[PATCH][next] can: usb: fix potential integer overflow on shift of a int

[Colin King]

From: Colin Ian King <colin.k...@canonical.com>

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.

Addresses-Coverity: ("Unintentional integer overflow")
Fixes: bb4785551f64 ("can: usb: PEAK-System Technik USB adapters driver core")
Signed-off-by: Colin Ian King <colin.k...@canonical.com>
---
 drivers/net/can/usb/peak_usb/pcan_usb_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

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 c2764799f9ef..204ccb27d6d9 100644
--- 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 */
-- 
2.27.0