crypto/rand/rand_lib.c - third_party/openssl - Git at Google

 /*
  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (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
  */

 #include <stdio.h>
 #include <time.h>
 #include "internal/cryptlib.h"
 #include <openssl/opensslconf.h>
 #include "internal/rand_int.h"
 #include <openssl/engine.h>
 #include "internal/thread_once.h"
 #include "rand_lcl.h"

 #ifndef OPENSSL_NO_ENGINE
 /* non-NULL if default_RAND_meth is ENGINE-provided */
 static ENGINE *funct_ref;
 static CRYPTO_RWLOCK *rand_engine_lock;
 #endif
 static CRYPTO_RWLOCK *rand_meth_lock;
 static const RAND_METHOD *default_RAND_meth;
 static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
 RAND_BYTES_BUFFER rand_bytes;
 int rand_fork_count;

 #ifdef OPENSSL_RAND_SEED_RDTSC
 /*
  * IMPORTANT NOTE:  It is not currently possible to use this code
  * because we are not sure about the amount of randomness it provides.
  * Some SP900 tests have been run, but there is internal skepticism.
  * So for now this code is not used.
  */
 # error "RDTSC enabled?  Should not be possible!"

 /*
  * Since we get some randomness from the low-order bits of the
  * high-speec clock, it can help.  But don't return a status since
  * it's not sufficient to indicate whether or not the seeding was
  * done.
  */
 void rand_read_tsc(RAND_poll_fn cb, void *arg)
 {
     unsigned char c;
     int i;

     if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
         for (i = 0; i < TSC_READ_COUNT; i++) {
             c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
             cb(arg, &c, 1, 0.5);
         }
     }
 }
 #endif

 #ifdef OPENSSL_RAND_SEED_RDCPU
 size_t OPENSSL_ia32_rdseed_bytes(char *buf, size_t len);
 size_t OPENSSL_ia32_rdrand_bytes(char *buf, size_t len);

 extern unsigned int OPENSSL_ia32cap_P[];

 int rand_read_cpu(RAND_poll_fn cb, void *arg)
 {
     char buff[RANDOMNESS_NEEDED];

     /* If RDSEED is available, use that. */
     if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
         if (OPENSSL_ia32_rdseed_bytes(buff, sizeof(buff)) == sizeof(buff)) {
             cb(arg, buff, (int)sizeof(buff), sizeof(buff));
             return 1;
         }
     }

     /* Second choice is RDRAND. */
     if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
         if (OPENSSL_ia32_rdrand_bytes(buff, sizeof(buff)) == sizeof(buff)) {
             cb(arg, buff, (int)sizeof(buff), sizeof(buff));
             return 1;
         }
     }

     return 0;
 }
 #endif


 /*
  * DRBG has two sets of callbacks; we only discuss the "entropy" one
  * here.  When the DRBG needs additional randomness bits (called entropy
  * in the NIST document), it calls the get_entropy callback which fills in
  * a pointer and returns the number of bytes. When the DRBG is finished with
  * the buffer, it calls the cleanup_entropy callback, with the value of
  * the buffer that the get_entropy callback filled in.
  *
  * Get entropy from the system, via RAND_poll if needed.  The |entropy|
  * is the bits of randomness required, and is expected to fit into a buffer
  * of |min_len|..|max__len| size.  We assume we're getting high-quality
  * randomness from the system, and that |min_len| bytes will do.
  */
 size_t drbg_entropy_from_system(RAND_DRBG *drbg,
                                 unsigned char **pout,
                                 int entropy, size_t min_len, size_t max_len)
 {
     int i;


     if (min_len > (size_t)drbg->size) {
         /* Should not happen.  See comment near RANDOMNESS_NEEDED. */
         min_len = drbg->size;
     }

     if (drbg->filled) {
         /* Re-use what we have. */
         *pout = drbg->randomness;
         return drbg->size;
     }

     /* If we don't have enough, try to get more. */
     CRYPTO_THREAD_write_lock(rand_bytes.lock);
     for (i = RAND_POLL_RETRIES; rand_bytes.curr < min_len && --i >= 0; ) {
         CRYPTO_THREAD_unlock(rand_bytes.lock);
         RAND_poll();
         CRYPTO_THREAD_write_lock(rand_bytes.lock);
     }

