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      1 /*
      2  * hostapd / EAP-MD5 server
      3  * Copyright (c) 2004-2007, Jouni Malinen <j (at) w1.fi>
      4  *
      5  * This program is free software; you can redistribute it and/or modify
      6  * it under the terms of the GNU General Public License version 2 as
      7  * published by the Free Software Foundation.
      8  *
      9  * Alternatively, this software may be distributed under the terms of BSD
     10  * license.
     11  *
     12  * See README and COPYING for more details.
     13  */
     14 
     15 #include "includes.h"
     16 
     17 #include "common.h"
     18 #include "crypto/random.h"
     19 #include "eap_i.h"
     20 #include "eap_common/chap.h"
     21 
     22 
     23 #define CHALLENGE_LEN 16
     24 
     25 struct eap_md5_data {
     26 	u8 challenge[CHALLENGE_LEN];
     27 	enum { CONTINUE, SUCCESS, FAILURE } state;
     28 };
     29 
     30 
     31 static void * eap_md5_init(struct eap_sm *sm)
     32 {
     33 	struct eap_md5_data *data;
     34 
     35 	data = os_zalloc(sizeof(*data));
     36 	if (data == NULL)
     37 		return NULL;
     38 	data->state = CONTINUE;
     39 
     40 	return data;
     41 }
     42 
     43 
     44 static void eap_md5_reset(struct eap_sm *sm, void *priv)
     45 {
     46 	struct eap_md5_data *data = priv;
     47 	os_free(data);
     48 }
     49 
     50 
     51 static struct wpabuf * eap_md5_buildReq(struct eap_sm *sm, void *priv, u8 id)
     52 {
     53 	struct eap_md5_data *data = priv;
     54 	struct wpabuf *req;
     55 
     56 	if (random_get_bytes(data->challenge, CHALLENGE_LEN)) {
     57 		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to get random data");
     58 		data->state = FAILURE;
     59 		return NULL;
     60 	}
     61 
     62 	req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MD5, 1 + CHALLENGE_LEN,
     63 			    EAP_CODE_REQUEST, id);
     64 	if (req == NULL) {
     65 		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to allocate memory for "
     66 			   "request");
     67 		data->state = FAILURE;
     68 		return NULL;
     69 	}
     70 
     71 	wpabuf_put_u8(req, CHALLENGE_LEN);
     72 	wpabuf_put_data(req, data->challenge, CHALLENGE_LEN);
     73 	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Challenge", data->challenge,
     74 		    CHALLENGE_LEN);
     75 
     76 	data->state = CONTINUE;
     77 
     78 	return req;
     79 }
     80 
     81 
     82 static Boolean eap_md5_check(struct eap_sm *sm, void *priv,
     83 			     struct wpabuf *respData)
     84 {
     85 	const u8 *pos;
     86 	size_t len;
     87 
     88 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &len);
     89 	if (pos == NULL || len < 1) {
     90 		wpa_printf(MSG_INFO, "EAP-MD5: Invalid frame");
     91 		return TRUE;
     92 	}
     93 	if (*pos != CHAP_MD5_LEN || 1 + CHAP_MD5_LEN > len) {
     94 		wpa_printf(MSG_INFO, "EAP-MD5: Invalid response "
     95 			   "(response_len=%d payload_len=%lu",
     96 			   *pos, (unsigned long) len);
     97 		return TRUE;
     98 	}
     99 
    100 	return FALSE;
    101 }
    102 
    103 
    104 static void eap_md5_process(struct eap_sm *sm, void *priv,
    105 			    struct wpabuf *respData)
    106 {
    107 	struct eap_md5_data *data = priv;
    108 	const u8 *pos;
    109 	size_t plen;
    110 	u8 hash[CHAP_MD5_LEN], id;
    111 
    112 	if (sm->user == NULL || sm->user->password == NULL ||
    113 	    sm->user->password_hash) {
    114 		wpa_printf(MSG_INFO, "EAP-MD5: Plaintext password not "
    115 			   "configured");
    116 		data->state = FAILURE;
    117 		return;
    118 	}
    119 
    120 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &plen);
    121 	if (pos == NULL || *pos != CHAP_MD5_LEN || plen < 1 + CHAP_MD5_LEN)
    122 		return; /* Should not happen - frame already validated */
    123 
    124 	pos++; /* Skip response len */
    125 	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Response", pos, CHAP_MD5_LEN);
    126 
    127 	id = eap_get_id(respData);
    128 	chap_md5(id, sm->user->password, sm->user->password_len,
    129 		 data->challenge, CHALLENGE_LEN, hash);
    130 
    131 	if (os_memcmp(hash, pos, CHAP_MD5_LEN) == 0) {
    132 		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Success");
    133 		data->state = SUCCESS;
    134 	} else {
    135 		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Failure");
    136 		data->state = FAILURE;
    137 	}
    138 }
    139 
    140 
    141 static Boolean eap_md5_isDone(struct eap_sm *sm, void *priv)
    142 {
    143 	struct eap_md5_data *data = priv;
    144 	return data->state != CONTINUE;
    145 }
    146 
    147 
    148 static Boolean eap_md5_isSuccess(struct eap_sm *sm, void *priv)
    149 {
    150 	struct eap_md5_data *data = priv;
    151 	return data->state == SUCCESS;
    152 }
    153 
    154 
    155 int eap_server_md5_register(void)
    156 {
    157 	struct eap_method *eap;
    158 	int ret;
    159 
    160 	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
    161 				      EAP_VENDOR_IETF, EAP_TYPE_MD5, "MD5");
    162 	if (eap == NULL)
    163 		return -1;
    164 
    165 	eap->init = eap_md5_init;
    166 	eap->reset = eap_md5_reset;
    167 	eap->buildReq = eap_md5_buildReq;
    168 	eap->check = eap_md5_check;
    169 	eap->process = eap_md5_process;
    170 	eap->isDone = eap_md5_isDone;
    171 	eap->isSuccess = eap_md5_isSuccess;
    172 
    173 	ret = eap_server_method_register(eap);
    174 	if (ret)
    175 		eap_server_method_free(eap);
    176 	return ret;
    177 }
    178