1506 lines
48 KiB
C
1506 lines
48 KiB
C
/*
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* TLS 1.3 server-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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#include "common.h"
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#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_PROTO_TLS1_3)
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#include "mbedtls/debug.h"
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#include "mbedtls/error.h"
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#include "mbedtls/platform.h"
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#include "ssl_misc.h"
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#include "ssl_tls13_keys.h"
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#include "ssl_debug_helpers.h"
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#if defined(MBEDTLS_ECP_C)
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#include "mbedtls/ecp.h"
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#endif /* MBEDTLS_ECP_C */
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#if defined(MBEDTLS_PLATFORM_C)
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#include "mbedtls/platform.h"
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#else
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#include <stdlib.h>
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#define mbedtls_calloc calloc
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#define mbedtls_free free
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#endif /* MBEDTLS_PLATFORM_C */
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#include "ssl_misc.h"
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#include "ssl_tls13_keys.h"
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#include "ssl_debug_helpers.h"
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/* From RFC 8446:
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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_parse_supported_versions_ext( mbedtls_ssl_context *ssl,
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const unsigned char *buf,
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const unsigned char *end )
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{
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const unsigned char *p = buf;
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size_t versions_len;
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const unsigned char *versions_end;
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uint16_t tls_version;
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int tls13_supported = 0;
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 1 );
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versions_len = p[0];
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p += 1;
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, versions_len );
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versions_end = p + versions_len;
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while( p < versions_end )
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{
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, versions_end, 2 );
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tls_version = mbedtls_ssl_read_version( p, ssl->conf->transport );
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p += 2;
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/* In this implementation we only support TLS 1.3 and DTLS 1.3. */
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if( tls_version == MBEDTLS_SSL_VERSION_TLS1_3 )
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{
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tls13_supported = 1;
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break;
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}
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}
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if( !tls13_supported )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLS 1.3 is not supported by the client" ) );
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MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION,
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MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION );
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return( MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION );
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}
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "Negotiated version. Supported is [%04x]",
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(unsigned int)tls_version ) );
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return( 0 );
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}
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#if defined(MBEDTLS_ECDH_C)
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/*
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*
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* From RFC 8446:
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* enum {
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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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static int ssl_tls13_parse_supported_groups_ext( mbedtls_ssl_context *ssl,
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const unsigned char *buf,
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const unsigned char *end )
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{
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const unsigned char *p = buf;
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size_t named_group_list_len;
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const unsigned char *named_group_list_end;
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MBEDTLS_SSL_DEBUG_BUF( 3, "supported_groups extension", p, end - buf );
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
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named_group_list_len = MBEDTLS_GET_UINT16_BE( p, 0 );
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p += 2;
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, named_group_list_len );
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named_group_list_end = p + named_group_list_len;
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ssl->handshake->hrr_selected_group = 0;
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while( p < named_group_list_end )
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{
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uint16_t named_group;
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, named_group_list_end, 2 );
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named_group = MBEDTLS_GET_UINT16_BE( p, 0 );
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p += 2;
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MBEDTLS_SSL_DEBUG_MSG( 2,
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( "got named group: %s(%04x)",
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mbedtls_ssl_named_group_to_str( named_group ),
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named_group ) );
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if( ! mbedtls_ssl_named_group_is_offered( ssl, named_group ) ||
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! mbedtls_ssl_named_group_is_supported( named_group ) ||
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ssl->handshake->hrr_selected_group != 0 )
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{
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continue;
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}
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MBEDTLS_SSL_DEBUG_MSG( 2,
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( "add named group %s(%04x) into received list.",
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mbedtls_ssl_named_group_to_str( named_group ),
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named_group ) );
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ssl->handshake->hrr_selected_group = named_group;
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}
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return( 0 );
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}
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#endif /* MBEDTLS_ECDH_C */
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#define SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH 1
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#if defined(MBEDTLS_ECDH_C)
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/*
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* ssl_tls13_parse_key_shares_ext() verifies whether the information in the
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* extension is correct and stores the first acceptable key share and its associated group.
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*
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* Possible return values are:
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* - 0: Successful processing of the client provided key share extension.
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* - SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH: The key shares provided by the client
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* does not match a group supported by the server. A HelloRetryRequest will
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* be needed.
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* - A negative value for fatal errors.
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*/
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static int ssl_tls13_parse_key_shares_ext( mbedtls_ssl_context *ssl,
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const unsigned char *buf,
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const unsigned char *end )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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unsigned char const *p = buf;
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unsigned char const *client_shares_end;
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size_t client_shares_len;
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/* From RFC 8446:
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*
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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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*/
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
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client_shares_len = MBEDTLS_GET_UINT16_BE( p, 0 );
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p += 2;
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, client_shares_len );
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ssl->handshake->offered_group_id = 0;
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client_shares_end = p + client_shares_len;
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/* We try to find a suitable key share entry and copy it to the
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* handshake context. Later, we have to find out whether we can do
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* something with the provided key share or whether we have to
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* dismiss it and send a HelloRetryRequest message.
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*/
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while( p < client_shares_end )
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{
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uint16_t group;
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size_t key_exchange_len;
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const unsigned char *key_exchange;
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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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*/
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, client_shares_end, 4 );
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group = MBEDTLS_GET_UINT16_BE( p, 0 );
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key_exchange_len = MBEDTLS_GET_UINT16_BE( p, 2 );
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p += 4;
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key_exchange = p;
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, client_shares_end, key_exchange_len );
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p += key_exchange_len;
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/* Continue parsing even if we have already found a match,
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* for input validation purposes.
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*/
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if( ! mbedtls_ssl_named_group_is_offered( ssl, group ) ||
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! mbedtls_ssl_named_group_is_supported( group ) ||
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ssl->handshake->offered_group_id != 0 )
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{
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continue;
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}
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/*
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* For now, we only support ECDHE groups.
