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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Thomas Martitz <t.martitz@avm.de>,
        Roopa Prabhu <roopa@cumulusnetworks.com>,
        Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, Felix Fietkau <nbd@nbd.name>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH 4.19 019/131] net: bridge: enfore alignment for ethernet address
Date:   Mon, 29 Jun 2020 11:33:10 -0400
Message-Id: <20200629153502.2494656-20-sashal@kernel.org>
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From: Thomas Martitz <t.martitz@avm.de>

[ Upstream commit db7202dec92e6caa2706c21d6fc359af318bde2e ]

The eth_addr member is passed to ether_addr functions that require
2-byte alignment, therefore the member must be properly aligned
to avoid unaligned accesses.

The problem is in place since the initial merge of multicast to unicast:
commit 6db6f0eae6052b70885562e1733896647ec1d807 bridge: multicast to unicast

Fixes: 6db6f0eae605 ("bridge: multicast to unicast")
Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
Cc: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Martitz <t.martitz@avm.de>
Acked-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_private.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 11ed2029985fd..33b8222db75c4 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -202,8 +202,8 @@ struct net_bridge_port_group {
 	struct rcu_head			rcu;
 	struct timer_list		timer;
 	struct br_ip			addr;
+	unsigned char			eth_addr[ETH_ALEN] __aligned(2);
 	unsigned char			flags;
-	unsigned char			eth_addr[ETH_ALEN];
 };
 
 struct net_bridge_mdb_entry
-- 
2.25.1