openssl does not build with ubsan

[inferno-chromium]

https://oss-fuzz-build-logs.storage.googleapis.com/build_logs/openssl/latest.txt

@mikea, @kroeckx - any idea why ?

coverage=edge,indirect-calls,8bit-counters -fno-sanitize=alignment -o fuzz/bndiv-test fuzz/bndiv.o fuzz/test-corpus.o -L. -lcrypto -ldl /usr/local/lib/libc++.a
../../usr/lib/libFuzzingEngine.a(FuzzerIO.o): In function basic_ifstream': /usr/local/bin/../include/c++/v1/fstream:1067: undefined reference to __ubsan_vptr_type_cache'
/usr/local/bin/../include/c++/v1/fstream:1067: undefined reference to __ubsan_handle_dynamic_type_cache_miss_abort' ../../usr/lib/libFuzzingEngine.a(FuzzerIO.o): In function basic_istream':
/usr/local/bin/../include/c++/v1/istream:189: undefined reference to __ubsan_vptr_type_cache' /usr/local/bin/../include/c++/v1/istream:189: undefined reference to __ubsan_handle_dynamic_type_cache_miss_abort'
/usr/local/bin/../include/c++/v1/istream:189: undefined reference to __ubsan_vptr_type_cache' /usr/local/bin/../include/c++/v1/istream:189: undefined reference to __ubsan_handle_dynamic_type_cache_miss_abort'
../../usr/lib/libFuzzingEngine.a(FuzzerIO.o): In function std::__1::basic_ios<char, std::__1::char_traits<char> >::init(std::__1::basic_streambuf<char, std::__1::char_traits<char> >*)': /usr/local/bin/../include/c++/v1/ios:673: undefined reference to __ubsan_vptr_type_cache'
/usr/local/bin/../include/c++/v1/ios:673: undefined reference to __ubsan_handle_dynamic_type_cache_miss_abort' /usr/local/bin/../include/c++/v1/ios:674: undefined reference to __ubsan_vptr_type_cache'
/usr/local/bin/../include/c++/v1/ios:674: undefined reference to __ubsan_handle_dynamic_type_cache_miss_abort' /usr/local/bin/../include/c++/v1/ios:675: undefined reference to __ubsan_vptr_type_cache'
/usr/local/bin/../include/c++/v1/ios:675: undefined reference to __ubsan_handle_dynamic_type_cache_miss_abort' ../../usr/lib/libFuzzingEngine.a(FuzzerIO.o): In function basic_ifstream':
/usr/local/bin/../include/c++/v1/fstream:1069: undefined reference to __ubsan_vptr_type_cache' /usr/local/bin/../include/c++/v1/fstream:1069: undefined reference to __ubsan_handle_dynamic_type_cache_miss_abort'
/usr/local/bin/../include/c++/v1/fstream:1069: undefined reference to __ubsan_vptr_type_cache' /usr/local/bin/../include/c++/v1/fstream:1069: undefined reference to __ubsan_handle_dynamic_type_cache_miss_abort'

[kcc]

The linker command should have the same -fsanitize=* as the compiler command.
Does it?

[kroeckx]

I currently don't see what's wrong with the calling it, all arguments that should be there seem to be there.

[kroeckx]

So what I'm confused about is that it's all undefined references it's showing are for libFuzzingEngine.a, and I didn't expect that to get build with ubsan.

[mikea]

The root cause of this issue is openssl using clang (not clang++) to link the fuzzer. libFuzzingEngine.a is a C++ program and additional ubsan c++ runtime libraries have to be linked in. clang++ usually takes care of this. We were able to overcome the issue by specifying libc++ manually. (https://github.com/google/oss-fuzz/blob/master/projects/openssl/build.sh#L19) This list has to be expanded for undefined sanitizer.

I'll try to fix it on our side, but the proper fix would be to make openssl use clang++ for linking.

[kroeckx]

Thanks for fixing that.

I'd like to get rid of that hack. I remember having issues when we actually tried to use clang++, but I don't remember what exactly.

[mikea]

Can you create a variable to override the linker? Would be easy to try LD=clang++ make then.

[kroeckx]

LDCMD does that

[kroeckx]

I've been thinking about moving that libc++.a thing to the EX_LIBS, or maybe $FUZZER_LDFLAGS should get added to it? But I didn't try to set up a working test environment yet.

[kroeckx]

Maybe it's easier to use PLIB_LDFLAGS instead of EX_LIBS, that should be empty by default on Linux.

[mikea]

I want to remove FUZZER_LDFLAGS. They don't seem to be needed.

BTW #198 seems to work fine for both sanitizers.