d69d8f904c
We want to be in the same global state each time we come in FuzzerTestOneInput(). There are various reasons why we might not be that include: - Initialization that happens on first use. This is mostly the RUN_ONCE() things, or loading of error strings. - Results that get cached. For instance a stack that is sorted, RSA blinding that has been set up, ... So I try to trigger as much as possible in FuzzerInitialize(), and for things I didn't find out how to trigger this it needs to happen in FuzzerTestOneInput(). Reviewed-by: Rich Salz <rsalz@openssl.org> GH: #2023
124 lines
3.2 KiB
C
124 lines
3.2 KiB
C
/*
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* Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL licenses, (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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* https://www.openssl.org/source/license.html
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* or in the file LICENSE in the source distribution.
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*/
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/*
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* Confirm that if (d, r) = a / b, then b * d + r == a, and that sign(d) ==
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* sign(a), and 0 <= r <= b
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*/
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#include <stdio.h>
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#include <openssl/bn.h>
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#include <openssl/err.h>
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#include "fuzzer.h"
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static BN_CTX *ctx;
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static BIGNUM *b1;
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static BIGNUM *b2;
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static BIGNUM *b3;
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static BIGNUM *b4;
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static BIGNUM *b5;
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int FuzzerInitialize(int *argc, char ***argv)
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{
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b1 = BN_new();
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b2 = BN_new();
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b3 = BN_new();
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b4 = BN_new();
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b5 = BN_new();
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ctx = BN_CTX_new();
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OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL);
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ERR_get_state();
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return 1;
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}
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int FuzzerTestOneInput(const uint8_t *buf, size_t len)
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{
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int success = 0;
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size_t l1 = 0, l2 = 0;
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/* s1 and s2 will be the signs for b1 and b2. */
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int s1 = 0, s2 = 0;
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/* We are going to split the buffer in two, sizes l1 and l2, giving b1 and
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* b2.
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*/
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if (len > 0) {
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--len;
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/* Use first byte to divide the remaining buffer into 3Fths. I admit
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* this disallows some number sizes. If it matters, better ideas are
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* welcome (Ben).
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*/
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l1 = ((buf[0] & 0x3f) * len) / 0x3f;
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s1 = buf[0] & 0x40;
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s2 = buf[0] & 0x80;
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++buf;
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l2 = len - l1;
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}
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OPENSSL_assert(BN_bin2bn(buf, l1, b1) == b1);
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BN_set_negative(b1, s1);
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OPENSSL_assert(BN_bin2bn(buf + l1, l2, b2) == b2);
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BN_set_negative(b2, s2);
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/* divide by 0 is an error */
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if (BN_is_zero(b2)) {
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success = 1;
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goto done;
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}
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OPENSSL_assert(BN_div(b3, b4, b1, b2, ctx));
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if (BN_is_zero(b1))
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success = BN_is_zero(b3) && BN_is_zero(b4);
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else if (BN_is_negative(b1))
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success = (BN_is_negative(b3) != BN_is_negative(b2) || BN_is_zero(b3))
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&& (BN_is_negative(b4) || BN_is_zero(b4));
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else
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success = (BN_is_negative(b3) == BN_is_negative(b2) || BN_is_zero(b3))
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&& (!BN_is_negative(b4) || BN_is_zero(b4));
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OPENSSL_assert(BN_mul(b5, b3, b2, ctx));
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OPENSSL_assert(BN_add(b5, b5, b4));
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success = success && BN_cmp(b5, b1) == 0;
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if (!success) {
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BN_print_fp(stdout, b1);
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putchar('\n');
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BN_print_fp(stdout, b2);
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putchar('\n');
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BN_print_fp(stdout, b3);
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putchar('\n');
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BN_print_fp(stdout, b4);
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putchar('\n');
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BN_print_fp(stdout, b5);
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putchar('\n');
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printf("%d %d %d %d %d %d %d\n", BN_is_negative(b1),
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BN_is_negative(b2),
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BN_is_negative(b3), BN_is_negative(b4), BN_is_zero(b4),
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BN_is_negative(b3) != BN_is_negative(b2)
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&& (BN_is_negative(b4) || BN_is_zero(b4)),
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BN_cmp(b5, b1));
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puts("----\n");
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}
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done:
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OPENSSL_assert(success);
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ERR_clear_error();
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return 0;
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}
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void FuzzerCleanup(void)
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{
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BN_free(b1);
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BN_free(b2);
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BN_free(b3);
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BN_free(b4);
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BN_free(b5);
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BN_CTX_free(ctx);
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}
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