312 lines
7.9 KiB
C
312 lines
7.9 KiB
C
/*
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* Copyright 1998-2023 The OpenSSL Project Authors. 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/opensslconf.h>
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#include "internal/cryptlib.h"
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#include "bn_local.h"
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#define BN_BLINDING_COUNTER 32
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struct bn_blinding_st {
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BIGNUM *A;
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BIGNUM *Ai;
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BIGNUM *e;
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BIGNUM *mod; /* just a reference */
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CRYPTO_THREAD_ID tid;
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int counter;
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unsigned long flags;
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BN_MONT_CTX *m_ctx;
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int (*bn_mod_exp) (BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
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const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
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CRYPTO_RWLOCK *lock;
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};
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BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)
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{
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BN_BLINDING *ret = NULL;
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bn_check_top(mod);
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if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL)
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return NULL;
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ret->lock = CRYPTO_THREAD_lock_new();
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if (ret->lock == NULL) {
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ERR_raise(ERR_LIB_BN, ERR_R_CRYPTO_LIB);
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OPENSSL_free(ret);
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return NULL;
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}
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BN_BLINDING_set_current_thread(ret);
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if (A != NULL) {
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if ((ret->A = BN_dup(A)) == NULL)
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goto err;
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}
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if (Ai != NULL) {
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if ((ret->Ai = BN_dup(Ai)) == NULL)
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goto err;
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}
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/* save a copy of mod in the BN_BLINDING structure */
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if ((ret->mod = BN_dup(mod)) == NULL)
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goto err;
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if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
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BN_set_flags(ret->mod, BN_FLG_CONSTTIME);
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/*
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* Set the counter to the special value -1 to indicate that this is
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* never-used fresh blinding that does not need updating before first
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* use.
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*/
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ret->counter = -1;
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return ret;
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err:
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BN_BLINDING_free(ret);
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return NULL;
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}
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void BN_BLINDING_free(BN_BLINDING *r)
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{
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if (r == NULL)
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return;
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BN_free(r->A);
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BN_free(r->Ai);
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BN_free(r->e);
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BN_free(r->mod);
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CRYPTO_THREAD_lock_free(r->lock);
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OPENSSL_free(r);
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}
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int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
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{
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int ret = 0;
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if ((b->A == NULL) || (b->Ai == NULL)) {
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ERR_raise(ERR_LIB_BN, BN_R_NOT_INITIALIZED);
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goto err;
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}
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if (b->counter == -1)
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b->counter = 0;
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if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL &&
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!(b->flags & BN_BLINDING_NO_RECREATE)) {
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/* re-create blinding parameters */
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if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
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goto err;
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} else if (!(b->flags & BN_BLINDING_NO_UPDATE)) {
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if (b->m_ctx != NULL) {
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if (!bn_mul_mont_fixed_top(b->Ai, b->Ai, b->Ai, b->m_ctx, ctx)
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|| !bn_mul_mont_fixed_top(b->A, b->A, b->A, b->m_ctx, ctx))
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goto err;
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} else {
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if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx)
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|| !BN_mod_mul(b->A, b->A, b->A, b->mod, ctx))
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goto err;
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}
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}
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ret = 1;
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err:
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if (b->counter == BN_BLINDING_COUNTER)
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b->counter = 0;
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return ret;
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}
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int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
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{
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return BN_BLINDING_convert_ex(n, NULL, b, ctx);
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}
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int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
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{
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int ret = 1;
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bn_check_top(n);
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if ((b->A == NULL) || (b->Ai == NULL)) {
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ERR_raise(ERR_LIB_BN, BN_R_NOT_INITIALIZED);
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return 0;
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}
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if (b->counter == -1)
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/* Fresh blinding, doesn't need updating. */
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b->counter = 0;
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else if (!BN_BLINDING_update(b, ctx))
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return 0;
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if (r != NULL && (BN_copy(r, b->Ai) == NULL))
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return 0;
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if (b->m_ctx != NULL)
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ret = BN_mod_mul_montgomery(n, n, b->A, b->m_ctx, ctx);
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else
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ret = BN_mod_mul(n, n, b->A, b->mod, ctx);
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return ret;
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}
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int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
