1package mox

3import (

4 "bytes"

5 "context"

6 "crypto"

7 "crypto/ed25519"

8 cryptorand "crypto/rand"

9 "crypto/rsa"

10 "crypto/sha256"

11 "crypto/x509"

12 "encoding/pem"

13 "errors"

14 "fmt"

15 "log/slog"

16 "net"

17 "net/url"

18 "os"

19 "path/filepath"

20 "slices"

21 "sort"

22 "strings"

23 "time"

25 "golang.org/x/exp/maps"

27 "github.com/mjl-/adns"

29 "github.com/mjl-/mox/config"

30 "github.com/mjl-/mox/dkim"

31 "github.com/mjl-/mox/dmarc"

32 "github.com/mjl-/mox/dns"

33 "github.com/mjl-/mox/junk"

34 "github.com/mjl-/mox/mlog"

35 "github.com/mjl-/mox/mtasts"

36 "github.com/mjl-/mox/smtp"

37 "github.com/mjl-/mox/spf"

38 "github.com/mjl-/mox/tlsrpt"

39)

41var ErrRequest = errors.New("bad request")

43// TXTStrings returns a TXT record value as one or more quoted strings, each max

44// 100 characters. In case of multiple strings, a multi-line record is returned.

45func TXTStrings(s string) string {

46 if len(s) <= 100 {

47 return `"` + s + `"`

48 }

50 r := "(\n"

51 for len(s) > 0 {

52 n := len(s)

53 if n > 100 {

54 n = 100

55 }

56 if r != "" {

57 r += " "

58 }

59 r += "\t\t\"" + s[:n] + "\"\n"

60 s = s[n:]

61 }

62 r += "\t)"

63 return r

64}

66// MakeDKIMEd25519Key returns a PEM buffer containing an ed25519 key for use

67// with DKIM.

68// selector and domain can be empty. If not, they are used in the note.

69func MakeDKIMEd25519Key(selector, domain dns.Domain) ([]byte, error) {

70 _, privKey, err := ed25519.GenerateKey(cryptorand.Reader)

71 if err != nil {

72 return nil, fmt.Errorf("generating key: %w", err)

73 }

75 pkcs8, err := x509.MarshalPKCS8PrivateKey(privKey)

76 if err != nil {

77 return nil, fmt.Errorf("marshal key: %w", err)

78 }

80 block := &pem.Block{

81 Type: "PRIVATE KEY",

82 Headers: map[string]string{

83 "Note": dkimKeyNote("ed25519", selector, domain),

84 },

85 Bytes: pkcs8,

86 }

87 b := &bytes.Buffer{}

88 if err := pem.Encode(b, block); err != nil {

89 return nil, fmt.Errorf("encoding pem: %w", err)

90 }

91 return b.Bytes(), nil

92}

94func dkimKeyNote(kind string, selector, domain dns.Domain) string {

95 s := kind + " dkim private key"

96 var zero dns.Domain

97 if selector != zero && domain != zero {

98 s += fmt.Sprintf(" for %s._domainkey.%s", selector.ASCII, domain.ASCII)

99 }

100 s += fmt.Sprintf(", generated by mox on %s", time.Now().Format(time.RFC3339))

101 return s

102}

103

104// MakeDKIMRSAKey returns a PEM buffer containing an rsa key for use with

105// DKIM.

106// selector and domain can be empty. If not, they are used in the note.

107func MakeDKIMRSAKey(selector, domain dns.Domain) ([]byte, error) {

108 // 2048 bits seems reasonable in 2022, 1024 is on the low side, larger

109 // keys may not fit in UDP DNS response.

110 privKey, err := rsa.GenerateKey(cryptorand.Reader, 2048)

111 if err != nil {

112 return nil, fmt.Errorf("generating key: %w", err)

113 }

114

115 pkcs8, err := x509.MarshalPKCS8PrivateKey(privKey)

116 if err != nil {

117 return nil, fmt.Errorf("marshal key: %w", err)

118 }

119

120 block := &pem.Block{

121 Type: "PRIVATE KEY",

122 Headers: map[string]string{

123 "Note": dkimKeyNote("rsa-2048", selector, domain),

124 },

125 Bytes: pkcs8,

126 }

127 b := &bytes.Buffer{}

128 if err := pem.Encode(b, block); err != nil {

129 return nil, fmt.Errorf("encoding pem: %w", err)

130 }

131 return b.Bytes(), nil

132}

133

134// MakeAccountConfig returns a new account configuration for an email address.

135func MakeAccountConfig(addr smtp.Address) config.Account {

136 account := config.Account{

137 Domain: addr.Domain.Name(),

138 Destinations: map[string]config.Destination{

139 addr.String(): {},

140 },

141 RejectsMailbox: "Rejects",

142 JunkFilter: &config.JunkFilter{

143 Threshold: 0.95,

144 Params: junk.Params{

145 Onegrams: true,

146 MaxPower: .01,

147 TopWords: 10,

148 IgnoreWords: .1,

149 RareWords: 2,

150 },

151 },

152 }

153 account.AutomaticJunkFlags.Enabled = true

154 account.AutomaticJunkFlags.JunkMailboxRegexp = "^(junk|spam)"

156 account.SubjectPass.Period = 12 * time.Hour

157 return account

158}

159

160func writeFile(log mlog.Log, path string, data []byte) error {

161 os.MkdirAll(filepath.Dir(path), 0770)

162

163 f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0660)

164 if err != nil {

165 return fmt.Errorf("creating file %s: %s", path, err)

166 }

167 defer func() {

168 if f != nil {

169 err := f.Close()

170 log.Check(err, "closing file after error")

171 err = os.Remove(path)

172 log.Check(err, "removing file after error", slog.String("path", path))

173 }

174 }()

175 if _, err := f.Write(data); err != nil {

176 return fmt.Errorf("writing file %s: %s", path, err)

177 }

178 if err := f.Close(); err != nil {

179 return fmt.Errorf("close file: %v", err)

180 }

181 f = nil

182 return nil

183}

184

185// MakeDomainConfig makes a new config for a domain, creating DKIM keys, using

186// accountName for DMARC and TLS reports.

187func MakeDomainConfig(ctx context.Context, domain, hostname dns.Domain, accountName string, withMTASTS bool) (config.Domain, []string, error) {

188 log := pkglog.WithContext(ctx)

189

190 now := time.Now()

191 year := now.Format("2006")

192 timestamp := now.Format("20060102T150405")

193

194 var paths []string

195 defer func() {

196 for _, p := range paths {

197 err := os.Remove(p)

198 log.Check(err, "removing path for domain config", slog.String("path", p))

199 }

200 }()

201

202 confDKIM := config.DKIM{

203 Selectors: map[string]config.Selector{},

204 }

205

206 addSelector := func(kind, name string, privKey []byte) error {

207 record := fmt.Sprintf("%s._domainkey.%s", name, domain.ASCII)

208 keyPath := filepath.Join("dkim", fmt.Sprintf("%s.%s.%s.privatekey.pkcs8.pem", record, timestamp, kind))

209 p := configDirPath(ConfigDynamicPath, keyPath)

210 if err := writeFile(log, p, privKey); err != nil {

211 return err

212 }

213 paths = append(paths, p)

214 confDKIM.Selectors[name] = config.Selector{

215 // Example from RFC has 5 day between signing and expiration. ../rfc/6376:1393

216 // Expiration is not intended as antireplay defense, but it may help. ../rfc/6376:1340

217 // Messages in the wild have been observed with 2 hours and 1 year expiration.

