Date: Thu, 23 Apr 1998 03:54:21 +0800 From: Peter Wemm <peter@netplex.com.au> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com>, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG, cvs-usrsbin@FreeBSD.ORG, soren@dt.dk Subject: Re: cvs commit: src/usr.sbin/syslogd syslogd.c Message-ID: <199804221954.DAA12177@spinner.netplex.com.au> In-Reply-To: Your message of "Wed, 22 Apr 1998 20:47:34 %2B0200." <4371.893270854@critter.freebsd.dk>
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Poul-Henning Kamp wrote:
> In message <199804221810.LAA07748@GndRsh.aac.dev.com>, "Rodney W. Grimes" wri
tes:
> >>
> >> Hmmmm,
> >>
> >> Now, I'm not too sure what people use SecureMode for, but it doesn't
> >> make sense to expect one host to accept remote logging from other
> >> hosts that don't, at least in my book...
> >
> >Your book may not involve a large AS of systems that remotely syslog to
> >a central syslog server. All ``syslog clients'' run in syslogd -s mode,
> >the ``syslog server'' runs in normal syslogd mode, but has ipfw setup
> >such that it only accepts syslog packets from a trusted list of clients.
>
> Well, for the ipfw to work, wouldn't the socket need to be bound to
> a well-known-port then ? That was the fact that made me conclude that
> you couldn't do the above scenario in the first place.
If you run in -s mode, syslogd doesn't bind(), so it *cannot* receive
packets, period. -s mode is "do not listen" to the network, it's not
supposed to stop that instance of syslogd from sending.
> I would think that all securemode should do would be to not include the
> fd in what select is watching, but the code before this change also
> diked out the bind, so you wouldn't know what port you would be sending
> syslog messages from, making ipfw unable to decide if the message came
> from syslogd or some random user...
Securemode stops the bind() and the select(). ipfw is irrelevant in
-s mode since it doesn't receive data. The socket is only used for
sendto(). It's created and kept around so that syslogd can't ever get
stuck trying to send a critical log message over the network but fail
because all fd's are in use.
You use ipfw or syslogd's internal masks (see -a flag) without the -s flag
in order to safely get logs from other syslogds over the network.
-s was working exactly as indented (and documented) before (although the
code was messy, I'll grant you that. :-)
>From the FM:
-s Operate in secure mode. Do not listen for log message from re-
mote machines.
Nowhere does it imply that -s make syslogd fail to process the @loghost
syslog.conf directives.
On the client machines, you use -s and divert important logs to the server.
On the server machine(s), you use -a and/or ipfw to limit where you'll
accept packets from.
Argueably, syslogd should not listen by default and should require a switch
to activate network listening, but that breaks POLA when people do a 'make
world' or upgrade. (this is the same reason why named still has a path to
/etc/named.boot compiled into it, and yet we have shipped /etc/namedb/
named.boot for ages... People don't often update their /etc stuff.)
> --
> Poul-Henning Kamp FreeBSD coreteam member
> phk@FreeBSD.ORG "Real hackers run -current on their laptop."
> "Drink MONO-tonic, it goes down but it will NEVER come back up!"
>
Cheers,
-Peter
--
Peter Wemm <peter@netplex.com.au> Netplex Consulting
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