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{
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return BN_BLINDING_invert_ex(n, NULL, b, ctx);
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}
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int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b,
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BN_CTX *ctx)
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{
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int ret;
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bn_check_top(n);
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if (r == NULL && (r = b->Ai) == NULL) {
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ERR_raise(ERR_LIB_BN, BN_R_NOT_INITIALIZED);
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return 0;
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}
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if (b->m_ctx != NULL) {
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/* ensure that BN_mod_mul_montgomery takes pre-defined path */
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if (n->dmax >= r->top) {
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size_t i, rtop = r->top, ntop = n->top;
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BN_ULONG mask;
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for (i = 0; i < rtop; i++) {
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mask = (BN_ULONG)0 - ((i - ntop) >> (8 * sizeof(i) - 1));
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n->d[i] &= mask;
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}
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mask = (BN_ULONG)0 - ((rtop - ntop) >> (8 * sizeof(ntop) - 1));
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/* always true, if (rtop >= ntop) n->top = r->top; */
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n->top = (int)(rtop & ~mask) | (ntop & mask);
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n->flags |= (BN_FLG_FIXED_TOP & ~mask);
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}
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ret = bn_mul_mont_fixed_top(n, n, r, b->m_ctx, ctx);
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bn_correct_top_consttime(n);
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} else {
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ret = BN_mod_mul(n, n, r, b->mod, ctx);
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}
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bn_check_top(n);
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return ret;
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}
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int BN_BLINDING_is_current_thread(BN_BLINDING *b)
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{
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return CRYPTO_THREAD_compare_id(CRYPTO_THREAD_get_current_id(), b->tid);
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}
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void BN_BLINDING_set_current_thread(BN_BLINDING *b)
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{
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b->tid = CRYPTO_THREAD_get_current_id();
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}
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int BN_BLINDING_lock(BN_BLINDING *b)
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{
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return CRYPTO_THREAD_write_lock(b->lock);
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}
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int BN_BLINDING_unlock(BN_BLINDING *b)
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{
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return CRYPTO_THREAD_unlock(b->lock);
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}
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unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
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{
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return b->flags;
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}
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void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
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{
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b->flags = flags;
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}
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BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
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const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
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int (*bn_mod_exp) (BIGNUM *r,
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const BIGNUM *a,
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const BIGNUM *p,
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const BIGNUM *m,
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BN_CTX *ctx,
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BN_MONT_CTX *m_ctx),
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BN_MONT_CTX *m_ctx)
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{
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int retry_counter = 32;
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BN_BLINDING *ret = NULL;
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if (b == NULL)
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ret = BN_BLINDING_new(NULL, NULL, m);
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else
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ret = b;
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if (ret == NULL)
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goto err;
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if (ret->A == NULL && (ret->A = BN_new()) == NULL)
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goto err;
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if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
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goto err;
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if (e != NULL) {
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BN_free(ret->e);
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ret->e = BN_dup(e);
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}
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if (ret->e == NULL)
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goto err;
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if (bn_mod_exp != NULL)
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ret->bn_mod_exp = bn_mod_exp;
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if (m_ctx != NULL)
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ret->m_ctx = m_ctx;
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do {
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int rv;
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if (!BN_priv_rand_range_ex(ret->A, ret->mod, 0, ctx))
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goto err;
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if (int_bn_mod_inverse(ret->Ai, ret->A, ret->mod, ctx, &rv))
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break;
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/*
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* this should almost never happen for good RSA keys
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*/
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if (!rv)
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goto err;
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if (retry_counter-- == 0) {
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ERR_raise(ERR_LIB_BN, BN_R_TOO_MANY_ITERATIONS);
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goto err;
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}
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} while (1);
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if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) {
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if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
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goto err;
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} else {
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if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
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goto err;
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}
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if (ret->m_ctx != NULL) {
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if (!bn_to_mont_fixed_top(ret->Ai, ret->Ai, ret->m_ctx, ctx)
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|| !bn_to_mont_fixed_top(ret->A, ret->A, ret->m_ctx, ctx))
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goto err;
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}
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return ret;
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err:
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if (b == NULL) {
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BN_BLINDING_free(ret);
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ret = NULL;
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}
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return ret;
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}
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