freebsd-dev/contrib/hostapd/eap_mschapv2.c
2007-07-09 16:15:06 +00:00

556 lines
14 KiB
C

/*
* hostapd / EAP-MSCHAPv2 (draft-kamath-pppext-eap-mschapv2-00.txt) server
* Copyright (c) 2004-2007, Jouni Malinen <j@w1.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include "hostapd.h"
#include "common.h"
#include "eap_i.h"
#include "ms_funcs.h"
struct eap_mschapv2_hdr {
u8 op_code; /* MSCHAPV2_OP_* */
u8 mschapv2_id; /* must be changed for challenges, but not for
* success/failure */
u8 ms_length[2]; /* Note: misaligned; length - 5 */
/* followed by data */
} STRUCT_PACKED;
#define MSCHAPV2_OP_CHALLENGE 1
#define MSCHAPV2_OP_RESPONSE 2
#define MSCHAPV2_OP_SUCCESS 3
#define MSCHAPV2_OP_FAILURE 4
#define MSCHAPV2_OP_CHANGE_PASSWORD 7
#define MSCHAPV2_RESP_LEN 49
#define ERROR_RESTRICTED_LOGON_HOURS 646
#define ERROR_ACCT_DISABLED 647
#define ERROR_PASSWD_EXPIRED 648
#define ERROR_NO_DIALIN_PERMISSION 649
#define ERROR_AUTHENTICATION_FAILURE 691
#define ERROR_CHANGING_PASSWORD 709
#define PASSWD_CHANGE_CHAL_LEN 16
#define MSCHAPV2_KEY_LEN 16
#define CHALLENGE_LEN 16
struct eap_mschapv2_data {
u8 auth_challenge[CHALLENGE_LEN];
u8 auth_response[20];
enum { CHALLENGE, SUCCESS_REQ, FAILURE_REQ, SUCCESS, FAILURE } state;
u8 resp_mschapv2_id;
u8 master_key[16];
int master_key_valid;
};
static void * eap_mschapv2_init(struct eap_sm *sm)
{
struct eap_mschapv2_data *data;
data = wpa_zalloc(sizeof(*data));
if (data == NULL)
return NULL;
data->state = CHALLENGE;
return data;
}
static void eap_mschapv2_reset(struct eap_sm *sm, void *priv)
{
struct eap_mschapv2_data *data = priv;
free(data);
}
static u8 * eap_mschapv2_build_challenge(struct eap_sm *sm,
struct eap_mschapv2_data *data,
int id, size_t *reqDataLen)
{
struct eap_hdr *req;
struct eap_mschapv2_hdr *ms;
u8 *pos;
char *name = "hostapd"; /* TODO: make this configurable */
size_t ms_len;
if (hostapd_get_rand(data->auth_challenge, CHALLENGE_LEN)) {
wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to get random "
"data");
data->state = FAILURE;
return NULL;
}
ms_len = sizeof(*ms) + 1 + CHALLENGE_LEN + strlen(name);
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, reqDataLen,
ms_len, EAP_CODE_REQUEST, id, &pos);
if (req == NULL) {
wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to allocate memory"
" for request");
data->state = FAILURE;
return NULL;
}
ms = (struct eap_mschapv2_hdr *) pos;
ms->op_code = MSCHAPV2_OP_CHALLENGE;
ms->mschapv2_id = id;
WPA_PUT_BE16(ms->ms_length, ms_len);
pos = (u8 *) (ms + 1);
*pos++ = CHALLENGE_LEN;
memcpy(pos, data->auth_challenge, CHALLENGE_LEN);
wpa_hexdump(MSG_MSGDUMP, "EAP-MSCHAPV2: Challenge", pos,
CHALLENGE_LEN);
pos += CHALLENGE_LEN;
memcpy(pos, name, strlen(name));
return (u8 *) req;
}
static u8 * eap_mschapv2_build_success_req(struct eap_sm *sm,
struct eap_mschapv2_data *data,
int id, size_t *reqDataLen)
{
struct eap_hdr *req;
struct eap_mschapv2_hdr *ms;
u8 *pos, *msg;
char *message = "OK";
size_t ms_len;
ms_len = sizeof(*ms) + 2 + 2 * sizeof(data->auth_response) + 1 + 2 +
strlen(message);
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, reqDataLen,
ms_len, EAP_CODE_REQUEST, id, &pos);
if (req == NULL) {
wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to allocate memory"
" for request");
data->state = FAILURE;
return NULL;
}
ms = (struct eap_mschapv2_hdr *) pos;
ms->op_code = MSCHAPV2_OP_SUCCESS;
ms->mschapv2_id = data->resp_mschapv2_id;
WPA_PUT_BE16(ms->ms_length, ms_len);
