can: peak_usb: fix potential integer overflow on shift of a int

The left shift of int 32 bit integer constant 1 is evaluated using 32 bit
arithmetic and then assigned to a signed 64 bit variable. In the case where
time_ref->adapter->ts_used_bits is 32 or more this can lead to an oveflow.
Avoid this by shifting using the BIT_ULL macro instead.

Fixes: bb4785551f64 ("can: usb: PEAK-System Technik USB adapters driver core")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20201105112427.40688-1-colin.king@canonical.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
index c276479..204ccb2 100644 (file)
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -156,7 +156,7 @@ void peak_usb_get_ts_time(struct peak_time_ref *time_ref, u32 ts, ktime_t *time)
                if (time_ref->ts_dev_1 < time_ref->ts_dev_2) {
                        /* case when event time (tsw) wraps */
                        if (ts < time_ref->ts_dev_1)
-                               delta_ts = 1 << time_ref->adapter->ts_used_bits;
+                               delta_ts = BIT_ULL(time_ref->adapter->ts_used_bits);
 
                /* Otherwise, sync time counter (ts_dev_2) has wrapped:
                 * handle case when event time (tsn) hasn't.
@@ -168,7 +168,7 @@ void peak_usb_get_ts_time(struct peak_time_ref *time_ref, u32 ts, ktime_t *time)
                 *              tsn            ts
                 */
                } else if (time_ref->ts_dev_1 < ts) {
-                       delta_ts = -(1 << time_ref->adapter->ts_used_bits);
+                       delta_ts = -BIT_ULL(time_ref->adapter->ts_used_bits);
                }
 
                /* add delay between last sync and event timestamps */