feat(nixpak): sandbox six desktop apps (#497)

* feat(nixpak): sandbox six desktop apps * chore(nixpak): trim OBS plugin set * fix(nixpak): enable OBS on aarch64 * fix(nixpak): let imv read the full home directory * fix(home): drop redundant freerdp package * fix(nixpak): grant OBS access to V4L2 camera devices * fix(nixpak): expose V4L2 sysfs to OBS * fix(nixpak): expose NVIDIA encode library to OBS * docs(nixpak): record OBS interactive validation * docs(nixpak): record OBS RTMP validation * fix(nixpak): run MuseScore via XWayland and PulseAudio * docs(nixpak): explain app sandboxing rationale * fix(nixpak): route MuseScore ALSA through PipeWire
2026-11-13 12:13:36 +01:00 · 2026-11-01 01:24:47 -05:00
1 parent 5e5ceae108
commit c277c81cd6
@@ -3,13 +3,23 @@
 Deployed and interactively validated on the Linux desktop host (2026-10-31). Policy and limits:
 [SECURITY.md](../SECURITY.md).

+## Why these apps are sandboxed
+
+The packaging scope is driven by blast radius and input exposure, not by treating the applications
+as malicious. These apps parse complex local or remote content, load third-party plugins (OBS), or
+hold powerful network/session privileges (Remmina); a parser, plugin or session compromise would
+otherwise inherit the user's home, session D-Bus, devices and network. Each wrapper grants only the
+ports, devices, sockets, writable directories and desktop portals needed by that app's documented
+workflow.
+
 ## Shared boundaries

 - Cleared environment; filtered session D-Bus; private `/dev/shm`; per-app `/tmp`. Chromium-family
  browsers share an app-specific `/tmp` so external URLs reuse one browser instance.
 - Read-only `/nix/store`; GPU and display; fonts and themes; LAN and Internet.
 - Portals for file chooser, URI opening, notifications, input methods and document exports.
- No whole host home, system D-Bus, SSH agent, USB/serial, raw camera or raw PipeWire socket.
+- No whole host home, system D-Bus, SSH agent, USB/serial or raw camera. Raw PipeWire is granted
+  only to MuseScore for its ALSA-via-PipeWire audio path; see [Limits](#limits).
 - Host loopback only for Firefox/Chromium; all other apps use pasta-isolated loopback. Chromium is
  an intentional development exception. Brave Origin and Edge are backup browsers and receive no
  media grants.
@@ -19,21 +29,27 @@ Deployed and interactively validated on the Linux desktop host (2026-10-31). Pol
 `Media` means audio playback, microphone, Camera and ScreenCast portals. Writable paths are listed
 explicitly; other files use the document portal. Every app also has private writable state.

-| App          | Network       | Writable paths                                                                        | Grants                                                                                       |
-| ------------ | ------------- | ------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------- |
-| Firefox      | Host loopback | `~/.mozilla`, personal files, Trash, Firefox artwork                                  | Audio, browserpass, MPRIS, idle; camera/screen sharing intentionally unavailable             |
-| Chromium     | Host loopback | `~/.config/chromium`, personal files                                                  | Media, browserpass, MPRIS, idle, v12 Secret                                                  |
-| Chrome       | Isolated      | `~/.config/google-chrome`, Downloads                                                  | Media, browserpass, MPRIS, idle, v12 Secret                                                  |
-| Brave Origin | Isolated      | `~/.config/BraveSoftware/Brave-Origin`, Downloads                                     | v12 Secret                                                                                   |
-| Edge         | Isolated      | `~/.config/microsoft-edge`, Downloads                                                 | v12 Secret                                                                                   |
-| QQ           | Isolated      | Personal files, private app state                                                     | Media, notifications, tray, MPRIS, idle, accessibility                                       |
-| Telegram     | Isolated      | Personal files, private app state                                                     | Media, notifications, tray, MPRIS, idle, accessibility, Ayatana indicators                   |
-| Zoom         | Isolated      | `~/.zoom`, `zoomus.conf`, `zoom.conf`, Downloads, `Documents/Zoom`, private app state | Media, X11/XWayland, FHS, SNI tray, idle, `/dev/video0-1`, read-only `/sys/class/drm`        |
-| WeChat       | Isolated      | Documents, Downloads, app-scoped `wechat` data, private app state                     | Media, Wayland, X11 fallback, SNI tray, file chooser portal                                  |
-| Foliate      | None          | Documents/Downloads/Pictures read-only, app-scoped state                              | File chooser, OpenURI, notifications, IME, accessibility                                     |
-| Krita        | None          | Documents/Downloads/Pictures writable, app-scoped state                               | File chooser, OpenURI, print, inhibit, notifications, IME, accessibility                     |
-| Bambu Studio | Isolated      | Documents/Downloads/Pictures writable, app-scoped state                               | X11/XWayland, PulseAudio, cloud/LAN network, file chooser, notifications, IME, accessibility |
-| OrcaSlicer   | Isolated      | Documents/Downloads/Pictures writable, app-scoped state                               | X11/XWayland, cloud/LAN network, file chooser, notifications, IME, accessibility             |
+| App          | Network       | Writable paths                                                                        | Grants                                                                                         |
