| 1 | //go:build linux |
| 2 | |
| 3 | package host |
| 4 | |
| 5 | import ( |
| 6 | "context" |
| 7 | "errors" |
| 8 | "fmt" |
| 9 | "io/fs" |
| 10 | "maps" |
| 11 | "os" |
| 12 | "path/filepath" |
| 13 | "slices" |
| 14 | "syscall" |
| 15 | "testing" |
| 16 | |
| 17 | "golang.org/x/sys/unix" |
| 18 | ) |
| 19 | |
| 20 | // floorDirsOpt is an opt directory with system/ and system/guard at 0755, |
| 21 | // as guard-arm leaves them, reached with no symlink on the way. The tests |
| 22 | // walk from opt itself as the base, owned by the test's own uid and made |
| 23 | // 0755 whatever the test's umask: the real ancestors of a scratch directory |
| 24 | // are not the test's. |
| 25 | func floorDirsOpt(t *testing.T) string { |
| 26 | t.Helper() |
| 27 | opt, err := filepath.EvalSymlinks(t.TempDir()) |
| 28 | if err != nil { |
| 29 | t.Fatal(err) |
| 30 | } |
| 31 | guard := systemGuardDir(opt) |
| 32 | if err := os.MkdirAll(guard, 0o755); err != nil { |
| 33 | t.Fatal(err) |
| 34 | } |
| 35 | for _, dir := range []string{opt, filepath.Join(opt, "system"), guard} { |
| 36 | if err := os.Chmod(dir, 0o755); err != nil { |
| 37 | t.Fatal(err) |
| 38 | } |
| 39 | } |
| 40 | return opt |
| 41 | } |
| 42 | |
| 43 | func floorDirMode(t *testing.T, dir string) os.FileMode { |
| 44 | t.Helper() |
| 45 | st, err := os.Lstat(dir) |
| 46 | if err != nil { |
| 47 | t.Fatal(err) |
| 48 | } |
| 49 | return st.Mode() |
| 50 | } |
| 51 | |
| 52 | // journal-migrate runs from the window's umask 077 root shell. Both public |
| 53 | // floor directories come out 0755, whether they are missing, left 0700 by |
| 54 | // an earlier attempt, or left by an earlier build's interrupted |
| 55 | // mkdirAllExact (mkdir done under the umask, chmod never reached). |
| 56 | func TestRootFloorDirsIgnoreUmask(t *testing.T) { |
| 57 | old := syscall.Umask(0o077) |
| 58 | defer syscall.Umask(old) |
| 59 | uid, gid := uint32(os.Getuid()), uint32(os.Getgid()) |
| 60 | for name, earlier := range map[string]func(opt string) error{ |
| 61 | "missing": func(string) error { return nil }, |
| 62 | "moves 0700": func(opt string) error { return os.Mkdir(rootFloorDir(opt), 0o700) }, |
| 63 | "seeds 0700": func(opt string) error { return os.Mkdir(rootSeedsFloorDir(opt), 0o700) }, |
| 64 | "interrupted": func(opt string) error { return os.MkdirAll(rootSeedsFloorDir(opt), 0o755) }, // an earlier build's mkdirAllExact mkdir, under 077 |
| 65 | "both 0700": func(opt string) error { |
| 66 | return errors.Join(os.Mkdir(rootFloorDir(opt), 0o700), os.Mkdir(rootSeedsFloorDir(opt), 0o700)) |
| 67 | }, |
| 68 | } { |
| 69 | t.Run(name, func(t *testing.T) { |
| 70 | opt := floorDirsOpt(t) |
| 71 | if err := earlier(opt); err != nil { |
| 72 | t.Fatal(err) |
| 73 | } |
| 74 | if err := prepareRootFloorDirsOwned(opt, opt, uid, gid); err != nil { |
| 75 | t.Fatal(err) |
| 76 | } |
| 77 | for _, dir := range []string{rootFloorDir(opt), rootSeedsFloorDir(opt), systemGuardDir(opt)} { |
| 78 | if m := floorDirMode(t, dir); !m.IsDir() || m.Perm() != 0o755 { |
| 79 | t.Fatalf("%s is %v, want a 0755 directory", dir, m) |
| 80 | } |
| 81 | } |
