test/sandbox: check fs outcome

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

test/configuration.nix

@@ -70,7 +70,7 @@
       echo 'output Virtual-1 res 1680x1050') > ~/.config/sway/config
 
       sway --validate
-      systemd-cat --identifier=sway sway && touch /tmp/sway-exit-ok
+      systemd-cat --identifier=session sway && touch /tmp/sway-exit-ok
     fi
   '';
 

test/sandbox/assert.go

@@ -2,17 +2,30 @@ package sandbox
 
 import (
 	"encoding/json"
+	"io/fs"
 	"log"
 	"os"
 )
 
 var (
 	assert     = log.New(os.Stderr, "sandbox: ", 0)
+	printfFunc = assert.Printf
 	fatalfFunc = assert.Fatalf
 )
 
+func printf(format string, v ...any) { printfFunc(format, v...) }
 func fatalf(format string, v ...any) { fatalfFunc(format, v...) }
 
+func mustDecode(wantFile string, v any) {
+	if f, err := os.Open(wantFile); err != nil {
+		fatalf("cannot open %q: %v", wantFile, err)
+	} else if err = json.NewDecoder(f).Decode(v); err != nil {
+		fatalf("cannot decode %q: %v", wantFile, err)
+	} else if err = f.Close(); err != nil {
+		fatalf("cannot close %q: %v", wantFile, err)
+	}
+}
+
 func MustAssertMounts(name, hostMountsFile, wantFile string) {
 	hostMounts := make([]*Mntent, 0, 128)
 	if err := IterMounts(hostMountsFile, func(e *Mntent) {
@@ -22,13 +35,7 @@ func MustAssertMounts(name, hostMountsFile, wantFile string) {
 	}
 
 	var want []Mntent
-	if f, err := os.Open(wantFile); err != nil {
-		fatalf("cannot open %q: %v", wantFile, err)
-	} else if err = json.NewDecoder(f).Decode(&want); err != nil {
-		fatalf("cannot decode %q: %v", wantFile, err)
-	} else if err = f.Close(); err != nil {
-		fatalf("cannot close %q: %v", wantFile, err)
-	}
+	mustDecode(wantFile, &want)
 
 	for i := range want {
 		if want[i].Opts == "host_passthrough" {
@@ -53,9 +60,21 @@ func MustAssertMounts(name, hostMountsFile, wantFile string) {
 				e, &want[i])
 		}
 
-		assert.Printf("%s", e)
+		printf("%s", e)
 		i++
 	}); err != nil {
 		fatalf("cannot iterate mounts: %v", err)
 	}
 }
+
+func MustAssertFS(e fs.FS, wantFile string) {
+	var want *FS
+	mustDecode(wantFile, &want)
+	if want == nil {
+		fatalf("invalid payload")
+	}
+
+	if err := want.Compare(".", e); err != nil {
+		fatalf("%v", err)
+	}
+}

test/sandbox/assert_test.go

@@ -1,3 +1,32 @@
 package sandbox
 
-func ReplaceFatal(f func(format string, v ...any)) { fatalfFunc = f }
+import (
+	"encoding/json"
+	"os"
+	"path"
+	"testing"
+)
+
+type F func(format string, v ...any)
+
+func SwapPrint(f F) (old F) { old = printfFunc; printfFunc = f; return }
+func SwapFatal(f F) (old F) { old = fatalfFunc; fatalfFunc = f; return }
+
+func MustWantFile(t *testing.T, v any) (wantFile string) {
+	wantFile = path.Join(t.TempDir(), "want.json")
+	if f, err := os.OpenFile(wantFile, os.O_CREATE|os.O_WRONLY, 0400); err != nil {
+		t.Fatalf("cannot create %q: %v", wantFile, err)
+	} else if err = json.NewEncoder(f).Encode(v); err != nil {
+		t.Fatalf("cannot encode to %q: %v", wantFile, err)
+	} else if err = f.Close(); err != nil {
+		t.Fatalf("cannot close %q: %v", wantFile, err)
+	}
+
+	t.Cleanup(func() {
+		if err := os.Remove(wantFile); err != nil {
+			t.Fatalf("cannot remove %q: %v", wantFile, err)
+		}
+	})
+
+	return
+}

test/sandbox/default.nix

@@ -7,6 +7,7 @@
 writeShellScript "check-sandbox" ''
   set -e
   ${callPackage ./mount.nix { inherit version; }}/bin/test
+  ${callPackage ./fs.nix { inherit version; }}/bin/test
 
   touch /tmp/sandbox-ok
 ''

