public static Meta GetSecure(Socket client, Stream toWriteTo, byte[] encryptionKey)
{
Meta meta = GetMeta(client);
AesGcm gcm = new AesGcm(encryptionKey);
byte[] buffer = new byte[FileBufferSize + TagBufferSize];
int clientGetBuffer = client.SendBufferSize;
client.ReceiveBufferSize = FileBufferSize + TagBufferSize;
BigInteger count = 0;
for (BigInteger i = 0; meta.Size != count; i++)
{
int bytes = client.Receive(buffer, buffer.Length, SocketFlags.None);
count += bytes - TagBufferSize;
byte[] cypher = subArray(buffer, 0, bytes - TagBufferSize);
byte[] tag = subArray(buffer, bytes - TagBufferSize, bytes);
byte[] nonce = Base255.ToByteArr(i, NonceBufferSize);
byte[] plainText = new byte[cypher.Length];
gcm.Decrypt(nonce, cypher, tag, plainText);
toWriteTo.Write(plainText, 0, plainText.Length);
}
client.ReceiveBufferSize = clientGetBuffer;
return(meta);
}
/// <summary>
/// Gets meta file structure from client.
/// Abstain from using this method, unless you know how it works.
/// <para/>
/// See <see cref="Transfer.Send(Socket, Meta, System.IO.Stream)"/>,
/// or see <see cref="Transfer.SendFile(Socket, string)"/>
/// </summary>
/// <exception cref="System.Exception">
/// Thrown when the promised bytes and received bytes don't match.
/// </exception>
/// <exception cref="System.Net.Sockets.SocketException">
/// Thrown when a receive operation has failed, the client has disconnected.
/// </exception>
public static Meta GetMeta(Socket client)
{
// Get
byte[] metaBuffer = new byte[MetaBufferSize];
int clientBufferSize = client.ReceiveBufferSize;
client.ReceiveBufferSize = metaBuffer.Length;
int bytes = client.Receive(metaBuffer);
// Probably disconnected.
if (bytes == 0)
{
throw new SocketException((int)SocketError.NotConnected);
}
// Lengths don't match.
if (bytes != metaBuffer.Length)
{
throw new Exception("Not enough metadata");
}
logger.Log($"Got meta buffer - [{string.Join(",", metaBuffer)}]", LoggerState.Debug);
// Split
byte[] nameBuffer = subArray(metaBuffer, 0, NameBufferSize);
byte[] sizeBuffer = subArray(metaBuffer, NameBufferSize, metaBuffer.Length);
// Clean nameBuffer, first 'non-blank' element.
int nonZeroIndex = 0;
for (int i = 0; i < nameBuffer.Length; i++)
{
if (nameBuffer[i] < 32) // If its not a letter (ASCII)
{
nonZeroIndex = i;
break;
}
}
Array.Resize(ref nameBuffer, nonZeroIndex);
// Parse
logger.Log($"Got size buffer [{string.Join(",", sizeBuffer)}]", LoggerState.Debug);
BigInteger number = Base255.ToBigInt(sizeBuffer);
logger.Log("Parsed as " + number, LoggerState.Debug);
string name = System.Text.Encoding.UTF8.GetString(nameBuffer);
client.ReceiveBufferSize = clientBufferSize;
return(new Meta(name, number));
}
public static void SendSecure(Socket client, Meta meta, Stream data, byte[] encryptionKey)
{
SendMeta(client, meta);
AesGcm gcm = new AesGcm(encryptionKey);
byte[] buffer = new byte[FileBufferSize];
int clientSendBuffer = client.SendBufferSize;
client.SendBufferSize = FileBufferSize + TagBufferSize;
BigInteger count = 0;
for (BigInteger i = 0; count != meta.Size; i++)
{
int bytes = data.Read(buffer, 0, buffer.Length);
count += bytes;
logger.Log($"[{i}] Count: {count}", LoggerState.Debug);
if (bytes != buffer.Length)
{
Array.Resize(ref buffer, bytes);
}
byte[] tag = new byte[16];
byte[] cyphertext = new byte[buffer.Length];
byte[] nonce = Base255.ToByteArr(i, NonceBufferSize);
gcm.Encrypt(nonce, buffer, cyphertext, tag);
logger.Log($"Cypher: {string.Join(',', cyphertext)}", LoggerState.Debug);
logger.Log($"Tag: {string.Join(',', tag)}", LoggerState.Debug);
logger.Log($"Nonce: {string.Join(',', nonce)}", LoggerState.Debug);
byte[] unifiedEnc = new byte[cyphertext.Length + tag.Length];
cyphertext.CopyTo(unifiedEnc, 0);
tag.CopyTo(unifiedEnc, cyphertext.Length);
client.Send(unifiedEnc, unifiedEnc.Length, SocketFlags.None);
}
client.SendBufferSize = clientSendBuffer;
}
/// <summary>
/// Sends meta file structure to host via client. Check netconf.json for meta structure.
/// </summary>
/// <exception cref="System.Net.Sockets.SocketException">
/// Thrown when a send operation has failed, the host has disconnected.
/// </exception>
public static void SendMeta(Socket client, Meta meta)
{
byte[] metaBuffer = new byte[MetaBufferSize];
int clientBufferSize = client.ReceiveBufferSize;
client.SendBufferSize = metaBuffer.Length;
// Cap filename to NameBufferSize
string filename = meta.Name;
if (filename.Length > NameBufferSize)
{
filename = filename.Substring(0, NameBufferSize);
}
// Copy to the meta buffer.
Encoding.UTF8.GetBytes(filename).CopyTo(metaBuffer, 0);
// Copy the converted size to meta buffer.
byte[] byteArr = Base255.ToByteArr(meta.Size);
logger.Log($"Compressing {meta.Size} into [{string.Join(",", byteArr)}]", LoggerState.Debug);
for (int i = 0; i < byteArr.Length; i++)
{
metaBuffer[(NameBufferSize) + i] = byteArr[i];
}
logger.Log($"Sending meta buffer - [{string.Join(",", metaBuffer)}]", LoggerState.Debug);
// Send to client
int bytes = client.Send(metaBuffer);
// If no bytes received, probably disconnected.
if (bytes == 0)
{
throw new SocketException((int)SocketError.NotConnected);
}
client.SendBufferSize = clientBufferSize;
}
