Warn when npm or uv leaves http:// registry URLs in its lockfile

Co-authored-by: Ian Graham Martinez <[email protected]>

core/Cargo.toml

@@ -90,6 +90,10 @@ path = "tests/tpm.rs"
 name = "managers"
 path = "tests/managers.rs"
 
+[[test]]
+name = "blocks"
+path = "tests/blocks.rs"
+
 [features]
 # Builds the machine-wide binaries: the Windows service and tray, and the macOS uninstaller.
 machine-wide = []

core/src/aliasing/managers/bun.rs

@@ -11,4 +11,5 @@ pub static BUN: Manager = Manager {
         ("npm_config_registry", "http://registry.npmjs.org/"),
     ],
     args: &[],
+    lockfile: None,
 };

core/src/aliasing/managers/cargo.rs

@@ -17,4 +17,5 @@ pub static CARGO: Manager = Manager {
             "source.firewall.registry=\"sparse+http://index.crates.io/\"",
         ],
     }],
+    lockfile: None,
 };

core/src/aliasing/managers/gem.rs

@@ -8,4 +8,5 @@ pub static GEM: Manager = Manager {
         when: &["install", "update", "fetch"],
         flags: &["--clear-sources", "--source", "http://rubygems.org/"],
     }],
+    lockfile: None,
 };

core/src/aliasing/managers/go.rs

@@ -11,4 +11,5 @@ pub static GO: Manager = Manager {
         ("GOFLAGS", "-mod=mod"),
     ],
     args: &[],
+    lockfile: None,
 };

core/src/aliasing/managers/mod.rs

@@ -36,6 +36,8 @@ pub struct Manager {
     pub command: &'static str,
     pub env: &'static [(&'static str, &'static str)],
     pub args: &'static [Args],
+    /// Where the manager records registry URLs, which then carry our http:// override.
+    pub lockfile: Option<&'static str>,
 }
 
 pub static MANAGERS: &[&Manager] =

core/src/aliasing/managers/npm.rs

@@ -8,4 +8,5 @@ pub static NPM: Manager = Manager {
         ("npm_config_registry", "http://registry.npmjs.org/"),
     ],
     args: &[],
+    lockfile: Some("package-lock.json"),
 };

core/src/aliasing/managers/pdm.rs

@@ -13,4 +13,5 @@ pub static PDM: Manager = Manager {
         ("PDM_PYPI_VERIFY_SSL", "false"),
     ],
     args: &[],
+    lockfile: None,
 };

core/src/aliasing/managers/pip.rs

@@ -12,5 +12,5 @@ pub static PIP: Manager = recipe("pip");
 pub static PIP3: Manager = recipe("pip3");
 
 const fn recipe(name: &'static str) -> Manager {
-    Manager { command: name, env: PIP_ENV, args: &[] }
+    Manager { command: name, env: PIP_ENV, args: &[], lockfile: None }
 }

core/src/aliasing/managers/pipenv.rs

@@ -13,4 +13,5 @@ pub static PIPENV: Manager = Manager {
         ("PIP_TRUSTED_HOST", "pypi.org files.pythonhosted.org"),
     ],
     args: &[],
+    lockfile: None,
 };

core/src/aliasing/managers/pnpm.rs

@@ -9,4 +9,5 @@ pub static PNPM: Manager = Manager {
         ("pnpm_config_registry", "http://registry.npmjs.org/"),
     ],
     args: &[],
+    lockfile: None,
 };

core/src/aliasing/managers/uv.rs

@@ -4,4 +4,5 @@ pub static UV: Manager = Manager {
     command: "uv",
     env: &[("HTTP_PROXY", PROXY), ("http_proxy", PROXY), ("UV_DEFAULT_INDEX", PYPI_SIMPLE)],
     args: &[],
+    lockfile: Some("uv.lock"),
 };

core/src/aliasing/mod.rs

@@ -6,9 +6,11 @@ mod windows;
 pub use forward::spawn;
 pub use managers::*;
 
+use crate::policies::registries::BUILT_IN;
 use std::io::{Error, ErrorKind};
 use std::path::{Path, PathBuf};
 use std::process::Command;
+use tracing::warn;
 
 pub struct Invocation {
     pub program: String,
@@ -50,10 +52,23 @@ pub fn run(port: u16, invocation: &Invocation, dir: Option<&Path>) -> std::io::R
     let status = command.status();
     #[cfg(windows)]
     let status = status.map_err(|error| windows::explain(error, &program));
-    Ok(status?.code().unwrap_or(1))
+    let code = status?.code().unwrap_or(1);
+    let manager = MANAGERS.iter().find(|manager| manager.command == invocation.program);
+    if let Some(lockfile) = manager.and_then(|manager| manager.lockfile) {
+        warn_if_plaintext(lockfile, dir);
+    }
+    Ok(code)
 }
 
