Drop support for parsing SSLv2 ClientHello.
Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
This commit is contained in:
Mateusz Starzyk
parent
e7e5252813
commit
9e9ca1a738
8 changed files with 2 additions and 314 deletions
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@ -1144,269 +1144,6 @@ static int ssl_ciphersuite_match( mbedtls_ssl_context *ssl, int suite_id,
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return( 0 );
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}
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#if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
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static int ssl_parse_client_hello_v2( mbedtls_ssl_context *ssl )
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{
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int ret, got_common_suite;
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unsigned int i, j;
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size_t n;
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unsigned int ciph_len, sess_len, chal_len;
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unsigned char *buf, *p;
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const int *ciphersuites;
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const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
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MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse client hello v2" ) );
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#if defined(MBEDTLS_SSL_RENEGOTIATION)
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if( ssl->renego_status != MBEDTLS_SSL_INITIAL_HANDSHAKE )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "client hello v2 illegal for renegotiation" ) );
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mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
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MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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#endif /* MBEDTLS_SSL_RENEGOTIATION */
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buf = ssl->in_hdr;
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MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, 5 );
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message type: %d",
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buf[2] ) );
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, message len.: %d",
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( ( buf[0] & 0x7F ) << 8 ) | buf[1] ) );
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello v2, max. version: [%d:%d]",
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buf[3], buf[4] ) );
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/*
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* SSLv2 Client Hello
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*
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* Record layer:
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* 0 . 1 message length
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*
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* SSL layer:
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* 2 . 2 message type
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* 3 . 4 protocol version
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*/
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if( buf[2] != MBEDTLS_SSL_HS_CLIENT_HELLO ||
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buf[3] != MBEDTLS_SSL_MAJOR_VERSION_3 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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n = ( ( buf[0] << 8 ) | buf[1] ) & 0x7FFF;
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if( n < 17 || n > 512 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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ssl->major_ver = MBEDTLS_SSL_MAJOR_VERSION_3;
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ssl->minor_ver = ( buf[4] <= ssl->conf->max_minor_ver )
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? buf[4] : ssl->conf->max_minor_ver;
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if( ssl->minor_ver < ssl->conf->min_minor_ver )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "client only supports ssl smaller than minimum"
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" [%d:%d] < [%d:%d]",
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ssl->major_ver, ssl->minor_ver,
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ssl->conf->min_major_ver, ssl->conf->min_minor_ver ) );
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mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
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MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION );
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return( MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION );
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}
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ssl->handshake->max_major_ver = buf[3];
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ssl->handshake->max_minor_ver = buf[4];
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if( ( ret = mbedtls_ssl_fetch_input( ssl, 2 + n ) ) != 0 )
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{
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MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret );
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return( ret );
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}
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ssl->handshake->update_checksum( ssl, buf + 2, n );
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buf = ssl->in_msg;
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n = ssl->in_left - 5;
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/*
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* 0 . 1 ciphersuitelist length
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* 2 . 3 session id length
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* 4 . 5 challenge length
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* 6 . .. ciphersuitelist
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* .. . .. session id
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* .. . .. challenge
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*/
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MBEDTLS_SSL_DEBUG_BUF( 4, "record contents", buf, n );
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ciph_len = ( buf[0] << 8 ) | buf[1];
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sess_len = ( buf[2] << 8 ) | buf[3];
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chal_len = ( buf[4] << 8 ) | buf[5];
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "ciph_len: %d, sess_len: %d, chal_len: %d",
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ciph_len, sess_len, chal_len ) );
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/*
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* Make sure each parameter length is valid
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*/
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if( ciph_len < 3 || ( ciph_len % 3 ) != 0 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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if( sess_len > 32 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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if( chal_len < 8 || chal_len > 32 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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if( n != 6 + ciph_len + sess_len + chal_len )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, ciphersuitelist",
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buf + 6, ciph_len );
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MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, session id",
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buf + 6 + ciph_len, sess_len );
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MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, challenge",
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buf + 6 + ciph_len + sess_len, chal_len );
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p = buf + 6 + ciph_len;
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ssl->session_negotiate->id_len = sess_len;
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memset( ssl->session_negotiate->id, 0,
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sizeof( ssl->session_negotiate->id ) );
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memcpy( ssl->session_negotiate->id, p, ssl->session_negotiate->id_len );
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p += sess_len;
