Tcl

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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Tcl


load ./chilkat.dll

set success 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.

set tunnel [new_CkSshTunnel]

#  The tunnel forwards accepted local connections to this destination through the SSH server.
CkSshTunnel_put_DestHostname $tunnel "db.internal.example.com"
CkSshTunnel_put_DestPort $tunnel 5432

#  Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
#  does not authenticate yet.
set sshPort 22
set success [CkSshTunnel_Connect $tunnel "ssh.example.com" $sshPort]
if {$success == 0} then {
    puts [CkSshTunnel_lastErrorText $tunnel]
    delete_CkSshTunnel $tunnel
    exit
}

#  Begin keyboard-interactive authentication to receive the server's prompt(s).
set infoRequestXml [CkSshTunnel_startKeyboardAuth $tunnel "mySshLogin"]
if {[CkSshTunnel_get_LastMethodSuccess $tunnel] == 0} then {
    puts [CkSshTunnel_lastErrorText $tunnel]
    delete_CkSshTunnel $tunnel
    exit
}

#  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.
set password "mySshPassword"

#  Submit the response (typically the password).  The returned XML indicates the next prompt or
#  the final result.
set result [CkSshTunnel_continueKeyboardAuth $tunnel $password]
if {[CkSshTunnel_get_LastMethodSuccess $tunnel] == 0} then {
    puts [CkSshTunnel_lastErrorText $tunnel]
    delete_CkSshTunnel $tunnel
    exit
}

puts "$result"

set waitForThreadExit 1
set success [CkSshTunnel_CloseTunnel $tunnel $waitForThreadExit]
if {$success == 0} then {
    puts [CkSshTunnel_lastErrorText $tunnel]
    delete_CkSshTunnel $tunnel
    exit
}


delete_CkSshTunnel $tunnel