Support keyboard-interactive authentication

[drieseng]

Fix support for keyboard-interactive authentication by:

• using PAM-enabled version of OpenSSH
• using chage to force expiry of password

In TearDown() of AuthenticationTests, correctly reset state of docker container by changing the password of the sshnet user back to the default value and removing its password expiration.

Fixes #2.

Note:
You'll need to update SshNet.TestTools.OpenSSH.

[IgorMilavec]

The KeyboardInteractive_PasswordExpired still fails, now the test result is:

  Message: 
Test method SshNetTests.AuthenticationTests.KeyboardInteractive_PasswordExpired threw exception: 
Renci.SshNet.Common.SshAuthenticationException: Permission denied (keyboard-interactive).

  Stack Trace: 
ClientAuthentication.Authenticate(IConnectionInfoInternal connectionInfo, ISession session)
ConnectionInfo.Authenticate(ISession session, IServiceFactory serviceFactory)
Session.Connect()
BaseClient.CreateAndConnectSession()
BaseClient.Connect()
AuthenticationTests.KeyboardInteractive_PasswordExpired() line 285

The password is correctly reset and other tests can continue.

[drieseng]

Hmm, it consistently passes here.
Few questions:

1. Does it fail when you only run that test?
2. Does it fail when you only run the tests in AuthenticationTests?
3. Do you run the tests in Visual Studio or command-line?

[IgorMilavec]

I've just observed that it only fails the first time after I run the container. If I repeat the test without restarting the container, it passes.

[IgorMilavec]

Running _remoteSshdConfig?.Reset() from SetUp() fixes this. It seems that the config in the container differs from what Reset() generates.

[drieseng]

@IgorMilavec The default config indeed differs. Ideally, we'd generate the default config using the same mechanism.
For now, I'll just fix the tests to set UsePAM to true.
I'll update the PR later today.

[drieseng]

@IgorMilavec, this should do it.

[IgorMilavec]

Great, KeyboardInteractive_PasswordExpired now passes the first time.

[drieseng]

@IgorMilavec Please re-review.

[IgorMilavec]

Great solution with the prune batch, now it's under user's control.