Exemplo n.º 1
0
        /// <param name="ack1SdIsReady">
        /// =true for SD in ACK2
        /// =false for SD in ACK1 (since the SessionDescription is not initialized yet)
        /// </param>
        internal byte[] Encrypt(ICryptoLibrary cryptoLibrary, InviteRequestPacket req, InviteAck1Packet ack1, InviteSession session,
                                bool ack1SdIsReady
                                )
        {
            BinaryProcedures.CreateBinaryWriter(out var ms, out var w);
            w.Write(Flags);
            UserCertificate.Encode(w, false);
            BinaryProcedures.EncodeIPEndPoint(w, DirectChannelEndPoint);
            NatBehaviour.Encode(w);
            DirectChannelToken32.Encode(w);
            w.Write((byte)SessionType);
            UserCertificateSignature.Encode(w);
            var bytesInLastBlock = (int)ms.Position % CryptoLibraries.AesBlockSize;

            if (bytesInLastBlock != 0)
            {
                var bytesRemainingTillFullAesBlock = CryptoLibraries.AesBlockSize - bytesInLastBlock;
                w.Write(cryptoLibrary.GetRandomBytes(bytesRemainingTillFullAesBlock));
            }
            var plainTextSdData = ms.ToArray();
            var encryptedSdData = new byte[plainTextSdData.Length];

            #region key, iv
            BinaryProcedures.CreateBinaryWriter(out var ms2, out var w2);
            req.GetSharedSignedFields(w2);
            ack1.GetSharedSignedFields(w2, ack1SdIsReady);
            var iv = cryptoLibrary.GetHashSHA256(ms2.ToArray()).Take(16).ToArray();
            ms2.Write(session.SharedInviteAckDhSecret, 0, session.SharedInviteAckDhSecret.Length);
            var aesKey = cryptoLibrary.GetHashSHA256(ms2.ToArray()); // here SHA256 is used as KDF, together with common fields from packets, including both ECDH public keys and timestamp
            #endregion

            cryptoLibrary.ProcessAesCbcBlocks(true, aesKey, iv, plainTextSdData, encryptedSdData);

            return(encryptedSdData);
        }
Exemplo n.º 2
0
        /// <param name="receivedFromUser">comes from local contact book. is null if it is contact invitation</param>
        internal static InviteSessionDescription Decrypt_Verify(ICryptoLibrary cryptoLibrary, byte[] encryptedSdData,
                                                                InviteRequestPacket req,
                                                                InviteAck1Packet ack1,
                                                                bool ack1SdIsReady,
                                                                InviteSession session,
                                                                UserId receivedFromUserNullable,
                                                                DateTime localTimeNowUtc
                                                                )
        {
            #region key, iv
            BinaryProcedures.CreateBinaryWriter(out var ms2, out var w2);
            req.GetSharedSignedFields(w2);
            ack1.GetSharedSignedFields(w2, ack1SdIsReady);
            var iv = cryptoLibrary.GetHashSHA256(ms2.ToArray()).Take(16).ToArray();
            ms2.Write(session.SharedInviteAckDhSecret, 0, session.SharedInviteAckDhSecret.Length);
            var aesKey = cryptoLibrary.GetHashSHA256(ms2.ToArray()); // here SHA256 is used as KDF, together with common fields from packets, including both ECDH public keys and timestamp
            #endregion

            // decrypt
            var plainTextSdData = new byte[encryptedSdData.Length];
            cryptoLibrary.ProcessAesCbcBlocks(false, aesKey, iv, encryptedSdData, plainTextSdData);

            var r      = new InviteSessionDescription();
            var reader = BinaryProcedures.CreateBinaryReader(plainTextSdData, 0);
            r.Flags = reader.ReadByte();
            if ((r.Flags & FlagsMask_MustBeZero) != 0)
            {
                throw new NotImplementedException();
            }
            r.UserCertificate          = UserCertificate.Decode_AssertIsValidNow(reader, cryptoLibrary, receivedFromUserNullable, localTimeNowUtc);
            r.DirectChannelEndPoint    = BinaryProcedures.DecodeIPEndPoint(reader);
            r.NatBehaviour             = NatBehaviourModel.Decode(reader);
            r.DirectChannelToken32     = DirectChannelToken32.Decode(reader);
            r.SessionType              = (SessionType)reader.ReadByte();
            r.UserCertificateSignature = UserCertificateSignature.DecodeAndVerify(reader, cryptoLibrary,
                                                                                  w =>
            {
                req.GetSharedSignedFields(w);
                ack1.GetSharedSignedFields(w, ack1SdIsReady);
                r.WriteSignedFields(w);
            },
                                                                                  r.UserCertificate);
            return(r);
        }
Exemplo n.º 3
0
        internal void DeriveSharedPingPongHmacKey(InviteRequestPacket req, InviteAck1Packet ack1, InviteAck2Packet ack2, InviteConfirmationPacket cfm)
        {
            if (SharedInviteAckDhSecret == null)
            {
                throw new NotImplementedException();
            }

