release: 0.2.1

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

.gitea/workflows/release.yml

@@ -30,8 +30,14 @@ jobs:
 
       - name: Build for Linux
         run: >-
-          sh -c "go build -v -ldflags '-s -w -X main.Version=${{ github.ref_name }}' -o bin/fortify &&
+          go build -v -ldflags '-s -w
-          sha256sum --tag -b bin/fortify > bin/fortify.sha256"
+          -X git.ophivana.moe/security/fortify/internal.Version=${{ github.ref_name }}
+          -X git.ophivana.moe/security/fortify/internal.Fsu=/usr/bin/fsu
+          -X git.ophivana.moe/security/fortify/internal.Finit=/usr/libexec/fortify/finit
+          -X main.Fmain=/usr/bin/fortify
+          -X main.Fshim=/usr/libexec/fortify/fshim'
+          -o bin/ ./... &&
+          (cd bin && sha512sum --tag -b * > sha512sums)
 
       - name: Release
         id: use-go-action

.gitea/workflows/test.yml

@@ -33,5 +33,11 @@ jobs:
 
       - name: Build for Linux
         run: >-
-          sh -c "go build -v -ldflags '-s -w -X main.Version=${{ github.ref_name }}' -o bin/fortify &&
+          go build -v -ldflags '-s -w
-          sha256sum --tag -b bin/fortify > bin/fortify.sha256"
+          -X git.ophivana.moe/security/fortify/internal.Version=${{ github.ref_name }}
+          -X git.ophivana.moe/security/fortify/internal.Fsu=/usr/bin/fsu
+          -X git.ophivana.moe/security/fortify/internal.Finit=/usr/libexec/fortify/finit
+          -X main.Fmain=/usr/bin/fortify
+          -X main.Fshim=/usr/libexec/fortify/fshim'
+          -o bin/ ./... &&
+          (cd bin && sha512sum --tag -b * > sha512sums)

README.md

@@ -2,6 +2,7 @@ Fortify
 =======
 
 [![Go Reference](https://pkg.go.dev/badge/git.ophivana.moe/security/fortify.svg)](https://pkg.go.dev/git.ophivana.moe/security/fortify)
+[![Go Report Card](https://goreportcard.com/badge/git.ophivana.moe/security/fortify)](https://goreportcard.com/report/git.ophivana.moe/security/fortify)
 
 Lets you run graphical applications as another user in a confined environment with a nice NixOS
 module to configure target users and provide launchers and desktop files for your privileged user.
@@ -31,7 +32,9 @@ nix run git+https://git.ophivana.moe/security/fortify -- -h
 
 ## Module usage
 
-The NixOS module currently requires home-manager and impermanence to function correctly.
+The NixOS module currently requires home-manager to function correctly.
+
+Full module documentation can be found [here](options.md).
 
 To use the module, import it into your configuration with
 
@@ -68,21 +71,21 @@ This adds the `environment.fortify` option:
 {
   environment.fortify = {
     enable = true;
-    user = "nixos";
+    stateDir = "/var/lib/persist/module/fortify";
-    stateDir = "/var/lib/persist/module";
+    users = {
-    target = {
+      alice = 0;
-      chronos = {
+      nixos = 10;
-        launchers = {
-          weechat.method = "sudo";
-          claws-mail.capability.pulse = false;
-
-          discord = {
-            command = "vesktop --ozone-platform-hint=wayland";
-            share = pkgs.vesktop;
     };
 
