Example #1
0
        public void handle(SignalServiceEnvelope envelope, bool sendExplicitReceipt)
        {
            if (!isActiveNumber(envelope.getSource()))
            {
                TextSecureDirectory directory           = DatabaseFactory.getDirectoryDatabase();
                ContactTokenDetails contactTokenDetails = new ContactTokenDetails();
                contactTokenDetails.setNumber(envelope.getSource());

                directory.setNumber(contactTokenDetails, true);

                // TODO: evtl DirectoryRefresh
            }

            if (envelope.isReceipt())
            {
                handleReceipt(envelope);
            }
            else if (envelope.isPreKeySignalMessage() || envelope.isSignalMessage())
            {
                handleMessage(envelope, sendExplicitReceipt);
            }
            else
            {
                Log.Warn($"Received envelope of unknown type: {envelope.GetType()}");
            }
        }
        /// <summary>
        ///
        /// </summary>
        /// <param name="envelope"></param>
        /// <param name="ciphertext"></param>
        /// <returns></returns>
        /// <exception cref="InvalidMetadataMessageException"></exception>
        /// <exception cref="InvalidMetadataVersionException"></exception>
        /// <exception cref="ProtocolDuplicateMessageException"></exception>
        /// <exception cref="ProtocolUntrustedIdentityException"></exception>
        /// <exception cref="ProtocolLegacyMessageException"></exception>
        /// <exception cref="ProtocolInvalidKeyException"></exception>
        /// <exception cref="ProtocolInvalidVersionException"></exception>
        /// <exception cref="ProtocolInvalidMessageException"></exception>
        /// <exception cref="ProtocolInvalidKeyIdException"></exception>
        /// <exception cref="ProtocolNoSessionException"></exception>
        /// <exception cref="SelfSendException"></exception>
        private Plaintext Decrypt(SignalServiceEnvelope envelope, byte[] ciphertext)
        {
            try
            {
                byte[] paddedMessage;
                SignalServiceMetadata metadata;
                uint sessionVersion;

                if (!envelope.HasSource() && !envelope.IsUnidentifiedSender())
                {
                    throw new ProtocolInvalidMessageException(new InvalidMessageException("Non-UD envelope is missing a source!"), null, 0);
                }

                if (envelope.IsPreKeySignalMessage())
                {
                    SignalProtocolAddress sourceAddress = GetPreferredProtocolAddress(signalProtocolStore, envelope.GetSourceAddress(), envelope.GetSourceDevice());
                    SessionCipher         sessionCipher = new SessionCipher(signalProtocolStore, sourceAddress);

                    paddedMessage  = sessionCipher.decrypt(new PreKeySignalMessage(ciphertext));
                    metadata       = new SignalServiceMetadata(envelope.GetSourceAddress(), envelope.GetSourceDevice(), envelope.GetTimestamp(), false);
                    sessionVersion = sessionCipher.getSessionVersion();
                }
                else if (envelope.IsSignalMessage())
                {
                    SignalProtocolAddress sourceAddress = GetPreferredProtocolAddress(signalProtocolStore, envelope.GetSourceAddress(), envelope.GetSourceDevice());
                    SessionCipher         sessionCipher = new SessionCipher(signalProtocolStore, sourceAddress);

                    paddedMessage  = sessionCipher.decrypt(new SignalMessage(ciphertext));
                    metadata       = new SignalServiceMetadata(envelope.GetSourceAddress(), envelope.GetSourceDevice(), envelope.GetTimestamp(), false);
                    sessionVersion = sessionCipher.getSessionVersion();
                }
                else if (envelope.IsUnidentifiedSender())
                {
                    SealedSessionCipher   sealedSessionCipher = new SealedSessionCipher(signalProtocolStore, localAddress.Uuid, localAddress.GetNumber(), 1);
                    DecryptionResult      result          = sealedSessionCipher.Decrypt(certificateValidator !, ciphertext, (long)envelope.Envelope.ServerTimestamp);
                    SignalServiceAddress  resultAddress   = new SignalServiceAddress(UuidUtil.Parse(result.SenderUuid), result.SenderE164);
                    SignalProtocolAddress protocolAddress = GetPreferredProtocolAddress(signalProtocolStore, resultAddress, result.DeviceId);

                    paddedMessage  = result.PaddedMessage;
                    metadata       = new SignalServiceMetadata(resultAddress, result.DeviceId, envelope.GetTimestamp(), true);
                    sessionVersion = (uint)sealedSessionCipher.GetSessionVersion(protocolAddress);
                }
                else
                {
                    throw new InvalidMessageException($"Unknown type: {envelope.GetType()}");
                }

                PushTransportDetails transportDetails = new PushTransportDetails(sessionVersion);
                byte[] data = transportDetails.GetStrippedPaddingMessageBody(paddedMessage);

                return(new Plaintext(metadata, data));
            }
            catch (DuplicateMessageException e)
            {
                throw new ProtocolDuplicateMessageException(e, envelope.GetSourceIdentifier(), envelope.GetSourceDevice());
            }
            catch (LegacyMessageException e)
            {
                throw new ProtocolLegacyMessageException(e, envelope.GetSourceIdentifier(), envelope.GetSourceDevice());
            }
            catch (InvalidMessageException e)
            {
                throw new ProtocolInvalidMessageException(e, envelope.GetSourceIdentifier(), envelope.GetSourceDevice());
            }
            catch (InvalidKeyIdException e)
            {
                throw new ProtocolInvalidKeyIdException(e, envelope.GetSourceIdentifier(), envelope.GetSourceDevice());
            }
            catch (InvalidKeyException e)
            {
                throw new ProtocolInvalidKeyException(e, envelope.GetSourceIdentifier(), envelope.GetSourceDevice());
            }
            catch (libsignal.exceptions.UntrustedIdentityException e)
            {
                throw new ProtocolUntrustedIdentityException(e, envelope.GetSourceIdentifier(), envelope.GetSourceDevice());
            }
            catch (InvalidVersionException e)
            {
                throw new ProtocolInvalidVersionException(e, envelope.GetSourceIdentifier(), envelope.GetSourceDevice());
            }
            catch (NoSessionException e)
            {
                throw new ProtocolNoSessionException(e, envelope.GetSourceIdentifier(), envelope.GetSourceDevice());
            }
        }