TLS 1.3 - New revived high-level record range APItmp-ajuaristi-draft-ietf-tls-tls13-21

4 files changed, 73 insertions, 8 deletions

diff --git a/lib/includes/gnutls/gnutls.h.in b/lib/includes/gnutls/gnutls.h.in
index d14dd9e3cd..7247b4ded3 100644
--- a/lib/includes/gnutls/gnutls.h.in
+++ b/lib/includes/gnutls/gnutls.h.in
@@ -1205,6 +1205,8 @@ ssize_t gnutls_record_send(gnutls_session_t session, const void *data,
 ssize_t gnutls_record_send_range(gnutls_session_t session,
 				 const void *data, size_t data_size,
 				 const gnutls_range_st * range);
+ssize_t gnutls_tls13_record_send_padding(gnutls_session_t session,
+				         size_t min_pad);
 ssize_t gnutls_record_recv(gnutls_session_t session, void *data,
 			   size_t data_size);
 
diff --git a/lib/libgnutls.map b/lib/libgnutls.map
index 43a6b13212..853f62b722 100644
--- a/lib/libgnutls.map
+++ b/lib/libgnutls.map
@@ -814,6 +814,7 @@ GNUTLS_3_4
 	gnutls_record_can_use_length_hiding;
 	gnutls_range_split;
 	gnutls_record_send_range;
+	gnutls_tls13_record_send_padding;
 	gnutls_db_check_entry_time;
 	gnutls_handshake_set_random;
 	gnutls_record_cork;
diff --git a/lib/range.c b/lib/range.c
index 0b5655974f..4bdb65ba2c 100644
--- a/lib/range.c
+++ b/lib/range.c
@@ -26,6 +26,9 @@
 #include "constate.h"
 #include "record.h"
 
+/* TODO set this to the right value */
+#define TMP_IS_TLS_1_3(session) (1)
+
 static void
 _gnutls_set_range(gnutls_range_st * dst, const size_t low,
 		  const size_t high)
@@ -123,6 +126,8 @@ int gnutls_record_can_use_length_hiding(gnutls_session_t session)
 		return 1;
 	case CIPHER_STREAM:
 	case CIPHER_AEAD:
+		if (TMP_IS_TLS_1_3(session))
+			return 1;
 	default:
 		return 0;
 	}
@@ -304,3 +309,50 @@ gnutls_record_send_range(gnutls_session_t session, const void *data,
 
 	return sent;
 }
+
+ssize_t
+gnutls_tls13_record_send_padding(gnutls_session_t session, size_t min_pad)
+{
+	int ret;
+	size_t pad;
+	ssize_t max_frag;
+	record_parameters_st *record_params;
+
+	ret = _gnutls_epoch_get(session, EPOCH_WRITE_CURRENT,
+			&record_params);
+	if (ret < 0)
+		return gnutls_assert_val(ret);
+
+	max_frag = max_user_send_size(session, record_params);
+	ret = _gnutls_range_max_lh_pad(session, min_pad, max_frag);
+	if (ret < 0)
+		return gnutls_assert_val(ret);
+	pad = MIN(ret, min_pad);
+
+	_gnutls_record_log(
+			"RANGE (TLS 1.3): Sending empty message with %u bytes of padding\n",
+			(unsigned int) pad);
+
+	ret = _gnutls_send_tlen_int(session, GNUTLS_APPLICATION_DATA,
+			-1, EPOCH_WRITE_CURRENT,
+			NULL, 0,
+			pad,
+			MBUFFER_FLUSH);
+	while (ret == GNUTLS_E_AGAIN || ret == GNUTLS_E_INTERRUPTED) {
+		ret = _gnutls_send_tlen_int(session, GNUTLS_APPLICATION_DATA,
+				-1, EPOCH_WRITE_CURRENT,
+				NULL, 0, 0,
+				MBUFFER_FLUSH);
+	}
+
+	if (ret < 0)
+		return gnutls_assert_val(ret);
+	if (ret > 0) {
+		_gnutls_record_log(
+				"RANGE (TLS 1.3): ERROR: ret = %u, but should be zero\n",
+				ret);
+		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+	}
+
+	return pad;
+}
diff --git a/lib/record.c b/lib/record.c
index 7e455a4979..a8deb483f3 100644
--- a/lib/record.c
+++ b/lib/record.c
@@ -548,7 +548,8 @@ _gnutls_send_tlen_int(gnutls_session_t session, content_type_t type,
 	 * ok, and means to resume.
 	 */
 	if (session->internals.record_send_buffer.byte_length == 0 &&
-	    (tls_inner_plaintext.data_size == 0 && _data == NULL)) {
+	    (tls_inner_plaintext.data_size == 0 && _data == NULL) &&
+	    !TMP_IS_TLS_1_3(session, type)) {
 		gnutls_assert();
 		return GNUTLS_E_INVALID_REQUEST;
 	}
@@ -1459,6 +1460,10 @@ _gnutls_recv_in_buffers(gnutls_session_t session, content_type_t type,
 
 		data = _mbuffer_get_udata_ptr(decrypted);
 		len = _mbuffer_get_udata_size(decrypted);
+		if (len == 0)  {
+			ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
+			goto sanity_check_error;
+		}
 
 		if ((unsigned char) data[len - 1] != type) {
 			_gnutls_audit_log(session,
@@ -1469,6 +1474,11 @@ _gnutls_recv_in_buffers(gnutls_session_t session, content_type_t type,
 		}
 
 		_mbuffer_set_udata_size(decrypted, len - 1);
+		if ((len - 1) == 0) {
+			_gnutls_record_log(
+					"REC[%d]: TLS 1.3 - Got an empty message with padding only\n",
+					session);
+		}
 	}
 
 	/* Increase sequence number. We do both for TLS and DTLS, since in
@@ -1482,13 +1492,13 @@ _gnutls_recv_in_buffers(gnutls_session_t session, content_type_t type,
 		goto sanity_check_error;
 	}
 
-/* (originally for) TLS 1.0 CBC protection. 
- * Actually this code is called if we just received
- * an empty packet. An empty TLS packet is usually
- * sent to protect some vulnerabilities in the CBC mode.
- * In that case we go to the beginning and start reading
- * the next packet.
- */
+	/* (originally for) TLS 1.0 CBC protection.
+	 * Actually this code is called if we just received
+	 * an empty packet. An empty TLS packet is usually
+	 * sent to protect some vulnerabilities in the CBC mode.
+	 * In that case we go to the beginning and start reading
+	 * the next packet.
+	 */
 	if (_mbuffer_get_udata_size(decrypted) == 0) {
 		_mbuffer_xfree(&decrypted);
 		empty_fragments++;