-          chromium.dbus = {
+    apps = [
-            configSystem = {
+      {
+        name = "chromium";
+        id = "org.chromium.Chromium";
+        packages = [ pkgs.chromium ];
+        userns = true;
+        mapRealUid = true;
+        dbus = {
+          system = {
             filter = true;
             talk = [
               "org.bluez"
@@ -90,8 +93,9 @@ This adds the `environment.fortify` option:
               "org.freedesktop.UPower"
             ];
           };
-            config = {
+          session =
-              filter = true;
+            f:
+            f {
               talk = [
                 "org.freedesktop.DBus"
                 "org.freedesktop.FileManager1"
@@ -106,74 +110,63 @@ This adds the `environment.fortify` option:
                 "org.mpris.MediaPlayer2.org.chromium.Chromium.*"
                 "org.mpris.MediaPlayer2.chromium.*"
               ];
-              call = {
+              call = { };
-                "org.freedesktop.portal.*" = "*";
+              broadcast = { };
-              };
-              broadcast = {
-                "org.freedesktop.portal.*" = "@/org/freedesktop/portal/*";
             };
         };
+      }
+      {
+        name = "claws-mail";
+        id = "org.claws_mail.Claws-Mail";
+        packages = [ pkgs.claws-mail ];
+        gpu = false;
+        capability.pulse = false;
+      }
+      {
+        name = "weechat";
+        packages = [ pkgs.weechat ];
+        capability = {
+          wayland = false;
+          x11 = false;
+          dbus = true;
+          pulse = false;
         };
+      }
+      {
+        name = "discord";
+        id = "dev.vencord.Vesktop";
+        packages = [ pkgs.vesktop ];
+        share = pkgs.vesktop;
+        command = "vesktop --ozone-platform-hint=wayland";
+        userns = true;
+        mapRealUid = true;
+        capability.x11 = true;
+        dbus = {
+          session =
+            f:
+            f {
+              talk = [ "org.kde.StatusNotifierWatcher" ];
+              own = [ ];
+              call = { };
+              broadcast = { };
             };
-        packages = with pkgs; [
+          system.filter = true;
-          weechat
+        };
-          claws-mail
+      }
-          vesktop
+      {
-          chromium
+        name = "looking-glass-client";
-        ];
+        groups = [ "plugdev" ];
-        persistence.directories = [
+        extraPaths = [
-          ".config/weechat"
+          {
-          ".claws-mail"
+            src = "/dev/shm/looking-glass";
-          ".config/vesktop"
+            write = true;
+          }
         ];
         extraConfig = {
           programs.looking-glass-client.enable = true;
         };
-      };
+      }
-    };
+    ];
   };
 }
 ```
-
-* `enable` determines whether the module should be enabled or not. Useful when sharing configurations between graphical
-  and headless systems. Defaults to `false`.
-
-* `user` specifies the privileged user with access to fortified applications.
-
-* `stateDir` is the path to your persistent storage location. It is directly passed through to the impermanence module.
-
-* `target` is an attribute set of submodules, where the attribute name is the username of the unprivileged target user.
-
-  The available options are:
-
-    * `packages`, the list of packages to make available in the target user's environment.
-
-    * `persistence`, user persistence attribute set passed to impermanence.
-
-    * `extraConfig`, extra home-manager configuration for the target user.
-
-    * `launchers`, attribute set where the attribute name is the name of the launcher.
-
-      The available options are:
-
-        * `command`, the command to run as the target user. Defaults to launcher name.
-
-        * `dbus.config`, D-Bus proxy custom configuration.
-
-        * `dbus.configSystem`, D-Bus system bus custom configuration, null to disable.
-
-        * `dbus.id`, D-Bus application id, has no effect if `dbus.config` is set.
-
-        * `dbus.mpris`, whether to enable MPRIS defaults, has no effect if `dbus.config` is set.
-
-        * `capability.wayland`, whether to share the Wayland socket.
-
-        * `capability.x11`, whether to share the X11 socket and allow connection.
-
-        * `capability.dbus`, whether to proxy D-Bus.
-
-        * `capability.pulse`, whether to share the PulseAudio socket and cookie.
-
-        * `share`, package containing desktop/icon files. Defaults to launcher name.
-
-        * `method`, the launch method for the sandboxed program, can be `"fortify"`, `"fortify-sudo"`, `"sudo"`.

acl/export.go

@@ -1,3 +1,4 @@
+// Package acl implements simple ACL manipulation via libacl.
 package acl
 
 import "unsafe"

cmd/finit/ipc/payload.go

@@ -1,6 +1,6 @@
 package init0
 
-const EnvInit = "FORTIFY_INIT"
+const Env = "FORTIFY_INIT"
 
 type Payload struct {
 	// target full exec path

cmd/finit/main.go

@@ -1,9 +1,8 @@
-package init0
+package main
 
 import (
 	"encoding/gob"
 	"errors"
-	"flag"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -12,58 +11,80 @@ import (
 	"syscall"
 	"time"
 
+	init0 "git.ophivana.moe/security/fortify/cmd/finit/ipc"
+	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
 )
 
 const (
-	// time to wait for linger processes after death initial process
+	// time to wait for linger processes after death of initial process
 	residualProcessTimeout = 5 * time.Second
 )
 
 // everything beyond this point runs within pid namespace
 // proceed with caution!
 
-func doInit(fd uintptr) {
+func main() {
+	// sharing stdout with shim
+	// USE WITH CAUTION
 	fmsg.SetPrefix("init")
 
+	// setting this prevents ptrace
+	if err := internal.PR_SET_DUMPABLE__SUID_DUMP_DISABLE(); err != nil {
+		fmsg.Fatalf("cannot set SUID_DUMP_DISABLE: %s", err)
+		panic("unreachable")
+	}
+
+	if os.Getpid() != 1 {
+		fmsg.Fatal("this process must run as pid 1")
+		panic("unreachable")
+	}
+
 	// re-exec
-	if len(os.Args) > 0 && os.Args[0] != "fortify" && path.IsAbs(os.Args[0]) {
+	if len(os.Args) > 0 && (os.Args[0] != "finit" || len(os.Args) != 1) && path.IsAbs(os.Args[0]) {
-		if err := syscall.Exec(os.Args[0], []string{"fortify", "init"}, os.Environ()); err != nil {
+		if err := syscall.Exec(os.Args[0], []string{"finit"}, os.Environ()); err != nil {
 			fmsg.Println("cannot re-exec self:", err)
 			// continue anyway
 		}
 	}
 
-	var payload Payload
+	// setup pipe fd from environment
-	p := os.NewFile(fd, "config-stream")
+	var setup *os.File
-	if p == nil {
+	if s, ok := os.LookupEnv(init0.Env); !ok {
-		fmsg.Fatal("invalid config descriptor")
+		fmsg.Fatal("FORTIFY_INIT not set")
-	}
+		panic("unreachable")
-	if err := gob.NewDecoder(p).Decode(&payload); err != nil {
+	} else {
-		fmsg.Fatal("cannot decode init payload:", err)
+		if fd, err := strconv.Atoi(s); err != nil {
+			fmsg.Fatalf("cannot parse %q: %v", s, err)
+			panic("unreachable")
+		} else {
+			setup = os.NewFile(uintptr(fd), "setup")
+			if setup == nil {
+				fmsg.Fatal("invalid config descriptor")
+				panic("unreachable")
+			}
+		}
+	}
+
+	var payload init0.Payload
+	if err := gob.NewDecoder(setup).Decode(&payload); err != nil {
+		fmsg.Fatal("cannot decode init setup payload:", err)
+		panic("unreachable")
 	} else {
-		// sharing stdout with parent
-		// USE WITH CAUTION
 		fmsg.SetVerbose(payload.Verbose)
 
 		// child does not need to see this
-		if err = os.Unsetenv(EnvInit); err != nil {
+		if err = os.Unsetenv(init0.Env); err != nil {
-			fmsg.Println("cannot unset", EnvInit+":", err)
+			fmsg.Printf("cannot unset %s: %v", init0.Env, err)
 			// not fatal
 		} else {
 			fmsg.VPrintln("received configuration")
 		}
 	}
 
-	// close config fd
-	if err := p.Close(); err != nil {
-		fmsg.Println("cannot close config fd:", err)
-		// not fatal
-	}
-
 	// die with parent
-	if _, _, errno := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_SET_PDEATHSIG, uintptr(syscall.SIGKILL), 0); errno != 0 {
+	if err := internal.PR_SET_PDEATHSIG__SIGKILL(); err != nil {
-		fmsg.Fatal("prctl(PR_SET_PDEATHSIG, SIGKILL):", errno.Error())
+		fmsg.Fatalf("prctl(PR_SET_PDEATHSIG, SIGKILL): %v", err)
 	}
 
 	cmd := exec.Command(payload.Argv0)
@@ -82,6 +103,13 @@ func doInit(fd uintptr) {
 	if err := cmd.Start(); err != nil {
 		fmsg.Fatalf("cannot start %q: %v", payload.Argv0, err)
 	}
+	fmsg.Suspend()
+
+	// close setup pipe as setup is now complete
+	if err := setup.Close(); err != nil {
+		fmsg.Println("cannot close setup pipe:", err)
+		// not fatal
+	}
 
 	sig := make(chan os.Signal, 2)
 	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
@@ -122,6 +150,7 @@ func doInit(fd uintptr) {
 		close(done)
 	}()
 
+	// closed after residualProcessTimeout has elapsed after initial process death
 	timeout := make(chan struct{})
 
 	r := 2
@@ -129,9 +158,13 @@ func doInit(fd uintptr) {
 		select {
 		case s := <-sig:
 			fmsg.VPrintln("received", s.String())
+			fmsg.Resume() // output could still be withheld at this point, so resume is called
 			fmsg.Exit(0)
 		case w := <-info:
 			if w.wpid == cmd.Process.Pid {
+				// initial process exited, output is most likely available again
+				fmsg.Resume()
+
 				switch {
 				case w.wstatus.Exited():
 					r = w.wstatus.ExitStatus()
@@ -154,21 +187,3 @@ func doInit(fd uintptr) {
 		}
 	}
 }
-
-// Try runs init and stops execution if FORTIFY_INIT is set.
-func Try() {
-	if os.Getpid() != 1 {
-		return
-	}
-
-	if args := flag.Args(); len(args) == 1 && args[0] == "init" {
-		if s, ok := os.LookupEnv(EnvInit); ok {
-			if fd, err := strconv.Atoi(s); err != nil {
-				fmsg.Fatalf("cannot parse %q: %v", s, err)
-			} else {
-				doInit(uintptr(fd))
-			}
-			panic("unreachable")
-		}
-	}
-}

cmd/fshim/ipc/payload.go

@@ -1,4 +1,4 @@
-package shim
+package shim0
 
 import (
 	"encoding/gob"
@@ -9,13 +9,13 @@ import (
 	"git.ophivana.moe/security/fortify/internal/fmsg"
 )
 
-const EnvShim = "FORTIFY_SHIM"
+const Env = "FORTIFY_SHIM"
 
 type Payload struct {
 	// child full argv
 	Argv []string
-	// fortify, bwrap, target full exec path
+	// bwrap, target full exec path
-	Exec [3]string
+	Exec [2]string
 	// bwrap config
 	Bwrap *bwrap.Config
 	// whether to pass wayland fd
@@ -25,7 +25,7 @@ type Payload struct {
 	Verbose bool
 }
 
-func (p *Payload) serve(conn *net.UnixConn, wl *Wayland) error {
+func (p *Payload) Serve(conn *net.UnixConn, wl *Wayland) error {
 	if err := gob.NewEncoder(conn).Encode(*p); err != nil {
 		return fmsg.WrapErrorSuffix(err,
 			"cannot stream shim payload:")

cmd/fshim/ipc/shim/shim.go

@@ -5,15 +5,21 @@ import (
 	"net"
 	"os"
 	"os/exec"
+	"os/signal"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"syscall"
 	"time"
 
 	"git.ophivana.moe/security/fortify/acl"
+	shim0 "git.ophivana.moe/security/fortify/cmd/fshim/ipc"
+	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
 )
 
+const shimSetupTimeout = 5 * time.Second
+
 // used by the parent process
 
 type Shim struct {
@@ -21,24 +27,26 @@ type Shim struct {
 	cmd *exec.Cmd
 	// uid of shim target user
 	uid uint32
-	// whether to check shim pid
+	// string representation of application id
-	checkPid bool
+	aid string
-	// user switcher executable path
+	// string representation of supplementary group ids
-	executable string
+	supp []string
 	// path to setup socket
 	socket string
 	// shim setup abort reason and completion
 	abort     chan error
 	abortErr  atomic.Pointer[error]
 	abortOnce sync.Once
+	// fallback exit notifier with error returned killing the process
+	killFallback chan error
 	// wayland mediation, nil if disabled
-	wl *Wayland
+	wl *shim0.Wayland
 	// shim setup payload
-	payload *Payload
+	payload *shim0.Payload
 }
 
-func New(executable string, uid uint32, socket string, wl *Wayland, payload *Payload, checkPid bool) *Shim {
+func New(uid uint32, aid string, supp []string, socket string, wl *shim0.Wayland, payload *shim0.Payload) *Shim {
-	return &Shim{uid: uid, executable: executable, socket: socket, wl: wl, payload: payload, checkPid: checkPid}
+	return &Shim{uid: uid, aid: aid, supp: supp, socket: socket, wl: wl, payload: payload}
 }
 
 func (s *Shim) String() string {
@@ -65,9 +73,11 @@ func (s *Shim) AbortWait(err error) {
 	<-s.abort
 }
 
-type CommandBuilder func(shimEnv string) (args []string)
+func (s *Shim) WaitFallback() chan error {
+	return s.killFallback
+}
 
-func (s *Shim) Start(f CommandBuilder) (*time.Time, error) {
+func (s *Shim) Start() (*time.Time, error) {
 	var (
 		cf     chan *net.UnixConn
 		accept func()
@@ -84,30 +94,65 @@ func (s *Shim) Start(f CommandBuilder) (*time.Time, error) {
 	}
 
 	// start user switcher process and save time
-	s.cmd = exec.Command(s.executable, f(EnvShim+"="+s.socket)...)
+	var fsu string
-	s.cmd.Env = []string{}
+	if p, ok := internal.Check(internal.Fsu); !ok {
+		fmsg.Fatal("invalid fsu path, this copy of fshim is not compiled correctly")
+		panic("unreachable")
+	} else {
+		fsu = p
+	}
+	s.cmd = exec.Command(fsu)
+	s.cmd.Env = []string{
+		shim0.Env + "=" + s.socket,
+		"FORTIFY_APP_ID=" + s.aid,
+	}
+	if len(s.supp) > 0 {
+		fmsg.VPrintf("attaching supplementary group ids %s", s.supp)
+		s.cmd.Env = append(s.cmd.Env, "FORTIFY_GROUPS="+strings.Join(s.supp, " "))
+	}
 	s.cmd.Stdin, s.cmd.Stdout, s.cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
 	s.cmd.Dir = "/"
-	fmsg.VPrintln("starting shim via user switcher:", s.cmd)
+	fmsg.VPrintln("starting shim via fsu:", s.cmd)
-	fmsg.Withhold() // withhold messages to stderr
+	fmsg.Suspend() // withhold messages to stderr
 	if err := s.cmd.Start(); err != nil {
 		return nil, fmsg.WrapErrorSuffix(err,
-			"cannot start user switcher:")
+			"cannot start fsu:")
 	}
 	startTime := time.Now().UTC()
 
 	// kill shim if something goes wrong and an error is returned
+	s.killFallback = make(chan error, 1)
 	killShim := func() {
 		if err := s.cmd.Process.Signal(os.Interrupt); err != nil {
-			fmsg.Println("cannot terminate shim on faulted setup:", err)
+			s.killFallback <- err
 		}
 	}
 	defer func() { killShim() }()
 
+	// take alternative exit path on signal
+	sig := make(chan os.Signal, 2)
+	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
+	go func() {
+		v := <-sig
+		fmsg.Printf("got %s after program start", v)
+		s.killFallback <- nil
+		signal.Ignore(syscall.SIGINT, syscall.SIGTERM)
+	}()
+
 	accept()
-	conn := <-cf
+	var conn *net.UnixConn
-	if conn == nil {
+	select {
+	case c := <-cf:
+		if c == nil {
 			return &startTime, fmsg.WrapErrorSuffix(*s.abortErr.Load(), "cannot accept call on setup socket:")
+		} else {
+			conn = c
+		}
+	case <-time.After(shimSetupTimeout):
+		err := fmsg.WrapError(errors.New("timed out waiting for shim"),
+			"timed out waiting for shim to connect")
+		s.AbortWait(err)
+		return &startTime, err
 	}
 
 	// authenticate against called provided uid and shim pid
@@ -119,7 +164,7 @@ func (s *Shim) Start(f CommandBuilder) (*time.Time, error) {
 		err = errors.New("compromised fortify build")
 		s.Abort(err)
 		return &startTime, err
-	} else if s.checkPid && cred.Pid != int32(s.cmd.Process.Pid) {
+	} else if cred.Pid != int32(s.cmd.Process.Pid) {
 		fmsg.Printf("process %d tried to connect to shim setup socket, expecting shim %d",
 			cred.Pid, s.cmd.Process.Pid)
 		err = errors.New("compromised target user")
@@ -129,7 +174,7 @@ func (s *Shim) Start(f CommandBuilder) (*time.Time, error) {
 
 	// serve payload and wayland fd if enabled
 	// this also closes the connection
-	err := s.payload.serve(conn, s.wl)
+	err := s.payload.Serve(conn, s.wl)
 	if err == nil {
 		killShim = func() {}
 	}
@@ -158,6 +203,7 @@ func (s *Shim) serve() (chan *net.UnixConn, func(), error) {
 		}
 
 		go func() {
+			cfWg := new(sync.WaitGroup)
 			for {
 				select {
 				case err = <-s.abort:
@@ -168,15 +214,24 @@ func (s *Shim) serve() (chan *net.UnixConn, func(), error) {
 						fmsg.Println("cannot close setup socket:", err)
 					}
 					close(s.abort)
+					go func() {
+						cfWg.Wait()
 						close(cf)
+					}()
 					return
 				case <-accept:
+					cfWg.Add(1)
+					go func() {
+						defer cfWg.Done()
 						if conn, err0 := l.AcceptUnix(); err0 != nil {
-						s.Abort(err0) // does not block, breaks loop
+							// breaks loop
-						cf <- nil     // receiver sees nil value and loads err0 stored during abort
+							s.Abort(err0)
+							// receiver sees nil value and loads err0 stored during abort
+							cf <- nil
 						} else {
 							cf <- conn
 						}
+					}()
 				}
 			}
 		}()

cmd/fshim/ipc/wayland.go

@@ -1,4 +1,4 @@
-package shim
+package shim0
 
 import (
 	"fmt"

cmd/fshim/main.go

@@ -1,50 +1,74 @@
-package shim
+package main
 
 import (
 	"encoding/gob"
 	"errors"
-	"flag"
 	"net"
 	"os"
 	"path"
 	"strconv"
 	"syscall"
 
+	init0 "git.ophivana.moe/security/fortify/cmd/finit/ipc"
+	shim "git.ophivana.moe/security/fortify/cmd/fshim/ipc"
 	"git.ophivana.moe/security/fortify/helper"
+	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
-	init0 "git.ophivana.moe/security/fortify/internal/init"
 )
 
-// everything beyond this point runs as target user
+// everything beyond this point runs as unconstrained target user
 // proceed with caution!
 
-func doShim(socket string) {
+func main() {
+	// sharing stdout with fortify
+	// USE WITH CAUTION
 	fmsg.SetPrefix("shim")
 
+	// setting this prevents ptrace
+	if err := internal.PR_SET_DUMPABLE__SUID_DUMP_DISABLE(); err != nil {
+		fmsg.Fatalf("cannot set SUID_DUMP_DISABLE: %s", err)
+		panic("unreachable")
+	}
+
 	// re-exec
-	if len(os.Args) > 0 && os.Args[0] != "fortify" && path.IsAbs(os.Args[0]) {
+	if len(os.Args) > 0 && (os.Args[0] != "fshim" || len(os.Args) != 1) && path.IsAbs(os.Args[0]) {
-		if err := syscall.Exec(os.Args[0], []string{"fortify", "shim"}, os.Environ()); err != nil {
+		if err := syscall.Exec(os.Args[0], []string{"fshim"}, os.Environ()); err != nil {
 			fmsg.Println("cannot re-exec self:", err)
 			// continue anyway
 		}
 	}
 
+	// lookup socket path from environment
+	var socketPath string
+	if s, ok := os.LookupEnv(shim.Env); !ok {
+		fmsg.Fatal("FORTIFY_SHIM not set")
+		panic("unreachable")
+	} else {
+		socketPath = s
+	}
+
+	// check path to finit
+	var finitPath string
+	if p, ok := internal.Path(internal.Finit); !ok {
+		fmsg.Fatal("invalid finit path, this copy of fshim is not compiled correctly")
+	} else {
+		finitPath = p
+	}
+
 	// dial setup socket
 	var conn *net.UnixConn
-	if c, err := net.DialUnix("unix", nil, &net.UnixAddr{Name: socket, Net: "unix"}); err != nil {
+	if c, err := net.DialUnix("unix", nil, &net.UnixAddr{Name: socketPath, Net: "unix"}); err != nil {
-		fmsg.Fatal("cannot dial setup socket:", err)
+		fmsg.Fatal(err.Error())
 		panic("unreachable")
 	} else {
 		conn = c
 	}
 
 	// decode payload gob stream
-	var payload Payload
+	var payload shim.Payload
 	if err := gob.NewDecoder(conn).Decode(&payload); err != nil {
-		fmsg.Fatal("cannot decode shim payload:", err)
+		fmsg.Fatalf("cannot decode shim payload: %v", err)
 	} else {
-		// sharing stdout with parent
-		// USE WITH CAUTION
 		fmsg.SetVerbose(payload.Verbose)
 	}
 
@@ -56,7 +80,7 @@ func doShim(socket string) {
 	wfd := -1
 	if payload.WL {
 		if fd, err := receiveWLfd(conn); err != nil {
-			fmsg.Fatal("cannot receive wayland fd:", err)
+			fmsg.Fatalf("cannot receive wayland fd: %v", err)
 		} else {
 			wfd = fd
 		}
@@ -74,11 +98,14 @@ func doShim(socket string) {
 	ic.Argv = payload.Argv
 	if len(ic.Argv) > 0 {
 		// looked up from $PATH by parent
-		ic.Argv0 = payload.Exec[2]
+		ic.Argv0 = payload.Exec[1]
 	} else {
 		// no argv, look up shell instead
 		var ok bool
-		if ic.Argv0, ok = os.LookupEnv("SHELL"); !ok {
+		if payload.Bwrap.SetEnv == nil {
+			fmsg.Fatal("no command was specified and environment is unset")
+		}
+		if ic.Argv0, ok = payload.Bwrap.SetEnv["SHELL"]; !ok {
 			fmsg.Fatal("no command was specified and $SHELL was unset")
 		}
 
@@ -101,23 +128,24 @@ func doShim(socket string) {
 
 	// share config pipe
 	if r, w, err := os.Pipe(); err != nil {
-		fmsg.Fatal("cannot pipe:", err)
+		fmsg.Fatalf("cannot pipe: %v", err)
 	} else {
-		conf.SetEnv[init0.EnvInit] = strconv.Itoa(3 + len(extraFiles))
+		conf.SetEnv[init0.Env] = strconv.Itoa(3 + len(extraFiles))
 		extraFiles = append(extraFiles, r)
 
 		fmsg.VPrintln("transmitting config to init")
 		go func() {
 			// stream config to pipe
 			if err = gob.NewEncoder(w).Encode(&ic); err != nil {
-				fmsg.Fatal("cannot transmit init config:", err)
+				fmsg.Fatalf("cannot transmit init config: %v", err)
 			}
 		}()
 	}
 
-	helper.BubblewrapName = payload.Exec[1] // resolved bwrap path by parent
+	helper.BubblewrapName = payload.Exec[0] // resolved bwrap path by parent
-	if b, err := helper.NewBwrap(conf, nil, payload.Exec[0], func(int, int) []string { return []string{"init"} }); err != nil {
+	if b, err := helper.NewBwrap(conf, nil, finitPath,
-		fmsg.Fatal("malformed sandbox config:", err)
+		func(int, int) []string { return make([]string, 0) }); err != nil {
+		fmsg.Fatalf("malformed sandbox config: %v", err)
 	} else {
 		cmd := b.Unwrap()
 		cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
@@ -129,7 +157,7 @@ func doShim(socket string) {
 
 		// run and pass through exit code
 		if err = b.Start(); err != nil {
-			fmsg.Fatal("cannot start target process:", err)
+			fmsg.Fatalf("cannot start target process: %v", err)
