eap_ttls.c

一个Linux下无线网卡的设置工具

/*
 * WPA Supplicant / EAP-TTLS (draft-ietf-pppext-eap-ttls-03.txt)
 * Copyright (c) 2004-2005, Jouni Malinen <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "common.h"
#include "eap_i.h"
#include "eap_tls_common.h"
#include "wpa_supplicant.h"
#include "config_ssid.h"
#include "ms_funcs.h"
#include "crypto.h"
#include "tls.h"
#include "eap_ttls.h"


static void eap_ttls_deinit(struct eap_sm *sm, void *priv);


struct eap_ttls_data {
	struct eap_ssl_data ssl;

	const struct eap_method *phase2_method;
	void *phase2_priv;
	int phase2_success;
	int phase2_start;

	enum {
		EAP_TTLS_PHASE2_EAP,
		EAP_TTLS_PHASE2_MSCHAPV2,
		EAP_TTLS_PHASE2_MSCHAP,
		EAP_TTLS_PHASE2_PAP,
		EAP_TTLS_PHASE2_CHAP
	} phase2_type;
	u8 phase2_eap_type;
	u8 *phase2_eap_types;
	size_t num_phase2_eap_types;

	u8 auth_response[20];
	int auth_response_valid;
	u8 ident;
	int resuming; /* starting a resumed session */
	int reauth; /* reauthentication */
	u8 *key_data;

	u8 *pending_phase2_req;
	size_t pending_phase2_req_len;
};


static void * eap_ttls_init(struct eap_sm *sm)
{
	struct eap_ttls_data *data;
	struct wpa_ssid *config = eap_get_config(sm);
	char *selected;

	data = malloc(sizeof(*data));
	if (data == NULL)
		return NULL;
	memset(data, 0, sizeof(*data));
	selected = "EAP";
	data->phase2_type = EAP_TTLS_PHASE2_EAP;
	if (config && config->phase2) {
		if (strstr(config->phase2, "autheap=")) {
			selected = "EAP";
			data->phase2_type = EAP_TTLS_PHASE2_EAP;
		} else if (strstr(config->phase2, "auth=MSCHAPV2")) {
			selected = "MSCHAPV2";
			data->phase2_type = EAP_TTLS_PHASE2_MSCHAPV2;
		} else if (strstr(config->phase2, "auth=MSCHAP")) {
			selected = "MSCHAP";
			data->phase2_type = EAP_TTLS_PHASE2_MSCHAP;
		} else if (strstr(config->phase2, "auth=PAP")) {
			selected = "PAP";
			data->phase2_type = EAP_TTLS_PHASE2_PAP;
		} else if (strstr(config->phase2, "auth=CHAP")) {
			selected = "CHAP";
			data->phase2_type = EAP_TTLS_PHASE2_CHAP;
		}
	}
	wpa_printf(MSG_DEBUG, "EAP-TTLS: Phase2 type: %s", selected);

	if (data->phase2_type == EAP_TTLS_PHASE2_EAP) {
		if (config && config->phase2) {
			char *start, *pos, *buf;
			u8 method, *methods = NULL, *_methods;
			size_t num_methods = 0;
			start = buf = strdup(config->phase2);
			if (buf == NULL) {
				eap_ttls_deinit(sm, data);
				return NULL;
			}
			while (start && *start != '\0') {
				pos = strstr(start, "autheap=");
				if (pos == NULL)
					break;
				if (start != pos && *(pos - 1) != ' ') {
					start = pos + 8;
					continue;
				}

				start = pos + 8;
				pos = strchr(start, ' ');
				if (pos)
					*pos++ = '\0';
				method = eap_get_phase2_type(start);
				if (method == EAP_TYPE_NONE) {
					wpa_printf(MSG_ERROR, "EAP-TTLS: "
						   "Unsupported Phase2 EAP "
						   "method '%s'", start);
				} else {
					num_methods++;
					_methods = realloc(methods,
							   num_methods);
					if (_methods == NULL) {
						free(methods);
						free(buf);
						eap_ttls_deinit(sm, data);
						return NULL;
					}
					methods = _methods;
					methods[num_methods - 1] = method;
				}

