[PATCH AUTOSEL 6.6 037/139] wifi: rtw89: correct base HT rate mask for firmware

Sasha Levin
2024-09-25T12:12:55Z

From: Ping-Ke Shih <pkshih@realtek.com>

[ Upstream commit 45742881f9eee2a4daeb6008e648a460dd3742cd ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/realtek/rtw89/phy.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw89/phy.c b/drivers/net/wireless/realtek/rtw89/phy.c
index 7139146cb3fad..fac83b718a30c 100644
--- a/drivers/net/wireless/realtek/rtw89/phy.c
+++ b/drivers/net/wireless/realtek/rtw89/phy.c
@@ -284,8 +284,8 @@ 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;
--
2.43.0