 		} else if err = b.Wait(); err != nil {
 			fmsg.VPrintln("wait:", err)
 		}
@@ -167,13 +195,3 @@ func receiveWLfd(conn *net.UnixConn) (int, error) {
 		return fds[0], nil
 	}
 }
-
-// Try runs shim and stops execution if FORTIFY_SHIM is set.
-func Try() {
-	if args := flag.Args(); len(args) == 1 && args[0] == "shim" {
-		if s, ok := os.LookupEnv(EnvShim); ok {
-			doShim(s)
-			panic("unreachable")
-		}
-	}
-}

cmd/fsu/main.go

@@ -1,25 +1,31 @@
 package main
 
 import (
-	"bufio"
+	"bytes"
+	"fmt"
 	"log"
 	"os"
 	"path"
+	"slices"
 	"strconv"
 	"strings"
 	"syscall"
 )
 
 const (
+	compPoison  = "INVALIDINVALIDINVALIDINVALIDINVALID"
 	fsuConfFile = "/etc/fsurc"
 	envShim     = "FORTIFY_SHIM"
 	envAID      = "FORTIFY_APP_ID"
+	envGroups   = "FORTIFY_GROUPS"
 
-	fpPoison = "INVALIDINVALIDINVALIDINVALIDINVALID"
+	PR_SET_NO_NEW_PRIVS = 0x26
 )
 
-// FortifyPath is the path to fortify, set at compile time.
+var (
-var FortifyPath = fpPoison
+	Fmain = compPoison
+	Fshim = compPoison
+)
 
 func main() {
 	log.SetFlags(0)
@@ -35,9 +41,16 @@ func main() {
 		log.Fatal("this program must not be started by root")
 	}
 
-	// validate compiled in fortify path
+	var fmain, fshim string
-	if FortifyPath == fpPoison || !path.IsAbs(FortifyPath) {
+	if p, ok := checkPath(Fmain); !ok {
 		log.Fatal("invalid fortify path, this copy of fsu is not compiled correctly")
+	} else {
+		fmain = p
+	}
+	if p, ok := checkPath(Fshim); !ok {
+		log.Fatal("invalid fshim path, this copy of fsu is not compiled correctly")
+	} else {
+		fshim = p
 	}
 
 	pexe := path.Join("/proc", strconv.Itoa(os.Getppid()), "exe")
@@ -45,7 +58,7 @@ func main() {
 		log.Fatalf("cannot read parent executable path: %v", err)
 	} else if strings.HasSuffix(p, " (deleted)") {
 		log.Fatal("fortify executable has been deleted")
-	} else if p != FortifyPath {
+	} else if p != fmain {
 		log.Fatal("this program must be started by fortify")
 	}
 
@@ -61,80 +74,76 @@ func main() {
 		uid += fid * 10000
 	}
 
+	// allowed aid range 0 to 9999
+	if as, ok := os.LookupEnv(envAID); !ok {
+		log.Fatal("FORTIFY_APP_ID not set")
+	} else if aid, err := parseUint32Fast(as); err != nil || aid < 0 || aid > 9999 {
+		log.Fatal("invalid aid")
+	} else {
+		uid += aid
+	}
+
 	// pass through setup path to shim
 	var shimSetupPath string
 	if s, ok := os.LookupEnv(envShim); !ok {
-		log.Fatal("FORTIFY_SHIM not set")
+		// fortify requests target uid
+		// print resolved uid and exit
+		fmt.Print(uid)
+		os.Exit(0)
 	} else if !path.IsAbs(s) {
 		log.Fatal("FORTIFY_SHIM is not absolute")
 	} else {
 		shimSetupPath = s
 	}
 
-	// allowed aid range 0 to 9999
+	// supplementary groups
-	if as, ok := os.LookupEnv(envAID); !ok {
+	var suppGroups, suppCurrent []int
-		log.Fatal("FORTIFY_APP_ID not set")
+
-	} else if aid, err := strconv.Atoi(as); err != nil || aid < 0 || aid > 9999 {
+	if gs, ok := os.LookupEnv(envGroups); ok {
-		log.Fatal("invalid aid")
+		if cur, err := os.Getgroups(); err != nil {
+			log.Fatalf("cannot get groups: %v", err)
 		} else {
-		uid += aid
+			suppCurrent = cur
 		}
 
+		// parse space-separated list of group ids
+		gss := bytes.Split([]byte(gs), []byte{' '})
+		suppGroups = make([]int, len(gss)+1)
+		for i, s := range gss {
+			if gid, err := strconv.Atoi(string(s)); err != nil {
+				log.Fatalf("cannot parse %q: %v", string(s), err)
+			} else if gid > 0 && gid != uid && gid != os.Getgid() && slices.Contains(suppCurrent, gid) {
+				suppGroups[i] = gid
+			} else {
+				log.Fatalf("invalid gid %d", gid)
+			}
+		}
+		suppGroups[len(suppGroups)-1] = uid
+	} else {
+		suppGroups = []int{uid}
+	}
+
+	// careful! users in the allowlist is effectively allowed to drop groups via fsu
+
 	if err := syscall.Setresgid(uid, uid, uid); err != nil {
 		log.Fatalf("cannot set gid: %v", err)
 	}
+	if err := syscall.Setgroups(suppGroups); err != nil {
+		log.Fatalf("cannot set supplementary groups: %v", err)
+	}
 	if err := syscall.Setresuid(uid, uid, uid); err != nil {
 		log.Fatalf("cannot set uid: %v", err)
 	}
-	if err := syscall.Exec(FortifyPath, []string{"fortify", "shim"}, []string{envShim + "=" + shimSetupPath}); err != nil {
+	if _, _, errno := syscall.AllThreadsSyscall(syscall.SYS_PRCTL, PR_SET_NO_NEW_PRIVS, 1, 0); errno != 0 {
+		log.Fatalf("cannot set no_new_privs flag: %s", errno.Error())
+	}
+	if err := syscall.Exec(fshim, []string{"fshim"}, []string{envShim + "=" + shimSetupPath}); err != nil {
 		log.Fatalf("cannot start shim: %v", err)
 	}
 
 	panic("unreachable")
 }
 
-func parseConfig(p string, puid int) (fid int, ok bool) {
+func checkPath(p string) (string, bool) {
-	// refuse to run if fsurc is not protected correctly
+	return p, p != compPoison && p != "" && path.IsAbs(p)
-	if s, err := os.Stat(p); err != nil {
-		log.Fatal(err)
-	} else if s.Mode().Perm() != 0400 {
-		log.Fatal("bad fsurc perm")
-	} else if st := s.Sys().(*syscall.Stat_t); st.Uid != 0 || st.Gid != 0 {
-		log.Fatal("fsurc must be owned by uid 0")
-	}
-
-	if r, err := os.Open(p); err != nil {
-		log.Fatal(err)
-		return -1, false
-	} else {
-		s := bufio.NewScanner(r)
-		var line int
-		for s.Scan() {
-			line++
-
-			// <puid> <fid>
-			lf := strings.SplitN(s.Text(), " ", 2)
-			if len(lf) != 2 {
-				log.Fatalf("invalid entry on line %d", line)
-			}
-
-			var puid0 int
-			if puid0, err = strconv.Atoi(lf[0]); err != nil || puid0 < 1 {
-				log.Fatalf("invalid parent uid on line %d", line)
-			}
-
-			ok = puid0 == puid
-			if ok {
-				// allowed fid range 0 to 99
-				if fid, err = strconv.Atoi(lf[1]); err != nil || fid < 0 || fid > 99 {
-					log.Fatalf("invalid fortify uid on line %d", line)
-				}
-				return
-			}
-		}
-		if err = s.Err(); err != nil {
-			log.Fatalf("cannot read fsurc: %v", err)
-		}
-		return -1, false
-	}
 }

cmd/fsu/parse.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+	"syscall"
+)
+
+func parseUint32Fast(s string) (int, error) {
+	sLen := len(s)
+	if sLen < 1 {
+		return -1, errors.New("zero length string")
+	}
+	if sLen > 10 {
+		return -1, errors.New("string too long")
+	}
+
+	n := 0
+	for i, ch := range []byte(s) {
+		ch -= '0'
+		if ch > 9 {
+			return -1, fmt.Errorf("invalid character '%s' at index %d", string([]byte{ch}), i)
+		}
+		n = n*10 + int(ch)
+	}
+	return n, nil
+}
+
+func parseConfig(p string, puid int) (fid int, ok bool) {
+	// refuse to run if fsurc is not protected correctly
+	if s, err := os.Stat(p); err != nil {
+		log.Fatal(err)
+	} else if s.Mode().Perm() != 0400 {
+		log.Fatal("bad fsurc perm")
+	} else if st := s.Sys().(*syscall.Stat_t); st.Uid != 0 || st.Gid != 0 {
+		log.Fatal("fsurc must be owned by uid 0")
+	}
+
+	if r, err := os.Open(p); err != nil {
+		log.Fatal(err)
+		return -1, false
+	} else {
+		s := bufio.NewScanner(r)
+		var line int
+		for s.Scan() {
+			line++
+
+			// <puid> <fid>
+			lf := strings.SplitN(s.Text(), " ", 2)
+			if len(lf) != 2 {
+				log.Fatalf("invalid entry on line %d", line)
+			}
+
+			var puid0 int
+			if puid0, err = parseUint32Fast(lf[0]); err != nil || puid0 < 1 {
+				log.Fatalf("invalid parent uid on line %d", line)
+			}
+
+			ok = puid0 == puid
+			if ok {
+				// allowed fid range 0 to 99
+				if fid, err = parseUint32Fast(lf[1]); err != nil || fid < 0 || fid > 99 {
+					log.Fatalf("invalid fortify uid on line %d", line)
+				}
+				return
+			}
+		}
+		if err = s.Err(); err != nil {
+			log.Fatalf("cannot read fsurc: %v", err)
+		}
+		return -1, false
+	}
+}

cmd/fuserdb/main.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"bytes"
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"path"
+	"strconv"
+
+	"git.ophivana.moe/security/fortify/internal/fmsg"
+)
+
+func main() {
+	fmsg.SetPrefix("fuserdb")
+
+	const varEmpty = "/var/empty"
+
+	out := flag.String("o", "userdb", "output directory")
+	homeDir := flag.String("d", varEmpty, "parent of home directories")
+	shell := flag.String("s", "/sbin/nologin", "absolute path to subordinate user shell")
+	flag.Parse()
+
+	type user struct {
+		name string
+		fid  int
+	}
+
+	users := make([]user, len(flag.Args()))
+	for i, s := range flag.Args() {
+		f := bytes.SplitN([]byte(s), []byte{':'}, 2)
+		if len(f) != 2 {
+			fmsg.Fatalf("invalid entry at index %d", i)
+		}
+		users[i].name = string(f[0])
+		if fid, err := strconv.Atoi(string(f[1])); err != nil {
+			fmsg.Fatal(err.Error())
+		} else {
+			users[i].fid = fid
+		}
+	}
+
+	if err := os.MkdirAll(*out, 0755); err != nil && !errors.Is(err, os.ErrExist) {
+		fmsg.Fatalf("cannot create output: %v", err)
+	}
+
+	for _, u := range users {
+		fidString := strconv.Itoa(u.fid)
+		for aid := 0; aid < 10000; aid++ {
+			userName := fmt.Sprintf("u%d_a%d", u.fid, aid)
+			uid := 1000000 + u.fid*10000 + aid
+			us := strconv.Itoa(uid)
+			realName := fmt.Sprintf("Fortify subordinate user %d (%s)", aid, u.name)
+			var homeDirectory string
+			if *homeDir != varEmpty {
+				homeDirectory = path.Join(*homeDir, fidString, strconv.Itoa(aid))
+			} else {
+				homeDirectory = varEmpty
+			}
+
+			writeUser(userName, uid, us, realName, homeDirectory, *shell, *out)
+			writeGroup(userName, uid, us, nil, *out)
+		}
+	}
+
+	fmsg.Printf("created %d entries", len(users)*2*10000)
+	fmsg.Exit(0)
+}

cmd/fuserdb/payload.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path"
+
+	"git.ophivana.moe/security/fortify/internal/fmsg"
+)
+
+type payloadU struct {
+	UserName      string   `json:"userName"`
+	Uid           int      `json:"uid"`
+	Gid           int      `json:"gid"`
+	MemberOf      []string `json:"memberOf,omitempty"`
+	RealName      string   `json:"realName"`
+	HomeDirectory string   `json:"homeDirectory"`
+	Shell         string   `json:"shell"`
+}
+
+func writeUser(userName string, uid int, us string, realName, homeDirectory, shell string, out string) {
+	userFileName := userName + ".user"
+	if f, err := os.OpenFile(path.Join(out, userFileName), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644); err != nil {
+		fmsg.Fatalf("cannot create %s: %v", userName, err)
+	} else if err = json.NewEncoder(f).Encode(&payloadU{
+		UserName:      userName,
+		Uid:           uid,
+		Gid:           uid,
+		RealName:      realName,
+		HomeDirectory: homeDirectory,
+		Shell:         shell,
+	}); err != nil {
+		fmsg.Fatalf("cannot serialise %s: %v", userName, err)
+	} else if err = f.Close(); err != nil {
+		fmsg.Printf("cannot close %s: %v", userName, err)
+	}
+	if err := os.Symlink(userFileName, path.Join(out, us+".user")); err != nil {
+		fmsg.Fatalf("cannot link %s: %v", userName, err)
+	}
+}
+
+type payloadG struct {
+	GroupName string   `json:"groupName"`
+	Gid       int      `json:"gid"`
+	Members   []string `json:"members,omitempty"`
+}
+
+func writeGroup(groupName string, gid int, gs string, members []string, out string) {
+	groupFileName := groupName + ".group"
+	if f, err := os.OpenFile(path.Join(out, groupFileName), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644); err != nil {
+		fmsg.Fatalf("cannot create %s: %v", groupName, err)
+	} else if err = json.NewEncoder(f).Encode(&payloadG{
+		GroupName: groupName,
+		Gid:       gid,
+		Members:   members,
+	}); err != nil {
+		fmsg.Fatalf("cannot serialise %s: %v", groupName, err)
+	} else if err = f.Close(); err != nil {
+		fmsg.Printf("cannot close %s: %v", groupName, err)
+	}
+	if err := os.Symlink(groupFileName, path.Join(out, gs+".group")); err != nil {
+		fmsg.Fatalf("cannot link %s: %v", groupName, err)
+	}
+}

config.go

@@ -1,135 +0,0 @@
-package main
-
-import (
-	"encoding/json"
-	"flag"
-	"fmt"
-
-	"git.ophivana.moe/security/fortify/dbus"
-	"git.ophivana.moe/security/fortify/internal/app"
-	"git.ophivana.moe/security/fortify/internal/fmsg"
-	"git.ophivana.moe/security/fortify/internal/system"
-)
-
-var (
-	printTemplate bool
-
-	confPath string
-
-	dbusConfigSession string
-	dbusConfigSystem  string
-	dbusID            string
-	mpris             bool
-	dbusVerbose       bool
-
-	userName    string
-	enablements [system.ELen]bool
-
-	launchMethodText string
-)
-
-func init() {
-	flag.BoolVar(&printTemplate, "template", false, "Print a full config template and exit")
-
-	// config file, disables every other flag here
-	flag.StringVar(&confPath, "c", "nil", "Path to full app configuration, or \"nil\" to configure from flags")
-
-	flag.StringVar(&dbusConfigSession, "dbus-config", "builtin", "Path to D-Bus proxy config file, or \"builtin\" for defaults")
-	flag.StringVar(&dbusConfigSystem, "dbus-system", "nil", "Path to system D-Bus proxy config file, or \"nil\" to disable")
-	flag.StringVar(&dbusID, "dbus-id", "", "D-Bus ID of application, leave empty to disable own paths, has no effect if custom config is available")
-	flag.BoolVar(&mpris, "mpris", false, "Allow owning MPRIS D-Bus path, has no effect if custom config is available")
-	flag.BoolVar(&dbusVerbose, "dbus-log", false, "Force logging in the D-Bus proxy")
-
-	flag.StringVar(&userName, "u", "chronos", "Passwd name of user to run as")
-	flag.BoolVar(&enablements[system.EWayland], "wayland", false, "Share Wayland socket")
-	flag.BoolVar(&enablements[system.EX11], "X", false, "Share X11 socket and allow connection")
-	flag.BoolVar(&enablements[system.EDBus], "dbus", false, "Proxy D-Bus connection")
-	flag.BoolVar(&enablements[system.EPulse], "pulse", false, "Share PulseAudio socket and cookie")
-}
-
-func init() {
-	methodHelpString := "Method of launching the child process, can be one of \"sudo\""
-	if os.SdBooted() {
-		methodHelpString += ", \"systemd\""
-	}
-
-	flag.StringVar(&launchMethodText, "method", "sudo", methodHelpString)
-}
-
-func tryTemplate() {
-	if printTemplate {
-		if s, err := json.MarshalIndent(app.Template(), "", "  "); err != nil {
-			fmsg.Fatalf("cannot generate template: %v", err)
-			panic("unreachable")
-		} else {
-			fmt.Println(string(s))
-		}
-		fmsg.Exit(0)
-	}
-}
-
-func loadConfig() *app.Config {
-	if confPath == "nil" {
-		// config from flags
-		return configFromFlags()
-	} else {
-		// config from file
-		c := new(app.Config)
-		if f, err := os.Open(confPath); err != nil {
-			fmsg.Fatalf("cannot access config file %q: %s", confPath, err)
-			panic("unreachable")
-		} else if err = json.NewDecoder(f).Decode(&c); err != nil {
-			fmsg.Fatalf("cannot parse config file %q: %s", confPath, err)
-			panic("unreachable")
-		} else {
-			return c
-		}
-	}
-}
-
-func configFromFlags() (config *app.Config) {
-	// initialise config from flags
-	config = &app.Config{
-		ID:      dbusID,
-		User:    userName,
-		Command: flag.Args(),
-		Method:  launchMethodText,
-	}
-
-	// enablements from flags
-	for i := system.Enablement(0); i < system.Enablement(system.ELen); i++ {
-		if enablements[i] {
-			config.Confinement.Enablements.Set(i)
-		}
-	}
-
-	// parse D-Bus config file from flags if applicable
-	if enablements[system.EDBus] {
-		if dbusConfigSession == "builtin" {
-			config.Confinement.SessionBus = dbus.NewConfig(dbusID, true, mpris)
-		} else {
-			if c, err := dbus.NewConfigFromFile(dbusConfigSession); err != nil {
-				fmsg.Fatalf("cannot load session bus proxy config from %q: %s", dbusConfigSession, err)
-			} else {
-				config.Confinement.SessionBus = c
-			}
-		}
-
-		// system bus proxy is optional
-		if dbusConfigSystem != "nil" {
-			if c, err := dbus.NewConfigFromFile(dbusConfigSystem); err != nil {
-				fmsg.Fatalf("cannot load system bus proxy config from %q: %s", dbusConfigSystem, err)
-			} else {
-				config.Confinement.SystemBus = c
-			}
-		}
-
-		// override log from configuration
-		if dbusVerbose {
-			config.Confinement.SessionBus.Log = true
-			config.Confinement.SystemBus.Log = true
-		}
-	}
-
-	return
-}

dbus/dbus.go

@@ -1,3 +1,4 @@
+// Package dbus wraps xdg-dbus-proxy and implements configuration and sandboxing of the underlying helper process.
 package dbus
 
 import (

flake.nix

@@ -42,6 +42,33 @@
             with nixpkgsFor.${system};
             self.packages.${system}.fortify.buildInputs ++ [ self.packages.${system}.fortify ];
         };
+
+        generateDoc =
+          let
+            pkgs = nixpkgsFor.${system};
+            inherit (pkgs) lib;
+
+            doc =
+              let
+                eval = lib.evalModules {
+                  specialArgs = {
+                    inherit pkgs;
+                  };
+                  modules = [ ./options.nix ];
+                };
+                cleanEval = lib.filterAttrsRecursive (n: v: n != "_module") eval;
+              in
+              pkgs.nixosOptionsDoc { inherit (cleanEval) options; };
+            docText = pkgs.runCommand "fortify-module-docs.md" { } ''
+              cat ${doc.optionsCommonMark} > $out
+              sed -i '/*Declared by:*/,+1 d' $out
+            '';
+          in
+          nixpkgsFor.${system}.mkShell {
+            shellHook = ''
+              exec cat ${docText} > options.md
+            '';
+          };
       });
     };
 }

helper/helper.go

@@ -1,6 +1,4 @@
-/*
+// Package helper runs external helpers with optional sandboxing and manages their status/args pipes.
-Package helper runs external helpers and manages their status and args FDs.
-*/
 package helper
 
 import (

internal/app/app.go

@@ -3,8 +3,8 @@ package app
 import (
 	"sync"
 
-	"git.ophivana.moe/security/fortify/internal"
+	"git.ophivana.moe/security/fortify/cmd/fshim/ipc/shim"
-	"git.ophivana.moe/security/fortify/internal/shim"
+	"git.ophivana.moe/security/fortify/internal/linux"
 )
 
 type App interface {
@@ -25,7 +25,7 @@ type app struct {
 	// application unique identifier
 	id *ID
 	// operating system interface
-	os internal.System
+	os linux.System
 	// shim process manager
 	shim *shim.Shim
 	// child process related information
@@ -53,7 +53,7 @@ func (a *app) String() string {
 	}
 
 	if a.seal != nil {
-		return "(sealed fortified app as uid " + a.seal.sys.user.Uid + ")"
+		return "(sealed fortified app as uid " + a.seal.sys.user.us + ")"
 	}
 
 	return "(unsealed fortified app)"
@@ -63,7 +63,7 @@ func (a *app) WaitErr() error {
 	return a.waitErr
 }
 
-func New(os internal.System) (App, error) {
+func New(os linux.System) (App, error) {
 	a := new(app)
 	a.id = new(ID)
 	a.os = os

internal/app/app_nixos_test.go

@@ -2,6 +2,7 @@ package app_test
 
 import (
 	"fmt"
+	"io"
 	"io/fs"
 	"os/user"
 	"strconv"
@@ -9,8 +10,8 @@ import (
 	"git.ophivana.moe/security/fortify/acl"
 	"git.ophivana.moe/security/fortify/dbus"
 	"git.ophivana.moe/security/fortify/helper/bwrap"
-	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/app"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
@@ -18,9 +19,12 @@ var testCasesNixos = []sealTestCase{
 	{
 		"nixos permissive defaults no enablements", new(stubNixOS),
 		&app.Config{
-			User:    "chronos",
 			Command: make([]string, 0),
-			Method:  "sudo",
+			Confinement: app.ConfinementConfig{
+				AppID:    0,
+				Username: "chronos",
+				Outer:    "/home/chronos",
+			},
 		},
 		app.ID{
 			0x4a, 0x45, 0x0b, 0x65,
@@ -28,11 +32,11 @@ var testCasesNixos = []sealTestCase{
 			0xbd, 0x01, 0x78, 0x0e,
 			0xb9, 0xa6, 0x07, 0xac,
 		},
-		system.New(150).
+		system.New(1000000).
-			Ensure("/tmp/fortify.1971", 0701).
+			Ensure("/tmp/fortify.1971", 0711).
-			Ephemeral(system.Process, "/tmp/fortify.1971/4a450b6596d7bc15bd01780eb9a607ac", 0701).
+			Ephemeral(system.Process, "/tmp/fortify.1971/4a450b6596d7bc15bd01780eb9a607ac", 0711).
 			Ensure("/tmp/fortify.1971/tmpdir", 0700).UpdatePermType(system.User, "/tmp/fortify.1971/tmpdir", acl.Execute).
-			Ensure("/tmp/fortify.1971/tmpdir/150", 01700).UpdatePermType(system.User, "/tmp/fortify.1971/tmpdir/150", acl.Read, acl.Write, acl.Execute).
+			Ensure("/tmp/fortify.1971/tmpdir/0", 01700).UpdatePermType(system.User, "/tmp/fortify.1971/tmpdir/0", acl.Read, acl.Write, acl.Execute).
 			Ensure("/run/user/1971/fortify", 0700).UpdatePermType(system.User, "/run/user/1971/fortify", acl.Execute).
 			Ensure("/run/user/1971", 0700).UpdatePermType(system.User, "/run/user/1971", acl.Execute). // this is ordered as is because the previous Ensure only calls mkdir if XDG_RUNTIME_DIR is unset
 			Ephemeral(system.Process, "/run/user/1971/fortify/4a450b6596d7bc15bd01780eb9a607ac", 0700).UpdatePermType(system.Process, "/run/user/1971/fortify/4a450b6596d7bc15bd01780eb9a607ac", acl.Execute).
@@ -42,23 +46,24 @@ var testCasesNixos = []sealTestCase{
 			Net:      true,
 			UserNS:   true,
 			Clearenv: true,
+			Chdir:    "/home/chronos",
 			SetEnv: map[string]string{
 				"HOME":              "/home/chronos",
 				"SHELL":             "/run/current-system/sw/bin/zsh",
 				"TERM":              "xterm-256color",
 				"USER":              "chronos",
-				"XDG_RUNTIME_DIR":   "/run/user/150",
+				"XDG_RUNTIME_DIR":   "/run/user/65534",
 				"XDG_SESSION_CLASS": "user",
 				"XDG_SESSION_TYPE":  "tty"},
 			Chmod:         make(bwrap.ChmodConfig),
 			DieWithParent: true,
 			AsInit:        true,
 		}).SetUID(65534).SetGID(65534).
-			Procfs("/proc").DevTmpfs("/dev").Mqueue("/dev/mqueue").
+			Procfs("/proc").
-			Tmpfs("/dev/fortify", 4096).
+			Tmpfs("/fortify", 4096).
+			DevTmpfs("/dev").Mqueue("/dev/mqueue").
 			Bind("/bin", "/bin", false, true).
 			Bind("/boot", "/boot", false, true).
-			Bind("/etc", "/dev/fortify/etc").
 			Bind("/home", "/home", false, true).
 			Bind("/lib", "/lib", false, true).
 			Bind("/lib64", "/lib64", false, true).