| 82 | }) |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | // The repair touches only a real directory with the expected owner: a |
| 87 | // symlink (at the directory or on its way), a file, or another owner is |
| 88 | // refused and left as it was. |
| 89 | func TestRootFloorDirsRefuseWhatTheyDoNotOwn(t *testing.T) { |
| 90 | uid, gid := uint32(os.Getuid()), uint32(os.Getgid()) |
| 91 | for name, c := range map[string]struct { |
| 92 | setup func(t *testing.T, opt string) string // returns the path whose mode must not change |
| 93 | uid, gid uint32 |
| 94 | want []error // the refusal is one of these, so it is this case's own |
| 95 | }{ |
| 96 | "symlink": {setup: func(t *testing.T, opt string) string { |
| 97 | target := filepath.Join(opt, "elsewhere") |
| 98 | if err := os.Mkdir(target, 0o700); err != nil { |
| 99 | t.Fatal(err) |
| 100 | } |
| 101 | if err := os.Symlink(target, rootFloorDir(opt)); err != nil { |
| 102 | t.Fatal(err) |
| 103 | } |
| 104 | return target |
| 105 | }, uid: uid, gid: gid, want: []error{unix.ELOOP, unix.ENOTDIR}}, |
| 106 | "symlink on the way": {setup: func(t *testing.T, opt string) string { |
| 107 | real := filepath.Join(opt, "realguard") |
| 108 | if err := os.Rename(systemGuardDir(opt), real); err != nil { |
| 109 | t.Fatal(err) |
| 110 | } |
| 111 | if err := os.Mkdir(filepath.Join(real, "moves"), 0o700); err != nil { |
| 112 | t.Fatal(err) |
| 113 | } |
| 114 | if err := os.Symlink(real, systemGuardDir(opt)); err != nil { |
| 115 | t.Fatal(err) |
| 116 | } |
| 117 | return filepath.Join(real, "moves") |
| 118 | }, uid: uid, gid: gid, want: []error{unix.ELOOP, unix.ENOTDIR}}, |
| 119 | "file": {setup: func(t *testing.T, opt string) string { |
| 120 | if err := os.WriteFile(rootFloorDir(opt), nil, 0o600); err != nil { |
| 121 | t.Fatal(err) |
| 122 | } |
| 123 | return rootFloorDir(opt) |
| 124 | }, uid: uid, gid: gid, want: []error{unix.ENOTDIR}}, |
| 125 | // Unprivileged, every directory here is the test's, so another |
| 126 | // owner refuses at the base, before the leaf; the leaf's own owner |
| 127 | // check is the root runner's (the Foreign rerun witness). |
| 128 | "other owner": {setup: func(t *testing.T, opt string) string { |
| 129 | if err := os.Mkdir(rootFloorDir(opt), 0o700); err != nil { |
| 130 | t.Fatal(err) |
| 131 | } |
| 132 | return rootFloorDir(opt) |
| 133 | }, uid: uid + 1, gid: gid, want: []error{os.ErrPermission}}, |
| 134 | "other group": {setup: func(t *testing.T, opt string) string { |
| 135 | if err := os.Mkdir(rootFloorDir(opt), 0o700); err != nil { |
| 136 | t.Fatal(err) |
| 137 | } |
| 138 | return rootFloorDir(opt) |
| 139 | }, uid: uid, gid: gid + 1, want: []error{os.ErrPermission}}, |
| 140 | } { |
| 141 | t.Run(name, func(t *testing.T) { |
| 142 | opt := floorDirsOpt(t) |
| 143 | left := c.setup(t, opt) |
| 144 | before := floorDirMode(t, left) |
| 145 | err := prepareRootFloorDirsOwned(opt, opt, c.uid, c.gid) |
| 146 | if !slices.ContainsFunc(c.want, func(w error) bool { return errors.Is(err, w) }) { |
| 147 | t.Fatalf("repair = %v, want a refusal with one of %v", err, c.want) |
| 148 | } |
| 149 | if after := floorDirMode(t, left); after != before { |
