adding plugin for EAP-MS-CHAPv2

1 files changed, 1199 insertions, 0 deletions

diff --git a/src/charon/plugins/eap_mschapv2/eap_mschapv2.c b/src/charon/plugins/eap_mschapv2/eap_mschapv2.c
new file mode 100644
index 000000000..56b3667ed
--- /dev/null
+++ b/src/charon/plugins/eap_mschapv2/eap_mschapv2.c
@@ -0,0 +1,1199 @@
+/*
+ * Copyright (C) 2009 Tobias Brunner
+ * 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.
+ *
+ * $Id$
+ */
+
+#include "eap_mschapv2.h"
+
+#include <daemon.h>
+#include <library.h>
+#include <utils/enumerator.h>
+#include <crypto/crypters/crypter.h>
+#include <crypto/hashers/hasher.h>
+
+typedef struct private_eap_mschapv2_t private_eap_mschapv2_t;
+
+/**
+ * Private data of an eap_mschapv2_t object.
+ */
+struct private_eap_mschapv2_t
+{
+	/**
+	 * Public authenticator_t interface.
+	 */
+	eap_mschapv2_t public;
+	
+	/**
+	 * ID of the server
+	 */
+	identification_t *server;
+	
+	/**
+	 * ID of the peer
+	 */
+	identification_t *peer;
+	
+	/**
+	 * challenge sent by the server
+	 */
+	chunk_t challenge;
+	
+	/**
+	 * generated NT-Response
+	 */
+	chunk_t nt_response;
+	
+	/**
+	 * generated Authenticator Response
+	 */
+	chunk_t auth_response;
+	
+	/**
+	 * generated MSK
+	 */
+	chunk_t msk;
+	
+	/**
+	 * EAP message identifier
+	 */
+	u_int8_t identifier;
+	
+	/**
+	 * MS-CHAPv2-ID (session ID, increases with each retry)
+	 */
+	u_int8_t mschapv2id;
+	
+	/**
+	 * Number of retries
+	 */
+	int retries;
+};
+
+/**
+ * OpCodes
+ */
+enum mschapv2_opcode_t
+{
+	MSCHAPV2_CHALLENGE = 1,
+	MSCHAPV2_RESPONSE = 2,
+	MSCHAPV2_SUCCESS = 3,
+	MSCHAPV2_FAILURE = 4,
+	MSCHAPV2_CHANGE_PASSWORD = 7,
+};
+
+/**
+ * Names for OpCodes
+ */
+ENUM_BEGIN(mschapv2_opcode_names, MSCHAPV2_CHALLENGE, MSCHAPV2_FAILURE,
+		"CHALLENGE",
+		"RESPONSE",
+		"SUCCESS",
+		"FAILURE");
+ENUM_NEXT(mschapv2_opcode_names, MSCHAPV2_CHANGE_PASSWORD, MSCHAPV2_CHANGE_PASSWORD, MSCHAPV2_FAILURE,
+		"CHANGE_PASSWORD");
+ENUM_END(mschapv2_opcode_names, MSCHAPV2_CHANGE_PASSWORD);
+
+/**
+ * Error codes
+ */
+enum mschapv2_error_t
+{
+	ERROR_RESTRICTED_LOGON_HOURS	= 646,
+	ERROR_ACCT_DISABLED				= 647,
+	ERROR_PASSWD_EXPIRED			= 648,
+	ERROR_NO_DIALIN_PERMISSION		= 649,
+	ERROR_AUTHENTICATION_FAILURE	= 691,
+	ERROR_CHANGING_PASSWORD			= 709,
+};
+
+/**
+ * Names for error codes
+ */
+ENUM_BEGIN(mschapv2_error_names, ERROR_RESTRICTED_LOGON_HOURS, ERROR_NO_DIALIN_PERMISSION,
+		"ERROR_RESTRICTED_LOGON_HOURS",
+		"ERROR_ACCT_DISABLED",
+		"ERROR_PASSWD_EXPIRED",
+		"ERROR_NO_DIALIN_PERMISSION");
+ENUM_NEXT(mschapv2_error_names, ERROR_AUTHENTICATION_FAILURE, ERROR_AUTHENTICATION_FAILURE, ERROR_NO_DIALIN_PERMISSION,
+		"ERROR_AUTHENTICATION_FAILURE");
+ENUM_NEXT(mschapv2_error_names, ERROR_CHANGING_PASSWORD, ERROR_CHANGING_PASSWORD, ERROR_AUTHENTICATION_FAILURE,
+		"ERROR_CHANGING_PASSWORD");
+ENUM_END(mschapv2_error_names, ERROR_CHANGING_PASSWORD);
+
+/* Length of the challenge */
+#define CHALLENGE_LEN 16
+/* Length of the response (see eap_mschapv2_response_t) */
+#define RESPONSE_LEN 49
+/* Length of the authenticator response string ("S=<...>") */
+#define AUTH_RESPONSE_LEN 42
+/* Name we send as authenticator */
+#define MSCHAPV2_HOST_NAME "strongSwan"
+/* Message sent on success */
+#define SUCCESS_MESSAGE " M=Welcome to strongSwan"
+/* Message sent on failure */
+#define FAILURE_MESSAGE "E=691 R=1 C="
+/* Length of the complete failure message */
+#define FAILURE_MESSAGE_LEN (sizeof(FAILURE_MESSAGE) + CHALLENGE_LEN * 2)
+
+/* Number of seconds to delay retries */
+#define RETRY_DELAY 2
+/* Maximum number of retries */
+#define MAX_RETRIES 2
+
+typedef struct eap_mschapv2_header_t eap_mschapv2_header_t;
+typedef struct eap_mschapv2_challenge_t eap_mschapv2_challenge_t;
+typedef struct eap_mschapv2_response_t eap_mschapv2_response_t;
+
+/**
+ * packed EAP-MS-CHAPv2 header struct