@@ -102,88 +107,90 @@ var testCasesNixos = []sealTestCase{
 			Bind("/run/wrappers", "/run/wrappers", false, true).
 			Bind("/run/zed.pid", "/run/zed.pid", false, true).
 			Bind("/run/zed.state", "/run/zed.state", false, true).
-			Symlink("/dev/fortify/etc/alsa", "/etc/alsa").
+			Bind("/etc", "/fortify/etc").
-			Symlink("/dev/fortify/etc/bashrc", "/etc/bashrc").
+			Symlink("/fortify/etc/alsa", "/etc/alsa").
-			Symlink("/dev/fortify/etc/binfmt.d", "/etc/binfmt.d").
+			Symlink("/fortify/etc/bashrc", "/etc/bashrc").
-			Symlink("/dev/fortify/etc/dbus-1", "/etc/dbus-1").
+			Symlink("/fortify/etc/binfmt.d", "/etc/binfmt.d").
-			Symlink("/dev/fortify/etc/default", "/etc/default").
+			Symlink("/fortify/etc/dbus-1", "/etc/dbus-1").
-			Symlink("/dev/fortify/etc/ethertypes", "/etc/ethertypes").
+			Symlink("/fortify/etc/default", "/etc/default").
-			Symlink("/dev/fortify/etc/fonts", "/etc/fonts").
+			Symlink("/fortify/etc/ethertypes", "/etc/ethertypes").
-			Symlink("/dev/fortify/etc/fstab", "/etc/fstab").
+			Symlink("/fortify/etc/fonts", "/etc/fonts").
-			Symlink("/dev/fortify/etc/fuse.conf", "/etc/fuse.conf").
+			Symlink("/fortify/etc/fstab", "/etc/fstab").
-			Symlink("/dev/fortify/etc/host.conf", "/etc/host.conf").
+			Symlink("/fortify/etc/fuse.conf", "/etc/fuse.conf").
-			Symlink("/dev/fortify/etc/hostid", "/etc/hostid").
+			Symlink("/fortify/etc/host.conf", "/etc/host.conf").
-			Symlink("/dev/fortify/etc/hostname", "/etc/hostname").
+			Symlink("/fortify/etc/hostid", "/etc/hostid").
-			Symlink("/dev/fortify/etc/hostname.CHECKSUM", "/etc/hostname.CHECKSUM").
+			Symlink("/fortify/etc/hostname", "/etc/hostname").
-			Symlink("/dev/fortify/etc/hosts", "/etc/hosts").
+			Symlink("/fortify/etc/hostname.CHECKSUM", "/etc/hostname.CHECKSUM").
-			Symlink("/dev/fortify/etc/inputrc", "/etc/inputrc").
+			Symlink("/fortify/etc/hosts", "/etc/hosts").
-			Symlink("/dev/fortify/etc/ipsec.d", "/etc/ipsec.d").
+			Symlink("/fortify/etc/inputrc", "/etc/inputrc").
-			Symlink("/dev/fortify/etc/issue", "/etc/issue").
+			Symlink("/fortify/etc/ipsec.d", "/etc/ipsec.d").
-			Symlink("/dev/fortify/etc/kbd", "/etc/kbd").
+			Symlink("/fortify/etc/issue", "/etc/issue").
-			Symlink("/dev/fortify/etc/libblockdev", "/etc/libblockdev").
+			Symlink("/fortify/etc/kbd", "/etc/kbd").
-			Symlink("/dev/fortify/etc/locale.conf", "/etc/locale.conf").
+			Symlink("/fortify/etc/libblockdev", "/etc/libblockdev").
-			Symlink("/dev/fortify/etc/localtime", "/etc/localtime").
+			Symlink("/fortify/etc/locale.conf", "/etc/locale.conf").
-			Symlink("/dev/fortify/etc/login.defs", "/etc/login.defs").
+			Symlink("/fortify/etc/localtime", "/etc/localtime").
-			Symlink("/dev/fortify/etc/lsb-release", "/etc/lsb-release").
+			Symlink("/fortify/etc/login.defs", "/etc/login.defs").
-			Symlink("/dev/fortify/etc/lvm", "/etc/lvm").
+			Symlink("/fortify/etc/lsb-release", "/etc/lsb-release").
-			Symlink("/dev/fortify/etc/machine-id", "/etc/machine-id").
+			Symlink("/fortify/etc/lvm", "/etc/lvm").
-			Symlink("/dev/fortify/etc/man_db.conf", "/etc/man_db.conf").
+			Symlink("/fortify/etc/machine-id", "/etc/machine-id").
-			Symlink("/dev/fortify/etc/modprobe.d", "/etc/modprobe.d").
+			Symlink("/fortify/etc/man_db.conf", "/etc/man_db.conf").
-			Symlink("/dev/fortify/etc/modules-load.d", "/etc/modules-load.d").
+			Symlink("/fortify/etc/modprobe.d", "/etc/modprobe.d").
+			Symlink("/fortify/etc/modules-load.d", "/etc/modules-load.d").
 			Symlink("/proc/mounts", "/etc/mtab").
-			Symlink("/dev/fortify/etc/nanorc", "/etc/nanorc").
+			Symlink("/fortify/etc/nanorc", "/etc/nanorc").
-			Symlink("/dev/fortify/etc/netgroup", "/etc/netgroup").
+			Symlink("/fortify/etc/netgroup", "/etc/netgroup").
-			Symlink("/dev/fortify/etc/NetworkManager", "/etc/NetworkManager").
+			Symlink("/fortify/etc/NetworkManager", "/etc/NetworkManager").
-			Symlink("/dev/fortify/etc/nix", "/etc/nix").
+			Symlink("/fortify/etc/nix", "/etc/nix").
-			Symlink("/dev/fortify/etc/nixos", "/etc/nixos").
+			Symlink("/fortify/etc/nixos", "/etc/nixos").
-			Symlink("/dev/fortify/etc/NIXOS", "/etc/NIXOS").
+			Symlink("/fortify/etc/NIXOS", "/etc/NIXOS").
-			Symlink("/dev/fortify/etc/nscd.conf", "/etc/nscd.conf").
+			Symlink("/fortify/etc/nscd.conf", "/etc/nscd.conf").
-			Symlink("/dev/fortify/etc/nsswitch.conf", "/etc/nsswitch.conf").
+			Symlink("/fortify/etc/nsswitch.conf", "/etc/nsswitch.conf").
-			Symlink("/dev/fortify/etc/opensnitchd", "/etc/opensnitchd").
+			Symlink("/fortify/etc/opensnitchd", "/etc/opensnitchd").
-			Symlink("/dev/fortify/etc/os-release", "/etc/os-release").
+			Symlink("/fortify/etc/os-release", "/etc/os-release").
-			Symlink("/dev/fortify/etc/pam", "/etc/pam").
+			Symlink("/fortify/etc/pam", "/etc/pam").
-			Symlink("/dev/fortify/etc/pam.d", "/etc/pam.d").
+			Symlink("/fortify/etc/pam.d", "/etc/pam.d").
-			Symlink("/dev/fortify/etc/pipewire", "/etc/pipewire").
+			Symlink("/fortify/etc/pipewire", "/etc/pipewire").
-			Symlink("/dev/fortify/etc/pki", "/etc/pki").
+			Symlink("/fortify/etc/pki", "/etc/pki").
-			Symlink("/dev/fortify/etc/polkit-1", "/etc/polkit-1").
+			Symlink("/fortify/etc/polkit-1", "/etc/polkit-1").
-			Symlink("/dev/fortify/etc/profile", "/etc/profile").
+			Symlink("/fortify/etc/profile", "/etc/profile").
-			Symlink("/dev/fortify/etc/protocols", "/etc/protocols").
+			Symlink("/fortify/etc/protocols", "/etc/protocols").
-			Symlink("/dev/fortify/etc/qemu", "/etc/qemu").
+			Symlink("/fortify/etc/qemu", "/etc/qemu").
-			Symlink("/dev/fortify/etc/resolv.conf", "/etc/resolv.conf").
+			Symlink("/fortify/etc/resolv.conf", "/etc/resolv.conf").
-			Symlink("/dev/fortify/etc/resolvconf.conf", "/etc/resolvconf.conf").
+			Symlink("/fortify/etc/resolvconf.conf", "/etc/resolvconf.conf").
-			Symlink("/dev/fortify/etc/rpc", "/etc/rpc").
+			Symlink("/fortify/etc/rpc", "/etc/rpc").
-			Symlink("/dev/fortify/etc/samba", "/etc/samba").
+			Symlink("/fortify/etc/samba", "/etc/samba").
-			Symlink("/dev/fortify/etc/sddm.conf", "/etc/sddm.conf").
+			Symlink("/fortify/etc/sddm.conf", "/etc/sddm.conf").
-			Symlink("/dev/fortify/etc/secureboot", "/etc/secureboot").
+			Symlink("/fortify/etc/secureboot", "/etc/secureboot").
-			Symlink("/dev/fortify/etc/services", "/etc/services").
+			Symlink("/fortify/etc/services", "/etc/services").
-			Symlink("/dev/fortify/etc/set-environment", "/etc/set-environment").
+			Symlink("/fortify/etc/set-environment", "/etc/set-environment").
-			Symlink("/dev/fortify/etc/shadow", "/etc/shadow").
+			Symlink("/fortify/etc/shadow", "/etc/shadow").
-			Symlink("/dev/fortify/etc/shells", "/etc/shells").
+			Symlink("/fortify/etc/shells", "/etc/shells").
-			Symlink("/dev/fortify/etc/ssh", "/etc/ssh").
+			Symlink("/fortify/etc/ssh", "/etc/ssh").
-			Symlink("/dev/fortify/etc/ssl", "/etc/ssl").
+			Symlink("/fortify/etc/ssl", "/etc/ssl").
-			Symlink("/dev/fortify/etc/static", "/etc/static").
+			Symlink("/fortify/etc/static", "/etc/static").
-			Symlink("/dev/fortify/etc/subgid", "/etc/subgid").
+			Symlink("/fortify/etc/subgid", "/etc/subgid").
-			Symlink("/dev/fortify/etc/subuid", "/etc/subuid").
+			Symlink("/fortify/etc/subuid", "/etc/subuid").
-			Symlink("/dev/fortify/etc/sudoers", "/etc/sudoers").
+			Symlink("/fortify/etc/sudoers", "/etc/sudoers").
-			Symlink("/dev/fortify/etc/sysctl.d", "/etc/sysctl.d").
+			Symlink("/fortify/etc/sysctl.d", "/etc/sysctl.d").
-			Symlink("/dev/fortify/etc/systemd", "/etc/systemd").
+			Symlink("/fortify/etc/systemd", "/etc/systemd").
-			Symlink("/dev/fortify/etc/terminfo", "/etc/terminfo").
+			Symlink("/fortify/etc/terminfo", "/etc/terminfo").
-			Symlink("/dev/fortify/etc/tmpfiles.d", "/etc/tmpfiles.d").
+			Symlink("/fortify/etc/tmpfiles.d", "/etc/tmpfiles.d").
-			Symlink("/dev/fortify/etc/udev", "/etc/udev").
+			Symlink("/fortify/etc/udev", "/etc/udev").
-			Symlink("/dev/fortify/etc/udisks2", "/etc/udisks2").
+			Symlink("/fortify/etc/udisks2", "/etc/udisks2").
-			Symlink("/dev/fortify/etc/UPower", "/etc/UPower").
+			Symlink("/fortify/etc/UPower", "/etc/UPower").
-			Symlink("/dev/fortify/etc/vconsole.conf", "/etc/vconsole.conf").
+			Symlink("/fortify/etc/vconsole.conf", "/etc/vconsole.conf").
-			Symlink("/dev/fortify/etc/X11", "/etc/X11").
+			Symlink("/fortify/etc/X11", "/etc/X11").
-			Symlink("/dev/fortify/etc/zfs", "/etc/zfs").
+			Symlink("/fortify/etc/zfs", "/etc/zfs").
-			Symlink("/dev/fortify/etc/zinputrc", "/etc/zinputrc").
+			Symlink("/fortify/etc/zinputrc", "/etc/zinputrc").
-			Symlink("/dev/fortify/etc/zoneinfo", "/etc/zoneinfo").
+			Symlink("/fortify/etc/zoneinfo", "/etc/zoneinfo").
-			Symlink("/dev/fortify/etc/zprofile", "/etc/zprofile").
+			Symlink("/fortify/etc/zprofile", "/etc/zprofile").
-			Symlink("/dev/fortify/etc/zshenv", "/etc/zshenv").
+			Symlink("/fortify/etc/zshenv", "/etc/zshenv").
-			Symlink("/dev/fortify/etc/zshrc", "/etc/zshrc").
+			Symlink("/fortify/etc/zshrc", "/etc/zshrc").
-			Bind("/tmp/fortify.1971/tmpdir/150", "/tmp", false, true).
+			Bind("/tmp/fortify.1971/tmpdir/0", "/tmp", false, true).
 			Tmpfs("/tmp/fortify.1971", 1048576).
 			Tmpfs("/run/user", 1048576).
-			Tmpfs("/run/user/150", 8388608).
+			Tmpfs("/run/user/65534", 8388608).
+			Bind("/home/chronos", "/home/chronos", false, true).
 			Bind("/tmp/fortify.1971/4a450b6596d7bc15bd01780eb9a607ac/passwd", "/etc/passwd").
 			Bind("/tmp/fortify.1971/4a450b6596d7bc15bd01780eb9a607ac/group", "/etc/group").
 			Tmpfs("/var/run/nscd", 8192),
@@ -192,9 +199,12 @@ var testCasesNixos = []sealTestCase{
 		"nixos permissive defaults chromium", new(stubNixOS),
 		&app.Config{
 			ID:      "org.chromium.Chromium",
-			User:    "chronos",
 			Command: []string{"/run/current-system/sw/bin/zsh", "-c", "exec chromium "},
 			Confinement: app.ConfinementConfig{
+				AppID:    9,
+				Groups:   []string{"video"},
+				Username: "chronos",
+				Outer:    "/home/chronos",
 				SessionBus: &dbus.Config{
 					Talk: []string{
 						"org.freedesktop.Notifications",
@@ -228,7 +238,6 @@ var testCasesNixos = []sealTestCase{
 				},
 				Enablements: system.EWayland.Mask() | system.EDBus.Mask() | system.EPulse.Mask(),
 			},
-			Method: "systemd",
 		},
 		app.ID{
 			0xeb, 0xf0, 0x83, 0xd1,
@@ -236,11 +245,11 @@ var testCasesNixos = []sealTestCase{
 			0x82, 0xd4, 0x13, 0x36,
 			0x9b, 0x64, 0xce, 0x7c,
 		},
-		system.New(150).
+		system.New(1000009).
-			Ensure("/tmp/fortify.1971", 0701).
+			Ensure("/tmp/fortify.1971", 0711).
-			Ephemeral(system.Process, "/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c", 0701).
+			Ephemeral(system.Process, "/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c", 0711).
 			Ensure("/tmp/fortify.1971/tmpdir", 0700).UpdatePermType(system.User, "/tmp/fortify.1971/tmpdir", acl.Execute).
-			Ensure("/tmp/fortify.1971/tmpdir/150", 01700).UpdatePermType(system.User, "/tmp/fortify.1971/tmpdir/150", acl.Read, acl.Write, acl.Execute).
+			Ensure("/tmp/fortify.1971/tmpdir/9", 01700).UpdatePermType(system.User, "/tmp/fortify.1971/tmpdir/9", acl.Read, acl.Write, acl.Execute).
 			Ensure("/run/user/1971/fortify", 0700).UpdatePermType(system.User, "/run/user/1971/fortify", acl.Execute).
 			Ensure("/run/user/1971", 0700).UpdatePermType(system.User, "/run/user/1971", acl.Execute). // this is ordered as is because the previous Ensure only calls mkdir if XDG_RUNTIME_DIR is unset
 			Ephemeral(system.Process, "/run/user/1971/fortify/ebf083d1b175911782d413369b64ce7c", 0700).UpdatePermType(system.Process, "/run/user/1971/fortify/ebf083d1b175911782d413369b64ce7c", acl.Execute).
@@ -285,18 +294,19 @@ var testCasesNixos = []sealTestCase{
 		(&bwrap.Config{
 			Net:      true,
 			UserNS:   true,
+			Chdir:    "/home/chronos",
 			Clearenv: true,
 			SetEnv: map[string]string{
-				"DBUS_SESSION_BUS_ADDRESS": "unix:path=/run/user/150/bus",
+				"DBUS_SESSION_BUS_ADDRESS": "unix:path=/run/user/65534/bus",
 				"DBUS_SYSTEM_BUS_ADDRESS":  "unix:path=/run/dbus/system_bus_socket",
 				"HOME":                     "/home/chronos",
 				"PULSE_COOKIE":             "/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c/pulse-cookie",
-				"PULSE_SERVER":             "unix:/run/user/150/pulse/native",
+				"PULSE_SERVER":             "unix:/run/user/65534/pulse/native",
 				"SHELL":                    "/run/current-system/sw/bin/zsh",
 				"TERM":                     "xterm-256color",
 				"USER":                     "chronos",
-				"WAYLAND_DISPLAY":          "/run/user/150/wayland-0",
+				"WAYLAND_DISPLAY":          "/run/user/65534/wayland-0",
-				"XDG_RUNTIME_DIR":          "/run/user/150",
+				"XDG_RUNTIME_DIR":          "/run/user/65534",
 				"XDG_SESSION_CLASS":        "user",
 				"XDG_SESSION_TYPE":         "tty",
 			},
@@ -304,11 +314,11 @@ var testCasesNixos = []sealTestCase{
 			DieWithParent: true,
 			AsInit:        true,
 		}).SetUID(65534).SetGID(65534).
-			Procfs("/proc").DevTmpfs("/dev").Mqueue("/dev/mqueue").
+			Procfs("/proc").
-			Tmpfs("/dev/fortify", 4096).
+			Tmpfs("/fortify", 4096).
+			DevTmpfs("/dev").Mqueue("/dev/mqueue").
 			Bind("/bin", "/bin", false, true).
 			Bind("/boot", "/boot", false, true).
-			Bind("/etc", "/dev/fortify/etc").
 			Bind("/home", "/home", false, true).
 			Bind("/lib", "/lib", false, true).
 			Bind("/lib64", "/lib64", false, true).
@@ -353,94 +363,96 @@ var testCasesNixos = []sealTestCase{
 			Bind("/run/zed.pid", "/run/zed.pid", false, true).
 			Bind("/run/zed.state", "/run/zed.state", false, true).
 			Bind("/dev/dri", "/dev/dri", true, true, true).
-			Symlink("/dev/fortify/etc/alsa", "/etc/alsa").
+			Bind("/etc", "/fortify/etc").
-			Symlink("/dev/fortify/etc/bashrc", "/etc/bashrc").
+			Symlink("/fortify/etc/alsa", "/etc/alsa").
-			Symlink("/dev/fortify/etc/binfmt.d", "/etc/binfmt.d").
+			Symlink("/fortify/etc/bashrc", "/etc/bashrc").
-			Symlink("/dev/fortify/etc/dbus-1", "/etc/dbus-1").
+			Symlink("/fortify/etc/binfmt.d", "/etc/binfmt.d").
-			Symlink("/dev/fortify/etc/default", "/etc/default").
+			Symlink("/fortify/etc/dbus-1", "/etc/dbus-1").
-			Symlink("/dev/fortify/etc/ethertypes", "/etc/ethertypes").
+			Symlink("/fortify/etc/default", "/etc/default").
-			Symlink("/dev/fortify/etc/fonts", "/etc/fonts").
+			Symlink("/fortify/etc/ethertypes", "/etc/ethertypes").
-			Symlink("/dev/fortify/etc/fstab", "/etc/fstab").
+			Symlink("/fortify/etc/fonts", "/etc/fonts").
-			Symlink("/dev/fortify/etc/fuse.conf", "/etc/fuse.conf").
+			Symlink("/fortify/etc/fstab", "/etc/fstab").
-			Symlink("/dev/fortify/etc/host.conf", "/etc/host.conf").
+			Symlink("/fortify/etc/fuse.conf", "/etc/fuse.conf").
-			Symlink("/dev/fortify/etc/hostid", "/etc/hostid").
+			Symlink("/fortify/etc/host.conf", "/etc/host.conf").
-			Symlink("/dev/fortify/etc/hostname", "/etc/hostname").
+			Symlink("/fortify/etc/hostid", "/etc/hostid").
-			Symlink("/dev/fortify/etc/hostname.CHECKSUM", "/etc/hostname.CHECKSUM").
+			Symlink("/fortify/etc/hostname", "/etc/hostname").
-			Symlink("/dev/fortify/etc/hosts", "/etc/hosts").
+			Symlink("/fortify/etc/hostname.CHECKSUM", "/etc/hostname.CHECKSUM").
-			Symlink("/dev/fortify/etc/inputrc", "/etc/inputrc").
+			Symlink("/fortify/etc/hosts", "/etc/hosts").
-			Symlink("/dev/fortify/etc/ipsec.d", "/etc/ipsec.d").
+			Symlink("/fortify/etc/inputrc", "/etc/inputrc").
-			Symlink("/dev/fortify/etc/issue", "/etc/issue").
+			Symlink("/fortify/etc/ipsec.d", "/etc/ipsec.d").
-			Symlink("/dev/fortify/etc/kbd", "/etc/kbd").
+			Symlink("/fortify/etc/issue", "/etc/issue").
-			Symlink("/dev/fortify/etc/libblockdev", "/etc/libblockdev").
+			Symlink("/fortify/etc/kbd", "/etc/kbd").
-			Symlink("/dev/fortify/etc/locale.conf", "/etc/locale.conf").
+			Symlink("/fortify/etc/libblockdev", "/etc/libblockdev").
-			Symlink("/dev/fortify/etc/localtime", "/etc/localtime").
+			Symlink("/fortify/etc/locale.conf", "/etc/locale.conf").
-			Symlink("/dev/fortify/etc/login.defs", "/etc/login.defs").
+			Symlink("/fortify/etc/localtime", "/etc/localtime").
-			Symlink("/dev/fortify/etc/lsb-release", "/etc/lsb-release").
+			Symlink("/fortify/etc/login.defs", "/etc/login.defs").
-			Symlink("/dev/fortify/etc/lvm", "/etc/lvm").
+			Symlink("/fortify/etc/lsb-release", "/etc/lsb-release").
-			Symlink("/dev/fortify/etc/machine-id", "/etc/machine-id").
+			Symlink("/fortify/etc/lvm", "/etc/lvm").
-			Symlink("/dev/fortify/etc/man_db.conf", "/etc/man_db.conf").
+			Symlink("/fortify/etc/machine-id", "/etc/machine-id").
-			Symlink("/dev/fortify/etc/modprobe.d", "/etc/modprobe.d").
+			Symlink("/fortify/etc/man_db.conf", "/etc/man_db.conf").
-			Symlink("/dev/fortify/etc/modules-load.d", "/etc/modules-load.d").
+			Symlink("/fortify/etc/modprobe.d", "/etc/modprobe.d").
+			Symlink("/fortify/etc/modules-load.d", "/etc/modules-load.d").
 			Symlink("/proc/mounts", "/etc/mtab").
-			Symlink("/dev/fortify/etc/nanorc", "/etc/nanorc").
+			Symlink("/fortify/etc/nanorc", "/etc/nanorc").
-			Symlink("/dev/fortify/etc/netgroup", "/etc/netgroup").
+			Symlink("/fortify/etc/netgroup", "/etc/netgroup").
-			Symlink("/dev/fortify/etc/NetworkManager", "/etc/NetworkManager").
+			Symlink("/fortify/etc/NetworkManager", "/etc/NetworkManager").
-			Symlink("/dev/fortify/etc/nix", "/etc/nix").
+			Symlink("/fortify/etc/nix", "/etc/nix").
-			Symlink("/dev/fortify/etc/nixos", "/etc/nixos").
+			Symlink("/fortify/etc/nixos", "/etc/nixos").
-			Symlink("/dev/fortify/etc/NIXOS", "/etc/NIXOS").
+			Symlink("/fortify/etc/NIXOS", "/etc/NIXOS").
-			Symlink("/dev/fortify/etc/nscd.conf", "/etc/nscd.conf").
+			Symlink("/fortify/etc/nscd.conf", "/etc/nscd.conf").
-			Symlink("/dev/fortify/etc/nsswitch.conf", "/etc/nsswitch.conf").
+			Symlink("/fortify/etc/nsswitch.conf", "/etc/nsswitch.conf").
-			Symlink("/dev/fortify/etc/opensnitchd", "/etc/opensnitchd").
+			Symlink("/fortify/etc/opensnitchd", "/etc/opensnitchd").
-			Symlink("/dev/fortify/etc/os-release", "/etc/os-release").
+			Symlink("/fortify/etc/os-release", "/etc/os-release").
-			Symlink("/dev/fortify/etc/pam", "/etc/pam").
+			Symlink("/fortify/etc/pam", "/etc/pam").
-			Symlink("/dev/fortify/etc/pam.d", "/etc/pam.d").
+			Symlink("/fortify/etc/pam.d", "/etc/pam.d").
-			Symlink("/dev/fortify/etc/pipewire", "/etc/pipewire").
+			Symlink("/fortify/etc/pipewire", "/etc/pipewire").
-			Symlink("/dev/fortify/etc/pki", "/etc/pki").
+			Symlink("/fortify/etc/pki", "/etc/pki").
-			Symlink("/dev/fortify/etc/polkit-1", "/etc/polkit-1").
+			Symlink("/fortify/etc/polkit-1", "/etc/polkit-1").
-			Symlink("/dev/fortify/etc/profile", "/etc/profile").
+			Symlink("/fortify/etc/profile", "/etc/profile").
-			Symlink("/dev/fortify/etc/protocols", "/etc/protocols").
+			Symlink("/fortify/etc/protocols", "/etc/protocols").
-			Symlink("/dev/fortify/etc/qemu", "/etc/qemu").
+			Symlink("/fortify/etc/qemu", "/etc/qemu").
-			Symlink("/dev/fortify/etc/resolv.conf", "/etc/resolv.conf").
+			Symlink("/fortify/etc/resolv.conf", "/etc/resolv.conf").
-			Symlink("/dev/fortify/etc/resolvconf.conf", "/etc/resolvconf.conf").
+			Symlink("/fortify/etc/resolvconf.conf", "/etc/resolvconf.conf").
-			Symlink("/dev/fortify/etc/rpc", "/etc/rpc").
+			Symlink("/fortify/etc/rpc", "/etc/rpc").
-			Symlink("/dev/fortify/etc/samba", "/etc/samba").
+			Symlink("/fortify/etc/samba", "/etc/samba").
-			Symlink("/dev/fortify/etc/sddm.conf", "/etc/sddm.conf").
+			Symlink("/fortify/etc/sddm.conf", "/etc/sddm.conf").
-			Symlink("/dev/fortify/etc/secureboot", "/etc/secureboot").
+			Symlink("/fortify/etc/secureboot", "/etc/secureboot").
-			Symlink("/dev/fortify/etc/services", "/etc/services").
+			Symlink("/fortify/etc/services", "/etc/services").
-			Symlink("/dev/fortify/etc/set-environment", "/etc/set-environment").
+			Symlink("/fortify/etc/set-environment", "/etc/set-environment").
-			Symlink("/dev/fortify/etc/shadow", "/etc/shadow").
+			Symlink("/fortify/etc/shadow", "/etc/shadow").
-			Symlink("/dev/fortify/etc/shells", "/etc/shells").
+			Symlink("/fortify/etc/shells", "/etc/shells").
-			Symlink("/dev/fortify/etc/ssh", "/etc/ssh").
+			Symlink("/fortify/etc/ssh", "/etc/ssh").
-			Symlink("/dev/fortify/etc/ssl", "/etc/ssl").
+			Symlink("/fortify/etc/ssl", "/etc/ssl").
-			Symlink("/dev/fortify/etc/static", "/etc/static").
+			Symlink("/fortify/etc/static", "/etc/static").
-			Symlink("/dev/fortify/etc/subgid", "/etc/subgid").
+			Symlink("/fortify/etc/subgid", "/etc/subgid").
-			Symlink("/dev/fortify/etc/subuid", "/etc/subuid").
+			Symlink("/fortify/etc/subuid", "/etc/subuid").
-			Symlink("/dev/fortify/etc/sudoers", "/etc/sudoers").
+			Symlink("/fortify/etc/sudoers", "/etc/sudoers").
-			Symlink("/dev/fortify/etc/sysctl.d", "/etc/sysctl.d").
+			Symlink("/fortify/etc/sysctl.d", "/etc/sysctl.d").
-			Symlink("/dev/fortify/etc/systemd", "/etc/systemd").
+			Symlink("/fortify/etc/systemd", "/etc/systemd").
-			Symlink("/dev/fortify/etc/terminfo", "/etc/terminfo").
+			Symlink("/fortify/etc/terminfo", "/etc/terminfo").
-			Symlink("/dev/fortify/etc/tmpfiles.d", "/etc/tmpfiles.d").
+			Symlink("/fortify/etc/tmpfiles.d", "/etc/tmpfiles.d").
-			Symlink("/dev/fortify/etc/udev", "/etc/udev").
+			Symlink("/fortify/etc/udev", "/etc/udev").
-			Symlink("/dev/fortify/etc/udisks2", "/etc/udisks2").
+			Symlink("/fortify/etc/udisks2", "/etc/udisks2").
-			Symlink("/dev/fortify/etc/UPower", "/etc/UPower").
+			Symlink("/fortify/etc/UPower", "/etc/UPower").
