cbmc VS infer

This appears to be more limited than what CBMC[1] (the C Bounded Model Checker) can do. CBMC can do function contracts. CBMC can prove memory safety and even the absence of memory leaks for non-trivial code bases that pass pointers all over the place that must eventually be freed. Applying all the annotations to make this happen though is like 10x the work of getting the program actually running in the first place. CBMC definitely makes C safer than even safe Rust for projects that can invest the time to use it. There is an experimental Rust front end to CBMC called Kani[2] that aims to verify unsafe Rust (thus making unsafe Rust become safe) but it is far from the speed and robustness of the C front end.

[1] https://github.com/diffblue/cbmc

[2] https://github.com/model-checking/kani

https://github.com/diffblue/cbmc/issues/7732 I'll note that some form of undefined behavior checking / documentation is on the roadmap for the next major version

So it seems to use cmbc and a bunch of other tools from cprover under the hood (bundled in the github release and setup on first run...). I would really like to have this "how" more visible in the documentation, it's essential to hint at the limitations of such an automated prover, even if the underlying system is rather powerful.

> The only reliable way to have bug-free code is to prove it. It requires solid mathematical foundations and a programming language that allows formal proofs.

I'm going to be the "actually" guy and say that, actually, you can formally verify some studff about programs written in traditional/mainstream languages, like C. Matter of fact, this is a pretty lively research area, with some tools like CBMC [0] and Infer [1] also getting significant adoption in the industry.

[0]: https://github.com/diffblue/cbmc

[1]: https://fbinfer.com/

I think most development occurs on problems that can't be formally modeled anyway. Most developers work on things like, "can you add this feature to the e-commerce site? And can the pop-up be blue?" which isn't really model-able.

But that's not to say that formal methods are useless! We can still prove some interesting aspects of programs -- for example, that every lock that gets acquired later gets released. I think tools like Infer[0] could become common in the coming years.

[0]: https://fbinfer.com/

Using infer, someone else exploited null-dereference checks to introduce simple affine types in C++. Cppcheck also checks for null-dereferences. Unfortunately, that approach means that borrow-counting references have a larger sizeof than non-borrow counting references, so optimizing the count away potentially changes the semantics of a program which introduces a whole new way of writing subtly wrong code.

Meta/Facebook are long time OCaml users, their logo is on the OCaml website. Their static analysis tool and its predecessor are both written in OCaml.

Then this idea that the US government will tell tech companies how to write secure software. Let's get this straight, the private sector, especially big tech is miles ahead of US government in this regard. Microsoft literally invented threat modelling and modern exploit mitigations. Facebook has the best appsec processes pretty much in the whole world, including their own cutting edge code analyzer. AWS uses formal verification everywhere. Meanwhile the US government itself runs mission-critical systems that's almost literally held together by bubble gum and toothpicks. Maybe they could dial down the arrogance a tad, get their own shit together, learn how this cyber stuff is actually done and only then try lecturing everyone else.

Efforts: Dependabot, CodeQL, Coverity, facebook's Infer tool, etc

I notice there isn't fbinfer. It's pretty cool, and is used for this library.

"Move fast, break stuff" is a great approach when you aren't pushing the broken bits to production. Fuck, even Facebook, the big "move fast, break stuff" company, uses tools to detect errors in its continuous integration toolchain. https://fbinfer.com/

TBH, there's a non-zero amount of non-"ivory tower" tools you may have used that are written in functional languages. Say, Pandoc or Shellcheck are written in Haskell; Infer and Flow are written in OCaml. RabbitMQ and Whatsapp are implemented in Erlang (FB Messenger was too, originally; they switched to the C++ servers later). Twitter backend is (or was, at least) written in Scala.