Show a popup when pausing or resuming screening fails

The service now answers Pause and Continue only after rewriting the hosts
file, returning the write's error so the tray's ControlService call fails
and shows it. The tray's popup includes the error's source, which
windows-service's own message hides.

core/Cargo.toml

@@ -118,7 +118,7 @@ schannel = "0.1.29"
 tokio = { version = "1.53.1", features = ["net"] }
 tracing-appender = "0.2.5"
 tray-icon = { version = "0.26.1", default-features = false }
-windows = { version = "0.62", features = ["Win32_Foundation", "Win32_Security", "Win32_Security_Authorization", "Win32_Security_Cryptography", "Win32_System_Com", "Win32_System_Console", "Win32_System_Environment", "Win32_System_JobObjects", "Win32_System_Threading", "Win32_UI_Shell", "Win32_UI_WindowsAndMessaging"] }
+windows = { version = "0.62", features = ["Win32_Foundation", "Win32_Security", "Win32_Security_Authorization", "Win32_Security_Cryptography", "Win32_System_Com", "Win32_System_Environment", "Win32_System_Threading", "Win32_UI_Shell", "Win32_UI_WindowsAndMessaging"] }
 windows-registry = "0.6.1"
 windows-service = "0.8.0"
 

core/src/aliasing/mod.rs

@@ -1,7 +1,5 @@
 pub mod forward;
 pub mod managers;
-#[cfg(windows)]
-mod windows;
 
 pub use forward::spawn;
 pub use managers::*;
@@ -36,8 +34,7 @@ impl Invocation {
 
 pub fn run(port: u16, invocation: &Invocation, dir: Option<&Path>) -> std::io::Result<i32> {
     let proxy = crate::local_url(port, "");
-    let program = resolve(&invocation.program)?;
-    let mut command = Command::new(&program);
+    let mut command = Command::new(resolve(&invocation.program)?);
     command.args(invocation.arguments(&proxy));
     if let Some(dir) = dir {
         command.current_dir(dir);
@@ -45,12 +42,7 @@ pub fn run(port: u16, invocation: &Invocation, dir: Option<&Path>) -> std::io::R
     for (key, value) in managers::variables(&proxy) {
         command.env(key, value);
     }
-    #[cfg(windows)]
-    windows::prepare();
-    let status = command.status();
-    #[cfg(windows)]
-    let status = status.map_err(|error| windows::explain(error, &program));
-    Ok(status?.code().unwrap_or(1))
+    Ok(command.status()?.code().unwrap_or(1))
 }
 
 // Command::new only finds .exe on Windows; npm, pnpm and gem are .cmd shims found via PATHEXT.

