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/* $OpenBSD: dsa_gen.c,v 1.24 2017/01/21 10:38:29 beck Exp $ */ |
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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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#include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */ |
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#ifndef OPENSSL_NO_SHA |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <openssl/bn.h> |
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#include <openssl/evp.h> |
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#include <openssl/sha.h> |
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#include "bn_lcl.h" |
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#include "dsa_locl.h" |
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int |
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DSA_generate_parameters_ex(DSA *ret, int bits, const unsigned char *seed_in, |
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int seed_len, int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) |
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{ |
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✗✓ |
20 |
if (ret->meth->dsa_paramgen) |
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return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len, |
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counter_ret, h_ret, cb); |
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else { |
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const EVP_MD *evpmd; |
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size_t qbits; |
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|
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✗✓ |
10 |
if (bits >= 2048) { |
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qbits = 256; |
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evpmd = EVP_sha256(); |
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} else { |
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qbits = 160; |
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evpmd = EVP_sha1(); |
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} |
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return dsa_builtin_paramgen(ret, bits, qbits, evpmd, seed_in, |
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seed_len, NULL, counter_ret, h_ret, cb); |
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} |
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|
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} |
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int |
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dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits, const EVP_MD *evpmd, |
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const unsigned char *seed_in, size_t seed_len, unsigned char *seed_out, |
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int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) |
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{ |
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int ok = 0; |
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unsigned char seed[SHA256_DIGEST_LENGTH]; |
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unsigned char md[SHA256_DIGEST_LENGTH]; |
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unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH]; |
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BIGNUM *r0, *W, *X, *c, *test; |
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BIGNUM *g = NULL, *q = NULL, *p = NULL; |
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BN_MONT_CTX *mont = NULL; |
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int i, k, n = 0, m = 0, qsize = qbits >> 3; |
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int counter = 0; |
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int r = 0; |
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BN_CTX *ctx = NULL; |
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unsigned int h = 2; |
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✗✓ |
24 |
if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH && |
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qsize != SHA256_DIGEST_LENGTH) |
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/* invalid q size */ |
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return 0; |
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✓✓ |
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if (evpmd == NULL) |
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/* use SHA1 as default */ |
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2 |
evpmd = EVP_sha1(); |
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✗✓ |
12 |
if (bits < 512) |
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bits = 512; |
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128 |
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bits = (bits + 63) / 64 * 64; |
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✓✓ |
12 |
if (seed_len < (size_t)qsize) { |
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seed_in = NULL; /* seed buffer too small -- ignore */ |
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seed_len = 0; |
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6 |
} |
