X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_exp.c;h=f9353aaae0dc4eeb01947072210b438437b94706;hp=8c46e50bdcc9783d6bdd3ab056cae2547a62c92b;hb=e913d11f444e0b46ec1ebbf3340813693f4d869d;hpb=8c5a7b33c6269c3bd6bc0df6b4c22e4fba03b485 diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index 8c46e50bdc..f9353aaae0 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -1,115 +1,14 @@ -/* crypto/bn/bn_exp.c */ -/* 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.] - */ -/* ==================================================================== - * Copyright (c) 1998-2005 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 1995-2017 The OpenSSL Project Authors. All Rights Reserved. * + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html */ -#include "cryptlib.h" +#include "internal/cryptlib.h" +#include "internal/constant_time_locl.h" #include "bn_lcl.h" #include @@ -126,13 +25,7 @@ # include #endif -#undef RSAZ_ENABLED -#if defined(OPENSSL_BN_ASM_MONT) && \ - (defined(__x86_64) || defined(__x86_64__) || \ - defined(_M_AMD64) || defined(_M_X64)) -# include "rsaz_exp.h" -# define RSAZ_ENABLED -#endif +#include "rsaz_exp.h" #undef SPARC_T4_MONT #if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc)) @@ -150,17 +43,15 @@ int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) int i, bits, ret = 0; BIGNUM *v, *rr; - if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0) { + if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0 + || BN_get_flags(a, BN_FLG_CONSTTIME) != 0) { /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */ BNerr(BN_F_BN_EXP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); - return -1; + return 0; } BN_CTX_start(ctx); - if ((r == a) || (r == p)) - rr = BN_CTX_get(ctx); - else - rr = r; + rr = ((r == a) || (r == p)) ? BN_CTX_get(ctx) : r; v = BN_CTX_get(ctx); if (rr == NULL || v == NULL) goto err; @@ -185,13 +76,14 @@ int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) goto err; } } - if (r != rr) - BN_copy(r, rr); + if (r != rr && BN_copy(r, rr) == NULL) + goto err; + ret = 1; err: BN_CTX_end(ctx); bn_check_top(r); - return (ret); + return ret; } int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, @@ -204,7 +96,7 @@ int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, bn_check_top(m); /*- - * For even modulus m = 2^k*m_odd, it might make sense to compute + * For even modulus m = 2^k*m_odd, it might make sense to compute * a^p mod m_odd and a^p mod 2^k separately (with Montgomery * exponentiation for the odd part), using appropriate exponent * reductions, and combine the results using the CRT. @@ -239,17 +131,12 @@ int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, #define RECP_MUL_MOD #ifdef MONT_MUL_MOD - /* - * I have finally been able to take out this pre-condition of the top bit - * being set. It was caused by an error in BN_div with negatives. There - * was also another problem when for a^b%m a >= m. eay 07-May-97 - */ - /* if ((m->d[m->top-1]&BN_TBIT) && BN_is_odd(m)) */ - if (BN_is_odd(m)) { # ifdef MONT_EXP_WORD if (a->top == 1 && !a->neg - && (BN_get_flags(p, BN_FLG_CONSTTIME) == 0)) { + && (BN_get_flags(p, BN_FLG_CONSTTIME) == 0) + && (BN_get_flags(a, BN_FLG_CONSTTIME) == 0) + && (BN_get_flags(m, BN_FLG_CONSTTIME) == 0)) { BN_ULONG A = a->d[0]; ret = BN_mod_exp_mont_word(r, A, p, m, ctx, NULL); } else @@ -281,23 +168,30 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BIGNUM *val[TABLE_SIZE]; BN_RECP_CTX recp; - if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0) { + if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0 + || BN_get_flags(a, BN_FLG_CONSTTIME) != 0 + || BN_get_flags(m, BN_FLG_CONSTTIME) != 0) { /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */ BNerr(BN_F_BN_MOD_EXP_RECP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); - return -1; + return 0; } bits = BN_num_bits(p); - if (bits == 0) { - ret = BN_one(r); + /* x**0 mod 1 is still zero. */ + if (BN_is_one(m)) { + ret = 1; + BN_zero(r); + } else { + ret = BN_one(r); + } return ret; } BN_CTX_start(ctx); aa = BN_CTX_get(ctx); val[0] = BN_CTX_get(ctx); - if (!aa || !val[0]) + if (val[0] == NULL) goto err; BN_RECP_CTX_init(&recp); @@ -410,7 +304,9 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, BIGNUM *val[TABLE_SIZE]; BN_MONT_CTX *mont = NULL; - if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0) { + if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0 + || BN_get_flags(a, BN_FLG_CONSTTIME) != 0 + || BN_get_flags(m, BN_FLG_CONSTTIME) != 0) { return BN_mod_exp_mont_consttime(rr, a, p, m, ctx, in_mont); } @@ -424,7 +320,13 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, } bits = BN_num_bits(p); if (bits == 0) { - ret = BN_one(rr); + /* x**0 mod 1 is still zero. */ + if (BN_is_one(m)) { + ret = 1; + BN_zero(rr); + } else { + ret = BN_one(rr); + } return ret; } @@ -432,7 +334,7 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, d = BN_CTX_get(ctx); r = BN_CTX_get(ctx); val[0] = BN_CTX_get(ctx); - if (!d || !r || !val[0]) + if (val[0] == NULL) goto err; /* @@ -564,7 +466,7 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, goto err; ret = 1; err: - if ((in_mont == NULL) && (mont != NULL)) + if (in_mont == NULL) BN_MONT_CTX_free(mont); BN_CTX_end(ctx); bn_check_top(rr); @@ -601,15 +503,17 @@ static BN_ULONG bn_get_bits(const BIGNUM *a, int bitpos) static int MOD_EXP_CTIME_COPY_TO_PREBUF(const BIGNUM *b, int top, unsigned char *buf, int idx, - int width) + int window) { - size_t i, j; + int i, j; + int width = 1 << window; + BN_ULONG *table = (BN_ULONG *)buf; if (top > b->top) top = b->top; /* this works because 'buf' is explicitly * zeroed */ - for (i = 0, j = idx; i < top * sizeof b->d[0]; i++, j += width) { - buf[j] = ((unsigned char *)b->d)[i]; + for (i = 0, j = idx; i < top; i++, j += width) { + table[j] = b->d[i]; } return 1; @@ -617,15 +521,59 @@ static int MOD_EXP_CTIME_COPY_TO_PREBUF(const BIGNUM *b, int top, static int MOD_EXP_CTIME_COPY_FROM_PREBUF(BIGNUM *b, int top, unsigned char *buf, int idx, - int width) + int window) { - size_t i, j; + int i, j; + int width = 1 << window; + /* + * We declare table 'volatile' in order to discourage compiler + * from reordering loads from the table. Concern is that if + * reordered in specific manner loads might give away the + * information we are trying to conceal. Some would argue that + * compiler can reorder them anyway, but it can as well be + * argued that doing so would be violation of standard... + */ + volatile BN_ULONG *table = (volatile BN_ULONG *)buf; if (bn_wexpand(b, top) == NULL) return 0; - for (i = 0, j = idx; i < top * sizeof b->d[0]; i++, j += width) { - ((unsigned char *)b->d)[i] = buf[j]; + if (window <= 3) { + for (i = 0; i < top; i++, table += width) { + BN_ULONG acc = 0; + + for (j = 0; j < width; j++) { + acc |= table[j] & + ((BN_ULONG)0 - (constant_time_eq_int(j,idx)&1)); + } + + b->d[i] = acc; + } + } else { + int xstride = 1 << (window - 2); + BN_ULONG y0, y1, y2, y3; + + i = idx >> (window - 2); /* equivalent of idx / xstride */ + idx &= xstride - 1; /* equivalent of idx % xstride */ + + y0 = (BN_ULONG)0 - (constant_time_eq_int(i,0)&1); + y1 = (BN_ULONG)0 - (constant_time_eq_int(i,1)&1); + y2 = (BN_ULONG)0 - (constant_time_eq_int(i,2)&1); + y3 = (BN_ULONG)0 - (constant_time_eq_int(i,3)&1); + + for (i = 0; i < top; i++, table += width) { + BN_ULONG acc = 0; + + for (j = 0; j < xstride; j++) { + acc |= ( (table[j + 0 * xstride] & y0) | + (table[j + 1 * xstride] & y1) | + (table[j + 2 * xstride] & y2) | + (table[j + 3 * xstride] & y3) ) + & ((BN_ULONG)0 - (constant_time_eq_int(j,idx)&1)); + } + + b->d[i] = acc; + } } b->top = top; @@ -645,7 +593,7 @@ static int MOD_EXP_CTIME_COPY_FROM_PREBUF(BIGNUM *b, int top, * precomputation memory layout to limit data-dependency to a minimum to * protect secret exponents (cf. the hyper-threading timing attacks pointed * out by Colin Percival, - * http://www.daemong-consideredperthreading-considered-harmful/) + * http://www.daemonology.net/hyperthreading-considered-harmful/) */ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx, @@ -668,15 +616,22 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, bn_check_top(p); bn_check_top(m); - top = m->top; - - if (!