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OpenCloudOS-Kernel/net/ipv4/esp4.c

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#include <linux/config.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/udp.h>
/* decapsulation data for use when post-processing */
struct esp_decap_data {
xfrm_address_t saddr;
__u16 sport;
__u8 proto;
};
static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
struct iphdr *top_iph;
struct ip_esp_hdr *esph;
struct crypto_tfm *tfm;
struct esp_data *esp;
struct sk_buff *trailer;
int blksize;
int clen;
int alen;
int nfrags;
/* Strip IP+ESP header. */
__skb_pull(skb, skb->h.raw - skb->data);
/* Now skb is pure payload to encrypt */
err = -ENOMEM;
/* Round to block size */
clen = skb->len;
esp = x->data;
alen = esp->auth.icv_trunc_len;
tfm = esp->conf.tfm;
blksize = ALIGN(crypto_tfm_alg_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);
__skb_push(skb, skb->data - skb->nh.raw);
top_iph = skb->nh.iph;
esph = (struct ip_esp_hdr *)(skb->nh.raw + top_iph->ihl*4);
top_iph->tot_len = htons(skb->len + alen);
*(u8*)(trailer->tail - 1) = top_iph->protocol;
/* this is non-NULL only with UDP Encapsulation */
if (x->encap) {
struct xfrm_encap_tmpl *encap = x->encap;
struct udphdr *uh;
u32 *udpdata32;
uh = (struct udphdr *)esph;
uh->source = encap->encap_sport;
uh->dest = encap->encap_dport;
uh->len = htons(skb->len + alen - top_iph->ihl*4);
uh->check = 0;
switch (encap->encap_type) {
default:
case UDP_ENCAP_ESPINUDP:
esph = (struct ip_esp_hdr *)(uh + 1);
break;
case UDP_ENCAP_ESPINUDP_NON_IKE:
udpdata32 = (u32 *)(uh + 1);
udpdata32[0] = udpdata32[1] = 0;
esph = (struct ip_esp_hdr *)(udpdata32 + 2);
break;
}
top_iph->protocol = IPPROTO_UDP;
} else
top_iph->protocol = IPPROTO_ESP;
esph->spi = x->id.spi;
esph->seq_no = htonl(++x->replay.oseq);
if (esp->conf.ivlen)
crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
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);
crypto_cipher_encrypt(tfm, sg, sg, clen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);
} while (0);
if (esp->conf.ivlen) {
memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
}
if (esp->auth.icv_full_len) {
esp->auth.icv(esp, skb, (u8*)esph-skb->data,
sizeof(struct ip_esp_hdr) + esp->conf.ivlen+clen, trailer->tail);
pskb_put(skb, trailer, alen);
}
ip_send_check(top_iph);
err = 0;
error:
return err;
}
/*
* Note: detecting truncated vs. non-truncated authentication data is very
* expensive, so we only support truncated data, which is the recommended
* and common case.
*/
static int esp_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
{
struct iphdr *iph;
struct ip_esp_hdr *esph;
struct esp_data *esp = x->data;
struct sk_buff *trailer;
int blksize = ALIGN(crypto_tfm_alg_blocksize(esp->conf.tfm), 4);
int alen = esp->auth.icv_trunc_len;
int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen;
int nfrags;
int encap_len = 0;
if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
goto out;
if (elen <= 0 || (elen & (blksize-1)))
goto out;
/* If integrity check is required, do this. */
if (esp->auth.icv_full_len) {
u8 sum[esp->auth.icv_full_len];
u8 sum1[alen];
esp->auth.icv(esp, skb, 0, skb->len-alen, sum);
if (skb_copy_bits(skb, skb->len-alen, sum1, alen))
BUG();
if (unlikely(memcmp(sum, sum1, alen))) {
x->stats.integrity_failed++;
goto out;
}
}
if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
goto out;
skb->ip_summed = CHECKSUM_NONE;
esph = (struct ip_esp_hdr*)skb->data;
iph = skb->nh.iph;
/* Get ivec. This can be wrong, check against another impls. */
if (esp->conf.ivlen)
crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm));
{
u8 nexthdr[2];
struct scatterlist *sg = &esp->sgbuf[0];
u8 workbuf[60];
int padlen;
if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
if (!sg)
goto out;
}
skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen);
crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen);
if (unlikely(sg != &esp->sgbuf[0]))
kfree(sg);
if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
BUG();
padlen = nexthdr[0];
if (padlen+2 >= elen)
goto out;
/* ... check padding bits here. Silly. :-) */
if (x->encap && decap && decap->decap_type) {
struct esp_decap_data *encap_data;
struct udphdr *uh = (struct udphdr *) (iph+1);
encap_data = (struct esp_decap_data *) (decap->decap_data);
encap_data->proto = 0;
switch (decap->decap_type) {
case UDP_ENCAP_ESPINUDP:
case UDP_ENCAP_ESPINUDP_NON_IKE:
encap_data->proto = AF_INET;
encap_data->saddr.a4 = iph->saddr;
encap_data->sport = uh->source;
encap_len = (void*)esph - (void*)uh;
break;
default:
goto out;
}
}
iph->protocol = nexthdr[1];
pskb_trim(skb, skb->len - alen - padlen - 2);
memcpy(workbuf, skb->nh.raw, iph->ihl*4);
skb->h.raw = skb_pull(skb, sizeof(struct ip_esp_hdr) + esp->conf.ivlen);
skb->nh.raw += encap_len + sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
memcpy(skb->nh.raw, workbuf, iph->ihl*4);
skb->nh.iph->tot_len = htons(skb->len);
}
return 0;
out:
return -EINVAL;
}
static int esp_post_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
{
if (x->encap) {
struct xfrm_encap_tmpl *encap;
struct esp_decap_data *decap_data;
encap = x->encap;
decap_data = (struct esp_decap_data *)(decap->decap_data);
/* first, make sure that the decap type == the encap type */
if (encap->encap_type != decap->decap_type)
return -EINVAL;
switch (encap->encap_type) {
default:
case UDP_ENCAP_ESPINUDP:
case UDP_ENCAP_ESPINUDP_NON_IKE:
/*
* 1) if the NAT-T peer's IP or port changed then
* advertize the change to the keying daemon.