core/src/aliasing/windows.rs

@@ -1,64 +0,0 @@
-use std::io::{Error, ErrorKind};
-use std::path::Path;
-use std::sync::Once;
-use tracing::debug;
-use windows::core::{BOOL, PCWSTR};
-use windows::Win32::System::Console::{SetConsoleCtrlHandler, CTRL_BREAK_EVENT, CTRL_C_EVENT};
-use windows::Win32::System::JobObjects::{
-    AssignProcessToJobObject, CreateJobObjectW, JobObjectExtendedLimitInformation,
-    SetInformationJobObject, JOBOBJECT_EXTENDED_LIMIT_INFORMATION,
-    JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE,
-};
-use windows::Win32::System::Threading::GetCurrentProcess;
-
-/// Called before spawning, so the manager behaves as it would run from the shell directly.
-/// Once per process: a caller may run several managers.
-pub fn prepare() {
-    static PREPARED: Once = Once::new();
-    PREPARED.call_once(|| {
-        // The console sends Ctrl+C to the manager too. Exiting first would hand the prompt back
-        // while a .cmd shim still asks "Terminate batch job (Y/N)?", so wait for its exit instead.
-        // A handler, unlike ignoring the signal outright, is not inherited by the manager.
-        let _ = unsafe { SetConsoleCtrlHandler(Some(ignore_interrupt), true) };
-        if let Err(error) = kill_children_on_exit() {
-            debug!(%error, "the manager may outlive the firewall");
-        }
-    });
-}
-
-unsafe extern "system" fn ignore_interrupt(event: u32) -> BOOL {
-    (event == CTRL_C_EVENT || event == CTRL_BREAK_EVENT).into()
-}
-
-/// Joins a job that kills what is left in it once the firewall exits, even if killed itself.
-/// The manager inherits the job when spawned, as do its own children.
-fn kill_children_on_exit() -> windows::core::Result<()> {
-    let mut limits = JOBOBJECT_EXTENDED_LIMIT_INFORMATION::default();
-    limits.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE;
-    // Never closed: the handle closing as the firewall exits is what kills the rest.
-    let job = unsafe { CreateJobObjectW(None, PCWSTR::null())? };
-    unsafe {
-        SetInformationJobObject(
-            job,
-            JobObjectExtendedLimitInformation,
-            (&raw const limits).cast(),
-            size_of_val(&limits) as u32,
-        )?
-    };
-    unsafe { AssignProcessToJobObject(job, GetCurrentProcess()) }
-}
-
-/// Rust refuses to pass a line break to a batch file, where it would cut the command short.
-pub fn explain(error: Error, program: &Path) -> Error {
-    let batch = program
-        .extension()
-        .is_some_and(|ext| ext.eq_ignore_ascii_case("cmd") || ext.eq_ignore_ascii_case("bat"));
-    if !batch || error.kind() != ErrorKind::InvalidInput {
-        return error;
-    }
-    let name = program.file_name().unwrap_or(program.as_os_str()).to_string_lossy();
-    Error::new(
-        ErrorKind::InvalidInput,
-        format!("{name} is a batch file, which cannot be passed an argument with a line break"),
-    )
-}

core/src/blocks.rs

@@ -1,36 +0,0 @@
-use crate::policies::Package;
-use serde::Serialize;
-use std::sync::Mutex;
-
-/// Bounded, so blocks pile up harmlessly while nothing collects them.
-const KEPT: usize = 50;
-
-static RECENT: Mutex<Vec<BlockedPackage>> = Mutex::new(Vec::new());
-
-#[derive(Serialize)]
-pub struct BlockedPackage {
-    pub eco: &'static str,
-    pub name: String,
-    pub version: Option<String>,
-    pub filter: &'static str,
-    pub reason: String,
-}
-
-pub fn record(eco: &'static str, pkg: &Package, filter: &'static str, reason: &str) {
-    let mut recent = RECENT.lock().unwrap_or_else(|e| e.into_inner());
-    if recent.len() == KEPT {
-        recent.remove(0);
-    }
-    recent.push(BlockedPackage {
-        eco,
-        name: pkg.name.clone(),
-        version: pkg.version.clone(),
-        filter,
-        reason: reason.to_owned(),
-    });
-}
-
-/// Hands each block over once.
-pub fn take() -> Vec<BlockedPackage> {
-    std::mem::take(&mut *RECENT.lock().unwrap_or_else(|e| e.into_inner()))
-}

core/src/config/mod.rs

@@ -48,7 +48,7 @@ impl Default for FirewallConfig {
         FirewallConfig {
             port: DEFAULT_PORT,
             fail_open: true,
-            min_age_hours: 24,
+            min_age_hours: 0,
             denylist: DenylistSource::default(),
             allow: HashMap::new(),
             telemetry: true,

core/src/lib.rs

@@ -1,5 +1,4 @@
 pub mod aliasing;
-pub mod blocks;
 pub mod config;
 pub mod firewall;
 pub mod http;

core/src/os/macos/mod.rs

@@ -5,7 +5,7 @@ mod uninstall;
 pub use uninstall::uninstall;
 
