On Sat, Nov 30, 2013 at 03:46:06AM -0500, Jeffrey Walton wrote:
> >> I believe the "standard" way of achieving TLS1.0 and above is to use
> >> the SSLv23_client_method() and then remove the SSL protocols with
> >> SSL_OP_NO_SSLv2 and SSL_OP_NO_SSLv3. I have to use handwaiving around
> >> "standard" because I don't believe its documented anywhere (one of the
> >> devs told me its the standard way to do it.).
> >
> > Indeed - Python ssl module seems to achieve TLSv1.1 and it uses
> > SSLv23_method(). But still no TLSv1.2.
> It sounds like they are using the TLSv1_1_method(). You can check it
> with Wireshark. The Client Hello will advertise the highest version of
> the protocol supported. See http://postimg.org/image/e4mk3nhhl/.
No, they are using SSLv23_method(). And I can confirm - I did small
C program with SSLv23_method and SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3,
and it requests up to TLSv1.1.
> If Python is not advertising TLS 1.2, then they should use the
> SSLv23_method() with SSL_OP_NO_SSLv2, SSL_OP_NO_SSLv3 and
> SSL_OP_NO_TLSv1. That will get them TLS 1.1 and above. From ssl.h,
> around line 605:
>
> #define SSL_OP_NO_SSLv2 0x01000000L
> #define SSL_OP_NO_SSLv3 0x02000000L
> #define SSL_OP_NO_TLSv1 0x04000000L
> #define SSL_OP_NO_TLSv1_2 0x08000000L
> #define SSL_OP_NO_TLSv1_1 0x10000000L
>
> If you only want TLS 1.1 and 1.2, you can further trim your preferred
> cipher list. TLS 1.1 did not add any ciphers, so your list might look
> like (the TLS 1.0 ciphers can be used in TLS 1.1):
I could not get TLSv1.1+ with that. But I'm working against
Ubuntu 12.04 default OpenSSL. I'll try with other versions too.
> Personally, I'd like to drop TLS 1.0 (even though the complaints are
> mainly academic). But I think its still needed for interop. I've never
> rolled a system without it enabled.
Good thing in about libpq is that it knows server is OpenSSL. Bad thing
is that server may be old, so we need to support servers down to
OpenSSL 0.9.7. Which means TLSv1.0.
--
marko
