772 lines
24 KiB
C
772 lines
24 KiB
C
/*
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* TLS 1.3 client-side functions
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of mbed TLS ( https://tls.mbed.org )
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*/
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#include "common.h"
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#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
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#if defined(MBEDTLS_SSL_CLI_C)
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#include <string.h>
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#include "mbedtls/debug.h"
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#include "mbedtls/error.h"
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#include "ssl_misc.h"
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#include "ecdh_misc.h"
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#define CLIENT_HELLO_RANDOM_LEN 32
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/* Write extensions */
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/*
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* ssl_tls13_write_supported_versions_ext():
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*
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* struct {
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* ProtocolVersion versions<2..254>;
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* } SupportedVersions;
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*/
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static int ssl_tls13_write_supported_versions_ext( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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unsigned char *p = buf;
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*olen = 0;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported versions extension" ) );
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/* Check if we have space to write the extension:
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* - extension_type (2 bytes)
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* - extension_data_length (2 bytes)
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* - versions_length (1 byte )
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* - versions (2 bytes)
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*/
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MBEDTLS_SSL_CHK_BUF_PTR( p, end, 7 );
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/* Write extension_type */
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MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS, p, 0 );
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/* Write extension_data_length */
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MBEDTLS_PUT_UINT16_BE( 3, p, 2 );
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p += 4;
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/* Length of versions */
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*p++ = 0x2;
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/* Write values of supported versions.
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*
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* They are defined by the configuration.
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*
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* Currently, only one version is advertised.
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*/
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mbedtls_ssl_write_version( ssl->conf->max_major_ver,
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ssl->conf->max_minor_ver,
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ssl->conf->transport, p );
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "supported version: [%d:%d]",
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ssl->conf->max_major_ver,
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ssl->conf->max_minor_ver ) );
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*olen = 7;
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return( 0 );
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}
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#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
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/*
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* Functions for writing supported_groups extension.
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*
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* Stucture of supported_groups:
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* enum {
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* secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
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* x25519(0x001D), x448(0x001E),
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* ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
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* ffdhe6144(0x0103), ffdhe8192(0x0104),
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* ffdhe_private_use(0x01FC..0x01FF),
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* ecdhe_private_use(0xFE00..0xFEFF),
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* (0xFFFF)
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* } NamedGroup;
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* struct {
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* NamedGroup named_group_list<2..2^16-1>;
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* } NamedGroupList;
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*/
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#if defined(MBEDTLS_ECDH_C)
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/*
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* In versions of TLS prior to TLS 1.3, this extension was named
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* 'elliptic_curves' and only contained elliptic curve groups.
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*/
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static int ssl_tls13_write_named_group_list_ecdhe( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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unsigned char *p = buf;
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*olen = 0;
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if( ssl->conf->curve_list == NULL )
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return( MBEDTLS_ERR_SSL_BAD_CONFIG );
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for ( const mbedtls_ecp_group_id *grp_id = ssl->conf->curve_list;
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*grp_id != MBEDTLS_ECP_DP_NONE;
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grp_id++ )
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{
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const mbedtls_ecp_curve_info *info;
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info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
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if( info == NULL )
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continue;
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if( !mbedtls_ssl_tls13_named_group_is_ecdhe( info->tls_id ) )
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continue;
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MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2);
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MBEDTLS_PUT_UINT16_BE( info->tls_id, p, 0 );
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p += 2;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
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mbedtls_ecp_curve_info_from_tls_id( info->tls_id )->name,
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info->tls_id ) );
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}
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*olen = p - buf;
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return( 0 );
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}
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#else
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static int ssl_tls13_write_named_group_list_ecdhe( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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((void) ssl);
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((void) buf);
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((void) end);
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*olen = 0;
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return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
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}
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#endif /* MBEDTLS_ECDH_C */
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static int ssl_tls13_write_named_group_list_dhe( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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((void) ssl);
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((void) buf);
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((void) end);
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*olen = 0;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "write_named_group_dhe is not implemented" ) );
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return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
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}
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static int ssl_tls13_write_supported_groups_ext( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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unsigned char *p = buf ;
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unsigned char *named_group_list_ptr; /* Start of named_group_list */
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size_t named_group_list_len; /* Length of named_group_list */
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size_t output_len = 0;
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int ret_ecdhe, ret_dhe;
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*olen = 0;
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if( !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
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return( 0 );
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_groups extension" ) );
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/* Check if we have space for header and length fields:
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* - extension_type (2 bytes)
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* - extension_data_length (2 bytes)
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* - named_group_list_length (2 bytes)
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*/
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MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
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p += 6;
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named_group_list_ptr = p;
