[gnutls-help] gnutls_memset: use explicit_bzero

[Nikos Mavrogiannopoulos]

On Mon, 2019-03-11 at 00:02 +0100, Maciej S. Szmigiero wrote:
> > That is, use the glibc function when available and the second
> > parameter is zero.
> > 
> > Resolves #230
> > 
> > Signed-off-by: Nikos Mavrogiannopoulos <nmav at redhat.com>
> > ---(..)
> > --- a/lib/safe-memfuncs.c
> > +++ b/lib/safe-memfuncs.c
> > @@ -33,14 +30,18 @@
> >   * This function will operate similarly to memset(), but will
> >   * not be optimized out by the compiler.
> >   *
> > - * Returns: void.
> > - *
> >   * Since: 3.4.0
> >   **/
> >  void gnutls_memset(void *data, int c, size_t size)
> >  {
> > -	volatile unsigned volatile_zero = 0;
> > +	volatile unsigned volatile_zero;
> >  	volatile char *vdata = (volatile char*)data;
> > +#ifdef HAVE_EXPLICIT_BZERO
> > +	if (c == 0) {
> > +		explicit_bzero(data, size);
> 
> Shouldn't the function return here?
> 
> Because otherwise it is doing the zeroing twice:
> first time via explicit_bzero(),
> second time via a volatile trick below.

You are right. Would you like to send a merge request fixing that?

regards,
Nikos