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*/
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if( mbedtls_ssl_tls13_named_group_is_ecdhe( group ) )
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{
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MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDH group: %s (%04x)",
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mbedtls_ssl_named_group_to_str( group ),
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group ) );
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ret = mbedtls_ssl_tls13_read_public_ecdhe_share(
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ssl, key_exchange - 2, key_exchange_len + 2 );
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if( ret != 0 )
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return( ret );
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}
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else
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{
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MBEDTLS_SSL_DEBUG_MSG( 4, ( "Unrecognized NamedGroup %u",
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(unsigned) group ) );
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continue;
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}
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ssl->handshake->offered_group_id = group;
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}
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if( ssl->handshake->offered_group_id == 0 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching key share" ) );
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return( SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH );
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}
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return( 0 );
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}
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#endif /* MBEDTLS_ECDH_C */
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#if defined(MBEDTLS_DEBUG_C)
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static void ssl_tls13_debug_print_client_hello_exts( mbedtls_ssl_context *ssl )
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{
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((void) ssl);
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "Supported Extensions:" ) );
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "- KEY_SHARE_EXTENSION ( %s )",
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( ( ssl->handshake->extensions_present
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& MBEDTLS_SSL_EXT_KEY_SHARE ) > 0 ) ? "TRUE" : "FALSE" ) );
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "- PSK_KEY_EXCHANGE_MODES_EXTENSION ( %s )",
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( ( ssl->handshake->extensions_present
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& MBEDTLS_SSL_EXT_PSK_KEY_EXCHANGE_MODES ) > 0 ) ?
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"TRUE" : "FALSE" ) );
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "- PRE_SHARED_KEY_EXTENSION ( %s )",
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( ( ssl->handshake->extensions_present
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& MBEDTLS_SSL_EXT_PRE_SHARED_KEY ) > 0 ) ? "TRUE" : "FALSE" ) );
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "- SIGNATURE_ALGORITHM_EXTENSION ( %s )",
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( ( ssl->handshake->extensions_present
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& MBEDTLS_SSL_EXT_SIG_ALG ) > 0 ) ? "TRUE" : "FALSE" ) );
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "- SUPPORTED_GROUPS_EXTENSION ( %s )",
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( ( ssl->handshake->extensions_present
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& MBEDTLS_SSL_EXT_SUPPORTED_GROUPS ) >0 ) ?
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"TRUE" : "FALSE" ) );
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "- SUPPORTED_VERSION_EXTENSION ( %s )",
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( ( ssl->handshake->extensions_present
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& MBEDTLS_SSL_EXT_SUPPORTED_VERSIONS ) > 0 ) ?
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"TRUE" : "FALSE" ) );
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#if defined ( MBEDTLS_SSL_SERVER_NAME_INDICATION )
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "- SERVERNAME_EXTENSION ( %s )",
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( ( ssl->handshake->extensions_present
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& MBEDTLS_SSL_EXT_SERVERNAME ) > 0 ) ?
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"TRUE" : "FALSE" ) );
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#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
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}
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#endif /* MBEDTLS_DEBUG_C */
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static int ssl_tls13_client_hello_has_exts( mbedtls_ssl_context *ssl,
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int exts_mask )
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{
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int masked = ssl->handshake->extensions_present & exts_mask;
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return( masked == exts_mask );
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}
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static int ssl_tls13_client_hello_has_exts_for_ephemeral_key_exchange(
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mbedtls_ssl_context *ssl )
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{
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return( ssl_tls13_client_hello_has_exts( ssl,
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MBEDTLS_SSL_EXT_SUPPORTED_GROUPS |
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MBEDTLS_SSL_EXT_KEY_SHARE |
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MBEDTLS_SSL_EXT_SIG_ALG ) );
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}
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static int ssl_tls13_check_ephemeral_key_exchange( mbedtls_ssl_context *ssl )
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{
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if( !mbedtls_ssl_conf_tls13_ephemeral_enabled( ssl ) )
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return( 0 );
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if( !ssl_tls13_client_hello_has_exts_for_ephemeral_key_exchange( ssl ) )
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return( 0 );
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ssl->handshake->tls13_kex_modes =
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MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL;
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return( 1 );
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}
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/*
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*
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* STATE HANDLING: ClientHello
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*
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* There are three possible classes of outcomes when parsing the ClientHello:
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*
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* 1) The ClientHello was well-formed and matched the server's configuration.
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*
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* In this case, the server progresses to sending its ServerHello.
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*
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* 2) The ClientHello was well-formed but didn't match the server's
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* configuration.
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*
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* For example, the client might not have offered a key share which
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* the server supports, or the server might require a cookie.
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*
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* In this case, the server sends a HelloRetryRequest.
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*
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* 3) The ClientHello was ill-formed
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*
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* In this case, we abort the handshake.
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*
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*/
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/*
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* Structure of this message:
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*
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* uint16 ProtocolVersion;
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* opaque Random[32];
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* uint8 CipherSuite[2]; // Cryptographic suite selector
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*
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* struct {
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* ProtocolVersion legacy_version = 0x0303; // TLS v1.2
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* Random random;
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* opaque legacy_session_id<0..32>;
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* CipherSuite cipher_suites<2..2^16-2>;
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* opaque legacy_compression_methods<1..2^8-1>;
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* Extension extensions<8..2^16-1>;
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* } ClientHello;
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*/
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#define SSL_CLIENT_HELLO_OK 0
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#define SSL_CLIENT_HELLO_HRR_REQUIRED 1
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static int ssl_tls13_parse_client_hello( mbedtls_ssl_context *ssl,
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const unsigned char *buf,
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const unsigned char *end )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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const unsigned char *p = buf;
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size_t legacy_session_id_len;
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const unsigned char *cipher_suites;
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size_t cipher_suites_len;
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const unsigned char *cipher_suites_end;
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size_t extensions_len;
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const unsigned char *extensions_end;
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int hrr_required = 0;
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const mbedtls_ssl_ciphersuite_t* ciphersuite_info;
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ssl->handshake->extensions_present = MBEDTLS_SSL_EXT_NONE;
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/*
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* ClientHello layout:
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* 0 . 1 protocol version
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* 2 . 33 random bytes
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* 34 . 34 session id length ( 1 byte )
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* 35 . 34+x session id
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* .. . .. ciphersuite list length ( 2 bytes )
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* .. . .. ciphersuite list
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* .. . .. compression alg. list length ( 1 byte )
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* .. . .. compression alg. list
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* .. . .. extensions length ( 2 bytes, optional )
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* .. . .. extensions ( optional )
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*/
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/*
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* Minimal length ( with everything empty and extensions ommitted ) is
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* 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can
|
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* read at least up to session id length without worrying.
