Added a counter mode wrapper plugin operating on existing CBC crypters

configure.in

@@ -147,6 +147,7 @@ ARG_ENABL_SET([openssl],        [enables the OpenSSL crypto plugin.])
 ARG_ENABL_SET([gcrypt],         [enables the libgcrypt plugin.])
 ARG_ENABL_SET([agent],          [enables the ssh-agent signing plugin.])
 ARG_ENABL_SET([pkcs11],         [enables the PKCS11 token support plugin.])
+ARG_ENABL_SET([ctr],            [enables the Counter Mode wrapper crypto plugin.])
 ARG_ENABL_SET([addrblock],      [enables RFC 3779 address block constraint support.])
 ARG_ENABL_SET([uci],            [enable OpenWRT UCI configuration plugin.])
 ARG_ENABL_SET([android],        [enable Android specific plugin.])
@@ -714,6 +715,7 @@ ADD_PLUGIN([agent],                [s libcharon])
 ADD_PLUGIN([pkcs11],               [s libcharon pki])
 ADD_PLUGIN([xcbc],                 [s libcharon])
 ADD_PLUGIN([hmac],                 [s libcharon pluto])
+ADD_PLUGIN([ctr],                  [s libcharon])
 ADD_PLUGIN([xauth],                [p pluto])
 ADD_PLUGIN([attr],                 [h libcharon pluto])
 ADD_PLUGIN([attr-sql],             [h libcharon pluto])
@@ -805,6 +807,7 @@ AM_CONDITIONAL(USE_OPENSSL, test x$openssl = xtrue)
 AM_CONDITIONAL(USE_GCRYPT, test x$gcrypt = xtrue)
 AM_CONDITIONAL(USE_AGENT, test x$agent = xtrue)
 AM_CONDITIONAL(USE_PKCS11, test x$pkcs11 = xtrue)
+AM_CONDITIONAL(USE_CTR, test x$ctr = xtrue)
 
 dnl charon plugins
 dnl ==============
@@ -936,6 +939,7 @@ AC_OUTPUT(
 	src/libstrongswan/plugins/gcrypt/Makefile
 	src/libstrongswan/plugins/agent/Makefile
 	src/libstrongswan/plugins/pkcs11/Makefile
+	src/libstrongswan/plugins/ctr/Makefile
 	src/libstrongswan/plugins/test_vectors/Makefile
 	src/libhydra/Makefile
 	src/libhydra/plugins/attr/Makefile

src/libstrongswan/Makefile.am

@@ -323,6 +323,13 @@ if MONOLITHIC
 endif
 endif
 
+if USE_CTR
+  SUBDIRS += plugins/ctr
+if MONOLITHIC
+  libstrongswan_la_LIBADD += plugins/ctr/libstrongswan-ctr.la
+endif
+endif
+
 if USE_TEST_VECTORS
   SUBDIRS += plugins/test_vectors
 if MONOLITHIC

src/libstrongswan/plugins/ctr/Makefile.am

@@ -0,0 +1,16 @@
+
+INCLUDES = -I$(top_srcdir)/src/libstrongswan
+
+AM_CFLAGS = -rdynamic
+
+if MONOLITHIC
+noinst_LTLIBRARIES = libstrongswan-ctr.la
+else
+plugin_LTLIBRARIES = libstrongswan-ctr.la
+endif
+
+libstrongswan_ctr_la_SOURCES = \
+	ctr_plugin.h ctr_plugin.c \
+	ctr_ipsec_crypter.h ctr_ipsec_crypter.c
+
+libstrongswan_ctr_la_LDFLAGS = -module -avoid-version

