sl@0: /* crypto/rand/md_rand.c */
sl@0: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
sl@0:  * All rights reserved.
sl@0:  *
sl@0:  * This package is an SSL implementation written
sl@0:  * by Eric Young (eay@cryptsoft.com).
sl@0:  * The implementation was written so as to conform with Netscapes SSL.
sl@0:  * 
sl@0:  * This library is free for commercial and non-commercial use as long as
sl@0:  * the following conditions are aheared to.  The following conditions
sl@0:  * apply to all code found in this distribution, be it the RC4, RSA,
sl@0:  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
sl@0:  * included with this distribution is covered by the same copyright terms
sl@0:  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
sl@0:  * 
sl@0:  * Copyright remains Eric Young's, and as such any Copyright notices in
sl@0:  * the code are not to be removed.
sl@0:  * If this package is used in a product, Eric Young should be given attribution
sl@0:  * as the author of the parts of the library used.
sl@0:  * This can be in the form of a textual message at program startup or
sl@0:  * in documentation (online or textual) provided with the package.
sl@0:  * 
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  * 1. Redistributions of source code must retain the copyright
sl@0:  *    notice, this list of conditions and the following disclaimer.
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in the
sl@0:  *    documentation and/or other materials provided with the distribution.
sl@0:  * 3. All advertising materials mentioning features or use of this software
sl@0:  *    must display the following acknowledgement:
sl@0:  *    "This product includes cryptographic software written by
sl@0:  *     Eric Young (eay@cryptsoft.com)"
sl@0:  *    The word 'cryptographic' can be left out if the rouines from the library
sl@0:  *    being used are not cryptographic related :-).
sl@0:  * 4. If you include any Windows specific code (or a derivative thereof) from 
sl@0:  *    the apps directory (application code) you must include an acknowledgement:
sl@0:  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
sl@0:  * 
sl@0:  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
sl@0:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
sl@0:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
sl@0:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
sl@0:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
sl@0:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
sl@0:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
sl@0:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
sl@0:  * SUCH DAMAGE.
sl@0:  * 
sl@0:  * The licence and distribution terms for any publically available version or
sl@0:  * derivative of this code cannot be changed.  i.e. this code cannot simply be
sl@0:  * copied and put under another distribution licence
sl@0:  * [including the GNU Public Licence.]
sl@0:  */
sl@0: /* ====================================================================
sl@0:  * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
sl@0:  *
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  *
sl@0:  * 1. Redistributions of source code must retain the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer. 
sl@0:  *
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in
sl@0:  *    the documentation and/or other materials provided with the
sl@0:  *    distribution.
sl@0:  *
sl@0:  * 3. All advertising materials mentioning features or use of this
sl@0:  *    software must display the following acknowledgment:
sl@0:  *    "This product includes software developed by the OpenSSL Project
sl@0:  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
sl@0:  *
sl@0:  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
sl@0:  *    endorse or promote products derived from this software without
sl@0:  *    prior written permission. For written permission, please contact
sl@0:  *    openssl-core@openssl.org.
sl@0:  *
sl@0:  * 5. Products derived from this software may not be called "OpenSSL"
sl@0:  *    nor may "OpenSSL" appear in their names without prior written
sl@0:  *    permission of the OpenSSL Project.
sl@0:  *
sl@0:  * 6. Redistributions of any form whatsoever must retain the following
sl@0:  *    acknowledgment:
sl@0:  *    "This product includes software developed by the OpenSSL Project
sl@0:  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
sl@0:  *
sl@0:  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
sl@0:  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
sl@0:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
sl@0:  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
sl@0:  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
sl@0:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
sl@0:  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
sl@0:  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
sl@0:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
sl@0:  * OF THE POSSIBILITY OF SUCH DAMAGE.
sl@0:  * ====================================================================
sl@0:  *
sl@0:  * This product includes cryptographic software written by Eric Young
sl@0:  * (eay@cryptsoft.com).  This product includes software written by Tim
sl@0:  * Hudson (tjh@cryptsoft.com).
