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From:   Andrey Konovalov <andreyknvl@google.com>
Date:   Tue, 30 Jul 2019 16:22:07 +0200
Message-ID: <CAAeHK+z50rsvQypF5AivYJh0wQ04XAueC=Ms2cPt3+QuN1+KGg@mail.gmail.com>
Subject: Re: KMSAN: kernel-usb-infoleak in pcan_usb_pro_send_req
To:     Alan Stern <stern@rowland.harvard.edu>
Cc:     syzbot <syzbot+513e4d0985298538bf9b@syzkaller.appspotmail.com>,
        Alexander Potapenko <glider@google.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 4:20 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_warn_rate..
> > > git tree:       kmsan
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=13e95183a00000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=40511ad0c5945201
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=513e4d0985298538bf9b
> > > compiler:       clang version 9.0.0 (/home/glider/llvm/clang
> > > 80fee25776c2fb61e74c1ecb1a523375c2500b69)
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17eafa1ba00000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17b87983a00000
> > >
> > > 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=0c72, idProduct=0014,
> > > bcdDevice=8b.53
> > > usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
> > > usb 1-1: config 0 descriptor??
> > > peak_usb 1-1:0.146: PEAK-System PCAN-USB X6 v0 fw v0.0.0 (2 channels)
> > > ==================================================================
> > > 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:

https://syzkaller.appspot.com/text?tag=CrashReport&x=11dae8ec600000

This is a real bug, I was able to reproduce it with a hardware
reproducer and leak some kernel pointers AFAIR.

>
> >
> > Alan Stern
> >