+| ------------ | ------------- | ------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- |
+| Firefox      | Host loopback | `~/.mozilla`, personal files, Trash, Firefox artwork                                  | Audio, browserpass, MPRIS, idle; camera/screen sharing intentionally unavailable               |
+| Chromium     | Host loopback | `~/.config/chromium`, personal files                                                  | Media, browserpass, MPRIS, idle, v12 Secret                                                    |
+| Chrome       | Isolated      | `~/.config/google-chrome`, Downloads                                                  | Media, browserpass, MPRIS, idle, v12 Secret                                                    |
+| Brave Origin | Isolated      | `~/.config/BraveSoftware/Brave-Origin`, Downloads                                     | v12 Secret                                                                                     |
+| Edge         | Isolated      | `~/.config/microsoft-edge`, Downloads                                                 | v12 Secret                                                                                     |
+| QQ           | Isolated      | Personal files, private app state                                                     | Media, notifications, tray, MPRIS, idle, accessibility                                         |
+| Telegram     | Isolated      | Personal files, private app state                                                     | Media, notifications, tray, MPRIS, idle, accessibility, Ayatana indicators                     |
+| Zoom         | Isolated      | `~/.zoom`, `zoomus.conf`, `zoom.conf`, Downloads, `Documents/Zoom`, private app state | Media, X11/XWayland, FHS, SNI tray, idle, `/dev/video0-1`, read-only `/sys/class/drm`          |
+| WeChat       | Isolated      | Documents, Downloads, app-scoped `wechat` data, private app state                     | Media, Wayland, X11 fallback, SNI tray, file chooser portal                                    |
+| Foliate      | None          | Documents/Downloads/Pictures read-only, app-scoped state                              | File chooser, OpenURI, notifications, IME, accessibility                                       |
+| Krita        | None          | Documents/Downloads/Pictures writable, app-scoped state                               | File chooser, OpenURI, print, inhibit, notifications, IME, accessibility                       |
+| Bambu Studio | Isolated      | Documents/Downloads/Pictures writable, app-scoped state                               | X11/XWayland, PulseAudio, cloud/LAN network, file chooser, notifications, IME, accessibility   |
+| OrcaSlicer   | Isolated      | Documents/Downloads/Pictures writable, app-scoped state                               | X11/XWayland, cloud/LAN network, file chooser, notifications, IME, accessibility               |
+| Remmina      | Isolated      | `~/.config/remmina`, `~/.local/share/remmina`, `~/.remmina`, Downloads                | PulseAudio, SSH agent, file chooser, OpenURI, notifications, IME, accessibility                |
+| OBS Studio   | Isolated      | `~/.config/obs-studio`, Videos/Pictures/Downloads                                     | ScreenCast, V4L2 camera (`/dev/video0-1`), PulseAudio, tray, notifications, IME, accessibility |
+| Blender      | Isolated      | `~/.config/blender`, Documents/Downloads/Pictures/Videos                              | X11/XWayland, PulseAudio, notifications, IME, accessibility                                    |
+| MuseScore    | Isolated      | `~/.config/MuseScore`, `~/.local/share/MuseScore`, Documents/Downloads/Music/Pictures | ALSA via PipeWire, ALSA sequencer, X11/XWayland, print, notifications, IME, accessibility      |
+| mpv          | Isolated      | `~/.config/mpv`, `~/.cache/mpv`, `~/.local/state/mpv`; media dirs read-only           | MPRIS, file chooser, OpenURI                                                                   |
+| imv          | None          | `$HOME` read-only                                                                     | File chooser, OpenURI                                                                          |

 All browsers get read-only NSS certificates, printing, native notifications and accessibility.

@@ -65,6 +81,18 @@ All browsers get read-only NSS certificates, printing, native notifications and
 - Bambu Studio's nixpkgs build omits the `device_page` frontend bundle, so filament management is
  unavailable. Its MakerWorld sidebar entry also requires the upstream `firstguide.finish = "true"`
  workaround; the startup splash may render black under XWayland.
+- Remmina's SSH Tunnel support receives a read-only SSH agent socket and SSH client config. A
+  compromised Remmina can use the agent to sign or decrypt while the agent is running.
+- OBS, Blender, MuseScore and mpv use pasta-isolated networking. Host loopback services are not
+  reachable unless the app is changed to a host-loopback exception.
+- MuseScore receives the raw PipeWire socket so its ALSA driver can use the host `pcm.!default`
+  PipeWire plugin. PipeWire is a general media graph, so this is broader than a single audio stream:
+  a compromised MuseScore could enumerate other user-visible PipeWire media nodes. The alternative,
+  direct `/dev/snd`, confines the media graph but bypasses PipeWire device selection, per-app volume
+  and mixing.
+- OBS on Linux defaults its recording path to `$HOME`. The sandbox intentionally binds only the
+  declared home subdirectories, so recording output must target `Videos`, `Pictures` or `Downloads`;
+  a file written to the home root exists only in the sandbox's transient mount namespace.

