Re: default SSL compression (was: libpq compression)

On Wed, Jan 02, 2013 at 02:03:20PM +0100, Magnus Hagander wrote:
> On Wed, Jan 2, 2013 at 1:15 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > So +1 for changing it to "DEFAULT" from me, too. There's no reason to
> > think we know more about this than the OpenSSL authors.
>
> The DEFAULT value in OpenSSL 1.0 means "ALL:!aNULL:!eNULL".
>
> Researching some more, this might cause a problem actually, which
> would explain some of the things that are in our default. For example,
> an ADH algorithm doesn't use certificates - but it uses DH parameters,
> so it likely won't work anyway. EDH uses certs, but also requires DH
> parameters.
>
> Maybe what we nede is "DEFAULT:!ADH:@STRENGTH" as the default?

I understand aNULL to include ADH.

> The other difference is that our current string denies 40 and 56 bit
> encryptions (low and export strenghts). Do we stll want to do that?

On the one hand, those seem bad to permit by default in 2013. On the other
hand, if so, why hasn't OpenSSL removed them from DEFAULT? Perhaps it has
backward-compatibility concerns that wouldn't apply to us by virtue of having
disabled them for some time. Sounds reasonable to continue disabling them.