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/* |
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* App. 2.2 of FIPS PUB 186 allows larger SEED, |
136 |
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* but our internal buffers are restricted to 160 bits |
137 |
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*/ |
138 |
✗✓ |
12 |
if (seed_len > (size_t)qsize) |
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seed_len = qsize; |
140 |
✓✓ |
12 |
if (seed_in != NULL) |
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memcpy(seed, seed_in, seed_len); |
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✗✓ |
6 |
else if (seed_len != 0) |
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goto err; |
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✗✓ |
12 |
if ((mont=BN_MONT_CTX_new()) == NULL) |
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goto err; |
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✗✓ |
12 |
if ((ctx=BN_CTX_new()) == NULL) |
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goto err; |
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BN_CTX_start(ctx); |
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✗✓ |
12 |
if ((r0 = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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✗✓ |
12 |
if ((g = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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✗✓ |
12 |
if ((W = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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✗✓ |
12 |
if ((q = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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✗✓ |
12 |
if ((X = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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✗✓ |
12 |
if ((c = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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✗✓ |
12 |
if ((p = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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✗✓ |
12 |
if ((test = BN_CTX_get(ctx)) == NULL) |
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goto err; |
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169 |
✗✓ |
12 |
if (!BN_lshift(test, BN_value_one(), bits - 1)) |
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goto err; |
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12 |
for (;;) { |
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for (;;) { /* find q */ |
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int seed_is_random; |
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/* step 1 */ |
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✗✓ |
161 |
if (!BN_GENCB_call(cb, 0, m++)) |
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goto err; |
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180 |
✓✓ |
161 |
if (seed_len == 0) { |
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arc4random_buf(seed, qsize); |
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seed_is_random = 1; |
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} else { |
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seed_is_random = 0; |
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/* use random seed if 'seed_in' turns out |
186 |
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to be bad */ |
187 |
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seed_len = 0; |
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} |
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memcpy(buf, seed, qsize); |
190 |
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161 |
memcpy(buf2, seed, qsize); |
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/* precompute "SEED + 1" for step 7: */ |
192 |
✓✗ |
322 |
for (i = qsize - 1; i >= 0; i--) { |
193 |
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161 |
buf[i]++; |
194 |
✗✓ |
161 |
if (buf[i] != 0) |
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break; |
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} |
197 |
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198 |
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/* step 2 */ |
199 |
✗✓ |
161 |
if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL)) |
200 |
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goto err; |
201 |
✗✓ |
161 |
if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL)) |
202 |
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goto err; |
203 |
✓✓ |
6762 |
for (i = 0; i < qsize; i++) |
204 |
|
3220 |
md[i] ^= buf2[i]; |
205 |
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206 |
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/* step 3 */ |
207 |
|
161 |
md[0] |= 0x80; |
208 |
|
161 |
md[qsize - 1] |= 0x01; |
209 |
✗✓ |
161 |
if (!BN_bin2bn(md, qsize, q)) |
210 |
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goto err; |
211 |
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|
212 |
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/* step 4 */ |
213 |
|
161 |
r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, |
214 |
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seed_is_random, cb); |
215 |
✓✓ |
161 |
if (r > 0) |
216 |
|
12 |
break; |
217 |
✗✓ |
149 |
if (r != 0) |
218 |
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goto err; |
219 |
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|