 ## Validation

@@ -72,6 +100,12 @@ All browsers get read-only NSS certificates, printing, native notifications and
 - Interactive validation passed for Firefox, Chrome, Chromium, Brave Origin, Edge, QQ, Telegram,
  Zoom, Bambu Studio and OrcaSlicer. Chromium's host-loopback/personal-file exception and the
  Brave/Edge no-media policy are intentional.
+- OBS Studio passed interactive validation for PipeWire screen capture, V4L2 camera capture,
+  desktop/microphone audio, local NVENC H.264 MP4 recording and local RTMP streaming. External
+  provider authentication and browser sources remain unvalidated.
+- Remmina, Blender, mpv and imv build and pass the policy suite; interactive validation is still
+  pending. MuseScore passed launch, XWayland and ALSA-to-PipeWire routing checks; audible playback
+  and user workflows still need confirmation.
 - Chromium smoke test passed: renderer sandbox, environment clearing, bind scope, disposable-profile
  persistence and loopback policy.
 - WeChat uses the native nixpkgs-patched package with nixpak as the only bwrap layer. Build/policy
@@ -0,0 +1,54 @@
+{
+  lib,
+  blender,
+  mkNixPak,
+  buildEnv,
+  makeDesktopItem,
+  runCommandLocal,
+  ...
+}:
+let
+  appId = "org.blender.Blender";
+  wrapped = mkNixPak {
+    config = {
+      imports = [ ./modules/blender-policy.nix ];
+      app = {
+        package = blender;
+        binPath = "bin/blender";
+      };
+      flatpak = { inherit appId; };
+    };
+  };
+  exe = lib.getExe wrapped.config.script;
+  assets = runCommandLocal "blender-desktop-assets" { } ''
+    mkdir -p $out/share
+    ln -s ${blender}/share/icons $out/share/icons
+  '';
+in
+buildEnv {
+  inherit (wrapped.config.script) name passthru;
+  meta = wrapped.config.script.meta // {
+    mainProgram = "blender";
+  };
+  paths = [
+    wrapped.config.script
+    assets
+    (makeDesktopItem {
+      name = "blender";
+      desktopName = "Blender";
+      genericName = "3D Creation Suite";
+      comment = "3D modeling, animation and rendering";
+      exec = "${exe} %f";
+      icon = "blender";
+      terminal = false;
+      startupNotify = true;
+      startupWMClass = "Blender";
+      categories = [
+        "Graphics"
+        "3DGraphics"
+      ];
+      mimeTypes = [ "application/x-blender" ];
+      extraConfig.X-Flatpak = appId;
+    })
+  ];
+}
@@ -3,6 +3,7 @@
  pkgs-master,
  pkgs-patched,
  pkgs-stable,
+  pkgs-blender,
  nixpak,
  ...
 }:
@@ -32,6 +33,12 @@ in
        bambu-studio = wrapper pkgs-master ./bambu-studio.nix;
        orca-slicer = wrapper pkgs-master ./orca-slicer.nix;
        zoom = wrapper super ./zoom.nix;
+        remmina = wrapper super ./remmina.nix;
+        obs-studio = wrapper super ./obs-studio.nix;
+        blender = wrapper pkgs-blender ./blender.nix;
+        musescore = wrapper pkgs-stable ./musescore.nix;
+        mpv = wrapper super ./mpv.nix;
+        imv = wrapper super ./imv.nix;
        wechat = wrapper pkgs-patched ./wechat.nix;
      };
    })
@@ -0,0 +1,71 @@
+{
+  lib,
+  pkgs,
+  imv,
+  mkNixPak,
+  buildEnv,
+  makeDesktopItem,
+  ...
+}:
+let
+  appId = "com.github.exec64.imv";
+  wrapped = mkNixPak {
+    config = {
+      imports = [ ./modules/image-viewer-policy.nix ];
+      app = {
+        package = imv;
+        binPath = "bin/imv";
+      };
+      flatpak = { inherit appId; };
+    };
+  };
+  exe = lib.getExe wrapped.config.script;
+  # Match the upstream imv-dir helper: one file opens its containing directory;
+  # multiple arguments are passed through to imv unchanged.
+  imvDir = pkgs.writeShellScript "imv-dir" ''
+    if [ "$#" -ne 1 ]; then
+      exec ${exe} "$@"
+    fi
+    exec ${exe} -n "$1" "$(${pkgs.coreutils}/bin/dirname "$1")"
+  '';
+  desktopItem =
+    name: desktopName: exec:
+    makeDesktopItem {
+      inherit name desktopName exec;
+      genericName = "Image Viewer";
+      comment = "View images";
+      icon = "multimedia-photo-viewer";
+      terminal = false;
+      startupNotify = true;
+      startupWMClass = "imv";
+      categories = [
+        "Graphics"
+        "2DGraphics"
+        "Viewer"
+      ];
+      mimeTypes = [
+        "image/avif"
+        "image/bmp"
+        "image/gif"
+        "image/heif"
+        "image/jpeg"
+        "image/jxl"
+        "image/png"
+        "image/svg+xml"
+        "image/tiff"
+        "image/webp"
+      ];
+      extraConfig.X-Flatpak = appId;
+    };
+in
+buildEnv {
+  inherit (wrapped.config.script) name passthru;
+  meta = wrapped.config.script.meta // {
+    mainProgram = "imv";
+  };
+  paths = [
+    wrapped.config.script
+    (desktopItem "imv" "imv" "${exe} %F")
+    (desktopItem "imv-dir" "imv-dir" "${imvDir} %F")
+  ];
+}
@@ -0,0 +1,40 @@
+# Blender needs GPU access, audio for the sequencer and network for extensions;
+# user files are shared through common document directories and the portal.
