chore: release v0.4.4 on master

A Scheduled Task stores an absolute path. Checking that a task named
"OSTP TUN Helper" exists said nothing about whether its <Command> still points
at the helper we are about to run, and the paths do drift: a dev build
registers target\debug\ostp-tun-helper.exe, an installer registers Program
Files, and moving or reinstalling the app leaves the old path behind.

That failed silently in the worst way. schtasks /Run reports success for
merely ACCEPTING the launch request — a task whose exe no longer exists fails
afterwards, out of band, with nothing returned to us. So launch_as_admin
returned Ok, and the caller then sat in its 60-second connect loop before
reporting "Timeout connecting to helper." On every connect, permanently, with
no way out except deleting the task by hand.

The check now reads the registered <Command> back and compares it to the exe,
re-registering through the existing /F overwrite when they differ: one consent
prompt, once, instead of a permanent silent breakage.

The path is read via /Query /XML rather than /FO LIST /V because the list
format's field labels are localized — "Task To Run" is "Задача для запуска" on
a Russian Windows — while XML tag names are not. schtasks emits UTF-16LE with
a BOM there, which is decoded explicitly, with UTF-8 tolerated as a fallback.
Both paths are canonicalized before comparison so casing, `..` and 8.3 short
names do not read as a mismatch; a path that cannot be canonicalized no longer
exists, which is itself grounds to re-register.

.github/workflows/release.yml

@@ -477,12 +477,19 @@ jobs:
         working-directory: ostp-gui
         run: |
           npm install
+          # TUN mode shells out to this helper, elevated via pkexec. Only the
+          # Windows job used to build it, so the Linux package shipped without
+          # it and TUN could never start.
+          cargo build -p ostp-tun-helper --release --target ${{ matrix.target }} --manifest-path ../Cargo.toml
           npx tauri build --no-bundle --target ${{ matrix.target }}
 
       - name: Package Portable Tarball
         run: |
+          set -euo pipefail
           mkdir ostp-linux-gui-${{ matrix.arch }}
           cp ostp-gui/src-tauri/target/${{ matrix.target }}/release/ostp-gui ostp-linux-gui-${{ matrix.arch }}/
+          # The GUI looks for the helper next to its own executable first.
+          cp target/${{ matrix.target }}/release/ostp-tun-helper ostp-linux-gui-${{ matrix.arch }}/
           tar -czf ostp-linux-gui-${{ matrix.arch }}.tar.gz ostp-linux-gui-${{ matrix.arch }}
 
       - name: Upload to GitHub Release

.release-state.json

@@ -1,6 +1,6 @@
 {
-  "target_version": "0.4.3",
+  "target_version": "0.4.4",
-  "branch": "beta",
+  "branch": "master",
   "alpha_iteration": 0,
-  "beta_iteration": 2
+  "beta_iteration": 0
 }

Cargo.lock

@@ -1386,7 +1386,7 @@ checksum = "c08d65885ee38876c4f86fa503fb49d7b507c2b62552df7c70b2fce627e06381"
 
 [[package]]
 name = "ostp"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "base64",
@@ -1409,7 +1409,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-client"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "base64",
@@ -1440,7 +1440,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-core"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "bytes",
@@ -1474,7 +1474,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-server"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "axum",
@@ -1507,7 +1507,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-tun"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "libc",
@@ -1519,7 +1519,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-tun-helper"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "chrono",

Cargo.toml

@@ -12,7 +12,7 @@ resolver = "2"
 [workspace.package]
 edition = "2021"
 license = "AGPL-3.0"
-version = "0.4.3"
+version = "0.4.4"
 
 [workspace.dependencies]
 anyhow = "1.0"

ostp-client/src/bridge.rs

@@ -23,6 +23,12 @@ use crate::tunnel::{ProxyEvent, ProxyToClientMsg};
 /// candidate address is tried.
 const UOT_CONNECT_TIMEOUT: Duration = Duration::from_secs(4);
 
+/// How long to keep retrying a resume-triggered reconnect before handing the
+/// problem back to the ordinary stall path. That path is what releases the
+/// system proxy, so this is really a bound on how long the machine may be left
+/// with no working internet at all after waking.
+const RESUME_RECONNECT_GIVE_UP: Duration = Duration::from_secs(45);
+
 static SOCKET_PROTECTOR: std::sync::OnceLock<Box<dyn Fn(i32) -> bool + Send + Sync>> = std::sync::OnceLock::new();
 
 pub fn set_socket_protector<F>(f: F)
@@ -147,6 +153,11 @@ pub struct Bridge {
     /// fire at all. Retrying until success removes the dependency on either.
     forced_reconnect_pending: bool,
     last_forced_reconnect_try: Instant,
+    /// Wall-clock start of the current resume-reconnect campaign, used to bound
+    /// it. Wall clock rather than Instant because the monotonic clock does not
+    /// advance across suspend on Windows, so it cannot measure anything that
+    /// begins at wake.
+    forced_reconnect_started: Option<SystemTime>,
 }
 
 impl Bridge {
@@ -185,6 +196,7 @@ impl Bridge {
             last_valid_recv: Instant::now(),
             forced_reconnect_pending: false,
             last_forced_reconnect_try: Instant::now(),
+            forced_reconnect_started: None,
         })
     }
 
