RE: [Intel-wired-lan] [PATCH][next][V2] ixgbe: fix potential u32 overflow on shift

[Bowers, AndrewX]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@xxxxxxxxxx] On
> Behalf Of Colin King
> Sent: Friday, June 7, 2019 11:19 AM
> To: Keller, Jacob E <jacob.e.keller@xxxxxxxxx>; Kirsher, Jeffrey T
> <jeffrey.t.kirsher@xxxxxxxxx>; David S . Miller <davem@xxxxxxxxxxxxx>;
> intel-wired-lan@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx
> Cc: kernel-janitors@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [Intel-wired-lan] [PATCH][next][V2] ixgbe: fix potential u32
> overflow on shift
> 
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> 
> The u32 variable rem is being shifted using u32 arithmetic however it is being
> passed to div_u64 that expects the expression to be a u64.
> The 32 bit shift may potentially overflow, so cast rem to a u64 before shifting
> to avoid this.  Also remove comment about overflow.
> 
> Addresses-Coverity: ("Unintentional integer overflow")
> Fixes: cd4583206990 ("ixgbe: implement support for SDP/PPS output on X550
> hardware")
> Fixes: 68d9676fc04e ("ixgbe: fix PTP SDP pin setup on X540 hardware")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> 
> V2: update comment
> 
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c | 14 ++++----------
>  1 file changed, 4 insertions(+), 10 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@xxxxxxxxx>