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Re: Spoofing as the postmaster

From: Magnus Hagander <magnus(at)hagander(dot)net>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Andrew Dunstan <andrew(at)dunslane(dot)net>, Andrew Sullivan <ajs(at)crankycanuck(dot)ca>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Spoofing as the postmaster
Date: 2007-12-27 21:50:22
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers
Tom Lane wrote:
> Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
>> I have no problem with that. But it does seem to me that we are going 
>> about this all wrong. The OP proposed a "solution" which was intended to 
>> ensure at the server end that an untrusted user could not spoof the 
>> postmaster if the postmaster were not running. Putting the onus of this 
>> on clients seems wrong. I don't have any experience with SELinux, but my 
>> impression is that it can be used to control who or what can open files, 
>> sockets etc. On Linux at least this strikes me as a more productive 
>> approach to the original problem, as it would put the solution in the 
>> SA's hands. Maybe other Unices and Windows have similar capabilities?
> Most Linux distros don't have SELinux, AFAIK, so this is probably not a
> very useful suggestion.  Not that I have a problem with Red-Hat-specific
> solutions ;-) ... but since one of the arguments being made against
> move-the-socket is that it introduces a lot of platform-specific
> assumptions, we have to apply that same criterion to alternative
> answers.
> As far as ensuring security from the server end, what about extending
> the pg_hba.conf options to require that the server has both checked
> a client certificate and presented its own certificate?  (I'm not sure
> whether OpenSSL provides a way to determine that, though.)

A server has *always* presented its certificate. SSL doesn't work
otherwise. What we can't know is if the client *verified* the
certificate. But there's no way to control that from server-side anyway...

And we do request the client certificate if the server is provided with
a root certificate store to verify it against... I'm not sure we gain a
lot by adding a second option to do the same thing (which still will
need said root certificate store to work)


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