@@ -268,9 +280,45 @@ impl Bridge {
                             "Resumed after ~{}s suspend — forcing clean reconnect", wall_gap.as_secs()
                         ))).await;
                         self.forced_reconnect_pending = true;
+                        self.forced_reconnect_started = Some(SystemTime::now());
                         self.last_forced_reconnect_try = Instant::now() - Duration::from_secs(60);
                     }
 
+                    // Give up if resume reconnects keep failing. Retrying forever
+                    // looks harmless but is not: the system proxy stays pointed at
+                    // our local listener the whole time, so the machine has NO
+                    // working internet — not merely no tunnel — while the UI sits
+                    // on "connecting". Handing the retry to the ordinary keepalive
+                    // path restores the proxy through its hard-timeout branch,
+                    // which force=true deliberately skips.
+                    //
+                    // Measured on the wall clock: Instant does not advance across
+                    // suspend on Windows (QPC stops), so a monotonic deadline can
+                    // not bound anything that starts at wake.
+                    if self.forced_reconnect_pending {
+                        let pending_for = self
+                            .forced_reconnect_started
+                            .and_then(|t| t.elapsed().ok())
+                            .unwrap_or_default();
+                        if pending_for > RESUME_RECONNECT_GIVE_UP {
+                            self.forced_reconnect_pending = false;
+                            self.forced_reconnect_started = None;
+                            let _ = tx.send(UiEvent::Log(format!(
+                                "Reconnect after suspend failed for {}s — releasing the system \
+                                 proxy so normal traffic works; will keep retrying in the \
+                                 background",
+                                pending_for.as_secs()
+                            ))).await;
+                            // Make the ordinary stall path fire on the next
+                            // keepalive tick: it is the one that tears the proxy
+                            // back down (or, with kill switch on, deliberately
+                            // keeps blocking).
+                            self.last_valid_recv = Instant::now()
+                                .checked_sub(Duration::from_secs(3600))
+                                .unwrap_or_else(Instant::now);
+                        }
+                    }
+
                     // Keep retrying a resume-triggered reconnect until one lands.
                     // The first attempt fires within half a second of waking, when
                     // the NIC is typically still reassociating, so treating it as
@@ -286,6 +334,7 @@ impl Bridge {
                         // success check rather than "we tried".
                         if self.last_valid_recv.elapsed() < Duration::from_secs(3) {
                             self.forced_reconnect_pending = false;
+                            self.forced_reconnect_started = None;
                             let _ = tx.send(UiEvent::Log("Reconnected after suspend".into())).await;
                         }
                     }

ostp-flutter/pubspec.yaml

@@ -16,7 +16,7 @@ publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
 # In Windows, build-name is used as the major, minor, and patch parts
 # of the product and file versions while build-number is used as the build suffix.
-version: 0.4.3+27
+version: 0.4.4+31
 
 environment:
   sdk: ^3.11.4

ostp-gui/package.json

@@ -1,7 +1,7 @@
 {
   "name": "ostp-gui",
   "private": true,
-  "version": "0.4.3",
+  "version": "0.4.4",
   "type": "module",
   "scripts": {
     "tauri": "tauri",

ostp-gui/src-tauri/Cargo.lock

@@ -2665,7 +2665,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-client"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "base64 0.22.1",
@@ -2696,7 +2696,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-core"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "bytes",
@@ -2713,7 +2713,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-gui"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "json_comments",
@@ -2733,7 +2733,7 @@ dependencies = [
 
 [[package]]
 name = "ostp-tun"
-version = "0.4.3"
+version = "0.4.4"
 dependencies = [
  "anyhow",
  "libc",

ostp-gui/src-tauri/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ostp-gui"
-version = "0.4.3"
+version = "0.4.4"
 description = "OSTP desktop GUI"
 authors = ["ospab"]
 edition = "2021"

ostp-gui/src-tauri/src/lib.rs

@@ -204,19 +204,34 @@ fn get_wintun_install_path() -> String {
     String::new()
 }
 
