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mbedtls/library/ssl_srv.c
Janos Follath 3fbdadad7b SSL: Make use of the new ECDH interface 
The SSL module accesses ECDH context members directly. This can't work
with the new context, where we can't make any assumption about the
implementation of the context.

This commit makes use of the new functions to avoid accessing ECDH
members directly. The only members that are still accessed directly are
the group ID and the point format and they are independent from the
implementation.
2018-12-06 12:22:46 +00:00

4380 lines
149 KiB
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/*
* SSLv3/TLSv1 server-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_SRV_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 "mbedtls/platform_util.h"
#include <string.h>
#if defined(MBEDTLS_ECP_C)
#include "mbedtls/ecp.h"
#endif
#if defined(MBEDTLS_HAVE_TIME)
#include "mbedtls/platform_time.h"
#endif
#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
int mbedtls_ssl_set_client_transport_id( mbedtls_ssl_context *ssl,
const unsigned char *info,
size_t ilen )
{
if( ssl->conf->endpoint != MBEDTLS_SSL_IS_SERVER )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
mbedtls_free( ssl->cli_id );
if( ( ssl->cli_id = mbedtls_calloc( 1, ilen ) ) == NULL )
return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
memcpy( ssl->cli_id, info, ilen );
ssl->cli_id_len = ilen;
return( 0 );
}
void mbedtls_ssl_conf_dtls_cookies( mbedtls_ssl_config *conf,
mbedtls_ssl_cookie_write_t *f_cookie_write,
mbedtls_ssl_cookie_check_t *f_cookie_check,
void *p_cookie )
{
conf->f_cookie_write = f_cookie_write;
conf->f_cookie_check = f_cookie_check;
conf->p_cookie = p_cookie;
}
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
static int ssl_parse_servername_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
int ret;
size_t servername_list_size, hostname_len;
const unsigned char *p;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "parse ServerName extension" ) );
if( len < 2 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
servername_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
if( servername_list_size + 2 != len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
p = buf + 2;
while( servername_list_size > 2 )
{
hostname_len = ( ( p[1] << 8 ) | p[2] );
if( hostname_len + 3 > servername_list_size )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( p[0] == MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME )
{
ret = ssl->conf->f_sni( ssl->conf->p_sni,
ssl, p + 3, hostname_len );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "ssl_sni_wrapper", ret );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
return( 0 );
}
servername_list_size -= hostname_len + 3;
p += hostname_len + 3;
}
if( servername_list_size != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
return( 0 );
}
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
{
/* Check verify-data in constant-time. The length OTOH is no secret */
if( len != 1 + ssl->verify_data_len ||
buf[0] != ssl->verify_data_len ||
mbedtls_ssl_safer_memcmp( buf + 1, ssl->peer_verify_data,
ssl->verify_data_len ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
else
#endif /* MBEDTLS_SSL_RENEGOTIATION */
{
if( len != 1 || buf[0] != 0x0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-zero length renegotiation info" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
}
return( 0 );
}
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
/*
* Status of the implementation of signature-algorithms extension:
*
* Currently, we are only considering the signature-algorithm extension
* to pick a ciphersuite which allows us to send the ServerKeyExchange
* message with a signature-hash combination that the user allows.
*
* We do *not* check whether all certificates in our certificate
* chain are signed with an allowed signature-hash pair.
* This needs to be done at a later stage.
*
*/
static int ssl_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
size_t sig_alg_list_size;
const unsigned char *p;
const unsigned char *end = buf + len;
mbedtls_md_type_t md_cur;
mbedtls_pk_type_t sig_cur;
if ( len < 2 ) {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
sig_alg_list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
if( sig_alg_list_size + 2 != len ||
sig_alg_list_size % 2 != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/* Currently we only guarantee signing the ServerKeyExchange message according
* to the constraints specified in this extension (see above), so it suffices
* to remember only one suitable hash for each possible signature algorithm.
*
* This will change when we also consider certificate signatures,
* in which case we will need to remember the whole signature-hash
* pair list from the extension.
*/
for( p = buf + 2; p < end; p += 2 )
{
/* Silently ignore unknown signature or hash algorithms. */
if( ( sig_cur = mbedtls_ssl_pk_alg_from_sig( p[1] ) ) == MBEDTLS_PK_NONE )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext"
" unknown sig alg encoding %d", p[1] ) );
continue;
}
/* Check if we support the hash the user proposes */
md_cur = mbedtls_ssl_md_alg_from_hash( p[0] );
if( md_cur == MBEDTLS_MD_NONE )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:"
" unknown hash alg encoding %d", p[0] ) );
continue;
}
if( mbedtls_ssl_check_sig_hash( ssl, md_cur ) == 0 )
{
mbedtls_ssl_sig_hash_set_add( &ssl->handshake->hash_algs, sig_cur, md_cur );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext:"
" match sig %d and hash %d",
sig_cur, md_cur ) );
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: "
"hash alg %d not supported", md_cur ) );
}
}
return( 0 );
}
#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 int ssl_parse_supported_elliptic_curves( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
size_t list_size, our_size;
const unsigned char *p;
const mbedtls_ecp_curve_info *curve_info, **curves;
if ( len < 2 ) {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
list_size = ( ( buf[0] << 8 ) | ( buf[1] ) );
if( list_size + 2 != len ||
list_size % 2 != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/* Should never happen unless client duplicates the extension */
if( ssl->handshake->curves != NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/* Don't allow our peer to make us allocate too much memory,
* and leave room for a final 0 */
our_size = list_size / 2 + 1;
if( our_size > MBEDTLS_ECP_DP_MAX )
our_size = MBEDTLS_ECP_DP_MAX;
if( ( curves = mbedtls_calloc( our_size, sizeof( *curves ) ) ) == NULL )
{
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
}
ssl->handshake->curves = curves;
p = buf + 2;
while( list_size > 0 && our_size > 1 )
{
curve_info = mbedtls_ecp_curve_info_from_tls_id( ( p[0] << 8 ) | p[1] );
if( curve_info != NULL )
{
*curves++ = curve_info;
our_size--;
}
list_size -= 2;
p += 2;
}
return( 0 );
}
static int ssl_parse_supported_point_formats( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
size_t list_size;
const unsigned char *p;
if( len == 0 || (size_t)( buf[0] + 1 ) != len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
list_size = buf[0];
p = buf + 1;
while( list_size > 0 )
{
if( p[0] == MBEDTLS_ECP_PF_UNCOMPRESSED ||
p[0] == MBEDTLS_ECP_PF_COMPRESSED )
{
#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
ssl->handshake->ecdh_ctx.point_format = p[0];
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
ssl->handshake->ecjpake_ctx.point_format = p[0];
#endif
MBEDTLS_SSL_DEBUG_MSG( 4, ( "point format selected: %d", p[0] ) );
return( 0 );
}
list_size--;
p++;
}
return( 0 );
}
#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
int ret;
if( mbedtls_ecjpake_check( &ssl->handshake->ecjpake_ctx ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip ecjpake kkpp extension" ) );
return( 0 );
}
if( ( ret = mbedtls_ecjpake_read_round_one( &ssl->handshake->ecjpake_ctx,
buf, len ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_one", ret );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
return( ret );
}
/* Only mark the extension as OK when we're sure it is */
ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK;
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
static int ssl_parse_max_fragment_length_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( len != 1 || buf[0] >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->session_negotiate->mfl_code = buf[0];
return( 0 );
}
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
static int ssl_parse_truncated_hmac_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( len != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
((void) buf);
if( ssl->conf->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_ENABLED )
ssl->session_negotiate->trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED;
return( 0 );
}
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( len != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
((void) buf);
if( ssl->conf->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED &&
ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
{
ssl->session_negotiate->encrypt_then_mac = MBEDTLS_SSL_ETM_ENABLED;
}
return( 0 );
}
#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
static int ssl_parse_extended_ms_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( len != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
((void) buf);
if( ssl->conf->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED &&
ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
{
ssl->handshake->extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED;
}
return( 0 );
}
#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
static int ssl_parse_session_ticket_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t len )
{
int ret;
mbedtls_ssl_session session;
mbedtls_ssl_session_init( &session );
if( ssl->conf->f_ticket_parse == NULL ||
ssl->conf->f_ticket_write == NULL )
{
return( 0 );
}
/* Remember the client asked us to send a new ticket */
ssl->handshake->new_session_ticket = 1;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket length: %d", len ) );
if( len == 0 )
return( 0 );
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket rejected: renegotiating" ) );
return( 0 );
}
#endif /* MBEDTLS_SSL_RENEGOTIATION */
/*
* Failures are ok: just ignore the ticket and proceed.
*/
if( ( ret = ssl->conf->f_ticket_parse( ssl->conf->p_ticket, &session,
buf, len ) ) != 0 )
{
mbedtls_ssl_session_free( &session );
if( ret == MBEDTLS_ERR_SSL_INVALID_MAC )
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is not authentic" ) );
else if( ret == MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED )
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ticket is expired" ) );
else
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_parse", ret );
return( 0 );
}
/*
* Keep the session ID sent by the client, since we MUST send it back to
* inform them we're accepting the ticket (RFC 5077 section 3.4)
*/
session.id_len = ssl->session_negotiate->id_len;
memcpy( &session.id, ssl->session_negotiate->id, session.id_len );
mbedtls_ssl_session_free( ssl->session_negotiate );
memcpy( ssl->session_negotiate, &session, sizeof( mbedtls_ssl_session ) );
/* Zeroize instead of free as we copied the content */
mbedtls_platform_zeroize( &session, sizeof( mbedtls_ssl_session ) );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from ticket" ) );
ssl->handshake->resume = 1;
/* Don't send a new ticket after all, this one is OK */
ssl->handshake->new_session_ticket = 0;
return( 0 );
}
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
#if defined(MBEDTLS_SSL_ALPN)
static int ssl_parse_alpn_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf, size_t len )
{
size_t list_len, cur_len, ours_len;
const unsigned char *theirs, *start, *end;
const char **ours;
/* If ALPN not configured, just ignore the extension */
if( ssl->conf->alpn_list == NULL )
return( 0 );
/*
* opaque ProtocolName<1..2^8-1>;
*
* struct {
* ProtocolName protocol_name_list<2..2^16-1>
* } ProtocolNameList;
*/
/* Min length is 2 (list_len) + 1 (name_len) + 1 (name) */
if( len < 4 )
{
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
list_len = ( buf[0] << 8 ) | buf[1];
if( list_len != len - 2 )
{
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/*
* Validate peer's list (lengths)
*/
start = buf + 2;
end = buf + len;
for( theirs = start; theirs != end; theirs += cur_len )
{
cur_len = *theirs++;
/* Current identifier must fit in list */
if( cur_len > (size_t)( end - theirs ) )
{
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/* Empty strings MUST NOT be included */
if( cur_len == 0 )
{
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
/*
* Use our order of preference
*/
for( ours = ssl->conf->alpn_list; *ours != NULL; ours++ )
{
ours_len = strlen( *ours );
for( theirs = start; theirs != end; theirs += cur_len )
{
cur_len = *theirs++;
if( cur_len == ours_len &&
memcmp( theirs, *ours, cur_len ) == 0 )
{
ssl->alpn_chosen = *ours;
return( 0 );
}
}
}
/* If we get there, no match was found */
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
#endif /* MBEDTLS_SSL_ALPN */
/*
* Auxiliary functions for ServerHello parsing and related actions
*/
#if defined(MBEDTLS_X509_CRT_PARSE_C)
/*
* Return 0 if the given key uses one of the acceptable curves, -1 otherwise
*/
#if defined(MBEDTLS_ECDSA_C)
static int ssl_check_key_curve( mbedtls_pk_context *pk,
const mbedtls_ecp_curve_info **curves )
{
const mbedtls_ecp_curve_info **crv = curves;
mbedtls_ecp_group_id grp_id = mbedtls_pk_ec( *pk )->grp.id;
while( *crv != NULL )
{
if( (*crv)->grp_id == grp_id )
return( 0 );
crv++;
}
return( -1 );
}
#endif /* MBEDTLS_ECDSA_C */
/*
* Try picking a certificate for this ciphersuite,
* return 0 on success and -1 on failure.