+ */
+struct eap_mschapv2_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;
+	/** MS-CHAPv2 OpCode */
+	u_int8_t opcode;
+	/** MS-CHAPv2-ID (equals identifier) */
+	u_int8_t ms_chapv2_id;
+	/** MS-Length (defined as length - 5) */
+	u_int16_t ms_length;
+	/** packet data (determined by OpCode) */
+	u_int8_t data[];
+}__attribute__((__packed__));
+
+/**
+ * packed data for a MS-CHAPv2 Challenge packet
+ */
+struct eap_mschapv2_challenge_t
+{
+	/** Value-Size */
+	u_int8_t value_size;
+	/** Challenge */
+	u_int8_t challenge[CHALLENGE_LEN];
+	/** Name */
+	u_int8_t name[];
+}__attribute__((__packed__));
+
+/**
+ * packed data for a MS-CHAPv2 Response packet
+ */
+struct eap_mschapv2_response_t
+{
+	/** Value-Size */
+	u_int8_t value_size;
+	/** Response */
+	struct
+	{
+		/* Peer-Challenge*/
+		u_int8_t peer_challenge[CHALLENGE_LEN];
+		/* Reserved (=zero) */
+		u_int8_t peer_reserved[8];
+		/* NT-Response */
+		u_int8_t nt_response[24];
+		/* Flags (=zero) */
+		u_int8_t flags;
+	} response;
+	/** Name */
+	u_int8_t name[];
+}__attribute__((__packed__));
+
+/**
+ * Length of the MS-CHAPv2 header
+ */
+#define HEADER_LEN (sizeof(eap_mschapv2_header_t))
+
+/**
+ * Length of the header for MS-CHAPv2 success/failure packets (does not include
+ * MS-CHAPv2-ID and MS-Length, i.e. 3 octets)
+ */
+#define SHORT_HEADER_LEN (HEADER_LEN - 3)
+
+/**
+ * The minimum length of an MS-CHAPv2 Challenge packet (the name MUST be
+ * at least one octet)
+ */
+#define CHALLENGE_PAYLOAD_LEN (HEADER_LEN + sizeof(eap_mschapv2_challenge_t))
+
+/**
+ * The minimum length of an MS-CHAPv2 Response packet
+ */
+#define RESPONSE_PAYLOAD_LEN (HEADER_LEN + sizeof(eap_mschapv2_response_t))
+
+
+/**
+ * Expand a 56-bit key to a 64-bit DES key by adding parity bits (odd parity)
+ */
+static chunk_t ExpandDESKey(chunk_t key)
+{
+	static const u_char bitmask[] =	{ 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 };
+	int i;
+	u_char carry = 0;
+	chunk_t expanded;
+	
+	/* expand the 7 octets to 8 octets */
+	expanded = chunk_alloc(8);
+	for (i = 0; i < 7; i++)
+	{
+		expanded.ptr[i] = ((key.ptr[i] & bitmask[i]) >> i) | (carry << (8 - i));
+		carry = key.ptr[i] & ~bitmask[i];
+	}
+	expanded.ptr[7] = carry << 1;
+	
+	/* add parity bits to each octet */
+	for (i = 0; i < 8; i++)
+	{
+		u_char val = expanded.ptr[i];
+		val = (val ^ (val >> 4)) & 0x0f;
+		expanded.ptr[i] |= (0x9669 >> val) & 1;
+	}
+	return expanded;
+}
+
+/**
+ * Calculate the NT password hash (i.e. hash the (unicode) password with MD4) 
+ */
+static status_t NtPasswordHash(chunk_t password, chunk_t *password_hash)
+{
+	hasher_t *hasher;
+	hasher = lib->crypto->create_hasher(lib->crypto, HASH_MD4);
+	if (hasher == NULL)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed, MD4 not supported");
+		return FAILED;
+	}
+	hasher->allocate_hash(hasher, password, password_hash);
+	hasher->destroy(hasher);
+	return SUCCESS;
+}
+
+/**
+ * Calculate the challenge hash (i.e. hash [peer_challenge | server_challenge |
+ * username (without domain part)] with SHA1) 
+ */
+static status_t ChallengeHash(chunk_t peer_challenge, chunk_t server_challenge,
+							  chunk_t username, chunk_t *challenge_hash)
+{
+	chunk_t concat;
+	hasher_t *hasher;
+	hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
+	if (hasher == NULL)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed, SHA1 not supported");
+		return FAILED;
+	}
+	concat = chunk_cata("ccc", peer_challenge, server_challenge, username);
+	hasher->allocate_hash(hasher, concat, challenge_hash);
+	hasher->destroy(hasher);
+	/* we need only the first 8 octets */
+	challenge_hash->len = 8;
+	return SUCCESS;
+}
+
+/**
+ * Calculate the challenge response (i.e. expand password_hash to three DES keys
+ * and then encrypt the 8-octet challenge_hash with these keys and concatenate
+ * the results).
