I am one of Jim Gettys’ Jedi mind trick victims, with a record breaking answer of ten seconds when asked how long I thought it takes for Linux to wake up from suspend-to-ram. Out by a mere four orders of magnitude. It’s always good to remember: never assume anything, and don’t be a guesser.

I usually write up some notes on all the SELinux changes in a new kernel release, but I’ve been a little busy with RHEL5 coming up, and the notes for 2.6.18 will have to wait a while. I’m happy, though, to see that secmark (reworked SELinux network controls, integrated with iptables) went in.

The FOSS.IN/2006 CFP is open for another week. I’ve submitted a couple of talks and hope to attend one way or another. Due to a change of venue, I don’t think there’ll be cows walking around the conference this year, but you can’t have everything. It’s a truly amazing event, and I’d say it ties with LCA as favorite Linux conference.

Jeff Waugh linked to an interesting presentation blog, which features an inspired Darth Vader vs. Yoda example, which is itself a great example of presentation “zen”.

There’s a week left, too, on the SELinux Symposium 2007 CFP. A lot of great work has been done on usability and developer tools during the year, and the symposium will be an useful opportunity to see how the project has advanced overall and where its heading.

Erich Schubert has been keeping the SELinux effort in Debian moving forward; and SELinux itself, with Debian leading the deployment of auto-configuring modular policy. (Note: see comments for more details on this). As one of my sparc boxes is running Debian, I hope to get it updated to a development version and have a closer look at what’s happening there. If you’re interested in SELinux on Debian, see the project page.

The BSD securelevels LSM has finally been terminated.

In an ideal world, I’d love to see more of the Linux security development community rally around SELinux, rather than be split across various projects. Aside from believing that SELinux is the right model on a fundamental level, with its policy-flexibility and complete coverage of security-relevant interactions in the kernel, it takes a lot of work to make the transition from DAC to MAC in a general purpose operating system. It’s such a hard problem that it’s never succeeded before, and I guess I see SELinux as the big opportunity to nail it; with the availability of the OS source code, a global developer team and a solid architecture based on decades of research by the NSA — all of the building blocks are there.

Competing ideas are of course essential, but it’s one thing to convert a research idea into an LSM and publish some papers; and quite another to build developer, user and academic communities, to continually evolve the software on every level, and to support many tens of millions of users across several widely deployed OSs, in environments ranging from consumer telephones, to Internet servers, through to operational systems protecting national security and all manner of amazing things that I wouldn’t be able to talk about, even if I knew about them.

So, it’s not that I think BSD securelevels or some other security project is a bad thing (although, honestly, some are not so wonderful), it’s a matter of what’s practical and suitable for inclusion in the mainline Linux kernel. To make an analogy from the networking world: it’s good that things like STREAMS exist, and that people have done real work on things like TCP offload engines, but it doesn’t mean that they belong in the mainline Linux kernel.

Slides from all of the talks at Netconf 2006, and photos, are being made available at
http://vger.kernel.org/netconf2006.html (bottom of the page).

It’s been a great summit again, and it’s very sad to be leaving Tokyo. Thanks to all of the sponsors, and especially Yoshifuji-san of USAGI.

DaveM made a new friend at the University of Tokyo:

Update:
Uploaded a photo set from the conf: click here.

Here are the slides from my Netconf 2006 talks.

• Better IPsec SA Resolution (PDF)
  Some discussion of the case where we need to send a packet, but have no IPsec security association for it. Generally, we currently return EAGAIN to applications and initiate an SA negotiation, but this seems less than optimal. One approach is to not return an error (which some implementations do) so that applications don’t die from surprise. We could also queue the packet and wait for the negotiation to complete, with appropriate semantics for various scenarios.

  The big question at this point is: in what situations are people seeing this? Generally, the key manager will maintain SAs as needed, and the case of not having one established is believed to be unusual, but we don’t really know for sure. Opportunistic encryption would likely benefit from proper queuing, but it’s not clear how widely it’s deployed.

• OLPC Networking Overview (PDF)
  Brain dump of what I understand currently of the networking aspects of the OLPC project, which I thought might be of interest to other kernel network developers.
• Mandatory Access Control Networking Update (PDF)
  Coverage of developments in MAC networking over the last year, including the new Secmark controls & SELinux, completion of the native xfrm IPsec labeling to meet LSPP/EAL4 , and CIPSO support. Paul Moore from HP will be giving a more detailed talk on CIPSO today or tomorrow.

Also, met up with some local SELinux developers at lunch time: Kaigai Kohei , Kazuki Omo and Yuichi Nakamura. After noticing a six-page SELinux article in a Japanese Linux magazine last night while shopping in Akihabara Electric Town, I asked them if they’d seen it and it turns out that Nakamura-san wrote it, and that he writes a monthly SELinux column for the magazine. We had some discussion about SELinux usability, SE postgresql and JFFS2 support. Unfortunately, we ran out of time — hopefully we’ll get to talk again at the next SELinux symposium.

(Which reminds me to note that the CFP submissions are due on October 9th).

I wonder how many people know that there’s an official Netfilter Song.

I’m in Tokyo for Netconf 2006.

Harald Welte told me at breakfast that Motorola A1200 phones run SELinux, and that a million of these have been sold in China. It’d be interesting to see their security policy.

