Implemented an AEAD wrapper for traditional crypter/signer transforms

src/libstrongswan/Makefile.am

@@ -21,6 +21,7 @@ crypto/signers/signer.c crypto/signers/signer.h \
 crypto/crypto_factory.c crypto/crypto_factory.h \
 crypto/crypto_tester.c crypto/crypto_tester.h \
 crypto/diffie_hellman.c crypto/diffie_hellman.h \
+crypto/aead.c crypto/aead.h \
 crypto/transform.c crypto/transform.h \
 credentials/credential_factory.c credentials/credential_factory.h \
 credentials/builder.c credentials/builder.h \

src/libstrongswan/crypto/aead.c

@@ -0,0 +1,162 @@
+/*
+ * 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 "aead.h"
+
+#include <debug.h>
+
+typedef struct private_aead_t private_aead_t;
+
+/**
+ * Private data of an aead_t object.
+ */
+struct private_aead_t {
+
+	/**
+	 * Public aead_t interface.
+	 */
+	aead_t public;
+
+	/**
+	 * traditional crypter
+	 */
+	crypter_t *crypter;
+
+	/**
+	 * draditional signer
+	 */
+	signer_t *signer;
+};
+
+METHOD(aead_t, encrypt, void,
+	private_aead_t *this, chunk_t plain, chunk_t assoc, chunk_t iv,
+	chunk_t *encrypted)
+{
+	chunk_t encr, sig;
+
+	this->signer->get_signature(this->signer, assoc, NULL);
+	this->signer->get_signature(this->signer, iv, NULL);
+
+	if (encrypted)
+	{
+		this->crypter->encrypt(this->crypter, plain, iv, &encr);
+		this->signer->allocate_signature(this->signer, encr, &sig);
+		*encrypted = chunk_cat("cmm", iv, encr, sig);
+	}
+	else
+	{
+		this->crypter->encrypt(this->crypter, plain, iv, NULL);
+		this->signer->get_signature(this->signer, plain, plain.ptr + plain.len);
+	}
+}
+
+METHOD(aead_t, decrypt, bool,
+	private_aead_t *this, chunk_t encrypted, chunk_t assoc, chunk_t iv,
+	chunk_t *plain)
+{
+	chunk_t sig;
+	size_t bs;
+
+	bs = this->crypter->get_block_size(this->crypter);
+	sig.len = this->signer->get_block_size(this->signer);
+	if (sig.len > encrypted.len || (encrypted.len - sig.len) % bs)
+	{
+		DBG1(DBG_LIB, "invalid encrypted data length %d with block size %d",
+			encrypted.len - sig.len, bs);
+		return FALSE;
+	}
+	chunk_split(encrypted, "mm", encrypted.len - sig.len,
+				&encrypted, sig.len, &sig);
+
+	this->signer->get_signature(this->signer, assoc, NULL);
+	this->signer->get_signature(this->signer, iv, NULL);
+	if (!this->signer->verify_signature(this->signer, encrypted, sig))
+	{
+		DBG1(DBG_LIB, "MAC verification failed");
+		return FALSE;
+	}
+	this->crypter->decrypt(this->crypter, encrypted, iv, plain);
+	return TRUE;
+}
+
+METHOD(aead_t, get_block_size, size_t,
+	private_aead_t *this)
+{
+	return this->crypter->get_block_size(this->crypter);
+}
+
+METHOD(aead_t, get_icv_size, size_t,
+	private_aead_t *this)
+{
+	return this->signer->get_block_size(this->signer);
+}
+
+METHOD(aead_t, get_iv_size, size_t,
+	private_aead_t *this)
+{
+	return this->crypter->get_iv_size(this->crypter);
+}
+
+METHOD(aead_t, get_key_size, size_t,
+	private_aead_t *this)
+{
+	return this->crypter->get_key_size(this->crypter) +
+			this->signer->get_key_size(this->signer);
+}
+
+METHOD(aead_t, set_key, void,
+	private_aead_t *this, chunk_t key)
+{
+	chunk_t sig, enc;
+
+	chunk_split(key, "mm", this->signer->get_key_size(this->signer), &sig,
+				this->crypter->get_key_size(this->crypter), &enc);
+
+	this->signer->set_key(this->signer, sig);
+	this->crypter->set_key(this->crypter, enc);
+}
+
+METHOD(aead_t, destroy, void,
+	private_aead_t *this)
+{
+	this->crypter->destroy(this->crypter);
+	this->signer->destroy(this->signer);
+	free(this);
+}
+
+/**
+ * See header
+ */
+aead_t *aead_create(crypter_t *crypter, signer_t *signer)
+{
+	private_aead_t *this;
+
+	INIT(this,
+		.public = {
+			.encrypt = _encrypt,
+			.decrypt = _decrypt,
+			.get_block_size = _get_block_size,
+			.get_icv_size = _get_icv_size,
+			.get_iv_size = _get_iv_size,
+			.get_key_size = _get_key_size,
+			.set_key = _set_key,
+			.destroy = _destroy,
+		},
+		.crypter = crypter,
+		.signer = signer,
+	);
+
+	return &this->public;
+}

