308 lines
11 KiB
C
308 lines
11 KiB
C
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/*
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* Utilities for constant-time cryptography.
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*
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* Author: Emilia Kasper (emilia@openssl.org)
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* Based on previous work by Bodo Moeller, Emilia Kasper, Adam Langley
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* (Google).
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* ====================================================================
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* Copyright (c) 2014 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#include "internal.h"
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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static const unsigned int CONSTTIME_TRUE = (unsigned)(~0);
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static const unsigned int CONSTTIME_FALSE = 0;
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static const uint8_t CONSTTIME_TRUE_8 = 0xff;
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static const uint8_t CONSTTIME_FALSE_8 = 0;
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static int test_binary_op(unsigned int (*op)(unsigned int a, unsigned int b),
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const char* op_name, unsigned int a, unsigned int b,
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int is_true) {
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unsigned c = op(a, b);
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if (is_true && c != CONSTTIME_TRUE) {
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fprintf(stderr,
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"Test failed for %s(%du, %du): expected %du (TRUE), got %du\n",
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op_name, a, b, CONSTTIME_TRUE, c);
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return 1;
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} else if (!is_true && c != CONSTTIME_FALSE) {
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fprintf(stderr,
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"Test failed for %s(%du, %du): expected %du (FALSE), got %du\n",
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op_name, a, b, CONSTTIME_FALSE, c);
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return 1;
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}
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return 0;
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}
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static int test_binary_op_8(uint8_t (*op)(unsigned int a, unsigned int b),
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const char* op_name, unsigned int a, unsigned int b,
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int is_true) {
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uint8_t c = op(a, b);
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if (is_true && c != CONSTTIME_TRUE_8) {
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fprintf(stderr,
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"Test failed for %s(%du, %du): expected %u (TRUE), got %u\n",
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op_name, a, b, CONSTTIME_TRUE_8, c);
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return 1;
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} else if (!is_true && c != CONSTTIME_FALSE_8) {
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fprintf(stderr,
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"Test failed for %s(%du, %du): expected %u (FALSE), got %u\n",
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op_name, a, b, CONSTTIME_FALSE_8, c);
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return 1;
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}
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return 0;
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}
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static int test_is_zero(unsigned int a) {
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unsigned int c = constant_time_is_zero(a);
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if (a == 0 && c != CONSTTIME_TRUE) {
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fprintf(stderr,
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"Test failed for constant_time_is_zero(%du): expected %du (TRUE), "
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"got %du\n",
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a, CONSTTIME_TRUE, c);
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return 1;
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} else if (a != 0 && c != CONSTTIME_FALSE) {
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fprintf(stderr,
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"Test failed for constant_time_is_zero(%du): expected %du (FALSE), "
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"got %du\n",
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a, CONSTTIME_FALSE, c);
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return 1;
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}
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return 0;
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}
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static int test_is_zero_8(unsigned int a) {
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uint8_t c = constant_time_is_zero_8(a);
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if (a == 0 && c != CONSTTIME_TRUE_8) {
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fprintf(stderr,
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"Test failed for constant_time_is_zero(%du): expected %u (TRUE), "
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"got %u\n",
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a, CONSTTIME_TRUE_8, c);
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return 1;
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} else if (a != 0 && c != CONSTTIME_FALSE) {
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fprintf(stderr,
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"Test failed for constant_time_is_zero(%du): expected %u (FALSE), "
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"got %u\n",
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a, CONSTTIME_FALSE_8, c);
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return 1;
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}
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return 0;
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}
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static int test_select(unsigned int a, unsigned int b) {
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unsigned int selected = constant_time_select(CONSTTIME_TRUE, a, b);
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if (selected != a) {
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fprintf(stderr,
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"Test failed for constant_time_select(%du, %du,"
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"%du): expected %du(first value), got %du\n",
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CONSTTIME_TRUE, a, b, a, selected);
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return 1;
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}
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selected = constant_time_select(CONSTTIME_FALSE, a, b);
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if (selected != b) {
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fprintf(stderr,
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"Test failed for constant_time_select(%du, %du,"
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"%du): expected %du(second value), got %du\n",
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CONSTTIME_FALSE, a, b, b, selected);
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return 1;
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}
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return 0;
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}
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static int test_select_8(uint8_t a, uint8_t b) {
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uint8_t selected = constant_time_select_8(CONSTTIME_TRUE_8, a, b);
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if (selected != a) {
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fprintf(stderr,
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"Test failed for constant_time_select(%u, %u,"
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"%u): expected %u(first value), got %u\n",
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CONSTTIME_TRUE, a, b, a, selected);
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return 1;
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}
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selected = constant_time_select_8(CONSTTIME_FALSE_8, a, b);
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if (selected != b) {
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fprintf(stderr,
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"Test failed for constant_time_select(%u, %u,"
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"%u): expected %u(second value), got %u\n",
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CONSTTIME_FALSE, a, b, b, selected);
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return 1;
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}
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return 0;
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}
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static int test_select_int(int a, int b) {
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int selected = constant_time_select_int(CONSTTIME_TRUE, a, b);
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if (selected != a) {
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fprintf(stderr,
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"Test failed for constant_time_select(%du, %d,"
