[PATCH 4.8 05/49] ip6_tunnel: Clear IP6CB in ip6tunnel_xmit()

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.8 05/49] ip6_tunnel: Clear IP6CB in ip6tunnel_xmit()
Date	2016-11-19 10:30 +0100
Message-ID	<sFa8a-33e-25@gated-at.bofh.it> (permalink)
References	<sFa89-33e-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eli Cooper <elicooper@gmx.com>


[ Upstream commit 23f4ffedb7d751c7e298732ba91ca75d224bc1a6 ]

skb->cb may contain data from previous layers. In the observed scenario,
the garbage data were misinterpreted as IP6CB(skb)->frag_max_size, so
that small packets sent through the tunnel are mistakenly fragmented.

This patch unconditionally clears the control buffer in ip6tunnel_xmit(),
which affects ip6_tunnel, ip6_udp_tunnel and ip6_gre. Currently none of
these tunnels set IP6CB(skb)->flags, otherwise it needs to be done earlier.

Cc: stable@vger.kernel.org
Signed-off-by: Eli Cooper <elicooper@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/ip6_tunnel.h |    1 +
 1 file changed, 1 insertion(+)

--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -145,6 +145,7 @@ static inline void ip6tunnel_xmit(struct
 {
 	int pkt_len, err;
 
+	memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
 	pkt_len = skb->len - skb_inner_network_offset(skb);
 	err = ip6_local_out(dev_net(skb_dst(skb)->dev), sk, skb);
 	if (unlikely(net_xmit_eval(err)))

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[PATCH 4.8 05/49] ip6_tunnel: Clear IP6CB in ip6tunnel_xmit() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-19 10:30 +0100

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