revocation.go 25.9 KB
Newer Older
1 2 3
package irma

import (
4
	"database/sql/driver"
5
	"fmt"
6
	"sort"
7 8
	"time"

9
	"github.com/fxamacker/cbor"
10
	"github.com/getsentry/raven-go"
11
	"github.com/go-errors/errors"
12
	"github.com/hashicorp/go-multierror"
13
	"github.com/jinzhu/gorm"
14
	"github.com/privacybydesign/gabi"
15
	"github.com/privacybydesign/gabi/big"
16
	"github.com/privacybydesign/gabi/revocation"
17
	"github.com/privacybydesign/gabi/signed"
18 19 20

	_ "github.com/jinzhu/gorm/dialects/mysql"
	_ "github.com/jinzhu/gorm/dialects/postgres"
21 22
)

23
type (
Sietse Ringers's avatar
Sietse Ringers committed
24 25 26
	// RevocationStorage stores and retrieves revocation-related data from and to a SQL database,
	// and offers a revocation API for all other irmago code, including a Revoke() method that
	// revokes an earlier issued credential.
27 28 29 30 31 32 33 34 35
	RevocationStorage struct {
		conf     *Configuration
		db       revStorage
		memdb    memRevStorage
		sqlMode  bool
		settings map[CredentialTypeIdentifier]*RevocationSetting

		Keys   RevocationKeys
		client RevocationClient
36 37
	}

Sietse Ringers's avatar
Sietse Ringers committed
38
	// RevocationClient offers an HTTP client to the revocation server endpoints.
39 40 41 42
	RevocationClient struct {
		Conf *Configuration
	}

Sietse Ringers's avatar
Sietse Ringers committed
43 44
	// RevocationKeys contains helper functions for retrieving revocation private and public keys
	// from an irma.Configuration instance.
45 46 47 48
	RevocationKeys struct {
		Conf *Configuration
	}

Sietse Ringers's avatar
Sietse Ringers committed
49
	// RevocationSetting contains revocation settings for a given credential type.
50
	RevocationSetting struct {
51 52 53 54
		Mode                RevocationMode `json:"mode" mapstructure:"mode"`
		PostURLs            []string       `json:"post_urls" mapstructure:"post_urls"`
		RevocationServerURL string         `json:"revocation_server_url" mapstructure:"revocation_server_url"`
		Tolerance           uint           `json:"tolerance" mapstructure:"tolerance"` // in seconds, min 30
55

56 57
		// set to now whenever a new update is received, or when the RA indicates
		// there are no new updates. Thus it specifies up to what time our nonrevocation
58 59
		// guarantees lasts.
		updated time.Time
60 61
	}

Sietse Ringers's avatar
Sietse Ringers committed
62 63
	// RevocationMode specifies for a given credential type what revocation operations are
	// supported, and how the associated data is stored (SQL or memory).
64
	RevocationMode string
65
)
66

67
// Structs corresponding to SQL table rows, ending in Record
68
type (
69 70 71 72 73 74 75
	// signedMessage is a signed.Message with DB (un)marshaling methods.
	signedMessage signed.Message
	// RevocationAttribute is a big.Int with DB (un)marshaling methods.
	RevocationAttribute big.Int
	// eventHash is a revocation.Hash with DB (un)marshaling methods.
	eventHash revocation.Hash

76
	AccumulatorRecord struct {
77 78 79
		CredType  CredentialTypeIdentifier `gorm:"primary_key"`
		Data      signedMessage
		PKCounter uint `gorm:"primary_key;auto_increment:false"`
80 81
	}

82
	EventRecord struct {
83 84
		Index      uint64                   `gorm:"primary_key;column:eventindex"`
		CredType   CredentialTypeIdentifier `gorm:"primary_key"`
85
		PKCounter  uint                     `gorm:"primary_key;auto_increment:false"`
86 87
		E          *RevocationAttribute
		ParentHash eventHash
88 89 90 91
	}