 // Command::new only finds .exe on Windows; npm, pnpm and gem are .cmd shims found via PATHEXT.
 fn resolve(program: &str) -> std::io::Result<PathBuf> {
     which::which(program).map_err(|e| Error::new(ErrorKind::NotFound, e))
 }
+
+fn warn_if_plaintext(lockfile: &str, dir: Option<&Path>) {
+    let path = dir.unwrap_or(Path::new(".")).join(lockfile);
+    let Ok(text) = std::fs::read_to_string(path) else { return };
+    if BUILT_IN.iter().any(|registry| text.contains(&format!("http://{}/", registry.host()))) {
+        warn!("{lockfile} has http:// registry URLs; change them to https:// before committing");
+    }
+}

core/src/blocks.rs

@@ -1,14 +1,25 @@
+use crate::config::{self, AllowedPackage};
 use crate::policies::Package;
+use crate::Firewall;
+use rama::error::BoxError;
 use serde::Serialize;
+use std::path::Path;
 use std::sync::Mutex;
+use std::time::{Duration, Instant};
+use tokio::sync::watch;
 
-/// Bounded, so blocks pile up harmlessly while nothing collects them.
+/// So blocks can't pile up while no app collects them.
 const KEPT: usize = 50;
+/// Under pip's, pipenv's and pdm's 15 s read timeout, the shortest of the supported managers.
+const HOLD: Duration = Duration::from_secs(10);
+/// Only hold while an app is asking for blocks, so someone can answer.
+const WATCHED: Duration = Duration::from_secs(2);
+/// For a minute, so the rest of that install can fetch it too.
+const ONCE: Duration = Duration::from_secs(60);
 
-static RECENT: Mutex<Vec<BlockedPackage>> = Mutex::new(Vec::new());
-
-#[derive(Serialize)]
+#[derive(Clone, Serialize)]
 pub struct BlockedPackage {
+    pub id: u64,
     pub eco: &'static str,
     pub name: String,
     pub version: Option<String>,
@@ -16,21 +27,125 @@ pub struct BlockedPackage {
     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);
+struct Blocks {
+    last_id: u64,
+    unsent: Vec<BlockedPackage>,
+    /// Age holds, the only blocks that can be allowed, each with what wakes its waiting downloads.
+    held: Vec<(BlockedPackage, watch::Sender<bool>)>,
+    polled: Option<Instant>,
+}
+
+static BLOCKS: Mutex<Blocks> =
+    Mutex::new(Blocks { last_id: 0, unsent: Vec::new(), held: Vec::new(), polled: None });
+
+/// Records a block and holds a new package's download for up to `HOLD`. Returns whether it was allowed.
+pub async fn block(eco: &'static str, pkg: &Package, filter: &'static str, reason: &str) -> bool {
+    let Some(mut answer) = record(eco, pkg, filter, reason) else {
+        return false;
+    };
+    let allowed = tokio::time::timeout(HOLD, answer.wait_for(|allowed| *allowed)).await;
+    matches!(allowed, Ok(Ok(_)))
+}
+
+/// The app's requests: `blocks`, `allow <id>` or `allow-once <id>`.
+/// An allow replies `late` if the download had stopped waiting.
+pub fn answer(firewall: &Firewall, config: &Path, request: &str) -> String {
+    if request == "blocks" {
+        return serde_json::to_string(&take()).expect("blocks serialize");
     }
-    recent.push(BlockedPackage {
+    let result = match request.split_once(' ').map(|(verb, id)| (verb, id.parse())) {
+        Some(("allow", Ok(id))) => trust(firewall, config, id),
+        Some(("allow-once", Ok(id))) => allow_once(firewall, id),
+        _ => Err(format!("unknown message {request}").into()),
+    };
+    match result {
+        Ok(true) => "ok".to_owned(),
+        Ok(false) => "late".to_owned(),
+        Err(error) => format!("error: {error}"),
+    }
+}
+
+/// Hands each block over once.
+fn take() -> Vec<BlockedPackage> {
+    let mut blocks = lock();
+    blocks.polled = Some(Instant::now());
+    std::mem::take(&mut blocks.unsent)
+}
+
+fn record(
+    eco: &'static str,
+    pkg: &Package,
+    filter: &'static str,
+    reason: &str,
+) -> Option<watch::Receiver<bool>> {
+    let mut blocks = lock();
+    let watched = blocks.polled.is_some_and(|polled| polled.elapsed() < WATCHED);
+    let holds = filter == "age" && watched;
+    // A repeat fetch of a held package waits on the same answer.
+    let waiting = blocks.held.iter().find(|(held, wake)| {
+        wake.receiver_count() > 0 && held.eco == eco && held.name == pkg.name && held.version == pkg.version
+    });
+    if let (true, Some((_, wake))) = (holds, waiting) {
+        return Some(wake.subscribe());
+    }
+    blocks.last_id += 1;
+    let block = BlockedPackage {
+        id: blocks.last_id,
         eco,
         name: pkg.name.clone(),
         version: pkg.version.clone(),
         filter,
         reason: reason.to_owned(),
-    });
+    };
+    push(&mut blocks.unsent, block.clone());
+    if filter != "age" {
+        return None;
+    }
+    let (wake, allowed) = watch::channel(false);
+    push(&mut blocks.held, (block, wake));
+    holds.then_some(allowed)
 }
 
