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Diffstat (limited to 'openssl/crypto/rand/md_rand.c')
| -rw-r--r-- | openssl/crypto/rand/md_rand.c | 584 |
1 files changed, 584 insertions, 0 deletions
diff --git a/openssl/crypto/rand/md_rand.c b/openssl/crypto/rand/md_rand.c new file mode 100644 index 000000000..0f8dd3e00 --- /dev/null +++ b/openssl/crypto/rand/md_rand.c @@ -0,0 +1,584 @@ +/* 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 OPENSSL_FIPS +#include <openssl/fips.h> +#endif + + +#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 OPENSSL_FIPS + if(FIPS_mode()) + { + FIPSerr(FIPS_F_SSLEAY_RAND_BYTES,FIPS_R_NON_FIPS_METHOD); + return 0; + } +#endif + +#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; + } |