MIRAI
no-panic
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MIRAI | no-panic | |
---|---|---|
9 | 12 | |
959 | 515 | |
1.7% | - | |
0.0 | 4.2 | |
4 months ago | about 2 years ago | |
Rust | Rust | |
MIT License | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
MIRAI
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Is there something like "super-safe" rust?
MIRAI
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Adding “invariant” clauses to C++ via GCC plugin to enable Design-by-Contract
Do you use the Cargo "contracts" for Design-by-Contract style invariants that plugs into Facebook's MIRAI prover thing?
I always thought it this was super neat:
https://crates.io/crates/contracts
https://github.com/facebookexperimental/MIRAI/blob/main/exam...
[dependencies]
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Prusti: Static Analyzer for Rust
Here's a 2020 overview of Rust verification tools https://alastairreid.github.io/rust-verification-tools/ - it says
> Auto-active verification tools
> While automatic tools focus on things not going wrong, auto-active verification tools help you verify some key properties of your code: data structure invariants, the results of functions, etc. The price that you pay for this extra power is that you may have to assist the tool by adding function contracts (pre/post-conditions for functions), loop invariants, type invariants, etc. to your code.
> The only auto-active verification tool that I am aware of is Prusti. Prusti is a really interesting tool because it exploits Rust’s unusual type system to help it verify code. Also Prusti has the slickest user interface: a VSCode extension that checks your code as you type it!
> https://marketplace.visualstudio.com/items?itemName=viper-ad...
Now, on that list, there is also https://github.com/facebookexperimental/MIRAI that, alongside the crate https://crates.io/crates/contracts (with the mirai_assertion feature enabled) enables writing code like this
#[ensures(person_name.is_some() -> ret.contains(person_name.unwrap()))]
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Ten Years of TypeScript
Traditional design by contract checks the contracts at runtime. They can be understood as a form of dynamic typing with quite complicated types, which may be equivalent to refinement types
But you can check contracts at compile time too. It's quite the same thing as static typing with something like refinement types. That's because, while with contracts we can add preconditions like "the size of this array passed as parameter must be a prime number", with refinement types we can define the type of arrays whose size is a prime number, and then have this type as the function argument. (likewise, postconditions can be modeled by the return type of the function)
See for example this Rust library: https://docs.rs/contracts/latest/contracts/
It will by default check the contracts at runtime, but has an option to check them at compile time with https://github.com/facebookexperimental/MIRAI
Now, this Rust library isn't generally understood as creating another type system on top of Rust, but we could do the legwork to develop a type theory that models how it works, and show the equivalence.
Or, another example, Liquid Haskell: https://ucsd-progsys.github.io/liquidhaskell/ it implements a variant of refinement types called liquid types, which is essentially design by contract checked at compile type. In this case, the type theory is already developed. I expect Liquid Haskell to be roughly comparable to Rust's contracts checked by MIRAI.
Now, what we could perhaps say is that refinement types are so powerful that they don't feel like regular types! And, while that's true, there are type systems even more powerful: dependent types used in languages like Coq, Lean and F* to prove mathematical theorems (your type is a theorem, and your code, if it typechecks, is a proof of that theorem).
Dependent types were leveraged to create a verified TLS implementation that mathematically proves the absence of large class of bugs, miTLS https://www.mitls.org/ (they discovered a number of vulnerabilities in TLS implementations and proved that their implementation isn't vulnerable), and HACL* https://github.com/hacl-star/hacl-star a verified crypto implementation used by Firefox and Wireguard. They are part of Project Everest https://project-everest.github.io/ which aims to develop provably secure communications software.
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A pair of Linux kernel modules using Rust
Because it's convenient and familiar to most programmers. Not providing bounds-checked indexing makes some kinds of code very hard to write.
But note his problem also happens with integer division.
In Rust, a[x] on an array or vec is really a roughly a shortand for a.get(x).unwrap() (with a different error message)
Likewise, a / b on integers is a kind of a shortand for a.checked_div(b).unwrap()
The thing is, if the index ever is out of bounds, or if the denominator is zero, the program has a bug, 100% of time. And if you catch a bug using an assertion there is seldom anything better than interrupting the execution (the only thing I can think of is restarting the program or the subsystem). If you continue execution past a programming error, you may sometimes corrupt data structures or introduce bizarre, hard to debug situations.
Doing a pattern match on a.get(x) doesn't help because if it's ever None (and your program logic expects that x is in bounds) then you are kind of forced to bail.
The downside here is that we aren't catching this bug at compile time. And it's true that sometimes we can rewrite the program to not have an indexing operation, usually using iterators (eliding the bounds check will make the program run faster, too). But in general this is not possible, at least not without bringing formal methods. But that's what tests are for, to ensure the correctness of stuff type errors can't catch.
Now, there are some crates like https://github.com/dtolnay/no-panic or https://github.com/facebookexperimental/MIRAI that will check that your code is panic free. The first one is based on the fact that llvm optimizations can often remove dead code and thus remove the panic from a[x] or a / b - if it doesn't, then compilation fails. The second one employs formal methods to mathematically prove that there is no panic. I guess those techniques will eventually be ported to the kernel even if panics happen differently there (by hooking on the BUG mechanism or whatever)
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Does Rust not need extra linting and sanitizing tools like C++?
There's a MIR Abstract interpreter project: https://github.com/facebookexperimental/MIRAI
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Kani Rust Verifier – a bit-precise model-checker for Rust
Nice, I just would have liked to get all these different verification tools combined under the same interface, just being different backends as drafted by the rust verification tools work of project oak: have "cargo verify" as common command and use common test annotations, allowing the same test to be verified with different backends or just fuzzed/proptested.
