Re: [PATCH] RDMA: fix use-after-free in rxe_queue_cleanup

[Zhu Yanjun]

On Mon, Nov 22, 2021 at 4:22 AM Pavel Skripkin <paskripkin@xxxxxxxxx> wrote:
>
> On error handling path in rxe_qp_from_init() qp->sq.queue is freed and
> then rxe_create_qp() will drop last reference to this object. qp clean
> up function will try to free this queue one time and it causes UAF bug.
>
> Fix it by zeroing queue pointer after freeing queue in
> rxe_qp_from_init().
>
> Fixes: 514aee660df4 ("RDMA: Globally allocate and release QP memory")
> Reported-by: syzbot+aab53008a5adf26abe91@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>

Reviewed-by: Zhu Yanjun <zyjzyj2000@xxxxxxxxx>

Thanks a lot.
Zhu Yanjun

> ---
>  drivers/infiniband/sw/rxe/rxe_qp.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
> index 975321812c87..54b8711321c1 100644
> --- a/drivers/infiniband/sw/rxe/rxe_qp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_qp.c
> @@ -359,6 +359,7 @@ int rxe_qp_from_init(struct rxe_dev *rxe, struct rxe_qp *qp, struct rxe_pd *pd,
>
>  err2:
>         rxe_queue_cleanup(qp->sq.queue);
> +       qp->sq.queue = NULL;
>  err1:
>         qp->pd = NULL;
>         qp->rcq = NULL;
> --
> 2.33.1
>