fix: audit fixes — power timeout, timing mitigation, release profile, GREETD_SOCK cache (v0.7.1)

- Add 30s timeout with SIGKILL to power actions (adapted from moonset)
- Add 500ms minimum login response time against timing enumeration
- Cache GREETD_SOCK in GreeterState at startup
- Add [profile.release] with LTO, codegen-units=1, strip
- Add compressed="true" to GResource CSS/SVG entries
- Add SYNC comments to duplicated blur/background functions
- Add nix dependency for signal handling in power timeout

Cargo.lock

@@ -59,6 +59,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
+
 [[package]]
 name = "equivalent"
 version = "1.0.2"
@@ -569,7 +575,7 @@ dependencies = [
 
 [[package]]
 name = "moongreet"
-version = "0.7.0"
+version = "0.7.1"
 dependencies = [
  "gdk-pixbuf",
  "gdk4",
@@ -580,6 +586,7 @@ dependencies = [
  "gtk4",
  "gtk4-layer-shell",
  "log",
+ "nix",
  "serde",
  "serde_json",
  "systemd-journal-logger",
@@ -588,6 +595,18 @@ dependencies = [
  "zeroize",
 ]
 
+[[package]]
+name = "nix"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.4"

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moongreet"
-version = "0.7.0"
+version = "0.7.1"
 edition = "2024"
 description = "A greetd greeter for Wayland with GTK4 and Layer Shell"
 license = "MIT"
@@ -16,6 +16,7 @@ toml = "0.8"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 graphene-rs = { version = "0.22", package = "graphene-rs" }
+nix = { version = "0.29", features = ["signal"] }
 zeroize = { version = "1", features = ["std"] }
 log = "0.4"
 systemd-journal-logger = "2.2"
@@ -23,5 +24,10 @@ systemd-journal-logger = "2.2"
 [dev-dependencies]
 tempfile = "3"
 
+[profile.release]
+lto = "thin"
+codegen-units = 1
+strip = true
+
 [build-dependencies]
 glib-build-tools = "0.22"

DECISIONS.md

@@ -1,5 +1,12 @@
 # Decisions
 
+## 2026-03-31 – Fourth audit: power timeout, timing mitigation, release profile, GREETD_SOCK caching
+
+- **Who**: Ragnar, Dom
+- **Why**: Fourth triple audit found moongreet power.rs had no timeout on loginctl (greeter could freeze), username enumeration via timing differential, GREETD_SOCK re-read on every login, missing release profile, and missing GResource compression.
+- **Tradeoffs**: 500ms minimum login response time adds slight delay on fast auth but prevents timing-based username enumeration. Power timeout (30s + SIGKILL) matches moonset pattern — aggressive but prevents greeter freeze.
+- **How**: (1) power.rs adapted from moonset with 30s timeout + SIGKILL (nix dependency added). (2) 500ms min response floor in attempt_login via Instant + glib::timeout_future. (3) GREETD_SOCK cached in GreeterState at startup. (4) `[profile.release]` with LTO, codegen-units=1, strip. (5) `compressed="true"` on GResource entries. (6) SYNC comments on duplicated blur/background functions.
+
 ## 2026-03-30 – Full audit fix: security, quality, performance (v0.6.2)
 
 - **Who**: Ragnar, Dom

resources/resources.gresource.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <gresources>
   <gresource prefix="/dev/moonarch/moongreet">
-    <file>style.css</file>
-    <file>default-avatar.svg</file>
+    <file compressed="true">style.css</file>
+    <file compressed="true">default-avatar.svg</file>
   </gresource>
 </gresources>

src/greeter.rs

@@ -133,6 +133,10 @@ pub fn load_background_texture(bg_path: &Path) -> Option<gdk::Texture> {
 
 // -- GPU blur via GskBlurNode -------------------------------------------------
 
+// SYNC: MAX_BLUR_DIMENSION, render_blurred_texture, and create_background_picture
+// are duplicated in moonlock/src/lockscreen.rs and moonset/src/panel.rs.
+// Changes here must be mirrored to the other two projects.
+
 /// Maximum texture dimension before downscaling for blur.
 /// Keeps GPU work reasonable on 4K+ displays.
 const MAX_BLUR_DIMENSION: f32 = 1920.0;
@@ -240,6 +244,7 @@ struct GreeterState {
     default_avatar_texture: Option<gdk::Texture>,
     failed_attempts: HashMap<String, u32>,
     greetd_sock: Arc<Mutex<Option<UnixStream>>>,
+    greetd_sock_path: Option<String>,
     login_cancelled: Arc<std::sync::atomic::AtomicBool>,
     fingerprint_available: bool,
     /// Incremented on each user switch to discard stale async results.
@@ -281,12 +286,16 @@ pub fn create_greeter_window(
         log::debug!("GTK theme: {theme}");
     }
 