     /* Get desired amount, but no more than we have. */
     if (min_len > rand_bytes.curr)
         min_len = rand_bytes.curr;
     if (min_len != 0) {
         memcpy(drbg->randomness, rand_bytes.buff, min_len);
         drbg->filled = 1;
         /* Update amount left and shift it down. */
         rand_bytes.curr -= min_len;
         if (rand_bytes.curr != 0)
             memmove(rand_bytes.buff, &rand_bytes.buff[min_len], rand_bytes.curr);
     }
     CRYPTO_THREAD_unlock(rand_bytes.lock);
     *pout = drbg->randomness;
     return min_len;
 }

 size_t drbg_entropy_from_parent(RAND_DRBG *drbg,
                                 unsigned char **pout,
                                 int entropy, size_t min_len, size_t max_len)
 {
     int st;

     if (min_len > (size_t)drbg->size) {
         /* Should not happen.  See comment near RANDOMNESS_NEEDED. */
         min_len = drbg->size;
     }

     /* Get random from parent, include our state as additional input. */
     st = RAND_DRBG_generate(drbg->parent, drbg->randomness, min_len, 0,
                             (unsigned char *)drbg, sizeof(*drbg));
     if (st == 0)
         return 0;
     drbg->filled = 1;
     *pout = drbg->randomness;
     return min_len;
 }

 void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out)
 {
     drbg->filled = 0;
     OPENSSL_cleanse(drbg->randomness, drbg->size);
 }


 /*
  * Set up a global DRBG.
  */
 static int setup_drbg(RAND_DRBG *drbg)
 {
     int ret = 1;

     drbg->lock = CRYPTO_THREAD_lock_new();
     ret &= drbg->lock != NULL;
     drbg->size = RANDOMNESS_NEEDED;
     drbg->secure = CRYPTO_secure_malloc_initialized();
     drbg->randomness = drbg->secure
         ? OPENSSL_secure_malloc(drbg->size)
         : OPENSSL_malloc(drbg->size);
     ret &= drbg->randomness != NULL;
     /* If you change these parameters, see RANDOMNESS_NEEDED */
     ret &= RAND_DRBG_set(drbg,
                          NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1;
     ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system,
                                    drbg_release_entropy, NULL, NULL) == 1;
     return ret;
 }

 static void free_drbg(RAND_DRBG *drbg)
 {
     CRYPTO_THREAD_lock_free(drbg->lock);
     if (drbg->secure)
         OPENSSL_secure_clear_free(drbg->randomness, drbg->size);
     else
         OPENSSL_clear_free(drbg->randomness, drbg->size);
     RAND_DRBG_uninstantiate(drbg);
 }

 void rand_fork()
 {
     rand_fork_count++;
 }

 DEFINE_RUN_ONCE_STATIC(do_rand_init)
 {
     int ret = 1;

 #ifndef OPENSSL_NO_ENGINE
     rand_engine_lock = CRYPTO_THREAD_lock_new();
     ret &= rand_engine_lock != NULL;
 #endif
     rand_meth_lock = CRYPTO_THREAD_lock_new();
     ret &= rand_meth_lock != NULL;

     rand_bytes.lock = CRYPTO_THREAD_lock_new();
     ret &= rand_bytes.lock != NULL;
     rand_bytes.curr = 0;
     rand_bytes.size = MAX_RANDOMNESS_HELD;
     rand_bytes.secure = CRYPTO_secure_malloc_initialized();
     rand_bytes.buff = rand_bytes.secure
         ? OPENSSL_secure_malloc(rand_bytes.size)
         : OPENSSL_malloc(rand_bytes.size);
     ret &= rand_bytes.buff != NULL;
     ret &= setup_drbg(&rand_drbg);
     ret &= setup_drbg(&priv_drbg);
     return ret;
 }

 void rand_cleanup_int(void)
 {
     const RAND_METHOD *meth = default_RAND_meth;

     if (meth != NULL && meth->cleanup != NULL)
         meth->cleanup();
     RAND_set_rand_method(NULL);
 #ifndef OPENSSL_NO_ENGINE
     CRYPTO_THREAD_lock_free(rand_engine_lock);
 #endif
     CRYPTO_THREAD_lock_free(rand_meth_lock);
     CRYPTO_THREAD_lock_free(rand_bytes.lock);
     if (rand_bytes.secure)
         OPENSSL_secure_clear_free(rand_bytes.buff, rand_bytes.size);
     else
         OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size);
     free_drbg(&rand_drbg);
     free_drbg(&priv_drbg);
 }

