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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 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 "eap_i.h"
     13 
     14 
     15 struct eap_gtc_data {
     16 	int prefix;
     17 };
     18 
     19 
     20 static void * eap_gtc_init(struct eap_sm *sm)
     21 {
     22 	struct eap_gtc_data *data;
     23 	data = os_zalloc(sizeof(*data));
     24 	if (data == NULL)
     25 		return NULL;
     26 
     27 	if (sm->m && sm->m->vendor == EAP_VENDOR_IETF &&
     28 	    sm->m->method == EAP_TYPE_FAST) {
     29 		wpa_printf(MSG_DEBUG, "EAP-GTC: EAP-FAST tunnel - use prefix "
     30 			   "with challenge/response");
     31 		data->prefix = 1;
     32 	}
     33 	return data;
     34 }
     35 
     36 
     37 static void eap_gtc_deinit(struct eap_sm *sm, void *priv)
     38 {
     39 	struct eap_gtc_data *data = priv;
     40 	os_free(data);
     41 }
     42 
     43 
     44 static struct wpabuf * eap_gtc_process(struct eap_sm *sm, void *priv,
     45 				       struct eap_method_ret *ret,
     46 				       const struct wpabuf *reqData)
     47 {
     48 	struct eap_gtc_data *data = priv;
     49 	struct wpabuf *resp;
     50 	const u8 *pos, *password, *identity;
     51 	size_t password_len, identity_len, len, plen;
     52 	int otp;
     53 	u8 id;
     54 
     55 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_GTC, reqData, &len);
     56 	if (pos == NULL) {
     57 		ret->ignore = TRUE;
     58 		return NULL;
     59 	}
     60 	id = eap_get_id(reqData);
     61 
     62 	wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-GTC: Request message", pos, len);
     63 	if (data->prefix &&
     64 	    (len < 10 || os_memcmp(pos, "CHALLENGE=", 10) != 0)) {
     65 		wpa_printf(MSG_DEBUG, "EAP-GTC: Challenge did not start with "
     66 			   "expected prefix");
     67 
     68 		/* Send an empty response in order to allow tunneled
     69 		 * acknowledgement of the failure. This will also cover the
     70 		 * error case which seems to use EAP-MSCHAPv2 like error
     71 		 * reporting with EAP-GTC inside EAP-FAST tunnel. */
     72 		resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC,
     73 				     0, EAP_CODE_RESPONSE, id);
     74 		return resp;
     75 	}
     76 
     77 	password = eap_get_config_otp(sm, &password_len);
     78 	if (password)
     79 		otp = 1;
     80 	else {
     81 		password = eap_get_config_password(sm, &password_len);
     82 		otp = 0;
     83 	}
     84 
     85 	if (password == NULL) {
     86 		wpa_printf(MSG_INFO, "EAP-GTC: Password not configured");
     87 		eap_sm_request_otp(sm, (const char *) pos, len);
     88 		ret->ignore = TRUE;
     89 		return NULL;
     90 	}
     91 
     92 	ret->ignore = FALSE;
     93 
     94 	ret->methodState = data->prefix ? METHOD_MAY_CONT : METHOD_DONE;
     95 	ret->decision = DECISION_COND_SUCC;
     96 	ret->allowNotifications = FALSE;
     97 
     98 	plen = password_len;
     99 	identity = eap_get_config_identity(sm, &identity_len);
    100 	if (identity == NULL)
    101 		return NULL;
    102 	if (data->prefix)
    103 		plen += 9 + identity_len + 1;
    104 	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_GTC, plen,
    105 			     EAP_CODE_RESPONSE, id);
    106 	if (resp == NULL)
    107 		return NULL;
    108 	if (data->prefix) {
    109 		wpabuf_put_data(resp, "RESPONSE=", 9);
    110 		wpabuf_put_data(resp, identity, identity_len);
    111 		wpabuf_put_u8(resp, '\0');
    112 	}
    113 	wpabuf_put_data(resp, password, password_len);
    114 	wpa_hexdump_ascii_key(MSG_MSGDUMP, "EAP-GTC: Response",
    115 			      wpabuf_head_u8(resp) + sizeof(struct eap_hdr) +
    116 			      1, plen);
    117 
    118 	if (otp) {
    119 		wpa_printf(MSG_DEBUG, "EAP-GTC: Forgetting used password");
    120 		eap_clear_config_otp(sm);
    121 	}
    122 
    123 	return resp;
    124 }
    125 
    126 
    127 int eap_peer_gtc_register(void)
    128 {
    129 	struct eap_method *eap;
    130 
    131 	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
    132 				    EAP_VENDOR_IETF, EAP_TYPE_GTC, "GTC");
    133 	if (eap == NULL)
    134 		return -1;
    135 
    136 	eap->init = eap_gtc_init;
    137 	eap->deinit = eap_gtc_deinit;
    138 	eap->process = eap_gtc_process;
    139 
    140 	return eap_peer_method_register(eap);
    141 }
    142