/// <summary>
/// Initializes a new instance of the <see cref="ClientMsgProtobuf"/> class.
/// This is a recieve constructor.
/// </summary>
/// <param name="msg">The packet message to build this client message from.</param>
public ClientMsgProtobuf(IPacketMsg msg)
: this(msg.MsgType)
{
DebugLog.Assert(msg.IsProto, "ClientMsgProtobuf", "ClientMsgProtobuf used for non-proto message!");
Deserialize(msg.GetData());
}
/// <summary>
/// Downloads the specified depot chunk, and optionally processes the chunk and verifies the checksum if the depot decryption key has been provided.
/// </summary>
/// <remarks>
/// This function will also validate the length of the downloaded chunk with the value of <see cref="DepotManifest.ChunkData.CompressedLength"/>,
/// if it has been assigned a value.
/// </remarks>
/// <param name="chunk">
/// A <see cref="DepotManifest.ChunkData"/> instance that represents the chunk to download.
/// This value should come from a manifest downloaded with <see cref="CDNClient.DownloadManifest"/>.
/// </param>
/// <returns>A <see cref="DepotChunk"/> instance that contains the data for the given chunk.</returns>
/// <exception cref="System.ArgumentNullException">chunk's <see cref="DepotManifest.ChunkData.ChunkID"/> was null.</exception>
public DepotChunk DownloadDepotChunk(DepotManifest.ChunkData chunk)
{
if (chunk.ChunkID == null)
{
throw new ArgumentNullException("chunk.ChunkID");
}
string chunkId = Utils.EncodeHexString(chunk.ChunkID);
byte[] chunkData = DoRawCommand(connectedServer, "depot", doAuth: true, args: string.Format("{0}/chunk/{1}", depotId, chunkId));
if (chunk.CompressedLength != default(uint))
{
// assert that lengths match only if the chunk has a length assigned.
DebugLog.Assert(chunkData.Length == chunk.CompressedLength, "CDNClient", "Length mismatch after downloading depot chunk!");
}
var depotChunk = new DepotChunk
{
ChunkInfo = chunk,
Data = chunkData,
};
if (depotKey != null)
{
// if we have the depot key, we can process the chunk immediately
depotChunk.Process(depotKey);
}
return(depotChunk);
}
/// <summary>
/// Dispatches up to one message to the rest of SteamKit
/// </summary>
/// <returns>True if a message was dispatched, false otherwise</returns>
private bool DispatchMessage()
{
uint numPackets = ReadyMessageParts();
if (numPackets == 0)
{
return(false);
}
MemoryStream payload = new MemoryStream();
for (uint i = 0; i < numPackets; i++)
{
var handled = inPackets.TryGetValue(++inSeqHandled, out var packet);
DebugLog.Assert(handled, nameof(UdpConnection), "Should have retrieved next packet info.");
inPackets.Remove(inSeqHandled);
packet !.Payload.WriteTo(payload);
}
byte[] data = payload.ToArray();
log.LogDebug("UdpConnection", "Dispatching message; {0} bytes", data.Length);
NetMsgReceived?.Invoke(this, new NetMsgEventArgs(data, CurrentEndPoint !));
return(true);
}
/// <summary>
/// Decrypts using AES/ECB/PKCS7
/// </summary>
public static byte[] SymmetricDecryptECB(byte[] input, byte[] key)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
DebugLog.Assert(key.Length == 32, "CryptoHelper", "SymmetricDecryptECB used with non 32 byte key!");
using (var aes = Aes.Create())
{
aes.BlockSize = 128;
aes.KeySize = 256;
aes.Mode = CipherMode.ECB;
aes.Padding = PaddingMode.PKCS7;
using (var aesTransform = aes.CreateDecryptor(key, null))
{
byte[] output = aesTransform.TransformFinalBlock(input, 0, input.Length);
return(output);
}
}
}
private void TryConnect(int timeout)
{
DebugLog.Assert(cancellationToken != null, nameof(TcpConnection), "null CancellationToken in TryConnect");
if (cancellationToken.IsCancellationRequested)
{
log.LogDebug(nameof(TcpConnection), "Connection to {0} cancelled by user", CurrentEndPoint);
Release(userRequestedDisconnect: true);
return;
}
DebugLog.Assert(socket != null, nameof(TcpConnection), "socket should not be null when connecting (we hold the net lock)");
DebugLog.Assert(CurrentEndPoint != null, nameof(TcpConnection), "CurrentEndPoint should be non-null when connecting.");
try
{
using var timeoutTokenSource = new CancellationTokenSource(timeout);
using var connectCancellation = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken.Token, timeoutTokenSource.Token);
using (connectCancellation.Token.Register(s => (( Socket )s !).Dispose(), socket))
{
socket.Connect(CurrentEndPoint);
}
}
catch (SocketException) when(cancellationToken.IsCancellationRequested)
{
// Ignore, this will be handled by ConnectCompleted.
