EAP server: Extend EAP-TLS Commitment Message use to PEAP and EAP-TTLS

Use the explicit Commitment Message per draft-ietf-emu-eap-tls13-13
Section 2.5 and extend this functionality to PEAP and EAP-TTLS when
using TLS 1.3.

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>

src/eap_server/eap_server_peap.c

@@ -512,7 +512,25 @@ static struct wpabuf * eap_peap_build_phase2_term(struct eap_sm *sm,
 	encr_req = eap_server_tls_encrypt(sm, &data->ssl, &msgbuf);
 	os_free(hdr);
 
-	return encr_req;
+	if (!data->ssl.tls_v13 ||
+	    !tls_connection_resumed(sm->cfg->ssl_ctx, data->ssl.conn)) {
+		wpabuf_free(data->ssl.tls_out);
+		data->ssl.tls_out_pos = 0;
+		return encr_req;
+	}
+
+	if (wpabuf_resize(&data->ssl.tls_out, wpabuf_len(encr_req)) < 0) {
+		wpa_printf(MSG_INFO,
+			   "EAP-PEAP: Failed to resize output buffer");
+		wpabuf_free(encr_req);
+		return NULL;
+	}
+	wpabuf_put_buf(data->ssl.tls_out, encr_req);
+	wpa_hexdump_buf(MSG_DEBUG,
+			"EAP-PEAP: Data appended to the message", encr_req);
+	os_free(encr_req);
+
+	return data->ssl.tls_out;
 }
 
 
@@ -561,8 +579,6 @@ static struct wpabuf * eap_peap_buildReq(struct eap_sm *sm, void *priv, u8 id)
 		data->ssl.tls_out = eap_peap_build_phase2_tlv(sm, data, id);
 		break;
 	case SUCCESS_REQ:
-		wpabuf_free(data->ssl.tls_out);
-		data->ssl.tls_out_pos = 0;
 		data->ssl.tls_out = eap_peap_build_phase2_term(sm, data, id,
 							       1);
 		break;

src/eap_server/eap_server_tls.c

@@ -266,39 +266,6 @@ static void eap_tls_process_msg(struct eap_sm *sm, void *priv,
 		eap_tls_state(data, FAILURE);
 		return;
 	}
-
-	if (data->ssl.tls_v13 &&
-	    tls_connection_established(sm->cfg->ssl_ctx, data->ssl.conn)) {
-		struct wpabuf *plain, *encr;
-
-		wpa_printf(MSG_DEBUG,
-			   "EAP-TLS: Send empty application data to indicate end of exchange");
-		/* FIX: This should be an empty application data based on
-		 * draft-ietf-emu-eap-tls13-05, but OpenSSL does not allow zero
-		 * length payload (SSL_write() documentation explicitly
-		 * describes this as not allowed), so work around that for now
-		 * by sending out a payload of one octet. Hopefully the draft
-		 * specification will change to allow this so that no crypto
-		 * library changes are needed. */
-		plain = wpabuf_alloc(1);
-		if (!plain)
-			return;
-		wpabuf_put_u8(plain, 0);
-		encr = eap_server_tls_encrypt(sm, &data->ssl, plain);
-		wpabuf_free(plain);
-		if (!encr)
-			return;
-		if (wpabuf_resize(&data->ssl.tls_out, wpabuf_len(encr)) < 0) {
-			wpa_printf(MSG_INFO,
-				   "EAP-TLS: Failed to resize output buffer");
-			wpabuf_free(encr);
-			return;
-		}
-		wpabuf_put_buf(data->ssl.tls_out, encr);
-		wpa_hexdump_buf(MSG_DEBUG,
-				"EAP-TLS: Data appended to the message", encr);
-		wpabuf_free(encr);
-	}
 }
 
 

src/eap_server/eap_server_tls_common.c

@@ -366,6 +366,56 @@ int eap_server_tls_phase1(struct eap_sm *sm, struct eap_ssl_data *data)
 		sm->serial_num = tls_connection_peer_serial_num(
 			sm->cfg->ssl_ctx, data->conn);
 
+	/*
+	 * https://tools.ietf.org/html/draft-ietf-emu-eap-tls13#section-2.5
+	 *
+	 * We need to signal the other end that TLS negotiation is done. We
+	 * can't send a zero-length application data message, so we send
+	 * application data which is one byte of zero.
+	 *
+	 * Note this is only done for when there is no application data to be
+	 * sent. So this is done always for EAP-TLS but notibly not for PEAP
+	 * even on resumption.
+	 */
+	if (data->tls_v13 &&
+	    tls_connection_established(sm->cfg->ssl_ctx, data->conn)) {
+		struct wpabuf *plain, *encr;
+
+		switch (sm->currentMethod) {
+		case EAP_TYPE_PEAP:
+			break;
+		default:
+			if (!tls_connection_resumed(sm->cfg->ssl_ctx,
+						    data->conn))
+				break;
+			/* fallthrough */
+		case EAP_TYPE_TLS:
+			wpa_printf(MSG_DEBUG,
+				   "EAP-TLS: Send Commitment Message");
+
+			plain = wpabuf_alloc(1);
+			if (!plain)
+				return -1;
+			wpabuf_put_u8(plain, 0);
+			encr = eap_server_tls_encrypt(sm, data, plain);
+			wpabuf_free(plain);
+			if (!encr)
+				return -1;
+			if (wpabuf_resize(&data->tls_out, wpabuf_len(encr)) < 0)
+			{
+				wpa_printf(MSG_INFO,
+					   "EAP-TLS: Failed to resize output buffer");
+				wpabuf_free(encr);
+				return -1;
+			}
+			wpabuf_put_buf(data->tls_out, encr);
+			wpa_hexdump_buf(MSG_DEBUG,
+					"EAP-TLS: Data appended to the message",
+					encr);
+			wpabuf_free(encr);
+		}
+	}
+
 	return 0;
 }