220 |
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/* do a callback call */ |
221 |
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/* step 5 */ |
222 |
✓✓✓✓
|
149 |
} |
223 |
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|
224 |
✗✓ |
12 |
if (!BN_GENCB_call(cb, 2, 0)) |
225 |
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goto err; |
226 |
✗✓ |
12 |
if (!BN_GENCB_call(cb, 3, 0)) |
227 |
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goto err; |
228 |
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|
229 |
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/* step 6 */ |
230 |
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counter = 0; |
231 |
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/* "offset = 2" */ |
232 |
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|
233 |
|
12 |
n = (bits - 1) / 160; |
234 |
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|
235 |
|
1921 |
for (;;) { |
236 |
✓✓✗✓
|
3830 |
if (counter != 0 && !BN_GENCB_call(cb, 0, counter)) |
237 |
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goto err; |
238 |
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|
239 |
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/* step 7 */ |
240 |
|
1921 |
BN_zero(W); |
241 |
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/* now 'buf' contains "SEED + offset - 1" */ |
242 |
✓✓ |
23350 |
for (k = 0; k <= n; k++) { |
243 |
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/* obtain "SEED + offset + k" by incrementing: */ |
244 |
✓✗ |
19594 |
for (i = qsize - 1; i >= 0; i--) { |
245 |
|
9797 |
buf[i]++; |
246 |
✓✓ |
9797 |
if (buf[i] != 0) |
247 |
|
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break; |
248 |
|
|
} |
249 |
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|
250 |
✗✓ |
9754 |
if (!EVP_Digest(buf, qsize, md ,NULL, evpmd, |
251 |
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|
NULL)) |
252 |
|
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goto err; |
253 |
|
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|
254 |
|
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/* step 8 */ |
255 |
✗✓ |
9754 |
if (!BN_bin2bn(md, qsize, r0)) |
256 |
|
|
goto err; |
257 |
✗✓ |
9754 |
if (!BN_lshift(r0, r0, (qsize << 3) * k)) |
258 |
|
|
goto err; |
259 |
✗✓ |
9754 |
if (!BN_add(W, W, r0)) |
260 |
|
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goto err; |
261 |
|
|
} |
262 |
|
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|
263 |
|
|
/* more of step 8 */ |
264 |
✗✓ |
1921 |
if (!BN_mask_bits(W, bits - 1)) |
265 |
|
|
goto err; |
266 |
✗✓ |
1921 |
if (!BN_copy(X, W)) |
267 |
|
|
goto err; |
268 |
✗✓ |
1921 |
if (!BN_add(X, X, test)) |
269 |
|
|
goto err; |
270 |
|
|
|
271 |
|
|
/* step 9 */ |
272 |
✗✓ |
1921 |
if (!BN_lshift1(r0, q)) |
273 |
|
|
goto err; |
274 |
✗✓ |
1921 |
if (!BN_mod_ct(c, X, r0, ctx)) |
275 |
|
|
goto err; |
276 |
✗✓ |
1921 |
if (!BN_sub(r0, c, BN_value_one())) |
277 |
|
|
goto err; |
278 |
✗✓ |
1921 |
if (!BN_sub(p, X, r0)) |
279 |
|
|
goto err; |
280 |
|
|
|
281 |
|
|
/* step 10 */ |
282 |
✓✗ |
1921 |
if (BN_cmp(p, test) >= 0) { |
283 |
|
|
/* step 11 */ |
284 |
|
1921 |
r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, |
285 |
|
|
ctx, 1, cb); |
286 |
✓✓ |
1921 |
if (r > 0) |
287 |
|
|
goto end; /* found it */ |
288 |
✗✓ |
1909 |
if (r != 0) |
289 |
|
|
goto err; |
290 |
|
|
} |
291 |
|
|
|
292 |
|
|
/* step 13 */ |
293 |
|
1909 |
counter++; |
294 |
|
|
/* "offset = offset + n + 1" */ |
295 |
|
|
|
296 |
|
|
/* step 14 */ |
297 |
✓✗ |
1909 |
if (counter >= 4096) |
298 |
|
|
break; |
299 |
|
|
} |
300 |
|
|
} |
301 |
|
|
end: |
302 |
✗✓ |
12 |
if (!BN_GENCB_call(cb, 2, 1)) |
303 |
|
|
goto err; |
304 |
|
|
|
305 |
|
|
/* We now need to generate g */ |
306 |
|
|
/* Set r0=(p-1)/q */ |
307 |
✗✓ |
12 |
if (!BN_sub(test, p, BN_value_one())) |
308 |
|
|
goto err; |
309 |
✗✓ |
12 |
if (!BN_div_ct(r0, NULL, test, q, ctx)) |
310 |
|
|
goto err; |
311 |
|
|
|
312 |
✗✓ |
12 |
if (!BN_set_word(test, h)) |
313 |
|
|
goto err; |
314 |
✗✓ |
12 |
if (!BN_MONT_CTX_set(mont, p, ctx)) |
315 |
|
|
goto err; |
316 |
|
|
|
317 |
|
12 |
for (;;) { |
318 |
|
|
/* g=test^r0%p */ |
319 |
✗✓ |
12 |
if (!BN_mod_exp_mont_ct(g, test, r0, p, ctx, mont)) |
320 |
|
|
goto err; |
321 |
✗✓✗✗ ✗✗ |
12 |
if (!BN_is_one(g)) |
322 |
|
|
break; |
323 |
|
|
if (!BN_add(test, test, BN_value_one())) |
324 |
|
|
goto err; |
325 |
|
|
h++; |
326 |
|
|
} |
327 |
|
|
|
328 |
✗✓ |
12 |
if (!BN_GENCB_call(cb, 3, 1)) |
329 |
|
|
goto err; |
330 |
|
|
|
331 |
|
12 |
ok = 1; |
332 |
|
|
err: |
333 |
✓✗ |
12 |
if (ok) { |
334 |
|
12 |
BN_free(ret->p); |
335 |
|
12 |
BN_free(ret->q); |
336 |
|
12 |
BN_free(ret->g); |
337 |
|
12 |
ret->p = BN_dup(p); |
338 |
|
12 |
ret->q = BN_dup(q); |
339 |
|
12 |
ret->g = BN_dup(g); |
340 |
✓✗✓✗ ✗✓ |
36 |
if (ret->p == NULL || ret->q == NULL || ret->g == NULL) { |
341 |
|
|
ok = 0; |
342 |
|
|
goto err; |
343 |
|
|
} |
344 |
✓✓ |
12 |
if (counter_ret != NULL) |
345 |
|
6 |
*counter_ret = counter; |
346 |
✓✓ |
12 |
if (h_ret != NULL) |
347 |
|
6 |
*h_ret = h; |
348 |
✗✓ |
12 |
if (seed_out != NULL) |
349 |
|
|
memcpy(seed_out, seed, qsize); |
350 |
|
|
} |
351 |
✓✗ |
12 |
if (ctx) { |
352 |
|
12 |
BN_CTX_end(ctx); |
353 |
|
12 |
BN_CTX_free(ctx); |
354 |
|
12 |
} |
355 |
|
12 |
BN_MONT_CTX_free(mont); |
356 |
|
12 |
return ok; |
357 |
|
12 |
} |
358 |
|
|
#endif |