Add GetContactCode call, add DH flag (#1367)

This PR does a few things:

1) Add a call GetContactCode to check whether we have a bundle for a
given user.

2) Add a DH flag to the API (non-breaking change), for those messages
that we want to target all devices (contact-requests for example).

3) Fixes a few small issues with installations, namely if for example a
messages is sent without a bundle (currently not done by any client),
we still infer installation info, so that we can communicate securely
and making it truly optional.

api/backend.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"context"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"math/big"
@@ -556,6 +557,35 @@ func (b *StatusBackend) CreateContactCode() (string, error) {
 	return bundle.ToBase64()
 }
 
+// GetContactCode return the latest contact code
+func (b *StatusBackend) GetContactCode(identity string) (string, error) {
+	st, err := b.statusNode.ShhExtService()
+	if err != nil {
+		return "", err
+	}
+
+	publicKeyBytes, err := hex.DecodeString(identity)
+	if err != nil {
+		return "", err
+	}
+
+	publicKey, err := ethcrypto.UnmarshalPubkey(publicKeyBytes)
+	if err != nil {
+		return "", err
+	}
+
+	bundle, err := st.GetPublicBundle(publicKey)
+	if err != nil {
+		return "", err
+	}
+
+	if bundle == nil {
+		return "", nil
+	}
+
+	return bundle.ToBase64()
+}
+
 // ProcessContactCode process and adds the someone else's bundle
 func (b *StatusBackend) ProcessContactCode(contactCode string) error {
 	selectedChatAccount, err := b.AccountManager().SelectedChatAccount()

lib/library.go

@@ -70,6 +70,24 @@ func ProcessContactCode(bundleString *C.char) *C.char {
 	return nil
 }
 
+// Get an X3DH bundle
+//export GetContactCode
+func GetContactCode(identityString *C.char) *C.char {
+	bundle, err := statusBackend.GetContactCode(C.GoString(identityString))
+	if err != nil {
+		return makeJSONResponse(err)
+	}
+
+	data, err := json.Marshal(struct {
+		ContactCode string `json:"code"`
+	}{ContactCode: bundle})
+	if err != nil {
+		return makeJSONResponse(err)
+	}
+
+	return C.CString(string(data))
+}
+
 //export ExtractIdentityFromContactCode
 func ExtractIdentityFromContactCode(bundleString *C.char) *C.char {
 	bundle := C.GoString(bundleString)

mobile/status.go

@@ -501,3 +501,21 @@ func SetMobileSignalHandler(handler SignalHandler) {
 func SetSignalEventCallback(cb unsafe.Pointer) {
 	signal.SetSignalEventCallback(cb)
 }
+
+// Get an X3DH bundle
+//export GetContactCode
+func GetContactCode(identity string) string {
+	bundle, err := statusBackend.GetContactCode(identity)
+	if err != nil {
+		return makeJSONResponse(err)
+	}
+
+	data, err := json.Marshal(struct {
+		ContactCode string `json:"code"`
+	}{ContactCode: bundle})
+	if err != nil {
+		return makeJSONResponse(err)
+	}
+
+	return string(data)
+}

services/shhext/api.go

@@ -422,7 +422,7 @@ func (api *PublicAPI) SendPublicMessage(ctx context.Context, msg chat.SendPublic
 }
 
 // SendDirectMessage sends a 1:1 chat message to the underlying transport
-func (api *PublicAPI) SendDirectMessage(ctx context.Context, msg chat.SendDirectMessageRPC) ([]hexutil.Bytes, error) {
+func (api *PublicAPI) SendDirectMessage(ctx context.Context, msg chat.SendDirectMessageRPC) (hexutil.Bytes, error) {
 	if !api.service.pfsEnabled {
 		return nil, ErrPFSNotEnabled
 	}
@@ -438,29 +438,26 @@ func (api *PublicAPI) SendDirectMessage(ctx context.Context, msg chat.SendDirect
 	}
 