test/sandbox/fs.go

@@ -0,0 +1,98 @@
+package sandbox
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"path"
+	"strings"
+)
+
+var (
+	ErrFSBadLength  = errors.New("bad dir length")
+	ErrFSBadData    = errors.New("data differs")
+	ErrFSBadMode    = errors.New("mode differs")
+	ErrFSInvalidEnt = errors.New("invalid entry condition")
+)
+
+type FS struct {
+	Mode fs.FileMode    `json:"mode"`
+	Dir  map[string]*FS `json:"dir"`
+	Data *string        `json:"data"`
+}
+
+func printDir(prefix string, dir []fs.DirEntry) {
+	names := make([]string, len(dir))
+	for i, ent := range dir {
+		name := ent.Name()
+		if ent.IsDir() {
+			name += "/"
+		}
+		names[i] = fmt.Sprintf("%q", name)
+	}
+	printf("[FAIL] d %q: %s", prefix, strings.Join(names, " "))
+}
+
+func (s *FS) Compare(prefix string, e fs.FS) error {
+	if s.Data != nil {
+		if s.Dir != nil {
+			panic("invalid state")
+		}
+		panic("invalid compare call")
+	}
+
+	if s.Dir == nil {
+		printf("[ OK ] s %s", prefix)
+		return nil
+	}
+
+	var dir []fs.DirEntry
+	if d, err := fs.ReadDir(e, prefix); err != nil {
+		return err
+	} else if len(d) != len(s.Dir) {
+		printDir(prefix, d)
+		return ErrFSBadLength
+	} else {
+		dir = d
+	}
+
+	for _, got := range dir {
+		name := got.Name()
+
+		if want, ok := s.Dir[name]; !ok {
+			printDir(prefix, dir)
+			return fs.ErrNotExist
+		} else if want.Dir != nil && !got.IsDir() {
+			printDir(prefix, dir)
+			return ErrFSInvalidEnt
+		} else {
+			name = path.Join(prefix, name)
+
+			if fi, err := got.Info(); err != nil {
+				return err
+			} else if fi.Mode() != want.Mode {
+				printf("[FAIL] m %q: %x, want %x",
+					name, uint32(fi.Mode()), uint32(want.Mode))
+				return ErrFSBadMode
+			}
+
+			if want.Data != nil {
+				if want.Dir != nil {
+					panic("invalid state")
+				}
+				if v, err := fs.ReadFile(e, name); err != nil {
+					return err
+				} else if string(v) != *want.Data {
+					printf("[FAIL] f %s", name)
+					return ErrFSBadData
+				}
+				printf("[ OK ] f %s", name)
+			} else if err := want.Compare(name, e); err != nil {
+				return err
+			}
+		}
+	}
+	printf("[ OK ] d %s", prefix)
+
+	return nil
+}

