EAP-PEAP: Key derivation per draft-ietf-emu-tls-eap-types-00

Use the TLS-Exporter with the label and context as defined in
draft-ietf-emu-tls-eap-types-00 when deriving keys for PEAP with TLS
1.3.

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

src/eap_peer/eap_peap.c

@@ -1085,7 +1085,11 @@ static struct wpabuf * eap_peap_process(struct eap_sm *sm, void *priv,
 		}
 
 		if (tls_connection_established(sm->ssl_ctx, data->ssl.conn)) {
-			char *label;
+			const char *label;
+			const u8 eap_tls13_context[1] = { EAP_TYPE_PEAP };
+			const u8 *context = NULL;
+			size_t context_len = 0;
+
 			wpa_printf(MSG_DEBUG,
 				   "EAP-PEAP: TLS done, proceed to Phase 2");
 			eap_peap_free_key(data);
@@ -1095,16 +1099,25 @@ static struct wpabuf * eap_peap_process(struct eap_sm *sm, void *priv,
 			 * PEAPv1 implementations seem to be using the old
 			 * label, "client EAP encryption", instead. Use the old
 			 * label by default, but allow it to be configured with
-			 * phase1 parameter peaplabel=1. */
-			if (data->force_new_label)
+			 * phase1 parameter peaplabel=1.
+			 *
+			 * When using TLS 1.3, draft-ietf-emu-tls-eap-types
+			 * defines a new set of label and context parameters.
+			 */
+			if (data->ssl.tls_v13) {
+				label = "EXPORTER_EAP_TLS_Key_Material";
+				context = eap_tls13_context;
+				context_len = sizeof(eap_tls13_context);
+			} else if (data->force_new_label) {
 				label = "client PEAP encryption";
-			else
+			} else {
 				label = "client EAP encryption";
+			}
 			wpa_printf(MSG_DEBUG, "EAP-PEAP: using label '%s' in "
 				   "key derivation", label);
 			data->key_data =
 				eap_peer_tls_derive_key(sm, &data->ssl, label,
-							NULL, 0,
+							context, context_len,
 							EAP_TLS_KEY_LEN +
 							EAP_EMSK_LEN);
 			if (data->key_data) {

src/eap_server/eap_server_peap.c

@@ -325,13 +325,27 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
 	u8 *tk;
 	u8 isk[32], imck[60];
 	int res;
+	const char *label;
+	const u8 eap_tls13_context[1] = { EAP_TYPE_PEAP };
+	const u8 *context = NULL;
+	size_t context_len = 0;
+
+	if (data->ssl.tls_v13) {
+		label = "EXPORTER_EAP_TLS_Key_Material";
+		context = eap_tls13_context;
+		context_len = sizeof(eap_tls13_context);
+	} else {
+		/* TODO: PEAPv1 - different label in some cases */
+		label = "client EAP encryption";
+	}
 
 	/*
 	 * Tunnel key (TK) is the first 60 octets of the key generated by
 	 * phase 1 of PEAP (based on TLS).
 	 */
-	tk = eap_server_tls_derive_key(sm, &data->ssl, "client EAP encryption",
-				       NULL, 0, EAP_TLS_KEY_LEN);
+	tk = eap_server_tls_derive_key(sm, &data->ssl, label,
+				       context, context_len,
+				       EAP_TLS_KEY_LEN);
 	if (tk == NULL)
 		return -1;
 	wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: TK", tk, 60);
@@ -1300,6 +1314,10 @@ static u8 * eap_peap_getKey(struct eap_sm *sm, void *priv, size_t *len)
 {
 	struct eap_peap_data *data = priv;
 	u8 *eapKeyData;
+	const char *label;
+	const u8 eap_tls13_context[1] = { EAP_TYPE_PEAP };
+	const u8 *context = NULL;
+	size_t context_len = 0;
 
 	if (data->state != SUCCESS)
 		return NULL;
@@ -1332,9 +1350,17 @@ static u8 * eap_peap_getKey(struct eap_sm *sm, void *priv, size_t *len)
 		return eapKeyData;
 	}
 
-	/* TODO: PEAPv1 - different label in some cases */
+	if (data->ssl.tls_v13) {
+		label = "EXPORTER_EAP_TLS_Key_Material";
+		context = eap_tls13_context;
+		context_len = sizeof(eap_tls13_context);
+	} else {
+		/* TODO: PEAPv1 - different label in some cases */
+		label = "client EAP encryption";
+	}
+
 	eapKeyData = eap_server_tls_derive_key(sm, &data->ssl,
-					       "client EAP encryption", NULL, 0,
+					       label, context, context_len,
 					       EAP_TLS_KEY_LEN + EAP_EMSK_LEN);
 	if (eapKeyData) {
 		os_memset(eapKeyData + EAP_TLS_KEY_LEN, 0, EAP_EMSK_LEN);
@@ -1353,6 +1379,10 @@ static u8 * eap_peap_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 {
 	struct eap_peap_data *data = priv;
 	u8 *eapKeyData, *emsk;
+	const char *label;
+	const u8 eap_tls13_context[1] = { EAP_TYPE_PEAP };
+	const u8 *context = NULL;
+	size_t context_len = 0;
 
 	if (data->state != SUCCESS)
 		return NULL;
@@ -1362,9 +1392,17 @@ static u8 * eap_peap_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 		return NULL;
 	}
 
-	/* TODO: PEAPv1 - different label in some cases */
+	if (data->ssl.tls_v13) {
+		label = "EXPORTER_EAP_TLS_Key_Material";
+		context = eap_tls13_context;
+		context_len = sizeof(eap_tls13_context);
+	} else {
+		/* TODO: PEAPv1 - different label in some cases */
+		label = "client EAP encryption";
+	}
+
 	eapKeyData = eap_server_tls_derive_key(sm, &data->ssl,
-					       "client EAP encryption", NULL, 0,
+					       label, context, context_len,
 					       EAP_TLS_KEY_LEN + EAP_EMSK_LEN);
 	if (eapKeyData) {
 		emsk = os_memdup(eapKeyData + EAP_TLS_KEY_LEN, EAP_EMSK_LEN);