[RFC,v2,3/5] crypto/secret: add secret class files.

diff --git a/crypto/secret.c b/crypto/secret.c
new file mode 100644
index 0000000000..d9be0409e4
--- /dev/null
+++ b/crypto/secret.c
@@ -0,0 +1,167 @@ 
+/*
+ * QEMU crypto secret support
+ *
+ * Copyright (c) 2015 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 2.1 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/secret.h"
+#include "qapi/error.h"
+#include "qom/object_interfaces.h"
+#include "qemu/module.h"
+#include "trace.h"
+
+
+static void
+qcrypto_secret_load_data(Object *obj,
+                         uint8_t **output,
+                         size_t *outputlen,
+                         Error **errp)
+{
+    char *data = NULL;
+    size_t length = 0;
+    GError *gerr = NULL;
+
+    QCryptoSecret *secret = QCRYPTO_SECRET(obj);
+
+    *output = NULL;
+    *outputlen = 0;
+
+    if (secret->file) {
+        if (secret->data) {
+            error_setg(errp,
+                       "'file' and 'data' are mutually exclusive");
+            return;
+        }
+        if (!g_file_get_contents(secret->file, &data, &length, &gerr)) {
+            error_setg(errp,
+                       "Unable to read %s: %s",
+                       secret->file, gerr->message);
+            g_error_free(gerr);
+            return;
+        }
+        *output = (uint8_t *)data;
+        *outputlen = length;
+    } else if (secret->data) {
+        *outputlen = strlen(secret->data);
+        *output = (uint8_t *)g_strdup(secret->data);
+    } else {
+        error_setg(errp, "Either 'file' or 'data' must be provided");
+    }
+}
+
+
+static void
+qcrypto_secret_prop_set_data(Object *obj,
+                             const char *value,
+                             Error **errp)
+{
+    QCryptoSecret *secret = QCRYPTO_SECRET(obj);
+
+    g_free(secret->data);
+    secret->data = g_strdup(value);
+}
+
+
+static char *
+qcrypto_secret_prop_get_data(Object *obj,
+                             Error **errp)
+{
+    QCryptoSecret *secret = QCRYPTO_SECRET(obj);
+    return g_strdup(secret->data);
+}
+
+
+static void
+qcrypto_secret_prop_set_file(Object *obj,
+                             const char *value,
+                             Error **errp)
+{
+    QCryptoSecret *secret = QCRYPTO_SECRET(obj);
+
+    g_free(secret->file);
+    secret->file = g_strdup(value);
+}
+
+
+static char *
+qcrypto_secret_prop_get_file(Object *obj,
+                             Error **errp)
+{
+    QCryptoSecret *secret = QCRYPTO_SECRET(obj);
+    return g_strdup(secret->file);
+}
+
+
+static void
+qcrypto_secret_complete(UserCreatable *uc, Error **errp)
+{
+    object_property_set_bool(OBJECT(uc), true, "loaded", errp);
+}
+
+
+static void
+qcrypto_secret_finalize(Object *obj)
+{
+    QCryptoSecret *secret = QCRYPTO_SECRET(obj);
+
+    g_free(secret->file);
+    g_free(secret->data);
+}
+
+static void
+qcrypto_secret_class_init(ObjectClass *oc, void *data)
+{
+    QCryptoSecretCommonClass *sic = QCRYPTO_SECRET_COMMON_CLASS(oc);
+    sic->load_data = qcrypto_secret_load_data;
+
+    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
+    ucc->complete = qcrypto_secret_complete;
+
+    object_class_property_add_str(oc, "data",
+                                  qcrypto_secret_prop_get_data,
+                                  qcrypto_secret_prop_set_data,
+                                  NULL);
+    object_class_property_add_str(oc, "file",
+                                  qcrypto_secret_prop_get_file,
+                                  qcrypto_secret_prop_set_file,
+                                  NULL);
+}
+
+
+static const TypeInfo qcrypto_secret_info = {
+    .parent = TYPE_QCRYPTO_SECRET_COMMON,
+    .name = TYPE_QCRYPTO_SECRET,
+    .instance_size = sizeof(QCryptoSecret),
+    .instance_finalize = qcrypto_secret_finalize,
+    .class_size = sizeof(QCryptoSecretClass),
+    .class_init = qcrypto_secret_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_USER_CREATABLE },
+        { }
+    }
+};
+
+
+static void
+qcrypto_secret_register_types(void)
+{
+    type_register_static(&qcrypto_secret_info);
+}
+
+
+type_init(qcrypto_secret_register_types);
diff --git a/include/crypto/secret.h b/include/crypto/secret.h
new file mode 100644
index 0000000000..2ce8dcc24f
--- /dev/null
+++ b/include/crypto/secret.h
@@ -0,0 +1,133 @@ 
+/*
+ * QEMU crypto secret support
+ *
+ * Copyright (c) 2015 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 2.1 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_SECRET_H
+#define QCRYPTO_SECRET_H
+
+#include "qapi/qapi-types-crypto.h"
+#include "qom/object.h"
+#include "crypto/secret_interface.h"
+
+#define TYPE_QCRYPTO_SECRET "secret"
+#define QCRYPTO_SECRET(obj) \
+    OBJECT_CHECK(QCryptoSecret, (obj), TYPE_QCRYPTO_SECRET)
+
+typedef struct QCryptoSecret QCryptoSecret;
+typedef struct QCryptoSecretClass QCryptoSecretClass;
+
+/**
+ * QCryptoSecret:
+ *
+ * The QCryptoSecret object provides storage of secrets,
+ * which may be user passwords, encryption keys or any
+ * other kind of sensitive data that is represented as
+ * a sequence of bytes.
