mirror of https://github.com/openssl/openssl
449 lines
13 KiB
C
449 lines
13 KiB
C
/*
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* Copyright 2018-2024 The OpenSSL Project Authors. All Rights Reserved.
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* Copyright (c) 2018-2019, Oracle and/or its affiliates. All rights reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <openssl/err.h>
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#include <openssl/bn.h>
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#include "crypto/bn.h"
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#include "rsa_local.h"
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/*
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* Part of the RSA keypair test.
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* Check the Chinese Remainder Theorem components are valid.
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*
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* See SP800-5bBr1
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* 6.4.1.2.3: rsakpv1-crt Step 7
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* 6.4.1.3.3: rsakpv2-crt Step 7
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*/
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int ossl_rsa_check_crt_components(const RSA *rsa, BN_CTX *ctx)
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{
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int ret = 0;
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BIGNUM *r = NULL, *p1 = NULL, *q1 = NULL;
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/* check if only some of the crt components are set */
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if (rsa->dmp1 == NULL || rsa->dmq1 == NULL || rsa->iqmp == NULL) {
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if (rsa->dmp1 != NULL || rsa->dmq1 != NULL || rsa->iqmp != NULL)
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return 0;
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return 1; /* return ok if all components are NULL */
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}
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BN_CTX_start(ctx);
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r = BN_CTX_get(ctx);
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p1 = BN_CTX_get(ctx);
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q1 = BN_CTX_get(ctx);
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if (q1 != NULL) {
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BN_set_flags(r, BN_FLG_CONSTTIME);
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BN_set_flags(p1, BN_FLG_CONSTTIME);
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BN_set_flags(q1, BN_FLG_CONSTTIME);
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ret = 1;
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} else {
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ret = 0;
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}
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ret = ret
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/* p1 = p -1 */
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&& (BN_copy(p1, rsa->p) != NULL)
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&& BN_sub_word(p1, 1)
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/* q1 = q - 1 */
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&& (BN_copy(q1, rsa->q) != NULL)
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&& BN_sub_word(q1, 1)
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/* (a) 1 < dP < (p – 1). */
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&& (BN_cmp(rsa->dmp1, BN_value_one()) > 0)
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&& (BN_cmp(rsa->dmp1, p1) < 0)
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/* (b) 1 < dQ < (q - 1). */
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&& (BN_cmp(rsa->dmq1, BN_value_one()) > 0)
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&& (BN_cmp(rsa->dmq1, q1) < 0)
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/* (c) 1 < qInv < p */
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&& (BN_cmp(rsa->iqmp, BN_value_one()) > 0)
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&& (BN_cmp(rsa->iqmp, rsa->p) < 0)
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/* (d) 1 = (dP . e) mod (p - 1)*/
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&& BN_mod_mul(r, rsa->dmp1, rsa->e, p1, ctx)
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&& BN_is_one(r)
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/* (e) 1 = (dQ . e) mod (q - 1) */
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&& BN_mod_mul(r, rsa->dmq1, rsa->e, q1, ctx)
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&& BN_is_one(r)
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/* (f) 1 = (qInv . q) mod p */
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&& BN_mod_mul(r, rsa->iqmp, rsa->q, rsa->p, ctx)
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&& BN_is_one(r);
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BN_clear(r);
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BN_clear(p1);
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BN_clear(q1);
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BN_CTX_end(ctx);
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return ret;
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}
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/*
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* Part of the RSA keypair test.
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* Check that (√2)(2^(nbits/2 - 1) <= p <= 2^(nbits/2) - 1
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*
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* See SP800-5bBr1 6.4.1.2.1 Part 5 (c) & (g) - used for both p and q.
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*
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* (√2)(2^(nbits/2 - 1) = (√2/2)(2^(nbits/2))
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*/
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int ossl_rsa_check_prime_factor_range(const BIGNUM *p, int nbits, BN_CTX *ctx)
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{
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int ret = 0;
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BIGNUM *low;
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int shift;
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nbits >>= 1;
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shift = nbits - BN_num_bits(&ossl_bn_inv_sqrt_2);
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/* Upper bound check */
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if (BN_num_bits(p) != nbits)
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return 0;
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BN_CTX_start(ctx);
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low = BN_CTX_get(ctx);
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if (low == NULL)
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goto err;
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/* set low = (√2)(2^(nbits/2 - 1) */
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if (!BN_copy(low, &ossl_bn_inv_sqrt_2))
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goto err;
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if (shift >= 0) {
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/*
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* We don't have all the bits. ossl_bn_inv_sqrt_2 contains a rounded up
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* value, so there is a very low probability that we'll reject a valid
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* value.
