-/* 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 "internal/cryptlib.h"
+#include "internal/constant_time_locl.h"
#include "bn_lcl.h"
#include <stdlib.h>
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;
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,
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.
#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
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);
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);
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);
}
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;
/*
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;
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;
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;
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
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);
# 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
}
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);
}
}
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
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) {
} 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;
/*
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;
}
}
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;
/*
/*
* 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 */
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)) && \
#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);
}
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)
/* 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);
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))
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