}
catch (Exception ex)
{
log.LogDebug(nameof(TcpConnection), "Exception while connecting to {0}: {1}", CurrentEndPoint, ex);
}
ConnectCompleted(socket.Connected);
}
/// <summary>
/// Initializes a new instance of the <see cref="ClientMsg<BodyType>"/> class.
/// This is a recieve constructor.
/// </summary>
/// <param name="msg">The packet message to build this client message from.</param>
public ClientMsg(IPacketMsg msg)
: this()
{
DebugLog.Assert(!msg.IsProto, "ClientMsg", $"ClientMsg<{typeof(BodyType).FullName}> used for proto message!");
Deserialize(msg.GetData());
}
async Task <DepotChunk> DownloadDepotChunkCoreAsync(uint depotId, DepotManifest.ChunkData chunk, Server server, string cdnAuthToken, byte[] depotKey)
{
var chunkID = Utils.EncodeHexString(chunk.ChunkID);
var chunkData = await DoRawCommandAsync(server, HttpMethod.Get, "depot", doAuth : true, args : string.Format("{0}/chunk/{1}", depotId, chunkID), authtoken : cdnAuthToken).ConfigureAwait(false);
if (chunk.CompressedLength != default(uint))
{
// assert that lengths match only if the chunk has a length assigned.
DebugLog.Assert(chunkData.Length == chunk.CompressedLength, "CDNClient", "Length mismatch after downloading depot chunk!");
}
var depotChunk = new DepotChunk
{
ChunkInfo = chunk,
Data = chunkData,
};
if (depotKey != null)
{
// if we have the depot key, we can process the chunk immediately
depotChunk.Process(depotKey);
}
return(depotChunk);
}
public NetFilterEncryption(byte[] sessionKey, ILogContext log)
{
DebugLog.Assert(sessionKey.Length == 32, nameof(NetFilterEncryption), "AES session key was not 32 bytes!");
this.sessionKey = sessionKey;
this.log = log ?? throw new ArgumentNullException(nameof(log));
}
private void TryConnect(object sender)
{
DebugLog.Assert(cancellationToken != null, nameof(TcpConnection), "null CancellationToken in TryConnect");
int timeout = (int)sender;
if (cancellationToken.IsCancellationRequested)
{
log.LogDebug("TcpConnection", "Connection to {0} cancelled by user", CurrentEndPoint);
Release(userRequestedDisconnect: true);
return;
}
var asyncResult = socket !.BeginConnect(CurrentEndPoint, null, null);
if (WaitHandle.WaitAny(new WaitHandle[] { asyncResult.AsyncWaitHandle, cancellationToken.Token.WaitHandle }, timeout) == 0)
{
try
{
socket.EndConnect(asyncResult);
ConnectCompleted(true);
}
catch (Exception ex)
{
log.LogDebug("TcpConnection", "Socket exception while completing connection request to {0}: {1}", CurrentEndPoint, ex);
ConnectCompleted(false);
}
}
else
{
ConnectCompleted(false);
}
}
/// <summary>
/// Connects this client to a UFS server.
/// This begins the process of connecting and encrypting the data channel between the client and the UFS server.
/// Results are returned asynchronously in a <see cref="ConnectedCallback"/>.
/// If the UFS server that this client attempts to connect to is down, a <see cref="DisconnectedCallback"/> will be posted instead.
/// <see cref="UFSClient"/> will not attempt to reconnect to Steam, you must handle this callback and call <see cref="Connect"/> again, preferrably after a short delay.