msg = pos = (u8 *) (ms + 1);
*pos++ = 'S';
*pos++ = '=';
pos += wpa_snprintf_hex_uppercase((char *) pos,
sizeof(data->auth_response) * 2 + 1,
data->auth_response,
sizeof(data->auth_response));
*pos++ = ' ';
*pos++ = 'M';
*pos++ = '=';
memcpy(pos, message, strlen(message));
wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-MSCHAPV2: Success Request Message",
msg, ms_len - sizeof(*ms));
return (u8 *) req;
}
static u8 * eap_mschapv2_build_failure_req(struct eap_sm *sm,
struct eap_mschapv2_data *data,
int id, size_t *reqDataLen)
{
struct eap_hdr *req;
struct eap_mschapv2_hdr *ms;
u8 *pos;
char *message = "E=691 R=0 C=00000000000000000000000000000000 V=3 "
"M=FAILED";
size_t ms_len;
ms_len = sizeof(*ms) + strlen(message);
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2, reqDataLen,
ms_len, EAP_CODE_REQUEST, id, &pos);
if (req == NULL) {
wpa_printf(MSG_ERROR, "EAP-MSCHAPV2: Failed to allocate memory"
" for request");
data->state = FAILURE;
return NULL;
}
ms = (struct eap_mschapv2_hdr *) pos;
ms->op_code = MSCHAPV2_OP_FAILURE;
ms->mschapv2_id = data->resp_mschapv2_id;
WPA_PUT_BE16(ms->ms_length, ms_len);
memcpy((u8 *) (ms + 1), message, strlen(message));
wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-MSCHAPV2: Failure Request Message",
(u8 *) message, strlen(message));
return (u8 *) req;
}
static u8 * eap_mschapv2_buildReq(struct eap_sm *sm, void *priv, int id,
size_t *reqDataLen)
{
struct eap_mschapv2_data *data = priv;
switch (data->state) {
case CHALLENGE:
return eap_mschapv2_build_challenge(sm, data, id, reqDataLen);
case SUCCESS_REQ:
return eap_mschapv2_build_success_req(sm, data, id,
reqDataLen);
case FAILURE_REQ:
return eap_mschapv2_build_failure_req(sm, data, id,
reqDataLen);
default:
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Unknown state %d in "
"buildReq", data->state);
break;
}
return NULL;
}
static Boolean eap_mschapv2_check(struct eap_sm *sm, void *priv,
u8 *respData, size_t respDataLen)
{
struct eap_mschapv2_data *data = priv;
struct eap_mschapv2_hdr *resp;
const u8 *pos;
size_t len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2,
respData, respDataLen, &len);
if (pos == NULL || len < 1) {
wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Invalid frame");
return TRUE;
}
resp = (struct eap_mschapv2_hdr *) pos;
if (data->state == CHALLENGE &&
resp->op_code != MSCHAPV2_OP_RESPONSE) {
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Expected Response - "
"ignore op %d", resp->op_code);
return TRUE;
}
if (data->state == SUCCESS_REQ &&
resp->op_code != MSCHAPV2_OP_SUCCESS &&
resp->op_code != MSCHAPV2_OP_FAILURE) {
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Expected Success or "
"Failure - ignore op %d", resp->op_code);
return TRUE;
}
if (data->state == FAILURE_REQ &&
resp->op_code != MSCHAPV2_OP_FAILURE) {
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Expected Failure "
"- ignore op %d", resp->op_code);
return TRUE;
}
return FALSE;
}
static void eap_mschapv2_process_response(struct eap_sm *sm,
struct eap_mschapv2_data *data,
u8 *respData, size_t respDataLen)
{
struct eap_mschapv2_hdr *resp;
const u8 *pos, *end, *peer_challenge, *nt_response, *name;
u8 flags;
size_t len, name_len, i;
u8 expected[24];
const u8 *username, *user;
size_t username_len, user_len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2,
respData, respDataLen, &len);
if (pos == NULL || len < 1)
