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linux/net/ipv4/esp4_offload.c
Ilan Tayari 8f92e03ecc esp4/6: Fix GSO path for non-GSO SW-crypto packets
If esp*_offload module is loaded, outbound packets take the
GSO code path, being encapsulated at layer 3, but encrypted
in layer 2. validate_xmit_xfrm calls esp*_xmit for that.

esp*_xmit was wrongfully detecting these packets as going
through hardware crypto offload, while in fact they should
be encrypted in software, causing plaintext leakage to
the network, and also dropping at the receiver side.

Perform the encryption in esp*_xmit, if the SA doesn't have
a hardware offload_handle.

Also, align esp6 code to esp4 logic.

Fixes: fca11ebde3 ("esp4: Reorganize esp_output")
Fixes: 383d0350f2 ("esp6: Reorganize esp_output")
Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2017-04-19 07:48:57 +02:00

306 lines
6.6 KiB
C

/*
* IPV4 GSO/GRO offload support
* Linux INET implementation
*
* Copyright (C) 2016 secunet Security Networks AG
* Author: Steffen Klassert <steffen.klassert@secunet.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* ESP GRO support
*/
#include <linux/skbuff.h>
#include <linux/init.h>
#include <net/protocol.h>
#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/slab.h>
#include <linux/spinlock.h>
#include <net/udp.h>
static struct sk_buff **esp4_gro_receive(struct sk_buff **head,
struct sk_buff *skb)
{
int offset = skb_gro_offset(skb);
struct xfrm_offload *xo;
struct xfrm_state *x;
__be32 seq;
__be32 spi;
int err;
skb_pull(skb, offset);
if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
goto out;
xo = xfrm_offload(skb);
if (!xo || !(xo->flags & CRYPTO_DONE)) {
err = secpath_set(skb);
if (err)
goto out;
if (skb->sp->len == XFRM_MAX_DEPTH)
goto out;
x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
(xfrm_address_t *)&ip_hdr(skb)->daddr,
spi, IPPROTO_ESP, AF_INET);
if (!x)
goto out;
skb->sp->xvec[skb->sp->len++] = x;
skb->sp->olen++;
xo = xfrm_offload(skb);
if (!xo) {
xfrm_state_put(x);
goto out;
}
}
xo->flags |= XFRM_GRO;
XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
XFRM_SPI_SKB_CB(skb)->family = AF_INET;
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
XFRM_SPI_SKB_CB(skb)->seq = seq;
/* We don't need to handle errors from xfrm_input, it does all
* the error handling and frees the resources on error. */
xfrm_input(skb, IPPROTO_ESP, spi, -2);
return ERR_PTR(-EINPROGRESS);
out:
skb_push(skb, offset);
NAPI_GRO_CB(skb)->same_flow = 0;
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
}
static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
{
struct ip_esp_hdr *esph;
struct iphdr *iph = ip_hdr(skb);
struct xfrm_offload *xo = xfrm_offload(skb);
int proto = iph->protocol;
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);
xo->proto = proto;
}
static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
netdev_features_t features)
{
__u32 seq;
int err = 0;
struct sk_buff *skb2;
struct xfrm_state *x;
struct ip_esp_hdr *esph;
struct crypto_aead *aead;
struct sk_buff *segs = ERR_PTR(-EINVAL);
netdev_features_t esp_features = features;
struct xfrm_offload *xo = xfrm_offload(skb);
if (!xo)
goto out;
seq = xo->seq.low;
x = skb->sp->xvec[skb->sp->len - 1];
aead = x->data;
esph = ip_esp_hdr(skb);
if (esph->spi != x->id.spi)
goto out;
if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
goto out;
__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
skb->encap_hdr_csum = 1;
if (!(features & NETIF_F_HW_ESP))
esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
segs = x->outer_mode->gso_segment(x, skb, esp_features);
if (IS_ERR_OR_NULL(segs))
goto out;
__skb_pull(skb, skb->data - skb_mac_header(skb));
skb2 = segs;
do {
struct sk_buff *nskb = skb2->next;
xo = xfrm_offload(skb2);
xo->flags |= XFRM_GSO_SEGMENT;
xo->seq.low = seq;
xo->seq.hi = xfrm_replay_seqhi(x, seq);
if(!(features & NETIF_F_HW_ESP))
xo->flags |= CRYPTO_FALLBACK;
x->outer_mode->xmit(x, skb2);
err = x->type_offload->xmit(x, skb2, esp_features);
if (err) {
kfree_skb_list(segs);
return ERR_PTR(err);
}
if (!skb_is_gso(skb2))
seq++;
else
seq += skb_shinfo(skb2)->gso_segs;
skb_push(skb2, skb2->mac_len);
skb2 = nskb;
} while (skb2);
out:
return segs;
}
static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
{
struct crypto_aead *aead = x->data;
if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
return -EINVAL;
skb->ip_summed = CHECKSUM_NONE;
return esp_input_done2(skb, 0);
}
static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
{
int err;
int alen;
int blksize;
struct xfrm_offload *xo;
struct ip_esp_hdr *esph;
struct crypto_aead *aead;
struct esp_info esp;
bool hw_offload = true;
esp.inplace = true;
xo = xfrm_offload(skb);
if (!xo)
return -EINVAL;
if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle ||
(x->xso.dev != skb->dev)) {
xo->flags |= CRYPTO_FALLBACK;
hw_offload = false;
}
esp.proto = xo->proto;
/* skb is pure payload to encrypt */
aead = x->data;
alen = crypto_aead_authsize(aead);
esp.tfclen = 0;
/* XXX: Add support for tfc padding here. */
blksize = ALIGN(crypto_aead_blocksize(aead), 4);
esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
esp.plen = esp.clen - skb->len - esp.tfclen;
esp.tailen = esp.tfclen + esp.plen + alen;
esp.esph = ip_esp_hdr(skb);
if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
esp.nfrags = esp_output_head(x, skb, &esp);
if (esp.nfrags < 0)
return esp.nfrags;
}
esph = esp.esph;
esph->spi = x->id.spi;
skb_push(skb, -skb_network_offset(skb));
if (xo->flags & XFRM_GSO_SEGMENT) {
esph->seq_no = htonl(xo->seq.low);
} else {
ip_hdr(skb)->tot_len = htons(skb->len);
ip_send_check(ip_hdr(skb));
}
if (hw_offload)
return 0;
esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
err = esp_output_tail(x, skb, &esp);
if (err < 0)
return err;
secpath_reset(skb);
return 0;
}
static const struct net_offload esp4_offload = {
.callbacks = {
.gro_receive = esp4_gro_receive,
.gso_segment = esp4_gso_segment,
},
};
static const struct xfrm_type_offload esp_type_offload = {
.description = "ESP4 OFFLOAD",
.owner = THIS_MODULE,
.proto = IPPROTO_ESP,
.input_tail = esp_input_tail,
.xmit = esp_xmit,
.encap = esp4_gso_encap,
};
static int __init esp4_offload_init(void)
{
if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
pr_info("%s: can't add xfrm type offload\n", __func__);
return -EAGAIN;
}
return inet_add_offload(&esp4_offload, IPPROTO_ESP);
}
static void __exit esp4_offload_exit(void)
{
if (xfrm_unregister_type_offload(&esp_type_offload, AF_INET) < 0)
pr_info("%s: can't remove xfrm type offload\n", __func__);
inet_del_offload(&esp4_offload, IPPROTO_ESP);
}
module_init(esp4_offload_init);
module_exit(esp4_offload_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");