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/*
* Copyright (C) 2008-2012 Free Software Foundation, Inc.
*
* Author: Nikos Mavrogiannopoulos
*
* This file is part of GnuTLS.
*
* The GnuTLS 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 program. If not, see <https://www.gnu.org/licenses/>
*
*/
/* This file handles all the internal functions that cope with random data.
*/
#include "gnutls_int.h"
#include "errors.h"
#include <random.h>
#include "locks.h"
#include <fips.h>
#include "gthreads.h"
#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)
extern gnutls_crypto_rnd_st _gnutls_fuzz_rnd_ops;
#endif
/* Per thread context of random generator, and a flag to indicate initialization */
static _Thread_local void *gnutls_rnd_ctx;
static _Thread_local unsigned rnd_initialized = 0;
struct rnd_ctx_list_st {
void *ctx;
struct rnd_ctx_list_st *next;
};
/* A global list of all allocated contexts - to be
* used during deinitialization. */
GNUTLS_STATIC_MUTEX(gnutls_rnd_ctx_list_mutex);
static struct rnd_ctx_list_st *head = NULL;
static int append(void *ctx)
{
struct rnd_ctx_list_st *e = gnutls_malloc(sizeof(*e));
if (e == NULL)
return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
e->ctx = ctx;
e->next = head;
head = e;
return 0;
}
inline static int _gnutls_rnd_init(void)
{
if (unlikely(!rnd_initialized)) {
int ret;
if (_gnutls_rnd_ops.init == NULL) {
rnd_initialized = 1;
return 0;
}
if (_gnutls_rnd_ops.init(&gnutls_rnd_ctx) < 0) {
gnutls_assert();
return GNUTLS_E_RANDOM_FAILED;
}
GNUTLS_STATIC_MUTEX_LOCK(gnutls_rnd_ctx_list_mutex);
ret = append(gnutls_rnd_ctx);
GNUTLS_STATIC_MUTEX_UNLOCK(gnutls_rnd_ctx_list_mutex);
if (ret < 0) {
gnutls_assert();
_gnutls_rnd_ops.deinit(gnutls_rnd_ctx);
return ret;
}
rnd_initialized = 1;
}
return 0;
}
int _gnutls_rnd_preinit(void)
{
int ret;
#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)
# warning Insecure PRNG is enabled
ret = gnutls_crypto_rnd_register(100, &_gnutls_fuzz_rnd_ops);
if (ret < 0)
return ret;
#elif defined(ENABLE_FIPS140)
/* The FIPS140 random generator is only enabled when we are compiled
* with FIPS support, _and_ the system requires FIPS140.
*/
if (_gnutls_fips_mode_enabled() == 1) {
ret = gnutls_crypto_rnd_register(100, &_gnutls_fips_rnd_ops);
if (ret < 0)
return ret;
}
#endif
ret = _rnd_system_entropy_init();
if (ret < 0) {
gnutls_assert();
return GNUTLS_E_RANDOM_FAILED;
}
return 0;
}
void _gnutls_rnd_deinit(void)
{
if (_gnutls_rnd_ops.deinit != NULL) {
struct rnd_ctx_list_st *e = head, *next;
while(e != NULL) {
next = e->next;
_gnutls_rnd_ops.deinit(e->ctx);
gnutls_free(e);
e = next;
}
head = NULL;
}
rnd_initialized = 0;
_rnd_system_entropy_deinit();
return;
}
/**
* gnutls_rnd:
* @level: a security level
* @data: place to store random bytes
* @len: The requested size
*
* This function will generate random data and store it to output
* buffer. The value of @level should be one of %GNUTLS_RND_NONCE,
* %GNUTLS_RND_RANDOM and %GNUTLS_RND_KEY. See the manual and
* %gnutls_rnd_level_t for detailed information.
*
* This function is thread-safe and also fork-safe.
*
* Returns: Zero on success, or a negative error code on error.
*
* Since: 2.12.0
**/
int gnutls_rnd(gnutls_rnd_level_t level, void *data, size_t len)
{
int ret;
FAIL_IF_LIB_ERROR;
if (unlikely((ret=_gnutls_rnd_init()) < 0))
return gnutls_assert_val(ret);
if (likely(len > 0)) {
return _gnutls_rnd_ops.rnd(gnutls_rnd_ctx, level, data,
len);
}
return 0;
}
/**
* gnutls_rnd_refresh:
*
* This function refreshes the random generator state.
* That is the current precise time, CPU usage, and
* other values are input into its state.
*
* On a slower rate input from /dev/urandom is mixed too.
*
* Since: 3.1.7
**/
void gnutls_rnd_refresh(void)
{
if (rnd_initialized && _gnutls_rnd_ops.rnd_refresh)
_gnutls_rnd_ops.rnd_refresh(gnutls_rnd_ctx);
}
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