The model checking approach seems to be a bit limited regarding loops. There are also abstract interpreters, such as https://github.com/facebookexperimental/MIRAI, and symbolic executers, such as https://github.com/dwrensha/seer or https://github.com/GaloisInc/crucible.
Overall I believe this space would benefit from more coordination and focus on developing something that has the theoretical foundations to cover as many needs as possible and then make a user-friendly tool out of it that is endorsed by the Rust project similar to how Rust analyzer is the one language server to come.
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Things I hate about Rust, redux
https://github.com/facebookexperimental/MIRAI which integrates with https://crates.io/crates/contracts (a crate that does runtime checking of contracts, and with mirai they are upgraded to compile-time checking) and https://crates.io/crates/mirai-annotations
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Is Rust Used Safely by Software Developers?
With the mirai_assertions feature, it can use the MIRAI static analyzer (though it requires nightly).
no-panic
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no_panic causing errors in hello world?
I discovered a crate called no_panic that prevents a function from compiling, unless the compiler can proof that this function can't panic.
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Is there something like "super-safe" rust?
/u/dtolnay has a no-panic macro, I don't know its limitations but in older comments they note it pretty much has to be used in release mode, as there are lots of panic codepaths which get optimised out.
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Is Rust really safe? How to identify functions that can potentially cause panic
'Hacks' such as https://github.com/dtolnay/no-panic, https://crates.io/crates/no-panics-whatsoever that ensure any calls to panic handling will result in link errors. Not really reliable in terms of being able to abort instead, but a possible tool.
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US NGO Consumer Reports also reporting on C and C++ safety for product development.
nope. Unfortunately, no mainstream language has this yet. We need an Algebraic effects typesystem to do this properly. There are a few temporary band-aid solutions like https://github.com/dtolnay/no-panic
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Carefully exploring Rust as a Python developer
This kind of already exists in the form of #[no_panic] [1]?
> If the function does panic (or the compiler fails to prove that the function cannot panic), the program fails to compile with a linker error that identifies the function name.
1: https://github.com/dtolnay/no-panic
- What I like about rust
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LKML: Linus Torvalds: Re: [PATCH v9 12/27] rust: add `kernel` crate
I really think that Rust needs an official #[no_panic] macro that can validate these sort of things (like dtolnay’s crate, I’m not sure why it was archived)
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A pair of Linux kernel modules using Rust
Because it's convenient and familiar to most programmers. Not providing bounds-checked indexing makes some kinds of code very hard to write.
But note his problem also happens with integer division.
In Rust, a[x] on an array or vec is really a roughly a shortand for a.get(x).unwrap() (with a different error message)
Likewise, a / b on integers is a kind of a shortand for a.checked_div(b).unwrap()
The thing is, if the index ever is out of bounds, or if the denominator is zero, the program has a bug, 100% of time. And if you catch a bug using an assertion there is seldom anything better than interrupting the execution (the only thing I can think of is restarting the program or the subsystem). If you continue execution past a programming error, you may sometimes corrupt data structures or introduce bizarre, hard to debug situations.
Doing a pattern match on a.get(x) doesn't help because if it's ever None (and your program logic expects that x is in bounds) then you are kind of forced to bail.
The downside here is that we aren't catching this bug at compile time. And it's true that sometimes we can rewrite the program to not have an indexing operation, usually using iterators (eliding the bounds check will make the program run faster, too). But in general this is not possible, at least not without bringing formal methods. But that's what tests are for, to ensure the correctness of stuff type errors can't catch.
Now, there are some crates like https://github.com/dtolnay/no-panic or https://github.com/facebookexperimental/MIRAI that will check that your code is panic free. The first one is based on the fact that llvm optimizations can often remove dead code and thus remove the panic from a[x] or a / b - if it doesn't, then compilation fails. The second one employs formal methods to mathematically prove that there is no panic. I guess those techniques will eventually be ported to the kernel even if panics happen differently there (by hooking on the BUG mechanism or whatever)
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Redoing the runtime
Hmm, yeah as you mentioned, looks like a surprising amount of stuff is already done in the rust for the linux kernel project: https://github.com/Rust-for-Linux/linux/tree/rust/rust/. It's also MIT/Apache licensed, but I was expecting gpl, so I can actually use it. It's still a lot to trim down on, so might be easier to just build up as needed. Additionally I just saw /u/dtolnay's #[no_panic] attribute which at least makes it a compiler error if it's accidentally done.
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[PATCH 00/13] [RFC] Rust support
Obviously, in bare metal systems, in the kernel, etc, you always want to use the second style. In this patch series, the first type had been stubbed out to panic, but Linus doesn't want any chance of panicking, he wants it to be a compile time error if anyone tries to call these methods from within the kernel, for example by not providing the symbols and failing to link if someone did try to use them. There is already precedent for doing that in the Rust ecosystem, so it's planned to do that in this patch series, but the authors hadn't gotten to that yet.
What are some alternatives?
rust-on-raspberry-pi
Rust-for-Linux - Adding support for the Rust language to the Linux kernel.
prusti-dev - A static verifier for Rust, based on the Viper verification infrastructure.
rust - Empowering everyone to build reliable and efficient software.
rust-mode - Emacs configuration for Rust
gccrs - GCC Front-End for Rust
kani - Kani Rust Verifier
rust - Rust language bindings for TensorFlow
just - 🤖 Just a command runner
rustc_codegen_gcc - libgccjit AOT codegen for rustc
Rustup - The Rust toolchain installer
rfcs - RFCs for changes to Rust