known_users

This is a really simple package to read and parse known_users files. This can be useful when you want to verify that the SSH host you are talking to is legitimate.

Usage

var known_hosts = require('known_hosts');

var keys = known_hosts.parseKnownHostsFile();
...
var connectionOptions = {
	    hostHash: 'sha1',
		  checkHostValid: function (serverKeyHash) {
        var valid = false;
        keys.forEach(function (k) {
          if (k.hostCheck(remoteHost) && someSecurityFunction(remoteHost, serverKeyHash)) valid = true;
        });
        return valid;
      }
}

Running the parseKnownHostsFile without any arguments will try to use the known hosts file under your user directory (~/.ssh/known_hosts). You can also pass it a file path to another file, or a string to be parsed.

Key Types

This module handles both encrypted and unencrypted keys. If the 'HashKnownHosts' option in either /etc/ssh/ssh_config or ~/.ssh/config is set to 'Yes', your hosts file will be encrypted. The salt is stored in the known_hosts file, so we can verify against it. Until the correct IP or hostname is provided, there's no way to know what that host points to. This is generally a good idea, since it makes attacking hosts in your known_hosts file harder if an attacker gets control of your computer.

Questions, comments, concerns?

Let me know if there's an issue or something you'd like added. I wrote this as a quick and easy way to check hosts while using the ssh2 npm module. I wrote known_hosts this morning, so there may be bugs.