Re: [PATCH 2.6.32 29/62] sctp: Fix race between OOTB responce and route removal

From: Willy Tarreau
Date: Tue Sep 15 2015 - 03:43:28 EST


On Tue, Sep 15, 2015 at 03:26:44AM +0100, Ben Hutchings wrote:
> On Sun, 2015-09-13 at 00:56 +0200, Willy Tarreau wrote:
> > 2.6.32-longterm review patch. If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
> >
> > [ Upstream commit 29c4afc4e98f4dc0ea9df22c631841f9c220b944 ]
> >
> > There is NULL pointer dereference possible during statistics update if the route
> > used for OOTB responce is removed at unfortunate time. If the route exists when
> > we receive OOTB packet and we finally jump into sctp_packet_transmit() to send
> > ABORT, but in the meantime route is removed under our feet, we take "no_route"
> > path and try to update stats with IP_INC_STATS(sock_net(asoc->base.sk), ...).
> [...]
> > [bwh: Backported to 3.2: sctp alway uses init_net]
> > Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
> [...]
>
> This doesn't make sense in 2.6.32 and it didn't make sense for me to
> apply it to 3.2 either! Since sctp is not using asoc to look up a net
> namespace here, the null pointer doesn't get dereferenced.

Perfect, I'm dropping it now.
Thanks,
Willy

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