test/sandbox/fs.nix

@@ -0,0 +1,214 @@
+{
+  lib,
+  writeText,
+  buildGoModule,
+
+  version,
+}:
+let
+  wantFS =
+    let
+      fs = mode: dir: data: {
+        mode = lib.fromHexString mode;
+        inherit
+          dir
+          data
+          ;
+      };
+    in
+    fs "dead" {
+      ".fortify" = fs "800001ed" {
+        etc = fs "800001ed" null null;
+        sbin = fs "800001c0" {
+          fortify = fs "16d" null null;
+          init = fs "80001ff" null null;
+        } null;
+        host-mounts = fs "124" null null;
+      } null;
+      bin = fs "800001ed" { sh = fs "80001ff" null null; } null;
+      dev = fs "800001ed" {
+        core = fs "80001ff" null null;
+        dri = fs "800001ed" {
+          by-path = fs "800001ed" {
+            "pci-0000:00:09.0-card" = fs "80001ff" null null;
+            "pci-0000:00:09.0-render" = fs "80001ff" null null;
+          } null;
+          card0 = fs "42001b0" null null;
+          renderD128 = fs "42001b6" null null;
+        } null;
+        fd = fs "80001ff" null null;
+        full = fs "42001b6" null null;
+        mqueue = fs "801001ff" { } null;
+        null = fs "42001b6" null "";
+        ptmx = fs "80001ff" null null;
+        pts = fs "800001ed" { ptmx = fs "42001b6" null null; } null;
+        random = fs "42001b6" null null;
+        shm = fs "800001ed" { } null;
+        stderr = fs "80001ff" null null;
+        stdin = fs "80001ff" null null;
+        stdout = fs "80001ff" null null;
+        tty = fs "42001b6" null null;
+        urandom = fs "42001b6" null null;
+        zero = fs "42001b6" null null;
+      } null;
+      etc = fs "800001c0" {
+        ".clean" = fs "80001ff" null null;
+        ".updated" = fs "80001ff" null null;
+        "NIXOS" = fs "80001ff" null null;
+        "X11" = fs "80001ff" null null;
+        "alsa" = fs "80001ff" null null;
+        "bashrc" = fs "80001ff" null null;
+        "binfmt.d" = fs "80001ff" null null;
+        "dbus-1" = fs "80001ff" null null;
+        "default" = fs "80001ff" null null;
+        "dhcpcd.exit-hook" = fs "80001ff" null null;
+        "fonts" = fs "80001ff" null null;
+        "fstab" = fs "80001ff" null null;
+        "fsurc" = fs "80001ff" null null;
+        "fuse.conf" = fs "80001ff" null null;
+        "group" = fs "180" null "fortify:x:65534:\n";
+        "host.conf" = fs "80001ff" null null;
+        "hostname" = fs "80001ff" null null;
+        "hosts" = fs "80001ff" null null;
+        "inputrc" = fs "80001ff" null null;
+        "issue" = fs "80001ff" null null;
+        "kbd" = fs "80001ff" null null;
+        "locale.conf" = fs "80001ff" null null;
+        "login.defs" = fs "80001ff" null null;
+        "lsb-release" = fs "80001ff" null null;
+        "lvm" = fs "80001ff" null null;
+        "machine-id" = fs "80001ff" null null;
+        "man_db.conf" = fs "80001ff" null null;
+        "modprobe.d" = fs "80001ff" null null;
+        "modules-load.d" = fs "80001ff" null null;
+        "mtab" = fs "80001ff" null null;
+        "nanorc" = fs "80001ff" null null;
+        "netgroup" = fs "80001ff" null null;
+        "nix" = fs "80001ff" null null;
+        "nixos" = fs "80001ff" null null;
+        "nscd.conf" = fs "80001ff" null null;
+        "nsswitch.conf" = fs "80001ff" null null;
+        "os-release" = fs "80001ff" null null;
+        "pam" = fs "80001ff" null null;
+        "pam.d" = fs "80001ff" null null;
+        "passwd" = fs "180" null "u0_a1:x:65534:65534:Fortify:/var/lib/fortify/u0/a1:/run/current-system/sw/bin/bash\n";
+        "pipewire" = fs "80001ff" null null;
+        "pki" = fs "80001ff" null null;
+        "polkit-1" = fs "80001ff" null null;
+        "profile" = fs "80001ff" null null;
+        "profiles" = fs "80001ff" null null;
+        "protocols" = fs "80001ff" null null;
+        "resolv.conf" = fs "80001ff" null null;
+        "resolvconf.conf" = fs "80001ff" null null;
+        "rpc" = fs "80001ff" null null;
+        "services" = fs "80001ff" null null;
+        "set-environment" = fs "80001ff" null null;
+        "shadow" = fs "80001ff" null null;
+        "shells" = fs "80001ff" null null;
