Implement initial negotiation of EtM

Not implemented yet:
- actually using EtM
- conditions on renegotiation
This commit is contained in:
Manuel Pégourié-Gonnard 2014-10-27 13:57:03 +01:00
parent b3c6a97b31
commit 699cafaea2
9 changed files with 308 additions and 2 deletions

View file

@ -359,6 +359,32 @@ static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static void ssl_write_encrypt_then_mac_ext( ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
unsigned char *p = buf;
if( ssl->encrypt_then_mac == SSL_ETM_DISABLED ||
ssl->max_minor_ver == SSL_MINOR_VERSION_0 )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "client hello, adding encrypt_then_mac "
"extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static void ssl_write_extended_ms_ext( ssl_context *ssl,
unsigned char *buf, size_t *olen )
@ -688,6 +714,11 @@ static int ssl_write_client_hello( ssl_context *ssl )
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
@ -811,6 +842,26 @@ static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static int ssl_parse_encrypt_then_mac_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( ssl->encrypt_then_mac == SSL_ETM_DISABLED ||
ssl->minor_ver == SSL_MINOR_VERSION_0 ||
len != 0 )
{
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
((void) buf);
ssl->session_negotiate->encrypt_then_mac = SSL_ETM_ENABLED;
return( 0 );
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static int ssl_parse_extended_ms_ext( ssl_context *ssl,
const unsigned char *buf,
@ -1203,6 +1254,19 @@ static int ssl_parse_server_hello( ssl_context *ssl )
break;
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
case TLS_EXT_ENCRYPT_THEN_MAC:
SSL_DEBUG_MSG( 3, ( "found encrypt_then_mac extension" ) );
if( ( ret = ssl_parse_encrypt_then_mac_ext( ssl,
ext + 4, ext_size ) ) != 0 )
{
return( ret );
}
break;
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
case TLS_EXT_EXTENDED_MASTER_SECRET:
SSL_DEBUG_MSG( 3, ( "found extended_master_secret extension" ) );

View file

@ -635,6 +635,29 @@ static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static int ssl_parse_encrypt_then_mac_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( len != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
((void) buf);
if( ssl->encrypt_then_mac == SSL_ETM_ENABLED &&
ssl->minor_ver != SSL_MINOR_VERSION_0 )
{
ssl->session_negotiate->encrypt_then_mac = SSL_ETM_ENABLED;
}
return( 0 );
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static int ssl_parse_extended_ms_ext( ssl_context *ssl,
const unsigned char *buf,
@ -1523,6 +1546,16 @@ static int ssl_parse_client_hello( ssl_context *ssl )
break;
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
case TLS_EXT_ENCRYPT_THEN_MAC:
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 /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
case TLS_EXT_EXTENDED_MASTER_SECRET:
SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) );
@ -1682,6 +1715,32 @@ static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static void ssl_write_encrypt_then_mac_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
if( ssl->session_negotiate->encrypt_then_mac == SSL_EXTENDED_MS_DISABLED ||
ssl->minor_ver == SSL_MINOR_VERSION_0 )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static void ssl_write_extended_ms_ext( ssl_context *ssl,
unsigned char *buf,
@ -2012,6 +2071,11 @@ static int ssl_write_server_hello( ssl_context *ssl )
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;

View file

@ -1071,6 +1071,15 @@ static int ssl_encrypt_buf( ssl_context *ssl )
SSL_DEBUG_MSG( 2, ( "=> encrypt buf" ) );
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
if( ssl->session_out != NULL &&
ssl->session_out->encrypt_then_mac == SSL_ETM_ENABLED )
{
// WIP
SSL_DEBUG_MSG( 3, ( "using encrypt then mac" ) );
}
#endif
/*
* Add MAC before encrypt, except for AEAD modes
*/
@ -3474,6 +3483,10 @@ int ssl_init( ssl_context *ssl )
memset( ssl-> in_ctr, 0, SSL_BUFFER_LEN );
memset( ssl->out_ctr, 0, SSL_BUFFER_LEN );
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
ssl->encrypt_then_mac = SSL_ETM_ENABLED;
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
ssl->extended_ms = SSL_EXTENDED_MS_ENABLED;
#endif
@ -4025,6 +4038,13 @@ void ssl_set_fallback( ssl_context *ssl, char fallback )
}
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
void ssl_set_encrypt_then_mac( ssl_context *ssl, char etm )
{
ssl->encrypt_then_mac = etm;
}
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
void ssl_set_extended_master_secret( ssl_context *ssl, char ems )
{