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From:   Alexander Potapenko <glider@google.com>
Date:   Tue, 30 Jul 2019 16:28:31 +0200
Message-ID: <CAG_fn=XOZVRkG+RLRsfn2Y4JNz+ovyjkA=Jf9TK5ttunmuNvmA@mail.gmail.com>
Subject: Re: KMSAN: kernel-usb-infoleak in pcan_usb_pro_send_req
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Alan Stern <stern@rowland.harvard.edu>,
        syzbot <syzbot+513e4d0985298538bf9b@syzkaller.appspotmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
        Kernel development list <linux-kernel@vger.kernel.org>,
        USB list <linux-usb@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
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On Tue, Jul 30, 2019 at 4:22 PM 'Andrey Konovalov' via syzkaller-bugs
<syzkaller-bugs@googlegroups.com> wrote:
>
> On Tue, Jul 30, 2019 at 4:20 PM Andrey Konovalov <andreyknvl@google.com> =
wrote:
> >
> > On Tue, Jul 30, 2019 at 4:17 PM Alan Stern <stern@rowland.harvard.edu> =
wrote:
> > >
> > > On Tue, 30 Jul 2019, syzbot wrote:
> > >
> > > > Hello,
> > > >
> > > > syzbot found the following crash on:
> > > >
> > > > HEAD commit:    41550654 [UPSTREAM] KVM: x86: degrade WARN to pr_wa=
rn_rate..
> > > > git tree:       kmsan
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=3D13e9518=
3a00000
> > > > kernel config:  https://syzkaller.appspot.com/x/.config?x=3D40511ad=
0c5945201
> > > > dashboard link: https://syzkaller.appspot.com/bug?extid=3D513e4d098=
5298538bf9b
> > > > compiler:       clang version 9.0.0 (/home/glider/llvm/clang
> > > > 80fee25776c2fb61e74c1ecb1a523375c2500b69)
> > > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D17eaf=
a1ba00000
> > > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D17b8798=
3a00000
> > > >
> > > > IMPORTANT: if you fix the bug, please add the following tag to the =
commit:
> > > > Reported-by: syzbot+513e4d0985298538bf9b@syzkaller.appspotmail.com
> > > >
> > > > usb 1-1: config 0 has no interface number 0
> > > > usb 1-1: New USB device found, idVendor=3D0c72, idProduct=3D0014,
> > > > bcdDevice=3D8b.53
> > > > usb 1-1: New USB device strings: Mfr=3D0, Product=3D0, SerialNumber=
=3D0
> > > > usb 1-1: config 0 descriptor??
> > > > peak_usb 1-1:0.146: PEAK-System PCAN-USB X6 v0 fw v0.0.0 (2 channel=
s)
> > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > > > BUG: KMSAN: kernel-usb-infoleak in usb_submit_urb+0x7ef/0x1f50
> > > > drivers/usb/core/urb.c:405
> > >
> > > What does "kernel-usb-infoleak" mean?
> >
> > That means that the kernel put some uninitialized data into a request
> > that was sent to a USB device.
>
> Here's a better report for this bug:
Yes, for some reason syzkaller lost half of the original report when
reproducing the bug.
> https://syzkaller.appspot.com/text?tag=3DCrashReport&x=3D11dae8ec600000
>
> This is a real bug, I was able to reproduce it with a hardware
> reproducer and leak some kernel pointers AFAIR.

> >
> > >
> > > Alan Stern
> > >
>
> --
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--=20
Alexander Potapenko
Software Engineer

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