-			Symlink("/dev/fortify/etc/vconsole.conf", "/etc/vconsole.conf").
+			Symlink("/fortify/etc/vconsole.conf", "/etc/vconsole.conf").
-			Symlink("/dev/fortify/etc/X11", "/etc/X11").
+			Symlink("/fortify/etc/X11", "/etc/X11").
-			Symlink("/dev/fortify/etc/zfs", "/etc/zfs").
+			Symlink("/fortify/etc/zfs", "/etc/zfs").
-			Symlink("/dev/fortify/etc/zinputrc", "/etc/zinputrc").
+			Symlink("/fortify/etc/zinputrc", "/etc/zinputrc").
-			Symlink("/dev/fortify/etc/zoneinfo", "/etc/zoneinfo").
+			Symlink("/fortify/etc/zoneinfo", "/etc/zoneinfo").
-			Symlink("/dev/fortify/etc/zprofile", "/etc/zprofile").
+			Symlink("/fortify/etc/zprofile", "/etc/zprofile").
-			Symlink("/dev/fortify/etc/zshenv", "/etc/zshenv").
+			Symlink("/fortify/etc/zshenv", "/etc/zshenv").
-			Symlink("/dev/fortify/etc/zshrc", "/etc/zshrc").
+			Symlink("/fortify/etc/zshrc", "/etc/zshrc").
-			Bind("/tmp/fortify.1971/tmpdir/150", "/tmp", false, true).
+			Bind("/tmp/fortify.1971/tmpdir/9", "/tmp", false, true).
 			Tmpfs("/tmp/fortify.1971", 1048576).
 			Tmpfs("/run/user", 1048576).
-			Tmpfs("/run/user/150", 8388608).
+			Tmpfs("/run/user/65534", 8388608).
+			Bind("/home/chronos", "/home/chronos", false, true).
 			Bind("/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c/passwd", "/etc/passwd").
 			Bind("/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c/group", "/etc/group").
-			Bind("/run/user/1971/fortify/ebf083d1b175911782d413369b64ce7c/wayland", "/run/user/150/wayland-0").
+			Bind("/run/user/1971/fortify/ebf083d1b175911782d413369b64ce7c/wayland", "/run/user/65534/wayland-0").
-			Bind("/run/user/1971/fortify/ebf083d1b175911782d413369b64ce7c/pulse", "/run/user/150/pulse/native").
+			Bind("/run/user/1971/fortify/ebf083d1b175911782d413369b64ce7c/pulse", "/run/user/65534/pulse/native").
 			Bind("/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c/pulse-cookie", "/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c/pulse-cookie").
-			Bind("/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c/bus", "/run/user/150/bus").
+			Bind("/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c/bus", "/run/user/65534/bus").
 			Bind("/tmp/fortify.1971/ebf083d1b175911782d413369b64ce7c/system_bus_socket", "/run/dbus/system_bus_socket").
 			Tmpfs("/var/run/nscd", 8192),
 	},
@@ -501,23 +513,12 @@ func (s *stubNixOS) Executable() (string, error) {
 	return "/home/ophestra/.nix-profile/bin/fortify", nil
 }
 
-func (s *stubNixOS) Lookup(username string) (*user.User, error) {
+func (s *stubNixOS) LookupGroup(name string) (*user.Group, error) {
-	if s.usernameErr != nil {
+	switch name {
-		if err, ok := s.usernameErr[username]; ok {
+	case "video":
-			return nil, err
+		return &user.Group{Gid: "26", Name: "video"}, nil
-		}
-	}
-
-	switch username {
-	case "chronos":
-		return &user.User{
-			Uid:      "150",
-			Gid:      "101",
-			Username: "chronos",
-			HomeDir:  "/home/chronos",
-		}, nil
 	default:
-		return nil, user.UnknownUserError(username)
+		return nil, user.UnknownGroupError(name)
 	}
 }
 
@@ -579,14 +580,22 @@ func (s *stubNixOS) Exit(code int) {
 	panic("called exit on stub with code " + strconv.Itoa(code))
 }
 
-func (s *stubNixOS) Paths() internal.Paths {
+func (s *stubNixOS) Stdout() io.Writer {
-	return internal.Paths{
+	panic("requested stdout")
+}
+
+func (s *stubNixOS) Paths() linux.Paths {
+	return linux.Paths{
 		SharePath:   "/tmp/fortify.1971",
 		RuntimePath: "/run/user/1971",
 		RunDirPath:  "/run/user/1971/fortify",
 	}
 }
 
+func (s *stubNixOS) Uid(aid int) (int, error) {
+	return 1000000 + 0*10000 + aid, nil
+}
+
 func (s *stubNixOS) SdBooted() bool {
 	return true
 }

internal/app/app_test.go

@@ -7,14 +7,14 @@ import (
 	"time"
 
 	"git.ophivana.moe/security/fortify/helper/bwrap"
-	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/app"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
 type sealTestCase struct {
 	name      string
-	os        internal.System
+	os        linux.System
 	config    *app.Config
 	id        app.ID
 	wantSys   *system.I

internal/app/config.go

@@ -1,23 +1,22 @@
 package app
 
 import (
-	"os"
+	"errors"
 
 	"git.ophivana.moe/security/fortify/dbus"
 	"git.ophivana.moe/security/fortify/helper/bwrap"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
+const fTmp = "/fortify"
+
 // Config is used to seal an *App
 type Config struct {
 	// D-Bus application ID
 	ID string `json:"id"`
-	// username of the target user to switch to
-	User string `json:"user"`
 	// value passed through to the child process as its argv
 	Command []string `json:"command"`
-	// string representation of the child's launch method
-	Method string `json:"method"`
 
 	// child confinement configuration
 	Confinement ConfinementConfig `json:"confinement"`
@@ -25,6 +24,16 @@ type Config struct {
 
 // ConfinementConfig defines fortified child's confinement
 type ConfinementConfig struct {
+	// numerical application id, determines uid in the init namespace
+	AppID int `json:"app_id"`
+	// list of supplementary groups to inherit
+	Groups []string `json:"groups"`
+	// passwd username in the sandbox, defaults to chronos
+	Username string `json:"username,omitempty"`
+	// home directory in sandbox, empty for outer
+	Inner string `json:"home_inner"`
+	// home directory in init namespace
+	Outer string `json:"home"`
 	// bwrap sandbox confinement configuration
 	Sandbox *SandboxConfig `json:"sandbox"`
 
@@ -47,8 +56,12 @@ type SandboxConfig struct {
 	UserNS bool `json:"userns,omitempty"`
 	// share net namespace
 	Net bool `json:"net,omitempty"`
+	// share all devices
+	Dev bool `json:"dev,omitempty"`
 	// do not run in new session
 	NoNewSession bool `json:"no_new_session,omitempty"`
+	// map target user uid to privileged user uid in the user namespace
+	MapRealUID bool `json:"map_real_uid"`
 	// mediated access to wayland socket
 	Wayland bool `json:"wayland,omitempty"`
 
@@ -58,6 +71,8 @@ type SandboxConfig struct {
 	Filesystem []*FilesystemConfig `json:"filesystem"`
 	// symlinks created inside the sandbox
 	Link [][2]string `json:"symlink"`
+	// automatically set up /etc symlinks
+	AutoEtc bool `json:"auto_etc"`
 	// paths to override by mounting tmpfs over them
 	Override []string `json:"override"`
 }
@@ -77,9 +92,16 @@ type FilesystemConfig struct {
 
 // Bwrap returns the address of the corresponding bwrap.Config to s.
 // Note that remaining tmpfs entries must be queued by the caller prior to launch.
-func (s *SandboxConfig) Bwrap() *bwrap.Config {
+func (s *SandboxConfig) Bwrap(os linux.System) (*bwrap.Config, error) {
 	if s == nil {
-		return nil
+		return nil, errors.New("nil sandbox config")
+	}
+
+	var uid int
+	if !s.MapRealUID {
+		uid = 65534
+	} else {
+		uid = os.Geteuid()
 	}
 
 	conf := (&bwrap.Config{
@@ -93,11 +115,21 @@ func (s *SandboxConfig) Bwrap() *bwrap.Config {
 		AsInit:        true,
 
 		// initialise map
-		Chmod: make(map[string]os.FileMode),
+		Chmod: make(bwrap.ChmodConfig),
 	}).
-		SetUID(65534).SetGID(65534).
+		SetUID(uid).SetGID(uid).
-		Procfs("/proc").DevTmpfs("/dev").Mqueue("/dev/mqueue").
+		Procfs("/proc").
-		Tmpfs("/dev/fortify", 4*1024)
+		Tmpfs(fTmp, 4*1024)
+
+	if !s.Dev {
+		conf.DevTmpfs("/dev").Mqueue("/dev/mqueue")
+	} else {
+		conf.Bind("/dev", "/dev", false, true, true)
+	}
+
+	if !s.AutoEtc {
+		conf.Dir("/etc")
+	}
 
 	for _, c := range s.Filesystem {
 		if c == nil {
@@ -115,14 +147,35 @@ func (s *SandboxConfig) Bwrap() *bwrap.Config {
 		conf.Symlink(l[0], l[1])
 	}
 
-	return conf
+	if s.AutoEtc {
+		conf.Bind("/etc", fTmp+"/etc")
+
+		// link host /etc contents to prevent passwd/group from being overwritten
+		if d, err := os.ReadDir("/etc"); err != nil {
+			return nil, err
+		} else {
+			for _, ent := range d {
+				name := ent.Name()
+				switch name {
+				case "passwd":
+				case "group":
+
+				case "mtab":
+					conf.Symlink("/proc/mounts", "/etc/"+name)
+				default:
+					conf.Symlink(fTmp+"/etc/"+name, "/etc/"+name)
+				}
+			}
+		}
+	}
+
+	return conf, nil
 }
 
 // Template returns a fully populated instance of Config.
 func Template() *Config {
 	return &Config{
 		ID: "org.chromium.Chromium",
-		User: "chronos",
 		Command: []string{
 			"chromium",
 			"--ignore-gpu-blocklist",
@@ -130,13 +183,19 @@ func Template() *Config {
 			"--enable-features=UseOzonePlatform",
 			"--ozone-platform=wayland",
 		},
-		Method: "sudo",
 		Confinement: ConfinementConfig{
+			AppID:    9,
+			Groups:   []string{"video"},
+			Username: "chronos",
+			Outer:    "/var/lib/persist/home/org.chromium.Chromium",
+			Inner:    "/var/lib/fortify",
 			Sandbox: &SandboxConfig{
 				Hostname:     "localhost",
 				UserNS:       true,
 				Net:          true,
 				NoNewSession: true,
+				MapRealUID:   true,
+				Dev:          true,
 				Wayland:      false,
 				// example API credentials pulled from Google Chrome
 				// DO NOT USE THESE IN A REAL BROWSER
@@ -146,12 +205,15 @@ func Template() *Config {
 					"GOOGLE_DEFAULT_CLIENT_SECRET": "OTJgUOQcT7lO7GsGZq2G4IlT",
 				},
 				Filesystem: []*FilesystemConfig{
-					{Src: "/nix"},
+					{Src: "/nix/store"},
-					{Src: "/storage/emulated/0", Write: true, Must: true},
+					{Src: "/run/current-system"},
-					{Src: "/data/user/0", Dst: "/data/data", Write: true, Must: true},
+					{Src: "/run/opengl-driver"},
-					{Src: "/var/tmp", Write: true},
+					{Src: "/var/db/nix-channels"},
+					{Src: "/home/chronos", Write: true, Must: true},
+					{Src: "/dev/dri", Device: true},
 				},
-				Link:     [][2]string{{"/dev/fortify/etc", "/etc"}},
+				Link:     [][2]string{{"/run/user/65534", "/run/user/150"}},
+				AutoEtc:  true,
 				Override: []string{"/var/run/nscd"},
 			},
 			SystemBus: &dbus.Config{

internal/app/export_test.go

@@ -2,11 +2,11 @@ package app
 
 import (
 	"git.ophivana.moe/security/fortify/helper/bwrap"
-	"git.ophivana.moe/security/fortify/internal"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
-func NewWithID(id ID, os internal.System) App {
+func NewWithID(id ID, os linux.System) App {
 	a := new(app)
 	a.id = &id
 	a.os = os

internal/app/launch.machinectl.go

@@ -1,57 +0,0 @@
-package app
-
-import (
-	"strings"
-
-	"git.ophivana.moe/security/fortify/internal/fmsg"
-)
-
-func (a *app) commandBuilderMachineCtl(shimEnv string) (args []string) {
-	args = make([]string, 0, 9+len(a.seal.sys.bwrap.SetEnv))
-
-	// shell --uid=$USER
-	args = append(args, "shell", "--uid="+a.seal.sys.user.Username)
-
-	// --quiet
-	if !fmsg.Verbose() {
-		args = append(args, "--quiet")
-	}
-
-	// environ
-	envQ := make([]string, 0, len(a.seal.sys.bwrap.SetEnv)+1)
-	for k, v := range a.seal.sys.bwrap.SetEnv {
-		envQ = append(envQ, "-E"+k+"="+v)
-	}
-	// add shim payload to environment for shim path
-	envQ = append(envQ, "-E"+shimEnv)
-	args = append(args, envQ...)
-
-	// -- .host
-	args = append(args, "--", ".host")
-
-	// /bin/sh -c
-	if sh, err := a.os.LookPath("sh"); err != nil {
-		// hardcode /bin/sh path since it exists more often than not
-		args = append(args, "/bin/sh", "-c")
-	} else {
-		args = append(args, sh, "-c")
-	}
-
-	// build inner command expression ran as target user
-	innerCommand := strings.Builder{}
-
-	// apply custom environment variables to activation environment
-	innerCommand.WriteString("dbus-update-activation-environment --systemd")
-	for k := range a.seal.sys.bwrap.SetEnv {
-		innerCommand.WriteString(" " + k)
-	}
-	innerCommand.WriteString("; ")
-
-	// launch fortify as shim
-	innerCommand.WriteString("exec " + a.seal.sys.executable + " shim")
-
-	// append inner command
-	args = append(args, innerCommand.String())
-
-	return
-}

internal/app/launch.sudo.go

@@ -1,30 +0,0 @@
-package app
-
-import (
-	"git.ophivana.moe/security/fortify/internal/fmsg"
-)
-
-const (
-	sudoAskPass = "SUDO_ASKPASS"
-)
-
-func (a *app) commandBuilderSudo(shimEnv string) (args []string) {
-	args = make([]string, 0, 8)
-
-	// -Hiu $USER
-	args = append(args, "-Hiu", a.seal.sys.user.Username)
-
-	// -A?
-	if _, ok := a.os.LookupEnv(sudoAskPass); ok {
-		fmsg.VPrintln(sudoAskPass, "set, adding askpass flag")
-		args = append(args, "-A")
-	}
-
-	// shim payload
-	args = append(args, shimEnv)
-
-	// -- $@
-	args = append(args, "--", a.seal.sys.executable, "shim")
-
-	return
-}

internal/app/seal.go

@@ -2,45 +2,37 @@ package app
 
 import (
 	"errors"
+	"fmt"
 	"io/fs"
-	"os/user"
 	"path"
+	"regexp"
 	"strconv"
 
+	shim "git.ophivana.moe/security/fortify/cmd/fshim/ipc"
 	"git.ophivana.moe/security/fortify/dbus"
-	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
-	"git.ophivana.moe/security/fortify/internal/shim"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/state"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
-const (
-	LaunchMethodSudo uint8 = iota
-	LaunchMethodMachineCtl
-)
-
-var method = [...]string{
-	LaunchMethodSudo:       "sudo",
-	LaunchMethodMachineCtl: "systemd",
-}
-
 var (
 	ErrConfig = errors.New("no configuration to seal")
-	ErrUser   = errors.New("unknown user")
+	ErrUser   = errors.New("invalid aid")
-	ErrLaunch = errors.New("invalid launch method")
+	ErrHome   = errors.New("invalid home directory")
-
+	ErrName   = errors.New("invalid username")
-	ErrSudo       = errors.New("sudo not available")
-	ErrSystemd    = errors.New("systemd not available")
-	ErrMachineCtl = errors.New("machinectl not available")
 )
 
+var posixUsername = regexp.MustCompilePOSIX("^[a-z_]([A-Za-z0-9_-]{0,31}|[A-Za-z0-9_-]{0,30}\\$)$")
+
 // appSeal seals the application with child-related information
 type appSeal struct {
 	// app unique ID string representation
 	id string
 	// wayland mediation, disabled if nil
 	wl *shim.Wayland
+	// dbus proxy message buffer retriever
+	dbusMsg func(f func(msgbuf []string))
 
 	// freedesktop application ID
 	fid string
@@ -49,15 +41,11 @@ type appSeal struct {
 	// persistent process state store
 	store state.Store
 
-	// uint8 representation of launch method sealed from config
-	launchOption uint8
 	// process-specific share directory path
 	share string
 	// process-specific share directory path local to XDG_RUNTIME_DIR
 	shareLocal string
 
-	// path to launcher program
-	toolPath string
 	// pass-through enablement tracking from config
 	et system.Enablements
 
@@ -66,7 +54,7 @@ type appSeal struct {
 	// seal system-level component
 	sys *appSealSys
 
-	internal.Paths
+	linux.Paths
 
 	// protected by upstream mutex
 }
@@ -96,55 +84,63 @@ func (a *app) Seal(config *Config) error {
 	seal.fid = config.ID
 	seal.command = config.Command
 
-	// parses launch method text and looks up tool path
-	switch config.Method {
-	case method[LaunchMethodSudo]:
-		seal.launchOption = LaunchMethodSudo
-		if sudoPath, err := a.os.LookPath("sudo"); err != nil {
-			return fmsg.WrapError(ErrSudo,
-				"sudo not found")
-		} else {
-			seal.toolPath = sudoPath
-		}
-	case method[LaunchMethodMachineCtl]:
-		seal.launchOption = LaunchMethodMachineCtl
-		if !a.os.SdBooted() {
-			return fmsg.WrapError(ErrSystemd,
-				"system has not been booted with systemd as init system")
-		}
-
-		if machineCtlPath, err := a.os.LookPath("machinectl"); err != nil {
-			return fmsg.WrapError(ErrMachineCtl,
-				"machinectl not found")
-		} else {
-			seal.toolPath = machineCtlPath
-		}
-	default:
-		return fmsg.WrapError(ErrLaunch,
-			"invalid launch method")
-	}
-
 	// create seal system component
 	seal.sys = new(appSealSys)
 
-	// look up fortify executable path
+	// mapped uid
-	if p, err := a.os.Executable(); err != nil {
+	if config.Confinement.Sandbox != nil && config.Confinement.Sandbox.MapRealUID {
-		return fmsg.WrapErrorSuffix(err, "cannot look up fortify executable path:")
+		seal.sys.mappedID = a.os.Geteuid()
 	} else {
-		seal.sys.executable = p
+		seal.sys.mappedID = 65534
+	}
+	seal.sys.mappedIDString = strconv.Itoa(seal.sys.mappedID)
+	seal.sys.runtime = path.Join("/run/user", seal.sys.mappedIDString)
+
+	// validate uid and set user info
+	if config.Confinement.AppID < 0 || config.Confinement.AppID > 9999 {
+		return fmsg.WrapError(ErrUser,
+			fmt.Sprintf("aid %d out of range", config.Confinement.AppID))
+	} else {
+		seal.sys.user = appUser{
+			aid:      config.Confinement.AppID,
+			as:       strconv.Itoa(config.Confinement.AppID),
+			data:     config.Confinement.Outer,
+			home:     config.Confinement.Inner,
+			username: config.Confinement.Username,
+		}
+		if seal.sys.user.username == "" {
+			seal.sys.user.username = "chronos"
+		} else if !posixUsername.MatchString(seal.sys.user.username) {
+			return fmsg.WrapError(ErrName,
+				fmt.Sprintf("invalid user name %q", seal.sys.user.username))
+		}
+		if seal.sys.user.data == "" || !path.IsAbs(seal.sys.user.data) {
+			return fmsg.WrapError(ErrHome,
+				fmt.Sprintf("invalid home directory %q", seal.sys.user.data))
+		}
+		if seal.sys.user.home == "" {
+			seal.sys.user.home = seal.sys.user.data
 		}
 
-	// look up user from system
+		// invoke fsu for full uid
-	if u, err := a.os.Lookup(config.User); err != nil {
+		if u, err := a.os.Uid(seal.sys.user.aid); err != nil {
-		if errors.As(err, new(user.UnknownUserError)) {
+			return fmsg.WrapErrorSuffix(err,
-			return fmsg.WrapError(ErrUser, "unknown user", config.User)
+				"cannot obtain uid from fsu:")
 		} else {
-			// unreachable
+			seal.sys.user.uid = u
-			panic(err)
+			seal.sys.user.us = strconv.Itoa(u)
 		}
+
+		// resolve supplementary group ids from names
+		seal.sys.user.supp = make([]string, len(config.Confinement.Groups))
+		for i, name := range config.Confinement.Groups {
+			if g, err := a.os.LookupGroup(name); err != nil {
+				return fmsg.WrapError(err,
+					fmt.Sprintf("unknown group %q", name))
 			} else {
-		seal.sys.user = u
+				seal.sys.user.supp[i] = g.Gid
-		seal.sys.runtime = path.Join("/run/user", u.Uid)
+			}
+		}
 	}
 
 	// map sandbox config to bwrap
@@ -156,6 +152,7 @@ func (a *app) Seal(config *Config) error {
 			UserNS:       true,
 			Net:          true,
 			NoNewSession: true,
+			AutoEtc:      true,
 		}
 		// bind entries in /
 		if d, err := a.os.ReadDir("/"); err != nil {
@@ -170,9 +167,8 @@ func (a *app) Seal(config *Config) error {
 				case "/run":
 				case "/tmp":
 				case "/mnt":
-
 				case "/etc":
-					b = append(b, &FilesystemConfig{Src: p, Dst: "/dev/fortify/etc", Write: false, Must: true})
+
 				default:
 					b = append(b, &FilesystemConfig{Src: p, Write: true, Must: true})
 				}
@@ -205,35 +201,14 @@ func (a *app) Seal(config *Config) error {
 		if config.Confinement.Enablements.Has(system.EX11) || config.Confinement.Enablements.Has(system.EWayland) {
 			conf.Filesystem = append(conf.Filesystem, &FilesystemConfig{Src: "/dev/dri", Device: true})
 		}
-		// link host /etc to prevent passwd/group from being overwritten
-		if d, err := a.os.ReadDir("/etc"); err != nil {
-			return err
-		} else {
-			b := make([][2]string, 0, len(d))
-			for _, ent := range d {
-				name := ent.Name()
-				switch name {
-				case "passwd":
-				case "group":
-
-				case "mtab":
-					b = append(b, [2]string{
-						"/proc/mounts",
-						"/etc/" + name,
-					})
-				default:
-					b = append(b, [2]string{
-						"/dev/fortify/etc/" + name,
-						"/etc/" + name,
-					})
-				}
-			}
-			conf.Link = append(conf.Link, b...)
-		}
 
 		config.Confinement.Sandbox = conf
 	}
-	seal.sys.bwrap = config.Confinement.Sandbox.Bwrap()
+	if b, err := config.Confinement.Sandbox.Bwrap(a.os); err != nil {
+		return err
+	} else {
+		seal.sys.bwrap = b
+	}
 	seal.sys.override = config.Confinement.Sandbox.Override
 	if seal.sys.bwrap.SetEnv == nil {
 		seal.sys.bwrap.SetEnv = make(map[string]string)
@@ -248,15 +223,10 @@ func (a *app) Seal(config *Config) error {
 	// open process state store
 	// the simple store only starts holding an open file after first action
 	// store activity begins after Start is called and must end before Wait
-	seal.store = state.NewSimple(seal.RunDirPath, seal.sys.user.Uid)
+	seal.store = state.NewSimple(seal.RunDirPath, seal.sys.user.as)
 
-	// parse string UID
+	// initialise system interface with full uid
-	if u, err := strconv.Atoi(seal.sys.user.Uid); err != nil {
+	seal.sys.I = system.New(seal.sys.user.uid)
-		// unreachable unless kernel bug
-		panic("uid parse")
-	} else {
-		seal.sys.I = system.New(u)
-	}
 
 	// pass through enablements
 	seal.et = config.Confinement.Enablements
@@ -267,11 +237,8 @@ func (a *app) Seal(config *Config) error {
 	}
 
 	// verbose log seal information
-	fmsg.VPrintln("created application seal as user",
+	fmsg.VPrintf("created application seal for uid %s (%s) groups: %v, command: %s",
-		seal.sys.user.Username, "("+seal.sys.user.Uid+"),",
+		seal.sys.user.us, seal.sys.user.username, config.Confinement.Groups, config.Command)
-		"method:", config.Method+",",
-		"launcher:", seal.toolPath+",",
-		"command:", config.Command)
 
 	// seal app and release lock
 	a.seal = seal

internal/app/share.dbus.go

@@ -22,8 +22,10 @@ func (seal *appSeal) shareDBus(config [2]*dbus.Config) error {
 	sessionPath, systemPath := path.Join(seal.share, "bus"), path.Join(seal.share, "system_bus_socket")
 
 	// configure dbus proxy
-	if err := seal.sys.ProxyDBus(config[0], config[1], sessionPath, systemPath); err != nil {
+	if f, err := seal.sys.ProxyDBus(config[0], config[1], sessionPath, systemPath); err != nil {
 		return err
+	} else {
+		seal.dbusMsg = f
 	}
 
 	// share proxy sockets

