Re: [dpdk-dev] [PATCH] net/vmxnet3: handle bad host framing

[Yong Wang <yongwang@vmware.com>]

-----Original Message-----
From: Stephen Hemminger <stephen@networkplumber.org>
Date: Tuesday, May 12, 2020 at 1:40 PM
To: Yong Wang <yongwang@vmware.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>, Stephen Hemminger <stephen@networkplumber.org>
Subject: [PATCH] net/vmxnet3: handle bad host framing

    The VMXNet3 protocol has a start-of-packet (SOP) and end-of-packet (EOP)
    marker. If there was a bug where mbuf arrived without SOP the code
    that chains the mbuf would dereference a null pointer.
    Also, record any mbuf's dropped in statistics.

    Although did the initial code no longer have access to VMware.
    Compile tested only!

    Coverity issue: 124563
    Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
    ---

<Acked-by> Yong Wang <yongwang@vmware.com>

     drivers/net/vmxnet3/vmxnet3_rxtx.c | 6 +++++-
     1 file changed, 5 insertions(+), 1 deletion(-)

    diff --git a/drivers/net/vmxnet3/vmxnet3_rxtx.c b/drivers/net/vmxnet3/vmxnet3_rxtx.c
    index dd99684bee4d..73e270f30f00 100644
    --- a/drivers/net/vmxnet3/vmxnet3_rxtx.c
    +++ b/drivers/net/vmxnet3/vmxnet3_rxtx.c
    @@ -950,13 +950,17 @@ vmxnet3_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)

     			RTE_ASSERT(rxd->btype == VMXNET3_RXD_BTYPE_BODY);

    -			if (rxm->data_len) {
    +			if (likely(start && rxm->data_len > 0)) {
     				start->pkt_len += rxm->data_len;
     				start->nb_segs++;

     				rxq->last_seg->next = rxm;
     				rxq->last_seg = rxm;
     			} else {
    +				PMD_RX_LOG(ERR, "Error received empty or out of order frame.");
    +				rxq->stats.drop_total++;
    +				rxq->stats.drop_err++;
    +
     				rte_pktmbuf_free_seg(rxm);
     			}
     		}
    -- 
    2.20.1