/src/gnutls/lib/ext/ext_master_secret.c

Source
/*
 * Copyright (C) 2014-2017 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/>
 *
 */

/* This file contains the code for the RFC7627 (ext master secret) TLS extension.
 */

#include "gnutls_int.h"
#include "errors.h"
#include "num.h"
#include "hello_ext.h"
#include "ext/ext_master_secret.h"

static int _gnutls_ext_master_secret_recv_params(gnutls_session_t session,
             const uint8_t *data,
             size_t data_size);
static int _gnutls_ext_master_secret_send_params(gnutls_session_t session,
             gnutls_buffer_st *extdata);

const hello_ext_entry_st ext_mod_ext_master_secret = {
  .name = "Extended Master Secret",
  .tls_id = 23,
  .gid = GNUTLS_EXTENSION_EXT_MASTER_SECRET,
  .client_parse_point = GNUTLS_EXT_MANDATORY,
  .server_parse_point = GNUTLS_EXT_MANDATORY,
  .validity = GNUTLS_EXT_FLAG_TLS | GNUTLS_EXT_FLAG_DTLS |
        GNUTLS_EXT_FLAG_CLIENT_HELLO |
        GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO,
  .recv_func = _gnutls_ext_master_secret_recv_params,
  .send_func = _gnutls_ext_master_secret_send_params,
  .pack_func = NULL,
  .unpack_func = NULL,
  .deinit_func = NULL,
  .cannot_be_overriden = 1
};

#ifdef ENABLE_SSL3
static inline unsigned have_only_ssl3_enabled(gnutls_session_t session)
{
  if (session->internals.priorities->protocol.num_priorities == 1 &&
      session->internals.priorities->protocol.priorities[0] ==
        GNUTLS_SSL3)
    return 1;
  return 0;
}
#endif

/*
 * In case of a server: if an EXT_MASTER_SECRET extension type is received then it
 * sets a flag into the session security parameters.
 *
 */
static int _gnutls_ext_master_secret_recv_params(gnutls_session_t session,
             const uint8_t *data,
             size_t data_size)
{
  if ((session->internals.flags & GNUTLS_NO_DEFAULT_EXTENSIONS) ||
      session->internals.priorities->no_extensions ||
      session->internals.no_ext_master_secret != 0) {
    return 0;
  }

  if (data_size != 0) {
    return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
  }
#ifdef ENABLE_SSL3
  if (session->security_parameters.entity == GNUTLS_CLIENT) {
    const version_entry_st *ver = get_version(session);

    if (unlikely(ver == NULL))
      return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

    if (ver->id != GNUTLS_SSL3)
      session->security_parameters.ext_master_secret = 1;
    /* do not enable ext master secret if SSL 3.0 is the only protocol supported by server */
  } else if (!have_only_ssl3_enabled(session))
#endif
    session->security_parameters.ext_master_secret = 1;

  return 0;
}

/* returns data_size or a negative number on failure
 */
static int _gnutls_ext_master_secret_send_params(gnutls_session_t session,
             gnutls_buffer_st *extdata)
{
  if ((session->internals.flags & GNUTLS_NO_DEFAULT_EXTENSIONS) ||
      session->internals.priorities->no_extensions != 0 ||
      session->internals.no_ext_master_secret != 0) {
    session->security_parameters.ext_master_secret = 0;
    return 0;
  }

  /* this function sends the client extension data */
#ifdef ENABLE_SSL3
  if (session->security_parameters.entity == GNUTLS_CLIENT) {
    if (have_only_ssl3_enabled(session))
      return 0; /* this extension isn't available for SSL 3.0 */

    return GNUTLS_E_INT_RET_0;
  } else { /* server side */
    const version_entry_st *ver = get_version(session);
    if (unlikely(ver == NULL))
      return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);

    if (ver->id != GNUTLS_SSL3 &&
        session->security_parameters.ext_master_secret != 0)
      return GNUTLS_E_INT_RET_0;
  }

  return 0;
#else
  if (session->security_parameters.entity == GNUTLS_CLIENT ||
      session->security_parameters.ext_master_secret != 0)
    return GNUTLS_E_INT_RET_0;
  return 0;
#endif
}

/**
 * gnutls_session_ext_master_secret_status:
 * @session: is a #gnutls_session_t type.
 *
 * Get the status of the extended master secret extension negotiation.
 * This is in accordance to RFC7627. That information is also
 * available to the more generic gnutls_session_get_flags().
 *
 * Returns: Non-zero if the negotiation was successful or zero otherwise.
 **/
unsigned gnutls_session_ext_master_secret_status(gnutls_session_t session)
{
  return session->security_parameters.ext_master_secret;
}

