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ssl_cli.c
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/*
* SSLv3/TLSv1 client-side functions
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* 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)
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_SSL_CLI_C)
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdlib.h>
#define mbedtls_calloc calloc
#define mbedtls_free free
#endif
#include "mbedtls/debug.h"
#include "mbedtls/ssl.h"
#include "mbedtls/ssl_internal.h"
#include <string.h>
#include <stdint.h>
#if defined(MBEDTLS_HAVE_TIME)
#include "mbedtls/platform_time.h"
#endif
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize( void *v, size_t n ) {
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
}
#endif
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
static void ssl_write_hostname_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
size_t hostname_len;
*olen = 0;
if( ssl->hostname == NULL )
return;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding server name extension: %s",
ssl->hostname ) );
hostname_len = strlen( ssl->hostname );
if( end < p || (size_t)( end - p ) < hostname_len + 9 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
/*
* struct {
* NameType name_type;
* select (name_type) {
* case host_name: HostName;
* } name;
* } ServerName;
*
* enum {
* host_name(0), (255)
* } NameType;
*
* opaque HostName<1..2^16-1>;
*
* struct {
* ServerName server_name_list<1..2^16-1>
* } ServerNameList;
*/
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME ) & 0xFF );
*p++ = (unsigned char)( ( (hostname_len + 5) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( (hostname_len + 5) ) & 0xFF );
*p++ = (unsigned char)( ( (hostname_len + 3) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( (hostname_len + 3) ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME ) & 0xFF );
*p++ = (unsigned char)( ( hostname_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( hostname_len ) & 0xFF );
memcpy( p, ssl->hostname, hostname_len );
*olen = hostname_len + 9;
}
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
#if defined(MBEDTLS_SSL_RENEGOTIATION)
static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
*olen = 0;
if( ssl->renego_status != MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
return;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding renegotiation extension" ) );
if( end < p || (size_t)( end - p ) < 5 + ssl->verify_data_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
/*
* Secure renegotiation
*/
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO ) & 0xFF );
*p++ = 0x00;
*p++ = ( ssl->verify_data_len + 1 ) & 0xFF;
*p++ = ssl->verify_data_len & 0xFF;
memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
*olen = 5 + ssl->verify_data_len;
}
#endif /* MBEDTLS_SSL_RENEGOTIATION */
/*
* Only if we handle at least one key exchange that needs signatures.
*/
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
static void ssl_write_signature_algorithms_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
size_t sig_alg_len = 0;
const int *md;
#if defined(MBEDTLS_RSA_C) || defined(MBEDTLS_ECDSA_C)
unsigned char *sig_alg_list = buf + 6;
#endif
*olen = 0;
if( ssl->conf->max_minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 )
return;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding signature_algorithms extension" ) );
for( md = ssl->conf->sig_hashes; *md != MBEDTLS_MD_NONE; md++ )
{
#if defined(MBEDTLS_ECDSA_C)
sig_alg_len += 2;
#endif
#if defined(MBEDTLS_RSA_C)
sig_alg_len += 2;
#endif
}
if( end < p || (size_t)( end - p ) < sig_alg_len + 6 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
/*
* Prepare signature_algorithms extension (TLS 1.2)
*/
sig_alg_len = 0;
for( md = ssl->conf->sig_hashes; *md != MBEDTLS_MD_NONE; md++ )
{
#if defined(MBEDTLS_ECDSA_C)
sig_alg_list[sig_alg_len++] = mbedtls_ssl_hash_from_md_alg( *md );
sig_alg_list[sig_alg_len++] = MBEDTLS_SSL_SIG_ECDSA;
#endif
#if defined(MBEDTLS_RSA_C)
sig_alg_list[sig_alg_len++] = mbedtls_ssl_hash_from_md_alg( *md );
sig_alg_list[sig_alg_len++] = MBEDTLS_SSL_SIG_RSA;
#endif
}
/*
* enum {
* none(0), md5(1), sha1(2), sha224(3), sha256(4), sha384(5),
* sha512(6), (255)
* } HashAlgorithm;
*
* enum { anonymous(0), rsa(1), dsa(2), ecdsa(3), (255) }
* SignatureAlgorithm;
*
* struct {
* HashAlgorithm hash;
* SignatureAlgorithm signature;
* } SignatureAndHashAlgorithm;
*
* SignatureAndHashAlgorithm
* supported_signature_algorithms<2..2^16-2>;
*/
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SIG_ALG >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SIG_ALG ) & 0xFF );
*p++ = (unsigned char)( ( ( sig_alg_len + 2 ) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ( sig_alg_len + 2 ) ) & 0xFF );
*p++ = (unsigned char)( ( sig_alg_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( sig_alg_len ) & 0xFF );
*olen = 6 + sig_alg_len;
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
static void ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
unsigned char *elliptic_curve_list = p + 6;
size_t elliptic_curve_len = 0;
const mbedtls_ecp_curve_info *info;
#if defined(MBEDTLS_ECP_C)
const mbedtls_ecp_group_id *grp_id;
#else
((void) ssl);
#endif
