ref: bfe9da47cfa2f51ebef78c59332b5ba2deba306d
dir: /third_party/boringssl/src/crypto/fipsmodule/rsa/blinding.c/
/* ====================================================================
* Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@openssl.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/rsa.h>
#include <string.h>
#include <openssl/bn.h>
#include <openssl/mem.h>
#include <openssl/err.h>
#include "internal.h"
#include "../../internal.h"
#define BN_BLINDING_COUNTER 32
struct bn_blinding_st {
BIGNUM *A; // The base blinding factor, Montgomery-encoded.
BIGNUM *Ai; // The inverse of the blinding factor, Montgomery-encoded.
unsigned counter;
};
static int bn_blinding_create_param(BN_BLINDING *b, const BIGNUM *e,
const BN_MONT_CTX *mont, BN_CTX *ctx);
BN_BLINDING *BN_BLINDING_new(void) {
BN_BLINDING *ret = OPENSSL_malloc(sizeof(BN_BLINDING));
if (ret == NULL) {
OPENSSL_PUT_ERROR(RSA, ERR_R_MALLOC_FAILURE);
return NULL;
}
OPENSSL_memset(ret, 0, sizeof(BN_BLINDING));
ret->A = BN_new();
if (ret->A == NULL) {
goto err;
}
ret->Ai = BN_new();
if (ret->Ai == NULL) {
goto err;
}
// The blinding values need to be created before this blinding can be used.
ret->counter = BN_BLINDING_COUNTER - 1;
return ret;
err:
BN_BLINDING_free(ret);
return NULL;
}
void BN_BLINDING_free(BN_BLINDING *r) {
if (r == NULL) {
return;
}
BN_free(r->A);
BN_free(r->Ai);
OPENSSL_free(r);
}
void BN_BLINDING_invalidate(BN_BLINDING *b) {
b->counter = BN_BLINDING_COUNTER - 1;
}
static int bn_blinding_update(BN_BLINDING *b, const BIGNUM *e,
const BN_MONT_CTX *mont, BN_CTX *ctx) {
if (++b->counter == BN_BLINDING_COUNTER) {
// re-create blinding parameters
if (!bn_blinding_create_param(b, e, mont, ctx)) {
goto err;
}
b->counter = 0;
} else {
if (!BN_mod_mul_montgomery(b->A, b->A, b->A, mont, ctx) ||
!BN_mod_mul_montgomery(b->Ai, b->Ai, b->Ai, mont, ctx)) {
goto err;
}
}
return 1;
err:
// |A| and |Ai| may be in an inconsistent state so they both need to be
// replaced the next time this blinding is used. Note that this is only
// sufficient because support for |BN_BLINDING_NO_UPDATE| and
// |BN_BLINDING_NO_RECREATE| was previously dropped.
b->counter = BN_BLINDING_COUNTER - 1;
return 0;
}
int BN_BLINDING_convert(BIGNUM *n, BN_BLINDING *b, const BIGNUM *e,
const BN_MONT_CTX *mont, BN_CTX *ctx) {
// |n| is not Montgomery-encoded and |b->A| is. |BN_mod_mul_montgomery|
// cancels one Montgomery factor, so the resulting value of |n| is unencoded.
if (!bn_blinding_update(b, e, mont, ctx) ||
!BN_mod_mul_montgomery(n, n, b->A, mont, ctx)) {
return 0;
}
return 1;
}
int BN_BLINDING_invert(BIGNUM *n, const BN_BLINDING *b, BN_MONT_CTX *mont,
BN_CTX *ctx) {
// |n| is not Montgomery-encoded and |b->A| is. |BN_mod_mul_montgomery|
// cancels one Montgomery factor, so the resulting value of |n| is unencoded.
return BN_mod_mul_montgomery(n, n, b->Ai, mont, ctx);
}
static int bn_blinding_create_param(BN_BLINDING *b, const BIGNUM *e,
const BN_MONT_CTX *mont, BN_CTX *ctx) {
int no_inverse;
if (!BN_rand_range_ex(b->A, 1, &mont->N) ||
// Compute |b->A|^-1 in Montgomery form. Note |BN_from_montgomery| +
// |BN_mod_inverse_blinded| is equivalent to, but more efficient than,
// |BN_mod_inverse_blinded| + |BN_to_montgomery|.
//
// We do not retry if |b->A| has no inverse. Finding a non-invertible
// value of |b->A| is equivalent to factoring |mont->N|. There is
// negligible probability of stumbling on one at random.
!BN_from_montgomery(b->Ai, b->A, mont, ctx) ||
!BN_mod_inverse_blinded(b->Ai, &no_inverse, b->Ai, mont, ctx) ||
// TODO(davidben): |BN_mod_exp_mont| internally computes the result in
// Montgomery form. Save a pair of Montgomery reductions and a
// multiplication by returning that value directly.
!BN_mod_exp_mont(b->A, b->A, e, &mont->N, ctx, mont) ||
!BN_to_montgomery(b->A, b->A, mont, ctx)) {
OPENSSL_PUT_ERROR(RSA, ERR_R_INTERNAL_ERROR);
return 0;
}
return 1;
}