[RFC] netdev: avoid PMKSA for fullmac drivers

The fullmac drivers need additional support to correctly work with
PMKSA. This can be disabled via main.conf, but to avoid extra user
configuration avoid the use of PMKSA for fullmac drivers
automatically.
---
 src/netdev.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/netdev.c b/src/netdev.c
index 2a6d94fc..7af3c39a 100644
--- a/src/netdev.c
+++ b/src/netdev.c
@@ -1518,7 +1518,8 @@ static void try_handshake_complete(struct netdev_handshake_state *nhs)
 
 		l_debug("Invoking handshake_event()");
 
-		handshake_state_cache_pmksa(&nhs->super);
+		if (nhs->type != CONNECTION_TYPE_FULLMAC)
+			handshake_state_cache_pmksa(&nhs->super);
 
 		if (handshake_event(&nhs->super, HANDSHAKE_EVENT_COMPLETE))
 			return;
@@ -2455,6 +2456,19 @@ static void netdev_driver_connected(struct netdev *netdev)
 		eapol_register(netdev->sm);
 }
 
+static bool netdev_handshake_can_use_pmksa(struct netdev_handshake_state *nhs)
+{
+	/*
+	 * Do not use PMKSA if this is a fullmac driver as they need additional
+	 * support (SET_PMKSA) in order to function properly. Until this support
+	 * is added fullmac drivers will not utilize PMKSA.
+	 */
+	if (nhs->type == CONNECTION_TYPE_FULLMAC)
+		return false;
+
+	return nhs->super.have_pmksa;
+}
+
 static struct l_genl_msg *netdev_build_cmd_connect(struct netdev *netdev,
 						struct handshake_state *hs,
 						const uint8_t *prev_bssid)
@@ -2473,7 +2487,8 @@ static struct l_genl_msg *netdev_build_cmd_connect(struct netdev *netdev,
 	 *       0 (open) for FT Initial Mobility Domain Association over
 	 *         PMKSA caching
 	 */
-	uint32_t auth_type = IE_AKM_IS_SAE(hs->akm_suite) && !hs->have_pmksa ?
+	uint32_t auth_type = IE_AKM_IS_SAE(hs->akm_suite) &&
+					!netdev_handshake_can_use_pmksa(nhs) ?
 					NL80211_AUTHTYPE_SAE :
 					NL80211_AUTHTYPE_OPEN_SYSTEM;
 	enum mpdu_management_subtype subtype = prev_bssid ?
@@ -4053,7 +4068,8 @@ static void netdev_connect_common(struct netdev *netdev,
 	 * If SAE, and we have a valid PMKSA cache we can skip the entire SAE
 	 * protocol and authenticate using the cached keys.
 	 */
-	if (IE_AKM_IS_SAE(hs->akm_suite) && hs->have_pmksa) {
+	if (IE_AKM_IS_SAE(hs->akm_suite) &&
+					netdev_handshake_can_use_pmksa(nhs)) {
 		l_debug("Skipping SAE by using PMKSA cache");
 		goto build_cmd_connect;
 	}
-- 
2.34.1