fuzz/libtasn1_parser2tree_fuzzer.c

/*
 * Copyright(c) 2019 Free Software Foundation, Inc.
 *
 * This file is part of libtasn1.
 *
 * Libtasn1 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Libtasn1 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libtasn1.  If not, see <https://www.gnu.org/licenses/>.
 *
 * This fuzzer is testing asn1_parser2tree()'s robustness with arbitrary ASN.1
 * input data.
 */

#include <config.h>

#include <stdlib.h> // malloc, free
#include <string.h> // strcmp, memcpy

#include "libtasn1.h"
#include "fuzzer.h"

static const uint8_t *g_data;
static size_t g_size;

#if defined HAVE_DLFCN_H && defined HAVE_FMEMOPEN
#include <dlfcn.h>
#ifdef RTLD_NEXT /* Not defined e.g. on CygWin */

FILE *fopen(const char *pathname, const char *mode) {
  FILE * (*libc_fopen)(const char *, const char *) =
    (FILE * (*)(const char *, const char *)) dlsym(RTLD_NEXT, "fopen");

  if (!strcmp(pathname, "pkix.asn"))
    return fmemopen((void *) g_data, g_size, mode);

  return libc_fopen(pathname, mode);
}
#endif
#endif

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
{
	char errorDescription[ASN1_MAX_ERROR_DESCRIPTION_SIZE];
	asn1_node definitions = NULL;

	if (size > 10000) // same as max_len = 10000 in .options file
		return 0;

	g_data = data;
	g_size = size;

	int rc = asn1_parser2tree("pkix.asn", &definitions, errorDescription);
	if (rc == ASN1_SUCCESS) {
		asn1_delete_structure(&definitions);
	}

	return 0;
}