wifi: rtw89: correct base HT rate mask for firmware

Coverity reported that u8 rx_mask << 24 will become signed 32 bits, which
casting to unsigned 64 bits will do sign extension. For example,
putting 0x80000000 (signed 32 bits) to a u64 variable will become
0xFFFFFFFF_80000000.

The real case we meet is:
  rx_mask[0...3] = ff ff 00 00
  ra_mask = 0xffffffff_ff0ff000

After this fix:
  rx_mask[0...3] = ff ff 00 00
  ra_mask = 0x00000000_ff0ff000

Fortunately driver does bitwise-AND with incorrect ra_mask and supported
rates (1ss and 2ss rate only) afterward, so the final rate mask of
original code is still correct.

Addresses-Coverity-ID: 1504762 ("Unintended sign extension")

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240809072012.84152-5-pkshih@realtek.com

diff --git a/drivers/net/wireless/realtek/rtw89/phy.c b/drivers/net/wireless/realtek/rtw89/phy.c
index aa4fc911599555aa65da4fc835e4b3855f71b247..7306fb679e9551edcce3438407e11dd01820027a 100644 (file)
--- a/drivers/net/wireless/realtek/rtw89/phy.c
+++ b/drivers/net/wireless/realtek/rtw89/phy.c
@@ -356,8 +356,8 @@ static void rtw89_phy_ra_sta_update(struct rtw89_dev *rtwdev,
                csi_mode = RTW89_RA_RPT_MODE_HT;
                ra_mask |= ((u64)sta->deflink.ht_cap.mcs.rx_mask[3] << 48) |
                           ((u64)sta->deflink.ht_cap.mcs.rx_mask[2] << 36) |
-                          (sta->deflink.ht_cap.mcs.rx_mask[1] << 24) |
-                          (sta->deflink.ht_cap.mcs.rx_mask[0] << 12);
+                          ((u64)sta->deflink.ht_cap.mcs.rx_mask[1] << 24) |
+                          ((u64)sta->deflink.ht_cap.mcs.rx_mask[0] << 12);
                high_rate_masks = rtw89_ra_mask_ht_rates;
                if (sta->deflink.ht_cap.cap & IEEE80211_HT_CAP_RX_STBC)
                        stbc_en = 1;