Objective-C

SSH Tunnel Authenticate with a SecureString Password and Private Key

Demonstrates the Chilkat SshTunnel.AuthenticateSecPwPk method, which authenticates using SecureString login and password objects together with a private key. The third argument is the SshKey private key.

Note: The private-key path is relative to the application's current working directory. Absolute paths may also be used. Supply the path to your own key file.

Background: This is the SecureString form of two-factor tunnel authentication: the password is held encrypted in memory and combined with a private key for servers that require both. It is the most protective option when a deployment mandates two-factor SSH and you also want to minimize plaintext credential exposure in a long-running process.

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Objective-C

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

BOOL success = NO;

//  Demonstrates the SshTunnel.AuthenticateSecPwPk method, which authenticates using SecureString
//  login and password objects together with a private key.  The 1st argument is the username, the
//  2nd is the password, and the 3rd is an SshKey private key.

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";

//  Load the SSH private key.  LoadText reads the file's text, which is then imported.
CkoSshKey *privKey = [[CkoSshKey alloc] init];
NSString *keyText = [privKey LoadText: @"qa_data/id_rsa"];
if (privKey.LastMethodSuccess == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

success = [privKey FromOpenSshPrivateKey: keyText];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

//  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 AuthenticateSecPwPk: secureLogin password: securePassword privateKey: privKey];
if (success == NO) {
    NSLog(@"%@",tunnel.LastErrorText);
    return;
}

NSLog(@"%@",@"Authenticated.");

//  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;
}