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| /*
| * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
| *
| * Licensed under the OpenSSL licenses, (the "License");
| * you may not use this file except in compliance with the License.
| * You may obtain a copy of the License at
| * https://www.openssl.org/source/license.html
| * or in the file LICENSE in the source distribution.
| */
|
| /*
| * Confirm that a^b mod c agrees when calculated cleverly vs naively, for
| * random a, b and c.
| */
|
| #include <stdio.h>
| #include <openssl/bn.h>
| #include <openssl/err.h>
| #include "fuzzer.h"
|
|
| int FuzzerInitialize(int *argc, char ***argv)
| {
| OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
| ERR_get_state();
|
| return 1;
| }
|
| int FuzzerTestOneInput(const uint8_t *buf, size_t len)
| {
| int success = 0;
| size_t l1 = 0, l2 = 0, l3 = 0;
| int s1 = 0, s3 = 0;
| BN_CTX *ctx;
| BIGNUM *b1;
| BIGNUM *b2;
| BIGNUM *b3;
| BIGNUM *b4;
| BIGNUM *b5;
|
| b1 = BN_new();
| b2 = BN_new();
| b3 = BN_new();
| b4 = BN_new();
| b5 = BN_new();
| ctx = BN_CTX_new();
|
| /* Divide the input into three parts, using the values of the first two
| * bytes to choose lengths, which generate b1, b2 and b3. Use three bits
| * of the third byte to choose signs for the three numbers.
| */
| if (len > 2) {
| len -= 3;
| l1 = (buf[0] * len) / 255;
| ++buf;
| l2 = (buf[0] * (len - l1)) / 255;
| ++buf;
| l3 = len - l1 - l2;
|
| s1 = buf[0] & 1;
| s3 = buf[0] & 4;
| ++buf;
| }
| OPENSSL_assert(BN_bin2bn(buf, l1, b1) == b1);
| BN_set_negative(b1, s1);
| OPENSSL_assert(BN_bin2bn(buf + l1, l2, b2) == b2);
| OPENSSL_assert(BN_bin2bn(buf + l1 + l2, l3, b3) == b3);
| BN_set_negative(b3, s3);
|
| /* mod 0 is undefined */
| if (BN_is_zero(b3)) {
| success = 1;
| goto done;
| }
|
| OPENSSL_assert(BN_mod_exp(b4, b1, b2, b3, ctx));
| OPENSSL_assert(BN_mod_exp_simple(b5, b1, b2, b3, ctx));
|
| success = BN_cmp(b4, b5) == 0;
| if (!success) {
| BN_print_fp(stdout, b1);
| putchar('\n');
| BN_print_fp(stdout, b2);
| putchar('\n');
| BN_print_fp(stdout, b3);
| putchar('\n');
| BN_print_fp(stdout, b4);
| putchar('\n');
| BN_print_fp(stdout, b5);
| putchar('\n');
| }
|
| done:
| OPENSSL_assert(success);
| BN_free(b1);
| BN_free(b2);
| BN_free(b3);
| BN_free(b4);
| BN_free(b5);
| BN_CTX_free(ctx);
| ERR_clear_error();
|
| return 0;
| }
|
| void FuzzerCleanup(void)
| {
| }
|
|
