Date: Tue, 1 Mar 2011 17:59:05 -0500 (EST) From: Rick Macklem <rmacklem@uoguelph.ca> To: Brooks Davis <brooks@freebsd.org> Cc: net@freebsd.org Subject: Re: any is vfs.nfsrv.nfs_privport=0 by default Message-ID: <297419299.601659.1299020345042.JavaMail.root@erie.cs.uoguelph.ca> In-Reply-To: <20110228154831.GC41129@lor.one-eyed-alien.net>
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> vfs.nfsrv.nfs_privport controls wither or not NFS enforces the
> traditional RPC semantics that require that requests come from
> "privileged" ports. By default this check is disabled. Hardening
> guides typically suggest this be enabled, usually via the rc.conf knob
> nfs_reserved_port_only=YES.
>
> I'm trying to find a good reason why the default is the way it is.
> Digging around in the source tree it appears that the rc.conf setting
> has been that way since either /etc/rc.conf or /etc/defaults/rc.conf
> has
> been in the tree.
>
> I do not consider the fact that the security provided is weak at best
> to
> be a good reason to disable it. I suspect support for PC-NFS or
> something like that may be the reason, but if that's the case it
> really
> doesn't make any sense.
>
Two comments:
1 - RFC3530 (NFSv4) specifically states that reserved port #s cannot be
required.
--> If you change the defaults, it will be different for NFSv4 than
NFSv2,3. Not incorrect, but a little weird.
2 - It was probably disabled by default so that clients wouldn't run out
of reserved ports when doing lotsa mounts.
But, I don't care what the default is for NFSv2,3, rick
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