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*/
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 38 );
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|
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/* ...
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* ProtocolVersion legacy_version = 0x0303; // TLS 1.2
|
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* ...
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* with ProtocolVersion defined as:
|
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* uint16 ProtocolVersion;
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*/
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if( mbedtls_ssl_read_version( p, ssl->conf->transport ) !=
|
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MBEDTLS_SSL_VERSION_TLS1_2 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "Unsupported version of TLS." ) );
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MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION,
|
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MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION );
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return ( MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION );
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}
|
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p += 2;
|
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|
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/*
|
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* Only support TLS 1.3 currently, temporarily set the version.
|
|
*/
|
|
ssl->tls_version = MBEDTLS_SSL_VERSION_TLS1_3;
|
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|
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/* ...
|
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* Random random;
|
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* ...
|
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* with Random defined as:
|
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* opaque Random[32];
|
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*/
|
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MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes",
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p, MBEDTLS_CLIENT_HELLO_RANDOM_LEN );
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memcpy( &ssl->handshake->randbytes[0], p, MBEDTLS_CLIENT_HELLO_RANDOM_LEN );
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p += MBEDTLS_CLIENT_HELLO_RANDOM_LEN;
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|
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/* ...
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* opaque legacy_session_id<0..32>;
|
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* ...
|
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*/
|
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legacy_session_id_len = p[0];
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p++;
|
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|
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if( legacy_session_id_len > sizeof( ssl->session_negotiate->id ) )
|
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
|
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return( MBEDTLS_ERR_SSL_DECODE_ERROR );
|
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}
|
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|
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ssl->session_negotiate->id_len = legacy_session_id_len;
|
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MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id",
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p, legacy_session_id_len );
|
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/*
|
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* Check we have enough data for the legacy session identifier
|
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* and the ciphersuite list length.
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*/
|
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MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, legacy_session_id_len + 2 );
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memcpy( &ssl->session_negotiate->id[0], p, legacy_session_id_len );
|
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p += legacy_session_id_len;
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|
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cipher_suites_len = MBEDTLS_GET_UINT16_BE( p, 0 );
|
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p += 2;
|
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|
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/* Check we have enough data for the ciphersuite list, the legacy
|
|
* compression methods and the length of the extensions.
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, cipher_suites_len + 2 + 2 );
|
|
|
|
/* ...
|
|
* CipherSuite cipher_suites<2..2^16-2>;
|
|
* ...
|
|
* with CipherSuite defined as:
|
|
* uint8 CipherSuite[2];
|
|
*/
|
|
cipher_suites = p;
|
|
cipher_suites_end = p + cipher_suites_len;
|
|
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
|
|
p, cipher_suites_len );
|
|
/*
|
|
* Search for a matching ciphersuite
|
|
*/
|
|
int ciphersuite_match = 0;
|
|
for ( ; p < cipher_suites_end; p += 2 )
|
|
{
|
|
uint16_t cipher_suite;
|
|
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, cipher_suites_end, 2 );
|
|
cipher_suite = MBEDTLS_GET_UINT16_BE( p, 0 );
|
|
ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( cipher_suite );
|
|
/*
|
|
* Check whether this ciphersuite is valid and offered.
|
|
*/
|
|
if( ( mbedtls_ssl_validate_ciphersuite(
|
|
ssl, ciphersuite_info, ssl->tls_version,
|
|
ssl->tls_version ) != 0 ) ||
|
|
! mbedtls_ssl_tls13_cipher_suite_is_offered( ssl, cipher_suite ) )
|
|
{
|
|
continue;
|
|
}
|
|
|
|
ssl->session_negotiate->ciphersuite = cipher_suite;
|
|
ssl->handshake->ciphersuite_info = ciphersuite_info;
|
|
ciphersuite_match = 1;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if( ! ciphersuite_match )
|
|
{
|
|
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE,
|
|
MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
|
|
return ( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
|
|
}
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s",
|
|
ciphersuite_info->name ) );
|
|
|
|
p = cipher_suites + cipher_suites_len;
|
|
|
|
/* ...
|
|
* opaque legacy_compression_methods<1..2^8-1>;
|
|
* ...
|
|
*/
|
|
if( p[0] != 1 || p[1] != MBEDTLS_SSL_COMPRESS_NULL )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad legacy compression method" ) );
|
|
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER,
|
|
MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
|
|
return ( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
|
|
}
|
|
p += 2;
|
|
|
|
/* ...
|
|
* Extension extensions<8..2^16-1>;
|
|
* ...
