From: Jere Leppänen <jere.leppanen@xxxxxxxxx>
Date: Wed, 20 May 2020 18:15:31 +0300
> Commit bdf6fa52f01b ("sctp: handle association restarts when the
> socket is closed.") starts shutdown when an association is restarted,
> if in SHUTDOWN-PENDING state and the socket is closed. However, the
> rationale stated in that commit applies also when in SHUTDOWN-SENT
> state - we don't want to move an association to ESTABLISHED state when
> the socket has been closed, because that results in an association
> that is unreachable from user space.
>
> The problem scenario:
>
> 1. Client crashes and/or restarts.
>
> 2. Server (using one-to-one socket) calls close(). SHUTDOWN is lost.
>
> 3. Client reconnects using the same addresses and ports.
>
> 4. Server's association is restarted. The association and the socket
> move to ESTABLISHED state, even though the server process has
> closed its descriptor.
>
> Also, after step 4 when the server process exits, some resources are
> leaked in an attempt to release the underlying inet sock structure in
> ESTABLISHED state:
>
> IPv4: Attempt to release TCP socket in state 1 00000000377288c7
>
> Fix by acting the same way as in SHUTDOWN-PENDING state. That is, if
> an association is restarted in SHUTDOWN-SENT state and the socket is
> closed, then start shutdown and don't move the association or the
> socket to ESTABLISHED state.
>
> Fixes: bdf6fa52f01b ("sctp: handle association restarts when the socket is closed.")
> Signed-off-by: Jere Leppänen <jere.leppanen@xxxxxxxxx>
Applied and queued up for -stable, thanks.
