From: Miroslav Lichvar <mlichvar@xxxxxxxxxx> Subject: drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl The PPS assert/clear offset corrections are set by the PPS_SETPARAMS ioctl in the pps_ktime structs, which also contain flags. The flags are not initialized by applications (using the timepps.h header) and they are not used by the kernel for anything except returning them back in the PPS_GETPARAMS ioctl. Set the flags to zero to make it clear they are unused and avoid leaking uninitialized data of the PPS_SETPARAMS caller to other applications that have a read access to the PPS device. Link: http://lkml.kernel.org/r/20190702092251.24303-1-mlichvar@xxxxxxxxxx Signed-off-by: Miroslav Lichvar <mlichvar@xxxxxxxxxx> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Rodolfo Giometti <giometti@xxxxxxxxxxxx> Cc: Greg KH <greg@xxxxxxxxx> Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/pps/pps.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/pps/pps.c~pps-clear-offset-flags-in-pps_setparams-ioctl +++ a/drivers/pps/pps.c @@ -152,6 +152,14 @@ static long pps_cdev_ioctl(struct file * pps->params.mode |= PPS_CANWAIT; pps->params.api_version = PPS_API_VERS; + /* + * Clear unused fields of pps_kparams to avoid leaking + * uninitialized data of the PPS_SETPARAMS caller via + * PPS_GETPARAMS + */ + pps->params.assert_off_tu.flags = 0; + pps->params.clear_off_tu.flags = 0; + spin_unlock_irq(&pps->lock); break; _