+        "ssh" = fs "80001ff" null null;
+        "ssl" = fs "80001ff" null null;
+        "static" = fs "80001ff" null null;
+        "subgid" = fs "80001ff" null null;
+        "subuid" = fs "80001ff" null null;
+        "sudoers" = fs "80001ff" null null;
+        "sway" = fs "80001ff" null null;
+        "sysctl.d" = fs "80001ff" null null;
+        "systemd" = fs "80001ff" null null;
+        "terminfo" = fs "80001ff" null null;
+        "tmpfiles.d" = fs "80001ff" null null;
+        "udev" = fs "80001ff" null null;
+        "vconsole.conf" = fs "80001ff" null null;
+        "xdg" = fs "80001ff" null null;
+        "zoneinfo" = fs "80001ff" null null;
+      } null;
+      nix = fs "800001c0" { store = fs "801001fd" null null; } null;
+      proc = fs "8000016d" null null;
+      run = fs "800001c0" {
+        current-system = fs "8000016d" null null;
+        opengl-driver = fs "8000016d" null null;
+        user = fs "800001ed" {
+          "65534" = fs "800001ed" {
+            bus = fs "10001fd" null null;
+            pulse = fs "800001c0" { native = fs "10001b6" null null; } null;
+            wayland-0 = fs "1000038" null null;
+          } null;
+        } null;
+      } null;
+      sys = fs "800001c0" {
+        block = fs "800001ed" {
+          fd0 = fs "80001ff" null null;
+          loop0 = fs "80001ff" null null;
+          loop1 = fs "80001ff" null null;
+          loop2 = fs "80001ff" null null;
+          loop3 = fs "80001ff" null null;
+          loop4 = fs "80001ff" null null;
+          loop5 = fs "80001ff" null null;
+          loop6 = fs "80001ff" null null;
+          loop7 = fs "80001ff" null null;
+          sr0 = fs "80001ff" null null;
+          vda = fs "80001ff" null null;
+        } null;
+        bus = fs "800001ed" null null;
+        class = fs "800001ed" null null;
+        dev = fs "800001ed" {
+          block = fs "800001ed" null null;
+          char = fs "800001ed" null null;
+        } null;
+        devices = fs "800001ed" null null;
+      } null;
+      tmp = fs "800001f8" { } null;
+      usr = fs "800001c0" { bin = fs "800001ed" { env = fs "80001ff" null null; } null; } null;
+      var = fs "800001c0" {
+        lib = fs "800001c0" {
+          fortify = fs "800001c0" {
+            u0 = fs "800001c0" {
+              a1 = fs "800001c0" {
+                ".cache" = fs "800001ed" { ".keep" = fs "80001ff" null ""; } null;
+                ".config" = fs "800001ed" { "environment.d" = fs "800001ed" { "10-home-manager.conf" = fs "80001ff" null null; } null; } null;
+                ".local" = fs "800001ed" {
+                  state = fs "800001ed" {
+                    home-manager = fs "800001ed" { gcroots = fs "800001ed" { current-home = fs "80001ff" null null; } null; } null;
+                    nix = fs "800001ed" {
+                      profiles = fs "800001ed" {
+                        home-manager = fs "80001ff" null null;
+                        home-manager-1-link = fs "80001ff" null null;
+                        profile = fs "80001ff" null null;
+                        profile-1-link = fs "80001ff" null null;
+                      } null;
+                    } null;
+                  } null;
+                } null;
+                ".nix-defexpr" = fs "800001ed" {
+                  channels = fs "80001ff" null null;
+                  channels_root = fs "80001ff" null null;
+                } null;
+                ".nix-profile" = fs "80001ff" null null;
+              } null;
+            } null;
+          } null;
+        } null;
+        run = fs "800001ed" { nscd = fs "800001ed" { } null; } null;
+      } null;
+    } null;
+
+  mainFile = writeText "main.go" ''
+    package main
+
+    import "os"
+    import "git.gensokyo.uk/security/fortify/test/sandbox"
+
+    func main() { sandbox.MustAssertFS(os.DirFS("/"), "${writeText "want-fs.json" (builtins.toJSON wantFS)}") }
+  '';
+in
+buildGoModule {
+  pname = "check-fs";
+  inherit version;
+
+  src = ../.;
+  vendorHash = null;
+
+  preBuild = ''
+    go mod init git.gensokyo.uk/security/fortify/test >& /dev/null
+    cp ${mainFile} main.go
+  '';
+}