            PacketProcedures.CreateBinaryWriter(out var ms, out var w);
            req.GetSharedSignedFields(w);
            ack1.GetSharedSignedFields(w, true);
            ack2.GetSharedSignedFields(w);
            cfm.GetSharedSignedFields(w);
            w.Write(SharedInviteAckDhSecret);

            SharedPingPongHmacKey = _localDrpPeer.CryptoLibrary.GetHashSHA256(ms.ToArray());
        }
Exemplo n.º 4
0
        /// <summary>
        /// sends INVITE, autenticates users, returns Session to be used to create direct cannel
        /// </summary>
        /// <param name="responderUserId">
        /// comes from local contact book
        /// </param>
        /// <param name="responderRegId">
        /// comes from local contact book
        /// </param>
        /// <param name="loggerCb">may be invoked more than one time (in case of retrying)</param>
        public async Task <InviteSession> SendInviteAsync(UserCertificate requesterUserCertificate, RegistrationId responderRegistrationId, UserId responderUserId,
                                                          SessionType sessionType, Action <Logger> loggerCb = null)
        {
            InviteSession session = null;

            try
            {
                var           sw            = Stopwatch.StartNew();
                RoutedRequest routedRequest = null;
                int           trialsCount   = 0;
                Exception     latestTriedNeighborException = null;


_retry:
                trialsCount++;
                session = new InviteSession(this);
                var req = new InviteRequestPacket
                {
                    NumberOfHopsRemaining   = InviteRequestPacket.MaxNumberOfHopsRemaining,
                    RequesterEcdhePublicKey = new EcdhPublicKey(session.LocalInviteAckEcdhePublicKey),
                    RequesterRegistrationId = this.Configuration.LocalPeerRegistrationId,
                    ResponderRegistrationId = responderRegistrationId,
                    ReqTimestamp32S         = Engine.Timestamp32S,
                };
                var logger = new Logger(Engine, this, req, DrpPeerEngine.VisionChannelModuleName_inv_requesterSide);
                if (!Engine.RecentUniqueInviteRequests.Filter(req.GetUniqueRequestIdFields))
                {
                    if (trialsCount > 50)
                    {
                        throw new NonUniquePacketFieldsException($"could not find unique fields to send INVITE request");
                    }
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"waiting a second to generate ne wunique INVITE request");
                    }
                    await Engine.EngineThreadQueue.WaitAsync(TimeSpan.FromSeconds(1), "inv_wait_1236");

                    goto _retry;
                }


                session.Logger = logger;
                loggerCb?.Invoke(logger);
                Engine.RecentUniquePublicEcdhKeys.AssertIsUnique(req.RequesterEcdhePublicKey.Ecdh25519PublicKey, "req.RequesterEcdhePublicKey");
                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"generated unique ECDH key {req.RequesterEcdhePublicKey}");
                }
                req.RequesterRegistrationSignature = RegistrationSignature.Sign(Engine.CryptoLibrary, req.GetSharedSignedFields, this.Configuration.LocalPeerRegistrationPrivateKey);

                this.TestDirection(logger, req.ResponderRegistrationId);
                routedRequest = new RoutedRequest(logger, null, null, null, req, null, routedRequest);

                // find best connected peer to send the request
                var destinationPeer = Engine.RouteInviteRequest(this, routedRequest);
                if (destinationPeer == null)
                {
                    if (latestTriedNeighborException == null)
                    {
                        throw new NoNeighborsToSendInviteException();
                    }
                    else
                    {
                        throw latestTriedNeighborException;
                    }
                }
                InviteAck1Packet ack1;
                try
                {
                    var reqUdpData = req.Encode_SetP2pFields(destinationPeer);
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"sending {req} (ReqTimestamp32S={MiscProcedures.Uint32secondsToDateTime(req.ReqTimestamp32S)}), waiting for NPACK");
                    }

                    var sentRequest = new SentRequest(Engine, logger, destinationPeer.RemoteEndpoint, destinationPeer, reqUdpData, req.ReqP2pSeq16, InviteAck1Packet.GetScanner(logger, req, destinationPeer));
                    var ack1UdpData = await sentRequest.SendRequestAsync("ack1 4146");

                    #region process ACK1
                    // NeighborHMAC and NeighborToken32 are already verified by scanner
                    ack1 = InviteAck1Packet.Decode(ack1UdpData);
                    Engine.RecentUniquePublicEcdhKeys.AssertIsUnique(ack1.ResponderEcdhePublicKey.Ecdh25519PublicKey, $"ack1.ResponderEcdhePublicKey");
                    if (!ack1.ResponderRegistrationSignature.Verify(Engine.CryptoLibrary, w =>
                    {
                        req.GetSharedSignedFields(w);
                        ack1.GetSharedSignedFields(w, true);
                    },
                                                                    responderRegistrationId))
                    {
                        throw new BadSignatureException("invalid REGISTER ACK1 ResponderRegistrationSignature 2349");
                    }
                    if (logger.WriteToLog_detail_enabled)
                    {
                        logger.WriteToLog_detail($"verified ACK1");
                    }
                    session.DeriveSharedInviteAckDhSecret(Engine.CryptoLibrary, ack1.ResponderEcdhePublicKey.Ecdh25519PublicKey);

