[PATCH net] ice: fix theoretical out-of-bounds access in ethtool link modes

[Michal Schmidt <mschmidt@redhat.com>]

To map phy types reported by the hardware to ethtool link mode bits,
ice uses two lookup tables (phy_type_low_lkup, phy_type_high_lkup).
The "low" table has 64 elements to cover every possible bit the hardware
may report, but the "high" table has only 13. If the hardware reports a
higher bit in phy_types_high, the driver would access memory beyond the
lookup table's end.

Instead of iterating through all 64 bits of phy_types_{low,high}, use
the sizes of the respective lookup tables.

Fixes: 9136e1f1e5c3 ("ice: refactor PHY type to ethtool link mode")
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
---
 drivers/net/ethernet/intel/ice/ice_ethtool.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c
index a34083567e6f..bde9bc74f928 100644
--- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -1850,14 +1850,14 @@ ice_phy_type_to_ethtool(struct net_device *netdev,
 	linkmode_zero(ks->link_modes.supported);
 	linkmode_zero(ks->link_modes.advertising);
 
-	for (i = 0; i < BITS_PER_TYPE(u64); i++) {
+	for (i = 0; i < ARRAY_SIZE(phy_type_low_lkup); i++) {
 		if (phy_types_low & BIT_ULL(i))
 			ice_linkmode_set_bit(&phy_type_low_lkup[i], ks,
 					     req_speeds, advert_phy_type_lo,
 					     i);
 	}
 
-	for (i = 0; i < BITS_PER_TYPE(u64); i++) {
+	for (i = 0; i < ARRAY_SIZE(phy_type_high_lkup); i++) {
 		if (phy_types_high & BIT_ULL(i))
 			ice_linkmode_set_bit(&phy_type_high_lkup[i], ks,
 					     req_speeds, advert_phy_type_hi,
-- 
2.41.0