Re: [PATCH 3/3] app/pdump: fix string overflow

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 6/21/2016 4:18 PM, Reshma Pattan wrote:
> using source length in strncpy can cause destination
> overflow if destination length is not big enough to
> handle the source string. Changes are made to use destination
> size instead of source length in strncpy.
> 
> Coverity issue 127351: string overflow
> 
> Fixes: caa7028276b8 ("app/pdump: add tool for packet capturing")
> 
> Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
> ---
>  app/pdump/main.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/app/pdump/main.c b/app/pdump/main.c
> index f8923b9..af92ef3 100644
> --- a/app/pdump/main.c
> +++ b/app/pdump/main.c
> @@ -217,12 +217,12 @@ parse_rxtxdev(const char *key, const char *value, void *extra_args)
>  	struct pdump_tuples *pt = extra_args;
>  
>  	if (!strcmp(key, PDUMP_RX_DEV_ARG)) {
> -		strncpy(pt->rx_dev, value, strlen(value));
> +		strncpy(pt->rx_dev, value, sizeof(pt->rx_dev)-1);

I guess size-1 is to give room for terminating null byte, but for this
case is it guarantied that pt->rx_dev last byte is NULL?