[FFmpeg-devel] [PATCH] Gsoc: add the two fuzzy targets

[Heng Zhang]

> 在 2021年4月19日，下午5:47，Michael Niedermayer <michael at niedermayer.cc> 写道：
> 
> On Mon, Apr 19, 2021 at 05:06:10PM +0800, a397341575 at 163.com <mailto:a397341575 at 163.com> wrote:
>> From: toseven <Byone.heng at gmail.com>
>> 
>> ---
>> Makefile                       |   5 ++
>> tools/Makefile                 |   6 ++
>> tools/target_avpacket_fuzzer.c | 125 +++++++++++++++++++++++++++++++++
>> tools/target_formats_fuzzer.c  | 120 +++++++++++++++++++++++++++++++
>> 4 files changed, 256 insertions(+)
>> create mode 100644 tools/target_avpacket_fuzzer.c
>> create mode 100644 tools/target_formats_fuzzer.c
>> 
>> diff --git a/Makefile b/Makefile
>> index 7e9d8b08c3..45509ab3b5 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -62,6 +62,11 @@ tools/target_dem_fuzzer$(EXESUF): tools/target_dem_fuzzer.o $(FF_DEP_LIBS)
>> tools/target_io_dem_fuzzer$(EXESUF): tools/target_io_dem_fuzzer.o $(FF_DEP_LIBS)
>> 	$(LD) $(LDFLAGS) $(LDEXEFLAGS) $(LD_O) $^ $(ELIBS) $(FF_EXTRALIBS) $(LIBFUZZER_PATH)
>> 
>> +tools/target_avpacket_fuzzer$(EXESUF): tools/target_avpacket_fuzzer.o $(FF_DEP_LIBS)
>> +	$(LD) $(LDFLAGS) $(LDEXEFLAGS) $(LD_O) $^ $(ELIBS) $(FF_EXTRALIBS) $(LIBFUZZER_PATH)
>> +
>> +tools/target_formats_fuzzer$(EXESUF): tools/target_formats_fuzzer.o $(FF_DEP_LIBS)
>> +	$(LD) $(LDFLAGS) $(LDEXEFLAGS) $(LD_O) $^ $(ELIBS) $(FF_EXTRALIBS) $(LIBFUZZER_PATH)
>> 
>> tools/enum_options$(EXESUF): ELIBS = $(FF_EXTRALIBS)
>> tools/enum_options$(EXESUF): $(FF_DEP_LIBS)
> 
>> diff --git a/tools/Makefile b/tools/Makefile
>> index 82baa8eadb..7ef720c8ba 100644
>> --- a/tools/Makefile
>> +++ b/tools/Makefile
>> @@ -17,6 +17,12 @@ tools/target_dem_fuzzer.o: tools/target_dem_fuzzer.c
>> tools/target_io_dem_fuzzer.o: tools/target_dem_fuzzer.c
>> 	$(COMPILE_C) -DIO_FLAT=0
>> 
>> +tools/target_avpacket_fuzzer.o: tools/target_avpacket_fuzzer.c
>> +	$(COMPILE_C) 
>> +
>> +tools/target_avpacket_fuzzer.o: tools/target_formats_fuzzer.c
>> +	$(COMPILE_C) 
>> +
> 
> The target is duplicate

This is my mistake.

> 
> 
> 
> 
>> OUTDIRS += tools
>> 
>> clean::
>> diff --git a/tools/target_avpacket_fuzzer.c b/tools/target_avpacket_fuzzer.c
>> new file mode 100644
>> index 0000000000..e5e7b3d4c8
>> --- /dev/null
>> +++ b/tools/target_avpacket_fuzzer.c
>> @@ -0,0 +1,125 @@
>> +/*
>> + * 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
>> + */
>> +
>> +#include <inttypes.h>
>> +#include <stdio.h>
>> +#include <stdlib.h>
>> +#include <string.h>
>> +
>> +#include "libavcodec/avcodec.h"
>> +#include "libavutil/error.h"
>> +
>> +int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
>> +
>> +static int setup_side_data_entry(AVPacket *avpkt)
>> +{
>> +    const uint8_t *data_name = NULL;
>> +    int ret = 0, bytes;
>> +    uint8_t *extra_data = NULL;
>> +
>> +    /* get side_data_name string */
>> +    data_name = av_packet_side_data_name(AV_PKT_DATA_NEW_EXTRADATA);
>> +    
>> +    /* Allocate a memory bloc */
>> +    bytes = strlen(data_name);
>> +
>> +    if (!(extra_data = av_malloc(bytes)))
>> +    {
>> +        ret = AVERROR(ENOMEM);
>> +        fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
>> +        exit(1);
>> +    }
>> +
>> +    /* copy side_data_name to extra_data array */
>> +    memcpy(extra_data, data_name, bytes);
>> +
>> +    /* create side data for AVPacket */
>> +    ret = av_packet_add_side_data(avpkt, AV_PKT_DATA_NEW_EXTRADATA, extra_data,
>> +                                  bytes);
>> +    
>> +    if (ret < 0)
>> +    {
>> +        fprintf(stderr, "Error occurred in av_packet_add_side_data: %s\n",
>> +        av_err2str(ret));
>> +    }
>> +    return ret;
> 
> the { } placing style mismatches whats used in FFmpeg (i dont mind but some people do mind)
> 
> more general, how much code coverage is gained with these 2 fuzzers compared to what already exists ?
> 
> thanks

Okay, I will modify my style to adopt for FFmpeg. What is more, I didn’t compare the code coverage between them. Do I have to do this?  I mainly refer to the fate test from libavcodec/tests/avpacket.c and libavfilter/tests/formats.c. 

> 
> [...]
> -- 
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> 
> "Nothing to hide" only works if the folks in power share the values of
> you and everyone you know entirely and always will -- Tom Scott
> 
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