				start = pos;
			}
			free(buf);
			data->phase2_eap_types = methods;
			data->num_phase2_eap_types = num_methods;
		}
		if (data->phase2_eap_types == NULL) {
			data->phase2_eap_types = eap_get_phase2_types(
				config, &data->num_phase2_eap_types);
		}
		if (data->phase2_eap_types == NULL) {
			wpa_printf(MSG_ERROR, "EAP-TTLS: No Phase2 EAP method "
				   "available");
			eap_ttls_deinit(sm, data);
			return NULL;
		}
		wpa_hexdump(MSG_DEBUG, "EAP-TTLS: Phase2 EAP types",
			    data->phase2_eap_types,
			    data->num_phase2_eap_types);
		data->phase2_eap_type = EAP_TYPE_NONE;
	}


	if (eap_tls_ssl_init(sm, &data->ssl, config)) {
		wpa_printf(MSG_INFO, "EAP-TTLS: Failed to initialize SSL.");
		eap_ttls_deinit(sm, data);
		return NULL;
	}

	return data;
}


static void eap_ttls_deinit(struct eap_sm *sm, void *priv)
{
	struct eap_ttls_data *data = priv;
	if (data == NULL)
		return;
	if (data->phase2_priv && data->phase2_method)
		data->phase2_method->deinit(sm, data->phase2_priv);
	free(data->phase2_eap_types);
	eap_tls_ssl_deinit(sm, &data->ssl);
	free(data->key_data);
	free(data->pending_phase2_req);
	free(data);
}


static int eap_ttls_encrypt(struct eap_sm *sm, struct eap_ttls_data *data,
			    int id, const u8 *plain, size_t plain_len,
			    u8 **out_data, size_t *out_len)
{
	int res;
	u8 *pos;
	struct eap_hdr *resp;

	/* TODO: add support for fragmentation, if needed. This will need to
	 * add TLS Message Length field, if the frame is fragmented. */
	resp = malloc(sizeof(struct eap_hdr) + 2 + data->ssl.tls_out_limit);
	if (resp == NULL)
		return -1;

	resp->code = EAP_CODE_RESPONSE;
	resp->identifier = id;

	pos = (u8 *) (resp + 1);
	*pos++ = EAP_TYPE_TTLS;
	*pos++ = 0;

	res = tls_connection_encrypt(sm->ssl_ctx, data->ssl.conn,
				     plain, plain_len,
				     pos, data->ssl.tls_out_limit);
	if (res < 0) {
		wpa_printf(MSG_INFO, "EAP-TTLS: Failed to encrypt Phase 2 "
			   "data");
		free(resp);
		return -1;
	}

	*out_len = sizeof(struct eap_hdr) + 2 + res;
	resp->length = host_to_be16(*out_len);
	*out_data = (u8 *) resp;
	return 0;
}


static u8 * eap_ttls_avp_hdr(u8 *avphdr, u32 avp_code, u32 vendor_id,
			     int mandatory, size_t len)
{
	struct ttls_avp_vendor *avp;
	u8 flags;
	size_t hdrlen;

	avp = (struct ttls_avp_vendor *) avphdr;
	flags = mandatory ? AVP_FLAGS_MANDATORY : 0;
	if (vendor_id) {
		flags |= AVP_FLAGS_VENDOR;
		hdrlen = sizeof(*avp);
		avp->vendor_id = host_to_be32(vendor_id);
	} else {
		hdrlen = sizeof(struct ttls_avp);
	}

	avp->avp_code = host_to_be32(avp_code);
	avp->avp_length = host_to_be32((flags << 24) | (hdrlen + len));