+ */
+static status_t ChallengeResponse(chunk_t challenge_hash, chunk_t password_hash,
+								  chunk_t *response)
+{
+	int i;
+	crypter_t *crypter;
+	chunk_t keys[3], z_password_hash;
+	crypter = lib->crypto->create_crypter(lib->crypto, ENCR_DES_ECB, 64);
+	if (crypter == NULL)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed, DES-ECB not supported");
+		return FAILED;
+	}
+	/* prepare keys: first pad password_hash to 21 octets, these get then split
+	 * into 7-octet chunks, which then get expanded into 8-octet DES keys */
+	z_password_hash = chunk_alloca(21);
+	memset(z_password_hash.ptr, 0, z_password_hash.len);
+	memcpy(z_password_hash.ptr, password_hash.ptr, password_hash.len);
+	chunk_split(z_password_hash, "mmm", 7, &keys[0], 7, &keys[1], 7, &keys[2]);
+	
+	*response = chunk_alloc(24);
+	for (i = 0; i < 3; i++)
+	{
+		chunk_t expanded, encrypted;
+		expanded = ExpandDESKey(keys[i]);
+		crypter->set_key(crypter, expanded);
+		crypter->encrypt(crypter, challenge_hash, chunk_empty, &encrypted);
+		memcpy(&response->ptr[i * 8], encrypted.ptr, encrypted.len);
+		chunk_clear(&expanded);
+	}
+	crypter->destroy(crypter);
+	return SUCCESS;
+}
+
+/**
+ * Computes the authenticator response
+ */
+static status_t AuthenticatorResponse(chunk_t password_hash_hash,
+		chunk_t challenge_hash, chunk_t nt_response, chunk_t *response)
+{
+	static u_int8_t magic1_data[] =
+				{ 0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
+				  0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
+				  0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
+				  0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74 };
+	static u_int8_t magic2_data[] =
+				{ 0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
+				  0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
+				  0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
+				  0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
+				  0x6E };
+	static const chunk_t magic1 = chunk_from_buf(magic1_data);
+	static const chunk_t magic2 = chunk_from_buf(magic2_data);
+	
+	status_t status = FAILED;
+	chunk_t digest = chunk_empty, concat;
+	hasher_t *hasher;
+	
+	hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
+	if (hasher == NULL)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed, SHA1 not supported");
+		return FAILED;
+	}
+	
+	concat = chunk_cata("ccc", password_hash_hash, nt_response, magic1);
+	hasher->allocate_hash(hasher, concat, &digest);
+	concat = chunk_cata("ccc", digest, challenge_hash, magic2);
+	hasher->allocate_hash(hasher, concat, response);
+	
+	hasher->destroy(hasher);
+	chunk_free(&digest);
+	return SUCCESS;
+}
+
+/**
+ * Generate the master session key according to RFC3079
+ */
+static status_t GenerateMSK(chunk_t password_hash_hash,
+							chunk_t nt_response, chunk_t *msk)
+{
+	static u_int8_t magic1_data[] =
+		{ 0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
+		  0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
+		  0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79 };
+	static u_int8_t magic2_data[] =
+		{ 0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
+		  0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
+		  0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
+		  0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
+		  0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
+		  0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
+		  0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
+		  0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
+		  0x6b, 0x65, 0x79, 0x2e };
+	static u_int8_t magic3_data[] =
+		{ 0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
+		  0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
+		  0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
+		  0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
+		  0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
+		  0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
+		  0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
+		  0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