+{
+  sloth,
+  ...
+}:
+{
+  imports = [
+    ./desktop-base.nix
+    ./network.nix
+  ];
+  pasta.mode = "isolate";
+  portalGroups = {
+    fileChooser = true;
+    openUri = true;
+    notifications = true;
+    inputMethod = true;
+  };
+  desktopIntegration = {
+    notifications = true;
+    accessibility = true;
+  };
+  bubblewrap = {
+    sockets = {
+      x11 = true;
+      pulse = true;
+    };
+    bind.rw = [
+      (sloth.mkdir (sloth.concat' sloth.homeDir "/.config/blender"))
+      sloth.xdgDocumentsDir
+      sloth.xdgDownloadDir
+      sloth.xdgPicturesDir
+      sloth.xdgVideosDir
+    ];
+    env = {
+      DISPLAY = sloth.envOr "DISPLAY" "";
+      XAUTHORITY = sloth.envOr "XAUTHORITY" (sloth.concat' sloth.homeDir "/.Xauthority");
+    };
+  };
+}
@@ -0,0 +1,17 @@
+# Minimal local image viewer. The whole home is read-only so images can be
+# opened from any user directory; network, audio and devices stay unavailable.
+{
+  sloth,
+  ...
+}:
+{
+  imports = [ ./desktop-base.nix ];
+  portalGroups = {
+    fileChooser = true;
+    openUri = true;
+  };
+  bubblewrap = {
+    sockets.pulse = false;
+    bind.ro = [ sloth.homeDir ];
+  };
+}
@@ -0,0 +1,34 @@
+# mpv policy: media directories are read-only, playback state and user config
+# remain writable, and MPRIS is the only desktop service it owns.
+{
+  sloth,
+  ...
+}:
+{
+  imports = [
+    ./desktop-base.nix
+    ./network.nix
+  ];
+  pasta.mode = "isolate";
+  portalGroups = {
+    fileChooser = true;
+    openUri = true;
+  };
+  desktopIntegration.mpris = true;
+  bubblewrap = {
+    sockets.pulse = true;
+    bind.rw = [
+      (sloth.mkdir (sloth.concat' sloth.homeDir "/.config/mpv"))
+      (sloth.mkdir (sloth.concat' sloth.homeDir "/.cache/mpv"))
+      (sloth.mkdir (sloth.concat' sloth.homeDir "/.local/state/mpv"))
+    ];
+    bind.ro = [
+      sloth.xdgDocumentsDir
+      sloth.xdgDownloadDir
+      sloth.xdgMusicDir
+      sloth.xdgPicturesDir
+      sloth.xdgVideosDir
+      (sloth.concat' sloth.homeDir "/.config/yt-dlp")
+    ];
+  };
+}
@@ -0,0 +1,58 @@
+# MuseScore policy: scores and exports use common user directories. Audio uses
+# ALSA via the host PipeWire plugin, MIDI uses the ALSA sequencer, and the UI
+# runs through XWayland.
+{
+  lib,
+  sloth,
+  ...
+}:
+{
+  imports = [
+    ./desktop-base.nix
+    ./network.nix
+  ];
+  pasta.mode = "isolate";
+  portalGroups = {
+    fileChooser = true;
+    openUri = true;
+    notifications = true;
+    print = true;
+    inputMethod = true;
+  };
+  desktopIntegration = {
+    notifications = true;
+    accessibility = true;
+  };
+  bubblewrap = {
+    sockets = {
+      # MuseScore 4's nixpkgs launcher selects Qt's XCB backend. Niri provides
+      # that through XWayland, so expose the X11 socket and credentials.
+      x11 = true;
+      # MuseScore speaks ALSA; the host ALSA configuration forwards its
+      # default PCM to PipeWire, so expose the PipeWire socket for audio.
+      pulse = lib.mkForce false;
+      pipewire = lib.mkForce true;
+    };
+    bind.rw = [
+      (sloth.mkdir (sloth.concat' sloth.homeDir "/.config/MuseScore"))
+      (sloth.mkdir (sloth.concat' sloth.homeDir "/.local/share/MuseScore"))
+      sloth.xdgDocumentsDir
+      sloth.xdgDownloadDir
+      sloth.xdgMusicDir
+      sloth.xdgPicturesDir
+    ];
+    # Use the host's ALSA configuration, which routes the default PCM
+    # through PipeWire. Only the sequencer node is needed for MIDI.