+/// A `Command` for a console program, with the console window suppressed.
+///
+/// The GUI is a windowed-subsystem binary, so every console child it spawns
+/// pops up a console window for as long as that child runs. With `reg`,
+/// `tasklist` and `schtasks` all being invoked from here, that surfaced as
+/// windows flashing on screen — worst while polling for the scheduled task,
+/// which could spawn twenty of them in a row.
+#[cfg(target_os = "windows")]
+fn quiet_command(program: &str) -> std::process::Command {
+    use std::os::windows::process::CommandExt;
+    const CREATE_NO_WINDOW: u32 = 0x0800_0000;
+    let mut cmd = std::process::Command::new(program);
+    cmd.creation_flags(CREATE_NO_WINDOW);
+    cmd
+}
+
 /// Sets or removes the app from Windows startup (HKCU\...\Run).
 #[tauri::command]
 fn set_autostart(enable: bool) -> Result<(), String> {
     #[cfg(target_os = "windows")]
     {
-        use std::process::Command;
         let key = r"HKCU\Software\Microsoft\Windows\CurrentVersion\Run";
         let app_name = "OSTP";
         if enable {
             let exe = std::env::current_exe()
                 .map_err(|e| format!("Cannot get exe path: {}", e))?;
             let exe_str = format!("\"{}\"", exe.to_string_lossy());
-            let out = Command::new("reg")
+            let out = quiet_command("reg")
                 .args(["add", key, "/v", app_name, "/t", "REG_SZ", "/d", &exe_str, "/f"])
                 .output()
                 .map_err(|e| format!("reg add failed: {}", e))?;
@@ -224,28 +239,71 @@ fn set_autostart(enable: bool) -> Result<(), String> {
                 return Err(String::from_utf8_lossy(&out.stderr).to_string());
             }
         } else {
-            let _ = Command::new("reg")
+            let _ = quiet_command("reg")
                 .args(["delete", key, "/v", app_name, "/f"])
                 .output();
         }
     }
+    #[cfg(target_os = "linux")]
+    {
+        // XDG autostart: desktop environments launch every .desktop file in
+        // ~/.config/autostart on login. This is the portable equivalent of the
+        // HKCU Run key above and needs no elevation.
+        let path = linux_autostart_path().ok_or("Cannot determine the autostart directory")?;
+        if enable {
+            let exe = std::env::current_exe().map_err(|e| format!("Cannot get exe path: {}", e))?;
+            if let Some(dir) = path.parent() {
+                std::fs::create_dir_all(dir)
+                    .map_err(|e| format!("Cannot create {}: {}", dir.display(), e))?;
+            }
+            let entry = format!(
+                "[Desktop Entry]\n\
+                 Type=Application\n\
+                 Name=OSTP\n\
+                 Exec=\"{}\"\n\
+                 Terminal=false\n\
+                 X-GNOME-Autostart-enabled=true\n",
+                exe.display()
+            );
+            std::fs::write(&path, entry)
+                .map_err(|e| format!("Cannot write {}: {}", path.display(), e))?;
+        } else if path.exists() {
+            std::fs::remove_file(&path)
+                .map_err(|e| format!("Cannot remove {}: {}", path.display(), e))?;
+        }
+    }
     Ok(())
 }
 
+/// Path of the XDG autostart entry, honouring XDG_CONFIG_HOME.
+#[cfg(target_os = "linux")]
+fn linux_autostart_path() -> Option<PathBuf> {
+    let base = std::env::var_os("XDG_CONFIG_HOME")
+        .map(PathBuf::from)
+        .filter(|p| !p.as_os_str().is_empty())
+        .or_else(|| std::env::var_os("HOME").map(|h| PathBuf::from(h).join(".config")))?;
+    Some(base.join("autostart").join("ostp.desktop"))
+}
+
 /// Checks if the app is currently in Windows startup.
 #[tauri::command]
 fn get_autostart() -> bool {
     #[cfg(target_os = "windows")]
     {
-        use std::process::Command;
         let key = r"HKCU\Software\Microsoft\Windows\CurrentVersion\Run";
-        let out = Command::new("reg")
+        let out = quiet_command("reg")
             .args(["query", key, "/v", "OSTP"])
             .output();
         if let Ok(o) = out {
             return o.status.success();
         }
     }
+    #[cfg(target_os = "linux")]
+    {
+        if let Some(path) = linux_autostart_path() {
+            return path.exists();
+        }
+    }
     false
 }
 
@@ -254,8 +312,7 @@ fn get_autostart() -> bool {
 fn list_running_processes() -> Vec<String> {
     #[cfg(target_os = "windows")]
     {
-        use std::process::Command;
+        if let Ok(out) = quiet_command("tasklist")
-        if let Ok(out) = Command::new("tasklist")
             .args(["/FO", "CSV", "/NH"])
             .output()
         {
@@ -625,13 +682,18 @@ async fn start_tun_via_helper(
     raw: &ClientConfigRaw,
     app: tauri::AppHandle,
 ) -> Result<bool, String> {
+    // TUN goes through a privileged helper. Elevation is implemented for
+    // Windows (UAC) and Linux (polkit/pkexec); anywhere else launch_as_admin
+    // reports that plainly rather than letting this fail later as a confusing
+    // missing-file error.
     let port = {
         let listener = std::net::TcpListener::bind("127.0.0.1:0").map_err(|e| format!("Bind error: {}", e))?;
         listener.local_addr().unwrap().port()
     };
 
     let auth_token = rand::random::<u64>().to_string();
-    let helper_exe = find_helper_exe().ok_or_else(|| "ostp-tun-helper.exe not found.".to_string())?;
+    let helper_exe = find_helper_exe()
+        .ok_or_else(|| format!("{HELPER_EXE_NAME} not found next to the app or in target/."))?;
     launch_as_admin(&helper_exe, &auth_token, port).map_err(|e| format!("Failed to launch helper: {}", e))?;
     tokio::time::sleep(std::time::Duration::from_millis(1500)).await;
 
