[vlc-devel] [PATCH] add libfuzzer support

[Shaleen Jain]

On Wed, Jun 21, 2017 at 6:16 PM, Hugo Beauzée-Luyssen 
<hugo at beauzee.fr> wrote:
> Hi,
> 
> On Wed, Jun 21, 2017, at 02:36 PM, Shaleen Jain wrote:
>>  ---
>>   .gitignore            |  1 +
>>   configure.ac          |  8 ++++++++
>>   test/Makefile.am      |  2 ++
>>   test/fuzz/Makefile.am | 19 +++++++++++++++++++
>>   4 files changed, 30 insertions(+)
>>   create mode 100644 test/fuzz/Makefile.am
>> 
>>  diff --git a/.gitignore b/.gitignore
>>  index 0b0ee9cc20..fcd0e59213 100644
>>  --- a/.gitignore
>>  +++ b/.gitignore
>>  @@ -45,6 +45,7 @@ wxvlc
>>   vlc_install_dir/*
>>   plugins.dat
>>   patches/*
>>  +*_fuzzer
>> 
>>   include/vlc/libvlc_version.h
>> 
>>  diff --git a/configure.ac b/configure.ac
>>  index 67fc7deb1a..c289b69510 100644
>>  --- a/configure.ac
>>  +++ b/configure.ac
>>  @@ -94,6 +94,13 @@ AS_IF([test -n "${with_binary_version}"],[
>>            [Binary specific version])
>>   ])
>> 
>>  +AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [
>>  +#if !defined(__clang__)
>>  +#error
>>  +#endif])], have_clang=yes, have_clang=no)
>>  +
>>  +AM_CONDITIONAL(HAVE_CLANG, test "x$have_clang" = "xyes")
>>  +
> 
> As pointed out by Marvin, it would be more idiomatic to use
> ax_check_compile_flag (or something similar) to enable flags
> conditionally.

I don't think it would be worth adding a 75 line marco for a flag that 
is used
only maybe once, plus it not anymore idiomatic than ac_compile_ifelse
> 
> 
>>   dnl
>>   dnl  Check the operating system
>>   dnl
>>  @@ -4248,6 +4255,7 @@ AC_CONFIG_FILES([
>>     lib/Makefile
>>     bin/Makefile
>>     test/Makefile
>>  +  test/fuzz/Makefile
>>     modules/hw/mmal/Makefile
>>     share/vlc.appdata.xml.in
>>   ])
>>  diff --git a/test/Makefile.am b/test/Makefile.am
>>  index 95d4df6516..30c1bb56b6 100644
>>  --- a/test/Makefile.am
>>  +++ b/test/Makefile.am
>>  @@ -4,6 +4,8 @@
>> 
>>   AUTOMAKE_OPTIONS = subdir-objects
>> 
>>  +SUBDIRS = fuzz
>>  +
>>   extra_check_verbose = $(extra_check_verbose_$(V))
>>   extra_check_verbose_ = 
>> $(extra_check_flags__$(AM_DEFAULT_VERBOSITY))
>>   extra_check_verbose_0 = @echo TEST $@
>>  diff --git a/test/fuzz/Makefile.am b/test/fuzz/Makefile.am
>>  new file mode 100644
>>  index 0000000000..57eb04f13f
>>  --- /dev/null
>>  +++ b/test/fuzz/Makefile.am
>>  @@ -0,0 +1,19 @@
>>  +AUTOMAKE_OPTIONS = subdir-objects
>>  +
>>  +AM_CXXFLAGS = -fsanitize=address -fsanitize-address-use-after-scope
>>  -fsanitize=undefined -fno-sanitize-recover=undefined
>>  +if HAVE_CLANG
>>  +AM_CXXFLAGS += -fsanitize-coverage=trace-pc-guard,trace-cmp
>>  +else
>>  +AM_CXXFLAGS += -fsanitize-coverage=trace-pc
>>  +endif
>>  +
>>  +LIBVLCCORE = ../../src/libvlccore.la
>>  +LIBVLC = ../../lib/libvlc.la
>>  +
>>  +LDADD = $(LIBVLCCORE) $(LIBVLC) -L./ -lFuzzer
> 
> You need to check for libfuzzer presence in the configure. Also, I'm 
> not
> sure running fuzz testing for each 'make check' is a good idea.
> I'm not sure what would be the best way to do this, but I'd be in 
> favor
> of a separate target. Fuzz testing will most likely be quite long at
> some point, and we don't want to make all our source builds that run
> make check/make distcheck last for many hours.

make check will only build the fuzz binaries, not run them.
> 
> 
>>  +
>>  +check_PROGRAMS = \
>>  +       libvlc_demux_fuzzer
>>  +
>>  +libvlc_demux_fuzzer_SOURCES = libvlc_demux_fuzzer.cpp
> 
> I think you forgot to add the file :)

No, I planned to push a separate patch for that, which I did a few 
minutes ago.
> 
> 
>>  +
>>  --
>>  2.13.1
>> 
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> 
> 
> --
>   Hugo Beauzée-Luyssen
>   hugo at beauzee.fr
> _______________________________________________
> vlc-devel mailing list
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