internal/app/share.display.go

@@ -5,8 +5,8 @@ import (
 	"path"
 
 	"git.ophivana.moe/security/fortify/acl"
-	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
@@ -23,7 +23,7 @@ var (
 	ErrXDisplay = errors.New(display + " unset")
 )
 
-func (seal *appSeal) shareDisplay(os internal.System) error {
+func (seal *appSeal) shareDisplay(os linux.System) error {
 	// pass $TERM to launcher
 	if t, ok := os.LookupEnv(term); ok {
 		seal.sys.bwrap.SetEnv[term] = t
@@ -58,7 +58,7 @@ func (seal *appSeal) shareDisplay(os internal.System) error {
 			return fmsg.WrapError(ErrXDisplay,
 				"DISPLAY is not set")
 		} else {
-			seal.sys.ChangeHosts(seal.sys.user.Username)
+			seal.sys.ChangeHosts("#" + seal.sys.user.us)
 			seal.sys.bwrap.SetEnv[display] = d
 			seal.sys.bwrap.Bind("/tmp/.X11-unix", "/tmp/.X11-unix")
 		}

internal/app/share.pulse.go

@@ -6,8 +6,8 @@ import (
 	"io/fs"
 	"path"
 
-	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
@@ -25,7 +25,7 @@ var (
 	ErrPulseMode   = errors.New("unexpected pulse socket mode")
 )
 
-func (seal *appSeal) sharePulse(os internal.System) error {
+func (seal *appSeal) sharePulse(os linux.System) error {
 	if !seal.et.Has(system.EPulse) {
 		return nil
 	}
@@ -78,7 +78,7 @@ func (seal *appSeal) sharePulse(os internal.System) error {
 }
 
 // discoverPulseCookie attempts various standard methods to discover the current user's PulseAudio authentication cookie
-func discoverPulseCookie(os internal.System) (string, error) {
+func discoverPulseCookie(os linux.System) (string, error) {
 	if p, ok := os.LookupEnv(pulseCookie); ok {
 		return p, nil
 	}

internal/app/share.system.go

@@ -4,7 +4,7 @@ import (
 	"path"
 
 	"git.ophivana.moe/security/fortify/acl"
-	"git.ophivana.moe/security/fortify/internal"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
@@ -16,12 +16,12 @@ const (
 func (seal *appSeal) shareSystem() {
 	// ensure Share (e.g. `/tmp/fortify.%d`)
 	// acl is unnecessary as this directory is world executable
-	seal.sys.Ensure(seal.SharePath, 0701)
+	seal.sys.Ensure(seal.SharePath, 0711)
 
 	// ensure process-specific share (e.g. `/tmp/fortify.%d/%s`)
 	// acl is unnecessary as this directory is world executable
 	seal.share = path.Join(seal.SharePath, seal.id)
-	seal.sys.Ephemeral(system.Process, seal.share, 0701)
+	seal.sys.Ephemeral(system.Process, seal.share, 0711)
 
 	// ensure child tmpdir parent directory (e.g. `/tmp/fortify.%d/tmpdir`)
 	targetTmpdirParent := path.Join(seal.SharePath, "tmpdir")
@@ -29,7 +29,7 @@ func (seal *appSeal) shareSystem() {
 	seal.sys.UpdatePermType(system.User, targetTmpdirParent, acl.Execute)
 
 	// ensure child tmpdir (e.g. `/tmp/fortify.%d/tmpdir/%d`)
-	targetTmpdir := path.Join(targetTmpdirParent, seal.sys.user.Uid)
+	targetTmpdir := path.Join(targetTmpdirParent, seal.sys.user.as)
 	seal.sys.Ensure(targetTmpdir, 01700)
 	seal.sys.UpdatePermType(system.User, targetTmpdir, acl.Read, acl.Write, acl.Execute)
 	seal.sys.bwrap.Bind(targetTmpdir, "/tmp", false, true)
@@ -38,7 +38,7 @@ func (seal *appSeal) shareSystem() {
 	seal.sys.bwrap.Tmpfs(seal.SharePath, 1*1024*1024)
 }
 
-func (seal *appSeal) sharePasswd(os internal.System) {
+func (seal *appSeal) sharePasswd(os linux.System) {
 	// look up shell
 	sh := "/bin/sh"
 	if s, ok := os.LookupEnv(shell); ok {
@@ -49,21 +49,27 @@ func (seal *appSeal) sharePasswd(os internal.System) {
 	// generate /etc/passwd
 	passwdPath := path.Join(seal.share, "passwd")
 	username := "chronos"
-	if seal.sys.user.Username != "" {
+	if seal.sys.user.username != "" {
-		username = seal.sys.user.Username
+		username = seal.sys.user.username
-		seal.sys.bwrap.SetEnv["USER"] = seal.sys.user.Username
 	}
 	homeDir := "/var/empty"
-	if seal.sys.user.HomeDir != "" {
+	if seal.sys.user.home != "" {
-		homeDir = seal.sys.user.HomeDir
+		homeDir = seal.sys.user.home
-		seal.sys.bwrap.SetEnv["HOME"] = seal.sys.user.HomeDir
 	}
-	passwd := username + ":x:65534:65534:Fortify:" + homeDir + ":" + sh + "\n"
+
+	// bind home directory
+	seal.sys.bwrap.Bind(seal.sys.user.data, homeDir, false, true)
+	seal.sys.bwrap.Chdir = homeDir
+
+	seal.sys.bwrap.SetEnv["USER"] = username
+	seal.sys.bwrap.SetEnv["HOME"] = homeDir
+
+	passwd := username + ":x:" + seal.sys.mappedIDString + ":" + seal.sys.mappedIDString + ":Fortify:" + homeDir + ":" + sh + "\n"
 	seal.sys.Write(passwdPath, passwd)
 
 	// write /etc/group
 	groupPath := path.Join(seal.share, "group")
-	seal.sys.Write(groupPath, "fortify:x:65534:\n")
+	seal.sys.Write(groupPath, "fortify:x:"+seal.sys.mappedIDString+":\n")
 
 	// bind /etc/passwd and /etc/group
 	seal.sys.bwrap.Bind(passwdPath, "/etc/passwd")

internal/app/start.go

@@ -8,9 +8,10 @@ import (
 	"path/filepath"
 	"strings"
 
+	shim0 "git.ophivana.moe/security/fortify/cmd/fshim/ipc"
+	"git.ophivana.moe/security/fortify/cmd/fshim/ipc/shim"
 	"git.ophivana.moe/security/fortify/helper"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
-	"git.ophivana.moe/security/fortify/internal/shim"
 	"git.ophivana.moe/security/fortify/internal/state"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
@@ -22,9 +23,9 @@ func (a *app) Start() error {
 	defer a.lock.Unlock()
 
 	// resolve exec paths
-	shimExec := [3]string{a.seal.sys.executable, helper.BubblewrapName}
+	shimExec := [2]string{helper.BubblewrapName}
 	if len(a.seal.command) > 0 {
-		shimExec[2] = a.seal.command[0]
+		shimExec[1] = a.seal.command[0]
 	}
 	for i, n := range shimExec {
 		if len(n) == 0 {
@@ -40,20 +41,14 @@ func (a *app) Start() error {
 		}
 	}
 
-	// select command builder
-	var commandBuilder shim.CommandBuilder
-	switch a.seal.launchOption {
-	case LaunchMethodSudo:
-		commandBuilder = a.commandBuilderSudo
-	case LaunchMethodMachineCtl:
-		commandBuilder = a.commandBuilderMachineCtl
-	default:
-		panic("unreachable")
-	}
-
 	// construct shim manager
-	a.shim = shim.New(a.seal.toolPath, uint32(a.seal.sys.UID()), path.Join(a.seal.share, "shim"), a.seal.wl,
+	a.shim = shim.New(
-		&shim.Payload{
+		uint32(a.seal.sys.UID()),
+		a.seal.sys.user.as,
+		a.seal.sys.user.supp,
+		path.Join(a.seal.share, "shim"),
+		a.seal.wl,
+		&shim0.Payload{
 			Argv:  a.seal.command,
 			Exec:  shimExec,
 			Bwrap: a.seal.sys.bwrap,
@@ -61,9 +56,6 @@ func (a *app) Start() error {
 
 			Verbose: fmsg.Verbose(),
 		},
-		// checkPid is impossible at the moment since there is no reliable way to obtain shim's pid
-		// this feature is disabled here until sudo is replaced by fortify suid wrapper
-		false,
 	)
 
 	// startup will go ahead, commit system setup
@@ -72,7 +64,7 @@ func (a *app) Start() error {
 	}
 	a.seal.sys.needRevert = true
 
-	if startTime, err := a.shim.Start(commandBuilder); err != nil {
+	if startTime, err := a.shim.Start(); err != nil {
 		return err
 	} else {
 		// shim start and setup success, create process state
@@ -80,7 +72,6 @@ func (a *app) Start() error {
 			PID:        a.shim.Unwrap().Process.Pid,
 			Command:    a.seal.command,
 			Capability: a.seal.et,
-			Method:     method[a.seal.launchOption],
 			Argv:       a.shim.Unwrap().Args,
 			Time:       *startTime,
 		}
@@ -165,8 +156,13 @@ func (a *app) Wait() (int, error) {
 		// failure prior to process start
 		r = 255
 	} else {
+		wait := make(chan error, 1)
+		go func() { wait <- cmd.Wait() }()
+
+		select {
 		// wait for process and resolve exit code
-		if err := cmd.Wait(); err != nil {
+		case err := <-wait:
+			if err != nil {
 				var exitError *exec.ExitError
 				if !errors.As(err, &exitError) {
 					// should be unreachable
@@ -179,11 +175,30 @@ func (a *app) Wait() (int, error) {
 				r = cmd.ProcessState.ExitCode()
 			}
 			fmsg.VPrintf("process %d exited with exit code %d", cmd.Process.Pid, r)
+
+		// alternative exit path when kill was unsuccessful
+		case err := <-a.shim.WaitFallback():
+			r = 255
+			if err != nil {
+				fmsg.Printf("cannot terminate shim on faulted setup: %v", err)
+			} else {
+				fmsg.VPrintln("alternative exit path selected")
+			}
+		}
 	}
 
 	// child process exited, resume output
 	fmsg.Resume()
 
+	// print queued up dbus messages
+	if a.seal.dbusMsg != nil {
+		a.seal.dbusMsg(func(msgbuf []string) {
+			for _, msg := range msgbuf {
+				fmsg.Println(msg)
+			}
+		})
+	}
+
 	// close wayland connection
 	if a.seal.wl != nil {
 		if err := a.seal.wl.Close(); err != nil {
@@ -240,10 +255,17 @@ func (a *app) Wait() (int, error) {
 				}
 			}
 
+			if a.shim.Unwrap() == nil {
+				fmsg.VPrintln("fault before shim start")
+			} else {
 				a.shim.AbortWait(errors.New("shim exited"))
+			}
+
+			if a.seal.sys.needRevert {
 				if err := a.seal.sys.Revert(ec); err != nil {
 					return err.(RevertCompoundError)
 				}
+			}
 
 			return nil
 		}()

internal/app/system.go

@@ -1,11 +1,9 @@
 package app
 
 import (
-	"os/user"
-
 	"git.ophivana.moe/security/fortify/dbus"
 	"git.ophivana.moe/security/fortify/helper/bwrap"
-	"git.ophivana.moe/security/fortify/internal"
+	"git.ophivana.moe/security/fortify/internal/linux"
 	"git.ophivana.moe/security/fortify/internal/system"
 )
 
@@ -17,10 +15,13 @@ type appSealSys struct {
 
 	// default formatted XDG_RUNTIME_DIR of User
 	runtime string
-	// sealed path to fortify executable, used by shim
-	executable string
 	// target user sealed from config
-	user *user.User
+	user appUser
+
+	// mapped uid and gid in user namespace
+	mappedID int
+	// string representation of mappedID
+	mappedIDString string
 
 	needRevert bool
 	saveState  bool
@@ -29,8 +30,30 @@ type appSealSys struct {
 	// protected by upstream mutex
 }
 
+type appUser struct {
+	// full uid resolved by fsu
+	uid int
+	// string representation of uid
+	us string
+
+	// supplementary group ids
+	supp []string
+
+	// application id
+	aid int
+	// string representation of aid
+	as string
+
+	// home directory host path
+	data string
+	// app user home directory
+	home string
+	// passwd database username
+	username string
+}
+
 // shareAll calls all share methods in sequence
-func (seal *appSeal) shareAll(bus [2]*dbus.Config, os internal.System) error {
+func (seal *appSeal) shareAll(bus [2]*dbus.Config, os linux.System) error {
 	if seal.shared {
 		panic("seal shared twice")
 	}

internal/comp.go

@@ -0,0 +1,12 @@
+package internal
+
+const compPoison = "INVALIDINVALIDINVALIDINVALIDINVALID"
+
+var (
+	Version = compPoison
+)
+
+// Check validates string value set at compile time.
+func Check(s string) (string, bool) {
+	return s, s != compPoison && s != ""
+}

internal/fmsg/defer.go

@@ -8,6 +8,7 @@ import (
 
 var (
 	wstate   atomic.Bool
+	dropped  atomic.Uint64
 	withhold = make(chan struct{}, 1)
 	msgbuf   = make(chan dOp, 64) // these ops are tiny so a large buffer is allocated for withholding output
 
@@ -29,6 +30,26 @@ func dequeue() {
 	}()
 }
 
+// queue submits ops to msgbuf but drops messages
+// when the buffer is full and dequeue is withholding
+func queue(op dOp) {
+	queueSync.Add(1)
+
+	select {
+	case msgbuf <- op:
+	default:
+		// send the op anyway if not withholding
+		// as dequeue will get to it eventually
+		if !wstate.Load() {
+			msgbuf <- op
+		} else {
+			queueSync.Done()
+			// increment dropped message count
+			dropped.Add(1)
+		}
+	}
+}
+
 type dOp interface{ Do() }
 
 func Exit(code int) {
@@ -36,9 +57,10 @@ func Exit(code int) {
 	os.Exit(code)
 }
 
-func Withhold() {
+func Suspend() {
 	dequeueOnce.Do(dequeue)
 	if wstate.CompareAndSwap(false, true) {
+		queueSync.Wait()
 		withhold <- struct{}{}
 	}
 }
@@ -47,6 +69,9 @@ func Resume() {
 	dequeueOnce.Do(dequeue)
 	if wstate.CompareAndSwap(true, false) {
 		withhold <- struct{}{}
+		if d := dropped.Swap(0); d != 0 {
+			Printf("dropped %d messages during withhold", d)
+		}
 	}
 }
 

internal/fmsg/fmsg.go

@@ -16,20 +16,17 @@ func SetPrefix(prefix string) {
 
 func Print(v ...any) {
 	dequeueOnce.Do(dequeue)
-	queueSync.Add(1)
+	queue(dPrint(v))
-	msgbuf <- dPrint(v)
 }
 
 func Printf(format string, v ...any) {
 	dequeueOnce.Do(dequeue)
-	queueSync.Add(1)
+	queue(&dPrintf{format, v})
-	msgbuf <- &dPrintf{format, v}
 }
 
 func Println(v ...any) {
 	dequeueOnce.Do(dequeue)
-	queueSync.Add(1)
+	queue(dPrintln(v))
-	msgbuf <- dPrintln(v)
 }
 
 func Fatal(v ...any) {

internal/linux/interface.go

@@ -1,14 +1,11 @@
-package internal
+package linux
 
 import (
-	"errors"
+	"io"
 	"io/fs"
-	"os"
-	"os/exec"
 	"os/user"
 	"path"
 	"strconv"
-	"sync"
 
 	"git.ophivana.moe/security/fortify/internal/fmsg"
 )
@@ -25,8 +22,8 @@ type System interface {
 	LookPath(file string) (string, error)
 	// Executable provides [os.Executable].
 	Executable() (string, error)
-	// Lookup provides [user.Lookup].
+	// LookupGroup provides [user.LookupGroup].
-	Lookup(username string) (*user.User, error)
+	LookupGroup(name string) (*user.Group, error)
 	// ReadDir provides [os.ReadDir].
 	ReadDir(name string) ([]fs.DirEntry, error)
 	// Stat provides [os.Stat].
@@ -35,9 +32,13 @@ type System interface {
 	Open(name string) (fs.File, error)
 	// Exit provides [os.Exit].
 	Exit(code int)
+	// Stdout provides [os.Stdout].
+	Stdout() io.Writer
 
 	// Paths returns a populated [Paths] struct.
 	Paths() Paths
+	// Uid invokes fsu and returns target uid.
+	Uid(aid int) (int, error)
 	// SdBooted implements https://www.freedesktop.org/software/systemd/man/sd_booted.html
 	SdBooted() bool
 }
@@ -69,58 +70,3 @@ func CopyPaths(os System, v *Paths) {
 
 	fmsg.VPrintf("runtime directory at %q", v.RunDirPath)
 }
-
-// Std implements System using the standard library.
-type Std struct {
-	paths     Paths
-	pathsOnce sync.Once
-
-	sdBooted     bool
-	sdBootedOnce sync.Once
-}
-
-func (s *Std) Geteuid() int                               { return os.Geteuid() }
-func (s *Std) LookupEnv(key string) (string, bool)        { return os.LookupEnv(key) }
-func (s *Std) TempDir() string                            { return os.TempDir() }
-func (s *Std) LookPath(file string) (string, error)       { return exec.LookPath(file) }
-func (s *Std) Executable() (string, error)                { return os.Executable() }
-func (s *Std) Lookup(username string) (*user.User, error) { return user.Lookup(username) }
-func (s *Std) ReadDir(name string) ([]os.DirEntry, error) { return os.ReadDir(name) }
-func (s *Std) Stat(name string) (fs.FileInfo, error)      { return os.Stat(name) }
-func (s *Std) Open(name string) (fs.File, error)          { return os.Open(name) }
-func (s *Std) Exit(code int)                              { fmsg.Exit(code) }
-
-const xdgRuntimeDir = "XDG_RUNTIME_DIR"
-
-func (s *Std) Paths() Paths {
-	s.pathsOnce.Do(func() { CopyPaths(s, &s.paths) })
-	return s.paths
-}
-
-func (s *Std) SdBooted() bool {
-	s.sdBootedOnce.Do(func() { s.sdBooted = copySdBooted() })
-	return s.sdBooted
-}
-
-const systemdCheckPath = "/run/systemd/system"
-
-func copySdBooted() bool {
-	if v, err := sdBooted(); err != nil {
-		fmsg.Println("cannot read systemd marker:", err)
-		return false
-	} else {
-		return v
-	}
-}
-
-func sdBooted() (bool, error) {
-	_, err := os.Stat(systemdCheckPath)
-	if err != nil {
-		if errors.Is(err, fs.ErrNotExist) {
-			err = nil
-		}
-		return false, err
-	}
-
-	return true, nil
-}

internal/linux/std.go

@@ -0,0 +1,120 @@
+package linux
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+	"os"
+	"os/exec"
+	"os/user"
+	"strconv"
+	"sync"
+
+	"git.ophivana.moe/security/fortify/internal"
+	"git.ophivana.moe/security/fortify/internal/fmsg"
+)
+
+// Std implements System using the standard library.
+type Std struct {
+	paths     Paths
+	pathsOnce sync.Once
+
+	sdBooted     bool
+	sdBootedOnce sync.Once
+
+	uidOnce sync.Once
+	uidCopy map[int]struct {
+		uid int
+		err error
+	}
+	uidMu sync.RWMutex
+}
+
+func (s *Std) Geteuid() int                                 { return os.Geteuid() }
+func (s *Std) LookupEnv(key string) (string, bool)          { return os.LookupEnv(key) }
+func (s *Std) TempDir() string                              { return os.TempDir() }
+func (s *Std) LookPath(file string) (string, error)         { return exec.LookPath(file) }
+func (s *Std) Executable() (string, error)                  { return os.Executable() }
+func (s *Std) LookupGroup(name string) (*user.Group, error) { return user.LookupGroup(name) }
+func (s *Std) ReadDir(name string) ([]os.DirEntry, error)   { return os.ReadDir(name) }
+func (s *Std) Stat(name string) (fs.FileInfo, error)        { return os.Stat(name) }
+func (s *Std) Open(name string) (fs.File, error)            { return os.Open(name) }
+func (s *Std) Exit(code int)                                { fmsg.Exit(code) }
+func (s *Std) Stdout() io.Writer                            { return os.Stdout }
+
+const xdgRuntimeDir = "XDG_RUNTIME_DIR"
+
+func (s *Std) Paths() Paths {
+	s.pathsOnce.Do(func() { CopyPaths(s, &s.paths) })
+	return s.paths
+}
+
+func (s *Std) Uid(aid int) (int, error) {
+	s.uidOnce.Do(func() {
+		s.uidCopy = make(map[int]struct {
+			uid int
+			err error
+		})
+	})
+
+	s.uidMu.RLock()
+	if u, ok := s.uidCopy[aid]; ok {
+		s.uidMu.RUnlock()
+		return u.uid, u.err
+	}
+
+	s.uidMu.RUnlock()
+	s.uidMu.Lock()
+	defer s.uidMu.Unlock()
+
+	u := struct {
+		uid int
+		err error
+	}{}
+	defer func() { s.uidCopy[aid] = u }()
+
+	u.uid = -1
+	if fsu, ok := internal.Check(internal.Fsu); !ok {
+		fmsg.Fatal("invalid fsu path, this copy of fshim is not compiled correctly")
+		panic("unreachable")
+	} else {
+		cmd := exec.Command(fsu)
+		cmd.Path = fsu
+		cmd.Stderr = os.Stderr // pass through fatal messages
+		cmd.Env = []string{"FORTIFY_APP_ID=" + strconv.Itoa(aid)}
+		cmd.Dir = "/"
+		var p []byte
+		if p, u.err = cmd.Output(); u.err == nil {
+			u.uid, u.err = strconv.Atoi(string(p))
+		}
+		return u.uid, u.err
+	}
+}
+
+func (s *Std) SdBooted() bool {
+	s.sdBootedOnce.Do(func() { s.sdBooted = copySdBooted() })
+	return s.sdBooted
+}
+
+const systemdCheckPath = "/run/systemd/system"
+
+func copySdBooted() bool {
+	if v, err := sdBooted(); err != nil {
+		fmsg.Println("cannot read systemd marker:", err)
+		return false
+	} else {
+		return v
+	}
+}
+
+func sdBooted() (bool, error) {
+	_, err := os.Stat(systemdCheckPath)
+	if err != nil {
+		if errors.Is(err, fs.ErrNotExist) {
+			err = nil
+		}
+		return false, err
+	}
+
+	return true, nil
+}

internal/path.go

@@ -0,0 +1,12 @@
+package internal
+
+import "path"
+
+var (
+	Fsu   = compPoison
+	Finit = compPoison
+)
+
+func Path(p string) (string, bool) {
+	return p, p != compPoison && p != "" && path.IsAbs(p)
+}

internal/prctl.go

@@ -0,0 +1,20 @@
+package internal
+
+import "syscall"
+
+func PR_SET_DUMPABLE__SUID_DUMP_DISABLE() error {
+	// linux/sched/coredump.h
+	if _, _, errno := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_SET_DUMPABLE, 0, 0); errno != 0 {
+		return errno
+	}
+
+	return nil
+}
+
+func PR_SET_PDEATHSIG__SIGKILL() error {
+	if _, _, errno := syscall.AllThreadsSyscall(syscall.SYS_PRCTL, syscall.PR_SET_PDEATHSIG, uintptr(syscall.SIGKILL), 0); errno != 0 {
+		return errno
+	}
+
+	return nil
+}

internal/state/print.go

@@ -67,10 +67,10 @@ func (s *simpleStore) mustPrintLauncherState(w **tabwriter.Writer, now time.Time
 
 				// write header when initialising
 				if !fmsg.Verbose() {
-					_, _ = fmt.Fprintln(*w, "\tUID\tPID\tUptime\tEnablements\tMethod\tCommand")
+					_, _ = fmt.Fprintln(*w, "\tPID\tApp\tUptime\tEnablements\tCommand")
 				} else {
 					// argv is emitted in body when verbose
-					_, _ = fmt.Fprintln(*w, "\tUID\tPID\tArgv")
+					_, _ = fmt.Fprintln(*w, "\tPID\tApp\tArgv")
 				}
 			}
 
@@ -96,13 +96,13 @@ func (s *simpleStore) mustPrintLauncherState(w **tabwriter.Writer, now time.Time
 				}
 
 				if !fmsg.Verbose() {
-					_, _ = fmt.Fprintf(*w, "\t%s\t%d\t%s\t%s\t%s\t%s\n",
+					_, _ = fmt.Fprintf(*w, "\t%d\t%s\t%s\t%s\t%s\n",
-						s.path[len(s.path)-1], state.PID, now.Sub(state.Time).Round(time.Second).String(), strings.TrimPrefix(ets.String(), ", "), state.Method,
+						state.PID, s.path[len(s.path)-1], now.Sub(state.Time).Round(time.Second).String(), strings.TrimPrefix(ets.String(), ", "),
 						state.Command)
 				} else {
 					// emit argv instead when verbose
-					_, _ = fmt.Fprintf(*w, "\t%s\t%d\t%s\n",
+					_, _ = fmt.Fprintf(*w, "\t%d\t%s\t%s\n",
-						s.path[len(s.path)-1], state.PID, state.Argv)
+						state.PID, s.path[len(s.path)-1], state.Argv)
 				}
 			}
 

internal/state/state.go

@@ -33,8 +33,6 @@ type State struct {
 	// capability enablements applied to child
 	Capability system.Enablements
 
-	// user switch method
-	Method string
 	// full argv whe launching
 	Argv []string
 	// process start time

internal/system/dbus.go

@@ -1,8 +1,11 @@
 package system
 
 import (
+	"bytes"
 	"errors"
 	"os"
+	"strings"
+	"sync"
 
 	"git.ophivana.moe/security/fortify/dbus"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
@@ -13,14 +16,14 @@ var (
 )
 
 func (sys *I) MustProxyDBus(sessionPath string, session *dbus.Config, systemPath string, system *dbus.Config) *I {
-	if err := sys.ProxyDBus(session, system, sessionPath, systemPath); err != nil {
+	if _, err := sys.ProxyDBus(session, system, sessionPath, systemPath); err != nil {
 		panic(err.Error())
 	} else {
 		return sys
 	}
 }
 
-func (sys *I) ProxyDBus(session, system *dbus.Config, sessionPath, systemPath string) error {
+func (sys *I) ProxyDBus(session, system *dbus.Config, sessionPath, systemPath string) (func(f func(msgbuf []string)), error) {
 	d := new(DBus)
 