-/// Hands each block over once.
-pub fn take() -> Vec<BlockedPackage> {
-    std::mem::take(&mut *RECENT.lock().unwrap_or_else(|e| e.into_inner()))
+/// Also saved to the config, so it survives a restart.
+fn trust(firewall: &Firewall, config: &Path, id: u64) -> Result<bool, BoxError> {
+    let block = held(id)?;
+    let version = block.version.ok_or("only a version can be trusted")?;
+    config::allow(config, block.eco, &block.name, &version)?;
+    let package = AllowedPackage { name: block.name, version: Some(version) };
+    firewall.lift_age_check(block.eco, package, None);
+    Ok(release(id))
+}
+
+fn allow_once(firewall: &Firewall, id: u64) -> Result<bool, BoxError> {
+    let block = held(id)?;
+    let package = AllowedPackage { name: block.name, version: block.version };
+    firewall.lift_age_check(block.eco, package, Some(Instant::now() + ONCE));
+    Ok(release(id))
+}
+
+fn held(id: u64) -> Result<BlockedPackage, BoxError> {
+    let blocks = lock();
+    let held = blocks.held.iter().find(|(held, _)| held.id == id);
+    Ok(held.ok_or(format!("no new package was held back as {id}"))?.0.clone())
+}
+
+/// Returns whether a download was still waiting.
+fn release(id: u64) -> bool {
+    let blocks = lock();
+    let Some((_, wake)) = blocks.held.iter().find(|(held, _)| held.id == id) else {
+        return false;
+    };
+    wake.send_replace(true);
+    wake.receiver_count() > 0
+}
+
+fn push<T>(list: &mut Vec<T>, item: T) {
+    if list.len() == KEPT {
+        list.remove(0);
+    }
+    list.push(item);
+}
+
+fn lock() -> std::sync::MutexGuard<'static, Blocks> {
+    BLOCKS.lock().unwrap_or_else(|e| e.into_inner())
 }

core/src/config/mod.rs

@@ -121,7 +121,7 @@ fn merge(base: &mut Map<String, Value>, top: Map<String, Value>) {
 }
 
 /// Adds an `allow` entry to the file, leaving the rest of it as written.
-pub fn allow(path: &Path, eco: &str, name: &str, version: Option<&str>) -> std::io::Result<()> {
+pub fn allow(path: &Path, eco: &str, name: &str, version: &str) -> std::io::Result<()> {
     let invalid = |e: String| Error::new(ErrorKind::InvalidData, format!("{}: {e}", path.display()));
     let mut config = match std::fs::read_to_string(path) {
         Ok(text) => serde_json::from_str(&text).map_err(|e| invalid(e.to_string()))?,

core/src/firewall.rs

@@ -1,4 +1,4 @@
-use crate::config::FirewallConfig;
+use crate::config::{AllowedPackage, FirewallConfig};
 use crate::policies::filters::age::Age;
 use crate::policies::filters::denylist::Denylist;
 use crate::policies::filters::osv::Osv;
@@ -6,12 +6,16 @@ use crate::policies::filters::Filter;
 use crate::policies::registries::*;
 use regex::Regex;
 use std::collections::HashMap;
+use std::sync::Mutex;
+use std::time::Instant;
 
 pub struct Firewall {
     pub config: FirewallConfig,
     registries: Vec<&'static Registry>,
     patterns: HashMap<&'static str, Vec<Regex>>,
     filters: Vec<Box<dyn Filter>>,
+    /// Each lift expires at its time, or lasts until the firewall stops. Never saved.
+    age_lifted: Mutex<Vec<(String, AllowedPackage, Option<Instant>)>>,
 }
 
 impl Default for Firewall {
@@ -34,7 +38,7 @@ impl Firewall {
         if config.min_age_hours > 0 {
             filters.push(Box::new(Age::new(config.min_age_hours)));
         }
-        Firewall { config, registries, patterns, filters }
+        Firewall { config, registries, patterns, filters, age_lifted: Mutex::default() }
     }
 
     pub fn match_on<'a>(
@@ -72,6 +76,19 @@ impl Firewall {
     pub fn filters(&self) -> &[Box<dyn Filter>] {
         &self.filters
     }
+
+    pub fn lift_age_check(&self, eco: &str, package: AllowedPackage, until: Option<Instant>) {
+        let mut lifted = self.age_lifted.lock().unwrap_or_else(|e| e.into_inner());
+        lifted.retain(|(_, _, until)| until.is_none_or(|until| until > Instant::now()));
+        lifted.push((eco.to_owned(), package, until));
+    }
+
+    pub fn age_check_lifted(&self, eco: &str, matches: impl Fn(&AllowedPackage) -> bool) -> bool {
+        let lifted = self.age_lifted.lock().unwrap_or_else(|e| e.into_inner());
+        lifted.iter().any(|(e, package, until)| {
+            e == eco && until.is_none_or(|until| until > Instant::now()) && matches(package)
+        })
+    }
 }
 
 /// The built-ins, then a copy of one per mirror. Leaked, as a `Registry` is `'static` everywhere.

core/src/os/macos/mod.rs

@@ -4,7 +4,7 @@ mod uninstall;
 
 pub use uninstall::uninstall;
 
