/* crypto/bn/bn_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.] */ #include <stdio.h> #include <time.h> #include "cryptlib.h" #include "bn_lcl.h" #include <openssl/rand.h> static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom) { unsigned char *buf=NULL; int ret=0,bit,bytes,mask; time_t tim; if (bits == 0) { BN_zero(rnd); return 1; } bytes=(bits+7)/8; bit=(bits-1)%8; mask=0xff<<(bit+1); buf=(unsigned char *)Malloc(bytes); if (buf == NULL) { BNerr(BN_F_BN_RAND,ERR_R_MALLOC_FAILURE); goto err; } /* make a random number and set the top and bottom bits */ time(&tim); RAND_add(&tim,sizeof(tim),0); if (pseudorand) { if (RAND_pseudo_bytes(buf, bytes) == -1) goto err; } else { if (RAND_bytes(buf, bytes) <= 0) goto err; } #if 1 if (pseudorand == 2) { /* generate patterns that are more likely to trigger BN library bugs */ int i; unsigned char c; for (i = 0; i < bytes; i++) { RAND_pseudo_bytes(&c, 1); if (c >= 128 && i > 0) buf[i] = buf[i-1]; else if (c < 42) buf[i] = 0; else if (c < 84) buf[i] = 255; } } #endif if (top != -1) { if (top) { if (bit == 0) { buf[0]=1; buf[1]|=0x80; } else { buf[0]|=(3<<(bit-1)); } } else { buf[0]|=(1<<bit); } } buf[0] &= ~mask; if (bottom) /* set bottom bit if requested */ buf[bytes-1]|=1; if (!BN_bin2bn(buf,bytes,rnd)) goto err; ret=1; err: if (buf != NULL) { memset(buf,0,bytes); Free(buf); } return(ret); } int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) { return bnrand(0, rnd, bits, top, bottom); } int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) { return bnrand(1, rnd, bits, top, bottom); } #if 1 int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom) { return bnrand(2, rnd, bits, top, bottom); } #endif /* random number r: 0 <= r < range */ int BN_rand_range(BIGNUM *r, BIGNUM *range) { int n; if (range->neg || BN_is_zero(range)) { BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE); return 0; } n = BN_num_bits(range); /* n > 0 */ if (n == 1) { if (!BN_zero(r)) return 0; } else if (BN_is_bit_set(range, n - 2)) { do { /* range = 11..._2, so each iteration succeeds with probability >= .75 */ if (!BN_rand(r, n, -1, 0)) return 0; } while (BN_cmp(r, range) >= 0); } else { /* range = 10..._2, * so 3*range (= 11..._2) is exactly one bit longer than range */ do { if (!BN_rand(r, n + 1, -1, 0)) return 0; /* If r < 3*range, use r := r MOD range * (which is either r, r - range, or r - 2*range). * Otherwise, iterate once more. * Since 3*range = 11..._2, each iteration succeeds with * probability >= .75. */ if (BN_cmp(r ,range) >= 0) { if (!BN_sub(r, r, range)) return 0; if (BN_cmp(r, range) >= 0) if (!BN_sub(r, r, range)) return 0; } } while (BN_cmp(r, range) >= 0); } return 1; }