get rid systemd patches

README.md

@@ -96,6 +96,14 @@ files: `systemd-vaultd.service`, `systemd-vaultd.socket`:
 make install
 ```
 
+## Known limitations
+
+systemd's LoadCredential option will not update credentials if a service is
+reloaded. However systemd-vaultd called `systemd-vaultd-update-secrets` comes
+with a helper program that can write secrets from the json file generated by
+systemd-vaultd to a directory readable by the service. Checkout
+`systemd-vaultd/nix/checks/systemd-vaultd-test.nix` for more details.
+
 ## License
 
 Copyright (c) 2022 [Jörg Thalheim](https://github.com/mic92) and contributors.

cmd/systemd-vaultd-update-secrets/main.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path"
+	"syscall"
+	"time"
+)
+
+const (
+	systemdVaultdir = "/run/systemd-vaultd/secrets"
+)
+
+func updateSecrets(credentialsDirectory, target string) error {
+	// get systemd service name from credentials directory
+	serviceName := path.Base(credentialsDirectory)
+	stat, err := os.Stat(credentialsDirectory)
+	if err != nil {
+		return fmt.Errorf("failed to stat %s: %w", credentialsDirectory, err)
+	}
+	// inherit the owner and group of the credentials directory
+	uid := stat.Sys().(*syscall.Stat_t).Uid
+	gid := stat.Sys().(*syscall.Stat_t).Gid
+
+	jsonPath := path.Join(credentialsDirectory, fmt.Sprintf("%s.json", serviceName))
+	var content []byte
+	for i := 0; i < 10; i++ {
+		content, err = os.ReadFile(jsonPath)
+		if err != nil {
+			if os.IsNotExist(err) {
+				// wait for the file to be created
+				fmt.Printf("waiting for %s to be created", jsonPath)
+				time.Sleep(1 * time.Second)
+				continue
+			}
+			return fmt.Errorf("failed to read vault json file %s: %w", serviceName, err)
+		}
+		break
+	}
+	var data map[string]interface{}
+	if err := json.Unmarshal(content, &data); err != nil {
+		return fmt.Errorf("failed to unmarshal json from %s: %w", jsonPath, err)
+	}
+	for key, value := range data {
+		targetPath := path.Join(target, key)
+		err := os.MkdirAll(path.Dir(targetPath), 0o700)
+		os.Chown(path.Dir(targetPath), int(uid), int(gid))
+
+		if err != nil {
+			return fmt.Errorf("failed to create directory %s: %w", path.Dir(targetPath), err)
+		}
+		os.WriteFile(targetPath, []byte(value.(string)), 0o400)
+		os.Chown(targetPath, int(uid), int(gid))
+	}
+
+	return nil
+}
+
+func main() {
+	if len(os.Args) != 2 {
+		fmt.Println("Usage: systemd-vaultd-update-secrets <target>")
+		os.Exit(1)
+	}
+	credentialsDirectory := os.Getenv("CREDENTIALS_DIRECTORY")
+	if credentialsDirectory == "" {
+		fmt.Println("CREDENTIALS_DIRECTORY environment variable must be set")
+		os.Exit(1)
+	}
+
+	target := os.Args[1]
+	if err := updateSecrets(credentialsDirectory, target); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}

flake.nix

@@ -22,7 +22,6 @@
         , ...
         }: {
           packages.default = pkgs.callPackage ./default.nix { };
-          packages.systemd = pkgs.callPackage ./nix/pkgs/systemd.nix { };
           devShells.default = pkgs.mkShellNoCC {
             buildInputs = with pkgs; [
               python3.pkgs.pytest
@@ -35,7 +34,6 @@
               go
               just
               config.treefmt.build.wrapper
-              config.packages.systemd
             ];
           };
 

nix/checks/systemd-vaultd-test.nix

@@ -2,7 +2,6 @@
   name = "systemd-vaultd";
   nodes.server =
     { config
-    , pkgs
     , ...
