2016.1.0-beta4

Fixes

General

• Servers that do not implement RFC 4252 correctly may lead to stack overflow (issue #306).

  Section 5.1 of the aforementioned RFC states the following on SSH_MSG_USERAUTH_FAILURE response:

  The value of 'partial success' MUST be TRUE if the authentication request to which this is a response was successful. It MUST be FALSE if the request was not successfully processed.

  Some SSH servers set 'partial success' to TRUE even if the authentication request was not processed successfully, and do not update the name-list to remove the method name that failed.

  SSH.NET has now been updated only attempt authentication 5 times for a method that was considered partially successful.

  If this limit is reached for a given method name, and no other authentication method is available, a SshAuthenticationException with message "Reached authentication attempt limit for method (<method name>)" will be thrown.

• Key exchange is slow when size of group is more than 1024 bit (issue #304 and #130).

  As part of the key exchange, SSH.NET sends a SSH_MSG_KEY_DH_GEX_REQUEST with a 1024 bit minimum and preferred group size, and 8192 bit maximum group size.

  Before this fix, we would generate a private exponent that matches the size of the safe prime generated by the server. In some cases this meant using a 8192 bit private component to generate the client exchange value, which is a CPU intensive operation.

  As from this fix, we generate a private exponent that is twice the hash size with a minimum of 1024 bit.

2016.1.0-beta3

Changes

ScpClient

A RemotePathTransformation property has been added to ScpClient that can be used to change if and how a remote path is transformed before it is passed to the scp command on the remote server.

SSH.NET comes with the following path transformations that are exposed through the RemotePathTransformation class (in Renci.SshNet):

• DoubleQuote
  Encloses a path in double quotes, and escapes any embedded double quote with a backslash.
  This is the default, as it works fine with most SCP servers.

• ShellQuote
  Quotes a path in a way to be suitable to be used with a shell-based SCP server.
  This is the preferred mechanism for shell-based SCP servers, which typically means all Unix-like systems.

• None
  Performs no transformation to the path.
  This is the recommended transformation when the remote host does not require any quoting to preserve the literal value of metacharacters, or when remote paths are guaranteed not to contain such characters.

When none of the built-in transformations match the specific requirements of a remote host, a custom transformation can be supplied.

More information on this change is available here.

Fixes issues #256 and #108.

Example:

Download a file using SCP, and apply shell quoting to the remote path:

using Renci.SshNet;

public class Program
{
  static void Main()
  {
      using (var client = new ScpClient("HOST", 22, "USER", "PWD"))
      {
          client.RemotePathTransformation = RemotePathTransformation.ShellQuote;
          client.Connect();

          using (var ms = new MemoryStream())
          {
              client.Download("/home/sshnet/file 123", ms);
          }
      }
  }
}

Since we've configured ScpClient to use the ShellQuote transformation, the /home/sshnet/file 123 path
will automatically be enclosed in single quotes.

The actual path that is passed to the scp command on the remote host is therefore '/home/sshnet/file 123'.

Breaking changes

ScpClient

The Upload(FileInfo fileInfo, String path) method in ScpClient now expects path to be the remote path of the file to which you want to upload, and throws a ScpException if a directory exists on the remote host for that path (issue #286).

Up until now, uploading a file with a given (remote) path could lead a different result depending on whether a directory for that path exits on the remote host.

Example:

  using (var client = new ScpClient("host", "user", "pwd"))
  {
      client.Connect();

      client.Upload(new FileInfo(@"c:\temp\newlog.txt", "/home/sshnet/log");
  }

As of version 2016.1.0-beta3 a ScpException will be thrown when /home/sshnet/log exists as a directory on the remote host.

In previous versions of SSH.NET this code would actually upload the content of the c:\temp\newlog.txt file to /home/sshnet/log/newlog.txt.

When /home/sshnet/log exists on the remote host as a file or does not exist at all, the content of the c:\temp\newlog.txt file will be uploaded to /home/sshnet/log. This has not changed.

Fixes

ScpClient

• Upload(Stream source, String path) does not support uploading a file to the home directory using a relative path (issue #280).

  The following code will now just work:

  using (var client = new ScpClient("host", "user", "pwd"))
  {
      client.Connect();
  
      using (var fs = File.OpenRead(@"c:\file.log"))
      {
          client.Upload(fs, "file.log");
      }
  }

• Upload(Stream source, String path) does not throw an exception when parent directory does not exist (issue #289).

• ScpClient does not support non-ASCII characters in downloaded file names or error message (issue #281).

SftpClient

• DowloadFile(String path, Stream output, Action<UInt64>) does not perform well on Sun SSH (issue #292).

