On Fri, Oct 28, 2016 at 06:10:52PM +0800, Xin Long wrote:
> In sctp_transport_lookup_process(), Commit 1cceda784980 ("sctp: fix
> the issue sctp_diag uses lock_sock in rcu_read_lock") moved cb() out
> of rcu lock, but it put transport and hold assoc instead, and ignore
> that cb() still uses transport. It may cause a use-after-free issue.
>
> This patch is to hold transport instead of assoc there.
>
> Fixes: 1cceda784980 ("sctp: fix the issue sctp_diag uses lock_sock in
> rcu_read_lock")
> Signed-off-by: Xin Long <lucien....@gmail.com>
> ---
> net/sctp/socket.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 9fbb6fe..71b75f9 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -4480,12 +4480,9 @@ int sctp_transport_lookup_process(int (*cb)(struct
> sctp_transport *, void *),
> if (!transport || !sctp_transport_hold(transport))
> goto out;
>
> - sctp_association_hold(transport->asoc);
> - sctp_transport_put(transport);
> -
> rcu_read_unlock();
> err = cb(transport, p);
> - sctp_association_put(transport->asoc);
> + sctp_transport_put(transport);
>
> out:
> return err;
> --
> 2.1.0
>
> --
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>
Acked-by: Neil Horman <nhor...@tuxdriver.com>
