| 1 | package rootstate |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "os" |
| 7 | "path/filepath" |
| 8 | "strings" |
| 9 | "testing" |
| 10 | "time" |
| 11 | |
| 12 | "golang.org/x/sys/unix" |
| 13 | ) |
| 14 | |
| 15 | func fixture(t *testing.T) (string, Store) { |
| 16 | t.Helper() |
| 17 | parent := t.TempDir() |
| 18 | if err := os.Chmod(parent, 0700); err != nil { |
| 19 | t.Fatal(err) |
| 20 | } |
| 21 | f, err := os.Open(parent) |
| 22 | if err != nil { |
| 23 | t.Fatal(err) |
| 24 | } |
| 25 | defer f.Close() |
| 26 | d, err := descend(f, []string{"trusted"}, true, false, uint32(os.Geteuid())) |
| 27 | if err != nil { |
| 28 | t.Fatal(err) |
| 29 | } |
| 30 | t.Cleanup(func() { d.Close() }) |
| 31 | return filepath.Join(parent, "trusted"), d |
| 32 | } |
| 33 | |
| 34 | func TestPlan14HostileOwnership(t *testing.T) { |
| 35 | if os.Geteuid() == 0 { |
| 36 | t.Skip("nonroot witness; root ownership substitution is covered separately") |
| 37 | } |
| 38 | path, _ := fixture(t) |
| 39 | if _, err := Open(path, false, false); err == nil { |
| 40 | t.Fatal("root trusted real non-root-owned ancestors") |
| 41 | } |
| 42 | f, err := os.Create(filepath.Join(path, "file")) |
| 43 | if err != nil { |
| 44 | t.Fatal(err) |
| 45 | } |
| 46 | defer f.Close() |
| 47 | if err := trusted(int(f.Fd()), 0, unix.S_IFREG); !errors.Is(err, os.ErrPermission) { |
| 48 | t.Fatalf("real non-root-owned leaf accepted: %v", err) |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | func TestPlan14SymlinksHardlinksFIFOAndModes(t *testing.T) { |
| 53 | for _, attack := range []string{"leaf-link", "hardlink", "fifo", "writable", "directory-writable", "ancestor-link"} { |
| 54 | t.Run(attack, func(t *testing.T) { |
| 55 | path, d := fixture(t) |
| 56 | leaf := filepath.Join(path, "record") |
| 57 | switch attack { |
| 58 | case "leaf-link": |
| 59 | if err := os.Symlink("missing", leaf); err != nil { |
| 60 | t.Fatal(err) |
| 61 | } |
| 62 | case "hardlink": |
| 63 | if err := d.Write("other", []byte("safe")); err != nil { |
| 64 | t.Fatal(err) |
| 65 | } |
| 66 | if err := os.Link(filepath.Join(path, "other"), leaf); err != nil { |
| 67 | t.Fatal(err) |
| 68 | } |
| 69 | case "fifo": |
| 70 | if err := unix.Mkfifo(leaf, 0600); err != nil { |
| 71 | t.Fatal(err) |
| 72 | } |
| 73 | case "writable": |
| 74 | if err := os.WriteFile(leaf, []byte("false proof"), 0600); err != nil { |
| 75 | t.Fatal(err) |
| 76 | } |
| 77 | if err := os.Chmod(leaf, 0666); err != nil { |
| 78 | t.Fatal(err) |
| 79 | } |
| 80 | case "directory-writable": |
| 81 | if err := d.Write("record", []byte("safe")); err != nil { |
| 82 | t.Fatal(err) |
| 83 | } |
| 84 | if err := os.Chmod(path, 0777); err != nil { |
| 85 | t.Fatal(err) |
| 86 | } |
| 87 | case "ancestor-link": |
| 88 | parent, err := os.Open(filepath.Dir(path)) |
| 89 | if err != nil { |
| 90 | t.Fatal(err) |
| 91 | } |
| 92 | defer parent.Close() |
| 93 | if err := os.Symlink("trusted", filepath.Join(filepath.Dir(path), "alias")); err != nil { |
| 94 | t.Fatal(err) |
| 95 | } |