+		  0x6b, 0x65, 0x79, 0x2e };
+	static u_int8_t shapad1_data[] =
+		{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+	static u_int8_t shapad2_data[] =
+		{ 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+		  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+		  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
+		  0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2 };
+	static const chunk_t magic1 = chunk_from_buf(magic1_data);
+	static const chunk_t magic2 = chunk_from_buf(magic2_data);
+	static const chunk_t magic3 = chunk_from_buf(magic3_data);
+	static const chunk_t shapad1 = chunk_from_buf(shapad1_data);
+	static const chunk_t shapad2 = chunk_from_buf(shapad2_data);
+	static const chunk_t keypad = { shapad1_data, 16 };
+	
+	chunk_t concat, master_key, master_receive_key, master_send_key;
+	hasher_t *hasher;
+	
+	hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
+	if (hasher == NULL)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed, SHA1 not supported");
+		return FAILED;
+	}
+	
+	concat = chunk_cata("ccc", password_hash_hash, nt_response, magic1);
+	hasher->allocate_hash(hasher, concat, &master_key);
+	master_key.len = 16;
+	
+	concat = chunk_cata("cccc", master_key, shapad1, magic2, shapad2);
+	hasher->allocate_hash(hasher, concat, &master_receive_key);
+	master_receive_key.len = 16;
+	
+	concat = chunk_cata("cccc", master_key, shapad1, magic3, shapad2);
+	hasher->allocate_hash(hasher, concat, &master_send_key);
+	master_send_key.len = 16;
+	
+	*msk = chunk_cat("cccc", master_receive_key, keypad, master_send_key, keypad);
+	
+	hasher->destroy(hasher);
+	chunk_free(&master_key);
+	chunk_free(&master_receive_key);
+	chunk_free(&master_send_key);
+	return SUCCESS;
+}
+
+static status_t GenerateStuff(private_eap_mschapv2_t *this,
+							  chunk_t server_challenge, chunk_t peer_challenge,
+							  chunk_t username, chunk_t password)
+{
+	status_t status = FAILED;
+	chunk_t password_hash = chunk_empty, password_hash_hash = chunk_empty,
+			challenge_hash = chunk_empty;
+	
+	if (NtPasswordHash(password, &password_hash) != SUCCESS)
+	{
+		goto error;
+	}
+	if (NtPasswordHash(password_hash, &password_hash_hash) != SUCCESS)
+	{
+		goto error;
+	}
+	if (ChallengeHash(peer_challenge, server_challenge, username,
+					  &challenge_hash) != SUCCESS)
+	{
+		goto error;
+	}
+	
+	if (ChallengeResponse(challenge_hash, password_hash,
+						  &this->nt_response) != SUCCESS)
+	{
+		goto error;
+	}
+	if (AuthenticatorResponse(password_hash_hash, challenge_hash,
+							  this->nt_response, &this->auth_response) != SUCCESS)
+	{
+		goto error;
+	}
+	if (GenerateMSK(password_hash_hash, this->nt_response, &this->msk) != SUCCESS)
+	{
+		goto error;
+	}
+	
+	status = SUCCESS;
+	
+error:
+	chunk_free(&password_hash);
+	chunk_free(&password_hash_hash);
+	chunk_free(&challenge_hash);
+	return status;
+}
+
+/**
+ * Converts an ASCII string into a UTF-16 (little-endian) string
+ */
+static chunk_t ascii_to_unicode(chunk_t ascii)
+{
+	int i;
+	chunk_t unicode = chunk_alloc(ascii.len * 2);
+	for (i = 0; i < ascii.len; i++)
+	{
+		unicode.ptr[i * 2] = ascii.ptr[i];
+		unicode.ptr[i * 2 + 1] = 0;
+	}
+	return unicode;
+}
+
+/**
+ * Returns a chunk of just the username part of the given user identity.
+ * Note: the chunk points to internal data of the identification.
+ */
+static chunk_t extract_username(identification_t* identification)
+{
+	char *has_domain;
+	chunk_t id;
+	id = identification->get_encoding(identification);
+	has_domain = (char*)memrchr(id.ptr, '\\', id.len);
+	if (has_domain)
+	{
+		int len;
+		has_domain++; /* skip the backslash */
+		len = id.len - ((u_char*)has_domain - id.ptr);
+		return len > 0 ? chunk_create(has_domain, len) : chunk_empty;
+	}
+	return id;
+}
+
+
+/**
+ * Implementation of eap_method_t.initiate for the peer
+ */
+static status_t initiate_peer(private_eap_mschapv2_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_mschapv2_t *this, eap_payload_t **out)
+{
+	rng_t *rng;
+	eap_mschapv2_header_t *eap;
+	eap_mschapv2_challenge_t *cha;
