1 /*
2 * Utilities for constant-time cryptography.
3 *
4 * Author: Emilia Kasper (emilia@openssl.org)
5 * Based on previous work by Bodo Moeller, Emilia Kasper, Adam Langley
6 * (Google).
7 * ====================================================================
8 * Copyright (c) 2014 The OpenSSL Project. All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * "This product includes cryptographic software written by
21 * Eric Young (eay@cryptsoft.com)"
22 * The word 'cryptographic' can be left out if the rouines from the library
23 * being used are not cryptographic related :-).
24 * 4. If you include any Windows specific code (or a derivative thereof) from
25 * the apps directory (application code) you must include an acknowledgement:
26 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
27 *
28 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 * The licence and distribution terms for any publically available version or
41 * derivative of this code cannot be changed. i.e. this code cannot simply be
42 * copied and put under another distribution licence
43 * [including the GNU Public Licence.]
44 */
45
46 #include "internal.h"
47
48 #include <limits.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51
52 #include <gtest/gtest.h>
53
54
55 static const unsigned CONSTTIME_TRUE = (unsigned)(~0);
56 static const unsigned CONSTTIME_FALSE = 0;
57 static const uint8_t CONSTTIME_TRUE_8 = 0xff;
58 static const uint8_t CONSTTIME_FALSE_8 = 0;
59
FromBool(bool b)60 static unsigned FromBool(bool b) {
61 return b ? CONSTTIME_TRUE : CONSTTIME_FALSE;
62 }
63
FromBool8(bool b)64 static uint8_t FromBool8(bool b) {
65 return b ? CONSTTIME_TRUE_8 : CONSTTIME_FALSE_8;
66 }
67
68 static unsigned test_values[] = {
69 0,
70 1,
71 1024,
72 12345,
73 32000,
74 UINT_MAX / 2 - 1,
75 UINT_MAX / 2,
76 UINT_MAX / 2 + 1,
77 UINT_MAX - 1,
78 UINT_MAX,
79 };
80
81 static uint8_t test_values_8[] = {0, 1, 2, 20, 32, 127, 128, 129, 255};
82
83 static int signed_test_values[] = {
84 0, 1, -1, 1024, -1024, 12345, -12345,
85 32000, -32000, INT_MAX, INT_MIN, INT_MAX - 1, INT_MIN + 1};
86
TEST(ConstantTimeTest,Test)87 TEST(ConstantTimeTest, Test) {
88 for (unsigned a : test_values) {
89 SCOPED_TRACE(a);
90
91 EXPECT_EQ(FromBool(a == 0), constant_time_is_zero(a));
92 EXPECT_EQ(FromBool8(a == 0), constant_time_is_zero_8(a));
93
94 for (unsigned b : test_values) {
95 SCOPED_TRACE(b);
96
97 EXPECT_EQ(FromBool(a < b), constant_time_lt(a, b));
98 EXPECT_EQ(FromBool8(a < b), constant_time_lt_8(a, b));
99
100 EXPECT_EQ(FromBool(a >= b), constant_time_ge(a, b));
101 EXPECT_EQ(FromBool8(a >= b), constant_time_ge_8(a, b));
102
103 EXPECT_EQ(FromBool(a == b), constant_time_eq(a, b));
104 EXPECT_EQ(FromBool8(a == b), constant_time_eq_8(a, b));
105
106 EXPECT_EQ(a, constant_time_select(CONSTTIME_TRUE, a, b));
107 EXPECT_EQ(b, constant_time_select(CONSTTIME_FALSE, a, b));
108 }
109 }
110
111 for (int a : signed_test_values) {
112 SCOPED_TRACE(a);
113 for (int b : signed_test_values) {
114 SCOPED_TRACE(b);
115
116 EXPECT_EQ(a, constant_time_select_int(CONSTTIME_TRUE, a, b));
117 EXPECT_EQ(b, constant_time_select_int(CONSTTIME_FALSE, a, b));
118
119 EXPECT_EQ(FromBool(a == b), constant_time_eq_int(a, b));
120 EXPECT_EQ(FromBool8(a == b), constant_time_eq_int_8(a, b));
121 }
122 }
123
124 for (uint8_t a : test_values_8) {
125 SCOPED_TRACE(static_cast<int>(a));
126 for (uint8_t b : test_values_8) {
127 SCOPED_TRACE(static_cast<int>(b));
128 EXPECT_EQ(a, constant_time_select_8(CONSTTIME_TRUE_8, a, b));
129 EXPECT_EQ(b, constant_time_select_8(CONSTTIME_FALSE_8, a, b));
130 }
131 }
132 }
133