Implemented an AEAD wrapper for traditional crypter/signer transforms
authorMartin Willi <martin@revosec.ch>
Tue, 17 Aug 2010 15:26:15 +0000 (17:26 +0200)
committerMartin Willi <martin@revosec.ch>
Thu, 19 Aug 2010 10:35:54 +0000 (12:35 +0200)
src/libstrongswan/Makefile.am
src/libstrongswan/crypto/aead.c [new file with mode: 0644]
src/libstrongswan/crypto/aead.h [new file with mode: 0644]

index 8b6aa8b..e1e33c1 100644 (file)
@@ -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/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 \
 crypto/transform.c crypto/transform.h \
 credentials/credential_factory.c credentials/credential_factory.h \
 credentials/builder.c credentials/builder.h \
diff --git a/src/libstrongswan/crypto/aead.c b/src/libstrongswan/crypto/aead.c
new file mode 100644 (file)
index 0000000..51cb059
--- /dev/null
@@ -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;
+}
diff --git a/src/libstrongswan/crypto/aead.h b/src/libstrongswan/crypto/aead.h
new file mode 100644 (file)
index 0000000..d560381
--- /dev/null
@@ -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_ @}*/