Line	Count	Source
1		/*
2		* Copyright (C) 2014-2017 Red Hat, Inc.
3		*
4		* Author: Nikos Mavrogiannopoulos
5		*
6		* This file is part of GnuTLS.
7		*
8		* The GnuTLS is free software; you can redistribute it and/or
9		* modify it under the terms of the GNU Lesser General Public License
10		* as published by the Free Software Foundation; either version 2.1 of
11		* the License, or (at your option) any later version.
12		*
13		* This library is distributed in the hope that it will be useful, but
14		* WITHOUT ANY WARRANTY; without even the implied warranty of
15		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16		* Lesser General Public License for more details.
17		*
18		* You should have received a copy of the GNU Lesser General Public License
19		* along with this program. If not, see <https://www.gnu.org/licenses/>
20		*
21		*/
22
23		/* This file contains the code for the RFC7627 (ext master secret) TLS extension.
24		*/
25
26		#include "gnutls_int.h"
27		#include "errors.h"
28		#include "num.h"
29		#include "hello_ext.h"
30		#include "ext/ext_master_secret.h"
31
32		static int _gnutls_ext_master_secret_recv_params(gnutls_session_t session,
33		const uint8_t *data,
34		size_t data_size);
35		static int _gnutls_ext_master_secret_send_params(gnutls_session_t session,
36		gnutls_buffer_st *extdata);
37
38		const hello_ext_entry_st ext_mod_ext_master_secret = {
39		.name = "Extended Master Secret",
40		.tls_id = 23,
41		.gid = GNUTLS_EXTENSION_EXT_MASTER_SECRET,
42		.client_parse_point = GNUTLS_EXT_MANDATORY,
43		.server_parse_point = GNUTLS_EXT_MANDATORY,
44		.validity = GNUTLS_EXT_FLAG_TLS \| GNUTLS_EXT_FLAG_DTLS \|
45		GNUTLS_EXT_FLAG_CLIENT_HELLO \|
46		GNUTLS_EXT_FLAG_TLS12_SERVER_HELLO,
47		.recv_func = _gnutls_ext_master_secret_recv_params,
48		.send_func = _gnutls_ext_master_secret_send_params,
49		.pack_func = NULL,
50		.unpack_func = NULL,
51		.deinit_func = NULL,
52		.cannot_be_overriden = 1
53		};
54
55		#ifdef ENABLE_SSL3
56		static inline unsigned have_only_ssl3_enabled(gnutls_session_t session)
57		{
58		if (session->internals.priorities->protocol.num_priorities == 1 &&
59		session->internals.priorities->protocol.priorities[0] ==
60		GNUTLS_SSL3)
61		return 1;
62		return 0;
63		}
64		#endif
65
66		/*
67		* In case of a server: if an EXT_MASTER_SECRET extension type is received then it
68		* sets a flag into the session security parameters.
69		*
70		*/
71		static int _gnutls_ext_master_secret_recv_params(gnutls_session_t session,
72		const uint8_t *data,
73		size_t data_size)
74	0	{
75	0	if ((session->internals.flags & GNUTLS_NO_DEFAULT_EXTENSIONS) \|\|
76	0	session->internals.priorities->no_extensions \|\|
77	0	session->internals.no_ext_master_secret != 0) {
78	0	return 0;
79	0	}
80
81	0	if (data_size != 0) {
82	0	return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
83	0	}
84		#ifdef ENABLE_SSL3
85		if (session->security_parameters.entity == GNUTLS_CLIENT) {
86		const version_entry_st *ver = get_version(session);
87
88		if (unlikely(ver == NULL))
89		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
90
91		if (ver->id != GNUTLS_SSL3)
92		session->security_parameters.ext_master_secret = 1;
93		/* do not enable ext master secret if SSL 3.0 is the only protocol supported by server */
94		} else if (!have_only_ssl3_enabled(session))
95		#endif
96	0	session->security_parameters.ext_master_secret = 1;
97
98	0	return 0;
99	0	}
100
101		/* returns data_size or a negative number on failure
102		*/
103		static int _gnutls_ext_master_secret_send_params(gnutls_session_t session,
104		gnutls_buffer_st *extdata)
105	0	{
106	0	if ((session->internals.flags & GNUTLS_NO_DEFAULT_EXTENSIONS) \|\|
107	0	session->internals.priorities->no_extensions != 0 \|\|
108	0	session->internals.no_ext_master_secret != 0) {
109	0	session->security_parameters.ext_master_secret = 0;
110	0	return 0;
111	0	}
112
113		/* this function sends the client extension data */
114		#ifdef ENABLE_SSL3
115		if (session->security_parameters.entity == GNUTLS_CLIENT) {
116		if (have_only_ssl3_enabled(session))
117		return 0; /* this extension isn't available for SSL 3.0 */
118
119		return GNUTLS_E_INT_RET_0;
120		} else { /* server side */
121		const version_entry_st *ver = get_version(session);
122		if (unlikely(ver == NULL))
123		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
124
125		if (ver->id != GNUTLS_SSL3 &&
126		session->security_parameters.ext_master_secret != 0)
127		return GNUTLS_E_INT_RET_0;
128		}
129
130		return 0;
131		#else
132	0	if (session->security_parameters.entity == GNUTLS_CLIENT \|\|
133	0	session->security_parameters.ext_master_secret != 0)
134	0	return GNUTLS_E_INT_RET_0;
135	0	return 0;
136	0	#endif
137	0	}
138
139		/**
140		* gnutls_session_ext_master_secret_status:
141		* @session: is a #gnutls_session_t type.
142		*
143		* Get the status of the extended master secret extension negotiation.
144		* This is in accordance to RFC7627. That information is also
145		* available to the more generic gnutls_session_get_flags().
146		*
147		* Returns: Non-zero if the negotiation was successful or zero otherwise.
148		**/
149		unsigned gnutls_session_ext_master_secret_status(gnutls_session_t session)
150	0	{
151	0	return session->security_parameters.ext_master_secret;
152	0	}

Coverage Report

Created: 2026-08-14 06:46