+	const char *name = MSCHAPV2_HOST_NAME;
+	u_int16_t len = CHALLENGE_PAYLOAD_LEN + sizeof(MSCHAPV2_HOST_NAME) - 1;
+	
+	DBG1(DBG_IKE, "initiating EAP-MS-CHAPv2");
+	
+	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+	if (!rng)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed, no RNG");
+		return FAILED;
+	}
+	rng->allocate_bytes(rng, CHALLENGE_LEN, &this->challenge);
+	rng->destroy(rng);
+	
+	eap = alloca(len);
+	eap->code = EAP_REQUEST;
+	eap->identifier = this->identifier;
+	eap->length = htons(len);
+	eap->type = EAP_MSCHAPV2;
+	eap->opcode = MSCHAPV2_CHALLENGE;
+	eap->ms_chapv2_id = this->mschapv2id;
+	eap->ms_length = htons(len - 5);
+	
+	cha = (eap_mschapv2_challenge_t*)eap->data;
+	cha->value_size = CHALLENGE_LEN;
+	memcpy(cha->challenge, this->challenge.ptr, this->challenge.len);
+	memcpy(cha->name, name, sizeof(MSCHAPV2_HOST_NAME) - 1);
+	
+	*out = eap_payload_create_data(chunk_create((void*) eap, len));
+	return NEED_MORE;
+}
+
+
+/**
+ * Process MS-CHAPv2 Challenge Requests
+ */
+static status_t process_peer_challenge(private_eap_mschapv2_t *this,
+									   eap_payload_t *in, eap_payload_t **out)
+{
+	rng_t *rng;
+	eap_mschapv2_header_t *eap;
+	eap_mschapv2_challenge_t *cha;
+	eap_mschapv2_response_t *res;
+	shared_key_t *shared;
+	chunk_t data, peer_challenge, username, password;
+	u_int16_t len = RESPONSE_PAYLOAD_LEN;
+	
+	data = in->get_data(in);
+	eap = (eap_mschapv2_header_t*)data.ptr;
+	
+	/* the name MUST be at least one octet long */
+	if (data.len < CHALLENGE_PAYLOAD_LEN + 1)
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: too short");
+		return FAILED;
+	}
+	
+	cha = (eap_mschapv2_challenge_t*)eap->data;
+			
+	if (cha->value_size != CHALLENGE_LEN)
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: invalid challenge size");
+		return FAILED;
+	}
+			
+	this->mschapv2id = eap->ms_chapv2_id;
+	this->challenge = chunk_clone(chunk_create(cha->challenge, CHALLENGE_LEN));
+			
+	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+	if (!rng)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed, no RNG");
+		return FAILED;
+	}
+	peer_challenge = chunk_alloca(CHALLENGE_LEN);
+	rng->get_bytes(rng, CHALLENGE_LEN, peer_challenge.ptr);
+	rng->destroy(rng);
+			
+	shared = charon->credentials->get_shared(charon->credentials,
+											 SHARED_EAP, this->server, this->peer);
+	if (shared == NULL)
+	{
+		DBG1(DBG_IKE, "no EAP key found for hosts '%D' - '%D'",
+				this->server, this->peer);
+		return NOT_FOUND;
+	}
+	
+	password = ascii_to_unicode(shared->get_key(shared));
+	shared->destroy(shared);
+	
+	username = extract_username(this->peer);
+	len += username.len;
+			
+	if (GenerateStuff(this, this->challenge, peer_challenge, username, password) != SUCCESS)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 generating NT-Response failed");
+		chunk_clear(&password);
+		return FAILED;
+	}
+	chunk_clear(&password);
+			
+	eap = alloca(len);
+	eap->code = EAP_RESPONSE;
+	eap->identifier = this->identifier;
+	eap->length = htons(len);
+	eap->type = EAP_MSCHAPV2;
+	eap->opcode = MSCHAPV2_RESPONSE;
+	eap->ms_chapv2_id = this->mschapv2id;
+	eap->ms_length = htons(len - 5);
+	
+	res = (eap_mschapv2_response_t*)eap->data;
+	res->value_size = RESPONSE_LEN;
+	memset(&res->response, 0, RESPONSE_LEN);
+	memcpy(res->response.peer_challenge, peer_challenge.ptr, peer_challenge.len);
+	memcpy(res->response.nt_response, this->nt_response.ptr, this->nt_response.len);
+	
+	username = this->peer->get_encoding(this->peer);
+	memcpy(res->name, username.ptr, username.len);
+	
+	*out = eap_payload_create_data(chunk_create((void*) eap, len));
+	return NEED_MORE;
+}
+
+/**
+ * Process MS-CHAPv2 Success Requests
+ */
+static status_t process_peer_success(private_eap_mschapv2_t *this,
+									  eap_payload_t *in, eap_payload_t **out)
+{
+	status_t status = FAILED;
+	enumerator_t *enumerator;
+	eap_mschapv2_header_t *eap;
+	chunk_t data, auth_string = chunk_empty;
+	char *message, *token, *msg = NULL;
+	int message_len;
+	u_int16_t len = SHORT_HEADER_LEN;
+	
+	data = in->get_data(in);