 use crate::config::FirewallConfig;
-use crate::{blocks, mitm, telemetry};
+use crate::{mitm, telemetry};
 use crate::Firewall;
 use rama::bytes::Bytes;
 use rama::error::BoxError;
@@ -58,7 +58,6 @@ impl TransparentProxyHandler for Handler {
         let message = String::from_utf8_lossy(&message).into_owned();
         Some(Bytes::from(match message.as_str() {
             "ca" => self.ca.pem.clone(),
-            "blocks" => serde_json::to_string(&blocks::take()).expect("blocks serialize"),
             other => format!("error: unknown message {other}"),
         }))
     }

core/src/os/windows/service.rs

@@ -26,6 +26,7 @@ use std::net::{IpAddr, Ipv4Addr};
 use std::sync::Arc;
 use std::time::Duration;
 use tracing_appender::rolling::{RollingFileAppender, Rotation};
+use windows::Win32::Foundation::ERROR_GEN_FAILURE;
 use windows_service::service::*;
 use windows_service::service_control_handler::{
     self, ServiceControlHandlerResult, ServiceStatusHandle,
@@ -73,8 +74,12 @@ fn run_until_stopped() -> Result<(), BoxError> {
         | ServiceControl::Shutdown
         | ServiceControl::Pause
         | ServiceControl::Continue => {
-            let _ = control_sender.send(control);
-            ServiceControlHandlerResult::NoError
+            // Answered once handled, so a failed pause fails the caller's ControlService.
+            let (reply, handled) = tokio::sync::oneshot::channel();
+            let _ = control_sender.send((control, reply));
+            handled
+                .blocking_recv()
+                .unwrap_or(ServiceControlHandlerResult::NoError)
         }
         ServiceControl::Interrogate => ServiceControlHandlerResult::NoError,
         _ => ServiceControlHandlerResult::NotImplemented,
@@ -89,16 +94,26 @@ fn run_until_stopped() -> Result<(), BoxError> {
             }
         };
         // Only pausing removes our hosts entries; a stop or crash keeps them, failing closed.
-        while let Some(control) = control_receiver.recv().await {
+        while let Some((control, reply)) = control_receiver.recv().await {
             let (hosts, state) = match control {
                 ServiceControl::Pause => (&[][..], ServiceState::Paused),
                 ServiceControl::Continue => (&hosts[..], ServiceState::Running),
                 _ => break,
             };
-            match write_hosts_entries(hosts) {
-                Ok(()) => set_status(&status, state, false)?,
-                Err(error) => tracing::error!(%error, "could not rewrite the hosts file"),
-            }
+            let result = match write_hosts_entries(hosts) {
+                Ok(()) => {
+                    set_status(&status, state, false)?;
+                    ServiceControlHandlerResult::NoError
+                }
+                Err(error) => {
+                    tracing::error!(%error, "could not rewrite the hosts file");
+                    let code = error
+                        .raw_os_error()
+                        .map_or(ERROR_GEN_FAILURE.0, |code| code as u32);
+                    ServiceControlHandlerResult::Other(code)
+                }
+            };
+            let _ = reply.send(result);
         }
         Ok::<_, BoxError>(())
     });

core/src/os/windows/tray.rs

@@ -144,7 +144,11 @@ impl Tray {
 }
 
 fn show_error(error: BoxError) {
-    let text = HSTRING::from(error.to_string());
+    let text = match error.source() {
+        Some(source) => format!("{error}: {source}"),
+        None => error.to_string(),
+    };
+    let text = HSTRING::from(text);
     unsafe { MessageBoxW(None, &text, w!("Strix Firewall"), MB_ICONERROR) };
 }
 

