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My impression of nix package maintainers is that they are providing a useful interface so that software can be composed easily. Most of them are not making any

My impression of nix package maintainers is that they are providing a useful interface so that software can be composed easily. Most of them are not making any kind of assertion about the contents of the package. Expecting to use their signatures for anything meaningful strikes me as a bit like expecting product support from a delivery driver. You don't need to trust it wasn't packaged maliciously, nix does reproducible builds so you can just look at the derivation and build it yourself if you don't feel like relying on the binary cache. As for whether the underlying contents are malicious, that's between you and the developer. If other distributions have have lead you to believe otherwise, then I think they have misled you. The only exception I can think of is Tails, and they don't exactly have the breadth that Nix does.

lrvick 3y ago
"Expecting to use their signatures for anything meaningful strikes me as a bit like expecting product support from a delivery driver." And yet most of the packages from most major linux distributions are signed. If you are going to spend hours maintaining a package, it takes only an extra half a second to tap a yubikey to prevent someone from impersonating you. Package maintainers from say Arch and Debian go through a vetting process, multiple people sign their keys, and it is a responsibility. Yes, it is volunteer, but there are also volunteer firefighers. Some volunteer jobs are important to keep others safe, and they should be done with care. If Arch, Debian, Fedora, Ubuntu can all sign packages, then this excuse does not really hold for Nix. "You don't need to trust it wasn't packaged maliciously, nix does reproducible builds so you can just look at the derivation and build it yourself if you don't feel like relying on the binary cache." Reproducible builds and package definition signing solve totally different problems. Assume you trust a given developer has been maintaining a package non-maliciously, then you see they made a new update, and so you and other people trust it and build it. You get the same result, so you trust the binaries too. However, you still end up with malware. How? Simple. The developers github account was compromised due to a sim swap on their email account while they were on vacation, and someone pushed a fake commit as that person. Or maybe a malicious Github employee is bribed to serve manipulated git history only to the reproducible build servers but to no one else, so it goes undetected for years. Supply chain attacks like this are becoming very common, and there is a lot of motivation to do it to Linux distributions which power systems worth billions of dollars regularly. It is also so easy to close these risks. Just tap the damn yubikey or nitrokey when it blinks. It is wildly irresponsible not to mandate this, and we should question the motivations of anyone not willing to do something so basic to protect users.
- KingMachiavelli 3y ago
  Nix doesn't have maintainers sign anything because it isn't necessary. The Nix binary cache is built and signed but that's done by builders only the NiXOS foundation controls. Individual maintainers just commit Nix code to build the packages... Do you mean you want their Git commits to be signed? Edit: I guess that is what you mean. That is distinct from package (binary) signing. How do you know that a distro's repos built using the signed commits? NixOS is actually better suited to prove that an particular commit produced the package.
  - lrvick 3y ago
    Two people being able to build the same source and get the same result, does not mean the source that was built was the same source the developer originally contributed. Signing git commits would be a great start, easier than what other distros do to solve the same problem. With reproducible builds in place, the biggest remaining risk is someone tampering with git history. Also packages being built by a central party is actually a problem. What stops someone with ssh access to the build systems from tampering with the results?
    - BreakfastB0b 3y ago
      Nix has two types of derivations (builds). Input addressed, and content addressed. An input addressed derivation’s hash is based on the the hash of all its input derivations and its own derivation. Therefore trusting the association between the cached binary and the derivation requires trusting the builder and a signature. All non-derivation inputs like source code, must be content-addressed. A content addressed derivation can then be produced easily by rewriting all the derivations with `nix make-content-addressed`. This doesn’t require trust / signatures as every stage of the build is now content-addressed. The final hash could be confirmed through social consensus of multiple distrusting parties. There’s nothing in theory stopping you from starting with a content addressed derivation other than it being a pain in the ass as you’d have to know the output hash before you built it, or TOFU (trust on first use) it which is then just the same as using the `nix make-content-addressed` approach. I’m not sure why you think commit signatures are required. Git is content addressed, you can’t tamper with the derivations without changing the hashes and nixpkgs is primarily developed through GitHub. If someone has access to your SSH keys or GitHub account password it stands to reason they’d have access to your GPG keys too.

lrvick 3y ago

"Expecting to use their signatures for anything meaningful strikes me as a bit like expecting product support from a delivery driver." And yet most of the packages from most major linux distributions are signed. If you are going to spend hours maintaining a package, it takes only an extra half a second to tap a yubikey to prevent someone from impersonating you. Package maintainers from say Arch and Debian go through a vetting process, multiple people sign their keys, and it is a responsibility. Yes, it is volunteer, but there are also volunteer firefighers. Some volunteer jobs are important to keep others safe, and they should be done with care. If Arch, Debian, Fedora, Ubuntu can all sign packages, then this excuse does not really hold for Nix. "You don't need to trust it wasn't packaged maliciously, nix does reproducible builds so you can just look at the derivation and build it yourself if you don't feel like relying on the binary cache." Reproducible builds and package definition signing solve totally different problems. Assume you trust a given developer has been maintaining a package non-maliciously, then you see they made a new update, and so you and other people trust it and build it. You get the same result, so you trust the binaries too. However, you still end up with malware. How? Simple. The developers github account was compromised due to a sim swap on their email account while they were on vacation, and someone pushed a fake commit as that person. Or maybe a malicious Github employee is bribed to serve manipulated git history only to the reproducible build servers but to no one else, so it goes undetected for years. Supply chain attacks like this are becoming very common, and there is a lot of motivation to do it to Linux distributions which power systems worth billions of dollars regularly. It is also so easy to close these risks. Just tap the damn yubikey or nitrokey when it blinks. It is wildly irresponsible not to mandate this, and we should question the motivations of anyone not willing to do something so basic to protect users.

KingMachiavelli 3y ago
Nix doesn't have maintainers sign anything because it isn't necessary. The Nix binary cache is built and signed but that's done by builders only the NiXOS foundation controls. Individual maintainers just commit Nix code to build the packages... Do you mean you want their Git commits to be signed? Edit: I guess that is what you mean. That is distinct from package (binary) signing. How do you know that a distro's repos built using the signed commits? NixOS is actually better suited to prove that an particular commit produced the package.
- lrvick 3y ago
  Two people being able to build the same source and get the same result, does not mean the source that was built was the same source the developer originally contributed. Signing git commits would be a great start, easier than what other distros do to solve the same problem. With reproducible builds in place, the biggest remaining risk is someone tampering with git history. Also packages being built by a central party is actually a problem. What stops someone with ssh access to the build systems from tampering with the results?
  - BreakfastB0b 3y ago
    Nix has two types of derivations (builds). Input addressed, and content addressed. An input addressed derivation’s hash is based on the the hash of all its input derivations and its own derivation. Therefore trusting the association between the cached binary and the derivation requires trusting the builder and a signature. All non-derivation inputs like source code, must be content-addressed. A content addressed derivation can then be produced easily by rewriting all the derivations with `nix make-content-addressed`. This doesn’t require trust / signatures as every stage of the build is now content-addressed. The final hash could be confirmed through social consensus of multiple distrusting parties. There’s nothing in theory stopping you from starting with a content addressed derivation other than it being a pain in the ass as you’d have to know the output hash before you built it, or TOFU (trust on first use) it which is then just the same as using the `nix make-content-addressed` approach. I’m not sure why you think commit signatures are required. Git is content addressed, you can’t tamper with the derivations without changing the hashes and nixpkgs is primarily developed through GitHub. If someone has access to your SSH keys or GitHub account password it stands to reason they’d have access to your GPG keys too.