SshClient

• ShellStream.Write(byte[] buffer, Int32 offset, Int32 count) skips a single byte when buffer is full (PR #211).
• CreateShellStream overloads always use a 1024 byte buffer (issue #303)

2016.1.0-beta2

Changes

General

• Increase initial window size for SSH channels from 2 MB to 2147483647 (2^31 - 1) bytes. This results in less protocol overhead when receiving data from a SSH server.

SftpClient

• When the read buffer is empty, SftpFileStream.Read(byte[], int, int) only writes those bytes to the buffer that go beyond the number of bytes requested by the caller.
• Reduced memory allocations in SftpFileStream by lazily allocating read and write buffer.
• Improved compatibility of SftpFileStream.SetLength(long value) with System.IO.FileStream (PR #272):
  • Flush buffers before changing the length of stream.
  • Move the current position to the last byte of the stream if the current position is greater than the new length.
• Eliminated extra read from server in SftpFileStream to determine EOF.
• Greatly improved performance of SftpClient.(Begin)DownloadFile(...) by asynchronously reading ahead chunks (issue #145 and #100).

Breaking changes

SftpClient

• The IsAsync property was removed from SftpFileStream. Previously this property always returned false.

• The read and write position in SftpFileStream are no longer tracked separately. Reading from or seeking in the SftpFileStream will now also affect the position at which a subsequent write is performed, and vice versa (issue #253).

  For example, the following code snippet will now write "123456" to the console:

    var buffer = Encoding.UTF8.GetBytes("123456");

    using (var client = new SftpClient("host", "user", "pwd"))
    {
        client.Connect();

        using (var ws = client.OpenWrite(path))
        {
            ws.Write(buffer, 0, 3);
        }

        using (var ws = client.OpenWrite(path))
        {
            ws.Seek(3, SeekOrigin.Begin);
            ws.Write(buffer, 3, 3);
        }

        Console.WriteLine(client.ReadAllText(path, Encoding.UTF8));
    }

• To improve compatibility of SftpFileStream with System.IO.FileStream, Append mode is now only allowed when combined with write-only access (issue #267). This only affects SftpClient.Open(string path, FileMode mode, FileAccess access).

  The following code snippet will now throw an ArgumentException:

    using (var client = new SftpClient("host", "user", "pwd"))
    {
        client.Connect();
  
        using (var fs = client.Open("/home/user/file.log", FileMode.Append, FileShare.Read))
        {
        }
    }

  Result:
  System.ArgumentException: Append mode can be requested only when combined with write-only access.

• To improve compatibility of SftpClient with System.IO.File, the following methods now use UTF-8 encoding without a Byte-Order Mark (BOM):

  • void AppendAllLines(string path, IEnumerable<string> contents)
  • void AppendAllText(string path, string contents)
  • StreamWriter AppendText(string path)
  • StreamWriter CreateText(string path)
  • void WriteAllLines(string path, IEnumerable<string> contents)
  • void WriteAllLines(string path, string[] contents)
  • void WriteAllText(string path, string contents)

Fixes

General

• ConnectSocks5() throws a ProxyException with a wrong message (issue #167).
• Comments in ProxyException.cs are not relevant (issue #163).
• SSH exception after client connect using .NET 3.5 version (issue #113).

SftpClient

• SftpFileStream allows invalid combinations of FileMode and FileAccess (issue #191).
• SftpFileStream.ReadByte() throws ArgumentException when no data is available in read buffer (issue #173).
• SftpFileStream also sends SSH_FXP_FSTAT upon initialization when mode is not Append (issue #154).
• In Append mode, SftpFileStream throws a SftpPathNotFoundException when the specified file does not exist (issue #266).

2016.1.0-beta1

New Features

SshClient

• A ForwardedPortDynamic now supports domain name addresses for SOCKS5 requests (issue #98).

Changes

Distribution

The NuGet Package Manager in Visual Studio 2012 does not support packages in which a given dependency is defined for more than one TFM. Since a fix for this issue is not expected any time soon, we're reviving support for a binary distribution.

This plain .zip file contains the SSH.NET assembly, and where applicable any dependencies, for all supported target frameworks.

For Visual Studio 2015 and higher, the SSH.NET NuGet package remains our primary distribution mechanism.

General

• Data of an SSH_MSG_IGNORE server request is now ignored when the specified length is greater than the actual available bytes (issue #41).

SshClient

• ForwardedPort.Stop() no longer throws ObjectDisposedException when the port is disposed.

Performance

• Reduce overhead when invoking both Disconnect() and Dispose().
• Improve performance of SSH message processing by eliminating use of dynamic dispatching.

Fixes

General

• Handle leak when connection to SSH server fails (issue #55).
• Race condition when both server and client close channel (issue #84).
• Suppressing a not-connected exception on socket shutdown (issue #86).
• Race condition when both server and client disconnect (issue #80).
• Do not consume request-specific data for SSH_MSG_GLOBAL_REQUEST (issue #58).
• SocketAsyncEventArgs leak establishing socket connection (issue #133 and #87).

