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Implement FALLBACK_SCSV server-side

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This commit is contained in:
Manuel Pégourié-Gonnard
2014-10-20 14:05:28 +02:00
parent 1cbd39dbeb
commit 01b2699198
3 changed files with 87 additions and 0 deletions
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47
library/ssl_srv.c
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@ -1052,6 +1052,30 @@ static int ssl_parse_client_hello_v2( ssl_context *ssl )
}
}
#if defined(POLARSSL_SSL_FALLBACK_SCSV)
for( i = 0, p = buf + 6; i < ciph_len; i += 3, p += 3 )
{
if( p[0] == 0 &&
p[1] == (unsigned char)( ( SSL_FALLBACK_SCSV >> 8 ) & 0xff ) &&
p[2] == (unsigned char)( ( SSL_FALLBACK_SCSV ) & 0xff ) )
{
SSL_DEBUG_MSG( 3, ( "received FALLBACK_SCSV" ) );
if( ssl->minor_ver < ssl->max_minor_ver )
{
SSL_DEBUG_MSG( 1, ( "inapropriate fallback" ) );
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
break;
}
}
#endif /* POLARSSL_SSL_FALLBACK_SCSV */
ciphersuites = ssl->ciphersuite_list[ssl->minor_ver];
ciphersuite_info = NULL;
#if defined(POLARSSL_SSL_SRV_RESPECT_CLIENT_PREFERENCE)
@ -1365,6 +1389,29 @@ static int ssl_parse_client_hello( ssl_context *ssl )
}
}
#if defined(POLARSSL_SSL_FALLBACK_SCSV)
for( i = 0, p = buf + 41 + sess_len; i < ciph_len; i += 2, p += 2 )
{
if( p[0] == (unsigned char)( ( SSL_FALLBACK_SCSV >> 8 ) & 0xff ) &&
p[1] == (unsigned char)( ( SSL_FALLBACK_SCSV ) & 0xff ) )
{
SSL_DEBUG_MSG( 0, ( "received FALLBACK_SCSV" ) );
if( ssl->minor_ver < ssl->max_minor_ver )
{
SSL_DEBUG_MSG( 0, ( "inapropriate fallback" ) );
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_INAPROPRIATE_FALLBACK );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
break;
}
}
#endif /* POLARSSL_SSL_FALLBACK_SCSV */
ext = buf + 44 + sess_len + ciph_len + comp_len;
while( ext_len )