From: Jacob Champion <pchampion@vmware.com>
To: magnus@hagander.net <magnus@hagander.net>
Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>
Subject: Re: PROXY protocol support
Date: Wed, 3 Mar 2021 00:50:15 +0000
Message-ID: <b097096a23f0c9ee5b4c8d97fcc4aa64ec3fc97c.camel@vmware.com> (raw)
In-Reply-To: <CABUevExJ0ifpUEiX4uOREy0s2kHBrBrb=pXLEHhpMTR1vVR1XA@mail.gmail.com>
References: <CABUevExJ0ifpUEiX4uOREy0s2kHBrBrb=pXLEHhpMTR1vVR1XA@mail.gmail.com>
On Tue, 2021-03-02 at 18:43 +0100, Magnus Hagander wrote:
> PFA a simple patch that implements support for the PROXY protocol.
I'm not all the way through the patch yet, but this part jumped out at
me:
> + if (memcmp(proxyheader.sig, "\x0d\x0a\x0d\x0a\x00\x0d\x0a\x51\x55\x49\x54\x0a", sizeof(proxyheader.sig)) != 0)
> + {
> + /*
> + * Data is there but it wasn't a proxy header. Also fall through to
> + * normal processing
> + */
> + pq_endmsgread();
> + return STATUS_OK;
From my reading, the spec explicitly disallows this sort of fallback
behavior:
> The receiver MUST be configured to only receive the protocol described in this
> specification and MUST not try to guess whether the protocol header is present
> or not. This means that the protocol explicitly prevents port sharing between
> public and private access.
You might say, "if we already trust the proxy server, why should we
care?" but I think the point is that you want to catch
misconfigurations where the middlebox is forwarding bare TCP without
adding a PROXY header of its own, which will "work" for innocent
clients but in reality is a ticking timebomb. If you've decided to
trust an intermediary to use PROXY connections, then you must _only_
accept PROXY connections from that intermediary. Does that seem like a
reasonable interpretation?
--Jacob
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To: pgsql-hackers@postgresql.org
Cc: pchampion@vmware.com, magnus@hagander.net, pgsql-hackers@lists.postgresql.org
Subject: Re: PROXY protocol support
In-Reply-To: <b097096a23f0c9ee5b4c8d97fcc4aa64ec3fc97c.camel@vmware.com>
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