 	// This is transport layer-agnostic
-	protocolMessages, err := api.service.protocol.BuildDirectMessage(privateKey, msg.Payload, publicKey)
+	var protocolMessage []byte
+
+	if msg.DH {
+		protocolMessage, err = api.service.protocol.BuildDHMessage(privateKey, &privateKey.PublicKey, msg.Payload)
+	} else {
+		protocolMessage, err = api.service.protocol.BuildDirectMessage(privateKey, publicKey, msg.Payload)
+	}
+
 	if err != nil {
 		return nil, err
 	}
 
-	var response []hexutil.Bytes
-
-	for key, message := range protocolMessages {
-		msg.PubKey = crypto.FromECDSAPub(key)
 	// Enrich with transport layer info
-		whisperMessage := chat.DirectMessageToWhisper(msg, message)
+	whisperMessage := chat.DirectMessageToWhisper(msg, protocolMessage)
 
 	// And dispatch
-		hash, err := api.Post(ctx, whisperMessage)
+	return api.Post(ctx, whisperMessage)
-		if err != nil {
-			return nil, err
-		}
-		response = append(response, hash)
-
-	}
-	return response, nil
 }
 
+// DEPRECATED: use SendDirectMessage with DH flag
 // SendPairingMessage sends a 1:1 chat message to our own devices to initiate a pairing session
 func (api *PublicAPI) SendPairingMessage(ctx context.Context, msg chat.SendDirectMessageRPC) ([]hexutil.Bytes, error) {
 	if !api.service.pfsEnabled {
@@ -477,7 +474,7 @@ func (api *PublicAPI) SendPairingMessage(ctx context.Context, msg chat.SendDirec
 		return nil, err
 	}
 
-	protocolMessage, err := api.service.protocol.BuildPairingMessage(privateKey, msg.Payload)
+	protocolMessage, err := api.service.protocol.BuildDHMessage(privateKey, &privateKey.PublicKey, msg.Payload)
 	if err != nil {
 		return nil, err
 	}
@@ -497,57 +494,6 @@ func (api *PublicAPI) SendPairingMessage(ctx context.Context, msg chat.SendDirec
 	return response, nil
 }
 
-// SendGroupMessage sends a group messag chat message to the underlying transport
-func (api *PublicAPI) SendGroupMessage(ctx context.Context, msg chat.SendGroupMessageRPC) ([]hexutil.Bytes, error) {
-	if !api.service.pfsEnabled {
-		return nil, ErrPFSNotEnabled
-	}
-
-	// To be completely agnostic from whisper we should not be using whisper to store the key
-	privateKey, err := api.service.w.GetPrivateKey(msg.Sig)
-	if err != nil {
-		return nil, err
-	}
-
-	var keys []*ecdsa.PublicKey
-
-	for _, k := range msg.PubKeys {
-		publicKey, err := crypto.UnmarshalPubkey(k)
-		if err != nil {
-			return nil, err
-		}
-		keys = append(keys, publicKey)
-	}
-
-	// This is transport layer-agnostic
-	protocolMessages, err := api.service.protocol.BuildDirectMessage(privateKey, msg.Payload, keys...)
-	if err != nil {
-		return nil, err
-	}
-
-	var response []hexutil.Bytes
-
-	for key, message := range protocolMessages {
-		directMessage := chat.SendDirectMessageRPC{
-			PubKey:  crypto.FromECDSAPub(key),
-			Payload: msg.Payload,
-			Sig:     msg.Sig,
-		}
-
-		// Enrich with transport layer info
-		whisperMessage := chat.DirectMessageToWhisper(directMessage, message)
-
-		// And dispatch
-		hash, err := api.Post(ctx, whisperMessage)
-		if err != nil {
-			return nil, err
-		}
-		response = append(response, hash)
-
-	}
-	return response, nil
-}
-
 func (api *PublicAPI) processPFSMessage(msg *whisper.Message) error {
 
 	privateKeyID := api.service.w.SelectedKeyPairID()
@@ -567,21 +513,26 @@ func (api *PublicAPI) processPFSMessage(msg *whisper.Message) error {
 
 	response, err := api.service.protocol.HandleMessage(privateKey, publicKey, msg.Payload)
 
