B4X

Start SSH Tunnel Keyboard-Interactive Authentication

Demonstrates the Chilkat SshTunnel.StartKeyboardAuth method, which begins keyboard-interactive authentication. The only argument is the login name. It returns XML describing the server's prompts, which are answered with ContinueKeyboardAuth.

Background: Keyboard-interactive is the prompt-driven authentication method: the server sends one or more questions — a password, a one-time code, a security question — and the client answers each. This is how a tunnel supports two-factor and other challenge-response schemes. The returned XML says exactly what to ask and whether to mask the input.

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Dim success As Boolean = False

'  Demonstrates the SshTunnel.StartKeyboardAuth method, which begins keyboard-interactive
'  authentication.  The only argument is the login name.  It returns XML describing the server's
'  prompts, which are answered with ContinueKeyboardAuth.

Dim tunnel As ChilkatSshTunnel
tunnel.Initialize("tunnel")

'  The tunnel forwards accepted local connections to this destination through the SSH server.
tunnel.DestHostname = "db.internal.example.com"
tunnel.DestPort = 5432

'  Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
'  does not authenticate yet.
Dim sshPort As Int = 22
success = tunnel.Connect("ssh.example.com", sshPort)
If success = False Then
    Log(tunnel.LastErrorText)
    Return
End If


'  Begin keyboard-interactive authentication.  The returned XML describes the server's prompts.
Dim infoRequestXml As String = tunnel.StartKeyboardAuth("mySshLogin")
If tunnel.LastMethodSuccess = False Then
    Log(tunnel.LastErrorText)
    Return
End If

Log(infoRequestXml)

'  Answer the prompt(s) with ContinueKeyboardAuth, then call BeginAccepting.

Dim waitForThreadExit As Boolean = True
success = tunnel.CloseTunnel(waitForThreadExit)
If success = False Then
    Log(tunnel.LastErrorText)
    Return
End If