# Verify that Linux builds cannot create setuid or setgid binaries. { lib, config, nixpkgs, ... }: let pkgs = config.nodes.machine.nixpkgs.pkgs; in { name = "setuid"; nodes.machine = { config, lib, pkgs, ... }: { virtualisation.writableStore = true; nix.settings.substituters = lib.mkForce [ ]; nix.nixPath = [ "nixpkgs=${lib.cleanSource pkgs.path}" ]; virtualisation.additionalPaths = [ pkgs.stdenvNoCC pkgs.pkgsi686Linux.stdenvNoCC ]; }; testScript = { nodes }: '' # fmt: off start_all() # Copying to /tmp should succeed. machine.succeed(r""" nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" {} " mkdir -p $out cp ${pkgs.coreutils}/bin/id /tmp/id ")' """.strip()) machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]') machine.succeed("rm /tmp/id") # Creating a setuid binary should fail. machine.fail(r""" nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" {} " mkdir -p $out cp ${pkgs.coreutils}/bin/id /tmp/id chmod 4755 /tmp/id ")' """.strip()) machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]') machine.succeed("rm /tmp/id") # Creating a setgid binary should fail. machine.fail(r""" nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" {} " mkdir -p $out cp ${pkgs.coreutils}/bin/id /tmp/id chmod 2755 /tmp/id ")' """.strip()) machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]') machine.succeed("rm /tmp/id") # The checks should also work on 32-bit binaries. machine.fail(r""" nix-build --no-sandbox -E '(with import <nixpkgs> { system = "i686-linux"; }; runCommand "foo" {} " mkdir -p $out cp ${pkgs.coreutils}/bin/id /tmp/id chmod 2755 /tmp/id ")' """.strip()) machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]') machine.succeed("rm /tmp/id") # The tests above use fchmodat(). Test chmod() as well. machine.succeed(r""" nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } " mkdir -p $out cp ${pkgs.coreutils}/bin/id /tmp/id perl -e \"chmod 0666, qw(/tmp/id) or die\" ")' """.strip()) machine.succeed('[[ $(stat -c %a /tmp/id) = 666 ]]') machine.succeed("rm /tmp/id") machine.fail(r""" nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } " mkdir -p $out cp ${pkgs.coreutils}/bin/id /tmp/id perl -e \"chmod 04755, qw(/tmp/id) or die\" ")' """.strip()) machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]') machine.succeed("rm /tmp/id") # And test fchmod(). machine.succeed(r""" nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } " mkdir -p $out cp ${pkgs.coreutils}/bin/id /tmp/id perl -e \"my \\\$x; open \\\$x, qw(/tmp/id); chmod 01750, \\\$x or die\" ")' """.strip()) machine.succeed('[[ $(stat -c %a /tmp/id) = 1750 ]]') machine.succeed("rm /tmp/id") machine.fail(r""" nix-build --no-sandbox -E '(with import <nixpkgs> {}; runCommand "foo" { buildInputs = [ perl ]; } " mkdir -p $out cp ${pkgs.coreutils}/bin/id /tmp/id perl -e \"my \\\$x; open \\\$x, qw(/tmp/id); chmod 04777, \\\$x or die\" ")' """.strip()) machine.succeed('[[ $(stat -c %a /tmp/id) = 555 ]]') machine.succeed("rm /tmp/id") ''; }