Re: [stable] [patch 29/37] dvb-core: Proper handling ULE SNDU length of 0

[Marcel Holtmann <marcel@holtmann.org>]

Hi Greg,

> > > ULE (Unidirectional Lightweight Encapsulation RFC 4326) decapsulation
> > > code has a bug that allows an attacker to send a malformed ULE packet
> > > with SNDU length of 0 and bring down the receiving machine. This patch
> > > fix the bug and has been tested on version 2.6.17.11. This bug is 100%
> > > reproducible and the modified source code (GPL) used to produce this bug
> > > will be posted on http://nrg.cs.usm.my/downloads.htm shortly.  The
> > > kernel will produce a dump during CRC32 checking on faulty ULE packet.
> > 
> > the upstream code changed for 2.6.18. It has a different way of
> > addressing this issue, but it also changes a lot of other stuff in the
> > whole code. However it might be worth looking at it, because the
> > upstream code might be still vulnerable.
> 
> So we should not take this patch for 2.6.17.y?  Do you have a different
> patch we should use instead?

I have no idea. I don't have any DVB hardware for testing at hand. The
patch looks sane and seems to fix this problem. However for upstream we
can't apply it and upstream might not be vulnerable, because of the
updated version. If upstream is not vulnerable, I would prefer we go
with the upstream version. Anyway, not my call to make.

Regards

Marcel


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