/// In order to connect to the UFS server, the parent <see cref="SteamClient"/> must be connected to the CM server.
/// </summary>
/// <param name="ufsServer">
/// The <see cref="System.Net.IPEndPoint"/> of the UFS server to connect to.
/// If <c>null</c>, <see cref="UFSClient"/> will randomly select a UFS server from the <see cref="SteamClient"/>'s list of servers.
/// </param>
public void Connect(IPEndPoint ufsServer = null)
{
DebugLog.Assert(steamClient.IsConnected, nameof(UFSClient), "CMClient is not connected!");
Disconnect();
Debug.Assert(connection == null);
if (ufsServer == null)
{
var serverList = steamClient.GetServersOfType(EServerType.UFS);
if (serverList.Count == 0)
{
DebugLog.WriteLine(nameof(UFSClient), "No UFS server addresses were provided yet.");
Disconnected(this, new DisconnectedEventArgs(userInitiated: false));
return;
}
var random = new Random();
ufsServer = serverList[random.Next(serverList.Count)];
}
// steamclient has the connection type hardcoded as TCP
// todo: determine if UFS supports UDP and if we want to support it
connection = new EnvelopeEncryptedConnection(new TcpConnection(), steamClient.Universe);
connection.NetMsgReceived += NetMsgReceived;
connection.Connected += Connected;
connection.Disconnected += Disconnected;
connection.Connect(ufsServer, ( int )ConnectionTimeout.TotalMilliseconds);
}
/// <summary>
/// Initializes a new instance of the <see cref="JobCallback<T>"/> class.
/// </summary>
/// <param name="jobId">The for this callback.</param>
/// <param name="callback">The inner callback object.</param>
public JobCallback(JobID jobId, T callback)
: base(jobId)
{
DebugLog.Assert(jobId != ulong.MaxValue, "JobCallback", "JobCallback used for non job based callback!");
Callback = callback;
}
public static byte[]? GetMachineID(IMachineInfoProvider machineInfoProvider)
{
if (!generationTable.TryGetValue(machineInfoProvider, out var generateTask))
{
DebugLog.WriteLine(nameof(HardwareUtils), "GetMachineID() called before Init()");
return(null);
}
DebugLog.Assert(generateTask != null, nameof(HardwareUtils), "GetMachineID() found null task - should be impossible.");
try
{
bool didComplete = generateTask.Wait(TimeSpan.FromSeconds(30));
if (!didComplete)
{
DebugLog.WriteLine(nameof(HardwareUtils), "Unable to generate machine_id in a timely fashion, logons may fail");
return(null);
}
}
catch (AggregateException ex) when(ex.InnerException != null && generateTask.IsFaulted)
{
// Rethrow the original exception rather than a wrapped AggregateException.
ExceptionDispatchInfo.Capture(ex.InnerException).Throw();
}
MachineID machineId = generateTask.Result;
using MemoryStream ms = new MemoryStream();
machineId.WriteToStream(ms);
return(ms.ToArray());
}
/// <summary>
/// Attempts to decrypts file names with the given encryption key.
/// </summary>
/// <param name="encryptionKey">The encryption key.</param>
/// <returns><c>true</c> if the file names were successfully decrypted; otherwise, <c>false</c>.</returns>
public bool DecryptFilenames(byte[] encryptionKey)
{
if (!FilenamesEncrypted)
{
return(true);
}
DebugLog.Assert(Files != null, nameof(DepotManifest), "Files was null when attempting to decrypt filenames.");
foreach (var file in Files)
{
byte[] enc_filename = Convert.FromBase64String(file.FileName);
byte[] filename;
try
{
filename = CryptoHelper.SymmetricDecrypt(enc_filename, encryptionKey);
}
catch (Exception)
{
return(false);
}
file.FileName = Encoding.UTF8.GetString(filename).TrimEnd(new char[] { '\0' }).Replace(altDirChar, Path.DirectorySeparatorChar);
}
FilenamesEncrypted = false;
return(true);
}
/// <summary>
/// Initializes a new instance of the <see cref="ClientMsg<BodyType>"/> class.
/// This is a recieve constructor.
