Add a basic daemon authorization test

flake.nix

@@ -499,6 +499,8 @@
           };
 
         # System tests.
+        tests.authorization = runNixOSTestFor "x86_64-linux" ./tests/nixos/authorization.nix;
+
         tests.remoteBuilds = runNixOSTestFor "x86_64-linux" ./tests/nixos/remote-builds.nix;
 
         tests.nix-copy-closure = runNixOSTestFor "x86_64-linux" ./tests/nixos/nix-copy-closure.nix;

tests/nixos/authorization.nix

@@ -0,0 +1,79 @@
+{
+  name = "authorization";
+
+  nodes.machine = {
+    virtualisation.writableStore = true;
+    # TODO add a test without allowed-users setting. allowed-users is uncommon among NixOS users.
+    nix.settings.allowed-users = ["alice" "bob"];
+    nix.settings.trusted-users = ["alice"];
+
+    users.users.alice.isNormalUser = true;
+    users.users.bob.isNormalUser = true;
+    users.users.mallory.isNormalUser = true;
+
+    nix.settings.experimental-features = "nix-command";
+  };
+
+  testScript =
+  let
+    pathFour = "/nix/store/20xfy868aiic0r0flgzq4n5dq1yvmxkn-four";
+  in
+  ''
+    machine.wait_for_unit("multi-user.target")
+    machine.succeed("""
+      exec 1>&2
+      echo kSELDhobKaF8/VdxIxdP7EQe+Q > one
+      diff $(nix store add-file one) one
+    """)
+    machine.succeed("""
+      su --login alice -c '
+        set -x
+        cd ~
+        echo ehHtmfuULXYyBV6NBk6QUi8iE0 > two
+        ls
+        diff $(echo $(nix store add-file two)) two' 1>&2
+    """)
+    machine.succeed("""
+      su --login bob -c '
+        set -x
+        cd ~
+        echo 0Jw8RNp7cK0W2AdNbcquofcOVk > three
+        diff $(nix store add-file three) three
+      ' 1>&2
+    """)
+
+    # We're going to check that a path is not created
+    machine.succeed("""
+      ! [[ -e ${pathFour} ]]
+    """)
+    machine.succeed("""
+      su --login mallory -c '
+        set -x
+        cd ~
+        echo 5mgtDj0ohrWkT50TLR0f4tIIxY > four;
+        (! diff $(nix store add-file four) four 2>&1) | grep -F "cannot open connection to remote store"
+        (! diff $(nix store add-file four) four 2>&1) | grep -F "Connection reset by peer"
+        ! [[ -e ${pathFour} ]]
+      ' 1>&2
+    """)
+
+    # Check that the file _can_ be added, and matches the expected path we were checking
+    machine.succeed("""
+      exec 1>&2
+      echo 5mgtDj0ohrWkT50TLR0f4tIIxY > four
+      four="$(nix store add-file four)"
+      diff $four four
+      diff <(echo $four) <(echo ${pathFour})
+    """)
+
+    machine.succeed("""
+      su --login alice -c 'nix-store --verify --repair'
+    """)
+
+    machine.succeed("""
+      set -x
+      su --login bob -c '(! nix-store --verify --repair 2>&1)' | tee diag 1>&2
+      grep -F "you are not privileged to repair paths" diag
+    """)
+  '';
+}