[FFmpeg-devel] [PATCHv3] fate/integer.c: Connect test to fuzzer

[Michael Niedermayer]

On Fri, May 07, 2021 at 09:23:09PM +0530, Vedaa wrote:
> Hi,
> 
> I have added the inclusion guards and changed the author. 
> 
> ---
>  Makefile                  |  2 ++
>  libavutil/tests/integer.c | 21 ++----------------
>  libavutil/tests/integer.h | 45 +++++++++++++++++++++++++++++++++++++++
>  tools/Makefile            |  3 +++
>  tools/target_int_fuzzer.c | 35 ++++++++++++++++++++++++++++++
>  5 files changed, 87 insertions(+), 19 deletions(-)
>  create mode 100644 libavutil/tests/integer.h
>  create mode 100644 tools/target_int_fuzzer.c
> 
> diff --git a/Makefile b/Makefile
> index 7e9d8b08c3..92fe8cac65 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -62,6 +62,8 @@ 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) $(LIBFUZZER_PATH)
>  
> +tools/target_int_fuzzer$(EXESUF): tools/target_int_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/libavutil/tests/integer.c b/libavutil/tests/integer.c
> index d2c8f2a903..02e1d9219c 100644
> --- a/libavutil/tests/integer.c
> +++ b/libavutil/tests/integer.c
> @@ -18,31 +18,14 @@
>   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
>   */
>  
> -#include <stdint.h>
> -
> -#include "libavutil/avassert.h"
> -#include "libavutil/integer.h"
> -#include "libavutil/intmath.h"
> +#include "libavutil/tests/integer.h"
>  
>  int main(void){
>      int64_t a,b;
>  
>      for(a=7; a<256*256*256; a+=13215){
>          for(b=3; b<256*256*256; b+=27118){
> -            AVInteger ai= av_int2i(a);
> -            AVInteger bi= av_int2i(b);
> -
> -            av_assert0(av_i2int(ai) == a);
> -            av_assert0(av_i2int(bi) == b);
> -            av_assert0(av_i2int(av_add_i(ai,bi)) == a+b);
> -            av_assert0(av_i2int(av_sub_i(ai,bi)) == a-b);
> -            av_assert0(av_i2int(av_mul_i(ai,bi)) == a*b);
> -            av_assert0(av_i2int(av_shr_i(ai, 9)) == a>>9);
> -            av_assert0(av_i2int(av_shr_i(ai,-9)) == a<<9);
> -            av_assert0(av_i2int(av_shr_i(ai, 17)) == a>>17);
> -            av_assert0(av_i2int(av_shr_i(ai,-17)) == a<<17);
> -            av_assert0(av_log2_i(ai) == av_log2(a));
> -            av_assert0(av_i2int(av_div_i(ai,bi)) == a/b);
> +            TestInteger(a,b);
>          }
>      }
>      return 0;
> diff --git a/libavutil/tests/integer.h b/libavutil/tests/integer.h
> new file mode 100644
> index 0000000000..64a02b3869
> --- /dev/null
> +++ b/libavutil/tests/integer.h
> @@ -0,0 +1,45 @@
> +/*
> + * Copyright (c) 2004 Michael Niedermayer <michaelni at gmx.at>
> + *
> + * 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
> + */
> +#ifndef AVUTIL_TEST_INTEGER_H
> +#define AVUTIL_TEST_INTEGER_H
> +
> +#include <stdint.h>
> +#include "libavutil/avassert.h"
> +#include "libavutil/integer.h"
> +#include "libavutil/intmath.h"
> +
> +static inline void TestInteger(int64_t a, int64_t b)
> +{
> +        AVInteger ai= av_int2i(a);
> +        AVInteger bi= av_int2i(b);
> +
> +        av_assert0(av_i2int(ai) == a);
> +        av_assert0(av_i2int(bi) == b);
> +        av_assert0(av_i2int(av_add_i(ai,bi)) == a+b);
> +        av_assert0(av_i2int(av_sub_i(ai,bi)) == a-b);
> +        av_assert0(av_i2int(av_mul_i(ai,bi)) == a*b);
> +        av_assert0(av_i2int(av_shr_i(ai, 9)) == a>>9);
> +        av_assert0(av_i2int(av_shr_i(ai,-9)) == a<<9);
> +        av_assert0(av_i2int(av_shr_i(ai, 17)) == a>>17);
> +        av_assert0(av_i2int(av_shr_i(ai,-17)) == a<<17);
> +        av_assert0(av_log2_i(ai) == av_log2(a));
> +        av_assert0(av_i2int(av_div_i(ai,bi)) == a/b);

[...]
> +int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
> +    if (size < 2 * sizeof(int64_t))
> +        return 1;
> +
> +    int64_t a,b;
> +    a = AV_RB64(data);
> +    b = AV_RB64(data + sizeof(int64_t));
> +    TestInteger(a,b);
> +    return 0;

actually, i was a bit too quick with saying that i will apply this
i cannot apply this yet
with random 64bit input from the fuzzer
the operations will overflow on the 64bit side and mismatch and then
fail the asserts even if that wasnt undefined already.

thats not testing the AVInteger code correctly

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Awnsering whenever a program halts or runs forever is
On a turing machine, in general impossible (turings halting problem).
On any real computer, always possible as a real computer has a finite number
of states N, and will either halt in less than N cycles or never halt.
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