-use crate::config::{self, FirewallConfig};
+use crate::config::FirewallConfig;
 use crate::{blocks, mitm, telemetry};
 use crate::Firewall;
 use rama::bytes::Bytes;
@@ -22,7 +22,6 @@ use rama::net::apple::networkextension::{transparent_proxy_ffi, NwTcpStream, Tcp
 use rama::rt::Executor;
 use rama::telemetry::tracing::apple::oslog::{OsLogLayer, Privacy};
 use rama::{Layer, Service};
-use serde::Deserialize;
 use std::convert::Infallible;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -40,6 +39,7 @@ const CONFIG_FILE: &str = "/Library/Application Support/Firewall/config.json";
 struct Handler {
     ca: Arc<mitm::CertificateAuthority>,
     hosts: Vec<&'static str>,
+    firewall: Arc<Firewall>,
     service: mitm::MitmService,
 }
 
@@ -59,12 +59,7 @@ 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 => match other.strip_prefix("allow ").map(allow) {
-                Some(Ok(())) => "ok".to_owned(),
-                Some(Err(error)) => format!("error: {error}"),
-                None => format!("error: unknown message {other}"),
-            },
+            other => blocks::answer(&self.firewall, CONFIG_FILE.as_ref(), other),
         }))
     }
 
@@ -119,22 +114,8 @@ fn handler(exec: Executor) -> Result<Handler, BoxError> {
     let signer: mitm::CaSigner = Arc::new(key);
     let ca = install::certificate_authority(&hosts, &*signer);
     let ca = Arc::new(ca.inspect_err(|_| telemetry::error("ca"))?);
-    let service = mitm::mitm_service(firewall, &ca, signer, None, exec);
-    Ok(Handler { ca, hosts, service })
-}
-
-#[derive(Deserialize)]
-struct AllowRequest {
-    eco: String,
-    name: String,
-    version: Option<String>,
-}
-
-/// Takes effect when the provider restarts, which rebuilds it from the config.
-fn allow(request: &str) -> Result<(), BoxError> {
-    let request: AllowRequest = serde_json::from_str(request)?;
-    config::allow(CONFIG_FILE.as_ref(), &request.eco, &request.name, request.version.as_deref())?;
-    Ok(())
+    let service = mitm::mitm_service(firewall.clone(), &ca, signer, None, exec);
+    Ok(Handler { ca, hosts, firewall, service })
 }
 
 /// stderr is invisible in a system extension, so events go to the unified log:

core/src/os/windows/pipe.rs

@@ -1,24 +1,32 @@
-//! How the tray asks the service what it blocked, as the macOS app messages its extension.
+//! How the tray asks the service what it blocked, and allows a new package once, as the macOS
+//! app messages its extension.
 
-use super::security_descriptor;
-use crate::blocks;
+use super::{config_file, security_descriptor};
+use crate::{blocks, Firewall};
 use rama::error::BoxError;
+use std::os::windows::io::AsRawHandle;
+use std::sync::Arc;
 use std::time::Duration;
 use tokio::io::{AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader};
 use tokio::net::windows::named_pipe::{NamedPipeServer, ServerOptions};
+use windows::core::{Owned, PWSTR};
+use windows::Win32::Foundation::HANDLE;
 use windows::Win32::Security::SECURITY_ATTRIBUTES;
+use windows::Win32::System::Pipes::GetNamedPipeClientProcessId;
+use windows::Win32::System::Threading::*;
 
 pub(super) const PIPE: &str = r"\\.\pipe\StrixFirewall";
 /// Signed-in users can connect, as the tray runs as them.
 const PIPE_ACL: &str = "D:P(A;;GA;;;SY)(A;;GA;;;BA)(A;;GRGW;;;IU)";
 
-pub(super) async fn serve() -> Result<(), BoxError> {
+pub(super) async fn serve(firewall: Arc<Firewall>) -> Result<(), BoxError> {
     let mut server = create(true)?;
     loop {
         server.connect().await?;
         let client = std::mem::replace(&mut server, create(false)?);
+        let firewall = Arc::clone(&firewall);
         tokio::spawn(async move {
-            if let Err(error) = answer(client).await {
+            if let Err(error) = answer(client, &firewall).await {
                 tracing::debug!(%error, "could not answer the tray");
             }
         });
@@ -40,19 +48,39 @@ fn create(first: bool) -> Result<NamedPipeServer, BoxError> {
 }
 
 /// A line each way.
-async fn answer(client: NamedPipeServer) -> Result<(), BoxError> {
+async fn answer(client: NamedPipeServer, firewall: &Firewall) -> Result<(), BoxError> {
     let mut client = BufReader::new(client);
     let mut request = String::new();
     (&mut client)
         .take(64 * 1024)
         .read_line(&mut request)
         .await?;
-    let reply = match request.trim_end() {
-        "blocks" => serde_json::to_string(&blocks::take())?,
-        other => format!("error: unknown request {other}"),
+    let request = request.trim_end();
+    // Only the app can message the macOS extension; here any program could connect.
+    let reply = if !client_is_tray(client.get_ref())? {
+        "error: only the tray can ask".to_owned()
+    } else if request.starts_with("allow ") {
+        // Trusting writes the config for every user, so it is left to an administrator.
+        "error: trusting a package takes an administrator".to_owned()
+    } else {
+        blocks::answer(firewall, &config_file(), request)
     };
     client.write_all(format!("{reply}\n").as_bytes()).await?;
     // Closing before the tray hangs up could discard the reply.
     let _ = tokio::time::timeout(Duration::from_secs(5), client.read(&mut [0])).await;
     Ok(())
 }
+
+fn client_is_tray(client: &NamedPipeServer) -> Result<bool, BoxError> {
+    let mut id = 0;
+    unsafe { GetNamedPipeClientProcessId(HANDLE(client.as_raw_handle()), &mut id)? };
+    let process = unsafe { Owned::new(OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, false, id)?) };
+    let mut path = [0u16; 1024];
+    let mut len = path.len() as u32;
+    let flags = PROCESS_NAME_WIN32;
+    unsafe { QueryFullProcessImageNameW(*process, flags, PWSTR(path.as_mut_ptr()), &mut len)? };
+    let path = String::from_utf16(&path[..len as usize])?;
+    let tray = std::env::current_exe()?.with_file_name("firewall-tray.exe");
+    // Windows paths ignore case.
+    Ok(path.to_lowercase() == tray.to_string_lossy().to_lowercase())
+}