|
|
* with Extension defined as:
|
|
* struct {
|
|
* ExtensionType extension_type;
|
|
* opaque extension_data<0..2^16-1>;
|
|
* } Extension;
|
|
*/
|
|
extensions_len = MBEDTLS_GET_UINT16_BE( p, 0 );
|
|
p += 2;
|
|
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, extensions_len );
|
|
extensions_end = p + extensions_len;
|
|
|
|
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", p, extensions_len );
|
|
|
|
while( p < extensions_end )
|
|
{
|
|
unsigned int extension_type;
|
|
size_t extension_data_len;
|
|
const unsigned char *extension_data_end;
|
|
|
|
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, extensions_end, 4 );
|
|
extension_type = MBEDTLS_GET_UINT16_BE( p, 0 );
|
|
extension_data_len = MBEDTLS_GET_UINT16_BE( p, 2 );
|
|
p += 4;
|
|
|
|
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, extensions_end, extension_data_len );
|
|
extension_data_end = p + extension_data_len;
|
|
|
|
switch( extension_type )
|
|
{
|
|
#if defined(MBEDTLS_ECDH_C)
|
|
case MBEDTLS_TLS_EXT_SUPPORTED_GROUPS:
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported group extension" ) );
|
|
|
|
/* Supported Groups Extension
|
|
*
|
|
* When sent by the client, the "supported_groups" extension
|
|
* indicates the named groups which the client supports,
|
|
* ordered from most preferred to least preferred.
|
|
*/
|
|
ret = ssl_tls13_parse_supported_groups_ext(
|
|
ssl, p, extension_data_end );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1,
|
|
"mbedtls_ssl_parse_supported_groups_ext", ret );
|
|
return( ret );
|
|
}
|
|
|
|
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_GROUPS;
|
|
break;
|
|
#endif /* MBEDTLS_ECDH_C */
|
|
|
|
#if defined(MBEDTLS_ECDH_C)
|
|
case MBEDTLS_TLS_EXT_KEY_SHARE:
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found key share extension" ) );
|
|
|
|
/*
|
|
* Key Share Extension
|
|
*
|
|
* When sent by the client, the "key_share" extension
|
|
* contains the endpoint's cryptographic parameters for
|
|
* ECDHE/DHE key establishment methods.
|
|
*/
|
|
ret = ssl_tls13_parse_key_shares_ext(
|
|
ssl, p, extension_data_end );
|
|
if( ret == SSL_TLS1_3_PARSE_KEY_SHARES_EXT_NO_MATCH )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "HRR needed " ) );
|
|
hrr_required = 1;
|
|
}
|
|
|
|
if( ret < 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET(
|
|
1, "ssl_tls13_parse_key_shares_ext", ret );
|
|
return( ret );
|
|
}
|
|
|
|
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_KEY_SHARE;
|
|
break;
|
|
#endif /* MBEDTLS_ECDH_C */
|
|
|
|
case MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS:
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported versions extension" ) );
|
|
|
|
ret = ssl_tls13_parse_supported_versions_ext(
|
|
ssl, p, extension_data_end );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1,
|
|
( "ssl_tls13_parse_supported_versions_ext" ), ret );
|
|
return( ret );
|
|
}
|
|
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SUPPORTED_VERSIONS;
|
|
break;
|
|
|
|
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
|
|
case MBEDTLS_TLS_EXT_SIG_ALG:
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
|
|
|
|
ret = mbedtls_ssl_tls13_parse_sig_alg_ext(
|
|
ssl, p, extension_data_end );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 1,
|
|
( "ssl_parse_supported_signature_algorithms_server_ext ( %d )",
|
|
ret ) );
|
|
return( ret );
|
|
}
|
|
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SIG_ALG;
|
|
break;
|
|
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
|
|
|
|
default:
|
|
MBEDTLS_SSL_DEBUG_MSG( 3,
|
|
( "unknown extension found: %ud ( ignoring )",
|
|
extension_type ) );
|
|
}
|
|
|
|
p += extension_data_len;
|
|
}
|
|
|
|
/* Update checksum with either
|
|
* - The entire content of the CH message, if no PSK extension is present
|
|
* - The content up to but excluding the PSK extension, if present.
|
|
*/
|
|
mbedtls_ssl_add_hs_msg_to_checksum( ssl, MBEDTLS_SSL_HS_CLIENT_HELLO,
|
|
buf, p - buf );
|
|
|
|
/* List all the extensions we have received */
|
|
#if defined(MBEDTLS_DEBUG_C)
|
|
ssl_tls13_debug_print_client_hello_exts( ssl );
|
|
#endif /* MBEDTLS_DEBUG_C */
|
|
|
|
/*
|
|
* Here we only support the ephemeral or (EC)DHE key echange mode
|
|
*/
|
|
|
|
if( !ssl_tls13_check_ephemeral_key_exchange( ssl ) )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG(
|
|
1,
|
|
( "ClientHello message misses mandatory extensions." ) );
|
|
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_MISSING_EXTENSION ,
|
|
MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
|
|
return( MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER );
|
|
}
|
|
|
|
return( hrr_required ? SSL_CLIENT_HELLO_HRR_REQUIRED : SSL_CLIENT_HELLO_OK );
|
|
}
|
|
|
|
/* Update the handshake state machine */
|
|
|
|
static int ssl_tls13_postprocess_client_hello( mbedtls_ssl_context* ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
|
|
ret = mbedtls_ssl_tls13_key_schedule_stage_early( ssl );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1,
|
|
"mbedtls_ssl_tls1_3_key_schedule_stage_early", ret );
|
|
return( ret );
|
|
}
|
|
|
|
return( 0 );
|
|
|
|
}
|
|
|
|
/*
|
|
* Main entry point from the state machine; orchestrates the otherfunctions.