	// IssuanceRecord contains information generated during issuance, needed for later revocation.
	IssuanceRecord struct {
92
		Key        string                   `gorm:"primary_key;column:revocationkey"`
93
		CredType   CredentialTypeIdentifier `gorm:"primary_key"`
94
		PKCounter  uint
95
		Attr       *RevocationAttribute
96 97
		Issued     int64
		ValidUntil int64
98
		RevokedAt  int64 `json:",omitempty"` // 0 if not currently revoked
99
	}
100
)
101

102
const (
Sietse Ringers's avatar
Sietse Ringers committed
103 104
	// RevocationModeRequestor is the default revocation mode in which only RevocationRecord instances
	// are consumed for issuance or verification. Uses an in-memory store.
105
	RevocationModeRequestor RevocationMode = ""
106
	revocationModeRequestor RevocationMode = "requestor" // synonym for RevocationModeRequestor
Sietse Ringers's avatar
Sietse Ringers committed
107 108

	// RevocationModeProxy indicates that this server
109 110
	// (1) allows fetching of revocation update messages from its database,
	// (2) relays all revocation updates it receives to the URLs configured in the containing
Sietse Ringers's avatar
Sietse Ringers committed
111
	// RevocationSetting struct.
112
	// Requires a SQL server to store and retrieve update messages from.
Sietse Ringers's avatar
Sietse Ringers committed
113 114
	RevocationModeProxy RevocationMode = "proxy"

115
	// RevocationModeServer indicates that this is a revocation server for a credential type.
Sietse Ringers's avatar
Sietse Ringers committed
116 117 118
	// IssuanceRecord instances are sent to this server, as well as revocation commands, through
	// revocation sessions or through the RevocationStorage.Revoke() method.
	// Requires a SQL server to store and retrieve all records from and requires the issuer's
119
	// private key to be accessible, in order to revoke and to sign new revocation update messages.
120
	// In addition this mode exposes the same endpoints as RevocationModeProxy.
Sietse Ringers's avatar
Sietse Ringers committed
121 122
	RevocationModeServer RevocationMode = "server"

123
	// RevocationDefaultUpdateEventCount specifies how many revocation events are attached to session requests
Sietse Ringers's avatar
Sietse Ringers committed
124
	// for the client to update its revocation state.
125
	RevocationDefaultUpdateEventCount = 10
126

127 128 129 130 131 132 133 134
	// RevocationRequestorUpdateInterval is the time period in minutes for requestor servers
	// updating their revocation state at th RA.
	RevocationRequestorUpdateInterval uint64 = 5

	// revocationDefaultTolerance is the default tolerance in seconds: nonrevocation should be proved
	// by clients up to maximally this amount of seconds ago at verification time. If not, the
	// server will report the time up until nonrevocation of the attribute is guaranteed to the requestor.
	revocationDefaultTolerance uint = 5 * 60
135 136 137

	// If server mode is enabled for a credential type, then once every so many seconds
	// the timestamp in each accumulator is updated to now.
138
	revocationAccumulatorUpdateInterval uint64 = 60
139 140 141

	// DELETE issuance records of expired credential every so many minutes
	revocationDeleteIssuanceRecordsInterval uint64 = 300
142 143
)

Sietse Ringers's avatar
Sietse Ringers committed
144 145 146
// EnableRevocation creates an initial accumulator for a given credential type. This function is the
// only way to create such an initial accumulator and it must be called before anyone can use
// revocation for this credential type. Requires the issuer private key.
147
func (rs *RevocationStorage) EnableRevocation(typ CredentialTypeIdentifier, sk *revocation.PrivateKey) error {
148
	enabled, err := rs.Exists(typ, sk.Counter)
149 150 151
	if err != nil {
		return err
	}
152 153
	if enabled {
		return errors.New("revocation already enabled")
154 155
	}

156
	update, err := revocation.NewAccumulator(sk)
157 158 159
	if err != nil {
		return err
	}
160

161
	if err = rs.addUpdate(rs.db, typ, update, true); err != nil {
162 163 164 165 166
		return err
	}
	return nil
}

