Paranoid Penguin - Introduction to SELinux, Part II
The comprehensive “deny-by-default” policy originally developed for Fedora Core 2, called strict, is still maintained for RHEL, Fedora and CentOS, and it can be installed instead of targeted. However, strict is not officially (commercially) supported in RHEL due to its complexity. On most systems, this policy takes a lot of manual tweaking, both by editing the files in /etc/selinux and by using the standard SELinux commands chcon, checkpolicy, getenforce, newrole, run_init, setenforce and setfiles.
Note that Tresys (www.tresys.com) maintains a suite of free, mainly GUI-based, SELinux tools that are a bit easier to use, including SePCuT, SeUser, Apol and SeAudit. These are provided by RHEL's setools RPM package. Note also that on non-Red-Hat-derived Linux distributions, SELinux policies usually reside in /etc/security/selinux.
To customize and use the strict policy on RHEL 4, see Russell Coker's tutorial “Introduction to SELinux on Red Hat Enterprise Linux 4” (see Resources). You need to install the package selinux-policy-strict, available in Fedora's rawhide repository (the selinux-policy-strict package in Fedora Core 5 or 6 may also work in RHEL 4).
It's also possible, of course, to develop and enable your own SELinux policies from scratch, though doing that is well beyond the scope of this article. In fact, entire books have been written on this topic. See Resources for information on SELinux policy creation and customization.
And with that, I hope you're off to a good start with SELinux. Be safe!
Resources
Faye and Russell Coker's article “Taking advantage of SELinux in Red Hat Enterprise Linux”: www.redhat.com/magazine/006apr05/features/selinux
McCarty, Bill. SELinux: NSA's Open Source Security Enhanced Linux. Sebastopol, CA: O'Reilly Media, 2005. Definitive resource, but predates Red Hat and Fedora's implementation of targeted and strict policies.
Mayer, Frank, Karl MacMillan and David Caplan. SELinux by Example: Using Security Enhanced Linux. Upper Saddle River, NJ: Prentice Hall, 2007. Brand-new book, by several SELinux contributors.
Chad Hanson's paper “SELinux and MLS: Putting the Pieces Together”: selinux-symposium.org/2006/papers/03-SELinux-and-MLS.pdf
“Red Hat Enterprise Linux 4: Red Hat SELinux Guide”: www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/selinux-guide/index.html
Russell Coker's tutorial “Introduction to SELinux on Red Hat Enterprise Linux 4”: www.coker.com.au/selinux/talks/rh-2005/rhel4-tut.html
Mick Bauer (darth.elmo@wiremonkeys.org) is Network Security Architect for one of the US's largest banks. He is the author of the O'Reilly book Linux Server Security, 2nd edition (formerly called Building Secure Servers With Linux), an occasional presenter at information security conferences and composer of the “Network Engineering Polka”.
- « first
- ‹ previous
- 1
- 2
- 3
Realizing the promise of Apache® Hadoop® requires the effective deployment of compute, memory, storage and networking to achieve optimal results. With its flexibility and multitude of options, it is easy to over or under provision the server infrastructure, resulting in poor performance and high TCO. Join us for an in depth, technical discussion with industry experts from leading Hadoop and server companies who will provide insights into the key considerations for designing and deploying an optimal Hadoop cluster.
Sponsored by AMD
Built-in forensics, incident response, and security with Red Hat Enterprise Linux 6
Every security policy provides guidance and requirements for ensuring adequate protection of information and data, as well as high-level technical and administrative security requirements for a system in a given environment. Traditionally, providing security for a system focuses on the confidentiality of the information on it. However, protecting the data integrity and system and data availability is just as important. For example, when processing United States intelligence information, there are three attributes that require protection: confidentiality, integrity, and availability.
Learn more about catching the bad guy in this free white paper.
Sponsored by DLT Solutions
| Dynamic DNS—an Object Lesson in Problem Solving | May 21, 2013 |
| Using Salt Stack and Vagrant for Drupal Development | May 20, 2013 |
| Making Linux and Android Get Along (It's Not as Hard as It Sounds) | May 16, 2013 |
| Drupal Is a Framework: Why Everyone Needs to Understand This | May 15, 2013 |
| Home, My Backup Data Center | May 13, 2013 |
| Non-Linux FOSS: Seashore | May 10, 2013 |
- Dynamic DNS—an Object Lesson in Problem Solving
- Making Linux and Android Get Along (It's Not as Hard as It Sounds)
- Using Salt Stack and Vagrant for Drupal Development
- New Products
- Validate an E-Mail Address with PHP, the Right Way
- Drupal Is a Framework: Why Everyone Needs to Understand This
- A Topic for Discussion - Open Source Feature-Richness?
- The Secret Password Is...
- RSS Feeds
- New Products
- All the articles you talked
11 min 15 sec ago - All the articles you talked
14 min 22 sec ago - All the articles you talked
15 min 42 sec ago - myip
4 hours 40 min ago - Keeping track of IP address
6 hours 31 min ago - Roll your own dynamic dns
11 hours 44 min ago - Please correct the URL for Salt Stack's web site
14 hours 56 min ago - Android is Linux -- why no better inter-operation
17 hours 11 min ago - Connecting Android device to desktop Linux via USB
17 hours 40 min ago - Find new cell phone and tablet pc
18 hours 38 min ago
Free Webinar: Hadoop
How to Build an Optimal Hadoop Cluster to Store and Maintain Unlimited Amounts of Data Using Microservers
Realizing the promise of Apache® Hadoop® requires the effective deployment of compute, memory, storage and networking to achieve optimal results. With its flexibility and multitude of options, it is easy to over or under provision the server infrastructure, resulting in poor performance and high TCO. Join us for an in depth, technical discussion with industry experts from leading Hadoop and server companies who will provide insights into the key considerations for designing and deploying an optimal Hadoop cluster.
Some of key questions to be discussed are:
- What is the “typical” Hadoop cluster and what should be installed on the different machine types?
- Why should you consider the typical workload patterns when making your hardware decisions?
- Are all microservers created equal for Hadoop deployments?
- How do I plan for expansion if I require more compute, memory, storage or networking?




Comments
SELinux Simplified: Red Hat's Targeted Policy
The section "SELinux Simplified: Red Hat's Targeted Policy" is maddeningly unspecific. I wish that in this section an otherwise clear article had explained matters at a sufficient depth for a reader to understand precisely what the targeted policy does and does not allow.
Agreed
Agreed, rmlynch. I suppose defaulting to "use the SELinux policy GUI" was fitting for the title of the article, "SELinux Simplified". You could have enlightened many readers and saved a few pages in the magazine by just posting the link to RedHat Enterprise SELinux Guide.