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      1 /*
      2  * hostapd / EAP-MD5 server
      3  * Copyright (c) 2004-2012, Jouni Malinen <j (at) w1.fi>
      4  *
      5  * This software may be distributed under the terms of the BSD license.
      6  * See README for more details.
      7  */
      8 
      9 #include "includes.h"
     10 
     11 #include "common.h"
     12 #include "crypto/random.h"
     13 #include "eap_i.h"
     14 #include "eap_common/chap.h"
     15 
     16 
     17 #define CHALLENGE_LEN 16
     18 
     19 struct eap_md5_data {
     20 	u8 challenge[CHALLENGE_LEN];
     21 	enum { CONTINUE, SUCCESS, FAILURE } state;
     22 };
     23 
     24 
     25 static void * eap_md5_init(struct eap_sm *sm)
     26 {
     27 	struct eap_md5_data *data;
     28 
     29 	data = os_zalloc(sizeof(*data));
     30 	if (data == NULL)
     31 		return NULL;
     32 	data->state = CONTINUE;
     33 
     34 	return data;
     35 }
     36 
     37 
     38 static void eap_md5_reset(struct eap_sm *sm, void *priv)
     39 {
     40 	struct eap_md5_data *data = priv;
     41 	os_free(data);
     42 }
     43 
     44 
     45 static struct wpabuf * eap_md5_buildReq(struct eap_sm *sm, void *priv, u8 id)
     46 {
     47 	struct eap_md5_data *data = priv;
     48 	struct wpabuf *req;
     49 
     50 	if (random_get_bytes(data->challenge, CHALLENGE_LEN)) {
     51 		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to get random data");
     52 		data->state = FAILURE;
     53 		return NULL;
     54 	}
     55 
     56 	req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MD5, 1 + CHALLENGE_LEN,
     57 			    EAP_CODE_REQUEST, id);
     58 	if (req == NULL) {
     59 		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to allocate memory for "
     60 			   "request");
     61 		data->state = FAILURE;
     62 		return NULL;
     63 	}
     64 
     65 	wpabuf_put_u8(req, CHALLENGE_LEN);
     66 	wpabuf_put_data(req, data->challenge, CHALLENGE_LEN);
     67 	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Challenge", data->challenge,
     68 		    CHALLENGE_LEN);
     69 
     70 	data->state = CONTINUE;
     71 
     72 	return req;
     73 }
     74 
     75 
     76 static Boolean eap_md5_check(struct eap_sm *sm, void *priv,
     77 			     struct wpabuf *respData)
     78 {
     79 	const u8 *pos;
     80 	size_t len;
     81 
     82 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &len);
     83 	if (pos == NULL || len < 1) {
     84 		wpa_printf(MSG_INFO, "EAP-MD5: Invalid frame");
     85 		return TRUE;
     86 	}
     87 	if (*pos != CHAP_MD5_LEN || 1 + CHAP_MD5_LEN > len) {
     88 		wpa_printf(MSG_INFO, "EAP-MD5: Invalid response "
     89 			   "(response_len=%d payload_len=%lu",
     90 			   *pos, (unsigned long) len);
     91 		return TRUE;
     92 	}
     93 
     94 	return FALSE;
     95 }
     96 
     97 
     98 static void eap_md5_process(struct eap_sm *sm, void *priv,
     99 			    struct wpabuf *respData)
    100 {
    101 	struct eap_md5_data *data = priv;
    102 	const u8 *pos;
    103 	size_t plen;
    104 	u8 hash[CHAP_MD5_LEN], id;
    105 
    106 	if (sm->user == NULL || sm->user->password == NULL ||
    107 	    sm->user->password_hash) {
    108 		wpa_printf(MSG_INFO, "EAP-MD5: Plaintext password not "
    109 			   "configured");
    110 		data->state = FAILURE;
    111 		return;
    112 	}
    113 
    114 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &plen);
    115 	if (pos == NULL || *pos != CHAP_MD5_LEN || plen < 1 + CHAP_MD5_LEN)
    116 		return; /* Should not happen - frame already validated */
    117 
    118 	pos++; /* Skip response len */
    119 	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Response", pos, CHAP_MD5_LEN);
    120 
    121 	id = eap_get_id(respData);
    122 	if (chap_md5(id, sm->user->password, sm->user->password_len,
    123 		     data->challenge, CHALLENGE_LEN, hash)) {
    124 		wpa_printf(MSG_INFO, "EAP-MD5: CHAP MD5 operation failed");
    125 		data->state = FAILURE;
    126 		return;
    127 	}
    128 
    129 	if (os_memcmp_const(hash, pos, CHAP_MD5_LEN) == 0) {
    130 		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Success");
    131 		data->state = SUCCESS;
    132 	} else {
    133 		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Failure");
    134 		data->state = FAILURE;
    135 	}
    136 }
    137 
    138 
    139 static Boolean eap_md5_isDone(struct eap_sm *sm, void *priv)
    140 {
    141 	struct eap_md5_data *data = priv;
    142 	return data->state != CONTINUE;
    143 }
    144 
    145 
    146 static Boolean eap_md5_isSuccess(struct eap_sm *sm, void *priv)
    147 {
    148 	struct eap_md5_data *data = priv;
    149 	return data->state == SUCCESS;
    150 }
    151 
    152 
    153 int eap_server_md5_register(void)
    154 {
    155 	struct eap_method *eap;
    156 
    157 	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
    158 				      EAP_VENDOR_IETF, EAP_TYPE_MD5, "MD5");
    159 	if (eap == NULL)
    160 		return -1;
    161 
    162 	eap->init = eap_md5_init;
    163 	eap->reset = eap_md5_reset;
    164 	eap->buildReq = eap_md5_buildReq;
    165 	eap->check = eap_md5_check;
    166 	eap->process = eap_md5_process;
    167 	eap->isDone = eap_md5_isDone;
    168 	eap->isSuccess = eap_md5_isSuccess;
    169 
    170 	return eap_server_method_register(eap);
    171 }
    172