[FFmpeg-devel] [PATCH 2/2] configure: Use -fno-sanitize-recover

[Frank Plowman]

On 16/01/2025 19:12, Vitaly Buka via ffmpeg-devel wrote:
> UBSAN by default is just prints a mesage and
> moves on. This hides a few UBs in fate-suite.
> 
> Signed-off-by: Vitaly Buka <vitalybuka at google.com>
> ---
>  configure                     | 4 ++--
>  libavcodec/aacenc_pred.c      | 1 +
>  libavcodec/ffv1dec.c          | 1 +
>  libavcodec/ffv1enc_template.c | 1 +
>  libavcodec/get_bits.h         | 1 +
>  libavcodec/indeo3.c           | 2 +-
>  libavcodec/motion_est.c       | 1 +
>  libavcodec/mss2dsp.c          | 1 +
>  libavcodec/opus/dec.c         | 1 +
>  libavcodec/snow.h             | 1 +
>  libavcodec/svq1enc.c          | 1 +
>  libavfilter/vf_curves.c       | 1 +
>  libavfilter/vf_overlay.c      | 1 +
>  libavformat/mov.c             | 1 +
>  libswscale/input.c            | 6 ++++++
>  libswscale/output.c           | 4 ++++
>  libswscale/swscale_unscaled.c | 3 +++
>  17 files changed, 28 insertions(+), 3 deletions(-)
> 
> diff --git a/configure b/configure
> index 3a1e72e1c6..f2b4fd2c62 100755
> --- a/configure
> +++ b/configure
> @@ -4568,7 +4568,7 @@ set >> $logfile
>  test -n "$valgrind" && toolchain="valgrind-memcheck"
>  
>  enabled ossfuzz && ! echo $CFLAGS | grep -q -- "-fsanitize="  && ! echo $CFLAGS | grep -q -- "-fcoverage-mapping" &&{
> -    add_cflags  -fsanitize=address,undefined -fsanitize-coverage=trace-pc-guard,trace-cmp -fno-omit-frame-pointer
> +    add_cflags  -fsanitize=address,undefined -fsanitize-coverage=trace-pc-guard,trace-cmp -fno-omit-frame-pointer -fno-sanitize-recover=all
>      add_ldflags -fsanitize=address,undefined -fsanitize-coverage=trace-pc-guard,trace-cmp
>  }
>  
> @@ -4591,7 +4591,7 @@ add_sanitizer_flags(){
>              add_ldflags -fsanitize=thread
>          ;;
>          usan)
> -            add_cflags  -fsanitize=undefined
> +            add_cflags  -fsanitize=undefined -fno-sanitize-recover=all

I agree it would be good to return a nonzero exit code on detecting
undefined behaviour when running FATE, but this sets the flag for any
--toolchain=*-usan configuration.  Personally, I would find it a little
unexpected that compiling with --toolchain=*-usan results in anything
but the default behaviour of UBSAN, and one might wish to use UBSAN
without the flag when testing manually.  As an alternative, what about
instead setting UBSAN_OPTIONS=halt_on_error=1 only when running the FATE
suite or fuzzing?

-- 
Frank