| ▲ | chilljinx 5 hours ago | |||||||||||||||||||||||||||||||||||||||||||||||||
Unsafe is not necessary to trigger UB in case no_std is used. Nor if one of the soundness holes in the Rust programming language itself is encountered. Nor if there is UB in one of the libraries used as a dependency by the library you are using. Nor if there is UB in the Rust standard library. Which has happened many times, since the Rust standard library is full of unsafe. Rust also requires libraries to be safe regarding unsafe, no matter what kind of insane input that is given to the library and that would otherwise potentially be security issues. Which is too difficult for many library authors. And unsafe in Rust is so difficult that many library authors throw their hands up, use Miri, and hope for the best. Even though Miri, all respect to it, has bugs, probability-based testing and other limitations and issues. UB in both user library and standard library: https://materialize.com/blog/rust-concurrency-bug-unbounded-... | ||||||||||||||||||||||||||||||||||||||||||||||||||
| ▲ | sunshowers 5 hours ago | parent | next [-] | |||||||||||||||||||||||||||||||||||||||||||||||||
If you are interested in a more nuanced take on what makes unsafe Rust both valuable and difficult, check out my blog post on the Oxide blog: https://oxide.computer/blog/iddqd-unsafe I directly tackle the concerns you mentioned, and as a followup I'm actually working on formally verifying the library as well (I've had some success and will publish an update regarding this). | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| ▲ | Groxx 5 hours ago | parent | prev | next [-] | |||||||||||||||||||||||||||||||||||||||||||||||||
I'm caught somewhere between interpreting this as "C is all we need. git gud" and "rust hurt me and I'm still mad" and I'm struggling to see any other option. It's an unfocused rant that seems keyed off "rust" and little else. In broad strokes it's correct, this stuff happens and it's hard to be correct all the time. But are you trying to make a point? Or just ranting? Also that linked issue was considered a CVE and is fixed (as the article says). | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| ▲ | kllrnohj 5 hours ago | parent | prev | next [-] | |||||||||||||||||||||||||||||||||||||||||||||||||
> Nor if one of the soundness holes in the Rust programming language itself is encountered. imo one of those soundness holes is caused directly from trying to prevent UB - integer overflows. It is inconsistent in Rust what happens in that scenario depending on compiler flags, which basically just makes it UB for any given piece of code. And, unfortunately, default release mode behavior is unsafe. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| ▲ | afdbcreid 5 hours ago | parent | prev | next [-] | |||||||||||||||||||||||||||||||||||||||||||||||||
> Unsafe is not necessary to trigger UB in case no_std is used I have no idea what are you talking about, no_std is just completely irrelevant here. > Nor if one of the soundness holes in the Rust programming language itself is encountered Have you actually examined those soundness holes? It is basically impossible to hit them without writing code which is meant to hit them. And this is also noted in a footnote. > Nor if there is UB in one of the libraries used as a dependency by the library you are using If we treat a Rust program globally, this is kinda true. A more true statement will be that UB cannot happen without unsafe code somewhere, including in dependencies (and the original statement can be interpreted as saying that). But the true power of unsafe is that it's local. If you've reviewed a library and its unsafe is sound, you can ignore it for the rest of the calculation. And of course, the more people review a library the more likely it is that it is sound. > Which has happened many times, since the Rust standard library is full of unsafe And here again the post's point stands: many CVEs in std are artificial, you can't exploit them without writing a program that is meant to be exploited. Such thing will never be a CVE in C/C++'s std. > Rust also requires libraries to be safe regarding unsafe, no matter what kind of insane input that is given to the library and that would otherwise potentially be security issues. Which is too difficult for many library authors. That is true, that is in fact the post's point: that if they fail this, a CVE will be filled, even if exploitation is just not possible realistically. But there is a very simple solution for library authors: don't write unsafe code! You don't need to, the vast majority of times. And if you do not have the knowledge (which indeed is more complicated than in C/C++) how to not have an unsound API, then you just should not write unsafe code. | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| ▲ | slopinthebag 5 hours ago | parent | prev [-] | |||||||||||||||||||||||||||||||||||||||||||||||||
> The fix for this bug is included in Rust 1.87.0 Am I missing something? | ||||||||||||||||||||||||||||||||||||||||||||||||||