Commit 89e35798 authored by Manuel Pégourié-Gonnard's avatar Manuel Pégourié-Gonnard
Browse files

Implement ALPN server-side

parent 0b874dc5
......@@ -320,6 +320,7 @@
#define SSL_ALERT_MSG_UNSUPPORTED_EXT 110 /* 0x6E */
#define SSL_ALERT_MSG_UNRECOGNIZED_NAME 112 /* 0x70 */
#define SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY 115 /* 0x73 */
#define SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL 120 /* 0x78 */
#define SSL_HS_HELLO_REQUEST 0
#define SSL_HS_CLIENT_HELLO 1
......
......@@ -683,6 +683,69 @@ static int ssl_parse_session_ticket_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_SESSION_TICKETS */
#if defined(POLARSSL_SSL_ALPN)
static int ssl_parse_alpn_ext( ssl_context *ssl,
unsigned char *buf, size_t len )
{
size_t list_len, cur_len;
const unsigned char *theirs, *start, *end;
const char **ours;
/* If ALPN not configured, just ignore the extension */
if( ssl->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 )
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
list_len = ( buf[0] << 8 ) | buf[1];
if( list_len != len - 2 )
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
/*
* Use our order of preference
*/
start = buf + 2;
end = buf + len;
for( ours = ssl->alpn_list; *ours != NULL; ours++ )
{
for( theirs = start; theirs != end; theirs += cur_len )
{
/* If the list is well formed, we should get equality first */
if( theirs > end )
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
cur_len = *theirs++;
/* Empty strings MUST NOT be included */
if( cur_len == 0 )
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
if( cur_len == strlen( *ours ) &&
memcmp( theirs, *ours, cur_len ) == 0 )
{
ssl->alpn_chosen = *ours;
return( 0 );
}
}
}
/* If we get there, no match was found */
ssl_send_alert_message( ssl, SSL_ALERT_LEVEL_FATAL,
SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
#endif /* POLARSSL_SSL_ALPN */
/*
* Auxiliary functions for ServerHello parsing and related actions
*/
......@@ -1385,6 +1448,16 @@ static int ssl_parse_client_hello( ssl_context *ssl )
break;
#endif /* POLARSSL_SSL_SESSION_TICKETS */
#if defined(POLARSSL_SSL_ALPN)
case TLS_EXT_ALPN:
SSL_DEBUG_MSG( 3, ( "found ALPN extension" ) );
ret = ssl_parse_alpn_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_SESSION_TICKETS */
default:
SSL_DEBUG_MSG( 3, ( "unknown extension found: %d (ignoring)",
ext_id ) );
......@@ -1625,6 +1698,42 @@ static void ssl_write_supported_point_formats_ext( ssl_context *ssl,
}
#endif /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */
#if defined(POLARSSL_SSL_ALPN )
static void ssl_write_alpn_ext( ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
if( ssl->alpn_chosen == NULL )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, 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)( ( TLS_EXT_ALPN >> 8 ) & 0xFF );
buf[1] = (unsigned char)( ( 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 /* POLARSSL_ECDH_C || POLARSSL_ECDSA_C */
static int ssl_write_server_hello( ssl_context *ssl )
{
#if defined(POLARSSL_HAVE_TIME)
......@@ -1791,6 +1900,11 @@ static int ssl_write_server_hello( ssl_context *ssl )
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_ALPN)
ssl_write_alpn_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
SSL_DEBUG_MSG( 3, ( "server hello, total extension length: %d", ext_len ) );
*p++ = (unsigned char)( ( ext_len >> 8 ) & 0xFF );
......
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