	return avphdr + hdrlen;
}


static u8 * eap_ttls_avp_add(u8 *start, u8 *avphdr, u32 avp_code,
			     u32 vendor_id, int mandatory,
			     u8 *data, size_t len)
{
	u8 *pos;
	pos = eap_ttls_avp_hdr(avphdr, avp_code, vendor_id, mandatory, len);
	memcpy(pos, data, len);
	pos += len;
	AVP_PAD(start, pos);
	return pos;
}


static int eap_ttls_avp_encapsulate(u8 **resp, size_t *resp_len, u32 avp_code,
				    int mandatory)
{
	u8 *avp, *pos;

	avp = malloc(sizeof(struct ttls_avp) + *resp_len + 4);
	if (avp == NULL) {
		free(*resp);
		*resp = NULL;
		*resp_len = 0;
		return -1;
	}

	pos = eap_ttls_avp_hdr(avp, avp_code, 0, mandatory, *resp_len);
	memcpy(pos, *resp, *resp_len);
	pos += *resp_len;
	AVP_PAD(avp, pos);
	free(*resp);
	*resp = avp;
	*resp_len = pos - avp;
	return 0;
}


static int eap_ttls_phase2_nak(struct eap_sm *sm,
			       struct eap_ttls_data *data,
			       struct eap_hdr *hdr,
			       u8 **resp, size_t *resp_len)
{
	struct eap_hdr *resp_hdr;
	u8 *pos = (u8 *) (hdr + 1);

	wpa_printf(MSG_DEBUG, "EAP-TTLS: Phase 2 Request: Nak type=%d", *pos);
	wpa_hexdump(MSG_DEBUG, "EAP-TTLS: Allowed Phase2 EAP types",
		    data->phase2_eap_types, data->num_phase2_eap_types);
	*resp_len = sizeof(struct eap_hdr) + 1 + data->num_phase2_eap_types;
	*resp = malloc(*resp_len);
	if (*resp == NULL)
		return -1;

	resp_hdr = (struct eap_hdr *) (*resp);
	resp_hdr->code = EAP_CODE_RESPONSE;
	resp_hdr->identifier = hdr->identifier;
	resp_hdr->length = host_to_be16(*resp_len);
	pos = (u8 *) (resp_hdr + 1);
	*pos++ = EAP_TYPE_NAK;
	memcpy(pos, data->phase2_eap_types, data->num_phase2_eap_types);

	return 0;
}


static int eap_ttls_phase2_request_eap(struct eap_sm *sm,
				       struct eap_ttls_data *data,
				       struct eap_method_ret *ret,
				       const struct eap_hdr *req,
				       struct eap_hdr *hdr,
				       u8 **resp, size_t *resp_len)
{
	size_t len = be_to_host16(hdr->length);
	u8 *pos;
	struct eap_method_ret iret;
	struct wpa_ssid *config = eap_get_config(sm);

	if (len <= sizeof(struct eap_hdr)) {
		wpa_printf(MSG_INFO, "EAP-TTLS: too short "
			   "Phase 2 request (len=%lu)", (unsigned long) len);
		return -1;
	}
	pos = (u8 *) (hdr + 1);
	wpa_printf(MSG_DEBUG, "EAP-TTLS: Phase 2 EAP Request: type=%d", *pos);
	switch (*pos) {
	case EAP_TYPE_IDENTITY:
		*resp = eap_sm_buildIdentity(sm, req->identifier, resp_len, 1);
		break;
	default:
		if (data->phase2_eap_type == EAP_TYPE_NONE) {
			int i;
			for (i = 0; i < data->num_phase2_eap_types; i++) {
				if (data->phase2_eap_types[i] != *pos)
					continue;

				data->phase2_eap_type = *pos;
				wpa_printf(MSG_DEBUG, "EAP-TTLS: Selected "
					   "Phase 2 EAP method %d",
					   data->phase2_eap_type);
				break;
			}
		}
		if (*pos != data->phase2_eap_type || *pos == EAP_TYPE_NONE) {
			if (eap_ttls_phase2_nak(sm, data, hdr, resp, resp_len))
				return -1;
			break;
		}

