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/*
* Copyright (C) 2001 Nikos Mavroyanopoulos
*
* This file is part of GNUTLS.
*
* The GNUTLS library 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/* Functions to parse the SSLv2.0 hello message.
*/
#include "gnutls_int.h"
#include "gnutls_errors.h"
#include "gnutls_dh.h"
#include "debug.h"
#include "gnutls_algorithms.h"
#include "gnutls_compress.h"
#include "gnutls_cipher.h"
#include "gnutls_buffers.h"
#include "gnutls_kx.h"
#include "gnutls_handshake.h"
#include "gnutls_num.h"
#include "gnutls_hash_int.h"
#include "gnutls_db.h"
#include "gnutls_extensions.h"
#include "gnutls_random.h"
#include "gnutls_auth_int.h"
/* This selects the best supported ciphersuite from the ones provided */
static int _gnutls_handshake_select_v2_suite(gnutls_session session, char *data, int datalen)
{
int i, j, ret;
char* _data;
int _datalen;
_data = gnutls_malloc( datalen);
if (_data==NULL) {
gnutls_assert();
return GNUTLS_E_MEMORY_ERROR;
}
_gnutls_handshake_log( "HSK: Parsing a version 2.0 client hello.\n");
i = _datalen = 0;
for (j = 0; j < datalen; j += 3) {
if (data[j] == 0) {
memcpy( &_data[i], &data[j+1], 2);
i+=2;
_datalen+=2;
}
}
ret = _gnutls_server_select_suite( session, _data, _datalen);
gnutls_free(_data);
return ret;
}
/* Read a v2 client hello. Some browsers still use that beast!
* However they set their version to 3.0 or 3.1.
*/
int _gnutls_read_client_hello_v2(gnutls_session session, opaque * data,
int datalen)
{
uint16 session_id_len = 0;
int pos = 0;
int ret = 0;
uint16 sizeOfSuites;
gnutls_protocol_version version;
opaque random[TLS_RANDOM_SIZE];
int len = datalen;
int err;
uint16 challenge;
opaque session_id[TLS_MAX_SESSION_ID_SIZE];
gnutls_protocol_version ver;
/* we only want to get here once - only in client hello */
session->internals.v2_hello = 0;
DECR_LEN(len, 2);
_gnutls_handshake_log( "HSK: SSL 2.0 Hello: Client's version: %d.%d\n", data[pos],
data[pos + 1]);
set_adv_version( session, data[pos], data[pos+1]);
version = _gnutls_version_get(data[pos], data[pos + 1]);
/* if we do not support that version */
if (_gnutls_version_is_supported(session, version) == 0) {
ver = _gnutls_version_lowest( session);
} else {
ver = version;
}
if (ver==GNUTLS_VERSION_UNKNOWN || ver > version) {
gnutls_assert();
return GNUTLS_E_UNSUPPORTED_VERSION_PACKET;
}
_gnutls_set_current_version(session, ver);
pos += 2;
/* Read uint16 cipher_spec_length */
DECR_LEN(len, 2);
sizeOfSuites = _gnutls_read_uint16( &data[pos]);
pos += 2;
/* read session id length */
DECR_LEN(len, 2);
session_id_len = _gnutls_read_uint16( &data[pos]);
pos += 2;
if (session_id_len > TLS_MAX_SESSION_ID_SIZE) {
gnutls_assert();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
/* read challenge length */
DECR_LEN(len, 2);
challenge = _gnutls_read_uint16( &data[pos]);
pos += 2;
if ( challenge < 16 || challenge > TLS_RANDOM_SIZE) {
gnutls_assert();
return GNUTLS_E_UNSUPPORTED_VERSION_PACKET;
}
/* find an appropriate cipher suite */
DECR_LEN(len, sizeOfSuites);
ret = _gnutls_handshake_select_v2_suite(session, &data[pos], sizeOfSuites);
pos += sizeOfSuites;
if (ret < 0) {
gnutls_assert();
return ret;
}
/* check if the credentials (username, public key etc. are ok)
*/
if (_gnutls_get_kx_cred( session->gnutls_key, _gnutls_cipher_suite_get_kx_algo(session->security_parameters.current_cipher_suite), &err) == NULL && err != 0) {
gnutls_assert();
return GNUTLS_E_INSUFICIENT_CRED;
}
/* set the MOD_AUTH_STRUCT to the appropriate struct
* according to the KX algorithm. This is needed since all the
* handshake functions are read from there;
*/
session->internals.auth_struct =
_gnutls_kx_auth_struct(_gnutls_cipher_suite_get_kx_algo
(session->security_parameters.
current_cipher_suite));
if (session->internals.auth_struct == NULL) {
_gnutls_handshake_log(
"HSK: SSL 2.0 Hello: Cannot find the appropriate handler for the KX algorithm\n");
gnutls_assert();
return GNUTLS_E_UNKNOWN_CIPHER_TYPE;
}
/* read random new values -skip session id for now */
DECR_LEN(len, session_id_len); /* skip session id for now */
memcpy( session_id, &data[pos], session_id_len);
pos+=session_id_len;
DECR_LEN(len, challenge);
memset( random, 0, TLS_RANDOM_SIZE);
memcpy( &random[TLS_RANDOM_SIZE-challenge], &data[pos], challenge);
_gnutls_set_client_random( session, random);
/* generate server random value */
_gnutls_create_random( random);
_gnutls_set_server_random( session, random);
session->security_parameters.timestamp = time(NULL);
/* RESUME SESSION */
DECR_LEN(len, session_id_len);
ret = _gnutls_server_restore_session(session, session_id, session_id_len);
if (ret == 0) { /* resumed! */
/* get the new random values */
memcpy(session->internals.resumed_security_parameters.server_random,
session->security_parameters.server_random, TLS_RANDOM_SIZE);
memcpy(session->internals.resumed_security_parameters.client_random,
session->security_parameters.client_random, TLS_RANDOM_SIZE);
session->internals.resumed = RESUME_TRUE;
return 0;
} else {
_gnutls_generate_session_id(session->security_parameters.
session_id,
&session->security_parameters.
session_id_size);
session->internals.resumed = RESUME_FALSE;
}
session->internals.compression_method = GNUTLS_COMP_NULL;
return 0;
}
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