libwebp/tests/fuzzer/huffman_fuzzer.c
Vincent Rabaud a35ea50de4 Add a fuzzer for ReadHuffmanCodes
Change-Id: If8c30aaa87c34007ae455a03daa7b3c0f22fc8c3
2023-09-12 23:41:29 +02:00

66 lines
2.4 KiB
C

// Copyright 2023 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////////
#include <stdint.h>
#include <string.h>
#include "src/dec/vp8li_dec.h"
#include "src/utils/bit_reader_utils.h"
#include "src/utils/huffman_utils.h"
#include "src/utils/utils.h"
#include "src/webp/format_constants.h"
int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
// Number of bits to initialize data.
static const int kColorCacheBitsBits = 4;
// 'num_htree_groups' is contained in the RG channel, hence 16 bits.
static const int kNumHtreeGroupsBits = 16;
if (size * sizeof(*data) < kColorCacheBitsBits + kNumHtreeGroupsBits) {
return 0;
}
// A non-NULL mapping brings minor changes that are tested by the normal
// fuzzer.
int* const mapping = NULL;
HuffmanTables huffman_tables;
memset(&huffman_tables, 0, sizeof(huffman_tables));
HTreeGroup* htree_groups = NULL;
VP8LDecoder* dec = VP8LNew();
if (dec == NULL) goto Error;
VP8LBitReader* const br = &dec->br_;
VP8LInitBitReader(br, data, size);
const int color_cache_bits = VP8LReadBits(br, kColorCacheBitsBits);
if (color_cache_bits < 1 || color_cache_bits > MAX_CACHE_BITS) goto Error;
const int num_htree_groups = VP8LReadBits(br, kNumHtreeGroupsBits);
// 'num_htree_groups' cannot be 0 as it is built from a non-empty image.
if (num_htree_groups == 0) goto Error;
// This variable is only useful when mapping is not NULL.
const int num_htree_groups_max = num_htree_groups;
ReadHuffmanCodesHelper(color_cache_bits, num_htree_groups,
num_htree_groups_max, mapping, dec, &huffman_tables,
&htree_groups);
Error:
WebPSafeFree(mapping);
VP8LHtreeGroupsFree(htree_groups);
VP8LHuffmanTablesDeallocate(&huffman_tables);
VP8LDelete(dec);
return 0;
}