Xbase++

Continue SSH Tunnel Keyboard-Interactive Authentication

Demonstrates the Chilkat SshTunnel.ContinueKeyboardAuth method, which submits a response to a keyboard-interactive prompt. The only argument is the response text; for a request with multiple prompts, an XML response is supplied instead. It returns XML indicating the next prompt or the final result.

Background: This is the second half of the exchange started by StartKeyboardAuth. A server may issue several rounds of prompts, so a robust client loops: submit answers, read the returned XML, and continue until it sees success or failure. On success, BeginAccepting still must be called before the tunnel forwards traffic.

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LOCAL nSuccess
LOCAL oTunnel
LOCAL nSshPort
LOCAL cInfoRequestXml
LOCAL cPassword
LOCAL cResult
LOCAL nWaitForThreadExit

nSuccess := 0

//  Demonstrates the SshTunnel.ContinueKeyboardAuth method, which submits a response to a
//  keyboard-interactive prompt.  The only argument is the response.  For multiple prompts, an XML
//  response is supplied instead.

oTunnel := CreateObject("Chilkat.SshTunnel")

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

//  Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
//  does not authenticate yet.
nSshPort := 22
nSuccess := oTunnel:Connect("ssh.example.com", nSshPort)
IF (nSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    RETURN
ENDIF

//  Begin keyboard-interactive authentication to receive the server's prompt(s).
cInfoRequestXml := oTunnel:StartKeyboardAuth("mySshLogin")
IF (oTunnel:LastMethodSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    RETURN
ENDIF

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
cPassword := "mySshPassword"

//  Submit the response (typically the password).  The returned XML indicates the next prompt or
//  the final result.
cResult := oTunnel:ContinueKeyboardAuth(cPassword)
IF (oTunnel:LastMethodSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    RETURN
ENDIF

? cResult

nWaitForThreadExit := 1
nSuccess := oTunnel:CloseTunnel(nWaitForThreadExit)
IF (nSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    RETURN
ENDIF

oTunnel:destroy()