internal/outcome: rename from app

This is less ambiguous, and more accurately describes the purpose of the package.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 477 insertions, 0 deletions

diff --git a/internal/outcome/spcontainer_test.go b/internal/outcome/spcontainer_test.go
new file mode 100644
index 00000000..3b003054
--- /dev/null
+++ b/internal/outcome/spcontainer_test.go
@@ -0,0 +1,477 @@
+package outcome
+
+import (
+	"errors"
+	"os"
+	"reflect"
+	"syscall"
+	"testing"
+
+	"hakurei.app/container"
+	"hakurei.app/container/check"
+	"hakurei.app/container/comp"
+	"hakurei.app/container/fhs"
+	"hakurei.app/container/seccomp"
+	"hakurei.app/container/stub"
+	"hakurei.app/hst"
+	"hakurei.app/system"
+	"hakurei.app/system/acl"
+	"hakurei.app/system/dbus"
+)
+
+func TestSpParamsOp(t *testing.T) {
+	t.Parallel()
+	config := hst.Template()
+
+	checkOpBehaviour(t, []opBehaviourTestCase{
+		{"invalid program path", func(isShim, _ bool) outcomeOp {
+			if !isShim {
+				return new(spParamsOp)
+			}
+			return &spParamsOp{Term: "xterm", TermSet: true}
+		}, func() *hst.Config {
+			c := hst.Template()
+			c.Container.Path = nil
+			return c
+		}, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{"TERM"}, "xterm", nil),
+		}, newI().
+			Ensure(m(container.Nonexistent+"/tmp/hakurei.0"), 0711), nil, nil, nil, []stub.Call{
+			// this op configures the container state and does not make calls during toContainer
+		}, nil, nil, &hst.AppError{
+			Step: "finalise",
+			Err:  os.ErrInvalid,
+			Msg:  "invalid program path",
+		}},
+
+		{"success defaultargs secure", func(isShim, _ bool) outcomeOp {
+			if !isShim {
+				return new(spParamsOp)
+			}
+			return &spParamsOp{Term: "xterm", TermSet: true}
+		}, func() *hst.Config {
+			c := hst.Template()
+			c.Container.Args = nil
+			c.Container.Flags = hst.FHostNet | hst.FHostAbstract | hst.FMapRealUID
+			return c
+		}, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{"TERM"}, "xterm", nil),
+		}, newI().
+			Ensure(m(container.Nonexistent+"/tmp/hakurei.0"), 0711), nil, nil, nil, []stub.Call{
+			// this op configures the container state and does not make calls during toContainer
+		}, &container.Params{
+			Hostname:       config.Container.Hostname,
+			HostNet:        true,
+			HostAbstract:   true,
+			Path:           config.Container.Path,
+			Args:           []string{config.Container.Path.String()},
+			SeccompPresets: comp.PresetExt | comp.PresetDenyDevel | comp.PresetDenyNS | comp.PresetDenyTTY,
+			Uid:            1000,
+			Gid:            100,
+			Ops: new(container.Ops).
+				Root(m("/var/lib/hakurei/base/org.debian"), comp.BindWritable).
+				Proc(fhs.AbsProc).Tmpfs(hst.AbsPrivateTmp, 1<<12, 0755).
+				DevWritable(fhs.AbsDev, true).
+				Tmpfs(fhs.AbsDev.Append("shm"), 0, 01777),
+		}, paramsWantEnv(config, map[string]string{
+			"TERM": "xterm",
+		}, func(t *testing.T, state *outcomeStateParams) {
+			if state.as.AutoEtcPrefix != wantAutoEtcPrefix {
+				t.Errorf("toContainer: as.AutoEtcPrefix = %q, want %q", state.as.AutoEtcPrefix, wantAutoEtcPrefix)
+			}
+
+			wantFilesystems := config.Container.Filesystem[1:]
+			if !reflect.DeepEqual(state.filesystem, wantFilesystems) {
+				t.Errorf("toContainer: filesystem = %#v, want %#v", state.filesystem, wantFilesystems)
+			}
+		}), nil},
+
+		{"success", func(isShim, _ bool) outcomeOp {
+			if !isShim {
+				return new(spParamsOp)
+			}
+			return &spParamsOp{Term: "xterm", TermSet: true}
+		}, hst.Template, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{"TERM"}, "xterm", nil),
+		}, newI().
