| 1 | //go:build linux |
| 2 | |
| 3 | package operator |
| 4 | |
| 5 | import ( |
| 6 | "context" |
| 7 | "crypto/sha256" |
| 8 | "database/sql" |
| 9 | "database/sql/driver" |
| 10 | "encoding/hex" |
| 11 | "io" |
| 12 | "net/url" |
| 13 | "os" |
| 14 | "sync" |
| 15 | "time" |
| 16 | |
| 17 | "golang.org/x/sys/unix" |
| 18 | "modernc.org/sqlite" |
| 19 | ) |
| 20 | |
| 21 | // ReadonlyExpectation is an observation required by the unmounted checker. |
| 22 | // It is not launch authority. Verify must check the independently enrolled and |
| 23 | // platform-verified handoff; deriving expectations from this database is invalid. |
| 24 | type ReadonlyExpectation struct { |
| 25 | Path string |
| 26 | Device, Inode uint64 |
| 27 | Length int64 |
| 28 | SHA256 string |
| 29 | } |
| 30 | |
| 31 | // InspectReadonly runs only in the dedicated non-serving checker process, after |
| 32 | // its launch descriptors are closed. Verify owns launch/enrollment verification; |
| 33 | // no production implementation exists yet. The callback must not open files, |
| 34 | // start goroutines, retain the connection, or perform network or serving work. |
| 35 | // Success is withheld until driver closure and the final exact byte comparison. |
| 36 | func InspectReadonly(ctx context.Context, expected ReadonlyExpectation, verify func(context.Context, ReadonlyExpectation) error, inspect func(context.Context, *sql.Conn) error) error { |
| 37 | return inspectReadonly(ctx, expected, verify, inspect, nil) |
| 38 | } |
| 39 | |
| 40 | func inspectReadonly(ctx context.Context, expected ReadonlyExpectation, verify func(context.Context, ReadonlyExpectation) error, inspect func(context.Context, *sql.Conn) error, hook func(string)) (err error) { |
| 41 | deadline, bounded := ctx.Deadline() |
| 42 | if !bounded || !deadline.After(time.Now()) || verify == nil || inspect == nil || expected.Length <= 0 || expected.Length > 256<<20 || len(expected.SHA256) != 64 { |
| 43 | return ErrRefused |
| 44 | } |
| 45 | hash, e := hex.DecodeString(expected.SHA256) |
| 46 | if e != nil || hex.EncodeToString(hash) != expected.SHA256 || expected.Device == 0 || expected.Inode == 0 { |
| 47 | return ErrRefused |
| 48 | } |
| 49 | ctx, cancel := context.WithTimeout(ctx, 30*time.Second) |
| 50 | defer cancel() |
| 51 | deadline, _ = ctx.Deadline() |
| 52 | if verify(ctx, expected) != nil { |
| 53 | return ErrRefused |
| 54 | } |
| 55 | pin, id, e := pinExisting(expected.Path) |
| 56 | if e != nil { |
| 57 | return e |
| 58 | } |
| 59 | defer func() { |
| 60 | if pin.Close() != nil { |
| 61 | err = ErrUnavailable |
| 62 | } |
| 63 | }() |
| 64 | if id != (fileIdentity{expected.Device, expected.Inode}) { |
| 65 | return ErrRefused |
| 66 | } |
| 67 | c := &readonlyConnector{path: expected.Path, pin: pin, identity: id, deadline: deadline, sqlite: &sqlite.Driver{}, hook: hook} |
| 68 | if c.pathMatches() != nil || hashReadonly(ctx, pin, expected) != nil { |
| 69 | return ErrRefused |
| 70 | } |
| 71 | d := sql.OpenDB(c) |
| 72 | d.SetMaxOpenConns(1) |
| 73 | d.SetMaxIdleConns(1) |
| 74 | defer func() { |
| 75 | if d.Close() != nil { |
| 76 | err = ErrUnavailable |
| 77 | } |
| 78 | }() |
| 79 | conn, e := d.Conn(ctx) |
| 80 | if e != nil { |
| 81 | return ErrUnavailable |
| 82 | } |
| 83 | defer conn.Close() |
| 84 | if _, e = conn.ExecContext(ctx, "PRAGMA query_only=ON"); e != nil { |
| 85 | return ErrUnavailable |
| 86 | } |
| 87 | if _, e = conn.ExecContext(ctx, "PRAGMA temp_store=MEMORY"); e != nil { |
| 88 | return ErrUnavailable |
| 89 | } |