 	// used by waiting goroutine to notify process exit
@@ -28,7 +31,7 @@ func (sys *I) ProxyDBus(session, system *dbus.Config, sessionPath, systemPath st
 
 	// session bus is mandatory
 	if session == nil {
-		return fmsg.WrapError(ErrDBusConfig,
+		return nil, fmsg.WrapError(ErrDBusConfig,
 			"attempted to seal message bus proxy without session bus config")
 	}
 
@@ -61,13 +64,15 @@ func (sys *I) ProxyDBus(session, system *dbus.Config, sessionPath, systemPath st
 	sys.ops = append(sys.ops, d)
 
 	// seal dbus proxy
-	return fmsg.WrapErrorSuffix(d.proxy.Seal(session, system),
+	d.out = &scanToFmsg{msg: new(strings.Builder)}
+	return d.out.F, fmsg.WrapErrorSuffix(d.proxy.Seal(session, system),
 		"cannot seal message bus proxy:")
 }
 
 type DBus struct {
 	proxy *dbus.Proxy
 
+	out *scanToFmsg
 	// whether system bus proxy is enabled
 	system bool
 	// notification from goroutine waiting for dbus.Proxy
@@ -88,7 +93,7 @@ func (d *DBus) apply(_ *I) error {
 	ready := make(chan error, 1)
 
 	// background dbus proxy start
-	if err := d.proxy.Start(ready, os.Stderr, true); err != nil {
+	if err := d.proxy.Start(ready, d.out, true); err != nil {
 		return fmsg.WrapErrorSuffix(err,
 			"cannot start message bus proxy:")
 	}
@@ -164,3 +169,34 @@ func (d *DBus) Path() string {
 func (d *DBus) String() string {
 	return d.proxy.String()
 }
+
+type scanToFmsg struct {
+	msg    *strings.Builder
+	msgbuf []string
+
+	mu sync.RWMutex
+}
+
+func (s *scanToFmsg) Write(p []byte) (n int, err error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.write(p, 0)
+}
+
+func (s *scanToFmsg) write(p []byte, a int) (int, error) {
+	if i := bytes.IndexByte(p, '\n'); i == -1 {
+		n, _ := s.msg.Write(p)
+		return a + n, nil
+	} else {
+		n, _ := s.msg.Write(p[:i])
+		s.msgbuf = append(s.msgbuf, s.msg.String())
+		s.msg.Reset()
+		return s.write(p[i+1:], a+n+1)
+	}
+}
+
+func (s *scanToFmsg) F(f func(msgbuf []string)) {
+	s.mu.RLock()
+	f(s.msgbuf)
+	s.mu.RUnlock()
+}

ldd/ldd.go

@@ -1,3 +1,4 @@
+// Package ldd retrieves linker information by invoking ldd from glibc or musl and parsing its output.
 package ldd
 
 import (

license.go

@@ -1,25 +0,0 @@
-package main
-
-import (
-	_ "embed"
-	"flag"
-	"fmt"
-)
-
-var (
-	//go:embed LICENSE
-	license string
-
-	printLicense bool
-)
-
-func init() {
-	flag.BoolVar(&printLicense, "license", false, "Print license")
-}
-
-func tryLicense() {
-	if printLicense {
-		fmt.Println(license)
-		os.Exit(0)
-	}
-}

main.go

@@ -1,62 +1,289 @@
 package main
 
 import (
+	_ "embed"
+	"encoding/json"
 	"flag"
-	"syscall"
+	"fmt"
+	"os/user"
+	"strconv"
+	"strings"
+	"sync"
+	"text/tabwriter"
 
+	"git.ophivana.moe/security/fortify/dbus"
 	"git.ophivana.moe/security/fortify/internal"
 	"git.ophivana.moe/security/fortify/internal/app"
 	"git.ophivana.moe/security/fortify/internal/fmsg"
-	init0 "git.ophivana.moe/security/fortify/internal/init"
+	"git.ophivana.moe/security/fortify/internal/linux"
-	"git.ophivana.moe/security/fortify/internal/shim"
+	"git.ophivana.moe/security/fortify/internal/state"
+	"git.ophivana.moe/security/fortify/internal/system"
 )
 
 var (
 	flagVerbose bool
+
+	//go:embed LICENSE
+	license string
 )
 
 func init() {
 	flag.BoolVar(&flagVerbose, "v", false, "Verbose output")
 }
 
-var os = new(internal.Std)
+var os = new(linux.Std)
+
+type gl []string
+
+func (g *gl) String() string {
+	if g == nil {
+		return "<nil>"
+	}
+	return strings.Join(*g, " ")
+}
+
+func (g *gl) Set(v string) error {
+	*g = append(*g, v)
+	return nil
+}
 
 func main() {
-	// linux/sched/coredump.h
+	if err := internal.PR_SET_DUMPABLE__SUID_DUMP_DISABLE(); err != nil {
-	if _, _, errno := syscall.RawSyscall(syscall.SYS_PRCTL, syscall.PR_SET_DUMPABLE, 0, 0); errno != 0 {
+		fmsg.Printf("cannot set SUID_DUMP_DISABLE: %s", err)
-		fmsg.Printf("fortify: cannot set SUID_DUMP_DISABLE: %s", errno.Error())
+		// not fatal: this program runs as the privileged user
 	}
 
-	flag.Parse()
-	fmsg.SetVerbose(flagVerbose)
-
-	if os.SdBooted() {
-		fmsg.VPrintln("system booted with systemd as init system")
-	}
-
-	// shim/init early exit
-	init0.Try()
-	shim.Try()
-
-	// root check
 	if os.Geteuid() == 0 {
 		fmsg.Fatal("this program must not run as root")
 		panic("unreachable")
 	}
 
-	// version/license/template command early exit
+	flag.CommandLine.Usage = func() {
-	tryVersion()
+		fmt.Println()
-	tryLicense()
+		fmt.Println("Usage:\tfortify [-v] COMMAND [OPTIONS]")
-	tryTemplate()
+		fmt.Println()
+		fmt.Println("Commands:")
+		w := tabwriter.NewWriter(os.Stdout(), 0, 1, 4, ' ', 0)
+		commands := [][2]string{
+			{"app", "Launch app defined by the specified config file"},
+			{"run", "Configure and start a permissive default sandbox"},
+			{"ps", "List active apps and their state"},
+			{"version", "Show fortify version"},
+			{"license", "Show full license text"},
+			{"template", "Produce a config template"},
+			{"help", "Show this help message"},
+		}
+		for _, c := range commands {
+			_, _ = fmt.Fprintf(w, "\t%s\t%s\n", c[0], c[1])
+		}
+		if err := w.Flush(); err != nil {
+			fmt.Printf("fortify: cannot write command list: %v\n", err)
+		}
+		fmt.Println()
+	}
+	flag.Parse()
+	fmsg.SetVerbose(flagVerbose)
 
-	// state query command early exit
+	args := flag.Args()
-	tryState()
+	if len(args) == 0 {
+		flag.CommandLine.Usage()
+		fmsg.Exit(0)
+	}
+
+	switch args[0] {
+	case "version": // print version string
+		if v, ok := internal.Check(internal.Version); ok {
+			fmt.Println(v)
+		} else {
+			fmt.Println("impure")
+		}
+		fmsg.Exit(0)
+	case "license": // print embedded license
+		fmt.Println(license)
+		fmsg.Exit(0)
+	case "template": // print full template configuration
+		if s, err := json.MarshalIndent(app.Template(), "", "  "); err != nil {
+			fmsg.Fatalf("cannot generate template: %v", err)
+			panic("unreachable")
+		} else {
+			fmt.Println(string(s))
+		}
+		fmsg.Exit(0)
+	case "help": // print help message
+		flag.CommandLine.Usage()
+		fmsg.Exit(0)
+	case "ps": // print all state info
+		var w *tabwriter.Writer
+		state.MustPrintLauncherStateSimpleGlobal(&w, os.Paths().RunDirPath)
+		if w != nil {
+			if err := w.Flush(); err != nil {
+				fmsg.Println("cannot format output:", err)
+			}
+		} else {
+			fmt.Println("No information available")
+		}
+
+		fmsg.Exit(0)
+	case "app": // launch app from configuration file
+		if len(args) < 2 {
+			fmsg.Fatal("app requires at least 1 argument")
+		}
+
+		config := new(app.Config)
+		if f, err := os.Open(args[1]); err != nil {
+			fmsg.Fatalf("cannot access config file %q: %s", args[1], err)
+			panic("unreachable")
+		} else if err = json.NewDecoder(f).Decode(&config); err != nil {
+			fmsg.Fatalf("cannot parse config file %q: %s", args[1], err)
+			panic("unreachable")
+		}
+
+		// append extra args
+		config.Command = append(config.Command, args[2:]...)
 
 		// invoke app
+		runApp(config)
+	case "run": // run app in permissive defaults usage pattern
+		set := flag.NewFlagSet("run", flag.ExitOnError)
+
+		var (
+			dbusConfigSession string
+			dbusConfigSystem  string
+			dbusID            string
+			mpris             bool
+			dbusVerbose       bool
+
+			aid         int
+			groups      gl
+			homeDir     string
+			userName    string
+			enablements [system.ELen]bool
+		)
+
+		set.StringVar(&dbusConfigSession, "dbus-config", "builtin", "Path to D-Bus proxy config file, or \"builtin\" for defaults")
+		set.StringVar(&dbusConfigSystem, "dbus-system", "nil", "Path to system D-Bus proxy config file, or \"nil\" to disable")
+		set.StringVar(&dbusID, "dbus-id", "", "D-Bus ID of application, leave empty to disable own paths, has no effect if custom config is available")
+		set.BoolVar(&mpris, "mpris", false, "Allow owning MPRIS D-Bus path, has no effect if custom config is available")
+		set.BoolVar(&dbusVerbose, "dbus-log", false, "Force logging in the D-Bus proxy")
+
+		set.IntVar(&aid, "a", 0, "Fortify application ID")
+		set.Var(&groups, "g", "Groups inherited by the app process")
+		set.StringVar(&homeDir, "d", "os", "Application home directory")
+		set.StringVar(&userName, "u", "chronos", "Passwd name within sandbox")
+		set.BoolVar(&enablements[system.EWayland], "wayland", false, "Share Wayland socket")
+		set.BoolVar(&enablements[system.EX11], "X", false, "Share X11 socket and allow connection")
+		set.BoolVar(&enablements[system.EDBus], "dbus", false, "Proxy D-Bus connection")
+		set.BoolVar(&enablements[system.EPulse], "pulse", false, "Share PulseAudio socket and cookie")
+
+		// Ignore errors; set is set for ExitOnError.
+		_ = set.Parse(args[1:])
+
+		// initialise config from flags
+		config := &app.Config{
+			ID:      dbusID,
+			Command: set.Args(),
+		}
+
+		if aid < 0 || aid > 9999 {
+			fmsg.Fatalf("aid %d out of range", aid)
+			panic("unreachable")
+		}
+
+		// resolve home/username from os when flag is unset
+		var (
+			passwd     *user.User
+			passwdOnce sync.Once
+			passwdFunc = func() {
+				var us string
+				if uid, err := os.Uid(aid); err != nil {
+					fmsg.Fatalf("cannot obtain uid from fsu: %v", err)
+				} else {
+					us = strconv.Itoa(uid)
+				}
+
+				if u, err := user.LookupId(us); err != nil {
+					fmsg.VPrintf("cannot look up uid %s", us)
+					passwd = &user.User{
+						Uid:      us,
+						Gid:      us,
+						Username: "chronos",
+						Name:     "Fortify",
+						HomeDir:  "/var/empty",
+					}
+				} else {
+					passwd = u
+				}
+			}
+		)
+
+		if homeDir == "os" {
+			passwdOnce.Do(passwdFunc)
+			homeDir = passwd.HomeDir
+		}
+
+		if userName == "chronos" {
+			passwdOnce.Do(passwdFunc)
+			userName = passwd.Username
+		}
+
+		config.Confinement.AppID = aid
+		config.Confinement.Groups = groups
+		config.Confinement.Outer = homeDir
+		config.Confinement.Username = userName
+
+		// enablements from flags
+		for i := system.Enablement(0); i < system.Enablement(system.ELen); i++ {
+			if enablements[i] {
+				config.Confinement.Enablements.Set(i)
+			}
+		}
+
+		// parse D-Bus config file from flags if applicable
+		if enablements[system.EDBus] {
+			if dbusConfigSession == "builtin" {
+				config.Confinement.SessionBus = dbus.NewConfig(dbusID, true, mpris)
+			} else {
+				if c, err := dbus.NewConfigFromFile(dbusConfigSession); err != nil {
+					fmsg.Fatalf("cannot load session bus proxy config from %q: %s", dbusConfigSession, err)
+				} else {
+					config.Confinement.SessionBus = c
+				}
+			}
+
+			// system bus proxy is optional
+			if dbusConfigSystem != "nil" {
+				if c, err := dbus.NewConfigFromFile(dbusConfigSystem); err != nil {
+					fmsg.Fatalf("cannot load system bus proxy config from %q: %s", dbusConfigSystem, err)
+				} else {
+					config.Confinement.SystemBus = c
+				}
+			}
+
+			// override log from configuration
+			if dbusVerbose {
+				config.Confinement.SessionBus.Log = true
+				config.Confinement.SystemBus.Log = true
+			}
+		}
+
+		// invoke app
+		runApp(config)
+	default:
+		fmsg.Fatalf("%q is not a valid command", args[0])
+	}
+
+	panic("unreachable")
+}
+
+func runApp(config *app.Config) {
+	if os.SdBooted() {
+		fmsg.VPrintln("system booted with systemd as init system")
+	}
+
 	a, err := app.New(os)
 	if err != nil {
 		fmsg.Fatalf("cannot create app: %s\n", err)
-	} else if err = a.Seal(loadConfig()); err != nil {
+	} else if err = a.Seal(config); err != nil {
 		logBaseError(err, "cannot seal app:")
 		fmsg.Exit(1)
 	} else if err = a.Start(); err != nil {
@@ -75,4 +302,5 @@ func main() {
 		fmsg.Println("inner wait failed:", err)
 	}
 	fmsg.Exit(r)
+	panic("unreachable")
 }

nixos.nix

@@ -7,290 +7,212 @@
 
 let
   inherit (lib)
-    types
-    mkOption
-    mkEnableOption
     mkIf
+    mkDefault
     mapAttrs
     mapAttrsToList
+    mergeAttrsList
+    imap1
+    foldr
     foldlAttrs
     optional
+    optionals
     ;
 
   cfg = config.environment.fortify;
 in
 
 {
-  options = {
+  imports = [ ./options.nix ];
-    environment.fortify = {
-      enable = mkEnableOption "fortify";
-
-      target = mkOption {
-        default = { };
-        type =
-          let
-            inherit (types)
-              str
-              enum
-              bool
-              package
-              anything
-              submodule
-              listOf
-              attrsOf
-              nullOr
-              ;
-          in
-          attrsOf (submodule {
-            options = {
-              packages = mkOption {
-                type = listOf package;
-                default = [ ];
-                description = ''
-                  List of extra packages to install via home-manager.
-                '';
-              };
-
-              launchers = mkOption {
-                type = attrsOf (submodule {
-                  options = {
-                    command = mkOption {
-                      type = nullOr str;
-                      default = null;
-                      description = ''
-                        Command to run as the target user.
-                        Setting this to null will default command to wrapper name.
-                      '';
-                    };
-
-                    dbus = {
-                      config = mkOption {
-                        type = nullOr anything;
-                        default = null;
-                        description = ''
-                          D-Bus custom configuration.
-                          Setting this to null will enable built-in defaults.
-                        '';
-                      };
-
-                      configSystem = mkOption {
-                        type = nullOr anything;
-                        default = null;
-                        description = ''
-                          D-Bus system bus custom configuration.
-                          Setting this to null will disable the system bus proxy.
-                        '';
-                      };
-
-                      id = mkOption {
-                        type = nullOr str;
-                        default = null;
-                        description = ''
-                          D-Bus application id.
-                          Setting this to null will disable own path in defaults.
-                          Has no effect if custom configuration is set.
-                        '';
-                      };
-
-                      mpris = mkOption {
-                        type = bool;
-                        default = false;
-                        description = ''
-                          Whether to enable MPRIS in D-Bus defaults.
-                        '';
-                      };
-                    };
-
-                    capability = {
-                      wayland = mkOption {
-                        type = bool;
-                        default = true;
-                        description = ''
-                          Whether to share the Wayland socket.
-                        '';
-                      };
-
-                      x11 = mkOption {
-                        type = bool;
-                        default = false;
-                        description = ''
-                          Whether to share the X11 socket and allow connection.
-                        '';
-                      };
-
-                      dbus = mkOption {
-                        type = bool;
-                        default = true;
-                        description = ''
-                          Whether to proxy D-Bus.
-                        '';
-                      };
-
-                      pulse = mkOption {
-                        type = bool;
-                        default = true;
-                        description = ''
-                          Whether to share the PulseAudio socket and cookie.
-                        '';
-                      };
-                    };
-
-                    share = mkOption {
-                      type = nullOr package;
-                      default = null;
-                      description = ''
-                        Package containing share files.
-                        Setting this to null will default package name to wrapper name.
-                      '';
-                    };
-
-                    method = mkOption {
-                      type = enum [
-                        "simple"
-                        "sudo"
-                        "systemd"
-                      ];
-                      default = "systemd";
-                      description = ''
-                        Launch method for the sandboxed program.
-                      '';
-                    };
-                  };
-                });
-                default = { };
-              };
-
-              persistence = mkOption {
-                type = submodule {
-                  options = {
-                    directories = mkOption {
-                      type = listOf anything;
-                      default = [ ];
-                    };
-
-                    files = mkOption {
-                      type = listOf anything;
-                      default = [ ];
-                    };
-                  };
-                };
-                description = ''
-                  Per-user state passed to github:nix-community/impermanence.
-                '';
-              };
-
-              extraConfig = mkOption {
-                type = anything;
-                default = { };
-                description = "Extra home-manager configuration.";
-              };
-            };
-          });
-      };
-
-      package = mkOption {
-        type = types.package;
-        default = pkgs.callPackage ./package.nix { };
-        description = "Package providing fortify.";
-      };
-
-      user = mkOption {
-        type = types.str;
-        description = "Privileged user account.";
-      };
-
-      stateDir = mkOption {
-        type = types.str;
-        description = ''
-          The path to persistent storage where per-user state should be stored.
-        '';
-      };
-    };
-  };
 
   config = mkIf cfg.enable {
-    environment.persistence.${cfg.stateDir}.users = mapAttrs (_: target: target.persistence) cfg.target;
+    security.wrappers.fsu = {
-
+      source = "${cfg.package}/libexec/fsu";
-    home-manager.users =
+      setuid = true;
-      mapAttrs (_: target: target.extraConfig // { home.packages = target.packages; }) cfg.target
+      owner = "root";
-      // {
+      setgid = true;
-        ${cfg.user}.home.packages =
+      group = "root";
-          let
-            wrap =
-              user: launchers:
-              mapAttrsToList (
-                name: launcher:
-                with launcher.capability;
-                let
-                  command = if launcher.command == null then name else launcher.command;
-                  dbusConfig =
-                    if launcher.dbus.config != null then
-                      pkgs.writeText "${name}-dbus.json" (builtins.toJSON launcher.dbus.config)
-                    else
-                      null;
-                  dbusSystem =
-                    if launcher.dbus.configSystem != null then
-                      pkgs.writeText "${name}-dbus-system.json" (builtins.toJSON launcher.dbus.configSystem)
-                    else
-                      null;
-                  capArgs =
-                    (if wayland then " --wayland" else "")
-                    + (if x11 then " -X" else "")
-                    + (if dbus then " --dbus" else "")
-                    + (if pulse then " --pulse" else "")
-                    + (if launcher.dbus.mpris then " --mpris" else "")
-                    + (if launcher.dbus.id != null then " --dbus-id ${launcher.dbus.id}" else "")
-                    + (if dbusConfig != null then " --dbus-config ${dbusConfig}" else "")
-                    + (if dbusSystem != null then " --dbus-system ${dbusSystem}" else "");
-                in
-                pkgs.writeShellScriptBin name (
-                  if launcher.method == "simple" then
-                    ''
-                      exec sudo -u ${user} -i ${command} $@
-                    ''
-                  else
-                    ''
-                      exec fortify${capArgs} --method ${launcher.method} -u ${user} $SHELL -c "exec ${command} $@"
-                    ''
-                )
-              ) launchers;
-          in
-          foldlAttrs (
-            acc: user: target:
-            acc
-            ++ (foldlAttrs (
-              shares: name: launcher:
-              let
-                pkg = if launcher.share != null then launcher.share else pkgs.${name};
-                link = source: "[ -d '${source}' ] && ln -sv '${source}' $out/share || true";
-              in
-              shares
-              ++
-                optional (launcher.method != "simple" && (launcher.capability.wayland || launcher.capability.x11))
-                  (
-                    pkgs.runCommand "${name}-share" { } ''
-                      mkdir -p $out/share
-                      ${link "${pkg}/share/applications"}
-                      ${link "${pkg}/share/icons"}
-                      ${link "${pkg}/share/man"}
-                    ''
-                  )
-            ) (wrap user target.launchers) target.launchers)
-          ) [ cfg.package ] cfg.target;
     };
 
-    security.polkit.extraConfig =