SftpClient

• Uploads with a buffer size that is less than or greather than 32 Kb would corrupt (issue #70).

SshClient

• Dispose() throws exception when SSH session gets disconnected unexpectedly (issue #96).

ScpClient

• ScpClient.Upload(DirectoryInfo, string) adds extra directory level (issue #128).
• ScpClient.Upload(DirectoryInfo, string) applies timestamp of parent directory (issue #129).

2016.0.0

Changes since 2016.0.0-beta3

Fixes

• Exception if both Password and PrivateKey authentication are tried (issue #55).

Changes since 2013.4.7

Breaking Changes

• Assembly name is now Renci.SshNet for all supported target frameworks.
• The Renci.SshNet assemblies for .NET and Silverlight are now strong-named (CodePlex issue #1802).

New Features

Target framework support

This is the first release of SSH.NET providing support for .NET Core and Universal Windows Platform 10 (UAP10.0). The support for .NET Core comes in the form of an assembly targeting the .NET Platform Standard 1.3 TFM.

The full list of the supported target frameworks for this release is:

• .NET Framework 3.5
• .NET Framework 4.0 (and higher)
• .NET Platform Standard 1.3
• Silverlight 4
• Silverlight 5
• Windows Phone 7.1
• Windows Phone 8.0
• Universal Windows Platform 10

Security

• A given private key file can now be used concurrently.
• Exception message for authentication failures have been improved.
• Added support for ssh.com (SSH-2) private keys (CodePlex issue #1987).
• Support an acceptable group of up to 8192 bits for SHA-1 and SHA-256 Diffie-Hellman Group and Key Exchange (CodePlex issue #1973 and #1777).
• Added support for HMAC-SHA512 (hmac-sha2-512 and hmac-sha2-512-96).

General

• Improved accuracy of IsConnected on .NET.
• Relicensed code under MIT license, explicitly permitting reuse within proprietary software
  provided all copies of the licensed software include a copy of the MIT License terms and the
  copyright notice.
• Separated our hash algorithms into SshNet.Security.Cryptography project and package.
• When available, we prefer hash algorithms and encodings provided by a given target framework above our implementations.

Changes

Performance

Overall performance has been greatly improved. Some of the changes that contributed to these gains are:

• Optimization of payload size for both read and write operations for SftpClient.
• Increase window size from 1 MB to 2 MB.
• Increase default buffer size from 16 KB to 32 KB for SftpClient.
• Take into account the maximum remote packet size of the channel for write operations.
• Increase maximum size of packets that we can receive from 32 KB to 64 KB.
• No longer flush after every SCP write operation (issue #21).
• Do not use reflection to create SSH message instances.
• Eliminate creation and copy of buffers where possible.

Distribution

The SSH.NET NuGet package is now our only binary distribution mechanism.
We no longer provide zip files that contain the assembly for individual target frameworks.

Stop port forwarding

Up to now, stopping a forwarding port would block until all pending requests have completed and all channels are closed. This could result in a serious slowdown when stopping a SshClient with multiple forwarding ports.

As of this release, pending requests will be interrupted and the port will gracefully stop once all channels are closed.

Documentation

Allround improvements to the API documentation.

Exceptions in async methods

Exceptions that are thrown during async processing are no longer wrapped in a SshException.
For example, the following code will now just work:

using (var client = new SftpClient(connectionInfo))
{
    var asyncResult = client.BeginDownloadFile("/home/sshnet/remoteFileThatDoesNotExist", ms);
    ...
    try
    {
        client.EndDownloadFile(asyncResult);
    }
    catch (SftpPathNotFoundException)
    {
        // we should be landing here
    }
}

Fixes

Security

• Exception if both Password and PrivateKey authentication are tried (issue #55).
• Stuck loop on key exchange using arcfour encryption (CodePlex issue #1922).
• No connection possible with the same auth method requested multiple times (CodePlex issue #1930).
• Client cipher is used to decrypt server messages (CodePlex issue #1917).
• Connection dropped by server due to invalid DSA signature (CodePlex issue #1918).
• BlockCipher.Encrypt fails if input message is not padded (CodePlex issue #2547).
• Wrong PKCS7 padding in DES algorithm (CodePlex issue #1580).
• Write access required for private key file
• Stack overflow during authentication when server returns same allowed methods after partial success (CodePlex issue #2399).

