Added SshCommand.InputStream to allow writing to stdin of SshCommand

[realvizu]

Changes:

• Added SshCommand.InputStream (type: ChannelInputStream), which sends the data written to the stream through a command's channel.
• Added an integration test that echos back the sent data using the "cat" command.
• All unit tests pass.

I you have recommendations for further unit tests, please advise.

---

I started the work by trying to run all unit tests on my dev machine to see if they all pass. Unfortunately a lot of them failed, so I had to make the following modifications (see the changes in my first commit in this PR):

• Excluded MD5 tests for the net462 target, because I got System.InvalidOperationException: 'This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms.'
• Modified SshdConfig.cs: do not throw for "Include", just do nothing.
• Modified failing dos2unix parameters in Dockerfile.TestServer.
• Added a line to .gitattributes to force LF line ending for key files used by integration tests, otherwise using them causes error.
• Modified SftpClientTest.Test_Sftp_Multiple_Async_Upload_And_Download_10Files_5MB_Each to upload only 2 files instead of 10 because for more than 2 files I got timeout errors.

If you know a better fix for any of the above modifications, please advise.

[WojciechNagorski]

It looks good to me! But I need more time to test it!

Do you have a specific function in mind that you want to implement using this functionality? Did you see that it can be useful in https://github.com/dotnet/Docker.DotNet/issues/540

[WojciechNagorski]

Those tests work on my machine.

[realvizu]

It looks good to me! But I need more time to test it!

Do you have a specific function in mind that you want to implement using this functionality? Did you see that it can be useful in dotnet/Docker.DotNet#540

I had a very specific use case: I had to call some legacy system that is implemented as a set of SSH commands and one of the commands requires sending a file via input stream. These changes made it work.

[realvizu]

Thanks a lot @WojciechNagorski and @Rob-Hague for the comments and suggestions!

• I reverted all the FIPS-related changes and the change made to SftpClientTest.Upload.cs.
• I moved the EOF sending to Dispose and added a unit test that validates that now multiple calls to Write works as expected.
• I've adapted @Rob-Hague 's suggestion about making InputStream lazily initialized with some modification. I wanted to make it more apparent that a resource is created here (that should be disposed after using), so I changed the InputStream from a property to a CreateInputStream method.
• Also, because the input stream uses the channel created in BeginExecute and closed in EndExecute, I added a check that throws invalid operation exception if CreateInputStream is called when there's no channel to use. Also added some unit tests for this.

[realvizu]

Shall I do a squash+rebase onto develop before merging the PR?

[Rob-Hague]

It will be merged with "Squash and merge" so it is not necessary

(it requires a CODEOWNERS approval before it can merge)

[WojciechNagorski]

There is a build problem:

C:\projects\ssh-net\test\Renci.SshNet.IntegrationTests\SshClientTests.cs(37,33): error CS7036: There is no argument given that corresponds to the required parameter 'offset' of 'Stream.Write(byte[], int, int)' [C:\projects\ssh-net\test\Renci.SshNet.IntegrationTests\Renci.SshNet.IntegrationTests.csproj::TargetFramework=net48]

[WojciechNagorski]

This issue has been fixed in the 2024.0.0 version.