Re: [PATCH] USB: input: powermate: fix oops with malicious USB descriptors

[Dmitry Torokhov]

On Mon, Mar 14, 2016 at 09:15:48AM -0700, Greg Kroah-Hartman wrote:
> On Mon, Mar 14, 2016 at 10:12:53AM -0400, Josh Boyer wrote:
> > The powermate driver expects at least one valid USB endpoint in its
> > probe function.  If given malicious descriptors that specify 0 for
> > the number of endpoints, it will crash.  Validate the number of
> > endpoints on the interface before using them.
> > 
> > The full report for this issue can be found here:
> > http://seclists.org/bugtraq/2016/Mar/85
> > 
> > Reported-by: Ralf Spenneberg <ralf@xxxxxxxxxxxxxx>
> > Cc: stable <stable@xxxxxxxxxxxxxxx>
> > Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
> > ---
> >  drivers/input/misc/powermate.c | 3 +++
> >  1 file changed, 3 insertions(+)
> 
> I'll queue these up after 4.6-rc1 is out as the merge window is closed
> right now, but we might want to think about a better way to handle this
> type of thing in the USB core.  A way to keep from having to add checks

I do not see any reason in holding it until after rc1, applied.

> like this for every single driver, when the driver shouldn't even really
> have their probe function called unless their expected endpoints are
> going to be there.

I had a patch where driver could declare minimal amount of endpoints it
expects to find, but you mentioned we need something more flexible...

Thanks.

-- 
Dmitry