netdev - Re: sunrpc port allocation and IANA reserved list

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4AF9B2CF.6050305@nortel.com>
Date:	Tue, 10 Nov 2009 12:37:03 -0600
From:	"Chris Friesen" <cfriesen@...tel.com>
To:	Ben Hutchings <bhutchings@...arflare.com>
CC:	netdev@...r.kernel.org, Linux kernel <linux-kernel@...r.kernel.org>
Subject: Re: sunrpc port allocation and IANA reserved list

On 11/10/2009 11:53 AM, Ben Hutchings wrote:
> On Tue, 2009-11-10 at 11:43 -0600, Chris Friesen wrote:

>> Given that a userspace application can be stopped and restarted at any
>> time, and a sunrpc registration can happen at any time, what is the
>> expected mechanism to prevent the kernel from allocating a port for use
>> by sunrpc that reserved or well-known?
>>
>> Apparently Redhat and Debian have distro-specific ways of dealing with
>> this, but is there a standard solution?  Should there be?
>>
>> The current setup seems suboptimal.
> 
> I believe both RH and Debian are using the same implementation:
> <http://cyberelk.net/tim/software/portreserve/>.

That helps with the startup case, but still leaves a possible hole if an
app using a fixed port number is restarted at runtime.  During the
window where nobody is bound to the port, the kernel could randomly
assign it to someone else.

Chris
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html