*olen = 0;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_elliptic_curves extension" ) );
#if defined(MBEDTLS_ECP_C)
for( grp_id = ssl->conf->curve_list; *grp_id != MBEDTLS_ECP_DP_NONE; grp_id++ )
#else
for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ )
#endif
{
#if defined(MBEDTLS_ECP_C)
info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
#endif
if( info == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid curve in ssl configuration" ) );
return;
}
elliptic_curve_len += 2;
}
if( end < p || (size_t)( end - p ) < 6 + elliptic_curve_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
elliptic_curve_len = 0;
#if defined(MBEDTLS_ECP_C)
for( grp_id = ssl->conf->curve_list; *grp_id != MBEDTLS_ECP_DP_NONE; grp_id++ )
#else
for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ )
#endif
{
#if defined(MBEDTLS_ECP_C)
info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
#endif
elliptic_curve_list[elliptic_curve_len++] = info->tls_id >> 8;
elliptic_curve_list[elliptic_curve_len++] = info->tls_id & 0xFF;
}
if( elliptic_curve_len == 0 )
return;
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES ) & 0xFF );
*p++ = (unsigned char)( ( ( elliptic_curve_len + 2 ) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ( elliptic_curve_len + 2 ) ) & 0xFF );
*p++ = (unsigned char)( ( ( elliptic_curve_len ) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ( elliptic_curve_len ) ) & 0xFF );
*olen = 6 + elliptic_curve_len;
}
static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
*olen = 0;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported_point_formats extension" ) );
if( end < p || (size_t)( end - p ) < 6 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS ) & 0xFF );
*p++ = 0x00;
*p++ = 2;
*p++ = 1;
*p++ = MBEDTLS_ECP_PF_UNCOMPRESSED;
*olen = 6;
}
#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
int ret;
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
size_t kkpp_len;
*olen = 0;
/* Skip costly extension if we can't use EC J-PAKE anyway */
if( mbedtls_ecjpake_check( &ssl->handshake->ecjpake_ctx ) != 0 )
return;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding ecjpake_kkpp extension" ) );
if( end - p < 4 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP ) & 0xFF );
/*
* We may need to send ClientHello multiple times for Hello verification.
* We don't want to compute fresh values every time (both for performance
* and consistency reasons), so cache the extension content.
*/
if( ssl->handshake->ecjpake_cache == NULL ||
ssl->handshake->ecjpake_cache_len == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "generating new ecjpake parameters" ) );
ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx,
p + 2, end - p - 2, &kkpp_len,
ssl->conf->f_rng, ssl->conf->p_rng );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret );
return;
}
ssl->handshake->ecjpake_cache = mbedtls_calloc( 1, kkpp_len );
if( ssl->handshake->ecjpake_cache == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "allocation failed" ) );
return;
}
memcpy( ssl->handshake->ecjpake_cache, p + 2, kkpp_len );
ssl->handshake->ecjpake_cache_len = kkpp_len;
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "re-using cached ecjpake parameters" ) );
kkpp_len = ssl->handshake->ecjpake_cache_len;
if( (size_t)( end - p - 2 ) < kkpp_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
memcpy( p + 2, ssl->handshake->ecjpake_cache, kkpp_len );
}
*p++ = (unsigned char)( ( kkpp_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( kkpp_len ) & 0xFF );
*olen = kkpp_len + 4;
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
*olen = 0;
if( ssl->conf->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE ) {
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding max_fragment_length extension" ) );
if( end < p || (size_t)( end - p ) < 5 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH ) & 0xFF );
*p++ = 0x00;
*p++ = 1;
*p++ = ssl->conf->mfl_code;
*olen = 5;
}
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
static void ssl_write_truncated_hmac_ext( mbedtls_ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
*olen = 0;
if( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED )
{
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding truncated_hmac extension" ) );
if( end < p || (size_t)( end - p ) < 4 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_TRUNCATED_HMAC ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
static void ssl_write_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
*olen = 0;
if( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED ||
ssl->conf->max_minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
{
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding encrypt_then_mac "
"extension" ) );
if( end < p || (size_t)( end - p ) < 4 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
static void ssl_write_extended_ms_ext( mbedtls_ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
*olen = 0;
if( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED ||
ssl->conf->max_minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
{
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding extended_master_secret "
"extension" ) );
