Re: [PATCH 1/7] Input: pegasus_notetaker: fix endpoint sanity check

From: Johan Hovold <johan@kernel.org>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Johan Hovold <johan@kernel.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, linux-input@vger.kernel.org,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Martin Kepplinger <martink@posteo.de>
Subject: Re: [PATCH 1/7] Input: pegasus_notetaker: fix endpoint sanity check
Date: Wed, 5 Feb 2020 13:54:26 +0100	[thread overview]
Message-ID: <20200205125426.GT26725@localhost> (raw)
In-Reply-To: <20200204192434.GH184237@dtor-ws>

On Tue, Feb 04, 2020 at 11:24:34AM -0800, Dmitry Torokhov wrote:
> On Tue, Feb 04, 2020 at 11:14:35AM +0100, Johan Hovold wrote:
> > On Tue, Feb 04, 2020 at 10:02:32AM +0000, Greg Kroah-Hartman wrote:
> > > 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:
> > > > > 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 <stable@vger.kernel.org>     # 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.)
> > 
> > No, sorry, should have been more clear on that point; these four were
> > never picked up for stable it seems.
> > 
> > I was a bit surprised to see the stable-tags be removed from the
> > original submissions here, even if I know the net-maintainers do this
> > routinely, and any maintainer can of course override a submitters
> > judgement.
> 
> Sorry, dropping stable tags was not intentional. I was trying to improve
> my tooling and drop the CC noise from the changelogs, but my script got
> too eager and removed "Cc: stable" as well. I believe my tool should be
> fixed now and it should not happen again.

Ah, ok, thanks for confirming.

Johan