2 * Copyright 1998-2018 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #include <openssl/opensslconf.h>
11 #include "internal/cryptlib.h"
14 #define BN_BLINDING_COUNTER 32
16 struct bn_blinding_st {
20 BIGNUM *mod; /* just a reference */
25 int (*bn_mod_exp) (BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
26 const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
30 BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)
32 BN_BLINDING *ret = NULL;
36 if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
37 BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE);
41 ret->lock = CRYPTO_THREAD_lock_new();
42 if (ret->lock == NULL) {
43 BNerr(BN_F_BN_BLINDING_NEW, ERR_R_MALLOC_FAILURE);
48 BN_BLINDING_set_current_thread(ret);
51 if ((ret->A = BN_dup(A)) == NULL)
56 if ((ret->Ai = BN_dup(Ai)) == NULL)
60 /* save a copy of mod in the BN_BLINDING structure */
61 if ((ret->mod = BN_dup(mod)) == NULL)
64 if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
65 BN_set_flags(ret->mod, BN_FLG_CONSTTIME);
68 * Set the counter to the special value -1 to indicate that this is
69 * never-used fresh blinding that does not need updating before first
77 BN_BLINDING_free(ret);
81 void BN_BLINDING_free(BN_BLINDING *r)
89 CRYPTO_THREAD_lock_free(r->lock);
93 int BN_BLINDING_update(BN_BLINDING *b, BN_CTX *ctx)
97 if ((b->A == NULL) || (b->Ai == NULL)) {
98 BNerr(BN_F_BN_BLINDING_UPDATE, BN_R_NOT_INITIALIZED);
102 if (b->counter == -1)
105 if (++b->counter == BN_BLINDING_COUNTER && b->e != NULL &&
106 !(b->flags & BN_BLINDING_NO_RECREATE)) {
107 /* re-create blinding parameters */
108 if (!BN_BLINDING_create_param(b, NULL, NULL, ctx, NULL, NULL))
110 } else if (!(b->flags & BN_BLINDING_NO_UPDATE)) {
111 if (b->m_ctx != NULL) {
112 if (!bn_mul_mont_fixed_top(b->Ai, b->Ai, b->Ai, b->m_ctx, ctx)
113 || !bn_mul_mont_fixed_top(b->A, b->A, b->A, b->m_ctx, ctx))
116 if (!BN_mod_mul(b->Ai, b->Ai, b->Ai, b->mod, ctx)
117 || !BN_mod_mul(b->A, b->A, b->A, b->mod, ctx))
124 if (b->counter == BN_BLINDING_COUNTER)
129 int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
131 return BN_BLINDING_convert_ex(n, NULL, b, ctx);
134 int BN_BLINDING_convert_ex(BIGNUM *n, BIGNUM *r, BN_BLINDING *b, BN_CTX *ctx)
140 if ((b->A == NULL) || (b->Ai == NULL)) {
141 BNerr(BN_F_BN_BLINDING_CONVERT_EX, BN_R_NOT_INITIALIZED);
145 if (b->counter == -1)
146 /* Fresh blinding, doesn't need updating. */
148 else if (!BN_BLINDING_update(b, ctx))
151 if (r != NULL && (BN_copy(r, b->Ai) == NULL))
154 if (b->m_ctx != NULL)
155 ret = BN_mod_mul_montgomery(n, n, b->A, b->m_ctx, ctx);
157 ret = BN_mod_mul(n, n, b->A, b->mod, ctx);
162 int BN_BLINDING_invert(BIGNUM *n, BN_BLINDING *b, BN_CTX *ctx)
164 return BN_BLINDING_invert_ex(n, NULL, b, ctx);
167 int BN_BLINDING_invert_ex(BIGNUM *n, const BIGNUM *r, BN_BLINDING *b,
174 if (r == NULL && (r = b->Ai) == NULL) {
175 BNerr(BN_F_BN_BLINDING_INVERT_EX, BN_R_NOT_INITIALIZED);
179 if (b->m_ctx != NULL) {
180 /* ensure that BN_mod_mul_montgomery takes pre-defined path */
181 if (n->dmax >= r->top) {
182 size_t i, rtop = r->top, ntop = n->top;
185 for (i = 0; i < rtop; i++) {
186 mask = (BN_ULONG)0 - ((i - ntop) >> (8 * sizeof(i) - 1));
189 mask = (BN_ULONG)0 - ((rtop - ntop) >> (8 * sizeof(ntop) - 1));
190 /* always true, if (rtop >= ntop) n->top = r->top; */
191 n->top = (int)(rtop & ~mask) | (ntop & mask);
192 n->flags |= (BN_FLG_FIXED_TOP & ~mask);
194 ret = BN_mod_mul_montgomery(n, n, r, b->m_ctx, ctx);
196 ret = BN_mod_mul(n, n, r, b->mod, ctx);
203 int BN_BLINDING_is_current_thread(BN_BLINDING *b)
205 return CRYPTO_THREAD_compare_id(CRYPTO_THREAD_get_current_id(), b->tid);
208 void BN_BLINDING_set_current_thread(BN_BLINDING *b)
210 b->tid = CRYPTO_THREAD_get_current_id();
213 int BN_BLINDING_lock(BN_BLINDING *b)
215 return CRYPTO_THREAD_write_lock(b->lock);
218 int BN_BLINDING_unlock(BN_BLINDING *b)
220 return CRYPTO_THREAD_unlock(b->lock);
223 unsigned long BN_BLINDING_get_flags(const BN_BLINDING *b)
228 void BN_BLINDING_set_flags(BN_BLINDING *b, unsigned long flags)
233 BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
234 const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
235 int (*bn_mod_exp) (BIGNUM *r,
243 int retry_counter = 32;
244 BN_BLINDING *ret = NULL;
247 ret = BN_BLINDING_new(NULL, NULL, m);
254 if (ret->A == NULL && (ret->A = BN_new()) == NULL)
256 if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
266 if (bn_mod_exp != NULL)
267 ret->bn_mod_exp = bn_mod_exp;
273 if (!BN_priv_rand_range(ret->A, ret->mod))
275 if (int_bn_mod_inverse(ret->Ai, ret->A, ret->mod, ctx, &rv))
279 * this should almost never happen for good RSA keys
284 if (retry_counter-- == 0) {
285 BNerr(BN_F_BN_BLINDING_CREATE_PARAM, BN_R_TOO_MANY_ITERATIONS);
290 if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) {
291 if (!ret->bn_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
294 if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
298 if (ret->m_ctx != NULL) {
299 if (!bn_to_mont_fixed_top(ret->Ai, ret->Ai, ret->m_ctx, ctx)
300 || !bn_to_mont_fixed_top(ret->A, ret->A, ret->m_ctx, ctx))
307 BN_BLINDING_free(ret);