218 Expiration: "72h",

219 PrivateKeyFile: keyPath,

220 }

221 return nil

222 }

223

224 addEd25519 := func(name string) error {

225 key, err := MakeDKIMEd25519Key(dns.Domain{ASCII: name}, domain)

226 if err != nil {

227 return fmt.Errorf("making dkim ed25519 private key: %s", err)

228 }

229 return addSelector("ed25519", name, key)

230 }

231

232 addRSA := func(name string) error {

233 key, err := MakeDKIMRSAKey(dns.Domain{ASCII: name}, domain)

234 if err != nil {

235 return fmt.Errorf("making dkim rsa private key: %s", err)

236 }

237 return addSelector("rsa2048", name, key)

238 }

239

240 if err := addEd25519(year + "a"); err != nil {

241 return config.Domain{}, nil, err

242 }

243 if err := addRSA(year + "b"); err != nil {

244 return config.Domain{}, nil, err

245 }

246 if err := addEd25519(year + "c"); err != nil {

247 return config.Domain{}, nil, err

248 }

249 if err := addRSA(year + "d"); err != nil {

250 return config.Domain{}, nil, err

251 }

252

253 // We sign with the first two. In case they are misused, the switch to the other

254 // keys is easy, just change the config. Operators should make the public key field

255 // of the misused keys empty in the DNS records to disable the misused keys.

256 confDKIM.Sign = []string{year + "a", year + "b"}

257

258 confDomain := config.Domain{

259 ClientSettingsDomain: "mail." + domain.Name(),

260 LocalpartCatchallSeparator: "+",

261 DKIM: confDKIM,

262 DMARC: &config.DMARC{

263 Account: accountName,

264 Localpart: "dmarc-reports",

265 Mailbox: "DMARC",

266 },

267 TLSRPT: &config.TLSRPT{

268 Account: accountName,

269 Localpart: "tls-reports",

270 Mailbox: "TLSRPT",

271 },

272 }

273

274 if withMTASTS {

275 confDomain.MTASTS = &config.MTASTS{

276 PolicyID: time.Now().UTC().Format("20060102T150405"),

277 Mode: mtasts.ModeEnforce,

278 // We start out with 24 hour, and warn in the admin interface that users should

279 // increase it to weeks once the setup works.

280 MaxAge: 24 * time.Hour,

281 MX: []string{hostname.ASCII},

282 }

283 }

284

285 rpaths := paths

286 paths = nil

287

288 return confDomain, rpaths, nil

289}

290

291// DKIMAdd adds a DKIM selector for a domain, generating a key and writing it to disk.

292func DKIMAdd(ctx context.Context, domain, selector dns.Domain, algorithm, hash string, headerRelaxed, bodyRelaxed, seal bool, headers []string, lifetime time.Duration) (rerr error) {

293 log := pkglog.WithContext(ctx)

294 defer func() {

295 if rerr != nil {

296 log.Errorx("adding dkim key", rerr,

297 slog.Any("domain", domain),

298 slog.Any("selector", selector))

299 }

300 }()

301

302 switch hash {

303 case "sha256", "sha1":

304 default:

305 return fmt.Errorf("%w: unknown hash algorithm %q", ErrRequest, hash)

306 }

307

308 var privKey []byte

309 var err error

310 var kind string

311 switch algorithm {

312 case "rsa":

313 privKey, err = MakeDKIMRSAKey(selector, domain)

314 kind = "rsa2048"

315 case "ed25519":

316 privKey, err = MakeDKIMEd25519Key(selector, domain)

317 kind = "ed25519"

318 default:

319 err = fmt.Errorf("unknown algorithm")

320 }

321 if err != nil {

322 return fmt.Errorf("%w: making dkim key: %v", ErrRequest, err)

323 }

324

325 // Only take lock now, we don't want to hold it while generating a key.

326 Conf.dynamicMutex.Lock()

327 defer Conf.dynamicMutex.Unlock()

328

329 c := Conf.Dynamic

330 d, ok := c.Domains[domain.Name()]

331 if !ok {

332 return fmt.Errorf("%w: domain does not exist", ErrRequest)

333 }

334

335 if _, ok := d.DKIM.Selectors[selector.Name()]; ok {

336 return fmt.Errorf("%w: selector already exists for domain", ErrRequest)

337 }

338

339 record := fmt.Sprintf("%s._domainkey.%s", selector.ASCII, domain.ASCII)

340 timestamp := time.Now().Format("20060102T150405")

341 keyPath := filepath.Join("dkim", fmt.Sprintf("%s.%s.%s.privatekey.pkcs8.pem", record, timestamp, kind))

342 p := configDirPath(ConfigDynamicPath, keyPath)

343 if err := writeFile(log, p, privKey); err != nil {

344 return fmt.Errorf("writing key file: %v", err)

345 }

346 removePath := p

347 defer func() {

348 if removePath != "" {

349 err := os.Remove(removePath)

350 log.Check(err, "removing path for dkim key", slog.String("path", removePath))

351 }

352 }()

353

354 nsel := config.Selector{

355 Hash: hash,

356 Canonicalization: config.Canonicalization{

357 HeaderRelaxed: headerRelaxed,

358 BodyRelaxed: bodyRelaxed,

359 },

360 Headers: headers,

361 DontSealHeaders: !seal,

362 Expiration: lifetime.String(),

363 PrivateKeyFile: keyPath,

364 }

365

366 // All good, time to update the config.

367 nd := d

368 nd.DKIM.Selectors = map[string]config.Selector{}

369 for name, osel := range d.DKIM.Selectors {

370 nd.DKIM.Selectors[name] = osel

371 }

372 nd.DKIM.Selectors[selector.Name()] = nsel

373 nc := c

374 nc.Domains = map[string]config.Domain{}

375 for name, dom := range c.Domains {

376 nc.Domains[name] = dom

377 }

378 nc.Domains[domain.Name()] = nd

379

380 if err := writeDynamic(ctx, log, nc); err != nil {

381 return fmt.Errorf("writing domains.conf: %w", err)

382 }

383

384 log.Info("dkim key added", slog.Any("domain", domain), slog.Any("selector", selector))

385 removePath = "" // Prevent cleanup of key file.

386 return nil

387}

388

389// DKIMRemove removes the selector from the domain, moving the key file out of the way.

390func DKIMRemove(ctx context.Context, domain, selector dns.Domain) (rerr error) {

391 log := pkglog.WithContext(ctx)

392 defer func() {

393 if rerr != nil {

394 log.Errorx("removing dkim key", rerr,

395 slog.Any("domain", domain),

396 slog.Any("selector", selector))

397 }

398 }()

399

400 Conf.dynamicMutex.Lock()

401 defer Conf.dynamicMutex.Unlock()

402

403 c := Conf.Dynamic

404 d, ok := c.Domains[domain.Name()]

405 if !ok {

406 return fmt.Errorf("%w: domain does not exist", ErrRequest)

407 }

408

409 sel, ok := d.DKIM.Selectors[selector.Name()]

410 if !ok {

411 return fmt.Errorf("%w: selector does not exist for domain", ErrRequest)

412 }

413

414 nsels := map[string]config.Selector{}

415 for name, sel := range d.DKIM.Selectors {

416 if name != selector.Name() {

417 nsels[name] = sel

418 }

419 }

420 nsign := make([]string, 0, len(d.DKIM.Sign))

421 for _, name := range d.DKIM.Sign {

422 if name != selector.Name() {

423 nsign = append(nsign, name)

424 }

425 }

426

427 nd := d

428 nd.DKIM = config.DKIM{Selectors: nsels, Sign: nsign}

429 nc := c

430 nc.Domains = map[string]config.Domain{}

431 for name, dom := range c.Domains {

432 nc.Domains[name] = dom

433 }

434 nc.Domains[domain.Name()] = nd

435

436 if err := writeDynamic(ctx, log, nc); err != nil {

437 return fmt.Errorf("writing domains.conf: %w", err)

438 }

439

440 // Move away a DKIM private key to a subdirectory "old". But only if

441 // not in use by other domains.

442 usedKeyPaths := gatherUsedKeysPaths(nc)

443 moveAwayKeys(log, map[string]config.Selector{selector.Name(): sel}, usedKeyPaths)

444

445 log.Info("dkim key removed", slog.Any("domain", domain), slog.Any("selector", selector))

446 return nil

447}

448

449// DomainAdd adds the domain to the domains config, rewriting domains.conf and

450// marking it loaded.

451//

452// accountName is used for DMARC/TLS report and potentially for the postmaster address.

453// If the account does not exist, it is created with localpart. Localpart must be

454// set only if the account does not yet exist.

