fix: audit fix — avoid latent stdout pipe deadlock in run_command (v0.8.3)

Piping stdout without draining while blocking in child.wait() risks deadlock
if a command writes more than one OS pipe buffer (~64 KB on Linux). Current
callers (systemctl, niri msg, loginctl) stay well under that, but the
structure was fragile. stdout is now discarded; stderr continues to be
captured for error reporting.

CHANGELOG.md

@@ -3,6 +3,19 @@
 All notable changes to this project will be documented in this file.
 Format based on [Keep a Changelog](https://keepachangelog.com/).
 
+## [0.8.0] - 2026-03-30
+
+### Changed
+
+- Replace `canonicalize()` with `symlink_metadata` + `is_file` + `!is_symlink` for avatar lookup — prevents symlink traversal to arbitrary files
+- Replace `canonicalize()` with same symlink-safe check in `resolve_background_path`
+- Downscale wallpaper to `MAX_BLUR_DIMENSION` (1920px) before GPU blur — prevents excessive memory use on high-res images
+- Validate `background_blur` per config source — invalid user value preserves system default instead of silently falling back to 0
+
+### Fixed
+
+- Fix blur padding offset from `(0,0)` to `(-pad,-pad)` to prevent edge darkening on blurred wallpaper
+
 ## [0.7.3] - 2026-03-29
 
 ### Fixed

CLAUDE.md

@@ -1,7 +1,5 @@
 # Moonset
 
-**Name**: Hekate (Göttin der Wegkreuzungen — passend zum Power-Menu, das den Weg der Session bestimmt)
-
 ## Projekt
 
 Moonset ist ein Wayland Session Power Menu, gebaut mit Rust + gtk4-rs + gtk4-layer-shell.

Cargo.lock

@@ -616,7 +616,7 @@ dependencies = [
 
 [[package]]
 name = "moonset"
-version = "0.8.0"
+version = "0.8.3"
 dependencies = [
  "dirs",
  "gdk-pixbuf",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "moonset"
-version = "0.8.0"
+version = "0.8.3"
 edition = "2024"
 description = "Wayland session power menu with GTK4 and Layer Shell"
 license = "MIT"
@@ -22,5 +22,10 @@ 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

@@ -2,79 +2,93 @@
 
 Architectural and design decisions for Moonset, in reverse chronological order.
 
+## 2026-04-24 – Audit fix: avoid latent stdout pipe deadlock in run_command (v0.8.3)
+
+- **Who**: ClaudeCode, Dom
+- **Why**: Audit found that `run_command` piped the child's `stdout` but never drained it, then called blocking `child.wait()`. A child writing more than one OS pipe buffer (~64 KB on Linux) would block on `write()` while the parent blocked in `wait()` — classic pipe deadlock, broken only by the 30 s SIGKILL timeout. Current callers (`systemctl`, `niri msg`, `loginctl`) do not emit that much output, but the structure was fragile and would bite on any future command or changed behaviour.
+- **Tradeoffs**: stdout is now fully discarded. If a future caller needs stdout, it will have to drain it concurrently with `wait()` (separate reader thread).
+- **How**: Replace `.stdout(Stdio::piped())` with `.stdout(Stdio::null())` in `run_command`. `stderr` stays piped — it is drained after `wait()`, which is safe because `wait()` already reaped the child and no further writes can occur.
+
+## 2026-03-31 – Fourth audit: release profile, GResource compression, lock stderr, sync markers
+
+- **Who**: ClaudeCode, Dom
+- **Why**: Fourth triple audit found missing release profile (LTO/strip), uncompressed GResource assets, moonlock stderr suppressed (errors invisible), and duplicated code without sync markers.
+- **Tradeoffs**: moonlock stderr now inherited instead of null — errors appear in moonset's journal context. Acceptable for debugging, no security leak since moonlock logs to its own journal identifier.
+- **How**: (1) `[profile.release]` with LTO, codegen-units=1, strip. (2) `compressed="true"` on GResource entries. (3) `Stdio::inherit()` for moonlock stderr in lock(). (4) SYNC comments on duplicated blur/background functions.
+
 ## 2026-03-28 – Remove wallpaper from GResource bundle
 
-- **Who**: Ragnar, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: All three Moon projects (moonset, moongreet, moonlock) embedded a 374kB fallback wallpaper in the binary via GResource. Moonarch already installs `/usr/share/moonarch/wallpaper.jpg` at system setup time, making the embedded fallback unnecessary dead weight (~2MB in binary size).
 - **Tradeoffs**: If `/usr/share/moonarch/wallpaper.jpg` is missing and no user config exists, moonset shows a solid CSS background instead of a wallpaper. Acceptable — the power menu is functional without a wallpaper image.
 - **How**: Removed `wallpaper.jpg` from GResource XML and resources directory. `resolve_background_path` returns `Option<PathBuf>`. All wallpaper-related functions handle `None` gracefully. Binary size dropped from ~3.2MB to ~1.3MB.
 
