linux/net/ipv4/xfrm4_output.c
Steffen Klassert 044a832a77 xfrm: Fix local error reporting crash with interfamily tunnels
We set the outer mode protocol too early. As a result, the
local error handler might dispatch to the wrong address family
and report the error to a wrong socket type. We fix this by
setting the outer protocol to the skb after we accessed the
inner mode for the last time, right before we do the atcual
encapsulation where we switch finally to the outer mode.

Reported-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Tested-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2015-02-09 11:14:17 +01:00

112 lines
2.4 KiB
C

/*
* xfrm4_output.c - Common IPsec encapsulation code for IPv4.
* Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
*
* 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.
*/
#include <linux/if_ether.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter_ipv4.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>
static int xfrm4_tunnel_check_size(struct sk_buff *skb)
{
int mtu, ret = 0;
if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
goto out;
if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
goto out;
mtu = dst_mtu(skb_dst(skb));
if (skb->len > mtu) {
if (skb->sk)
xfrm_local_error(skb, mtu);
else
icmp_send(skb, ICMP_DEST_UNREACH,
ICMP_FRAG_NEEDED, htonl(mtu));
ret = -EMSGSIZE;
}
out:
return ret;
}
int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
err = xfrm4_tunnel_check_size(skb);
if (err)
return err;
XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
return xfrm4_extract_header(skb);
}
int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
err = xfrm_inner_extract_output(x, skb);
if (err)
return err;
IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
skb->protocol = htons(ETH_P_IP);
return x->outer_mode->output2(x, skb);
}
EXPORT_SYMBOL(xfrm4_prepare_output);
int xfrm4_output_finish(struct sk_buff *skb)
{
memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
#ifdef CONFIG_NETFILTER
IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
#endif
return xfrm_output(skb);
}
static int __xfrm4_output(struct sk_buff *skb)
{
struct xfrm_state *x = skb_dst(skb)->xfrm;
#ifdef CONFIG_NETFILTER
if (!x) {
IPCB(skb)->flags |= IPSKB_REROUTED;
return dst_output(skb);
}
#endif
return x->outer_mode->afinfo->output_finish(skb);
}
int xfrm4_output(struct sock *sk, struct sk_buff *skb)
{
return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
NULL, skb_dst(skb)->dev, __xfrm4_output,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
{
struct iphdr *hdr;
hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
inet_sk(skb->sk)->inet_dport, mtu);
}