src/libstrongswan/crypto/aead.h

@@ -0,0 +1,119 @@
+/*
+ * 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 aead aead
+ * @{ @ingroup crypto
+ */
+
+#ifndef AEAD_H_
+#define AEAD_H_
+
+typedef struct aead_t aead_t;
+
+#include <library.h>
+#include <crypto/crypters/crypter.h>
+#include <crypto/signers/signer.h>
+
+/**
+ * Authenticated encryption / authentication decryption interface.
+ */
+struct aead_t {
+
+	/**
+	 * Encrypt and sign data, sign associated data.
+	 *
+	 * The plain data must be a multiple of get_block_size(), the IV must
+	 * have a length of get_iv_size().
+	 * If encrypted is NULL, the encryption is done inline. The buffer must
+	 * have space for additional get_icv_size() data, the ICV value is
+	 * appended silently to the plain chunk.
+	 *
+	 * @param plain			data to encrypt and sign
+	 * @param assoc			associated data to sign
+	 * @param iv			initialization vector
+	 * @param encrypted		allocated encryption result
+	 */
+	void (*encrypt)(aead_t *this, chunk_t plain, chunk_t assoc, chunk_t iv,
+					chunk_t *encrypted);
+
+	/**
+	 * Decrypt and verify data, verify associated data.
+	 *
+	 * The IV must have a length of get_iv_size().
+	 * If plain is NULL, the decryption is done inline. The decrypted data
+	 * is returned in the encrypted chunk, the last get_icv_size() bytes
+	 * contain the verified ICV.
+	 *
+	 * @param encrypted		data to encrypt and verify
+	 * @param assoc			associated data to verify
+	 * @param iv			initialization vector
+	 * @param plain			allocated result, if successful
+	 * @return				TRUE if MAC verification successful
+	 */
+	bool (*decrypt)(aead_t *this, chunk_t encrypted, chunk_t assoc, chunk_t iv,
+					chunk_t *plain);
+
+	/**
+	 * Get the block size for encryption.
+	 *
+	 * @return				block size in bytes
+	 */
+	size_t (*get_block_size)(aead_t *this);
+
+	/**
+	 * Get the integrity check value size of the algorithm.
+	 *
+	 * @return				ICV size in bytes
+	 */
+	size_t (*get_icv_size)(aead_t *this);
+
+	/**
+	 * Get the size of the initialization vector.
+	 *
+	 * @return				IV size in bytes
+	 */
+	size_t (*get_iv_size)(aead_t *this);
+
+	/**
+	 * Get the size of the key material (for encryption and authentication).
+	 *
+	 * @return				key size in bytes
+	 */
+	size_t (*get_key_size)(aead_t *this);
+
+	/**
+	 * Set the key for encryption and authentication.
+	 *
+	 * @param key			encryption and authentication key
+	 */
+	void (*set_key)(aead_t *this, chunk_t key);
+
+	/**
+	 * Destroy a aead_t.
+	 */
+	void (*destroy)(aead_t *this);
+};
+
+/**
+ * Create a aead instance using traditional transforms.
+ *
+ * @param crypter		encryption transform for this aead
+ * @param signer		integrity tranform for this aead
+ * @return				aead transform
+ */
+aead_t *aead_create(crypter_t *crypter, signer_t *signer);
+
+#endif /** AEAD_H_ @}*/