 /*
  * RAND_poll_ex() gets a function pointer to call when it has random bytes.
  * RAND_poll() sets the function pointer to be a wrapper that calls RAND_add().
  */
 static void call_rand_add(void* arg, const void *buf, int num, double r)
 {
     RAND_add(buf, num, r);
 }

 int RAND_poll(void)
 {
     return RAND_poll_ex(call_rand_add, NULL);
 }

 int RAND_set_rand_method(const RAND_METHOD *meth)
 {
     if (!RUN_ONCE(&rand_init, do_rand_init))
         return 0;

     CRYPTO_THREAD_write_lock(rand_meth_lock);
 #ifndef OPENSSL_NO_ENGINE
     ENGINE_finish(funct_ref);
     funct_ref = NULL;
 #endif
     default_RAND_meth = meth;
     CRYPTO_THREAD_unlock(rand_meth_lock);
     return 1;
 }

 const RAND_METHOD *RAND_get_rand_method(void)
 {
     const RAND_METHOD *tmp_meth = NULL;

     if (!RUN_ONCE(&rand_init, do_rand_init))
         return NULL;

     CRYPTO_THREAD_write_lock(rand_meth_lock);
     if (default_RAND_meth == NULL) {
 #ifndef OPENSSL_NO_ENGINE
         ENGINE *e;

         /* If we have an engine that can do RAND, use it. */
         if ((e = ENGINE_get_default_RAND()) != NULL
                 && (tmp_meth = ENGINE_get_RAND(e)) != NULL) {
             funct_ref = e;
             default_RAND_meth = tmp_meth;
         } else {
             ENGINE_finish(e);
             default_RAND_meth = &rand_meth;
         }
 #else
         default_RAND_meth = &rand_meth;
 #endif
     }
     tmp_meth = default_RAND_meth;
     CRYPTO_THREAD_unlock(rand_meth_lock);
     return tmp_meth;
 }

 #ifndef OPENSSL_NO_ENGINE
 int RAND_set_rand_engine(ENGINE *engine)
 {
     const RAND_METHOD *tmp_meth = NULL;

     if (!RUN_ONCE(&rand_init, do_rand_init))
         return 0;

     if (engine != NULL) {
         if (!ENGINE_init(engine))
             return 0;
         tmp_meth = ENGINE_get_RAND(engine);
         if (tmp_meth == NULL) {
             ENGINE_finish(engine);
             return 0;
         }
     }
     CRYPTO_THREAD_write_lock(rand_engine_lock);
     /* This function releases any prior ENGINE so call it first */
     RAND_set_rand_method(tmp_meth);
     funct_ref = engine;
     CRYPTO_THREAD_unlock(rand_engine_lock);
     return 1;
 }
 #endif

 void RAND_seed(const void *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();

     if (meth->seed != NULL)
         meth->seed(buf, num);
 }

 void RAND_add(const void *buf, int num, double randomness)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();

     if (meth->add != NULL)
         meth->add(buf, num, randomness);
 }

 /*
  * This function is not part of RAND_METHOD, so if we're not using
  * the default method, then just call RAND_bytes().  Otherwise make
  * sure we're instantiated and use the private DRBG.
  */
 int RAND_priv_bytes(unsigned char *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();

     if (meth != RAND_OpenSSL())
         return RAND_bytes(buf, num);

     if (priv_drbg.state == DRBG_UNINITIALISED
             && RAND_DRBG_instantiate(&priv_drbg, NULL, 0) == 0)
         return 0;
     return RAND_DRBG_generate(&priv_drbg, buf, num, 0, NULL, 0);

 }

 int RAND_bytes(unsigned char *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();

     if (meth->bytes != NULL)
         return meth->bytes(buf, num);
     RANDerr(RAND_F_RAND_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
     return -1;
 }

 #if OPENSSL_API_COMPAT < 0x10100000L
 int RAND_pseudo_bytes(unsigned char *buf, int num)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();

     if (meth->pseudorand != NULL)
         return meth->pseudorand(buf, num);
     return -1;
 }
 #endif

 int RAND_status(void)
 {
     const RAND_METHOD *meth = RAND_get_rand_method();

     if (meth->status != NULL)
         return meth->status();
     return 0;
 }
	/*
	* Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
	*
	* Licensed under the OpenSSL license (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
	*/

