On Fri, Mar 08, 2019 at 03:49:16PM +0800, Xin Long wrote:
> syzbot reported a NULL-ptr deref caused by that sched->init() in
> sctp_stream_init() set stream->rr_next = NULL.
>
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> RIP: 0010:sctp_sched_rr_dequeue+0xd3/0x170 net/sctp/stream_sched_rr.c:141
> Call Trace:
> sctp_outq_dequeue_data net/sctp/outqueue.c:90 [inline]
> sctp_outq_flush_data net/sctp/outqueue.c:1079 [inline]
> sctp_outq_flush+0xba2/0x2790 net/sctp/outqueue.c:1205
>
> All sched info is saved in sout->ext now, in sctp_stream_init()
> sctp_stream_alloc_out() will not change it, there's no need to
> call sched->init() again, since sctp_outq_init() has already
> done it.
>
> Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
> Reported-by: syzbot+4c9934f20522c0efd657@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> ---
> net/sctp/stream.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/net/sctp/stream.c b/net/sctp/stream.c
> index 2936ed1..3b47457 100644
> --- a/net/sctp/stream.c
> +++ b/net/sctp/stream.c
> @@ -230,8 +230,6 @@ int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
> for (i = 0; i < stream->outcnt; i++)
> SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
>
> - sched->init(stream);
> -
> in:
> sctp_stream_interleave_init(stream);
> if (!incnt)
> --
> 2.1.0
>
>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