core/src/os/windows/service.rs

@@ -155,8 +155,9 @@ async fn start_screening(status: &ServiceStatusHandle) -> Result<Vec<&'static st
     let crl = HttpServer::auto(exec.clone()).service(crl);
     tokio::spawn(listen_on(CRL_ADDRESS, 80, &exec)?.serve(crl));
 
-    tokio::spawn(async {
-        if let Err(error) = pipe::serve().await {
+    let tray_firewall = Arc::clone(&firewall);
+    tokio::spawn(async move {
+        if let Err(error) = pipe::serve(tray_firewall).await {
             tracing::error!(%error, "the tray cannot reach the service");
         }
     });

core/src/os/windows/tray.rs

@@ -2,10 +2,11 @@
 
 use super::pipe::PIPE;
 use super::*;
-use muda::{Menu, MenuEvent, MenuItem, PredefinedMenuItem, Submenu};
+use muda::{IsMenuItem, Menu, MenuEvent, MenuItem, PredefinedMenuItem, Submenu};
 use serde::Deserialize;
 use std::io::{BufRead, BufReader, Cursor, Write};
 use std::os::windows::io::AsRawHandle;
+use std::sync::mpsc::{channel, Receiver, Sender};
 use std::time::Duration;
 use tray_icon::{Icon, MouseButtonState, TrayIcon, TrayIconBuilder, TrayIconEvent};
 use windows::core::{w, PCWSTR};
@@ -22,6 +23,8 @@ const MENU_PAUSE: &str = "pause";
 const MENU_RESTART: &str = "restart";
 const MENU_LOG: &str = "log";
 const MENU_QUIT: &str = "quit";
+/// Also the service's request.
+const ALLOW_ONCE: &str = "allow-once";
 const LOGO: &[u8] = include_bytes!("tray.png");
 /// Where blocked packages are listed, below Open logs.
 const BLOCKED_AT: usize = 5;
@@ -62,9 +65,11 @@ pub fn run() -> Result<(), BoxError> {
         menu,
         blocked_separator,
         blocked: Vec::new(),
+        allowed: channel(),
     };
     tray.update();
-    unsafe { SetTimer(None, 0, 2000, None) };
+    // The service holds a new package's download only while it is asked this often.
+    unsafe { SetTimer(None, 0, 500, None) };
     let mut message = MSG::default();
     while unsafe { GetMessageW(&mut message, None, 0, 0) }.0 > 0 {
         unsafe { DispatchMessageW(&message) };
@@ -112,10 +117,13 @@ struct Tray {
     blocked_separator: PredefinedMenuItem,
     /// The most recent, as the menu lists them.
     blocked: Vec<BlockedPackage>,
+    /// Allowed from another thread, so no longer listed.
+    allowed: (Sender<BlockedPackage>, Receiver<BlockedPackage>),
 }
 
 #[derive(Clone, PartialEq, Deserialize)]
 struct BlockedPackage {
+    id: u64,
     eco: String,
     name: String,
     version: Option<String>,
@@ -136,6 +144,11 @@ impl BlockedPackage {
     fn malicious(&self) -> bool {
         self.filter != "age"
     }
+
+    /// Malware is never allowed, and a new package only by version.
+    fn trustable(&self) -> bool {
+        !self.malicious() && self.version.is_some()
+    }
 }
 
 impl Tray {
@@ -161,6 +174,11 @@ impl Tray {
 
     /// The service hands each block over once, so whichever tray asks first shows it.
     fn collect_blocks(&mut self) {
+        let allowed: Vec<_> = self.allowed.1.try_iter().collect();
+        if !allowed.is_empty() {
+            self.blocked.retain(|blocked| !allowed.contains(blocked));
+            self.list_blocked();
+        }
         if self.state != Some(ServiceState::Running) {
             return;
         }
@@ -184,7 +202,14 @@ impl Tray {
         self.blocked.drain(..excess);
         self.list_blocked();
         // Off the UI thread, so the menu keeps working while they are open.
-        std::thread::spawn(move || new.iter().for_each(alert));
+        let allowed = self.allowed.0.clone();
+        std::thread::spawn(move || {
+            for package in new {
+                if alert(&package) {
+                    allow_once(package, &allowed);
+                }
+            }
+        });
     }
 
