eap: Add initial EAP API

Adds eap.c/eap.h with the initial EAP API definitions.  No actual EAP
methods are added in this patch.

Makefile.am

@@ -69,6 +69,7 @@ src_iwd_SOURCES = src/main.c linux/nl80211.h linux/kdbus.h \
 					src/network.h src/network.c \
 					src/wscutil.h src/wscutil.c \
 					src/wsc.h src/wsc.c \
+					src/eap.h src/eap.c \
 					src/iwd.h
 src_iwd_LDADD = ell/libell-internal.la
 
@@ -86,7 +87,8 @@ monitor_iwmon_SOURCES = monitor/main.c linux/nl80211.h \
 					src/util.h src/util.c \
 					src/sha1.h src/sha1.c \
 					src/crypto.h src/crypto.c \
-					src/eapol.h src/eapol.c
+					src/eapol.h src/eapol.c \
+					src/eap.h src/eap.c
 monitor_iwmon_LDADD = ell/libell-internal.la
 
 noinst_PROGRAMS = tools/hwsim
@@ -153,7 +155,8 @@ unit_test_eapol_SOURCES = unit/test-eapol.c \
 				src/sha1.h src/sha1.c \
 				src/crypto.h src/crypto.c \
 				src/ie.h src/ie.c \
-				src/eapol.h src/eapol.c
+				src/eapol.h src/eapol.c \
+				src/eap.h src/eap.c
 unit_test_eapol_LDADD = ell/libell-internal.la
 
 unit_test_ssid_to_utf8_SOURCES = src/util.h src/util.c \

src/eap.c

@@ -0,0 +1,409 @@
+/*
+ *
+ *  Wireless daemon for Linux
+ *
+ *  Copyright (C) 2013-2014  Intel Corporation. All rights reserved.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <ell/ell.h>
+
+#include "eap.h"
+
+struct l_queue *eap_methods;
+
+struct eap_state {
+	eap_tx_packet_func_t tx_packet;
+	eap_key_material_func_t set_key_material;
+	eap_complete_func_t complete;
+	void *user_data;
+	size_t mtu;
+
+	struct eap_method *method;
+	char *identity;
+
+	int last_id;
+	void *method_state;
+	bool method_success;
+	struct l_timeout *complete_timeout;
+};
+
+struct eap_state *eap_new(eap_tx_packet_func_t tx_packet,
+			eap_complete_func_t complete, void *user_data)
+{
+	struct eap_state *eap;
+
+	eap = l_new(struct eap_state, 1);
+
+	eap->last_id = -1;
+	eap->mtu = 1024;
+
+	eap->tx_packet = tx_packet;
+	eap->complete = complete;
+	eap->user_data = user_data;
+
+	return eap;
+}
+
+/*
+ * Setting a non-NULL set_key_material callback for this EAP instance will
+ * disable the legacy methods that don't generate key material, such
+ * as EAP-MD5.
+ */
+void eap_set_key_material_func(struct eap_state *eap,
+				eap_key_material_func_t func)
+{
+	eap->set_key_material = func;
+}
+
+void eap_free(struct eap_state *eap)
+{
+	if (eap->method_state)
+		eap->method->remove(eap);
+
+	if (eap->identity)
+		l_free(eap->identity);
+
+	l_timeout_remove(eap->complete_timeout);
+
+	l_free(eap);
+}
+
+/* Note: callers must check for a minimum value */
+void eap_set_mtu(struct eap_state *eap, size_t mtu)
+{
+	eap->mtu = mtu;
+}
+
+size_t eap_get_mtu(struct eap_state *eap)
+{
+	return eap->mtu;
+}
+
+void eap_send_response(struct eap_state *eap,
+			enum eap_request_type request_type,
+			uint8_t *buf, size_t len)
+{
+	buf[0] = EAP_CODE_RESPONSE;
+	buf[1] = eap->last_id;
+	l_put_be16(len, &buf[2]);
+	buf[4] = request_type;
+
+	eap->tx_packet(buf, len, eap->user_data);
+}
+
+static void eap_complete_timeout(struct l_timeout *timeout, void *user_data)
+{
+	struct eap_state *eap = user_data;
+
+	eap->complete_timeout = NULL;
+
+	eap->complete(eap->method_success ? EAP_RESULT_SUCCESS :
+			EAP_RESULT_TIMEOUT, eap->user_data);
+}
+
+void eap_start_complete_timeout(struct eap_state *eap)
+{
+	if (eap->complete_timeout)
+		l_timeout_remove(eap->complete_timeout);
+
+	eap->complete_timeout = l_timeout_create(5, eap_complete_timeout,
+							eap, NULL);
+}
+
+static void eap_send_identity_response(struct eap_state *eap, char *identity)
+{
+	int len = identity ? strlen(identity) : 0;
+	uint8_t buf[5 + len];
+
+	if (!identity)
+		identity = "";
+
+	memcpy(buf + 5, identity, len);
+
+	eap_send_response(eap, EAP_TYPE_IDENTITY, buf, len + 5);
+}
+
+static void eap_handle_request(struct eap_state *eap,
+				const uint8_t *pkt, size_t len)
+{
+	enum eap_request_type type;
+	uint8_t buf[10];
+	int buf_len;
+
+	if (len < 1)
+		/* Invalid packets to be ignored */
+		return;
+
+	type = pkt[0];
+
+	if (type >= __EAP_TYPE_MIN_METHOD) {
+		if (!eap->method || type != eap->method->request_type) {
+			l_warn("EAP server tried method %i while client was "
+					"configured for method %i",
+					type, eap->method->request_type);
+
+			goto unsupported_method;
+		}
+
+		eap->method->handle_request(eap, pkt + 1, len - 1);
+
+		return;
+	}
+
+	switch (type) {
+	case EAP_TYPE_IDENTITY:
+		if (len >= 2)
+			l_warn("EAP identity prompt: \"%.*s\"",
+					(int) len - 1, buf + 1);
+
+		eap_send_identity_response(eap, eap->identity);
+
+		return;
+
+	case EAP_TYPE_NOTIFICATION:
+		if (len < 2)
+			/* Invalid packets to be ignored */
+			return;
+
+		l_warn("EAP notification: \"%.*s\"", (int) len - 1, buf + 1);
+
+		eap_send_response(eap, EAP_TYPE_NOTIFICATION, buf, 5);
+
+		return;
+
+	default:
+	unsupported_method:
+		/* Send a legacy NAK response */
+		buf_len = 5;
+
+		buf[buf_len++] = eap->method ? eap->method->request_type : 0;
+
+		eap_send_response(eap, EAP_TYPE_NAK, buf, buf_len);
+		return;
+	}
+}
+
+void eap_rx_packet(struct eap_state *eap, const uint8_t *pkt, size_t len)
+{
+	uint8_t code, id;
+	uint16_t eap_len;
+
+	if (len < 4 || l_get_be16(&pkt[2]) < 4 || len < l_get_be16(&pkt[2]))
+		/* Invalid packets to be silently discarded */
+		return;
+
+	code = pkt[0];
+	id = pkt[1];
+	eap_len = l_get_be16(&pkt[2]);
+
+	switch ((enum eap_pkt_code) code) {
+	case EAP_CODE_REQUEST:
+		if (id == eap->last_id) {
+			/*
+			 * We should resend the last response if this ever
+			 * happens and if one was sent already.  This can
+			 * happen if the request_credentials callback needs
+			 * to wait for user input.  We can assume a reliable
+			 * lower layer but the retransmission behaviour is
+			 * decided by the authenticator (Section 4.3).
+			 */
+
+			return;
+		}
+
+		eap->last_id = id;
+
+		eap_handle_request(eap, pkt + 4, eap_len - 4);
+		return;
+
+	case EAP_CODE_FAILURE:
+	case EAP_CODE_SUCCESS:
+		l_timeout_remove(eap->complete_timeout);
+		eap->complete_timeout = NULL;
+
+		/* Section 4.2 */
+
+		if (id != eap->last_id)
+			return;
+
+		if (eap_len != 4)
+			/* Invalid packets to be silently discarded */
+			return;
+
+		if (code == EAP_CODE_SUCCESS && !eap->method_success)
+			/* "Canned" success packets to be discarded */
+			return;
+
+		if (code == EAP_CODE_FAILURE && eap->method_success)
+			/*
+			 * "On the peer, after success result indications have
+			 * been exchanged by both sides, a Failure packet MUST
+			 * be silently discarded."
+			 *
+			 * "Where the peer authenticates successfully to the
+			 * authenticator, but the authenticator does not send
+			 * a result indication, the authenticator MAY deny
+			 * access by sending a Failure packet where the peer
+			 * is not currently authorized for network access."
+			 * -- eap->method_success implies we've received
+			 * a full result indication.
+			 */
+			return;
+
+		if (eap->method_state)
+			eap->method->remove(eap);
+
+		eap->method = NULL;
+
+		eap->complete(code == EAP_CODE_SUCCESS ? EAP_RESULT_SUCCESS :
+				EAP_RESULT_FAIL, eap->user_data);
+		return;
+
+	default:
+		/* Invalid packets to be silently discarded */
+		return;
+	}
+}
+
+bool eap_load_settings(struct eap_state *eap, struct l_settings *settings,
+			const char *prefix)
+{
+	char setting[64];
+	const char *method_name;
+	const struct l_queue_entry *entry;
+	struct eap_method *method;
+
+	snprintf(setting, sizeof(setting), "%sMethod", prefix);
+	method_name = l_settings_get_value(settings, "Security", setting);
+
+	if (!method_name)
+		return false;
+
+	for (entry = l_queue_get_entries(eap_methods); entry;
+					entry = entry->next) {
+		method = entry->data;
+
+		if (method->probe(eap, method_name) == 0) {
+			eap->method = method;
+
+			break;
+		}
+	}
+
+	if (!eap->method)
+		return false;
+
+	/* Check if selected method is suitable for 802.1x */
+	if (eap->set_key_material && !eap->method->exports_msk) {
+		l_error("EAP method \"%s\" doesn't export key material",
+				method_name);
+
+		goto err;
+	}
+
+	snprintf(setting, sizeof(setting), "%sIdentity", prefix);
+	eap->identity = l_strdup(l_settings_get_value(settings,
+						"Security", setting));
+	if (!eap->identity) {
+		l_error("EAP Identity is missing");
+
+		goto err;
+	}
+
+	if (!eap->method->load_settings)
+		return true;
+
+	if (!eap->method->load_settings(eap, settings, prefix))
+		goto err;
+
+	return true;
+
+err:
+	if (eap->method->remove)
+		eap->method->remove(eap);
+
+	eap->method = NULL;
+
+	return false;
+}
+
+void eap_set_data(struct eap_state *eap, void *data)
+{
+	eap->method_state = data;
+}
+
+void *eap_get_data(struct eap_state *eap)
+{
+	return eap->method_state;
+}
+
+void eap_set_key_material(struct eap_state *eap,
+				const uint8_t *msk_data, size_t msk_len,
+				const uint8_t *emsk_data, size_t emsk_len,
+				const uint8_t *iv, size_t iv_len)
+{
+	if (!eap->set_key_material)
+		return;
+
+	eap->set_key_material(msk_data, msk_len, emsk_data, emsk_len,
+				iv, iv_len, eap->user_data);
+}
+
+void eap_method_success(struct eap_state *eap)
+{
+	eap->method_success = true;
+}
+
+void eap_method_error(struct eap_state *eap)
+{
+	/*
+	 * It looks like neither EAP nor EAP-TLS specify the error handling
+	 * behavior.
+	 */
+	eap->complete(EAP_RESULT_FAIL, eap->user_data);
+}
+
+void eap_save_last_id(struct eap_state *eap, uint8_t *last_id)
+{
+	*last_id = eap->last_id;
+}
+
+void eap_restore_last_id(struct eap_state *eap, uint8_t last_id)
+{
+	eap->last_id = last_id;
+}
+
+static void eap_register_method(struct eap_method *method)
+{
+	l_queue_push_head(eap_methods, method);
+}
+
+void eap_init(void) {
+	eap_methods = l_queue_new();
+}
+
+void eap_exit(void) {
+	l_queue_destroy(eap_methods, NULL);
+}