455func DomainAdd(ctx context.Context, domain dns.Domain, accountName string, localpart smtp.Localpart) (rerr error) {

456 log := pkglog.WithContext(ctx)

457 defer func() {

458 if rerr != nil {

459 log.Errorx("adding domain", rerr,

460 slog.Any("domain", domain),

461 slog.String("account", accountName),

462 slog.Any("localpart", localpart))

463 }

464 }()

465

466 Conf.dynamicMutex.Lock()

467 defer Conf.dynamicMutex.Unlock()

468

469 c := Conf.Dynamic

470 if _, ok := c.Domains[domain.Name()]; ok {

471 return fmt.Errorf("%w: domain already present", ErrRequest)

472 }

473

474 // Compose new config without modifying existing data structures. If we fail, we

475 // leave no trace.

476 nc := c

477 nc.Domains = map[string]config.Domain{}

478 for name, d := range c.Domains {

479 nc.Domains[name] = d

480 }

481

482 // Only enable mta-sts for domain if there is a listener with mta-sts.

483 var withMTASTS bool

484 for _, l := range Conf.Static.Listeners {

485 if l.MTASTSHTTPS.Enabled {

486 withMTASTS = true

487 break

488 }

489 }

490

491 confDomain, cleanupFiles, err := MakeDomainConfig(ctx, domain, Conf.Static.HostnameDomain, accountName, withMTASTS)

492 if err != nil {

493 return fmt.Errorf("preparing domain config: %v", err)

494 }

495 defer func() {

496 for _, f := range cleanupFiles {

497 err := os.Remove(f)

498 log.Check(err, "cleaning up file after error", slog.String("path", f))

499 }

500 }()

501

502 if _, ok := c.Accounts[accountName]; ok && localpart != "" {

503 return fmt.Errorf("%w: account already exists (leave localpart empty when using an existing account)", ErrRequest)

504 } else if !ok && localpart == "" {

505 return fmt.Errorf("%w: account does not yet exist (specify a localpart)", ErrRequest)

506 } else if accountName == "" {

507 return fmt.Errorf("%w: account name is empty", ErrRequest)

508 } else if !ok {

509 nc.Accounts[accountName] = MakeAccountConfig(smtp.NewAddress(localpart, domain))

510 } else if accountName != Conf.Static.Postmaster.Account {

511 nacc := nc.Accounts[accountName]

512 nd := map[string]config.Destination{}

513 for k, v := range nacc.Destinations {

514 nd[k] = v

515 }

516 pmaddr := smtp.NewAddress("postmaster", domain)

517 nd[pmaddr.String()] = config.Destination{}

518 nacc.Destinations = nd

519 nc.Accounts[accountName] = nacc

520 }

521

522 nc.Domains[domain.Name()] = confDomain

523

524 if err := writeDynamic(ctx, log, nc); err != nil {

525 return fmt.Errorf("writing domains.conf: %w", err)

526 }

527 log.Info("domain added", slog.Any("domain", domain))

528 cleanupFiles = nil // All good, don't cleanup.

529 return nil

530}

531

532// DomainRemove removes domain from the config, rewriting domains.conf.

533//

534// No accounts are removed, also not when they still reference this domain.

535func DomainRemove(ctx context.Context, domain dns.Domain) (rerr error) {

536 log := pkglog.WithContext(ctx)

537 defer func() {

538 if rerr != nil {

539 log.Errorx("removing domain", rerr, slog.Any("domain", domain))

540 }

541 }()

542

543 Conf.dynamicMutex.Lock()

544 defer Conf.dynamicMutex.Unlock()

545

546 c := Conf.Dynamic

547 domConf, ok := c.Domains[domain.Name()]

548 if !ok {

549 return fmt.Errorf("%w: domain does not exist", ErrRequest)

550 }

551

552 // Compose new config without modifying existing data structures. If we fail, we

553 // leave no trace.

554 nc := c

555 nc.Domains = map[string]config.Domain{}

556 s := domain.Name()

557 for name, d := range c.Domains {

558 if name != s {

559 nc.Domains[name] = d

560 }

561 }

562

563 if err := writeDynamic(ctx, log, nc); err != nil {

564 return fmt.Errorf("writing domains.conf: %w", err)

565 }

566

567 // Move away any DKIM private keys to a subdirectory "old". But only if

568 // they are not in use by other domains.

569 usedKeyPaths := gatherUsedKeysPaths(nc)

570 moveAwayKeys(log, domConf.DKIM.Selectors, usedKeyPaths)

571

572 log.Info("domain removed", slog.Any("domain", domain))

573 return nil

574}

575

576func gatherUsedKeysPaths(nc config.Dynamic) map[string]bool {

577 usedKeyPaths := map[string]bool{}

578 for _, dc := range nc.Domains {

579 for _, sel := range dc.DKIM.Selectors {

580 usedKeyPaths[filepath.Clean(sel.PrivateKeyFile)] = true

581 }

582 }

583 return usedKeyPaths

584}

585

586func moveAwayKeys(log mlog.Log, sels map[string]config.Selector, usedKeyPaths map[string]bool) {

587 for _, sel := range sels {

588 if sel.PrivateKeyFile == "" || usedKeyPaths[filepath.Clean(sel.PrivateKeyFile)] {

589 continue

590 }

591 src := ConfigDirPath(sel.PrivateKeyFile)

592 dst := ConfigDirPath(filepath.Join(filepath.Dir(sel.PrivateKeyFile), "old", filepath.Base(sel.PrivateKeyFile)))

593 _, err := os.Stat(dst)

594 if err == nil {

595 err = fmt.Errorf("destination already exists")

596 } else if os.IsNotExist(err) {

597 os.MkdirAll(filepath.Dir(dst), 0770)

598 err = os.Rename(src, dst)

599 }

600 if err != nil {

601 log.Errorx("renaming dkim private key file for removed domain", err, slog.String("src", src), slog.String("dst", dst))

602 }

603 }

604}

605

606// DomainSave calls xmodify with a shallow copy of the domain config. xmodify

607// can modify the config, but must clone all referencing data it changes.

608// xmodify may employ panic-based error handling. After xmodify returns, the

609// modified config is verified, saved and takes effect.

610func DomainSave(ctx context.Context, domainName string, xmodify func(config *config.Domain) error) (rerr error) {

611 log := pkglog.WithContext(ctx)

612 defer func() {

613 if rerr != nil {

614 log.Errorx("saving domain config", rerr)

615 }

616 }()

617

618 Conf.dynamicMutex.Lock()

619 defer Conf.dynamicMutex.Unlock()

620

621 nc := Conf.Dynamic // Shallow copy.

622 dom, ok := nc.Domains[domainName] // dom is a shallow copy.

623 if !ok {

624 return fmt.Errorf("%w: domain not present", ErrRequest)

625 }

626

627 if err := xmodify(&dom); err != nil {

628 return err

629 }

630

631 // Compose new config without modifying existing data structures. If we fail, we

632 // leave no trace.

633 nc.Domains = map[string]config.Domain{}

634 for name, d := range Conf.Dynamic.Domains {

635 nc.Domains[name] = d

636 }

637 nc.Domains[domainName] = dom

638

639 if err := writeDynamic(ctx, log, nc); err != nil {

640 return fmt.Errorf("writing domains.conf: %w", err)

641 }

642

643 log.Info("domain saved")

644 return nil

645}

646

647// ConfigSave calls xmodify with a shallow copy of the dynamic config. xmodify

648// can modify the config, but must clone all referencing data it changes.

649// xmodify may employ panic-based error handling. After xmodify returns, the

650// modified config is verified, saved and takes effect.

651func ConfigSave(ctx context.Context, xmodify func(config *config.Dynamic)) (rerr error) {

652 log := pkglog.WithContext(ctx)

653 defer func() {

654 if rerr != nil {

655 log.Errorx("saving config", rerr)

656 }

657 }()

658

659 Conf.dynamicMutex.Lock()

660 defer Conf.dynamicMutex.Unlock()

661

662 nc := Conf.Dynamic // Shallow copy.