|
|
*/
|
|
|
|
static int ssl_tls13_process_client_hello( mbedtls_ssl_context *ssl )
|
|
{
|
|
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char* buf = NULL;
|
|
size_t buflen = 0;
|
|
int parse_client_hello_ret ;
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_fetch_handshake_msg(
|
|
ssl, MBEDTLS_SSL_HS_CLIENT_HELLO,
|
|
&buf, &buflen ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK_NEG( ssl_tls13_parse_client_hello( ssl, buf,
|
|
buf + buflen ) );
|
|
|
|
parse_client_hello_ret = ret;
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_postprocess_client_hello( ssl ) );
|
|
|
|
if( parse_client_hello_ret == SSL_CLIENT_HELLO_OK )
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_HELLO );
|
|
else
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_HELLO_RETRY_REQUEST );
|
|
|
|
cleanup:
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
|
|
return( ret );
|
|
}
|
|
|
|
/*
|
|
* Handler for MBEDTLS_SSL_SERVER_HELLO
|
|
*/
|
|
static int ssl_tls13_prepare_server_hello( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char *server_randbytes =
|
|
ssl->handshake->randbytes + MBEDTLS_CLIENT_HELLO_RANDOM_LEN;
|
|
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, server_randbytes,
|
|
MBEDTLS_SERVER_HELLO_RANDOM_LEN ) ) != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1, "f_rng", ret );
|
|
return( ret );
|
|
}
|
|
|
|
MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", server_randbytes,
|
|
MBEDTLS_SERVER_HELLO_RANDOM_LEN );
|
|
|
|
#if defined(MBEDTLS_HAVE_TIME)
|
|
ssl->session_negotiate->start = time( NULL );
|
|
#endif /* MBEDTLS_HAVE_TIME */
|
|
|
|
return( ret );
|
|
}
|
|
|
|
/*
|
|
* ssl_tls13_write_server_hello_supported_versions_ext ():
|
|
*
|
|
* struct {
|
|
* ProtocolVersion selected_version;
|
|
* } SupportedVersions;
|
|
*/
|
|
static int ssl_tls13_write_server_hello_supported_versions_ext(
|
|
mbedtls_ssl_context *ssl,
|
|
unsigned char *buf,
|
|
unsigned char *end,
|
|
size_t *out_len )
|
|
{
|
|
*out_len = 0;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, write selected version" ) );
|
|
|
|
/* Check if we have space to write the extension:
|
|
* - extension_type (2 bytes)
|
|
* - extension_data_length (2 bytes)
|
|
* - selected_version (2 bytes)
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 6 );
|
|
|
|
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS, buf, 0 );
|
|
|
|
MBEDTLS_PUT_UINT16_BE( 2, buf, 2 );
|
|
|
|
mbedtls_ssl_write_version( buf + 4,
|
|
ssl->conf->transport,
|
|
ssl->tls_version );
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "supported version: [%04x]",
|
|
ssl->tls_version ) );
|
|
|
|
*out_len = 6;
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
|
|
|
|
/* Generate and export a single key share. For hybrid KEMs, this can
|
|
* be called multiple times with the different components of the hybrid. */
|
|
static int ssl_tls13_generate_and_write_key_share( mbedtls_ssl_context *ssl,
|
|
uint16_t named_group,
|
|
unsigned char *buf,
|
|
unsigned char *end,
|
|
size_t *out_len )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
|
|
*out_len = 0;
|
|
|
|
#if defined(MBEDTLS_ECDH_C)
|
|
if( mbedtls_ssl_tls13_named_group_is_ecdhe( named_group ) )
|
|
{
|
|
ret = mbedtls_ssl_tls13_generate_and_write_ecdh_key_exchange(
|
|
ssl, named_group, buf, end, out_len );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET(
|
|
1, "mbedtls_ssl_tls13_generate_and_write_ecdh_key_exchange",
|
|
ret );
|
|
return( ret );
|
|
}
|
|
}
|
|
else
|
|
#endif /* MBEDTLS_ECDH_C */
|
|
if( 0 /* Other kinds of KEMs */ )
|
|
{
|
|
}
|
|
else
|
|
{
|
|
((void) ssl);
|
|
((void) named_group);
|
|
((void) buf);
|
|
((void) end);
|
|
ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
|
|
}
|
|
|
|
return( ret );
|
|
}
|
|
|
|
/*
|
|
* ssl_tls13_write_key_share_ext
|
|
*
|
|
* Structure of key_share extension in ServerHello:
|
|
*
|
|
* struct {
|
|
* NamedGroup group;
|
|
* opaque key_exchange<1..2^16-1>;
|
|
* } KeyShareEntry;
|
|
* struct {
|
|
* KeyShareEntry server_share;
|
|
* } KeyShareServerHello;
|
|
*/
|
|
static int ssl_tls13_write_key_share_ext( mbedtls_ssl_context *ssl,
|
|
unsigned char *buf,
|
|
unsigned char *end,
|
|
size_t *out_len )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char *p = buf;
|
|
uint16_t group = ssl->handshake->offered_group_id;
|
|
unsigned char *server_share = buf + 4;
|
|
size_t key_exchange_length;
|
|
|
|
*out_len = 0;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding key share extension" ) );
|
|
|
|
/* Check if we have space for header and length fields:
|
|
* - extension_type (2 bytes)
|
|
* - extension_data_length (2 bytes)
|
|
* - group (2 bytes)
|
|
* - key_exchange_length (2 bytes)
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 8 );
|
|
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_KEY_SHARE, p, 0 );
|
|
MBEDTLS_PUT_UINT16_BE( group, server_share, 0 );
|
|
p += 8;
|
|
|
|
/* When we introduce PQC-ECDHE hybrids, we'll want to call this
|
|
* function multiple times. */
|
|
ret = ssl_tls13_generate_and_write_key_share(
|
|
ssl, group, server_share + 4, end, &key_exchange_length );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
p += key_exchange_length;
|
|
|
|
MBEDTLS_PUT_UINT16_BE( key_exchange_length, server_share + 2, 0 );
|
|
|
|
MBEDTLS_PUT_UINT16_BE( p - server_share, buf, 2 );
|
|
|
|
*out_len = p - buf;
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
static int ssl_tls13_write_hrr_key_share_ext( mbedtls_ssl_context *ssl,
|
|
unsigned char *buf,
|
|
unsigned char *end,
|
|
size_t *out_len )
|
|
{
|
|
uint16_t selected_group = ssl->handshake->hrr_selected_group;
|
|
/* key_share Extension
|
|
*
|
|
* struct {
|
|
* select (Handshake.msg_type) {
|
|
* ...
|
|
* case hello_retry_request:
|
|
* NamedGroup selected_group;
|
|
* ...
