[PATCH 10/23] wifi: mt76: mt7925: install NAN BIP keys standalone in sta_key_tlv

[Sean Wang]

From: Chengwei Yu <chengwei.yu at mediatek.com>

mt7925_mcu_sta_key_tlv() packs a BIP_CMAC_128 key together with the CCMP
key that sta_key_conf cached from an earlier key installation on the same
link: cipher_id BIP_CMAC_128, key_len 32, the CCMP key in the first 16
bytes and the CMAC key in the second 16, indexed by the CCMP key's id.
That matches STA/AP mode, where the IGTK always follows the GTK on the
same WTBL.

A NAN interface has no such pairing. No CCMP key is ever installed on a
NAN or NAN_DATA interface WTBL, so sta_key_conf is still zeroed when a NAN
TX IGTK/BIGTK arrives: the command would carry 16 bytes of zeros as the
first half of the key material and key_id 0 instead of the real 4-7 key
index.

Restrict the combined-key path to non-NAN interfaces so that a NAN BIP key
takes the generic path instead and is installed standalone, with its own
keyidx and its own 16-byte key material.

Co-developed-by: Sean Wang <sean.wang at mediatek.com>
Signed-off-by: Sean Wang <sean.wang at mediatek.com>
Signed-off-by: Chengwei Yu <chengwei.yu at mediatek.com>
---
 drivers/net/wireless/mediatek/mt76/mt7925/mcu.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
index 76dcbbffabfc..d494753cdf04 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
@@ -1378,7 +1378,15 @@ mt7925_mcu_sta_key_tlv(struct mt76_wcid *wcid,
 		if (cipher == CONNAC3_CIPHER_NONE)
 			return -EOPNOTSUPP;
 
-		if (cipher == CONNAC3_CIPHER_BIP_CMAC_128) {
+		/* STA/AP mode installs the IGTK together with the CCMP GTK that
+		 * sta_key_conf cached earlier on the same link.  NAN has no such
+		 * pairing: no CCMP key is ever installed on a NAN interface WTBL,
+		 * so sta_key_conf would contribute a zero key and a stale key_id.
+		 * Install the NAN BIP key standalone via the generic path instead.
+		 */
+		if (cipher == CONNAC3_CIPHER_BIP_CMAC_128 &&
+		    vif->type != NL80211_IFTYPE_NAN &&
+		    vif->type != NL80211_IFTYPE_NAN_DATA) {
 			sec->cipher_id = CONNAC3_CIPHER_BIP_CMAC_128;
 			sec->key_id = sta_key_conf->keyidx;
 			sec->key_len = 32;
-- 
2.43.0