ssh client freezes with output redirection to stdin of Linux server....

[naatje80]

Please answer the following

If it is a terminal issue then please go through wiki
https://github.com/PowerShell/Win32-OpenSSH/wiki/TTY-PTY-support-in-Windows-OpenSSH

"OpenSSH for Windows" version
v0.0.22.0

Server OperatingSystem
Scientific Linux 6.9

Client OperatingSystem
Windows 10 Enterprise

What is failing
When forwarding text to stdin to Linux server running ssh-daemon, the ssh client on windows freezes. I've both tried following command both in the powershell and the Windows command line, but the results are the same:
Powershell:
echo "Hello World"|./ssh user@server "cat -"

Expected output
Hello World
Return to command line.

Actual output
Hello World
Client freezes.

[naatje80]

Forgot to mention i could stop the client by typing Control+C.

[manojampalam]

Can you check if the session process (sshd) is still running on your Linux target? It looks like the client is hanging as the channel from target is still open.

[naatje80]

Dear manojampalam,

Thank you for your reply. The session process is indeed still running on the Linux target. When break the client session by pressing Control+C it is also closed.

[manojampalam]

@naatje80 can you also confirm that the shell process (that is executing cat -) is still running?

If so, that would be the root cause why ssh.exe isn't exiting. You can expect the following to be sent to your shell process - "Hello World"\r\n
Do you expect the shell process to continue running with that input?

[naatje80]

The cat process is indeed still running on the server.

What I actually wanted to achieve is copying the public ssh key added to the authorized keys of a file using ssh. But because the client freezes, I tried just the basic: only redirecting some text to the remote server.

What I see is that if I send output to the stdin using ssh, the file is created but the content is not added until I press Control+C. I also tried the redirection using dd:
echo "Hello World"\r\n | ssh userid@server "dd of=some_file oflag=append conv=notrunc"
I see the same issue: dd is not closing on the server side until I press Control+C in the client. Also the file is created but the content is not added until Control+C is pressed in the ssh client on the Windows side.

I already tried various carriage return ending for the echo line, because I also expected that it was waiting a return. But none seem to help.

Hopefully this additional information is helpfull.....

[manojampalam]

OK Thanks. Found the issue. Will fix it for next release.

[manojampalam]

Try the attached private.
ssh.zip

[naatje80]

Great, thank you! The issue is indeed now solved. There was only one issue with the ssh.exe you've supplied, It had a dependency for libcrypto.dll but the pre-compiled version of the full package contained a file called libcrypto-41.dll (Only had to copy and rename that file to use the ssh.exe). But this is most likely due to the way you've compiled the pacakge.....

[bagajjal]

@naatje80 - We are renaming the dll to exclude the version number so the new release (yet to be released) will have libcryto.dll instead of libcrypto-41.dll.