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*/
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if (!BN_lshift(low, low, shift))
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goto err;
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} else if (!BN_rshift(low, low, -shift)) {
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goto err;
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}
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if (BN_cmp(p, low) <= 0)
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goto err;
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ret = 1;
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err:
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BN_CTX_end(ctx);
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return ret;
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}
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/*
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* Part of the RSA keypair test.
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* Check the prime factor (for either p or q)
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* i.e: p is prime AND GCD(p - 1, e) = 1
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*
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* See SP800-56Br1 6.4.1.2.3 Step 5 (a to d) & (e to h).
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*/
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int ossl_rsa_check_prime_factor(BIGNUM *p, BIGNUM *e, int nbits, BN_CTX *ctx)
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{
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int ret = 0;
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BIGNUM *p1 = NULL, *gcd = NULL;
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/* (Steps 5 a-b) prime test */
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if (BN_check_prime(p, ctx, NULL) != 1
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/* (Step 5c) (√2)(2^(nbits/2 - 1) <= p <= 2^(nbits/2 - 1) */
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|| ossl_rsa_check_prime_factor_range(p, nbits, ctx) != 1)
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return 0;
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BN_CTX_start(ctx);
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p1 = BN_CTX_get(ctx);
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gcd = BN_CTX_get(ctx);
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if (gcd != NULL) {
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BN_set_flags(p1, BN_FLG_CONSTTIME);
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BN_set_flags(gcd, BN_FLG_CONSTTIME);
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ret = 1;
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} else {
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ret = 0;
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}
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ret = ret
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/* (Step 5d) GCD(p-1, e) = 1 */
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&& (BN_copy(p1, p) != NULL)
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&& BN_sub_word(p1, 1)
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&& BN_gcd(gcd, p1, e, ctx)
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&& BN_is_one(gcd);
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BN_clear(p1);
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BN_CTX_end(ctx);
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return ret;
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}
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/*
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* See SP800-56Br1 6.4.1.2.3 Part 6(a-b) Check the private exponent d
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* satisfies:
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* (Step 6a) 2^(nBit/2) < d < LCM(p–1, q–1).
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* (Step 6b) 1 = (d*e) mod LCM(p–1, q–1)
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*/
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int ossl_rsa_check_private_exponent(const RSA *rsa, int nbits, BN_CTX *ctx)
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{
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int ret;
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BIGNUM *r, *p1, *q1, *lcm, *p1q1, *gcd;
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/* (Step 6a) 2^(nbits/2) < d */
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if (BN_num_bits(rsa->d) <= (nbits >> 1))
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return 0;
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BN_CTX_start(ctx);
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r = BN_CTX_get(ctx);
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p1 = BN_CTX_get(ctx);
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q1 = BN_CTX_get(ctx);
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lcm = BN_CTX_get(ctx);
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p1q1 = BN_CTX_get(ctx);
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gcd = BN_CTX_get(ctx);
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if (gcd != NULL) {
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BN_set_flags(r, BN_FLG_CONSTTIME);
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BN_set_flags(p1, BN_FLG_CONSTTIME);
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BN_set_flags(q1, BN_FLG_CONSTTIME);
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BN_set_flags(lcm, BN_FLG_CONSTTIME);
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BN_set_flags(p1q1, BN_FLG_CONSTTIME);
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BN_set_flags(gcd, BN_FLG_CONSTTIME);
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ret = 1;
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} else {
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ret = 0;
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}
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ret = (ret
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/* LCM(p - 1, q - 1) */
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&& (ossl_rsa_get_lcm(ctx, rsa->p, rsa->q, lcm, gcd, p1, q1,
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p1q1) == 1)
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/* (Step 6a) d < LCM(p - 1, q - 1) */
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&& (BN_cmp(rsa->d, lcm) < 0)
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/* (Step 6b) 1 = (e . d) mod LCM(p - 1, q - 1) */
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&& BN_mod_mul(r, rsa->e, rsa->d, lcm, ctx)
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&& BN_is_one(r));
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BN_clear(r);
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BN_clear(p1);
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BN_clear(q1);
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BN_clear(lcm);
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BN_clear(gcd);
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BN_CTX_end(ctx);
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return ret;
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}
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/*
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* Check exponent is odd.