167
// Exists returns whether or not an accumulator exists in the database for the given credential type.
168
func (rs *RevocationStorage) Exists(typ CredentialTypeIdentifier, counter uint) (bool, error) {
169 170
	// only requires sql implementation
	return rs.db.Exists((*AccumulatorRecord)(nil), map[string]interface{}{"cred_type": typ, "pk_counter": counter})
Sietse Ringers's avatar
Sietse Ringers committed
171 172
}

173 174 175
// Revocation update message methods

// UpdateFrom returns all records that a client requires to update its revocation state if it is currently
176 177
// at the specified index, that is, all records whose end index is greater than or equal to
// the specified index.
178
func (rs *RevocationStorage) UpdateFrom(typ CredentialTypeIdentifier, pkcounter uint, index uint64) (*revocation.Update, error) {
179 180 181
	// Only requires SQL implementation
	var update *revocation.Update
	if err := rs.db.Transaction(func(tx revStorage) error {
182
		acc, err := rs.accumulator(tx, typ, pkcounter)
183 184 185 186
		if err != nil {
			return err
		}
		var events []*EventRecord
187
		if err := tx.Find(&events, "cred_type = ? and pk_counter = ? and eventindex >= ?", typ, pkcounter, index); err != nil {
188 189 190 191 192 193 194 195
			return err
		}
		update = rs.newUpdate(acc, events)
		return nil
	}); err != nil {
		return nil, err
	}
	return update, nil
196 197
}

198
func (rs *RevocationStorage) UpdateLatest(typ CredentialTypeIdentifier, count uint64) (map[uint]*revocation.Update, error) {
199
	// TODO what should this function and UpdateFrom return when no records are found?
200
	if rs.sqlMode {
201
		var update map[uint]*revocation.Update
202
		if err := rs.db.Transaction(func(tx revStorage) error {
203 204 205 206 207
			var (
				records []*AccumulatorRecord
				events  []*EventRecord
			)
			if err := tx.Last(&records, map[string]interface{}{"cred_type": typ}); err != nil {
208 209
				return err
			}
210
			if err := tx.Latest(&events, count, map[string]interface{}{"cred_type": typ}); err != nil {
211 212
				return err
			}
213
			update = rs.newUpdates(records, events)
214 215
			return nil
		}); err != nil {
216 217
			return nil, err
		}
218
		return update, nil
219
	} else {
220
		return rs.memdb.Latest(typ, count), nil
221 222 223
	}
}

224 225 226
func (*RevocationStorage) newUpdates(records []*AccumulatorRecord, events []*EventRecord) map[uint]*revocation.Update {
	accs := map[uint]*revocation.SignedAccumulator{}
	for _, r := range records {
227
		accs[r.PKCounter] = r.SignedAccumulator()
228 229 230
	}
	updates := make(map[uint]*revocation.Update, len(accs))
	for _, e := range events {
231
		i := e.PKCounter
232 233 234 235 236 237 238 239 240 241
		if accs[i] == nil {
			continue
		}
		update, present := updates[i]
		if !present {
			update = &revocation.Update{SignedAccumulator: accs[i]}
			updates[i] = update
		}
		update.Events = append(update.Events, e.Event())
	}
242 243 244 245 246
	for _, update := range updates {
		sort.Slice(update.Events, func(i, j int) bool {
			return update.Events[i].Index < update.Events[j].Index
		})
	}
247 248 249 250
	return updates
}

func (rs *RevocationStorage) newUpdate(acc *revocation.SignedAccumulator, events []*EventRecord) *revocation.Update {
251 252
	updates := make([]*revocation.Event, len(events))
	for i := range events {
253
		updates[i] = events[i].Event()
254
	}
255 256 257
	return &revocation.Update{
		SignedAccumulator: acc,
		Events:            updates,
258
	}
259 260
}

261
func (rs *RevocationStorage) AddUpdate(typ CredentialTypeIdentifier, record *revocation.Update) error {
262
	return rs.addUpdate(rs.db, typ, record, false)
263
}
264

