/*
* 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_common.h"
#include "crypto/cipher.h"
#include "qapi/error.h"
#include "qom/object_interfaces.h"
#include "qemu/base64.h"
#include "qemu/module.h"
#include "trace.h"
static void qcrypto_secret_decrypt(QCryptoSecretCommon *secret,
const uint8_t *input,
size_t inputlen,
uint8_t **output,
size_t *outputlen,
Error **errp)
{
g_autofree uint8_t *iv = NULL;
g_autofree uint8_t *key = NULL;
g_autofree uint8_t *ciphertext = NULL;
size_t keylen, ciphertextlen, ivlen;
g_autoptr(QCryptoCipher) aes = NULL;
g_autofree uint8_t *plaintext = NULL;
*output = NULL;
*outputlen = 0;
if (qcrypto_secret_lookup(secret->keyid,
&key, &keylen,
errp) < 0) {
return;
}
if (keylen != 32) {
error_setg(errp, "Key should be 32 bytes in length");
return;
}
if (!secret->iv) {
error_setg(errp, "IV is required to decrypt secret");
return;
}
iv = qbase64_decode(secret->iv, -1, &ivlen, errp);
if (!iv) {
return;
}
if (ivlen != 16) {
error_setg(errp, "IV should be 16 bytes in length not %zu",
ivlen);
return;
}
aes = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_256,
QCRYPTO_CIPHER_MODE_CBC,
key, keylen,
errp);
if (!aes) {
return;
}
if (qcrypto_cipher_setiv(aes, iv, ivlen, errp) < 0) {
return;
}
if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
ciphertext = qbase64_decode((const gchar *)input,
inputlen,
&ciphertextlen,
errp);
if (!ciphertext) {
return;
}
plaintext = g_new0(uint8_t, ciphertextlen + 1);
} else {
ciphertextlen = inputlen;
plaintext = g_new0(uint8_t, inputlen + 1);
}
if (qcrypto_cipher_decrypt(aes,
ciphertext ? ciphertext : input,
plaintext,
ciphertextlen,
errp) < 0) {
return;
}
if (plaintext[ciphertextlen - 1] > 16 ||
plaintext[ciphertextlen - 1] > ciphertextlen) {
error_setg(errp, "Incorrect number of padding bytes (%d) "
"found on decrypted data",
(int)plaintext[ciphertextlen - 1]);
return;
}
/*
* Even though plaintext may contain arbitrary NUL
* ensure it is explicitly NUL terminated.
*/
ciphertextlen -= plaintext[ciphertextlen - 1];
plaintext[ciphertextlen] = '\0';
*output = g_steal_pointer(&plaintext);
*outputlen = ciphertextlen;
}
static void qcrypto_secret_decode(const uint8_t *input,
size_t inputlen,
uint8_t **output,
size_t *outputlen,
Error **errp)
{
*output = qbase64_decode((const gchar *)input,
inputlen,
outputlen,
errp);
}
static void
qcrypto_secret_prop_set_loaded(Object *obj,
bool value,
Error **errp)
{
QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
QCryptoSecretCommonClass *sec_class
= QCRYPTO_SECRET_COMMON_GET_CLASS(obj);
if (value) {
Error *local_err = NULL;
uint8_t *input = NULL;
size_t inputlen = 0;
uint8_t *output = NULL;
size_t outputlen = 0;
if (sec_class->load_data) {
sec_class->load_data(secret, &input, &inputlen, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
} else {
error_setg(errp, "%s provides no 'load_data' method'",
object_get_typename(obj));
return;
}
if (secret->keyid) {
qcrypto_secret_decrypt(secret, input, inputlen,
&output, &outputlen, &local_err);
g_free(input);
if (local_err) {
error_propagate(errp, local_err);
return;
}
input = output;
inputlen = outputlen;
} else {
if (secret->format == QCRYPTO_SECRET_FORMAT_BASE64) {
qcrypto_secret_decode(input, inputlen,
&output, &outputlen, &local_err);
g_free(input);
if (local_err) {
error_propagate(errp, local_err);
return;
}
input = output;
inputlen = outputlen;
}
}
secret->rawdata = input;
secret->rawlen = inputlen;
} else {
g_free(secret->rawdata);
secret->rawlen = 0;
}
}
static bool
qcrypto_secret_prop_get_loaded(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
return secret->rawdata != NULL;
}
