From 85aa2005a7787c0e28a005cd9c00f37b8c84c7b6 Mon Sep 17 00:00:00 2001 From: Nick Bowler Date: Thu, 20 Sep 2007 12:47:45 -0700 Subject: [PATCH] [PATCH] Fix IPSEC AH4 options handling commit 8ee4f391831cb96916a8e8a05f04b1c1d7dd30d8 in mainline. In testing our ESP/AH offload hardware, I discovered an issue with how AH handles mutable fields in IPv4. RFC 4302 (AH) states the following on the subject: For IPv4, the entire option is viewed as a unit; so even though the type and length fields within most options are immutable in transit, if an option is classified as mutable, the entire option is zeroed for ICV computation purposes. The current implementation does not zero the type and length fields, resulting in authentication failures when communicating with hosts that do (i.e. FreeBSD). I have tested record route and timestamp options (ping -R and ping -T) on a small network involving Windows XP, FreeBSD 6.2, and Linux hosts, with one router. In the presence of these options, the FreeBSD and Linux hosts (with the patch or with the hardware) can communicate. The Windows XP host simply fails to accept these packets with or without the patch. I have also been trying to test source routing options (using traceroute -g), but haven't had much luck getting this option to work *without* AH, let alone with. Signed-off-by: Nick Bowler Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/ah4.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c index 67a5509e26fc1..41ad4215ee0a7 100644 --- a/net/ipv4/ah4.c +++ b/net/ipv4/ah4.c @@ -46,7 +46,7 @@ static int ip_clear_mutable_options(struct iphdr *iph, __be32 *daddr) memcpy(daddr, optptr+optlen-4, 4); /* Fall through */ default: - memset(optptr+2, 0, optlen-2); + memset(optptr, 0, optlen); } l -= optlen; optptr += optlen; -- 2.47.2