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Subject[PATCH][next] can: usb: fix potential integer overflow on shift of a int
Date
From: Colin Ian King <colin.king@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.king@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
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