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/*
* Copyright (c) 2018 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/*
* Fuzzer for libvpx decoders
* ==========================
* Requirements
* --------------
* Requires Clang 6.0 or above as -fsanitize=fuzzer is used as a linker
* option.
* Steps to build
* --------------
* Clone libvpx repository
$git clone https://chromium.googlesource.com/webm/libvpx
* Create a directory in parallel to libvpx and change directory
$mkdir vpx_dec_fuzzer
$cd vpx_dec_fuzzer/
* Enable sanitizers (Supported: address integer memory thread undefined)
$source ../libvpx/tools/set_analyzer_env.sh address
* Configure libvpx.
* Note --size-limit and VPX_MAX_ALLOCABLE_MEMORY are defined to avoid
* Out of memory errors when running generated fuzzer binary
$../libvpx/configure --disable-unit-tests --size-limit=12288x12288 \
--extra-cflags="-DVPX_MAX_ALLOCABLE_MEMORY=1073741824" \
--disable-webm-io --enable-debug
* Build libvpx
$make -j32
* Build vp9 fuzzer
$ $CXX $CXXFLAGS -std=c++11 -DDECODER=vp9 \
-fsanitize=fuzzer -I../libvpx -I. -Wl,--start-group \
../libvpx/examples/vpx_dec_fuzzer.cc -o ./vpx_dec_fuzzer_vp9 \
./libvpx.a ./tools_common.c.o -Wl,--end-group
* DECODER should be defined as vp9 or vp8 to enable vp9/vp8
*
* create a corpus directory and copy some ivf files there.
* Based on which codec (vp8/vp9) is being tested, it is recommended to
* have corresponding ivf files in corpus directory
* Empty corpus directoy also is acceptable, though not recommended
$mkdir CORPUS && cp some-files CORPUS
* Run fuzzing:
$./vpx_dec_fuzzer_vp9 CORPUS
* References:
* http://llvm.org/docs/LibFuzzer.html
* https://github.com/google/oss-fuzz
*/
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <memory>
#include "./tools_common.h"
#include "vpx/vp8dx.h"
#include "vpx/vpx_decoder.h"
#include "vpx_ports/mem_ops.h"
#define VPX_TOSTRING(str) #str
#define VPX_STRINGIFY(str) VPX_TOSTRING(str)
static void CloseFile(FILE *file) { fclose(file); }
/* ReadFrame is derived from ivf_read_frame in ivfdec.c
* This function doesn't call warn(), but instead ignores those errors.
* This is done to minimize the prints on console when running fuzzer
* Also if fread fails to read frame_size number of bytes, instead of
* returning an error, this returns with partial frames.
* This is done to ensure that partial frames are sent to decoder.
*/
static int ReadFrame(FILE *infile, uint8_t **buffer, size_t *bytes_read,
size_t *buffer_size) {
char raw_header[IVF_FRAME_HDR_SZ] = { 0 };
size_t frame_size = 0;
if (fread(raw_header, IVF_FRAME_HDR_SZ, 1, infile) == 1) {
frame_size = mem_get_le32(raw_header);
if (frame_size > 256 * 1024 * 1024) {
frame_size = 0;
}
if (frame_size > *buffer_size) {
uint8_t *new_buffer = (uint8_t *)realloc(*buffer, 2 * frame_size);
if (new_buffer) {
*buffer = new_buffer;
*buffer_size = 2 * frame_size;
} else {
frame_size = 0;
}
}
}
if (!feof(infile)) {
*bytes_read = fread(*buffer, 1, frame_size, infile);
return 0;
}
return 1;
}
extern "C" void usage_exit(void) { exit(EXIT_FAILURE); }
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
std::unique_ptr<FILE, decltype(&CloseFile)> file(
fmemopen((void *)data, size, "rb"), &CloseFile);
if (file == nullptr) {
return 0;
}
// Ensure input contains at least one file header and one frame header
if (size < IVF_FILE_HDR_SZ + IVF_FRAME_HDR_SZ) {
return 0;
}
char header[IVF_FILE_HDR_SZ];
if (fread(header, 1, IVF_FILE_HDR_SZ, file.get()) != IVF_FILE_HDR_SZ) {
return 0;
}
const VpxInterface *decoder = get_vpx_decoder_by_name(VPX_STRINGIFY(DECODER));
if (decoder == nullptr) {
return 0;
}
vpx_codec_ctx_t codec;
// Set thread count in the range [1, 64].
const unsigned int threads = (data[IVF_FILE_HDR_SZ] & 0x3f) + 1;
vpx_codec_dec_cfg_t cfg = { threads, 0, 0 };
if (vpx_codec_dec_init(&codec, decoder->codec_interface(), &cfg, 0)) {
return 0;
}
uint8_t *buffer = nullptr;
size_t buffer_size = 0;
size_t frame_size = 0;
while (!ReadFrame(file.get(), &buffer, &frame_size, &buffer_size)) {
const vpx_codec_err_t err =
vpx_codec_decode(&codec, buffer, frame_size, nullptr, 0);
static_cast<void>(err);
vpx_codec_iter_t iter = nullptr;
vpx_image_t *img = nullptr;
while ((img = vpx_codec_get_frame(&codec, &iter)) != nullptr) {
}
}
vpx_codec_destroy(&codec);
free(buffer);
return 0;
}