Objective-C

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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Objective-C

#import <CkoSshTunnel.h>
#import <NSString.h>
#import <CkoSecureString.h>

BOOL success = NO;

//  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.

CkoSshTunnel *tunnel = [[CkoSshTunnel alloc] init];

//  The tunnel forwards accepted local connections to this destination through the SSH server.
tunnel.DestHostname = @"db.internal.example.com";
tunnel.DestPort = [NSNumber numberWithInt:5432];

//  Connect to the SSH server.  This performs the TCP/proxy connection and SSH handshake, but
//  does not authenticate yet.
int sshPort = 22;
success = [tunnel Connect: @"ssh.example.com" port: [NSNumber numberWithInt: sshPort]];
if (success == NO) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

//  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.
NSString *password = @"mySshPassword";

//  Place the login and password into SecureString objects.
CkoSecureString *secureLogin = [[CkoSecureString alloc] init];
[secureLogin Append: @"mySshLogin"];
CkoSecureString *securePassword = [[CkoSecureString alloc] init];
[securePassword Append: password];

success = [tunnel AuthenticateSecPw: secureLogin password: securePassword];
if (success == NO) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

NSLog(@"%@",@"Authenticated with secure strings.");

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

BOOL waitForThreadExit = YES;
success = [tunnel CloseTunnel: waitForThreadExit];
if (success == NO) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}