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    Subject[PATCH 4.14 34/60] can: peak_usb: fix potential integer overflow on shift of a int
    Date
    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 9d78ba7776140..c9d86d50bf886 100644
    --- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
    +++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
    @@ -180,7 +180,7 @@ 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.
    @@ -192,7 +192,7 @@ 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


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