| 96 | if got, err := descend(parent, []string{"alias"}, false, false, uint32(os.Geteuid())); err == nil { |
| 97 | got.Close() |
| 98 | t.Fatal("followed ancestor") |
| 99 | } |
| 100 | return |
| 101 | } |
| 102 | if _, err := d.Read("record"); err == nil { |
| 103 | t.Fatal("read accepted hostile file") |
| 104 | } |
| 105 | if err := d.Write("record", []byte("replacement")); err == nil { |
| 106 | t.Fatal("write repaired hostile file") |
| 107 | } |
| 108 | }) |
| 109 | } |
| 110 | } |
| 111 | |
| 112 | func TestPlan14RenameKeepsDescriptor(t *testing.T) { |
| 113 | path, d := fixture(t) |
| 114 | if err := d.Write("record", []byte("original")); err != nil { |
| 115 | t.Fatal(err) |
| 116 | } |
| 117 | moved := path + "-old" |
| 118 | if err := os.Rename(path, moved); err != nil { |
| 119 | t.Fatal(err) |
| 120 | } |
| 121 | if err := os.Mkdir(path, 0700); err != nil { |
| 122 | t.Fatal(err) |
| 123 | } |
| 124 | if err := os.WriteFile(filepath.Join(path, "record"), []byte("forged"), 0600); err != nil { |
| 125 | t.Fatal(err) |
| 126 | } |
| 127 | b, err := d.Read("record") |
| 128 | if err != nil || string(b) != "original" { |
| 129 | t.Fatalf("%q %v", b, err) |
| 130 | } |
| 131 | if err := d.Write("record", []byte("updated")); err != nil { |
| 132 | t.Fatal(err) |
| 133 | } |
| 134 | b, err = os.ReadFile(filepath.Join(path, "record")) |
| 135 | if err != nil || string(b) != "forged" { |
| 136 | t.Fatalf("touched replacement: %q %v", b, err) |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | func TestPlan14LockAndLimits(t *testing.T) { |
| 141 | _, d := fixture(t) |
| 142 | unlock, err := d.Lock(t.Context(), "host.lock") |
| 143 | if err != nil { |
| 144 | t.Fatal(err) |
| 145 | } |
| 146 | ctx, cancel := context.WithTimeout(t.Context(), 20*time.Millisecond) |
| 147 | defer cancel() |
| 148 | if release, err := d.Lock(ctx, "host.lock"); err == nil { |
| 149 | release() |
| 150 | t.Fatal("split lock") |
| 151 | } else if !errors.Is(err, context.DeadlineExceeded) { |
| 152 | t.Fatal(err) |
| 153 | } |
| 154 | unlock() |
| 155 | unlock, err = d.Lock(t.Context(), "host.lock") |
| 156 | if err != nil { |
| 157 | t.Fatal(err) |
| 158 | } |
| 159 | unlock() |
| 160 | if err := d.Write("large", []byte(strings.Repeat("x", MaxRecord+1))); err == nil { |
| 161 | t.Fatal("unbounded write") |
| 162 | } |
| 163 | if err := d.Write("../escape", []byte("x")); err == nil { |
| 164 | t.Fatal("escaped store") |
| 165 | } |
| 166 | for i := 0; i < 2; i++ { |
| 167 | names, err := d.Names() |
| 168 | if err != nil || len(names) != 1 { |
| 169 | t.Fatalf("scan %d: %v %v", i, names, err) |
| 170 | } |
| 171 | } |
| 172 | } |
| 173 | |
| 174 | func TestPlan14RootOwnedParentRejectsServiceLeaf(t *testing.T) { |
| 175 | if os.Geteuid() != 0 { |
| 176 | t.Skip("requires uid 0 and chown; run in disposable root-owned test root") |
| 177 | } |
| 178 | path, d := fixture(t) |
| 179 | if err := d.Write("record", []byte("forged")); err != nil { |
| 180 | t.Fatal(err) |
| 181 | } |
| 182 | if err := os.Chown(filepath.Join(path, "record"), 65534, 65534); err != nil { |