/// </summary>
/// <param name="msg">The packet message to build this client message from.</param>
public ClientMsg(IPacketMsg msg)
: this()
{
DebugLog.Assert(!msg.IsProto, "ClientMsg", "ClientMsg used for proto message!");
Deserialize(msg.GetData());
}
// this is now a steamkit meme
/// <summary>
/// Nets the loop.
/// </summary>
void NetLoop()
{
// poll for readable data every 100ms
const int POLL_MS = 100;
DebugLog.Assert(cancellationToken != null, nameof(TcpConnection), "null cancellationToken in NetLoop");
while (!cancellationToken.IsCancellationRequested)
{
bool canRead = false;
try
{
canRead = socket !.Poll(POLL_MS * 1000, SelectMode.SelectRead);
}
catch (SocketException ex)
{
log.LogDebug(nameof(TcpConnection), "Socket exception while polling: {0}", ex);
break;
}
if (!canRead)
{
// nothing to read yet
continue;
}
byte[] packData;
try
{
// read the packet off the network
packData = ReadPacket();
}
catch (IOException ex)
{
log.LogDebug(nameof(TcpConnection), "Socket exception occurred while reading packet: {0}", ex);
break;
}
try
{
NetMsgReceived?.Invoke(this, new NetMsgEventArgs(packData, CurrentEndPoint !));
}
catch (Exception ex)
{
log.LogDebug(nameof(TcpConnection), "Unexpected exception propogated back to NetLoop: {0}", ex);
}
}
// Thread is shutting down, ensure socket is shut down and disposed
bool userShutdown = cancellationToken.IsCancellationRequested;
if (userShutdown)
{
Shutdown();
}
Release(userShutdown);
}
public NetFilterEncryptionWithHMAC(byte[] sessionKey)
{
DebugLog.Assert(sessionKey.Length == 32, nameof(NetFilterEncryption), "AES session key was not 32 bytes!");
this.sessionKey = sessionKey;
this.hmacSecret = new byte[16];
Array.Copy(sessionKey, 0, hmacSecret, 0, hmacSecret.Length);
}
/// <summary>
/// Performs an encryption using AES/CBC/PKCS7 with an input byte array and key, with a random IV prepended using AES/ECB/None
/// </summary>
public static byte[] SymmetricEncryptWithIV(byte[] input, byte[] key, byte[] iv)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
if (iv == null)
{
throw new ArgumentNullException(nameof(iv));
}
DebugLog.Assert(key.Length == 32, "CryptoHelper", "SymmetricEncrypt used with non 32 byte key!");
using (var aes = Aes.Create())
{
aes.BlockSize = 128;
aes.KeySize = 256;
byte[] cryptedIv;
// encrypt iv using ECB and provided key
aes.Mode = CipherMode.ECB;
aes.Padding = PaddingMode.None;
using (var aesTransform = aes.CreateEncryptor(key, null))
{
cryptedIv = aesTransform.TransformFinalBlock(iv, 0, iv.Length);
}
// encrypt input plaintext with CBC using the generated (plaintext) IV and the provided key
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
using (var aesTransform = aes.CreateEncryptor(key, iv))
using (var ms = new MemoryStream())
using (var cs = new CryptoStream(ms, aesTransform, CryptoStreamMode.Write))
{
cs.Write(input, 0, input.Length);
cs.FlushFinalBlock();
var cipherText = ms.ToArray();
// final output is 16 byte ecb crypted IV + cbc crypted plaintext
var output = new byte[cryptedIv.Length + cipherText.Length];
Array.Copy(cryptedIv, 0, output, 0, cryptedIv.Length);
Array.Copy(cipherText, 0, output, cryptedIv.Length, cipherText.Length);
return(output);
}
}
}
/// <summary>
/// Decrypts using AES/CBC/PKCS7 with an input byte array and key, using the random IV prepended using AES/ECB/None
/// </summary>
static byte[] SymmetricDecrypt(byte[] input, byte[] key, out byte[] iv)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
DebugLog.Assert(key.Length == 32, "CryptoHelper", "SymmetricDecrypt used with non 32 byte key!");
using (var aes = Aes.Create())
{
aes.BlockSize = 128;
aes.KeySize = 256;
// first 16 bytes of input is the ECB encrypted IV
byte[] cryptedIv = new byte[16];
iv = new byte[cryptedIv.Length];
Array.Copy(input, 0, cryptedIv, 0, cryptedIv.Length);
// the rest is ciphertext
byte[] cipherText = new byte[input.Length - cryptedIv.Length];
Array.Copy(input, cryptedIv.Length, cipherText, 0, cipherText.Length);
// decrypt the IV using ECB
aes.Mode = CipherMode.ECB;