                    // send NPACK to ACK1
                    SendNeighborPeerAckResponseToAck1(ack1, destinationPeer);
                    #endregion
                }
                catch (RequestFailedException exc2)
                {
                    latestTriedNeighborException = exc2;
                    if (trialsCount > 50)
                    {
                        throw;
                    }
                    logger.WriteToLog_higherLevelDetail($"trying again on error {exc2.Message}... alreadyTriedProxyingToDestinationPeers.Count={routedRequest.TriedNeighbors.Count}");
                    routedRequest.TriedNeighbors.Add(destinationPeer);
                    goto _retry;
                }

                // decode and verify SD
                session.RemoteSessionDescription = InviteSessionDescription.Decrypt_Verify(Engine.CryptoLibrary,
                                                                                           ack1.ToResponderSessionDescriptionEncrypted,
                                                                                           req, ack1, false, session,
                                                                                           responderUserId, Engine.DateTimeNowUtc);

                // sign and encode local SD
                session.LocalSessionDescription = new InviteSessionDescription
                {
                    DirectChannelEndPoint = destinationPeer.LocalEndpoint,
                    SessionType           = sessionType,
                    DirectChannelToken32  = session.LocalDirectChannelToken32
                };

                session.LocalSessionDescription.UserCertificate = requesterUserCertificate;

                session.LocalSessionDescription.UserCertificateSignature = UserCertificateSignature.Sign(Engine.CryptoLibrary,
                                                                                                         w =>
                {
                    req.GetSharedSignedFields(w);
                    ack1.GetSharedSignedFields(w, true);
                    session.LocalSessionDescription.WriteSignedFields(w);
                },
                                                                                                         requesterUserCertificate
                                                                                                         );

                #region send ack2
                var ack2 = new InviteAck2Packet
                {
                    RequesterRegistrationId = req.RequesterRegistrationId,
                    ResponderRegistrationId = req.ResponderRegistrationId,
                    ReqTimestamp32S         = req.ReqTimestamp32S,
                    ToRequesterSessionDescriptionEncrypted = session.LocalSessionDescription.Encrypt(Engine.CryptoLibrary, req, ack1, session, true)
                };
                ack2.RequesterRegistrationSignature = RegistrationSignature.Sign(Engine.CryptoLibrary, w =>
                {
                    req.GetSharedSignedFields(w);
                    ack1.GetSharedSignedFields(w, true);
                    ack2.GetSharedSignedFields(w);
                }, this.Configuration.LocalPeerRegistrationPrivateKey);
                var ack2UdpData = ack2.Encode_SetP2pFields(destinationPeer);

                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"sending ACK2, waiting for NPACK");
                }
                await destinationPeer.SendUdpRequestAsync_Retransmit_WaitForNPACK("ack2 234575672", ack2UdpData, ack2.ReqP2pSeq16, ack2.GetSignedFieldsForNeighborHMAC);

                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"received NPACK");
                }
                #endregion

                #region wait for CFM
                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"waiting for CFM");
                }
                var cfmUdpData = await Engine.WaitForUdpResponseAsync(new PendingLowLevelUdpRequest("cfm 1235695", destinationPeer.RemoteEndpoint,
                                                                                                    InviteConfirmationPacket.GetScanner(logger, req, destinationPeer),
                                                                                                    Engine.DateTimeNowUtc, Engine.Configuration.CfmTimoutS
                                                                                                    ));

                if (cfmUdpData == null)
                {
                    throw new DrpTimeoutException($"did not get CFM at invite requester from destination peer {destinationPeer} (timeout={Engine.Configuration.CfmTimoutS}s)");
                }

                // NeighborHMAC and NeighborToken32 are already verified by scanner
                var cfm = InviteConfirmationPacket.Decode(cfmUdpData);

                if (!cfm.ResponderRegistrationSignature.Verify(Engine.CryptoLibrary, w =>
                {
                    req.GetSharedSignedFields(w);
                    ack1.GetSharedSignedFields(w, true);
                    ack2.GetSharedSignedFields(w);
                },
                                                               responderRegistrationId))
                {
                    throw new BadSignatureException("invalid REGISTER CFM ResponderRegistrationSignature 6398");
                }

                if (logger.WriteToLog_detail_enabled)
                {
                    logger.WriteToLog_detail($"verified CFM");
                }

                // send NPACK to CFM
                SendNeighborPeerAckResponseToCfm(cfm, destinationPeer);
                #endregion

                session.DeriveSharedPingPongHmacKey(req, ack1, ack2, cfm);
                return(session);
            }
            catch
            {
                session?.Dispose();
                throw;
            }
        }