@@ -705,11 +767,22 @@ struct HelperPipeState {
     error_msg: Option<String>,
 }
 
+/// Executable name of the TUN helper for the current platform.
+///
+/// The ".exe" suffix was hardcoded, so on Linux every lookup below searched for
+/// a file that cannot exist and the GUI reported the helper as missing on a
+/// platform where it ships without an extension.
+const HELPER_EXE_NAME: &str = if cfg!(windows) {
+    "ostp-tun-helper.exe"
+} else {
+    "ostp-tun-helper"
+};
+
 fn find_helper_exe() -> Option<PathBuf> {
     if let Ok(exe) = std::env::current_exe() {
         if let Some(dir) = exe.parent() {
             // 1. Release/Production adjacent
-            let candidate = dir.join("ostp-tun-helper.exe");
+            let candidate = dir.join(HELPER_EXE_NAME);
             if candidate.exists() { return Some(candidate); }
 
             // 2. Tauri target directory fallback
@@ -717,9 +790,9 @@ fn find_helper_exe() -> Option<PathBuf> {
             let mut parent = dir;
             while let Some(p) = parent.parent() {
                 if p.file_name().map(|n| n == "target").unwrap_or(false) {
-                    let deb = p.join("debug").join("ostp-tun-helper.exe");
+                    let deb = p.join("debug").join(HELPER_EXE_NAME);
                     if deb.exists() { return Some(deb); }
-                    let rel = p.join("release").join("ostp-tun-helper.exe");
+                    let rel = p.join("release").join(HELPER_EXE_NAME);
                     if rel.exists() { return Some(rel); }
                 }
                 parent = p;
@@ -729,13 +802,13 @@ fn find_helper_exe() -> Option<PathBuf> {
     // 3. Current working directory target fallback
     let cwd = std::env::current_dir().unwrap_or_default();
     let candidates = [
-        cwd.join("ostp-tun-helper.exe"),
+        cwd.join(HELPER_EXE_NAME),
-        cwd.join("target").join("debug").join("ostp-tun-helper.exe"),
+        cwd.join("target").join("debug").join(HELPER_EXE_NAME),
-        cwd.join("target").join("release").join("ostp-tun-helper.exe"),
+        cwd.join("target").join("release").join(HELPER_EXE_NAME),
-        cwd.join("..").join("target").join("debug").join("ostp-tun-helper.exe"),
+        cwd.join("..").join("target").join("debug").join(HELPER_EXE_NAME),
-        cwd.join("..").join("target").join("release").join("ostp-tun-helper.exe"),
+        cwd.join("..").join("target").join("release").join(HELPER_EXE_NAME),
-        cwd.join("..").join("..").join("target").join("debug").join("ostp-tun-helper.exe"),
+        cwd.join("..").join("..").join("target").join("debug").join(HELPER_EXE_NAME),
-        cwd.join("..").join("..").join("target").join("release").join("ostp-tun-helper.exe"),
+        cwd.join("..").join("..").join("target").join("release").join(HELPER_EXE_NAME),
     ];
     for path in &candidates {
         if path.exists() { return Some(path.clone()); }
@@ -743,8 +816,272 @@ fn find_helper_exe() -> Option<PathBuf> {
     None
 }
 
