RustyStriker/online_security_project
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i think the server's register process is done

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This commit is contained in:
Rusty Striker 2024-12-20 11:23:49 +02:00
parent c4524fb62e
commit 90a3be5754
Signed by: RustyStriker
GPG key ID: 87E4D691632DFF15
6 changed files with 314 additions and 59 deletions
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79
client/Program.cs
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@ -19,7 +19,8 @@ public class Program
.FirstOrDefault() ?? "0000"; // get the value or deafult if it doesnt exist
// On boot, check if a key is available
RSA serverKey = LoadRSAFromFile("key_server.pem")!;
RSA? serverKey = LoadRSAFromFile("server_key.pem");
if (serverKey == null) { Console.WriteLine("Could not find server key, please run server before clients!"); return; }
RSA pubKey = LoadRSAFromFile($"pubkey_{user}.pem") ?? RSA.Create(2048);
RSA privKey = LoadRSAFromFile($"privkey_{user}.pem") ?? pubKey;
@ -33,15 +34,16 @@ public class Program
Aes sk = Aes.Create(); // creates an AES-256 key
if (needsRegister)
{
while(true) {
try {
await RegisterClient(user, pubKey, privKey, serverKey, sk, stream);
}
catch (Exception ex) {
Console.WriteLine("Failed registration process");
Console.WriteLine("Exception: " + ex.Message);
Console.WriteLine("Stack: " + ex.StackTrace);
}
try
{
await RegisterClient(user, pubKey, privKey, serverKey, sk, stream);
}
catch (Exception ex)
{
Console.WriteLine("Failed registration process");
Console.WriteLine("Exception: " + ex.Message);
Console.WriteLine("Stack: " + ex.StackTrace);
return;
}
}
else
@ -49,7 +51,6 @@ public class Program
}
var inputTask = Task.Run(async () => await HandleUserInput(client, stream));
var serverInput = Task.Run(async () => await HandleServerInput(client, stream));
@ -60,28 +61,36 @@ public class Program
async static Task RegisterClient(string user, RSA pub, RSA priv, RSA server, Aes sk, NetworkStream stream)
{
byte counter = 0;
// first send the `Register` message
// Generate aes key and send it forward
byte[] skEnc = server.Encrypt([.. sk.Key, .. sk.IV], RSAEncryptionPadding.OaepSHA256);
await stream.WriteAsync(skEnc);
// Generate the Register msg
byte[] pubBytes = pub.ExportRSAPublicKey();
byte[] data = new byte[16];
byte[] data = new byte[12];
Array.Copy(Utils.NumberToBytes(user), data, 8);
Array.Copy(BitConverter.GetBytes(pubBytes.Length), 0, data, 8, 4);
Array.Copy(BitConverter.GetBytes(sk.Key.Length), 0, data, 12, 4);
byte[] msg = Request.CreateRequest(RequestType.Register, ref counter, data);
byte[] finalPayload = [.. msg, .. pubBytes, .. sk.Key];
// signing a hash here is pretty useless tbh
// if oscar is changing this message somehow it will just fail the registration process and will restart eventually
// so kinda pointless, esp when its signed with the server's key
byte[] enc = server.Encrypt(finalPayload, RSAEncryptionPadding.OaepSHA256);
await stream.WriteAsync(enc);
// get the 6 digit code
// Encrypt msg and send it
byte[] enc = sk.EncryptCfb(msg, sk.IV, PaddingMode.PKCS7);
byte[] payload = [.. enc, .. pubBytes];
await stream.WriteAsync(payload);
// get the 6 digit code (from "secure channel", actually an OK message is expected here but the 6 digit code kinda replaces it)
byte[] digits = new byte[6];
await stream.ReadExactlyAsync(digits, 0, 6);
int len = 0;
while (len != 6)
{
len = await stream.ReadAsync(digits);
}
// print the 6 digit code
Console.WriteLine($"[{DateTime.Now}] 6 digit code: {string.Join(' ',digits.Select(d => d.ToString()))}");
Console.WriteLine($"[{DateTime.Now}] 6 digit code: {string.Join(' ', digits.Select(d => d.ToString()))}");
// get the 6 digit code from the user
while(true) {
while (true)
{
string? code = Console.ReadLine()?.Trim();
if(code == null || code.Take(6).Any(c => !char.IsDigit(c))) {
if (code == null || code.Take(6).Any(c => !char.IsDigit(c)))
{
Console.WriteLine("Invalid code!");
continue;
}
@ -89,15 +98,21 @@ public class Program
.Take(6) // take the first 6 characters
.Select(d => byte.Parse(d.ToString())) // parse into bytes
.ToArray();
msg = Request.CreateRequest(RequestType.ConfirmRegister, ref counter, codeBytes);
byte[] signed = priv.SignData(msg, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
enc = sk.EncryptCfb(msg, Array.Empty<byte>(), PaddingMode.None); // no reason to encrpy the signature
finalPayload = [.. enc, .. signed]; // should be 128 (enc) + 256 (signed)
await stream.WriteAsync(finalPayload);
// Debug print the inserted value to see it works :)
Console.WriteLine(string.Join(' ', codeBytes.Select(b => b.ToString())));
// Sign the 6 digit code & Generate ConfirmRegister message
byte[] signed = priv.SignData(codeBytes, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
msg = Request.CreateRequest(RequestType.ConfirmRegister, ref counter, [.. codeBytes, .. BitConverter.GetBytes(signed.Length)]);
enc = sk.EncryptCfb(msg, sk.IV, PaddingMode.PKCS7); // no reason to encrpy the signature
payload = [.. enc, .. signed]; // should be 128 (enc) + 256 (signed)
await stream.WriteAsync(payload);
// wait for OK/NACK response (anything other than OK is a NACK)
int incoming = await stream.ReadAsync(enc);
msg = sk.DecryptCfb(enc[..incoming], Array.Empty<byte>(), PaddingMode.Zeros);
msg = sk.DecryptCfb(enc[..incoming], sk.IV, PaddingMode.PKCS7);
string r = Encoding.UTF8.GetString(msg);
if(r == "OK") {
if (r == "OK")
{
Console.WriteLine("Registration process complete");
break;
}