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>
diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs
index 7122cc8..f28b00e 100644
--- a/crypto/Makefile.objs
+++ b/crypto/Makefile.objs
@@ -13,6 +13,10 @@
crypto-obj-y += pbkdf.o
crypto-obj-$(CONFIG_NETTLE) += pbkdf-nettle.o
crypto-obj-$(if $(CONFIG_NETTLE),n,$(CONFIG_GCRYPT_KDF)) += pbkdf-gcrypt.o
+crypto-obj-y += ivgen.o
+crypto-obj-y += ivgen-essiv.o
+crypto-obj-y += ivgen-plain.o
+crypto-obj-y += ivgen-plain64.o
# Let the userspace emulators avoid linking gnutls/etc
crypto-aes-obj-y = aes.o
diff --git a/crypto/ivgen-essiv.c b/crypto/ivgen-essiv.c
new file mode 100644
index 0000000..5649c01
--- /dev/null
+++ b/crypto/ivgen-essiv.c
@@ -0,0 +1,118 @@
+/*
+ * QEMU Crypto block IV generator - essiv
+ *
+ * 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/ivgen-essiv.h"
+
+typedef struct QCryptoIVGenESSIV QCryptoIVGenESSIV;
+struct QCryptoIVGenESSIV {
+ QCryptoCipher *cipher;
+};
+
+static int qcrypto_ivgen_essiv_init(QCryptoIVGen *ivgen,
+ const uint8_t *key, size_t nkey,
+ Error **errp)
+{
+ uint8_t *salt;
+ size_t nhash;
+ size_t nsalt;
+ QCryptoIVGenESSIV *essiv = g_new0(QCryptoIVGenESSIV, 1);
+
+ /* Not necessarily the same as nkey */
+ nsalt = qcrypto_cipher_get_key_len(ivgen->cipher);
+
+ nhash = qcrypto_hash_digest_len(ivgen->hash);
+ /* Salt must be larger of hash size or key size */
+ salt = g_new0(uint8_t, MAX(nhash, nsalt));
+
+ if (qcrypto_hash_bytes(ivgen->hash, (const gchar *)key, nkey,
+ &salt, &nhash,
+ errp) < 0) {
+ g_free(essiv);
+ return -1;
+ }
+
+ /* Now potentially truncate salt to match cipher key len */
+ essiv->cipher = qcrypto_cipher_new(ivgen->cipher,
+ QCRYPTO_CIPHER_MODE_ECB,
+ salt, MIN(nhash, nsalt),
+ errp);
+ if (!essiv->cipher) {
+ g_free(essiv);
+ g_free(salt);
+ return -1;
+ }
+
+ g_free(salt);
+ ivgen->private = essiv;
+
+ return 0;
+}
+
+static int qcrypto_ivgen_essiv_calculate(QCryptoIVGen *ivgen,
+ uint64_t sector,
+ uint8_t *iv, size_t niv,
+ Error **errp)
+{
+ QCryptoIVGenESSIV *essiv = ivgen->private;
+ size_t ndata = qcrypto_cipher_get_block_len(ivgen->cipher);
+ uint8_t *data = g_new(uint8_t, ndata);
+
+ sector = cpu_to_le64(sector);
+ memcpy(data, (uint8_t *)§or, ndata);
+ if (sizeof(sector) < ndata) {
+ memset(data + sizeof(sector), 0, ndata - sizeof(sector));
+ }
+
+ if (qcrypto_cipher_encrypt(essiv->cipher,
+ data,
+ data,
+ ndata,
+ errp) < 0) {
+ g_free(data);
+ return -1;
+ }
+
+ if (ndata > niv) {
+ ndata = niv;
+ }
+ memcpy(iv, data, ndata);
+ if (ndata < niv) {
+ memset(iv + ndata, 0, niv - ndata);
+ }
+ g_free(data);
+ return 0;
+}
+
+static void qcrypto_ivgen_essiv_cleanup(QCryptoIVGen *ivgen)
+{
+ QCryptoIVGenESSIV *essiv = ivgen->private;
+
+ qcrypto_cipher_free(essiv->cipher);
+ g_free(essiv);
+}
+
+
+struct QCryptoIVGenDriver qcrypto_ivgen_essiv = {
+ .init = qcrypto_ivgen_essiv_init,
+ .calculate = qcrypto_ivgen_essiv_calculate,
+ .cleanup = qcrypto_ivgen_essiv_cleanup,
+};
+
diff --git a/crypto/ivgen-essiv.h b/crypto/ivgen-essiv.h
new file mode 100644
index 0000000..4a00af8
--- /dev/null
+++ b/crypto/ivgen-essiv.h
@@ -0,0 +1,28 @@
+/*
+ * QEMU Crypto block IV generator - essiv
+ *
+ * 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 "crypto/ivgenpriv.h"
+
+#ifndef QCRYPTO_IVGEN_ESSIV_H__
+#define QCRYPTO_IVGEN_ESSIV_H__
+
+extern struct QCryptoIVGenDriver qcrypto_ivgen_essiv;
+
+#endif /* QCRYPTO_IVGEN_ESSIV_H__ */
diff --git a/crypto/ivgen-plain.c b/crypto/ivgen-plain.c
new file mode 100644
index 0000000..6a85256
--- /dev/null
+++ b/crypto/ivgen-plain.c
@@ -0,0 +1,59 @@
+/*
+ * QEMU Crypto block IV generator - plain
+ *
+ * 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/ivgen-plain.h"
+
+static int qcrypto_ivgen_plain_init(QCryptoIVGen *ivgen,