core/src/policies/mod.rs

@@ -69,8 +69,7 @@ pub async fn screen(url: &str, firewall: &Firewall) -> Option<String> {
     };
     info!(eco = registry.eco, pkg = %pkg.label(), %url, "screening");
     match consult(firewall, registry, &pkg).await {
-        Some((filter, Verdict::Deny(reason))) => {
-            crate::blocks::record(registry.eco, &pkg, filter, &reason);
+        Some((_, Verdict::Deny(reason))) => {
             Some(format!("{} {reason}", pkg.label()))
         }
         Some((filter, Verdict::Unknown(e))) if !firewall.config.fail_open => {

macos/App/BlockAlerts.swift

@@ -1,32 +0,0 @@
-import AppKit
-
-struct BlockedPackage: Codable, Hashable, Identifiable {
-    let eco: String
-    let name: String
-    let version: String?
-    let filter: String
-    let reason: String
-
-    var id: String { "\(eco)/\(name)@\(version ?? "")" }
-    var label: String { version.map { "\(name) \($0)" } ?? name }
-    /// The denylist and OSV only flag packages known to be malicious; the age check only holds back new ones.
-    var malicious: Bool { filter != "age" }
-}
-
-@MainActor
-enum BlockAlert {
-    static func show(_ package: BlockedPackage) {
-        let alert = NSAlert()
-        alert.addButton(withTitle: "OK")
-        if package.malicious {
-            alert.alertStyle = .critical
-            alert.messageText = "Blocked a malicious package"
-            alert.informativeText = "\(package.label) (\(package.eco)) \(package.reason). Do not install it."
-        } else {
-            alert.messageText = "Held back a new package"
-            alert.informativeText = "\(package.label) (\(package.eco)) \(package.reason)."
-        }
-        NSApp.activate(ignoringOtherApps: true)
-        alert.runModal()
-    }
-}

macos/App/FirewallModel.swift

@@ -51,7 +51,6 @@ final class FirewallModel: NSObject, ObservableObject {
     @Published private(set) var completed = false
     @Published private(set) var removed = false
     @Published private(set) var screening = false
-    @Published private(set) var blocked: [BlockedPackage] = []
 
     private let logger = Logger(subsystem: FirewallIDs.appBundleID, category: "installer")
     private var pendingRequest: (request: OSSystemExtensionRequest, continuation: CheckedContinuation<Void, Error>)?
@@ -73,7 +72,6 @@ final class FirewallModel: NSObject, ObservableObject {
             await refresh()
             if CommandLine.arguments.contains("--install") { await install() }
         }
-        Task { await watchBlocks() }
     }
 
     // MARK: - Flows
@@ -201,21 +199,6 @@ final class FirewallModel: NSObject, ObservableObject {
         if let url = URL(string: pane) { NSWorkspace.shared.open(url) }
     }
 
-    /// The extension cannot message the app, so the app asks it for blocks.
-    private func watchBlocks() async {
-        while true {
-            if screening, let reply = try? await providerMessage("blocks"),
-               let packages = try? JSONDecoder().decode([BlockedPackage].self, from: Data(reply.utf8)) {
-                for package in packages where !blocked.contains(package) {
-                    blocked.append(package)
-                    BlockAlert.show(package)
-                }
-                blocked = Array(blocked.suffix(10))
-            }
-            try? await Task.sleep(nanoseconds: 2_000_000_000)
-        }
-    }
-
     private func stage(_ step: ReferenceWritableKeyPath<FirewallModel, StepStatus>,
                        running: String,
                        work: @MainActor () async throws -> String) async -> Bool {

macos/App/MenuBarView.swift

@@ -22,20 +22,5 @@ struct MenuBarView: View {
             Task { await model.restart() }
         }
         .disabled(model.busy)
-
-        if !model.blocked.isEmpty {
-            Divider()
-            ForEach(model.blocked) { package in
-                if !package.malicious {
-                    Menu("Held back \(package.label) (\(package.eco))") {
-                        Text(package.reason)
-                    }
-                } else {
-                    Menu("Blocked \(package.label) (\(package.eco))") {
-                        Text("Malicious: \(package.reason)")
-                    }
-                }
-            }
-        }
     }
 }