HID: wacom: avoid integer overflow in wacom_intuos_inout()

If high bit is set to 1 in ((data[3] & 0x0f << 28), after all arithmetic
operations and integer promotions are done, high bits in
wacom->serial[idx] will be filled with 1s as well.
Avoid this, albeit unlikely, issue by specifying left operand's __u64
type for the right operand.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 3bea733ab212 ("USB: wacom tablet driver reorganization")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index dc0f7d9..2ccf838 100644 (file)
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -831,7 +831,7 @@ static int wacom_intuos_inout(struct wacom_wac *wacom)
        /* Enter report */
        if ((data[1] & 0xfc) == 0xc0) {
                /* serial number of the tool */
-               wacom->serial[idx] = ((data[3] & 0x0f) << 28) +
+               wacom->serial[idx] = ((__u64)(data[3] & 0x0f) << 28) +
                        (data[4] << 20) + (data[5] << 12) +
                        (data[6] << 4) + (data[7] >> 4);