| 150 | t.Fatalf("%s changed from %v to %v", left, before, after) |
| 151 | } |
| 152 | }) |
| 153 | } |
| 154 | // Production's owner is root: unprivileged, the test's own directories |
| 155 | // are another owner's, so prepareRootFloorDirs refuses them untouched. |
| 156 | if os.Geteuid() != 0 { |
| 157 | opt := floorDirsOpt(t) |
| 158 | if err := os.Mkdir(rootFloorDir(opt), 0o700); err != nil { |
| 159 | t.Fatal(err) |
| 160 | } |
| 161 | if err := prepareRootFloorDirs(opt); !errors.Is(err, os.ErrPermission) { |
| 162 | t.Fatalf("prepareRootFloorDirs over a non-root directory = %v", err) |
| 163 | } |
| 164 | if m := floorDirMode(t, rootFloorDir(opt)); m.Perm() != 0o700 { |
| 165 | t.Fatalf("refused directory is now %v", m) |
| 166 | } |
| 167 | } |
| 168 | } |
| 169 | |
| 170 | // floorTree records every path under roots, with its mode, owner and, for |
| 171 | // a symlink, its target, so a refusal can be shown to have changed nothing. |
| 172 | func floorTree(t *testing.T, roots ...string) map[string]string { |
| 173 | t.Helper() |
| 174 | out := map[string]string{} |
| 175 | for _, root := range roots { |
| 176 | err := filepath.WalkDir(root, func(path string, _ fs.DirEntry, err error) error { |
| 177 | if err != nil { |
| 178 | return err |
| 179 | } |
| 180 | st, err := os.Lstat(path) |
| 181 | if err != nil { |
| 182 | return err |
| 183 | } |
| 184 | sys := st.Sys().(*syscall.Stat_t) |
| 185 | v := fmt.Sprintf("%v %d:%d", st.Mode(), sys.Uid, sys.Gid) |
| 186 | if st.Mode()&os.ModeSymlink != 0 { |
| 187 | target, err := os.Readlink(path) |
| 188 | if err != nil { |
| 189 | return err |
| 190 | } |
| 191 | v += " -> " + target |
| 192 | } |
| 193 | out[path] = v |
| 194 | return nil |
| 195 | }) |
| 196 | if err != nil { |
| 197 | t.Fatal(err) |
| 198 | } |
| 199 | } |
| 200 | return out |
| 201 | } |
| 202 | |
| 203 | // Fix round 2: the repair checks every directory from its base to the |
| 204 | // floor directory's parent before it makes or changes anything. A symlink |
| 205 | // or a missing directory on the way, an ancestor writable by group or |
| 206 | // others, or one with another owner refuses, whether the floor directory |
| 207 | // is missing (nothing is made, in either tree) or left 0700 (it stays so). |
| 208 | func TestRootFloorDirsCheckAncestryFirst(t *testing.T) { |
| 209 | uid, gid := uint32(os.Getuid()), uint32(os.Getgid()) |
| 210 | elsewhere := func(t *testing.T) string { |
| 211 | t.Helper() |
| 212 | dir, err := filepath.EvalSymlinks(t.TempDir()) |
| 213 | if err != nil { |
| 214 | t.Fatal(err) |
| 215 | } |
| 216 | return dir |
| 217 | } |
| 218 | moves0700 := func(t *testing.T, opt string) { |
| 219 | t.Helper() |
| 220 | if err := os.Mkdir(rootFloorDir(opt), 0o700); err != nil { |
| 221 | t.Fatal(err) |
| 222 | } |
| 223 | } |
| 224 | for name, c := range map[string]struct { |
| 225 | // setup returns any tree outside opt that must not change either. |
| 226 | setup func(t *testing.T, opt string) []string |
| 227 | uid, gid uint32 |
| 228 | want []error // the refusal is one of these, so it is this case's own |
| 229 | }{ |