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* For FIPS also check the bit length is in the range [17..256]
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*/
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int ossl_rsa_check_public_exponent(const BIGNUM *e)
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{
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#ifdef FIPS_MODULE
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int bitlen;
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bitlen = BN_num_bits(e);
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return (BN_is_odd(e) && bitlen > 16 && bitlen < 257);
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#else
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/* Allow small exponents larger than 1 for legacy purposes */
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return BN_is_odd(e) && BN_cmp(e, BN_value_one()) > 0;
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#endif /* FIPS_MODULE */
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}
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/*
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* SP800-56Br1 6.4.1.2.1 (Step 5i): |p - q| > 2^(nbits/2 - 100)
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* i.e- numbits(p-q-1) > (nbits/2 -100)
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*/
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int ossl_rsa_check_pminusq_diff(BIGNUM *diff, const BIGNUM *p, const BIGNUM *q,
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int nbits)
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{
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int bitlen = (nbits >> 1) - 100;
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if (!BN_sub(diff, p, q))
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return -1;
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BN_set_negative(diff, 0);
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if (BN_is_zero(diff))
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return 0;
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if (!BN_sub_word(diff, 1))
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return -1;
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return (BN_num_bits(diff) > bitlen);
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}
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/*
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* return LCM(p-1, q-1)
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*
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* Caller should ensure that lcm, gcd, p1, q1, p1q1 are flagged with
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* BN_FLG_CONSTTIME.
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*/
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int ossl_rsa_get_lcm(BN_CTX *ctx, const BIGNUM *p, const BIGNUM *q,
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BIGNUM *lcm, BIGNUM *gcd, BIGNUM *p1, BIGNUM *q1,
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BIGNUM *p1q1)
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{
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return BN_sub(p1, p, BN_value_one()) /* p-1 */
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&& BN_sub(q1, q, BN_value_one()) /* q-1 */
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&& BN_mul(p1q1, p1, q1, ctx) /* (p-1)(q-1) */
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&& BN_gcd(gcd, p1, q1, ctx)
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&& BN_div(lcm, NULL, p1q1, gcd, ctx); /* LCM((p-1, q-1)) */
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}
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/*
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* SP800-56Br1 6.4.2.2 Partial Public Key Validation for RSA refers to
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* SP800-89 5.3.3 (Explicit) Partial Public Key Validation for RSA
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* caveat is that the modulus must be as specified in SP800-56Br1
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*/
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int ossl_rsa_sp800_56b_check_public(const RSA *rsa)
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{
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int ret = 0, status;
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int nbits;
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BN_CTX *ctx = NULL;
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BIGNUM *gcd = NULL;
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if (rsa->n == NULL || rsa->e == NULL)
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return 0;
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nbits = BN_num_bits(rsa->n);
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if (nbits > OPENSSL_RSA_MAX_MODULUS_BITS) {
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ERR_raise(ERR_LIB_RSA, RSA_R_MODULUS_TOO_LARGE);
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return 0;
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}
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#ifdef FIPS_MODULE
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/*
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* (Step a): modulus must be 2048 or 3072 (caveat from SP800-56Br1)
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* NOTE: changed to allow keys >= 2048
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*/
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if (!ossl_rsa_sp800_56b_validate_strength(nbits, -1)) {
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_KEY_LENGTH);
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return 0;
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}
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#endif
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if (!BN_is_odd(rsa->n)) {
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_MODULUS);
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return 0;
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}
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/* (Steps b-c): 2^16 < e < 2^256, n and e must be odd */
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if (!ossl_rsa_check_public_exponent(rsa->e)) {
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ERR_raise(ERR_LIB_RSA, RSA_R_PUB_EXPONENT_OUT_OF_RANGE);
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return 0;
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}
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ctx = BN_CTX_new_ex(rsa->libctx);
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gcd = BN_new();
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if (ctx == NULL || gcd == NULL)
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goto err;
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/* (Steps d-f):
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* The modulus is composite, but not a power of a prime.
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* The modulus has no factors smaller than 752.
