RSN IBSS: Fix TK clearing on Authentication frame RX

When wpa_supplicant was processing a received Authentication frame (seq
1) from a peer STA for which there was already a TK configured to the
driver, debug log claimed that the PTK gets cleared, but the actual
call to clear the key was actually dropped due to AUTH vs. SUPP set_key
selection. Fix this by explicitly clearing the TK in case it was set
and an Authentication frame (seq 1) is received.

This fixes some cases where EAPOL-Key frames were sent encrypted using
the old key when a peer STA restarted itself and lost the key and had to
re-join the IBSS. Previously, that state required timing out the 4-way
handshake and Deauthentication frame exchange to recover.

Signed-off-by: Jouni Malinen <j@w1.fi>

wpa_supplicant/ibss_rsn.c

@@ -837,6 +837,18 @@ static void ibss_rsn_handle_auth_1_of_2(struct ibss_rsn *ibss_rsn,
 	wpa_printf(MSG_DEBUG, "RSN: IBSS RX Auth frame (SEQ 1) from " MACSTR,
 		   MAC2STR(addr));
 
+	if (peer &&
+	    peer->authentication_status & (IBSS_RSN_SET_PTK_SUPP |
+					   IBSS_RSN_SET_PTK_AUTH)) {
+		/* Clear the TK for this pair to allow recovery from the case
+		 * where the peer STA has restarted and lost its key while we
+		 * still have a pairwise key configured. */
+		wpa_printf(MSG_DEBUG, "RSN: Clear pairwise key for peer "
+			   MACSTR, MAC2STR(addr));
+		wpa_drv_set_key(ibss_rsn->wpa_s, WPA_ALG_NONE, addr, 0, 0,
+				NULL, 0, NULL, 0);
+	}
+
 	if (peer &&
 	    peer->authentication_status & IBSS_RSN_AUTH_EAPOL_BY_PEER) {
 		if (peer->own_auth_tx.sec) {