+			Ensure(m(container.Nonexistent+"/tmp/hakurei.0"), 0711), nil, nil, nil, []stub.Call{
+			// this op configures the container state and does not make calls during toContainer
+		}, &container.Params{
+			Hostname:      config.Container.Hostname,
+			RetainSession: true,
+			HostNet:       true,
+			HostAbstract:  true,
+			Path:          config.Container.Path,
+			Args:          config.Container.Args,
+			SeccompFlags:  seccomp.AllowMultiarch,
+			Uid:           1000,
+			Gid:           100,
+			Ops: new(container.Ops).
+				Root(m("/var/lib/hakurei/base/org.debian"), comp.BindWritable).
+				Proc(fhs.AbsProc).Tmpfs(hst.AbsPrivateTmp, 1<<12, 0755).
+				Bind(fhs.AbsDev, fhs.AbsDev, comp.BindWritable|comp.BindDevice).
+				Tmpfs(fhs.AbsDev.Append("shm"), 0, 01777),
+		}, paramsWantEnv(config, map[string]string{
+			"TERM": "xterm",
+		}, func(t *testing.T, state *outcomeStateParams) {
+			if state.as.AutoEtcPrefix != wantAutoEtcPrefix {
+				t.Errorf("toContainer: as.AutoEtcPrefix = %q, want %q", state.as.AutoEtcPrefix, wantAutoEtcPrefix)
+			}
+
+			wantFilesystems := config.Container.Filesystem[1:]
+			if !reflect.DeepEqual(state.filesystem, wantFilesystems) {
+				t.Errorf("toContainer: filesystem = %#v, want %#v", state.filesystem, wantFilesystems)
+			}
+		}), nil},
+	})
+}
+
+func TestSpFilesystemOp(t *testing.T) {
+	const nePrefix = container.Nonexistent + "/eval"
+	var stubDebianRoot = stubDir("bin", "dev", "etc", "home", "lib64", "lost+found",
+		"mnt", "nix", "proc", "root", "run", "srv", "sys", "tmp", "usr", "var")
+	config := hst.Template()
+
+	newConfigSmall := func() *hst.Config {
+		c := hst.Template()
+		c.Container.Filesystem = []hst.FilesystemConfigJSON{
+			{FilesystemConfig: &hst.FSBind{Target: fhs.AbsEtc, Source: fhs.AbsEtc, Special: true}},
+			{FilesystemConfig: &hst.FSOverlay{Target: m("/nix/store"), Lower: []*check.Absolute{
+				fhs.AbsVarLib.Append("hakurei/base/org.nixos/.ro-store"),
+				fhs.AbsVarLib.Append("hakurei/base/org.nixos/org.chromium.Chromium"),
+			}}},
+			{FilesystemConfig: &hst.FSEphemeral{Target: hst.AbsPrivateTmp}},
+		}
+		c.Container.Flags &= ^hst.FDevice
+		return c
+	}
+	configSmall := newConfigSmall()
+
+	needsApplyState := func(next pStateContainerFunc) pStateContainerFunc {
+		return func(state *outcomeStateParams) {
+			state.as = hst.ApplyState{AutoEtcPrefix: wantAutoEtcPrefix, Ops: opsAdapter{state.params.Ops}}
+
+			if next != nil {
+				next(state)
+			}
+		}
+	}
+
+	checkOpBehaviour(t, []opBehaviourTestCase{
+		{"readdir", func(bool, bool) outcomeOp {
+			return new(spFilesystemOp)
+		}, hst.Template, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, nePrefix+"/xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, nePrefix+"/tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "", &os.PathError{Op: "lstat", Path: "/var/run/nscd", Err: os.ErrNotExist}),
+			call("verbosef", stub.ExpectArgs{"path %q does not yet exist", []any{"/var/run/nscd"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/dbus"}, nePrefix+"/run/dbus", nil),
+			call("readdir", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian"}, []os.DirEntry{}, stub.UniqueError(2)),
+		}, nil, nil, &hst.AppError{
+			Step: "access autoroot source",
+			Err:  stub.UniqueError(2),
+		}, nil, nil, nil, nil, nil},
+
+		{"invalid dbus address", func(bool, bool) outcomeOp { return new(spFilesystemOp) }, func() *hst.Config {
+			c := newConfigSmall()
+			c.Container.Filesystem = append(c.Container.Filesystem, hst.FilesystemConfigJSON{FilesystemConfig: invalidFSHost(false)})
+			return c
+		}, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid", nil),
+		}, nil, nil, &hst.AppError{
+			Step: "parse dbus address",
+			Err: &dbus.BadAddressError{
