Java™ Application Development on Linux - Dator

20.3 Be an Enabler, or “Let’s Be Codependent!”445Up to this point, we have largely been considering a situation where theJava developer is working on an individual workstation where he or she hasroot access. Now that we are talking about application servers, we are dealingwith systems where, as the software progresses from development throughrounds of testing to production, we will want to limit the people who are ableto change certain elements of the system. Often, the “quick and dirty” strategyis to share out the root password to a number of users. This is a serious securityrisk, even when all parties are trusted. Why? Because root isn’t a person. Whensomeone logs in as root, we do not know who that person is. We only knowthat it is someone who knows the root password. In some businesses, this isan unacceptable ambiguity in audit.A common alternative is to restrict root login to the console only, and torequire the use of the su (“set user”) command to promote an already loggedinuser to root status. This provides a link back to the individual, so actionscan be traced to single person. That improves auditability.This strategy is better, but since root is an all-or-nothing proposition, itis a fairly blunt instrument. Once someone can su to root, that someone cando anything. That’s a lot of power to give to someone who just needs to be ableto install WAR files.Yet another strategy is to set up the sudo system. 4 Using sudo, you canspecify what people can execute which commands as root, and where they maydo it from. In other words, you might let user alice start and stop the Webserver and mount and unmount filesystems when she is logged in to a localmachine, but only to start the Web server when she is logged in on a machineoutside your network. Check out the manpage for sudo to learn more. Eventhis isn’t the best solution for the present issue.The best solution is not to require root power at all if you can avoid it.Remember that permissions on files in Linux are assigned to users, groups, andothers. Most people do not think about the middle tier, groups. But groups arethe best way to give control over parts of the filesystem to a collection of userswithout requiring them to share an account and password.20.3.1 Nonroot-Installed SoftwareThe problem with all of the power-sharing strategies we outlined earlier is thatonce the user escalates to root, there is no way to limit what he or she can do4. Some folks pronounce this “ess-you doo,” and some “pseudo.” Whatever floats your boat.