hostap/src/eap_server/eap_server_md5.c
Jouni Malinen 305dbc9870 EAP-MD5: Verify that CHAP operation succeeds
The MD5 operation may be disabled in the security policy so chap_md5()
call can fail.

Signed-hostap: Jouni Malinen <j@w1.fi>
2012-08-16 18:49:02 +03:00

175 lines
3.9 KiB
C

/*
* hostapd / EAP-MD5 server
* Copyright (c) 2004-2012, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto/random.h"
#include "eap_i.h"
#include "eap_common/chap.h"
#define CHALLENGE_LEN 16
struct eap_md5_data {
u8 challenge[CHALLENGE_LEN];
enum { CONTINUE, SUCCESS, FAILURE } state;
};
static void * eap_md5_init(struct eap_sm *sm)
{
struct eap_md5_data *data;
data = os_zalloc(sizeof(*data));
if (data == NULL)
return NULL;
data->state = CONTINUE;
return data;
}
static void eap_md5_reset(struct eap_sm *sm, void *priv)
{
struct eap_md5_data *data = priv;
os_free(data);
}
static struct wpabuf * eap_md5_buildReq(struct eap_sm *sm, void *priv, u8 id)
{
struct eap_md5_data *data = priv;
struct wpabuf *req;
if (random_get_bytes(data->challenge, CHALLENGE_LEN)) {
wpa_printf(MSG_ERROR, "EAP-MD5: Failed to get random data");
data->state = FAILURE;
return NULL;
}
req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MD5, 1 + CHALLENGE_LEN,
EAP_CODE_REQUEST, id);
if (req == NULL) {
wpa_printf(MSG_ERROR, "EAP-MD5: Failed to allocate memory for "
"request");
data->state = FAILURE;
return NULL;
}
wpabuf_put_u8(req, CHALLENGE_LEN);
wpabuf_put_data(req, data->challenge, CHALLENGE_LEN);
wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Challenge", data->challenge,
CHALLENGE_LEN);
data->state = CONTINUE;
return req;
}
static Boolean eap_md5_check(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
const u8 *pos;
size_t len;
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &len);
if (pos == NULL || len < 1) {
wpa_printf(MSG_INFO, "EAP-MD5: Invalid frame");
return TRUE;
}
if (*pos != CHAP_MD5_LEN || 1 + CHAP_MD5_LEN > len) {
wpa_printf(MSG_INFO, "EAP-MD5: Invalid response "
"(response_len=%d payload_len=%lu",
*pos, (unsigned long) len);
return TRUE;
}
return FALSE;
}
static void eap_md5_process(struct eap_sm *sm, void *priv,
struct wpabuf *respData)
{
struct eap_md5_data *data = priv;
const u8 *pos;
size_t plen;
u8 hash[CHAP_MD5_LEN], id;
if (sm->user == NULL || sm->user->password == NULL ||
sm->user->password_hash) {
wpa_printf(MSG_INFO, "EAP-MD5: Plaintext password not "
"configured");
data->state = FAILURE;
return;
}
pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &plen);
if (pos == NULL || *pos != CHAP_MD5_LEN || plen < 1 + CHAP_MD5_LEN)
return; /* Should not happen - frame already validated */
pos++; /* Skip response len */
wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Response", pos, CHAP_MD5_LEN);
id = eap_get_id(respData);
if (chap_md5(id, sm->user->password, sm->user->password_len,
data->challenge, CHALLENGE_LEN, hash)) {
wpa_printf(MSG_INFO, "EAP-MD5: CHAP MD5 operation failed");
data->state = FAILURE;
return;
}
if (os_memcmp(hash, pos, CHAP_MD5_LEN) == 0) {
wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Success");
data->state = SUCCESS;
} else {
wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Failure");
data->state = FAILURE;
}
}
static Boolean eap_md5_isDone(struct eap_sm *sm, void *priv)
{
struct eap_md5_data *data = priv;
return data->state != CONTINUE;
}
static Boolean eap_md5_isSuccess(struct eap_sm *sm, void *priv)
{
struct eap_md5_data *data = priv;
return data->state == SUCCESS;
}
int eap_server_md5_register(void)
{
struct eap_method *eap;
int ret;
eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
EAP_VENDOR_IETF, EAP_TYPE_MD5, "MD5");
if (eap == NULL)
return -1;
eap->init = eap_md5_init;
eap->reset = eap_md5_reset;
eap->buildReq = eap_md5_buildReq;
eap->check = eap_md5_check;
eap->process = eap_md5_process;
eap->isDone = eap_md5_isDone;
eap->isSuccess = eap_md5_isSuccess;
ret = eap_server_method_register(eap);
if (ret)
eap_server_method_free(eap);
return ret;
}