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a370582ba9
FFmpeg/tools/target_dec_fuzzer.c
Michael Niedermayer a370582ba9 tools/target_dec_fuzzer: Init parsepkt 
Fixes: memory corruption
Fixes: 16702/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PNG_fuzzer-5768418552184832

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2019-08-31 17:33:56 +02:00

285 lines
11 KiB
C
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/*
* This file is part of FFmpeg.
*
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* Targeted fuzzer that targets specific codecs depending on two
compile-time flags.
INSTRUCTIONS:
* Get the very fresh clang, e.g. see http://libfuzzer.info#versions
* Get and build libFuzzer:
svn co http://llvm.org/svn/llvm-project/llvm/trunk/lib/Fuzzer
./Fuzzer/build.sh
* build ffmpeg for fuzzing:
FLAGS="-fsanitize=address -fsanitize-coverage=trace-pc-guard,trace-cmp -g" CC="clang $FLAGS" CXX="clang++ $FLAGS" ./configure --disable-x86asm
make clean && make -j
* build the fuzz target.
Choose the value of FFMPEG_CODEC (e.g. AV_CODEC_ID_DVD_SUBTITLE) and
choose one of FUZZ_FFMPEG_VIDEO, FUZZ_FFMPEG_AUDIO, FUZZ_FFMPEG_SUBTITLE.
clang -fsanitize=address -fsanitize-coverage=trace-pc-guard,trace-cmp tools/target_dec_fuzzer.c -o target_dec_fuzzer -I. -DFFMPEG_CODEC=AV_CODEC_ID_MPEG1VIDEO -DFUZZ_FFMPEG_VIDEO ../../libfuzzer/libFuzzer.a -Llibavcodec -Llibavdevice -Llibavfilter -Llibavformat -Llibavresample -Llibavutil -Llibpostproc -Llibswscale -Llibswresample -Wl,--as-needed -Wl,-z,noexecstack -Wl,--warn-common -Wl,-rpath-link=:libpostproc:libswresample:libswscale:libavfilter:libavdevice:libavformat:libavcodec:libavutil:libavresample -lavdevice -lavfilter -lavformat -lavcodec -lswresample -lswscale -lavutil -ldl -lxcb -lxcb-shm -lxcb -lxcb-xfixes -lxcb -lxcb-shape -lxcb -lX11 -lasound -lm -lbz2 -lz -pthread
* create a corpus directory and put some samples there (empty dir is ok too):
mkdir CORPUS && cp some-files CORPUS
* Run fuzzing:
./target_dec_fuzzer -max_len=100000 CORPUS
More info:
http://libfuzzer.info
http://tutorial.libfuzzer.info
https://github.com/google/oss-fuzz
http://lcamtuf.coredump.cx/afl/
https://security.googleblog.com/2016/08/guided-in-process-fuzzing-of-chrome.html
*/
#include "config.h"
#include "libavutil/avassert.h"
#include "libavutil/imgutils.h"
#include "libavutil/intreadwrite.h"
#include "libavcodec/avcodec.h"
#include "libavcodec/bytestream.h"
#include "libavformat/avformat.h"
int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
extern AVCodec * codec_list[];
static void error(const char *err)
{
fprintf(stderr, "%s", err);
exit(1);
}
static AVCodec *c = NULL;
static AVCodec *AVCodecInitialize(enum AVCodecID codec_id)
{
AVCodec *res;
res = avcodec_find_decoder(codec_id);
if (!res)
error("Failed to find decoder");
return res;
}
static int subtitle_handler(AVCodecContext *avctx, void *frame,
int *got_sub_ptr, AVPacket *avpkt)
{
AVSubtitle sub;
int ret = avcodec_decode_subtitle2(avctx, &sub, got_sub_ptr, avpkt);
if (ret >= 0 && *got_sub_ptr)
avsubtitle_free(&sub);
return ret;
}
// Ensure we don't loop forever
const uint32_t maxiteration = 8096;
const uint64_t maxpixels_per_frame = 4096 * 4096;
uint64_t maxpixels;
static const uint64_t FUZZ_TAG = 0x4741542D5A5A5546ULL;
int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
const uint64_t fuzz_tag = FUZZ_TAG;
const uint8_t *last = data;
const uint8_t *end = data + size;
uint32_t it = 0;
uint64_t ec_pixels = 0;
int (*decode_handler)(AVCodecContext *avctx, AVFrame *picture,
int *got_picture_ptr,
const AVPacket *avpkt) = NULL;
AVCodecParserContext *parser = NULL;
if (!c) {
#ifdef FFMPEG_DECODER
#define DECODER_SYMBOL0(CODEC) ff_##CODEC##_decoder
#define DECODER_SYMBOL(CODEC) DECODER_SYMBOL0(CODEC)
extern AVCodec DECODER_SYMBOL(FFMPEG_DECODER);
codec_list[0] = &DECODER_SYMBOL(FFMPEG_DECODER);
avcodec_register(&DECODER_SYMBOL(FFMPEG_DECODER));
c = &DECODER_SYMBOL(FFMPEG_DECODER);
#else
avcodec_register_all();
c = AVCodecInitialize(FFMPEG_CODEC); // Done once.