aes.Padding = PaddingMode.None;
using (var aesTransform = aes.CreateDecryptor(key, null))
{
iv = aesTransform.TransformFinalBlock(cryptedIv, 0, cryptedIv.Length);
}
// decrypt the remaining ciphertext in cbc with the decrypted IV
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
using (var aesTransform = aes.CreateDecryptor(key, iv))
using (var ms = new MemoryStream(cipherText))
using (var cs = new CryptoStream(ms, aesTransform, CryptoStreamMode.Read))
{
// plaintext is never longer than ciphertext
byte[] plaintext = new byte[cipherText.Length];
int len = cs.ReadAll(plaintext);
byte[] output = new byte[len];
Array.Copy(plaintext, 0, output, 0, len);
return(output);
}
}
}
public NetFilterEncryptionWithHMAC(byte[] sessionKey, ILogContext log)
{
DebugLog.Assert(sessionKey.Length == 32, nameof(NetFilterEncryption), "AES session key was not 32 bytes!");
this.sessionKey = sessionKey;
this.log = log ?? throw new ArgumentNullException(nameof(log));
this.hmacSecret = new byte[16];
Array.Copy(sessionKey, 0, hmacSecret, 0, hmacSecret.Length);
}
/// <summary>
/// Connects and authenticates to the specified content server.
/// </summary>
/// <param name="csServer">The content server to connect to.</param>
/// <exception cref="System.ArgumentNullException">csServer was null.</exception>
public void Connect(Server csServer)
{
DebugLog.Assert(steamClient.IsConnected, "CDNClient", "CMClient is not connected!");
if (csServer == null)
{
throw new ArgumentNullException("csServer");
}
byte[] pubKey = KeyDictionary.GetPublicKey(steamClient.ConnectedUniverse);
sessionKey = CryptoHelper.GenerateRandomBlock(32);
byte[] cryptedSessKey = null;
using (var rsa = new RSACrypto(pubKey))
{
cryptedSessKey = rsa.Encrypt(sessionKey);
}
string data;
if (appTicket == null)
{
// no appticket, doing anonymous connection
data = string.Format("sessionkey={0}&anonymoususer=1&steamid={1}", WebHelpers.UrlEncode(cryptedSessKey), steamClient.SteamID.ConvertToUInt64());
}
else
{
byte[] encryptedAppTicket = CryptoHelper.SymmetricEncrypt(appTicket, sessionKey);
data = string.Format("sessionkey={0}&appticket={1}", WebHelpers.UrlEncode(cryptedSessKey), WebHelpers.UrlEncode(encryptedAppTicket));
}
KeyValue initKv = DoCommand(csServer, "initsession", data, WebRequestMethods.Http.Post);
sessionId = ( ulong )initKv["sessionid"].AsLong();
reqCounter = initKv["req-counter"].AsLong();
if (appTicket == null)
{
data = string.Format("depotid={0}", depotId);
}
else
{
byte[] encryptedAppTicket = CryptoHelper.SymmetricEncrypt(appTicket, sessionKey);
data = string.Format("appticket={0}", WebHelpers.UrlEncode(encryptedAppTicket));
}
DoCommand(csServer, "authdepot", data, WebRequestMethods.Http.Post, true);
connectedServer = csServer;
}
private void ConnectCompleted(bool success)
{
// Always discard result if our request was cancelled
// If we have no cancellation token source, we were already Release()'ed
if (cancellationToken?.IsCancellationRequested ?? true)
{
log.LogDebug(nameof(TcpConnection), "Connection request to {0} was cancelled", CurrentEndPoint);
if (success)
{
Shutdown();
}
Release(userRequestedDisconnect: true);
return;
}
else if (!success)
{
log.LogDebug(nameof(TcpConnection), "Failed connecting to {0}", CurrentEndPoint);
Release(userRequestedDisconnect: false);
return;
}
log.LogDebug(nameof(TcpConnection), "Connected to {0}", CurrentEndPoint);
DebugLog.Assert(socket != null, nameof(TcpConnection), "Socket should be non-null after connecting.");
try
{
lock (netLock)
{
netStream = new NetworkStream(socket, false);
netReader = new BinaryReader(netStream);
netWriter = new BinaryWriter(netStream);
netThread = new Thread(NetLoop)
{
Name = "SK2-TcpConn"
};
CurrentEndPoint = socket !.RemoteEndPoint;
}
netThread.Start();
Connected?.Invoke(this, EventArgs.Empty);
}
catch (Exception ex)
{
log.LogDebug(nameof(TcpConnection), "Exception while setting up connection to {0}: {1}", CurrentEndPoint, ex);
Release(userRequestedDisconnect: false);
}
}
/// <summary>
/// Connects to the specified end point.