+/// Name of the Scheduled Task that runs the helper elevated without a prompt.
+#[cfg(target_os = "windows")]
+const HELPER_TASK_NAME: &str = "OSTP TUN Helper";
+
+/// Fixed path the GUI writes launch parameters to, and the task's command line
+/// reads them from.
+///
+/// A Scheduled Task stores a FIXED command line, so the per-launch port and
+/// token cannot travel as arguments. The file lives under the user's own
+/// LOCALAPPDATA: the helper runs elevated but as the SAME user, so this keeps
+/// the token inside the trust boundary it already had — no other user can read
+/// it, which would not be true of a shared location.
+#[cfg(target_os = "windows")]
+fn helper_args_file() -> PathBuf {
+    let base = std::env::var_os("LOCALAPPDATA")
+        .map(PathBuf::from)
+        .unwrap_or_else(std::env::temp_dir);
+    base.join("OSTP").join("helper-args.json")
+}
+
+/// Minimal XML text escaping for the values interpolated into the task
+/// definition. Paths and usernames are attacker-irrelevant here but can easily
+/// contain `&`, which would otherwise produce invalid XML and a confusing
+/// schtasks parse failure.
+#[cfg(target_os = "windows")]
+fn xml_escape(s: &str) -> String {
+    s.replace('&', "&amp;")
+        .replace('<', "&lt;")
+        .replace('>', "&gt;")
+        .replace('"', "&quot;")
+        .replace('\'', "&apos;")
+}
+
+/// Reverse of [`xml_escape`]. `&amp;` must be undone last or `&amp;lt;` would
+/// come back as `<`.
+#[cfg(target_os = "windows")]
+fn xml_unescape(s: &str) -> String {
+    s.replace("&quot;", "\"")
+        .replace("&apos;", "'")
+        .replace("&lt;", "<")
+        .replace("&gt;", ">")
+        .replace("&amp;", "&")
+}
+
+/// The exe path currently baked into the registered task, if any.
+///
+/// Queried as XML rather than `/FO LIST /V`: the list format's field labels are
+/// localized (on a Russian Windows "Task To Run" is "Задача для запуска"),
+/// whereas XML tag names are fixed. schtasks writes UTF-16LE with a BOM here,
+/// but tolerate UTF-8 in case that ever changes.
+#[cfg(target_os = "windows")]
+fn helper_task_command() -> Option<String> {
+    let out = quiet_command("schtasks")
+        .args(["/Query", "/TN", HELPER_TASK_NAME, "/XML"])
+        .output()
+        .ok()?;
+    if !out.status.success() {
+        return None;
+    }
+
+    let text = if out.stdout.starts_with(&[0xFF, 0xFE]) {
+        let units: Vec<u16> = out.stdout[2..]
+            .chunks_exact(2)
+            .map(|c| u16::from_le_bytes([c[0], c[1]]))
+            .collect();
+        String::from_utf16_lossy(&units)
+    } else {
+        String::from_utf8_lossy(&out.stdout).into_owned()
+    };
+
+    let start = text.find("<Command>")? + "<Command>".len();
+    let end = text[start..].find("</Command>")? + start;
+    Some(xml_unescape(text[start..end].trim()))
+}
+
+/// Whether a task is registered AND still points at the exe we are about to run.
+///
+/// The path matters as much as the name. A task registered by a dev build (or
+/// by an install that has since moved) keeps its original `<Command>`, and
+/// `schtasks /Run` reports success merely for *accepting* the request — a task
+/// whose exe no longer exists fails asynchronously and silently. Trusting the
+/// name alone therefore bought a 60-second "Timeout connecting to helper" on
+/// every single connect, permanently, until the task was deleted by hand.
+/// Re-registering costs one consent prompt and fixes it for good.
+#[cfg(target_os = "windows")]
+fn helper_task_matches(exe: &std::path::Path) -> bool {
+    let Some(registered) = helper_task_command() else {
+        return false;
+    };
+    let registered = registered.trim().trim_matches('"');
+
+    // Canonicalize both sides when possible so `..`, short 8.3 names and
+    // casing differences do not read as a mismatch. A missing file cannot be
+    // canonicalized — which is itself a mismatch worth re-registering over.
+    match (
+        std::fs::canonicalize(registered),
+        std::fs::canonicalize(exe),
+    ) {
+        (Ok(a), Ok(b)) => a == b,
+        _ => registered.eq_ignore_ascii_case(&exe.display().to_string()),
+    }
+}
+
+/// Register the Scheduled Task. This is the ONLY step that needs elevation, and
+/// it happens once per machine; every later tunnel start reuses the task.
+///
+/// RunLevel=HIGHEST makes the task run elevated, and because a task launch is
+/// not an elevation request, Windows shows no consent dialog for it.
+#[cfg(target_os = "windows")]
+fn install_helper_task(exe: &std::path::Path) -> anyhow::Result<()> {
+    let args_file = helper_args_file();
+    if let Some(dir) = args_file.parent() {
+        std::fs::create_dir_all(dir)?;
+    }
+
+    // Register from an XML definition rather than /TR. The command line would
+    // otherwise need the exe path and the args path quoted INSIDE an already
+    // quoted /TR value, escaped again through ShellExecuteW — a notoriously
+    // brittle chain when either path contains a space, which both of these do
+    // by default (Program Files, and usernames with spaces). XML also lets the
+    // battery and time-limit settings below be stated explicitly.
+    let user = format!(
+        "{}\\{}",
+        std::env::var("USERDOMAIN").unwrap_or_else(|_| "%COMPUTERNAME%".into()),
+        std::env::var("USERNAME").unwrap_or_default()
+    );
+    let xml = format!(
+        r#"<?xml version="1.0" encoding="UTF-16"?>
+<Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
+  <RegistrationInfo>
+    <Description>Runs the OSTP TUN helper elevated so enabling the tunnel does not prompt for consent every time.</Description>
+  </RegistrationInfo>
+  <Principals>
+    <Principal id="Author">
+      <UserId>{user}</UserId>
+      <LogonType>InteractiveToken</LogonType>
+      <RunLevel>HighestAvailable</RunLevel>
+    </Principal>
+  </Principals>
+  <Settings>
+    <MultipleInstancesPolicy>Parallel</MultipleInstancesPolicy>
+    <DisallowStartIfOnBatteries>false</DisallowStartIfOnBatteries>
+    <StopIfGoingOnBatteries>false</StopIfGoingOnBatteries>
+    <StartWhenAvailable>false</StartWhenAvailable>
+    <RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable>
+    <ExecutionTimeLimit>PT0S</ExecutionTimeLimit>
+    <Enabled>true</Enabled>
+    <Hidden>false</Hidden>
+    <AllowHardTerminate>true</AllowHardTerminate>
+  </Settings>
+  <Actions Context="Author">
+    <Exec>
+      <Command>{exe}</Command>
+      <Arguments>--args-file "{args}"</Arguments>
+    </Exec>
+  </Actions>
+</Task>
+"#,
+        user = xml_escape(&user),
+        exe = xml_escape(&exe.display().to_string()),
+        args = xml_escape(&args_file.display().to_string()),
+    );
+
+    // schtasks /Create /XML expects UTF-16LE with a BOM.
+    let xml_path = std::env::temp_dir().join(format!("ostp_task_{}.xml", rand::random::<u32>()));
+    let mut utf16: Vec<u8> = vec![0xFF, 0xFE];
+    for unit in xml.encode_utf16() {
+        utf16.extend_from_slice(&unit.to_le_bytes());
+    }
+    std::fs::write(&xml_path, &utf16)?;
+
+    // Registering a HighestAvailable task is itself privileged: this is the one
+    // prompt, and it happens once per machine.
+    //
+    // Elevate through PowerShell's Start-Process -Wait rather than
+    // ShellExecuteW. ShellExecuteW returns as soon as the elevated process is
+    // LAUNCHED, so the XML below was being deleted while schtasks was still
+    // starting up — registration then failed, leaving the user with a consent
+    // prompt that accomplished nothing, followed by a second prompt from the
+    // fallback path. -Wait makes the deletion safe and lets the exit code be
+    // checked instead of guessed at by polling.
+    //
+    // ArgumentList takes an array, so the task name and XML path never need
+    // quoting or escaping through a command line, only PowerShell's own
+    // single-quote doubling.
+    let ps = format!(
+        "$p = Start-Process -FilePath 'schtasks.exe' -Verb RunAs -Wait -PassThru \
+         -WindowStyle Hidden -ArgumentList @('/Create','/TN','{}','/XML','{}','/F'); \
+         exit $p.ExitCode",
+        ps_quote(HELPER_TASK_NAME),
+        ps_quote(&xml_path.display().to_string()),
+    );
+
+    let status = quiet_command("powershell")
+        .args(["-NoProfile", "-NonInteractive", "-WindowStyle", "Hidden", "-Command", &ps])
+        .status();
+
+    // schtasks has exited by now, so this is safe.
+    let _ = std::fs::remove_file(&xml_path);
+
+    match status {
+        Ok(s) if s.success() => {}
+        Ok(s) => anyhow::bail!(
+            "registering the scheduled task failed (exit code {:?}). A declined consent prompt \
+             reports 1223.",
+            s.code()
+        ),
+        Err(e) => anyhow::bail!("could not run powershell to register the task: {e}"),
+    }
+
+    if helper_task_matches(exe) {
+        Ok(())
+    } else {
+        anyhow::bail!("schtasks reported success but the task does not point at {}", exe.display())
+    }
+}
+
+/// Escape a value for embedding in a PowerShell single-quoted string.
+#[cfg(target_os = "windows")]
+fn ps_quote(s: &str) -> String {
+    s.replace('\'', "''")
+}
+
 #[cfg(target_os = "windows")]
 fn launch_as_admin(exe: &std::path::PathBuf, token: &str, port: u16) -> anyhow::Result<()> {
+    // Preferred path: hand the parameters over in a file and trigger the
+    // pre-registered task, which runs elevated with no prompt. Falls back to a
+    // direct elevated launch when the task is absent (first ever run, or the
+    // user removed it) — and that first run is also where the task gets created,
+    // so the prompt appears once rather than on every connect.
+    let args_file = helper_args_file();
+    if let Some(dir) = args_file.parent() {
+        let _ = std::fs::create_dir_all(dir);
+    }
+    let payload = serde_json::json!({ "port": port, "token": token });
+    let wrote_args = std::fs::write(&args_file, payload.to_string()).is_ok();
+
+    if wrote_args {
+        if !helper_task_matches(exe) {
+            if let Err(e) = install_helper_task(exe) {
+                eprintln!("[OSTP] could not register the helper task ({e}); falling back to a direct elevated launch");
+            }
+        }
+        if helper_task_matches(exe) {
+            let run = quiet_command("schtasks")
+                .args(["/Run", "/TN", HELPER_TASK_NAME])
+                .output();
+            match run {
+                Ok(o) if o.status.success() => return Ok(()),
+                Ok(o) => eprintln!(
+                    "[OSTP] schtasks /Run failed: {}",
+                    String::from_utf8_lossy(&o.stderr).trim()
+                ),
+                Err(e) => eprintln!("[OSTP] schtasks /Run could not start: {e}"),
+            }
+        }
+        // Falling through: remove the file so a stale token is not left behind.
+        let _ = std::fs::remove_file(&args_file);
+    }
+
+    launch_as_admin_direct(exe, token, port)
+}
+
+/// The original one-prompt-per-launch path, kept as the fallback.
+#[cfg(target_os = "windows")]
+fn launch_as_admin_direct(exe: &std::path::PathBuf, token: &str, port: u16) -> anyhow::Result<()> {
     use std::ffi::OsStr;
     use std::os::windows::ffi::OsStrExt;
     use std::ptr::null_mut;
@@ -797,8 +1134,50 @@ fn launch_as_admin(exe: &std::path::PathBuf, token: &str, port: u16) -> anyhow::
     Ok(())
 }
 