663 xmodify(&nc)

664

665 if err := writeDynamic(ctx, log, nc); err != nil {

666 return fmt.Errorf("writing domains.conf: %w", err)

667 }

668

669 log.Info("config saved")

670 return nil

671}

672

673// DomainSPFIPs returns IPs to include in SPF records for domains. It includes the

674// IPs on listeners that have SMTP enabled, and includes IPs configured for SOCKS

675// transports.

676func DomainSPFIPs() (ips []net.IP) {

677 for _, l := range Conf.Static.Listeners {

678 if !l.SMTP.Enabled || l.IPsNATed {

679 continue

680 }

681 ipstrs := l.IPs

682 if len(l.NATIPs) > 0 {

683 ipstrs = l.NATIPs

684 }

685 for _, ipstr := range ipstrs {

686 ip := net.ParseIP(ipstr)

687 ips = append(ips, ip)

688 }

689 }

690 for _, t := range Conf.Static.Transports {

691 if t.Socks != nil {

692 ips = append(ips, t.Socks.IPs...)

693 }

694 }

695 return ips

696}

697

698// todo: find a way to automatically create the dns records as it would greatly simplify setting up email for a domain. we could also dynamically make changes, e.g. providing grace periods after disabling a dkim key, only automatically removing the dkim dns key after a few days. but this requires some kind of api and authentication to the dns server. there doesn't appear to be a single commonly used api for dns management. each of the numerous cloud providers have their own APIs and rather large SKDs to use them. we don't want to link all of them in.

699

700// DomainRecords returns text lines describing DNS records required for configuring

701// a domain.

702//

703// If certIssuerDomainName is set, CAA records to limit TLS certificate issuance to

704// that caID will be suggested. If acmeAccountURI is also set, CAA records also

705// restricting issuance to that account ID will be suggested.

706func DomainRecords(domConf config.Domain, domain dns.Domain, hasDNSSEC bool, certIssuerDomainName, acmeAccountURI string) ([]string, error) {

707 d := domain.ASCII

708 h := Conf.Static.HostnameDomain.ASCII

709

710 // The first line with ";" is used by ../testdata/integration/moxacmepebble.sh and

711 // ../testdata/integration/moxmail2.sh for selecting DNS records

712 records := []string{

713 "; Time To Live of 5 minutes, may be recognized if importing as a zone file.",

714 "; Once your setup is working, you may want to increase the TTL.",

715 "$TTL 300",

716 "",

717 }

718

719 if public, ok := Conf.Static.Listeners["public"]; ok && public.TLS != nil && (len(public.TLS.HostPrivateRSA2048Keys) > 0 || len(public.TLS.HostPrivateECDSAP256Keys) > 0) {

720 records = append(records,

721 `; DANE: These records indicate that a remote mail server trying to deliver email`,

722 `; with SMTP (TCP port 25) must verify the TLS certificate with DANE-EE (3), based`,

723 `; on the certificate public key ("SPKI", 1) that is SHA2-256-hashed (1) to the`,

724 `; hexadecimal hash. DANE-EE verification means only the certificate or public`,

725 `; key is verified, not whether the certificate is signed by a (centralized)`,

726 `; certificate authority (CA), is expired, or matches the host name.`,

727 `;`,

728 `; NOTE: Create the records below only once: They are for the machine, and apply`,

729 `; to all hosted domains.`,

730 )

731 if !hasDNSSEC {

732 records = append(records,

733 ";",

734 "; WARNING: Domain does not appear to be DNSSEC-signed. To enable DANE, first",

735 "; enable DNSSEC on your domain, then add the TLSA records. Records below have been",

736 "; commented out.",

737 )

738 }

739 addTLSA := func(privKey crypto.Signer) error {

740 spkiBuf, err := x509.MarshalPKIXPublicKey(privKey.Public())

741 if err != nil {

742 return fmt.Errorf("marshal SubjectPublicKeyInfo for DANE record: %v", err)

743 }

744 sum := sha256.Sum256(spkiBuf)

745 tlsaRecord := adns.TLSA{

746 Usage: adns.TLSAUsageDANEEE,

747 Selector: adns.TLSASelectorSPKI,

748 MatchType: adns.TLSAMatchTypeSHA256,

749 CertAssoc: sum[:],

750 }

751 var s string

752 if hasDNSSEC {

753 s = fmt.Sprintf("_25._tcp.%-*s TLSA %s", 20+len(d)-len("_25._tcp."), h+".", tlsaRecord.Record())

754 } else {

755 s = fmt.Sprintf(";; _25._tcp.%-*s TLSA %s", 20+len(d)-len(";; _25._tcp."), h+".", tlsaRecord.Record())

756 }

757 records = append(records, s)

758 return nil

759 }

760 for _, privKey := range public.TLS.HostPrivateECDSAP256Keys {

761 if err := addTLSA(privKey); err != nil {

762 return nil, err

763 }

764 }

765 for _, privKey := range public.TLS.HostPrivateRSA2048Keys {

766 if err := addTLSA(privKey); err != nil {

767 return nil, err

768 }

769 }

770 records = append(records, "")

771 }

772

773 if d != h {

774 records = append(records,

775 "; For the machine, only needs to be created once, for the first domain added:",

776 "; ",

777 "; SPF-allow host for itself, resulting in relaxed DMARC pass for (postmaster)",

778 "; messages (DSNs) sent from host:",

779 fmt.Sprintf(`%-*s TXT "v=spf1 a -all"`, 20+len(d), h+"."), // ../rfc/7208:2263 ../rfc/7208:2287

780 "",

781 )

782 }

783 if d != h && Conf.Static.HostTLSRPT.ParsedLocalpart != "" {

784 uri := url.URL{

785 Scheme: "mailto",

786 Opaque: smtp.NewAddress(Conf.Static.HostTLSRPT.ParsedLocalpart, Conf.Static.HostnameDomain).Pack(false),

787 }

788 tlsrptr := tlsrpt.Record{Version: "TLSRPTv1", RUAs: [][]tlsrpt.RUA{{tlsrpt.RUA(uri.String())}}}

789 records = append(records,

790 "; For the machine, only needs to be created once, for the first domain added:",

791 "; ",

792 "; Request reporting about success/failures of TLS connections to (MX) host, for DANE.",

793 fmt.Sprintf(`_smtp._tls.%-*s TXT "%s"`, 20+len(d)-len("_smtp._tls."), h+".", tlsrptr.String()),

794 "",

795 )

796 }

797

798 records = append(records,

799 "; Deliver email for the domain to this host.",

800 fmt.Sprintf("%s. MX 10 %s.", d, h),

801 "",

802

803 "; Outgoing messages will be signed with the first two DKIM keys. The other two",

804 "; configured for backup, switching to them is just a config change.",

805 )

806 var selectors []string

807 for name := range domConf.DKIM.Selectors {

808 selectors = append(selectors, name)

809 }

810 sort.Slice(selectors, func(i, j int) bool {

811 return selectors[i] < selectors[j]

812 })

813 for _, name := range selectors {

814 sel := domConf.DKIM.Selectors[name]

815 dkimr := dkim.Record{

816 Version: "DKIM1",

817 Hashes: []string{"sha256"},

818 PublicKey: sel.Key.Public(),

819 }

820 if _, ok := sel.Key.(ed25519.PrivateKey); ok {

821 dkimr.Key = "ed25519"

822 } else if _, ok := sel.Key.(*rsa.PrivateKey); !ok {

823 return nil, fmt.Errorf("unrecognized private key for DKIM selector %q: %T", name, sel.Key)

824 }

825 txt, err := dkimr.Record()

826 if err != nil {

827 return nil, fmt.Errorf("making DKIM DNS TXT record: %v", err)

828 }

829

830 if len(txt) > 100 {

831 records = append(records,

832 "; NOTE: The following is a single long record split over several lines for use",

833 "; in zone files. When adding through a DNS operator web interface, combine the",

834 "; strings into a single string, without ().",

835 )

836 }

837 s := fmt.Sprintf("%s._domainkey.%s. TXT %s", name, d, TXTStrings(txt))

838 records = append(records, s)

839

840 }

841 dmarcr := dmarc.DefaultRecord

842 dmarcr.Policy = "reject"