 ## 2026-03-28 – Switch from env_logger to systemd-journal-logger
 
-- **Who**: Ragnar, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: moonlock and moongreet already use systemd-journal-logger. moonset used env_logger which writes to stderr — not useful for a GUI app launched via keybind. Journal integration enables `journalctl -t moonset` and consistent troubleshooting across all three Moon projects.
 - **Tradeoffs**: Requires systemd at runtime. Graceful fallback to eprintln if journal logger fails. Acceptable since Moonarch targets systemd-based Arch Linux.
 - **How**: Replace `env_logger` dep with `systemd-journal-logger`, add `setup_logging()` with `MOONSET_DEBUG` env var for debug-level output. Same pattern as moonlock/moongreet.
 
 ## 2026-03-28 – Replace action name dispatch with `quit_after` field
 
-- **Who**: Hekate, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Post-action behavior (quit the app or not) was controlled by comparing `action_name == "lock"` — a magic string duplicated from the action definition. Renaming an action would silently break the dispatch.
 - **Tradeoffs**: Adds a field to `ActionDef` that most actions set to `false`. Acceptable because it makes the contract explicit and testable.
 - **How**: `ActionDef.quit_after: bool` — `true` for lock and logout, `false` for hibernate/reboot/shutdown.
 
 ## 2026-03-28 – GPU blur via GskBlurNode replaces CPU blur
 
-- **Who**: Ragnar, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: CPU-side Gaussian blur (`image` crate) blocked startup and added caching complexity. moonlock already migrated to GPU blur.
 - **Tradeoffs**: GPU blur quality is slightly different (box-blur approximation vs true Gaussian), acceptable for wallpaper backgrounds. Removes `image` crate dependency entirely. No disk cache needed.
 - **How**: `Snapshot::push_blur()` + `GskRenderer::render_texture()` on `connect_realize`. Blur happens once on the GPU when the widget gets its renderer. Symmetric with moonlock and moongreet.
 
 ## 2026-03-28 – Use absolute paths for system binaries
 
-- **Who**: Hekate, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Security audit flagged PATH hijacking risk — relative binary names allow a malicious `$PATH` entry to intercept `systemctl`, `loginctl`, etc.
 - **Tradeoffs**: Hardcoded paths reduce portability to non-Arch distros where binaries may live elsewhere (e.g. `/sbin/`). Acceptable because Moonarch targets Arch Linux exclusively.
 - **How**: All five power action wrappers now use `/usr/bin/` prefixed paths.
 
 ## 2026-03-28 – Implement power action timeout via try_wait polling
 
-- **Who**: Hekate, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: `POWER_TIMEOUT` and `PowerError::Timeout` were declared but never wired up. A hanging `systemctl hibernate` (e.g. blocked NFS mount) would freeze the power menu indefinitely.
 - **Tradeoffs**: Polling with `try_wait()` + 100ms sleep is slightly less efficient than a dedicated timeout crate, but avoids adding a dependency for a single use case.
 - **How**: `run_command` now polls `child.try_wait()` against a 30s deadline, kills the child on timeout.
 
 ## 2026-03-28 – Centralize GRESOURCE_PREFIX
 
-- **Who**: Hekate, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: The string `/dev/moonarch/moonset` was duplicated in `config.rs`, `users.rs`, and as literal strings in `panel.rs` and `main.rs`. Changing the application ID would require edits in 4+ locations.
 - **Tradeoffs**: Modules now depend on `crate::GRESOURCE_PREFIX` — tighter coupling to main.rs, but acceptable for an internal constant.
 - **How**: Single `pub(crate) const GRESOURCE_PREFIX` in `main.rs`, referenced everywhere else.
 
 ## 2026-03-28 – Remove journal.md
 
-- **Who**: Hekate, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: One-time development notes from the Rust rewrite, never updated after initial session. Overlapped with memory system and git history.
 - **Tradeoffs**: Historical context lost from the file, but the information is preserved in git history and the memory system.
 - **How**: Deleted. Useful technical learnings migrated to persistent memory.
 
 ## 2026-03-27 – OVERLAY layer instead of TOP
 
-- **Who**: Hekate, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Waybar occupies the TOP layer. The power menu must appear above it.
 - **Tradeoffs**: OVERLAY is the highest layer — nothing can render above moonset while it's open. This is intentional for a session power menu.
 - **How**: `setup_layer_shell` uses `gtk4_layer_shell::Layer::Overlay` for the panel window.
 