+				Type:     dbus.ErrNoColon,
+				EntryVal: []byte("invalid"),
+				PairPos:  -1,
+			},
+		}, nil, nil, nil, nil, nil},
+
+		{"invalid fs early", func(bool, bool) outcomeOp { return new(spFilesystemOp) }, func() *hst.Config {
+			c := newConfigSmall()
+			c.Container.Filesystem = append(c.Container.Filesystem, hst.FilesystemConfigJSON{FilesystemConfig: invalidFSHost(false)})
+			return c
+		}, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid:meow=0;unix:path=/system_bus_socket;unix:path=system_bus_socket", nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is in an unusual location", []any{"/system_bus_socket"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is not absolute", []any{"system_bus_socket"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, nePrefix+"/xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, nePrefix+"/tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "", &os.PathError{Op: "lstat", Path: "/var/run/nscd", Err: os.ErrNotExist}),
+			call("verbosef", stub.ExpectArgs{"path %q does not yet exist", []any{"/var/run/nscd"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/"}, nePrefix+"/etc/dbus", nil), // to match hidePaths
+		}, nil, nil, &hst.AppError{
+			Step: "finalise",
+			Err:  os.ErrInvalid,
+			Msg:  "invalid filesystem at index 3",
+		}, nil, nil, nil, nil, nil},
+
+		{"evalSymlinks early", func(bool, bool) outcomeOp { return new(spFilesystemOp) }, newConfigSmall, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid:meow=0;unix:path=/system_bus_socket;unix:path=system_bus_socket", nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is in an unusual location", []any{"/system_bus_socket"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is not absolute", []any{"system_bus_socket"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, "", stub.UniqueError(0)),
+		}, nil, nil, &hst.AppError{
+			Step: "evaluate path hiding target",
+			Err:  stub.UniqueError(0),
+		}, nil, nil, nil, nil, nil},
+
+		{"host nil abs", func(bool, bool) outcomeOp { return new(spFilesystemOp) }, func() *hst.Config {
+			c := newConfigSmall()
+			c.Container.Filesystem = append(c.Container.Filesystem, hst.FilesystemConfigJSON{FilesystemConfig: invalidFSHost(true)})
+			return c
+		}, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid:meow=0;unix:path=/system_bus_socket;unix:path=system_bus_socket", nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is in an unusual location", []any{"/system_bus_socket"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is not absolute", []any{"system_bus_socket"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, nePrefix+"/xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, nePrefix+"/tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "", &os.PathError{Op: "lstat", Path: "/var/run/nscd", Err: os.ErrNotExist}),
+			call("verbosef", stub.ExpectArgs{"path %q does not yet exist", []any{"/var/run/nscd"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/"}, nePrefix+"/etc/dbus", nil), // to match hidePaths
+			call("evalSymlinks", stub.ExpectArgs{"/etc/"}, nePrefix+"/etc", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/.ro-store"}, nePrefix+"/var/lib/hakurei/base/org.nixos/.ro-store", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/org.chromium.Chromium"}, "var/lib/hakurei/base/org.nixos/org.chromium.Chromium", nil),
+		}, nil, nil, &hst.AppError{
+			Step: "finalise",
+			Err:  os.ErrInvalid,
+			Msg:  "impossible path hiding state reached",
+		}, nil, nil, nil, nil, nil},
+