|
|
* };
|
|
* } KeyShare;
|
|
*/
|
|
|
|
*out_len = 0;
|
|
|
|
/*
|
|
* For a pure PSK key exchange, there is no group to agree upon. The purpose
|
|
* of the HRR is then to transmit a cookie to force the client to demonstrate
|
|
* reachability at their apparent network address (primarily useful for DTLS).
|
|
*/
|
|
if( ! mbedtls_ssl_tls13_some_ephemeral_enabled( ssl ) )
|
|
return( 0 );
|
|
|
|
/* We should only send the key_share extension if the client's initial
|
|
* key share was not acceptable. */
|
|
if( ssl->handshake->offered_group_id != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 4, ( "Skip key_share extension in HRR" ) );
|
|
return( 0 );
|
|
}
|
|
|
|
if( selected_group == 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching named group found" ) );
|
|
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
|
|
}
|
|
|
|
/* Check if we have enough space:
|
|
* - extension_type (2 bytes)
|
|
* - extension_data_length (2 bytes)
|
|
* - selected_group (2 bytes)
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_READ_PTR( buf, end, 6 );
|
|
|
|
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_KEY_SHARE, buf, 0 );
|
|
MBEDTLS_PUT_UINT16_BE( 2, buf, 2 );
|
|
MBEDTLS_PUT_UINT16_BE( selected_group, buf, 4 );
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 3,
|
|
( "HRR selected_group: %s (%x)",
|
|
mbedtls_ssl_named_group_to_str( selected_group ),
|
|
selected_group ) );
|
|
|
|
*out_len = 6;
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Structure of ServerHello message:
|
|
*
|
|
* struct {
|
|
* ProtocolVersion legacy_version = 0x0303; // TLS v1.2
|
|
* Random random;
|
|
* opaque legacy_session_id_echo<0..32>;
|
|
* CipherSuite cipher_suite;
|
|
* uint8 legacy_compression_method = 0;
|
|
* Extension extensions<6..2^16-1>;
|
|
* } ServerHello;
|
|
*/
|
|
static int ssl_tls13_write_server_hello_body( mbedtls_ssl_context *ssl,
|
|
unsigned char *buf,
|
|
unsigned char *end,
|
|
size_t *out_len,
|
|
int is_hrr )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char *p = buf;
|
|
unsigned char *p_extensions_len;
|
|
size_t output_len;
|
|
|
|
*out_len = 0;
|
|
|
|
/* ...
|
|
* ProtocolVersion legacy_version = 0x0303; // TLS 1.2
|
|
* ...
|
|
* with ProtocolVersion defined as:
|
|
* uint16 ProtocolVersion;
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
|
|
MBEDTLS_PUT_UINT16_BE( 0x0303, p, 0 );
|
|
p += 2;
|
|
|
|
/* ...
|
|
* Random random;
|
|
* ...
|
|
* with Random defined as:
|
|
* opaque Random[MBEDTLS_SERVER_HELLO_RANDOM_LEN];
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, MBEDTLS_SERVER_HELLO_RANDOM_LEN );
|
|
if( is_hrr )
|
|
{
|
|
memcpy( p, mbedtls_ssl_tls13_hello_retry_request_magic,
|
|
MBEDTLS_SERVER_HELLO_RANDOM_LEN );
|
|
}
|
|
else
|
|
{
|
|
memcpy( p, &ssl->handshake->randbytes[MBEDTLS_CLIENT_HELLO_RANDOM_LEN],
|
|
MBEDTLS_SERVER_HELLO_RANDOM_LEN );
|
|
}
|
|
MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes",
|
|
p, MBEDTLS_SERVER_HELLO_RANDOM_LEN );
|
|
p += MBEDTLS_SERVER_HELLO_RANDOM_LEN;
|
|
|
|
/* ...
|
|
* opaque legacy_session_id_echo<0..32>;
|
|
* ...
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 + ssl->session_negotiate->id_len );
|
|
*p++ = (unsigned char)ssl->session_negotiate->id_len;
|
|
if( ssl->session_negotiate->id_len > 0 )
|
|
{
|
|
memcpy( p, &ssl->session_negotiate->id[0],
|
|
ssl->session_negotiate->id_len );
|
|
p += ssl->session_negotiate->id_len;
|
|
|
|
MBEDTLS_SSL_DEBUG_BUF( 3, "session id", ssl->session_negotiate->id,
|
|
ssl->session_negotiate->id_len );
|
|
}
|
|
|
|
/* ...
|
|
* CipherSuite cipher_suite;
|
|
* ...
|
|
* with CipherSuite defined as:
|
|
* uint8 CipherSuite[2];
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
|
|
MBEDTLS_PUT_UINT16_BE( ssl->session_negotiate->ciphersuite, p, 0 );
|
|
p += 2;
|
|
MBEDTLS_SSL_DEBUG_MSG( 3,
|
|
( "server hello, chosen ciphersuite: %s ( id=%d )",
|
|
mbedtls_ssl_get_ciphersuite_name(
|
|
ssl->session_negotiate->ciphersuite ),
|
|
ssl->session_negotiate->ciphersuite ) );
|
|
|
|
/* ...
|
|
* uint8 legacy_compression_method = 0;
|
|
* ...
