Re: primary_conninfo missing from pg_stat_wal_receiver

From: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>
To: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Cc: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Tatsuo Ishii <ishii(at)postgresql(dot)org>, Vik Fearing <vik(at)2ndquadrant(dot)fr>, PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: primary_conninfo missing from pg_stat_wal_receiver
Date: 2016-06-29 18:17:50
Message-ID: 20160629181750.GA124315@alvherre.pgsql
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Fujii Masao wrote:
> On Thu, Jun 30, 2016 at 2:50 AM, Alvaro Herrera
> <alvherre(at)2ndquadrant(dot)com> wrote:
> > Fujii Masao wrote:
> >> On Wed, Jun 29, 2016 at 12:23 PM, Alvaro Herrera
> >> <alvherre(at)2ndquadrant(dot)com> wrote:
> >> > Michael Paquier wrote:
> >> >> On Wed, Jun 29, 2016 at 6:42 AM, Alvaro Herrera
> >> >> <alvherre(at)2ndquadrant(dot)com> wrote:
> >> >
> >> >> > I have already edited the patch following some of these ideas. Will
> >> >> > post a new version later.
> >> >>
> >> >> Cool, thanks.
> >> >
> >> > Here it is. I found it was annoying to maintain the function return
> >> > tupdesc in two places (pg_proc.h and the function code itself), so I
> >> > changed that too.
> >>
> >> ISTM that pg_stat_wal_receiver can return the security-sensitive fields
> >> if it's viewed before walreceiver overwrites the conninfo in the shared memory
> >> with the obfuscated one.
> >
> > Hmm, ouch. Maybe we can set a flag once the conninfo has been
> > obfuscated, and put the function to sleep until the flag is set.
> Or what about making walreceiver instead of startup process read
> primary_conninfo from the file?

Yeah, that sounds smart. I'm not sure it's a good fit for 9.6; what I
propose can be implemented in 10 lines, attached (wherein I also adopted
Michael's suggestion to get rid of the extra whitespace)

I propose to push this patch, closing the open item, and you can rework
on top -- I suppose you would completely remove the original conninfo
from shared memory and instead only copy the obfuscated version there
(and probably also remove the ready_to_display flag). I think we'd need
to see the patch before deciding whether we want it in 9.6 or not,
keeping in mind that having the conninfo in shared memory is a
pre-existing problem, unrelated to the pgstats view new in 9.6.

Álvaro Herrera
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Attachment Content-Type Size
wal-receiver-conninfo-v5.patch text/x-diff 12.0 KB

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