:
return err;
}
static int esp_init_authenc(struct xfrm_state *x)
{
struct esp_data *esp = x->data;
struct crypto_aead *aead;
struct crypto_authenc_key_param *param;
struct rtattr *rta;
char *key;
char *p;
char authenc_name[CRYPTO_MAX_ALG_NAME];
unsigned int keylen;
int err;
err = -EINVAL;
if (x->ealg == NULL)
goto error;
err = -ENAMETOOLONG;
if ((x->props.flags & XFRM_STATE_ESN)) {
if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
"authencesn(%s,%s)",
x->aalg ? x->aalg->alg_name : "digest_null",
x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
goto error;
} else {
if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
"authenc(%s,%s)",
x->aalg ? x->aalg->alg_name : "digest_null",
x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
goto error;
}
aead = crypto_alloc_aead(authenc_name, 0, 0);
err = PTR_ERR(aead);
if (IS_ERR(aead))
goto error;
esp->aead = aead;
keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
(x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
err = -ENOMEM;
key = kmalloc(keylen, GFP_KERNEL);
if (!key)
goto error;
p = key;
rta = (void *)p;
rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
rta->rta_len = RTA_LENGTH(sizeof(*param));
param = RTA_DATA(rta);
p += RTA_SPACE(sizeof(*param));
if (x->aalg) {
struct xfrm_algo_desc *aalg_desc;
memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
p += (x->aalg->alg_key_len + 7) / 8;
aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
BUG_ON(!aalg_desc);
err = -EINVAL;
if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
crypto_aead_authsize(aead)) {
NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
x->aalg->alg_name,
crypto_aead_authsize(aead),
aalg_desc->uinfo.auth.icv_fullbits/8);
goto free_key;
}
err = crypto_aead_setauthsize(
aead, x->aalg->alg_trunc_len / 8);
if (err)
goto free_key;
}
param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
err = crypto_aead_setkey(aead, key, keylen);
free_key:
kfree(key);
error:
return err;
}
static int esp6_init_state(struct xfrm_state *x)
{
struct esp_data *esp;
struct crypto_aead *aead;
u32 align;
int err;
if (x->encap)
return -EINVAL;
esp = kzalloc(sizeof(*esp), GFP_KERNEL);
if (esp == NULL)
return -ENOMEM;
x->data = esp;
if (x->aead)
err = esp_init_aead(x);
else
err = esp_init_authenc(x);
if (err)
goto error;
aead = esp->aead;
esp->padlen = 0;
x->props.header_len = sizeof(struct ip_esp_hdr) +
crypto_aead_ivsize(aead);
switch (x->props.mode) {
case XFRM_MODE_BEET:
if (x->sel.family != AF_INET6)
x->props.header_len += IPV4_BEET_PHMAXLEN +
(sizeof(struct ipv6hdr) - sizeof(struct iphdr));
break;
case XFRM_MODE_TRANSPORT:
break;
case XFRM_MODE_TUNNEL:
x->props.header_len += sizeof(struct ipv6hdr);
break;
default:
goto error;
}
align = ALIGN(crypto_aead_blocksize(aead), 4);
if (esp->padlen)
align = max_t(u32, align, esp->padlen);
x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
error:
return err;
}
static const struct xfrm_type esp6_type =
{
.description = "ESP6",
.owner = THIS_MODULE,
.proto = IPPROTO_ESP,
.flags = XFRM_TYPE_REPLAY_PROT,
.init_state = esp6_init_state,
.destructor = esp6_destroy,
.get_mtu = esp6_get_mtu,
.input = esp6_input,
.output = esp6_output,
.hdr_offset = xfrm6_find_1stfragopt,
};
static const 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");
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);