/// </summary>
/// <param name="endPoint">The end point to connect to.</param>
/// <param name="timeout">Timeout in milliseconds</param>
public void Connect(EndPoint endPoint, int timeout)
{
lock ( netLock )
{
DebugLog.Assert(cancellationToken == null, nameof(TcpConnection), "Connection cancellation token is not null");
cancellationToken = new CancellationTokenSource();
socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socket.ReceiveTimeout = timeout;
socket.SendTimeout = timeout;
CurrentEndPoint = endPoint;
log.LogDebug(nameof(TcpConnection), "Connecting to {0}...", CurrentEndPoint);
TryConnect(timeout);
}
}
/// <summary>
/// Connects this client to a UFS server.
/// This begins the process of connecting and encrypting the data channel between the client and the UFS server.
/// Results are returned asynchronously in a <see cref="ConnectedCallback"/>.
/// If the UFS server that this client attempts to connect to is down, a <see cref="DisconnectedCallback"/> will be posted instead.
/// <see cref="UFSClient"/> will not attempt to reconnect to Steam, you must handle this callback and call <see cref="Connect"/> again, preferrably after a short delay.
/// In order to connect to the UFS server, the parent <see cref="SteamClient"/> must be connected to the CM server.
/// </summary>
/// <param name="ufsServer">
/// The <see cref="System.Net.IPEndPoint"/> of the UFS server to connect to.
/// If <c>null</c>, <see cref="UFSClient"/> will randomly select a UFS server from the <see cref="SteamClient"/>'s list of servers.
/// </param>
public void Connect(IPEndPoint ufsServer = null)
{
DebugLog.Assert(steamClient.IsConnected, "UFSClient", "CMClient is not connected!");
Disconnect();
if (ufsServer == null)
{
var serverList = steamClient.GetServersOfType(EServerType.UFS);
Random random = new Random();
ufsServer = serverList[random.Next(serverList.Count)];
}
connection.Connect(ufsServer, ( int )ConnectionTimeout.TotalMilliseconds);
}
/// <summary>
/// Performs an encryption using AES/CBC/PKCS7 with an input byte array and key, with a random IV prepended using AES/ECB/None
/// </summary>
public static byte[] SymmetricEncrypt(byte[] input, byte[] key)
{
DebugLog.Assert(key.Length == 32, "CryptoHelper", "SymmetricEncrypt used with non 32 byte key!");
using (var aes = new RijndaelManaged())
{
aes.BlockSize = 128;
aes.KeySize = 256;
// generate iv
byte[] iv = GenerateRandomBlock(16);
byte[] cryptedIv = new byte[16];
// encrypt iv using ECB and provided key
aes.Mode = CipherMode.ECB;
aes.Padding = PaddingMode.None;
using (var aesTransform = aes.CreateEncryptor(key, null))
{
cryptedIv = aesTransform.TransformFinalBlock(iv, 0, iv.Length);
}
// encrypt input plaintext with CBC using the generated (plaintext) IV and the provided key
aes.Mode = CipherMode.CBC;
aes.Padding = PaddingMode.PKCS7;
using (var aesTransform = aes.CreateEncryptor(key, iv))
using (var ms = new MemoryStream())
using (var cs = new CryptoStream(ms, aesTransform, CryptoStreamMode.Write))
{
cs.Write(input, 0, input.Length);
cs.FlushFinalBlock();
byte[] cipherText = ms.ToArray();
// final output is 16 byte ecb crypted IV + cbc crypted plaintext
byte[] output = new byte[cryptedIv.Length + cipherText.Length];
Array.Copy(cryptedIv, 0, output, 0, cryptedIv.Length);
Array.Copy(cipherText, 0, output, cryptedIv.Length, cipherText.Length);
return(output);
}
}
}
/// <summary>
/// Connects and initializes a session to the specified content server.