+	switch err {
+	case nil:
+		// Set the decrypted payload
+		msg.Payload = response
+	case chat.ErrDeviceNotFound:
 		// Notify that someone tried to contact us using an invalid bundle
-	if err == chat.ErrDeviceNotFound && privateKey.PublicKey != *publicKey {
+		if privateKey.PublicKey != *publicKey {
 			api.log.Warn("Device not found, sending signal", "err", err)
 			keyString := fmt.Sprintf("0x%x", crypto.FromECDSAPub(publicKey))
 			handler := EnvelopeSignalHandler{}
 			handler.DecryptMessageFailed(keyString)
-		return nil
-	} else if err != nil {
-		// Ignore errors for now as those might be non-pfs messages
-		api.log.Error("Failed handling message with error", "err", err)
-		return nil
 		}
+	case chat.ErrNotProtocolMessage:
+		// Not using encryption, pass directly to the layer below
+		api.log.Debug("Not a protocol message", "err", err)
+	default:
+		// Log and pass to the client, even if failed to decrypt
+		api.log.Error("Failed handling message with error", "err", err)
 
-	// Add unencrypted payload
+	}
-	msg.Payload = response
 
 	return nil
 }

services/shhext/chat/encryption.go

@@ -285,6 +285,11 @@ func (s *EncryptionService) DecryptPayload(myIdentityKey *ecdsa.PrivateKey, thei
 			return nil, err
 		}
 
+		// Add installations with a timestamp of 0, as we don't have bundle informations
+		if err = s.persistence.AddInstallations(theirIdentityKeyC, 0, []string{theirInstallationID}, true); err != nil {
+			return nil, err
+		}
+
 		// We mark the exchange as successful so we stop sending x3dh header
 		if err = s.persistence.RatchetInfoConfirmed(drHeader.GetId(), theirIdentityKeyC, theirInstallationID); err != nil {
 			s.log.Error("Could not confirm ratchet info", "err", err)
@@ -450,13 +455,8 @@ func (s *EncryptionService) EncryptPayloadWithDH(theirIdentityKey *ecdsa.PublicK
 	return response, nil
 }
 
-// EncryptPayload returns a new DirectMessageProtocol with a given payload encrypted, given a recipient's public key and the sender private identity key
+// GetPublicBundle returns the active installations bundles for a given user
-// TODO: refactor this
+func (s *EncryptionService) GetPublicBundle(theirIdentityKey *ecdsa.PublicKey) (*Bundle, error) {
-// nolint: gocyclo
-func (s *EncryptionService) EncryptPayload(theirIdentityKey *ecdsa.PublicKey, myIdentityKey *ecdsa.PrivateKey, payload []byte) (map[string]*DirectMessageProtocol, error) {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-
 	theirIdentityKeyC := ecrypto.CompressPubkey(theirIdentityKey)
 
 	installationIDs, err := s.persistence.GetActiveInstallations(s.config.MaxInstallations, theirIdentityKeyC)
@@ -464,25 +464,43 @@ func (s *EncryptionService) EncryptPayload(theirIdentityKey *ecdsa.PublicKey, my
 		return nil, err
 	}
 