(m->d[0] & 1)) { + if (!BN_is_odd(m)) { BNerr(BN_F_BN_MOD_EXP_MONT_CONSTTIME, BN_R_CALLED_WITH_EVEN_MODULUS); return (0); } + + top = m->top; + bits = BN_num_bits(p); if (bits == 0) { - ret = BN_one(rr); + /* x**0 mod 1 is still zero. */ + if (BN_is_one(m)) { + ret = 1; + BN_zero(rr); + } else { + ret = BN_one(rr); + } return ret; } @@ -737,8 +692,8 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, if (window >= 5) { window = 5; /* ~5% improvement for RSA2048 sign, and even * for RSA4096 */ - if ((top & 7) == 0) - powerbufLen += 2 * top * sizeof(m->d[0]); + /* reserve space for mont->N.d[] copy */ + powerbufLen += top * sizeof(mont->N.d[0]); } #endif (void)0; @@ -758,8 +713,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, else #endif if ((powerbufFree = - (unsigned char *)OPENSSL_malloc(powerbufLen + - MOD_EXP_CTIME_MIN_CACHE_LINE_WIDTH)) + OPENSSL_malloc(powerbufLen + MOD_EXP_CTIME_MIN_CACHE_LINE_WIDTH)) == NULL) goto err; @@ -959,7 +913,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, const BN_ULONG *not_used, const BN_ULONG *np, const BN_ULONG *n0, int num); - BN_ULONG *np = mont->N.d, *n0 = mont->n0, *np2; + BN_ULONG *n0 = mont->n0, *np; /* * BN_to_montgomery can contaminate words above .top [in @@ -970,11 +924,11 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, for (i = tmp.top; i < top; i++) tmp.d[i] = 0; - if (top & 7) - np2 = np; - else - for (np2 = am.d + top, i = 0; i < top; i++) - np2[2 * i] = np[i]; + /* + * copy mont->N.d[] to improve cache locality + */ + for (np = am.d + top, i = 0; i < top; i++) + np[i] = mont->N.d[i]; bn_scatter5(tmp.d, top, powerbuf, 0); bn_scatter5(am.d, am.top, powerbuf, 1); @@ -984,7 +938,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, # if 0 for (i = 3; i < 32; i++) { /* Calculate a^i = a^(i-1) * a */ - bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np2, n0, top, i - 1); + bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np, n0, top, i - 1); bn_scatter5(tmp.d, top, powerbuf, i); } # else @@ -995,7 +949,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, } for (i = 3; i < 8; i += 2) { int j; - bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np2, n0, top, i - 1); + bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np, n0, top, i - 1); bn_scatter5(tmp.d, top, powerbuf, i); for (j = 2 * i; j < 32; j *= 2) { bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); @@ -1003,13 +957,13 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, } } for (; i < 16; i += 2) { - bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np2, n0, top, i - 1); + bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np, n0, top, i - 1); bn_scatter5(tmp.d, top, powerbuf, i); bn_mul_mont(tmp.d, tmp.d, tmp.d, np, n0, top); bn_scatter5(tmp.d, top, powerbuf, 2 * i); } for (; i < 32; i += 2) { - bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np2, n0, top, i - 1); + bn_mul_mont_gather5(tmp.d, am.d, powerbuf, np, n0, top, i - 1); bn_scatter5(tmp.d, top, powerbuf, i); } # endif @@ -1038,11 +992,11 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, while (bits >= 0) { wvalue = bn_get_bits5(p->d, bits - 4); bits -= 5; - bn_power5(tmp.d, tmp.d, powerbuf, np2, n0, top, wvalue); + bn_power5(tmp.d, tmp.d, powerbuf, np, n0, top, wvalue); } } - ret = bn_from_montgomery(tmp.d, tmp.d, NULL, np2, n0, top); + ret = bn_from_montgomery(tmp.d, tmp.d, NULL, np, n0, top); tmp.top = top; bn_correct_top(&tmp); if (ret) { @@ -1053,9 +1007,9 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, } else #endif { - if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, 0, numPowers)) + if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, 0, window)) goto err; - if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&am, top, powerbuf, 1, numPowers)) + if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&am, top, powerbuf, 1, window)) goto err; /* @@ -1067,15 +1021,15 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, if (window > 1) { if (!BN_mod_mul_montgomery(&tmp, &am, &am, mont, ctx)) goto err; - if (!MOD_EXP_CTIME_COPY_TO_PREBUF - (&tmp, top, powerbuf, 2, numPowers)) + if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, 2, + window)) goto err; for (i = 3; i < numPowers; i++) { /* Calculate a^i = a^(i-1) * a */ if (!BN_mod_mul_montgomery(&tmp, &am, &tmp, mont, ctx)) goto err; - if (!MOD_EXP_CTIME_COPY_TO_PREBUF - (&tmp, top, powerbuf, i, numPowers)) + if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, i, + window)) goto err; } } @@ -1083,8 +1037,8 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, bits--; for (wvalue = 0, i = bits % window; i >= 0; i--, bits--) wvalue = (wvalue << 1) + BN_is_bit_set(p, bits); - if (!MOD_EXP_CTIME_COPY_FROM_PREBUF - (&tmp, top, powerbuf, wvalue, numPowers)) + if (!MOD_EXP_CTIME_COPY_FROM_PREBUF(&tmp, top, powerbuf, wvalue, + window)) goto err; /* @@ -1104,8 +1058,8 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, /* * Fetch the appropriate pre-computed value from the pre-buf */ - if (!MOD_EXP_CTIME_COPY_FROM_PREBUF - (&am, top, powerbuf, wvalue, numPowers)) + if (!MOD_EXP_CTIME_COPY_FROM_PREBUF(&am, top, powerbuf, wvalue, + window)) goto err; /* Multiply the result into the intermediate result */ @@ -1128,12 +1082,11 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, goto err; ret = 1; err: - if ((in_mont == NULL) && (mont != NULL)) + if (in_mont == NULL) BN_MONT_CTX_free(mont); if (powerbuf != NULL) { OPENSSL_cleanse(powerbuf, powerbufLen); - if (powerbufFree) - OPENSSL_free(powerbufFree); + OPENSSL_free(powerbufFree); } BN_CTX_end(ctx); return (ret); @@ -1146,7 +1099,7 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, int b, bits, ret = 0; int r_is_one; BN_ULONG w, next_w; - BIGNUM *d, *r, *t; + BIGNUM *r, *t; BIGNUM *swap_tmp; #define BN_MOD_MUL_WORD(r, w, m) \ (BN_mul_word(r, (w)) && \ @@ -1165,10 +1118,11 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, #define BN_TO_MONTGOMERY_WORD(r, w, mont) \ (BN_set_word(r, (w)) && BN_to_montgomery(r, r, (mont), ctx)) - if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0) { + if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0 + || BN_get_flags(m, BN_FLG_CONSTTIME) != 0) { /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */ BNerr(BN_F_BN_MOD_EXP_MONT_WORD, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); - return -1; + return 0; } bn_check_top(p); @@ -1187,8 +1141,9 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, if (BN_is_one(m)) { ret = 1; BN_zero(rr); - } else + } else { ret = BN_one(rr); + } return ret; } if (a == 0) { @@ -1198,10 +1153,9 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, } BN_CTX_start(ctx); - d = BN_CTX_get(ctx); r = BN_CTX_get(ctx); t = BN_CTX_get(ctx); - if (d == NULL || r == NULL || t == NULL) + if (t == NULL) goto err; if (in_mont != NULL) @@ -1278,7 +1232,7 @@ int BN_mod_exp_mont_word(BIGNUM *rr, BN_ULONG a, const BIGNUM *p, } ret = 1; err: - if ((in_mont == NULL) && (mont != NULL)) + if (in_mont == NULL) BN_MONT_CTX_free(mont); BN_CTX_end(ctx); bn_check_top(rr); @@ -1295,23 +1249,30 @@ int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, /* Table of variables obtained from 'ctx' */ BIGNUM *val[TABLE_SIZE]; - if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0) { + if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0 + || BN_get_flags(a, BN_FLG_CONSTTIME) != 0 + || BN_get_flags(m, BN_FLG_CONSTTIME) != 0) { /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */ BNerr(BN_F_BN_MOD_EXP_SIMPLE, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); - return -1; + return 0; } bits = BN_num_bits(p); - - if (bits == 0) { - ret = BN_one(r); + if (bits == 0) { + /* x**0 mod 1 is still zero. */ + if (BN_is_one(m)) { + ret = 1; + BN_zero(r); + } else { + ret = BN_one(r); + } return ret; } BN_CTX_start(ctx); d = BN_CTX_get(ctx); val[0] = BN_CTX_get(ctx); - if (!d || !val[0]) + if (val[0] == NULL) goto err; if (!BN_nnmod(val[0], a, m, ctx))