265
func (rs *RevocationStorage) addUpdate(tx revStorage, typ CredentialTypeIdentifier, update *revocation.Update, create bool) error {
266
	// Unmarshal and verify the record against the appropriate public key
267
	pk, err := rs.Keys.PublicKey(typ.IssuerIdentifier(), update.SignedAccumulator.PKCounter)
268 269 270
	if err != nil {
		return err
	}
271
	if _, _, err = update.Verify(pk, 0); err != nil {
272 273 274
		return err
	}

275 276
	// Save record
	if rs.sqlMode {
277 278 279 280
		save := tx.Save
		if create {
			save = tx.Insert
		}
281
		if err = save(new(AccumulatorRecord).Convert(typ, update.SignedAccumulator)); err != nil {
282
			return err
283
		}
284
		for _, event := range update.Events {
285
			if err = tx.Insert(new(EventRecord).Convert(typ, update.SignedAccumulator.PKCounter, event)); err != nil {
286 287 288
				return err
			}
		}
289
	} else {
290
		rs.memdb.Insert(typ, update)
291 292
	}

293
	s := rs.getSettings(typ)
294
	s.updated = time.Now()
295 296
	// POST record to listeners, if any, asynchroniously
	go rs.client.PostUpdate(typ, s.PostURLs, update)
297 298 299

	return nil
}
300

301 302 303 304
// Issuance records

func (rs *RevocationStorage) AddIssuanceRecord(r *IssuanceRecord) error {
	return rs.db.Insert(r)
305 306
}

307
func (rs *RevocationStorage) IssuanceRecord(typ CredentialTypeIdentifier, key string) (*IssuanceRecord, error) {
308
	var r IssuanceRecord
309
	err := rs.db.Last(&r, map[string]interface{}{"cred_type": typ, "revocationkey": key})
310 311
	if err != nil {
		return nil, err
312
	}
313 314
	return &r, nil
}
315

316 317
// Revocation methods

Sietse Ringers's avatar
Sietse Ringers committed
318 319
// Revoke revokes the credential specified by key if found within the current database,
// by updating its revocation time to now, removing its revocation attribute from the current accumulator,
320
// and updating the revocation database on disk.
321
func (rs *RevocationStorage) Revoke(typ CredentialTypeIdentifier, key string) error {
Sietse Ringers's avatar
Sietse Ringers committed
322 323
	if rs.getSettings(typ).Mode != RevocationModeServer {
		return errors.Errorf("cannot revoke %s", typ)
324
	}
325

326 327
	return rs.db.Transaction(func(tx revStorage) error {
		var err error
328 329
		issrecord, err := rs.IssuanceRecord(typ, key)
		if err != nil {
330 331
			return err
		}
332 333
		issrecord.RevokedAt = time.Now().UnixNano()
		if err = tx.Save(&issrecord); err != nil {
334 335
			return err
		}
336
		sk, err := rs.Keys.PrivateKey(typ.IssuerIdentifier(), issrecord.PKCounter)
337 338 339
		if err != nil {
			return err
		}
340
		return rs.revokeAttr(tx, typ, sk, issrecord.Attr)
341 342 343
	})
}

344
func (rs *RevocationStorage) revokeAttr(tx revStorage, typ CredentialTypeIdentifier, sk *revocation.PrivateKey, e *RevocationAttribute) error {
345
	sacc, err := rs.accumulator(tx, typ, sk.Counter)
346 347 348
	if err != nil {
		return err
	}
349
	if sacc == nil {
350 351
		return errors.Errorf("cannot revoke for type %s, not enabled yet", typ)
	}
352
	cur := sacc.Accumulator
353
	var parent EventRecord
354
	if err = rs.db.Last(&parent, map[string]interface{}{"cred_type": typ, "pk_counter": sk.Counter}); err != nil {
355 356
		return err
	}
357

358
	update, err := cur.Remove(sk, (*big.Int)(e), parent.Event())
359 360 361
	if err != nil {
		return err
	}
362
	if err = rs.addUpdate(tx, typ, update, false); err != nil {
363 364 365 366 367
		return err
	}
	return nil
}