-	// Get their latest bundle
+	return s.persistence.GetPublicBundle(theirIdentityKey, installationIDs)
-	theirBundle, err := s.persistence.GetPublicBundle(theirIdentityKey, installationIDs)
+}
+
+// EncryptPayload returns a new DirectMessageProtocol with a given payload encrypted, given a recipient's public key and the sender private identity key
+// TODO: refactor this
+// nolint: gocyclo
+func (s *EncryptionService) EncryptPayload(theirIdentityKey *ecdsa.PublicKey, myIdentityKey *ecdsa.PrivateKey, payload []byte) (map[string]*DirectMessageProtocol, error) {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	s.log.Debug("Sending message", "theirKey", theirIdentityKey)
+
+	theirIdentityKeyC := ecrypto.CompressPubkey(theirIdentityKey)
+
+	// Get their installationIds
+	installationIds, err := s.persistence.GetActiveInstallations(s.config.MaxInstallations, theirIdentityKeyC)
 	if err != nil {
 		return nil, err
 	}
 
 	// We don't have any, send a message with DH
-	if theirBundle == nil && !bytes.Equal(theirIdentityKeyC, ecrypto.CompressPubkey(&myIdentityKey.PublicKey)) {
+	if installationIds == nil && !bytes.Equal(theirIdentityKeyC, ecrypto.CompressPubkey(&myIdentityKey.PublicKey)) {
 		return s.EncryptPayloadWithDH(theirIdentityKey, payload)
 	}
 
 	response := make(map[string]*DirectMessageProtocol)
 
-	for installationID, signedPreKeyContainer := range theirBundle.GetSignedPreKeys() {
+	for _, installationID := range installationIds {
+		s.log.Debug("Processing installation", "installationID", installationID)
 		if s.config.InstallationID == installationID {
 			continue
 		}
+		bundle, err := s.persistence.GetPublicBundle(theirIdentityKey, []string{installationID})
+		if err != nil {
+			return nil, err
+		}
 
-		theirSignedPreKey := signedPreKeyContainer.GetSignedPreKey()
 		// See if a session is there already
 		drInfo, err := s.persistence.GetAnyRatchetInfo(theirIdentityKeyC, installationID)
 		if err != nil {
@@ -490,6 +508,7 @@ func (s *EncryptionService) EncryptPayload(theirIdentityKey *ecdsa.PublicKey, my
 		}
 
 		if drInfo != nil {
+			s.log.Debug("Found DR info", "installationID", installationID)
 			encryptedPayload, drHeader, err := s.encryptUsingDR(theirIdentityKey, drInfo, payload)
 			if err != nil {
 				return nil, err
@@ -511,6 +530,18 @@ func (s *EncryptionService) EncryptPayload(theirIdentityKey *ecdsa.PublicKey, my
 			continue
 		}
 
+		theirSignedPreKeyContainer := bundle.GetSignedPreKeys()[installationID]
+
+		// This should not be nil at this point
+		if theirSignedPreKeyContainer == nil {
+			s.log.Warn("Could not find either a ratchet info or a bundle for installationId", "installationID", installationID)
+			continue
+
+		}
+		s.log.Debug("DR info not found, using bundle", "installationID", installationID)
+
+		theirSignedPreKey := theirSignedPreKeyContainer.GetSignedPreKey()
+
 		sharedKey, ourEphemeralKey, err := s.keyFromActiveX3DH(theirIdentityKeyC, theirSignedPreKey, myIdentityKey)
 		if err != nil {
 			return nil, err
@@ -549,5 +580,7 @@ func (s *EncryptionService) EncryptPayload(theirIdentityKey *ecdsa.PublicKey, my
 		}
 	}
 
+	s.log.Debug("Built message", "theirKey", theirIdentityKey)
+
 	return response, nil
 }

services/shhext/chat/protocol.go

@@ -15,6 +15,8 @@ type ProtocolService struct {
 	Enabled             bool
 }
 
+var ErrNotProtocolMessage = errors.New("Not a protocol message")
+
 // NewProtocolService creates a new ProtocolService instance
 func NewProtocolService(encryption *EncryptionService, addedBundlesHandler func([]IdentityAndIDPair)) *ProtocolService {
 	return &ProtocolService{
@@ -62,9 +64,7 @@ func (p *ProtocolService) BuildPublicMessage(myIdentityKey *ecdsa.PrivateKey, pa
 }
 