*/
static int ssl_pick_cert( mbedtls_ssl_context *ssl,
const mbedtls_ssl_ciphersuite_t * ciphersuite_info )
{
mbedtls_ssl_key_cert *cur, *list, *fallback = NULL;
mbedtls_pk_type_t pk_alg =
mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
uint32_t flags;
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if( ssl->handshake->sni_key_cert != NULL )
list = ssl->handshake->sni_key_cert;
else
#endif
list = ssl->conf->key_cert;
if( pk_alg == MBEDTLS_PK_NONE )
return( 0 );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite requires certificate" ) );
if( list == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server has no certificate" ) );
return( -1 );
}
for( cur = list; cur != NULL; cur = cur->next )
{
MBEDTLS_SSL_DEBUG_CRT( 3, "candidate certificate chain, certificate",
cur->cert );
if( ! mbedtls_pk_can_do( &cur->cert->pk, pk_alg ) )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: key type" ) );
continue;
}
/*
* This avoids sending the client a cert it'll reject based on
* keyUsage or other extensions.
*
* It also allows the user to provision different certificates for
* different uses based on keyUsage, eg if they want to avoid signing
* and decrypting with the same RSA key.
*/
if( mbedtls_ssl_check_cert_usage( cur->cert, ciphersuite_info,
MBEDTLS_SSL_IS_SERVER, &flags ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: "
"(extended) key usage extension" ) );
continue;
}
#if defined(MBEDTLS_ECDSA_C)
if( pk_alg == MBEDTLS_PK_ECDSA &&
ssl_check_key_curve( &cur->cert->pk, ssl->handshake->curves ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate mismatch: elliptic curve" ) );
continue;
}
#endif
/*
* Try to select a SHA-1 certificate for pre-1.2 clients, but still
* present them a SHA-higher cert rather than failing if it's the only
* one we got that satisfies the other conditions.
*/
if( ssl->minor_ver < MBEDTLS_SSL_MINOR_VERSION_3 &&
cur->cert->sig_md != MBEDTLS_MD_SHA1 )
{
if( fallback == NULL )
fallback = cur;
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "certificate not preferred: "
"sha-2 with pre-TLS 1.2 client" ) );
continue;
}
}
/* If we get there, we got a winner */
break;
}
if( cur == NULL )
cur = fallback;
/* Do not update ssl->handshake->key_cert unless there is a match */
if( cur != NULL )
{
ssl->handshake->key_cert = cur;
MBEDTLS_SSL_DEBUG_CRT( 3, "selected certificate chain, certificate",
ssl->handshake->key_cert->cert );
return( 0 );
}
return( -1 );
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */
/*
* Check if a given ciphersuite is suitable for use with our config/keys/etc
* Sets ciphersuite_info only if the suite matches.
*/
static int ssl_ciphersuite_match( mbedtls_ssl_context *ssl, int suite_id,
const mbedtls_ssl_ciphersuite_t **ciphersuite_info )
{
const mbedtls_ssl_ciphersuite_t *suite_info;
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
mbedtls_pk_type_t sig_type;
#endif
suite_info = mbedtls_ssl_ciphersuite_from_id( suite_id );
if( suite_info == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "trying ciphersuite: %s", suite_info->name ) );
if( suite_info->min_minor_ver > ssl->minor_ver ||
suite_info->max_minor_ver < ssl->minor_ver )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: version" ) );
return( 0 );
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
( suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) )
return( 0 );
#endif
#if defined(MBEDTLS_ARC4_C)
if( ssl->conf->arc4_disabled == MBEDTLS_SSL_ARC4_DISABLED &&
suite_info->cipher == MBEDTLS_CIPHER_ARC4_128 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: rc4" ) );
return( 0 );
}
#endif
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
if( suite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE &&
( ssl->handshake->cli_exts & MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK ) == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: ecjpake "
"not configured or ext missing" ) );
return( 0 );
}
#endif
#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
if( mbedtls_ssl_ciphersuite_uses_ec( suite_info ) &&
( ssl->handshake->curves == NULL ||
ssl->handshake->curves[0] == NULL ) )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
"no common elliptic curve" ) );
return( 0 );
}
#endif
#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
/* If the ciphersuite requires a pre-shared key and we don't
* have one, skip it now rather than failing later */
if( mbedtls_ssl_ciphersuite_uses_psk( suite_info ) &&
ssl->conf->f_psk == NULL &&
( ssl->conf->psk == NULL || ssl->conf->psk_identity == NULL ||
ssl->conf->psk_identity_len == 0 || ssl->conf->psk_len == 0 ) )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no pre-shared key" ) );
return( 0 );
}
#endif
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
/* If the ciphersuite requires signing, check whether
* a suitable hash algorithm is present. */
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
{
sig_type = mbedtls_ssl_get_ciphersuite_sig_alg( suite_info );
if( sig_type != MBEDTLS_PK_NONE &&
mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs, sig_type ) == MBEDTLS_MD_NONE )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: no suitable hash algorithm "
"for signature algorithm %d", sig_type ) );
return( 0 );
}
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
#if defined(MBEDTLS_X509_CRT_PARSE_C)
/*
* Final check: if ciphersuite requires us to have a
* certificate/key of a particular type:
* - select the appropriate certificate if we have one, or
* - try the next ciphersuite if we don't
* This must be done last since we modify the key_cert list.
*/
if( ssl_pick_cert( ssl, suite_info ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciphersuite mismatch: "
"no suitable certificate" ) );
return( 0 );
}
#endif
*ciphersuite_info = suite_info;
return( 0 );
}
#if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
{
int ret, got_common_suite;
unsigned int i, j;
size_t n;
unsigned int ciph_len, sess_len, chal_len;
unsigned char *buf, *p;
const int *ciphersuites;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) );
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
#endif /* MBEDTLS_SSL_RENEGOTIATION */
buf = ssl->in_hdr;
MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, 5 );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d",
buf[2] ) );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d",
( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]",
buf[3], buf[4] ) );
/*
* SSLv2 Client Hello
*
* Record layer:
* 0 . 1 message length
*
* SSL layer:
* 2 . 2 message type
* 3 . 4 protocol version
*/
if( buf[2] != MBEDTLS_SSL_HS_CLIENT_HELLO ||
buf[3] != MBEDTLS_SSL_MAJOR_VERSION_3 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF;
if( n < 17 || n > 512 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->major_ver = MBEDTLS_SSL_MAJOR_VERSION_3;
ssl->minor_ver = ( buf[4] <= ssl->conf->max_minor_ver )
? buf[4] : ssl->conf->max_minor_ver;
if( ssl->minor_ver < ssl->conf->min_minor_ver )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
" [%d:%d] < [%d:%d]",
ssl->major_ver, ssl->minor_ver,
ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
}
ssl->handshake->max_major_ver = buf[3];
ssl->handshake->max_minor_ver = buf[4];
if( ( ret = mbedtls_ssl_fetch_input( ssl, 2 + n ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
return( ret );
}
ssl->handshake->update_checksum( ssl, buf + 2, n );
buf = ssl->in_msg;
n = ssl->in_left - 5;
/*
* 0 . 1 ciphersuitelist length
* 2 . 3 session id length
* 4 . 5 challenge length
* 6 . .. ciphersuitelist
* .. . .. session id
* .. . .. challenge
*/
MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, n );
ciph_len = ( buf[0] << 8 ) | buf[1];
sess_len = ( buf[2] << 8 ) | buf[3];
chal_len = ( buf[4] << 8 ) | buf[5];
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciph_len: %d, sess_len: %d, chal_len: %d",
ciph_len, sess_len, chal_len ) );
/*
* Make sure each parameter length is valid
*/
if( ciph_len < 3 || ( ciph_len % 3 ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( sess_len > 32 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( chal_len < 8 || chal_len > 32 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( n != 6 + ciph_len + sess_len + chal_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
buf + 6, ciph_len );
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id",
buf + 6 + ciph_len, sess_len );
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, challenge",
buf + 6 + ciph_len + sess_len, chal_len );
p = buf + 6 + ciph_len;
ssl->session_negotiate->id_len = sess_len;
memset( ssl->session_negotiate->id, 0,
sizeof( ssl->session_negotiate->id ) );
memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->id_len );
p += sess_len;
memset( ssl->handshake->randbytes, 0, 64 );
memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len );
/*
* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
{
if( p[0] == 0 && p[1] == 0 && p[2] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
"during renegotiation" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
#endif /* MBEDTLS_SSL_RENEGOTIATION */
ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
break;
}
}
#if defined(MBEDTLS_SSL_FALLBACK_SCSV)
for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
{
if( p[0] == 0 &&
p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) &&
p[2] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) );
if( ssl->minor_ver < ssl->conf->max_minor_ver )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
break;
}
}
#endif /* MBEDTLS_SSL_FALLBACK_SCSV */
got_common_suite = 0;
ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
ciphersuite_info = NULL;
#if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
for( i = 0; ciphersuites[i] != 0; i++ )
#else
for( i = 0; ciphersuites[i] != 0; i++ )
for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
#endif
{
if( p[0] != 0 ||
p[1] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
p[2] != ( ( ciphersuites[i] ) & 0xFF ) )
continue;
got_common_suite = 1;
if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
&ciphersuite_info ) ) != 0 )
return( ret );
if( ciphersuite_info != NULL )
goto have_ciphersuite_v2;
}
if( got_common_suite )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
"but none of them usable" ) );
return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
}
have_ciphersuite_v2:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
ssl->session_negotiate->ciphersuite = ciphersuites[i];
ssl->transform_negotiate->ciphersuite_info = ciphersuite_info;
/*
* SSLv2 Client Hello relevant renegotiation security checks
*/
if( ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->in_left = 0;
ssl->state++;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello v2" ) );
return( 0 );
}
#endif /* MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */
/* This function doesn't alert on errors that happen early during
ClientHello parsing because they might indicate that the client is
not talking SSL/TLS at all and would not understand our alert. */
static int ssl_parse_client_hello( mbedtls_ssl_context *ssl )
{
int ret, got_common_suite;
size_t i, j;
size_t ciph_offset, comp_offset, ext_offset;
size_t msg_len, ciph_len, sess_len, comp_len, ext_len;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
size_t cookie_offset, cookie_len;
#endif
unsigned char *buf, *p, *ext;
#if defined(MBEDTLS_SSL_RENEGOTIATION)
int renegotiation_info_seen = 0;
#endif
int handshake_failure = 0;
const int *ciphersuites;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
int major, minor;
/* If there is no signature-algorithm extension present,
* we need to fall back to the default values for allowed
* signature-hash pairs. */
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
int sig_hash_alg_ext_present = 0;
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello" ) );
#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
read_record_header:
#endif
/*
* If renegotiating, then the input was read with mbedtls_ssl_read_record(),
* otherwise read it ourselves manually in order to support SSLv2
* ClientHello, which doesn't use the same record layer format.