+	eap = (eap_mschapv2_header_t*)data.ptr;
+	
+	if (data.len < AUTH_RESPONSE_LEN)
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: too short");
+		return FAILED;
+	}
+	
+	message_len = data.len - HEADER_LEN + 1; /* + null byte */
+	message = malloc(message_len);
+	memcpy(message, eap->data, message_len - 1);
+	message[message_len] = '\0';
+	
+	/* S=<auth_string> M=<msg> */
+	enumerator = enumerator_create_token(message, " ", " ");
+	while (enumerator->enumerate(enumerator, &token))
+	{
+		if (strneq(token, "S=", 2))
+		{
+			chunk_t hex;
+			token += 2;
+			if (strlen(token) != AUTH_RESPONSE_LEN - 2)
+			{
+				DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: invalid auth string");
+				goto error;
+			}
+			hex = chunk_create(token, AUTH_RESPONSE_LEN - 2);
+			auth_string = chunk_from_hex(hex, NULL);
+		}
+		else if (strneq(token, "M=", 2))
+		{
+			token += 2;
+			msg = strdup(token);
+		}
+	}
+	enumerator->destroy(enumerator);
+			
+	if (auth_string.ptr == NULL)	
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: auth string missing");
+		goto error;
+	}
+	
+	if (!chunk_equals(this->auth_response, auth_string))
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 verification failed");
+		goto error;
+	}
+	
+	DBG1(DBG_IKE, "EAP-MS-CHAPv2 succeeded: '%s'", msg);
+	
+	eap = alloca(len);
+	eap->code = EAP_RESPONSE;
+	eap->identifier = this->identifier;
+	eap->length = htons(len);
+	eap->type = EAP_MSCHAPV2;
+	eap->opcode = MSCHAPV2_SUCCESS;
+	
+	*out = eap_payload_create_data(chunk_create((void*) eap, len));
+	status = NEED_MORE;
+	
+error:
+	chunk_free(&auth_string);
+	free(message);
+	free(msg);
+	return status;
+}
+
+static status_t process_peer_failure(private_eap_mschapv2_t *this,
+									 eap_payload_t *in, eap_payload_t **out)
+{
+	status_t status = FAILED;
+	enumerator_t *enumerator;
+	eap_mschapv2_header_t *eap;
+	chunk_t data;
+	char *message, *token, *msg = NULL;
+	int message_len, error, retryable;
+	chunk_t challenge = chunk_empty;
+	u_int16_t len = SHORT_HEADER_LEN;
+	
+	data = in->get_data(in);
+	eap = (eap_mschapv2_header_t*)data.ptr;
+	
+	if (data.len < 3) /* we want at least an error code: E=e */
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: too short");
+		return FAILED;
+	}
+	
+	message_len = data.len - HEADER_LEN;
+	message = malloc(message_len + 1);
+	memcpy(message, eap->data, message_len);
+	message[message_len] = '\0';
+			
+	/* E=eeeeeeeeee R=r C=cccccccccccccccccccccccccccccccc V=vvvvvvvvvv M=<msg> */
+	enumerator = enumerator_create_token(message, " ", " ");
+	while (enumerator->enumerate(enumerator, &token))
+	{
+		if (strneq(token, "E=", 2))
+		{
+			token += 2;
+			error = atoi(token);
+		}
+		else if (strneq(token, "R=", 2))
+		{
+			token += 2;
+			retryable = atoi(token);
+		}
+		else if (strneq(token, "C=", 2))
+		{
+			chunk_t hex;
+			token += 2;
+			if (strlen(token) != 2 * CHALLENGE_LEN)
+			{
+				DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: invalid challenge");
+				goto error;
+			}
+			hex = chunk_create(token, 2 * CHALLENGE_LEN);
+			challenge = chunk_from_hex(hex, NULL);
+		}
+		else if (strneq(token, "V=", 2))
+		{
+			int version;
+			token += 2;
+			version = atoi(token);
+		}
+		else if (strneq(token, "M=", 2))
+		{
+			token += 2;
+			msg = strdup(token);
+		}
+	}
+	enumerator->destroy(enumerator);
+			
+	DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed with error %N: '%s'", mschapv2_error_names, error, msg);
+			
+	/**
+	 * at this point, if the error is retryable, we MAY retry the
+	 * authentication or MAY send a Change Password packet.
+	 * 
+	 * if the error is not retryable (or if we do neither of the
+	 * above), we SHOULD send a Failure Response packet.
+	 * windows clients don't do that, and since windows server 2008 r2
+	 * behaves pretty odd if we do send a Failure Response, we just
+	 * don't send one either.
+	 * 
+	 * btw, windows server 2008 r2 does not send non-retryable errors
+	 * for e.g. a disabled account but returns the windows error code in
+	 * a notify payload of type 12345.