368
// Accumulator methods
369

370
func (rs *RevocationStorage) Accumulator(typ CredentialTypeIdentifier, pkcounter uint) (
371
	*revocation.SignedAccumulator, error,
372 373 374 375
) {
	return rs.accumulator(rs.db, typ, pkcounter)
}

376
// accumulator retrieves, verifies and deserializes the accumulator of the given type and key.
377
func (rs *RevocationStorage) accumulator(tx revStorage, typ CredentialTypeIdentifier, pkcounter uint) (
378
	*revocation.SignedAccumulator, error,
379 380
) {
	var err error
381
	var sacc *revocation.SignedAccumulator
382
	if rs.sqlMode {
383
		record := &AccumulatorRecord{}
384
		if err = tx.Last(record, map[string]interface{}{"cred_type": typ, "pk_counter": pkcounter}); err != nil {
385
			if gorm.IsRecordNotFoundError(err) {
386
				return nil, nil
387
			}
388
		}
389
		sacc = record.SignedAccumulator()
390
	} else {
391
		sacc = rs.memdb.SignedAccumulator(typ, pkcounter)
392
		if sacc == nil {
393
			return nil, nil
394
		}
395 396
	}

397
	pk, err := rs.Keys.PublicKey(typ.IssuerIdentifier(), sacc.PKCounter)
398
	if err != nil {
399
		return nil, err
400
	}
401
	_, err = sacc.UnmarshalVerify(pk)
402
	if err != nil {
403
		return nil, err
404
	}
405
	return sacc, nil
406 407
}

408 409 410
// Methods to update from remote revocation server

func (rs *RevocationStorage) UpdateDB(typ CredentialTypeIdentifier) error {
411
	updates, err := rs.client.FetchUpdateLatest(typ, RevocationDefaultUpdateEventCount)
412
	if err != nil {
413
		return err
414
	}
415 416 417 418
	for _, u := range updates {
		if err = rs.AddUpdate(typ, u); err != nil {
			return err
		}
419 420 421 422
	}
	// bump updated even if no new records were added
	rs.getSettings(typ).updated = time.Now()
	return nil
423 424
}

Sietse Ringers's avatar
Sietse Ringers committed
425
func (rs *RevocationStorage) UpdateIfOld(typ CredentialTypeIdentifier) error {
426
	settings := rs.getSettings(typ)
427
	// update 10 seconds before the maximum, to stay below it
428
	if settings.updated.Before(time.Now().Add(time.Duration(-settings.Tolerance+10) * time.Second)) {
429
		Logger.WithField("credtype", typ).Tracef("fetching revocation updates")
430
		if err := rs.UpdateDB(typ); err != nil {
431 432 433 434 435 436
			return err
		}
	}
	return nil
}

437 438
// SaveIssuanceRecord either stores the issuance record locally, if we are the revocation server of
// the crecential type, or it signs and sends it to the remote revocation server.
439 440 441 442 443 444 445 446 447
func (rs *RevocationStorage) SaveIssuanceRecord(typ CredentialTypeIdentifier, rec *IssuanceRecord, sk *gabi.PrivateKey) error {
	credtype := rs.conf.CredentialTypes[typ]
	if credtype == nil {
		return errors.New("unknown credential type")
	}
	if !credtype.SupportsRevocation() {
		return errors.New("cannot save issuance record: credential type does not support revocation")
	}

448
	// Just store it if we are the revocation server for this credential type
449 450
	settings := rs.getSettings(typ)
	if settings.Mode == RevocationModeServer {
451
		return rs.AddIssuanceRecord(rec)
452 453
	}

454
	// We have to send it, sign it first
455
	if settings.RevocationServerURL == "" {
456 457
		return errors.New("cannot send issuance record: no server_url configured")
	}
458
	rsk, err := sk.RevocationKey()
459 460 461
	if err != nil {
		return err
	}
462
	return rs.client.PostIssuanceRecord(typ, rsk, rec, settings.RevocationServerURL)
463 464
}