src/libstrongswan/plugins/ctr/ctr_ipsec_crypter.c

@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * 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 "ctr_ipsec_crypter.h"
+
+typedef struct private_ctr_ipsec_crypter_t private_ctr_ipsec_crypter_t;
+
+/**
+ * Private data of an ctr_ipsec_crypter_t object.
+ */
+struct private_ctr_ipsec_crypter_t {
+
+	/**
+	 * Public ctr_ipsec_crypter_t interface.
+	 */
+	ctr_ipsec_crypter_t public;
+
+	/**
+	 * Underlying CBC crypter
+	 */
+	crypter_t *crypter;
+
+	/**
+	 * counter state
+	 */
+	struct {
+		char nonce[4];
+		char iv[8];
+		u_int32_t counter;
+	} __attribute__((packed)) state;
+};
+
+/**
+ * Do the CTR crypto operation
+ */
+static void crypt_ctr(private_ctr_ipsec_crypter_t *this,
+					  chunk_t in, chunk_t out)
+{
+	size_t is, bs;
+	chunk_t state;
+
+	is = this->crypter->get_iv_size(this->crypter);
+	bs = sizeof(this->state);
+
+	this->state.counter = htonl(1);
+	state = chunk_create((char*)&this->state, bs);
+
+	while (in.len > 0)
+	{
+		char iv[is], block[bs];
+
+		memset(iv, 0, is);
+		memcpy(block, state.ptr, bs);
+		this->crypter->encrypt(this->crypter,
+						chunk_create(block, bs), chunk_create(iv, is), NULL);
+		chunk_increment(state);
+
+		if (in.ptr != out.ptr)
+		{
+			memcpy(out.ptr, in.ptr, min(in.len, bs));
+		}
+		memxor(out.ptr, block, min(in.len, bs));
+		in = chunk_skip(in, bs);
+		out = chunk_skip(out, bs);
+	}
+}
+
+METHOD(crypter_t, crypt, void,
+	private_ctr_ipsec_crypter_t *this, chunk_t in, chunk_t iv, chunk_t *out)
+{
+	memcpy(this->state.iv, iv.ptr, sizeof(this->state.iv));
+
+	if (out)
+	{
+		*out = chunk_alloc(in.len);
+		crypt_ctr(this, in, *out);
+	}
+	else
+	{
+		crypt_ctr(this, in, in);
+	}
+}
+
+METHOD(crypter_t, get_block_size, size_t,
+	private_ctr_ipsec_crypter_t *this)
+{
+	return 1;
+}
+
+METHOD(crypter_t, get_iv_size, size_t,
+	private_ctr_ipsec_crypter_t *this)
+{
+	return sizeof(this->state.iv);
+}
+
+METHOD(crypter_t, get_key_size, size_t,
+	private_ctr_ipsec_crypter_t *this)
+{
+	return this->crypter->get_key_size(this->crypter)
+			+ sizeof(this->state.nonce);
+}
+
+METHOD(crypter_t, set_key, void,
+	private_ctr_ipsec_crypter_t *this, chunk_t key)
+{
+	memcpy(this->state.nonce, key.ptr + key.len - sizeof(this->state.nonce),
+		   sizeof(this->state.nonce));
+	key.len -= sizeof(this->state.nonce);
+	this->crypter->set_key(this->crypter, key);
+}
+
+METHOD(crypter_t, destroy, void,
+	private_ctr_ipsec_crypter_t *this)
+{
+	this->crypter->destroy(this->crypter);
+	free(this);
+}
+
+/**
+ * See header
+ */
+ctr_ipsec_crypter_t *ctr_ipsec_crypter_create(encryption_algorithm_t algo,
+											  size_t key_size)
+{
+	private_ctr_ipsec_crypter_t *this;
+
+	switch (algo)
+	{
+		case ENCR_AES_CTR:
+			algo = ENCR_AES_CBC;
+			break;
+		case ENCR_CAMELLIA_CTR:
+			algo = ENCR_CAMELLIA_CBC;
+			break;
+		default:
+			return NULL;
+	}
+
+	INIT(this,
+		.public.crypter = {
+			.encrypt = _crypt,
+			.decrypt = _crypt,
+			.get_block_size = _get_block_size,
+			.get_iv_size = _get_iv_size,
+			.get_key_size = _get_key_size,
+			.set_key = _set_key,
+			.destroy = _destroy,
+		},
+		.crypter = lib->crypto->create_crypter(lib->crypto, algo, key_size),
+	);
+
+	if (!this->crypter)
+	{
+		free(this);
+		return NULL;
+	}
+
+	return &this->public;
+}

