[zeromq-dev] Vulnerability of devices to incoming messages

[Matt Weinstein]

Here's one argument against this:

If you forward a malformed stream to an XREP you have a design flaw,  
and you should fix it.  Proper input checking should be done.

Making the traffic disappear without any indication will make error  
detection and correction much more difficult, especially when dealing  
with these exotic socket types.

If you do decide to implement the non-strict form, it is still an  
error IMO and should return an error indication, even if it does not  
cause massive destruction within the environment.

Thanks,

Best,
Matt


On Aug 11, 2010, at 2:23 PM, MinRK wrote:

> That does indeed fix the vulnerability in my code, thanks!
>
> Is it better for zmq in general, though, for xrep.send('msg') to  
> silently fail, rather than raise? It's good for me, but I can  
> imagine others having objections.
>
> I suppose this does better match the behavior of having an unmatched  
> identity prefix on a valid message on an xrep, which just vanishes  
> into the aether, right?
>
> -MinRK
>
> On Wed, Aug 11, 2010 at 04:03, Pieter Hintjens <ph at imatix.com> wrote:
> Hi Benjamin,
>
> Here's a patch for xrep.cpp that silently drops the message if it's
> malformed.  This will make the standard devices robust against the
> vulnerability you explained.
>
> I've tested it and it works for your test case.  Could you confirm it
> works, then I'll commit the change to master.
>
> http://gist.github.com/518810
>
> -Pieter
>
> On Tue, Aug 10, 2010 at 7:30 PM, MinRK <benjaminrk at gmail.com> wrote:
> > It is posted here:
> > http://github.com/zeromq/zeromq2/issues/issue/46
> > with accompanying gist for reproducing the issue.
> >
> > -MinRK
> > On Tue, Aug 10, 2010 at 01:25, Pieter Hintjens <ph at imatix.com>  
> wrote:
> >>
> >> Benjamin,
> >>
> >> Could you provide a minimal test case that reproduces the  
> problem, and
> >> perhaps file an issue on the github tracker, thanks.
> >>
> >> -Pieter
> >>
> >> On Tue, Aug 10, 2010 at 8:34 AM, MinRK <benjaminrk at gmail.com>  
> wrote:
> >> > Hello,
> >> > I'm using ZMQ devices for parallel computing in IPython.  One  
> of our
> >> > devices
> >> > is a Queue with XREQ on one side and XREP on the other. This  
> model, like
> >> > any
> >> > device where one socket requires an IDENT prefix (XREP), and  
> the other
> >> > does
> >> > not prepend a message (anything other than XREP), is vulnerable  
> to
> >> > invalid
> >> > messages. If the socket that is not XREP receives a single  
> message, that
> >> > will be relayed to the XREP as a message with routing IDENTITY  
> but no
> >> > content. This fails an assertion, and triggers SIGABRT,  
> bringing down
> >> > the
> >> > entire process.
> >> > It is a security concern for us that _incoming_ messages have the
> >> > ability to
> >> > crash the device process. Are there any standard models or  
> plans for ZMQ
> >> > devices that can survive invalid messages like this?
> >> > -MinRK
> >> > _______________________________________________
> >> > zeromq-dev mailing list
> >> > zeromq-dev at lists.zeromq.org
> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev
> >> >
> >> >
> >> _______________________________________________
> >> zeromq-dev mailing list
> >> zeromq-dev at lists.zeromq.org
> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
> >
> >
> > _______________________________________________
> > zeromq-dev mailing list
> > zeromq-dev at lists.zeromq.org
> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev
> >
> >
> _______________________________________________
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
> _______________________________________________
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.zeromq.org/pipermail/zeromq-dev/attachments/20100811/86b7aeb4/attachment.htm>