[mirashii]

None of the criticisms of package signing here apply in this case. Package signing does cover this exact issue, which we should describe to be specific:

(1) someone has published a package. (2) that package has become well known and used enough that the community as a whole trusts that the entity publishing that package is not there for malicious purposes (3) the maintainer of that package has their account compromised, either by credential leak or by a vulnerability in the package management system itself (in this case, the former and not the latter)

If the package were signed, then the attacker could not have published this fake package that lead to issues today. Does this solve the root chain of trust issue for whose packages you should trust? No, but nothing other than thoroughly reviewing every line can do that. Does it prevent you from having a random unknown person masquerade as the maintainer and publish a malicious package? Yes.

There are real additional trust issues to solve, but let's not let those detract from the fact that package signing would have prevented the exact issue which we saw today. Defense in depth, always.

[hyperpape]

I'm not going to say that you're wrong in any particular thing you said. You are correct that package signing would have prevented this exact issue we saw today, and I'm not opposed to an argument for defense in depth.

However, I am going to reiterate my original point with a bit of clarification: "it is not clear that package signing will prevent malicious actors from compromising systems using a language package manager with anything approaching the success of distro package managers".

I think what you're proposing amounts to a two-tier system. There is somehow a set of known signatures that are trusted by the npm consumer[0] and then a vast sea of untrusted signatures. Developers sometimes add libraries, and add one (or more?) signatures to their trusted set.

First, in the specific case of NPM, we have an existing system with huge numbers of transitive dependencies and no existing package signing. I don't see how you retrofit signing on to that system. Too many developers will ignore it, but also because there are so many libraries, you'll have an absolutely massive number of trusted keys.

Second, suppose you're starting from scratch, so you can enforce signatures from day one. You still have the problem of transitive dependencies. It's certainly more work for a malicious actor to either a) create legitimate libraries that will be included in other libraries, then convert them to malware, or b) steal a developer's signing keys, but neither one is remotely impossible, given the large number of libraries involved. You just need one part of that web of libraries to involve a sloppy or malicious developer, and you are hosed.

[0] Interesting question: how is this handled? Is it part of the lockfile for a project? Something system level, with the problems of devs installing random shit on their machines and ending up with too much being trusted, and also lack of reproducible builds?