/src/gnutls/lib/hello_ext.h

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/*
 * Copyright (C) 2000-2012 Free Software Foundation, Inc.
 * Copyright (C) 2015-2018 Red Hat, Inc.
 *
 * Author: Nikos Mavrogiannopoulos
 *
 * This file is part of GnuTLS.
 *
 * The GnuTLS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>
 *
 */

#ifndef GNUTLS_LIB_HELLO_EXT_H
#define GNUTLS_LIB_HELLO_EXT_H

#include "gnutls_int.h"
#include <gnutls/gnutls.h>
#include "str.h"

/* Functions for hello extension parsing.
 */
int _gnutls_parse_hello_extensions(gnutls_session_t session,
           gnutls_ext_flags_t msg,
           gnutls_ext_parse_type_t parse_type,
           const uint8_t *data, int data_size);
int _gnutls_gen_hello_extensions(gnutls_session_t session,
         gnutls_buffer_st *extdata,
         gnutls_ext_flags_t msg,
         gnutls_ext_parse_type_t);
int _gnutls_hello_ext_init(void);
void _gnutls_hello_ext_deinit(void);

void _gnutls_hello_ext_priv_deinit(gnutls_session_t session);

/* functions to be used by extensions internally
 */
void _gnutls_hello_ext_unset_priv(gnutls_session_t session, extensions_t ext);
void _gnutls_hello_ext_set_priv(gnutls_session_t session, extensions_t ext,
        gnutls_ext_priv_data_t);
int _gnutls_hello_ext_get_priv(gnutls_session_t session, extensions_t ext,
             gnutls_ext_priv_data_t *);
int _gnutls_hello_ext_get_resumed_priv(gnutls_session_t session,
               extensions_t ext,
               gnutls_ext_priv_data_t *data);

#define GNUTLS_EXT_FLAG_MSG_MASK                                             \
  (GNUTLS_EXT_FLAG_CLIENT_HELLO | GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO | \
   GNUTLS_EXT_FLAG_TLS13_SERVER_HELLO | GNUTLS_EXT_FLAG_EE |           \
   GNUTLS_EXT_FLAG_HRR)

/* these flags can only be set in the extensions, but cannot be requested;
 * they are handled internally by the hello parsing/generating functions. */
#define GNUTLS_EXT_FLAG_SET_ONLY_FLAGS_MASK \
  ~(GNUTLS_EXT_FLAG_DTLS | GNUTLS_EXT_FLAG_TLS)

/* obtain the message this extension was received at */
inline static gnutls_ext_flags_t _gnutls_ext_get_msg(gnutls_session_t session)
{
  return session->internals.ext_msg & GNUTLS_EXT_FLAG_MSG_MASK;
}

inline static void _gnutls_ext_set_msg(gnutls_session_t session,
               gnutls_ext_flags_t msg)
{
  session->internals.ext_msg = msg;
}

inline static void _gnutls_ext_set_extensions_offset(gnutls_session_t session,
                 int offset)
{
  session->internals.extensions_offset = offset;
}

inline static int _gnutls_ext_get_extensions_offset(gnutls_session_t session)
{
  return session->internals.extensions_offset;
}

int _gnutls_ext_set_full_client_hello(gnutls_session_t session,
              handshake_buffer_st *recv_buf);
unsigned _gnutls_ext_get_full_client_hello(gnutls_session_t session,
             gnutls_datum_t *datum);

/* for session packing */
int _gnutls_hello_ext_pack(gnutls_session_t session, gnutls_buffer_st *packed);
int _gnutls_hello_ext_unpack(gnutls_session_t session,
           gnutls_buffer_st *packed);

inline static const char *ext_msg_validity_to_str(gnutls_ext_flags_t msg)
{
  msg &= GNUTLS_EXT_FLAG_MSG_MASK;

  switch (msg) {
  case GNUTLS_EXT_FLAG_CLIENT_HELLO:
    return "client hello";
  case GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO:
    return "TLS 1.2 server hello";
  case GNUTLS_EXT_FLAG_TLS13_SERVER_HELLO:
    return "TLS 1.3 server hello";
  case GNUTLS_EXT_FLAG_EE:
    return "encrypted extensions";
  case GNUTLS_EXT_FLAG_HRR:
    return "hello retry request";
  default:
    return "(unknown)";
  }
}

typedef struct hello_ext_entry_st {
  const char *name; /* const overridden when free_struct is set */
  unsigned free_struct;

  uint16_t tls_id;
  unsigned gid; /* gnutls internal ID */

  gnutls_ext_parse_type_t client_parse_point;
  gnutls_ext_parse_type_t server_parse_point;
  unsigned validity; /* multiple items of gnutls_ext_flags_t */

