Nix / NixOS @programming.dev secana @programming.dev 3mo ago

Nix develop shell not using custom TSL certificates

Hi!

I've ran into an issue with nix develop shells.

My setup:

Nix Darwin (macos)
Custom TLS certificates installed via nix darwin

Everything works as expected with the installed certificates, but as soon as I enter into a development shell with nix develop, the certificates are not available and thus, I get TLS errors that break whatever I'm doing in the dev shell. If I use an impure development shell, the issue disappears.

Is there a way to use pure nix develop shells which respect the installed certificates?

5 comments

Could you provide more information? Snippets of the config that are relevant e.g custom TLS certs config, what does the flake look like, self-signed TLS certs? What exactly is breaking? curl https://localhost:8080/something ?

Have you compared the environment variables?

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- It’s almost as if you’d like OP to provide a reproducible example. If only there was a tool for that /s
- Sure. I import the certificates like this:
  
  { config, pkgs, inputs, ... }: { security.pki.certificateFiles = [ ./certificates/home.pem ]; }
  
  where home.pem is a default PEM formatted certificate. It works fine to import the cert system wide this way.
  
  If I enter the flake.nix and run a simple curl against the remote server I get the following, which is typical for a TLS certificate error.
  
  curl https://webpage.home curl: (35) OpenSSL/3.0.14: error:16000069:STORE routines::unregistered scheme
  
  So it seems to me that the development shell does not pick up the certificates installed on the system. I can work around that by using an impure shell, but I think that this is not how nix should be used.
  
  So the certs end up in these files:
  
  /etc/ssl/certs/ca-certificates.crt
  
  /etc/ssl/certs/ca-bundle.crt
  
  / etc/pki/tls/certs/ca-bundle.crt
  
  Only the first one is mentioned on stackoverflow as being used by Go on debian.
  
  Curl seems to have its default location compiled in by passing --with-ca-bundle ~~, but after installing curlFull and running curl-config --ca, it doesn't look like that was used and the "default" path is guessed.~~
  
  Looking further in the curl derivation there are these lines for darwin :
  
  lib.optionals stdenv.isDarwin [ # Disable default CA bundle, use NIX_SSL_CERT_FILE or fallback to nss-cacert from the default profile. # Without this curl might detect /etc/ssl/cert.pem at build time on macOS, causing curl to ignore NIX_SSL_CERT_FILE. "--without-ca-bundle" "--without-ca-path" ]
  
  So, check the value of NIX_SSL_CERT_FILE outside nix shell and within. The path might have to be set there. I dunno how to do that automatically with nix shell, so it might have to be done manually.
  
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