Can't link libFuzzer.a using clang with libc++

I'm trying to link together:

libFuzzer.a, compiled with clang++-5.0 and -std=c++11
my fuzz driver, compiled with clang++-5.0 and -std=c++11 -stdlib=libc++
libcurl, compiled with clang-5.0

Specifically, this linker command is being executed:

/bin/bash ../../libtool --silent --tag=CXX --mode=link clang++-5.0 -I../../include -I../../lib -I../../lib -I../../tests/fuzz -fsanitize=address -fsanitize-address-use-after-scope -fsanitize-coverage=trace-pc-guard,trace-cmp -std=c++11 -stdlib=libc++ -o curl_fuzzer curl_fuzzer-curl_fuzzer.o ../../lib/libcurl.la /root/checkouts/Fuzzer/libFuzzer.a -lssh2 -lssl -lcrypto -lssl -lcrypto -lz -lpthread -lm

Executing this command outputs the following:

/bin/bash ../../libtool --silent --tag=CXX   --mode=link clang++-5.0 -I../../include -I../../lib -I../../lib -I../../tests/fuzz -fsanitize=address -fsanitize-address-use-after-scope -fsanitize-coverage=trace-pc-guard,trace-cmp -std=c++11 -stdlib=libc++   -o curl_fuzzer curl_fuzzer-curl_fuzzer.o ../../lib/libcurl.la /root/checkouts/Fuzzer/libFuzzer.a  -lssh2 -lssl -lcrypto -lssl -lcrypto -lz -lpthread -lm > /tmp/cat.txt 2>&1; head -20 /tmp/cat.txt
/root/checkouts/Fuzzer/libFuzzer.a(FuzzerIO.o): In function `fuzzer::FileToVector(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned long, bool)':
/root/checkouts/Fuzzer/./FuzzerIO.cpp:34: undefined reference to `std::basic_ifstream<char, std::char_traits<char> >::basic_ifstream(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::_Ios_Openmode)'
/root/checkouts/Fuzzer/./FuzzerIO.cpp:40: undefined reference to `std::istream::seekg(long, std::_Ios_Seekdir)'
/root/checkouts/Fuzzer/./FuzzerIO.cpp:41: undefined reference to `std::istream::tellg()'
/root/checkouts/Fuzzer/./FuzzerIO.cpp:47: undefined reference to `std::istream::seekg(long, std::_Ios_Seekdir)'
/root/checkouts/Fuzzer/./FuzzerIO.cpp:49: undefined reference to `std::istream::read(char*, long)'
/root/checkouts/Fuzzer/libFuzzer.a(FuzzerIO.o): In function `~basic_ifstream':
/usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/fstream:534: undefined reference to `VTT for std::basic_ifstream<char, std::char_traits<char> >'
/usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/fstream:534: undefined reference to `std::basic_ifstream<char, std::char_traits<char> >::~basic_ifstream()'
/root/checkouts/Fuzzer/libFuzzer.a(FuzzerIO.o): In function `~basic_ios':
/usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/bits/basic_ios.h:282: undefined reference to `std::ios_base::~ios_base()'
/root/checkouts/Fuzzer/libFuzzer.a(FuzzerIO.o): In function `~basic_ifstream':
/usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/fstream:534: undefined reference to `VTT for std::basic_ifstream<char, std::char_traits<char> >'
/usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/fstream:534: undefined reference to `std::basic_ifstream<char, std::char_traits<char> >::~basic_ifstream()'
/root/checkouts/Fuzzer/libFuzzer.a(FuzzerIO.o): In function `~basic_ios':
/usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/bits/basic_ios.h:282: undefined reference to `std::ios_base::~ios_base()'
/root/checkouts/Fuzzer/libFuzzer.a(FuzzerIO.o): In function `fuzzer::FileToString(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/root/checkouts/Fuzzer/./FuzzerIO.cpp:54: undefined reference to `std::basic_ifstream<char, std::char_traits<char> >::basic_ifstream(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::_Ios_Openmode)'
/root/checkouts/Fuzzer/libFuzzer.a(FuzzerIO.o): In function `~basic_ifstream':
/usr/bin/../lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/fstream:534: undefined reference to `VTT for std::basic_ifstream<char, std::char_traits<char> >'
<snip>

I've tried doing the following to fix this:

Adding -lc++ - doesn't do anything
Adding -lc++abi - doesn't do anything

It feels like I'm missing something obvious but I'm not sure what...

My installation of clang-5.0 comes from clang-5.0/kali-rolling.

回答1:

You have compiled part of your code with libstdc++ and part with libc++. When you link them together (using libc++), the parts that have references to libstdc++ don't get resolved.

For example, std::__cxx11::basic_string is definitely a libstdc++ symbol.

回答2:

Looks like for whatever reason kali's version of clang-5.0 doesn't link binaries with libc++ properly. I tested the same code with google's ossfuzz version of clang (clang-6.0) and everything linked together successfully.