WIP:DTLS1_3: Enecryption Implementation

5 files changed, 59 insertions, 38 deletions

diff --git a/lib/cipher.c b/lib/cipher.c
index 9f06c7ccf9..71ea578ee0 100644
--- a/lib/cipher.c
+++ b/lib/cipher.c
@@ -68,7 +68,7 @@ decrypt_packet_tls13(gnutls_session_t session,
 
 static int
 encrypt_packet_tls13(gnutls_session_t session,
-		     uint8_t *cipher_data, size_t cipher_size,
+		     mbuffer_st *bufel,
 		     gnutls_datum_t *plain,
 		     size_t pad_size,
 		     uint8_t type,
@@ -100,11 +100,8 @@ _gnutls_encrypt(gnutls_session_t session,
 		/* it fills the header, as it is included in the authenticated
 		 * data of the AEAD cipher. */
 		ret =
-		    encrypt_packet_tls13(session,
-					 _mbuffer_get_udata_ptr(bufel),
-					 _mbuffer_get_udata_size(bufel),
-					 &plaintext, min_pad, type,
-					 params);
+		    encrypt_packet_tls13(session, bufel, &plaintext,
+				    	 min_pad, type, params);
 		if (ret < 0)
 			return gnutls_assert_val(ret);
 	} else {
@@ -432,13 +429,15 @@ encrypt_packet(gnutls_session_t session,
 
 static int
 encrypt_packet_tls13(gnutls_session_t session,
-		     uint8_t *cipher_data, size_t cipher_size,
+		     mbuffer_st *bufel,
 		     gnutls_datum_t *plain,
 		     size_t pad_size,
 		     uint8_t type,
 		     record_parameters_st *params)
 {
 	int ret;
+	uint8_t *cipher_data = _mbuffer_get_udata_ptr(bufel);
+	size_t cipher_size = _mbuffer_get_udata_size(bufel);
 	unsigned int tag_size = params->write.aead_tag_size;
 	const version_entry_st *ver = get_version(session);
 	uint8_t nonce[MAX_CIPHER_IV_SIZE];
@@ -488,10 +487,17 @@ encrypt_packet_tls13(gnutls_session_t session,
 	}
 
 	/* create authenticated data header */
-	aad[0] = GNUTLS_APPLICATION_DATA;
-	aad[1] = 0x03;
-	aad[2] = 0x03;
-	_gnutls_write_uint16(total+tag_size, &aad[3]);
+	if (session->internals.transport == GNUTLS_STREAM) {
+		aad[0] = GNUTLS_APPLICATION_DATA;
+		aad[1] = 0x03;
+		aad[2] = 0x03;
+		_gnutls_write_uint16(total+tag_size, &aad[3]);
+	} else {
+		/* DTLS1.3 uses header as as (AE)AD */
+		uint8_t *header = _mbuffer_get_uhead_ptr(bufel);
+		_gnutls_write_uint16(total+tag_size, &header[3]); // Set length
+		memcpy(aad, header, 5);
+	}
 
 	auth_iov[0].iov_base = aad;
 	auth_iov[0].iov_len = sizeof(aad);
diff --git a/lib/constate.c b/lib/constate.c
index 0abe561507..998b590af6 100644
--- a/lib/constate.c
+++ b/lib/constate.c
@@ -1338,6 +1338,7 @@ _tls13_init_record_state(gnutls_cipher_algorithm_t algo, record_state_st *state)
 
 	state->aead_tag_size = gnutls_cipher_get_tag_size(algo);
 	state->is_aead = 1;
+	state->sequence_number = 0;
 
 	return 0;
 }
diff --git a/lib/dtls.c b/lib/dtls.c
index 002c7145ef..f5b4a0a4c9 100644
--- a/lib/dtls.c
+++ b/lib/dtls.c
@@ -586,7 +586,10 @@ size_t gnutls_est_record_overhead_size(gnutls_protocol_t version,
 	if (v->transport == GNUTLS_STREAM)
 		total = TLS_RECORD_HEADER_SIZE;
 	else
-		total = DTLS_RECORD_HEADER_SIZE;
+		if (cipher == GNUTLS_CIPHER_NULL)
+			total = DTLS_RECORD_HEADER_SIZE;
+		else
+			total = DTLS13_RECORD_HEADER_SIZE;
 
 	total += _gnutls_record_overhead(v, c, m, 1);
 
@@ -629,14 +632,8 @@ static int record_overhead_rt(gnutls_session_t session)
  **/
 size_t gnutls_record_overhead_size(gnutls_session_t session)
 {
-	const version_entry_st *v = get_version(session);
 	int ret;
-	size_t total;
-
-	if (v->transport == GNUTLS_STREAM)
-		total = TLS_RECORD_HEADER_SIZE;
-	else
-		total = DTLS_RECORD_HEADER_SIZE;
+	size_t total = RECORD_HEADER_SIZE(session);
 
 	ret = record_overhead_rt(session);
 	if (ret >= 0)
@@ -667,13 +664,20 @@ unsigned int gnutls_dtls_get_data_mtu(gnutls_session_t session)
 
 	mtu -= RECORD_HEADER_SIZE(session);
 