+		{"evalSymlinks late", func(bool, bool) outcomeOp { return new(spFilesystemOp) }, newConfigSmall, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid:meow=0;unix:path=/system_bus_socket;unix:path=system_bus_socket", nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is in an unusual location", []any{"/system_bus_socket"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is not absolute", []any{"system_bus_socket"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, nePrefix+"/xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, nePrefix+"/tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "", &os.PathError{Op: "lstat", Path: "/var/run/nscd", Err: os.ErrNotExist}),
+			call("verbosef", stub.ExpectArgs{"path %q does not yet exist", []any{"/var/run/nscd"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/"}, nePrefix+"/etc/dbus", nil), // to match hidePaths
+			call("evalSymlinks", stub.ExpectArgs{"/etc/"}, nePrefix+"/etc", stub.UniqueError(1)),
+		}, nil, nil, &hst.AppError{
+			Step: "evaluate path hiding source",
+			Err:  stub.UniqueError(1),
+		}, nil, nil, nil, nil, nil},
+
+		{"invalid contains", func(bool, bool) outcomeOp { return new(spFilesystemOp) }, newConfigSmall, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid:meow=0;unix:path=/system_bus_socket;unix:path=system_bus_socket", nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is in an unusual location", []any{"/system_bus_socket"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is not absolute", []any{"system_bus_socket"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, nePrefix+"/xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, nePrefix+"/tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "", &os.PathError{Op: "lstat", Path: "/var/run/nscd", Err: os.ErrNotExist}),
+			call("verbosef", stub.ExpectArgs{"path %q does not yet exist", []any{"/var/run/nscd"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/"}, nePrefix+"/etc/dbus", nil), // to match hidePaths
+			call("evalSymlinks", stub.ExpectArgs{"/etc/"}, nePrefix+"/etc", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/.ro-store"}, nePrefix+"/var/lib/hakurei/base/org.nixos/.ro-store", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/org.chromium.Chromium"}, "var/lib/hakurei/base/org.nixos/org.chromium.Chromium", nil),
+			call("verbosef", stub.ExpectArgs{"hiding path %q from %q", []any{"/proc/nonexistent/eval/etc/dbus", "/etc/"}}, nil, nil),
+		}, nil, nil, &hst.AppError{
+			Step: "determine path hiding outcome",
+			Err:  errors.New("Rel: can't make /proc/nonexistent/eval/xdg_runtime_dir relative to var/lib/hakurei/base/org.nixos/org.chromium.Chromium"),
+		}, nil, nil, nil, nil, nil},
+
+		{"invalid hide", func(bool, bool) outcomeOp { return new(spFilesystemOp) }, newConfigSmall, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid:meow=0;unix:path=/system_bus_socket;unix:path=system_bus_socket", nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is in an unusual location", []any{"/system_bus_socket"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is not absolute", []any{"system_bus_socket"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, "xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, "tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "nscd", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/"}, "nonexistent/dbus", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/etc/"}, "nonexistent", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/.ro-store"}, ".ro-store", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/org.chromium.Chromium"}, "org.chromium.Chromium", nil),
+			call("verbosef", stub.ExpectArgs{"hiding path %q from %q", []any{"nonexistent/dbus", "/etc/"}}, nil, nil),
+		}, nil, nil, &hst.AppError{
+			Step: "finalise",
+			Err:  os.ErrInvalid,
+			Msg:  `invalid path hiding candidate "nonexistent/dbus"`,
+		}, nil, nil, nil, nil, nil},
