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, 11 insertions, 3 deletions

diff --git a/drivers/net/e1000e/phy.c b/drivers/net/e1000e/phy.c
index 5cd01c691c53..9ce499734dca 100644
--- a/drivers/net/e1000e/phy.c
+++ b/drivers/net/e1000e/phy.c
@@ -44,6 +44,8 @@ static s32 e1000_access_phy_debug_regs_hv(struct e1000_hw *hw, u32 offset,
 /* Cable length tables */
 static const u16 e1000_m88_cable_length_table[] =
         { 0, 50, 80, 110, 140, 140, E1000_CABLE_LENGTH_UNDEFINED };
+#define M88E1000_CABLE_LENGTH_TABLE_SIZE \
+                ARRAY_SIZE(e1000_m88_cable_length_table)
 
 static const u16 e1000_igp_2_cable_length_table[] =
         { 0, 0, 0, 0, 0, 0, 0, 0, 3, 5, 8, 11, 13, 16, 18, 21, 0, 0, 0, 3,
@@ -1717,15 +1719,21 @@ s32 e1000e_get_cable_length_m88(struct e1000_hw *hw)
 
         ret_val = e1e_rphy(hw, M88E1000_PHY_SPEC_STATUS, &phy_data);
         if (ret_val)
-                return ret_val;
+                goto out;
 
         index = (phy_data & M88E1000_PSSR_CABLE_LENGTH) >>
-                M88E1000_PSSR_CABLE_LENGTH_SHIFT;
+                M88E1000_PSSR_CABLE_LENGTH_SHIFT;
+        if (index >= M88E1000_CABLE_LENGTH_TABLE_SIZE - 1) {
+                ret_val = -E1000_ERR_PHY;
+                goto out;
+        }
+
         phy->min_cable_length = e1000_m88_cable_length_table[index];
-        phy->max_cable_length = e1000_m88_cable_length_table[index+1];
+        phy->max_cable_length = e1000_m88_cable_length_table[index + 1];
 
         phy->cable_length = (phy->min_cable_length + phy->max_cable_length) / 2;
 
+out:
         return ret_val;
 }