On Thu, Jul 28, 2016 at 04:01:53PM -0400, Alan Stern wrote:
> On Thu, 28 Jul 2016, Alan Stern wrote:
>
> > On Thu, 28 Jul 2016, Greg KH wrote:
> >
> > > On Thu, Jul 28, 2016 at 12:23:01PM -0400, roswest wrote:
> > > >
> > > > Alan,
> > > >
> > > > Hi, I am an engineer at Cisco Systems, and this summer we tasked some
> > > > interns with performing USB fuzzing. One of the interns, Jake Lamberson,
> > > > was able to cause a kernel panic when emulating an HID keyboard because
> > > > the OHCI driver fails to reserve bandwidth for the device. Please see
> > > > the attachment for details.
> > > >
> > > > Thank you,
> > > > Rosie Hall
> > >
> > > >
> > > > Headline: Linux Kernel Panic Over USB with HID Keyboard
> > > > wMaxPacketSize
> > > > Platforms: Ubuntu
> > > > Versions: Linux Kernel 4.4.0-22-generic
> > > > CVSS Score: 4.7
> > > > CVSS Vector: AV:L/AC:M/Au:N/C:N/I:N/A:C
> > > > Filed Defects:
> > > > Related Defects:
> > > > CWE Tags:
> > > > Cycle:
> > > > Found by: Jake Lamberson
> > > >
> > > >
> > > > Linux Kernel panics when using an OHCI controller if a USB device
> > > > reports being
> > > > a generic HID keyboard and reports a wMaxPacketSize of over 4095. The
> > > > OHCI
> > > > controller driver fails to reserve bandwidth for the device, causing
> > > > the
> > > > keyboard handler to fail when attaching to the HID. Later, when the
> > > > device is
> > > > removed, the system crashes due to a null pointer dereference in a
> > > > linked list
> > > > of endpoint descriptors. The crash can be re-created using a Facedancer
> > > > and UMAP
> > > > software. Given an appropriately configured Facedancer and UMAP setup,
> > > > the crash
> > > > can be re-created with:
> > > > sudo board=facedancer21 python3 umap.py -P /dev/serial_device_here -f
> > > > 03:00:00:E:0046 -l LOG
>
> I forgot to mention that the original NULL-pointer dereference bug
> should already be fixed by commit c66f59ee5050 ("USB: OHCI: Don't mark
> EDs as ED_OPER if scheduling fails"). However I don't know if this
> commit has been back-ported to the kernel being tested.
I doubt it, it hasn't even hit the "normal" stable kernels yet, I'll go
do that now...
thanks,
greg k-h
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