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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Colin Ian King <colin.king@canonical.com>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.4 21/38] can: peak_usb: fix potential integer overflow on shift of a int
Date:   Mon, 23 Nov 2020 13:22:07 +0100
Message-Id: <20201123121805.325118365@linuxfoundation.org>
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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 22deddb2dbf5a..7b148174eb760 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -176,7 +176,7 @@ void peak_usb_get_ts_tv(struct peak_time_ref *time_ref, u32 ts,
 		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.
@@ -188,7 +188,7 @@ void peak_usb_get_ts_tv(struct peak_time_ref *time_ref, u32 ts,
 		 *              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