/* ==================================================================== * 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 #include #include #include #include #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); } 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; }