465 466
// Misscelaneous methods

467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496
func (rs *RevocationStorage) updateAccumulatorTimes(types []CredentialTypeIdentifier) error {
	return rs.db.Transaction(func(tx revStorage) error {
		var err error
		var records []AccumulatorRecord
		Logger.Tracef("updating accumulator times")
		if err = tx.Find(&records, "cred_type in (?)", types); err != nil {
			return err
		}
		for _, r := range records {
			pk, err := rs.Keys.PublicKey(r.CredType.IssuerIdentifier(), r.PKCounter)
			if err != nil {
				return err
			}
			sk, err := rs.Keys.PrivateKey(r.CredType.IssuerIdentifier(), r.PKCounter)
			if err != nil {
				return err
			}
			acc, err := r.SignedAccumulator().UnmarshalVerify(pk)
			if err != nil {
				return err
			}
			acc.Time = time.Now().Unix()
			sacc, err := acc.Sign(sk)
			if err != nil {
				return err
			}
			r.Data = signedMessage(sacc.Data)
			if err = tx.Save(r); err != nil {
				return err
			}
497 498 499 500 501

			s := rs.getSettings(r.CredType)
			s.updated = time.Now()
			// POST record to listeners, if any, asynchroniously
			go rs.client.PostUpdate(r.CredType, s.PostURLs, &revocation.Update{SignedAccumulator: sacc})
502 503 504 505 506
		}
		return nil
	})
}

507
func (rs *RevocationStorage) Load(debug bool, dbtype, connstr string, settings map[CredentialTypeIdentifier]*RevocationSetting) error {
508
	var t *CredentialTypeIdentifier
509
	var ourtypes []CredentialTypeIdentifier
510 511
	for typ, s := range settings {
		switch s.Mode {
512
		case RevocationModeServer:
513
			if s.RevocationServerURL != "" {
514 515
				return errors.New("server_url cannot be combined with server mode")
			}
516
			ourtypes = append(ourtypes, typ)
517
			t = &typ
518 519 520
		case RevocationModeProxy:
			t = &typ
		case RevocationModeRequestor: // noop
521 522
		case revocationModeRequestor:
			s.Mode = RevocationModeRequestor
523
		default:
524 525
			return errors.Errorf(`invalid revocation mode "%s" for %s (supported: "%s" (or empty string), "%s", "%s")`,
				s.Mode, typ, revocationModeRequestor, RevocationModeServer, RevocationModeProxy)
526
		}
527
	}
528 529 530
	if t != nil && connstr == "" {
		return errors.Errorf("revocation mode for %s requires SQL database but no connection string given", *t)
	}
531

532 533 534 535 536 537 538 539
	if len(ourtypes) > 0 {
		rs.conf.Scheduler.Every(revocationAccumulatorUpdateInterval).Seconds().Do(func() {
			if err := rs.updateAccumulatorTimes(ourtypes); err != nil {
				err = errors.WrapPrefix(err, "failed to write updated accumulator record", 0)
				raven.CaptureError(err, nil)
			}
		})
	}
540 541 542 543 544 545 546 547 548
	rs.conf.Scheduler.Every(revocationDeleteIssuanceRecordsInterval).Minutes().Do(func() {
		if !rs.sqlMode {
			return
		}
		if err := rs.db.Delete(IssuanceRecord{}, "valid_until < ?", time.Now().UnixNano()); err != nil {
			err = errors.WrapPrefix(err, "failed to delete expired issuance records", 0)
			raven.CaptureError(err, nil)
		}
	})
549

550 551 552 553 554 555
	if connstr == "" {
		Logger.Trace("Using memory revocation database")
		rs.memdb = newMemStorage()
		rs.sqlMode = false
	} else {
		Logger.Trace("Connecting to revocation SQL database")
556
		db, err := newSqlStorage(debug, dbtype, connstr)
557
		if err != nil {
558
			return err
559
		}
560 561
		rs.db = db
		rs.sqlMode = true
562
	}
563 564 565 566 567
	if settings != nil {
		rs.settings = settings
	} else {
		rs.settings = map[CredentialTypeIdentifier]*RevocationSetting{}
	}
568
	for id, settings := range rs.settings {
569
		if settings.Tolerance != 0 && settings.Tolerance < 30 {
570
			return errors.Errorf("max_nonrev_duration setting for %s must be at least 30 seconds, was %d",
571
				id, settings.Tolerance)
572 573
		}
	}
574 575 576
	rs.client = RevocationClient{Conf: rs.conf}
	rs.Keys = RevocationKeys{Conf: rs.conf}
	return nil
577 578
}