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ret_ecdhe = ssl_tls13_write_named_group_list_ecdhe( ssl, p, end, &output_len );
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if( ret_ecdhe != 0 )
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{
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MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_named_group_list_ecdhe", ret_ecdhe );
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}
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p += output_len;
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ret_dhe = ssl_tls13_write_named_group_list_dhe( ssl, p, end, &output_len );
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if( ret_dhe != 0 )
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{
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MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_named_group_list_dhe", ret_dhe );
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}
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p += output_len;
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/* Both ECDHE and DHE failed. */
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if( ret_ecdhe != 0 && ret_dhe != 0 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "Both ECDHE and DHE groups are fail. " ) );
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
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}
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/* Length of named_group_list*/
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named_group_list_len = p - named_group_list_ptr;
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if( named_group_list_len == 0 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "No group available." ) );
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
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}
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/* Write extension_type */
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MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_GROUPS, buf, 0 );
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/* Write extension_data_length */
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MBEDTLS_PUT_UINT16_BE( named_group_list_len + 2, buf, 2 );
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/* Write length of named_group_list */
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MBEDTLS_PUT_UINT16_BE( named_group_list_len, buf, 4 );
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MBEDTLS_SSL_DEBUG_BUF( 3, "Supported groups extension", buf + 4, named_group_list_len + 2 );
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*olen = p - buf;
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ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_GROUPS;
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return( 0 );
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}
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/*
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* Functions for writing key_share extension.
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*/
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#if defined(MBEDTLS_ECDH_C)
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static int ssl_tls13_generate_and_write_ecdh_key_exchange(
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mbedtls_ssl_context *ssl,
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uint16_t named_group,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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const mbedtls_ecp_curve_info *curve_info =
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mbedtls_ecp_curve_info_from_tls_id( named_group );
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if( curve_info == NULL )
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "offer curve %s", curve_info->name ) );
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if( ( ret = mbedtls_ecdh_setup_no_everest( &ssl->handshake->ecdh_ctx,
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curve_info->grp_id ) ) != 0 )
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{
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MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_setup_no_everest", ret );
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return( ret );
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}
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ret = mbedtls_ecdh_tls13_make_params( &ssl->handshake->ecdh_ctx, olen,
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buf, end - buf,
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ssl->conf->f_rng, ssl->conf->p_rng );
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if( ret != 0 )
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{
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MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_tls13_make_params", ret );
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return( ret );
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}
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MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
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MBEDTLS_DEBUG_ECDH_Q );
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return( 0 );
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}
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#endif /* MBEDTLS_ECDH_C */
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static int ssl_tls13_get_default_group_id( mbedtls_ssl_context *ssl,
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uint16_t *group_id )
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{
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int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
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#if defined(MBEDTLS_ECDH_C)
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/* Pick first available ECDHE group compatible with TLS 1.3 */
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if( ssl->conf->curve_list == NULL )
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return( MBEDTLS_ERR_SSL_BAD_CONFIG );
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for ( const mbedtls_ecp_group_id *grp_id = ssl->conf->curve_list;
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*grp_id != MBEDTLS_ECP_DP_NONE;
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grp_id++ )
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{
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const mbedtls_ecp_curve_info *info;
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info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
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if( info != NULL &&
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mbedtls_ssl_tls13_named_group_is_ecdhe( info->tls_id ) )
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{
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*group_id = info->tls_id;
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return( 0 );
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}
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}
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#else
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((void) ssl);
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((void) group_id);
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#endif /* MBEDTLS_ECDH_C */
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/*
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* Add DHE named groups here.
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* Pick first available DHE group compatible with TLS 1.3
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*/
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return( ret );
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}
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/*
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* ssl_tls13_write_key_share_ext
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*
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* Structure of key_share extension in ClientHello:
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*
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* struct {
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* NamedGroup group;
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* opaque key_exchange<1..2^16-1>;
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* } KeyShareEntry;
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* struct {
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* KeyShareEntry client_shares<0..2^16-1>;
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* } KeyShareClientHello;
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*/
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static int ssl_tls13_write_key_share_ext( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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unsigned char *p = buf;
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unsigned char *client_shares_ptr; /* Start of client_shares */
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size_t client_shares_len; /* Length of client_shares */
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uint16_t group_id;
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int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
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*olen = 0;
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if( !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
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return( 0 );
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/* Check if we have space for header and length fields:
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* - extension_type (2 bytes)
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* - extension_data_length (2 bytes)
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* - client_shares_length (2 bytes)
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*/
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MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
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p += 6;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello: adding key share extension" ) );
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/* HRR could already have requested something else. */
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group_id = ssl->handshake->offered_group_id;
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if( !mbedtls_ssl_tls13_named_group_is_ecdhe( group_id ) &&
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!mbedtls_ssl_tls13_named_group_is_dhe( group_id ) )
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{
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MBEDTLS_SSL_PROC_CHK( ssl_tls13_get_default_group_id( ssl,
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&group_id ) );
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}
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/*
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* Dispatch to type-specific key generation function.
