Re: [dpdk-dev] [PATCH] net/bnxt: fix a possible stack smashing

[Ajit Khaparde <ajit.khaparde@broadcom.com>]

On Tue, May 5, 2020 at 8:29 PM Yuan Linsi <yuanlinsi01@baidu.com> wrote:

> From: Linsi Yuan <yuanlinsi01@baidu.com>
>
> We see a stack smashing as a result of defensive code missing. Once the
> nb_pkts is less than RTE_BNXT_DESCS_PER_LOOP, it will be modified to
> zero after doing a floor align, and we can not exit the following
> receiving packets loop. And the buffers will be overwrite, then the
> stack frame was ruined.
>
> Fix the problem by adding defensive code, once the nb_pkts is zero, just
> directly return with no packets.
>
> Fixes: bc4a000f2 ("net/bnxt: implement SSE vector mode")
> Cc: stable@dpdk.org
>
> Signed-off-by: Linsi Yuan <yuanlinsi01@baidu.com>
> Signed-off-by: Dongsheng Rong <rongdongsheng@baidu.com>
>
Thanks. I updated the earlier version [1] with this Signed-off.

[1] https://patchwork.dpdk.org/patch/69604/


> ---
>  drivers/net/bnxt/bnxt_rxtx_vec_sse.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/bnxt/bnxt_rxtx_vec_sse.c
> b/drivers/net/bnxt/bnxt_rxtx_vec_sse.c
> index d0e7910e7..8f73add9b 100644
> --- a/drivers/net/bnxt/bnxt_rxtx_vec_sse.c
> +++ b/drivers/net/bnxt/bnxt_rxtx_vec_sse.c
> @@ -233,8 +233,13 @@ bnxt_recv_pkts_vec(void *rx_queue, struct rte_mbuf
> **rx_pkts,
>         /* Return no more than RTE_BNXT_MAX_RX_BURST per call. */
>         nb_pkts = RTE_MIN(nb_pkts, RTE_BNXT_MAX_RX_BURST);
>
> -       /* Make nb_pkts an integer multiple of RTE_BNXT_DESCS_PER_LOOP */
> +       /*
> +        * Make nb_pkts an integer multiple of RTE_BNXT_DESCS_PER_LOOP.
> +        * nb_pkts < RTE_BNXT_DESCS_PER_LOOP, just return no packet
> +        */
>         nb_pkts = RTE_ALIGN_FLOOR(nb_pkts, RTE_BNXT_DESCS_PER_LOOP);
> +       if (!nb_pkts)
> +               return 0;
>
>         /* Handle RX burst request */
>         while (1) {
> --
> 2.11.0
>
>