sl@0:  *
sl@0:  */
sl@0:  /*
sl@0:  © Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.
sl@0:  */
sl@0: 
sl@0: 
sl@0: #ifdef MD_RAND_DEBUG
sl@0: # ifndef NDEBUG
sl@0: #   define NDEBUG
sl@0: # endif
sl@0: #endif
sl@0: 
sl@0: #include <assert.h>
sl@0: #include <stdio.h>
sl@0: #include <string.h>
sl@0: 
sl@0: #include "e_os.h"
sl@0: 
sl@0: #include <openssl/rand.h>
sl@0: #include "rand_lcl.h"
sl@0: 
sl@0: #include <openssl/crypto.h>
sl@0: #include <openssl/err.h>
sl@0: #if (defined(SYMBIAN) && (defined(__WINSCW__) || defined(__WINS__)))
sl@0: #include "libcrypto_wsd_macros.h"
sl@0: #include "libcrypto_wsd.h"
sl@0: #endif
sl@0: 
sl@0: 
sl@0: #ifdef BN_DEBUG
sl@0: # define PREDICT
sl@0: #endif
sl@0: 
sl@0: /* #define PREDICT	1 */
sl@0: 
sl@0: #define STATE_SIZE	1023
sl@0: 
sl@0: #ifndef EMULATOR
sl@0: static int state_num=0,state_index=0;
sl@0: static unsigned char state[STATE_SIZE+MD_DIGEST_LENGTH];
sl@0: static unsigned char md[MD_DIGEST_LENGTH];
sl@0: static long md_count[2]={0,0};
sl@0: static double entropy=0;
sl@0: static int initialized=0;
sl@0: 
sl@0: static unsigned int crypto_lock_rand = 0; /* may be set only when a thread
sl@0:                                            * holds CRYPTO_LOCK_RAND
sl@0:                                            * (to prevent double locking) */
sl@0: /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
sl@0: static unsigned long locking_thread = 0; /* valid iff crypto_lock_rand is set */
sl@0: #else
sl@0: GET_STATIC_VAR_FROM_TLS(state_num,md_rand,int)
sl@0: #define state_num (*GET_WSD_VAR_NAME(state_num,md_rand, s)())
sl@0: 
sl@0: GET_STATIC_VAR_FROM_TLS(state_index,md_rand,int)
sl@0: #define state_index (*GET_WSD_VAR_NAME(state_index,md_rand, s)())
sl@0: 
sl@0: GET_STATIC_ARRAY_FROM_TLS(state,md_rand,unsigned char)
sl@0: #define state (GET_WSD_VAR_NAME(state,md_rand, s)())
sl@0: 
sl@0: GET_STATIC_ARRAY_FROM_TLS(md,md_rand,unsigned char)
sl@0: #define md (GET_WSD_VAR_NAME(md,md_rand, s)())
sl@0:  
sl@0: GET_STATIC_ARRAY_FROM_TLS(md_count,md_rand,unsigned char)
sl@0: #define md_count (GET_WSD_VAR_NAME(md_count,md_rand, s)())
sl@0:  
sl@0: GET_STATIC_VAR_FROM_TLS(entropy,md_rand,double)
sl@0: #define entropy (*GET_WSD_VAR_NAME(entropy,md_rand, s)())
sl@0: 
sl@0: GET_STATIC_VAR_FROM_TLS(initialized,md_rand,int)
sl@0: #define initialized (*GET_WSD_VAR_NAME(initialized,md_rand, s)())
sl@0: 
sl@0: GET_STATIC_VAR_FROM_TLS(crypto_lock_rand,md_rand,unsigned int)
sl@0: #define crypto_lock_rand (*GET_WSD_VAR_NAME(crypto_lock_rand,md_rand, s)())
sl@0: 
sl@0: GET_STATIC_VAR_FROM_TLS(locking_thread,md_rand,unsigned long)
