From c3cf76db75c0a3051c0967e3915ce3c5a6a33078 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Wed, 5 Aug 2020 03:10:47 +0300 Subject: [PATCH] ptp: only allow phase values lower than 1 period The way we define the phase (the difference between the time of the signal's rising edge, and the closest integer multiple of the period), it doesn't make sense to have a phase value equal or larger than 1 period. So deny these settings coming from the user. Signed-off-by: Vladimir Oltean Acked-by: Richard Cochran Acked-by: Jacob Keller Signed-off-by: David S. Miller --- drivers/ptp/ptp_chardev.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c index e0e6f85966e19..af3bc65c4595d 100644 --- a/drivers/ptp/ptp_chardev.c +++ b/drivers/ptp/ptp_chardev.c @@ -218,6 +218,19 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg) break; } } + if (perout->flags & PTP_PEROUT_PHASE) { + /* + * The phase should be specified modulo the + * period, therefore anything equal or larger + * than 1 period is invalid. + */ + if (perout->phase.sec > perout->period.sec || + (perout->phase.sec == perout->period.sec && + perout->phase.nsec >= perout->period.nsec)) { + err = -ERANGE; + break; + } + } } else if (cmd == PTP_PEROUT_REQUEST) { req.perout.flags &= PTP_PEROUT_V1_VALID_FLAGS; req.perout.rsv[0] = 0; -- 2.39.5