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/*
* Utilities for constant-time cryptography.
*
* Author: Emilia Kasper (emilia@openssl.org)
* Based on previous work by Bodo Moeller, Emilia Kasper, Adam Langley
* (Google).
* ====================================================================
* Copyright (c) 2014 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 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 "internal.h"
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits>
#include <gtest/gtest.h>
#include "test/test_util.h"
#include <openssl/mem.h>
#include <openssl/rand.h>
static uint8_t FromBool8(bool b) {
return b ? CONSTTIME_TRUE_8 : CONSTTIME_FALSE_8;
}
static crypto_word_t FromBoolW(bool b) {
return b ? CONSTTIME_TRUE_W : CONSTTIME_FALSE_W;
}
static const uint8_t test_values_8[] = {0, 1, 2, 20, 32, 127, 128, 129, 255};
static crypto_word_t test_values_w[] = {
0,
1,
1024,
12345,
32000,
#if defined(OPENSSL_64_BIT)
0xffffffff / 2 - 1,
0xffffffff / 2,
0xffffffff / 2 + 1,
0xffffffff - 1,
0xffffffff,
#endif
std::numeric_limits<crypto_word_t>::max() / 2 - 1,
std::numeric_limits<crypto_word_t>::max() / 2,
std::numeric_limits<crypto_word_t>::max() / 2 + 1,
std::numeric_limits<crypto_word_t>::max() - 1,
std::numeric_limits<crypto_word_t>::max(),
};
static int signed_test_values[] = {
0, 1, -1, 1024, -1024, 12345, -12345,
32000, -32000, INT_MAX, INT_MIN, INT_MAX - 1, INT_MIN + 1};
TEST(ConstantTimeTest, Test) {
for (crypto_word_t a : test_values_w) {
SCOPED_TRACE(a);
EXPECT_EQ(FromBoolW(a == 0), constant_time_is_zero_w(a));
EXPECT_EQ(FromBool8(a == 0), constant_time_is_zero_8(a));
for (crypto_word_t b : test_values_w) {
SCOPED_TRACE(b);
EXPECT_EQ(FromBoolW(a < b), constant_time_lt_w(a, b));
EXPECT_EQ(FromBool8(a < b), constant_time_lt_8(a, b));
EXPECT_EQ(FromBoolW(a >= b), constant_time_ge_w(a, b));
EXPECT_EQ(FromBool8(a >= b), constant_time_ge_8(a, b));
EXPECT_EQ(FromBoolW(a == b), constant_time_eq_w(a, b));
EXPECT_EQ(FromBool8(a == b), constant_time_eq_8(a, b));
EXPECT_EQ(a, constant_time_select_w(CONSTTIME_TRUE_W, a, b));
EXPECT_EQ(b, constant_time_select_w(CONSTTIME_FALSE_W, a, b));
}
}
for (int a : signed_test_values) {
SCOPED_TRACE(a);
for (int b : signed_test_values) {
SCOPED_TRACE(b);
EXPECT_EQ(a, constant_time_select_int(CONSTTIME_TRUE_W, a, b));
EXPECT_EQ(b, constant_time_select_int(CONSTTIME_FALSE_W, a, b));
EXPECT_EQ(FromBoolW(a == b), constant_time_eq_int(a, b));
EXPECT_EQ(FromBool8(a == b), constant_time_eq_int_8(a, b));
}
}
for (uint8_t a : test_values_8) {
SCOPED_TRACE(static_cast<int>(a));
for (uint8_t b : test_values_8) {
SCOPED_TRACE(static_cast<int>(b));
EXPECT_EQ(a, constant_time_select_8(CONSTTIME_TRUE_8, a, b));
EXPECT_EQ(b, constant_time_select_8(CONSTTIME_FALSE_8, a, b));
}
}
}
TEST(ConstantTimeTest, MemCmp) {
uint8_t buf[256], copy[256];
RAND_bytes(buf, sizeof(buf));
OPENSSL_memcpy(copy, buf, sizeof(buf));
EXPECT_EQ(0, CRYPTO_memcmp(buf, copy, sizeof(buf)));
for (size_t i = 0; i < sizeof(buf); i++) {
for (uint8_t bit = 1; bit != 0; bit <<= 1) {
OPENSSL_memcpy(copy, buf, sizeof(buf));
copy[i] ^= bit;
EXPECT_NE(0, CRYPTO_memcmp(buf, copy, sizeof(buf)));
}
}
}
TEST(ConstantTimeTest, ValueBarrier) {
for (int i = 0; i < 10; i++) {
crypto_word_t word;
RAND_bytes(reinterpret_cast<uint8_t *>(&word), sizeof(word));
EXPECT_EQ(word, value_barrier_w(word));
uint32_t u32;
RAND_bytes(reinterpret_cast<uint8_t *>(&u32), sizeof(u32));
EXPECT_EQ(u32, value_barrier_u32(u32));
uint64_t u64;
RAND_bytes(reinterpret_cast<uint8_t *>(&u64), sizeof(u64));
EXPECT_EQ(u64, value_barrier_u64(u64));
}
}
TEST(ConstantTimeTest, MemCmov) {
for (int i = 0; i < 100; i++) {
uint8_t out[256], in[256];
RAND_bytes(out, sizeof(out));
RAND_bytes(in, sizeof(in));
uint8_t b = 0;
RAND_bytes(&b, 1);
b = constant_time_is_zero_8(b & 0xf);
uint8_t ref_in[256];
OPENSSL_memcpy(ref_in, in, sizeof(in));
uint8_t ref_out[256];
OPENSSL_memcpy(ref_out, out, sizeof(out));
if (b) {
OPENSSL_memcpy(ref_out, in, sizeof(in));
}
CONSTTIME_SECRET(out, sizeof(out));
CONSTTIME_SECRET(in, sizeof(in));
CONSTTIME_SECRET(&b, 1);
constant_time_conditional_memcpy(out, in, sizeof(out), b);
CONSTTIME_DECLASSIFY(&in, sizeof(in));
CONSTTIME_DECLASSIFY(&out, sizeof(out));
EXPECT_EQ(Bytes(in), Bytes(ref_in));
EXPECT_EQ(Bytes(out), Bytes(ref_out));
}
}
TEST(ConstantTimeTest, MemCxor) {
for (int i = 0; i < 100; i++) {
uint8_t out[256], in[256];
RAND_bytes(out, sizeof(out));
RAND_bytes(in, sizeof(in));
uint8_t b = 0;
RAND_bytes(&b, 1);
b = constant_time_is_zero_8(b & 0xf);
uint8_t ref_in[256];
OPENSSL_memcpy(ref_in, in, sizeof(in));
uint8_t ref_out[256];
OPENSSL_memcpy(ref_out, out, sizeof(out));
if (b) {
for (size_t j = 0; j < sizeof(ref_out); ++j) {
ref_out[j] ^= in[j];
}
}
CONSTTIME_SECRET(out, sizeof(out));
CONSTTIME_SECRET(in, sizeof(in));
CONSTTIME_SECRET(&b, 1);
constant_time_conditional_memxor(out, in, sizeof(out), b);
CONSTTIME_DECLASSIFY(&in, sizeof(in));
CONSTTIME_DECLASSIFY(&out, sizeof(out));
EXPECT_EQ(Bytes(in), Bytes(ref_in));
EXPECT_EQ(Bytes(out), Bytes(ref_out));
}
}