sl@0: #define locking_thread  (*GET_WSD_VAR_NAME(locking_thread,md_rand, s)())
sl@0: 
sl@0: #endif
sl@0: 
sl@0: #ifdef PREDICT
sl@0: int rand_predictable=0;
sl@0: #endif
sl@0: 
sl@0: const char RAND_version[]="RAND" OPENSSL_VERSION_PTEXT;
sl@0: 
sl@0: static void ssleay_rand_cleanup(void);
sl@0: static void ssleay_rand_seed(const void *buf, int num);
sl@0: static void ssleay_rand_add(const void *buf, int num, double add_entropy);
sl@0: static int ssleay_rand_bytes(unsigned char *buf, int num);
sl@0: static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num);
sl@0: static int ssleay_rand_status(void);
sl@0: 
sl@0: #ifndef EMULATOR
sl@0: RAND_METHOD rand_ssleay_meth={
sl@0: 	ssleay_rand_seed,
sl@0: 	ssleay_rand_bytes,
sl@0: 	ssleay_rand_cleanup,
sl@0: 	ssleay_rand_add,
sl@0: 	ssleay_rand_pseudo_bytes,
sl@0: 	ssleay_rand_status
sl@0: 	}; 
sl@0: #else
sl@0: 
sl@0: GET_GLOBAL_VAR_FROM_TLS(rand_ssleay_meth,md_rand, RAND_METHOD)
sl@0: #define rand_ssleay_meth (*GET_WSD_VAR_NAME(rand_ssleay_meth,md_rand, g)())
sl@0: const RAND_METHOD temp_g_rand_ssleay_meth={
sl@0: 	ssleay_rand_seed,
sl@0: 	ssleay_rand_bytes,
sl@0: 	ssleay_rand_cleanup,
sl@0: 	ssleay_rand_add,
sl@0: 	ssleay_rand_pseudo_bytes,
sl@0: 	ssleay_rand_status
sl@0: 	}; 
sl@0: 
sl@0: #endif
sl@0: EXPORT_C RAND_METHOD *RAND_SSLeay(void)
sl@0: 	{
sl@0: 	return(&rand_ssleay_meth);
sl@0: 	}
sl@0: 
sl@0: static void ssleay_rand_cleanup(void)
sl@0: 	{
sl@0: 	OPENSSL_cleanse(state,sizeof(state));
sl@0: 	state_num=0;
sl@0: 	state_index=0;
sl@0: 	OPENSSL_cleanse(md,MD_DIGEST_LENGTH);
sl@0: 	md_count[0]=0;
sl@0: 	md_count[1]=0;
sl@0: 	entropy=0;
sl@0: 	initialized=0;
sl@0: 	}
sl@0: 
sl@0: static void ssleay_rand_add(const void *buf, int num, double add)
sl@0: 	{
sl@0: 	int i,j,k,st_idx;
sl@0: 	long md_c[2];
sl@0: 	unsigned char local_md[MD_DIGEST_LENGTH];
sl@0: 	EVP_MD_CTX m;
sl@0: 	int do_not_lock;
sl@0: 
sl@0: 	/*
sl@0: 	 * (Based on the rand(3) manpage)
sl@0: 	 *
sl@0: 	 * The input is chopped up into units of 20 bytes (or less for
sl@0: 	 * the last block).  Each of these blocks is run through the hash
sl@0: 	 * function as follows:  The data passed to the hash function
sl@0: 	 * is the current 'md', the same number of bytes from the 'state'
sl@0: 	 * (the location determined by in incremented looping index) as
sl@0: 	 * the current 'block', the new key data 'block', and 'count'
sl@0: 	 * (which is incremented after each use).
sl@0: 	 * The result of this is kept in 'md' and also xored into the
sl@0: 	 * 'state' at the same locations that were used as input into the
sl@0:          * hash function.