843 if domConf.DMARC != nil {

844 uri := url.URL{

845 Scheme: "mailto",

846 Opaque: smtp.NewAddress(domConf.DMARC.ParsedLocalpart, domConf.DMARC.DNSDomain).Pack(false),

847 }

848 dmarcr.AggregateReportAddresses = []dmarc.URI{

849 {Address: uri.String(), MaxSize: 10, Unit: "m"},

850 }

851 }

852 dspfr := spf.Record{Version: "spf1"}

853 for _, ip := range DomainSPFIPs() {

854 mech := "ip4"

855 if ip.To4() == nil {

856 mech = "ip6"

857 }

858 dspfr.Directives = append(dspfr.Directives, spf.Directive{Mechanism: mech, IP: ip})

859 }

860 dspfr.Directives = append(dspfr.Directives,

861 spf.Directive{Mechanism: "mx"},

862 spf.Directive{Qualifier: "~", Mechanism: "all"},

863 )

864 dspftxt, err := dspfr.Record()

865 if err != nil {

866 return nil, fmt.Errorf("making domain spf record: %v", err)

867 }

868 records = append(records,

869 "",

870

871 "; Specify the MX host is allowed to send for our domain and for itself (for DSNs).",

872 "; ~all means softfail for anything else, which is done instead of -all to prevent older",

873 "; mail servers from rejecting the message because they never get to looking for a dkim/dmarc pass.",

874 fmt.Sprintf(`%s. TXT "%s"`, d, dspftxt),

875 "",

876

877 "; Emails that fail the DMARC check (without aligned DKIM and without aligned SPF)",

878 "; should be rejected, and request reports. If you email through mailing lists that",

879 "; strip DKIM-Signature headers and don't rewrite the From header, you may want to",

880 "; set the policy to p=none.",

881 fmt.Sprintf(`_dmarc.%s. TXT "%s"`, d, dmarcr.String()),

882 "",

883 )

884

885 if sts := domConf.MTASTS; sts != nil {

886 records = append(records,

887 "; Remote servers can use MTA-STS to verify our TLS certificate with the",

888 "; WebPKI pool of CA's (certificate authorities) when delivering over SMTP with",

889 "; STARTTLSTLS.",

890 fmt.Sprintf(`mta-sts.%s. CNAME %s.`, d, h),

891 fmt.Sprintf(`_mta-sts.%s. TXT "v=STSv1; id=%s"`, d, sts.PolicyID),

892 "",

893 )

894 } else {

895 records = append(records,

896 "; Note: No MTA-STS to indicate TLS should be used. Either because disabled for the",

897 "; domain or because mox.conf does not have a listener with MTA-STS configured.",

898 "",

899 )

900 }

901

902 if domConf.TLSRPT != nil {

903 uri := url.URL{

904 Scheme: "mailto",

905 Opaque: smtp.NewAddress(domConf.TLSRPT.ParsedLocalpart, domConf.TLSRPT.DNSDomain).Pack(false),

906 }

907 tlsrptr := tlsrpt.Record{Version: "TLSRPTv1", RUAs: [][]tlsrpt.RUA{{tlsrpt.RUA(uri.String())}}}

908 records = append(records,

909 "; Request reporting about TLS failures.",

910 fmt.Sprintf(`_smtp._tls.%s. TXT "%s"`, d, tlsrptr.String()),

911 "",

912 )

913 }

914

915 if domConf.ClientSettingsDomain != "" && domConf.ClientSettingsDNSDomain != Conf.Static.HostnameDomain {

916 records = append(records,

917 "; Client settings will reference a subdomain of the hosted domain, making it",

918 "; easier to migrate to a different server in the future by not requiring settings",

919 "; in all clients to be updated.",

920 fmt.Sprintf(`%-*s CNAME %s.`, 20+len(d), domConf.ClientSettingsDNSDomain.ASCII+".", h),

921 "",

922 )

923 }

924

925 records = append(records,

926 "; Autoconfig is used by Thunderbird. Autodiscover is (in theory) used by Microsoft.",

927 fmt.Sprintf(`autoconfig.%s. CNAME %s.`, d, h),

928 fmt.Sprintf(`_autodiscover._tcp.%s. SRV 0 1 443 %s.`, d, h),

929 "",

930

931 // ../rfc/6186:133 ../rfc/8314:692

932 "; For secure IMAP and submission autoconfig, point to mail host.",

933 fmt.Sprintf(`_imaps._tcp.%s. SRV 0 1 993 %s.`, d, h),

934 fmt.Sprintf(`_submissions._tcp.%s. SRV 0 1 465 %s.`, d, h),

935 "",

936 // ../rfc/6186:242

937 "; Next records specify POP3 and non-TLS ports are not to be used.",

938 "; These are optional and safe to leave out (e.g. if you have to click a lot in a",

939 "; DNS admin web interface).",

940 fmt.Sprintf(`_imap._tcp.%s. SRV 0 0 0 .`, d),

941 fmt.Sprintf(`_submission._tcp.%s. SRV 0 0 0 .`, d),

942 fmt.Sprintf(`_pop3._tcp.%s. SRV 0 0 0 .`, d),

943 fmt.Sprintf(`_pop3s._tcp.%s. SRV 0 0 0 .`, d),

944 )

945

946 if certIssuerDomainName != "" {

947 // ../rfc/8659:18 for CAA records.

948 records = append(records,

949 "",

950 "; Optional:",

951 "; You could mark Let's Encrypt as the only Certificate Authority allowed to",

952 "; sign TLS certificates for your domain.",

953 fmt.Sprintf(`%s. CAA 0 issue "%s"`, d, certIssuerDomainName),

954 )

955 if acmeAccountURI != "" {

956 // ../rfc/8657:99 for accounturi.

957 // ../rfc/8657:147 for validationmethods.

958 records = append(records,

959 ";",

960 "; Optionally limit certificates for this domain to the account ID and methods used by mox.",

961 fmt.Sprintf(`;; %s. CAA 0 issue "%s; accounturi=%s; validationmethods=tls-alpn-01,http-01"`, d, certIssuerDomainName, acmeAccountURI),

962 ";",

963 "; Or alternatively only limit for email-specific subdomains, so you can use",

964 "; other accounts/methods for other subdomains.",

965 fmt.Sprintf(`;; autoconfig.%s. CAA 0 issue "%s; accounturi=%s; validationmethods=tls-alpn-01,http-01"`, d, certIssuerDomainName, acmeAccountURI),

966 fmt.Sprintf(`;; mta-sts.%s. CAA 0 issue "%s; accounturi=%s; validationmethods=tls-alpn-01,http-01"`, d, certIssuerDomainName, acmeAccountURI),

967 )

968 if domConf.ClientSettingsDomain != "" && domConf.ClientSettingsDNSDomain != Conf.Static.HostnameDomain {

969 records = append(records,

970 fmt.Sprintf(`;; %-*s CAA 0 issue "%s; accounturi=%s; validationmethods=tls-alpn-01,http-01"`, 20-3+len(d), domConf.ClientSettingsDNSDomain.ASCII, certIssuerDomainName, acmeAccountURI),

971 )

972 }

973 if strings.HasSuffix(h, "."+d) {

974 records = append(records,

975 ";",

976 "; And the mail hostname.",

977 fmt.Sprintf(`;; %-*s CAA 0 issue "%s; accounturi=%s; validationmethods=tls-alpn-01,http-01"`, 20-3+len(d), h+".", certIssuerDomainName, acmeAccountURI),

978 )

979 }

980 } else {

981 // The string "will be suggested" is used by

982 // ../testdata/integration/moxacmepebble.sh and ../testdata/integration/moxmail2.sh

983 // as end of DNS records.

984 records = append(records,

985 ";",

986 "; Note: After starting up, once an ACME account has been created, CAA records",

987 "; that restrict issuance to the account will be suggested.",

988 )

989 }

990 }

991 return records, nil

992}

993

994// AccountAdd adds an account and an initial address and reloads the configuration.

995//

996// The new account does not have a password, so cannot yet log in. Email can be

997// delivered.

998//

999// Catchall addresses are not supported for AccountAdd. Add separately with AddressAdd.

