[PATCH 5.4 080/158] can: peak_usb: fix potential integer overflow on shift of a int

Greg Kroah-Hartman
2020-11-23T12:37:37Z

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

[ Upstream commit 8a68cc0d690c9e5730d676b764c6f059343b842c ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 c844c6abe5fcd..f22089101cdda 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