TDLS: Add extra validation step for responder RSN IE length

The following kde.rsn_ie_len != peer->rsnie_i_len was already taking
care of enforcing the length to be within the target buffer length.
Anyway, this explicit check makes this clearer and matches the design in
TPK M1 processing.

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

src/rsn_supp/tdls.c

@@ -2098,6 +2098,13 @@ static int wpa_tdls_process_tpk_m2(struct wpa_sm *sm, const u8 *src_addr,
 	wpa_hexdump(MSG_DEBUG, "TDLS: RSN IE Received from TPK M2",
 		    kde.rsn_ie, kde.rsn_ie_len);
 
+	if (kde.rsn_ie_len > TDLS_MAX_IE_LEN) {
+		wpa_printf(MSG_INFO,
+			   "TDLS: Too long Responder RSN IE in TPK M2");
+		status = WLAN_STATUS_INVALID_RSNIE;
+		goto error;
+	}
+
 	/*
 	 * FIX: bitwise comparison of RSN IE is not the correct way of
 	 * validation this. It can be different, but certain fields must