Blame lib/hello_ext.h

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/*
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 * Copyright (C) 2000-2012 Free Software Foundation, Inc.
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 * Copyright (C) 2015-2018 Red Hat, Inc.
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 *
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 * Author: Nikos Mavrogiannopoulos
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 *
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 * This file is part of GnuTLS.
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 *
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 * The GnuTLS is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public License
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 * as published by the Free Software Foundation; either version 2.1 of
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 * the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful, but
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 * WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public License
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 * along with this program.  If not, see <https://www.gnu.org/licenses/>
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 *
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 */
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#ifndef GNUTLS_LIB_HELLO_EXT_H
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#define GNUTLS_LIB_HELLO_EXT_H
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#include "gnutls_int.h"
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#include <gnutls/gnutls.h>
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#include "str.h"
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/* Functions for hello extension parsing.
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 */
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int _gnutls_parse_hello_extensions(gnutls_session_t session,
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				   gnutls_ext_flags_t msg,
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				   gnutls_ext_parse_type_t parse_type,
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				   const uint8_t * data, int data_size);
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int _gnutls_gen_hello_extensions(gnutls_session_t session,
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				 gnutls_buffer_st * extdata,
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				 gnutls_ext_flags_t msg,
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				 gnutls_ext_parse_type_t);
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int _gnutls_hello_ext_init(void);
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void _gnutls_hello_ext_deinit(void);
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void _gnutls_hello_ext_priv_deinit(gnutls_session_t session);
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/* functions to be used by extensions internally
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 */
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void _gnutls_hello_ext_unset_priv(gnutls_session_t session,
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				    extensions_t ext);
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void _gnutls_hello_ext_set_priv(gnutls_session_t session, extensions_t ext,
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				  gnutls_ext_priv_data_t);
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int _gnutls_hello_ext_get_priv(gnutls_session_t session, extensions_t ext,
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				 gnutls_ext_priv_data_t *);
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int _gnutls_hello_ext_get_resumed_priv(gnutls_session_t session,
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					 extensions_t ext,
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					 gnutls_ext_priv_data_t * data);
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#define GNUTLS_EXT_FLAG_MSG_MASK (GNUTLS_EXT_FLAG_CLIENT_HELLO | GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO| \
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		 GNUTLS_EXT_FLAG_TLS13_SERVER_HELLO | GNUTLS_EXT_FLAG_EE | GNUTLS_EXT_FLAG_HRR)
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/* these flags can only be set in the extensions, but cannot be requested;
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 * they are handled internally by the hello parsing/generating functions. */
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#define GNUTLS_EXT_FLAG_SET_ONLY_FLAGS_MASK ~(GNUTLS_EXT_FLAG_DTLS | GNUTLS_EXT_FLAG_TLS)
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/* obtain the message this extension was received at */
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inline static gnutls_ext_flags_t _gnutls_ext_get_msg(gnutls_session_t session)
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{
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	return session->internals.ext_msg & GNUTLS_EXT_FLAG_MSG_MASK;
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}
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inline static void _gnutls_ext_set_msg(gnutls_session_t session, gnutls_ext_flags_t msg)
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{
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	session->internals.ext_msg = msg;
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}
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inline static void _gnutls_ext_set_extensions_offset(gnutls_session_t session,
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		int offset)
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{
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	session->internals.extensions_offset = offset;
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}
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inline static int _gnutls_ext_get_extensions_offset(gnutls_session_t session)
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{
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	return session->internals.extensions_offset;
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}
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int _gnutls_ext_set_full_client_hello(gnutls_session_t session,
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				      handshake_buffer_st *recv_buf);
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unsigned _gnutls_ext_get_full_client_hello(gnutls_session_t session,
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					   gnutls_datum_t *datum);
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/* for session packing */
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int _gnutls_hello_ext_pack(gnutls_session_t session, gnutls_buffer_st * packed);
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int _gnutls_hello_ext_unpack(gnutls_session_t session,
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		       gnutls_buffer_st * packed);
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inline static const char *ext_msg_validity_to_str(gnutls_ext_flags_t msg)
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{
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	msg &= GNUTLS_EXT_FLAG_MSG_MASK;
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	switch(msg) {
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		case GNUTLS_EXT_FLAG_CLIENT_HELLO:
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			return "client hello";
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		case GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO:
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			return "TLS 1.2 server hello";
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		case GNUTLS_EXT_FLAG_TLS13_SERVER_HELLO:
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			return "TLS 1.3 server hello";
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		case GNUTLS_EXT_FLAG_EE:
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			return "encrypted extensions";
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		case GNUTLS_EXT_FLAG_HRR:
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			return "hello retry request";
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		default:
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			return "(unknown)";
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	}
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}
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typedef struct hello_ext_entry_st {
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	const char *name; /* const overridden when free_struct is set */
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	unsigned free_struct;
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	uint16_t tls_id;
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	unsigned gid; /* gnutls internal ID */
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	gnutls_ext_parse_type_t client_parse_point;
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	gnutls_ext_parse_type_t server_parse_point;
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	unsigned validity; /* multiple items of gnutls_ext_flags_t */
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	/* this function must return 0 when Not Applicable
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	 * size of extension data if ok
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	 * < 0 on other error.
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	 */
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	gnutls_ext_recv_func recv_func;
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	/* this function must return 0 when Not Applicable
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	 * size of extension data if ok
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	 * GNUTLS_E_INT_RET_0 if extension data size is zero
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	 * < 0 on other error.
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	 */
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	gnutls_ext_send_func send_func;
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	gnutls_ext_deinit_data_func deinit_func;	/* this will be called to deinitialize
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							 * internal data
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							 */
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	gnutls_ext_pack_func pack_func;	/* packs internal data to machine independent format */
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	gnutls_ext_unpack_func unpack_func;	/* unpacks internal data */
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	/* non-zero if that extension cannot be overridden by the applications.
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	 * That should be set to extensions which allocate data early, e.g., on
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	 * gnutls_init(), or modify the TLS protocol in a way that the application
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	 * cannot control. */
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	unsigned cannot_be_overriden;
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} hello_ext_entry_st;
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/* Checks if the extension @id provided has been requested
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 * by us (in client side).In server side it checks whether this
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 * extension was advertized by the client.
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 *
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 * It returns non-zero for true, otherwise zero.
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 */
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inline static unsigned
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_gnutls_hello_ext_is_present(gnutls_session_t session, extensions_t id)
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{
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	if (session->internals.used_exts & ((ext_track_t)1 << id))
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		return 1;
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	return 0;
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}
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/* Adds the extension we want to send in the extensions list.
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 * This list is used in client side to check whether the (later) received
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 * extensions are the ones we requested.
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 *
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 * In server side, this list is used to ensure we don't send
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 * extensions that we didn't receive a corresponding value.
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 *
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 * Returns zero if failed, non-zero on success.
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 */
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inline static
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unsigned _gnutls_hello_ext_save(gnutls_session_t session,
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				extensions_t id,
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				unsigned check_dup)
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{
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	if (check_dup && _gnutls_hello_ext_is_present(session, id)) {
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			return 0;
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	}
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	session->internals.used_exts |= ((ext_track_t)1 << id);
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	return 1;
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}
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inline static
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void _gnutls_hello_ext_save_sr(gnutls_session_t session)
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{
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	_gnutls_hello_ext_save(session, GNUTLS_EXTENSION_SAFE_RENEGOTIATION, 1);
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}
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#endif /* GNUTLS_LIB_HELLO_EXT_H */