Re: [PATCH v20] GSSAPI encryption support

From: Robbie Harwood <rharwood(at)redhat(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Stephen Frost <sfrost(at)snowman(dot)net>
Cc: Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, David Steele <david(at)pgmasters(dot)net>, Joe Conway <mail(at)joeconway(dot)com>, Magnus Hagander <magnus(at)hagander(dot)net>, Michael Paquier <michael(at)paquier(dot)xyz>, Nico Williams <nico(at)cryptonector(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [PATCH v20] GSSAPI encryption support
Date: 2019-04-04 17:14:32
Message-ID: jlgv9ztr8uf.fsf@redhat.com
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Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> Stephen Frost <sfrost(at)snowman(dot)net> writes:
>> * Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
>>> Well, if the caller thinks what is being passed back is an int,
>>> it will do a 32-to-64-bit widening, which is almost certainly
>>> going to result in a corrupted pointer.
>
>> Oh, good point. Interesting that it still works then.
>
> There must be something about the x86_64 ABI that allows this to
> accidentally work -- maybe integers are presumed to be sign-extended
> to 64 bits by callee not caller? I added some logging and verified
> that pgstat.c is seeing the correct string value, so it's working
> somehow.
>
>> I've got a fix for the missing prototypes, I hadn't noticed the issue
>> previously due to always building with SSL enabled as well.
>
> Yeah, I'd just come to the conclusion that it's because I didn't
> include --with-openssl, and libpq-be.h's #ifdef nest doesn't expect
> that.
>
> BTW, the kerberos test suite takes nearly 4 minutes for me, is
> it supposed to be so slow?

My guess is entropy problems as well. If available, configuring
/dev/urandom passthrough from the host is a generally helpful thing to
do.

My (Fedora, Centos/RHEL 7+) krb5 builds use getrandom() for entropy, so
they shouldn't be slow; I believe Debian also has started doing so
recently as well. I don't know what other distros/OSs do for this.

Thanks,
--Robbie

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