zstd/tests/fuzz/zstd_frame_info.c
Nick Terrell 5717bd39ee [lib] Fix NULL pointer dereference
When the output buffer is `NULL` with size 0, but the frame content size
is non-zero, we will write to the NULL pointer because our bounds check
underflowed.

This was exposed by a recent PR that allowed an empty frame into the
single-pass shortcut in streaming mode.

* Fix the bug.
* Fix another NULL dereference in zstd-v1.
* Overflow checks in 32-bit mode.
* Add a dedicated test.
* Expose the bug in the dedicated simple_decompress fuzzer.
* Switch all mallocs in fuzzers to return NULL for size=0.
* Fix a new timeout in a fuzzer.

Neither clang nor gcc show a decompression speed regression on x86-64.
On x86-32 clang is slightly positive and gcc loses 2.5% of speed.

Credit to OSS-Fuzz.
2020-05-06 12:09:02 -07:00

44 lines
1.3 KiB
C

/*
* Copyright (c) 2016-2020, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
/**
* This fuzz target fuzzes all of the helper functions that consume compressed
* input.
*/
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include "fuzz_helpers.h"
#include "zstd_helpers.h"
int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
{
ZSTD_frameHeader zfh;
if (size == 0) {
src = NULL;
}
/* You can fuzz any helper functions here that are fast, and take zstd
* compressed data as input. E.g. don't expect the input to be a dictionary,
* so don't fuzz ZSTD_getDictID_fromDict().
*/
ZSTD_getFrameContentSize(src, size);
ZSTD_getDecompressedSize(src, size);
ZSTD_findFrameCompressedSize(src, size);
ZSTD_getDictID_fromFrame(src, size);
ZSTD_findDecompressedSize(src, size);
ZSTD_decompressBound(src, size);
ZSTD_frameHeaderSize(src, size);
ZSTD_isFrame(src, size);
ZSTD_getFrameHeader(&zfh, src, size);
ZSTD_getFrameHeader_advanced(&zfh, src, size, ZSTD_f_zstd1);
return 0;
}