crypto: add support for generating initialization vectors

There are a number of different algorithms that can be used
to generate initialization vectors for disk encryption. This
introduces a simple internal QCryptoBlockIV object to provide
a consistent internal API to the different algorithms. The
initially implemented algorithms are 'plain', 'plain64' and
'essiv', each matching the same named algorithm provided
by the Linux kernel dm-crypt driver.

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

1 files changed, 99 insertions, 0 deletions

diff --git a/crypto/ivgen.c b/crypto/ivgen.c
new file mode 100644
index 0000000000..4ffc1eb886
--- /dev/null
+++ b/crypto/ivgen.c
@@ -0,0 +1,99 @@
+/*
+ * QEMU Crypto block IV generator
+ *
+ * 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/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "crypto/ivgenpriv.h"
+#include "crypto/ivgen-plain.h"
+#include "crypto/ivgen-plain64.h"
+#include "crypto/ivgen-essiv.h"
+
+
+QCryptoIVGen *qcrypto_ivgen_new(QCryptoIVGenAlgorithm alg,
+                                QCryptoCipherAlgorithm cipheralg,
+                                QCryptoHashAlgorithm hash,
+                                const uint8_t *key, size_t nkey,
+                                Error **errp)
+{
+    QCryptoIVGen *ivgen = g_new0(QCryptoIVGen, 1);
+
+    ivgen->algorithm = alg;
+    ivgen->cipher = cipheralg;
+    ivgen->hash = hash;
+
+    switch (alg) {
+    case QCRYPTO_IVGEN_ALG_PLAIN:
+        ivgen->driver = &qcrypto_ivgen_plain;
+        break;
+    case QCRYPTO_IVGEN_ALG_PLAIN64:
+        ivgen->driver = &qcrypto_ivgen_plain64;
+        break;
+    case QCRYPTO_IVGEN_ALG_ESSIV:
+        ivgen->driver = &qcrypto_ivgen_essiv;
+        break;
+    default:
+        error_setg(errp, "Unknown block IV generator algorithm %d", alg);
+        g_free(ivgen);
+        return NULL;
+    }
+
+    if (ivgen->driver->init(ivgen, key, nkey, errp) < 0) {
+        g_free(ivgen);
+        return NULL;
+    }
+
+    return ivgen;
+}
+
+
+int qcrypto_ivgen_calculate(QCryptoIVGen *ivgen,
+                            uint64_t sector,
+                            uint8_t *iv, size_t niv,
+                            Error **errp)
+{
+    return ivgen->driver->calculate(ivgen, sector, iv, niv, errp);
+}
+
+
+QCryptoIVGenAlgorithm qcrypto_ivgen_get_algorithm(QCryptoIVGen *ivgen)
+{
+    return ivgen->algorithm;
+}
+
+
+QCryptoCipherAlgorithm qcrypto_ivgen_get_cipher(QCryptoIVGen *ivgen)
+{
+    return ivgen->cipher;
+}
+
+
+QCryptoHashAlgorithm qcrypto_ivgen_get_hash(QCryptoIVGen *ivgen)
+{
+    return ivgen->hash;
+}
+
+
+void qcrypto_ivgen_free(QCryptoIVGen *ivgen)
+{
+    if (!ivgen) {
+        return;
+    }
+    ivgen->driver->cleanup(ivgen);
+    g_free(ivgen);
+}