+
+		{"invalid fs", func(isShim, clearUnexported bool) outcomeOp {
+			if !isShim {
+				return new(spFilesystemOp)
+			}
+			return &spFilesystemOp{HidePaths: []*check.Absolute{m("/proc/nonexistent/eval/etc/dbus")}}
+		}, newConfigSmall, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid:meow=0;unix:path=/system_bus_socket;unix:path=system_bus_socket", nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is in an unusual location", []any{"/system_bus_socket"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is not absolute", []any{"system_bus_socket"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, nePrefix+"/xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, nePrefix+"/tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "", &os.PathError{Op: "lstat", Path: "/var/run/nscd", Err: os.ErrNotExist}),
+			call("verbosef", stub.ExpectArgs{"path %q does not yet exist", []any{"/var/run/nscd"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/"}, nePrefix+"/etc/dbus", nil), // to match hidePaths
+			call("evalSymlinks", stub.ExpectArgs{"/etc/"}, nePrefix+"/etc", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/.ro-store"}, nePrefix+"/var/lib/hakurei/base/org.nixos/.ro-store", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/org.chromium.Chromium"}, nePrefix+"/var/lib/hakurei/base/org.nixos/org.chromium.Chromium", nil),
+			call("verbosef", stub.ExpectArgs{"hiding path %q from %q", []any{"/proc/nonexistent/eval/etc/dbus", "/etc/"}}, nil, nil),
+		}, newI().
+			Ensure(m("/var/lib/hakurei/u0"), 0700).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0"),
+				acl.Execute).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0/org.chromium.Chromium"),
+				acl.Read, acl.Write, acl.Execute), nil, nil, insertsOps(needsApplyState(func(state *outcomeStateParams) {
+			state.filesystem = append(configSmall.Container.Filesystem, hst.FilesystemConfigJSON{})
+		})), []stub.Call{
+			// this op configures the container state and does not make calls during toContainer
+		}, nil, nil, &hst.AppError{
+			Step: "finalise",
+			Err:  os.ErrInvalid,
+			Msg:  "invalid filesystem at index 3",
+		}},
+
+		{"success noroot nodev envdbus strangedbus dbusnotabs hide", func(isShim, clearUnexported bool) outcomeOp {
+			if !isShim {
+				return new(spFilesystemOp)
+			}
+			return &spFilesystemOp{HidePaths: []*check.Absolute{m("/proc/nonexistent/eval/etc/dbus")}}
+		}, newConfigSmall, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, "invalid:meow=0;unix:path=/system_bus_socket;unix:path=system_bus_socket", nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is in an unusual location", []any{"/system_bus_socket"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"dbus socket %q is not absolute", []any{"system_bus_socket"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, nePrefix+"/xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, nePrefix+"/tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "", &os.PathError{Op: "lstat", Path: "/var/run/nscd", Err: os.ErrNotExist}),
+			call("verbosef", stub.ExpectArgs{"path %q does not yet exist", []any{"/var/run/nscd"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/"}, nePrefix+"/etc/dbus", nil), // to match hidePaths
+			call("evalSymlinks", stub.ExpectArgs{"/etc/"}, nePrefix+"/etc", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/.ro-store"}, nePrefix+"/var/lib/hakurei/base/org.nixos/.ro-store", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/org.chromium.Chromium"}, nePrefix+"/var/lib/hakurei/base/org.nixos/org.chromium.Chromium", nil),
+			call("verbosef", stub.ExpectArgs{"hiding path %q from %q", []any{"/proc/nonexistent/eval/etc/dbus", "/etc/"}}, nil, nil),
+		}, newI().