+    bind.ro = [
+      "/etc/alsa"
+      "/etc/static/alsa"
+    ];
+    bind.dev = [ "/dev/snd/seq" ];
+    env = {
+      DISPLAY = sloth.envOr "DISPLAY" "";
+      XAUTHORITY = sloth.envOr "XAUTHORITY" (sloth.concat' sloth.homeDir "/.Xauthority");
+      QT_QPA_PLATFORM = "xcb";
+      MUSESCORE_FORCE_ALSA = "1";
+    };
+  };
+}
@@ -0,0 +1,60 @@
+# OBS capture policy: screen capture stays on the XDG portal, audio goes
+# through PulseAudio/PipeWire-Pulse, and network access is pasta-isolated.
+# OBS's V4L2 source opens camera device nodes directly instead of using the
+# Camera portal, so grant the same raw video devices as Zoom.
+{
+  sloth,
+  ...
+}:
+{
+  imports = [
+    ./desktop-base.nix
+    ./network.nix
+  ];
+  pasta.mode = "isolate";
+  portalGroups = {
+    fileChooser = true;
+    openUri = true;
+    notifications = true;
+    screenCast = true;
+    camera = true;
+    inhibit = true;
+    inputMethod = true;
+  };
+  desktopIntegration = {
+    notifications = true;
+    tray = true;
+    accessibility = true;
+  };
+  bubblewrap = {
+    sockets = {
+      x11 = true;
+      pulse = true;
+    };
+    bind.rw = [
+      (sloth.mkdir (sloth.concat' sloth.homeDir "/.config/obs-studio"))
+      sloth.xdgVideosDir
+      sloth.xdgPicturesDir
+      sloth.xdgDownloadDir
+    ];
+    # OBS enumerates DRM connectors when building its encoder list, and its
+    # V4L2 source discovers cameras by reading /sys/class/video4linux before
+    # opening the corresponding /dev/video* nodes.
+    bind.ro = [
+      "/sys/class/drm"
+      "/sys/class/video4linux"
+    ];
+    bind.dev = [
+      "/dev/video0"
+      "/dev/video1"
+    ];
+    env = {
+      DISPLAY = sloth.envOr "DISPLAY" "";
+      XAUTHORITY = sloth.envOr "XAUTHORITY" (sloth.concat' sloth.homeDir "/.Xauthority");
+      # OBS's NVENC plugin dlopen()s libnvidia-encode.so.1 by soname after
+      # startup. Nixpak exposes the host driver under /run/opengl-driver but
+      # clears the host environment, so add it to the loader search path.
+      LD_LIBRARY_PATH = "/run/opengl-driver/lib";
+    };
+  };
+}
@@ -0,0 +1,48 @@
+# Shared policy for graphical remote-desktop clients. No raw camera, video or
+# PipeWire access; SSH tunnels use the user's agent socket explicitly.
+{
+  config,
+  lib,
+  sloth,
+  ...
+}:
+let
+  cfg = config.remoteDesktop;
+in
+{
+  imports = [
+    ./desktop-base.nix
+    ./network.nix
+  ];
+  options.remoteDesktop.sshAgent = lib.mkEnableOption "the user's SSH agent and SSH client config";
+  config = {
+    pasta.mode = "isolate";
+    portalGroups = {
+      fileChooser = true;
+      openUri = true;
+      notifications = true;
+      inputMethod = true;
+    };
+    desktopIntegration = {
+      notifications = true;
+      accessibility = true;
+    };
+    bubblewrap = {
+      sockets.pulse = true;
+      bind.rw = [
+        (sloth.mkdir (sloth.concat' sloth.homeDir "/.config/remmina"))
+        (sloth.mkdir (sloth.concat' sloth.homeDir "/.local/share/remmina"))
+        (sloth.mkdir (sloth.concat' sloth.homeDir "/.remmina"))
+        sloth.xdgDownloadDir
+      ];
+      bind.ro = lib.optionals cfg.sshAgent [
+        (sloth.concat' sloth.homeDir "/.ssh/config")
+        (sloth.concat' sloth.homeDir "/.ssh/known_hosts")
+        (sloth.concat' sloth.runtimeDir "/ssh-agent")
+      ];
+      env = lib.optionalAttrs cfg.sshAgent {
+        SSH_AUTH_SOCK = sloth.concat' sloth.runtimeDir "/ssh-agent";
+      };
+    };
+  };
+}
@@ -0,0 +1,64 @@
+{
+  lib,
+  mpv,
+  mpvScripts,
+  mkNixPak,
+  buildEnv,
+  makeDesktopItem,
+  ...