return; /* Should not happen - frame already validated */
end = pos + len;
resp = (struct eap_mschapv2_hdr *) pos;
pos = (u8 *) (resp + 1);
if (len < sizeof(*resp) + 1 + 49 ||
resp->op_code != MSCHAPV2_OP_RESPONSE ||
pos[0] != 49) {
wpa_hexdump(MSG_DEBUG, "EAP-MSCHAPV2: Invalid response",
respData, respDataLen);
data->state = FAILURE;
return;
}
data->resp_mschapv2_id = resp->mschapv2_id;
pos++;
peer_challenge = pos;
pos += 16 + 8;
nt_response = pos;
pos += 24;
flags = *pos++;
name = pos;
name_len = end - name;
wpa_hexdump(MSG_MSGDUMP, "EAP-MSCHAPV2: Peer-Challenge",
peer_challenge, 16);
wpa_hexdump(MSG_MSGDUMP, "EAP-MSCHAPV2: NT-Response", nt_response, 24);
wpa_printf(MSG_MSGDUMP, "EAP-MSCHAPV2: Flags 0x%x", flags);
wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-MSCHAPV2: Name", name, name_len);
/* MSCHAPv2 does not include optional domain name in the
* challenge-response calculation, so remove domain prefix
* (if present). */
username = sm->identity;
username_len = sm->identity_len;
for (i = 0; i < username_len; i++) {
if (username[i] == '\\') {
username_len -= i + 1;
username += i + 1;
break;
}
}
user = name;
user_len = name_len;
for (i = 0; i < user_len; i++) {
if (user[i] == '\\') {
user_len -= i + 1;
user += i + 1;
break;
}
}
if (username_len != user_len ||
memcmp(username, user, username_len) != 0) {
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Mismatch in user names");
wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Expected user "
"name", username, username_len);
wpa_hexdump_ascii(MSG_DEBUG, "EAP-MSCHAPV2: Received user "
"name", user, user_len);
data->state = FAILURE;
return;
}
wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-MSCHAPV2: User name",
username, username_len);
if (sm->user->password_hash) {
generate_nt_response_pwhash(data->auth_challenge,
peer_challenge,
username, username_len,
sm->user->password,
expected);
} else {
generate_nt_response(data->auth_challenge, peer_challenge,
username, username_len,
sm->user->password,
sm->user->password_len,
expected);
}
if (memcmp(nt_response, expected, 24) == 0) {
const u8 *pw_hash;
u8 pw_hash_buf[16], pw_hash_hash[16];
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Correct NT-Response");
data->state = SUCCESS_REQ;
/* Authenticator response is not really needed yet, but
* calculate it here so that peer_challenge and username need
* not be saved. */
if (sm->user->password_hash) {
pw_hash = sm->user->password;
generate_authenticator_response_pwhash(
sm->user->password, peer_challenge,
data->auth_challenge, username, username_len,
nt_response, data->auth_response);
} else {
nt_password_hash(sm->user->password,
sm->user->password_len,
pw_hash_buf);
pw_hash = pw_hash_buf;
generate_authenticator_response(sm->user->password,
sm->user->password_len,
peer_challenge,
data->auth_challenge,
username, username_len,
nt_response,
data->auth_response);
}
hash_nt_password_hash(pw_hash, pw_hash_hash);
get_master_key(pw_hash_hash, nt_response, data->master_key);
data->master_key_valid = 1;
wpa_hexdump_key(MSG_DEBUG, "EAP-MSCHAPV2: Derived Master Key",
data->master_key, MSCHAPV2_KEY_LEN);
} else {
wpa_hexdump(MSG_MSGDUMP, "EAP-MSCHAPV2: Expected NT-Response",
expected, 24);
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Invalid NT-Response");
data->state = FAILURE_REQ;
}
}
static void eap_mschapv2_process_success_resp(struct eap_sm *sm,
struct eap_mschapv2_data *data,
u8 *respData, size_t respDataLen)
{