-#[cfg(not(target_os = "windows"))]
+#[cfg(target_os = "linux")]
-fn launch_as_admin(_exe: &PathBuf, _token: &str, _port: u16) -> Result<()> { anyhow::bail!("Windows only."); }
+fn launch_as_admin(exe: &PathBuf, token: &str, port: u16) -> Result<()> {
+    use std::os::unix::fs::PermissionsExt;
+    use std::process::Command;
+
+    // Same shape as the Windows path: the token goes through a file rather than
+    // argv, so it never shows up in the process list.
+    let token_file = std::env::temp_dir().join(format!("ostp_auth_{}.tmp", rand::random::<u32>()));
+    std::fs::write(&token_file, token)?;
+    // Unlike Windows, /tmp is world-readable here, and this token authenticates
+    // control of the privileged tunnel helper — restrict it to the owner.
+    let _ = std::fs::set_permissions(&token_file, std::fs::Permissions::from_mode(0o600));
+
+    // pkexec is polkit's front-end: in a desktop session it raises a graphical
+    // authentication dialog. sudo is not an option from a GUI process, which has
+    // no terminal to prompt on.
+    match Command::new("pkexec")
+        .arg(exe)
+        .arg("--port")
+        .arg(port.to_string())
+        .arg("--token-file")
+        .arg(&token_file)
+        .spawn()
+    {
+        Ok(_) => Ok(()),
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => {
+            let _ = std::fs::remove_file(&token_file);
+            anyhow::bail!(
+                "pkexec was not found, so the TUN helper cannot be granted the privileges it \
+                 needs. Install polkit (package \"policykit-1\" on Debian/Ubuntu, \"polkit\" on \
+                 Fedora/Arch), or use proxy mode, which needs no elevation."
+            )
+        }
+        Err(e) => {
+            let _ = std::fs::remove_file(&token_file);
+            Err(e.into())
+        }
+    }
+}
+
+#[cfg(not(any(target_os = "windows", target_os = "linux")))]
+fn launch_as_admin(_exe: &PathBuf, _token: &str, _port: u16) -> Result<()> {
+    anyhow::bail!("TUN mode needs a privileged helper, which is implemented on Windows and Linux only. Use proxy mode on this platform.");
+}
 