Update:
The A1200 is not running real SELinux, it’s a derived LSM called “Motorola Access Control”. The source is available here:
https://opensource.motorola.com/sf/frs/do/listReleases/projects.a1200/frs.sample_package

Wade Mealing blogged Do the Fedora Developers run with SELinux enabled ?, after encountering a lot of AVC messages on his Fedora Core box. Looking at the messages, it seems that the system is out of whack generally and needs to be relabeled. The cleanest way to do this is:

# yum update
# touch /.autorelabel
# reboot

and the early init scripts should fix the labels.

The hint that it’s a general labeling problem is the presence of file_t and unlabeled_t labels in the AVCs, which are generic fallback values and should not typically be seen in the wild. In fact, any AVC messages or SELinux issues for a normal user should be regarded as a bug.

This type of thing should not normally ever happen and we’d really like to know how the system got into this state. It could be that the policy has not been kept up to date with the rest of the system, which should only really be an issue for people who are playing with development versions of the distro and selectively upgrading rpms. It’s also possible that the presence of hard disk error messages in the logs has something to do with it. Another possible cause is mounting a non-labeled disk somewhere critical in the fs. Without more detailed information, we don’t know for sure, so please always report bugs.

Any of the following mailing lists are good for this:

• http://www.redhat.com/mailman/listinfo/fedora-list
• http://www.redhat.com/mailman/listinfo/fedora-selinux-list (subscriber-only)
• http://www.nsa.gov/selinux/info/list.cfm

SELinux-related bugzilla entries are typically resolved very quickly:

• https://bugzilla.redhat.com/bugzilla/index.cgi

Bugs are good.

Send us some!

Note that soon, setroubleshoot will have a plugin for this specific issue, and explain to the user what’s wrong and what to do about it.

A great security book, Security Engineering is now available online for free. The author, Ross Anderson, convinced Wiley to make it available so that as many people as possible can have access.

Bruce Schneier is quoted `If you’re even thinking of doing any security engineering, you need to read this book’. I’d go further and extend this to any kind of engineering. I think it’s one of those rare books that pretty much everyone involved in computers or technology in general should read (another might be Brooks’ The Mythical Man Month). Security Engineering is packed with knowledge and deep insight across a wide range of topics. It’s also comprehensively referenced, making it a great stepping off point for further study.

For those interested in learning more about historical Mandatory Access Control, MLS and other advanced security models, the Multilevel Security chapter is worth reading. While only touching on Type Enforcement, it provides a lot of background material for understanding the historical context of SELinux.

Also, Ross has a blog.

I was kind of surprised and also happy to see that Dan Kegel’s The C10K Problem is still being actively maintained after seven years (with recent updates covering Evgeniy’s kevent work). That’d have to make it one of the oldest active Linux documents on the Internet. Which is like how people describe volcanoes.

I’ve glanced through a copy of the new SELinux book, SELinux by Example, and it looks to be very comprehensive. I’d say it’s the best current resource on the subject.

FC6 will include some SELinux usability improvements, most notably, a new GUI desktop tool setroubleshoot, which was inspired by the idea of the Gnome Bug Buddy. The idea is to notify the user when something goes wrong (e.g. an AVC denial), and present them with a clear explanation and an easy means to do something constructive in response. In addition to the detailed design documentation at the above link, setroubleshoot has been blogged about by Karl MacMillan and Dan Walsh.

Setroubleshoot Alert.

There’s also a new facility for maintaining the correct labels on files, restorecond, which runs in the background and relabels files automatically in certain cases (e.g. for files being served by Apache). This is of course a trade-off between security and usability, and is entirely configurable via

/etc/selinux/restorecond.conf

It’s really great to see these kinds of improvements being made. Security is a hard problem, and such problems take a lot of time and effort to solve effectively. We’re getting there.

I’ve created a new account, for non-work related stuff. Feel free to add me.

I received an OLPC test board on Friday and spent much of the weekend playing with it.

The test board seems to work as expected, with a couple of minor BIOS bugs. I haven’t had much luck with the OPLC Fedora build images, which I gather contain the neat UI stuff, although normal Fedora development snapshots seem to be ok. I’ve only done text mode so far (not sure if I’ll even bother trying to get Gnome running with 128K of RAM).

Some possibly helpful tips:

• I’m using a portable Segate 60GB USB hard drive, which has a second USB cable just for power. This is useful as the OLPC board doesn’t have enough power for the drive via any of its onboard USB ports, and you need the boot drive connected directly due to a BIOS bug. So, I can connect the power-only USB cable to a powered hub and the data cable to the board.
• For wired ethernet, I’m using an old SMC 2208 USB ethernet adapter, which uses the rtl8150 driver (it’s the very last item in the driver selection dialog during the Fedora install).
• I also have a new D-Link DUB-E100 USB ethernet adapter, which according to online docs, should work with the usbnet driver, although I haven’t had any luck with that.

It looks like there are many interesting and novel engineering problems to be solved for this project — certainly no shortage of solid challenges for software and hardware hackers. All kinds of useful development info is being added to the OLPC Trac system.

The Call for Papers for the 2007 SELinux Symposium has been announced. Submissions close on October 9th.

The symposium will be held in Baltimore again, from March 12-16, 2007.