+}:
+let
+  appId = "io.mpv.Mpv";
+  package = mpv.override { scripts = [ mpvScripts.mpris ]; };
+  wrapped = mkNixPak {
+    config = {
+      imports = [ ./modules/mpv-policy.nix ];
+      app = {
+        inherit package;
+        binPath = "bin/mpv";
+      };
+      flatpak = { inherit appId; };
+    };
+  };
+  exe = lib.getExe wrapped.config.script;
+in
+buildEnv {
+  inherit (wrapped.config.script) name passthru;
+  meta = wrapped.config.script.meta // {
+    mainProgram = "mpv";
+  };
+  paths = [
+    wrapped.config.script
+    (makeDesktopItem {
+      name = "mpv";
+      desktopName = "mpv Media Player";
+      genericName = "Media Player";
+      comment = "Play audio and video files";
+      exec = "${exe} --player-operation-mode=pseudo-gui -- %U";
+      icon = "mpv";
+      terminal = false;
+      startupNotify = true;
+      startupWMClass = "mpv";
+      categories = [
+        "AudioVideo"
+        "Audio"
+        "Video"
+        "Player"
+      ];
+      mimeTypes = [
+        "application/ogg"
+        "application/x-matroska"
+        "audio/flac"
+        "audio/mpeg"
+        "audio/ogg"
+        "audio/wav"
+        "video/mp4"
+        "video/quicktime"
+        "video/webm"
+        "video/x-matroska"
+        "video/x-msvideo"
+      ];
+      extraConfig.X-Flatpak = appId;
+    })
+  ];
+}
@@ -0,0 +1,64 @@
+{
+  lib,
+  musescore,
+  mkNixPak,
+  buildEnv,
+  makeDesktopItem,
+  runCommandLocal,
+  ...
+}:
+let
+  appId = "org.musescore.MuseScore";
+  wrapped = mkNixPak {
+    config = {
+      imports = [ ./modules/musescore-policy.nix ];
+      app = {
+        package = musescore;
+        binPath = "bin/mscore";
+      };
+      flatpak = { inherit appId; };
+    };
+  };
+  exe = lib.getExe wrapped.config.script;
+  assets = runCommandLocal "musescore-desktop-assets" { } ''
+    mkdir -p $out/share
+    ln -s ${musescore}/share/icons $out/share/icons
+  '';
+in
+buildEnv {
+  inherit (wrapped.config.script) name passthru;
+  meta = wrapped.config.script.meta // {
+    mainProgram = "mscore";
+  };
+  paths = [
+    wrapped.config.script
+    assets
+    (makeDesktopItem {
+      name = appId;
+      desktopName = "MuseScore Studio";
+      genericName = "Music Notation";
+      comment = "Create, play and print sheet music";
+      exec = "${exe} %U";
+      icon = "mscore";
+      terminal = false;
+      startupNotify = true;
+      startupWMClass = "MuseScore4";
+      categories = [
+        "AudioVideo"
+        "Audio"
+        "Graphics"
+        "Midi"
+        "Music"
+      ];
+      mimeTypes = [
+        "application/x-musescore"
+        "application/x-musescore+xml"
+        "application/vnd.recordare.musicxml"
+        "application/vnd.recordare.musicxml+xml"
+        "audio/midi"
+        "x-scheme-handler/musescore"
+      ];
+      extraConfig.X-Flatpak = appId;
+    })
+  ];
+}
@@ -0,0 +1,70 @@
+{
+  lib,
+  obs-studio,
+  obs-studio-plugins,
+  wrapOBS,
+  mkNixPak,
+  buildEnv,
+  makeDesktopItem,
+  runCommandLocal,
+  ...
+}:
+let
+  appId = "com.obsproject.Studio";
+  package = wrapOBS.override { inherit obs-studio; } {
+    plugins = with obs-studio-plugins; [
+      # Wayland screen-capture fallback, per-application audio, and game capture.
+      wlrobs
+      obs-pipewire-audio-capture
+      obs-vkcapture
+      # Widely used scene, overlay and streaming plugins.
+      input-overlay
+      obs-multi-rtmp
+      obs-shaderfilter
+      obs-move-transition
+      obs-backgroundremoval
+      advanced-scene-switcher
+    ];
+  };
+  wrapped = mkNixPak {
+    config = {
+      imports = [ ./modules/obs-policy.nix ];
+      app = {
+        inherit package;
+        binPath = "bin/obs";
+      };
+      flatpak = { inherit appId; };
+    };
+  };
+  exe = lib.getExe wrapped.config.script;
+  assets = runCommandLocal "obs-studio-desktop-assets" { } ''
+    mkdir -p $out/share
+    ln -s ${package}/share/icons $out/share/icons
+  '';
+in
+buildEnv {
+  inherit (wrapped.config.script) name passthru;
+  meta = wrapped.config.script.meta // {
+    mainProgram = "obs";
+  };
+  paths = [
+    wrapped.config.script
+    assets
+    (makeDesktopItem {
+      name = appId;
+      desktopName = "OBS Studio";
+      genericName = "Screen Recorder";
+      comment = "Record and stream the desktop";
+      exec = "${exe} %U";
+      icon = appId;
+      terminal = false;
+      startupNotify = true;
+      startupWMClass = "obs";
+      categories = [
+        "AudioVideo"
+        "Recorder"
+      ];
+      extraConfig.X-Flatpak = appId;
+    })
+  ];
+}
@@ -0,0 +1,63 @@
+{
+  lib,
+  remmina,
+  mkNixPak,
+  buildEnv,
+  makeDesktopItem,
+  runCommandLocal,
+  ...
+}:
+let
+  appId = "org.remmina.Remmina";
+  wrapped = mkNixPak {
+    config = {
+      imports = [ ./modules/remote-desktop-policy.nix ];
+      app = {
+        package = remmina;
+        binPath = "bin/remmina";
+      };
+      flatpak = { inherit appId; };
+      # Preserve the SSH Tunnel tab used for localhost VNC access.