 ## 2026-03-27 – Lock without confirmation
 
-- **Who**: Hekate, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Lock is immediately reversible (just unlock). All other actions (logout, hibernate, reboot, shutdown) are destructive or disruptive.
 - **Tradeoffs**: One less click for the most common action. Risk of accidental lock is negligible since unlocking is trivial.
 - **How**: `ActionDef.needs_confirm = false` for lock; all others require inline confirmation.
 
 ## 2026-03-27 – Niri-specific logout via `niri msg action quit`
 
-- **Who**: Hekate, Dom
+- **Who**: ClaudeCode, Dom
 - **Why**: Moonarch is built exclusively for the Niri compositor. Generic Wayland logout mechanisms don't exist — each compositor has its own.
 - **Tradeoffs**: Hard dependency on Niri. If the compositor changes, `power::logout()` must be updated.
 - **How**: `Command::new("/usr/bin/niri").args(["msg", "action", "quit"])`.

build.rs

@@ -1,5 +1,5 @@
 // ABOUTME: Build script for compiling GResource bundle.
-// ABOUTME: Bundles style.css, wallpaper.jpg, and default-avatar.svg into the binary.
+// ABOUTME: Bundles style.css and default-avatar.svg into the binary.
 
 fn main() {
     glib_build_tools::compile_resources(

resources/resources.gresource.xml

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

src/panel.rs

@@ -103,6 +103,10 @@ pub fn load_background_texture(bg_path: Option<&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 moongreet/src/greeter.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;
@@ -288,6 +292,7 @@ pub fn create_panel_window(texture: Option<&gdk::Texture>, blur_radius: Option<f
             &confirm_area,
             &confirm_box,
             &error_label,
+            &button_box,
         );
         button_box.append(&button);
     }
@@ -371,6 +376,7 @@ fn create_action_button(
     confirm_area: &gtk::Box,
     confirm_box: &Rc<RefCell<Option<gtk::Box>>>,
     error_label: &gtk::Label,
+    button_box: &gtk::Box,
 ) -> gtk::Button {
     let button_content = gtk::Box::new(gtk::Orientation::Vertical, 4);
     button_content.set_halign(gtk::Align::Center);
@@ -400,6 +406,8 @@ fn create_action_button(
         confirm_box,
         #[weak]
         error_label,
+        #[weak]
+        button_box,
         move |_| {
             on_action_clicked(
                 &action_def,
@@ -408,6 +416,7 @@ fn create_action_button(
                 &confirm_area,
                 &confirm_box,
                 &error_label,
+                &button_box,
             );
         }
     ));
@@ -430,6 +439,7 @@ fn on_action_clicked(
     confirm_area: &gtk::Box,
     confirm_box: &Rc<RefCell<Option<gtk::Box>>>,
     error_label: &gtk::Label,
+    button_box: &gtk::Box,
 ) {
     dismiss_confirm(confirm_area, confirm_box);
     error_label.set_visible(false);
@@ -439,7 +449,7 @@ fn on_action_clicked(
         return;
     }
 
-    show_confirm(action_def, strings, app, confirm_area, confirm_box, error_label);
+    show_confirm(action_def, strings, app, confirm_area, confirm_box, error_label, button_box);
 }
 
 /// Show inline confirmation below the action buttons.
@@ -450,6 +460,7 @@ fn show_confirm(
     confirm_area: &gtk::Box,
     confirm_box: &Rc<RefCell<Option<gtk::Box>>>,
     error_label: &gtk::Label,
+    button_box: &gtk::Box,
 ) {
     let new_box = gtk::Box::new(gtk::Orientation::Vertical, 8);
     new_box.set_halign(gtk::Align::Center);
@@ -497,8 +508,13 @@ fn show_confirm(
         confirm_area,
         #[strong]
         confirm_box,
+        #[weak]
+        button_box,
         move |_| {
             dismiss_confirm(&confirm_area, &confirm_box);
+            if let Some(first) = button_box.first_child() {
+                first.grab_focus();
+            }
         }
     ));
     button_row.append(&no_btn);

src/power.rs

@@ -40,7 +40,9 @@ fn run_command(action: &'static str, program: &str, args: &[&str]) -> Result<(),
     log::debug!("Power action: {action} ({program} {args:?})");
     let mut child = Command::new(program)
         .args(args)
-        .stdout(Stdio::piped())
+        // stdout is discarded — piping without draining would deadlock if a
+        // command ever wrote more than one OS pipe buffer before wait() returned.
+        .stdout(Stdio::null())
         .stderr(Stdio::piped())
         .spawn()
         .map_err(|e| PowerError::CommandFailed {
@@ -107,7 +109,7 @@ pub fn lock() -> Result<(), PowerError> {
     Command::new("/usr/bin/moonlock")
         .stdin(Stdio::null())
         .stdout(Stdio::null())
-        .stderr(Stdio::null())
+        .stderr(Stdio::inherit())
         .spawn()
         .map_err(|e| PowerError::CommandFailed {
             action: "lock",