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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.19 35/50] net: bridge: stp: dont cache eth dest pointer before skb pull
Date:   Fri, 26 Jul 2019 17:25:10 +0200
Message-Id: <20190726152304.248021797@linuxfoundation.org>
In-Reply-To: <20190726152300.760439618@linuxfoundation.org>
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From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>

[ Upstream commit 2446a68ae6a8cee6d480e2f5b52f5007c7c41312 ]

Don't cache eth dest pointer before calling pskb_may_pull.

Fixes: cf0f02d04a83 ("[BRIDGE]: use llc for receiving STP packets")
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/bridge/br_stp_bpdu.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/net/bridge/br_stp_bpdu.c
+++ b/net/bridge/br_stp_bpdu.c
@@ -147,7 +147,6 @@ void br_send_tcn_bpdu(struct net_bridge_
 void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
 		struct net_device *dev)
 {
-	const unsigned char *dest = eth_hdr(skb)->h_dest;
 	struct net_bridge_port *p;
 	struct net_bridge *br;
 	const unsigned char *buf;
@@ -176,7 +175,7 @@ void br_stp_rcv(const struct stp_proto *
 	if (p->state == BR_STATE_DISABLED)
 		goto out;
 
-	if (!ether_addr_equal(dest, br->group_addr))
+	if (!ether_addr_equal(eth_hdr(skb)->h_dest, br->group_addr))
 		goto out;
 
 	if (p->flags & BR_BPDU_GUARD) {