+	 */
+	
+	status = FAILED;
+	
+error:
+	chunk_free(&challenge);
+	free(message);
+	free(msg);
+	return status;
+}
+
+/**
+ * Implementation of eap_method_t.process for the peer
+ */
+static status_t process_peer(private_eap_mschapv2_t *this, eap_payload_t *in,
+		eap_payload_t **out)
+{
+	chunk_t data;
+	eap_mschapv2_header_t *eap;
+	
+	this->identifier = in->get_identifier(in);
+	data = in->get_data(in);
+	if (data.len < SHORT_HEADER_LEN)
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message");
+		return FAILED;
+	}
+	
+	eap = (eap_mschapv2_header_t*)data.ptr;
+		
+	switch (eap->opcode)
+	{
+		case MSCHAPV2_CHALLENGE:
+		{
+			return process_peer_challenge(this, in, out);
+		}
+		case MSCHAPV2_SUCCESS:
+		{
+			return process_peer_success(this, in, out);
+		}
+		case MSCHAPV2_FAILURE:
+		{
+			return process_peer_failure(this, in, out);
+		}
+		default:
+		{
+			DBG1(DBG_IKE, "EAP-MS-CHAPv2 received packet with unsupported OpCode (%N)!",
+					mschapv2_opcode_names, eap->opcode);
+			break;
+		}
+	}
+	return FAILED;
+}
+
+/**
+ * Handles retries on the server
+ */
+static status_t process_server_retry(private_eap_mschapv2_t *this,
+									 eap_payload_t **out)
+{
+	eap_mschapv2_header_t *eap;
+	rng_t *rng;
+	chunk_t hex;
+	char msg[FAILURE_MESSAGE_LEN];
+	u_int16_t len = HEADER_LEN + FAILURE_MESSAGE_LEN - 1;
+	
+	if (++this->retries > MAX_RETRIES)
+	{
+		/* we MAY send a Failure Request with R=0, but windows 7 does not
+		 * really like that and does not respond with a Failure Response.
+		 * so, to clean up our state we just fail with an EAP-Failure.
+		 * this gives an unknown error on the windows side, but is also fine
+		 * with the standard. */
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 verification failed: maximum number of retries reached");
+		return FAILED;
+	}
+	
+	DBG1(DBG_IKE, "EAP-MS-CHAPv2 verification failed, retry (%d)", this->retries);
+	
+	rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+	if (!rng)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 failed, no RNG");
+		return FAILED;
+	}
+	rng->get_bytes(rng, CHALLENGE_LEN, this->challenge.ptr);
+	rng->destroy(rng);
+	
+	eap = alloca(len);
+	eap->code = EAP_REQUEST;
+	eap->identifier = ++this->identifier;
+	eap->length = htons(len);
+	eap->type = EAP_MSCHAPV2;
+	eap->opcode = MSCHAPV2_FAILURE;
+	eap->ms_chapv2_id = this->mschapv2id++; /* increase for each retry */
+	eap->ms_length = htons(len - 5);
+	
+	hex = chunk_to_hex(this->challenge, NULL, TRUE);
+	snprintf(msg, FAILURE_MESSAGE_LEN, "%s%s", FAILURE_MESSAGE, hex.ptr);
+	chunk_free(&hex);
+	memcpy(eap->data, msg, FAILURE_MESSAGE_LEN - 1);
+	*out = eap_payload_create_data(chunk_create((void*) eap, len));
+	
+	/* delay the response for some time to make brute-force attacks harder */
+	sleep(RETRY_DELAY);
+	
+	return NEED_MORE;
+}
+
+/**
+ * Process MS-CHAPv2 Response response packets
+ */
+static status_t process_server_response(private_eap_mschapv2_t *this,
+										eap_payload_t *in, eap_payload_t **out)
+{
+	eap_mschapv2_header_t *eap;
+	eap_mschapv2_response_t *res;
+	chunk_t data, peer_challenge, username, password;
+	identification_t *userid;
+	shared_key_t *shared;
+	int name_len;
+	
+	data = in->get_data(in);
+	eap = (eap_mschapv2_header_t*)data.ptr;
+	
+	if (data.len < RESPONSE_PAYLOAD_LEN)
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: too short");
+		return FAILED;
+	}
+	
+	res = (eap_mschapv2_response_t*)eap->data;
+	peer_challenge = chunk_create(res->response.peer_challenge, CHALLENGE_LEN);
+	
+	name_len = min(data.len - RESPONSE_PAYLOAD_LEN, 255);
+	userid = identification_create_from_encoding(ID_EAP,
+												 chunk_create(res->name, name_len));
+	username = extract_username(userid);
+	DBG2(DBG_IKE, "EAP-MS-CHAPv2 username: '%.*s'", name_len, res->name);
+	
+	shared = charon->credentials->get_shared(charon->credentials,
+											 SHARED_EAP, this->server, userid);
+	if (shared == NULL)
+	{
+		DBG1(DBG_IKE, "no EAP key found for hosts '%D' - '%D'",
+					  this->server, userid);
+		/* FIXME: windows 7 always sends the username that is first entered in
+		 * the username box, even, if the user changes it during retries (probably
+		 * to keep consistent with the EAP-Identity).
