Re: UBSAN spat in valid xhci code in Linus's current tree (6.4+)

[Greg KH]

On Thu, Jun 29, 2023 at 11:58:43AM -0700, Kees Cook wrote:
> On Thu, Jun 29, 2023 at 05:36:51PM +0200, Greg KH wrote:
> > Boris just reported to me a UBSAN splat in the USB xhci driver in
> > Linus's tree that wasn't present in 6.4-final, and given that no USB
> > changes are merged yet there, I was confused.
> > 
> > Turns out, I think you all missed a "variable length" structure in the
> > xhci driver, which UBSAN is calling out a being an overrun, when really
> > it isn't (it's just written that way...)
> > 
> > The splat is:
> > 
> > UBSAN: array-index-out-of-bounds in drivers/usb/host/xhci-hub.c:231:31
> > index 1 is out of range for type '__le32 [1]'
> > CPU: 0 PID: 1556 Comm: kworker/0:2 Not tainted 6.4.0+ #7
> 
> This is fixed here, a couple weeks ago, but maybe it missed your tree:
> https://lore.kernel.org/lkml/20230614181307.gonna.256-kees@xxxxxxxxxx/
> 
> Would you prefer I carry it?

To confirm, that's already in my tree and will be going to Linus for
6.5-rc1.

thanks,

greg k-h