     fn list_blocked(&self) {
@@ -204,14 +229,28 @@ impl Tray {
                 package.reason.clone()
             };
             let reason = MenuItem::new(reason, false, None);
+            let once = MenuItem::with_id(format!("{ALLOW_ONCE}:{i}"), "Allow Once", true, None);
+            let items: &[&dyn IsMenuItem] = if package.trustable() {
+                &[&reason, &once]
+            } else {
+                &[&reason]
+            };
             let label = format!("{verb} {}", package.label());
-            if let Ok(item) = Submenu::with_items(label, true, &[&reason]) {
+            if let Ok(item) = Submenu::with_items(label, true, items) {
                 let _ = self.menu.insert(&item, BLOCKED_AT + 1 + i);
             }
         }
     }
 
     fn on_menu(&self, id: &str) {
+        if let Some(i) = id.strip_prefix(ALLOW_ONCE).and_then(|i| i.strip_prefix(':')) {
+            let package = i.parse().ok().and_then(|i: usize| self.blocked.get(i));
+            if let Some(package) = package.cloned() {
+                let allowed = self.allowed.0.clone();
+                std::thread::spawn(move || allow_once(package, &allowed));
+            }
+            return;
+        }
         let state = self.state;
         let screening = state == Some(ServiceState::Running);
         let action: fn() -> Result<(), BoxError> = match id {
@@ -237,7 +276,8 @@ impl Tray {
     }
 }
 
-fn alert(package: &BlockedPackage) {
+/// Whether the user chose to allow it once.
+fn alert(package: &BlockedPackage) -> bool {
     let text = format!("{} {}.", package.label(), package.reason);
     let (title, text, style) = if package.malicious() {
         let title = format!("Blocked malware: {}", package.label());
@@ -245,11 +285,33 @@ fn alert(package: &BlockedPackage) {
             + "\n\nIt was not installed. Don't install it from another source. If you didn't expect this "
             + "package, a dependency may be compromised; tell your security team.";
         (title, text, MB_ICONERROR)
-    } else {
+    } else if !package.trustable() {
         ("Held back a new package".to_owned(), text, MB_ICONINFORMATION)
+    } else {
+        let text = text + "\n\nAllow it once?";
+        ("Held back a new package".to_owned(), text, MB_YESNO | MB_ICONINFORMATION)
     };
     let (title, text) = (HSTRING::from(title), HSTRING::from(text));
-    unsafe { MessageBoxW(None, &text, &title, style | MB_SETFOREGROUND) };
+    unsafe { MessageBoxW(None, &text, &title, style | MB_SETFOREGROUND) == IDYES }
+}
+
+/// Tells the user when the install had already stopped waiting.
+fn allow_once(package: BlockedPackage, allowed: &Sender<BlockedPackage>) {
+    let reply = match ask_service(&format!("{ALLOW_ONCE} {}", package.id)) {
+        Ok(reply) => reply,
+        Err(error) => return show_error(error),
+    };
+    match reply.as_str() {
+        "ok" => {}
+        "late" => {
+            let title = format!("Allowed {} for the next minute", package.label());
+            let text = "The install had already stopped waiting for it. Run it again to finish.";
+            let (title, text) = (HSTRING::from(title), HSTRING::from(text));
+            unsafe { MessageBoxW(None, &text, &title, MB_ICONINFORMATION | MB_SETFOREGROUND) };
+        }
+        other => return show_error(other.into()),
+    }
+    let _ = allowed.send(package);
 }
 
 /// One request per connection, as the service answers.

core/src/policies/filters/mod.rs

@@ -3,6 +3,7 @@ pub mod denylist;
 pub mod osv;
 
 use super::registries::{Package, Registry};
+use crate::config::AllowedPackage;
 use crate::Firewall;
 use std::future::Future;
 use std::pin::Pin;
@@ -31,10 +32,11 @@ pub async fn consult(
     registry: &'static Registry,
     pkg: &Package,
 ) -> Option<(&'static str, Verdict)> {
-    let allowed = allowed(firewall, registry, pkg);
+    let lifted = allowed(firewall, registry, pkg)
+        || firewall.age_check_lifted(registry.eco, |entry| matches(registry, pkg, entry));
     let mut unsure = None;
     for filter in firewall.filters() {
-        if allowed && filter.name() == "age" {
+        if lifted && filter.name() == "age" {
             continue;
         }
         match filter.check(registry, pkg).await {
@@ -51,13 +53,15 @@ fn allowed(firewall: &Firewall, registry: &Registry, pkg: &Package) -> bool {
     let Some(entries) = firewall.config.allow.get(registry.eco) else {
         return false;
     };
-    entries.iter().any(|entry| {
-        let name_matches = match registry.normalize {
-            Some(normalize) => normalize(&entry.name) == pkg.name,
-            None => entry.name == pkg.name,
-        };
-        // Go writes a leading v that the parsed version drops, and PEP 440 ignores one.
-        let version = entry.version.as_deref().map(|v| v.strip_prefix('v').unwrap_or(v));
-        name_matches && (version.is_none() || version == pkg.version.as_deref())
-    })
+    entries.iter().any(|entry| matches(registry, pkg, entry))
+}
+
+fn matches(registry: &Registry, pkg: &Package, entry: &AllowedPackage) -> bool {
+    let name_matches = match registry.normalize {
+        Some(normalize) => normalize(&entry.name) == pkg.name,
+        None => entry.name == pkg.name,
+    };
+    // Go writes a leading v that the parsed version drops, and PEP 440 ignores one.
+    let version = entry.version.as_deref().map(|v| v.strip_prefix('v').unwrap_or(v));
+    name_matches && (version.is_none() || version == pkg.version.as_deref())
 }

