Subject: [PATCH 5.4 25/72] rsi: Fix TX EAPOL packet handling against iwlwifi AP

From: Greg Kroah-Hartman <[email-masked]>
Date: Fri, 5 Mar 2021 13:21:27 +0100

From: Marek Vasut <[email-masked]>

[ Upstream commit 65277100caa2f2c62b6f3c4648b90d6f0435f3bc ]

In case RSI9116 SDIO WiFi operates in STA mode against Intel 9260 in AP mode,
the association fails. The former is using wpa_supplicant during association,
the later is set up using hostapd:

iwl$ cat hostapd.conf
interface=wlp1s0
ssid=test
country_code=DE
hw_mode=g
channel=1
wpa=2
wpa_passphrase=test
wpa_key_mgmt=WPA-PSK
iwl$ hostapd -d hostapd.conf

rsi$ wpa_supplicant -i wlan0 -c <(wpa_passphrase test test)

The problem is that the TX EAPOL data descriptor RSI_DESC_REQUIRE_CFM_TO_HOST
flag and extended descriptor EAPOL4_CONFIRM frame type are not set in case the
AP is iwlwifi, because in that case the TX EAPOL packet is 2 bytes shorter.

The downstream vendor driver has this change in place already [1], however
there is no explanation for it, neither is there any commit history from which
such explanation could be obtained.

[1] https://github.com/SiliconLabs/RS911X-nLink-OSD/blob/master/rsi/rsi_91x_hal.c#L238

Signed-off-by: Marek Vasut <[email-masked]>
Cc: Angus Ainslie <[email-masked]>
Cc: David S. Miller <[email-masked]>
Cc: Jakub Kicinski <[email-masked]>
Cc: Kalle Valo <[email-masked]>
Cc: Lee Jones <[email-masked]>
Cc: Martin Kepplinger <[email-masked]>
Cc: Sebastian Krzyszkowiak <[email-masked]>
Cc: Siva Rebbagondla <[email-masked]>
Cc: [email-masked]
Cc: [email-masked]
Signed-off-by: Kalle Valo <[email-masked]>
Link: https://lore.kernel.org/r/[email-masked]
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/wireless/rsi/rsi_91x_hal.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/rsi/rsi_91x_hal.c b/drivers/net/wireless/rsi/rsi_91x_hal.c
index 6f8d5f9a9f7e..a07304405b2c 100644
--- a/drivers/net/wireless/rsi/rsi_91x_hal.c
+++ b/drivers/net/wireless/rsi/rsi_91x_hal.c
@@ -248,7 +248,8 @@ int rsi_prepare_data_desc(struct rsi_common *common, struct sk_buff *skb)
 			rsi_set_len_qno(&data_desc->len_qno,
 					(skb->len - FRAME_DESC_SZ),
 					RSI_WIFI_MGMT_Q);
-		if ((skb->len - header_size) == EAPOL4_PACKET_LEN) {
+		if (((skb->len - header_size) == EAPOL4_PACKET_LEN) ||
+		    ((skb->len - header_size) == EAPOL4_PACKET_LEN - 2)) {
 			data_desc->misc_flags |=
 				RSI_DESC_REQUIRE_CFM_TO_HOST;
 			xtend_desc->confirm_frame_type = EAPOL4_CONFIRM;
-- 
2.30.1