		if (data->phase2_priv == NULL) {
			data->phase2_method = eap_sm_get_eap_methods(*pos);
			if (data->phase2_method) {
				sm->init_phase2 = 1;
				data->phase2_priv =
					data->phase2_method->init(sm);
				sm->init_phase2 = 0;
			}
		}
		if (data->phase2_priv == NULL || data->phase2_method == NULL) {
			wpa_printf(MSG_INFO, "EAP-TTLS: failed to initialize "
				   "Phase 2 EAP method %d", *pos);
			return -1;
		}
		memset(&iret, 0, sizeof(iret));
		*resp = data->phase2_method->process(sm, data->phase2_priv,
						     &iret, (u8 *) hdr, len,
						     resp_len);
		if ((iret.methodState == METHOD_DONE ||
		     iret.methodState == METHOD_MAY_CONT) &&
		    (iret.decision == DECISION_UNCOND_SUCC ||
		     iret.decision == DECISION_COND_SUCC ||
		     iret.decision == DECISION_FAIL)) {
			ret->methodState = iret.methodState;
			ret->decision = iret.decision;
		}
		break;
	}

	if (*resp == NULL &&
	    (config->pending_req_identity || config->pending_req_password ||
	     config->pending_req_otp)) {
		return 0;
	}

	if (*resp == NULL)
		return -1;

	wpa_hexdump(MSG_DEBUG, "EAP-TTLS: AVP encapsulate EAP Response",
		    *resp, *resp_len);
	return eap_ttls_avp_encapsulate(resp, resp_len,
					RADIUS_ATTR_EAP_MESSAGE, 1);
}


static int eap_ttls_phase2_request_mschapv2(struct eap_sm *sm,
					    struct eap_ttls_data *data,
					    struct eap_method_ret *ret,
					    const struct eap_hdr *req,
					    struct eap_hdr *hdr,
					    u8 **resp, size_t *resp_len)
{
	struct wpa_ssid *config = eap_get_config(sm);
	u8 *buf, *pos, *challenge, *username, *peer_challenge;
	size_t username_len;
	int i;

	wpa_printf(MSG_DEBUG, "EAP-TTLS: Phase 2 MSCHAPV2 Request");

	/* MSCHAPv2 does not include optional domain name in the
	 * challenge-response calculation, so remove domain prefix
	 * (if present). */
	username = config->identity;
	username_len = config->identity_len;
	pos = username;
	for (i = 0; i < username_len; i++) {
		if (username[i] == '\\') {
			username_len -= i + 1;
			username += i + 1;
			break;
		}
	}

	pos = buf = malloc(config->identity_len + 1000);
	if (buf == NULL) {
		wpa_printf(MSG_ERROR,
			   "EAP-TTLS/MSCHAPV2: Failed to allocate memory");
		return -1;
	}

	/* User-Name */
	pos = eap_ttls_avp_add(buf, pos, RADIUS_ATTR_USER_NAME, 0, 1,
			       config->identity, config->identity_len);

	/* MS-CHAP-Challenge */
	challenge = eap_tls_derive_key(sm, &data->ssl, "ttls challenge",
				       EAP_TTLS_MSCHAPV2_CHALLENGE_LEN * 2 +
				       1);
	if (challenge == NULL) {
		free(buf);
		wpa_printf(MSG_ERROR, "EAP-TTLS/MSCHAPV2: Failed to derive "
			   "implicit challenge");
		return -1;
	}
	peer_challenge = challenge + 1 + EAP_TTLS_MSCHAPV2_CHALLENGE_LEN;

	pos = eap_ttls_avp_add(buf, pos, RADIUS_ATTR_MS_CHAP_CHALLENGE,
			       RADIUS_VENDOR_ID_MICROSOFT, 1,
			       challenge, EAP_TTLS_MSCHAPV2_CHALLENGE_LEN);