Re: [PATCH v2] ieee802154: atusb: fix uninit value in atusb_set_extended_addr

[Alexander Aring]

Hi,

On Mon, 3 Jan 2022 at 07:09, Pavel Skripkin <paskripkin@xxxxxxxxx> wrote:
>
> Alexander reported a use of uninitialized value in
> atusb_set_extended_addr(), that is caused by reading 0 bytes via
> usb_control_msg().
>
> Fix it by validating if the number of bytes transferred is actually
> correct, since usb_control_msg() may read less bytes, than was requested
> by caller.
>
> 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")
> Reported-by: Alexander Potapenko <glider@xxxxxxxxxx>
> Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>

Acked-by: Alexander Aring <aahringo@xxxxxxxxxx>

Although I think if such error exists the most common solution would
be to replug the usb device and hope it gets resolved? A retry with a
maximum amount would be another try... However, let's hope those
errors are rare and we care about them when they occur.

Thanks.

- Alex