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

@@ -38,17 +38,14 @@ path = "src/main.rs"
 [[bin]]
 name = "firewall-service"
 path = "src/bin/firewall-service.rs"
-required-features = ["machine-wide"]
 
 [[bin]]
 name = "firewall-tray"
 path = "src/bin/firewall-tray.rs"
-required-features = ["machine-wide"]
 
 [[bin]]
 name = "firewall-uninstall"
 path = "src/bin/firewall-uninstall.rs"
-required-features = ["machine-wide"]
 
 [[example]]
 name = "proxy-test"
@@ -90,10 +87,6 @@ path = "tests/tpm.rs"
 name = "managers"
 path = "tests/managers.rs"
 
-[features]
-# Builds the machine-wide binaries: the Windows service and tray, and the macOS uninstaller.
-machine-wide = []
-
 [dependencies]
 clap = "4.6.6"
 directories = "6.0.0"
@@ -125,7 +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

@@ -17,7 +17,7 @@ pub struct FirewallConfig {
     /// 0 turns the age check off.
     pub min_age_hours: u64,
     pub denylist: DenylistSource,
-    /// Packages exempt from the age check, by ecosystem: `{"npm": [{"name": "left-pad"}]}`.
+    /// Packages never screened, by ecosystem: `{"npm": [{"name": "left-pad"}]}`.
     pub allow: HashMap<String, Vec<AllowedPackage>>,
     pub telemetry: bool,
     /// Not describable in the file yet, so this is always the built-in table.
@@ -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

@@ -162,7 +162,7 @@ async fn start_screening(status: &ServiceStatusHandle) -> Result<Vec<&'static st
                 resolver: resolver.clone(),
                 service: service.clone(),
             };
-            let upstream = ConsumeErrLayer::trace_as_warning().into_layer(upstream);
+            let upstream = ConsumeErrLayer::trace_as_debug().into_layer(upstream);
             tokio::spawn(listen_on(address, port, &exec)?.serve(upstream));
         }
     }

core/src/policies/filters/mod.rs

@@ -25,18 +25,16 @@ pub trait Filter: Send + Sync {
 }
 
 /// Asks every filter. A `Deny` wins; failing that, the first filter that could not tell.
-/// An allowed package skips only the age check, so malware is never let through.
 pub async fn consult(
     firewall: &Firewall,
     registry: &'static Registry,
     pkg: &Package,
 ) -> Option<(&'static str, Verdict)> {
-    let allowed = allowed(firewall, registry, pkg);
+    if allowed(firewall, registry, pkg) {
+        return None;
+    }
     let mut unsure = None;
     for filter in firewall.filters() {
-        if allowed && filter.name() == "age" {
-            continue;
-        }
         match filter.check(registry, pkg).await {
             Verdict::Allow => continue,
             Verdict::Deny(reason) => return Some((filter.name(), Verdict::Deny(reason))),

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 => {

core/tests/config.rs

@@ -39,14 +39,14 @@ fn a_later_file_wins_and_allow_lists_add_up() {
 }
 
 #[tokio::test]
-async fn an_allowed_version_is_still_checked_for_malware() {
-    // The unreachable denylist shows that it still runs.
+async fn an_allowed_version_skips_the_filters() {
+    // An unreachable denylist would otherwise leave the package unchecked.
     let config = r#"{"allow": {"go": [{"name": "golang.org/x/net", "version": "v0.20.0"}]}, "denylist": {"base": "http://127.0.0.1:1"}}"#;
     let firewall = Firewall::new(serde_json::from_str(config).expect("parses"));
     let (registry, _) = firewall.match_on("/go/golang.org/x/net/@v/list", |r| r.prefix).expect("go");
-    let pkg = Package { name: "golang.org/x/net".into(), version: Some("0.20.0".into()) };
-    let verdict = consult(&firewall, registry, &pkg).await;
-    assert_eq!(verdict.map(|(filter, _)| filter), Some("denylist"));
+    let pkg = |version: &str| Package { name: "golang.org/x/net".into(), version: Some(version.into()) };
+    assert!(consult(&firewall, registry, &pkg("0.20.0")).await.is_none());
+    assert!(consult(&firewall, registry, &pkg("0.21.0")).await.is_some());
 }
 
 #[tokio::test]

dist-workspace.toml

@@ -7,7 +7,6 @@ ci = "github"
 installers = ["shell", "powershell", "homebrew", "msi"]
 # core/wix/main.wxs is edited to install the service.
 allow-dirty = ["msi"]
-features = ["machine-wide"]
 tap = "usestrix/homebrew-tap"
 publish-jobs = ["homebrew", "./publish-crates"]
 targets = ["aarch64-apple-darwin", "x86_64-apple-darwin", "aarch64-unknown-linux-gnu", "x86_64-unknown-linux-gnu", "x86_64-pc-windows-msvc"]

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)")
-                    }
-                }
-            }
-        }
     }
 }

macos/project.yml

@@ -133,7 +133,7 @@ targets:
               arm64|arm64e) triple=aarch64-apple-darwin ;;
               x86_64)       triple=x86_64-apple-darwin ;;
             esac
-            cargo build --bin firewall-uninstall --features machine-wide --target $triple $([ "$CONFIGURATION" = Debug ] || echo --release)
+            cargo build --bin firewall-uninstall --target $triple $([ "$CONFIGURATION" = Debug ] || echo --release)
             bins="$bins target/$triple/$CARGO_PROFILE/firewall-uninstall"
           done
           lipo -create $bins -output "$TARGET_BUILD_DIR/$EXECUTABLE_FOLDER_PATH/firewall-uninstall"