Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <000000000000d9a391059713dc1f@google.com> <20191111160950.GA870254@kroah.com>
 <1574248737.14298.33.camel@suse.com>
In-Reply-To: <1574248737.14298.33.camel@suse.com>
From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Wed, 20 Nov 2019 12:24:50 +0100
Message-ID: <CACT4Y+ZQK4knKqPxESGspc1gBNA6rMTPW=28j3W-oexcyRRepw@mail.gmail.com>
Subject: Re: BUG: bad host security descriptor; not enough data (4 vs 5 left)
To:     Oliver Neukum <oneukum@suse.com>
Cc:     Greg KH <greg@kroah.com>,
        syzbot <syzbot+d934a9036346e0215d8f@syzkaller.appspotmail.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        USB list <linux-usb@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Nov 20, 2019 at 12:19 PM Oliver Neukum <oneukum@suse.com> wrote:
>
> Am Montag, den 11.11.2019, 17:09 +0100 schrieb Greg KH:
> > On Mon, Nov 11, 2019 at 07:34:08AM -0800, syzbot wrote:
> > > Hello,
> > >
> > > syzbot found the following crash on:
> > >
> > > HEAD commit:    3183c037 usb: gadget: add raw-gadget interface
> > > git tree:       https://github.com/google/kasan.git usb-fuzzer
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=3D12525dc6e=
00000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=3D79de80330=
003b5f7
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=3Dd934a903634=
6e0215d8f
> > > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D14ac740=
6e00000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D13eea39ae=
00000
> > >
> > > IMPORTANT: if you fix the bug, please add the following tag to the co=
mmit:
> > > Reported-by: syzbot+d934a9036346e0215d8f@syzkaller.appspotmail.com
> > >
> > > usb 1-1: config 0 interface 0 altsetting 0 has 3 endpoint descriptors=
,
> > > different from the interface descriptor's value: 4
> > > usb 1-1: New USB device found, idVendor=3D13dc, idProduct=3D5611,
> > > bcdDevice=3D2f.15
> > > usb 1-1: New USB device strings: Mfr=3D0, Product=3D0, SerialNumber=
=3D0
> > > usb 1-1: config 0 descriptor??
> > > hwa-hc 1-1:0.0: Wire Adapter v106.52 newer than groked v1.0
> > > hwa-hc 1-1:0.0: FIXME: USB_MAXCHILDREN too low for WUSB adapter (194 =
ports)
> > > usb 1-1: BUG: bad host security descriptor; not enough data (4 vs 5 l=
eft)
> > > usb 1-1: supported encryption types: =EF=BF=BDS =D0=81=EF=BF=BD=EF=BF=
=BD=EF=BF=BD|c =D0=81=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BDc =D0=81=EF=BF=BD=
=EF=BF=BD=EF=BF=BD
> > > usb 1-1: E: host doesn't support CCM-1 crypto
> > > hwa-hc 1-1:0.0: Wireless USB HWA host controller
> > > hwa-hc 1-1:0.0: new USB bus registered, assigned bus number 11
> >
> > wusb code, hah.  It's about to be deleted from the kernel because no on=
e
> > uses it and there is no hardware out there.  I wouldn't spend a ton of
> > time fuzzing it.
> >
> > One more good reason to just delete it soon...
>
> Unfortunately that is not an option for the stable trees. Before I try
> something quick and dirty here, I have a question for the testing team.
>
> What exactly crashed? There is nothing in the logs? Did you undergo
> an absolute freeze of the machine? Or do you tested for the word "BUG"
> in the logs?

Hi Oliver,

Yes, it's the "BUG:" on the console that's detected as kernel bug
(what's being produced by BUG_ON).

There are only 2 special bug types in syzkaller that are detected
based not on kernel output matching:
"lost connection to test machine":
https://syzkaller.appspot.com/bug?id=3Db97ec15bfe317ac1ddccb41f2a913d4f7a31=
c6d7
and "no output from test machine":
https://syzkaller.appspot.com/bug?id=3D0b210638616bb68109e9642158d4c0072770=
ae1c
(hopefully self-explanatory from the title).

The rest are based on output matching and what's matched is pretty
much the bug title/email subject.