"Data longer than 2147483647 is not supported" exception when connecting to Tectia ssh server running on a mainframe

[edmlin]

This is similar to issue #41 but not exactly the same.
When connecting to Tectia ssh server running on a mainframe, I intermittently got an exception: Data longer than 2147483647 is not supported.
Tracing into the code I found that it looks like sometimes the first 4 bytes in the SSH_MSG_IGNORE message are filled with arbitrary numbers instead of the actual data length. When the number is greater than int.MaxValue the exception is thrown.
Changing IgnoreMessage.LoadData to the following fixed the issue:

        protected override void LoadData()
        {
            var dataLength = ReadUInt32();
            if (dataLength > (DataStream.Length - DataStream.Position))
            {
                DiagnosticAbstraction.Log("SSH_MSG_IGNORE: Length exceeds data bytes, data ignored.");
                Data = Array<byte>.Empty;
            }
            else if (dataLength > int.MaxValue)
            {
                throw new NotSupportedException(string.Format(CultureInfo.CurrentCulture, "Data longer than {0} is not supported.", int.MaxValue));
            }
            else
            {
                Data = ReadBytes((int) dataLength);
            }
        }

The server version says "SSH-2.0-4.3.6500.1 SSH Secure Shell".

[drieseng]

@edmlin Would it be possible to contact Tectia, and ask them whether this is a know issue? I'm ok with adding targeted workarounds, but for this to happen we need to be able to uniquely identify the SSH (server) software and version to which the workaround applies.

[edmlin]

I can't get a confirmation from Tectia.
The change in above post only swaps the 2 abnormal condition handling and protect clients from malformed messages. I don't think there will be any negative effect. Maybe there's a better way to do it. I hope this can be addressed in this repo so in the future when I upgrade to a newer version my app won't break.
Thanks.

[dinehs]

Hi Edmin,

Do you have any workarounds of this issues.
I am used the latest ssh.net 2020 version, but still the issue persist again.

Thanks,
Dinesh

[edmlin]

Yes my workaround is the code change I mentioned above in file src/Renci.SshNet/Messages/Transport/IgnoreMessage.cs.

[dinehs]

Hi Edmin, Thanks for your reply. You mean to download the source code of this library "Renci.ssh" and do that change what you mentioned on that post right?. Thanks, Dinesh

…

On Thu, 7 Jan, 2021, 8:42 pm edmlin, ***@***.***> wrote: Yes my workaround is the code change I mentioned above in file src/Renci.SshNet/Messages/Transport/IgnoreMessage.cs. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#713 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ASMHZSDKQ756RLHBYU4XOVLSYXFNNANCNFSM4POS7GPA> .

[edmlin]

Yes. Then you can build a DLL from the modified source code or include the project to you solution.

[dinehs]

Thank you Edmin.

…

On Thu, 7 Jan, 2021, 9:34 pm edmlin, ***@***.***> wrote: Yes. Then you can build a DLL from the modified source code or include the project to you solution. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#713 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ASMHZSGQOGAAITXEYSUN7XLSYXLQDANCNFSM4POS7GPA> .

[dinehs]

Hi Drieseng,

Do you have any plan to fix the issue for the upcoming release?.

Thanks,
Dinesh

[drieseng]

@edmlin @dinehs Are you both using (the same version of) "Tectia ssh server"?

[dinehs]

Hi Drisen, I am not sure about the sever but we are connecting mainframe there only getting this issue. And we connecting another SFTP server which is not mainframe it got connected without issues. Thanks, Dinesh

…

On Sat, 9 Jan, 2021, 6:57 pm Gert Driesen, ***@***.***> wrote: @edmlin <https://github.com/edmlin> @dinehs <https://github.com/dinehs> Are you both using (the same version of) "Tectia ssh server"? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#713 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ASMHZSGOH7BMK4ZQMQHPQXLSZBKSNANCNFSM4POS7GPA> .

[dinehs]

Hi, I am working on file upload to mainframe that is mainframe dataset. The issues when I upload with the specified command "/FTADV:P=WIN" for dataset file to mainframe the .net cursor will not come out the upload function of ssh.net ,that looks waiting for some response from server I guess. Do you have any fix for that issue? Thanks, Dinesh On Sat, 9 Jan, 2021, 11:53 pm dinesh k, <dinesh.kaliyamoorthy@gmail.com> wrote:

…

Hi Drisen, I am not sure about the sever but we are connecting mainframe there only getting this issue. And we connecting another SFTP server which is not mainframe it got connected without issues. Thanks, Dinesh On Sat, 9 Jan, 2021, 6:57 pm Gert Driesen, ***@***.***> wrote: > @edmlin <https://github.com/edmlin> @dinehs <https://github.com/dinehs> > Are you both using (the same version of) "Tectia ssh server"? > > — > You are receiving this because you were mentioned. > Reply to this email directly, view it on GitHub > <#713 (comment)>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/ASMHZSGOH7BMK4ZQMQHPQXLSZBKSNANCNFSM4POS7GPA> > . >

[jglazer63]

Is there any way we can get this compiled into the nuget package? My company will not allow me to download source or bring in "unknown" software. Nuget is fine though.

[WojciechNagorski]

The 2023.0.1 version has been released to Nuget: https://www.nuget.org/packages/SSH.NET/2023.0.1