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/*
* eap_md5.c EAP MD5 functionality.
*
* Version: $Id$
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*
* Copyright 2000,2001,2006 The FreeRADIUS server project
* Copyright 2001 hereUare Communications, Inc. <raghud@hereuare.com>
*/
/*
*
* MD5 Packet Format in EAP Type-Data
* --- ------ ------ -- --- ---------
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Value-Size | Value ...
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Name ...
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
*/
RCSID("$Id$")
#include <stdio.h>
#include <stdlib.h>
#include "eap.h"
#include "eap_md5.h"
#include <freeradius-devel/md5.h>
/*
* We expect only RESPONSE for which SUCCESS or FAILURE is sent back
*/
MD5_PACKET *eapmd5_extract(EAP_DS *eap_ds)
{
md5_packet_t *data;
MD5_PACKET *packet;
unsigned short name_len;
/*
* We need a response, of type EAP-MD5, with at least
* one byte of type data (EAP-MD5) following the 4-byte
* EAP-Packet header.
*/
if (!eap_ds ||
!eap_ds->response ||
(eap_ds->response->code != PW_MD5_RESPONSE) ||
eap_ds->response->type.num != PW_EAP_MD5 ||
!eap_ds->response->type.data ||
(eap_ds->response->length <= MD5_HEADER_LEN) ||
(eap_ds->response->type.data[0] <= 0)) {
ERROR("rlm_eap_md5: corrupted data");
return NULL;
}
packet = talloc_zero(eap_ds, MD5_PACKET);
if (!packet) return NULL;
/*
* Code & id for MD5 & EAP are same
*
* but md5_length = length of the EAP-MD5 data, which
* doesn't include the EAP header, or the octet saying
* EAP-MD5.
*/
packet->code = eap_ds->response->code;
packet->id = eap_ds->response->id;
packet->length = eap_ds->response->length - (MD5_HEADER_LEN + 1);
/*
* Sanity check the EAP-MD5 packet sent to us
* by the client.
*/
data = (md5_packet_t *)eap_ds->response->type.data;
/*
* Already checked the size above.
*/
packet->value_size = data->value_size;
/*
* Allocate room for the data, and copy over the data.
*/
packet->value = talloc_array(packet, uint8_t, packet->value_size);
if (!packet->value) {
talloc_free(packet);
return NULL;
}
memcpy(packet->value, data->value_name, packet->value_size);
/*
* Name is optional and is present after Value, but we
* need to check for it, as eapmd5_compose()
*/
name_len = packet->length - (packet->value_size + 1);
if (name_len) {
packet->name = talloc_array(packet, char, name_len + 1);
if (!packet->name) {
talloc_free(packet);
return NULL;
}
memcpy(packet->name, data->value_name + packet->value_size,
name_len);
packet->name[name_len] = 0;
}
return packet;
}
/*
* verify = MD5(id+password+challenge_sent)
*/
int eapmd5_verify(MD5_PACKET *packet, VALUE_PAIR* password,
uint8_t *challenge)
{
char *ptr;
char string[1 + MAX_STRING_LEN*2];
uint8_t digest[16];
unsigned short len;
/*
* Sanity check it.
*/
if (packet->value_size != 16) {
ERROR("rlm_eap_md5: Expected 16 bytes of response to challenge, got %d", packet->value_size);
return 0;
}
len = 0;
ptr = string;
/*
* This is really rad_chap_pwencode()...
*/
*ptr++ = packet->id;
len++;
memcpy(ptr, password->vp_strvalue, password->vp_length);
ptr += password->vp_length;
len += password->vp_length;
/*
* The challenge size is hard-coded.
*/
memcpy(ptr, challenge, MD5_CHALLENGE_LEN);
len += MD5_CHALLENGE_LEN;
fr_md5_calc(digest, (u_char *)string, len);
/*
* The length of the response is always 16 for MD5.
*/
if (rad_digest_cmp(digest, packet->value, 16) != 0) {
DEBUG("EAP-MD5 digests do not match.");
return 0;
}
return 1;
}
/*
* Compose the portions of the reply packet specific to the
* EAP-MD5 protocol, in the EAP reply typedata
*/
int eapmd5_compose(EAP_DS *eap_ds, MD5_PACKET *reply)
{
uint8_t *ptr;
unsigned short name_len;
/*
* We really only send Challenge (EAP-Identity),
* and EAP-Success, and EAP-Failure.
*/
if (reply->code < 3) {
eap_ds->request->type.num = PW_EAP_MD5;
rad_assert(reply->length > 0);
eap_ds->request->type.data = talloc_array(eap_ds->request,
uint8_t,
reply->length);
if (!eap_ds->request->type.data) {
talloc_free(reply);
return 0;
}
ptr = eap_ds->request->type.data;
*ptr++ = (uint8_t)(reply->value_size & 0xFF);
memcpy(ptr, reply->value, reply->value_size);
/* Just the Challenge length */
eap_ds->request->type.length = reply->value_size + 1;
/*
* Return the name, if necessary.
*
* Don't see why this is *ever* necessary...
*/
name_len = reply->length - (reply->value_size + 1);
if (name_len && reply->name) {
ptr += reply->value_size;
memcpy(ptr, reply->name, name_len);
/* Challenge length + Name length */
eap_ds->request->type.length += name_len;
}
} else {
eap_ds->request->type.length = 0;
/* TODO: In future we might add message here wrt rfc1994 */
}
eap_ds->request->code = reply->code;
talloc_free(reply);
return 1;
}
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