if( end < p || (size_t)( end - p ) < 4 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
static void ssl_write_session_ticket_ext( mbedtls_ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
size_t tlen = ssl->session_negotiate->ticket_len;
*olen = 0;
if( ssl->conf->session_tickets == MBEDTLS_SSL_SESSION_TICKETS_DISABLED )
{
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding session ticket extension" ) );
if( end < p || (size_t)( end - p ) < 4 + tlen )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET ) & 0xFF );
*p++ = (unsigned char)( ( tlen >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( tlen ) & 0xFF );
*olen = 4;
if( ssl->session_negotiate->ticket == NULL || tlen == 0 )
{
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "sending session ticket of length %d", tlen ) );
memcpy( p, ssl->session_negotiate->ticket, tlen );
*olen += tlen;
}
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
#if defined(MBEDTLS_SSL_ALPN)
static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
unsigned char *p = buf;
const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
size_t alpnlen = 0;
const char **cur;
*olen = 0;
if( ssl->conf->alpn_list == NULL )
{
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding alpn extension" ) );
for( cur = ssl->conf->alpn_list; *cur != NULL; cur++ )
alpnlen += (unsigned char)( strlen( *cur ) & 0xFF ) + 1;
if( end < p || (size_t)( end - p ) < 6 + alpnlen )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN ) & 0xFF );
/*
* opaque ProtocolName<1..2^8-1>;
*
* struct {
* ProtocolName protocol_name_list<2..2^16-1>
* } ProtocolNameList;
*/
/* Skip writing extension and list length for now */
p += 4;
for( cur = ssl->conf->alpn_list; *cur != NULL; cur++ )
{
*p = (unsigned char)( strlen( *cur ) & 0xFF );
memcpy( p + 1, *cur, *p );
p += 1 + *p;
}
*olen = p - buf;
/* List length = olen - 2 (ext_type) - 2 (ext_len) - 2 (list_len) */
buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF );
buf[5] = (unsigned char)( ( ( *olen - 6 ) ) & 0xFF );
/* Extension length = olen - 2 (ext_type) - 2 (ext_len) */
buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF );
buf[3] = (unsigned char)( ( ( *olen - 4 ) ) & 0xFF );
}
#endif /* MBEDTLS_SSL_ALPN */
/*
* Generate random bytes for ClientHello
*/
static int ssl_generate_random( mbedtls_ssl_context *ssl )
{
int ret;
unsigned char *p = ssl->handshake->randbytes;
#if defined(MBEDTLS_HAVE_TIME)
mbedtls_time_t t;
#endif
/*
* When responding to a verify request, MUST reuse random (RFC 6347 4.2.1)
*/
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
ssl->handshake->verify_cookie != NULL )
{
return( 0 );
}
#endif
#if defined(MBEDTLS_HAVE_TIME)
t = mbedtls_time( NULL );
*p++ = (unsigned char)( t >> 24 );
*p++ = (unsigned char)( t >> 16 );
*p++ = (unsigned char)( t >> 8 );
*p++ = (unsigned char)( t );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, current time: %lu", t ) );
#else
if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 4 ) ) != 0 )
return( ret );
p += 4;
#endif /* MBEDTLS_HAVE_TIME */
if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, p, 28 ) ) != 0 )
return( ret );
return( 0 );
}
static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
{
int ret;
size_t i, n, olen, ext_len = 0;
unsigned char *buf;
unsigned char *p, *q;
unsigned char offer_compress;
const int *ciphersuites;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write client hello" ) );
if( ssl->conf->f_rng == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") );
return( MBEDTLS_ERR_SSL_NO_RNG );
}
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
#endif
{
ssl->major_ver = ssl->conf->min_major_ver;
ssl->minor_ver = ssl->conf->min_minor_ver;
}
if( ssl->conf->max_major_ver == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "configured max major version is invalid, "
"consider using mbedtls_ssl_config_defaults()" ) );
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
}
/*
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 highest version supported
* 6 . 9 current UNIX time
* 10 . 37 random bytes
*/
buf = ssl->out_msg;
p = buf + 4;
mbedtls_ssl_write_version( ssl->conf->max_major_ver, ssl->conf->max_minor_ver,
ssl->conf->transport, p );
p += 2;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, max version: [%d:%d]",
buf[4], buf[5] ) );
if( ( ret = ssl_generate_random( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_generate_random", ret );
return( ret );
}
memcpy( p, ssl->handshake->randbytes, 32 );
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", p, 32 );
p += 32;
/*
* 38 . 38 session id length
* 39 . 39+n session id
* 39+n . 39+n DTLS only: cookie length (1 byte)
* 40+n . .. DTSL only: cookie
* .. . .. ciphersuitelist length (2 bytes)
* .. . .. ciphersuitelist
* .. . .. compression methods length (1 byte)
* .. . .. compression methods
* .. . .. extensions length (2 bytes)
* .. . .. extensions
*/
n = ssl->session_negotiate->id_len;
if( n < 16 || n > 32 ||
#if defined(MBEDTLS_SSL_RENEGOTIATION)
ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE ||
#endif
ssl->handshake->resume == 0 )
{
n = 0;
}
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
/*
* RFC 5077 section 3.4: "When presenting a ticket, the client MAY
* generate and include a Session ID in the TLS ClientHello."
