From: Dongliang Mu <mudongliangabcd@xxxxxxxxx> In idmouse_create_image, if any ftip_command fails, it will go to the reset label. However, this leads to the data in bulk_in_buffer[HEADER..IMGSIZE] uninitialized. And the check for valid image incurs an uninitialized dereference. Fix this by moving the check before reset label since this check only be valid if the data after bulk_in_buffer[HEADER] has concrete data. Note that this is found by KMSAN, so only kernel compilation is tested. Reported-by: syzbot+79832d33eb89fb3cd092@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx> --- drivers/usb/misc/idmouse.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/usb/misc/idmouse.c b/drivers/usb/misc/idmouse.c index e9437a176518..ea39243efee3 100644 --- a/drivers/usb/misc/idmouse.c +++ b/drivers/usb/misc/idmouse.c @@ -177,10 +177,6 @@ static int idmouse_create_image(struct usb_idmouse *dev) bytes_read += bulk_read; } - /* reset the device */ -reset: - ftip_command(dev, FTIP_RELEASE, 0, 0); - /* check for valid image */ /* right border should be black (0x00) */ for (bytes_read = sizeof(HEADER)-1 + WIDTH-1; bytes_read < IMGSIZE; bytes_read += WIDTH) @@ -192,6 +188,10 @@ static int idmouse_create_image(struct usb_idmouse *dev) if (dev->bulk_in_buffer[bytes_read] != 0xFF) return -EAGAIN; + /* reset the device */ +reset: + ftip_command(dev, FTIP_RELEASE, 0, 0); + /* should be IMGSIZE == 65040 */ dev_dbg(&dev->interface->dev, "read %d bytes fingerprint data\n", bytes_read); -- 2.25.1