SshClient

• Terminal width (pixels) is not passed in pty-req.
• Stopping ForwardedPortDynamic without ever having started would result in a NRE.
• Remove linefeed from WriteLine method in Shellstream class (CodePlex issue #1584).
• SshCommand doesn't cleanup subscribed events (CodePlex issue #2295).
• ShellStream.ReadLine produces incorrect output when reading multi-byte characters (CodePlex issue #3290).
• Forwarded Port channels can get stuck waiting (CodePlex issue #1558).
• Dynamic port forwarding slows down to a crawl (CodePlex issue #2010).
• ForwardedPortDynamic: Unhandled exception if client terminates socket (CodePlex issue #1844).
• Incorrect check for timeout values (CodePlex issue #1620).

SftpClient

• SftpFileStream is very slow (CodePlex issue #1919).
• SftpClient is throwing undocumented exceptions (CodePlex issue #2148).
• SftpClient.Exists(string) returns true for a path that does not exist (CodePlex issue #1952, #1696 and #1574).
• SftpClient constructor throws ArgumentException when host contains underscore (CodePlex issue #1845).
• NullReferenceException when SftpFileStream is finalized after dispose of session (CodePlex issue #2013).
• Partial reads from stream assume end (CodePlex issue #1516).

ScpClient

• No longer flush after every SCP write operation (issue #21).
• Missing files when using DirectoryUpload (CodePlex issue #1382).

General

• Session.Disconnect() hangs forever (CodePlex issue #2591).
• SshData.ReadInt64() is broken (CodePlex issue #2579).
• Race condition when SSH_MSG_GLOBAL_REQUEST is received immediately after successful authentication (issue #8).
• Lines before protocol identification string are not skipped (CodePlex issue #1935 and #2223).
• Disable logging of messages in release builds (CodePlex issue #1767).
• Timeout sending data to server with low window size (CodePlex issue #1706).
• Unobserved exception rethrown by finalizer thread (CodePlex issue #1298 and #1587).
• SendKeepAlive causes SocketException when connection is dropped (CodePlex issue #2029).
• SocketException on Dispose or Disconnect (CodePlex issue #2400).
• Sending EOF on wrong channel number (CodePlex issue #1877).
• HTTP proxy hangs (CodePlex issue #1890).
• Wrong parameters to SetSocketOption leads to SocketException under Mono (CodePlex issue #1799).
• OverflowException on empty server response (CodePlex issue #1562).
• Event handle leak (CodePlex issue #1761).
• Client channels are no longer closed on dispose (CodePlex issue #1943).
• ObjectDisposedException when channel is closing (CodePlex issue #1942 and #1944).
• Signing key is missing from source download (CodePlex issue #2455).
• Correct casing of Security/Cryptography/HMAC.cs to fix build on Linux (CodePlex issue #1505).

2016.0.0-beta3

New Features

.NET Core support

This is the first release of SSH.NET providing support for .NET Core.
The focus for this release was feature completeness and stability.
Future releases will focus on performance.

Changes

Stop port forwarding

Up to now, stopping a forwarding port would block until all pending requests have completed and all channels are closed. This could result in a serious slowdown when stopping a SshClient with multiple forwarding ports.

As of this release, pending requests will be interrupted and the port will gracefully stop once all channels are closed.

Documentation

Allround improvements to the API documentation.

Exceptions in async methods

Exceptions that are thrown during async processing are no longer wrapped in a SshException.
For example, the following code will now just work:

using (var client = new SftpClient(connectionInfo))
{
    var asyncResult = client.BeginDownloadFile("/home/sshnet/remoteFileThatDoesNotExist", ms);
    ...
    try
    {
        client.EndDownloadFile(asyncResult);
    }
    catch (SftpPathNotFoundException)
    {
        // we should be landing here
    }
}

2016.0.0-beta2

Changes:

• Improved performance of ScpClient (GitHub issue #21)

Fixes:

• Terminal width (pixels) is not passed in pty-req
• Stopping ForwardedPortDynamic without ever having started would result in a NRE

2016.0.0-beta1

New Features:

• Added support for HMAC-SHA512 (hmac-sha2-512 and hmac-sha2-512-96)
• Added support for Universal Windows Platform 10 (UAP10.0)

Changes:

• Overall performance improvements
• Relicensed code under MIT license, explicitly permitting reuse within proprietary software
  provided all copies of the licensed software include a copy of the MIT License terms and the
  copyright notice
• Separated our hash algorithms into SshNet.Security.Cryptography project and package
• When available, prefer hash algorithms and encodings from target framework
• Refactoring to prepare for upcoming .NET Core support

Fixes:

• Partial reads from stream assume end (CodePlex issue #1516)
• Session.Disconnect() hangs forever (CodePlex issue #2591)
• SshData.ReadInt64() is broken (CodePlex issue #2579)
• Race condition when SSH_MSG_GLOBAL_REQUEST is received immediately after successful authentication (GitHub issue #8)