* This is an inbound SA, so just compare
* SRC ports.
*/
if (decap_data->proto == AF_INET &&
(decap_data->saddr.a4 != x->props.saddr.a4 ||
decap_data->sport != encap->encap_sport)) {
xfrm_address_t ipaddr;
ipaddr.a4 = decap_data->saddr.a4;
km_new_mapping(x, &ipaddr, decap_data->sport);
/* XXX: perhaps add an extra
* policy check here, to see
* if we should allow or
* reject a packet from a
* different source
* address/port.
*/
}
/*
* 2) ignore UDP/TCP checksums in case
* of NAT-T in Transport Mode, or
* perform other post-processing fixes
* as per * draft-ietf-ipsec-udp-encaps-06,
* section 3.1.2
*/
if (!x->props.mode)
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
}
return 0;
}
static u32 esp4_get_max_size(struct xfrm_state *x, int mtu)
{
struct esp_data *esp = x->data;
u32 blksize = ALIGN(crypto_tfm_alg_blocksize(esp->conf.tfm), 4);
if (x->props.mode) {
mtu = ALIGN(mtu + 2, blksize);
} else {
/* The worst case. */
mtu = ALIGN(mtu + 2, 4) + blksize - 4;
}
if (esp->conf.padlen)
mtu = ALIGN(mtu, esp->conf.padlen);
return mtu + x->props.header_len + esp->auth.icv_trunc_len;
}
static void esp4_err(struct sk_buff *skb, u32 info)
{
struct iphdr *iph = (struct iphdr*)skb->data;
struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
struct xfrm_state *x;
if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
skb->h.icmph->code != ICMP_FRAG_NEEDED)
return;
x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
if (!x)
return;
NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
ntohl(esph->spi), ntohl(iph->daddr));
xfrm_state_put(x);
}
static void esp_destroy(struct xfrm_state *x)
{
struct esp_data *esp = x->data;
if (!esp)
return;
crypto_free_tfm(esp->conf.tfm);
esp->conf.tfm = NULL;
kfree(esp->conf.ivec);
esp->conf.ivec = NULL;
crypto_free_tfm(esp->auth.tfm);
esp->auth.tfm = NULL;
kfree(esp->auth.work_icv);
esp->auth.work_icv = NULL;
kfree(esp);
}
static int esp_init_state(struct xfrm_state *x)
{
struct esp_data *esp = NULL;
/* 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;
esp = kmalloc(sizeof(*esp), GFP_KERNEL);
if (esp == NULL)
return -ENOMEM;
memset(esp, 0, sizeof(*esp));
if (x->aalg) {
struct xfrm_algo_desc *aalg_desc;
esp->auth.key = x->aalg->alg_key;
esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
if (esp->auth.tfm == NULL)
goto error;
esp->auth.icv = esp_hmac_digest;
aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
BUG_ON(!aalg_desc);
if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
crypto_tfm_alg_digestsize(esp->auth.tfm)) {
NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
x->aalg->alg_name,
crypto_tfm_alg_digestsize(esp->auth.tfm),
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;
if (x->props.ealgo == SADB_EALG_NULL)
esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB);
else
esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC);
if (esp->conf.tfm == NULL)
goto error;
esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.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_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len))
goto error;
x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
if (x->props.mode)
x->props.header_len += sizeof(struct iphdr);
if (x->encap) {
struct xfrm_encap_tmpl *encap = x->encap;
switch (encap->encap_type) {
default:
goto error;
case UDP_ENCAP_ESPINUDP:
x->props.header_len += sizeof(struct udphdr);
break;
case UDP_ENCAP_ESPINUDP_NON_IKE:
x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
break;
}
}
x->data = esp;
x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len;
return 0;
error:
x->data = esp;
esp_destroy(x);
x->data = NULL;
return -EINVAL;
}
static struct xfrm_type esp_type =
{
.description = "ESP4",
.owner = THIS_MODULE,
.proto = IPPROTO_ESP,
.init_state = esp_init_state,
.destructor = esp_destroy,
.get_max_size = esp4_get_max_size,
.input = esp_input,
.post_input = esp_post_input,
.output = esp_output
};
static struct net_protocol esp4_protocol = {
.handler = xfrm4_rcv,
.err_handler = esp4_err,
.no_policy = 1,
};
static int __init esp4_init(void)
{
struct xfrm_decap_state decap;
if (sizeof(struct esp_decap_data) >
sizeof(decap.decap_data)) {
extern void decap_data_too_small(void);
decap_data_too_small();
}
if (xfrm_register_type(&esp_type, AF_INET) < 0) {
printk(KERN_INFO "ip esp init: can't add xfrm type\n");
return -EAGAIN;
}
if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
printk(KERN_INFO "ip esp init: can't add protocol\n");
xfrm_unregister_type(&esp_type, AF_INET);
return -EAGAIN;
}
return 0;
}
static void __exit esp4_fini(void)
{
if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
printk(KERN_INFO "ip esp close: can't remove protocol\n");
if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
}
module_init(esp4_init);
module_exit(esp4_fini);
MODULE_LICENSE("GPL");
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