Subject: Re: [PATCH RFT] ieee802154: atusb: move to new USB API

From: Greg KH <[email-masked]>
Date: Wed, 5 Jan 2022 09:08:39 +0100

On Tue, Jan 04, 2022 at 08:41:23PM +0100, Stefan Schmidt wrote:
> Hello.
> 
> On 03.01.22 16:35, Alexander Aring wrote:
> > Hi,
> > 
> > On Mon, 3 Jan 2022 at 08:03, Greg KH <[email-masked]> wrote:
> > > 
> > > On Sun, Jan 02, 2022 at 08:19:43PM +0300, Pavel Skripkin wrote:
> > > > Alexander reported a use of uninitialized value in
> > > > atusb_set_extended_addr(), that is caused by reading 0 bytes via
> > > > usb_control_msg().
> > > > 
> > > > Since there is an API, that cannot read less bytes, than was requested,
> > > > let's move atusb driver to use it. It will fix all potintial bugs with
> > > > uninit values and make code more modern
> > > > 
> > > > Fail log:
> > > > 
> > > > BUG: KASAN: uninit-cmp in ieee802154_is_valid_extended_unicast_addr include/linux/ieee802154.h:310 [inline]
> > > > BUG: KASAN: uninit-cmp in atusb_set_extended_addr drivers/net/ieee802154/atusb.c:1000 [inline]
> > > > BUG: KASAN: uninit-cmp in atusb_probe.cold+0x29f/0x14db drivers/net/ieee802154/atusb.c:1056
> > > > Uninit value used in comparison: 311daa649a2003bd stack handle: 000000009a2003bd
> > > >   ieee802154_is_valid_extended_unicast_addr include/linux/ieee802154.h:310 [inline]
> > > >   atusb_set_extended_addr drivers/net/ieee802154/atusb.c:1000 [inline]
> > > >   atusb_probe.cold+0x29f/0x14db drivers/net/ieee802154/atusb.c:1056
> > > >   usb_probe_interface+0x314/0x7f0 drivers/usb/core/driver.c:396
> > > > 
> > > > Fixes: 7490b008d123 ("ieee802154: add support for atusb transceiver")
> > > > Cc: [email-masked] # 5.9
> > > > Reported-by: Alexander Potapenko <[email-masked]>
> > > > Signed-off-by: Pavel Skripkin <[email-masked]>
> > > > ---
> > > >   drivers/net/ieee802154/atusb.c | 61 +++++++++++++++++++++-------------
> > > >   1 file changed, 38 insertions(+), 23 deletions(-)
> > > > 
> > > > diff --git a/drivers/net/ieee802154/atusb.c b/drivers/net/ieee802154/atusb.c
> > > > index 23ee0b14cbfa..43befea0110f 100644
> > > > --- a/drivers/net/ieee802154/atusb.c
> > > > +++ b/drivers/net/ieee802154/atusb.c
> > > > @@ -80,10 +80,9 @@ struct atusb_chip_data {
> > > >    * in atusb->err and reject all subsequent requests until the error is cleared.
> > > >    */
> > > > 
> > > > -static int atusb_control_msg(struct atusb *atusb, unsigned int pipe,
> > > > -                          __u8 request, __u8 requesttype,
> > > > -                          __u16 value, __u16 index,
> > > > -                          void *data, __u16 size, int timeout)
> > > > +static int atusb_control_msg_recv(struct atusb *atusb, __u8 request, __u8 requesttype,
> > > > +                               __u16 value, __u16 index,
> > > > +                               void *data, __u16 size, int timeout)
> > > 
> > > Why do you need a wrapper function at all?  Why not just call the real
> > > usb functions instead?
> 
> > ...
> 
> > > 
> > > I would recommend just moving to use the real USB functions and no
> > > wrapper function at all like this, it will make things more obvious and
> > > easier to understand over time.
> > 
> > okay.
> 
> With the small fix handle the actual KASAN report applied now

It was?  What is the git commit id?

thanks,

greg k-h