+      remoteDesktop.sshAgent = true;
+    };
+  };
+  exe = lib.getExe wrapped.config.script;
+  assets = runCommandLocal "remmina-desktop-assets" { } ''
+    mkdir -p $out/share
+    ln -s ${remmina}/share/icons $out/share/icons
+  '';
+in
+buildEnv {
+  inherit (wrapped.config.script) name passthru;
+  meta = wrapped.config.script.meta // {
+    mainProgram = "remmina";
+  };
+  paths = [
+    wrapped.config.script
+    assets
+    (makeDesktopItem {
+      name = appId;
+      desktopName = "Remmina";
+      genericName = "Remote Desktop Client";
+      comment = "Connect to RDP, VNC, SPICE and SSH sessions";
+      exec = "${exe} %U";
+      icon = appId;
+      terminal = false;
+      startupNotify = true;
+      startupWMClass = appId;
+      categories = [
+        "GTK"
+        "Network"
+      ];
+      mimeTypes = [
+        "application/x-remmina"
+        "x-scheme-handler/rdp"
+        "x-scheme-handler/spice"
+        "x-scheme-handler/vnc"
+        "x-scheme-handler/ssh"
+        "x-scheme-handler/remmina"
+      ];
+      extraConfig.X-Flatpak = appId;
+    })
+  ];
+}
@@ -72,11 +72,11 @@ let
      throw "unknown network mode for ${app.flatpak.appId}: ${mode}";

  mediaCheck =
-    app: expected:
+    app: expected: allowPipewire:
    if expected then
      app.portalGroups.camera && app.portalGroups.screenCast
    else
-      !app.bubblewrap.sockets.pipewire
+      (!app.bubblewrap.sockets.pipewire || allowPipewire)
      && !app.portalGroups.camera
      && !app.portalGroups.screenCast
      && !(hasDbusFragment app "org.freedesktop.portal.Camera")
@@ -113,7 +113,7 @@ let
      checks = {
        "${name}/clearEnv" = app.bubblewrap.clearEnv;
        "${name}/dbus" = app.dbus.enable;
-        "${name}/noRawPipewire" = !app.bubblewrap.sockets.pipewire;
+        "${name}/noRawPipewire" = !app.bubblewrap.sockets.pipewire || (spec.allowPipewire or false);
        "${name}/noForbiddenDbus" = !lib.any forbiddenDbus app.dbus.args;
        "${name}/noBroadKeyring" =
          !lib.any (argument: argument == "--talk=org.freedesktop.secrets") app.dbus.args;
@@ -123,7 +123,7 @@ let
        "${name}/privateTmp" = hasPrivateTmp app;
        "${name}/network" = networkCheck app spec.network;
        "${name}/x11" = app.bubblewrap.sockets.x11 == (spec.x11 or false);
-        "${name}/media" = mediaCheck app (spec.media or false);
+        "${name}/media" = mediaCheck app (spec.media or false) (spec.allowPipewire or false);
        "${name}/pulse" = app.bubblewrap.sockets.pulse == (spec.pulse or (spec.media or false));
        "${name}/mpris" = app.desktopIntegration.mpris == (spec.mpris or false);
        "${name}/notifications" = app.desktopIntegration.notifications == (spec.notifications or true);
@@ -0,0 +1,21 @@
+{
+  load,
+  mkAppPolicy,
+  ...
+}:
+let
+  app = load "blender";
+in
+mkAppPolicy "blender" {
+  network = "pasta";
+  media = false;
+  pulse = true;
+  x11 = true;
+  notifications = true;
+  extraChecks = {
+    fileChooser = app.portalGroups.fileChooser;
+    openUri = app.portalGroups.openUri;
+    inputMethod = app.portalGroups.inputMethod;
+    accessibility = app.desktopIntegration.accessibility;
+  };
+}
@@ -0,0 +1,20 @@
+{
+  load,
+  mkAppPolicy,
+  ...
+}:
+let
+  app = load "imv";
+in
+mkAppPolicy "imv" {
+  network = "none";
+  media = false;
+  pulse = false;
+  x11 = false;
+  notifications = false;
+  extraChecks = {
+    fileChooser = app.portalGroups.fileChooser;
+    openUri = app.portalGroups.openUri;
+    noAudio = !app.bubblewrap.sockets.pulse;
+  };
+}
@@ -0,0 +1,20 @@
+{
+  load,
+  mkAppPolicy,
+  ...
+}:
+let
+  app = load "mpv";
+in
+mkAppPolicy "mpv" {
+  network = "pasta";
+  media = false;
+  pulse = true;
+  x11 = false;
+  mpris = true;
+  notifications = false;
+  extraChecks = {
+    fileChooser = app.portalGroups.fileChooser;
+    openUri = app.portalGroups.openUri;
+  };
+}
@@ -0,0 +1,29 @@
+{
+  load,
+  mkAppPolicy,
+  ...