*/
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE )
#endif
{
if( ( ret = mbedtls_ssl_fetch_input( ssl, 5 ) ) != 0 )
{
/* No alert on a read error. */
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
return( ret );
}
}
buf = ssl->in_hdr;
#if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_STREAM )
#endif
if( ( buf[0] & 0x80 ) != 0 )
return( ssl_parse_client_hello_v2( ssl ) );
#endif
MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, mbedtls_ssl_hdr_len( ssl ) );
/*
* SSLv3/TLS Client Hello
*
* Record layer:
* 0 . 0 message type
* 1 . 2 protocol version
* 3 . 11 DTLS: epoch + record sequence number
* 3 . 4 message length
*/
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, message type: %d",
buf[0] ) );
if( buf[0] != MBEDTLS_SSL_MSG_HANDSHAKE )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, message len.: %d",
( ssl->in_len[0] << 8 ) | ssl->in_len[1] ) );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, protocol version: [%d:%d]",
buf[1], buf[2] ) );
mbedtls_ssl_read_version( &major, &minor, ssl->conf->transport, buf + 1 );
/* According to RFC 5246 Appendix E.1, the version here is typically
* "{03,00}, the lowest version number supported by the client, [or] the
* value of ClientHello.client_version", so the only meaningful check here
* is the major version shouldn't be less than 3 */
if( major < MBEDTLS_SSL_MAJOR_VERSION_3 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/* For DTLS if this is the initial handshake, remember the client sequence
* number to use it in our next message (RFC 6347 4.2.1) */
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM
#if defined(MBEDTLS_SSL_RENEGOTIATION)
&& ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
#endif
)
{
/* Epoch should be 0 for initial handshakes */
if( ssl->in_ctr[0] != 0 || ssl->in_ctr[1] != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
memcpy( ssl->cur_out_ctr + 2, ssl->in_ctr + 2, 6 );
#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
if( mbedtls_ssl_dtls_replay_check( ssl ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "replayed record, discarding" ) );
ssl->next_record_offset = 0;
ssl->in_left = 0;
goto read_record_header;
}
/* No MAC to check yet, so we can update right now */
mbedtls_ssl_dtls_replay_update( ssl );
#endif
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
msg_len = ( ssl->in_len[0] << 8 ) | ssl->in_len[1];
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
{
/* Set by mbedtls_ssl_read_record() */
msg_len = ssl->in_hslen;
}
else
#endif
{
if( msg_len > MBEDTLS_SSL_IN_CONTENT_LEN )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
if( ( ret = mbedtls_ssl_fetch_input( ssl,
mbedtls_ssl_hdr_len( ssl ) + msg_len ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
return( ret );
}
/* Done reading this record, get ready for the next one */
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
ssl->next_record_offset = msg_len + mbedtls_ssl_hdr_len( ssl );
else
#endif
ssl->in_left = 0;
}
buf = ssl->in_msg;
MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, msg_len );
ssl->handshake->update_checksum( ssl, buf, msg_len );
/*
* Handshake layer:
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 DTLS only: message seqence number
* 6 . 8 DTLS only: fragment offset
* 9 . 11 DTLS only: fragment length
*/
if( msg_len < mbedtls_ssl_hs_hdr_len( ssl ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) );
if( buf[0] != MBEDTLS_SSL_HS_CLIENT_HELLO )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
/* We don't support fragmentation of ClientHello (yet?) */
if( buf[1] != 0 ||
msg_len != mbedtls_ssl_hs_hdr_len( ssl ) + ( ( buf[2] << 8 ) | buf[3] ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
{
/*
* Copy the client's handshake message_seq on initial handshakes,
* check sequence number on renego.
*/
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
{
/* This couldn't be done in ssl_prepare_handshake_record() */
unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) |
ssl->in_msg[5];
if( cli_msg_seq != ssl->handshake->in_msg_seq )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message_seq: "
"%d (expected %d)", cli_msg_seq,
ssl->handshake->in_msg_seq ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ssl->handshake->in_msg_seq++;
}
else
#endif
{
unsigned int cli_msg_seq = ( ssl->in_msg[4] << 8 ) |
ssl->in_msg[5];
ssl->handshake->out_msg_seq = cli_msg_seq;
ssl->handshake->in_msg_seq = cli_msg_seq + 1;
}
/*
* For now we don't support fragmentation, so make sure
* fragment_offset == 0 and fragment_length == length
*/
if( ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 ||
memcmp( ssl->in_msg + 1, ssl->in_msg + 9, 3 ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "ClientHello fragmentation not supported" ) );
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
buf += mbedtls_ssl_hs_hdr_len( ssl );
msg_len -= mbedtls_ssl_hs_hdr_len( ssl );
/*
* ClientHello layer:
* 0 . 1 protocol version
* 2 . 33 random bytes (starting with 4 bytes of Unix time)
* 34 . 35 session id length (1 byte)
* 35 . 34+x session id
* 35+x . 35+x DTLS only: cookie length (1 byte)
* 36+x . .. DTLS only: cookie
* .. . .. ciphersuite list length (2 bytes)
* .. . .. ciphersuite list
* .. . .. compression alg. list length (1 byte)
* .. . .. compression alg. list
* .. . .. extensions length (2 bytes, optional)
* .. . .. extensions (optional)
*/
/*
* Minimal length (with everything empty and extensions ommitted) is
* 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can
* read at least up to session id length without worrying.
*/
if( msg_len < 38 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/*
* Check and save the protocol version
*/
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, version", buf, 2 );
mbedtls_ssl_read_version( &ssl->major_ver, &ssl->minor_ver,
ssl->conf->transport, buf );
ssl->handshake->max_major_ver = ssl->major_ver;
ssl->handshake->max_minor_ver = ssl->minor_ver;
if( ssl->major_ver < ssl->conf->min_major_ver ||
ssl->minor_ver < ssl->conf->min_minor_ver )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
" [%d:%d] < [%d:%d]",
ssl->major_ver, ssl->minor_ver,
ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
}
if( ssl->major_ver > ssl->conf->max_major_ver )
{
ssl->major_ver = ssl->conf->max_major_ver;
ssl->minor_ver = ssl->conf->max_minor_ver;
}
else if( ssl->minor_ver > ssl->conf->max_minor_ver )
ssl->minor_ver = ssl->conf->max_minor_ver;
/*
* Save client random (inc. Unix time)
*/
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 2, 32 );
memcpy( ssl->handshake->randbytes, buf + 2, 32 );
/*
* Check the session ID length and save session ID
*/
sess_len = buf[34];
if( sess_len > sizeof( ssl->session_negotiate->id ) ||
sess_len + 34 + 2 > msg_len ) /* 2 for cipherlist length field */
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id", buf + 35, sess_len );
ssl->session_negotiate->id_len = sess_len;
memset( ssl->session_negotiate->id, 0,
sizeof( ssl->session_negotiate->id ) );
memcpy( ssl->session_negotiate->id, buf + 35,
ssl->session_negotiate->id_len );
/*
* Check the cookie length and content
*/
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
{
cookie_offset = 35 + sess_len;
cookie_len = buf[cookie_offset];
if( cookie_offset + 1 + cookie_len + 2 > msg_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, cookie",
buf + cookie_offset + 1, cookie_len );
#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
if( ssl->conf->f_cookie_check != NULL
#if defined(MBEDTLS_SSL_RENEGOTIATION)
&& ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE
#endif
)
{
if( ssl->conf->f_cookie_check( ssl->conf->p_cookie,
buf + cookie_offset + 1, cookie_len,
ssl->cli_id, ssl->cli_id_len ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification failed" ) );
ssl->handshake->verify_cookie_len = 1;
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification passed" ) );
ssl->handshake->verify_cookie_len = 0;
}
}
else
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
{
/* We know we didn't send a cookie, so it should be empty */
if( cookie_len != 0 )
{
/* This may be an attacker's probe, so don't send an alert */
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_MSG( 2, ( "cookie verification skipped" ) );
}
/*
* Check the ciphersuitelist length (will be parsed later)
*/
ciph_offset = cookie_offset + 1 + cookie_len;
}
else
#endif /* MBEDTLS_SSL_PROTO_DTLS */
ciph_offset = 35 + sess_len;
ciph_len = ( buf[ciph_offset + 0] << 8 )
| ( buf[ciph_offset + 1] );
if( ciph_len < 2 ||
ciph_len + 2 + ciph_offset + 1 > msg_len || /* 1 for comp. alg. len */
( ciph_len % 2 ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
buf + ciph_offset + 2, ciph_len );
/*
* Check the compression algorithms length and pick one
*/
comp_offset = ciph_offset + 2 + ciph_len;
comp_len = buf[comp_offset];
if( comp_len < 1 ||
comp_len > 16 ||
comp_len + comp_offset + 1 > msg_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, compression",
buf + comp_offset + 1, comp_len );
ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
#if defined(MBEDTLS_ZLIB_SUPPORT)
for( i = 0; i < comp_len; ++i )
{
if( buf[comp_offset + 1 + i] == MBEDTLS_SSL_COMPRESS_DEFLATE )
{
ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_DEFLATE;
break;
}
}
#endif
/* See comments in ssl_write_client_hello() */
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
#endif
/* Do not parse the extensions if the protocol is SSLv3 */
#if defined(MBEDTLS_SSL_PROTO_SSL3)
if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
{
#endif
/*
* Check the extension length
*/
ext_offset = comp_offset + 1 + comp_len;
if( msg_len > ext_offset )
{
if( msg_len < ext_offset + 2 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ext_len = ( buf[ext_offset + 0] << 8 )
| ( buf[ext_offset + 1] );
if( ( ext_len > 0 && ext_len < 4 ) ||
msg_len != ext_offset + 2 + ext_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
else
ext_len = 0;
ext = buf + ext_offset + 2;
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", ext, ext_len );
while( ext_len != 0 )
{
unsigned int ext_id;
unsigned int ext_size;
if ( ext_len < 4 ) {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
ext_id = ( ( ext[0] << 8 ) | ( ext[1] ) );
ext_size = ( ( ext[2] << 8 ) | ( ext[3] ) );
if( ext_size + 4 > ext_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
switch( ext_id )
{
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
case MBEDTLS_TLS_EXT_SERVERNAME:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ServerName extension" ) );
if( ssl->conf->f_sni == NULL )
break;
ret = ssl_parse_servername_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
case MBEDTLS_TLS_EXT_RENEGOTIATION_INFO:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found renegotiation extension" ) );
#if defined(MBEDTLS_SSL_RENEGOTIATION)
renegotiation_info_seen = 1;
#endif
ret = ssl_parse_renegotiation_info( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
case MBEDTLS_TLS_EXT_SIG_ALG:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
ret = ssl_parse_signature_algorithms_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
sig_hash_alg_ext_present = 1;
break;
#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)
case MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported elliptic curves extension" ) );
ret = ssl_parse_supported_elliptic_curves( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
case MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found supported point formats extension" ) );
ssl->handshake->cli_exts |= MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT;
ret = ssl_parse_supported_point_formats( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C ||
MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
case MBEDTLS_TLS_EXT_ECJPAKE_KKPP:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found ecjpake kkpp extension" ) );
ret = ssl_parse_ecjpake_kkpp( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
case MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found max fragment length extension" ) );
ret = ssl_parse_max_fragment_length_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
case MBEDTLS_TLS_EXT_TRUNCATED_HMAC:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found truncated hmac extension" ) );
ret = ssl_parse_truncated_hmac_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found encrypt then mac extension" ) );
ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
case MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) );
