From: Dongliang Mu <mudongliangabcd@xxxxxxxxx> [ Upstream commit bce2b0539933e485d22d6f6f076c0fcd6f185c4c ] 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> Link: https://lore.kernel.org/r/20220922134847.1101921-1-dzm91@xxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 01ef2551be46..974b8d0621bd 100644 --- a/drivers/usb/misc/idmouse.c +++ b/drivers/usb/misc/idmouse.c @@ -182,10 +182,6 @@ 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) @@ -197,6 +193,10 @@ 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); -- 2.35.1
