From: Anmol Karn <anmol.karan123@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: marcel@holtmann.org, johan.hedberg@gmail.com,
linux-kernel-mentees@lists.linuxfoundation.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
netdev@vger.kernel.org, linux-bluetooth@vger.kernel.org,
kuba@kernel.org, davem@davemloft.net,
syzbot+0bef568258653cff272f@syzkaller.appspotmail.com
Subject: Re: [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet()
Date: Tue, 15 Sep 2020 00:07:34 +0530 [thread overview]
Message-ID: <20200914183734.GA213347@Thinkpad> (raw)
In-Reply-To: <20200914154405.GC18329@kadam>
Hello Sir,
> > I have looked into the Bisected logs and the problem occurs from this commit:
> >
> > 941992d29447 ("ethernet: amd: use IS_ENABLED() instead of checking for built-in or module")
> >
>
> That's just the patch which made the code testable by syzbot. It didn't
> introduce the bug.
>
> >
> > Here is a diff of patch which i modified from last patch,
> >
> > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> > index 4b7fc430793c..6ce435064e0b 100644
> > --- a/net/bluetooth/hci_event.c
> > +++ b/net/bluetooth/hci_event.c
> > @@ -4936,6 +4936,12 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev,
> > return;
> > }
> >
> > + if (!hcon->amp_mgr) {
> > + hci_conn_del(hcon);
> > + hci_dev_unlock(hdev);
>
> I have no idea if calling hci_conn_del() is really the correct, thing.
> I don't know the code at all. Anyway, do some research and figure out
> for sure what the correct thing is.
I have created my patch on the basis of the already applied conditions handling
in this function, i.e whenever NULL dereference occurs, connection cleanup is
required hence, hci_conn_del() is used here. Will see if anything else could be
done.
>
> Also look for similar bugs in other places where hcon->amp_mgr is
> dereferenced. For example, amp_read_loc_assoc_final_data() seems to
> have a similar bug.
>
Sure sir will look into it.
> regards,
> dan carpenter
>
Thanks,
Anmol
next prev parent reply other threads:[~2020-09-14 18:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-10 4:34 [Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer dereference in hci_event_packet() Anmol Karn
2020-09-10 5:06 ` Eric Biggers
2020-09-10 6:02 ` Anmol Karn
2020-09-10 10:49 ` [Linux-kernel-mentees] " Dan Carpenter
2020-09-10 14:58 ` Anmol Karn
2020-09-12 9:10 ` Anmol Karn
2020-09-14 15:44 ` Dan Carpenter
2020-09-14 18:37 ` Anmol Karn [this message]
2020-09-29 17:32 ` Anmol Karn
2020-09-30 14:18 ` Anmol Karn
2020-10-01 7:06 ` Marcel Holtmann
2020-10-01 7:45 ` Anmol Karn
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