xemu/crypto/init.c
Daniel P. Berrange 91bfcdb01d crypto: allow use of nettle/gcrypt to be selected explicitly
Currently the choice of whether to use nettle or gcrypt is
made based on what gnutls is linked to. There are times
when it is desirable to be able to force build against a
specific library. For example, if testing changes to QEMU's
crypto code all 3 possible backends need to be checked
regardless of what the local gnutls uses.

It is also desirable to be able to enable nettle/gcrypt
for cipher/hash algorithms, without enabling gnutls
for TLS support.

This gives two new configure flags, which allow the
following possibilities

Automatically determine nettle vs gcrypt from what
gnutls links to (recommended to minimize number of
crypto libraries linked to)

 ./configure

Automatically determine nettle vs gcrypt based on
which is installed

 ./configure --disable-gnutls

Force use of nettle

 ./configure --enable-nettle

Force use of gcrypt

 ./configure --enable-gcrypt

Force use of built-in AES & crippled-DES

 ./configure --disable-nettle --disable-gcrypt

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2015-10-22 19:03:07 +01:00

149 lines
3.8 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 "crypto/init.h"
#include "qemu/thread.h"
#ifdef CONFIG_GNUTLS
#include <gnutls/gnutls.h>
#include <gnutls/crypto.h>
#endif
#ifdef CONFIG_GCRYPT
#include <gcrypt.h>
#endif
/* #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) || \
!defined(GNUTLS_VERSION_NUMBER) || \
(GNUTLS_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 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;
}
#ifdef QCRYPTO_INIT_GCRYPT_THREADS
gcry_control(GCRYCTL_SET_THREAD_CBS, &qcrypto_gcrypt_thread_impl);
#endif /* QCRYPTO_INIT_GCRYPT_THREADS */
gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
#endif
return 0;
}