1000func AccountAdd(ctx context.Context, account, address string) (rerr error) {

1001 log := pkglog.WithContext(ctx)

1002 defer func() {

1003 if rerr != nil {

1004 log.Errorx("adding account", rerr, slog.String("account", account), slog.String("address", address))

1005 }

1006 }()

1007

1008 addr, err := smtp.ParseAddress(address)

1009 if err != nil {

1010 return fmt.Errorf("%w: parsing email address: %v", ErrRequest, err)

1011 }

1012

1013 Conf.dynamicMutex.Lock()

1014 defer Conf.dynamicMutex.Unlock()

1015

1016 c := Conf.Dynamic

1017 if _, ok := c.Accounts[account]; ok {

1018 return fmt.Errorf("%w: account already present", ErrRequest)

1019 }

1020

1021 if err := checkAddressAvailable(addr); err != nil {

1022 return fmt.Errorf("%w: address not available: %v", ErrRequest, err)

1023 }

1024

1025 // Compose new config without modifying existing data structures. If we fail, we

1026 // leave no trace.

1027 nc := c

1028 nc.Accounts = map[string]config.Account{}

1029 for name, a := range c.Accounts {

1030 nc.Accounts[name] = a

1031 }

1032 nc.Accounts[account] = MakeAccountConfig(addr)

1033

1034 if err := writeDynamic(ctx, log, nc); err != nil {

1035 return fmt.Errorf("writing domains.conf: %w", err)

1036 }

1037 log.Info("account added", slog.String("account", account), slog.Any("address", addr))

1038 return nil

1039}

1040

1041// AccountRemove removes an account and reloads the configuration.

1042func AccountRemove(ctx context.Context, account string) (rerr error) {

1043 log := pkglog.WithContext(ctx)

1044 defer func() {

1045 if rerr != nil {

1046 log.Errorx("adding account", rerr, slog.String("account", account))

1047 }

1048 }()

1049

1050 Conf.dynamicMutex.Lock()

1051 defer Conf.dynamicMutex.Unlock()

1052

1053 c := Conf.Dynamic

1054 if _, ok := c.Accounts[account]; !ok {

1055 return fmt.Errorf("%w: account does not exist", ErrRequest)

1056 }

1057

1058 // Compose new config without modifying existing data structures. If we fail, we

1059 // leave no trace.

1060 nc := c

1061 nc.Accounts = map[string]config.Account{}

1062 for name, a := range c.Accounts {

1063 if name != account {

1064 nc.Accounts[name] = a

1065 }

1066 }

1067

1068 if err := writeDynamic(ctx, log, nc); err != nil {

1069 return fmt.Errorf("writing domains.conf: %w", err)

1070 }

1071

1072 odir := filepath.Join(DataDirPath("accounts"), account)

1073 tmpdir := filepath.Join(DataDirPath("tmp"), "oldaccount-"+account)

1074 if err := os.Rename(odir, tmpdir); err != nil {

1075 log.Errorx("moving old account data directory out of the way", err, slog.String("account", account))

1076 return fmt.Errorf("account removed, but account data directory %q could not be moved out of the way: %v", odir, err)

1077 }

1078 if err := os.RemoveAll(tmpdir); err != nil {

1079 log.Errorx("removing old account data directory", err, slog.String("account", account))

1080 return fmt.Errorf("account removed, its data directory moved to %q, but removing failed: %v", odir, err)

1081 }

1082

1083 log.Info("account removed", slog.String("account", account))

1084 return nil

1085}

1086

1087// checkAddressAvailable checks that the address after canonicalization is not

1088// already configured, and that its localpart does not contain the catchall

1089// localpart separator.

1090//

1091// Must be called with config lock held.

1092func checkAddressAvailable(addr smtp.Address) error {

1093 dc, ok := Conf.Dynamic.Domains[addr.Domain.Name()]

1094 if !ok {

1095 return fmt.Errorf("domain does not exist")

1096 }

1097 lp := CanonicalLocalpart(addr.Localpart, dc)

1098 if _, ok := Conf.accountDestinations[smtp.NewAddress(lp, addr.Domain).String()]; ok {

1099 return fmt.Errorf("canonicalized address %s already configured", smtp.NewAddress(lp, addr.Domain))

1100 } else if dc.LocalpartCatchallSeparator != "" && strings.Contains(string(addr.Localpart), dc.LocalpartCatchallSeparator) {

1101 return fmt.Errorf("localpart cannot include domain catchall separator %s", dc.LocalpartCatchallSeparator)

1102 } else if _, ok := dc.Aliases[lp.String()]; ok {

1103 return fmt.Errorf("address in use as alias")

1104 }

1105 return nil

1106}

1107

1108// AddressAdd adds an email address to an account and reloads the configuration. If

1109// address starts with an @ it is treated as a catchall address for the domain.

1110func AddressAdd(ctx context.Context, address, account string) (rerr error) {

1111 log := pkglog.WithContext(ctx)

1112 defer func() {

1113 if rerr != nil {

1114 log.Errorx("adding address", rerr, slog.String("address", address), slog.String("account", account))

1115 }

1116 }()

1117

1118 Conf.dynamicMutex.Lock()

1119 defer Conf.dynamicMutex.Unlock()

1120

1121 c := Conf.Dynamic

1122 a, ok := c.Accounts[account]

1123 if !ok {

1124 return fmt.Errorf("%w: account does not exist", ErrRequest)

1125 }

1126

1127 var destAddr string

1128 if strings.HasPrefix(address, "@") {

1129 d, err := dns.ParseDomain(address[1:])

1130 if err != nil {

1131 return fmt.Errorf("%w: parsing domain: %v", ErrRequest, err)

1132 }

1133 dname := d.Name()

1134 destAddr = "@" + dname

1135 if _, ok := Conf.Dynamic.Domains[dname]; !ok {

1136 return fmt.Errorf("%w: domain does not exist", ErrRequest)

1137 } else if _, ok := Conf.accountDestinations[destAddr]; ok {

1138 return fmt.Errorf("%w: catchall address already configured for domain", ErrRequest)

1139 }

1140 } else {

1141 addr, err := smtp.ParseAddress(address)

1142 if err != nil {

1143 return fmt.Errorf("%w: parsing email address: %v", ErrRequest, err)

1144 }

1145

1146 if err := checkAddressAvailable(addr); err != nil {

1147 return fmt.Errorf("%w: address not available: %v", ErrRequest, err)

1148 }

1149 destAddr = addr.String()

1150 }

1151

1152 // Compose new config without modifying existing data structures. If we fail, we

1153 // leave no trace.

1154 nc := c

1155 nc.Accounts = map[string]config.Account{}

1156 for name, a := range c.Accounts {

1157 nc.Accounts[name] = a

1158 }

1159 nd := map[string]config.Destination{}

1160 for name, d := range a.Destinations {

1161 nd[name] = d

1162 }

1163 nd[destAddr] = config.Destination{}

1164 a.Destinations = nd

1165 nc.Accounts[account] = a

1166

1167 if err := writeDynamic(ctx, log, nc); err != nil {

1168 return fmt.Errorf("writing domains.conf: %w", err)

1169 }

1170 log.Info("address added", slog.String("address", address), slog.String("account", account))

1171 return nil

1172}

1173

1174// AddressRemove removes an email address and reloads the configuration.

1175// Address can be a catchall address for the domain of the form "@<domain>".

1176//

1177// If the address is member of an alias, remove it from from the alias, unless it

1178// is the last member.

1179func AddressRemove(ctx context.Context, address string) (rerr error) {

1180 log := pkglog.WithContext(ctx)

1181 defer func() {

1182 if rerr != nil {

1183 log.Errorx("removing address", rerr, slog.String("address", address))

1184 }

1185 }()

1186

1187 Conf.dynamicMutex.Lock()

1188 defer Conf.dynamicMutex.Unlock()

1189

1190 ad, ok := Conf.accountDestinations[address]

1191 if !ok {

1192 return fmt.Errorf("%w: address does not exists", ErrRequest)

1193 }

1194

1195 // Compose new config without modifying existing data structures. If we fail, we

1196 // leave no trace.