+			Ensure(m("/var/lib/hakurei/u0"), 0700).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0"),
+				acl.Execute).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0/org.chromium.Chromium"),
+				acl.Read, acl.Write, acl.Execute), nil, nil, insertsOps(needsApplyState(func(state *outcomeStateParams) {
+			state.filesystem = configSmall.Container.Filesystem
+		})), []stub.Call{
+			// this op configures the container state and does not make calls during toContainer
+		}, &container.Params{
+			Env: []string{
+				"GOOGLE_API_KEY=AIzaSyBHDrl33hwRp4rMQY0ziRbj8K9LPA6vUCY",
+				"GOOGLE_DEFAULT_CLIENT_ID=77185425430.apps.googleusercontent.com",
+				"GOOGLE_DEFAULT_CLIENT_SECRET=OTJgUOQcT7lO7GsGZq2G4IlT",
+			},
+
+			Ops: new(container.Ops).
+				Etc(fhs.AbsEtc, wantAutoEtcPrefix).
+				OverlayReadonly(
+					check.MustAbs("/nix/store"),
+					fhs.AbsVarLib.Append("hakurei/base/org.nixos/.ro-store"),
+					fhs.AbsVarLib.Append("hakurei/base/org.nixos/org.chromium.Chromium")).
+				Readonly(hst.AbsPrivateTmp, 0755).
+				Tmpfs(m("/proc/nonexistent/eval/etc/dbus"), 1<<13, 0755).
+				Remount(fhs.AbsDev, syscall.MS_RDONLY).
+				Remount(fhs.AbsRoot, syscall.MS_RDONLY),
+		}, nil, nil},
+
+		{"success", func(bool, bool) outcomeOp {
+			return new(spFilesystemOp)
+		}, hst.Template, nil, []stub.Call{
+			call("lookupEnv", stub.ExpectArgs{dbus.SystemBusAddress}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/xdg_runtime_dir"}, nePrefix+"/xdg_runtime_dir", nil),
+			call("evalSymlinks", stub.ExpectArgs{container.Nonexistent + "/tmp/hakurei.0"}, nePrefix+"/tmp/hakurei.0", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/nscd"}, "", &os.PathError{Op: "lstat", Path: "/var/run/nscd", Err: os.ErrNotExist}),
+			call("verbosef", stub.ExpectArgs{"path %q does not yet exist", []any{"/var/run/nscd"}}, nil, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/run/dbus"}, nePrefix+"/run/dbus", nil),
+			call("readdir", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian"}, stubDebianRoot, nil),
+			call("evalSymlinks", stub.ExpectArgs{"/etc/"}, nePrefix+"/etc", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/nix/u0/org.chromium.Chromium/rw-store/upper"}, nePrefix+"/var/lib/hakurei/nix/u0/org.chromium.Chromium/rw-store/upper", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/nix/u0/org.chromium.Chromium/rw-store/work"}, nePrefix+"/var/lib/hakurei/nix/u0/org.chromium.Chromium/rw-store/work", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.nixos/ro-store"}, nePrefix+"/var/lib/hakurei/base/org.nixos/ro-store", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/u0/org.chromium.Chromium"}, nePrefix+"/var/lib/hakurei/u0/org.chromium.Chromium", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/dev/dri"}, nePrefix+"/dev/dri", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/bin"}, nePrefix+"/var/lib/hakurei/base/org.debian/bin", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/home"}, nePrefix+"/var/lib/hakurei/base/org.debian/home", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/lib64"}, nePrefix+"/var/lib/hakurei/base/org.debian/lib64", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/lost+found"}, nePrefix+"/var/lib/hakurei/base/org.debian/lost+found", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/nix"}, nePrefix+"/var/lib/hakurei/base/org.debian/nix", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/root"}, nePrefix+"/var/lib/hakurei/base/org.debian/root", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/run"}, nePrefix+"/var/lib/hakurei/base/org.debian/run", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/srv"}, nePrefix+"/var/lib/hakurei/base/org.debian/srv", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/sys"}, nePrefix+"/var/lib/hakurei/base/org.debian/sys", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/usr"}, nePrefix+"/var/lib/hakurei/base/org.debian/usr", nil),
+			call("evalSymlinks", stub.ExpectArgs{"/var/lib/hakurei/base/org.debian/var"}, nePrefix+"/var/lib/hakurei/base/org.debian/var", nil),
+		}, newI().