ret = ssl_parse_extended_ms_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
case MBEDTLS_TLS_EXT_SESSION_TICKET:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found session ticket extension" ) );
ret = ssl_parse_session_ticket_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
#if defined(MBEDTLS_SSL_ALPN)
case MBEDTLS_TLS_EXT_ALPN:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found alpn extension" ) );
ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
default:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "unknown extension found: %d (ignoring)",
ext_id ) );
}
ext_len -= 4 + ext_size;
ext += 4 + ext_size;
if( ext_len > 0 && ext_len < 4 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
}
#if defined(MBEDTLS_SSL_PROTO_SSL3)
}
#endif
#if defined(MBEDTLS_SSL_FALLBACK_SCSV)
for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
{
if( p[0] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) &&
p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "received FALLBACK_SCSV" ) );
if( ssl->minor_ver < ssl->conf->max_minor_ver )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
break;
}
}
#endif /* MBEDTLS_SSL_FALLBACK_SCSV */
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
/*
* Try to fall back to default hash SHA1 if the client
* hasn't provided any preferred signature-hash combinations.
*/
if( sig_hash_alg_ext_present == 0 )
{
mbedtls_md_type_t md_default = MBEDTLS_MD_SHA1;
if( mbedtls_ssl_check_sig_hash( ssl, md_default ) != 0 )
md_default = MBEDTLS_MD_NONE;
mbedtls_ssl_sig_hash_set_const_hash( &ssl->handshake->hash_algs, md_default );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
/*
* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
*/
for( i = 0, p = buf + ciph_offset + 2; i < ciph_len; i += 2, p += 2 )
{
if( p[0] == 0 && p[1] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
"during renegotiation" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
#endif
ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
break;
}
}
/*
* Renegotiation security checks
*/
if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION &&
ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
handshake_failure = 1;
}
#if defined(MBEDTLS_SSL_RENEGOTIATION)
else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
ssl->secure_renegotiation == MBEDTLS_SSL_SECURE_RENEGOTIATION &&
renegotiation_info_seen == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
handshake_failure = 1;
}
else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
handshake_failure = 1;
}
else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS &&
ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
renegotiation_info_seen == 1 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation_info extension present (legacy)" ) );
handshake_failure = 1;
}
#endif /* MBEDTLS_SSL_RENEGOTIATION */
if( handshake_failure == 1 )
{
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
/*
* Search for a matching ciphersuite
* (At the end because we need information from the EC-based extensions
* and certificate from the SNI callback triggered by the SNI extension.)
*/
got_common_suite = 0;
ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
ciphersuite_info = NULL;
#if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
for( i = 0; ciphersuites[i] != 0; i++ )
#else
for( i = 0; ciphersuites[i] != 0; i++ )
for( j = 0, p = buf + ciph_offset + 2; j < ciph_len; j += 2, p += 2 )
#endif
{
if( p[0] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
p[1] != ( ( ciphersuites[i] ) & 0xFF ) )
continue;
got_common_suite = 1;
if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
&ciphersuite_info ) ) != 0 )
return( ret );
if( ciphersuite_info != NULL )
goto have_ciphersuite;
}
if( got_common_suite )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
"but none of them usable" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
}
have_ciphersuite:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
ssl->session_negotiate->ciphersuite = ciphersuites[i];
ssl->transform_negotiate->ciphersuite_info = ciphersuite_info;
ssl->state++;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
mbedtls_ssl_recv_flight_completed( ssl );
#endif
/* Debugging-only output for testsuite */
#if defined(MBEDTLS_DEBUG_C) && \
defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
{
mbedtls_pk_type_t sig_alg = mbedtls_ssl_get_ciphersuite_sig_alg( ciphersuite_info );
if( sig_alg != MBEDTLS_PK_NONE )
{
mbedtls_md_type_t md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
sig_alg );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v3, signature_algorithm ext: %d",
mbedtls_ssl_hash_from_md_alg( md_alg ) ) );
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "no hash algorithm for signature algorithm "
"%d - should not happen", sig_alg ) );
}
}
#endif
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello" ) );
return( 0 );
}
#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;
if( ssl->session_negotiate->trunc_hmac == MBEDTLS_SSL_TRUNC_HMAC_DISABLED )
{
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding truncated hmac extension" ) );
*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 mbedtls_ssl_ciphersuite_t *suite = NULL;
const mbedtls_cipher_info_t *cipher = NULL;
if( ssl->session_negotiate->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED ||
ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
{
*olen = 0;
return;
}
/*
* RFC 7366: "If a server receives an encrypt-then-MAC request extension
* from a client and then selects a stream or Authenticated Encryption
* with Associated Data (AEAD) ciphersuite, it MUST NOT send an
* encrypt-then-MAC response extension back to the client."
*/
if( ( suite = mbedtls_ssl_ciphersuite_from_id(
ssl->session_negotiate->ciphersuite ) ) == NULL ||
( cipher = mbedtls_cipher_info_from_type( suite->cipher ) ) == NULL ||
cipher->mode != MBEDTLS_MODE_CBC )
{
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
*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;
if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_DISABLED ||
ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
{
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding extended master secret "
"extension" ) );
*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;
if( ssl->handshake->new_session_ticket == 0 )
{
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding session ticket extension" ) );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SESSION_TICKET ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
static void ssl_write_renegotiation_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
if( ssl->secure_renegotiation != MBEDTLS_SSL_SECURE_RENEGOTIATION )
{
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, secure renegotiation extension" ) );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_RENEGOTIATION_INFO ) & 0xFF );
#if defined(MBEDTLS_SSL_RENEGOTIATION)
if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
{
*p++ = 0x00;
*p++ = ( ssl->verify_data_len * 2 + 1 ) & 0xFF;
*p++ = ssl->verify_data_len * 2 & 0xFF;
memcpy( p, ssl->peer_verify_data, ssl->verify_data_len );
p += ssl->verify_data_len;
memcpy( p, ssl->own_verify_data, ssl->verify_data_len );
p += ssl->verify_data_len;
}
else
#endif /* MBEDTLS_SSL_RENEGOTIATION */
{
*p++ = 0x00;
*p++ = 0x01;
*p++ = 0x00;
}
*olen = p - buf;
}
#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;
if( ssl->session_negotiate->mfl_code == MBEDTLS_SSL_MAX_FRAG_LEN_NONE )
{
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, max_fragment_length extension" ) );
*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->session_negotiate->mfl_code;
*olen = 5;
}
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
static void ssl_write_supported_point_formats_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
((void) ssl);
if( ( ssl->handshake->cli_exts &
MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT ) == 0 )
{
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, supported_point_formats extension" ) );
*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_OUT_CONTENT_LEN;
size_t kkpp_len;
*olen = 0;
/* Skip costly computation if not needed */
if( ssl->transform_negotiate->ciphersuite_info->key_exchange !=
MBEDTLS_KEY_EXCHANGE_ECJPAKE )
return;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, 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 );
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;
}
*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_ALPN )
static void ssl_write_alpn_ext( mbedtls_ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
if( ssl->alpn_chosen == NULL )
{
*olen = 0;
return;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, adding alpn extension" ) );
/*
* 0 . 1 ext identifier
* 2 . 3 ext length
* 4 . 5 protocol list length
* 6 . 6 protocol name length
* 7 . 7+n protocol name
*/
buf[0] = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN >> 8 ) & 0xFF );
buf[1] = (unsigned char)( ( MBEDTLS_TLS_EXT_ALPN ) & 0xFF );
*olen = 7 + strlen( ssl->alpn_chosen );
buf[2] = (unsigned char)( ( ( *olen - 4 ) >> 8 ) & 0xFF );
buf[3] = (unsigned char)( ( ( *olen - 4 ) ) & 0xFF );
buf[4] = (unsigned char)( ( ( *olen - 6 ) >> 8 ) & 0xFF );
buf[5] = (unsigned char)( ( ( *olen - 6 ) ) & 0xFF );
buf[6] = (unsigned char)( ( ( *olen - 7 ) ) & 0xFF );
memcpy( buf + 7, ssl->alpn_chosen, *olen - 7 );
}
#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */
#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl )
{
int ret;
unsigned char *p = ssl->out_msg + 4;
unsigned char *cookie_len_byte;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write hello verify request" ) );
/*
* struct {
* ProtocolVersion server_version;
* opaque cookie<0..2^8-1>;
* } HelloVerifyRequest;
*/
/* The RFC is not clear on this point, but sending the actual negotiated
* version looks like the most interoperable thing to do. */
mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
ssl->conf->transport, p );
MBEDTLS_SSL_DEBUG_BUF( 3, "server version", p, 2 );
p += 2;
/* If we get here, f_cookie_check is not null */
if( ssl->conf->f_cookie_write == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "inconsistent cookie callbacks" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
/* Skip length byte until we know the length */
cookie_len_byte = p++;
if( ( ret = ssl->conf->f_cookie_write( ssl->conf->p_cookie,
&p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN,
ssl->cli_id, ssl->cli_id_len ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "f_cookie_write", ret );
return( ret );
}
*cookie_len_byte = (unsigned char)( p - ( cookie_len_byte + 1 ) );
MBEDTLS_SSL_DEBUG_BUF( 3, "cookie sent", cookie_len_byte + 1, *cookie_len_byte );
ssl->out_msglen = p - ssl->out_msg;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST;
ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT;
if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
return( ret );
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
return( ret );
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) );
return( 0 );
}
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
{
#if defined(MBEDTLS_HAVE_TIME)
mbedtls_time_t t;
#endif
int ret;
size_t olen, ext_len = 0, n;
unsigned char *buf, *p;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello" ) );
#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
ssl->handshake->verify_cookie_len != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "client hello was not authenticated" ) );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
return( ssl_write_hello_verify_request( ssl ) );
}
#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY */
if( ssl->conf->f_rng == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "no RNG provided") );
return( MBEDTLS_ERR_SSL_NO_RNG );
}
/*
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 5 protocol version
* 6 . 9 UNIX time()
* 10 . 37 random bytes
*/
buf = ssl->out_msg;
p = buf + 4;
mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
ssl->conf->transport, p );
p += 2;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen version: [%d:%d]",
buf[4], buf[5] ) );
#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, ( "server 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 );
p += 28;
memcpy( ssl->handshake->randbytes + 32, buf + 6, 32 );
MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, random bytes", buf + 6, 32 );
/*
* Resume is 0 by default, see ssl_handshake_init().
