Hi, I was trying to create a text file and write to it. However, every time I run the test, I was able to create the file or write to the file but got an error when I wanted to create and write to it. Below is my example.

void main() { test('', () async { final socket = await SSHSocket.connect('localhost', 22);

final client = SSHClient(
  socket,
  username: 'yh',
  onPasswordRequest: () => 'secret',
);

final sftp = await client.sftp();
await sftp.open(
  'asdf.txt',
  mode: SftpFileOpenMode.create,
);

final file1 = await sftp.open('asdf.txt', mode: SftpFileOpenMode.write);
final lists = 'asdfasdf'.codeUnits;
await file1.writeBytes(Uint8List.fromList(lists));

client.close();
await client.done;

}); }

I know this is kind of an edge case, however I am trying to log into the sftp server of a piece of equipment I work with, and it requires some sort of keyboard interaction with the cl as part of the password. I have been poking around several different packages, and have not been able to figure out how this works. I was able to sign in using the node library 'ssh2-sftp-client' with the parameter of 'tryKeyboard' set to true. I would really prefer to build this as a flutter app, instead of js. Is there a way in the 'onPasswordRequest' function that I can add this keyboard interaction?

The following code fails on stat or open. The sftp site is a site with public access. I am able to test the site access with FileZilla without any issues. The same behavior on both Linux and Windows.

import 'package:dartssh2/dartssh2.dart';

void main(List<String> args) async {
  final socket = await SSHSocket.connect('sftp.floridados.gov', 22);

  final client = SSHClient(
    socket,
    username: 'Public',
    onPasswordRequest: () => 'PubAccess1845!',
    onAuthenticated: () => print('*** Signed in'),
    printTrace: (msg) => print('TRACE: $msg'),
    printDebug: (msg) => print('DEBUG: $msg'),
  );

  final sftp = await client.sftp();
  print('*** Before calling stat');
  final stat = await sftp.stat('/');

  print(stat.size);
  print(stat.mode);

  client.close();
  await client.done;
}

StackTrace:

Unhandled exception:
FormatException: Unexpected extension byte (at offset 0)
#0      _Utf8Decoder.convertSingle (dart:convert-patch/convert_patch.dart:1755:7)
#1      Utf8Decoder.convert (dart:convert/utf.dart:351:42)
#2      Utf8Codec.decode (dart:convert/utf.dart:63:20)
#3      SSHMessageReader.readUtf8 (package:dartssh2/src/ssh_message.dart:75:17)
#4      new SftpVersionPacket.decode (package:dartssh2/src/sftp/sftp_packet.dart:105:28)
#5      SftpClient._handleVersionPacket (package:dartssh2/src/sftp/sftp_client.dart:410:38)
#6      SftpClient._handlePacket (package:dartssh2/src/sftp/sftp_client.dart:392:16)
#7      SftpClient._handlePackets (package:dartssh2/src/sftp/sftp_client.dart:384:7)
#8      SftpClient._handleData (package:dartssh2/src/sftp/sftp_client.dart:374:5)
#9      _RootZone.runUnaryGuarded (dart:async/zone.dart:1618:10)
#10     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
#11     _DelayedData.perform (dart:async/stream_impl.dart:591:14)
#12     _StreamImplEvents.handleNext (dart:async/stream_impl.dart:706:11)
#13     _PendingEvents.schedule.<anonymous closure> (dart:async/stream_impl.dart:663:7)
#14     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#15     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
#16     _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:122:13)
#17     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:193:5)

final sftp = await client.sftp();
final items = await sftp.listdir('/');
for (final item in items) {
  if ((file.attr.isSymbolicLink)){
     print(item.longname);
  }
}

Perhaps I missed it when going though the code but I couldn't find a way to remove characters from a file using the SFTP client, other than by truncating the entire file.

Is there a way to do that with this library?

Example:

import 'dart:io';
import 'package:dartssh2/dartssh2.dart';

void main() async {
  var client = SSHClient(
    await SSHSocket.connect("192.168.0.1", 22),
    username: "root",
    onPasswordRequest: () => "mypass",
  );

  final session = await client.execute('sleep 10');
  stdout.addStream(session.stdout);
  stderr.addStream(session.stderr); 
  
  session.done.then((_) {
    print("session done");
    client.close();
  }).catchError((err) {
    print("session errored");
    client.close();
  });

  await Future.delayed(Duration(seconds: 2));
  session.kill(SSHSignal.INT);
}

Alternatively:

import 'dart:io';
import 'package:dartssh2/dartssh2.dart';

void main() async {
  var client = SSHClient(
    await SSHSocket.connect("192.168.0.1", 22),
    username: "root",
    onPasswordRequest: () => "mypass",
  );

  final session = await client.execute('sleep 10');
  stdout.addStream(session.stdout);
  stderr.addStream(session.stderr); 
  
  await Future.delayed(Duration(seconds: 2));
  session.kill(SSHSignal.INT);

  await session.done;
  client.close();
}

Will both result in this exception being thown:

Unhandled exception:
Null check operator used on a null value
#0      SSHSession._handleRequest (package:dartssh2/src/ssh_session.dart:119:41)
#1      SSHChannelController._handleRequestMessage (package:dartssh2/src/ssh_channel.dart:234:36)
#2      SSHChannelController.handleMessage (package:dartssh2/src/ssh_channel.dart:185:7)
#3      SSHClient._handleChannelRequest (package:dartssh2/src/ssh_client.dart:705:42)
#4      SSHClient._dispatchMessage (package:dartssh2/src/ssh_client.dart:489:16)
#5      SSHClient._onPacket (package:dartssh2/src/ssh_client.dart:432:7)
#6      SSHTransport._handleMessage (package:dartssh2/src/ssh_transport.dart:639:19)
#7      SSHTransport._processPackets (package:dartssh2/src/ssh_transport.dart:312:7)
#8      SSHTransport._processData (package:dartssh2/src/ssh_transport.dart:257:7)
#9      SSHTransport._onSocketData (package:dartssh2/src/ssh_transport.dart:235:7)
#10     _RootZone.runUnaryGuarded (dart:async/zone.dart:1620:10)
#11     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
#12     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#13     _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:733:19)
#14     _StreamController._add (dart:async/stream_controller.dart:607:7)
#15     _StreamController.add (dart:async/stream_controller.dart:554:5)
#16     _Socket._onData (dart:io-patch/socket_patch.dart:2166:41)
#17     _RootZone.runUnaryGuarded (dart:async/zone.dart:1620:10)
#18     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
#19     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#20     _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:733:19)
#21     _StreamController._add (dart:async/stream_controller.dart:607:7)
#22     _StreamController.add (dart:async/stream_controller.dart:554:5)
#23     new _RawSocket.<anonymous closure> (dart:io-patch/socket_patch.dart:1702:33)
#24     _NativeSocket.issueReadEvent.issue (dart:io-patch/socket_patch.dart:1213:14)
#25     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#26     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)
#27     _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:120:13)
#28     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:185:5)

The problem also happens with shell.kill(), and won't happen if you dont use the .done promise

Hi!

I want to copy a file (.tgz) from my host to the server (scp isn't available).

I tried

final session = await client.execute("tar -zxf -");
session.write(filebytes);

but without success. I think the problem is that tar don't know when he should stop listening on stdin.

I got the same result with cat > file.tgz.

Is there a way to copy a file from host to remote without scp?

Thanks for your help!

It was observed that there are ssh-2 servers that are not compliant with RFC4253 and terminate the version string only with (not preceded by ).

This PR aims to support this kind of non-compliant server.

The observation was made on a Synology NAS DS120j (kernel date March 2021):

$ uname -a
Linux NAS11 4.4.59+ #25556 SMP Thu Mar 4 18:01:32 CST 2021 aarch64 GNU/Linux synology_armada37xx_ds120j

Inside my main.dart I want to make a remote forwarding call like this:

ssh -R 80:127.0.0.1:3000 user@<remote_server_ip>

Is that currently possible and if so how would I go about doing it?

SSHDiffieHellman is comment out, could remove this comment, and show EllipticCurveDiffieHellman, DiffieHellman & ScalarMult? thanks :) https://github.com/TerminalStudio/dartssh2/blob/3316b252ace4948f64812b7e5eca11f466d3f62d/lib/dartssh2.dart#L19

I tested the local port forwarding feature, but cannot get it running.

SSH Command I want to run: ssh 172.17.0.2 -l root -L 1234:localhost:80 With the dart client: dart run dartssh.dart -l root 172.17.0.2 --debug --password test --tunnel localhost:80

Is my command right at this point?

It says tunnel is up, but curl 127.0.0.1:1234 responds connection refused.

Hello. I wonder if there are any plans to implement Host Key Verification function. (Server host key can be returned, whether to connect through server host key acceptance)

As in the following ssh2.js (SSH client implemented in JavaScript) hostVerifier example, I would like to be given a server hash to compare against, and handle the process of accepting or rejecting connections via a callback.

https://github.com/mscdex/ssh2#:~:text=Default%3A%20(none)-,hostVerifier,-%2D%20function%20%2D%20Function

If this is not currently possible, it would be nice if implemented in the future.

Regards,

When attempting to SFTP upload an empty file (with 0 bytes in size) the upload halts (neither raises an error, no exits the program).

The client machine where the program is executes is Windows the remote one is Amazon Linux 2.