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*
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* So far, we're only supporting ECDHE. With the introduction
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* of PQC KEMs, we'll want to have multiple branches, one per
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* type of KEM, and dispatch to the corresponding crypto. And
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* only one key share entry is allowed.
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*/
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client_shares_ptr = p;
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#if defined(MBEDTLS_ECDH_C)
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if( mbedtls_ssl_tls13_named_group_is_ecdhe( group_id ) )
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{
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/* Pointer to group */
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unsigned char *group_ptr = p;
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/* Length of key_exchange */
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size_t key_exchange_len;
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/* Check there is space for header of KeyShareEntry
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* - group (2 bytes)
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* - key_exchange_length (2 bytes)
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*/
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MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 );
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p += 4;
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ret = ssl_tls13_generate_and_write_ecdh_key_exchange( ssl, group_id,
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p, end,
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&key_exchange_len );
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p += key_exchange_len;
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if( ret != 0 )
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return( ret );
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/* Write group */
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MBEDTLS_PUT_UINT16_BE( group_id, group_ptr, 0 );
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/* Write key_exchange_length */
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MBEDTLS_PUT_UINT16_BE( key_exchange_len, group_ptr, 2 );
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}
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else
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#endif /* MBEDTLS_ECDH_C */
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if( 0 /* other KEMs? */ )
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{
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/* Do something */
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}
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else
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
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/* Length of client_shares */
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client_shares_len = p - client_shares_ptr;
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if( client_shares_len == 0)
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "No key share defined." ) );
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
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}
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/* Write extension_type */
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MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_KEY_SHARE, buf, 0 );
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/* Write extension_data_length */
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MBEDTLS_PUT_UINT16_BE( client_shares_len + 2, buf, 2 );
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/* Write client_shares_length */
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MBEDTLS_PUT_UINT16_BE( client_shares_len, buf, 4 );
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/* Update offered_group_id field */
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ssl->handshake->offered_group_id = group_id;
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/* Output the total length of key_share extension. */
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*olen = p - buf;
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MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, key_share extension", buf, *olen );
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ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_KEY_SHARE;
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cleanup:
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return( ret );
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}
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#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
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/* Write cipher_suites
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* CipherSuite cipher_suites<2..2^16-2>;
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*/
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static int ssl_tls13_write_client_hello_cipher_suites(
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mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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unsigned char *p = buf;
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const int *ciphersuite_list;
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unsigned char *cipher_suites_ptr; /* Start of the cipher_suites list */
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size_t cipher_suites_len;
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*olen = 0 ;
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/*
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* Ciphersuite list
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*
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* This is a list of the symmetric cipher options supported by
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* the client, specifically the record protection algorithm
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* ( including secret key length ) and a hash to be used with
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* HKDF, in descending order of client preference.