579 580 581
func (rs *RevocationStorage) Close() error {
	if rs.db != nil {
		return rs.db.Close()
582 583 584 585
	}
	return nil
}

586
// SetRevocationUpdates retrieves the latest revocation records from the database, and attaches
587 588
// them to the request, for each credential type for which a nonrevocation proof is requested in
// b.Revocation.
589
func (rs *RevocationStorage) SetRevocationUpdates(b *BaseRequest) error {
590 591
	if len(b.Revocation) == 0 {
		return nil
592
	}
593
	var err error
594
	b.RevocationUpdates = make(map[CredentialTypeIdentifier]map[uint]*revocation.Update, len(b.Revocation))
595
	for _, credid := range b.Revocation {
596 597 598
		if !rs.conf.CredentialTypes[credid].SupportsRevocation() {
			return errors.Errorf("cannot request nonrevocation proof for %s: revocation not enabled in scheme")
		}
Sietse Ringers's avatar
Sietse Ringers committed
599
		if err = rs.UpdateIfOld(credid); err != nil {
600 601 602 603 604 605 606 607 608 609 610 611
			updated := rs.getSettings(credid).updated
			if !updated.IsZero() {
				Logger.Warnf("failed to fetch revocation updates for %s, nonrevocation is guaranteed only until %s ago:",
					credid, time.Now().Sub(updated).String())
				Logger.Warn(err)
			} else {
				Logger.Errorf("revocation is disabled for %s: failed to fetch revocation updates and none are known locally", credid)
				Logger.Warn(err)
				// We can offer no nonrevocation guarantees at all while the requestor explicitly
				// asked for it; fail the session by returning an error
				return err
			}
612
		}
613
		b.RevocationUpdates[credid], err = rs.UpdateLatest(credid, RevocationDefaultUpdateEventCount)
614 615 616
		if err != nil {
			return err
		}
617
	}
618 619 620 621 622 623
	return nil
}

func (rs *RevocationStorage) getSettings(typ CredentialTypeIdentifier) *RevocationSetting {
	if rs.settings[typ] == nil {
		rs.settings[typ] = &RevocationSetting{}
624
	}
625
	s := rs.settings[typ]
626 627
	if s.Tolerance == 0 {
		s.Tolerance = revocationDefaultTolerance
628 629
	}
	return s
630 631
}

632
func (client RevocationClient) PostUpdate(typ CredentialTypeIdentifier, urls []string, update *revocation.Update) {
633
	transport := NewHTTPTransport("")
634
	transport.Binary = true
635
	for _, url := range urls {
636 637
		err := transport.Post(fmt.Sprintf("%s/revocation/update/%s", url, typ.String()), nil, update)
		if err != nil {
638 639
			Logger.Warn("error sending revocation update", err)
		}
640
	}
641 642
}

643 644 645 646 647
func (client RevocationClient) PostIssuanceRecord(typ CredentialTypeIdentifier, sk *revocation.PrivateKey, rec *IssuanceRecord, url string) error {
	message, err := signed.MarshalSign(sk.ECDSA, rec)
	if err != nil {
		return err
	}
648
	return NewHTTPTransport(url).Post(
649
		fmt.Sprintf("revocation/issuancerecord/%s/%d", typ, sk.Counter), nil, []byte(message),
650 651 652 653
	)
}

// FetchRevocationRecords gets revocation update messages from the revocation server, of the specified index and greater.
654
func (client RevocationClient) FetchUpdateFrom(typ CredentialTypeIdentifier, pkcounter uint, index uint64) (*revocation.Update, error) {
655 656 657
	update := &revocation.Update{}
	return update, client.getMultiple(
		client.Conf.CredentialTypes[typ].RevocationServers,
658
		fmt.Sprintf("revocation/updatefrom/%s/%d/%d", typ, pkcounter, index),
659 660
		&update,
	)
661
}
662