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"%d): expected %d(first value), got %d\n",
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CONSTTIME_TRUE, a, b, a, selected);
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return 1;
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}
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selected = constant_time_select_int(CONSTTIME_FALSE, a, b);
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if (selected != b) {
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fprintf(stderr,
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"Test failed for constant_time_select(%du, %d,"
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"%d): expected %d(second value), got %d\n",
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CONSTTIME_FALSE, a, b, b, selected);
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return 1;
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}
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return 0;
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}
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static int test_eq_int(int a, int b) {
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unsigned int equal = constant_time_eq_int(a, b);
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if (a == b && equal != CONSTTIME_TRUE) {
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fprintf(stderr,
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"Test failed for constant_time_eq_int(%d, %d): expected %du(TRUE), "
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"got %du\n",
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a, b, CONSTTIME_TRUE, equal);
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return 1;
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} else if (a != b && equal != CONSTTIME_FALSE) {
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fprintf(stderr,
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"Test failed for constant_time_eq_int(%d, %d): expected "
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"%du(FALSE), got %du\n",
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a, b, CONSTTIME_FALSE, equal);
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return 1;
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}
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return 0;
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}
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static int test_eq_int_8(int a, int b) {
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uint8_t equal = constant_time_eq_int_8(a, b);
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if (a == b && equal != CONSTTIME_TRUE_8) {
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fprintf(stderr,
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"Test failed for constant_time_eq_int_8(%d, %d): expected "
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"%u(TRUE), got %u\n",
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a, b, CONSTTIME_TRUE_8, equal);
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return 1;
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} else if (a != b && equal != CONSTTIME_FALSE_8) {
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fprintf(stderr,
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"Test failed for constant_time_eq_int_8(%d, %d): expected "
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"%u(FALSE), got %u\n",
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a, b, CONSTTIME_FALSE_8, equal);
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return 1;
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}
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return 0;
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}
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static unsigned int test_values[] = {0, 1, 1024, 12345, 32000, UINT_MAX / 2 - 1,
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UINT_MAX / 2, UINT_MAX / 2 + 1,
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UINT_MAX - 1, UINT_MAX};
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static uint8_t test_values_8[] = {0, 1, 2, 20, 32, 127, 128, 129, 255};
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static int signed_test_values[] = {
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0, 1, -1, 1024, -1024, 12345, -12345,
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32000, -32000, INT_MAX, INT_MIN, INT_MAX - 1, INT_MIN + 1};
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int main(int argc, char* argv[]) {
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unsigned int a, b, i, j;
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int c, d;
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uint8_t e, f;
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int num_failed = 0, num_all = 0;
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fprintf(stdout, "Testing constant time operations...\n");
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for (i = 0; i < sizeof(test_values) / sizeof(int); ++i) {
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a = test_values[i];
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num_failed += test_is_zero(a);
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num_failed += test_is_zero_8(a);
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num_all += 2;
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for (j = 0; j < sizeof(test_values) / sizeof(int); ++j) {
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b = test_values[j];
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num_failed +=
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test_binary_op(&constant_time_lt, "constant_time_lt", a, b, a < b);
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num_failed += test_binary_op_8(&constant_time_lt_8, "constant_time_lt_8",
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a, b, a < b);
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num_failed +=
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test_binary_op(&constant_time_lt, "constant_time_lt_8", b, a, b < a);
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num_failed += test_binary_op_8(&constant_time_lt_8, "constant_time_lt_8",
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b, a, b < a);
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num_failed +=
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test_binary_op(&constant_time_ge, "constant_time_ge", a, b, a >= b);
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num_failed += test_binary_op_8(&constant_time_ge_8, "constant_time_ge_8",
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a, b, a >= b);
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num_failed +=
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test_binary_op(&constant_time_ge, "constant_time_ge", b, a, b >= a);
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num_failed += test_binary_op_8(&constant_time_ge_8, "constant_time_ge_8",
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b, a, b >= a);
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num_failed +=
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test_binary_op(&constant_time_eq, "constant_time_eq", a, b, a == b);
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num_failed += test_binary_op_8(&constant_time_eq_8, "constant_time_eq_8",
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a, b, a == b);
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num_failed +=
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test_binary_op(&constant_time_eq, "constant_time_eq", b, a, b == a);
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num_failed += test_binary_op_8(&constant_time_eq_8, "constant_time_eq_8",
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b, a, b == a);
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num_failed += test_select(a, b);
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num_all += 13;
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}
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}
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for (i = 0; i < sizeof(signed_test_values) / sizeof(int); ++i) {
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c = signed_test_values[i];
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for (j = 0; j < sizeof(signed_test_values) / sizeof(int); ++j) {
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d = signed_test_values[j];
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num_failed += test_select_int(c, d);
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num_failed += test_eq_int(c, d);
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num_failed += test_eq_int_8(c, d);
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num_all += 3;
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}
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}
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for (i = 0; i < sizeof(test_values_8); ++i) {
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e = test_values_8[i];
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for (j = 0; j < sizeof(test_values_8); ++j) {
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f = test_values_8[j];
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num_failed += test_select_8(e, f);
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num_all += 1;
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}
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}
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if (!num_failed) {
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fprintf(stdout, "ok (ran %d tests)\n", num_all);
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fprintf(stdout, "PASS\n");
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return EXIT_SUCCESS;
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} else {
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fprintf(stdout, "%d of %d tests failed!\n", num_failed, num_all);
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return EXIT_FAILURE;
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}
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}
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