Re: [PATCH v2 RESEND] media: firewire: firedtv-avc: fix a buffer overflow in avc_ca_pmt()

From: Michael Ellerman <mpe@ellerman.id.au>
To: Linus Torvalds <torvalds@linuxfoundation.org>,
	Salvatore Bonaccorso <carnil@debian.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>,
	Stefan Richter <stefanr@s5r6.in-berlin.de>,
	Luo Likang <luolikang@nsfocus.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Linux Media Mailing List <linux-media@vger.kernel.org>,
	linux1394-devel@lists.sourceforge.net,
	Yang Yanchao <yangyanchao6@huawei.com>,
	Security Officers <security@kernel.org>
Subject: Re: [PATCH v2 RESEND] media: firewire: firedtv-avc: fix a buffer overflow in avc_ca_pmt()
Date: Mon, 13 Sep 2021 12:50:19 +1000	[thread overview]
Message-ID: <87pmtdkx3o.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <CAHk-=wjOW3Fx8td1Snezd1_9sf8q7KuQx8TyQNR0ypS2rVBHtg@mail.gmail.com>

Linus Torvalds <torvalds@linuxfoundation.org> writes:
> On Sun, Sep 12, 2021 at 6:14 AM Salvatore Bonaccorso <carnil@debian.org> wrote:
>>
>> On Wed, Sep 01, 2021 at 01:40:26PM +0300, Dan Carpenter wrote:
>> > On Mon, Aug 16, 2021 at 10:27:22AM +0300, Dan Carpenter wrote:
>> > > The bounds checking in avc_ca_pmt() is not strict enough.  It should
>> > > be checking "read_pos + 4" because it's reading 5 bytes.  If the
>> > > "es_info_length" is non-zero then it reads a 6th byte so there needs to
>> > > be an additional check for that.
>> > >
>> > > I also added checks for the "write_pos".  I don't think these are
>> > > required because "read_pos" and "write_pos" are tied together so
>> > > checking one ought to be enough.
>
> They may be in sync at a fixed offset, but the buffer length of the
> read ("int length") is not in sync with the buffer length for the
> write ("sizeof(c->operand)").
>
> So I do think the write pos limit checking is actually necessary and needed.
>
>> > > RESEND: this patch got lost somehow.
>> >
>> > What the heck?  Someone on patchwork just marked this patch as obsolete
>> > again!!!
>
> Can we please make sure patchwork has some logging so that that kind
> of thing shows _who_ did this?

It's not easily visible in the web UI, but patchwork does log that sort
of info.

The v2 RESEND is:

 https://patchwork.linuxtv.org/project/linux-media/patch/20210816072721.GA10534@kili/

In the top right is the patch id (76352), you can then get the list of
events for that patch at:

  https://patchwork.linuxtv.org/api/events/?patch=76352

Which shows that hverkuil changed it to obsolete on 2021-09-01T10:16:43.

Presumably because they picked up the non-resend version, which was
marked as under-review around the same time:

  https://patchwork.linuxtv.org/api/events/?patch=74849

And then also visible on the above page, it was marked as accepted by
mchehab on 2021-09-03T13:06:16.

But I don't see the patch in linux-next, or in linux-media.git, so I'm
not sure where it's been accepted to?

cheers