[eap] Allow MD5-Challenge authentication method to be disabled

RFC 3748 states that implementations must support the MD5-Challenge
method.  However, some network environments may wish to disable it as
a matter of policy.

Allow support for MD5-Challenge to be controllable via the build
configuration option EAP_METHOD_MD5 in config/general.h.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/1163/head
Michael Brown 2024-02-23 12:33:57 +00:00
parent 834f319f87
commit 25ffcd79bf
6 changed files with 172 additions and 82 deletions

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@ -0,0 +1,39 @@
/*
* 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 Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <config/general.h>
/** @file
*
* EAP configuration options
*
*/
PROVIDE_REQUIRING_SYMBOL();
/*
* Drag in EAP authentication methods
*/
#ifdef EAP_METHOD_MD5
REQUIRE_OBJECT ( eap_md5 );
#endif

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@ -91,6 +91,12 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define CRYPTO_80211_WPA /* WPA Personal, authenticating with passphrase */
#define CRYPTO_80211_WPA2 /* Add support for stronger WPA cryptography */
/*
* 802.1x EAP authentication methods
*
*/
#define EAP_METHOD_MD5 /* MD5-Challenge port authentication */
/*
* Name resolution modules
*

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@ -166,6 +166,8 @@ struct eap_method {
/** Declare an EAP method */
#define __eap_method __table_entry ( EAP_METHODS, 01 )
extern int eap_tx_response ( struct eap_supplicant *supplicant,
const void *rsp, size_t rsp_len );
extern int eap_rx ( struct eap_supplicant *supplicant,
const void *data, size_t len );

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@ -297,6 +297,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define ERRFILE_httpntlm ( ERRFILE_NET | 0x004a0000 )
#define ERRFILE_eap ( ERRFILE_NET | 0x004b0000 )
#define ERRFILE_lldp ( ERRFILE_NET | 0x004c0000 )
#define ERRFILE_eap_md5 ( ERRFILE_NET | 0x004d0000 )
#define ERRFILE_image ( ERRFILE_IMAGE | 0x00000000 )
#define ERRFILE_elf ( ERRFILE_IMAGE | 0x00010000 )

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@ -28,8 +28,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <string.h>
#include <byteswap.h>
#include <ipxe/netdevice.h>
#include <ipxe/md5.h>
#include <ipxe/chap.h>
#include <ipxe/eap.h>
/** @file
@ -46,8 +44,8 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
* @v rsp_len Length of response type data
* @ret rc Return status code
*/
static int eap_tx_response ( struct eap_supplicant *supplicant,
const void *rsp, size_t rsp_len ) {
int eap_tx_response ( struct eap_supplicant *supplicant,
const void *rsp, size_t rsp_len ) {
struct net_device *netdev = supplicant->netdev;
struct eap_message *msg;
size_t len;
@ -167,84 +165,6 @@ struct eap_method eap_identity_method __eap_method = {
.rx = eap_rx_identity,
};
/**
* Handle EAP MD5-Challenge
*
* @v req Request type data
* @v req_len Length of request type data
* @ret rc Return status code
*/
static int eap_rx_md5 ( struct eap_supplicant *supplicant,
const void *req, size_t req_len ) {
struct net_device *netdev = supplicant->netdev;
const struct eap_md5 *md5req = req;
struct {
uint8_t len;
uint8_t value[MD5_DIGEST_SIZE];
} __attribute__ (( packed )) md5rsp;
struct chap_response chap;
void *secret;
int secret_len;
int rc;
/* Sanity checks */
if ( req_len < sizeof ( *md5req ) ) {
DBGC ( netdev, "EAP %s underlength MD5-Challenge:\n",
netdev->name );
DBGC_HDA ( netdev, 0, req, req_len );
rc = -EINVAL;
goto err_sanity;
}
if ( ( req_len - sizeof ( *md5req ) ) < md5req->len ) {
DBGC ( netdev, "EAP %s truncated MD5-Challenge:\n",
netdev->name );
DBGC_HDA ( netdev, 0, req, req_len );
rc = -EINVAL;
goto err_sanity;
}
/* Construct response */
if ( ( rc = chap_init ( &chap, &md5_algorithm ) ) != 0 ) {
DBGC ( netdev, "EAP %s could not initialise CHAP: %s\n",
netdev->name, strerror ( rc ) );
goto err_chap;
}
chap_set_identifier ( &chap, supplicant->id );
secret_len = fetch_raw_setting_copy ( netdev_settings ( netdev ),
&password_setting, &secret );
if ( secret_len < 0 ) {
rc = secret_len;
DBGC ( netdev, "EAP %s has no secret: %s\n",
netdev->name, strerror ( rc ) );
goto err_secret;
}
chap_update ( &chap, secret, secret_len );
chap_update ( &chap, md5req->value, md5req->len );
chap_respond ( &chap );
assert ( chap.response_len == sizeof ( md5rsp.value ) );
md5rsp.len = sizeof ( md5rsp.value );
memcpy ( md5rsp.value, chap.response, sizeof ( md5rsp.value ) );
/* Transmit response */
if ( ( rc = eap_tx_response ( supplicant, &md5rsp,
sizeof ( md5rsp ) ) ) != 0 )
goto err_tx;
err_tx:
free ( secret );
err_secret:
chap_finish ( &chap );
err_chap:
err_sanity:
return rc;
}
/** EAP MD5-Challenge method */
struct eap_method eap_md5_method __eap_method = {
.type = EAP_TYPE_MD5,
.rx = eap_rx_md5,
};
/**
* Handle EAP Request
*
@ -370,3 +290,9 @@ int eap_rx ( struct eap_supplicant *supplicant, const void *data,
return -ENOTSUP;
}
}
/* Drag in objects via eap_rx() */
REQUIRING_SYMBOL ( eap_rx );
/* Drag in EAP configuration */
REQUIRE_OBJECT ( config_eap );

