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Date:   Mon, 01 Aug 2022 00:16:43 +0530
From:   Siddh Raman Pant <code@siddh.me>
To:     "Dipanjan Das" <mail.dipanjan.das@gmail.com>
Cc:     "David Howells" <dhowells@redhat.com>,
        "Greg KH" <gregkh@linuxfoundation.org>,
        "Christophe JAILLET" <christophe.jaillet@wanadoo.fr>,
        "Eric Dumazet" <edumazet@google.com>,
        "Fabio M. De Francesco" <fmdefrancesco@gmail.com>,
        "linux-security-modules" <linux-security-module@vger.kernel.org>,
        "linux-kernel-mentees" 
        <linux-kernel-mentees@lists.linuxfoundation.org>,
        "linux-kernel" <linux-kernel@vger.kernel.org>,
        "syzbot+c70d87ac1d001f29a058" 
        <syzbot+c70d87ac1d001f29a058@syzkaller.appspotmail.com>,
        "Marius Fleischer" <fleischermarius@googlemail.com>,
        "Priyanka Bose" <its.priyanka.bose@gmail.com>
Message-ID: <1825594fdb6.52eb2a02235647.5426665702277259900@siddh.me>
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References: <1822b768504.1d4e377e236061.5518350412857967240@siddh.me>
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Subject: Re: [PATCH] kernel/watch_queue: Make pipe NULL while clearing
 watch_queue
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On Sun, 31 Jul 2022 23:41:31 +0530  Dipanjan Das <mail.dipanjan.das@gmail.c=
om> wrote:
> On Wed, Jul 27, 2022 at 09:50:52PM +0530, Siddh Raman Pant wrote:
> > Thank you for explaining it!
> >=20
> > I will send a v3. Should I add a Suggested-by tag mentioning you?
>=20
> Sorry for jumping in.
>=20
> We have reported the same bug in kernel v5.10.131 [https://lore.kernel.or=
g/all/CANX2M5bHye2ZEEhEV6PUj1kYL2KdWYeJtgXw8KZRzwrNpLYz+A@mail.gmail.com]. =
We have been suggested to join this discussion so that we can have appropri=
ate meta-information injected in this patch=E2=80=99s commit message to mak=
e sure that it gets backported to v5.10.y.  Therefore, we would like to be =
in the loop so that we can offer help in the process, if needed.
>=20

As you are suggesting for backporting, I should CC the stable list, or mail
after it gets merged. You have reproduced it on v5.10, but the change seems=
 to
be introduced by c73be61cede5 ("pipe: Add general notification queue suppor=
t"),
which got in at v5.8. So should it be backported till v5.8 instead?

I actually looked this up on the internet / lore now for any other reports,=
 and
it seems this fixes a CVE (CVE-2022-1882).

The reporter of CVE seems to have linked his patch as a part of CVE report,=
 of
which he sent v2, but he seems to do it in a roundabout way, and also in a =
way
similar to what Hillf Danton had replied to my v2 patch, wherein he missed
353f7988dd84 ("watchqueue: make sure to serialize 'wqueue->defunct' properl=
y"),
so I guess I can propose my patch as a fix for the CVE.

Note: I have already sent the v3, so please suggest any new improvements et=
c.
(except replying to the conversation here) to the v3, which can be found he=
re:
https://lore.kernel.org/linux-kernel/20220728155121.12145-1-code@siddh.me/

Also, you may want to break text into multiples lines instead of one huge l=
ine.

Thanks,
Siddh