| Date | Fri, 3 Jan 2020 16:02:42 +0100 | From | Johan Hovold <> | Subject | Re: [PATCH 5.4 106/434] media: flexcop-usb: fix NULL-ptr deref in flexcop_usb_transfer_init() |
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On Sun, Dec 29, 2019 at 06:22:39PM +0100, Greg Kroah-Hartman wrote: > From: Yang Yingliang <yangyingliang@huawei.com> > > [ Upstream commit 649cd16c438f51d4cd777e71ca1f47f6e0c5e65d ] > > If usb_set_interface() failed, iface->cur_altsetting will > not be assigned and it will be used in flexcop_usb_transfer_init() > It may lead a NULL pointer dereference. > > Check usb_set_interface() return value in flexcop_usb_init() > and return failed to avoid using this NULL pointer. > > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> > Signed-off-by: Sean Young <sean@mess.org> > Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> > Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is bogus and should be dropped from all stable queues.
Contrary to what the commit message claims, iface->cur_altsetting will never be NULL so there's no risk for a NULL-pointer dereference here.
Even though the change itself is benign, we shouldn't spread this confusion further.
> --- > drivers/media/usb/b2c2/flexcop-usb.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/usb/b2c2/flexcop-usb.c b/drivers/media/usb/b2c2/flexcop-usb.c > index 1a801dc286f8..d1331f828108 100644 > --- a/drivers/media/usb/b2c2/flexcop-usb.c > +++ b/drivers/media/usb/b2c2/flexcop-usb.c > @@ -504,7 +504,13 @@ urb_error: > static int flexcop_usb_init(struct flexcop_usb *fc_usb) > { > /* use the alternate setting with the larges buffer */ > - usb_set_interface(fc_usb->udev,0,1); > + int ret = usb_set_interface(fc_usb->udev, 0, 1); > + > + if (ret) { > + err("set interface failed."); > + return ret; > + } > + > switch (fc_usb->udev->speed) { > case USB_SPEED_LOW: > err("cannot handle USB speed because it is too slow.");
Johan
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