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291 lines
10 KiB
291 lines
10 KiB
/* crypto/bn/bn_rand.c */ |
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
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* All rights reserved. |
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* |
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* This package is an SSL implementation written |
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* by Eric Young (eay@cryptsoft.com). |
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* The implementation was written so as to conform with Netscapes SSL. |
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* |
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* This library is free for commercial and non-commercial use as long as |
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* the following conditions are aheared to. The following conditions |
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* apply to all code found in this distribution, be it the RC4, RSA, |
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation |
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* included with this distribution is covered by the same copyright terms |
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* except that the holder is Tim Hudson (tjh@cryptsoft.com). |
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* |
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* Copyright remains Eric Young's, and as such any Copyright notices in |
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* the code are not to be removed. |
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* If this package is used in a product, Eric Young should be given attribution |
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* as the author of the parts of the library used. |
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* This can be in the form of a textual message at program startup or |
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* in documentation (online or textual) provided with the package. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. All advertising materials mentioning features or use of this software |
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* must display the following acknowledgement: |
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* "This product includes cryptographic software written by |
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* Eric Young (eay@cryptsoft.com)" |
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* The word 'cryptographic' can be left out if the rouines from the library |
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* being used are not cryptographic related :-). |
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* 4. If you include any Windows specific code (or a derivative thereof) from |
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* the apps directory (application code) you must include an acknowledgement: |
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* |
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* The licence and distribution terms for any publically available version or |
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* derivative of this code cannot be changed. i.e. this code cannot simply be |
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* copied and put under another distribution licence |
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* [including the GNU Public Licence.] |
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*/ |
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/* ==================================================================== |
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* Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* 3. All advertising materials mentioning features or use of this |
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* software must display the following acknowledgment: |
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* "This product includes software developed by the OpenSSL Project |
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)" |
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* |
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
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* endorse or promote products derived from this software without |
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* prior written permission. For written permission, please contact |
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* openssl-core@openssl.org. |
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* |
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* 5. Products derived from this software may not be called "OpenSSL" |
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* nor may "OpenSSL" appear in their names without prior written |
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* permission of the OpenSSL Project. |
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* |
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* 6. Redistributions of any form whatsoever must retain the following |
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* acknowledgment: |
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* "This product includes software developed by the OpenSSL Project |
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
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* OF THE POSSIBILITY OF SUCH DAMAGE. |
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* ==================================================================== |
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* |
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* This product includes cryptographic software written by Eric Young |
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* (eay@cryptsoft.com). This product includes software written by Tim |
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* Hudson (tjh@cryptsoft.com). |
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* |
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*/ |
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#include <stdio.h> |
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#include <time.h> |
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#include "cryptlib.h" |
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#include "bn_lcl.h" |
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#include <openssl/rand.h> |
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static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom) |
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{ |
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unsigned char *buf = NULL; |
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int ret = 0, bit, bytes, mask; |
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time_t tim; |
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if (bits < 0 || (bits == 1 && top > 0)) { |
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BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL); |
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return 0; |
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} |
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if (bits == 0) { |
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BN_zero(rnd); |
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return 1; |
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} |
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bytes = (bits + 7) / 8; |
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bit = (bits - 1) % 8; |
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mask = 0xff << (bit + 1); |
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buf = (unsigned char *)OPENSSL_malloc(bytes); |
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if (buf == NULL) { |
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BNerr(BN_F_BNRAND, ERR_R_MALLOC_FAILURE); |
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goto err; |
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} |
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/* make a random number and set the top and bottom bits */ |
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time(&tim); |
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RAND_add(&tim, sizeof(tim), 0.0); |
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/* We ignore the value of pseudorand and always call RAND_bytes */ |
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if (RAND_bytes(buf, bytes) <= 0) |
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goto err; |
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#if 1 |
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if (pseudorand == 2) { |
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/* |
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* generate patterns that are more likely to trigger BN library bugs |
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*/ |
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int i; |
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unsigned char c; |
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for (i = 0; i < bytes; i++) { |
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if (RAND_pseudo_bytes(&c, 1) < 0) |
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goto err; |
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if (c >= 128 && i > 0) |
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buf[i] = buf[i - 1]; |
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else if (c < 42) |
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buf[i] = 0; |
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else if (c < 84) |
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buf[i] = 255; |
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} |
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} |
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#endif |
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if (top >= 0) { |
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if (top) { |
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if (bit == 0) { |
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buf[0] = 1; |
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buf[1] |= 0x80; |
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} else { |
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buf[0] |= (3 << (bit - 1)); |
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} |
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} else { |
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buf[0] |= (1 << bit); |
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} |
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} |
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buf[0] &= ~mask; |
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if (bottom) /* set bottom bit if requested */ |
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buf[bytes - 1] |= 1; |
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if (!BN_bin2bn(buf, bytes, rnd)) |
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goto err; |
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ret = 1; |
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err: |
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if (buf != NULL) { |
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OPENSSL_cleanse(buf, bytes); |
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OPENSSL_free(buf); |
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} |
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bn_check_top(rnd); |
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return (ret); |
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} |
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int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) |
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{ |
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return bnrand(0, rnd, bits, top, bottom); |
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} |
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int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) |
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{ |
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return bnrand(1, rnd, bits, top, bottom); |
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} |
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#if 1 |
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int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom) |
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{ |
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return bnrand(2, rnd, bits, top, bottom); |
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} |
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#endif |
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/* random number r: 0 <= r < range */ |
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static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range) |
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{ |
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int (*bn_rand) (BIGNUM *, int, int, int) = |
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pseudo ? BN_pseudo_rand : BN_rand; |
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int n; |
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int count = 100; |
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if (range->neg || BN_is_zero(range)) { |
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BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE); |
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return 0; |
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} |
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n = BN_num_bits(range); /* n > 0 */ |
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/* BN_is_bit_set(range, n - 1) always holds */ |
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if (n == 1) |
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BN_zero(r); |
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else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) { |
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/* |
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* range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer |
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* than range |
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*/ |
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do { |
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if (!bn_rand(r, n + 1, -1, 0)) |
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return 0; |
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/* |
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* If r < 3*range, use r := r MOD range (which is either r, r - |
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* range, or r - 2*range). Otherwise, iterate once more. Since |
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* 3*range = 11..._2, each iteration succeeds with probability >= |
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* .75. |
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*/ |
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if (BN_cmp(r, range) >= 0) { |
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if (!BN_sub(r, r, range)) |
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return 0; |
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if (BN_cmp(r, range) >= 0) |
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if (!BN_sub(r, r, range)) |
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return 0; |
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} |
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if (!--count) { |
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BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); |
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return 0; |
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} |
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} |
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while (BN_cmp(r, range) >= 0); |
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} else { |
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do { |
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/* range = 11..._2 or range = 101..._2 */ |
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if (!bn_rand(r, n, -1, 0)) |
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return 0; |
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if (!--count) { |
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BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); |
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return 0; |
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} |
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} |
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while (BN_cmp(r, range) >= 0); |
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} |
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bn_check_top(r); |
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return 1; |
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} |
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int BN_rand_range(BIGNUM *r, const BIGNUM *range) |
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{ |
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return bn_rand_range(0, r, range); |
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} |
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int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) |
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{ |
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return bn_rand_range(1, r, range); |
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}
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