Re: [PATCH] bridge: don't try to update timers in case of broken MLD queries

Stephen Hemminger
2013-08-05T22:42:28Z

On Tue, 6 Aug 2013 00:32:05 +0200
Linus Lüssing <linus.luessing@web.de> wrote:

> Currently we are reading an uninitialized value for the max_delay
> variable when snooping an MLD query message of invalid length and would
> update our timers with that.
>
> Fixing this by simply ignoring such broken MLD queries (just like we do
> for IGMP already).
>
> This is a regression introduced by:
> "bridge: disable snooping if there is no querier" (b00589af3b04)
>
> Reported-by: Paul Bolle <pebolle@tiscali.nl>
> Signed-off-by: Linus Lüssing <linus.luessing@web.de>
> ---
> net/bridge/br_multicast.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index 61c5e81..08e576a 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -1195,7 +1195,7 @@ static int br_ip6_multicast_query(struct net_bridge *br,
> max_delay = msecs_to_jiffies(ntohs(mld->mld_maxdelay));
> if (max_delay)
> group = &mld->mld_mca;
> - } else if (skb->len >= sizeof(*mld2q)) {
> + } else {
> if (!pskb_may_pull(skb, sizeof(*mld2q))) {
> err = -EINVAL;
> goto out;

Why not use else if here, other than that looks great.