  /* this function must return 0 when Not Applicable
   * size of extension data if ok
   * < 0 on other error.
   */
  gnutls_ext_recv_func recv_func;

  /* this function must return 0 when Not Applicable
   * size of extension data if ok
   * GNUTLS_E_INT_RET_0 if extension data size is zero
   * < 0 on other error.
   */
  gnutls_ext_send_func send_func;

  gnutls_ext_deinit_data_func
    deinit_func; /* this will be called to deinitialize
               * internal data
               */
  gnutls_ext_pack_func
    pack_func; /* packs internal data to machine independent format */
  gnutls_ext_unpack_func unpack_func; /* unpacks internal data */

  /* non-zero if that extension cannot be overridden by the applications.
   * That should be set to extensions which allocate data early, e.g., on
   * gnutls_init(), or modify the TLS protocol in a way that the application
   * cannot control. */
  unsigned cannot_be_overriden;
} hello_ext_entry_st;

/* Checks if the extension @id provided has been requested
 * by us (in client side).In server side it checks whether this
 * extension was advertised by the client.
 *
 * It returns non-zero for true, otherwise zero.
 */
inline static unsigned _gnutls_hello_ext_is_present(gnutls_session_t session,
                extensions_t id)
{
  if (session->internals.used_exts & ((ext_track_t)1 << id))
    return 1;

  return 0;
}

/* Adds the extension we want to send in the extensions list.
 * This list is used in client side to check whether the (later) received
 * extensions are the ones we requested.
 *
 * In server side, this list is used to ensure we don't send
 * extensions that we didn't receive a corresponding value.
 *
 * Returns zero if failed, non-zero on success.
 */
inline static unsigned _gnutls_hello_ext_save(gnutls_session_t session,
                extensions_t id,
                unsigned check_dup)
{
  if (check_dup && _gnutls_hello_ext_is_present(session, id)) {
    return 0;
  }

  session->internals.used_exts |= ((ext_track_t)1 << id);

  return 1;
}

inline static void _gnutls_hello_ext_save_sr(gnutls_session_t session)
{
  _gnutls_hello_ext_save(session, GNUTLS_EXTENSION_SAFE_RENEGOTIATION, 1);
}

#endif /* GNUTLS_LIB_HELLO_EXT_H */

Coverage Report

Created: 2025-03-06 06:58

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright (C) 2000-2012 Free Software Foundation, Inc.
3		* Copyright (C) 2015-2018 Red Hat, Inc.
4		*
5		* Author: Nikos Mavrogiannopoulos
6		*
7		* This file is part of GnuTLS.
8		*
9		* The GnuTLS is free software; you can redistribute it and/or
10		* modify it under the terms of the GNU Lesser General Public License
11		* as published by the Free Software Foundation; either version 2.1 of
12		* the License, or (at your option) any later version.
13		*
14		* This library is distributed in the hope that it will be useful, but
15		* WITHOUT ANY WARRANTY; without even the implied warranty of
16		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17		* Lesser General Public License for more details.
18		*
19		* You should have received a copy of the GNU Lesser General Public License
20		* along with this program. If not, see <https://www.gnu.org/licenses/>
21		*
22		*/
23
24		#ifndef GNUTLS_LIB_HELLO_EXT_H
25		#define GNUTLS_LIB_HELLO_EXT_H
26
27		#include "gnutls_int.h"
28		#include <gnutls/gnutls.h>
29		#include "str.h"
30
31		/* Functions for hello extension parsing.
32		*/
33		int _gnutls_parse_hello_extensions(gnutls_session_t session,
34		gnutls_ext_flags_t msg,
35		gnutls_ext_parse_type_t parse_type,
36		const uint8_t *data, int data_size);
37		int _gnutls_gen_hello_extensions(gnutls_session_t session,
38		gnutls_buffer_st *extdata,
39		gnutls_ext_flags_t msg,