Re: [HACKERS] GnuTLS support

Hi,

On 09/04/2017 04:24 PM, Bruce Momjian wrote:
> On Fri, Sep  1, 2017 at 12:09:35PM -0400, Robert Haas wrote:
>> I think that what this shows is that the current set of GUCs is overly
>> OpenSSL-centric.  We created a set of GUCs that are actually specific
>> to one particular implementation but named them as if they were
>> generic.  My idea about this would be to actually rename the existing
>> GUCs to start with "openssl" rather than "ssl", and then add new GUCs
>> as needed for other SSL implementations.
>>
>> Depending on what we think is best, GUCs for an SSL implementation
>> other than the one against which we compiled can either not exist at
>> all, or can exist but be limited to a single value (e.g. "none", as we
>> currently do when the compile has no SSL support at all).  Also, we
>> could add a read-only GUC with a name like ssl_library that exposes
>> the name of the underlying SSL implementation - none, openssl, gnutls,
>> or whatever.
>>
>> I think if we go the route of insisting that every SSL implementation
>> has to use the existing GUCs, we're just trying to shove a square peg
>> into a round hole, and there's no real benefit for users.  If the
>> string that has to be stuffed into ssl_ciphers differs based on which
>> library was chosen at compile time, then you can't have a uniform
>> default configuration for all libraries anyway.  I think it'll be
>> easier to explain and document this if there's separate documentation
>> for openssl_ciphers, gnutls_ciphers, etc. rather than one giant
>> documentation section that tries to explain every implementation
>> separately.
>
> I am worried about having 3x version of TLS controls in
> postgresql.conf, and only one set being active. Perhaps we need to
> break out the TLS config to separate files or something. Anyway, this
> needs more thought.
>

Well, people won't be able to set the inactive options, just like you
can't set ssl=on when you build without OpenSSL support. But perhaps we
could simply not include the inactive options into the config file, no?

I don't see how breaking the TLS config into separate files improves the
situation - instead of dealing with GUCs in a single file you'll be
dealing with the same GUCs in multiple files. No?