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mbedtls/library/ssl_tls13_client.c
Jerry Yu 388bd0d53c fix various issues 
Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
2021-09-15 22:06:11 +08:00

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/*
* TLS 1.3 client-side functions
*
* 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.
*
* This file is part of mbed TLS ( https://tls.mbed.org )
*/
#include "common.h"
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
#if defined(MBEDTLS_SSL_CLI_C)
#include <string.h>
#include "mbedtls/debug.h"
#include "mbedtls/error.h"
#include "ssl_misc.h"
#include "ecdh_misc.h"
#define CLIENT_HELLO_RANDOM_LEN 32
/* Write extensions */
/*
* ssl_tls13_write_supported_versions_ext():
*
* struct {
* ProtocolVersion versions<2..254>;
* } SupportedVersions;
*/
static int ssl_tls13_write_supported_versions_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
unsigned char *p = buf;
*olen = 0;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported versions extension" ) );
/* Check if we have space to write the extension:
* - extension_type (2 bytes)
* - extension_data_length (2 bytes)
* - versions_length (1 byte )
* - versions (2 bytes)
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 7 );
/* Write extension_type */
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS, p, 0 );
/* Write extension_data_length */
MBEDTLS_PUT_UINT16_BE( 3, p, 2 );
p += 4;
/* Length of versions */
*p++ = 0x2;
/* Write values of supported versions.
*
* They are defined by the configuration.
*
* Currently, only one version is advertised.
*/
mbedtls_ssl_write_version( ssl->conf->max_major_ver,
ssl->conf->max_minor_ver,
ssl->conf->transport, p );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "supported version: [%d:%d]",
ssl->conf->max_major_ver,
ssl->conf->max_minor_ver ) );
*olen = 7;
return( 0 );
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/*
* Functions for writing supported_groups extension.
*
* Stucture of supported_groups:
* enum {
* secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
* x25519(0x001D), x448(0x001E),
* ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
* ffdhe6144(0x0103), ffdhe8192(0x0104),
* ffdhe_private_use(0x01FC..0x01FF),
* ecdhe_private_use(0xFE00..0xFEFF),
* (0xFFFF)
* } NamedGroup;
* struct {
* NamedGroup named_group_list<2..2^16-1>;
* } NamedGroupList;
*/
#if defined(MBEDTLS_ECDH_C)
/*
* In versions of TLS prior to TLS 1.3, this extension was named
* 'elliptic_curves' and only contained elliptic curve groups.
*/
static int ssl_tls13_write_named_group_list_ecdhe( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
unsigned char *p = buf;
*olen = 0;
if( ssl->conf->curve_list == NULL )
return( MBEDTLS_ERR_SSL_BAD_CONFIG );
for ( const mbedtls_ecp_group_id *grp_id = ssl->conf->curve_list;
*grp_id != MBEDTLS_ECP_DP_NONE;
grp_id++ )
{
const mbedtls_ecp_curve_info *info;
info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
if( info == NULL )
continue;
if( !mbedtls_ssl_tls13_named_group_is_ecdhe( info->tls_id ) )
continue;
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2);
MBEDTLS_PUT_UINT16_BE( info->tls_id, p, 0 );
p += 2;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "NamedGroup: %s ( %x )",
mbedtls_ecp_curve_info_from_tls_id( info->tls_id )->name,
info->tls_id ) );
}
*olen = p - buf;
return( 0 );
}
#else
static int ssl_tls13_write_named_group_list_ecdhe( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
((void) ssl);
((void) buf);
((void) end);
*olen = 0;
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_ECDH_C */
static int ssl_tls13_write_named_group_list_dhe( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
((void) ssl);
((void) buf);
((void) end);
*olen = 0;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "write_named_group_dhe is not implemented" ) );