core/src/policies/filters/osv.rs

@@ -41,7 +41,9 @@ impl Filter for Osv {
             if hits.is_empty() {
                 Verdict::Allow
             } else {
-                Verdict::Deny(format!("is flagged malicious by OSV ({})", hits.join(", ")))
+                let links: Vec<String> =
+                    hits.iter().map(|id| format!("{id} https://osv.dev/vulnerability/{id}")).collect();
+                Verdict::Deny(format!("is flagged malicious by OSV: {}", links.join(", ")))
             }
         })
     }

core/src/policies/mod.rs

@@ -70,7 +70,10 @@ 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);
+            if crate::blocks::block(registry.eco, &pkg, filter, &reason).await {
+                info!(eco = registry.eco, pkg = %pkg.label(), "allowed while held");
+                return None;
+            }
             Some(format!("{} {reason}", pkg.label()))
         }
         Some((filter, Verdict::Unknown(e))) if !firewall.config.fail_open => {

core/tests/blocks.rs

@@ -0,0 +1,27 @@
+use firewall::blocks::{answer, block};
+use firewall::policies::Package;
+use firewall::Firewall;
+use std::path::Path;
+use std::time::Duration;
+
+#[tokio::test]
+async fn allowing_once_releases_the_held_download() {
+    let firewall = Firewall::default();
+    let config = Path::new("/nonexistent/config.json");
+    let pkg = Package { name: "left-pad".into(), version: Some("1.3.0".into()) };
+    assert!(!block("npm", &pkg, "age", "is new").await, "held while nothing was asking");
+    answer(&firewall, config, "blocks");
+
+    let held = tokio::spawn(async move { block("npm", &pkg, "age", "is new").await });
+    let id = loop {
+        let blocks: serde_json::Value = serde_json::from_str(&answer(&firewall, config, "blocks")).unwrap();
+        if let Some(id) = blocks[0]["id"].as_u64() {
+            break id;
+        }
+        tokio::time::sleep(Duration::from_millis(10)).await;
+    };
+    assert_eq!(answer(&firewall, config, &format!("allow-once {id}")), "ok");
+    assert!(held.await.unwrap(), "the waiting download goes through");
+    assert!(firewall.age_check_lifted("npm", |p| p.name == "left-pad"), "and the rest of the install");
+    assert!(!block("npm", &Package { name: "evil".into(), version: None }, "denylist", "is malware").await);
+}

core/tests/config.rs

@@ -1,4 +1,4 @@
-use firewall::config::path;
+use firewall::config::{path, AllowedPackage};
 use firewall::policies::filters::consult;
 use firewall::policies::{screen, Package};
 use firewall::{Firewall, FirewallConfig};
@@ -95,12 +95,23 @@ async fn failing_closed_blocks_what_could_not_be_checked() {
     assert!(blocked.contains("could not be checked"), "{blocked:?}");
 }
 
+#[tokio::test]
+async fn lifting_the_age_check_still_checks_for_malware() {
+    let config = r#"{"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()) };
+    firewall.lift_age_check("go", AllowedPackage { name: pkg.name.clone(), version: None }, None);
+    let (filter, _) = consult(&firewall, registry, &pkg).await.expect("the denylist still runs");
+    assert_eq!(filter, "denylist");
+}
+
 #[test]
 fn allowing_keeps_the_rest_of_the_file() {
     let path = std::env::temp_dir().join(format!("firewall-allow-{}.json", std::process::id()));
     std::fs::write(&path, r#"{"fail_open": false}"#).expect("write");
     for _ in 0..2 {
-        firewall::config::allow(&path, "npm", "left-pad", Some("1.3.0")).expect("allow");
+        firewall::config::allow(&path, "npm", "left-pad", "1.3.0").expect("allow");
     }
     let text = std::fs::read_to_string(&path).expect("read");
     std::fs::remove_file(&path).ok();

macos/App/BlockAlerts.swift

@@ -2,13 +2,13 @@ import AppKit
 import Security
 
 struct BlockedPackage: Codable, Hashable, Identifiable {
+    let id: UInt64
     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" }
@@ -16,25 +16,61 @@ struct BlockedPackage: Codable, Hashable, Identifiable {
     var trustable: Bool { !malicious && version != nil }
 }
 