-	if (session->internals.initial_negotiation_completed == 0)
-		return mtu;
-
 	ret = _gnutls_epoch_get(session, EPOCH_WRITE_CURRENT, &params);
 	if (ret < 0)
 		return mtu;
 
+	if (session->internals.initial_negotiation_completed == 0){
+		if (session->security_parameters.pversion->tls13_sem)
+			return (mtu - params->write.aead_tag_size - 1); //Tag + content_type
+		return mtu;
+	}
+
+	if (session->security_parameters.pversion->tls13_sem &&
+			params->cipher->id != GNUTLS_CIPHER_NULL)
+		mtu -= params->write.aead_tag_size + 1; //Tag + content_type
+
 	if (params->cipher->type == CIPHER_AEAD || params->cipher->type == CIPHER_STREAM)
 		return mtu-_gnutls_record_overhead(get_version(session), params->cipher, params->mac, 0);
 
diff --git a/lib/gnutls_int.h b/lib/gnutls_int.h
index 0a2d21256a..aa7c9f7f1d 100644
--- a/lib/gnutls_int.h
+++ b/lib/gnutls_int.h
@@ -185,9 +185,12 @@ typedef enum record_send_state_t {
 #define DEFAULT_MAX_RECORD_SIZE 16384
 #define DEFAULT_MAX_EARLY_DATA_SIZE 16384
 #define TLS_RECORD_HEADER_SIZE 5
-#define DTLS_RECORD_HEADER_SIZE (TLS_RECORD_HEADER_SIZE+8)
-#define RECORD_HEADER_SIZE(session) (IS_DTLS(session) ? DTLS_RECORD_HEADER_SIZE : TLS_RECORD_HEADER_SIZE)
-#define MAX_RECORD_HEADER_SIZE DTLS_RECORD_HEADER_SIZE
+#define DTLS13_RECORD_HEADER_SIZE 5 //Will be made dynamic
+#define DTLS_RECORD_HEADER_SIZE TLS_RECORD_HEADER_SIZE+8
+#define DTLS_RESOLVE_RECORD_HEADER_SIZE(session) (session->security_parameters.pversion->tls13_sem && session->security_parameters.epoch_write>1) ? DTLS13_RECORD_HEADER_SIZE : DTLS_RECORD_HEADER_SIZE
+	
+#define RECORD_HEADER_SIZE(session) (IS_DTLS(session) ? DTLS_RESOLVE_RECORD_HEADER_SIZE(session) : TLS_RECORD_HEADER_SIZE)
+#define MAX_RECORD_HEADER_SIZE TLS_RECORD_HEADER_SIZE+8
 
 #define MIN_RECORD_SIZE 512
 #define MIN_RECORD_SIZE_SMALL 64
diff --git a/lib/record.c b/lib/record.c
index 6b9ed8c9e3..5a733d5915 100644
--- a/lib/record.c
+++ b/lib/record.c
@@ -538,20 +538,27 @@ _gnutls_send_tlen_int(gnutls_session_t session, content_type_t type,
 			return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
 
 		headers = _mbuffer_get_uhead_ptr(bufel);
-		if (vers->tls13_sem && record_params->cipher->id != GNUTLS_CIPHER_NULL)
-			headers[0] = GNUTLS_APPLICATION_DATA;
-		else
-			headers[0] = type;
-
-		/* Use the default record version, if it is
-		 * set. */
-		ret = copy_record_version(session, htype, &headers[1]);
-		if (ret < 0)
-			return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+		if (vers->id == GNUTLS_DTLS1_3 && record_params->cipher->id != GNUTLS_CIPHER_NULL) {
+			/* Currently constant will change for dynamic length and CID */
+			headers[0] = 0x2c | (record_params->epoch & 0x0003);
+			_gnutls_write_uint16(record_state->sequence_number, &headers[1]);
+			//size is determined in encrypt_packet_tls13()
+		} else {
+			if (vers->tls13_sem && record_params->cipher->id != GNUTLS_CIPHER_NULL)
+				headers[0] = GNUTLS_APPLICATION_DATA;
+			else
+				headers[0] = type;
+
+			/* Use the default record version, if it is
+			 * set. */
+			ret = copy_record_version(session, htype, &headers[1]);
+			if (ret < 0)
+				return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
 
-		/* Adjust header length and add sequence for DTLS */
-		if (IS_DTLS(session))
-			_gnutls_write_uint64(record_state->sequence_number, &headers[3]);
+			/* Adjust header length and add sequence for DTLS */
+			if (IS_DTLS(session))
+				_gnutls_write_uint64(record_state->sequence_number, &headers[3]);
+		}
 
 		_gnutls_record_log
 		    ("REC[%p]: Preparing Packet %s(%d) with length: %d and min pad: %d\n",