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