663 664 665 666 667 668 669
func (client RevocationClient) FetchUpdateLatest(typ CredentialTypeIdentifier, count uint64) (map[uint]*revocation.Update, error) {
	update := map[uint]*revocation.Update{}
	return update, client.getMultiple(
		client.Conf.CredentialTypes[typ].RevocationServers,
		fmt.Sprintf("revocation/updatelatest/%s/%d", typ, count),
		&update,
	)
670 671
}

672
func (RevocationClient) getMultiple(urls []string, path string, dest interface{}) error {
673 674 675 676 677
	var (
		errs      multierror.Error
		transport = NewHTTPTransport("")
	)
	transport.Binary = true
678
	for _, url := range urls {
679
		transport.Server = url
680
		err := transport.Get(path, dest)
681
		if err == nil {
682
			return nil
683 684 685
		} else {
			errs.Errors = append(errs.Errors, err)
		}
686
	}
687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702
	return &errs
}

func (rs RevocationKeys) PrivateKeyLatest(issid IssuerIdentifier) (*revocation.PrivateKey, error) {
	sk, err := rs.Conf.PrivateKeyLatest(issid)
	if err != nil {
		return nil, err
	}
	if sk == nil {
		return nil, errors.Errorf("unknown private key: %s", issid)
	}
	revsk, err := sk.RevocationKey()
	if err != nil {
		return nil, err
	}
	return revsk, nil
703 704
}

705
func (rs RevocationKeys) PrivateKey(issid IssuerIdentifier, counter uint) (*revocation.PrivateKey, error) {
706
	sk, err := rs.Conf.PrivateKey(issid, counter)
707
	if err != nil {
708
		return nil, err
709 710
	}
	if sk == nil {
711
		return nil, errors.Errorf("unknown private key: %s", issid)
712
	}
713
	revsk, err := sk.RevocationKey()
714
	if err != nil {
715
		return nil, err
716
	}
717 718
	return revsk, nil
}
719

720
func (rs RevocationKeys) PublicKey(issid IssuerIdentifier, counter uint) (*revocation.PublicKey, error) {
721
	pk, err := rs.Conf.PublicKey(issid, counter)
722
	if err != nil {
723
		return nil, err
724
	}
725 726
	if pk == nil {
		return nil, errors.Errorf("unknown public key: %s-%d", issid, counter)
727
	}
728 729 730
	revpk, err := pk.RevocationKey()
	if err != nil {
		return nil, err
731
	}
732
	return revpk, nil
733
}
734 735 736 737 738 739 740 741 742 743 744

// Conversion methods to/from database structs, SQL table rows, gob

func (e *EventRecord) Event() *revocation.Event {
	return &revocation.Event{
		Index:      e.Index,
		E:          (*big.Int)(e.E),
		ParentHash: revocation.Hash(e.ParentHash),
	}
}

745
func (e *EventRecord) Convert(typ CredentialTypeIdentifier, pkcounter uint, event *revocation.Event) *EventRecord {
746 747 748 749 750
	*e = EventRecord{
		Index:      event.Index,
		E:          (*RevocationAttribute)(event.E),
		ParentHash: eventHash(event.ParentHash),
		CredType:   typ,
751
		PKCounter:  pkcounter,
752 753 754 755 756 757
	}
	return e
}

func (a *AccumulatorRecord) SignedAccumulator() *revocation.SignedAccumulator {
	return &revocation.SignedAccumulator{
758 759
		PKCounter: a.PKCounter,
		Data:      signed.Message(a.Data),
760 761 762 763 764
	}
}

func (a *AccumulatorRecord) Convert(typ CredentialTypeIdentifier, sacc *revocation.SignedAccumulator) *AccumulatorRecord {
	*a = AccumulatorRecord{
765 766 767
		Data:      signedMessage(sacc.Data),
		PKCounter: sacc.PKCounter,
		CredType:  typ,
768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804