e1000e: guard against buffer overflow in cable length tables

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/net/e1000e/es2lan.c b/drivers/net/e1000e/es2lan.c
index 3ff932f02f29..3f435c16608d 100644
--- a/drivers/net/e1000e/es2lan.c
+++ b/drivers/net/e1000e/es2lan.c
@@ -99,6 +99,8 @@
  */
 static const u16 e1000_gg82563_cable_length_table[] =
          { 0, 60, 115, 150, 150, 60, 115, 150, 180, 180, 0xFF };
+#define GG82563_CABLE_LENGTH_TABLE_SIZE \
+                ARRAY_SIZE(e1000_gg82563_cable_length_table)
 
 static s32 e1000_setup_copper_link_80003es2lan(struct e1000_hw *hw);
 static s32 e1000_acquire_swfw_sync_80003es2lan(struct e1000_hw *hw, u16 mask);
@@ -694,20 +696,27 @@ static s32 e1000_phy_force_speed_duplex_80003es2lan(struct e1000_hw *hw)
 static s32 e1000_get_cable_length_80003es2lan(struct e1000_hw *hw)
 {
         struct e1000_phy_info *phy = &hw->phy;
-        s32 ret_val;
+        s32 ret_val = 0;
         u16 phy_data, index;
 
         ret_val = e1e_rphy(hw, GG82563_PHY_DSP_DISTANCE, &phy_data);
         if (ret_val)
-                return ret_val;
+                goto out;
 
         index = phy_data & GG82563_DSPD_CABLE_LENGTH;
+
+        if (index >= GG82563_CABLE_LENGTH_TABLE_SIZE - 5) {
+                ret_val = -E1000_ERR_PHY;
+                goto out;
+        }
+
         phy->min_cable_length = e1000_gg82563_cable_length_table[index];
-        phy->max_cable_length = e1000_gg82563_cable_length_table[index+5];
+        phy->max_cable_length = e1000_gg82563_cable_length_table[index + 5];
 
         phy->cable_length = (phy->min_cable_length + phy->max_cable_length) / 2;
 
-        return 0;
+out:
+        return ret_val;
 }
 
 /**