static void
qcrypto_secret_prop_set_format(Object *obj,
int value,
Error **errp G_GNUC_UNUSED)
{
QCryptoSecretCommon *creds = QCRYPTO_SECRET_COMMON(obj);
creds->format = value;
}
static int
qcrypto_secret_prop_get_format(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QCryptoSecretCommon *creds = QCRYPTO_SECRET_COMMON(obj);
return creds->format;
}
static void
qcrypto_secret_prop_set_iv(Object *obj,
const char *value,
Error **errp)
{
QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
g_free(secret->iv);
secret->iv = g_strdup(value);
}
static char *
qcrypto_secret_prop_get_iv(Object *obj,
Error **errp)
{
QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
return g_strdup(secret->iv);
}
static void
qcrypto_secret_prop_set_keyid(Object *obj,
const char *value,
Error **errp)
{
QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
g_free(secret->keyid);
secret->keyid = g_strdup(value);
}
static char *
qcrypto_secret_prop_get_keyid(Object *obj,
Error **errp)
{
QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
return g_strdup(secret->keyid);
}
static void
qcrypto_secret_finalize(Object *obj)
{
QCryptoSecretCommon *secret = QCRYPTO_SECRET_COMMON(obj);
g_free(secret->iv);
g_free(secret->keyid);
g_free(secret->rawdata);
}
static void
qcrypto_secret_class_init(ObjectClass *oc, void *data)
{
object_class_property_add_bool(oc, "loaded",
qcrypto_secret_prop_get_loaded,
qcrypto_secret_prop_set_loaded);
object_class_property_add_enum(oc, "format",
"QCryptoSecretFormat",
&QCryptoSecretFormat_lookup,
qcrypto_secret_prop_get_format,
qcrypto_secret_prop_set_format);
object_class_property_add_str(oc, "keyid",
qcrypto_secret_prop_get_keyid,
qcrypto_secret_prop_set_keyid);
object_class_property_add_str(oc, "iv",
qcrypto_secret_prop_get_iv,
qcrypto_secret_prop_set_iv);
}
int qcrypto_secret_lookup(const char *secretid,
uint8_t **data,
size_t *datalen,
Error **errp)
{
Object *obj;
QCryptoSecretCommon *secret;
obj = object_resolve_path_component(
object_get_objects_root(), secretid);
if (!obj) {
error_setg(errp, "No secret with id '%s'", secretid);
return -1;
}
secret = (QCryptoSecretCommon *)
object_dynamic_cast(obj,
TYPE_QCRYPTO_SECRET_COMMON);
if (!secret) {
error_setg(errp, "Object with id '%s' is not a secret",
secretid);
return -1;
}
if (!secret->rawdata) {
error_setg(errp, "Secret with id '%s' has no data",
secretid);
return -1;
}
*data = g_new0(uint8_t, secret->rawlen + 1);
memcpy(*data, secret->rawdata, secret->rawlen);
(*data)[secret->rawlen] = '\0';
*datalen = secret->rawlen;
return 0;
}
char *qcrypto_secret_lookup_as_utf8(const char *secretid,
Error **errp)
{
uint8_t *data;
size_t datalen;
if (qcrypto_secret_lookup(secretid,
&data,
&datalen,
errp) < 0) {
return NULL;
}
if (!g_utf8_validate((const gchar *)data, datalen, NULL)) {
error_setg(errp,
"Data from secret %s is not valid UTF-8",
secretid);
g_free(data);
return NULL;
}
return (char *)data;
}
char *qcrypto_secret_lookup_as_base64(const char *secretid,
Error **errp)
{
uint8_t *data;
size_t datalen;
char *ret;
if (qcrypto_secret_lookup(secretid,
&data,
&datalen,
errp) < 0) {
return NULL;
}
ret = g_base64_encode(data, datalen);
g_free(data);
return ret;
}
static const TypeInfo qcrypto_secret_info = {
.parent = TYPE_OBJECT,
.name = TYPE_QCRYPTO_SECRET_COMMON,
.instance_size = sizeof(QCryptoSecretCommon),
.instance_finalize = qcrypto_secret_finalize,
.class_size = sizeof(QCryptoSecretCommonClass),
.class_init = qcrypto_secret_class_init,
.abstract = true,
};
static void
qcrypto_secret_register_types(void)
{
type_register_static(&qcrypto_secret_info);
}
type_init(qcrypto_secret_register_types);