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
static int ssl_tls13_write_supported_groups_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
unsigned char *p = buf ;
unsigned char *named_group_list_ptr; /* Start of named_group_list */
size_t named_group_list_len; /* Length of named_group_list */
size_t output_len = 0;
int ret_ecdhe, ret_dhe;
*olen = 0;
if( !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
return( 0 );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_groups extension" ) );
/* Check if we have space for header and length fields:
* - extension_type (2 bytes)
* - extension_data_length (2 bytes)
* - named_group_list_length (2 bytes)
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
p += 6;
named_group_list_ptr = p;
ret_ecdhe = ssl_tls13_write_named_group_list_ecdhe( ssl, p, end, &output_len );
if( ret_ecdhe != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_named_group_list_ecdhe", ret_ecdhe );
}
p += output_len;
ret_dhe = ssl_tls13_write_named_group_list_dhe( ssl, p, end, &output_len );
if( ret_dhe != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_named_group_list_dhe", ret_dhe );
}
p += output_len;
/* Both ECDHE and DHE failed. */
if( ret_ecdhe != 0 && ret_dhe != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Both ECDHE and DHE groups are fail. " ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
/* Length of named_group_list*/
named_group_list_len = p - named_group_list_ptr;
if( named_group_list_len == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "No group available." ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
/* Write extension_type */
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_GROUPS, buf, 0 );
/* Write extension_data_length */
MBEDTLS_PUT_UINT16_BE( named_group_list_len + 2, buf, 2 );
/* Write length of named_group_list */
MBEDTLS_PUT_UINT16_BE( named_group_list_len, buf, 4 );
MBEDTLS_SSL_DEBUG_BUF( 3, "Supported groups extension", buf + 4, named_group_list_len + 2 );
*olen = p - buf;
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_GROUPS;
return( 0 );
}
/*
* Functions for writing key_share extension.
*/
#if defined(MBEDTLS_ECDH_C)
static int ssl_tls13_generate_and_write_ecdh_key_exchange(
mbedtls_ssl_context *ssl,
uint16_t named_group,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
const mbedtls_ecp_curve_info *curve_info =
mbedtls_ecp_curve_info_from_tls_id( named_group );
if( curve_info == NULL )
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "offer curve %s", curve_info->name ) );
if( ( ret = mbedtls_ecdh_setup_no_everest( &ssl->handshake->ecdh_ctx,
curve_info->grp_id ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_setup_no_everest", ret );
return( ret );
}
ret = mbedtls_ecdh_tls13_make_params( &ssl->handshake->ecdh_ctx, olen,
buf, end - buf,
ssl->conf->f_rng, ssl->conf->p_rng );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_tls13_make_params", ret );
return( ret );
}
MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_Q );
return( 0 );
}
#endif /* MBEDTLS_ECDH_C */
static int ssl_tls13_get_default_group_id( mbedtls_ssl_context *ssl,
uint16_t *group_id )
{
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
#if defined(MBEDTLS_ECDH_C)
/* Pick first available ECDHE group compatible with TLS 1.3 */
if( ssl->conf->curve_list == NULL )
return( MBEDTLS_ERR_SSL_BAD_CONFIG );
for ( const mbedtls_ecp_group_id *grp_id = ssl->conf->curve_list;
*grp_id != MBEDTLS_ECP_DP_NONE;
grp_id++ )
{
const mbedtls_ecp_curve_info *info;
info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
if( info != NULL &&
mbedtls_ssl_tls13_named_group_is_ecdhe( info->tls_id ) )
{
*group_id = info->tls_id;
return( 0 );
}
}
#else
((void) ssl);
((void) group_id);
#endif /* MBEDTLS_ECDH_C */
/*
* Add DHE named groups here.
