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ssl_srv.c
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ssl_srv.c
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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 );
}