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/*
* Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/*
* Implementation of the FIPS 140-2 section 4.9.2 Conditional Tests.
*/
#include <string.h>
#include "internal/rand_int.h"
#include "internal/thread_once.h"
#include "rand_lcl.h"
static RAND_POOL *crngt_pool;
static unsigned char *crngt_prev;
int (*crngt_get_entropy)(unsigned char *) = &rand_crngt_get_entropy_cb;
int rand_crngt_get_entropy_cb(unsigned char *buf)
{
size_t n;
unsigned char *p;
while ((n = rand_pool_acquire_entropy(crngt_pool)) != 0)
if (n >= CRNGT_BUFSIZ) {
p = rand_pool_detach(crngt_pool);
memcpy(buf, p, CRNGT_BUFSIZ);
rand_pool_reattach(crngt_pool, p);
return 1;
}
return 0;
}
void rand_crngt_cleanup(void)
{
rand_pool_free(crngt_pool);
OPENSSL_secure_free(crngt_prev);
crngt_pool = NULL;
crngt_prev = NULL;
}
int rand_crngt_init(void)
{
if ((crngt_pool = rand_pool_new(0, CRNGT_BUFSIZ, CRNGT_BUFSIZ)) == NULL)
return 0;
if ((crngt_prev = OPENSSL_secure_malloc(CRNGT_BUFSIZ)) != NULL
&& crngt_get_entropy(crngt_prev))
return 1;
rand_crngt_cleanup();
return 0;
}
static CRYPTO_ONCE rand_crngt_init_flag = CRYPTO_ONCE_STATIC_INIT;
DEFINE_RUN_ONCE_STATIC(do_rand_crngt_init)
{
return OPENSSL_init_crypto(0, NULL)
&& rand_crngt_init()
&& OPENSSL_atexit(&rand_crngt_cleanup);
}
int rand_crngt_single_init(void)
{
return RUN_ONCE(&rand_crngt_init_flag, do_rand_crngt_init);
}
size_t rand_crngt_get_entropy(RAND_DRBG *drbg,
unsigned char **pout,
int entropy, size_t min_len, size_t max_len,
int prediction_resistance)
{
unsigned char buf[CRNGT_BUFSIZ];
RAND_POOL *pool;
size_t q, r = 0, s, t = 0;
int attempts = 3;
if (!RUN_ONCE(&rand_crngt_init_flag, do_rand_crngt_init))
return 0;
if ((pool = rand_pool_new(entropy, min_len, max_len)) == NULL)
return 0;
while ((q = rand_pool_bytes_needed(pool, 1)) > 0 && attempts-- > 0) {
s = q > sizeof(buf) ? sizeof(buf) : q;
if (!crngt_get_entropy(buf)
|| memcmp(crngt_prev, buf, CRNGT_BUFSIZ) == 0
|| !rand_pool_add(pool, buf, s, s * 8))
goto err;
memcpy(crngt_prev, buf, CRNGT_BUFSIZ);
t += s;
attempts++;
}
r = t;
*pout = rand_pool_detach(pool);
err:
rand_pool_free(pool);
return r;
}
void rand_crngt_cleanup_entropy(RAND_DRBG *drbg,
unsigned char *out, size_t outlen)
{
OPENSSL_secure_clear_free(out, outlen);
}
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