[gnutls-help] gnutls_memset: use explicit_bzero

[Maciej S. Szmigiero]

On 27.03.2019 08:24, Nikos Mavrogiannopoulos wrote:
> 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?

While I don't have a gitlab account to open a merge request there
I have attached a patch made by git-format-patch.
Hope this way will work, too.

> regards,
> Nikos

Thanks,
Maciej
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