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*/
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ciphersuite_list = ssl->conf->ciphersuite_list;
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/* Check there is space for the cipher suite list length (2 bytes). */
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MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
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p += 2;
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/* Write cipher_suites */
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cipher_suites_ptr = p;
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for ( size_t i = 0; ciphersuite_list[i] != 0; i++ )
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{
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int cipher_suite = ciphersuite_list[i];
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const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
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ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( cipher_suite );
|
|
if( ciphersuite_info == NULL )
|
|
continue;
|
|
if( !( MBEDTLS_SSL_MINOR_VERSION_4 >= ciphersuite_info->min_minor_ver &&
|
|
MBEDTLS_SSL_MINOR_VERSION_4 <= ciphersuite_info->max_minor_ver ) )
|
|
continue;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %04x, %s",
|
|
(unsigned int) cipher_suite,
|
|
ciphersuite_info->name ) );
|
|
|
|
/* Check there is space for the cipher suite identifier (2 bytes). */
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
|
|
MBEDTLS_PUT_UINT16_BE( cipher_suite, p, 0 );
|
|
p += 2;
|
|
}
|
|
|
|
/* Write the cipher_suites length in number of bytes */
|
|
cipher_suites_len = p - cipher_suites_ptr;
|
|
MBEDTLS_PUT_UINT16_BE( cipher_suites_len, buf, 0 );
|
|
MBEDTLS_SSL_DEBUG_MSG( 3,
|
|
( "client hello, got %" MBEDTLS_PRINTF_SIZET " cipher suites",
|
|
cipher_suites_len/2 ) );
|
|
|
|
/* Output the total length of cipher_suites field. */
|
|
*olen = p - buf;
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Structure of ClientHello message:
|
|
*
|
|
* struct {
|
|
* ProtocolVersion legacy_version = 0x0303; // TLS v1.2
|
|
* Random random;
|
|
* opaque legacy_session_id<0..32>;
|
|
* CipherSuite cipher_suites<2..2^16-2>;
|
|
* opaque legacy_compression_methods<1..2^8-1>;
|
|
* Extension extensions<8..2^16-1>;
|
|
* } ClientHello;
|
|
*/
|
|
static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
|
|
unsigned char *buf,
|
|
unsigned char *end,
|
|
size_t *olen )
|
|
{
|
|
|
|
int ret;
|
|
unsigned char *extensions_len_ptr; /* Pointer to extensions length */
|
|
size_t output_len; /* Length of buffer used by function */
|
|
size_t extensions_len; /* Length of the list of extensions*/
|
|
|
|
/* Buffer management */
|
|
unsigned char *p = buf;
|
|
|
|
*olen = 0;
|
|
|
|
/* No validation needed here. It has been done by ssl_conf_check() */
|
|
ssl->major_ver = ssl->conf->min_major_ver;
|
|
ssl->minor_ver = ssl->conf->min_minor_ver;
|
|
|
|
/*
|
|
* Write legacy_version
|
|
* ProtocolVersion legacy_version = 0x0303; // TLS v1.2
|
|
*
|
|
* For TLS 1.3 we use the legacy version number {0x03, 0x03}
|
|
* instead of the true version number.
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
|
|
MBEDTLS_PUT_UINT16_BE( 0x0303, p, 0 );
|
|
p += 2;
|
|
|
|
/* Write the random bytes ( random ).*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, CLIENT_HELLO_RANDOM_LEN );
|
|
memcpy( p, ssl->handshake->randbytes, CLIENT_HELLO_RANDOM_LEN );
|
|
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes",
|
|
p, CLIENT_HELLO_RANDOM_LEN );
|
|
p += CLIENT_HELLO_RANDOM_LEN;
|
|
|
|
/*
|
|
* Write legacy_session_id
|
|
*
|
|
* Versions of TLS before TLS 1.3 supported a "session resumption" feature
|
|
* which has been merged with pre-shared keys in this version. A client
|
|
* which has a cached session ID set by a pre-TLS 1.3 server SHOULD set
|
|
* this field to that value. In compatibility mode, this field MUST be
|
|
* non-empty, so a client not offering a pre-TLS 1.3 session MUST generate
|
|
* a new 32-byte value. This value need not be random but SHOULD be
|
|
* unpredictable to avoid implementations fixating on a specific value
|
|
* ( also known as ossification ). Otherwise, it MUST be set as a zero-length
|
|
* vector ( i.e., a zero-valued single byte length field ).
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 );
|
|
*p++ = 0; /* session id length set to zero */
|
|
|
|
/* Write cipher_suites */
|
|
ret = ssl_tls13_write_client_hello_cipher_suites( ssl, p, end, &output_len );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
p += output_len;
|
|
|
|
/* Write legacy_compression_methods
|
|
*
|
|
* For every TLS 1.3 ClientHello, this vector MUST contain exactly
|
|
* one byte set to zero, which corresponds to the 'null' compression
|
|
* method in prior versions of TLS.
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
|
|
*p++ = 1;
|
|
*p++ = MBEDTLS_SSL_COMPRESS_NULL;
|
|
|
|
/* Write extensions */
|
|
|
|
/* Keeping track of the included extensions */
|
|
ssl->handshake->extensions_present = MBEDTLS_SSL_EXT_NONE;
|
|
|
|
/* First write extensions, then the total length */
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
|
|
extensions_len_ptr = p;
|
|
p += 2;
|
|
|
|
/* Write supported_versions extension
|
|
*
|
|
* Supported Versions Extension is mandatory with TLS 1.3.
