/* 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). */ #include #include #include #include #include #include #include "internal.h" #include "../../internal.h" #include "../rand/internal.h" static const uint8_t kDefaultAdditionalData[32] = {0}; int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) { uint8_t *buf = NULL; int ret = 0, bit, bytes, mask; if (rnd == NULL) { return 0; } if (top != BN_RAND_TOP_ANY && top != BN_RAND_TOP_ONE && top != BN_RAND_TOP_TWO) { OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); return 0; } if (bottom != BN_RAND_BOTTOM_ANY && bottom != BN_RAND_BOTTOM_ODD) { OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); return 0; } if (bits == 0) { BN_zero(rnd); return 1; } bytes = (bits + 7) / 8; bit = (bits - 1) % 8; mask = 0xff << (bit + 1); buf = OPENSSL_malloc(bytes); if (buf == NULL) { OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE); goto err; } // Make a random number and set the top and bottom bits. RAND_bytes(buf, bytes); if (top != BN_RAND_TOP_ANY) { if (top == BN_RAND_TOP_TWO && bits > 1) { if (bit == 0) { buf[0] = 1; buf[1] |= 0x80; } else { buf[0] |= (3 << (bit - 1)); } } else { buf[0] |= (1 << bit); } } buf[0] &= ~mask; // Set the bottom bit if requested, if (bottom == BN_RAND_BOTTOM_ODD) { buf[bytes - 1] |= 1; } if (!BN_bin2bn(buf, bytes, rnd)) { goto err; } ret = 1; err: OPENSSL_free(buf); return ret; } int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) { return BN_rand(rnd, bits, top, bottom); } // bn_less_than_word returns one if the number represented by |len| words at |a| // is less than |b| and zero otherwise. It performs this computation in time // independent of the value of |a|. |b| is assumed public. static int bn_less_than_word(const BN_ULONG *a, size_t len, BN_ULONG b) { if (b == 0) { return 0; } if (len == 0) { return 1; } // |a| < |b| iff a[1..len-1] are all zero and a[0] < b. OPENSSL_COMPILE_ASSERT(sizeof(BN_ULONG) <= sizeof(crypto_word_t), crypto_word_t_too_small); crypto_word_t mask = 0; for (size_t i = 1; i < len; i++) { mask |= a[i]; } // |mask| is now zero iff a[1..len-1] are all zero. mask = constant_time_is_zero_w(mask); mask &= constant_time_lt_w(a[0], b); return constant_time_select_int(mask, 1, 0); } int bn_in_range_words(const BN_ULONG *a, BN_ULONG min_inclusive, const BN_ULONG *max_exclusive, size_t len) { return bn_less_than_words(a, max_exclusive, len) && !bn_less_than_word(a, len, min_inclusive); } int bn_rand_range_words(BN_ULONG *out, BN_ULONG min_inclusive, const BN_ULONG *max_exclusive, size_t len, const uint8_t additional_data[32]) { // This function implements the equivalent of steps 4 through 7 of FIPS 186-4 // appendices B.4.2 and B.5.2. When called in those contexts, |max_exclusive| // is n and |min_inclusive| is one. // Compute the bit length of |max_exclusive| (step 1), in terms of a number of // |words| worth of entropy to fill and a mask of bits to clear in the top // word. size_t words = len; while (words > 0 && max_exclusive[words - 1] == 0) { words--; } if (words == 0 || (words == 1 && max_exclusive[0] <= min_inclusive)) { OPENSSL_PUT_ERROR(BN, BN_R_INVALID_RANGE); return 0; } BN_ULONG mask = max_exclusive[words - 1]; // This sets all bits in |mask| below the most significant bit. mask |= mask >> 1; mask |= mask >> 2; mask |= mask >> 4; mask |= mask >> 8; mask |= mask >> 16; #if defined(OPENSSL_64_BIT) mask |= mask >> 32; #endif // Fill any unused words with zero. OPENSSL_memset(out + words, 0, (len - words) * sizeof(BN_ULONG)); unsigned count = 100; do { if (!--count) { OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_ITERATIONS); return 0; } // Steps 4 and 5. Use |words| and |mask| together to obtain a string of N // bits, where N is the bit length of |max_exclusive|. RAND_bytes_with_additional_data((uint8_t *)out, words * sizeof(BN_ULONG), additional_data); out[words - 1] &= mask; // If out >= max_exclusive or out < min_inclusive, retry. This implements // the equivalent of steps 6 and 7 without leaking the value of |out|. } while (!bn_in_range_words(out, min_inclusive, max_exclusive, words)); return 1; } int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive, const BIGNUM *max_exclusive) { if (!bn_wexpand(r, max_exclusive->top) || !bn_rand_range_words(r->d, min_inclusive, max_exclusive->d, max_exclusive->top, kDefaultAdditionalData)) { return 0; } r->neg = 0; r->top = max_exclusive->top; bn_correct_top(r); return 1; } int BN_rand_range(BIGNUM *r, const BIGNUM *range) { return BN_rand_range_ex(r, 0, range); } int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) { return BN_rand_range(r, range); }