231 lines
7.3 KiB
C
231 lines
7.3 KiB
C
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/* $OpenBSD: rsa_gen.c,v 1.22 2017/01/29 17:49:23 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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/* NB: these functions have been "upgraded", the deprecated versions (which are
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* compatibility wrappers using these functions) are in rsa_depr.c.
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* - Geoff
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*/
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#include <stdio.h>
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#include <time.h>
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#include <openssl/bn.h>
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#include <openssl/err.h>
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#include <openssl/rsa.h>
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#include "bn_lcl.h"
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static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb);
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/*
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* NB: this wrapper would normally be placed in rsa_lib.c and the static
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* implementation would probably be in rsa_eay.c. Nonetheless, is kept here so
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* that we don't introduce a new linker dependency. Eg. any application that
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* wasn't previously linking object code related to key-generation won't have to
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* now just because key-generation is part of RSA_METHOD.
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*/
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int
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RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
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{
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if (rsa->meth->rsa_keygen)
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return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
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return rsa_builtin_keygen(rsa, bits, e_value, cb);
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}
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static int
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rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
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{
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BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
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BIGNUM pr0, d, p;
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int bitsp, bitsq, ok = -1, n = 0;
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BN_CTX *ctx = NULL;
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ctx = BN_CTX_new();
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if (ctx == NULL)
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goto err;
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BN_CTX_start(ctx);
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if ((r0 = BN_CTX_get(ctx)) == NULL)
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goto err;
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if ((r1 = BN_CTX_get(ctx)) == NULL)
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goto err;
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if ((r2 = BN_CTX_get(ctx)) == NULL)
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goto err;
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if ((r3 = BN_CTX_get(ctx)) == NULL)
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goto err;
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bitsp = (bits + 1) / 2;
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bitsq = bits - bitsp;
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/* We need the RSA components non-NULL */
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if (!rsa->n && ((rsa->n = BN_new()) == NULL))
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goto err;
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if (!rsa->d && ((rsa->d = BN_new()) == NULL))
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goto err;
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if (!rsa->e && ((rsa->e = BN_new()) == NULL))
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goto err;
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if (!rsa->p && ((rsa->p = BN_new()) == NULL))
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goto err;
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if (!rsa->q && ((rsa->q = BN_new()) == NULL))
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goto err;
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if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL))
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goto err;
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if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL))
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goto err;
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if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL))
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goto err;
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BN_copy(rsa->e, e_value);
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/* generate p and q */
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for (;;) {
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if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
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goto err;
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if (!BN_sub(r2, rsa->p, BN_value_one()))
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goto err;
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if (!BN_gcd_ct(r1, r2, rsa->e, ctx))
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goto err;
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if (BN_is_one(r1))
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break;
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if (!BN_GENCB_call(cb, 2, n++))
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goto err;
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}
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if (!BN_GENCB_call(cb, 3, 0))
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goto err;
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for (;;) {
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/*
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* When generating ridiculously small keys, we can get stuck
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* continually regenerating the same prime values. Check for
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* this and bail if it happens 3 times.
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*/
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unsigned int degenerate = 0;
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do {
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if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL,
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cb))
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goto err;
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} while (BN_cmp(rsa->p, rsa->q) == 0 &&
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++degenerate < 3);
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if (degenerate == 3) {
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ok = 0; /* we set our own err */
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RSAerror(RSA_R_KEY_SIZE_TOO_SMALL);
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goto err;
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}
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if (!BN_sub(r2, rsa->q, BN_value_one()))
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goto err;
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if (!BN_gcd_ct(r1, r2, rsa->e, ctx))
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goto err;
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if (BN_is_one(r1))
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break;
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if (!BN_GENCB_call(cb, 2, n++))
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goto err;
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}
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if (!BN_GENCB_call(cb, 3, 1))
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goto err;
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if (BN_cmp(rsa->p, rsa->q) < 0) {
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tmp = rsa->p;
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rsa->p = rsa->q;
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rsa->q = tmp;
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}
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/* calculate n */
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if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))
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goto err;
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/* calculate d */
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if (!BN_sub(r1, rsa->p, BN_value_one())) /* p-1 */
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goto err;
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if (!BN_sub(r2, rsa->q, BN_value_one())) /* q-1 */
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goto err;
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if (!BN_mul(r0, r1, r2, ctx)) /* (p-1)(q-1) */
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goto err;
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BN_with_flags(&pr0, r0, BN_FLG_CONSTTIME);
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if (!BN_mod_inverse_ct(rsa->d, rsa->e, &pr0, ctx)) /* d */
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goto err;
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/* set up d for correct BN_FLG_CONSTTIME flag */
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BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME);
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/* calculate d mod (p-1) */
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if (!BN_mod_ct(rsa->dmp1, &d, r1, ctx))
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goto err;
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/* calculate d mod (q-1) */
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if (!BN_mod_ct(rsa->dmq1, &d, r2, ctx))
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goto err;
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/* calculate inverse of q mod p */
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BN_with_flags(&p, rsa->p, BN_FLG_CONSTTIME);
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if (!BN_mod_inverse_ct(rsa->iqmp, rsa->q, &p, ctx))
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goto err;
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ok = 1;
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err:
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if (ok == -1) {
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RSAerror(ERR_LIB_BN);
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ok = 0;
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}
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if (ctx != NULL) {
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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}
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return ok;
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}
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