+}:
+let
+  app = load "musescore";
+in
+mkAppPolicy "musescore" {
+  network = "pasta";
+  media = false;
+  pulse = false;
+  allowPipewire = true;
+  x11 = true;
+  notifications = true;
+  extraChecks = {
+    fileChooser = app.portalGroups.fileChooser;
+    print = app.portalGroups.print;
+    inputMethod = app.portalGroups.inputMethod;
+    accessibility = app.desktopIntegration.accessibility;
+    qtXcb = app.bubblewrap.env.QT_QPA_PLATFORM == "xcb";
+    alsaSequencer = builtins.elem "/dev/snd/seq" app.bubblewrap.bind.dev;
+    hostAlsaConfig =
+      builtins.elem "/etc/alsa" app.bubblewrap.bind.ro
+      && builtins.elem "/etc/static/alsa" app.bubblewrap.bind.ro;
+    pipewireAudio = app.bubblewrap.sockets.pipewire;
+    forceAlsa = app.bubblewrap.env.MUSESCORE_FORCE_ALSA == "1";
+  };
+}
@@ -0,0 +1,34 @@
+{
+  lib,
+  load,
+  mkAppPolicy,
+  ...
+}:
+let
+  app = load "obs-studio";
+in
+mkAppPolicy "obs-studio" {
+  network = "pasta";
+  media = true;
+  pulse = true;
+  x11 = true;
+  allowedVideoDevices = [
+    "/dev/video0"
+    "/dev/video1"
+  ];
+  notifications = true;
+  tray = true;
+  extraChecks = {
+    fileChooser = app.portalGroups.fileChooser;
+    screenCast = app.portalGroups.screenCast;
+    camera = app.portalGroups.camera;
+    inhibit = app.portalGroups.inhibit;
+    accessibility = app.desktopIntegration.accessibility;
+    videoDevices = lib.all (dev: lib.elem dev app.bubblewrap.bind.dev) [
+      "/dev/video0"
+      "/dev/video1"
+    ];
+    video4linuxSysfs = lib.elem "/sys/class/video4linux" app.bubblewrap.bind.ro;
+    nvencLibraryPath = app.bubblewrap.env.LD_LIBRARY_PATH == "/run/opengl-driver/lib";
+  };
+}
@@ -0,0 +1,22 @@
+{
+  load,
+  mkAppPolicy,
+  ...
+}:
+let
+  app = load "remmina";
+in
+mkAppPolicy "remmina" {
+  network = "pasta";
+  media = false;
+  pulse = true;
+  x11 = false;
+  notifications = true;
+  extraChecks = {
+    fileChooser = app.portalGroups.fileChooser;
+    openUri = app.portalGroups.openUri;
+    inputMethod = app.portalGroups.inputMethod;
+    accessibility = app.desktopIntegration.accessibility;
+    sshAgent = app.remoteDesktop.sshAgent;
+  };
+}
@@ -26,6 +26,12 @@ Nixpak wrappers are accepted in three layers:
 | Krita                  | Pass         | Interactive validation pending                                    |
 | Bambu Studio           | Pass         | Interactive pass; device_page/filament UI unavailable in nixpkgs  |
 | OrcaSlicer             | Pass         | Interactive pass; blank WebKit home page fixed                    |
+| Remmina                | Pass         | Interactive validation pending                                    |
+| OBS Studio             | Pass         | Interactive pass; NVENC recording and local RTMP streaming work   |
+| Blender                | Pass         | Interactive validation pending                                    |
+| MuseScore              | Pass         | Interactive launch pass; ALSA routed to default PipeWire sink     |
+| mpv                    | Pass         | Interactive validation pending                                    |
+| imv                    | Pass         | Interactive validation pending                                    |

 Intentional exceptions:

@@ -45,6 +51,10 @@ Known packaging limitations:
  `BambuStudio.conf`; the upstream guide writes `"1"` while the web-view code only accepts `"true"`.
 - **Bambu Studio:** the startup splash can render black under XWayland. This is cosmetic; the main
  UI renders normally.
+- **MuseScore:** uses Qt's XCB backend, so it runs through XWayland. Its ALSA driver uses the host
+  `pcm.!default` configuration, which forwards to PipeWire; this requires the raw PipeWire socket.
+  Launch and audio routing pass, but audible playback and score/print/export workflows still need
+  user confirmation.

 ## Browser smoke test

@@ -85,6 +95,18 @@ Zoom keeps its upstream FHS runtime inside the outer nixpak boundary. The nested
 shared-display trust boundary: ScreenCast portal permission does not prevent capture through the X11
 connection. Interactive login, audio, camera, screen sharing and file workflows passed.

+## OBS
+
+Interactive validation covered PipeWire screen capture, V4L2 camera capture, desktop/microphone
+audio, NVENC H.264 Hybrid MP4 recording and RTMP publishing. Streaming was tested against a
+temporary MediaMTX server on the host's LAN address; the OBS pasta namespace cannot reach host
+loopback. Bilibili or another external provider still needs a real account-specific stream key to
+validate provider authentication and CDN ingest.
+
+OBS records to the path configured under output settings. In Simple mode that is
+`SimpleOutput.FilePath`; Advanced mode uses `AdvOut.RecFilePath` and `AdvOut.FFFilePath`. These must
+point at a writable bind such as `~/Videos`, not the sandbox's transient home root.
+
 ## Commands

 ```bash