+    // Cache GREETD_SOCK at startup — it never changes during runtime
+    let greetd_sock_path = std::env::var("GREETD_SOCK").ok().filter(|p| !p.is_empty());
+
     let state = Rc::new(RefCell::new(GreeterState {
         selected_user: None,
         avatar_cache: HashMap::new(),
         default_avatar_texture: None,
         failed_attempts: HashMap::new(),
         greetd_sock: Arc::new(Mutex::new(None)),
+        greetd_sock_path,
         login_cancelled: Arc::new(std::sync::atomic::AtomicBool::new(false)),
         fingerprint_available: false,
         user_switch_generation: 0,
@@ -960,9 +969,9 @@ fn attempt_login(
     session_dropdown: &gtk::DropDown,
 ) {
     log::debug!("Login attempt for user: {}", user.username);
-    let sock_path = match std::env::var("GREETD_SOCK") {
-        Ok(p) if !p.is_empty() => p,
-        _ => {
+    let sock_path = match state.borrow().greetd_sock_path.clone() {
+        Some(p) => p,
+        None => {
             show_error(error_label, password_entry, strings.greetd_sock_not_set);
             return;
         }
@@ -1009,6 +1018,8 @@ fn attempt_login(
         state,
         async move {
             let session_name_clone = session_name.clone();
+            // Minimum response time to prevent username enumeration via timing
+            let login_start = std::time::Instant::now();
             let result = gio::spawn_blocking(move || {
                 login_worker(
                     &username,
@@ -1022,6 +1033,11 @@ fn attempt_login(
                 )
             })
             .await;
+            let elapsed = login_start.elapsed();
+            let min_response = std::time::Duration::from_millis(500);
+            if elapsed < min_response {
+                glib::timeout_future(min_response - elapsed).await;
+            }
 
             match result {
                 Ok(Ok(LoginResult::Success { username })) => {

src/power.rs

@@ -2,11 +2,18 @@
 // ABOUTME: Wrappers around system commands for the greeter UI.
 
 use std::fmt;
-use std::process::Command;
+use std::io::Read;
+use std::process::{Command, Stdio};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::Arc;
+use std::time::Duration;
+
+const POWER_TIMEOUT: Duration = Duration::from_secs(30);
 
 #[derive(Debug)]
 pub enum PowerError {
     CommandFailed { action: &'static str, message: String },
+    Timeout { action: &'static str },
 }
 
 impl fmt::Display for PowerError {
@@ -15,41 +22,79 @@ impl fmt::Display for PowerError {
             PowerError::CommandFailed { action, message } => {
                 write!(f, "{action} failed: {message}")
             }
+            PowerError::Timeout { action } => {
+                write!(f, "{action} timed out")
+            }
         }
     }
 }
 
 impl std::error::Error for PowerError {}
 
-/// Run a command and return a PowerError on failure.
+/// Run a command with timeout and return a PowerError on failure.
+///
+/// Uses blocking `child.wait()` with a separate timeout thread that sends
+/// SIGKILL after POWER_TIMEOUT. This runs inside `gio::spawn_blocking`,
+/// so blocking is expected.
 fn run_command(action: &'static str, program: &str, args: &[&str]) -> Result<(), PowerError> {
     log::debug!("Power action: {action} ({program} {args:?})");
-    let child = Command::new(program)
+    let mut child = Command::new(program)
         .args(args)
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
         .spawn()
         .map_err(|e| PowerError::CommandFailed {
             action,
             message: e.to_string(),
         })?;
 
-    let output = child
-        .wait_with_output()
-        .map_err(|e| PowerError::CommandFailed {
-            action,
-            message: e.to_string(),
-        })?;
+    let child_pid = nix::unistd::Pid::from_raw(child.id() as i32);
+    let done = Arc::new(AtomicBool::new(false));
+    let done_clone = done.clone();
 
-    if output.status.success() {
-        log::debug!("Power action {action} completed successfully");
+    let timeout_thread = std::thread::spawn(move || {
+        let interval = Duration::from_millis(100);
+        let mut elapsed = Duration::ZERO;
+        while elapsed < POWER_TIMEOUT {
+            std::thread::sleep(interval);
+            if done_clone.load(Ordering::Relaxed) {
+                return;
+            }
+            elapsed += interval;
+        }
+        // ESRCH if the process already exited — harmless
+        let _ = nix::sys::signal::kill(child_pid, nix::sys::signal::Signal::SIGKILL);
+    });
+
+    let status = child.wait().map_err(|e| PowerError::CommandFailed {
+        action,
+        message: e.to_string(),
+    })?;
+
+    done.store(true, Ordering::Relaxed);
+    let _ = timeout_thread.join();
+
+    if status.success() {
+        log::debug!("Power action {action} completed");
+        Ok(())
     } else {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(PowerError::CommandFailed {
-            action,
-            message: format!("exit code {}: {}", output.status, stderr.trim()),
-        });
-    }
+        #[cfg(unix)]
+        {
+            use std::os::unix::process::ExitStatusExt;
+            if status.signal() == Some(9) {
+                return Err(PowerError::Timeout { action });
+            }
+        }
 
-    Ok(())
+        let mut stderr_buf = String::new();
+        if let Some(mut stderr) = child.stderr.take() {
+            let _ = stderr.read_to_string(&mut stderr_buf);
+        }
+        Err(PowerError::CommandFailed {
+            action,
+            message: format!("exit code {}: {}", status, stderr_buf.trim()),
+        })
+    }
 }
 
 /// Reboot the system via loginctl.
@@ -75,6 +120,12 @@ mod tests {
         assert_eq!(err.to_string(), "reboot failed: No such file or directory");
     }
 
+    #[test]
+    fn power_error_timeout_display() {
+        let err = PowerError::Timeout { action: "shutdown" };
+        assert_eq!(err.to_string(), "shutdown timed out");
+    }
+
     #[test]
     fn run_command_returns_error_for_missing_binary() {
         let result = run_command("test", "nonexistent-binary-xyz", &[]);
@@ -99,7 +150,7 @@ mod tests {
 
     #[test]
     fn run_command_passes_args() {
-        let result = run_command("test", "true", &["--ignored-arg"]);
+        let result = run_command("test", "echo", &["hello", "world"]);
         assert!(result.is_ok());
     }
 }