Stop sandboxing remote shells

tests/integration_smoke.rs

@@ -2518,6 +2518,9 @@ fn write_persistent_server_config(dir: &tempfile::TempDir, port: u16) -> std::pa
     let mut raw = fs::read_to_string(&config).unwrap();
     // The base writer hardcodes `persist_sessions = false`; flip it on.
     raw = raw.replace("persist_sessions = false", "persist_sessions = true");
+    // Persistence tests attach the sessions they need explicitly. Leaving the
+    // base prewarm on here creates a detached default holder in every test.
+    raw = raw.replace("prewarm_sessions = [\"default\"]", "prewarm_sessions = []");
     fs::write(&config, raw).unwrap();
     config
 }
@@ -2553,6 +2556,45 @@ fn kill_holder(sessions_dir: &Path, session: &str) {
         .status();
 }
 
+/// Create a holder the way older Dosh builds did for implicit sessions, so
+/// startup migration can be tested without depending on the new spawn policy.
+fn spawn_legacy_holder(sessions_dir: &Path, session: &str) {
+    let server = env!("CARGO_BIN_EXE_dosh-server");
+    let runtime_dir = dosh::persist::ensure_runtime_dir(sessions_dir, session).unwrap();
+    let mut launcher = Command::new(server)
+        .arg("hold")
+        .arg("--runtime-dir")
+        .arg(&runtime_dir)
+        .arg("--session")
+        .arg(session)
+        .arg("--shell")
+        .arg("/bin/sh")
+        .arg("--cols")
+        .arg("80")
+        .arg("--rows")
+        .arg("24")
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .spawn()
+        .unwrap();
+    let deadline = std::time::Instant::now() + Duration::from_secs(5);
+    while std::time::Instant::now() < deadline {
+        if holder_shell_pid(sessions_dir, session).is_some()
+            && runtime_dir.join("holder.sock").exists()
+        {
+            let _ = launcher.wait();
+            return;
+        }
+        if let Some(status) = launcher.try_wait().unwrap() {
+            panic!("legacy holder launcher exited before ready: {status}");
+        }
+        thread::sleep(Duration::from_millis(20));
+    }
+    let _ = launcher.kill();
+    let _ = launcher.wait();
+    panic!("legacy holder did not become ready");
+}
+
 /// Send one encrypted Input line and give the shell a moment to act.
 fn type_line(socket: &UdpSocket, port: u16, ok: &AttachOk, key: &[u8; 32], seq: u64, line: &str) {
     let input = Input {
@@ -2690,7 +2732,7 @@ fn session_survives_server_restart_same_shell_and_screen() {
 }
 
 #[test]
-fn implicit_session_survives_server_restart_for_same_ticket_holder() {
+fn implicit_session_does_not_create_restart_holder() {
     let dir = tempfile::tempdir().unwrap();
     let sessions_dir = dir.path().join("sessions");
     let port = free_udp_port();
@@ -2713,20 +2755,14 @@ fn implicit_session_survives_server_restart_for_same_ticket_holder() {
 
     let shell_pid_before = holder_shell_pid(&sessions_dir, &session);
     assert!(
-        shell_pid_before.is_some(),
-        "implicit sessions should get a persistent holder when persistence is enabled"
+        shell_pid_before.is_none(),
+        "implicit sessions must not get persistent holders when persistence is enabled"
     );
 
     let _ = server.kill();
     let _ = server.wait();
     thread::sleep(Duration::from_millis(300));
 
-    let pid = shell_pid_before.unwrap();
-    assert!(
-        unsafe { libc::kill(pid, 0) } == 0,
-        "implicit session shell pid {pid} must survive server restart"
-    );
-
     let mut server = start_server(&dir, &config);
     let (socket2, bootstrap2, ok2) = direct_attach_session(&config, port, "read-write", &session);
     let key2 = bootstrap2.session_key;
@@ -2743,15 +2779,44 @@ fn implicit_session_survives_server_restart_for_same_ticket_holder() {
 
     let _ = server.kill();
     let _ = server.wait();
-    kill_holder(&sessions_dir, &session);
 
-    assert_eq!(
-        shell_pid_after, shell_pid_before,
-        "implicit session should re-adopt the same shell pid"
+    assert!(
+        shell_pid_after.is_none(),
+        "implicit restart attach must stay ephemeral"
     );
     assert!(
-        post.contains("IMPLICIT_MARK=implicit_restart_42"),
-        "implicit session state must survive restart, got {post:?}"
+        post.contains("IMPLICIT_MARK=") && !post.contains("implicit_restart_42"),
+        "implicit session must start fresh after server restart, got {post:?}"
+    );
+}
+
+#[test]
+fn startup_discards_legacy_implicit_holders() {
+    let dir = tempfile::tempdir().unwrap();
+    let sessions_dir = dir.path().join("sessions");
+    let port = free_udp_port();
+    let config = write_persistent_server_config(&dir, port);
+    let session = protocol::generate_implicit_session_name();
+
+    spawn_legacy_holder(&sessions_dir, &session);
+    let shell_pid = holder_shell_pid(&sessions_dir, &session).expect("legacy holder shell pid");
+    assert!(
+        unsafe { libc::kill(shell_pid, 0) } == 0,
+        "legacy holder shell must be live before startup"
+    );
+
+    let mut server = start_server(&dir, &config);
+    thread::sleep(Duration::from_millis(300));
+
+    let _ = server.kill();
+    let _ = server.wait();
+    assert!(
+        holder_shell_pid(&sessions_dir, &session).is_none(),
+        "startup must remove old implicit holder metadata"
+    );
+    assert!(
+        unsafe { libc::kill(shell_pid, 0) } != 0,
+        "startup must shut down old implicit holder shell"
     );
 }
 

tests/release_scripts.rs

@@ -20,13 +20,29 @@ fn release_scripts_skip_stale_artifacts_when_auto_discovering() {
 }
 
 #[test]
-fn systemd_sandbox_allows_netlink_for_terminal_tools() {
+fn systemd_service_does_not_sandbox_remote_shells() {
     let service = include_str!("../packaging/systemd/dosh-server.service");
     let install = include_str!("../install.sh");
     for raw in [service, install] {
+        assert!(raw.contains("KillMode=process"));
+        for directive in [
+            "NoNewPrivileges=",
+            "PrivateTmp=",
+            "ProtectSystem=",
+            "ProtectHome=",
+            "RestrictAddressFamilies=",
+            "RestrictRealtime=",
+            "LockPersonality=",
+            "MemoryDenyWriteExecute=",
+        ] {
+            assert!(
+                !raw.contains(directive),
+                "dosh sessions are user shells; systemd sandbox directive {directive} changes terminal/app behavior"
+            );
+        }
         assert!(
-            raw.contains("RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX AF_NETLINK"),
-            "dosh sessions must allow AF_NETLINK so tools like btop can enumerate network interfaces"
+            !raw.contains("ReadWritePaths="),
+            "remote shells must not be restricted to dosh config/data paths"
         );
     }
 }