* It may be already set to 1 by ssl_parse_session_ticket_ext().
* If not, try looking up session ID in our cache.
*/
if( ssl->handshake->resume == 0 &&
#if defined(MBEDTLS_SSL_RENEGOTIATION)
ssl->renego_status == MBEDTLS_SSL_INITIAL_HANDSHAKE &&
#endif
ssl->session_negotiate->id_len != 0 &&
ssl->conf->f_get_cache != NULL &&
ssl->conf->f_get_cache( ssl->conf->p_cache, ssl->session_negotiate ) == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "session successfully restored from cache" ) );
ssl->handshake->resume = 1;
}
if( ssl->handshake->resume == 0 )
{
/*
* New session, create a new session id,
* unless we're about to issue a session ticket
*/
ssl->state++;
#if defined(MBEDTLS_HAVE_TIME)
ssl->session_negotiate->start = mbedtls_time( NULL );
#endif
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
if( ssl->handshake->new_session_ticket != 0 )
{
ssl->session_negotiate->id_len = n = 0;
memset( ssl->session_negotiate->id, 0, 32 );
}
else
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
{
ssl->session_negotiate->id_len = n = 32;
if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng, ssl->session_negotiate->id,
n ) ) != 0 )
return( ret );
}
}
else
{
/*
* Resuming a session
*/
n = ssl->session_negotiate->id_len;
ssl->state = MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC;
if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
return( ret );
}
}
/*
* 38 . 38 session id length
* 39 . 38+n session id
* 39+n . 40+n chosen ciphersuite
* 41+n . 41+n chosen compression alg.
* 42+n . 43+n extensions length
* 44+n . 43+n+m extensions
*/
*p++ = (unsigned char) ssl->session_negotiate->id_len;
memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
p += ssl->session_negotiate->id_len;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, session id len.: %d", n ) );
MBEDTLS_SSL_DEBUG_BUF( 3, "server hello, session id", buf + 39, n );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "%s session has been resumed",
ssl->handshake->resume ? "a" : "no" ) );
*p++ = (unsigned char)( ssl->session_negotiate->ciphersuite >> 8 );
*p++ = (unsigned char)( ssl->session_negotiate->ciphersuite );
*p++ = (unsigned char)( ssl->session_negotiate->compression );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, chosen ciphersuite: %s",
mbedtls_ssl_get_ciphersuite_name( ssl->session_negotiate->ciphersuite ) ) );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X",
ssl->session_negotiate->compression ) );
/* Do not write the extensions if the protocol is SSLv3 */
#if defined(MBEDTLS_SSL_PROTO_SSL3)
if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
{
#endif
/*
* First write extensions, then the total length
*/
ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#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
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
ssl_write_session_ticket_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)
if ( mbedtls_ssl_ciphersuite_uses_ec(
mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) )
{
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_ALPN)
ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %d", ext_len ) );
if( ext_len > 0 )
{
*p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ext_len ) & 0xFF );
p += ext_len;
}
#if defined(MBEDTLS_SSL_PROTO_SSL3)
}
#endif
ssl->out_msglen = p - buf;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO;
ret = mbedtls_ssl_write_handshake_msg( ssl );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
return( ret );
}
#if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) && \
!defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) && \
!defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) && \
!defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
!defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)&& \
!defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
{
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->transform_negotiate->ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
ssl->state++;
return( 0 );
}
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
#else
static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->transform_negotiate->ciphersuite_info;
size_t dn_size, total_dn_size; /* excluding length bytes */
size_t ct_len, sa_len; /* including length bytes */
unsigned char *buf, *p;
const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
const mbedtls_x509_crt *crt;
int authmode;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write certificate request" ) );
ssl->state++;
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if( ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET )
authmode = ssl->handshake->sni_authmode;
else
#endif
authmode = ssl->conf->authmode;
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE ||
authmode == MBEDTLS_SSL_VERIFY_NONE )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write certificate request" ) );
return( 0 );
}
/*
* 0 . 0 handshake type
* 1 . 3 handshake length
* 4 . 4 cert type count
* 5 .. m-1 cert types
* m .. m+1 sig alg length (TLS 1.2 only)
* m+1 .. n-1 SignatureAndHashAlgorithms (TLS 1.2 only)
* n .. n+1 length of all DNs
* n+2 .. n+3 length of DN 1
* n+4 .. ... Distinguished Name #1
* ... .. ... length of DN 2, etc.
*/
buf = ssl->out_msg;
p = buf + 4;
/*
* Supported certificate types
*
* ClientCertificateType certificate_types<1..2^8-1>;
* enum { (255) } ClientCertificateType;
*/
ct_len = 0;
#if defined(MBEDTLS_RSA_C)
p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_RSA_SIGN;
#endif
#if defined(MBEDTLS_ECDSA_C)
p[1 + ct_len++] = MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN;
#endif
p[0] = (unsigned char) ct_len++;
p += ct_len;
sa_len = 0;
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
/*
* Add signature_algorithms for verify (TLS 1.2)
*
* SignatureAndHashAlgorithm supported_signature_algorithms<2..2^16-2>;
*
* struct {
* HashAlgorithm hash;
* SignatureAlgorithm signature;
* } SignatureAndHashAlgorithm;
*
* enum { (255) } HashAlgorithm;
* enum { (255) } SignatureAlgorithm;
*/
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
{
const int *cur;
/*
* Supported signature algorithms
*/
for( cur = ssl->conf->sig_hashes; *cur != MBEDTLS_MD_NONE; cur++ )
{
unsigned char hash = mbedtls_ssl_hash_from_md_alg( *cur );
if( MBEDTLS_SSL_HASH_NONE == hash || mbedtls_ssl_set_calc_verify_md( ssl, hash ) )
continue;
#if defined(MBEDTLS_RSA_C)
p[2 + sa_len++] = hash;
p[2 + sa_len++] = MBEDTLS_SSL_SIG_RSA;
#endif
#if defined(MBEDTLS_ECDSA_C)
p[2 + sa_len++] = hash;
p[2 + sa_len++] = MBEDTLS_SSL_SIG_ECDSA;
#endif
}
p[0] = (unsigned char)( sa_len >> 8 );
p[1] = (unsigned char)( sa_len );
sa_len += 2;
p += sa_len;
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
/*
* DistinguishedName certificate_authorities<0..2^16-1>;
* opaque DistinguishedName<1..2^16-1>;
*/
p += 2;
total_dn_size = 0;
if( ssl->conf->cert_req_ca_list == MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED )
{
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if( ssl->handshake->sni_ca_chain != NULL )
crt = ssl->handshake->sni_ca_chain;
else
#endif
crt = ssl->conf->ca_chain;
while( crt != NULL && crt->version != 0 )
{
dn_size = crt->subject_raw.len;
if( end < p ||
(size_t)( end - p ) < dn_size ||
(size_t)( end - p ) < 2 + dn_size )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "skipping CAs: buffer too short" ) );
break;
}
*p++ = (unsigned char)( dn_size >> 8 );
*p++ = (unsigned char)( dn_size );
memcpy( p, crt->subject_raw.p, dn_size );
p += dn_size;
MBEDTLS_SSL_DEBUG_BUF( 3, "requested DN", p - dn_size, dn_size );
total_dn_size += 2 + dn_size;
crt = crt->next;
}
}
ssl->out_msglen = p - buf;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_CERTIFICATE_REQUEST;
ssl->out_msg[4 + ct_len + sa_len] = (unsigned char)( total_dn_size >> 8 );
ssl->out_msg[5 + ct_len + sa_len] = (unsigned char)( total_dn_size );
ret = mbedtls_ssl_write_handshake_msg( ssl );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
return( ret );
}
#endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
static int ssl_get_ecdh_params_from_cert( mbedtls_ssl_context *ssl )
{
int ret;
if( ! mbedtls_pk_can_do( mbedtls_ssl_own_key( ssl ), MBEDTLS_PK_ECKEY ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "server key not ECDH capable" ) );
return( MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH );
}
if( ( ret = mbedtls_ecdh_get_params( &ssl->handshake->ecdh_ctx,
mbedtls_pk_ec( *mbedtls_ssl_own_key( ssl ) ),
MBEDTLS_ECDH_OURS ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ecdh_get_params" ), ret );
return( ret );
}
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||
MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) && \
defined(MBEDTLS_SSL_ASYNC_PRIVATE)
static int ssl_resume_server_key_exchange( mbedtls_ssl_context *ssl,
size_t *signature_len )
{
/* Append the signature to ssl->out_msg, leaving 2 bytes for the
* signature length which will be added in ssl_write_server_key_exchange
* after the call to ssl_prepare_server_key_exchange.
