Connection Tunneling via Command-Line options / Passphrase for private key :: Support Forum

p-st Donor
Joined:: 2016-07-08
Posts:: 11

Connection Tunneling via Command-Line options / Passphrase for private key

2021-09-23 13:53

Hi!

I'm launching a WinSCP session via command-line options, which works great! Now I want to launch a WinSCP session, which uses a SSH tunnel. I managed to do it with the Raw Site Settings "Tunnel*". I would have one feature request - it would be nice if there would be an option for setting the passphrase for the private key, e.g. with a new option TunnelPassphrase, like it is already available in the command-line options for the session (/privatekey and /passphrase). Would this be possible?

Another thing I stumbled upon is the option TunnelPublicKeyFile, which stands for the private key. It is no big deal but why isn't it called "TunnelPrivateKeyFile"?

Thanks for the great work!

Regards
Patrick

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martin◆ Site Admin
Joined:: 2002-12-10
Posts:: 41,518
Location:: Prague, Czechia

Re: Connection Tunneling via Command-Line options / Passphrase for private key

2021-09-24

I cannot test right now, but I believe that the -passphrase would be used even for tunnel.

Regarding the PublicKeyFile: Some of registry settings names, including this one, are inherited from PuTTY. I do not know why they chose this name.

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p-st Donor

2021-09-24 08:22

Thanks for your answer!

If the session passphrase can be used for the private key of the tunnel, then how can I set separate passphrases in case there is a different private key with a different passphrase for the session and the tunnel?

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martin◆ Site Admin

2021-09-27

You cannot. But in general, what prevents you from using the same passphrase for both? You can even use the same private key for both servers.

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p-st Donor
Joined:: 2016-07-08
Posts:: 11

2021-09-27 17:08

Ok, I agree. But even when the private keys have the same passphrase, you'll have to manually enter the passphrase for the tunnel key. I made a test with two different private keys. Both have the same passphrase:

Command-line:

"C:\WinSCP\WinSCP.exe" scp:ec2-user@10.16.35.7:22/home/ec2-user/ /privatekey=D:\my_private_key.ppk /passphrase=*** /rawsettings Tunnel=1 TunnelLocalPortNumber=0 TunnelHostName=my_jumphost TunnelPortNumber=22 TunnelUserName=tunnel_username TunnelPasswordPlain=*** TunnelPublicKeyFile=my_tunnel_private_key.ppk

WinSCP will ask the user to enter the passphrase for the tunnel. After entering the passphrase manually, the session will open up without a prompt. So I think the option /passphrase is ignored by the Tunnel feature.

When using plink, it works without a prompt at all, because plink will accept -pw as passphrase:

Command-line:

"C:\WinSCP\WinSCP.exe" scp:ec2-user@10.16.35.7:22/home/ec2-user/ /privatekey=D:\my_private_key.ppk /passphrase=*** /rawsettings ProxyMethod=5 ProxyTelnetCommand="""C:\\PuTTY\\plink.exe"" -P 22 -l tunnel_username my_jumphost -nc 10.16.35.7:22 -i ""my_tunnel_private_key.ppk"" -pw "***""

So using the native WinSCP tunneling feature, I think there is no way to suppress the passphrase prompt for the private key of the tunnel (except of course if you use pageant).

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martin◆ Site Admin
Joined:: 2002-12-10
Posts:: 41,518
Location:: Prague, Czechia

2021-09-29

You are right.

I have added this issue to the tracker:
Issue 2029 – Allow providing tunnel private key passphrase in scripting

I'm sending you an email with a development version of WinSCP to the address you have used to register on this forum.

Use TunnelPassphrasePlain raw session settings.

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p-st Donor

2021-09-29 16:50

I can confirm that – using the development version of WinSCP – it is now possible to set the passphrase for the tunnel key via command-line raw setting TunnelPassphrasePlain, so that the session will open up without the passphrase prompt. Thank you very much!

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