net: bridge: enfore alignment for ethernet address

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>
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>

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 7501be4..2130fe0 100644 (file)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -217,8 +217,8 @@ 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 {