Re: Protocol problem with GSSAPI encryption? - Mailing list pgsql-hackers

From Andrew Gierth
Subject Re: Protocol problem with GSSAPI encryption?
Date
Msg-id 87eewyc1np.fsf@news-spur.riddles.org.uk
Whole thread Raw
In response to Re: Protocol problem with GSSAPI encryption?  (Bruce Momjian <bruce@momjian.us>)
Responses Re: Protocol problem with GSSAPI encryption?  (Bruce Momjian <bruce@momjian.us>)
List pgsql-hackers
>>>>> "Bruce" == Bruce Momjian <bruce@momjian.us> writes:

 >> This came up recently on IRC, not sure if the report there was
 >> passed on at all.
 >> 
 >> ProcessStartupPacket assumes that there will be only one negotiation
 >> request for an encrypted connection, but libpq is capable of issuing
 >> two: it will ask for GSS encryption first, if it looks like it will
 >> be able to do GSSAPI, and if the server refuses that it will ask (on
 >> the same connection) for SSL.

 Bruce> Are you saying that there is an additional round-trip for
 Bruce> starting all SSL connections because we now support GSSAPI, or
 Bruce> this only happens if libpq asks for GSSAPI?

The problem only occurs if libpq thinks it might be able to do GSSAPI,
but the server does not. Without the patch I proposed or something like
it, this case fails to connect at all; with it, there will be an extra
round-trip. Explicitly disabling GSSAPI encryption in the connection
string or environment avoids the issue.

The exact condition for libpq seems to be a successful call to
gss_acquire_cred, but I'm not familiar with GSS in general.

-- 
Andrew (irc:RhodiumToad)



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