> > Hello Nick, > > first of all, thank you for looking into the issue. So please let me ask > this > as a real question and no offence. >
None taken, perfectly fine to ask this. > Why does the project _at all_ use a rather complicated API for > authentication > instead of "outsourcing" the function into a simple called hook (call it a > script), and let this implement the wanted api to ldap, mysql, radius or > just > about anything that might be needed. This is what we already do. Yes, the entire web-based application works through a REST API, but, on the back-end, we take the REST API calls and feed them, through a set of standard interfaces, to a back-end authentication mechanism. The back-end authentication mechanisms are standardized, interchangeable and stackable - you can use one or more in combination, or you can write your own. The mechanisms can also "decorate" other ones, so that you can use a back-end mechanism (like JDBC), but extend its functionality to do something else. > Still in the end an authentication is no > more than giving parameters (like username, password, or client ip or > whatever the caller (i.e. guacamole) has) and getting the simple answer: > yes > (authenticated) or no (login failed). > This is really what the REST API does - it allows the front-end web application to 1) receive a list of requirements from the back-end authentication mechanism, 2) provide those requirements, either automatically (client IP) or by user input (username and password), 3) get an answer about whether authentication has succeeded or not, and 4) receive and process data that the client has been authorized to receive (in our case, connections, connection groups, users, groups, etc.). > If you cut off the whole process at this point the whole story gets a lot > more > flexible, as anyone can then implement his needed hook (script) for his > needs. > As mentioned above, this is exactly how it works with the authentication extensions. > You may then distribute such hooks inside the project for standard APIs > like > ldap or the like - or leave it to the users to make/find their own. > Yep, and Guacamole's design allows for exactly this - and the REST API does not get in the way of that, in fact, it makes it possible to do that without having to change the front-end web application at all. Also, none of the things you've mentioned actually address the issue you've originally raised - no matter what method you use to communicate between the web browser and the server, you still need to be able to provide the data you're interested in providing - IP address, username, and password - to the authentication system (LDAP you specifically mentioned). Unless your solution is to have the client authenticate to LDAP directly and then somehow tell the server that it is authenticated - which has a lot of security risks to it (how does the server know to trust the client when it says it authenticated successfully?) - I don't know of a way, with *LDAP* specifically, to have the client IP address be part of the authentication process, regardless of the language (PHP, ldapsearch, Java/JSP, CGI/Perl...etc.). RADIUS, as a protocol, has those things built into it - the NAS IP field within a RADIUS authentication request allows you to pass the client IP on to the RADIUS server and then allow the RADIUS server to make a determination about authentication success or failure based on that in combination with the other information asked and provided (RADIUS secret, username, password, one-time-password, etc.). So does Kerberos - in fact, Kerberos actually does exactly what is mentioned above - establishes a trusted relationship between KDC, Server/Service, and Client, such that the client can authenticate and then reliably tell the server that it should trust the client because they share information that makes it trustworthy. And so Kerberos also has a way of factoring the client system into the authentication process, in addition to the username and password. At some point I will probably take a crack at a Kerberos extension or configuration that does this, which also allows for doing very seamless authentication with no need for entering credentials if you're already logged into a client where you have a valid Kerberos ticket. If you're also just looking for a way to factor a client IP address into the authentication process, but it doesn't have to be linked directly to the username or password, there are ways to do that, as well: * Have a front-end proxy or Web Application Firewall filter based on IP address. * The 1.6.0 version of Guacamole Client will have an extension that allows for banning IP addresses that repeatedly fail authentication. This can be done, today, using something like fail2ban, but it'll be a bit more integrated and easy with the extension. * Write another authentication extension that either allows or disallows authentication based on IP address or CIDR range. * The guacamole-auth-header extension also allows you to perform your authentication using some other means - like a front-end web proxy (Nginx or httpd) and then provide a way to pass that authentication information through to Guacamole in such a way that Guacamole trusts that the username being provided has actually been authenticated. This also might help accomplish something closer to the original goal - for example, you could put Apache httpd in front of Guacamole, configure httpd to do LDAP authentication but also configure it with certain allowed and/or denied IP addresses or IP ranges, and then use the guacamole-auth-header extension. -Nick
