[BRIDGE]: Unaligned access when comparing ethernet addresses

compare_ether_addr() implicitly requires that the addresses
passed are 2-bytes aligned in memory.

This is not true for br_stp_change_bridge_id() and
br_stp_recalculate_bridge_id() in which one of the addresses
is unsigned char *, and thus may not be 2-bytes aligned.

Signed-off-by: Evgeny Kravtsunov <emkravts@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Pavel Emelianov <xemul@openvz.org>

diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
index 58d13f2..a285897 100644 (file)
--- a/net/bridge/br_stp_if.c
+++ b/net/bridge/br_stp_if.c
@@ -126,7 +126,9 @@ void br_stp_disable_port(struct net_bridge_port *p)
 /* called under bridge lock */
 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 {
-       unsigned char oldaddr[6];
+       /* should be aligned on 2 bytes for compare_ether_addr() */
+       unsigned short oldaddr_aligned[ETH_ALEN >> 1];
+       unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
        struct net_bridge_port *p;
        int wasroot;
 
@@ -151,11 +153,14 @@ void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
                br_become_root_bridge(br);
 }
 
-static const unsigned char br_mac_zero[6];
+/* should be aligned on 2 bytes for compare_ether_addr() */
+static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 
 /* called under bridge lock */
 void br_stp_recalculate_bridge_id(struct net_bridge *br)
 {
+       const unsigned char *br_mac_zero =
+                       (const unsigned char *)br_mac_zero_aligned;
        const unsigned char *addr = br_mac_zero;
        struct net_bridge_port *p;