net: bridge: enfore alignment for ethernet address

[ 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>

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index e870cfc85b1476e0cd9456a51e6ee161d962d4f3..14ff034e561c5118980817965c4481a0336ff081 100644 (file)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -190,8 +190,8 @@ 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