 #[cfg(target_os = "windows")]
 fn show_error_dialog(msg: &str) {

ostp-gui/src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "ostp-gui",
-  "version": "0.4.3",
+  "version": "0.4.4",
   "identifier": "com.ospab.ostp",
   "build": {
     "frontendDist": "../src"
@@ -11,9 +11,11 @@
     "windows": [
       {
         "title": "OSTP",
-        "width": 360,
+        "width": 400,
-        "height": 680,
+        "height": 720,
-        "resizable": false
+        "minWidth": 360,
+        "minHeight": 560,
+        "resizable": true
       }
     ],
     "security": {

ostp-gui/src/main.js

@@ -660,6 +660,13 @@ function loadSettingsIntoForm() {
   updateClientVisibility();
 }
 
+// Last values actually pushed to the OS / backend, so repeated saves that did
+// not change them stay free. Undefined until the first save, which is correct:
+// the first one should apply.
+let lastAppliedAutostart;
+let lastAppliedTunnelConfig;
+let hotReloadTimer;
+
 function collectAndSaveSettings() {
   const s = {
     tun:          inTun.checked,
@@ -686,19 +693,41 @@ function collectAndSaveSettings() {
     fragChunk:    parseInt(inFragChunk.value) || 2,
     fragSleep:    !isNaN(parseInt(inFragSleep.value)) ? parseInt(inFragSleep.value) : 2,
   };
+  // Cheap and local: safe to run on every debounced keystroke.
   saveClientSettings(s);
   updateClientVisibility();
 
-  // Set autostart
+  // Everything below talks to the OS or restarts the tunnel. Running it per
-  invoke('set_autostart', { enable: s.launchStartup }).catch(() => {});
+  // keystroke is what made typing in the exclusion fields lag by seconds: the
+  // 400ms debounce fires during natural pauses in typing, and each firing hit
+  // the Windows registry and then tore down and rebuilt the tunnel.
 
