[pkg-ntp-maintainers] Bug#562065: Bug#562065: ntp server didn't support mssntp

[Kurt Roeckx]

On Tue, Dec 22, 2009 at 09:53:00PM +0300, Matthieu Patou wrote:
> On 22/12/2009 20:53, Kurt Roeckx wrote:
> >On Tue, Dec 22, 2009 at 02:33:54PM +0300, Matthieu Patou wrote:
> >>Subject: ntp server didn't support mssntp
> >>Package: ntp
> >>Version: 4.2.4p4+dfsg-8lenny3
> >>Severity: wishlist
> >>Tags: patch
> >
> >You tagged it patch, but you don't provide any patch?
> No good excuse, but I was missing a category saying that the patch
> is already in the upstream source.
> >
> >>Current version of ntp  in debian do not support MS SNTP extension.
> >[...]
> >>Version 4.2.6 of ntp (released on 12/12/09)  now include patches for
> >>allowing this extension but must be complied specifically with the
> >>option --enable-ntp-signd to effectively  build this extension.
> >
> >So this is a wishlist bug asking for a new upstream version
> >with tht configure option?  Any idea why this isn't on by default?
> See the talk in this bug
> https://support.ntp.org/bugs/show_bug.cgi?id=1405. Basically I'll
> say that Ph. D. Mills is a bit overcautious as he don't want ntp to
> be blamed for an admin that activated this option and get flooded.
> It's in fact the same problem as refclock that has to be explicitly
> activated during configure if you want to have it (as debian does).
> 
> 
> I am not of course willing to make debian user run a risk when using
> the new version of ntp with this extension. So it must be noted that
> even if the extension is built in the ntp server it must be opted in
> to start to work. This piece of code protects the emission to the
> signed socket:
> 
>   if (flags & RES_MSSNTP) {
>     send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt);
>     return;
>   }
> 
> If no restrict is defined or if didn't match the user ip address
> then the send_via_ntp_signd is not called.
> It's obvious that any publicly available server shoudn't have this
> activated.

As I understand David L. Mills, it always opens a TCP socket
independent of the configuration file, and that that can be
used to DoS the server.  If that's not the case I see no
problem with enabling this by default.


Kurt