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*/
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if (!BN_gcd(gcd, rsa->n, ossl_bn_get0_small_factors(), ctx)
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|| !BN_is_one(gcd)) {
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_MODULUS);
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goto err;
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}
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/* Highest number of MR rounds from FIPS 186-5 Section B.3 Table B.1 */
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ret = ossl_bn_miller_rabin_is_prime(rsa->n, 5, ctx, NULL, 1, &status);
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#ifdef FIPS_MODULE
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if (ret != 1 || status != BN_PRIMETEST_COMPOSITE_NOT_POWER_OF_PRIME) {
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#else
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if (ret != 1 || (status != BN_PRIMETEST_COMPOSITE_NOT_POWER_OF_PRIME
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&& (nbits >= RSA_MIN_MODULUS_BITS
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|| status != BN_PRIMETEST_COMPOSITE_WITH_FACTOR))) {
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#endif
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_MODULUS);
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ret = 0;
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goto err;
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}
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ret = 1;
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err:
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BN_free(gcd);
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BN_CTX_free(ctx);
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return ret;
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}
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/*
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* Perform validation of the RSA private key to check that 0 < D < N.
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*/
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int ossl_rsa_sp800_56b_check_private(const RSA *rsa)
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{
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if (rsa->d == NULL || rsa->n == NULL)
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return 0;
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return BN_cmp(rsa->d, BN_value_one()) >= 0 && BN_cmp(rsa->d, rsa->n) < 0;
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}
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/*
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* RSA key pair validation.
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*
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* SP800-56Br1.
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* 6.4.1.2 "RSAKPV1 Family: RSA Key - Pair Validation with a Fixed Exponent"
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* 6.4.1.3 "RSAKPV2 Family: RSA Key - Pair Validation with a Random Exponent"
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*
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* It uses:
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* 6.4.1.2.3 "rsakpv1 - crt"
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* 6.4.1.3.3 "rsakpv2 - crt"
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*/
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int ossl_rsa_sp800_56b_check_keypair(const RSA *rsa, const BIGNUM *efixed,
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int strength, int nbits)
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{
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int ret = 0;
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BN_CTX *ctx = NULL;
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BIGNUM *r = NULL;
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if (rsa->p == NULL
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|| rsa->q == NULL
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|| rsa->e == NULL
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|| rsa->d == NULL
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|| rsa->n == NULL) {
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_REQUEST);
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return 0;
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}
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/* (Step 1): Check Ranges */
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if (!ossl_rsa_sp800_56b_validate_strength(nbits, strength))
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return 0;
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/* If the exponent is known */
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if (efixed != NULL) {
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/* (2): Check fixed exponent matches public exponent. */
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if (BN_cmp(efixed, rsa->e) != 0) {
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_REQUEST);
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return 0;
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}
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}
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/* (Step 1.c): e is odd integer 65537 <= e < 2^256 */
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if (!ossl_rsa_check_public_exponent(rsa->e)) {
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/* exponent out of range */
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ERR_raise(ERR_LIB_RSA, RSA_R_PUB_EXPONENT_OUT_OF_RANGE);
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return 0;
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}
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/* (Step 3.b): check the modulus */
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if (nbits != BN_num_bits(rsa->n)) {
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_KEYPAIR);
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return 0;
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}
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/* (Step 3.c): check that the modulus length is a positive even integer */
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if (nbits <= 0 || (nbits & 0x1)) {
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_KEYPAIR);
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return 0;
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}
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ctx = BN_CTX_new_ex(rsa->libctx);
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if (ctx == NULL)
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return 0;
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BN_CTX_start(ctx);
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r = BN_CTX_get(ctx);
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if (r == NULL || !BN_mul(r, rsa->p, rsa->q, ctx))
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goto err;
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/* (Step 4.c): Check n = pq */
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if (BN_cmp(rsa->n, r) != 0) {
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_REQUEST);
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goto err;
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}
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/* (Step 5): check prime factors p & q */
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ret = ossl_rsa_check_prime_factor(rsa->p, rsa->e, nbits, ctx)
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&& ossl_rsa_check_prime_factor(rsa->q, rsa->e, nbits, ctx)
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&& (ossl_rsa_check_pminusq_diff(r, rsa->p, rsa->q, nbits) > 0)
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/* (Step 6): Check the private exponent d */
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&& ossl_rsa_check_private_exponent(rsa, nbits, ctx)
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/* 6.4.1.2.3 (Step 7): Check the CRT components */
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&& ossl_rsa_check_crt_components(rsa, ctx);
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if (ret != 1)
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ERR_raise(ERR_LIB_RSA, RSA_R_INVALID_KEYPAIR);
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err:
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BN_clear(r);
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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return ret;
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}
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