/* 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 "openssl/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]; 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); 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(local_md,&m); 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; } } OPENSSL_cleanse((char *)&m,sizeof(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 < 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(THREADS) && !defined(WIN32) assert(md_c[1] == md_count[1]); #endif } static void ssleay_rand_seed(const void *buf, int num) { ssleay_rand_add(buf, num, 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]; 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; /* 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(local_md,&m); 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(md,&m); CRYPTO_w_unlock(CRYPTO_LOCK_RAND); OPENSSL_cleanse(&m,sizeof(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) (void)ERR_get_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; }