src/libstrongswan/plugins/ctr/ctr_ipsec_crypter.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * 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.
+ */
+
+/**
+ * @defgroup ctr_ipsec_crypter ctr_ipsec_crypter
+ * @{ @ingroup ctr
+ */
+
+#ifndef CTR_IPSEC_CRYPTER_H_
+#define CTR_IPSEC_CRYPTER_H_
+
+#include <crypto/crypters/crypter.h>
+
+typedef struct ctr_ipsec_crypter_t ctr_ipsec_crypter_t;
+
+/**
+ * Counter Mode wrapper for encryption algorithms, IPsec variant (RFC3686).
+ */
+struct ctr_ipsec_crypter_t {
+
+	/**
+	 * Implements crypter_t interface.
+	 */
+	crypter_t crypter;
+};
+
+/**
+ * Create a ctr_ipsec_crypter instance.
+ */
+ctr_ipsec_crypter_t *ctr_ipsec_crypter_create();
+
+/**
+ * Create a ctr_ipsec_crypter instance.
+ *
+ * @param key_size		key size in bytes
+ * @param algo			algorithm to implement, a counter mode
+ * @return				crypter, NULL if not supported
+ */
+ctr_ipsec_crypter_t *ctr_ipsec_crypter_create(encryption_algorithm_t algo,
+											  size_t key_size);
+
+#endif /** CTR_IPSEC_CRYPTER_H_ @}*/

src/libstrongswan/plugins/ctr/ctr_plugin.c

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * 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 "ctr_plugin.h"
+
+#include <library.h>
+
+#include "ctr_ipsec_crypter.h"
+
+typedef struct private_ctr_plugin_t private_ctr_plugin_t;
+
+/**
+ * private data of ctr_plugin
+ */
+struct private_ctr_plugin_t {
+
+	/**
+	 * public functions
+	 */
+	ctr_plugin_t public;
+};
+
+METHOD(plugin_t, destroy, void,
+	private_ctr_plugin_t *this)
+{
+	lib->crypto->remove_crypter(lib->crypto,
+					(crypter_constructor_t)ctr_ipsec_crypter_create);
+
+	free(this);
+}
+
+/*
+ * see header file
+ */
+plugin_t *ctr_plugin_create()
+{
+	private_ctr_plugin_t *this;
+
+	INIT(this,
+		.public.plugin.destroy = _destroy,
+	);
+
+	lib->crypto->add_crypter(lib->crypto, ENCR_AES_CTR,
+					(crypter_constructor_t)ctr_ipsec_crypter_create);
+	lib->crypto->add_crypter(lib->crypto, ENCR_CAMELLIA_CTR,
+					(crypter_constructor_t)ctr_ipsec_crypter_create);
+
+	return &this->public.plugin;
+}

src/libstrongswan/plugins/ctr/ctr_plugin.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2010 Martin Willi
+ * Copyright (C) 2010 revosec AG
+ *
+ * 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.
+ */
+
+/**
+ * @defgroup ctr ctr
+ * @ingroup plugins
+ *
+ * @defgroup ctr_plugin ctr_plugin
+ * @{ @ingroup ctr
+ */
+
+#ifndef CTR_PLUGIN_H_
+#define CTR_PLUGIN_H_
+
+#include <plugins/plugin.h>
+
+typedef struct ctr_plugin_t ctr_plugin_t;
+
+/**
+ * Plugin providing CTR mode operation of symmetric encryption algorithms.
+ */
+struct ctr_plugin_t {
+
+	/**
+	 * Implements plugin interface.
+	 */
+	plugin_t plugin;
+};
+
+#endif /** CTR_PLUGIN_H_ @}*/