* ssl_write_server_key_exchange also takes care of incrementing
* ssl->out_msglen. */
unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2;
size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN
- sig_start );
int ret = ssl->conf->f_async_resume( ssl,
sig_start, signature_len, sig_max_len );
if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
{
ssl->handshake->async_in_progress = 0;
mbedtls_ssl_set_async_operation_data( ssl, NULL );
}
MBEDTLS_SSL_DEBUG_RET( 2, "ssl_resume_server_key_exchange", ret );
return( ret );
}
#endif /* defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) &&
defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
/* Prepare the ServerKeyExchange message, up to and including
* calculating the signature if any, but excluding formatting the
* signature and sending the message. */
static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
size_t *signature_len )
{
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->transform_negotiate->ciphersuite_info;
#if defined(MBEDTLS_KEY_EXCHANGE__SOME_PFS__ENABLED)
#if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
unsigned char *dig_signed = NULL;
#endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
#endif /* MBEDTLS_KEY_EXCHANGE__SOME_PFS__ENABLED */
(void) ciphersuite_info; /* unused in some configurations */
#if !defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
(void) signature_len;
#endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
ssl->out_msglen = 4; /* header (type:1, length:3) to be written later */
/*
*
* Part 1: Provide key exchange parameters for chosen ciphersuite.
*
*/
/*
* - ECJPAKE key exchanges
*/
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
{
int ret;
size_t len = 0;
ret = mbedtls_ecjpake_write_round_two(
&ssl->handshake->ecjpake_ctx,
ssl->out_msg + ssl->out_msglen,
MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len,
ssl->conf->f_rng, ssl->conf->p_rng );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_write_round_two", ret );
return( ret );
}
ssl->out_msglen += len;
}
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
/*
* For (EC)DHE key exchanges with PSK, parameters are prefixed by support
* identity hint (RFC 4279, Sec. 3). Until someone needs this feature,
* we use empty support identity hints here.
**/
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
{
ssl->out_msg[ssl->out_msglen++] = 0x00;
ssl->out_msg[ssl->out_msglen++] = 0x00;
}
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
/*
* - DHE key exchanges
*/
#if defined(MBEDTLS_KEY_EXCHANGE__SOME__DHE_ENABLED)
if( mbedtls_ssl_ciphersuite_uses_dhe( ciphersuite_info ) )
{
int ret;
size_t len = 0;
if( ssl->conf->dhm_P.p == NULL || ssl->conf->dhm_G.p == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "no DH parameters set" ) );
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
}
/*
* Ephemeral DH parameters:
*
* struct {
* opaque dh_p<1..2^16-1>;
* opaque dh_g<1..2^16-1>;
* opaque dh_Ys<1..2^16-1>;
* } ServerDHParams;
*/
if( ( ret = mbedtls_dhm_set_group( &ssl->handshake->dhm_ctx,
&ssl->conf->dhm_P,
&ssl->conf->dhm_G ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_set_group", ret );
return( ret );
}
if( ( ret = mbedtls_dhm_make_params(
&ssl->handshake->dhm_ctx,
(int) mbedtls_mpi_size( &ssl->handshake->dhm_ctx.P ),
ssl->out_msg + ssl->out_msglen, &len,
ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_make_params", ret );
return( ret );
}
#if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
dig_signed = ssl->out_msg + ssl->out_msglen;
#endif
ssl->out_msglen += len;
MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: X ", &ssl->handshake->dhm_ctx.X );
MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: P ", &ssl->handshake->dhm_ctx.P );
MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: G ", &ssl->handshake->dhm_ctx.G );
MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GX", &ssl->handshake->dhm_ctx.GX );
}
#endif /* MBEDTLS_KEY_EXCHANGE__SOME__DHE_ENABLED */
/*
* - ECDHE key exchanges
*/
#if defined(MBEDTLS_KEY_EXCHANGE__SOME__ECDHE_ENABLED)
if( mbedtls_ssl_ciphersuite_uses_ecdhe( ciphersuite_info ) )
{
/*
* Ephemeral ECDH parameters:
*
* struct {
* ECParameters curve_params;
* ECPoint public;
* } ServerECDHParams;
*/
const mbedtls_ecp_curve_info **curve = NULL;
const mbedtls_ecp_group_id *gid;
int ret;
size_t len = 0;
/* Match our preference list against the offered curves */
for( gid = ssl->conf->curve_list; *gid != MBEDTLS_ECP_DP_NONE; gid++ )
for( curve = ssl->handshake->curves; *curve != NULL; curve++ )
if( (*curve)->grp_id == *gid )
goto curve_matching_done;
curve_matching_done:
if( curve == NULL || *curve == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "no matching curve for ECDHE" ) );
return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
}
MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDHE curve: %s", (*curve)->name ) );
if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx,
(*curve)->grp_id ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecp_group_load", ret );
return( ret );
}
if( ( ret = mbedtls_ecdh_make_params(
&ssl->handshake->ecdh_ctx, &len,
ssl->out_msg + ssl->out_msglen,
MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen,
ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_params", ret );
return( ret );
}
#if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
dig_signed = ssl->out_msg + ssl->out_msglen;
#endif
ssl->out_msglen += len;
MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_Q );
}
#endif /* MBEDTLS_KEY_EXCHANGE__SOME__ECDHE_ENABLED */
/*
*
* Part 2: For key exchanges involving the server signing the
* exchange parameters, compute and add the signature here.
*
*/
#if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
if( mbedtls_ssl_ciphersuite_uses_server_signature( ciphersuite_info ) )
{
size_t dig_signed_len = ssl->out_msg + ssl->out_msglen - dig_signed;
size_t hashlen = 0;
unsigned char hash[MBEDTLS_MD_MAX_SIZE];
int ret;
/*
* 2.1: Choose hash algorithm:
* A: For TLS 1.2, obey signature-hash-algorithm extension
* to choose appropriate hash.
* B: For SSL3, TLS1.0, TLS1.1 and ECDHE_ECDSA, use SHA1
* (RFC 4492, Sec. 5.4)
* C: Otherwise, use MD5 + SHA1 (RFC 4346, Sec. 7.4.3)
*/
mbedtls_md_type_t md_alg;
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
mbedtls_pk_type_t sig_alg =
mbedtls_ssl_get_ciphersuite_sig_pk_alg( ciphersuite_info );
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
{
/* A: For TLS 1.2, obey signature-hash-algorithm extension
* (RFC 5246, Sec. 7.4.1.4.1). */
if( sig_alg == MBEDTLS_PK_NONE ||
( md_alg = mbedtls_ssl_sig_hash_set_find( &ssl->handshake->hash_algs,
sig_alg ) ) == MBEDTLS_MD_NONE )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
/* (... because we choose a cipher suite
* only if there is a matching hash.) */
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
}
else
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
defined(MBEDTLS_SSL_PROTO_TLS1_1)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA )
{
/* B: Default hash SHA1 */
md_alg = MBEDTLS_MD_SHA1;
}
else
#endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
MBEDTLS_SSL_PROTO_TLS1_1 */
{
/* C: MD5 + SHA1 */
md_alg = MBEDTLS_MD_NONE;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "pick hash algorithm %d for signing", md_alg ) );
/*
* 2.2: Compute the hash to be signed
*/
#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
defined(MBEDTLS_SSL_PROTO_TLS1_1)
if( md_alg == MBEDTLS_MD_NONE )
{
hashlen = 36;
ret = mbedtls_ssl_get_key_exchange_md_ssl_tls( ssl, hash,
dig_signed,
dig_signed_len );
if( ret != 0 )
return( ret );
}
else
#endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
MBEDTLS_SSL_PROTO_TLS1_1 */
#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
defined(MBEDTLS_SSL_PROTO_TLS1_2)
if( md_alg != MBEDTLS_MD_NONE )
{
ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, &hashlen,
dig_signed,
dig_signed_len,
md_alg );
if( ret != 0 )
return( ret );
}
else
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
MBEDTLS_SSL_PROTO_TLS1_2 */
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "parameters hash", hash, hashlen );
/*
* 2.3: Compute and add the signature
*/
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
{
/*
* For TLS 1.2, we need to specify signature and hash algorithm
* explicitly through a prefix to the signature.
*
* struct {
* HashAlgorithm hash;
* SignatureAlgorithm signature;
* } SignatureAndHashAlgorithm;
*
* struct {
* SignatureAndHashAlgorithm algorithm;
* opaque signature<0..2^16-1>;
* } DigitallySigned;
*
*/
ssl->out_msg[ssl->out_msglen++] =
mbedtls_ssl_hash_from_md_alg( md_alg );
ssl->out_msg[ssl->out_msglen++] =
mbedtls_ssl_sig_from_pk_alg( sig_alg );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
if( ssl->conf->f_async_sign_start != NULL )
{
ret = ssl->conf->f_async_sign_start( ssl,
mbedtls_ssl_own_cert( ssl ),
md_alg, hash, hashlen );
switch( ret )
{
case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
/* act as if f_async_sign was null */
break;
case 0:
ssl->handshake->async_in_progress = 1;
return( ssl_resume_server_key_exchange( ssl, signature_len ) );
case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
ssl->handshake->async_in_progress = 1;
return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
default:
MBEDTLS_SSL_DEBUG_RET( 1, "f_async_sign_start", ret );
return( ret );
}
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
if( mbedtls_ssl_own_key( ssl ) == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no private key" ) );
return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
/* Append the signature to ssl->out_msg, leaving 2 bytes for the
* signature length which will be added in ssl_write_server_key_exchange
* after the call to ssl_prepare_server_key_exchange.
* ssl_write_server_key_exchange also takes care of incrementing
* ssl->out_msglen. */
if( ( ret = mbedtls_pk_sign( mbedtls_ssl_own_key( ssl ),
md_alg, hash, hashlen,
ssl->out_msg + ssl->out_msglen + 2,
signature_len,
ssl->conf->f_rng,
ssl->conf->p_rng ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_sign", ret );
return( ret );
}
}
#endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
return( 0 );
}
/* Prepare the ServerKeyExchange message and send it. For ciphersuites
* that do not include a ServerKeyExchange message, do nothing. Either
* way, if successful, move on to the next step in the SSL state
* machine. */
static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl )
{
int ret;
size_t signature_len = 0;
#if defined(MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED)
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->transform_negotiate->ciphersuite_info;
#endif /* MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED */
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server key exchange" ) );
#if defined(MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED)
/* Extract static ECDH parameters and abort if ServerKeyExchange
* is not needed. */
if( mbedtls_ssl_ciphersuite_no_pfs( ciphersuite_info ) )
{
/* For suites involving ECDH, extract DH parameters
* from certificate at this point. */
#if defined(MBEDTLS_KEY_EXCHANGE__SOME__ECDH_ENABLED)
if( mbedtls_ssl_ciphersuite_uses_ecdh( ciphersuite_info ) )
{
ssl_get_ecdh_params_from_cert( ssl );
}
#endif /* MBEDTLS_KEY_EXCHANGE__SOME__ECDH_ENABLED */
/* Key exchanges not involving ephemeral keys don't use
* ServerKeyExchange, so end here. */
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip write server key exchange" ) );
ssl->state++;
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE__SOME_NON_PFS__ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) && \
defined(MBEDTLS_SSL_ASYNC_PRIVATE)
/* If we have already prepared the message and there is an ongoing
* signature operation, resume signing. */
if( ssl->handshake->async_in_progress != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming signature operation" ) );
ret = ssl_resume_server_key_exchange( ssl, &signature_len );
}
else
#endif /* defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) &&
defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
{
/* ServerKeyExchange is needed. Prepare the message. */
ret = ssl_prepare_server_key_exchange( ssl, &signature_len );
}
if( ret != 0 )
{
/* If we're starting to write a new message, set ssl->out_msglen
* to 0. But if we're resuming after an asynchronous message,
* out_msglen is the amount of data written so far and mst be
* preserved. */
if( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange (pending)" ) );
else
ssl->out_msglen = 0;
return( ret );
}
/* If there is a signature, write its length.