/// </summary>
/// <param name="csServer">The content server to connect to.</param>
/// <exception cref="System.ArgumentNullException">csServer was null.</exception>
/// <exception cref="HttpRequestException">An network error occurred when performing the request.</exception>
/// <exception cref="SteamKitWebRequestException">A network error occurred when performing the request.</exception>
public async Task ConnectAsync(Server csServer)
{
DebugLog.Assert(steamClient.IsConnected, "CDNClient", "CMClient is not connected!");
if (csServer == null)
{
throw new ArgumentNullException(nameof(csServer));
}
// Nothing needs to be done to initialize a session to a CDN server
if (csServer.Type == "CDN")
{
connectedServer = csServer;
return;
}
byte[] pubKey = KeyDictionary.GetPublicKey(steamClient.Universe);
sessionKey = CryptoHelper.GenerateRandomBlock(32);
byte[] cryptedSessKey = null;
using (var rsa = new RSACrypto(pubKey))
{
cryptedSessKey = rsa.Encrypt(sessionKey);
}
string data;
if (appTicket == null)
{
// no appticket, doing anonymous connection
data = string.Format("sessionkey={0}&anonymoususer=1&steamid={1}", WebHelpers.UrlEncode(cryptedSessKey), steamClient.SteamID.ConvertToUInt64());
}
else
{
byte[] encryptedAppTicket = CryptoHelper.SymmetricEncrypt(appTicket, sessionKey);
data = string.Format("sessionkey={0}&appticket={1}", WebHelpers.UrlEncode(cryptedSessKey), WebHelpers.UrlEncode(encryptedAppTicket));
}
var initKv = await DoCommandAsync(csServer, HttpMethod.Post, "initsession", data).ConfigureAwait(false);
sessionId = initKv["sessionid"].AsUnsignedLong();
reqCounter = initKv["req-counter"].AsLong();
connectedServer = csServer;
}
/// <summary>
/// Connects this client to a UFS server.
/// This begins the process of connecting and encrypting the data channel between the client and the UFS server.
/// Results are returned asynchronously in a <see cref="ConnectedCallback"/>.
/// If the UFS server that this client attempts to connect to is down, a <see cref="DisconnectedCallback"/> will be posted instead.
/// <see cref="UFSClient"/> will not attempt to reconnect to Steam, you must handle this callback and call <see cref="Connect"/> again, preferrably after a short delay.
/// In order to connect to the UFS server, the parent <see cref="SteamClient"/> must be connected to the CM server.
/// </summary>
/// <param name="ufsServer">
/// The <see cref="System.Net.IPEndPoint"/> of the UFS server to connect to.
/// If <c>null</c>, <see cref="UFSClient"/> will randomly select a UFS server from the <see cref="SteamClient"/>'s list of servers.