	#include <stdio.h>
	#include <time.h>
	#include "internal/cryptlib.h"
	#include <openssl/opensslconf.h>
	#include "internal/rand_int.h"
	#include <openssl/engine.h>
	#include "internal/thread_once.h"
	#include "rand_lcl.h"

	#ifndef OPENSSL_NO_ENGINE
	/* non-NULL if default_RAND_meth is ENGINE-provided */
	static ENGINE *funct_ref;
	static CRYPTO_RWLOCK *rand_engine_lock;
	#endif
	static CRYPTO_RWLOCK *rand_meth_lock;
	static const RAND_METHOD *default_RAND_meth;
	static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
	RAND_BYTES_BUFFER rand_bytes;
	int rand_fork_count;

	#ifdef OPENSSL_RAND_SEED_RDTSC
	/*
	* IMPORTANT NOTE: It is not currently possible to use this code
	* because we are not sure about the amount of randomness it provides.
	* Some SP900 tests have been run, but there is internal skepticism.
	* So for now this code is not used.
	*/
	# error "RDTSC enabled? Should not be possible!"

	/*
	* Since we get some randomness from the low-order bits of the
	* high-speec clock, it can help. But don't return a status since
	* it's not sufficient to indicate whether or not the seeding was
	* done.
	*/
	void rand_read_tsc(RAND_poll_fn cb, void *arg)
	{
	unsigned char c;
	int i;

	if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
	for (i = 0; i < TSC_READ_COUNT; i++) {
	c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
	cb(arg, &c, 1, 0.5);
	}
	}
	}
	#endif

	#ifdef OPENSSL_RAND_SEED_RDCPU
	size_t OPENSSL_ia32_rdseed_bytes(char *buf, size_t len);
	size_t OPENSSL_ia32_rdrand_bytes(char *buf, size_t len);

	extern unsigned int OPENSSL_ia32cap_P[];

	int rand_read_cpu(RAND_poll_fn cb, void *arg)
	{
	char buff[RANDOMNESS_NEEDED];

	/* If RDSEED is available, use that. */
	if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
	if (OPENSSL_ia32_rdseed_bytes(buff, sizeof(buff)) == sizeof(buff)) {
	cb(arg, buff, (int)sizeof(buff), sizeof(buff));
	return 1;
	}
	}

	/* Second choice is RDRAND. */
	if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
	if (OPENSSL_ia32_rdrand_bytes(buff, sizeof(buff)) == sizeof(buff)) {
	cb(arg, buff, (int)sizeof(buff), sizeof(buff));
	return 1;
	}
	}

	return 0;
	}
	#endif


	/*
	* DRBG has two sets of callbacks; we only discuss the "entropy" one
	* here. When the DRBG needs additional randomness bits (called entropy
	* in the NIST document), it calls the get_entropy callback which fills in
	* a pointer and returns the number of bytes. When the DRBG is finished with
	* the buffer, it calls the cleanup_entropy callback, with the value of
	* the buffer that the get_entropy callback filled in.
	*
	* Get entropy from the system, via RAND_poll if needed. The \|entropy\|
	* is the bits of randomness required, and is expected to fit into a buffer
	* of \|min_len\|..\|max__len\| size. We assume we're getting high-quality
	* randomness from the system, and that \|min_len\| bytes will do.
	*/
	size_t drbg_entropy_from_system(RAND_DRBG *drbg,
	unsigned char **pout,
	int entropy, size_t min_len, size_t max_len)
	{
	int i;


	if (min_len > (size_t)drbg->size) {
	/* Should not happen. See comment near RANDOMNESS_NEEDED. */
	min_len = drbg->size;
	}

	if (drbg->filled) {
	/* Re-use what we have. */
	*pout = drbg->randomness;
	return drbg->size;
	}

	/* If we don't have enough, try to get more. */
	CRYPTO_THREAD_write_lock(rand_bytes.lock);
	for (i = RAND_POLL_RETRIES; rand_bytes.curr < min_len && --i >= 0; ) {
	CRYPTO_THREAD_unlock(rand_bytes.lock);
	RAND_poll();
	CRYPTO_THREAD_write_lock(rand_bytes.lock);
	}

