[dpdk-dev] [PATCH] net/ice: fix integer overflow when computing max_pkt_len

[Tudor Cornea <tudor.cornea@gmail.com>]

Greetings,

Please review the following patch for the dpdk-next-net-intel branch.

The len variable, used in the computation of max_pkt_len could overflow,
if used to store the result of the following computation:

ICE_SUPPORT_CHAIN_NUM * rxq->rx_buf_len

Since, we could define the mbuf size to have a large value (i.e 13312),
and ICE_SUPPORT_CHAIN_NUM is defined as 5, the computation mentioned
above could potentially result in a value which might be bigger than
MAX_USHORT.

The result will be that Jumbo Frames will not work properly

Signed-off-by: Tudor Cornea <tudor.cornea@keysight.com>
---
 drivers/net/ice/ice_dcf_ethdev.c | 7 ++++---
 drivers/net/ice/ice_rxtx.c       | 6 +++---
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ice/ice_dcf_ethdev.c
b/drivers/net/ice/ice_dcf_ethdev.c
index b937cbb..f73dc80 100644
--- a/drivers/net/ice/ice_dcf_ethdev.c
+++ b/drivers/net/ice/ice_dcf_ethdev.c
@@ -54,13 +54,14 @@ ice_dcf_init_rxq(struct rte_eth_dev *dev, struct
ice_rx_queue *rxq)
        struct ice_dcf_adapter *dcf_ad = dev->data->dev_private;
        struct rte_eth_dev_data *dev_data = dev->data;
        struct iavf_hw *hw = &dcf_ad->real_hw.avf;
-       uint16_t buf_size, max_pkt_len, len;
+       uint16_t buf_size, max_pkt_len;

        buf_size = rte_pktmbuf_data_room_size(rxq->mp) -
RTE_PKTMBUF_HEADROOM;
        rxq->rx_hdr_len = 0;
        rxq->rx_buf_len = RTE_ALIGN(buf_size, (1 << ICE_RLAN_CTX_DBUF_S));
-       len = ICE_SUPPORT_CHAIN_NUM * rxq->rx_buf_len;
-       max_pkt_len = RTE_MIN(len,
dev->data->dev_conf.rxmode.max_rx_pkt_len);
+       max_pkt_len = RTE_MIN((uint32_t)
+                             ICE_SUPPORT_CHAIN_NUM * rxq->rx_buf_len,
+                             dev->data->dev_conf.rxmode.max_rx_pkt_len);

        /* Check if the jumbo frame and maximum packet length are set
         * correctly.
diff --git a/drivers/net/ice/ice_rxtx.c b/drivers/net/ice/ice_rxtx.c
index fc9bb5a..20352b0 100644
--- a/drivers/net/ice/ice_rxtx.c
+++ b/drivers/net/ice/ice_rxtx.c
@@ -258,7 +258,7 @@ ice_program_hw_rx_queue(struct ice_rx_queue *rxq)
        struct rte_eth_dev_data *dev_data = rxq->vsi->adapter->pf.dev_data;
        struct ice_rlan_ctx rx_ctx;
        enum ice_status err;
-       uint16_t buf_size, len;
+       uint16_t buf_size;
        struct rte_eth_rxmode *rxmode = &dev_data->dev_conf.rxmode;
        uint32_t rxdid = ICE_RXDID_COMMS_OVS;
        uint32_t regval;
@@ -268,8 +268,8 @@ ice_program_hw_rx_queue(struct ice_rx_queue *rxq)
                              RTE_PKTMBUF_HEADROOM);
        rxq->rx_hdr_len = 0;
        rxq->rx_buf_len = RTE_ALIGN(buf_size, (1 << ICE_RLAN_CTX_DBUF_S));
-       len = ICE_SUPPORT_CHAIN_NUM * rxq->rx_buf_len;
-       rxq->max_pkt_len = RTE_MIN(len,
+       rxq->max_pkt_len = RTE_MIN((uint32_t)
+                                  ICE_SUPPORT_CHAIN_NUM * rxq->rx_buf_len,

 dev_data->dev_conf.rxmode.max_rx_pkt_len);

        if (rxmode->offloads & DEV_RX_OFFLOAD_JUMBO_FRAME) {
-- 
2.7.4