sl@0: 	 */
sl@0: 
sl@0: 	/* check if we already have the lock */
sl@0: 	if (crypto_lock_rand)
sl@0: 		{
sl@0: 		CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
sl@0: 		do_not_lock = (locking_thread == CRYPTO_thread_id());
sl@0: 		CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
sl@0: 		}
sl@0: 	else
sl@0: 		do_not_lock = 0;
sl@0: 
sl@0: 	if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
sl@0: 	st_idx=state_index;
sl@0: 
sl@0: 	/* use our own copies of the counters so that even
sl@0: 	 * if a concurrent thread seeds with exactly the
sl@0: 	 * same data and uses the same subarray there's _some_
sl@0: 	 * difference */
sl@0: 	md_c[0] = md_count[0];
sl@0: 	md_c[1] = md_count[1];
sl@0: 
sl@0: 	memcpy(local_md, md, sizeof md);
sl@0: 
sl@0: 	/* state_index <= state_num <= STATE_SIZE */
sl@0: 	state_index += num;
sl@0: 	if (state_index >= STATE_SIZE)
sl@0: 		{
sl@0: 		state_index%=STATE_SIZE;
sl@0: 		state_num=STATE_SIZE;
sl@0: 		}
sl@0: 	else if (state_num < STATE_SIZE)	
sl@0: 		{
sl@0: 		if (state_index > state_num)
sl@0: 			state_num=state_index;
sl@0: 		}
sl@0: 	/* state_index <= state_num <= STATE_SIZE */
sl@0: 
sl@0: 	/* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
sl@0: 	 * are what we will use now, but other threads may use them
sl@0: 	 * as well */
sl@0: 
sl@0: 	md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
sl@0: 
sl@0: 	if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
sl@0: 
sl@0: 	EVP_MD_CTX_init(&m);
sl@0: 	for (i=0; i<num; i+=MD_DIGEST_LENGTH)
sl@0: 		{
sl@0: 		j=(num-i);
sl@0: 		j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
sl@0: 
sl@0: 		MD_Init(&m);
sl@0: 		MD_Update(&m,local_md,MD_DIGEST_LENGTH);
sl@0: 		k=(st_idx+j)-STATE_SIZE;
sl@0: 		if (k > 0)
sl@0: 			{
sl@0: 			MD_Update(&m,&(state[st_idx]),j-k);
sl@0: 			MD_Update(&m,&(state[0]),k);
sl@0: 			}
sl@0: 		else
sl@0: 			MD_Update(&m,&(state[st_idx]),j);
sl@0: 			
sl@0: 		MD_Update(&m,buf,j);
sl@0: 		MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
sl@0: 		MD_Final(&m,local_md);
sl@0: 		md_c[1]++;
sl@0: 
sl@0: 		buf=(const char *)buf + j;
sl@0: 
sl@0: 		for (k=0; k<j; k++)
sl@0: 			{
sl@0: 			/* Parallel threads may interfere with this,
sl@0: 			 * but always each byte of the new state is
sl@0: 			 * the XOR of some previous value of its
sl@0: 			 * and local_md (itermediate values may be lost).
