[PATCH 4.4 060/105] bnx2x: prevent crash when accessing PTP with interface down

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michal Schmidt <mschmidt@xxxxxxxxxx>


[ Upstream commit 466e8bf10ac104d96e1ea813e8126e11cb72ea20 ]

It is possible to crash the kernel by accessing a PTP device while its
associated bnx2x interface is down. Before the interface is brought up,
the timecounter is not initialized, so accessing it results in NULL
dereference.

Fix it by checking if the interface is up.

Use -ENETDOWN as the error code when the interface is down.
 -EFAULT in bnx2x_ptp_adjfreq() did not seem right.

Tested using phc_ctl get/set/adj/freq commands.

Signed-off-by: Michal Schmidt <mschmidt@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c |   20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
@@ -13646,7 +13646,7 @@ static int bnx2x_ptp_adjfreq(struct ptp_
 	if (!netif_running(bp->dev)) {
 		DP(BNX2X_MSG_PTP,
 		   "PTP adjfreq called while the interface is down\n");
-		return -EFAULT;
+		return -ENETDOWN;
 	}
 
 	if (ppb < 0) {
@@ -13705,6 +13705,12 @@ static int bnx2x_ptp_adjtime(struct ptp_
 {
 	struct bnx2x *bp = container_of(ptp, struct bnx2x, ptp_clock_info);
 
+	if (!netif_running(bp->dev)) {
+		DP(BNX2X_MSG_PTP,
+		   "PTP adjtime called while the interface is down\n");
+		return -ENETDOWN;
+	}
+
 	DP(BNX2X_MSG_PTP, "PTP adjtime called, delta = %llx\n", delta);
 
 	timecounter_adjtime(&bp->timecounter, delta);
@@ -13717,6 +13723,12 @@ static int bnx2x_ptp_gettime(struct ptp_
 	struct bnx2x *bp = container_of(ptp, struct bnx2x, ptp_clock_info);
 	u64 ns;
 
+	if (!netif_running(bp->dev)) {
+		DP(BNX2X_MSG_PTP,
+		   "PTP gettime called while the interface is down\n");
+		return -ENETDOWN;
+	}
+
 	ns = timecounter_read(&bp->timecounter);
 
 	DP(BNX2X_MSG_PTP, "PTP gettime called, ns = %llu\n", ns);
@@ -13732,6 +13744,12 @@ static int bnx2x_ptp_settime(struct ptp_
 	struct bnx2x *bp = container_of(ptp, struct bnx2x, ptp_clock_info);
 	u64 ns;
 
+	if (!netif_running(bp->dev)) {
+		DP(BNX2X_MSG_PTP,
+		   "PTP settime called while the interface is down\n");
+		return -ENETDOWN;
+	}
+
 	ns = timespec64_to_ns(ts);
 
 	DP(BNX2X_MSG_PTP, "PTP settime called, ns = %llu\n", ns);