/*
* TLS 1.3 functionality shared between client and server
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "common.h"
#if defined(MBEDTLS_SSL_TLS_C)
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
#include "mbedtls/error.h"
#include "mbedtls/debug.h"
#include "ssl_misc.h"
int mbedtls_ssl_tls1_3_fetch_handshake_msg( mbedtls_ssl_context *ssl,
unsigned hs_type,
unsigned char **buf,
size_t *buflen )
{
int ret;
if( ( ret = mbedtls_ssl_read_record( ssl, 0 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
goto cleanup;
}
if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
ssl->in_msg[0] != hs_type )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Receive unexpected handshake message." ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE,
MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
ret = MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
goto cleanup;
}
/*
* Jump handshake header (4 bytes, see Section 4 of RFC 8446).
* ...
* HandshakeType msg_type;
* uint24 length;
* ...
*/
*buf = ssl->in_msg + 4;
*buflen = ssl->in_hslen - 4;
cleanup:
return( ret );
}
int mbedtls_ssl_tls13_start_handshake_msg( mbedtls_ssl_context *ssl,
unsigned hs_type,
unsigned char **buf,
size_t *buf_len )
{
/*
* Reserve 4 bytes for hanshake header. ( Section 4,RFC 8446 )
* ...
* HandshakeType msg_type;
* uint24 length;
* ...
*/
*buf = ssl->out_msg + 4;
*buf_len = MBEDTLS_SSL_OUT_CONTENT_LEN - 4;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = hs_type;
return( 0 );
}
int mbedtls_ssl_tls13_finish_handshake_msg( mbedtls_ssl_context *ssl,
size_t buf_len,
size_t msg_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t msg_len_with_header;
((void) buf_len);
/* Add reserved 4 bytes for handshake header */
msg_len_with_header = msg_len + 4;
ssl->out_msglen = msg_len_with_header;
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_write_handshake_msg_ext( ssl, 0 ) );
cleanup:
return( ret );
}
void mbedtls_ssl_tls1_3_add_hs_msg_to_checksum( mbedtls_ssl_context *ssl,
unsigned hs_type,
unsigned char const *msg,
size_t msg_len )
{
mbedtls_ssl_tls13_add_hs_hdr_to_checksum( ssl, hs_type, msg_len );
ssl->handshake->update_checksum( ssl, msg, msg_len );
}
void mbedtls_ssl_tls13_add_hs_hdr_to_checksum( mbedtls_ssl_context *ssl,
unsigned hs_type,
size_t total_hs_len )
{
unsigned char hs_hdr[4];
/* Build HS header for checksum update. */
hs_hdr[0] = MBEDTLS_BYTE_0( hs_type );
hs_hdr[1] = MBEDTLS_BYTE_2( total_hs_len );
hs_hdr[2] = MBEDTLS_BYTE_1( total_hs_len );
hs_hdr[3] = MBEDTLS_BYTE_0( total_hs_len );
ssl->handshake->update_checksum( ssl, hs_hdr, sizeof( hs_hdr ) );
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/*
* mbedtls_ssl_tls13_write_sig_alg_ext( )
*
* enum {
* ....
* ecdsa_secp256r1_sha256( 0x0403 ),
* ecdsa_secp384r1_sha384( 0x0503 ),
* ecdsa_secp521r1_sha512( 0x0603 ),
* ....
* } SignatureScheme;
*
* struct {
* SignatureScheme supported_signature_algorithms<2..2^16-2>;
* } SignatureSchemeList;
*
* Only if we handle at least one key exchange that needs signatures.
*/
int mbedtls_ssl_tls13_write_sig_alg_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
unsigned char *p = buf;
unsigned char *supported_sig_alg_ptr; /* Start of supported_signature_algorithms */
size_t supported_sig_alg_len = 0; /* Length of supported_signature_algorithms */
*olen = 0;
/* Skip the extension on the client if all allowed key exchanges
* are PSK-based. */
#if defined(MBEDTLS_SSL_CLI_C)
if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
!mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
{
return( 0 );
}
#endif /* MBEDTLS_SSL_CLI_C */
MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding signature_algorithms extension" ) );
/* Check if we have space for header and length field:
* - extension_type (2 bytes)
* - extension_data_length (2 bytes)
* - supported_signature_algorithms_length (2 bytes)
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
p += 6;
/*
* Write supported_signature_algorithms
*/
supported_sig_alg_ptr = p;
for( const uint16_t *sig_alg = ssl->conf->tls13_sig_algs;
*sig_alg != MBEDTLS_TLS13_SIG_NONE; sig_alg++ )
{
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
MBEDTLS_PUT_UINT16_BE( *sig_alg, p, 0 );
p += 2;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "signature scheme [%x]", *sig_alg ) );
}
/* Length of supported_signature_algorithms */
supported_sig_alg_len = p - supported_sig_alg_ptr;
if( supported_sig_alg_len == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "No signature algorithms defined." ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
/* Write extension_type */
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SIG_ALG, buf, 0 );
/* Write extension_data_length */
MBEDTLS_PUT_UINT16_BE( supported_sig_alg_len + 2, buf, 2 );
/* Write length of supported_signature_algorithms */
MBEDTLS_PUT_UINT16_BE( supported_sig_alg_len, buf, 4 );
/* Output the total length of signature algorithms extension. */
*olen = p - buf;
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SIG_ALG;
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
#endif /* MBEDTLS_SSL_TLS_C */