| 90 | var temp int |
| 91 | if conn.QueryRowContext(ctx, "PRAGMA temp_store").Scan(&temp) != nil || temp != 2 { |
| 92 | return ErrRefused |
| 93 | } |
| 94 | if _, e = conn.ExecContext(ctx, "BEGIN"); e != nil { |
| 95 | return ErrUnavailable |
| 96 | } |
| 97 | e = inspect(ctx, conn) |
| 98 | if _, end := conn.ExecContext(ctx, "ROLLBACK"); end != nil { |
| 99 | return ErrUnavailable |
| 100 | } |
| 101 | if e != nil { |
| 102 | if e == ErrUnavailable { |
| 103 | return ErrUnavailable |
| 104 | } |
| 105 | return ErrRefused |
| 106 | } |
| 107 | if conn.Close() != nil || d.Close() != nil { |
| 108 | return ErrUnavailable |
| 109 | } |
| 110 | if c.pathMatches() != nil || hashReadonly(ctx, pin, expected) != nil || verify(ctx, expected) != nil { |
| 111 | return ErrRefused |
| 112 | } |
| 113 | return nil |
| 114 | } |
| 115 | |
| 116 | func hashReadonly(ctx context.Context, pin *os.File, expected ReadonlyExpectation) error { |
| 117 | info, e := pin.Stat() |
| 118 | if e != nil || info.Size() != expected.Length { |
| 119 | return ErrRefused |
| 120 | } |
| 121 | h := sha256.New() |
| 122 | buf := make([]byte, 64<<10) |
| 123 | for off := int64(0); off < expected.Length; { |
| 124 | if ctx.Err() != nil { |
| 125 | return ErrUnavailable |
| 126 | } |
| 127 | size := int64(len(buf)) |
| 128 | if expected.Length-off < size { |
| 129 | size = expected.Length - off |
| 130 | } |
| 131 | n, e := pin.ReadAt(buf[:size], off) |
| 132 | if e != nil || n != int(size) { |
| 133 | return ErrUnavailable |
| 134 | } |
| 135 | h.Write(buf[:n]) |
| 136 | off += int64(n) |
| 137 | } |
| 138 | if hex.EncodeToString(h.Sum(nil)) != expected.SHA256 { |
| 139 | return ErrRefused |
| 140 | } |
| 141 | info, e = pin.Stat() |
| 142 | if e != nil || info.Size() != expected.Length { |
| 143 | return ErrRefused |
| 144 | } |
| 145 | return nil |
| 146 | } |
| 147 | |
| 148 | type readonlyConnector struct { |
| 149 | mu sync.Mutex |
| 150 | path string |
| 151 | pin *os.File |
| 152 | identity fileIdentity |
| 153 | deadline time.Time |
| 154 | sqlite *sqlite.Driver |
| 155 | active bool |
| 156 | hook func(string) |
| 157 | } |
| 158 | type readonlyConnection struct { |
| 159 | driver.Conn |
| 160 | owner *readonlyConnector |
| 161 | mainFD int |
| 162 | baseline map[int]descriptor |
| 163 | closed bool |
| 164 | } |
| 165 | |
| 166 | func (c *readonlyConnector) Driver() driver.Driver { return c.sqlite } |
| 167 | func (c *readonlyConnector) checkpoint(stage string) { |
| 168 | if c.hook != nil { |
| 169 | c.hook(stage) |
| 170 | } |
| 171 | } |
| 172 | func (c *readonlyConnector) pathMatches() error { |
| 173 | if !time.Now().Before(c.deadline) { |
| 174 | return ErrRefused |
| 175 | } |
| 176 | var s unix.Stat_t |
| 177 | if unix.Fstat(int(c.pin.Fd()), &s) != nil || (fileIdentity{uint64(s.Dev), s.Ino}) != c.identity || s.Nlink != 1 { |
| 178 | return ErrRefused |
| 179 | } |
| 180 | id, e := statExisting(c.path) |
| 181 | if e != nil || id != c.identity { |
| 182 | return ErrRefused |
| 183 | } |
| 184 | for _, suffix := range []string{"-wal", "-shm", "-journal"} { |
| 185 | _, e := os.Lstat(c.path + suffix) |
| 186 | if !os.IsNotExist(e) { |
| 187 | return ErrRefused |
| 188 | } |
| 189 | } |
| 190 | return nil |
| 191 | } |
| 192 | func (c *readonlyConnector) Connect(ctx context.Context) (driver.Conn, error) { |
| 193 | c.mu.Lock() |
| 194 | defer c.mu.Unlock() |
| 195 | if c.active || ctx.Err() != nil || c.pathMatches() != nil { |
| 196 | return nil, ErrRefused |
| 197 | } |
| 198 | baseline, e := descriptors() |