* ssl_prepare_server_key_exchange already wrote the signature
* itself at its proper place in the output buffer. */
#if defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED)
if( signature_len != 0 )
{
ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len >> 8 );
ssl->out_msg[ssl->out_msglen++] = (unsigned char)( signature_len );
MBEDTLS_SSL_DEBUG_BUF( 3, "my signature",
ssl->out_msg + ssl->out_msglen,
signature_len );
/* Skip over the already-written signature */
ssl->out_msglen += signature_len;
}
#endif /* MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED */
/* Add header and send. */
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE;
ssl->state++;
if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
return( ret );
}
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server key exchange" ) );
return( 0 );
}
static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl )
{
int ret;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write server hello done" ) );
ssl->out_msglen = 4;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO_DONE;
ssl->state++;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
mbedtls_ssl_send_flight_completed( ssl );
#endif
if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
return( ret );
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
return( ret );
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
return( 0 );
}
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char **p,
const unsigned char *end )
{
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
size_t n;
/*
* Receive G^Y mod P, premaster = (G^Y)^X mod P
*/
if( *p + 2 > end )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
n = ( (*p)[0] << 8 ) | (*p)[1];
*p += 2;
if( *p + n > end )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ( ret = mbedtls_dhm_read_public( &ssl->handshake->dhm_ctx, *p, n ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_read_public", ret );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
}
*p += n;
MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
return( ret );
}
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
static int ssl_resume_decrypt_pms( mbedtls_ssl_context *ssl,
unsigned char *peer_pms,
size_t *peer_pmslen,
size_t peer_pmssize )
{
int ret = ssl->conf->f_async_resume( ssl,
peer_pms, peer_pmslen, peer_pmssize );
if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
{
ssl->handshake->async_in_progress = 0;
mbedtls_ssl_set_async_operation_data( ssl, NULL );
}
MBEDTLS_SSL_DEBUG_RET( 2, "ssl_decrypt_encrypted_pms", ret );
return( ret );
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
static int ssl_decrypt_encrypted_pms( mbedtls_ssl_context *ssl,
const unsigned char *p,
const unsigned char *end,
unsigned char *peer_pms,
size_t *peer_pmslen,
size_t peer_pmssize )
{
int ret;
mbedtls_pk_context *private_key = mbedtls_ssl_own_key( ssl );
mbedtls_pk_context *public_key = &mbedtls_ssl_own_cert( ssl )->pk;
size_t len = mbedtls_pk_get_len( public_key );
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
/* If we have already started decoding the message and there is an ongoing
* decryption operation, resume signing. */
if( ssl->handshake->async_in_progress != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "resuming decryption operation" ) );
return( ssl_resume_decrypt_pms( ssl,
peer_pms, peer_pmslen, peer_pmssize ) );
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
/*
* Prepare to decrypt the premaster using own private RSA key
*/
#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
defined(MBEDTLS_SSL_PROTO_TLS1_2)
if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
{
if ( p + 2 > end ) {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( *p++ != ( ( len >> 8 ) & 0xFF ) ||
*p++ != ( ( len ) & 0xFF ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
}
#endif
if( p + len != end )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
/*
* Decrypt the premaster secret
*/
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
if( ssl->conf->f_async_decrypt_start != NULL )
{
ret = ssl->conf->f_async_decrypt_start( ssl,
mbedtls_ssl_own_cert( ssl ),
p, len );
switch( ret )
{
case MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH:
/* act as if f_async_decrypt_start was null */
break;
case 0:
ssl->handshake->async_in_progress = 1;
return( ssl_resume_decrypt_pms( ssl,
peer_pms,
peer_pmslen,
peer_pmssize ) );
case MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS:
ssl->handshake->async_in_progress = 1;
return( MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS );
default:
MBEDTLS_SSL_DEBUG_RET( 1, "f_async_decrypt_start", ret );
return( ret );
}
}
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
if( ! mbedtls_pk_can_do( private_key, MBEDTLS_PK_RSA ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no RSA private key" ) );
return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
ret = mbedtls_pk_decrypt( private_key, p, len,
peer_pms, peer_pmslen, peer_pmssize,
ssl->conf->f_rng, ssl->conf->p_rng );
return( ret );
}
static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
const unsigned char *p,
const unsigned char *end,
size_t pms_offset )
{
int ret;
unsigned char *pms = ssl->handshake->premaster + pms_offset;
unsigned char ver[2];
unsigned char fake_pms[48], peer_pms[48];
unsigned char mask;
size_t i, peer_pmslen;
unsigned int diff;
/* In case of a failure in decryption, the decryption may write less than
* 2 bytes of output, but we always read the first two bytes. It doesn't
* matter in the end because diff will be nonzero in that case due to
* peer_pmslen being less than 48, and we only care whether diff is 0.
* But do initialize peer_pms for robustness anyway. This also makes
* memory analyzers happy (don't access uninitialized memory, even
* if it's an unsigned char). */
peer_pms[0] = peer_pms[1] = ~0;
ret = ssl_decrypt_encrypted_pms( ssl, p, end,
peer_pms,
&peer_pmslen,
sizeof( peer_pms ) );
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
if ( ret == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
return( ret );
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
mbedtls_ssl_write_version( ssl->handshake->max_major_ver,
ssl->handshake->max_minor_ver,
ssl->conf->transport, ver );
/* Avoid data-dependent branches while checking for invalid
* padding, to protect against timing-based Bleichenbacher-type
* attacks. */
diff = (unsigned int) ret;
diff |= peer_pmslen ^ 48;
diff |= peer_pms[0] ^ ver[0];
diff |= peer_pms[1] ^ ver[1];
/* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
/* MSVC has a warning about unary minus on unsigned, but this is
* well-defined and precisely what we want to do here */
#if defined(_MSC_VER)
#pragma warning( push )
#pragma warning( disable : 4146 )
#endif
mask = - ( ( diff | - diff ) >> ( sizeof( unsigned int ) * 8 - 1 ) );
#if defined(_MSC_VER)
#pragma warning( pop )
#endif
/*
* Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding
* must not cause the connection to end immediately; instead, send a
* bad_record_mac later in the handshake.
* To protect against timing-based variants of the attack, we must
* not have any branch that depends on whether the decryption was
* successful. In particular, always generate the fake premaster secret,
* regardless of whether it will ultimately influence the output or not.
*/
ret = ssl->conf->f_rng( ssl->conf->p_rng, fake_pms, sizeof( fake_pms ) );
if( ret != 0 )
{
/* It's ok to abort on an RNG failure, since this does not reveal
* anything about the RSA decryption. */
return( ret );
}
#if defined(MBEDTLS_SSL_DEBUG_ALL)
if( diff != 0 )
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
#endif
if( sizeof( ssl->handshake->premaster ) < pms_offset ||
sizeof( ssl->handshake->premaster ) - pms_offset < 48 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
ssl->handshake->pmslen = 48;
/* Set pms to either the true or the fake PMS, without
* data-dependent branches. */
for( i = 0; i < ssl->handshake->pmslen; i++ )
pms[i] = ( mask & fake_pms[i] ) | ( (~mask) & peer_pms[i] );
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned char **p,
const unsigned char *end )
{
int ret = 0;
size_t n;
if( ssl->conf->f_psk == NULL &&
( ssl->conf->psk == NULL || ssl->conf->psk_identity == NULL ||
ssl->conf->psk_identity_len == 0 || ssl->conf->psk_len == 0 ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no pre-shared key" ) );
return( MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED );
}
/*
* Receive client pre-shared key identity name
*/
if( end - *p < 2 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
n = ( (*p)[0] << 8 ) | (*p)[1];
*p += 2;
if( n < 1 || n > 65535 || n > (size_t) ( end - *p ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ssl->conf->f_psk != NULL )
{
if( ssl->conf->f_psk( ssl->conf->p_psk, ssl, *p, n ) != 0 )
ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
}
else
{
/* Identity is not a big secret since clients send it in the clear,
* but treat it carefully anyway, just in case */
if( n != ssl->conf->psk_identity_len ||
mbedtls_ssl_safer_memcmp( ssl->conf->psk_identity, *p, n ) != 0 )
{
ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
}
}
if( ret == MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY )
{
MBEDTLS_SSL_DEBUG_BUF( 3, "Unknown PSK identity", *p, n );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY );
return( MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY );
}
*p += n;
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */
static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl )
{
int ret;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
unsigned char *p, *end;
ciphersuite_info = ssl->transform_negotiate->ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client key exchange" ) );
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE) && \
( defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) )
if( ( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA ) &&
( ssl->handshake->async_in_progress != 0 ) )
{
/* We've already read a record and there is an asynchronous
* operation in progress to decrypt it. So skip reading the
* record. */
MBEDTLS_SSL_DEBUG_MSG( 3, ( "will resume decryption of previously-read record" ) );
}
else
#endif
if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret );
}
p = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
end = ssl->in_msg + ssl->in_hslen;
if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_RSA )
{
if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
return( ret );
}
if( p != end )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ( ret = mbedtls_dhm_calc_secret( &ssl->handshake->dhm_ctx,
ssl->handshake->premaster,
MBEDTLS_PREMASTER_SIZE,
&ssl->handshake->pmslen,
ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_dhm_calc_secret", ret );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
}
MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: K ", &ssl->handshake->dhm_ctx.K );
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_RSA ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_RSA ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA )
{
if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
p, end - p) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
}
MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_QP );
if( ( ret = mbedtls_ecdh_calc_secret( &ssl->handshake->ecdh_ctx,
&ssl->handshake->pmslen,
ssl->handshake->premaster,
MBEDTLS_MPI_MAX_SIZE,
ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_calc_secret", ret );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS );
}
MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_Z );
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK )
{
if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
return( ret );
}
if( p != end )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
ciphersuite_info->key_exchange ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