* Pick first available DHE group compatible with TLS 1.3
*/
return( ret );
}
/*
* ssl_tls13_write_key_share_ext
*
* Structure of key_share extension in ClientHello:
*
* struct {
* NamedGroup group;
* opaque key_exchange<1..2^16-1>;
* } KeyShareEntry;
* struct {
* KeyShareEntry client_shares<0..2^16-1>;
* } KeyShareClientHello;
*/
static int ssl_tls13_write_key_share_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
unsigned char *p = buf;
unsigned char *client_shares_ptr; /* Start of client_shares */
size_t client_shares_len; /* Length of client_shares */
uint16_t group_id;
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
*olen = 0;
if( !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
return( 0 );
/* Check if we have space for header and length fields:
* - extension_type (2 bytes)
* - extension_data_length (2 bytes)
* - client_shares_length (2 bytes)
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
p += 6;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello: adding key share extension" ) );
/* HRR could already have requested something else. */
group_id = ssl->handshake->offered_group_id;
if( !mbedtls_ssl_tls13_named_group_is_ecdhe( group_id ) &&
!mbedtls_ssl_tls13_named_group_is_dhe( group_id ) )
{
MBEDTLS_SSL_PROC_CHK( ssl_tls13_get_default_group_id( ssl,
&group_id ) );
}
/*
* Dispatch to type-specific key generation function.
*
* So far, we're only supporting ECDHE. With the introduction
* of PQC KEMs, we'll want to have multiple branches, one per
* type of KEM, and dispatch to the corresponding crypto. And
* only one key share entry is allowed.
*/
client_shares_ptr = p;
#if defined(MBEDTLS_ECDH_C)
if( mbedtls_ssl_tls13_named_group_is_ecdhe( group_id ) )
{
/* Pointer to group */
unsigned char *group_ptr = p;
/* Length of key_exchange */
size_t key_exchange_len;
/* Check there is space for header of KeyShareEntry
* - group (2 bytes)
* - key_exchange_length (2 bytes)
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 );
p += 4;
ret = ssl_tls13_generate_and_write_ecdh_key_exchange( ssl, group_id,
p, end,
&key_exchange_len );
p += key_exchange_len;
if( ret != 0 )
return( ret );
/* Write group */
MBEDTLS_PUT_UINT16_BE( group_id, group_ptr, 0 );
/* Write key_exchange_length */
MBEDTLS_PUT_UINT16_BE( key_exchange_len, group_ptr, 2 );
}
else
#endif /* MBEDTLS_ECDH_C */
if( 0 /* other KEMs? */ )
{
/* Do something */
}
else
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
/* Length of client_shares */
client_shares_len = p - client_shares_ptr;
if( client_shares_len == 0)
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "No key share defined." ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
/* Write extension_type */
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_KEY_SHARE, buf, 0 );
/* Write extension_data_length */
MBEDTLS_PUT_UINT16_BE( client_shares_len + 2, buf, 2 );
/* Write client_shares_length */
MBEDTLS_PUT_UINT16_BE( client_shares_len, buf, 4 );
/* Update offered_group_id field */
ssl->handshake->offered_group_id = group_id;
/* Output the total length of key_share extension. */
*olen = p - buf;
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, key_share extension", buf, *olen );
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_KEY_SHARE;
cleanup:
return( ret );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
/* Write cipher_suites
* CipherSuite cipher_suites<2..2^16-2>;
*/
static int ssl_tls13_write_client_hello_cipher_suites(
mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *olen )
{
unsigned char *p = buf;
const int *ciphersuite_list;
unsigned char *cipher_suites_ptr; /* Start of the cipher_suites list */
size_t cipher_suites_len;
*olen = 0 ;
/*
* Ciphersuite list
*
* This is a list of the symmetric cipher options supported by
* the client, specifically the record protection algorithm
* ( including secret key length ) and a hash to be used with
* HKDF, in descending order of client preference.
*/
ciphersuite_list = ssl->conf->ciphersuite_list;
/* Check there is space for the cipher suite list length (2 bytes). */
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
p += 2;
/* Write cipher_suites */
cipher_suites_ptr = p;
for ( size_t i = 0; ciphersuite_list[i] != 0; i++ )
{
int cipher_suite = ciphersuite_list[i];
const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
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 */
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