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