	/* Get desired amount, but no more than we have. */
	if (min_len > rand_bytes.curr)
	min_len = rand_bytes.curr;
	if (min_len != 0) {
	memcpy(drbg->randomness, rand_bytes.buff, min_len);
	drbg->filled = 1;
	/* Update amount left and shift it down. */
	rand_bytes.curr -= min_len;
	if (rand_bytes.curr != 0)
	memmove(rand_bytes.buff, &rand_bytes.buff[min_len], rand_bytes.curr);
	}
	CRYPTO_THREAD_unlock(rand_bytes.lock);
	*pout = drbg->randomness;
	return min_len;
	}

	size_t drbg_entropy_from_parent(RAND_DRBG *drbg,
	unsigned char **pout,
	int entropy, size_t min_len, size_t max_len)
	{
	int st;

	if (min_len > (size_t)drbg->size) {
	/* Should not happen. See comment near RANDOMNESS_NEEDED. */
	min_len = drbg->size;
	}

	/* Get random from parent, include our state as additional input. */
	st = RAND_DRBG_generate(drbg->parent, drbg->randomness, min_len, 0,
	(unsigned char )drbg, sizeof(drbg));
	if (st == 0)
	return 0;
	drbg->filled = 1;
	*pout = drbg->randomness;
	return min_len;
	}

	void drbg_release_entropy(RAND_DRBG drbg, unsigned char out)
	{
	drbg->filled = 0;
	OPENSSL_cleanse(drbg->randomness, drbg->size);
	}


	/*
	* Set up a global DRBG.
	*/
	static int setup_drbg(RAND_DRBG *drbg)
	{
	int ret = 1;

	drbg->lock = CRYPTO_THREAD_lock_new();
	ret &= drbg->lock != NULL;
	drbg->size = RANDOMNESS_NEEDED;
	drbg->secure = CRYPTO_secure_malloc_initialized();
	drbg->randomness = drbg->secure
	? OPENSSL_secure_malloc(drbg->size)
	: OPENSSL_malloc(drbg->size);
	ret &= drbg->randomness != NULL;
	/* If you change these parameters, see RANDOMNESS_NEEDED */
	ret &= RAND_DRBG_set(drbg,
	NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1;
	ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system,
	drbg_release_entropy, NULL, NULL) == 1;
	return ret;
	}

	static void free_drbg(RAND_DRBG *drbg)
	{
	CRYPTO_THREAD_lock_free(drbg->lock);
	if (drbg->secure)
	OPENSSL_secure_clear_free(drbg->randomness, drbg->size);
	else
	OPENSSL_clear_free(drbg->randomness, drbg->size);
	RAND_DRBG_uninstantiate(drbg);
	}

	void rand_fork()
	{
	rand_fork_count++;
	}

	DEFINE_RUN_ONCE_STATIC(do_rand_init)
	{
	int ret = 1;

	#ifndef OPENSSL_NO_ENGINE
	rand_engine_lock = CRYPTO_THREAD_lock_new();
	ret &= rand_engine_lock != NULL;
	#endif
	rand_meth_lock = CRYPTO_THREAD_lock_new();
	ret &= rand_meth_lock != NULL;

	rand_bytes.lock = CRYPTO_THREAD_lock_new();
	ret &= rand_bytes.lock != NULL;
	rand_bytes.curr = 0;
	rand_bytes.size = MAX_RANDOMNESS_HELD;
	rand_bytes.secure = CRYPTO_secure_malloc_initialized();
	rand_bytes.buff = rand_bytes.secure
	? OPENSSL_secure_malloc(rand_bytes.size)
	: OPENSSL_malloc(rand_bytes.size);
	ret &= rand_bytes.buff != NULL;
	ret &= setup_drbg(&rand_drbg);
	ret &= setup_drbg(&priv_drbg);
	return ret;
	}

	void rand_cleanup_int(void)
	{
	const RAND_METHOD *meth = default_RAND_meth;

	if (meth != NULL && meth->cleanup != NULL)
	meth->cleanup();
	RAND_set_rand_method(NULL);
	#ifndef OPENSSL_NO_ENGINE
	CRYPTO_THREAD_lock_free(rand_engine_lock);
	#endif
	CRYPTO_THREAD_lock_free(rand_meth_lock);
	CRYPTO_THREAD_lock_free(rand_bytes.lock);
	if (rand_bytes.secure)
	OPENSSL_secure_clear_free(rand_bytes.buff, rand_bytes.size);
	else
	OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size);
	free_drbg(&rand_drbg);
	free_drbg(&priv_drbg);
	}

