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    Subject[PATCH 3.12 08/33] bridge: mdb: zero out the local br_ip variable before use
    Date
    From: Nikolay Aleksandrov <razor@blackwall.org>

    3.12-stable review patch. If anyone has any objections, please let me know.

    ===============

    [ Upstream commit f1158b74e54f2e2462ba5e2f45a118246d9d5b43 ]

    Since commit b0e9a30dd669 ("bridge: Add vlan id to multicast groups")
    there's a check in br_ip_equal() for a matching vlan id, but the mdb
    functions were not modified to use (or at least zero it) so when an
    entry was added it would have a garbage vlan id (from the local br_ip
    variable in __br_mdb_add/del) and this would prevent it from being
    matched and also deleted. So zero out the whole local ip var to protect
    ourselves from future changes and also to fix the current bug, since
    there's no vlan id support in the mdb uapi - use always vlan id 0.
    Example before patch:
    root@debian:~# bridge mdb add dev br0 port eth1 grp 239.0.0.1 permanent
    root@debian:~# bridge mdb
    dev br0 port eth1 grp 239.0.0.1 permanent
    root@debian:~# bridge mdb del dev br0 port eth1 grp 239.0.0.1 permanent
    RTNETLINK answers: Invalid argument

    After patch:
    root@debian:~# bridge mdb add dev br0 port eth1 grp 239.0.0.1 permanent
    root@debian:~# bridge mdb
    dev br0 port eth1 grp 239.0.0.1 permanent
    root@debian:~# bridge mdb del dev br0 port eth1 grp 239.0.0.1 permanent
    root@debian:~# bridge mdb

    Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
    Fixes: b0e9a30dd669 ("bridge: Add vlan id to multicast groups")
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Jiri Slaby <jslaby@suse.cz>
    ---
    net/bridge/br_mdb.c | 2 ++
    1 file changed, 2 insertions(+)

    diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c
    index b7b1914dfa25..13421bf464c0 100644
    --- a/net/bridge/br_mdb.c
    +++ b/net/bridge/br_mdb.c
    @@ -370,6 +370,7 @@ static int __br_mdb_add(struct net *net, struct net_bridge *br,
    if (!p || p->br != br || p->state == BR_STATE_DISABLED)
    return -EINVAL;

    + memset(&ip, 0, sizeof(ip));
    ip.proto = entry->addr.proto;
    if (ip.proto == htons(ETH_P_IP))
    ip.u.ip4 = entry->addr.u.ip4;
    @@ -416,6 +417,7 @@ static int __br_mdb_del(struct net_bridge *br, struct br_mdb_entry *entry)
    if (!netif_running(br->dev) || br->multicast_disabled)
    return -EINVAL;

    + memset(&ip, 0, sizeof(ip));
    ip.proto = entry->addr.proto;
    if (ip.proto == htons(ETH_P_IP)) {
    if (timer_pending(&br->ip4_querier.timer))
    --
    2.5.2


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