sl@0: 			 * Alway using locking could hurt performance more
sl@0: 			 * than necessary given that conflicts occur only
sl@0: 			 * when the total seeding is longer than the random
sl@0: 			 * state. */
sl@0: 			state[st_idx++]^=local_md[k];
sl@0: 			if (st_idx >= STATE_SIZE)
sl@0: 				st_idx=0;
sl@0: 			}
sl@0: 		}
sl@0: 	EVP_MD_CTX_cleanup(&m);
sl@0: 
sl@0: 	if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
sl@0: 	/* Don't just copy back local_md into md -- this could mean that
sl@0: 	 * other thread's seeding remains without effect (except for
sl@0: 	 * the incremented counter).  By XORing it we keep at least as
sl@0: 	 * much entropy as fits into md. */
sl@0: 	for (k = 0; k < (int)sizeof(md); k++)
sl@0: 		{
sl@0: 		md[k] ^= local_md[k];
sl@0: 		}
sl@0: 	if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
sl@0: 	    entropy += add;
sl@0: 	if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
sl@0: 	
sl@0: #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
sl@0: 	assert(md_c[1] == md_count[1]);
sl@0: #endif
sl@0: 	}
sl@0: 
sl@0: static void ssleay_rand_seed(const void *buf, int num)
sl@0: 	{
sl@0: 	ssleay_rand_add(buf, num, (double)num);
sl@0: 	}
sl@0: #ifdef EMULATOR
sl@0: GET_STATIC_VAR_FROM_TLS(stirred_pool,md_rand,volatile int)
sl@0: #define stirred_pool (*GET_WSD_VAR_NAME(stirred_pool,md_rand, s)())
sl@0: #endif
sl@0: static int ssleay_rand_bytes(unsigned char *buf, int num)
sl@0: 	{
sl@0: #ifndef EMULATOR	
sl@0: 	static volatile int stirred_pool = 0;
sl@0: #endif	
sl@0: 	int i,j,k,st_num,st_idx;
sl@0: 	int num_ceil;
sl@0: 	int ok;
sl@0: 	long md_c[2];
sl@0: 	unsigned char local_md[MD_DIGEST_LENGTH];
sl@0: 	EVP_MD_CTX m;
sl@0: #ifndef GETPID_IS_MEANINGLESS
sl@0: 	pid_t curr_pid = getpid();
sl@0: #endif
sl@0: 	int do_stir_pool = 0;
sl@0: 
sl@0: #ifdef PREDICT
sl@0: 	if (rand_predictable)
sl@0: 		{
sl@0: 		static unsigned char val=0;
sl@0: 
sl@0: 		for (i=0; i<num; i++)
sl@0: 			buf[i]=val++;
sl@0: 		return(1);
sl@0: 		}
sl@0: #endif
sl@0: 
sl@0: 	if (num <= 0)
sl@0: 		return 1;
sl@0: 
sl@0: 	EVP_MD_CTX_init(&m);
sl@0: 	/* round upwards to multiple of MD_DIGEST_LENGTH/2 */
sl@0: 	num_ceil = (1 + (num-1)/(MD_DIGEST_LENGTH/2)) * (MD_DIGEST_LENGTH/2);
sl@0: 
sl@0: 	/*
sl@0: 	 * (Based on the rand(3) manpage:)
sl@0: 	 *
sl@0: 	 * For each group of 10 bytes (or less), we do the following:
sl@0: 	 *
sl@0: 	 * Input into the hash function the local 'md' (which is initialized from
sl@0: 	 * the global 'md' before any bytes are generated), the bytes that are to
sl@0: 	 * be overwritten by the random bytes, and bytes from the 'state'
sl@0: 	 * (incrementing looping index). From this digest output (which is kept
sl@0: 	 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
sl@0: 	 * bottom 10 bytes are xored into the 'state'.
sl@0: 	 * 
sl@0: 	 * Finally, after we have finished 'num' random bytes for the
sl@0: 	 * caller, 'count' (which is incremented) and the local and global 'md'
sl@0: 	 * are fed into the hash function and the results are kept in the
sl@0: 	 * global 'md'.
sl@0: 	 */
sl@0: 
sl@0: 	CRYPTO_w_lock(CRYPTO_LOCK_RAND);
sl@0: 
sl@0: 	/* prevent ssleay_rand_bytes() from trying to obtain the lock again */
sl@0: 	CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
sl@0: 	locking_thread = CRYPTO_thread_id();
sl@0: 	CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
sl@0: 	crypto_lock_rand = 1;
sl@0: 
sl@0: 	if (!initialized)
sl@0: 		{
sl@0: 		RAND_poll();
sl@0: 		initialized = 1;
sl@0: 		}
sl@0: 	
sl@0: 	if (!stirred_pool)
sl@0: 		do_stir_pool = 1;
sl@0: 	
sl@0: 	ok = (entropy >= ENTROPY_NEEDED);
sl@0: 	if (!ok)
sl@0: 		{
sl@0: 		/* If the PRNG state is not yet unpredictable, then seeing
sl@0: 		 * the PRNG output may help attackers to determine the new
sl@0: 		 * state; thus we have to decrease the entropy estimate.
