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      1 /*
      2  * EAP peer method: EAP-GTC (RFC 3748)
      3  * Copyright (c) 2004-2006, 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 
     20 
     21 struct eap_gtc_data {
     22 	int prefix;
     23 };
     24 
     25 
     26 static void * eap_gtc_init(struct eap_sm *sm)
     27 {
     28 	struct eap_gtc_data *data;
     29 	data = os_zalloc(sizeof(*data));
     30 	if (data == NULL)
     31 		return NULL;
     32 
     33 	if (sm->m && sm->m->vendor == EAP_VENDOR_IETF &&
     34 	    sm->m->method == EAP_TYPE_FAST) {
     35 		wpa_printf(MSG_DEBUG, "EAP-GTC: EAP-FAST tunnel - use prefix "
     36 			   "with challenge/response");
     37 		data->prefix = 1;
     38 	}
     39 	return data;
     40 }
     41 
     42 
     43 static void eap_gtc_deinit(struct eap_sm *sm, void *priv)
     44 {
     45 	struct eap_gtc_data *data = priv;
     46 	os_free(data);
     47 }
     48 
     49 
     50 static struct wpabuf * eap_gtc_process(struct eap_sm *sm, void *priv,
     51 				       struct eap_method_ret *ret,
     52 				       const struct wpabuf *reqData)
     53 {
     54 	struct eap_gtc_data *data = priv;
     55 	struct wpabuf *resp;
     56 	const u8 *pos, *password, *identity;
     57 	size_t password_len, identity_len, len, plen;
     58 	int otp;
     59 	u8 id;
     60 
     61 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_GTC, reqData, &len);
     62 	if (pos == NULL) {
     63 		ret->ignore = TRUE;
     64 		return NULL;
     65 	}
     66 	id = eap_get_id(reqData);
     67 
     68 	wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-GTC: Request message", pos, len);
     69 	if (data->prefix &&
     70 	    (len < 10 || os_memcmp(pos, "CHALLENGE=", 10) != 0)) {
     71 		wpa_printf(MSG_DEBUG, "EAP-GTC: Challenge did not start with "
     72 			   "expected prefix");
     73 
     74 		/* Send an empty response in order to allow tunneled
     75 		 * acknowledgement of the failure. This will also cover the
     76 		 * error case which seems to use EAP-MSCHAPv2 like error
     77 		 * reporting with EAP-GTC inside EAP-FAST tunnel. */
     78 		resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC,
     79 				     0, EAP_CODE_RESPONSE, id);
     80 		return resp;
     81 	}
     82 
     83 	password = eap_get_config_otp(sm, &password_len);
     84 	if (password)
     85 		otp = 1;
     86 	else {
     87 		password = eap_get_config_password(sm, &password_len);
     88 		otp = 0;
     89 	}
     90 
     91 	if (password == NULL) {
     92 		wpa_printf(MSG_INFO, "EAP-GTC: Password not configured");
     93 		eap_sm_request_otp(sm, (const char *) pos, len);
     94 		ret->ignore = TRUE;
     95 		return NULL;
     96 	}
     97 
     98 	ret->ignore = FALSE;
     99 
    100 	ret->methodState = data->prefix ? METHOD_MAY_CONT : METHOD_DONE;
    101 	ret->decision = DECISION_COND_SUCC;
    102 	ret->allowNotifications = FALSE;
    103 
    104 	plen = password_len;
    105 	identity = eap_get_config_identity(sm, &identity_len);
    106 	if (identity == NULL)
    107 		return NULL;
    108 	if (data->prefix)
    109 		plen += 9 + identity_len + 1;
    110 	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC, plen,
    111 			     EAP_CODE_RESPONSE, id);
    112 	if (resp == NULL)
    113 		return NULL;
    114 	if (data->prefix) {
    115 		wpabuf_put_data(resp, "RESPONSE=", 9);
    116 		wpabuf_put_data(resp, identity, identity_len);
    117 		wpabuf_put_u8(resp, '\0');
    118 	}
    119 	wpabuf_put_data(resp, password, password_len);
    120 	wpa_hexdump_ascii_key(MSG_MSGDUMP, "EAP-GTC: Response",
    121 			      wpabuf_head_u8(resp) + sizeof(struct eap_hdr) +
    122 			      1, plen);
    123 
    124 	if (otp) {
    125 		wpa_printf(MSG_DEBUG, "EAP-GTC: Forgetting used password");
    126 		eap_clear_config_otp(sm);
    127 	}
    128 
    129 	return resp;
    130 }
    131 
    132 
    133 int eap_peer_gtc_register(void)
    134 {
    135 	struct eap_method *eap;
    136 	int ret;
    137 
    138 	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
    139 				    EAP_VENDOR_IETF, EAP_TYPE_GTC, "GTC");
    140 	if (eap == NULL)
    141 		return -1;
    142 
    143 	eap->init = eap_gtc_init;
    144 	eap->deinit = eap_gtc_deinit;
    145 	eap->process = eap_gtc_process;
    146 
    147 	ret = eap_peer_method_register(eap);
    148 	if (ret)
    149 		eap_peer_method_free(eap);
    150 	return ret;
    151 }
    152