[PATCH 4.9 07/62] net: phy: marvell: Fix buffer overrun with stats counters

[Greg Kroah-Hartman]

From: Andrew Lunn <and...@lunn.ch>

[ Upstream commit fdfdf86720a34527f777cbe0d8599bf0528fa146 ]

marvell_get_sset_count() returns how many statistics counters there
are. If the PHY supports fibre, there are 3, otherwise two.

marvell_get_strings() does not make this distinction, and always
returns 3 strings. This then often results in writing past the end
of the buffer for the strings.

Fixes: 2170fef78a40 ("Marvell phy: add field to get errors from fiber link.")
Signed-off-by: Andrew Lunn <and...@lunn.ch>
Reviewed-by: Florian Fainelli <f.faine...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/phy/marvell.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -1429,9 +1429,10 @@ static int marvell_get_sset_count(struct
 
 static void marvell_get_strings(struct phy_device *phydev, u8 *data)
 {
+       int count = marvell_get_sset_count(phydev);
        int i;
 
-       for (i = 0; i < ARRAY_SIZE(marvell_hw_stats); i++) {
+       for (i = 0; i < count; i++) {
                memcpy(data + i * ETH_GSTRING_LEN,
                       marvell_hw_stats[i].string, ETH_GSTRING_LEN);
        }
@@ -1470,9 +1471,10 @@ static u64 marvell_get_stat(struct phy_d
 static void marvell_get_stats(struct phy_device *phydev,
                              struct ethtool_stats *stats, u64 *data)
 {
+       int count = marvell_get_sset_count(phydev);
        int i;
 
-       for (i = 0; i < ARRAY_SIZE(marvell_hw_stats); i++)
+       for (i = 0; i < count; i++)
                data[i] = marvell_get_stat(phydev, i);
 }