| 199 | if e != nil { |
| 200 | return nil, e |
| 201 | } |
| 202 | for _, d := range baseline { |
| 203 | if writable(d.flags) { |
| 204 | return nil, ErrRefused |
| 205 | } |
| 206 | } |
| 207 | c.checkpoint("before-driver") |
| 208 | u := url.URL{Scheme: "file", Path: c.path} |
| 209 | q := u.Query() |
| 210 | q.Set("mode", "ro") |
| 211 | q.Set("immutable", "1") |
| 212 | u.RawQuery = q.Encode() |
| 213 | native, e := c.sqlite.Open(u.String()) |
| 214 | if e != nil { |
| 215 | return nil, ErrUnavailable |
| 216 | } |
| 217 | keep := false |
| 218 | defer func() { |
| 219 | if !keep { |
| 220 | native.Close() |
| 221 | } |
| 222 | }() |
| 223 | c.checkpoint("after-open") |
| 224 | all, e := descriptors() |
| 225 | if e != nil { |
| 226 | return nil, e |
| 227 | } |
| 228 | main := -1 |
| 229 | for fd, d := range all { |
| 230 | if old, ok := baseline[fd]; ok { |
| 231 | if old != d { |
| 232 | return nil, ErrRefused |
| 233 | } |
| 234 | continue |
| 235 | } |
| 236 | if d.identity != c.identity || d.flags&unix.O_ACCMODE != unix.O_RDONLY || d.links != 1 || main != -1 { |
| 237 | return nil, ErrRefused |
| 238 | } |
| 239 | main = fd |
| 240 | } |
| 241 | if main < 0 { |
| 242 | return nil, ErrRefused |
| 243 | } |
| 244 | bound := &readonlyConnection{Conn: native, owner: c, mainFD: main, baseline: baseline} |
| 245 | if bound.check() != nil { |
| 246 | return nil, ErrRefused |
| 247 | } |
| 248 | query, ok := native.(driver.QueryerContext) |
| 249 | if !ok { |
| 250 | return nil, ErrRefused |
| 251 | } |
| 252 | rows, e := query.QueryContext(ctx, "PRAGMA database_list", nil) |
| 253 | if e != nil { |
| 254 | return nil, ErrUnavailable |
| 255 | } |
| 256 | values := make([]driver.Value, 3) |
| 257 | if rows.Next(values) != nil || values[1] != "main" || values[2] != c.path { |
| 258 | rows.Close() |
| 259 | return nil, ErrRefused |
| 260 | } |
| 261 | if rows.Next(values) != io.EOF { |
| 262 | rows.Close() |
| 263 | return nil, ErrRefused |
| 264 | } |
| 265 | if rows.Close() != nil || bound.check() != nil { |
| 266 | return nil, ErrUnavailable |
| 267 | } |
| 268 | c.active = true |
| 269 | keep = true |
| 270 | return bound, nil |
| 271 | } |
| 272 | func (c *readonlyConnection) check() error { |
| 273 | if c.closed || c.owner.pathMatches() != nil { |
| 274 | return ErrRefused |
| 275 | } |
| 276 | all, e := descriptors() |
| 277 | if e != nil { |
| 278 | return e |
| 279 | } |
| 280 | if len(all) != len(c.baseline)+1 { |
| 281 | return ErrRefused |
| 282 | } |
| 283 | for fd, old := range c.baseline { |
| 284 | if all[fd] != old { |
| 285 | return ErrRefused |
| 286 | } |
| 287 | } |
| 288 | main, ok := all[c.mainFD] |
| 289 | if !ok || main.identity != c.owner.identity || main.flags&unix.O_ACCMODE != unix.O_RDONLY || main.links != 1 { |
| 290 | return ErrRefused |
| 291 | } |
| 292 | return nil |
| 293 | } |
| 294 | func (c *readonlyConnection) Close() error { |
| 295 | c.owner.mu.Lock() |
| 296 | defer c.owner.mu.Unlock() |
| 297 | if c.closed { |
| 298 | return nil |
| 299 | } |
| 300 | c.closed = true |
| 301 | e := c.Conn.Close() |
| 302 | c.owner.active = false |
| 303 | return e |
| 304 | } |
| 305 | func (c *readonlyConnection) Prepare(string) (driver.Stmt, error) { return nil, ErrRefused } |
| 306 | func (c *readonlyConnection) PrepareContext(context.Context, string) (driver.Stmt, error) { |
| 307 | return nil, ErrRefused |
| 308 | } |
| 309 | func (c *readonlyConnection) Begin() (driver.Tx, error) { |
| 310 | return c.BeginTx(context.Background(), driver.TxOptions{}) |
| 311 | } |
