[dpdk-dev] [PATCH] net/tap: fix coverity warning on strncpy

[Bruce Richardson]

On Fri, Feb 17, 2017 at 03:05:40PM +0000, Wiles, Keith wrote:
> 
> > On Feb 17, 2017, at 9:02 AM, Richardson, Bruce <bruce.richardson at intel.com> wrote:
> > 
> > On Fri, Feb 17, 2017 at 08:44:26AM -0600, Keith Wiles wrote:
> >> Calling strncpy with a maximum size argument of 16 bytes on destination
> >> array "ifr.ifr_ifrn.ifrn_name" of size 16 bytes might leave the
> >> destination string unterminated.
> >> 
> >> Signed-off-by: Keith Wiles <keith.wiles at intel.com>
> >> ---
> >> drivers/net/tap/rte_eth_tap.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >> 
> >> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
> >> index efc4426..f9938d7 100644
> >> --- a/drivers/net/tap/rte_eth_tap.c
> >> +++ b/drivers/net/tap/rte_eth_tap.c
> >> @@ -297,7 +297,7 @@ tap_link_set_flags(struct pmd_internals *pmd, short flags, int add)
> >> 		return -1;
> >> 	}
> >> 	memset(&ifr, 0, sizeof(ifr));
> >> -	strncpy(ifr.ifr_name, pmd->name, IFNAMSIZ);
> >> +	strncpy(ifr.ifr_name, pmd->name, IFNAMSIZ-1);
> > This is why I always prefer to use snprintf for copying strings, you
> > can't avoid null terminating.
> 
> Normally I use snprintf to not sure why I reverted to strncpy. Maybe leftover from a previous driver I used as the template.
> 
Is there a case to be made that DPDK should provide a strlcpy function
in the linuxapp EAL? [Assuming we don't want a dependency on libbsd?]
I find strncpy a horribly-error prone function to use - worse than
strcpy, since it gives a false sense of safety.

/Bruce