crypto: add block encryption framework

Add a generic framework for supporting different block encryption
formats. Upon instantiating a QCryptoBlock object, it will read
the encryption header and extract the encryption keys. It is
then possible to call methods to encrypt/decrypt data buffers.

There is also a mode whereby it will create/initialize a new
encryption header on a previously unformatted volume.

The initial framework comes with support for the legacy QCow
AES based encryption. This enables code in the QCow driver to
be consolidated later.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

1 files changed, 92 insertions, 0 deletions

diff --git a/crypto/blockpriv.h b/crypto/blockpriv.h
new file mode 100644
index 0000000..6297085
--- /dev/null
+++ b/crypto/blockpriv.h
@@ -0,0 +1,92 @@
+/*
+ * QEMU Crypto block device encryption
+ *
+ * Copyright (c) 2015-2016 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef QCRYPTO_BLOCK_PRIV_H__
+#define QCRYPTO_BLOCK_PRIV_H__
+
+#include "crypto/block.h"
+
+typedef struct QCryptoBlockDriver QCryptoBlockDriver;
+
+struct QCryptoBlock {
+    QCryptoBlockFormat format;
+
+    const QCryptoBlockDriver *driver;
+    void *opaque;
+
+    QCryptoCipher *cipher;
+    QCryptoIVGen *ivgen;
+    QCryptoHashAlgorithm kdfhash;
+    size_t niv;
+    uint64_t payload_offset; /* In bytes */
+};
+
+struct QCryptoBlockDriver {
+    int (*open)(QCryptoBlock *block,
+                QCryptoBlockOpenOptions *options,
+                QCryptoBlockReadFunc readfunc,
+                void *opaque,
+                unsigned int flags,
+                Error **errp);
+
+    int (*create)(QCryptoBlock *block,
+                  QCryptoBlockCreateOptions *options,
+                  QCryptoBlockInitFunc initfunc,
+                  QCryptoBlockWriteFunc writefunc,
+                  void *opaque,
+                  Error **errp);
+
+    void (*cleanup)(QCryptoBlock *block);
+
+    int (*encrypt)(QCryptoBlock *block,
+                   uint64_t startsector,
+                   uint8_t *buf,
+                   size_t len,
+                   Error **errp);
+    int (*decrypt)(QCryptoBlock *block,
+                   uint64_t startsector,
+                   uint8_t *buf,
+                   size_t len,
+                   Error **errp);
+
+    bool (*has_format)(const uint8_t *buf,
+                       size_t buflen);
+};
+
+
+int qcrypto_block_decrypt_helper(QCryptoCipher *cipher,
+                                 size_t niv,
+                                 QCryptoIVGen *ivgen,
+                                 int sectorsize,
+                                 uint64_t startsector,
+                                 uint8_t *buf,
+                                 size_t len,
+                                 Error **errp);
+
+int qcrypto_block_encrypt_helper(QCryptoCipher *cipher,
+                                 size_t niv,
+                                 QCryptoIVGen *ivgen,
+                                 int sectorsize,
+                                 uint64_t startsector,
+                                 uint8_t *buf,
+                                 size_t len,
+                                 Error **errp);
+
+#endif /* QCRYPTO_BLOCK_PRIV_H__ */