1197 a, ok := Conf.Dynamic.Accounts[ad.Account]

1198 if !ok {

1199 return fmt.Errorf("internal error: cannot find account")

1200 }

1201 na := a

1202 na.Destinations = map[string]config.Destination{}

1203 var dropped bool

1204 for destAddr, d := range a.Destinations {

1205 if destAddr != address {

1206 na.Destinations[destAddr] = d

1207 } else {

1208 dropped = true

1209 }

1210 }

1211 if !dropped {

1212 return fmt.Errorf("%w: address not removed, likely a postmaster/reporting address", ErrRequest)

1213 }

1214

1215 // Also remove matching address from FromIDLoginAddresses, composing a new slice.

1216 var fromIDLoginAddresses []string

1217 var dom dns.Domain

1218 var pa smtp.Address // For non-catchall addresses (most).

1219 var err error

1220 if strings.HasPrefix(address, "@") {

1221 dom, err = dns.ParseDomain(address[1:])

1222 if err != nil {

1223 return fmt.Errorf("%w: parsing domain for catchall address: %v", ErrRequest, err)

1224 }

1225 } else {

1226 pa, err = smtp.ParseAddress(address)

1227 if err != nil {

1228 return fmt.Errorf("%w: parsing address: %v", ErrRequest, err)

1229 }

1230 dom = pa.Domain

1231 }

1232 for i, fa := range a.ParsedFromIDLoginAddresses {

1233 if fa.Domain != dom {

1234 // Keep for different domain.

1235 fromIDLoginAddresses = append(fromIDLoginAddresses, a.FromIDLoginAddresses[i])

1236 continue

1237 }

1238 if strings.HasPrefix(address, "@") {

1239 continue

1240 }

1241 dc, ok := Conf.Dynamic.Domains[dom.Name()]

1242 if !ok {

1243 return fmt.Errorf("%w: unknown domain in fromid login address %q", ErrRequest, fa.Pack(true))

1244 }

1245 flp := CanonicalLocalpart(fa.Localpart, dc)

1246 alp := CanonicalLocalpart(pa.Localpart, dc)

1247 if alp != flp {

1248 // Keep for different localpart.

1249 fromIDLoginAddresses = append(fromIDLoginAddresses, a.FromIDLoginAddresses[i])

1250 }

1251 }

1252 na.FromIDLoginAddresses = fromIDLoginAddresses

1253

1254 // And remove as member from aliases configured in domains.

1255 domains := maps.Clone(Conf.Dynamic.Domains)

1256 for _, aa := range na.Aliases {

1257 if aa.SubscriptionAddress != address {

1258 continue

1259 }

1260

1261 aliasAddr := fmt.Sprintf("%s@%s", aa.Alias.LocalpartStr, aa.Alias.Domain.Name())

1262

1263 dom, ok := Conf.Dynamic.Domains[aa.Alias.Domain.Name()]

1264 if !ok {

1265 return fmt.Errorf("cannot find domain for alias %s", aliasAddr)

1266 }

1267 a, ok := dom.Aliases[aa.Alias.LocalpartStr]

1268 if !ok {

1269 return fmt.Errorf("cannot find alias %s", aliasAddr)

1270 }

1271 a.Addresses = slices.Clone(a.Addresses)

1272 a.Addresses = slices.DeleteFunc(a.Addresses, func(v string) bool { return v == address })

1273 if len(a.Addresses) == 0 {

1274 return fmt.Errorf("address is last member of alias %s, add new members or remove alias first", aliasAddr)

1275 }

1276 a.ParsedAddresses = nil // Filled when parsing config.

1277 dom.Aliases = maps.Clone(dom.Aliases)

1278 dom.Aliases[aa.Alias.LocalpartStr] = a

1279 domains[aa.Alias.Domain.Name()] = dom

1280 }

1281 na.Aliases = nil // Filled when parsing config.

1282

1283 nc := Conf.Dynamic

1284 nc.Accounts = map[string]config.Account{}

1285 for name, a := range Conf.Dynamic.Accounts {

1286 nc.Accounts[name] = a

1287 }

1288 nc.Accounts[ad.Account] = na

1289 nc.Domains = domains

1290

1291 if err := writeDynamic(ctx, log, nc); err != nil {

1292 return fmt.Errorf("writing domains.conf: %w", err)

1293 }

1294 log.Info("address removed", slog.String("address", address), slog.String("account", ad.Account))

1295 return nil

1296}

1297

1298func AliasAdd(ctx context.Context, addr smtp.Address, alias config.Alias) error {

1299 return DomainSave(ctx, addr.Domain.Name(), func(d *config.Domain) error {

1300 if _, ok := d.Aliases[addr.Localpart.String()]; ok {

1301 return fmt.Errorf("%w: alias already present", ErrRequest)

1302 }

1303 if d.Aliases == nil {

1304 d.Aliases = map[string]config.Alias{}

1305 }

1306 d.Aliases = maps.Clone(d.Aliases)

1307 d.Aliases[addr.Localpart.String()] = alias

1308 return nil

1309 })

1310}

1311

1312func AliasUpdate(ctx context.Context, addr smtp.Address, alias config.Alias) error {

1313 return DomainSave(ctx, addr.Domain.Name(), func(d *config.Domain) error {

1314 a, ok := d.Aliases[addr.Localpart.String()]

1315 if !ok {

1316 return fmt.Errorf("%w: alias does not exist", ErrRequest)

1317 }

1318 a.PostPublic = alias.PostPublic

1319 a.ListMembers = alias.ListMembers

1320 a.AllowMsgFrom = alias.AllowMsgFrom

1321 d.Aliases = maps.Clone(d.Aliases)

1322 d.Aliases[addr.Localpart.String()] = a

1323 return nil

1324 })

1325}

1326

1327func AliasRemove(ctx context.Context, addr smtp.Address) error {

1328 return DomainSave(ctx, addr.Domain.Name(), func(d *config.Domain) error {

1329 _, ok := d.Aliases[addr.Localpart.String()]

1330 if !ok {

1331 return fmt.Errorf("%w: alias does not exist", ErrRequest)

1332 }

1333 d.Aliases = maps.Clone(d.Aliases)

1334 delete(d.Aliases, addr.Localpart.String())

1335 return nil

1336 })

1337}

1338

1339func AliasAddressesAdd(ctx context.Context, addr smtp.Address, addresses []string) error {

1340 if len(addresses) == 0 {

1341 return fmt.Errorf("%w: at least one address required", ErrRequest)

1342 }

1343 return DomainSave(ctx, addr.Domain.Name(), func(d *config.Domain) error {

1344 alias, ok := d.Aliases[addr.Localpart.String()]

1345 if !ok {

1346 return fmt.Errorf("%w: no such alias", ErrRequest)

1347 }

1348 alias.Addresses = append(slices.Clone(alias.Addresses), addresses...)

1349 alias.ParsedAddresses = nil

1350 d.Aliases = maps.Clone(d.Aliases)

1351 d.Aliases[addr.Localpart.String()] = alias

1352 return nil

1353 })

1354}

1355

1356func AliasAddressesRemove(ctx context.Context, addr smtp.Address, addresses []string) error {

1357 if len(addresses) == 0 {

1358 return fmt.Errorf("%w: need at least one address", ErrRequest)

1359 }

1360 return DomainSave(ctx, addr.Domain.Name(), func(d *config.Domain) error {

1361 alias, ok := d.Aliases[addr.Localpart.String()]

1362 if !ok {

1363 return fmt.Errorf("%w: no such alias", ErrRequest)

1364 }

1365 alias.Addresses = slices.DeleteFunc(slices.Clone(alias.Addresses), func(addr string) bool {

1366 n := len(addresses)

1367 addresses = slices.DeleteFunc(addresses, func(a string) bool { return a == addr })

1368 return n > len(addresses)

1369 })

1370 if len(addresses) > 0 {

1371 return fmt.Errorf("%w: address not found: %s", ErrRequest, strings.Join(addresses, ", "))

1372 }

1373 alias.ParsedAddresses = nil

1374 d.Aliases = maps.Clone(d.Aliases)

1375 d.Aliases[addr.Localpart.String()] = alias

1376 return nil

1377 })

1378}

1379

1380// AccountSave updates the configuration of an account. Function xmodify is called

1381// with a shallow copy of the current configuration of the account. It must not

1382// change referencing fields (e.g. existing slice/map/pointer), they may still be

1383// in use, and the change may be rolled back. Referencing values must be copied and

1384// replaced by the modify. The function may raise a panic for error handling.

