SQL Server

SSH Tunnel Authenticate with a SecureString Password

Demonstrates the Chilkat SshTunnel.AuthenticateSecPw method, which authenticates using SecureString login and password objects. The first argument is the login and the second is the password.

Background: Because a tunnel process is long-lived and holds its SSH credentials for its entire lifetime, protecting them in memory is worthwhile. A SecureString keeps the value encrypted under a randomly generated session key. Populate it from a value obtained at runtime rather than a hard-coded literal.

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-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    --  Demonstrates the SshTunnel.AuthenticateSecPw method, which authenticates using SecureString
    --  login and password objects.  The 1st argument is the login and the 2nd is the password.

    DECLARE @tunnel int
    EXEC @hr = sp_OACreate 'Chilkat.SshTunnel', @tunnel OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    --  The tunnel forwards accepted local connections to this destination through the SSH server.
    EXEC sp_OASetProperty @tunnel, 'DestHostname', 'db.internal.example.com'
    EXEC sp_OASetProperty @tunnel, 'DestPort', 5432

    --  Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
    --  does not authenticate yet.
    DECLARE @sshPort int
    SELECT @sshPort = 22
    EXEC sp_OAMethod @tunnel, 'Connect', @success OUT, 'ssh.example.com', @sshPort
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    --  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.
    DECLARE @password nvarchar(4000)
    SELECT @password = 'mySshPassword'

    --  Place the login and password into SecureString objects.
    DECLARE @secureLogin int
    EXEC @hr = sp_OACreate 'Chilkat.SecureString', @secureLogin OUT

    EXEC sp_OAMethod @secureLogin, 'Append', @success OUT, 'mySshLogin'
    DECLARE @securePassword int
    EXEC @hr = sp_OACreate 'Chilkat.SecureString', @securePassword OUT

    EXEC sp_OAMethod @securePassword, 'Append', @success OUT, @password

    EXEC sp_OAMethod @tunnel, 'AuthenticateSecPw', @success OUT, @secureLogin, @securePassword
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @secureLogin
        EXEC @hr = sp_OADestroy @securePassword
        RETURN
      END

    PRINT 'Authenticated with secure strings.'

    --  After authenticating, call BeginAccepting to start listening for local connections to forward.

    DECLARE @waitForThreadExit int
    SELECT @waitForThreadExit = 1
    EXEC sp_OAMethod @tunnel, 'CloseTunnel', @success OUT, @waitForThreadExit
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        EXEC @hr = sp_OADestroy @secureLogin
        EXEC @hr = sp_OADestroy @securePassword
        RETURN
      END

    EXEC @hr = sp_OADestroy @tunnel
    EXEC @hr = sp_OADestroy @secureLogin
    EXEC @hr = sp_OADestroy @securePassword


END
GO