On Tue, Aug 20, 2024 at 03:03:47PM +0100, Daniel P. Berrangé wrote:
On Mon, Aug 19, 2024 at 09:39:38PM +0530, Rayhan Faizel wrote:This series introduces multiple fuzzers developed as part of Google Summer of Code 2024. We adopt a structure-aware fuzzing approach to fuzz libvirt XML formats. The fuzzing methodology makes use of libFuzzer and libprotobuf-mutator. The fuzzers work by mutating intermediate protobufs and converting them to XML. The fuzzing method in use requires inclusion of C++ sources. However, C++ compilation will be done only if '-Dfuzz' is enabled. Otherwise, libvirt will compile normally as before. The fuzzing method works only on clang compilers which support libFuzzer.Hmm, I wish you'd raised this issue on the list before investing all this work becasue IMHO the dependency on C++ is not something I would want to see in the libvirt project, even just for tests. It was a very delibrate decision that libvirt be a C project, not C++ project, and if we're going to extend libvirt to take code in any new language the choices that make sense looking to the future are Rust or Go, not C++.
That was unfortunate, but since Rayhan had the first implementation done in a very short time we rather spent the rest of the time enhancing the fuzzing and it definitely bore fruit -- some of the found things are fixed, some are still waiting for a patch or two. The crucial part of this is the existing libprotobuf-mutator which is already in C++ and does provide very specific C++ APIs. Another approach (except writing our own mutator) would be to keep the code in a separate repository. I'm not completely sure whether we would still need the code modifications, I don't remember our discussions about whether the fuzzing compilation could work with all current libvirt code compiled as C and only the fuzzing parts compiled in C++.
With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
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