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/*
* Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "internal/nelem.h"
#include <openssl/bio.h>
#include <openssl/bn.h>
#include <openssl/rand.h>
#include <openssl/err.h>
#include "testutil.h"
#define NUM_BITS (BN_BITS2 * 4)
#define BN_print_var(v) test_output_bignum(#v, v)
/*
* Test that r == 0 in test_exp_mod_zero(). Returns one on success,
* returns zero and prints debug output otherwise.
*/
static int a_is_zero_mod_one(const char *method, const BIGNUM *r,
const BIGNUM *a)
{
if (!BN_is_zero(r)) {
TEST_error("%s failed: a ** 0 mod 1 = r (should be 0)", method);
BN_print_var(a);
BN_print_var(r);
return 0;
}
return 1;
}
/*
* test_mod_exp_zero tests that x**0 mod 1 == 0. It returns zero on success.
*/
static int test_mod_exp_zero(void)
{
BIGNUM *a = NULL, *p = NULL, *m = NULL;
BIGNUM *r = NULL;
BN_ULONG one_word = 1;
BN_CTX *ctx = BN_CTX_new();
int ret = 1, failed = 0;
if (!TEST_ptr(m = BN_new())
|| !TEST_ptr(a = BN_new())
|| !TEST_ptr(p = BN_new())
|| !TEST_ptr(r = BN_new()))
goto err;
BN_one(m);
BN_one(a);
BN_zero(p);
if (!TEST_true(BN_rand(a, 1024, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY)))
goto err;
if (!TEST_true(BN_mod_exp(r, a, p, m, ctx)))
goto err;
if (!TEST_true(a_is_zero_mod_one("BN_mod_exp", r, a)))
failed = 1;
if (!TEST_true(BN_mod_exp_recp(r, a, p, m, ctx)))
goto err;
if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_recp", r, a)))
failed = 1;
if (!TEST_true(BN_mod_exp_simple(r, a, p, m, ctx)))
goto err;
if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_simple", r, a)))
failed = 1;
if (!TEST_true(BN_mod_exp_mont(r, a, p, m, ctx, NULL)))
goto err;
if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont", r, a)))
failed = 1;
if (!TEST_true(BN_mod_exp_mont_consttime(r, a, p, m, ctx, NULL)))
goto err;
if (!TEST_true(a_is_zero_mod_one("BN_mod_exp_mont_consttime", r, a)))
failed = 1;
/*
* A different codepath exists for single word multiplication
* in non-constant-time only.
*/
if (!TEST_true(BN_mod_exp_mont_word(r, one_word, p, m, ctx, NULL)))
goto err;
if (!TEST_BN_eq_zero(r)) {
TEST_error("BN_mod_exp_mont_word failed: "
"1 ** 0 mod 1 = r (should be 0)");
BN_print_var(r);
goto err;
}
ret = !failed;
err:
BN_free(r);
BN_free(a);
BN_free(p);
BN_free(m);
BN_CTX_free(ctx);
return ret;
}
static int test_mod_exp(int round)
{
BN_CTX *ctx;
unsigned char c;
int ret = 0;
BIGNUM *r_mont = NULL;
BIGNUM *r_mont_const = NULL;
BIGNUM *r_recp = NULL;
BIGNUM *r_simple = NULL;
BIGNUM *a = NULL;
BIGNUM *b = NULL;
BIGNUM *m = NULL;
if (!TEST_ptr(ctx = BN_CTX_new()))
goto err;
if (!TEST_ptr(r_mont = BN_new())
|| !TEST_ptr(r_mont_const = BN_new())
|| !TEST_ptr(r_recp = BN_new())
|| !TEST_ptr(r_simple = BN_new())
|| !TEST_ptr(a = BN_new())
|| !TEST_ptr(b = BN_new())
|| !TEST_ptr(m = BN_new()))
goto err;
RAND_bytes(&c, 1);
c = (c % BN_BITS) - BN_BITS2;
BN_rand(a, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
RAND_bytes(&c, 1);
c = (c % BN_BITS) - BN_BITS2;
BN_rand(b, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY);
RAND_bytes(&c, 1);
c = (c % BN_BITS) - BN_BITS2;
BN_rand(m, NUM_BITS + c, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD);
if (!TEST_true(BN_mod(a, a, m, ctx))
|| !TEST_true(BN_mod(b, b, m, ctx))
|| !TEST_true(BN_mod_exp_mont(r_mont, a, b, m, ctx, NULL))
|| !TEST_true(BN_mod_exp_recp(r_recp, a, b, m, ctx))
|| !TEST_true(BN_mod_exp_simple(r_simple, a, b, m, ctx))
|| !TEST_true(BN_mod_exp_mont_consttime(r_mont_const, a, b, m, ctx, NULL)))
goto err;
if (!TEST_BN_eq(r_simple, r_mont)
|| !TEST_BN_eq(r_simple, r_recp)
|| !TEST_BN_eq(r_simple, r_mont_const)) {
if (BN_cmp(r_simple, r_mont) != 0)
TEST_info("simple and mont results differ");
if (BN_cmp(r_simple, r_mont_const) != 0)
TEST_info("simple and mont const time results differ");
if (BN_cmp(r_simple, r_recp) != 0)
TEST_info("simple and recp results differ");
BN_print_var(a);
BN_print_var(b);
BN_print_var(m);
BN_print_var(r_simple);
BN_print_var(r_recp);
BN_print_var(r_mont);
BN_print_var(r_mont_const);
goto err;
}
ret = 1;
err:
BN_free(r_mont);
BN_free(r_mont_const);
BN_free(r_recp);
BN_free(r_simple);
BN_free(a);
BN_free(b);
BN_free(m);
BN_CTX_free(ctx);
return ret;
}
int setup_tests(void)
{
ADD_TEST(test_mod_exp_zero);
ADD_ALL_TESTS(test_mod_exp, 200);
return 1;
}
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