+enum Allowance {
+    /// For a minute, so the rest of that install can fetch it too.
+    case once
+    case always
+}
+
 @MainActor
 enum BlockAlert {
-    /// Returns whether the user chose to trust the package.
-    static func show(_ package: BlockedPackage) -> Bool {
+    static func show(_ package: BlockedPackage) -> Allowance? {
         let alert = NSAlert()
         alert.addButton(withTitle: "OK")
         if package.malicious {
             alert.alertStyle = .critical
             alert.messageText = "Blocked malware: \(package.label) (\(package.eco))"
-            alert.informativeText = "\(package.label) \(package.reason).\n\n"
+            setText(alert, "\(package.label) \(package.reason).\n\n"
                 + "It was not installed. Don't install it from another source. "
-                + "If you didn't expect this package, a dependency may be compromised; tell your security team."
+                + "If you didn't expect this package, a dependency may be compromised; tell your security team.")
         } else {
             alert.messageText = "Held back a new package"
-            alert.informativeText = "\(package.label) (\(package.eco)) \(package.reason)."
-            if package.trustable { alert.addButton(withTitle: "Trust this version") }
+            setText(alert, "\(package.label) (\(package.eco)) \(package.reason).")
+            if package.trustable {
+                alert.addButton(withTitle: "Allow Once")
+                alert.addButton(withTitle: "Trust this version")
+            }
         }
         NSApp.activate(ignoringOtherApps: true)
-        return alert.runModal() == .alertSecondButtonReturn
+        switch alert.runModal() {
+        case .alertSecondButtonReturn: return .once
+        case .alertThirdButtonReturn: return .always
+        default: return nil
+        }
+    }
+
+    static func late(_ package: BlockedPackage, _ allowance: Allowance) {
+        let alert = NSAlert()
+        alert.messageText = allowance == .once ? "Allowed \(package.label) for the next minute" : "Trusted \(package.label)"
+        alert.informativeText = "The install had already stopped waiting for it. Run it again to finish."
+        NSApp.activate(ignoringOtherApps: true)
+        alert.runModal()
+    }
+
+    /// An alert's own text is plain, so this text goes in a selectable field, where its links open on click.
+    private static func setText(_ alert: NSAlert, _ text: String) {
+        let linked = NSMutableAttributedString(string: text, attributes: [.font: NSFont.systemFont(ofSize: NSFont.smallSystemFontSize)])
+        let detector = try! NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
+        for match in detector.matches(in: text, range: NSRange(text.startIndex..., in: text)) {
+            if let url = match.url { linked.addAttribute(.link, value: url, range: match.range) }
+        }
+        let field = NSTextField(wrappingLabelWithString: "")
+        field.allowsEditingTextAttributes = true
+        field.isSelectable = true
+        field.attributedStringValue = linked
+        field.preferredMaxLayoutWidth = 300
+        field.frame.size = field.fittingSize
+        alert.accessoryView = field
     }
 }
 

macos/App/FirewallModel.swift

@@ -203,26 +203,22 @@ final class FirewallModel: NSObject, ObservableObject {
         if let url = URL(string: pane) { NSWorkspace.shared.open(url) }
     }
 
-    /// Allowing a version writes it into the extension's config, which a restart then loads.
-    func trust(_ package: BlockedPackage) async {
+    /// Trusting changes the config for every user, so it takes an admin.
+    func allow(_ package: BlockedPackage, _ allowance: Allowance) async {
         guard package.trustable else { return }
-        guard AdminAuthorization.confirm() else {
+        if allowance == .always, !AdminAuthorization.confirm() {
             log("Trust cancelled for \(package.label)")
             return
         }
         do {
-            var request = ["eco": package.eco, "name": package.name]
-            request["version"] = package.version
-            let json = String(decoding: try JSONSerialization.data(withJSONObject: request), as: UTF8.self)
-            let reply = try await providerMessage("allow \(json)")
-            guard reply == "ok" else { throw FirewallError.extensionRefused(reply) }
+            let reply = try await providerMessage("\(allowance == .once ? "allow-once" : "allow") \(package.id)")
+            guard reply == "ok" || reply == "late" else { throw FirewallError.extensionRefused(reply) }
             blocked.removeAll { $0 == package }
-            log("Trusted \(package.label) (\(package.eco))")
+            log("Allowed \(package.label) (\(package.eco)) \(allowance)")
+            if reply == "late" { BlockAlert.late(package, allowance) }
         } catch {
-            log("Could not trust \(package.label): \(error.localizedDescription)")
-            return
+            log("Could not allow \(package.label): \(error.localizedDescription)")
         }
-        await restart()
     }
 
     /// The extension cannot message the app, so the app asks it for blocks.
@@ -232,11 +228,11 @@ final class FirewallModel: NSObject, ObservableObject {
                let packages = try? JSONDecoder().decode([BlockedPackage].self, from: Data(reply.utf8)) {
                 for package in packages where !blocked.contains(package) {
                     blocked.append(package)
-                    if BlockAlert.show(package) { await trust(package) }
+                    if let allowance = BlockAlert.show(package) { await allow(package, allowance) }
                 }
                 blocked = Array(blocked.suffix(10))
             }
-            try? await Task.sleep(nanoseconds: 2_000_000_000)
+            try? await Task.sleep(nanoseconds: 500_000_000)
         }
     }
 

macos/App/MenuBarView.swift

@@ -29,8 +29,12 @@ struct MenuBarView: View {
                 if !package.malicious {
                     Menu("Held back \(package.label) (\(package.eco))") {
                         Text(package.reason)
+                        Button("Allow Once") {
+                            Task { await model.allow(package, .once) }
+                        }
+                        .disabled(model.busy || !package.trustable)
                         Button("Trust this version") {
-                            Task { await model.trust(package) }
+                            Task { await model.allow(package, .always) }
                         }
                         .disabled(model.busy || !package.trustable)
                     }