On Tue, Feb 04, 2020 at 09:24:41AM +0100, Johan Hovold wrote:

On Tue, Dec 10, 2019 at 12:37:31PM +0100, Johan Hovold wrote:

quoted

The driver was checking the number of endpoints of the first alternate
setting instead of the current one, something which could be used by a
malicious device (or USB descriptor fuzzer) to trigger a NULL-pointer
dereference.

Fixes: 1afca2b66aac ("Input: add Pegasus Notetaker tablet driver")
Cc: stable <redacted>     # 4.8
Cc: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Johan Hovold <johan@kernel.org>

Looks like the stable tag was removed when this one was applied, and
similar for patches 2, 4 and 7 of this series (commits 3111491fca4f,
a8eeb74df5a6, 6b32391ed675 upstream).

While the last three are mostly an issue for the syzbot fuzzer, we have
started backporting those as well.

This one (bcfcb7f9b480) is more clear cut as it can be used to trigger a
NULL-deref.

I only noticed because Sasha picked up one of the other patches in the
series which was never intended for stable.

Did I end up catching all of these properly?  I've had to expand my
search for some patches like this that do not explicitly have the cc:
stable mark on them as not all subsystems do this well (if at all.)

And there's also Sasha's work in digging up patches based on patterns of
fixes, which also is needed because of this "problem".

thanks,

greg k-h