| 312 | func (c *readonlyConnection) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) { |
| 313 | if c.check() != nil { |
| 314 | return nil, ErrRefused |
| 315 | } |
| 316 | x, ok := c.Conn.(driver.ConnBeginTx) |
| 317 | if !ok { |
| 318 | return nil, ErrRefused |
| 319 | } |
| 320 | tx, e := x.BeginTx(ctx, opts) |
| 321 | if e != nil { |
| 322 | return nil, e |
| 323 | } |
| 324 | if c.check() != nil { |
| 325 | tx.Rollback() |
| 326 | return nil, ErrUnavailable |
| 327 | } |
| 328 | return &readonlyTransaction{tx, c}, nil |
| 329 | } |
| 330 | func (c *readonlyConnection) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) { |
| 331 | if query != "ROLLBACK" && c.check() != nil { |
| 332 | return nil, ErrRefused |
| 333 | } |
| 334 | x, ok := c.Conn.(driver.ExecerContext) |
| 335 | if !ok { |
| 336 | return nil, ErrRefused |
| 337 | } |
| 338 | result, e := x.ExecContext(ctx, query, args) |
| 339 | if e != nil { |
| 340 | return nil, e |
| 341 | } |
| 342 | c.owner.checkpoint("after-exec") |
| 343 | if query != "ROLLBACK" && c.check() != nil { |
| 344 | return nil, ErrUnavailable |
| 345 | } |
| 346 | return result, nil |
| 347 | } |
| 348 | func (c *readonlyConnection) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) { |
| 349 | if c.check() != nil { |
| 350 | return nil, ErrRefused |
| 351 | } |
| 352 | x, ok := c.Conn.(driver.QueryerContext) |
| 353 | if !ok { |
| 354 | return nil, ErrRefused |
| 355 | } |
| 356 | rows, e := x.QueryContext(ctx, query, args) |
| 357 | if e != nil { |
| 358 | return nil, e |
| 359 | } |
| 360 | if c.check() != nil { |
| 361 | rows.Close() |
| 362 | return nil, ErrUnavailable |
| 363 | } |
| 364 | return &readonlyRows{rows, c}, nil |
| 365 | } |
| 366 | func (c *readonlyConnection) Ping(ctx context.Context) error { |
| 367 | if c.check() != nil { |
| 368 | return ErrRefused |
| 369 | } |
| 370 | p, ok := c.Conn.(driver.Pinger) |
| 371 | if !ok { |
| 372 | return ErrRefused |
| 373 | } |
| 374 | if e := p.Ping(ctx); e != nil { |
| 375 | return e |
| 376 | } |
| 377 | if c.check() != nil { |
| 378 | return ErrUnavailable |
| 379 | } |
| 380 | return nil |
| 381 | } |
| 382 | func (c *readonlyConnection) ResetSession(ctx context.Context) error { |
| 383 | if c.check() != nil { |
| 384 | return ErrRefused |
| 385 | } |
| 386 | if r, ok := c.Conn.(driver.SessionResetter); ok { |
| 387 | return r.ResetSession(ctx) |
| 388 | } |
| 389 | return nil |
| 390 | } |
| 391 | func (c *readonlyConnection) IsValid() bool { return c.check() == nil } |
| 392 | |
| 393 | type readonlyRows struct { |
| 394 | driver.Rows |
| 395 | c *readonlyConnection |
| 396 | } |
| 397 | |
| 398 | func (r *readonlyRows) Next(values []driver.Value) error { |
| 399 | if r.c.check() != nil { |
| 400 | return ErrRefused |
| 401 | } |
| 402 | e := r.Rows.Next(values) |
| 403 | if e != nil { |
| 404 | return e |
| 405 | } |
| 406 | if r.c.check() != nil { |
| 407 | return ErrUnavailable |
| 408 | } |
| 409 | return nil |
| 410 | } |
| 411 | |
| 412 | type readonlyTransaction struct { |
| 413 | driver.Tx |
| 414 | c *readonlyConnection |
| 415 | } |
| 416 | |
| 417 | func (t *readonlyTransaction) Commit() error { |
| 418 | if t.c.check() != nil { |
| 419 | return ErrRefused |
| 420 | } |
| 421 | e := t.Tx.Commit() |
| 422 | t.c.owner.checkpoint("after-commit") |
| 423 | if e != nil { |
| 424 | return e |
| 425 | } |
| 426 | if t.c.check() != nil { |
| 427 | return ErrUnavailable |
| 428 | } |
| 429 | return nil |
| 430 | } |
| 431 | |
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