+	 	 * thus, we could actually fail here, because retries do not make much
+	 	 * sense. on the other hand, an attacker could guess usernames, if the
+	 	 * error messages were different. */
+		return process_server_retry(this, out);
+	}
+	
+	password = ascii_to_unicode(shared->get_key(shared));
+	shared->destroy(shared);
+	
+	if (GenerateStuff(this, this->challenge, peer_challenge, username, password) != SUCCESS)
+	{
+		DBG1(DBG_IKE, "EAP-MS-CHAPv2 verification failed");	
+		chunk_clear(&password);
+		return FAILED;
+	}
+	chunk_clear(&password);
+	
+	if (memeq(res->response.nt_response, this->nt_response.ptr, this->nt_response.len))
+	{
+		chunk_t hex;
+		char msg[AUTH_RESPONSE_LEN + sizeof(SUCCESS_MESSAGE)];
+		u_int16_t len = HEADER_LEN + AUTH_RESPONSE_LEN + sizeof(SUCCESS_MESSAGE);
+		
+		eap = alloca(len);
+		eap->code = EAP_REQUEST;
+		eap->identifier = ++this->identifier;
+		eap->length = htons(len);
+		eap->type = EAP_MSCHAPV2;
+		eap->opcode = MSCHAPV2_SUCCESS;
+		eap->ms_chapv2_id = this->mschapv2id;
+		eap->ms_length = htons(len - 5);
+		
+		hex = chunk_to_hex(this->auth_response, NULL, TRUE);
+		snprintf(msg, AUTH_RESPONSE_LEN + sizeof(SUCCESS_MESSAGE),
+					  "S=%s%s", hex.ptr, SUCCESS_MESSAGE);
+		chunk_free(&hex);
+		memcpy(eap->data, msg, AUTH_RESPONSE_LEN + sizeof(SUCCESS_MESSAGE));
+		*out = eap_payload_create_data(chunk_create((void*) eap, len));
+		return NEED_MORE;
+	}
+
+	return process_server_retry(this, out);
+}
+
+/**
+ * Implementation of eap_method_t.process for the server
+ */
+static status_t process_server(private_eap_mschapv2_t *this, eap_payload_t *in,
+		eap_payload_t **out)
+{
+	eap_mschapv2_header_t *eap;
+	chunk_t data;
+	
+	if (this->identifier != in->get_identifier(in))
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: unexpected identifier");
+		return FAILED;
+	}
+	
+	data = in->get_data(in);
+	if (data.len < SHORT_HEADER_LEN)
+	{
+		DBG1(DBG_IKE, "received invalid EAP-MS-CHAPv2 message: too short");
+		return FAILED;
+	}
+	
+	eap = (eap_mschapv2_header_t*)data.ptr;
+	
+	switch (eap->opcode)
+	{
+		case MSCHAPV2_RESPONSE:
+		{
+			return process_server_response(this, in, out);
+		}
+		case MSCHAPV2_SUCCESS:
+		{
+			return SUCCESS;
+		}
+		case MSCHAPV2_FAILURE:
+		{
+			return FAILED;
+		}
+		default:
+		{
+			DBG1(DBG_IKE, "EAP-MS-CHAPv2 received packet with unsupported OpCode (%N)!",
+					mschapv2_opcode_names, eap->opcode);
+			break;
+		}
+	}
+	return FAILED;
+}
+
+/**
+ * Implementation of eap_method_t.get_type.
+ */
+static eap_type_t get_type(private_eap_mschapv2_t *this, u_int32_t *vendor)
+{
+	*vendor = 0;
+	return EAP_MSCHAPV2;
+}
+
+/**
+ * Implementation of eap_method_t.get_msk.
+ */
+static status_t get_msk(private_eap_mschapv2_t *this, chunk_t *msk)
+{
+	if (this->msk.ptr)
+	{
+		*msk = this->msk;
+		return SUCCESS;
+	}
+	return FAILED;
+}
+
+/**
+ * Implementation of eap_method_t.is_mutual.
+ */
+static bool is_mutual(private_eap_mschapv2_t *this)
+{
+	return TRUE;
+}
+
+/**
+ * Implementation of eap_method_t.destroy.
+ */
+static void destroy(private_eap_mschapv2_t *this)
+{
+	this->peer->destroy(this->peer);
+	this->server->destroy(this->server);
+	chunk_free(&this->challenge);
+	chunk_free(&this->nt_response);
+	chunk_free(&this->auth_response);
+	chunk_free(&this->msk);
+	free(this);
+}
+
+/**
+ * Generic constructor
+ */
+static private_eap_mschapv2_t *eap_mschapv2_create_generic(identification_t *server, identification_t *peer)
+{
+	private_eap_mschapv2_t *this = malloc_thing(private_eap_mschapv2_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->nt_response = chunk_empty;
+	this->auth_response = chunk_empty;
+	this->msk = chunk_empty;
+	this->identifier = 0;
+	this->mschapv2id = 0;
+	this->retries = 0;
+	
+	return this;
+}
+
+/*
+ * see header
+ */
+eap_mschapv2_t *eap_mschapv2_create_server(identification_t *server, identification_t *peer)
+{
+	private_eap_mschapv2_t *this = eap_mschapv2_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);
+	
+	this->mschapv2id = this->identifier;
+	
+	return &this->public;
+}
+
+/*
+ * see header
+ */
+eap_mschapv2_t *eap_mschapv2_create_peer(identification_t *server, identification_t *peer)
+{
+	private_eap_mschapv2_t *this = eap_mschapv2_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;
+}
+