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