1385func AccountSave(ctx context.Context, account string, xmodify func(acc *config.Account)) (rerr error) {

1386 log := pkglog.WithContext(ctx)

1387 defer func() {

1388 if rerr != nil {

1389 log.Errorx("saving account fields", rerr, slog.String("account", account))

1390 }

1391 }()

1392

1393 Conf.dynamicMutex.Lock()

1394 defer Conf.dynamicMutex.Unlock()

1395

1396 c := Conf.Dynamic

1397 acc, ok := c.Accounts[account]

1398 if !ok {

1399 return fmt.Errorf("%w: account not present", ErrRequest)

1400 }

1401

1402 xmodify(&acc)

1403

1404 // Compose new config without modifying existing data structures. If we fail, we

1405 // leave no trace.

1406 nc := c

1407 nc.Accounts = map[string]config.Account{}

1408 for name, a := range c.Accounts {

1409 nc.Accounts[name] = a

1410 }

1411 nc.Accounts[account] = acc

1412

1413 if err := writeDynamic(ctx, log, nc); err != nil {

1414 return fmt.Errorf("writing domains.conf: %w", err)

1415 }

1416 log.Info("account fields saved", slog.String("account", account))

1417 return nil

1418}

1419

1420type TLSMode uint8

1421

1422const (

1423 TLSModeImmediate TLSMode = 0

1424 TLSModeSTARTTLS TLSMode = 1

1425 TLSModeNone TLSMode = 2

1426)

1427

1428type ProtocolConfig struct {

1429 Host dns.Domain

1430 Port int

1431 TLSMode TLSMode

1432}

1433

1434type ClientConfig struct {

1435 IMAP ProtocolConfig

1436 Submission ProtocolConfig

1437}

1438

1439// ClientConfigDomain returns a single IMAP and Submission client configuration for

1440// a domain.

1441func ClientConfigDomain(d dns.Domain) (rconfig ClientConfig, rerr error) {

1442 var haveIMAP, haveSubmission bool

1443

1444 domConf, ok := Conf.Domain(d)

1445 if !ok {

1446 return ClientConfig{}, fmt.Errorf("%w: unknown domain", ErrRequest)

1447 }

1448

1449 gather := func(l config.Listener) (done bool) {

1450 host := Conf.Static.HostnameDomain

1451 if l.Hostname != "" {

1452 host = l.HostnameDomain

1453 }

1454 if domConf.ClientSettingsDomain != "" {

1455 host = domConf.ClientSettingsDNSDomain

1456 }

1457 if !haveIMAP && l.IMAPS.Enabled {

1458 rconfig.IMAP.Host = host

1459 rconfig.IMAP.Port = config.Port(l.IMAPS.Port, 993)

1460 rconfig.IMAP.TLSMode = TLSModeImmediate

1461 haveIMAP = true

1462 }

1463 if !haveIMAP && l.IMAP.Enabled {

1464 rconfig.IMAP.Host = host

1465 rconfig.IMAP.Port = config.Port(l.IMAP.Port, 143)

1466 rconfig.IMAP.TLSMode = TLSModeSTARTTLS

1467 if l.TLS == nil {

1468 rconfig.IMAP.TLSMode = TLSModeNone

1469 }

1470 haveIMAP = true

1471 }

1472 if !haveSubmission && l.Submissions.Enabled {

1473 rconfig.Submission.Host = host

1474 rconfig.Submission.Port = config.Port(l.Submissions.Port, 465)

1475 rconfig.Submission.TLSMode = TLSModeImmediate

1476 haveSubmission = true

1477 }

1478 if !haveSubmission && l.Submission.Enabled {

1479 rconfig.Submission.Host = host

1480 rconfig.Submission.Port = config.Port(l.Submission.Port, 587)

1481 rconfig.Submission.TLSMode = TLSModeSTARTTLS

1482 if l.TLS == nil {

1483 rconfig.Submission.TLSMode = TLSModeNone

1484 }

1485 haveSubmission = true

1486 }

1487 return haveIMAP && haveSubmission

1488 }

1489

1490 // Look at the public listener first. Most likely the intended configuration.

1491 if public, ok := Conf.Static.Listeners["public"]; ok {

1492 if gather(public) {

1493 return

1494 }

1495 }

1496 // Go through the other listeners in consistent order.

1497 names := maps.Keys(Conf.Static.Listeners)

1498 sort.Strings(names)

1499 for _, name := range names {

1500 if gather(Conf.Static.Listeners[name]) {

1501 return

1502 }

1503 }

1504 return ClientConfig{}, fmt.Errorf("%w: no listeners found for imap and/or submission", ErrRequest)

1505}

1506

1507// ClientConfigs holds the client configuration for IMAP/Submission for a

1508// domain.

1509type ClientConfigs struct {

1510 Entries []ClientConfigsEntry

1511}

1512

1513type ClientConfigsEntry struct {

1514 Protocol string

1515 Host dns.Domain

1516 Port int

1517 Listener string

1518 Note string

1519}

1520

1521// ClientConfigsDomain returns the client configs for IMAP/Submission for a

1522// domain.

1523func ClientConfigsDomain(d dns.Domain) (ClientConfigs, error) {

1524 domConf, ok := Conf.Domain(d)

1525 if !ok {

1526 return ClientConfigs{}, fmt.Errorf("%w: unknown domain", ErrRequest)

1527 }

1528

1529 c := ClientConfigs{}

1530 c.Entries = []ClientConfigsEntry{}

1531 var listeners []string

1532

1533 for name := range Conf.Static.Listeners {

1534 listeners = append(listeners, name)

1535 }

1536 sort.Slice(listeners, func(i, j int) bool {

1537 return listeners[i] < listeners[j]

1538 })

1539

1540 note := func(tls bool, requiretls bool) string {

1541 if !tls {

1542 return "plain text, no STARTTLS configured"

1543 }

1544 if requiretls {

1545 return "STARTTLS required"

1546 }

1547 return "STARTTLS optional"

1548 }

1549

1550 for _, name := range listeners {

1551 l := Conf.Static.Listeners[name]

1552 host := Conf.Static.HostnameDomain

1553 if l.Hostname != "" {

1554 host = l.HostnameDomain

1555 }

1556 if domConf.ClientSettingsDomain != "" {

1557 host = domConf.ClientSettingsDNSDomain

1558 }

1559 if l.Submissions.Enabled {

1560 c.Entries = append(c.Entries, ClientConfigsEntry{"Submission (SMTP)", host, config.Port(l.Submissions.Port, 465), name, "with TLS"})

1561 }

1562 if l.IMAPS.Enabled {

1563 c.Entries = append(c.Entries, ClientConfigsEntry{"IMAP", host, config.Port(l.IMAPS.Port, 993), name, "with TLS"})

1564 }

1565 if l.Submission.Enabled {

1566 c.Entries = append(c.Entries, ClientConfigsEntry{"Submission (SMTP)", host, config.Port(l.Submission.Port, 587), name, note(l.TLS != nil, !l.Submission.NoRequireSTARTTLS)})

1567 }

1568 if l.IMAP.Enabled {

1569 c.Entries = append(c.Entries, ClientConfigsEntry{"IMAP", host, config.Port(l.IMAPS.Port, 143), name, note(l.TLS != nil, !l.IMAP.NoRequireSTARTTLS)})

1570 }

1571 }

1572

1573 return c, nil

1574}

1575

1576// IPs returns ip addresses we may be listening/receiving mail on or

1577// connecting/sending from to the outside.

1578func IPs(ctx context.Context, receiveOnly bool) ([]net.IP, error) {

1579 log := pkglog.WithContext(ctx)

1580

1581 // Try to gather all IPs we are listening on by going through the config.