-  // Hot-reload exclusions if connected
+  // Only touch autostart when it actually changed — this is a registry write.
+  if (s.launchStartup !== lastAppliedAutostart) {
+    lastAppliedAutostart = s.launchStartup;
+    invoke('set_autostart', { enable: s.launchStartup }).catch(() => {});
+  }
+
+  // Hot-reload the tunnel only when something it actually reads has changed,
+  // and on a much longer debounce: a reload is disruptive, so it should land
+  // once the user has stopped editing rather than between keystrokes.
   if (appState === 'connected') {
-    const cfg = buildConfig();
+    const tunnelRelevant = JSON.stringify([
-    if (cfg) {
+      s.tun, s.killSwitch, s.mux, s.muxSessions, s.mtu, s.dns, s.socks,
-      invoke('save_config', { jsonContent: JSON.stringify(cfg, null, 2) })
+      s.exDomains, s.exIps, s.exProcs, s.junkEnabled, s.junkPcMin, s.junkPcMax,
-        .then(() => invoke('reload_tunnel'))
+      s.junkPsMin, s.junkPsMax, s.tcpFrag, s.fragChunk, s.fragSleep,
-        .catch(() => {});
+    ]);
+    if (tunnelRelevant !== lastAppliedTunnelConfig) {
+      clearTimeout(hotReloadTimer);
+      hotReloadTimer = setTimeout(() => {
+        lastAppliedTunnelConfig = tunnelRelevant;
+        const cfg = buildConfig();
+        if (cfg) {
+          invoke('save_config', { jsonContent: JSON.stringify(cfg, null, 2) })
+            .then(() => invoke('reload_tunnel'))
+            .catch(() => {});
+        }
+      }, 1500);
     }
   }
 }

ostp-gui/src/styles.css

@@ -99,6 +99,13 @@ a { text-decoration: none; }
 .app-root {
   position: relative;
   width: 100%;
+  /* The window is resizable so users on desktops where the toolkit does not
+     apply our DPI scaling (WebKitGTK on HiDPI Linux renders the configured
+     size as raw pixels, giving a postage-stamp window) can size it themselves.
+     Capping and centring the column keeps the intended narrow layout instead of
+     stretching controls across a wide window. */
+  max-width: 460px;
+  margin: 0 auto;
   height: 100%;
   display: flex;
   flex-direction: column;

ostp-tun-helper/build.rs

@@ -4,6 +4,21 @@
 // or launched via ShellExecuteW("runas").
 
 fn main() {
+    // Key off the TARGET, not the host. In a build script `cfg(windows)`
+    // describes the machine doing the building, so cross-compiling the helper
+    // from Windows to Linux took this branch and failed with "Can only compile
+    // resource file when target_env is gnu or msvc". CARGO_CFG_TARGET_OS is the
+    // target being built for, which is what actually decides whether a Windows
+    // manifest belongs in the binary.
+    let target_os = std::env::var("CARGO_CFG_TARGET_OS").unwrap_or_default();
+    if target_os != "windows" {
+        return;
+    }
+    // Second gate, on the HOST: winres is declared under
+    // [target.'cfg(windows)'.build-dependencies], and build-dependencies are
+    // resolved against the host triple, so the crate simply does not exist when
+    // building on Linux. Referencing it unconditionally would fail to compile
+    // there even though the target check above already passed.
     #[cfg(windows)]
     {
         let mut res = winres::WindowsResource::new();

ostp-tun-helper/src/main.rs

@@ -24,6 +24,14 @@ fn log_to_file(msg: &str) {
 
 
 
+/// Launch parameters handed over in a file rather than on the command line.
+/// See the `--args-file` handling in `main` for why.
+#[derive(Deserialize)]
+struct HelperArgs {
+    port: u16,
+    token: String,
+}
+
 #[derive(Deserialize)]
 #[serde(tag = "cmd", rename_all = "lowercase")]
 enum GuiCmd {
@@ -76,6 +84,28 @@ async fn main() -> Result<()> {
                 let _ = std::fs::remove_file(path); // securely delete after reading
             }
         }
+        // Both port and token from one file. A Scheduled Task stores a FIXED
+        // command line, so anything that varies per launch cannot be passed as
+        // an argument — the GUI writes this file immediately before triggering
+        // the task instead. That indirection is what lets the task be created
+        // once (a single UAC prompt) and reused for every later connect without
+        // prompting again.
+        if args[i] == "--args-file" && i + 1 < args.len() {
+            let path = &args[i + 1];
+            match std::fs::read_to_string(path) {
+                Ok(content) => {
+                    let _ = std::fs::remove_file(path); // single use
+                    match serde_json::from_str::<HelperArgs>(&content) {
+                        Ok(parsed) => {
+                            port = parsed.port;
+                            expected_token = parsed.token;
+                        }
+                        Err(e) => log_to_file(&format!("Failed to parse --args-file: {e}")),
+                    }
+                }
+                Err(e) => log_to_file(&format!("Failed to read --args-file {path}: {e}")),
+            }
+        }
     }
 
     log_to_file("Helper started (TCP mode)");