+ *
+ * The sensitive data associated with the secret can
+ * be provided directly via the 'data' property, or
+ * indirectly via the 'file' property. In the latter
+ * case there is support for file descriptor passing
+ * via the usual /dev/fdset/NN syntax that QEMU uses.
+ *
+ * The data for a secret can be provided in two formats,
+ * either as a UTF-8 string (the default), or as base64
+ * encoded 8-bit binary data. The latter is appropriate
+ * for raw encryption keys, while the former is appropriate
+ * for user entered passwords.
+ *
+ * The data may be optionally encrypted with AES-256-CBC,
+ * and the decryption key provided by another
+ * QCryptoSecret instance identified by the 'keyid'
+ * property. When passing sensitive data directly
+ * via the 'data' property it is strongly recommended
+ * to use the AES encryption facility to prevent the
+ * sensitive data being exposed in the process listing
+ * or system log files.
+ *
+ * Providing data directly, insecurely (suitable for
+ * ad hoc developer testing only)
+ *
+ *  $QEMU -object secret,id=sec0,data=letmein
+ *
+ * Providing data indirectly:
+ *
+ *  # printf "letmein" > password.txt
+ *  # $QEMU \
+ *      -object secret,id=sec0,file=password.txt
+ *
+ * Using a master encryption key with data.
+ *
+ * The master key needs to be created as 32 secure
+ * random bytes (optionally base64 encoded)
+ *
+ *  # openssl rand -base64 32 > key.b64
+ *  # KEY=$(base64 -d key.b64 | hexdump  -v -e '/1 "%02X"')
+ *
+ * Each secret to be encrypted needs to have a random
+ * initialization vector generated. These do not need
+ * to be kept secret
+ *
+ *  # openssl rand -base64 16 > iv.b64
+ *  # IV=$(base64 -d iv.b64 | hexdump  -v -e '/1 "%02X"')
+ *
+ * A secret to be defined can now be encrypted
+ *
+ *  # SECRET=$(printf "letmein" |
+ *             openssl enc -aes-256-cbc -a -K $KEY -iv $IV)
+ *
+ * When launching QEMU, create a master secret pointing
+ * to key.b64 and specify that to be used to decrypt
+ * the user password
+ *
+ *  # $QEMU \
+ *      -object secret,id=secmaster0,format=base64,file=key.b64 \
+ *      -object secret,id=sec0,keyid=secmaster0,format=base64,\
+ *          data=$SECRET,iv=$(<iv.b64)
+ *
+ * When encrypting, the data can still be provided via an
+ * external file, in which case it is possible to use either
+ * raw binary data, or base64 encoded. This example uses
+ * raw format
+ *
+ *  # printf "letmein" |
+ *       openssl enc -aes-256-cbc -K $KEY -iv $IV -o pw.aes
+ *  # $QEMU \
+ *      -object secret,id=secmaster0,format=base64,file=key.b64 \
+ *      -object secret,id=sec0,keyid=secmaster0,\
+ *          file=pw.aes,iv=$(<iv.b64)
+ *
+ * Note that the ciphertext can be in either raw or base64
+ * format, as indicated by the 'format' parameter, but the
+ * plaintext resulting from decryption is expected to always
+ * be in raw format.
+ */
+
+struct QCryptoSecret {
+    QCryptoSecretCommon parent_obj;
+    char *data;
+    char *file;
+};
+
+
+struct QCryptoSecretClass {
+    QCryptoSecretCommonClass parent_class;
+};
+
+#endif /* QCRYPTO_SECRET_H */