     }: {
       imports = [
@@ -10,6 +9,9 @@
         ../modules/systemd-vaultd.nix
         ./dev-vault-server.nix
       ];
+      # speed up tests
+      virtualisation.cores = 4;
+      virtualisation.memorySize = 1024;
 
       systemd.services.service1 = {
         wantedBy = [ "multi-user.target" ];
@@ -33,17 +35,33 @@
         };
       };
 
+      users.users.service2 = {
+        isSystemUser = true;
+        group = "service2";
+        uid = 1000;
+      };
+      users.groups.service2.gid = 1000;
+
       systemd.services.service2 = {
         wantedBy = [ "multi-user.target" ];
+        preStart = ''
+          cp -r $CREDENTIALS_DIRECTORY /run/service2/secrets
+        '';
         script = ''
           set -x
           while true; do
-            cat $CREDENTIALS_DIRECTORY/secret > /tmp/service2
+            cat /run/service2/secrets/secret >&2 || :
+            cat /run/service2/secrets/secret > /tmp/service2 || :
             sleep 0.1
           done
         '';
-        serviceConfig.ExecReload = "${pkgs.coreutils}/bin/true";
-        serviceConfig.LoadCredential = [ "secret:/run/systemd-vaultd/sock" ];
+        serviceConfig = {
+          ExecReload = "+${config.services.systemd-vaultd.package}/bin/systemd-vaultd-update-secrets /run/service2/secrets";
+          User = "service2";
+          Group = "service2";
+          LoadCredential = [ "secret:/run/systemd-vaultd/sock" ];
+          RuntimeDirectory = "service2";
+        };
         vault = {
           template = ''
             {{ with secret "secret/blocking-secret" }}{{ scratch.MapSet "secrets" "secret" .Data.data.foo }}{{ end }}
@@ -77,32 +95,37 @@
     machine.wait_for_open_port(8200)
     machine.wait_for_unit("setup-vault-agent-approle.service")
 
-    out = machine.wait_until_succeeds("cat /tmp/service1")
-    print(out)
-    assert out == "bar", f"{out} != bar for service1"
+    out = machine.wait_until_succeeds("grep -q bar /tmp/service1")
 
-    out = machine.succeed("cat /tmp/service1-env")
-    print(out)
-    assert out == "bar", f"{out} != bar for service1-env"
+    out = machine.succeed("grep -q bar /tmp/service1-env")
 
-    out = machine.succeed("systemctl status service2")
+    out = machine.succeed("systemctl status service2 || :")
     print(out)
     assert "(sd-mkdcreds)" in out, "service2 should be still blocked"
 
     machine.succeed("vault kv put secret/blocking-secret foo=bar")
-    out = machine.wait_until_succeeds("cat /tmp/service2")
-    print(out)
-    assert out == "bar", f"{out} != bar for service2"
+    machine.wait_until_succeeds("grep -q bar /tmp/service2 >&2")
 
-    machine.succeed("vault kv put secret/blocking-secret foo=reload")
+    machine.succeed("umount /run/credentials/service2.service")
     machine.succeed("rm /run/systemd-vaultd/secrets/service2.service.json")
+
+    machine.succeed("vault kv put secret/blocking-secret foo=reload")
+
     machine.succeed("systemctl restart vault-agent-default")
     machine.wait_until_succeeds("cat /run/systemd-vaultd/secrets/service2.service.json >&2")
-    machine.succeed("systemctl reload service2")
+    machine.succeed("systemctl restart service2")
 
     machine.succeed("rm /tmp/service2")
-    out = machine.wait_until_succeeds("cat /tmp/service2")
-    print(out)
-    assert out == "reload", f"{out} != reload for service2"
+    machine.wait_until_succeeds("grep -q reload /tmp/service2 >&2")
+
+    # get uid and gid
+    out = machine.succeed("stat -c %u /run/service2/secrets/secret").strip()
+    assert out == "1000", "service2 should have access to secret file with uid 1000, got " + out
+    out = machine.succeed("stat -c %g /run/service2/secrets/secret").strip()
+    assert out == "1000", "service2 should have access to secret file with gid 1000, got " + out
+
+    # get permissions in octal
+    out = machine.succeed("stat -c %a /run/service2/secrets/secret").strip()
+    assert out == "400", "service2 should have access to secret file with permissions 0400, got " + out
   '';
 }

nix/checks/unittests.nix

@@ -3,11 +3,10 @@
 , pkgs
 , lib
 , coreutils
-,
+, systemd
 }:
 let
   systemd-vaultd = pkgs.callPackage ../../default.nix { };
-  systemd = pkgs.callPackage ../pkgs/systemd.nix { };
 in
 writeShellScript "unittests" ''
   set -eu -o pipefail

nix/modules/systemd-vaultd.nix

@@ -1,4 +1,6 @@
 { pkgs
+, lib
+, config
 , ...
 }:
 let
@@ -8,9 +10,20 @@ in
   imports = [
     ./vault-secrets.nix
   ];
+  options = {
+    services.systemd-vaultd = {
+      package = lib.mkOption {
+        type = lib.types.package;
+        default = systemd-vaultd;
+        defaultText = "pkgs.systemd-vaultd";
+        description = ''
+          The package to use for systemd-vaultd
+        '';
+      };
+    };
+  };
 
-  systemd.package = pkgs.callPackage ../pkgs/systemd.nix { };
-
+  config = {
     systemd.sockets.systemd-vaultd = {
       description = "systemd-vaultd socket";
       wantedBy = [ "sockets.target" ];
@@ -28,7 +41,8 @@ in
       # Restarting can break services waiting for secrets
       stopIfChanged = false;
       serviceConfig = {
-      ExecStart = "${systemd-vaultd}/bin/systemd-vaultd";
+        ExecStart = "${config.services.systemd-vaultd.package}/bin/systemd-vaultd";
+      };
     };
   };
 }

nix/pkgs/systemd.nix

@@ -1,14 +0,0 @@
-{ systemd
-, fetchpatch
-,
-}:
-systemd.overrideAttrs (old: {
-  patches =
-    old.patches
-    ++ [
-      (fetchpatch {
-        url = "https://github.com/Mic92/systemd/commit/93a2921a81cab3be9b7eacab6b0095c96a0ae9e2.patch";
-        sha256 = "sha256-7WlhMLE7sfD3Cxn6n6R1sUNzUOvas7XMyabi3bsq7jM=";
-      })
-    ];
-})