//constracts and appends mac
public void CalcHash(MAC mac, int sequence)
{
byte[] buf = new byte[4 + 4 + _packetLength];
SSHUtil.WriteIntToByteArray(buf, 0, sequence);
WriteTo(buf, 4, false);
_mac = mac.Calc(buf);
}
public static SSH2Packet FromDecryptedHead(byte[] head, byte[] buffer, int offset, Cipher cipher, int sequence, MAC mac)
{
SSH2Packet p = new SSH2Packet();
p._packetLength = SSHUtil.ReadInt32(head, 0);
if (p._packetLength <= 0 || p._packetLength >= MAX_PACKET_LENGTH)
{
throw new SSHException(String.Format("packet size {0} is invalid", p._packetLength));
}
SSH2DataWriter buf = new SSH2DataWriter();
buf.Write(sequence);
buf.Write(head);
if (p._packetLength > (cipher.BlockSize - 4))
{
byte[] tmp = new byte[p._packetLength - (cipher.BlockSize - 4)];
cipher.Decrypt(buffer, offset, tmp.Length, tmp, 0);
offset += tmp.Length;
buf.Write(tmp);
}
byte[] result = buf.ToByteArray();
int padding_len = (int)result[8];
if (padding_len < 4)
{
throw new SSHException("padding length is invalid");
}
byte[] payload = new byte[result.Length - 9 - padding_len];
Array.Copy(result, 9, payload, 0, payload.Length);
p._payload = payload;
if (mac != null)
{
p._mac = mac.Calc(result);
if (SSHUtil.memcmp(p._mac, 0, buffer, offset, mac.Size) != 0)
{
throw new SSHException("MAC Error");
}
}
return(p);
}
//constracts and appends mac
public void CalcHash(MAC mac, int sequence)
{
byte[] buf = new byte[4+4+_packetLength];
SSHUtil.WriteIntToByteArray(buf, 0, sequence);
WriteTo(buf, 4, false);
_mac = mac.Calc(buf);
}
public static SSH2Packet FromDecryptedHead(byte[] head, byte[] buffer, int offset, Cipher cipher, int sequence, MAC mac)
{
SSH2Packet p = new SSH2Packet();
p._packetLength = SSHUtil.ReadInt32(head, 0);
if(p._packetLength<=0 || p._packetLength>=MAX_PACKET_LENGTH) throw new Exception(String.Format("packet size {0} is invalid", p._packetLength));
SSH2DataWriter buf = new SSH2DataWriter();
buf.Write(sequence);
buf.Write(head);
if(p._packetLength > (cipher.BlockSize - 4)) {
byte[] tmp = new byte[p._packetLength-(cipher.BlockSize - 4)];
cipher.Decrypt(buffer, offset, tmp.Length, tmp, 0);
offset += tmp.Length;
buf.Write(tmp);
}
byte[] result = buf.ToByteArray();
int padding_len = (int)result[8];
if(padding_len<4) throw new Exception("padding length is invalid");
byte[] payload = new byte[result.Length-9-padding_len];
Array.Copy(result, 9, payload, 0, payload.Length);
p._payload = payload;
if(mac!=null) {
p._mac = mac.Calc(result);
if(SSHUtil.memcmp(p._mac, 0, buffer, offset, mac.Size)!=0)
throw new Exception("MAC Error");
}
return p;
}
