Re: 2.0.21 crashes with ISDN

Matthias Urlichs (smurf@smurf.noris.de)
Sat, 21 Sep 1996 13:13:03 +0100

In linux.dev.kernel, article <199609202025.WAA00771@wildsau.idv.uni-linz.ac.at>,
Herbert Rosmanith <herp@wildsau.idv.uni-linz.ac.at> writes:
>
> without this patch, a frame which is neither 1TR6 nor EDSS1 can
> a) crash the machine and if it does not b) will be misinterprated
> by the driver, which is IMO even worse than crashing (the error
> is more subtle then).
>
Problem (a) cannot be fixed by checking for non-EDSS1 frames.

_No_ incoming frame, however strange or broken it is, should ever be able
to crash the driver or the kernel. This is a requirement for compliance
with the EDSS1 standards (just like not sending broken frames is, but
that's the sender's problem).

We all know what happens when the receiver doesn't check for _everything_.
For a quick demonstration of this, consider Appletalk -- I can crash the
Mac AFP client quite easily by sending even perfectly legal replies which
just happen not to match the sender's expectations. :-(

-- 
Lysistrata had a good idea.

-- 
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