| 230 | "symlinked guard, moves missing": {setup: func(t *testing.T, opt string) []string { |
| 231 | target := elsewhere(t) |
| 232 | if err := os.Remove(systemGuardDir(opt)); err != nil { |
| 233 | t.Fatal(err) |
| 234 | } |
| 235 | if err := os.Symlink(target, systemGuardDir(opt)); err != nil { |
| 236 | t.Fatal(err) |
| 237 | } |
| 238 | return []string{target} |
| 239 | }, uid: uid, gid: gid, want: []error{unix.ELOOP, unix.ENOTDIR}}, |
| 240 | "symlinked system, moves missing": {setup: func(t *testing.T, opt string) []string { |
| 241 | target := elsewhere(t) |
| 242 | if err := os.Mkdir(filepath.Join(target, "guard"), 0o755); err != nil { |
| 243 | t.Fatal(err) |
| 244 | } |
| 245 | if err := os.RemoveAll(filepath.Join(opt, "system")); err != nil { |
| 246 | t.Fatal(err) |
| 247 | } |
| 248 | if err := os.Symlink(target, filepath.Join(opt, "system")); err != nil { |
| 249 | t.Fatal(err) |
| 250 | } |
| 251 | return []string{target} |
| 252 | }, uid: uid, gid: gid, want: []error{unix.ELOOP, unix.ENOTDIR}}, |
| 253 | "guard missing": {setup: func(t *testing.T, opt string) []string { |
| 254 | if err := os.Remove(systemGuardDir(opt)); err != nil { |
| 255 | t.Fatal(err) |
| 256 | } |
| 257 | return nil |
| 258 | }, uid: uid, gid: gid, want: []error{unix.ENOENT}}, |
| 259 | "group-writable system, moves 0700": {setup: func(t *testing.T, opt string) []string { |
| 260 | moves0700(t, opt) |
| 261 | if err := os.Chmod(filepath.Join(opt, "system"), 0o775); err != nil { |
| 262 | t.Fatal(err) |
| 263 | } |
| 264 | return nil |
| 265 | }, uid: uid, gid: gid, want: []error{os.ErrPermission}}, |
| 266 | "world-writable guard, moves missing": {setup: func(t *testing.T, opt string) []string { |
| 267 | if err := os.Chmod(systemGuardDir(opt), 0o777); err != nil { |
| 268 | t.Fatal(err) |
| 269 | } |
| 270 | return nil |
| 271 | }, uid: uid, gid: gid, want: []error{os.ErrPermission}}, |
| 272 | "world-writable base, moves 0700": {setup: func(t *testing.T, opt string) []string { |
| 273 | moves0700(t, opt) |
| 274 | if err := os.Chmod(opt, 0o757); err != nil { |
| 275 | t.Fatal(err) |
| 276 | } |
| 277 | return nil |
| 278 | }, uid: uid, gid: gid, want: []error{os.ErrPermission}}, |
| 279 | // Every ancestor is another owner's; the floor directory would be |
| 280 | // made by the test's own uid, so a create before the ancestry check |
| 281 | // shows in the tree. |
| 282 | "other-owned ancestors, moves missing": {setup: func(t *testing.T, opt string) []string { |
| 283 | return nil |
| 284 | }, uid: uid + 1, gid: gid, want: []error{os.ErrPermission}}, |
| 285 | } { |
| 286 | t.Run(name, func(t *testing.T) { |
| 287 | opt := floorDirsOpt(t) |
| 288 | others := c.setup(t, opt) |
| 289 | roots := append([]string{opt}, others...) |
| 290 | before := floorTree(t, roots...) |
| 291 | err := prepareRootFloorDirsOwned(opt, opt, c.uid, c.gid) |
| 292 | if err == nil { |
| 293 | t.Fatal("repair accepted it") |
| 294 | } |
| 295 | if !slices.ContainsFunc(c.want, func(w error) bool { return errors.Is(err, w) }) { |
| 296 | t.Fatalf("refused with %v, want one of %v", err, c.want) |
| 297 | } |
| 298 | if after := floorTree(t, roots...); !maps.Equal(before, after) { |
