[PATCH rtw-next v5 02/10] wifi: rtw89: handle negative rate index for injected frames

[Enver Ikromov]

When the radiotap header of an injected frame carries no rate,
info->control.rates[0].idx is -1. rtw89_core_tx_update_injection()
stores the index in a u8, so the value becomes 0xff and is added to
the CCK1/OFDM6 base, programming an invalid hardware rate into the TX
descriptor.

Use a signed index. If it is negative, keep the rate already selected
by rtw89_core_tx_update_mgmt_info() for management frames, and fall
back to data_retry_lowest_rate (or OFDM6 when
IEEE80211_TX_CTL_NO_CCK_RATE is set) for data frames.

Fixes: e96abe4fd7cd ("wifi: rtw89: consider data rate/bandwidth/GI for injected packets")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Enver Ikromov <owner@xxxxxxxxxxxxxx>
---
 drivers/net/wireless/realtek/rtw89/core.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw89/core.c b/drivers/net/wireless/realtek/rtw89/core.c
index b7df97e..527593e 100644
--- a/drivers/net/wireless/realtek/rtw89/core.c
+++ b/drivers/net/wireless/realtek/rtw89/core.c
@@ -1239,12 +1239,25 @@ static void rtw89_core_tx_update_injection(struct rtw89_dev *rtwdev,
 	enum mac80211_rate_control_flags flags = info->control.rates[0].flags;
 	struct rtw89_tx_desc_info *desc_info = &tx_req->desc_info;
 	const struct rtw89_chan *chan;
-	u8 idx = info->control.rates[0].idx;
+	s8 idx = info->control.rates[0].idx;
 	u8 nss, mcs;
 
 	desc_info->use_rate = true;
 	desc_info->dis_data_fb = true;
 
+	/* No rate was given in the radiotap header. Management frames
+	 * already carry the rate from rtw89_core_tx_update_mgmt_info(), so
+	 * only data frames need a fallback.
+	 */
+	if (idx < 0) {
+		if (tx_req->tx_type == RTW89_CORE_TX_TYPE_DATA)
+			desc_info->data_rate =
+				info->flags & IEEE80211_TX_CTL_NO_CCK_RATE ?
+				RTW89_HW_RATE_OFDM6 :
+				desc_info->data_retry_lowest_rate;
+		return;
+	}
+
 	if (flags & IEEE80211_TX_RC_160_MHZ_WIDTH)
 		desc_info->data_bw = 3;
 	else if (flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
-- 
2.56.0.windows.4