|
|
*/
|
|
ret = ssl_tls13_write_supported_versions_ext( ssl, p, end, &output_len );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
p += output_len;
|
|
|
|
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
|
|
/* Write supported_groups extension
|
|
*
|
|
* It is REQUIRED for ECDHE cipher_suites.
|
|
*/
|
|
ret = ssl_tls13_write_supported_groups_ext( ssl, p, end, &output_len );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
p += output_len;
|
|
|
|
/* Write key_share extension
|
|
*
|
|
* We need to send the key shares under three conditions:
|
|
* 1) A certificate-based ciphersuite is being offered. In this case
|
|
* supported_groups and supported_signature extensions have been
|
|
* successfully added.
|
|
* 2) A PSK-based ciphersuite with ECDHE is offered. In this case the
|
|
* psk_key_exchange_modes has been added as the last extension.
|
|
* 3) Or, in case all ciphers are supported ( which includes #1 and #2
|
|
* from above )
|
|
*/
|
|
ret = ssl_tls13_write_key_share_ext( ssl, p, end, &output_len );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
p += output_len;
|
|
|
|
/* Write signature_algorithms extension
|
|
*
|
|
* It is REQUIRED for certificate authenticated cipher_suites.
|
|
*/
|
|
ret = mbedtls_ssl_tls13_write_sig_alg_ext( ssl, p, end, &output_len );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
p += output_len;
|
|
|
|
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
|
|
|
|
/* Add more extensions here */
|
|
|
|
/* Write the length of the list of extensions. */
|
|
extensions_len = p - extensions_len_ptr - 2;
|
|
MBEDTLS_PUT_UINT16_BE( extensions_len, extensions_len_ptr, 0 );
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, total extension length: %" MBEDTLS_PRINTF_SIZET ,
|
|
extensions_len ) );
|
|
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", extensions_len_ptr, extensions_len );
|
|
|
|
*olen = p - buf;
|
|
return( 0 );
|
|
}
|
|
|
|
static int ssl_tls13_finalize_client_hello( mbedtls_ssl_context *ssl )
|
|
{
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_HELLO );
|
|
return( 0 );
|
|
}
|
|
|
|
static int ssl_tls13_prepare_client_hello( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret;
|
|
|
|
if( ssl->conf->f_rng == NULL )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided" ) );
|
|
return( MBEDTLS_ERR_SSL_NO_RNG );
|
|
}
|
|
|
|
if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng,
|
|
ssl->handshake->randbytes,
|
|
CLIENT_HELLO_RANDOM_LEN ) ) != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1, "f_rng", ret );
|
|
return( ret );
|
|
}
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Write ClientHello handshake message.
|
|
*/
|
|
static int ssl_tls13_write_client_hello( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = 0;
|
|
unsigned char *buf;
|
|
size_t buf_len, msg_len;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write client hello" ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_prepare_client_hello( ssl ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_start_handshake_msg(
|
|
ssl, MBEDTLS_SSL_HS_CLIENT_HELLO,
|
|
&buf, &buf_len ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_client_hello_body( ssl, buf,
|
|
buf + buf_len,
|
|
&msg_len ) );
|
|
|
|
mbedtls_ssl_tls13_add_hs_hdr_to_checksum( ssl,
|
|
MBEDTLS_SSL_HS_CLIENT_HELLO,
|
|
msg_len );
|
|
ssl->handshake->update_checksum( ssl, buf, msg_len );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_finalize_client_hello( ssl ) );
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_finish_handshake_msg( ssl,
|
|
buf_len,
|
|
msg_len ) );
|
|
|
|
cleanup:
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write client hello" ) );
|
|
return ret;
|
|
}
|
|
|
|
int mbedtls_ssl_tls13_handshake_client_step( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = 0;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "client state: %d", ssl->state ) );
|
|
|
|
switch( ssl->state )
|
|
{
|
|
/*
|
|
* ssl->state is initialized as HELLO_REQUEST. It is the same
|
|
* as CLIENT_HELLO state.
|
|
*/
|
|
case MBEDTLS_SSL_HELLO_REQUEST:
|
|
case MBEDTLS_SSL_CLIENT_HELLO:
|
|
ret = ssl_tls13_write_client_hello( ssl );
|
|
break;
|
|
|
|
case MBEDTLS_SSL_SERVER_HELLO:
|
|
// Stop here : we haven't finished whole flow
|
|
ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS );
|
|
break;
|
|
|
|
default:
|
|
MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
|
|
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
|
|
}
|
|
|
|
return( ret );
|
|
}
|
|
|
|
#endif /* MBEDTLS_SSL_CLI_C */
|
|
|
|
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
|