 // BuildDirectMessage marshals a 1:1 chat message given the user identity private key, the recipient's public key, and a payload
-func (p *ProtocolService) BuildDirectMessage(myIdentityKey *ecdsa.PrivateKey, payload []byte, theirPublicKeys ...*ecdsa.PublicKey) (map[*ecdsa.PublicKey][]byte, error) {
+func (p *ProtocolService) BuildDirectMessage(myIdentityKey *ecdsa.PrivateKey, publicKey *ecdsa.PublicKey, payload []byte) ([]byte, error) {
-	response := make(map[*ecdsa.PublicKey][]byte)
-	for _, publicKey := range theirPublicKeys {
 	// Encrypt payload
 	encryptionResponse, err := p.encryption.EncryptPayload(publicKey, myIdentityKey, payload)
 	if err != nil {
@@ -78,22 +78,13 @@ func (p *ProtocolService) BuildDirectMessage(myIdentityKey *ecdsa.PrivateKey, pa
 		DirectMessage:  encryptionResponse,
 	}
 
-		payload, err := p.addBundleAndMarshal(myIdentityKey, protocolMessage, true)
+	return p.addBundleAndMarshal(myIdentityKey, protocolMessage, true)
-		if err != nil {
-			return nil, err
 }
 
-		if len(payload) != 0 {
+// BuildDHMessage builds a message with DH encryption so that it can be decrypted by any other device.
-			response[publicKey] = payload
+func (p *ProtocolService) BuildDHMessage(myIdentityKey *ecdsa.PrivateKey, destination *ecdsa.PublicKey, payload []byte) ([]byte, error) {
-		}
-	}
-	return response, nil
-}
-
-// BuildPairingMessage sends a message to our own devices using DH so that it can be decrypted by any other device.
-func (p *ProtocolService) BuildPairingMessage(myIdentityKey *ecdsa.PrivateKey, payload []byte) ([]byte, error) {
 	// Encrypt payload
-	encryptionResponse, err := p.encryption.EncryptPayloadWithDH(&myIdentityKey.PublicKey, payload)
+	encryptionResponse, err := p.encryption.EncryptPayloadWithDH(destination, payload)
 	if err != nil {
 		p.log.Error("encryption-service", "error encrypting payload", err)
 		return nil, err
@@ -128,6 +119,11 @@ func (p *ProtocolService) DisableInstallation(myIdentityKey *ecdsa.PublicKey, in
 	return p.encryption.DisableInstallation(myIdentityKey, installationID)
 }
 
+// GetPublicBundle retrieves a public bundle given an identity
+func (p *ProtocolService) GetPublicBundle(theirIdentityKey *ecdsa.PublicKey) (*Bundle, error) {
+	return p.encryption.GetPublicBundle(theirIdentityKey)
+}
+
 // HandleMessage unmarshals a message and processes it, decrypting it if it is a 1:1 message.
 func (p *ProtocolService) HandleMessage(myIdentityKey *ecdsa.PrivateKey, theirPublicKey *ecdsa.PublicKey, payload []byte) ([]byte, error) {
 	if p.encryption == nil {
@@ -138,7 +134,7 @@ func (p *ProtocolService) HandleMessage(myIdentityKey *ecdsa.PrivateKey, theirPu
 	protocolMessage := &ProtocolMessage{}
 
 	if err := proto.Unmarshal(payload, protocolMessage); err != nil {
-		return nil, err
+		return nil, ErrNotProtocolMessage
 	}
 
 	// Process bundle, deprecated, here for backward compatibility

services/shhext/chat/protocol_test.go

@@ -80,13 +80,12 @@ func (s *ProtocolServiceTestSuite) TestBuildDirectMessage() {
 	})
 	s.NoError(err)
 
