1 files changed, 108 insertions, 0 deletions
diff --git a/third_party/nix/tests/setuid.nix b/third_party/nix/tests/setuid.nix
new file mode 100644
index 0000000000..77e83c8d6c
--- /dev/null
+++ b/third_party/nix/tests/setuid.nix
@@ -0,0 +1,108 @@
+# Verify that Linux builds cannot create setuid or setgid binaries.
+
+{ nixpkgs, system, nix }:
+
+with import (nixpkgs + "/nixos/lib/testing.nix") { inherit system; };
+
+makeTest {
+
+  machine =
+    { config, lib, pkgs, ... }:
+    { virtualisation.writableStore = true;
+      nix.package = nix;
+      nix.binaryCaches = [ ];
+      nix.nixPath = [ "nixpkgs=${lib.cleanSource pkgs.path}" ];
+      virtualisation.pathsInNixDB = [ pkgs.stdenv pkgs.pkgsi686Linux.stdenv ];
+    };
+
+  testScript = { nodes }:
+    ''
+      startAll;
+
+      # Copying to /tmp should succeed.
+      $machine->succeed('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" {} "
+        mkdir -p $out
+        cp ${pkgs.coreutils}/bin/id /tmp/id
+      ")\' ');
+
+      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
+
+      $machine->succeed("rm /tmp/id");
+
+      # Creating a setuid binary should fail.
+      $machine->fail('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" {} "
+        mkdir -p $out
+        cp ${pkgs.coreutils}/bin/id /tmp/id
+        chmod 4755 /tmp/id
+      ")\' ');
+
+      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
+
+      $machine->succeed("rm /tmp/id");
+
+      # Creating a setgid binary should fail.
+      $machine->fail('nix-build --no-sandbox -E \'(with import <nixpkgs> {}; runCommand "foo" {} "
+        mkdir -p $out
+        cp ${pkgs.coreutils}/bin/id /tmp/id
+        chmod 2755 /tmp/id
+      ")\' ');
+
+      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
+
+      $machine->succeed("rm /tmp/id");
+
+      # The checks should also work on 32-bit binaries.
+      $machine->fail('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
+      ")\' ');
+
+      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
+
+      $machine->succeed("rm /tmp/id");
+
+      # The tests above use fchmodat(). Test chmod() as well.
+      $machine->succeed('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\"
+      ")\' ');
+
+      $machine->succeed('[[ $(stat -c %a /tmp/id) = 666 ]]');
+
+      $machine->succeed("rm /tmp/id");
+
+      $machine->fail('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\"
+      ")\' ');
+
+      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
+
+      $machine->succeed("rm /tmp/id");
+
+      # And test fchmod().
+      $machine->succeed('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\"
+      ")\' ');
+
+      $machine->succeed('[[ $(stat -c %a /tmp/id) = 1750 ]]');
+
+      $machine->succeed("rm /tmp/id");
+
+      $machine->fail('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\"
+      ")\' ');
+
+      $machine->succeed('[[ $(stat -c %a /tmp/id) = 555 ]]');
+
+      $machine->succeed("rm /tmp/id");
+    '';
+
+}