+ const uint8_t *key, size_t nkey,
+ Error **errp)
+{
+ return 0;
+}
+
+static int qcrypto_ivgen_plain_calculate(QCryptoIVGen *ivgen,
+ uint64_t sector,
+ uint8_t *iv, size_t niv,
+ Error **errp)
+{
+ size_t ivprefix;
+ uint32_t shortsector = cpu_to_le32((sector & 0xffffffff));
+ ivprefix = sizeof(shortsector);
+ if (ivprefix > niv) {
+ ivprefix = niv;
+ }
+ memcpy(iv, &shortsector, ivprefix);
+ if (ivprefix < niv) {
+ memset(iv + ivprefix, 0, niv - ivprefix);
+ }
+ return 0;
+}
+
+static void qcrypto_ivgen_plain_cleanup(QCryptoIVGen *ivgen)
+{
+}
+
+
+struct QCryptoIVGenDriver qcrypto_ivgen_plain = {
+ .init = qcrypto_ivgen_plain_init,
+ .calculate = qcrypto_ivgen_plain_calculate,
+ .cleanup = qcrypto_ivgen_plain_cleanup,
+};
+
diff --git a/crypto/ivgen-plain.h b/crypto/ivgen-plain.h
new file mode 100644
index 0000000..0fe8835
--- /dev/null
+++ b/crypto/ivgen-plain.h
@@ -0,0 +1,28 @@
+/*
+ * QEMU Crypto block IV generator - plain
+ *
+ * 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 "crypto/ivgenpriv.h"
+
+#ifndef QCRYPTO_IVGEN_PLAIN_H__
+#define QCRYPTO_IVGEN_PLAIN_H__
+
+extern struct QCryptoIVGenDriver qcrypto_ivgen_plain;
+
+#endif /* QCRYPTO_IVGEN_PLAIN_H__ */
diff --git a/crypto/ivgen-plain64.c b/crypto/ivgen-plain64.c
new file mode 100644
index 0000000..9ca6db9
--- /dev/null
+++ b/crypto/ivgen-plain64.c
@@ -0,0 +1,59 @@
+/*
+ * QEMU Crypto block IV generator - plain
+ *
+ * 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/ivgen-plain.h"
+
+static int qcrypto_ivgen_plain_init(QCryptoIVGen *ivgen,
+ const uint8_t *key, size_t nkey,
+ Error **errp)
+{
+ return 0;
+}
+
+static int qcrypto_ivgen_plain_calculate(QCryptoIVGen *ivgen,
+ uint64_t sector,
+ uint8_t *iv, size_t niv,
+ Error **errp)
+{
+ size_t ivprefix;
+ ivprefix = sizeof(sector);
+ sector = cpu_to_le64(sector);
+ if (ivprefix > niv) {
+ ivprefix = niv;
+ }
+ memcpy(iv, §or, ivprefix);
+ if (ivprefix < niv) {
+ memset(iv + ivprefix, 0, niv - ivprefix);
+ }
+ return 0;
+}
+
+static void qcrypto_ivgen_plain_cleanup(QCryptoIVGen *ivgen)
+{
+}
+
+
+struct QCryptoIVGenDriver qcrypto_ivgen_plain64 = {
+ .init = qcrypto_ivgen_plain_init,
+ .calculate = qcrypto_ivgen_plain_calculate,
+ .cleanup = qcrypto_ivgen_plain_cleanup,
+};
+
diff --git a/crypto/ivgen-plain64.h b/crypto/ivgen-plain64.h
new file mode 100644
index 0000000..c410445
--- /dev/null
+++ b/crypto/ivgen-plain64.h
@@ -0,0 +1,28 @@
+/*
+ * QEMU Crypto block IV generator - plain64
+ *
+ * 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 "crypto/ivgenpriv.h"
+
+#ifndef QCRYPTO_IVGEN_PLAIN64_H__
+#define QCRYPTO_IVGEN_PLAIN64_H__
+
+extern struct QCryptoIVGenDriver qcrypto_ivgen_plain64;
+
+#endif /* QCRYPTO_IVGEN_PLAIN64_H__ */
diff --git a/crypto/ivgen.c b/crypto/ivgen.c
new file mode 100644
index 0000000..4ffc1eb
--- /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);
+}
diff --git a/crypto/ivgenpriv.h b/crypto/ivgenpriv.h
new file mode 100644
index 0000000..7b87e02
--- /dev/null
+++ b/crypto/ivgenpriv.h
@@ -0,0 +1,49 @@
+/*
+ * 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/>.
+ *
+ */
+
+#ifndef QCRYPTO_IVGEN_PRIV_H__
+#define QCRYPTO_IVGEN_PRIV_H__
+
+#include "crypto/ivgen.h"
+
+typedef struct QCryptoIVGenDriver QCryptoIVGenDriver;
+
+struct QCryptoIVGenDriver {
+ int (*init)(QCryptoIVGen *ivgen,
+ const uint8_t *key, size_t nkey,
+ Error **errp);
+ int (*calculate)(QCryptoIVGen *ivgen,
+ uint64_t sector,
+ uint8_t *iv, size_t niv,
+ Error **errp);
+ void (*cleanup)(QCryptoIVGen *ivgen);
+};
+
+struct QCryptoIVGen {
+ QCryptoIVGenDriver *driver;
+ void *private;
+
+ QCryptoIVGenAlgorithm algorithm;
+ QCryptoCipherAlgorithm cipher;
+ QCryptoHashAlgorithm hash;
+};
+
+
+#endif /* QCRYPTO_IVGEN_PRIV_H__ */