*/
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
#endif
{
if( ssl->session_negotiate->ticket != NULL &&
ssl->session_negotiate->ticket_len != 0 )
{
ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id, 32 );
if( ret != 0 )
return( ret );
ssl->session_negotiate->id_len = n = 32;
}
}
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
*p++ = (unsigned char) n;
for( i = 0; i < n; i++ )
*p++ = ssl->session_negotiate->id[i];
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, session id len.: %d", n ) );
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", buf + 39, n );
/*
* DTLS cookie
*/
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
{
if( ssl->handshake->verify_cookie == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "no verify cookie to send" ) );
*p++ = 0;
}
else
{
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, cookie",
ssl->handshake->verify_cookie,
ssl->handshake->verify_cookie_len );
*p++ = ssl->handshake->verify_cookie_len;
memcpy( p, ssl->handshake->verify_cookie,
ssl->handshake->verify_cookie_len );
p += ssl->handshake->verify_cookie_len;
}
}
#endif
/*
* Ciphersuite list
*/
ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
/* Skip writing ciphersuite length for now */
n = 0;
q = p;
p += 2;
for( i = 0; ciphersuites[i] != 0; i++ )
{
ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( ciphersuites[i] );
if( ciphersuite_info == NULL )
continue;
if( ciphersuite_info->min_minor_ver > ssl->conf->max_minor_ver ||
ciphersuite_info->max_minor_ver < ssl->conf->min_minor_ver )
continue;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
( ciphersuite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) )
continue;
#endif
#if defined(MBEDTLS_ARC4_C)
if( ssl->conf->arc4_disabled == MBEDTLS_SSL_ARC4_DISABLED &&
ciphersuite_info->cipher == MBEDTLS_CIPHER_ARC4_128 )
continue;
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE &&
mbedtls_ecjpake_check( &ssl->handshake->ecjpake_ctx ) != 0 )
continue;
#endif
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %04x",
ciphersuites[i] ) );
n++;
*p++ = (unsigned char)( ciphersuites[i] >> 8 );
*p++ = (unsigned char)( ciphersuites[i] );
}
/*
* Add TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
#endif
{
*p++ = (unsigned char)( MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO >> 8 );
*p++ = (unsigned char)( MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO );
n++;
}
/* Some versions of OpenSSL don't handle it correctly if not at end */
#if defined(MBEDTLS_SSL_FALLBACK_SCSV)
if( ssl->conf->fallback == MBEDTLS_SSL_IS_FALLBACK )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding FALLBACK_SCSV" ) );
*p++ = (unsigned char)( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 );
*p++ = (unsigned char)( MBEDTLS_SSL_FALLBACK_SCSV_VALUE );
n++;
}
#endif
*q++ = (unsigned char)( n >> 7 );
*q++ = (unsigned char)( n << 1 );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, got %d ciphersuites", n ) );
#if defined(MBEDTLS_ZLIB_SUPPORT)
offer_compress = 1;
#else
offer_compress = 0;
#endif
/*
* We don't support compression with DTLS right now: is many records come
* in the same datagram, uncompressing one could overwrite the next one.
* We don't want to add complexity for handling that case unless there is
* an actual need for it.
*/
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
offer_compress = 0;
#endif
if( offer_compress )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, compress len.: %d", 2 ) );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, compress alg.: %d %d",
MBEDTLS_SSL_COMPRESS_DEFLATE, MBEDTLS_SSL_COMPRESS_NULL ) );
*p++ = 2;
*p++ = MBEDTLS_SSL_COMPRESS_DEFLATE;
*p++ = MBEDTLS_SSL_COMPRESS_NULL;
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, compress len.: %d", 1 ) );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, compress alg.: %d",
MBEDTLS_SSL_COMPRESS_NULL ) );
*p++ = 1;
*p++ = MBEDTLS_SSL_COMPRESS_NULL;
}
// First write extensions, then the total length
//
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
ssl_write_hostname_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_RENEGOTIATION)
ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
ssl_write_signature_algorithms_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_supported_elliptic_curves_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl_write_ecjpake_kkpp_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif