1 files changed, 303 insertions, 0 deletions
diff --git a/src/libcharon/plugins/eap_md5/eap_md5.c b/src/libcharon/plugins/eap_md5/eap_md5.c
new file mode 100644
index 000000000..0eda8f755
--- /dev/null
+++ b/src/libcharon/plugins/eap_md5/eap_md5.c
@@ -0,0 +1,303 @@
+/*
+ * Copyright (C) 2007 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program 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 General Public License
+ * for more details.
+ */
+
+#include "eap_md5.h"
+
+#include <daemon.h>
+#include <library.h>
+#include <crypto/hashers/hasher.h>
+
+typedef struct private_eap_md5_t private_eap_md5_t;
+
+/**
+ * Private data of an eap_md5_t object.
+ */
+struct private_eap_md5_t {
+
+	/**
+	 * Public authenticator_t interface.
+	 */
+	eap_md5_t public;
+
+	/**
+	 * ID of the server
+	 */
+	identification_t *server;
+
+	/**
+	 * ID of the peer
+	 */
+	identification_t *peer;
+
+	/**
+	 * challenge sent by the server
+	 */
+	chunk_t challenge;
+
+	/**
+	 * EAP message identififier
+	 */
+	u_int8_t identifier;
+};
+
+typedef struct eap_md5_header_t eap_md5_header_t;
+
+/**
+ * packed eap MD5 header struct
+ */
+struct eap_md5_header_t {
+	/** EAP code (REQUEST/RESPONSE) */
+	u_int8_t code;
+	/** unique message identifier */
+	u_int8_t identifier;
+	/** length of whole message */
+	u_int16_t length;
+	/** EAP type */
+	u_int8_t type;
+	/** length of value (challenge) */
+	u_int8_t value_size;
+	/** actual value */
+	u_int8_t value[];
+} __attribute__((__packed__));
+
+#define CHALLENGE_LEN 16
+#define PAYLOAD_LEN (CHALLENGE_LEN + sizeof(eap_md5_header_t))
+
+/**
+ * Hash the challenge string, create response
+ */
+static status_t hash_challenge(private_eap_md5_t *this, chunk_t *response,
+							   identification_t *me, identification_t *other)
+{
+	shared_key_t *shared;
+	chunk_t concat;
+	hasher_t *hasher;
+
+	shared = charon->credentials->get_shared(charon->credentials, SHARED_EAP,
+											 me, other);
+	if (shared == NULL)
+	{
+		DBG1(DBG_IKE, "no EAP key found for hosts '%Y' - '%Y'", me, other);
+		return NOT_FOUND;
+	}
+	concat = chunk_cata("ccc", chunk_from_thing(this->identifier),
+						shared->get_key(shared), this->challenge);
+	shared->destroy(shared);
+	hasher = lib->crypto->create_hasher(lib->crypto, HASH_MD5);
+	if (hasher == NULL)
+	{
+		DBG1(DBG_IKE, "EAP-MD5 failed, MD5 not supported");
+		return FAILED;
+	}
+	hasher->allocate_hash(hasher, concat, response);
+	hasher->destroy(hasher);
+	return SUCCESS;
+}
+
+/**
+ * Implementation of eap_method_t.initiate for the peer
+ */
+static status_t initiate_peer(private_eap_md5_t *this, eap_payload_t **out)
+{
+	/* peer never initiates */
+	return FAILED;
+}
+
+/**
+ * Implementation of eap_method_t.initiate for the server
+ */
+static status_t initiate_server(private_eap_md5_t *this, eap_payload_t **out)
+{
+	rng_t *rng;
+	eap_md5_header_t *req;
+
+	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+	if (!rng)
+	{
+		return FAILED;
+	}
+	rng->allocate_bytes(rng, CHALLENGE_LEN, &this->challenge);
+	rng->destroy(rng);
+
+	req = alloca(PAYLOAD_LEN);
+	req->length = htons(PAYLOAD_LEN);
+	req->code = EAP_REQUEST;
+	req->identifier = this->identifier;
+	req->type = EAP_MD5;
+	req->value_size = this->challenge.len;
+	memcpy(req->value, this->challenge.ptr, this->challenge.len);
+
+	*out = eap_payload_create_data(chunk_create((void*)req, PAYLOAD_LEN));
+	return NEED_MORE;
+}
+
+/**
+ * Implementation of eap_method_t.process for the peer
+ */
+static status_t process_peer(private_eap_md5_t *this,
+							 eap_payload_t *in, eap_payload_t **out)
+{
+	chunk_t response;
+	chunk_t data;
+	eap_md5_header_t *req;
+
+	this->identifier = in->get_identifier(in);
+	data = in->get_data(in);
+	this->challenge = chunk_clone(chunk_skip(data, 6));
+	if (data.len < 6 || this->challenge.len < *(data.ptr + 5))
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MD5 message");
+		return FAILED;
+	}
+	if (hash_challenge(this, &response, this->peer, this->server) != SUCCESS)
+	{
+		return FAILED;
+	}
+	req = alloca(PAYLOAD_LEN);
+	req->length = htons(PAYLOAD_LEN);
+	req->code = EAP_RESPONSE;
+	req->identifier = this->identifier;
+	req->type = EAP_MD5;
+	req->value_size = response.len;
+	memcpy(req->value, response.ptr, response.len);
+	chunk_free(&response);
+
+	*out = eap_payload_create_data(chunk_create((void*)req, PAYLOAD_LEN));
+	return NEED_MORE;
+}
+
+/**
+ * Implementation of eap_method_t.process for the server
+ */
+static status_t process_server(private_eap_md5_t *this,
+							   eap_payload_t *in, eap_payload_t **out)
+{
+	chunk_t response, expected;
+	chunk_t data;
+
+	if (this->identifier != in->get_identifier(in))
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MD5 message");
+		return FAILED;
+	}
+	if (hash_challenge(this, &expected, this->server, this->peer) != SUCCESS)
+	{
+		return FAILED;
+	}
+	data = in->get_data(in);
+	response = chunk_skip(data, 6);
+
+	if (response.len < expected.len ||
+		!memeq(response.ptr, expected.ptr, expected.len))
+	{
+		chunk_free(&expected);
+		DBG1(DBG_IKE, "EAP-MD5 verification failed");
+		return FAILED;
+	}
+	chunk_free(&expected);
+	return SUCCESS;
+}
+
+/**
+ * Implementation of eap_method_t.get_type.
+ */
+static eap_type_t get_type(private_eap_md5_t *this, u_int32_t *vendor)
+{
+	*vendor = 0;
+	return EAP_MD5;
+}
+
+/**
+ * Implementation of eap_method_t.get_msk.
+ */
+static status_t get_msk(private_eap_md5_t *this, chunk_t *msk)
+{
+	return FAILED;
+}
+
+/**
+ * Implementation of eap_method_t.is_mutual.
+ */
+static bool is_mutual(private_eap_md5_t *this)
+{
+	return FALSE;
+}
+
+/**
+ * Implementation of eap_method_t.destroy.
+ */
+static void destroy(private_eap_md5_t *this)
+{
+	this->peer->destroy(this->peer);
+	this->server->destroy(this->server);
+	chunk_free(&this->challenge);
+	free(this);
+}
+
+/**
+ * Generic constructor
+ */
+static private_eap_md5_t *eap_md5_create_generic(identification_t *server,
+												 identification_t *peer)
+{
+	private_eap_md5_t *this = malloc_thing(private_eap_md5_t);
+
+	this->public.eap_method_interface.initiate = NULL;
+	this->public.eap_method_interface.process = NULL;
+	this->public.eap_method_interface.get_type = (eap_type_t(*)(eap_method_t*,u_int32_t*))get_type;
+	this->public.eap_method_interface.is_mutual = (bool(*)(eap_method_t*))is_mutual;
+	this->public.eap_method_interface.get_msk = (status_t(*)(eap_method_t*,chunk_t*))get_msk;
+	this->public.eap_method_interface.destroy = (void(*)(eap_method_t*))destroy;
+
+	/* private data */
+	this->peer = peer->clone(peer);
+	this->server = server->clone(server);
+	this->challenge = chunk_empty;
+	this->identifier = 0;
+
+	return this;
+}
+
+/*
+ * see header
+ */
+eap_md5_t *eap_md5_create_server(identification_t *server, identification_t *peer)
+{
+	private_eap_md5_t *this = eap_md5_create_generic(server, peer);
+
+	this->public.eap_method_interface.initiate = (status_t(*)(eap_method_t*,eap_payload_t**))initiate_server;
+	this->public.eap_method_interface.process = (status_t(*)(eap_method_t*,eap_payload_t*,eap_payload_t**))process_server;
+
+	/* generate a non-zero identifier */
+	do {
+		this->identifier = random();
+	} while (!this->identifier);
+
+	return &this->public;
+}
+
+/*
+ * see header
+ */
+eap_md5_t *eap_md5_create_peer(identification_t *server, identification_t *peer)
+{
+	private_eap_md5_t *this = eap_md5_create_generic(server, peer);
+
+	this->public.eap_method_interface.initiate = (status_t(*)(eap_method_t*,eap_payload_t**))initiate_peer;
+	this->public.eap_method_interface.process = (status_t(*)(eap_method_t*,eap_payload_t*,eap_payload_t**))process_peer;
+
+	return &this->public;
+}
+