+    environment.etc = {
-      let
+      fsurc = {
-        allowList = builtins.toJSON (mapAttrsToList (name: _: name) cfg.target);
+        mode = "0400";
-      in
+        text = foldlAttrs (
-      ''
+          acc: username: fid:
-        polkit.addRule(function(action, subject) {
+          "${toString config.users.users.${username}.uid} ${toString fid}\n" + acc
-          if (action.id == "org.freedesktop.machine1.host-shell" &&
+        ) "" cfg.users;
-            ${allowList}.indexOf(action.lookup("user")) > -1 &&
+      };
-            subject.user == "${cfg.user}") {
+
-                return polkit.Result.YES;
+      userdb.source = pkgs.runCommand "fortify-userdb" { } ''
+        ${cfg.package}/libexec/fuserdb -o $out ${
+          foldlAttrs (
+            acc: username: fid:
+            acc + " ${username}:${toString fid}"
+          ) "-s /run/current-system/sw/bin/nologin -d ${cfg.stateDir}" cfg.users
         }
-        });
       '';
     };
+
+    services.userdbd.enable = mkDefault true;
+
+    home-manager =
+      let
+        privPackages = mapAttrs (username: fid: {
+          home.packages =
+            let
+              # aid 0 is reserved
+              wrappers = imap1 (
+                aid: app:
+                let
+                  extendDBusDefault = id: ext: {
+                    filter = true;
+
+                    talk = [ "org.freedesktop.Notifications" ] ++ ext.talk;
+                    own =
+                      (optionals (app.id != null) [
+                        "${id}.*"
+                        "org.mpris.MediaPlayer2.${id}.*"
+                      ])
+                      ++ ext.own;
+
+                    inherit (ext) call broadcast;
+                  };
+                  dbusConfig =
+                    let
+                      default = {
+                        talk = [ ];
+                        own = [ ];
+                        call = { };
+                        broadcast = { };
+                      };
+                    in
+                    {
+                      session_bus =
+                        if app.dbus.session != null then
+                          (app.dbus.session (extendDBusDefault app.id))
+                        else
+                          (extendDBusDefault app.id default);
+                      system_bus = app.dbus.system;
+                    };
+                  command = if app.command == null then app.name else app.command;
+                  script = if app.script == null then ("exec " + command + " $@") else app.script;
+                  enablements =
+                    with app.capability;
+                    (if wayland then 1 else 0)
+                    + (if x11 then 2 else 0)
+                    + (if dbus then 4 else 0)
+                    + (if pulse then 8 else 0);
+                  conf = {
+                    inherit (app) id;
+                    command = [
+                      (pkgs.writeScript "${app.name}-start" ''
+                        #!${pkgs.zsh}${pkgs.zsh.shellPath}
+                        ${script}
+                      '')
+                    ];
+                    confinement = {
+                      app_id = aid;
+                      inherit (app) groups;
+                      username = "u${toString fid}_a${toString aid}";
+                      home = "${cfg.stateDir}/${toString fid}/${toString aid}";
+                      sandbox = {
+                        inherit (app)
+                          userns
+                          net
+                          dev
+                          env
+                          ;
+                        map_real_uid = app.mapRealUid;
+                        filesystem =
+                          [
+                            { src = "/bin"; }
+                            { src = "/usr/bin"; }
+                            { src = "/nix/store"; }
+                            { src = "/run/current-system"; }
+                            {
+                              src = "/sys/block";
+                              require = false;
+                            }
+                            {
+                              src = "/sys/bus";
+                              require = false;
+                            }
+                            {
+                              src = "/sys/class";
+                              require = false;
+                            }
+                            {
+                              src = "/sys/dev";
+                              require = false;
+                            }
+                            {
+                              src = "/sys/devices";
+                              require = false;
+                            }
+                          ]
+                          ++ optionals app.nix [
+                            { src = "/nix/var"; }
+                            { src = "/var/db/nix-channels"; }
+                          ]
+                          ++ optionals (if app.gpu != null then app.gpu else app.capability.wayland || app.capability.x11) [
+                            { src = "/run/opengl-driver"; }
+                            {
+                              src = "/dev/dri";
+                              dev = true;
+                            }
+                          ]
+                          ++ app.extraPaths;
+                        auto_etc = true;
+                        override = [ "/var/run/nscd" ];
+                      };
+                      inherit enablements;
+                      inherit (dbusConfig) session_bus system_bus;
+                    };
+                  };
+                in
+                pkgs.writeShellScriptBin app.name ''
+                  exec fortify app ${pkgs.writeText "fortify-${app.name}.json" (builtins.toJSON conf)} $@
+                ''
+              ) cfg.apps;
+            in
+            foldr (
+              app: acc:
+              let
+                pkg = if app.share != null then app.share else pkgs.${app.name};
+                copy = source: "[ -d '${source}' ] && cp -Lrv '${source}' $out/share || true";
+              in
+              optional (app.capability.wayland || app.capability.x11) (
+                pkgs.runCommand "${app.name}-share" { } ''
+                  mkdir -p $out/share
+                  ${copy "${pkg}/share/applications"}
+                  ${copy "${pkg}/share/pixmaps"}
+                  ${copy "${pkg}/share/icons"}
+                  ${copy "${pkg}/share/man"}
+
+                  substituteInPlace $out/share/applications/* \
+                    --replace-warn '${pkg}/bin/' "" \
+                    --replace-warn '${pkg}/libexec/' ""
+                ''
+              )
+              ++ acc
+            ) (wrappers ++ [ cfg.package ]) cfg.apps;
+        }) cfg.users;
+      in
+      {
+        useUserPackages = false; # prevent users.users entries from being added
+
+        users = foldlAttrs (
+          acc: _: fid:
+          mergeAttrsList (
+            # aid 0 is reserved
+            imap1 (aid: app: {
+              "u${toString fid}_a${toString aid}" = app.extraConfig // {
+                home.packages = app.packages;
+              };
+            }) cfg.apps
+          )
+          // acc
+        ) privPackages cfg.users;
+      };
+  };
 }

options.md

@@ -0,0 +1,531 @@
+## environment\.fortify\.enable
+
+
+
+Whether to enable fortify\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` false `
+
+
+
+*Example:*
+` true `
+
+
+
+
+## environment\.fortify\.package
+
+
+
+The fortify package to use\.
+
+
+
+*Type:*
+package
+
+
+
+*Default:*
+` <derivation fortify-0.1.0> `
+
+
+
+
+## environment\.fortify\.apps
+
+Declarative fortify apps\.
+
+
+
+*Type:*
+list of (submodule)
+
+
+
+*Default:*
+` [ ] `
+
+
+
+
+## environment\.fortify\.apps\.\*\.packages
+
+
+
+List of extra packages to install via home-manager\.
+
+
+
+*Type:*
+list of package
+
+
+
+*Default:*
+` [ ] `
+
+
+
+
+## environment\.fortify\.apps\.\*\.capability\.dbus
+
+
+
+Whether to proxy D-Bus\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` true `
+
+
+
+
+## environment\.fortify\.apps\.\*\.capability\.pulse
+
+
+
+Whether to share the PulseAudio socket and cookie\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` true `
+
+
+
+
+## environment\.fortify\.apps\.\*\.capability\.wayland
+
+
+
+Whether to share the Wayland socket\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` true `
+
+
+
+
+## environment\.fortify\.apps\.\*\.capability\.x11
+
+
+
+Whether to share the X11 socket and allow connection\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` false `
+
+
+
+
+## environment\.fortify\.apps\.\*\.command
+
+
+
+Command to run as the target user\.
+Setting this to null will default command to launcher name\.
+Has no effect when script is set\.
+
+
+
+*Type:*
+null or string
+
+
+
+*Default:*
+` null `
+
+
+
+
+## environment\.fortify\.apps\.\*\.dbus\.session
+
+
+
+D-Bus session bus custom configuration\.
+Setting this to null will enable built-in defaults\.
+
+
+
+*Type:*
+null or (function that evaluates to a(n) anything)
+
+
+
+*Default:*
+` null `
+
+
+
+
+## environment\.fortify\.apps\.\*\.dbus\.system
+
+
+
+D-Bus system bus custom configuration\.
+Setting this to null will disable the system bus proxy\.
+
+
+
+*Type:*
+null or anything
+
+
+
+*Default:*
+` null `
+
+
+
+
+## environment\.fortify\.apps\.\*\.dev
+
+
+
+Whether to enable access to all devices within the sandbox\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` false `
+
+
+
+*Example:*
+` true `
+
+
+
+
+## environment\.fortify\.apps\.\*\.env
+
+
+
+Environment variables to set for the initial process in the sandbox\.
+
+
+
+*Type:*
+null or (attribute set of string)
+
+
+
+*Default:*
+` null `
+
+
+
+
+## environment\.fortify\.apps\.\*\.extraConfig
+
+
+
+Extra home-manager configuration\.
+
+
+
+*Type:*
+anything
+
+
+
+*Default:*
+` { } `
+
+
+
+
+## environment\.fortify\.apps\.\*\.extraPaths
+
+
+
+Extra paths to make available to the sandbox\.
+
+
+
+*Type:*
+list of anything
+
+
+
+*Default:*
+` [ ] `
+
+
+
+
+## environment\.fortify\.apps\.\*\.gpu
+
+
+
+Target process GPU and driver access\.
+Setting this to null will enable GPU whenever X or Wayland is enabled\.
+
+
+
+*Type:*
+null or boolean
+
+
+
+*Default:*
+` null `
+
+
+
+
+## environment\.fortify\.apps\.\*\.groups
+
+
+
+List of groups to inherit from the privileged user\.
+
+
+
+*Type:*
+list of string
+
+
+
+*Default:*
+` [ ] `
+
+
+
+
+## environment\.fortify\.apps\.\*\.id
+
+
+
+Freedesktop application ID\.
+
+
+
+*Type:*
+null or string
+
+
+
+*Default:*
+` null `
+
+
+
+
+## environment\.fortify\.apps\.\*\.mapRealUid
+
+
+
+Whether to enable mapping to fortify’s real UID within the sandbox\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` false `
+
+
+
+*Example:*
+` true `
+
+
+
+
+## environment\.fortify\.apps\.\*\.name
+
+
+
+Name of the app’s launcher script\.
+
+
+
+*Type:*
+string
+
+
+
+
+## environment\.fortify\.apps\.\*\.net
+
+
+
+Whether to enable network access within the sandbox\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` true `
+
+
+
+*Example:*
+` true `
+
+
+
+
+## environment\.fortify\.apps\.\*\.nix
+
+
+
+Whether to enable nix daemon access within the sandbox\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` false `
+
+
+
+*Example:*
+` true `
+
+
+
+
+## environment\.fortify\.apps\.\*\.script
+
+
+
+Application launch script\.
+
+
+
+*Type:*
+null or string
+
+
+
+*Default:*
+` null `
+
+
+
+
+## environment\.fortify\.apps\.\*\.share
+
+
+
+Package containing share files\.
+Setting this to null will default package name to wrapper name\.
+
+
+
+*Type:*
+null or package
+
+
+
+*Default:*
+` null `
+
+
+
+
+## environment\.fortify\.apps\.\*\.userns
+
+
+
+Whether to enable userns within the sandbox\.
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` false `
+
+
+
+*Example:*
+` true `
+
+
+
+
+## environment\.fortify\.stateDir
+
+
+
+The state directory where app home directories are stored\.
+
+
+
+*Type:*
+string
+
+
+
+
+## environment\.fortify\.users
+
+
+
+Users allowed to spawn fortify apps and their corresponding fortify fid\.
+
+
+
+*Type:*
+attribute set of integer between 0 and 99 (both inclusive)
+
+
+

options.nix

@@ -0,0 +1,214 @@
+{ lib, pkgs, ... }:
+
+let
+  inherit (lib) types mkOption mkEnableOption;
+in
+
+{
+  options = {
+    environment.fortify = {
+      enable = mkEnableOption "fortify";
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.callPackage ./package.nix { };
+        description = "The fortify package to use.";
+      };
+
+      users = mkOption {
+        type =
+          let
+            inherit (types) attrsOf ints;
+          in
+          attrsOf (ints.between 0 99);
+        description = ''
+          Users allowed to spawn fortify apps and their corresponding fortify fid.
+        '';
+      };
+
+      apps = mkOption {
+        type =
+          let
+            inherit (types)
+              str
+              enum
+              bool
+              package
+              anything
+              submodule
+              listOf
+              attrsOf
+              nullOr
+              functionTo
+              ;
+          in
+          listOf (submodule {
+            options = {
+              name = mkOption {
+                type = str;
+                description = ''
+                  Name of the app's launcher script.
+                '';
+              };
+
+              id = mkOption {
+                type = nullOr str;
+                default = null;
+                description = ''
+                  Freedesktop application ID.
+                '';
+              };
+
+              packages = mkOption {
+                type = listOf package;
+                default = [ ];
+                description = ''
+                  List of extra packages to install via home-manager.
+                '';
+              };
+
+              extraConfig = mkOption {
+                type = anything;
+                default = { };
+                description = ''
+                  Extra home-manager configuration.
+                '';
+              };
+
+              script = mkOption {
+                type = nullOr str;
+                default = null;
+                description = ''
+                  Application launch script.
+                '';
+              };
+
+              command = mkOption {
+                type = nullOr str;
+                default = null;
+                description = ''
+                  Command to run as the target user.
+                  Setting this to null will default command to launcher name.
+                  Has no effect when script is set.
+                '';
+              };
+
+              groups = mkOption {
+                type = listOf str;
+                default = [ ];
+                description = ''
+                  List of groups to inherit from the privileged user.
+                '';
+              };
+
+              dbus = {
+                session = mkOption {
+                  type = nullOr (functionTo anything);
+                  default = null;
+                  description = ''
+                    D-Bus session bus custom configuration.
+                    Setting this to null will enable built-in defaults.
+                  '';
+                };
+
+                system = mkOption {
+                  type = nullOr anything;
+                  default = null;
+                  description = ''
+                    D-Bus system bus custom configuration.
+                    Setting this to null will disable the system bus proxy.
+                  '';
+                };
+              };
+
+              env = mkOption {
+                type = nullOr (attrsOf str);
+                default = null;
+                description = ''
+                  Environment variables to set for the initial process in the sandbox.
+                '';
+              };
+
+              nix = mkEnableOption "nix daemon access within the sandbox";
+              userns = mkEnableOption "userns within the sandbox";
+              mapRealUid = mkEnableOption "mapping to fortify's real UID within the sandbox";
+              dev = mkEnableOption "access to all devices within the sandbox";
+
+              net = mkEnableOption "network access within the sandbox" // {
+                default = true;
+              };
+
+              gpu = mkOption {
+                type = nullOr bool;
+                default = null;
+                description = ''
+                  Target process GPU and driver access.
+                  Setting this to null will enable GPU whenever X or Wayland is enabled.
+                '';
+              };
+
+              extraPaths = mkOption {
+                type = listOf anything;
+                default = [ ];
+                description = ''
+                  Extra paths to make available to the sandbox.
+                '';
+              };
+
+              capability = {
+                wayland = mkOption {
+                  type = bool;
+                  default = true;
+                  description = ''
+                    Whether to share the Wayland socket.
+                  '';
+                };
+
+                x11 = mkOption {
+                  type = bool;
+                  default = false;
+                  description = ''
+                    Whether to share the X11 socket and allow connection.
+                  '';
+                };
+
+                dbus = mkOption {
+                  type = bool;
+                  default = true;
+                  description = ''
+                    Whether to proxy D-Bus.
+                  '';
+                };
+
+                pulse = mkOption {
+                  type = bool;
+                  default = true;
+                  description = ''
+                    Whether to share the PulseAudio socket and cookie.
+                  '';
+                };
+              };
+
+              share = mkOption {
+                type = nullOr package;
+                default = null;
+                description = ''
+                  Package containing share files.
+                  Setting this to null will default package name to wrapper name.
+                '';
+              };
+            };
+          });
+        default = [ ];
+        description = "Declarative fortify apps.";
+      };
+
+      stateDir = mkOption {
+        type = types.str;
+        description = ''
+          The state directory where app home directories are stored.
+        '';
+      };
+    };
+  };
+}

package.nix

@@ -10,19 +10,34 @@
 
 buildGoModule rec {
   pname = "fortify";
-  version = "0.0.10";
+  version = "0.2.1";
 
   src = ./.;
   vendorHash = null;
 
-  ldflags = [
+  ldflags =
+    lib.attrsets.foldlAttrs
+      (
+        ldflags: name: value:
+        ldflags
+        ++ [
+          "-X"
+          "git.ophivana.moe/security/fortify/internal.${name}=${value}"
+        ]
+      )
+      [
         "-s"
         "-w"
         "-X"
-    "main.Version=v${version}"
+        "main.Fmain=${placeholder "out"}/libexec/fortify"
         "-X"
-    "main.FortifyPath=${placeholder "out"}/bin/.fortify-wrapped"
+        "main.Fshim=${placeholder "out"}/libexec/fshim"
-  ];
+      ]
+      {
+        Version = "v${version}";
+        Fsu = "/run/wrappers/bin/fsu";
+        Finit = "${placeholder "out"}/libexec/finit";
+      };
 
   buildInputs = [
     acl
@@ -32,13 +47,15 @@ buildGoModule rec {
   nativeBuildInputs = [ makeBinaryWrapper ];
 
   postInstall = ''
-    wrapProgram $out/bin/${pname} --prefix PATH : ${
+    mkdir "$out/libexec"
+    mv "$out"/bin/* "$out/libexec/"
+
+    makeBinaryWrapper "$out/libexec/fortify" "$out/bin/fortify" \
+      --inherit-argv0 --prefix PATH : ${
         lib.makeBinPath [
           bubblewrap
           xdg-dbus-proxy
         ]
       }
-
-    mv $out/bin/fsu $out/bin/.fsu
   '';
 }

state.go

@@ -1,35 +0,0 @@
-package main
-
-import (
-	"flag"
-	"fmt"
-	"text/tabwriter"
-
-	"git.ophivana.moe/security/fortify/internal/fmsg"
-	"git.ophivana.moe/security/fortify/internal/state"
-)
-
-var (
-	stateActionEarly bool
-)
-
-func init() {
-	flag.BoolVar(&stateActionEarly, "state", false, "print state information of active launchers")
-}
-
-// tryState is called after app initialisation
-func tryState() {
-	if stateActionEarly {
-		var w *tabwriter.Writer
-		state.MustPrintLauncherStateSimpleGlobal(&w, os.Paths().RunDirPath)
-		if w != nil {
-			if err := w.Flush(); err != nil {
-				fmsg.Println("cannot format output:", err)
-			}
-		} else {
-			fmt.Println("No information available")
-		}
-
-		fmsg.Exit(0)
-	}
-}

version.go

@@ -1,23 +0,0 @@
-package main
-
-import (
-	"flag"
-	"fmt"
-)
-
-var (
-	Version = "impure"
-
-	printVersion bool
-)
-
-func init() {
-	flag.BoolVar(&printVersion, "V", false, "Print version")
-}
-
-func tryVersion() {
-	if printVersion {
-		fmt.Println(Version)
-		os.Exit(0)
-	}
-}

xcb/export.go

@@ -1,3 +1,4 @@
+// Package xcb implements X11 ChangeHosts via libxcb.
 package xcb
 
 //#include <stdlib.h>