sl@0: 		 * Once we've had enough initial seeding we don't bother to
sl@0: 		 * adjust the entropy count, though, because we're not ambitious
sl@0: 		 * to provide *information-theoretic* randomness.
sl@0: 		 *
sl@0: 		 * NOTE: This approach fails if the program forks before
sl@0: 		 * we have enough entropy. Entropy should be collected
sl@0: 		 * in a separate input pool and be transferred to the
sl@0: 		 * output pool only when the entropy limit has been reached.
sl@0: 		 */
sl@0: 		entropy -= num;
sl@0: 		if (entropy < 0)
sl@0: 			entropy = 0;
sl@0: 		}
sl@0: 
sl@0: 	if (do_stir_pool)
sl@0: 		{
sl@0: 		/* In the output function only half of 'md' remains secret,
sl@0: 		 * so we better make sure that the required entropy gets
sl@0: 		 * 'evenly distributed' through 'state', our randomness pool.
sl@0: 		 * The input function (ssleay_rand_add) chains all of 'md',
sl@0: 		 * which makes it more suitable for this purpose.
sl@0: 		 */
sl@0: 
sl@0: 		int n = STATE_SIZE; /* so that the complete pool gets accessed */
sl@0: 		while (n > 0)
sl@0: 			{
sl@0: #if MD_DIGEST_LENGTH > 20
sl@0: # error "Please adjust DUMMY_SEED."
sl@0: #endif
sl@0: #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
sl@0: 			/* Note that the seed does not matter, it's just that
sl@0: 			 * ssleay_rand_add expects to have something to hash. */
sl@0: 			ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
sl@0: 			n -= MD_DIGEST_LENGTH;
sl@0: 			}
sl@0: 		if (ok)
sl@0: 			stirred_pool = 1;
sl@0: 		}
sl@0: 
sl@0: 	st_idx=state_index;
sl@0: 	st_num=state_num;
sl@0: 	md_c[0] = md_count[0];
sl@0: 	md_c[1] = md_count[1];
sl@0: 	memcpy(local_md, md, sizeof md);
sl@0: 
sl@0: 	state_index+=num_ceil;
sl@0: 	if (state_index > state_num)
sl@0: 		state_index %= state_num;
sl@0: 
sl@0: 	/* state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num]
sl@0: 	 * are now ours (but other threads may use them too) */
sl@0: 
sl@0: 	md_count[0] += 1;
sl@0: 
sl@0: 	/* before unlocking, we must clear 'crypto_lock_rand' */
sl@0: 	crypto_lock_rand = 0;
sl@0: 	CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
sl@0: 
sl@0: 	while (num > 0)
sl@0: 		{
sl@0: 		/* num_ceil -= MD_DIGEST_LENGTH/2 */
sl@0: 		j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
sl@0: 		num-=j;
sl@0: 		MD_Init(&m);
sl@0: #ifndef GETPID_IS_MEANINGLESS
sl@0: 		if (curr_pid) /* just in the first iteration to save time */
sl@0: 			{
sl@0: 			MD_Update(&m,(unsigned char*)&curr_pid,sizeof curr_pid);
sl@0: 			curr_pid = 0;
sl@0: 			}
sl@0: #endif
sl@0: 		MD_Update(&m,local_md,MD_DIGEST_LENGTH);
sl@0: 		MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
sl@0: #ifndef PURIFY
sl@0: 		MD_Update(&m,buf,j); /* purify complains */
sl@0: #endif
sl@0: 		k=(st_idx+MD_DIGEST_LENGTH/2)-st_num;
sl@0: 		if (k > 0)
sl@0: 			{
sl@0: 			MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2-k);
