qemu/crypto/init.c
Geert Martin Ijewski a37278169d crypto: qcrypto_random_bytes() now works on windows w/o any other crypto libs
If no crypto library is included in the build, QEMU uses
qcrypto_random_bytes() to generate random data. That function tried to open
/dev/urandom or /dev/random and if opening both files failed it errored out.

Those files obviously do not exist on windows, so there the code uses
CryptGenRandom().

Furthermore there was some refactoring and a new function
qcrypto_random_init() was introduced. If a proper crypto library (gnutls or
libgcrypt) is included in the build, this function does nothing. If neither
is included it initializes the (platform specific) handles that are used by
qcrypto_random_bytes().
Either:
* a handle to /dev/urandom | /dev/random on unix like systems
* a handle to a cryptographic service provider on windows

Signed-off-by: Geert Martin Ijewski <gm.ijewski@web.de>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2017-05-09 14:41:47 +01:00

156 lines
3.9 KiB
C

/*
* QEMU Crypto initialization
*
* 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 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/init.h"
#include "qapi/error.h"
#include "qemu/thread.h"
#ifdef CONFIG_GNUTLS
#include <gnutls/gnutls.h>
#include <gnutls/crypto.h>
#endif
#ifdef CONFIG_GCRYPT
#include <gcrypt.h>
#endif
#include "crypto/random.h"
/* #define DEBUG_GNUTLS */
/*
* If GNUTLS is built against GCrypt then
*
* - When GNUTLS >= 2.12, we must not initialize gcrypt threading
* because GNUTLS will do that itself
* - When GNUTLS < 2.12 we must always initialize gcrypt threading
* - When GNUTLS is disabled we must always initialize gcrypt threading
*
* But....
*
* When gcrypt >= 1.6.0 we must not initialize gcrypt threading
* because gcrypt will do that itself.
*
* So we need to init gcrypt threading if
*
* - gcrypt < 1.6.0
* AND
* - gnutls < 2.12
* OR
* - gnutls is disabled
*
*/
#if (defined(CONFIG_GCRYPT) && \
(!defined(CONFIG_GNUTLS) || \
(LIBGNUTLS_VERSION_NUMBER < 0x020c00)) && \
(!defined(GCRYPT_VERSION_NUMBER) || \
(GCRYPT_VERSION_NUMBER < 0x010600)))
#define QCRYPTO_INIT_GCRYPT_THREADS
#else
#undef QCRYPTO_INIT_GCRYPT_THREADS
#endif
#ifdef DEBUG_GNUTLS
static void qcrypto_gnutls_log(int level, const char *str)
{
fprintf(stderr, "%d: %s", level, str);
}
#endif
#ifdef QCRYPTO_INIT_GCRYPT_THREADS
static int qcrypto_gcrypt_mutex_init(void **priv)
{ \
QemuMutex *lock = NULL;
lock = g_new0(QemuMutex, 1);
qemu_mutex_init(lock);
*priv = lock;
return 0;
}
static int qcrypto_gcrypt_mutex_destroy(void **priv)
{
QemuMutex *lock = *priv;
qemu_mutex_destroy(lock);
g_free(lock);
return 0;
}
static int qcrypto_gcrypt_mutex_lock(void **priv)
{
QemuMutex *lock = *priv;
qemu_mutex_lock(lock);
return 0;
}
static int qcrypto_gcrypt_mutex_unlock(void **priv)
{
QemuMutex *lock = *priv;
qemu_mutex_unlock(lock);
return 0;
}
static struct gcry_thread_cbs qcrypto_gcrypt_thread_impl = {
(GCRY_THREAD_OPTION_PTHREAD | (GCRY_THREAD_OPTION_VERSION << 8)),
NULL,
qcrypto_gcrypt_mutex_init,
qcrypto_gcrypt_mutex_destroy,
qcrypto_gcrypt_mutex_lock,
qcrypto_gcrypt_mutex_unlock,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
};
#endif /* QCRYPTO_INIT_GCRYPT */
int qcrypto_init(Error **errp)
{
#ifdef QCRYPTO_INIT_GCRYPT_THREADS
gcry_control(GCRYCTL_SET_THREAD_CBS, &qcrypto_gcrypt_thread_impl);
#endif /* QCRYPTO_INIT_GCRYPT_THREADS */
#ifdef CONFIG_GNUTLS
int ret;
ret = gnutls_global_init();
if (ret < 0) {
error_setg(errp,
"Unable to initialize GNUTLS library: %s",
gnutls_strerror(ret));
return -1;
}
#ifdef DEBUG_GNUTLS
gnutls_global_set_log_level(10);
gnutls_global_set_log_function(qcrypto_gnutls_log);
#endif
#endif
#ifdef CONFIG_GCRYPT
if (!gcry_check_version(GCRYPT_VERSION)) {
error_setg(errp, "Unable to initialize gcrypt");
return -1;
}
gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
#endif
if (qcrypto_random_init(errp) < 0) {
return -1;
}
return 0;
}