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 );
|
|
*p++ = 0x0;
|
|
|
|
/* ...
|
|
* Extension extensions<6..2^16-1>;
|
|
* ...
|
|
* struct {
|
|
* ExtensionType extension_type; (2 bytes)
|
|
* opaque extension_data<0..2^16-1>;
|
|
* } Extension;
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
|
|
p_extensions_len = p;
|
|
p += 2;
|
|
|
|
if( ( ret = ssl_tls13_write_server_hello_supported_versions_ext(
|
|
ssl, p, end, &output_len ) ) != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET(
|
|
1, "ssl_tls13_write_server_hello_supported_versions_ext", ret );
|
|
return( ret );
|
|
}
|
|
p += output_len;
|
|
|
|
if( mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
|
|
{
|
|
if( is_hrr )
|
|
ret = ssl_tls13_write_hrr_key_share_ext( ssl, p, end, &output_len );
|
|
else
|
|
ret = ssl_tls13_write_key_share_ext( ssl, p, end, &output_len );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
p += output_len;
|
|
}
|
|
|
|
MBEDTLS_PUT_UINT16_BE( p - p_extensions_len - 2, p_extensions_len, 0 );
|
|
|
|
MBEDTLS_SSL_DEBUG_BUF( 4, "server hello extensions",
|
|
p_extensions_len, p - p_extensions_len );
|
|
|
|
*out_len = p - buf;
|
|
|
|
MBEDTLS_SSL_DEBUG_BUF( 3, "server hello", buf, *out_len );
|
|
|
|
return( ret );
|
|
}
|
|
|
|
static int ssl_tls13_finalize_write_server_hello( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
ret = mbedtls_ssl_tls13_compute_handshake_transform( ssl );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1,
|
|
"mbedtls_ssl_tls13_compute_handshake_transform",
|
|
ret );
|
|
return( ret );
|
|
}
|
|
|
|
mbedtls_ssl_set_outbound_transform( ssl,
|
|
ssl->handshake->transform_handshake );
|
|
MBEDTLS_SSL_DEBUG_MSG(
|
|
3, ( "switching to handshake transform for outbound data" ) );
|
|
|
|
return( ret );
|
|
}
|
|
|
|
static int ssl_tls13_write_server_hello( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char *buf;
|
|
size_t buf_len, msg_len;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_prepare_server_hello( ssl ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( ssl,
|
|
MBEDTLS_SSL_HS_SERVER_HELLO, &buf, &buf_len ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_server_hello_body( ssl, buf,
|
|
buf + buf_len,
|
|
&msg_len,
|
|
0 ) );
|
|
|
|
mbedtls_ssl_add_hs_msg_to_checksum(
|
|
ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg(
|
|
ssl, buf_len, msg_len ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_finalize_write_server_hello( ssl ) );
|
|
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS );
|
|
|
|
cleanup:
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
|
|
return( ret );
|
|
}
|
|
|
|
/*
|
|
* Handler for MBEDTLS_SSL_ENCRYPTED_EXTENSIONS
|
|
*/
|
|
|
|
/*
|
|
* struct {
|
|
* Extension extensions<0..2 ^ 16 - 1>;
|
|
* } EncryptedExtensions;
|
|
*
|
|
*/
|
|
static int ssl_tls13_write_encrypted_extensions_body( mbedtls_ssl_context *ssl,
|
|
unsigned char *buf,
|
|
unsigned char *end,
|
|
size_t *out_len )
|
|
{
|
|
unsigned char *p = buf;
|
|
size_t extensions_len = 0;
|
|
unsigned char *p_extensions_len;
|
|
|
|
*out_len = 0;
|
|
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
|
|
p_extensions_len = p;
|
|
p += 2;
|
|
|
|
((void) ssl);
|
|
|
|
extensions_len = ( p - p_extensions_len ) - 2;
|
|
MBEDTLS_PUT_UINT16_BE( extensions_len, p_extensions_len, 0 );
|
|
|
|
*out_len = p - buf;
|
|
|
|
MBEDTLS_SSL_DEBUG_BUF( 4, "encrypted extensions", buf, *out_len );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
static int ssl_tls13_write_encrypted_extensions( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char *buf;
|
|
size_t buf_len, msg_len;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write encrypted extensions" ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( ssl,
|
|
MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, &buf, &buf_len ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_encrypted_extensions_body(
|
|
ssl, buf, buf + buf_len, &msg_len ) );
|
|
|
|
mbedtls_ssl_add_hs_msg_to_checksum(
|
|
ssl, MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS, buf, msg_len );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg(
|
|
ssl, buf_len, msg_len ) );
|
|
|
|
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
|
|
if( mbedtls_ssl_tls13_some_psk_enabled( ssl ) )
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED );
|
|
else
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CERTIFICATE_REQUEST );
|
|
#else
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED );
|
|
#endif
|
|
|
|
cleanup:
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write encrypted extensions" ) );
|
|
return( ret );
|
|
}
|
|
|
|
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
|
|
#define SSL_CERTIFICATE_REQUEST_SEND_REQUEST 0
|
|
#define SSL_CERTIFICATE_REQUEST_SKIP 1
|
|
/* Coordination:
|
|
* Check whether a CertificateRequest message should be written.
|
|
* Returns a negative code on failure, or
|
|
* - SSL_CERTIFICATE_REQUEST_SEND_REQUEST
|
|
* - SSL_CERTIFICATE_REQUEST_SKIP
|
|
* indicating if the writing of the CertificateRequest
|
|
* should be skipped or not.
|
|
*/
|
|
static int ssl_tls13_certificate_request_coordinate( mbedtls_ssl_context *ssl )
|
|
{
|
|
int authmode;
|
|
|
|
authmode = ssl->conf->authmode;
|
|
|
|
if( authmode == MBEDTLS_SSL_VERIFY_NONE )
|
|
return( SSL_CERTIFICATE_REQUEST_SKIP );
|
|
|
|
return( SSL_CERTIFICATE_REQUEST_SEND_REQUEST );
|
|
}
|
|
|
|
/*
|
|
* struct {
|
|
* opaque certificate_request_context<0..2^8-1>;
|
|
* Extension extensions<2..2^16-1>;
|
|
* } CertificateRequest;
|
|
*
|
|
*/
|
|
static int ssl_tls13_write_certificate_request_body( mbedtls_ssl_context *ssl,
|
|
unsigned char *buf,
|
|
const unsigned char *end,
|
|
size_t *out_len )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char *p = buf;
|
|
size_t output_len = 0;
|
|
unsigned char *p_extensions_len;
|
|
|
|
*out_len = 0;
|
|
|
|
/* Check if we have enough space:
|
|
* - certificate_request_context (1 byte)
|
|
* - extensions length (2 bytes)
|
|
*/
|
|
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 3 );
|
|
|
|
/*
|
|
* Write certificate_request_context
|
|
*/
|
|
/*
|
|
* We use a zero length context for the normal handshake
|
|
* messages. For post-authentication handshake messages
|
|
* this request context would be set to a non-zero value.
