alt Hacker News> The bad package version has also just disappeared from crates.io with no indication its been yanked.
So, yanked crate versions do have an indication on crates.io. (Here's an example: [1]) The Rust blog post uses the word "deleted", and I'm guessing a bit here, but I think they mean that literally, and that the version here is deleted, not yanked. And I think that would be more appropriate: a yanked crate is still downloadable by cargo, if your lockfile is locked to it already; yanking only prevents lockfiles from newly automatically acquiring a lock on that version. That wouldn't be desirable in the case of a compromised crate: you don't want a download occurring at all. The tradeoff of "break those with locks on the crate" tips to being worth it.
That said, I agree with you, though: I think this state (if it is "deleted" and not yanked) should be plainly indicated on the crate's versions page. (Even better would be if it came with a link to, e.g., the blog post or a RUSTSEC so that you could find out why.) (& I think perhaps the docs for yank should point out whether or not it is appropriate in the "compromised crate" scenario, and if not, what to do instead.)
> That wouldn't be desirable in the case of a compromised crate: you don't want a download occurring at all.
Sure you do; you just don’t want the crate to be made available to people trying to make use of the crate as regular downstream consumers. You still want the crate available for download for analysis. You especially want to be able to deterministically reproduce the vulnerable version of your software that you already built.
I would posit that most package ecosystems should treat “contains an exploit” as its own package state; mostly ignore them; but still be aware of their existence.
In other words, if there’s any other non-exploited option under your version constraints, the dep should resolve to the nearest non-exploited version, even if older. But if it’s the only version, or if you have pinned the exploited version, then the packager should see it, but normally refuse to interact with it—i.e. refuse to lock to it if it’s the only version; or refuse to fetch it if it’s the locked version.
I say “normally” because you should be able to bypass this with a flag / env-var to the packager that basically means “I’m building this for forensic analysis, not for running.”