return( ret );
}
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK )
{
#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
if ( ssl->handshake->async_in_progress != 0 )
{
/* There is an asynchronous operation in progress to
* decrypt the encrypted premaster secret, so skip
* directly to resuming this operation. */
MBEDTLS_SSL_DEBUG_MSG( 3, ( "PSK identity already parsed" ) );
/* Update p to skip the PSK identity. ssl_parse_encrypted_pms
* won't actually use it, but maintain p anyway for robustness. */
p += ssl->conf->psk_identity_len + 2;
}
else
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
return( ret );
}
if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 2 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_encrypted_pms" ), ret );
return( ret );
}
if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
ciphersuite_info->key_exchange ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
return( ret );
}
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK )
{
if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
return( ret );
}
if( ( ret = ssl_parse_client_dh_public( ssl, &p, end ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_dh_public" ), ret );
return( ret );
}
if( p != end )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
}
if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
ciphersuite_info->key_exchange ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
return( ret );
}
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK )
{
if( ( ret = ssl_parse_client_psk_identity( ssl, &p, end ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_client_psk_identity" ), ret );
return( ret );
}
if( ( ret = mbedtls_ecdh_read_public( &ssl->handshake->ecdh_ctx,
p, end - p ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_read_public", ret );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP );
}
MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
MBEDTLS_DEBUG_ECDH_QP );
if( ( ret = mbedtls_ssl_psk_derive_premaster( ssl,
ciphersuite_info->key_exchange ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_psk_derive_premaster", ret );
return( ret );
}
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA )
{
if( ( ret = ssl_parse_encrypted_pms( ssl, p, end, 0 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_parse_parse_encrypted_pms_secret" ), ret );
return( ret );
}
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_RSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
{
ret = mbedtls_ecjpake_read_round_two( &ssl->handshake->ecjpake_ctx,
p, end - p );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_read_round_two", ret );
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
ret = mbedtls_ecjpake_derive_secret( &ssl->handshake->ecjpake_ctx,
ssl->handshake->premaster, 32, &ssl->handshake->pmslen,
ssl->conf->f_rng, ssl->conf->p_rng );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecjpake_derive_secret", ret );
return( ret );
}
}
else
#endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
if( ( ret = mbedtls_ssl_derive_keys( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_derive_keys", ret );
return( ret );
}
ssl->state++;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client key exchange" ) );
return( 0 );
}
#if !defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) && \
!defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) && \
!defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) && \
!defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) && \
!defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)&& \
!defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
{
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->transform_negotiate->ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
ssl->state++;
return( 0 );
}
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
#else
static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
size_t i, sig_len;
unsigned char hash[48];
unsigned char *hash_start = hash;
size_t hashlen;
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
mbedtls_pk_type_t pk_alg;
#endif
mbedtls_md_type_t md_alg;
const mbedtls_ssl_ciphersuite_t *ciphersuite_info =
ssl->transform_negotiate->ciphersuite_info;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_RSA_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECDHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_DHE_PSK ||
ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_ECJPAKE ||
ssl->session_negotiate->peer_cert == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate verify" ) );
ssl->state++;
return( 0 );
}
/* Read the message without adding it to the checksum */
ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
if( 0 != ret )
{
MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
return( ret );
}
ssl->state++;
/* Process the message contents */
if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
ssl->in_msg[0] != MBEDTLS_SSL_HS_CERTIFICATE_VERIFY )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
i = mbedtls_ssl_hs_hdr_len( ssl );
/*
* struct {
* SignatureAndHashAlgorithm algorithm; -- TLS 1.2 only
* opaque signature<0..2^16-1>;
* } DigitallySigned;
*/
#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
defined(MBEDTLS_SSL_PROTO_TLS1_1)
if( ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_3 )
{
md_alg = MBEDTLS_MD_NONE;
hashlen = 36;
/* For ECDSA, use SHA-1, not MD-5 + SHA-1 */
if( mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk,
MBEDTLS_PK_ECDSA ) )
{
hash_start += 16;
hashlen -= 16;
md_alg = MBEDTLS_MD_SHA1;
}
}
else
#endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 ||
MBEDTLS_SSL_PROTO_TLS1_1 */
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
{
if( i + 2 > ssl->in_hslen )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
/*
* Hash
*/
md_alg = mbedtls_ssl_md_alg_from_hash( ssl->in_msg[i] );
if( md_alg == MBEDTLS_MD_NONE || mbedtls_ssl_set_calc_verify_md( ssl, ssl->in_msg[i] ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
" for verify message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
#if !defined(MBEDTLS_MD_SHA1)
if( MBEDTLS_MD_SHA1 == md_alg )
hash_start += 16;
#endif
/* Info from md_alg will be used instead */
hashlen = 0;
i++;
/*
* Signature
*/
if( ( pk_alg = mbedtls_ssl_pk_alg_from_sig( ssl->in_msg[i] ) )
== MBEDTLS_PK_NONE )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "peer not adhering to requested sig_alg"
" for verify message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
/*
* Check the certificate's key type matches the signature alg
*/
if( ! mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, pk_alg ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "sig_alg doesn't match cert key" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
i++;
}
else
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
if( i + 2 > ssl->in_hslen )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
sig_len = ( ssl->in_msg[i] << 8 ) | ssl->in_msg[i+1];
i += 2;
if( i + sig_len != ssl->in_hslen )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate verify message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY );
}
/* Calculate hash and verify signature */
ssl->handshake->calc_verify( ssl, hash );
if( ( ret = mbedtls_pk_verify( &ssl->session_negotiate->peer_cert->pk,
md_alg, hash_start, hashlen,
ssl->in_msg + i, sig_len ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify", ret );
return( ret );
}
mbedtls_ssl_update_handshake_status( ssl );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
return( ret );
}
#endif /* !MBEDTLS_KEY_EXCHANGE_RSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED &&
!MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl )
{
int ret;
size_t tlen;
uint32_t lifetime;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write new session ticket" ) );
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_NEW_SESSION_TICKET;
/*
* struct {
* uint32 ticket_lifetime_hint;
* opaque ticket<0..2^16-1>;
* } NewSessionTicket;
*
* 4 . 7 ticket_lifetime_hint (0 = unspecified)
* 8 . 9 ticket_len (n)
* 10 . 9+n ticket content
*/
if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket,
ssl->session_negotiate,
ssl->out_msg + 10,
ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
&tlen, &lifetime ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_write", ret );
tlen = 0;
}
ssl->out_msg[4] = ( lifetime >> 24 ) & 0xFF;
ssl->out_msg[5] = ( lifetime >> 16 ) & 0xFF;
ssl->out_msg[6] = ( lifetime >> 8 ) & 0xFF;
ssl->out_msg[7] = ( lifetime ) & 0xFF;
ssl->out_msg[8] = (unsigned char)( ( tlen >> 8 ) & 0xFF );
ssl->out_msg[9] = (unsigned char)( ( tlen ) & 0xFF );
ssl->out_msglen = 10 + tlen;
/*
* Morally equivalent to updating ssl->state, but NewSessionTicket and
* ChangeCipherSpec share the same state.
*/
ssl->handshake->new_session_ticket = 0;
if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
return( ret );
}
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write new session ticket" ) );
return( 0 );
}
#endif /* MBEDTLS_SSL_SESSION_TICKETS */
/*
* SSL handshake -- server side -- single step
*/
int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl )
{
int ret = 0;
if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER || ssl->handshake == NULL )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "server state: %d", ssl->state ) );
if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
return( ret );
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
{
if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
return( ret );
}
#endif /* MBEDTLS_SSL_PROTO_DTLS */
switch( ssl->state )
{
case MBEDTLS_SSL_HELLO_REQUEST:
ssl->state = MBEDTLS_SSL_CLIENT_HELLO;
break;
/*
* <== ClientHello
*/
case MBEDTLS_SSL_CLIENT_HELLO:
ret = ssl_parse_client_hello( ssl );
break;
#if defined(MBEDTLS_SSL_PROTO_DTLS)
case MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT:
return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED );
#endif
/*
* ==> ServerHello
* Certificate
* ( ServerKeyExchange )
* ( CertificateRequest )
* ServerHelloDone
*/
case MBEDTLS_SSL_SERVER_HELLO:
ret = ssl_write_server_hello( ssl );
break;
case MBEDTLS_SSL_SERVER_CERTIFICATE:
ret = mbedtls_ssl_write_certificate( ssl );
break;
case MBEDTLS_SSL_SERVER_KEY_EXCHANGE:
ret = ssl_write_server_key_exchange( ssl );
break;
case MBEDTLS_SSL_CERTIFICATE_REQUEST:
ret = ssl_write_certificate_request( ssl );
break;
case MBEDTLS_SSL_SERVER_HELLO_DONE:
ret = ssl_write_server_hello_done( ssl );
break;
/*
* <== ( Certificate/Alert )
* ClientKeyExchange
* ( CertificateVerify )
* ChangeCipherSpec
* Finished
*/
case MBEDTLS_SSL_CLIENT_CERTIFICATE:
ret = mbedtls_ssl_parse_certificate( ssl );
break;
case MBEDTLS_SSL_CLIENT_KEY_EXCHANGE:
ret = ssl_parse_client_key_exchange( ssl );
break;
case MBEDTLS_SSL_CERTIFICATE_VERIFY:
ret = ssl_parse_certificate_verify( ssl );
break;
case MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC:
ret = mbedtls_ssl_parse_change_cipher_spec( ssl );
break;
case MBEDTLS_SSL_CLIENT_FINISHED:
ret = mbedtls_ssl_parse_finished( ssl );
break;
/*
* ==> ( NewSessionTicket )
* ChangeCipherSpec
* Finished
*/
case MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC:
#if defined(MBEDTLS_SSL_SESSION_TICKETS)
if( ssl->handshake->new_session_ticket != 0 )
ret = ssl_write_new_session_ticket( ssl );
else
#endif
ret = mbedtls_ssl_write_change_cipher_spec( ssl );
break;
case MBEDTLS_SSL_SERVER_FINISHED:
ret = mbedtls_ssl_write_finished( ssl );
break;
case MBEDTLS_SSL_FLUSH_BUFFERS:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake: done" ) );
ssl->state = MBEDTLS_SSL_HANDSHAKE_WRAPUP;
break;
case MBEDTLS_SSL_HANDSHAKE_WRAPUP:
mbedtls_ssl_handshake_wrapup( ssl );
break;
default:
MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
}
return( ret );
}
#endif /* MBEDTLS_SSL_SRV_C */
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