I’ve uploaded the slides from essentially all of the talks I’ve given to Slideshare. This is likely more useful than my previous strategy of dumping them in a directory and leaving the rest up to search engine bots.

Click here for the full list of slides. They are all published under the Creative Commons attribution share-alike license.

One interesting slide title, which I’d forgotten about, is Kernel Security for 2.8, from the 2004 Kernel Summit. This was from when we were still expecting a 2.7 development kernel leading to a 2.8 stable kernel — I think Linus announced the change in development model at that summit.

Included in this set of slides are several introductory and deeper technical overviews of SELinux; I hope they are useful for people who are looking for information for themselves, or if making their own slides. As the license suggests, please feel free to copy and extend them (but note that the older ones are going to be more out of date).

I mean, SLUGs…

Paul Wayper gave a couple of talks on SELinux at this weeks’ SLUG meeting, and includes links to a couple of very useful slide decks:

• SELinux for Everyday Users
• SELinux for SysAdmins

The sysadmin slides look particularly useful, as they focus on solving common issues such as running FTP/SAMBA/Apache servers, and provide some very useful general tips, such as looking in the audit log and using policy booleans for high-level policy tweaking.

These slides may be the best, short introduction for sysadmins on the topic that I’ve seen. It’s a difficult thing to get right.

Here’s an update on the major changes to the kernel security subsystem for the 2.6.30 kernel.

• TOMOYO
  The TOMOYO security framework from NTT was merged. This is the first significant LSM scheme to be merged since SELinux in 2003. TOMOYO is characterized by its targeting of non-technical users, where security policy is automatically generated with a “learning mode” tool. This scheme utilizes pathnames for determining access to filesystem objects. Another interesting feature is that a domain, i.e. an active subject which acts on objects, is defined as a history of process invocations, rather than a single process. This allows policy to be applied to a particular branch of processes in the system. For example, an access permitted for init->httpd->perl may not be permitted for init->httpd->bash. Sample policy may be found here.
• IMA
  IBM’s Integrity Measurement Architecture was also merged. This uses the TPM to verify and store cryptographic checksums of files used by the system, i.e. measurement. If a measured file has been modified on disk, this will be detected and stored permanently in the TPM. The aim is to help detect attacks based on modifying files—such as executable binaries or configuration files—although it cannot detect runtime attacks, and requires checksums to be known in advance for the full system startup chain. Files to be measured may be specified in a policy loadable via securityfs.
• Remove Old SELinux Network Controls
  The original SELinux network controls were deprecated by the iptables-based Secmark system several years ago, although they remained available via the compat_net option for the likely few people who were using them. The old code has now been removed entirely, and users should transition to Secmark: Paul Moore has written a detailed guide for this.

The remaining changes were primarily bugfixes and enhancements across most parts of the security subsystem, including SELinux, SMACK, and keys.

Paul and I are finalizing the schedule for the security microconf at the upcoming Linux Plumbers Conference. It’s looking like a great line-up at this stage—stay tuned for more details soon.

Just a reminder for SELinux developers and anyone interested in the internals of SELinux that the SELinux Developer Summit CfP closes on July 1st, which is about a week away.

Details of the CfP are here. Don’t forget to join the event mailing list if you’re attending.

Proposals for presentations, lightning talks, and development sessions should be submitted via email per the instructions in the CfP. Proposals do not need to be especially detailed: if you have a good idea, simply send it in.

For reading this, you are rewarded with a mystery object (pictured above). See if you can figure out what it is before clicking on it and reading the comments @ flickr.

In the process of preparing my talk for KCA, I re-read the classic paper: The UNIX Time-Sharing System by Ritchie & Thompson. This paper was revised several times between 1973 and 1978, and the authors’ observations are well worth remembering:

Second: there have always been fairly severe size constraints on the system and its software. Given the partially antagonistic desires for reasonable efficiency and expressive power, the size constraint has encouraged not only economy, but also a certain elegance of design. This may be a thinly disguised version of the “salvation through suffering” philosophy, but in our case it worked.

Third: nearly from the start, the system was able to, and did, maintain itself. This fact is more important than it might seem. If designers of a system are forced to use that system, they quickly become aware of its functional and superficial deficiencies and are strongly motivated to correct them before it is too late. Because all source programs were always available and easily modified on-line, we were willing to revise and rewrite the system and its software when new ideas were invented, discovered, or suggested by others.

It’s clear that the success of Linux (and FOSS more generally), is underpinned by these principles.  These principles are not merely about technology; they’re a way of thinking about technology and the people who create and use it.