src/eap.h

@@ -0,0 +1,116 @@
+/*
+ *
+ *  Wireless daemon for Linux
+ *
+ *  Copyright (C) 2013-2014  Intel Corporation. All rights reserved.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <asm/byteorder.h>
+#include <linux/types.h>
+
+struct eap_state;
+
+enum eap_result {
+	EAP_RESULT_SUCCESS,
+	EAP_RESULT_FAIL,
+	EAP_RESULT_TIMEOUT,
+};
+
+typedef void (*eap_tx_packet_func_t)(const uint8_t *eap_data, size_t len,
+					void *user_data);
+typedef void (*eap_key_material_func_t)(const uint8_t *msk_data, size_t msk_len,
+				const uint8_t *emsk_data, size_t emsk_len,
+				const uint8_t *iv, size_t iv_len,
+				void *user_data);
+typedef void (*eap_complete_func_t)(enum eap_result result, void *user_data);
+
+struct eap_state *eap_new(eap_tx_packet_func_t tx_packet,
+			eap_complete_func_t complete, void *user_data);
+void eap_free(struct eap_state *eap);
+
+bool eap_load_settings(struct eap_state *eap, struct l_settings *settings,
+			const char *prefix);
+
+void eap_set_key_material_func(struct eap_state *eap,
+				eap_key_material_func_t func);
+
+void eap_set_mtu(struct eap_state *eap, size_t mtu);
+size_t eap_get_mtu(struct eap_state *eap);
+
+void eap_rx_packet(struct eap_state *eap, const uint8_t *pkt, size_t len);
+
+void eap_init(void);
+void eap_exit(void);
+
+/* EAP method API */
+
+enum eap_request_type {
+	EAP_TYPE_IDENTITY	= 1,
+	EAP_TYPE_NOTIFICATION	= 2,
+	EAP_TYPE_NAK		= 3,
+	__EAP_TYPE_MIN_METHOD	= 4,
+	EAP_TYPE_MD5_CHALLENGE	= 4,
+	EAP_TYPE_TLS_EAP	= 13,
+	EAP_TYPE_TTLS		= 21,
+	EAP_TYPE_EXPANDED	= 254,
+};
+
+enum eap_pkt_code {
+	EAP_CODE_REQUEST	= 1,
+	EAP_CODE_RESPONSE	= 2,
+	EAP_CODE_SUCCESS	= 3,
+	EAP_CODE_FAILURE	= 4,
+};
+
+struct eap_method {
+	enum eap_request_type request_type;
+	bool exports_msk;
+	const char *name;
+
+	int (*probe)(struct eap_state *eap, const char *method_string);
+	void (*remove)(struct eap_state *eap);
+
+	bool (*load_settings)(struct eap_state *eap,
+				struct l_settings *settings,
+				const char *prefix);
+
+	void (*handle_request)(struct eap_state *eap,
+				const uint8_t *pkt, size_t len);
+};
+
+void eap_set_data(struct eap_state *eap, void *data);
+void *eap_get_data(struct eap_state *eap);
+
+void eap_send_response(struct eap_state *eap,
+			enum eap_request_type request_type,
+			uint8_t *buf, size_t len);
+
+void eap_set_key_material(struct eap_state *eap,
+				const uint8_t *msk_data, size_t msk_len,
+				const uint8_t *emsk_data, size_t emsk_len,
+				const uint8_t *iv, size_t iv_len);
+
+void eap_start_complete_timeout(struct eap_state *eap);
+
+void eap_method_success(struct eap_state *eap);
+void eap_method_error(struct eap_state *eap);
+
+void eap_save_last_id(struct eap_state *eap, uint8_t *last_id);
+void eap_restore_last_id(struct eap_state *eap, uint8_t last_id);