| 299 | t.Fatalf("the refused repair changed the tree:\nbefore %v\nafter %v", before, after) |
| 300 | } |
| 301 | for _, root := range others { |
| 302 | if _, err := os.Lstat(filepath.Join(root, "moves")); !errors.Is(err, os.ErrNotExist) { |
| 303 | t.Fatal("moves made through the symlink", err) |
| 304 | } |
| 305 | } |
| 306 | }) |
| 307 | } |
| 308 | // The repair's own argument checks: a floor directory not beneath the |
| 309 | // base, or the base itself, refuses before any open. |
| 310 | opt := floorDirsOpt(t) |
| 311 | for _, base := range []string{rootFloorDir(opt), filepath.Join(opt, "elsewhere"), "relative"} { |
| 312 | if err := repairRootFloorDir(base, rootFloorDir(opt), uid, gid); !errors.Is(err, os.ErrPermission) { |
| 313 | t.Fatalf("base %s: %v", base, err) |
| 314 | } |
| 315 | } |
| 316 | if _, err := os.Lstat(rootFloorDir(opt)); !errors.Is(err, os.ErrNotExist) { |
| 317 | t.Fatal("moves made", err) |
| 318 | } |
| 319 | } |
| 320 | |
| 321 | // The migration repairs the floor directories under its lock and quiesce, |
| 322 | // before guardReady's first floor read; a refused repair stops it there, |
| 323 | // with no census and no record written. |
| 324 | func TestRootMigrationPreparesFloorsBeforeGuardReady(t *testing.T) { |
| 325 | m, _, _ := migrationFixture(t) |
| 326 | var order []string |
| 327 | quiesce := m.quiesce |
| 328 | m.quiesce = func(ctx context.Context) (func(), error) { order = append(order, "quiesce"); return quiesce(ctx) } |
| 329 | m.prepareFloors = func(context.Context) error { order = append(order, "prepareFloors"); return nil } |
| 330 | m.guardReady = func(context.Context) error { order = append(order, "guardReady"); return nil } |
| 331 | observe := m.observe |
| 332 | m.observe = func(ctx context.Context) (rootMigrationSnapshot, error) { |
| 333 | order = append(order, "observe") |
| 334 | return observe(ctx) |
| 335 | } |
| 336 | if err := m.run(t.Context()); err != nil { |
| 337 | t.Fatal(err) |
| 338 | } |
| 339 | if len(order) < 4 || !slices.Equal(order[:4], []string{"quiesce", "prepareFloors", "guardReady", "observe"}) { |
| 340 | t.Fatalf("order = %v", order) |
| 341 | } |
| 342 | |
| 343 | m, _, _ = migrationFixture(t) |
| 344 | guarded := false |
| 345 | m.prepareFloors = func(context.Context) error { return os.ErrPermission } |
| 346 | m.guardReady = func(context.Context) error { guarded = true; return nil } |
| 347 | if err := m.run(t.Context()); !errors.Is(err, os.ErrPermission) || guarded { |
| 348 | t.Fatalf("refused repair: run = %v, guardReady ran = %v", err, guarded) |
| 349 | } |
| 350 | if _, err := m.execution.Read("census.json"); !os.IsNotExist(err) { |
| 351 | t.Fatal("census before the floor repair", err) |
| 352 | } |
| 353 | if _, err := m.state.Read("migration.json"); !os.IsNotExist(err) { |
| 354 | t.Fatal("migration record before the floor repair", err) |
| 355 | } |
| 356 | |
| 357 | m, _, _ = migrationFixture(t) |
| 358 | m.prepareFloors = nil |
| 359 | if err := m.run(t.Context()); !errors.Is(err, errRootMigrationBusy) { |
| 360 | t.Fatalf("no floor repair wired: run = %v", err) |
| 361 | } |
| 362 | } |
| 363 | |
amadan