|
|
*/
|
|
*p++ = 0x0;
|
|
|
|
/*
|
|
* Write extensions
|
|
*/
|
|
/* The extensions must contain the signature_algorithms. */
|
|
p_extensions_len = p;
|
|
p += 2;
|
|
ret = mbedtls_ssl_write_sig_alg_ext( ssl, p, end, &output_len );
|
|
if( ret != 0 )
|
|
return( ret );
|
|
|
|
p += output_len;
|
|
MBEDTLS_PUT_UINT16_BE( p - p_extensions_len - 2, p_extensions_len, 0 );
|
|
|
|
*out_len = p - buf;
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
static int ssl_tls13_write_certificate_request( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK_NEG( ssl_tls13_certificate_request_coordinate( ssl ) );
|
|
|
|
if( ret == SSL_CERTIFICATE_REQUEST_SEND_REQUEST )
|
|
{
|
|
unsigned char *buf;
|
|
size_t buf_len, msg_len;
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg( ssl,
|
|
MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, &buf, &buf_len ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_certificate_request_body(
|
|
ssl, buf, buf + buf_len, &msg_len ) );
|
|
|
|
mbedtls_ssl_add_hs_msg_to_checksum(
|
|
ssl, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, buf, msg_len );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg(
|
|
ssl, buf_len, msg_len ) );
|
|
}
|
|
else if( ret == SSL_CERTIFICATE_REQUEST_SKIP )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
|
|
ret = 0;
|
|
}
|
|
else
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
|
|
ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
|
|
goto cleanup;
|
|
}
|
|
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_CERTIFICATE );
|
|
cleanup:
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
|
|
return( ret );
|
|
}
|
|
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
|
|
|
|
/*
|
|
* Handler for MBEDTLS_SSL_HELLO_RETRY_REQUEST
|
|
*/
|
|
|
|
static int ssl_tls13_write_hello_retry_request_coordinate(
|
|
mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
if( ssl->handshake->hello_retry_request_count > 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Too many HRRs" ) );
|
|
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE,
|
|
MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
|
|
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
|
|
}
|
|
|
|
/*
|
|
* Create stateless transcript hash for HRR
|
|
*/
|
|
MBEDTLS_SSL_DEBUG_MSG( 4, ( "Reset transcript for HRR" ) );
|
|
ret = mbedtls_ssl_reset_transcript_for_hrr( ssl );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_reset_transcript_for_hrr", ret );
|
|
return( ret );
|
|
}
|
|
mbedtls_ssl_session_reset_msg_layer( ssl, 0 );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
static int ssl_tls13_write_hello_retry_request( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char *buf;
|
|
size_t buf_len, msg_len;
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello retry request" ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_hello_retry_request_coordinate( ssl ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_start_handshake_msg(
|
|
ssl, MBEDTLS_SSL_HS_SERVER_HELLO,
|
|
&buf, &buf_len ) );
|
|
|
|
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_server_hello_body( ssl, buf,
|
|
buf + buf_len,
|
|
&msg_len,
|
|
1 ) );
|
|
mbedtls_ssl_add_hs_msg_to_checksum(
|
|
ssl, MBEDTLS_SSL_HS_SERVER_HELLO, buf, msg_len );
|
|
|
|
|
|
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg( ssl, buf_len,
|
|
msg_len ) );
|
|
|
|
ssl->handshake->hello_retry_request_count++;
|
|
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_HELLO );
|
|
|
|
cleanup:
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello retry request" ) );
|
|
return( ret );
|
|
}
|
|
|
|
/*
|
|
* TLS 1.3 State Machine -- server side
|
|
*/
|
|
int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
|
|
if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL )
|
|
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
|
|
|
|
MBEDTLS_SSL_DEBUG_MSG( 2, ( "tls13 server state: %s(%d)",
|
|
mbedtls_ssl_states_str( ssl->state ),
|
|
ssl->state ) );
|
|
|
|
switch( ssl->state )
|
|
{
|
|
/* start state */
|
|
case MBEDTLS_SSL_HELLO_REQUEST:
|
|
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_HELLO );
|
|
ret = 0;
|
|
break;
|
|
|
|
case MBEDTLS_SSL_CLIENT_HELLO:
|
|
|
|
ret = ssl_tls13_process_client_hello( ssl );
|
|
if( ret != 0 )
|
|
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_process_client_hello", ret );
|
|
|
|
break;
|
|
|
|
case MBEDTLS_SSL_SERVER_HELLO:
|
|
ret = ssl_tls13_write_server_hello( ssl );
|
|
break;
|
|
|
|
case MBEDTLS_SSL_ENCRYPTED_EXTENSIONS:
|
|
ret = ssl_tls13_write_encrypted_extensions( ssl );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_encrypted_extensions", ret );
|
|
return( ret );
|
|
}
|
|
|
|
case MBEDTLS_SSL_HELLO_RETRY_REQUEST:
|
|
ret = ssl_tls13_write_hello_retry_request( ssl );
|
|
if( ret != 0 )
|
|
{
|
|
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_tls13_write_hello_retry_request", ret );
|
|
return( ret );
|
|
}
|
|
break;
|
|
|
|
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
|
|
case MBEDTLS_SSL_CERTIFICATE_REQUEST:
|
|
ret = ssl_tls13_write_certificate_request( ssl );
|
|
break;
|
|
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
|
|
|
|
default:
|
|
MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
|
|
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
|
|
}
|
|
|
|
return( ret );
|
|
}
|
|
|
|
#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_PROTO_TLS1_3 */
|