On Mon, Jul 12, 2021 at 05:50:41PM +0200, Johan Hovold wrote:
> On Mon, Jul 12, 2021 at 05:29:20PM +0200, Johan Hovold wrote:
> > On Mon, Jul 12, 2021 at 10:00:04AM -0400, Alan Stern wrote:
> > > On Sun, Jul 11, 2021 at 09:07:09AM -0700, syzbot wrote:
> > > > Hello,
> > > >
> > > > syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> > > > WARNING in do_proc_control/usb_submit_urb
>
> > > I don't get this. It shouldn't be possible. The fact that the
> > > direction bit is set in both bRequestType and pipe means that the URB
> > > was submitted as a control-IN but had length 0. But the patch addresses
> > > exactly that case:
> > >
> > > --- usb-devel.orig/drivers/usb/core/devio.c
> > > +++ usb-devel/drivers/usb/core/devio.c
> > > @@ -1133,7 +1133,7 @@ static int do_proc_control(struct usb_de
> > > "wIndex=%04x wLength=%04x\n",
> > > ctrl->bRequestType, ctrl->bRequest, ctrl->wValue,
> > > ctrl->wIndex, ctrl->wLength);
> > > - if (ctrl->bRequestType & 0x80) {
> > > + if ((ctrl->bRequestType & USB_DIR_IN) && ctrl->wLength) {
> > > pipe = usb_rcvctrlpipe(dev, 0);
> > > snoop_urb(dev, NULL, pipe, ctrl->wLength, tmo, SUBMIT, NULL, 0);
> > >
> > > and causes the kernel to handle it as a control-OUT instead.
> > >
> > > Johan, any ideas?
> >
> > Did syzbot actually test the patch? I can't see how the direction bit of
> > the pipe argument can be set with the above applied either.
>
> It looks like the second patch you submitted was hand-edited and still
> quoted.
>
> And looking at the dashboard it seems like no patch was applied for your
> second test attempt:
>
> https://syzkaller.appspot.com/bug?extid=72af3105289dcb4c055b
Yes, that explains it. Funny how easy it is to miss those "> "
markings -- you just get too used to them.
> I've been bitten by something like this before when erroneously thinking
> that a test command could be submitted as a reply to a patch.
>
> Perhaps the report mail could include the patch tested or something so
> we don't spend time investigating syzbot interface failures.
Good idea.
Anyway, here's the patch again, this time properly formatted. Hopefully
now it will work.
Alan Stern
#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git ee268dee
Index: usb-devel/drivers/usb/core/devio.c
===================================================================
--- usb-devel.orig/drivers/usb/core/devio.c
+++ usb-devel/drivers/usb/core/devio.c
@@ -1133,7 +1133,7 @@ static int do_proc_control(struct usb_de
"wIndex=%04x wLength=%04x\n",
ctrl->bRequestType, ctrl->bRequest, ctrl->wValue,
ctrl->wIndex, ctrl->wLength);
- if (ctrl->bRequestType & 0x80) {
+ if ((ctrl->bRequestType & USB_DIR_IN) && ctrl->wLength) {
pipe = usb_rcvctrlpipe(dev, 0);
snoop_urb(dev, NULL, pipe, ctrl->wLength, tmo, SUBMIT, NULL, 0);