/// </param>
public void Connect(IPEndPoint ufsServer = null)
{
DebugLog.Assert(steamClient.IsConnected, "UFSClient", "CMClient is not connected!");
this.Disconnect();
pendingNetFilterEncryption = null;
if (ufsServer == null)
{
var serverList = steamClient.GetServersOfType(EServerType.UFS);
Random random = new Random();
ufsServer = serverList[random.Next(serverList.Count)];
}
connection.Connect(Task.FromResult(ufsServer), ( int )ConnectionTimeout.TotalMilliseconds);
}
void HandleEncryptResult( IPacketMsg packetMsg )
{
var result = new Msg<MsgChannelEncryptResult>( packetMsg );
log.LogDebug( nameof(EnvelopeEncryptedConnection), "Encryption result: {0}", result.Body.Result );
DebugLog.Assert( encryption != null, nameof( EnvelopeEncryptedConnection ), "Encryption is null" );
if ( result.Body.Result == EResult.OK && encryption != null )
{
state = EncryptionState.Encrypted;
Connected?.Invoke( this, EventArgs.Empty );
}
else
{
log.LogDebug( nameof(EnvelopeEncryptedConnection), "Encryption channel setup failed" );
Disconnect( userInitiated: false );
}
}
/// <summary>
/// Decrypts using AES/ECB/PKCS7
/// </summary>
public static byte[] SymmetricDecryptECB(byte[] input, byte[] key)
{
DebugLog.Assert(key.Length == 32, "CryptoHelper", "SymmetricDecryptECB used with non 32 byte key!");
using (var aes = new RijndaelManaged())
{
aes.BlockSize = 128;
aes.KeySize = 256;
aes.Mode = CipherMode.ECB;
aes.Padding = PaddingMode.PKCS7;
using (var aesTransform = aes.CreateDecryptor(key, null))
{
byte[] output = aesTransform.TransformFinalBlock(input, 0, input.Length);
return(output);
}
}
}
/// <summary>
/// Decrypts using AES/CBC/PKCS7 with an input byte array and key, using the IV (comprised of random bytes and the HMAC-SHA1 of the random bytes and plaintext) prepended using AES/ECB/None
/// </summary>
public static byte[] SymmetricDecryptHMACIV(byte[] input, byte[] key, byte[] hmacSecret)
{
if (input == null)
{
throw new ArgumentNullException(nameof(input));
}
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
if (hmacSecret == null)
{
throw new ArgumentNullException(nameof(hmacSecret));
}
DebugLog.Assert(key.Length >= 16, "CryptoHelper", "SymmetricDecryptHMACIV used with a key smaller than 16 bytes.");
var truncatedKeyForHmac = new byte[16];
Array.Copy(key, 0, truncatedKeyForHmac, 0, truncatedKeyForHmac.Length);
var plaintextData = SymmetricDecrypt(input, key, out var iv);
// validate HMAC
byte[] hmacBytes;
using (var hmac = new HMACSHA1(hmacSecret))
using (var ms = new MemoryStream())
{
ms.Write(iv, iv.Length - 3, 3);
ms.Write(plaintextData, 0, plaintextData.Length);
ms.Seek(0, SeekOrigin.Begin);
hmacBytes = hmac.ComputeHash(ms);
}
if (!hmacBytes.Take(iv.Length - 3).SequenceEqual(iv.Take(iv.Length - 3)))
{
throw new CryptographicException(string.Format(CultureInfo.InvariantCulture, "{0} was unable to decrypt packet: HMAC from server did not match computed HMAC.", nameof(NetFilterEncryption)));
}
return(plaintextData);
}
/// <summary>
/// Sends a packet immediately.
/// </summary>
/// <param name="packet">The packet.</param>
private void SendPacket(UdpPacket packet)
{
packet.Header.SourceConnID = sourceConnId;
packet.Header.DestConnID = remoteConnId;
packet.Header.SeqAck = inSeqAcked = inSeq;
log.LogDebug("UdpConnection", "Sent -> {0} Seq {1} Ack {2}; {3} bytes; Message: {4} bytes {5} packets",
packet.Header.PacketType, packet.Header.SeqThis, packet.Header.SeqAck,
packet.Header.PayloadSize, packet.Header.MsgSize, packet.Header.PacketsInMsg);
byte[] data = packet.GetData();
DebugLog.Assert(CurrentEndPoint != null, nameof(UdpConnection), "CurrentEndPoint should not be null when connected.");
try
{
sock.SendTo(data, CurrentEndPoint);
}
catch (SocketException e)
{
log.LogDebug("UdpConnection", "Critical socket failure: " + e.SocketErrorCode);
state = ( int )State.Disconnected;
return;
}
// If we've been idle but completely acked for more than two seconds, the next sent
// packet will trip the resend detection. This fixes that.
if (outSeqSent == outSeqAcked)
{
nextResend = DateTime.Now.AddSeconds(RESEND_DELAY);
}
// Sending should generally carry on from the packet most recently sent, even if it was a
// resend (who knows what else was lost).
if (packet.Header.SeqThis > 0)
{
outSeqSent = Math.Max(outSeqSent, packet.Header.SeqThis);
}
}