	/*
	* RAND_poll_ex() gets a function pointer to call when it has random bytes.
	* RAND_poll() sets the function pointer to be a wrapper that calls RAND_add().
	*/
	static void call_rand_add(void* arg, const void *buf, int num, double r)
	{
	RAND_add(buf, num, r);
	}

	int RAND_poll(void)
	{
	return RAND_poll_ex(call_rand_add, NULL);
	}

	int RAND_set_rand_method(const RAND_METHOD *meth)
	{
	if (!RUN_ONCE(&rand_init, do_rand_init))
	return 0;

	CRYPTO_THREAD_write_lock(rand_meth_lock);
	#ifndef OPENSSL_NO_ENGINE
	ENGINE_finish(funct_ref);
	funct_ref = NULL;
	#endif
	default_RAND_meth = meth;
	CRYPTO_THREAD_unlock(rand_meth_lock);
	return 1;
	}

	const RAND_METHOD *RAND_get_rand_method(void)
	{
	const RAND_METHOD *tmp_meth = NULL;

	if (!RUN_ONCE(&rand_init, do_rand_init))
	return NULL;

	CRYPTO_THREAD_write_lock(rand_meth_lock);
	if (default_RAND_meth == NULL) {
	#ifndef OPENSSL_NO_ENGINE
	ENGINE *e;

	/* If we have an engine that can do RAND, use it. */
	if ((e = ENGINE_get_default_RAND()) != NULL
	&& (tmp_meth = ENGINE_get_RAND(e)) != NULL) {
	funct_ref = e;
	default_RAND_meth = tmp_meth;
	} else {
	ENGINE_finish(e);
	default_RAND_meth = &rand_meth;
	}
	#else
	default_RAND_meth = &rand_meth;
	#endif
	}
	tmp_meth = default_RAND_meth;
	CRYPTO_THREAD_unlock(rand_meth_lock);
	return tmp_meth;
	}

	#ifndef OPENSSL_NO_ENGINE
	int RAND_set_rand_engine(ENGINE *engine)
	{
	const RAND_METHOD *tmp_meth = NULL;

	if (!RUN_ONCE(&rand_init, do_rand_init))
	return 0;

	if (engine != NULL) {
	if (!ENGINE_init(engine))
	return 0;
	tmp_meth = ENGINE_get_RAND(engine);
	if (tmp_meth == NULL) {
	ENGINE_finish(engine);
	return 0;
	}
	}
	CRYPTO_THREAD_write_lock(rand_engine_lock);
	/* This function releases any prior ENGINE so call it first */
	RAND_set_rand_method(tmp_meth);
	funct_ref = engine;
	CRYPTO_THREAD_unlock(rand_engine_lock);
	return 1;
	}
	#endif

	void RAND_seed(const void *buf, int num)
	{
	const RAND_METHOD *meth = RAND_get_rand_method();

	if (meth->seed != NULL)
	meth->seed(buf, num);
	}

	void RAND_add(const void *buf, int num, double randomness)
	{
	const RAND_METHOD *meth = RAND_get_rand_method();

	if (meth->add != NULL)
	meth->add(buf, num, randomness);
	}

	/*
	* This function is not part of RAND_METHOD, so if we're not using
	* the default method, then just call RAND_bytes(). Otherwise make
	* sure we're instantiated and use the private DRBG.
	*/
	int RAND_priv_bytes(unsigned char *buf, int num)
	{
	const RAND_METHOD *meth = RAND_get_rand_method();

	if (meth != RAND_OpenSSL())
	return RAND_bytes(buf, num);

	if (priv_drbg.state == DRBG_UNINITIALISED
	&& RAND_DRBG_instantiate(&priv_drbg, NULL, 0) == 0)
	return 0;
	return RAND_DRBG_generate(&priv_drbg, buf, num, 0, NULL, 0);

	}

	int RAND_bytes(unsigned char *buf, int num)
	{
	const RAND_METHOD *meth = RAND_get_rand_method();

	if (meth->bytes != NULL)
	return meth->bytes(buf, num);
	RANDerr(RAND_F_RAND_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
	return -1;
	}

	#if OPENSSL_API_COMPAT < 0x10100000L
	int RAND_pseudo_bytes(unsigned char *buf, int num)
	{
	const RAND_METHOD *meth = RAND_get_rand_method();

	if (meth->pseudorand != NULL)
	return meth->pseudorand(buf, num);
	return -1;
	}
	#endif

	int RAND_status(void)
	{
	const RAND_METHOD *meth = RAND_get_rand_method();

	if (meth->status != NULL)
	return meth->status();
	return 0;
	}