| 183 | t.Fatal(err) |
| 184 | } |
| 185 | if _, err := d.Read("record"); !errors.Is(err, os.ErrPermission) { |
| 186 | t.Fatalf("%v", err) |
| 187 | } |
| 188 | if err := d.Write("record", []byte("replacement")); !errors.Is(err, os.ErrPermission) { |
| 189 | t.Fatalf("%v", err) |
| 190 | } |
| 191 | } |
| 192 | |
| 193 | func TestPlan14DescendRetriesEveryAncestorSync(t *testing.T) { |
| 194 | for failAt := 1; failAt <= 3; failAt++ { |
| 195 | t.Run(string(rune('0'+failAt)), func(t *testing.T) { |
| 196 | base := t.TempDir() |
| 197 | if err := os.Chmod(base, 0700); err != nil { |
| 198 | t.Fatal(err) |
| 199 | } |
| 200 | parent, err := os.Open(base) |
| 201 | if err != nil { |
| 202 | t.Fatal(err) |
| 203 | } |
| 204 | defer parent.Close() |
| 205 | parts := []string{"a", "b", "c"} |
| 206 | calls := 0 |
| 207 | injected := errors.New("parent fsync") |
| 208 | _, err = descendSync(parent, parts, true, false, uint32(os.Geteuid()), func(fd int) error { |
| 209 | calls++ |
| 210 | if calls == failAt { |
| 211 | return injected |
| 212 | } |
| 213 | return unix.Fsync(fd) |
| 214 | }) |
| 215 | if !errors.Is(err, injected) { |
| 216 | t.Fatalf("first traversal: %v", err) |
| 217 | } |
| 218 | if _, err := os.Stat(filepath.Join(append([]string{base}, parts[:failAt]...)...)); err != nil { |
| 219 | t.Fatal(err) |
| 220 | } |
| 221 | calls = 0 |
| 222 | d, err := descendSync(parent, parts, true, false, uint32(os.Geteuid()), func(fd int) error { |
| 223 | calls++ |
| 224 | return unix.Fsync(fd) |
| 225 | }) |
| 226 | if err != nil { |
| 227 | t.Fatal(err) |
| 228 | } |
| 229 | defer d.Close() |
| 230 | if calls != len(parts) { |
| 231 | t.Fatalf("retry synced %d parents, want %d", calls, len(parts)) |
| 232 | } |
| 233 | if err := d.Write("record", []byte("durable")); err != nil { |
| 234 | t.Fatal(err) |
| 235 | } |
| 236 | // Even an all-existing path must still propagate a sync failure. |
| 237 | _, err = descendSync(parent, parts, true, false, uint32(os.Geteuid()), func(int) error { return injected }) |
| 238 | if !errors.Is(err, injected) { |
| 239 | t.Fatalf("existing traversal: %v", err) |
| 240 | } |
| 241 | }) |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | func TestPlan14RemoveCapability(t *testing.T) { |
| 246 | path, s := fixture(t) |
| 247 | if err := s.Write("capability", []byte("secret")); err != nil { |
| 248 | t.Fatal(err) |
| 249 | } |
| 250 | if err := s.Remove("capability"); err != nil { |
| 251 | t.Fatal(err) |
| 252 | } |
| 253 | if _, err := s.Read("capability"); !errors.Is(err, os.ErrNotExist) { |
| 254 | t.Fatal(err) |
| 255 | } |
| 256 | if err := s.Remove("capability"); err != nil { |
| 257 | t.Fatal(err) |
| 258 | } |
| 259 | if err := s.Remove("../escape"); err == nil { |
| 260 | t.Fatal("escaped") |
| 261 | } |
| 262 | if err := os.Symlink("outside", filepath.Join(path, "capability")); err != nil { |
| 263 | t.Fatal(err) |
| 264 | } |
| 265 | if err := s.Remove("capability"); err == nil { |
| 266 | t.Fatal("removed untrusted entry") |
| 267 | } |
| 268 | } |
| 269 | |
amadan