116
src/net/eap_md5.c 100644
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@ -0,0 +1,116 @@
/*
* Copyright (C) 2024 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 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 Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ipxe/md5.h>
#include <ipxe/chap.h>
#include <ipxe/eap.h>
/** @file
*
* EAP MD5-Challenge authentication method
*
*/
/**
* Handle EAP MD5-Challenge
*
* @v supplicant EAP supplicant
* @v req Request type data
* @v req_len Length of request type data
* @ret rc Return status code
*/
static int eap_rx_md5 ( struct eap_supplicant *supplicant,
const void *req, size_t req_len ) {
struct net_device *netdev = supplicant->netdev;
const struct eap_md5 *md5req = req;
struct {
uint8_t len;
uint8_t value[MD5_DIGEST_SIZE];
} __attribute__ (( packed )) md5rsp;
struct chap_response chap;
void *secret;
int secret_len;
int rc;
/* Sanity checks */
if ( req_len < sizeof ( *md5req ) ) {
DBGC ( netdev, "EAP %s underlength MD5-Challenge:\n",
netdev->name );
DBGC_HDA ( netdev, 0, req, req_len );
rc = -EINVAL;
goto err_sanity;
}
if ( ( req_len - sizeof ( *md5req ) ) < md5req->len ) {
DBGC ( netdev, "EAP %s truncated MD5-Challenge:\n",
netdev->name );
DBGC_HDA ( netdev, 0, req, req_len );
rc = -EINVAL;
goto err_sanity;
}
/* Construct response */
if ( ( rc = chap_init ( &chap, &md5_algorithm ) ) != 0 ) {
DBGC ( netdev, "EAP %s could not initialise CHAP: %s\n",
netdev->name, strerror ( rc ) );
goto err_chap;
}
chap_set_identifier ( &chap, supplicant->id );
secret_len = fetch_raw_setting_copy ( netdev_settings ( netdev ),
&password_setting, &secret );
if ( secret_len < 0 ) {
rc = secret_len;
DBGC ( netdev, "EAP %s has no secret: %s\n",
netdev->name, strerror ( rc ) );
goto err_secret;
}
chap_update ( &chap, secret, secret_len );
chap_update ( &chap, md5req->value, md5req->len );
chap_respond ( &chap );
assert ( chap.response_len == sizeof ( md5rsp.value ) );
md5rsp.len = sizeof ( md5rsp.value );
memcpy ( md5rsp.value, chap.response, sizeof ( md5rsp.value ) );
/* Transmit response */
if ( ( rc = eap_tx_response ( supplicant, &md5rsp,
sizeof ( md5rsp ) ) ) != 0 )
goto err_tx;
err_tx:
free ( secret );
err_secret:
chap_finish ( &chap );
err_chap:
err_sanity:
return rc;
}
/** EAP MD5-Challenge method */
struct eap_method eap_md5_method __eap_method = {
.type = EAP_TYPE_MD5,
.rx = eap_rx_md5,
};