Commit 935a9749 authored Oct 01, 2017 by Xin Long Committed by David S. Miller Oct 01, 2017

ip_gre: get key from session_id correctly in erspan_rcv



erspan only uses the first 10 bits of session_id as the key to look
up the tunnel. But in erspan_rcv, it missed 'session_id & ID_MASK'
when getting the key from session_id.

If any other flag is also set in session_id in a packet, it would
fail to find the tunnel due to incorrect key in erspan_rcv.

This patch is to add 'session_id & ID_MASK' there and also remove
the unnecessary variable session_id.

Fixes: 84e54fe0 ("gre: introduce native tunnel support for ERSPAN")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent aad06212

net/ipv4/ip_gre.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -259,7 +259,6 @@ static int erspan_rcv(struct sk_buff skb, struct tnl_ptk_info tpi,
		struct ip_tunnel *tunnel;
		struct erspanhdr *ershdr;
		const struct iphdr *iph;
		__be32 session_id;
		__be32 index;
		int len;

		@@ -275,8 +274,7 @@ static int erspan_rcv(struct sk_buff skb, struct tnl_ptk_info tpi,
		/* The original GRE header does not have key field,
		* Use ERSPAN 10-bit session ID as key.
		*/
		session_id = cpu_to_be32(ntohs(ershdr->session_id));
		tpi->key = session_id;
		tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
		index = ershdr->md.index;
		tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
		tpi->flags \| TUNNEL_KEY,

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