+			Ensure(m("/var/lib/hakurei/u0"), 0700).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0"),
+				acl.Execute).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0/org.chromium.Chromium"),
+				acl.Read, acl.Write, acl.Execute), nil, nil, insertsOps(needsApplyState(func(state *outcomeStateParams) {
+			state.filesystem = config.Container.Filesystem[1:]
+		})), []stub.Call{
+			// this op configures the container state and does not make calls during toContainer
+		}, &container.Params{
+			Env: []string{
+				"GOOGLE_API_KEY=AIzaSyBHDrl33hwRp4rMQY0ziRbj8K9LPA6vUCY",
+				"GOOGLE_DEFAULT_CLIENT_ID=77185425430.apps.googleusercontent.com",
+				"GOOGLE_DEFAULT_CLIENT_SECRET=OTJgUOQcT7lO7GsGZq2G4IlT",
+			},
+
+			Ops: new(container.Ops).
+				Etc(fhs.AbsEtc, wantAutoEtcPrefix).
+				Tmpfs(fhs.AbsTmp, 0, 0755).
+				Overlay(
+					check.MustAbs("/nix/store"),
+					fhs.AbsVarLib.Append("hakurei/nix/u0/org.chromium.Chromium/rw-store/upper"),
+					fhs.AbsVarLib.Append("hakurei/nix/u0/org.chromium.Chromium/rw-store/work"),
+					fhs.AbsVarLib.Append("hakurei/base/org.nixos/ro-store")).
+				Link(fhs.AbsRun.Append("current-system"), "/run/current-system", true).
+				Link(fhs.AbsRun.Append("opengl-driver"), "/run/opengl-driver", true).
+				Bind(
+					fhs.AbsVarLib.Append("hakurei/u0/org.chromium.Chromium"),
+					check.MustAbs("/data/data/org.chromium.Chromium"),
+					comp.BindWritable|comp.BindEnsure).
+				Bind(fhs.AbsDev.Append("dri"), fhs.AbsDev.Append("dri"), comp.BindDevice|comp.BindWritable|comp.BindOptional).
+				Remount(fhs.AbsRoot, syscall.MS_RDONLY),
+		}, nil, nil},
+	})
+}
+
+func TestFlattenExtraPerms(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name  string
+		perms []hst.ExtraPermConfig
+		want  *system.I
+	}{
+		{"path nil check", append(hst.Template().ExtraPerms, hst.ExtraPermConfig{}), newI().
+			Ensure(m("/var/lib/hakurei/u0"), 0700).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0"),
+				acl.Execute).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0/org.chromium.Chromium"),
+				acl.Read, acl.Write, acl.Execute)},
+
+		{"template", hst.Template().ExtraPerms, newI().
+			Ensure(m("/var/lib/hakurei/u0"), 0700).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0"),
+				acl.Execute).
+			UpdatePermType(system.User, m("/var/lib/hakurei/u0/org.chromium.Chromium"),
+				acl.Read, acl.Write, acl.Execute)},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := newI()
+			flattenExtraPerms(got, tc.perms)
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("flattenExtraPerms: sys = %#v, want %#v", got, tc.want)
+			}
+		})
+	}
+}
+
+// invalidFSHost implements the Host method of [hst.FilesystemConfig] with an invalid response.
+type invalidFSHost bool
+
+func (f invalidFSHost) Valid() bool           { return bool(f) }
+func (invalidFSHost) Path() *check.Absolute   { panic("unreachable") }
+func (invalidFSHost) Host() []*check.Absolute { return []*check.Absolute{nil} }
+func (invalidFSHost) Apply(*hst.ApplyState)   { panic("unreachable") }
+func (invalidFSHost) String() string          { panic("unreachable") }