One might wonder what is the use case for such files. Sometime programs create programx.lock files which are used as a persisted on file system boolean switch.

this is log:

flutter: SSHTransport._sendKexInit flutter: SSHTransport._processVersionExchange flutter: SSHTransport._remoteVersion = "SSH-2.0-OpenSSH_6.4" 2 flutter: SSHTransport._processPackets flutter: SSHTransport._consumeClearTextPacket flutter: SSHTransport._handleMessageKexInit flutter: SSHTransport._kexType: SSHKexType(ecdh-sha2-nistp521) flutter: SSHTransport._hostkeyType: SSHHostkeyType(ssh-rsa) flutter: SSHTransport._clientCipherType: SSHCipherType(aes128-ctr) flutter: SSHTransport._serverCipherType: SSHCipherType(aes128-ctr) flutter: SSHTransport._clientMacType: SSHMacType(hmac-sha1) flutter: SSHTransport._serverMacType: SSHMacType(hmac-sha1) flutter: SSHTransport._sendKexDHInit flutter: SSHTransport._processPackets flutter: SSHTransport._consumeClearTextPacket flutter: SSHTransport._handleMessageKexReply flutter: SSHTransport._consumeClearTextPacket flutter: SSHTransport._handleMessageNewKeys flutter: SSHTransport._sendNewKeys flutter: SSHClient._onTransportReady flutter: SSHClient._requestAuthentication flutter: SSHTransport._processPackets flutter: SSHTransport._consumeEncryptedPacket flutter: SSHClient._startAuthentication flutter: SSHClient._tryNextAuthenticationMethod flutter: _currentAuthMethod = SSHAuthMethod.publicKey flutter: SSHClient._authWithPublicKey flutter: SSHTransport._processPackets flutter: SSHTransport._consumeEncryptedPacket flutter: SSHClient._handleUserauthFailure flutter: SSHClient._tryNextAuthenticationMethod flutter: _currentAuthMethod = SSHAuthMethod.none flutter: SSHClient._authWithNone flutter: SSHTransport._processPackets flutter: SSHTransport._consumeEncryptedPacket flutter: SSHClient._handleUserauthFailure flutter: SSHClient._tryNextAuthenticationMethod flutter: SSHTransport.closeWithError SSHAuthFailError(All authentication methods failed)

I try to use FileZilla to connect, it's fine. So I don't know where I'm going wrong

Hello. Thanks for creating & developing the dartssh2 project.

I am developing a terminal app with shell interaction using dartssh2.

Are the KeepAliveInterval and KeepAliveCountMax values configurable via dartssh2 options on the client?

I looked for a similar issue below but couldn't find the answer I was looking for. https://github.com/TerminalStudio/dartssh2/issues/27

If not, hopefully a feature will be added in the future.

Regards,

(Please ignore the problem I had below. It was a hardware issue with my development rig.)

E/flutter (21226): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: SSHStateError(Transport is closed)
E/flutter (21226): #0      SSHTransport.sendPacket (package:dartssh2/src/ssh_transport.dart:183:7)
E/flutter (21226): #1      SSHClient._sendMessage (package:dartssh2/src/ssh_client.dart:460:16)
E/flutter (21226): #2      SSHChannelController._sendEOFIfNeeded (package:dartssh2/src/ssh_channel.dart:269:16)
E/flutter (21226): #3      SSHChannelController.close (package:dartssh2/src/ssh_channel.dart:200:5)
E/flutter (21226): #4      SSHClient._closeChannels (package:dartssh2/src/ssh_client.dart:428:15)
E/flutter (21226): #5      SSHClient._onTransportClosed (package:dartssh2/src/ssh_client.dart:447:5)
E/flutter (21226): #6      new SSHClient.<anonymous closure> (package:dartssh2/src/ssh_client.dart:161:23)
E/flutter (21226): #7      _RootZone.runUnary (dart:async/zone.dart:1653:54)
E/flutter (21226): #8      _FutureListener.handleError (dart:async/future_impl.dart:165:22)
E/flutter (21226): #9      Future._propagateToListeners.handleError (dart:async/future_impl.dart:778:47)
E/flutter (21226): #10     Future._propagateToListeners (dart:async/future_impl.dart:799:13)
E/flutter (21226): #11     Future._completeError (dart:async/future_impl.dart:574:5)
E/flutter (21226): #12     Future._asyncCompleteError.<anonymous closure> (dart:async/future_impl.dart:665:7)
E/flutter (21226): #13     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
E/flutter (21226): #14     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)

Connection code

connect() async {
    final socket = await SSHSocket.connect('host', 'port');

    _client = SSHClient(
      socket,
      username: 'username',
      onPasswordRequest: () {
        return 'password';
      },
    );

    _shell = await _client.shell();
}

pubspec.yarn

dependencies:
  flutter:
    sdk: flutter

  dartssh2: 2.7.3

Hi !

Is there a way to write from the code to the shell and not the IDE terminal

I'm implementing the code form the shell example and it works fine:

final shell = await client.shell();
stdout.addStream(shell.stdout);
stderr.addStream(shell.stderr);
stdin.cast<Uint8List>().listen(shell.write);

But I would like to be able to write multiple entry lines from the code to the open shell