test/sandbox/fs_test.go

@@ -0,0 +1,84 @@
+package sandbox_test
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"strings"
+	"testing"
+	"testing/fstest"
+
+	"git.gensokyo.uk/security/fortify/test/sandbox"
+)
+
+var (
+	fsPasswdSample = "u0_a20:x:65534:65534:Fortify:/var/lib/persist/module/fortify/u0/a20:/run/current-system/sw/bin/zsh"
+	fsGroupSample  = "fortify:x:65534:"
+)
+
+func TestCompare(t *testing.T) {
+	testCases := []struct {
+		name string
+
+		sample  fstest.MapFS
+		want    *sandbox.FS
+		wantOut string
+		wantErr error
+	}{
+		{"skip", fstest.MapFS{}, &sandbox.FS{}, "[ OK ] s .\x00", nil},
+		{"simple pass", fstest.MapFS{".fortify": {Mode: 0x800001ed}},
+			&sandbox.FS{Dir: map[string]*sandbox.FS{".fortify": {Mode: 0x800001ed}}},
+			"[ OK ] s .fortify\x00[ OK ] d .\x00", nil},
+		{"bad length", fstest.MapFS{".fortify": {Mode: 0x800001ed}},
+			&sandbox.FS{Dir: make(map[string]*sandbox.FS)},
+			"[FAIL] d \".\": \".fortify/\"\x00", sandbox.ErrFSBadLength},
+		{"top level bad mode", fstest.MapFS{".fortify": {Mode: 0x800001ed}},
+			&sandbox.FS{Dir: map[string]*sandbox.FS{".fortify": {Mode: 0xdeadbeef}}},
+			"[FAIL] m \".fortify\": 800001ed, want deadbeef\x00", sandbox.ErrFSBadMode},
+		{"invalid entry condition", fstest.MapFS{"test": {Data: []byte{'0'}, Mode: 0644}},
+			&sandbox.FS{Dir: map[string]*sandbox.FS{"test": {Dir: make(map[string]*sandbox.FS)}}},
+			"[FAIL] d \".\": \"test\"\x00", sandbox.ErrFSInvalidEnt},
+		{"nonexistent", fstest.MapFS{"test": {Data: []byte{'0'}, Mode: 0644}},
+			&sandbox.FS{Dir: map[string]*sandbox.FS{".test": {}}},
+			"[FAIL] d \".\": \"test\"\x00", fs.ErrNotExist},
+		{"file", fstest.MapFS{"etc": {Mode: 0x800001c0},
+			"etc/passwd": {Data: []byte(fsPasswdSample), Mode: 0644},
+			"etc/group":  {Data: []byte(fsGroupSample), Mode: 0644},
+		}, &sandbox.FS{Dir: map[string]*sandbox.FS{"etc": {Mode: 0x800001c0, Dir: map[string]*sandbox.FS{
+			"passwd": {Mode: 0x1a4, Data: &fsPasswdSample},
+			"group":  {Mode: 0x1a4, Data: &fsGroupSample},
+		}}}}, "[ OK ] f etc/group\x00[ OK ] f etc/passwd\x00[ OK ] d etc\x00[ OK ] d .\x00", nil},
+		{"file differ", fstest.MapFS{"etc": {Mode: 0x800001c0},
+			"etc/passwd": {Data: []byte(fsPasswdSample), Mode: 0644},
+			"etc/group":  {Data: []byte(fsGroupSample), Mode: 0644},
+		}, &sandbox.FS{Dir: map[string]*sandbox.FS{"etc": {Mode: 0x800001c0, Dir: map[string]*sandbox.FS{
+			"passwd": {Mode: 0x1a4, Data: &fsGroupSample},
+			"group":  {Mode: 0x1a4, Data: &fsGroupSample},
+		}}}}, "[ OK ] f etc/group\x00[FAIL] f etc/passwd\x00", sandbox.ErrFSBadData},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			gotOut := new(strings.Builder)
+			oldPrint := sandbox.SwapPrint(func(format string, v ...any) { _, _ = fmt.Fprintf(gotOut, format+"\x00", v...) })
+			t.Cleanup(func() { sandbox.SwapPrint(oldPrint) })
+
+			err := tc.want.Compare(".", tc.sample)
+			if !errors.Is(err, tc.wantErr) {
+				t.Errorf("Compare: error = %v; wantErr %v",
+					err, tc.wantErr)
+			}
+
+			if gotOut.String() != tc.wantOut {
+				t.Errorf("Compare: output %q; want %q",
+					gotOut, tc.wantOut)
+			}
+		})
+	}
+
+	t.Run("assert", func(t *testing.T) {
+		oldFatal := sandbox.SwapFatal(t.Fatalf)
+		t.Cleanup(func() { sandbox.SwapFatal(oldFatal) })
+		sandbox.MustAssertFS(make(fstest.MapFS), sandbox.MustWantFile(t, &sandbox.FS{Mode: 0xDEADBEEF}))
+	})
+}

test/sandbox/mount_test.go

@@ -1,7 +1,6 @@
 package sandbox_test
 
 import (
-	"encoding/json"
 	"os"
 	"path"
 	"testing"
@@ -111,22 +110,9 @@ overlay /.fortify/sbin/fortify overlay ro,nosuid,nodev,relatime,lowerdir=/mnt-ro
 		})
 
 		t.Run(tc.name+" assert", func(t *testing.T) {
-			sandbox.ReplaceFatal(t.Fatalf)
-
-			wantFile := path.Join(t.TempDir(), "want.json")
-			if f, err := os.OpenFile(wantFile, os.O_CREATE|os.O_WRONLY, 0400); err != nil {
-				t.Fatalf("cannot create %q: %v", wantFile, err)
-			} else if err = json.NewEncoder(f).Encode(tc.want); err != nil {
-				t.Fatalf("cannot encode to %q: %v", wantFile, err)
-			} else if err = f.Close(); err != nil {
-				t.Fatalf("cannot close %q: %v", wantFile, err)
-			}
-
-			sandbox.MustAssertMounts(name, name, wantFile)
-
-			if err := os.Remove(wantFile); err != nil {
-				t.Fatalf("cannot remove %q: %v", wantFile, err)
-			}
+			oldFatal := sandbox.SwapFatal(t.Fatalf)
+			t.Cleanup(func() { sandbox.SwapFatal(oldFatal) })
+			sandbox.MustAssertMounts(name, name, sandbox.MustWantFile(t, tc.want))
 		})
 
 		if err := os.Remove(name); err != nil {