Re: usb/serial/visor: slab-out-of-bounds in palm_os_3_probe

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Oct 03, 2017 at 11:29:40AM +0200, Johan Hovold wrote:
> On Fri, Sep 29, 2017 at 10:37:55AM +0200, Greg Kroah-Hartman wrote:
> > On Thu, Sep 28, 2017 at 07:57:46PM +0200, Andrey Konovalov wrote:
> > > Hi!
> > > 
> > > I've got the following report while fuzzing the kernel with syzkaller.
> > > 
> > > On commit dc972a67cc54585bd83ad811c4e9b6ab3dcd427e (4.14-rc2+).
> > > 
> > > There's no check on the connection_info->num_ports value when
> > > iterating over ports.
> > > 
> > > usb 1-1: Handspring Visor / Palm OS: port 162, is for unknown use
> > > usb 1-1: Handspring Visor / Palm OS: port 81, is for unknown use
> > > ==================================================================
> > > BUG: KASAN: slab-out-of-bounds in palm_os_3_probe+0x4e4/0x570
> > > Read of size 1 at addr ffff8800686daa26 by task kworker/0:1/24
> 
> Thanks for the report, Andrey.
> 
> > Ah, nice catch, this bug is _old_, sorry about that.
> > 
> > The patch below should resolve this.  It looks bigger than it really is,
> > as I'm just moving the error checking higher up in the function, and
> > loosing an indentation for when there is invalid data.
> > 
> > Can you let me know if this solves the issue?
> 
> And thanks for fixing this up, Greg. Will you send a proper patch that I
> can apply?

Yes, let me redo it based on your comments, and will send it out
"correctly" in a few days.

thanks for the review,

greg k-h