[dpdk-dev] [dpdk-stable] [PATCH] examples/vhost: fix potential overflow in args process

[David Marchand]

On Mon, Apr 19, 2021 at 7:59 AM Cheng Jiang <Cheng1.jiang at intel.com> wrote:
>
> Add args length check to fix potential overflow issue.
>
> Coverity issue: 363741
> Fixes: 965b06f0358 ("examples/vhost: enhance getopt_long usage")
> Cc: stable at dpdk.org

No need for Cc: stable since this issue only affects the current release.

>
> Signed-off-by: Cheng Jiang <Cheng1.jiang at intel.com>

It should indeed fix the coverity report but this limit does not make sense.
Could you make dma_type point at either optarg (it should be fine as
we only read this string)?

Something like (untested):

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index 2ca7d98c58..158e5e9a8a 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -55,9 +55,6 @@

 #define INVALID_PORT_ID 0xFF

-/* Maximum long option length for option parsing. */
-#define MAX_LONG_OPT_SZ 64
-
 /* mask of enabled ports */
 static uint32_t enabled_port_mask = 0;

@@ -97,7 +94,7 @@ static int builtin_net_driver;

 static int async_vhost_driver;

-static char dma_type[MAX_LONG_OPT_SZ];
+static char *dma_type;

 /* Specify timeout (in useconds) between retries on RX. */
 static uint32_t burst_rx_delay_time = BURST_RX_WAIT_US;
@@ -201,7 +198,7 @@ struct vhost_bufftable *vhost_txbuff[RTE_MAX_LCORE
* MAX_VHOST_DEVICE];
 static inline int
 open_dma(const char *value)
 {
-       if (strncmp(dma_type, "ioat", 4) == 0)
+       if (dma_type != NULL && strncmp(dma_type, "ioat", 4) == 0)
                return open_ioat(value);

        return -1;
@@ -669,7 +666,7 @@ us_vhost_parse_args(int argc, char **argv)
                        break;

                case OPT_DMA_TYPE_NUM:
-                       strcpy(dma_type, optarg);
+                       dma_type = optarg;
                        break;

                case OPT_DMAS_NUM:
@@ -1472,7 +1469,7 @@ new_device(int vid)
                struct rte_vhost_async_features f;
                struct rte_vhost_async_channel_ops channel_ops;

-               if (strncmp(dma_type, "ioat", 4) == 0) {
+               if (dma_type != NULL && strncmp(dma_type, "ioat", 4) == 0) {
                        channel_ops.transfer_data = ioat_transfer_data_cb;
                        channel_ops.check_completed_copies =
                                ioat_check_completed_copies_cb;



-- 
David Marchand