struct eap_mschapv2_hdr *resp;
const u8 *pos;
size_t len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2,
respData, respDataLen, &len);
if (pos == NULL || len < 1)
return; /* Should not happen - frame already validated */
resp = (struct eap_mschapv2_hdr *) pos;
if (resp->op_code == MSCHAPV2_OP_SUCCESS) {
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received Success Response"
" - authentication completed successfully");
data->state = SUCCESS;
} else {
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Did not receive Success "
"Response - peer rejected authentication");
data->state = FAILURE;
}
}
static void eap_mschapv2_process_failure_resp(struct eap_sm *sm,
struct eap_mschapv2_data *data,
u8 *respData, size_t respDataLen)
{
struct eap_mschapv2_hdr *resp;
const u8 *pos;
size_t len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2,
respData, respDataLen, &len);
if (pos == NULL || len < 1)
return; /* Should not happen - frame already validated */
resp = (struct eap_mschapv2_hdr *) pos;
if (resp->op_code == MSCHAPV2_OP_FAILURE) {
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Received Failure Response"
" - authentication failed");
} else {
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Did not receive Failure "
"Response - authentication failed");
}
data->state = FAILURE;
}
static void eap_mschapv2_process(struct eap_sm *sm, void *priv,
u8 *respData, size_t respDataLen)
{
struct eap_mschapv2_data *data = priv;
if (sm->user == NULL || sm->user->password == NULL) {
wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Password not configured");
data->state = FAILURE;
return;
}
switch (data->state) {
case CHALLENGE:
eap_mschapv2_process_response(sm, data, respData, respDataLen);
break;
case SUCCESS_REQ:
eap_mschapv2_process_success_resp(sm, data, respData,
respDataLen);
break;
case FAILURE_REQ:
eap_mschapv2_process_failure_resp(sm, data, respData,
respDataLen);
break;
default:
wpa_printf(MSG_DEBUG, "EAP-MSCHAPV2: Unknown state %d in "
"process", data->state);
break;
}
}
static Boolean eap_mschapv2_isDone(struct eap_sm *sm, void *priv)
{
struct eap_mschapv2_data *data = priv;
return data->state == SUCCESS || data->state == FAILURE;
}
static u8 * eap_mschapv2_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
struct eap_mschapv2_data *data = priv;
u8 *key;
if (data->state != SUCCESS || !data->master_key_valid)
return NULL;
*len = 2 * MSCHAPV2_KEY_LEN;
key = malloc(*len);
if (key == NULL)
return NULL;
get_asymetric_start_key(data->master_key, key, MSCHAPV2_KEY_LEN, 0, 0);
get_asymetric_start_key(data->master_key, key + MSCHAPV2_KEY_LEN,
MSCHAPV2_KEY_LEN, 1, 0);
wpa_hexdump_key(MSG_DEBUG, "EAP-MSCHAPV2: Derived key", key, *len);
return key;
}
static Boolean eap_mschapv2_isSuccess(struct eap_sm *sm, void *priv)
{
struct eap_mschapv2_data *data = priv;
return data->state == SUCCESS;
}
int eap_server_mschapv2_register(void)
{
struct eap_method *eap;
int ret;
eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
EAP_VENDOR_IETF, EAP_TYPE_MSCHAPV2,
"MSCHAPV2");
if (eap == NULL)
return -1;
eap->init = eap_mschapv2_init;
eap->reset = eap_mschapv2_reset;
eap->buildReq = eap_mschapv2_buildReq;
eap->check = eap_mschapv2_check;
eap->process = eap_mschapv2_process;
eap->isDone = eap_mschapv2_isDone;
eap->getKey = eap_mschapv2_getKey;
eap->isSuccess = eap_mschapv2_isSuccess;
ret = eap_server_method_register(eap);
if (ret)
eap_server_method_free(eap);
return ret;
}