From: Jacob Keller <jacob.e.keller@intel.com>
Date: Thu, 14 Nov 2019 10:45:01 -0800
Subject: renesas: reject unsupported external timestamp flags
Patch-mainline: v5.4-rc8
Git-commit: 592025a03b34927f35852058c933ffcd7c500321
References: bsc#1176447

Fix the renesas PTP support to explicitly reject any future flags that
get added to the external timestamp request ioctl.

In order to maintain currently functioning code, this patch accepts all
three current flags. This is because the PTP_RISING_EDGE and
PTP_FALLING_EDGE flags have unclear semantics and each driver seems to
have interpreted them slightly differently.

Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/renesas/ravb_ptp.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/net/ethernet/renesas/ravb_ptp.c
+++ b/drivers/net/ethernet/renesas/ravb_ptp.c
@@ -182,6 +182,12 @@ static int ravb_ptp_extts(struct ptp_clo
 	struct net_device *ndev = priv->ndev;
 	unsigned long flags;
 
+	/* Reject requests with unsupported flags */
+	if (req->flags & ~(PTP_ENABLE_FEATURE |
+			   PTP_RISING_EDGE |
+			   PTP_FALLING_EDGE))
+		return -EOPNOTSUPP;
+
 	if (req->index)
 		return -EINVAL;