-	marshaledMsg, err := s.alice.BuildDirectMessage(aliceKey, payload, &bobKey.PublicKey, &aliceKey.PublicKey)
+	marshaledMsg, err := s.alice.BuildDirectMessage(aliceKey, &bobKey.PublicKey, payload)
 	s.NoError(err)
 	s.NotNil(marshaledMsg, "It creates a message")
-	s.NotNil(marshaledMsg[&aliceKey.PublicKey], "It creates a single message")
 
 	unmarshaledMsg := &ProtocolMessage{}
-	err = proto.Unmarshal(marshaledMsg[&bobKey.PublicKey], unmarshaledMsg)
+	err = proto.Unmarshal(marshaledMsg, unmarshaledMsg)
 	s.NoError(err)
 	s.NotNilf(unmarshaledMsg.GetBundle(), "It adds a bundle to the message")
 
@@ -116,12 +115,12 @@ func (s *ProtocolServiceTestSuite) TestBuildAndReadDirectMessage() {
 	s.NoError(err)
 
 	// Message is sent with DH
-	marshaledMsg, err := s.alice.BuildDirectMessage(aliceKey, marshaledPayload, &bobKey.PublicKey)
+	marshaledMsg, err := s.alice.BuildDirectMessage(aliceKey, &bobKey.PublicKey, marshaledPayload)
 
 	s.NoError(err)
 
 	// Bob is able to decrypt the message
-	unmarshaledMsg, err := s.bob.HandleMessage(bobKey, &aliceKey.PublicKey, marshaledMsg[&bobKey.PublicKey])
+	unmarshaledMsg, err := s.bob.HandleMessage(bobKey, &aliceKey.PublicKey, marshaledMsg)
 	s.NoError(err)
 
 	s.NotNil(unmarshaledMsg)

services/shhext/chat/rpc.go

@@ -20,11 +20,5 @@ type SendDirectMessageRPC struct {
 	Chat    string
 	Payload hexutil.Bytes
 	PubKey  hexutil.Bytes
-}
+	DH      bool
-
-// SendGroupMessageRPC represents the RPC payload for the SendGroupMessage RPC method
-type SendGroupMessageRPC struct {
-	Sig     string
-	Payload hexutil.Bytes
-	PubKeys []hexutil.Bytes
 }

services/shhext/chat/sql_lite_persistence.go

@@ -983,11 +983,13 @@ func (s *SQLLitePersistence) AddInstallations(identity []byte, timestamp int64,
 			return err
 		}
 
-		// We update timestamp if present without changing enabled
+		// We update timestamp if present without changing enabled, only if this is a new bundle
 		if err != sql.ErrNoRows {
 			stmt, err = tx.Prepare(`UPDATE installations
 					        SET timestamp = ?,  enabled = ?
-						WHERE identity = ? AND installation_id = ?`)
+						WHERE identity = ?
+						AND installation_id = ?
+						AND timestamp < ?`)
 			if err != nil {
 				return err
 			}
@@ -997,6 +999,7 @@ func (s *SQLLitePersistence) AddInstallations(identity []byte, timestamp int64,
 				oldEnabled,
 				identity,
 				installationID,
+				timestamp,
 			)
 			if err != nil {
 				return err

services/shhext/service.go

@@ -204,6 +204,14 @@ func (s *Service) EnableInstallation(myIdentityKey *ecdsa.PublicKey, installatio
 	return s.protocol.EnableInstallation(myIdentityKey, installationID)
 }
 
+func (s *Service) GetPublicBundle(identityKey *ecdsa.PublicKey) (*chat.Bundle, error) {
+	if s.protocol == nil {
+		return nil, errProtocolNotInitialized
+	}
+
+	return s.protocol.GetPublicBundle(identityKey)
+}
+
 // DisableInstallation disables an installation for multi-device sync.
 func (s *Service) DisableInstallation(myIdentityKey *ecdsa.PublicKey, installationID string) error {
 	if s.protocol == nil {