[CentOS] Fix for CVE-2020-1971 on CentOS 6.10

> Simon Matter wrote:
>>Since security updates for CentOS 6 are not provided anymore, I've
>> decided
>>to try my best to address CVE-2020-1971 and I welcome others to do the
>>same for this and other new issues which may come up.
>
> Thanks to Simon for doing this.
>
> I made my own patch which ended up the same as Simon's apart from
> whitespace and formatting.  It's been deployed on a CentOS 6 system that
> can't be upgraded yet due to... reasons.  Seems to work in the limited
> testing I've done.

Thanks Ron for your feedback! It gives us more confidence that the patch
is correct.

I'm also using it on a number of systems without issues.

Regards,
Simon