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memset( ssl->handshake->randbytes, 0, 64 );
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memcpy( ssl->handshake->randbytes + 32 - chal_len, p, chal_len );
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/*
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* Check for TLS_EMPTY_RENEGOTIATION_INFO_SCSV
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*/
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for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
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{
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if( p[0] == 0 && p[1] == 0 && p[2] == MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO )
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{
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
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#if defined(MBEDTLS_SSL_RENEGOTIATION)
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if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
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"during renegotiation" ) );
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mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
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MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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#endif /* MBEDTLS_SSL_RENEGOTIATION */
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ssl->secure_renegotiation = MBEDTLS_SSL_SECURE_RENEGOTIATION;
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break;
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}
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}
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#if defined(MBEDTLS_SSL_FALLBACK_SCSV)
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for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
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{
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if( p[0] == 0 &&
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p[1] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE >> 8 ) & 0xff ) &&
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p[2] == (unsigned char)( ( MBEDTLS_SSL_FALLBACK_SCSV_VALUE ) & 0xff ) )
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{
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) );
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if( ssl->minor_ver < ssl->conf->max_minor_ver )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
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mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
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MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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break;
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}
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}
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#endif /* MBEDTLS_SSL_FALLBACK_SCSV */
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got_common_suite = 0;
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ciphersuites = ssl->conf->ciphersuite_list[ssl->minor_ver];
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ciphersuite_info = NULL;
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#if defined(MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
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for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
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for( i = 0; ciphersuites[i] != 0; i++ )
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#else
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for( i = 0; ciphersuites[i] != 0; i++ )
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for( j = 0, p = buf + 6; j < ciph_len; j += 3, p += 3 )
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#endif
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{
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if( p[0] != 0 ||
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p[1] != ( ( ciphersuites[i] >> 8 ) & 0xFF ) ||
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p[2] != ( ( ciphersuites[i] ) & 0xFF ) )
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continue;
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got_common_suite = 1;
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if( ( ret = ssl_ciphersuite_match( ssl, ciphersuites[i],
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&ciphersuite_info ) ) != 0 )
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return( ret );
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if( ciphersuite_info != NULL )
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goto have_ciphersuite_v2;
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}
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if( got_common_suite )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "got ciphersuites in common, "
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"but none of them usable" ) );
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return( MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE );
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}
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else
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no ciphersuites in common" ) );
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return( MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN );
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}
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have_ciphersuite_v2:
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MBEDTLS_SSL_DEBUG_MSG( 2, ( "selected ciphersuite: %s", ciphersuite_info->name ) );
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ssl->session_negotiate->ciphersuite = ciphersuites[i];
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ssl->handshake->ciphersuite_info = ciphersuite_info;
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/*
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* SSLv2 Client Hello relevant renegotiation security checks
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*/
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if( ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION &&
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ssl->conf->allow_legacy_renegotiation == MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "legacy renegotiation, breaking off handshake" ) );
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mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
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MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
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return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
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}
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ssl->in_left = 0;
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ssl->state++;
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MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse client hello v2" ) );
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return( 0 );
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}
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#endif /* MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO */
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/* This function doesn't alert on errors that happen early during
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ClientHello parsing because they might indicate that the client is
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not talking SSL/TLS at all and would not understand our alert. */
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@ -1461,14 +1198,6 @@ read_record_header:
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buf = ssl->in_hdr;
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#if defined(MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO)
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#if defined(MBEDTLS_SSL_PROTO_DTLS)
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if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_STREAM )
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#endif
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if( ( buf[0] & 0x80 ) != 0 )
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return( ssl_parse_client_hello_v2( ssl ) );
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#endif
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MBEDTLS_SSL_DEBUG_BUF( 4, "record header", buf, mbedtls_ssl_in_hdr_len( ssl ) );
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/*
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