sl@0: 			MD_Update(&m,&(state[0]),k);
sl@0: 			}
sl@0: 		else
sl@0: 			MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2);
sl@0: 		MD_Final(&m,local_md);
sl@0: 
sl@0: 		for (i=0; i<MD_DIGEST_LENGTH/2; i++)
sl@0: 			{
sl@0: 			state[st_idx++]^=local_md[i]; /* may compete with other threads */
sl@0: 			if (st_idx >= st_num)
sl@0: 				st_idx=0;
sl@0: 			if (i < j)
sl@0: 				*(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
sl@0: 			}
sl@0: 		}
sl@0: 
sl@0: 	MD_Init(&m);
sl@0: 	MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
sl@0: 	MD_Update(&m,local_md,MD_DIGEST_LENGTH);
sl@0: 	CRYPTO_w_lock(CRYPTO_LOCK_RAND);
sl@0: 	MD_Update(&m,md,MD_DIGEST_LENGTH);
sl@0: 	MD_Final(&m,md);
sl@0: 	CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
sl@0: 
sl@0: 	EVP_MD_CTX_cleanup(&m);
sl@0: 	if (ok)
sl@0: 		return(1);
sl@0: 	else
sl@0: 		{
sl@0: 		RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED);
sl@0: 		ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
sl@0: 			"http://www.openssl.org/support/faq.html");
sl@0: 		return(0);
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: /* pseudo-random bytes that are guaranteed to be unique but not
sl@0:    unpredictable */
sl@0: static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num) 
sl@0: 	{
sl@0: 	int ret;
sl@0: 	unsigned long err;
sl@0: 
sl@0: 	ret = RAND_bytes(buf, num);
sl@0: 	if (ret == 0)
sl@0: 		{
sl@0: 		err = ERR_peek_error();
sl@0: 		if (ERR_GET_LIB(err) == ERR_LIB_RAND &&
sl@0: 		    ERR_GET_REASON(err) == RAND_R_PRNG_NOT_SEEDED)
sl@0: 			ERR_clear_error();
sl@0: 		}
sl@0: 	return (ret);
sl@0: 	}
sl@0: 
sl@0: static int ssleay_rand_status(void)
sl@0: 	{
sl@0: 	int ret;
sl@0: 	int do_not_lock;
sl@0: 
sl@0: 	/* check if we already have the lock
sl@0: 	 * (could happen if a RAND_poll() implementation calls RAND_status()) */
sl@0: 	if (crypto_lock_rand)
sl@0: 		{
sl@0: 		CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
sl@0: 		do_not_lock = (locking_thread == CRYPTO_thread_id());
sl@0: 		CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
sl@0: 		}
sl@0: 	else
sl@0: 		do_not_lock = 0;
sl@0: 	
sl@0: 	if (!do_not_lock)
sl@0: 		{
sl@0: 		CRYPTO_w_lock(CRYPTO_LOCK_RAND);
sl@0: 		
sl@0: 		/* prevent ssleay_rand_bytes() from trying to obtain the lock again */
sl@0: 		CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
sl@0: 		locking_thread = CRYPTO_thread_id();
sl@0: 		CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
sl@0: 		crypto_lock_rand = 1;
sl@0: 		}
sl@0: 	
sl@0: 	if (!initialized)
sl@0: 		{
sl@0: 		RAND_poll();
sl@0: 		initialized = 1;
sl@0: 		}
sl@0: 
sl@0: 	ret = entropy >= ENTROPY_NEEDED;
sl@0: 
sl@0: 	if (!do_not_lock)
sl@0: 		{
sl@0: 		/* before unlocking, we must clear 'crypto_lock_rand' */
sl@0: 		crypto_lock_rand = 0;
sl@0: 		
sl@0: 		CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
sl@0: 		}
sl@0: 	
sl@0: 	return ret;
sl@0: 	}