[PATCH] net: bridge: enfore alignment for ethernet address

* [PATCH] net: bridge: enfore alignment for ethernet address
@ 2020-06-25  6:54 Thomas Martitz
  2020-06-25 11:54 ` Nikolay Aleksandrov
  2020-06-25 12:26 ` [PATCH v2] " Thomas Martitz
  0 siblings, 2 replies; 6+ messages in thread
From: Thomas Martitz @ 2020-06-25  6:54 UTC (permalink / raw)
  To: netdev
  Cc: Thomas Martitz, Roopa Prabhu, Nikolay Aleksandrov,
	David S . Miller, Jakub Kicinski, Felix Fietkau, stable

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>
---
 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 7501be4eeba0..22cb2f1993ef 100644
--- 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]; /* 2-byte aligned */
 	unsigned char			flags;
-	unsigned char			eth_addr[ETH_ALEN];
 };
 
 struct net_bridge_mdb_entry {
-- 
2.27.0


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