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/*
* Copyright (C) 2002, 2003, 2004, 2005, 2010 Free Software Foundation,
* 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA
*
*/
/* This file contains the code the Certificate Type TLS extension.
* This extension is currently gnutls specific.
*/
#include "gnutls_int.h"
#include "gnutls_errors.h"
#include "gnutls_num.h"
#include <ext/ecc.h>
#include <gnutls_state.h>
#include <gnutls_num.h>
/* Maps record size to numbers according to the
* extensions draft.
*/
static int _gnutls_supported_ecc_recv_params (gnutls_session_t session,
const opaque * data,
size_t data_size);
static int _gnutls_supported_ecc_send_params (gnutls_session_t session,
gnutls_buffer_st * extdata);
static int _gnutls_supported_ecc_pf_recv_params (gnutls_session_t session,
const opaque * data,
size_t data_size);
static int _gnutls_supported_ecc_pf_send_params (gnutls_session_t session,
gnutls_buffer_st * extdata);
extension_entry_st ext_mod_supported_ecc = {
.name = "SUPPORTED ECC",
.type = GNUTLS_EXTENSION_SUPPORTED_ECC,
.parse_type = GNUTLS_EXT_TLS,
.recv_func = _gnutls_supported_ecc_recv_params,
.send_func = _gnutls_supported_ecc_send_params,
.pack_func = NULL,
.unpack_func = NULL,
.deinit_func = NULL
};
extension_entry_st ext_mod_supported_ecc_pf = {
.name = "SUPPORTED ECC POINT FORMATS",
.type = GNUTLS_EXTENSION_SUPPORTED_ECC_PF,
.parse_type = GNUTLS_EXT_TLS,
.recv_func = _gnutls_supported_ecc_pf_recv_params,
.send_func = _gnutls_supported_ecc_pf_send_params,
.pack_func = NULL,
.unpack_func = NULL,
.deinit_func = NULL
};
/*
* In case of a server: if a SUPPORTED_ECC extension type is received then it stores
* into the session security parameters the new value. The server may use gnutls_session_certificate_type_get(),
* to access it.
*
* In case of a client: If a supported_eccs have been specified then we send the extension.
*
*/
static int
_gnutls_supported_ecc_recv_params (gnutls_session_t session,
const opaque * data, size_t _data_size)
{
int new_type = -1, ret, i;
ssize_t data_size = _data_size;
uint16_t len;
const opaque* p = data;
if (session->security_parameters.entity == GNUTLS_CLIENT)
{
/* A client shouldn't receive this extension */
return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION);
}
else
{ /* SERVER SIDE - we must check if the sent supported ecc type is the right one
*/
if (data_size < 2)
return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION);
DECR_LEN (data_size, 2);
len = _gnutls_read_uint16(p);
p += 2;
DECR_LEN (data_size, len);
for (i = 0; i < len; i+=2)
{
new_type = _gnutls_num_to_ecc (_gnutls_read_uint16(&p[i]));
if (new_type < 0)
continue;
/* Check if we support this supported_ecc */
if ((ret =
_gnutls_session_supports_ecc_curve (session, new_type)) < 0)
{
gnutls_assert ();
continue;
}
else
break;
/* new_type is ok */
}
if (new_type < 0)
{
gnutls_assert ();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
if ((ret =
_gnutls_session_supports_ecc_curve (session, new_type)) < 0)
{
/* The peer has requested unsupported ecc
* types. Instead of failing, procceed normally.
* (the ciphersuite selection would fail, or a
* non certificate ciphersuite will be selected).
*/
return gnutls_assert_val(0);
}
_gnutls_session_ecc_curve_set (session, new_type);
}
return 0;
}
/* returns data_size or a negative number on failure
*/
static int
_gnutls_supported_ecc_send_params (gnutls_session_t session, gnutls_buffer_st* extdata)
{
unsigned len, i;
int ret;
uint16_t p;
/* this extension is only being sent on client side */
if (session->security_parameters.entity == GNUTLS_CLIENT)
{
if (session->internals.priorities.supported_ecc.algorithms > 0)
{
len = session->internals.priorities.supported_ecc.algorithms;
/* this is a vector!
*/
ret = _gnutls_buffer_append_prefix(extdata, 16, len*2);
if (ret < 0)
return gnutls_assert_val(ret);
for (i = 0; i < len; i++)
{
p =
_gnutls_ecc_to_num (session->internals.priorities.
supported_ecc.priority[i]);
ret = _gnutls_buffer_append_prefix(extdata, 16, p);
if (ret < 0)
return gnutls_assert_val(ret);
}
return (len + 1)*2;
}
}
return 0;
}
/*
* In case of a server: if a SUPPORTED_ECC extension type is received then it stores
* into the session security parameters the new value. The server may use gnutls_session_certificate_type_get(),
* to access it.
*
* In case of a client: If a supported_eccs have been specified then we send the extension.
*
*/
static int
_gnutls_supported_ecc_pf_recv_params (gnutls_session_t session,
const opaque * data, size_t _data_size)
{
int len, i;
int uncompressed = 0;
int data_size = _data_size;
if (session->security_parameters.entity == GNUTLS_CLIENT)
{
if (data_size < 1)
return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION);
len = data[0];
DECR_LEN (data_size, len+1);
for (i=0;i<len;i++)
if (data[1+i] == 0) /* uncompressed */
uncompressed = 1;
if (uncompressed == 0)
return gnutls_assert_val(GNUTLS_E_UNKNOWN_PK_ALGORITHM);
}
else
{
/* only sanity check here. We only support uncompressed points
* and a client must support it thus nothing to check.
*/
if (_data_size < 1)
return gnutls_assert_val(GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION);
}
return 0;
}
/* returns data_size or a negative number on failure
*/
static int
_gnutls_supported_ecc_pf_send_params (gnutls_session_t session, gnutls_buffer_st* extdata)
{
const opaque p[2] = {0x01, 0x00}; /* only support uncompressed point format */
/* this extension is only being sent on client and server side */
_gnutls_buffer_append_data(extdata, p, 2);
return 2;
}
/* Maps numbers to record sizes according to the
* extensions draft.
*/
int
_gnutls_num_to_ecc (int num)
{
switch (num)
{
case 23:
/* sec256r1 */
return GNUTLS_ECC_CURVE_SECP256R1;
case 24:
return GNUTLS_ECC_CURVE_SECP384R1;
default:
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
}
/* Maps record size to numbers according to the
* extensions draft.
*/
int
_gnutls_ecc_to_num (ecc_curve_t supported_ecc)
{
switch (supported_ecc)
{
case GNUTLS_ECC_CURVE_SECP256R1:
return 23;
case GNUTLS_ECC_CURVE_SECP384R1:
return 24;
default:
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
}
/* Returns 0 if the given ECC curve is allowed in the current
* session. A negative error value is returned otherwise.
*/
int
_gnutls_session_supports_ecc_curve (gnutls_session_t session, int ecc_type)
{
unsigned i;
if (session->internals.priorities.supported_ecc.algorithms > 0)
{
for (i = 0; i < session->internals.priorities.supported_ecc.algorithms; i++)
{
if (session->internals.priorities.supported_ecc.priority[i] == ecc_type)
return 0;
}
}
return GNUTLS_E_ECC_NO_SUPPORTED_CURVES;
}
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