#endif
av_log_set_level(AV_LOG_PANIC);
}
switch (c->type) {
case AVMEDIA_TYPE_AUDIO : decode_handler = avcodec_decode_audio4; break;
case AVMEDIA_TYPE_VIDEO : decode_handler = avcodec_decode_video2; break;
case AVMEDIA_TYPE_SUBTITLE: decode_handler = subtitle_handler ; break;
}
maxpixels = maxpixels_per_frame * maxiteration;
switch (c->id) {
// Allows a small input to generate gigantic output
case AV_CODEC_ID_DIRAC: maxpixels /= 8192; break;
case AV_CODEC_ID_MSRLE: maxpixels /= 16; break;
case AV_CODEC_ID_QTRLE: maxpixels /= 16; break;
case AV_CODEC_ID_SANM: maxpixels /= 16; break;
case AV_CODEC_ID_GIF: maxpixels /= 16; break;
// Performs slow frame rescaling in C
case AV_CODEC_ID_GDV: maxpixels /= 512; break;
// Postprocessing in C
case AV_CODEC_ID_HNM4_VIDEO:maxpixels /= 128; break;
// Cliping in C, generally slow even with small input
case AV_CODEC_ID_INDEO4: maxpixels /= 128; break;
}
AVCodecContext* ctx = avcodec_alloc_context3(c);
AVCodecContext* parser_avctx = avcodec_alloc_context3(NULL);
if (!ctx || !parser_avctx)
error("Failed memory allocation");
if (ctx->max_pixels == 0 || ctx->max_pixels > maxpixels_per_frame)
ctx->max_pixels = maxpixels_per_frame; //To reduce false positive OOM and hangs
ctx->refcounted_frames = 1; //To reduce false positive timeouts and focus testing on the refcounted API
if (size > 1024) {
GetByteContext gbc;
int extradata_size;
size -= 1024;
bytestream2_init(&gbc, data + size, 1024);
ctx->width = bytestream2_get_le32(&gbc);
ctx->height = bytestream2_get_le32(&gbc);
ctx->bit_rate = bytestream2_get_le64(&gbc);
ctx->bits_per_coded_sample = bytestream2_get_le32(&gbc);
// Try to initialize a parser for this codec, note, this may fail which just means we test without one
if (bytestream2_get_byte(&gbc) & 1)
parser = av_parser_init(c->id);
extradata_size = bytestream2_get_le32(&gbc);
if (extradata_size < size) {
ctx->extradata = av_mallocz(extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (ctx->extradata) {
ctx->extradata_size = extradata_size;
size -= ctx->extradata_size;
memcpy(ctx->extradata, data + size, ctx->extradata_size);
}
}
if (av_image_check_size(ctx->width, ctx->height, 0, ctx))
ctx->width = ctx->height = 0;
}
int res = avcodec_open2(ctx, c, NULL);
if (res < 0) {
avcodec_free_context(&ctx);
av_free(parser_avctx);
av_parser_close(parser);
return 0; // Failure of avcodec_open2() does not imply that a issue was found
}
parser_avctx->codec_id = ctx->codec_id;
int got_frame;
AVFrame *frame = av_frame_alloc();
if (!frame)
error("Failed memory allocation");
// Read very simple container
AVPacket avpkt, parsepkt;
av_init_packet(&avpkt);
av_init_packet(&parsepkt);
while (data < end && it < maxiteration) {
// Search for the TAG
while (data + sizeof(fuzz_tag) < end) {
if (data[0] == (fuzz_tag & 0xFF) && AV_RN64(data) == fuzz_tag)
break;
data++;
}
if (data + sizeof(fuzz_tag) > end)
data = end;
res = av_new_packet(&parsepkt, data - last);
if (res < 0)
error("Failed memory allocation");
memcpy(parsepkt.data, last, data - last);
data += sizeof(fuzz_tag);
last = data;
while (parsepkt.size > 0) {
if (parser) {
av_init_packet(&avpkt);
int ret = av_parser_parse2(parser, parser_avctx, &avpkt.data, &avpkt.size,
parsepkt.data, parsepkt.size,
parsepkt.pts, parsepkt.dts, parsepkt.pos);
if (avpkt.data == parsepkt.data) {
avpkt.buf = av_buffer_ref(parsepkt.buf);
if (!avpkt.buf)
error("Failed memory allocation");
} else {
if (av_packet_make_refcounted(&avpkt) < 0)
error("Failed memory allocation");
}
parsepkt.data += ret;
parsepkt.size -= ret;
parsepkt.pos += ret;
avpkt.pts = parser->pts;
avpkt.dts = parser->dts;
avpkt.pos = parser->pos;
if ( parser->key_frame == 1 ||
(parser->key_frame == -1 && parser->pict_type == AV_PICTURE_TYPE_I))
avpkt.flags |= AV_PKT_FLAG_KEY;
avpkt.flags |= parsepkt.flags & AV_PKT_FLAG_DISCARD;
} else {
av_packet_move_ref(&avpkt, &parsepkt);
}
// Iterate through all data
while (avpkt.size > 0 && it++ < maxiteration) {
av_frame_unref(frame);
int ret = decode_handler(ctx, frame, &got_frame, &avpkt);
ec_pixels += ctx->width * ctx->height;
if (it > 20 || ec_pixels > 4 * ctx->max_pixels)
ctx->error_concealment = 0;
if (ec_pixels > maxpixels)
goto maximums_reached;
if (ret <= 0 || ret > avpkt.size)
break;
if (ctx->codec_type != AVMEDIA_TYPE_AUDIO)
ret = avpkt.size;
avpkt.data += ret;
avpkt.size -= ret;
}
av_packet_unref(&avpkt);
}
av_packet_unref(&parsepkt);
}
maximums_reached:
av_packet_unref(&avpkt);
do {
got_frame = 0;
av_frame_unref(frame);
decode_handler(ctx, frame, &got_frame, &avpkt);
} while (got_frame == 1 && it++ < maxiteration);
fprintf(stderr, "pixels decoded: %"PRId64", iterations: %d\n", ec_pixels, it);
av_frame_free(&frame);
avcodec_free_context(&ctx);
avcodec_free_context(&parser_avctx);
av_parser_close(parser);
av_packet_unref(&parsepkt);
return 0;
}
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