[IPv4] ESP: Discard dummy packets introduced in rfc4303

[IPv4] ESP: Discard dummy packets introduced in rfc4303

[Thomas Graf]

RFC4303 introduces dummy packets with a nexthdr value of 59
to implement traffic confidentiality. Such packets need to
be dropped silently and the payload may not be attempted to
be parsed as it consists of random chunk.

Signed-off-by: Thomas Graf <tgraf@suug.ch>

Index: net-2.6.25/net/ipv4/esp4.c
===================================================================
--- net-2.6.25.orig/net/ipv4/esp4.c	2007-12-10 15:57:23.000000000 +0100
+++ net-2.6.25/net/ipv4/esp4.c	2007-12-10 16:06:10.000000000 +0100
@@ -9,6 +9,7 @@
 #include <linux/pfkeyv2.h>
 #include <linux/random.h>
 #include <linux/spinlock.h>
+#include <linux/in6.h>
 #include <net/icmp.h>
 #include <net/protocol.h>
 #include <net/udp.h>
@@ -233,6 +234,10 @@
 
 	/* ... check padding bits here. Silly. :-) */
 
+	/* RFC4303: Drop dummy packets without any error */
+	if (nexthdr[1] == IPPROTO_NONE)
+		goto out;
+
 	iph = ip_hdr(skb);
 	ihl = iph->ihl * 4;
 

Re: [IPv4] ESP: Discard dummy packets introduced in rfc4303

[David Miller]

From: Thomas Graf <tgraf@suug.ch>
Date: Mon, 10 Dec 2007 23:17:03 +0100

> RFC4303 introduces dummy packets with a nexthdr value of 59
> to implement traffic confidentiality. Such packets need to
> be dropped silently and the payload may not be attempted to
> be parsed as it consists of random chunk.
> 
> Signed-off-by: Thomas Graf <tgraf@suug.ch>

Applied to net-2.6, since this is more of a bug fix than
anything else.