A Linux Conference as a Ritual

Sociological Images has an interesting post by Jay Livingston PhD about a tennis final as a ritual [1]. The main point is that you can get a much better view of the match on your TV at home with more comfort and less inconvenience, so what you get for the price of the ticket (and all the effort of getting there) is participating in the event as a spectator.

It seems to me that the same idea applies to community Linux conferences (such as LCA) and some Linux users group meetings. In terms of watching a lecture there are real benefits to downloading it after the conference so that you can pause it and study related web sites or repeat sections that you didn’t understand. Also wherever you might sit at home to watch a video of a conference lecture you will be a lot more comfortable than a university lecture hall. Some people don’t attend conferences and users’ group meetings because they would rather watch a video at home.

Benefits of Attending (Apart from a Ritual)

One of the benefits of attending a lecture is the ability to ask questions. But that seems to mostly apply to the high status people who ask most questions. I’ve previously written about speaking stacks and my observations about who asks questions vs the number that can reasonably be asked [2].

I expect that most delegates ask no questions for the entire conference. I created a SurveyMonkey survey to discover how many questions people ask [3]. I count LCA as a 3 day conference because I am only counting the days where there are presentations that have been directly approved by the papers committee, approving a mini-conf (and thus delegating the ability to approve speeches) is different.

Another benefit of attending is the so-called “hallway track” where people talk to random other people. But that seems to be of most benefit to people who have some combination of high status in the community and good social skills. In the past I’ve attended the “Professional Delegates Networking Session” which is an event for speakers and people who pay the “Professional” registration fee. Sometimes at such events there has seemed to be a great divide between speakers (who mostly knew each other before the conference) and “Professional Delegates” which diminishes the value of the event to anyone who couldn’t achieve similar benefits without it.

How to Optimise a Conference as a Ritual

To get involvement of people who have the ritualistic approach one could emphasise the issue of being part of the event. For example to get people to attend the morning keynote speeches (which are sometimes poorly attended due to partying the night before) one could emphasise that anyone who doesn’t attend the keynote isn’t really attending the conference.

Conference shirts seem to be strongly correlated with the ritual aspect of conferences, the more “corporate” conferences don’t seem to offer branded clothing to delegates. If an item of branded schwag was given out before each keynote then that would increase the attendance by everyone who follows the ritual aspect (as well as everyone who just likes free stuff).

Note that I’m not suggesting that organisers of LCA or other conferences go to the effort of giving everyone schwag before the morning keynote, that would be a lot of work. Just telling people that anyone who misses the keynote isn’t really attending the conference would probably do.

I’ve always wondered why conference organisers want people to attend the keynotes and award prizes to random delegates who attend them. Is a keynote lecture a ritual that is incomplete if the attendance isn’t good enough?

Maildrop, IMAP, and Postfixadmin

I have recently configured my mail server to use IMAP. I started doing this when I was attending Linux.conf.au so that I could read urgent mail using my EeePC while at the conference and then be able to deal with the more complex stuff using my laptop later on.

The next logical step is to have mail delivered to different folders in the IMAP account. While there are ways of doing this via the Subject and other header fields, my needs are not that great. All I need to do is to support user+extension@example.com going to a folder named extension in the user’s mail store. While changing my mail server I decided to install Postfixadmin at the same time.

My first attempt to use Maildrop was to put the following in the /etc/postfix/main.cf file:
mailbox_command = /usr/bin/maildrop -d mail -f “$SENDER” “$DOMAIN” “$USER” “$EXTENSION”

That seems to only work when you have local accounts, so I ended up setting fallback_transport = maildrop and then putting the following in /etc/postfix/master.cf:

maildrop unix – n n – – pipe flags=DRhu user=vmail argv=/usr/bin/maildrop -d vmail ${nexthop} ${user} ${extension}

Where vmail is a Unix account I created for storing mail. Then I added the following to /etc/postfix/main.cf. Some of these are probably redundant (such as the virtual_mailbox_base). The recipient limit is set to 1 because there are no command-line parameters for maildrop to support two recipients for the same message.
virtual_alias_maps = mysql:/etc/postfix/mysql_virtual_alias_maps.cf
virtual_mailbox_domains = mysql:/etc/postfix/mysql_virtual_domains_maps.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql_virtual_mailbox_maps.cf
virtual_gid_maps = static:2000
virtual_uid_maps = static:2000
virtual_mailbox_base = /mail
vmaildir_destination_recipient_limit = 1
virtual_transport = maildrop
maildrop_destination_recipient_limit = 1

The files /etc/postfix/mysql* all have fields user=, password=, hosts=, and dbname=. The queries in each of the files are as follows:
mysql_virtual_alias_maps.cf:query = SELECT goto FROM alias WHERE address='%s' AND active = 1
mysql_virtual_domains_maps.cf:query = SELECT domain FROM domain WHERE domain='%s'
mysql_virtual_mailbox_maps.cf:query = SELECT maildir FROM mailbox WHERE username='%s' AND active = 1

The /etc/courier/maildroprc file has the following contents:

# log the maildrop actions
logfile "/var/log/maildrop.log"
# parameters 1, 2, and 3 are the domain, user, and extension
# try making a backup (cc) copy of the mail but do not abort if it fails
exception {
  cc "$DEFAULT/.backup/"
# try delivering to the extension folder but do not abort if it fails
exception {
  if(length("$EXTENSION") != 0 && "$EXTENSION" ne "backup")
# deliver to the main inbox if there is no folder matching the extension or if no extension is specified
to "$DEFAULT/"

Installing Postfixadmin [1] was another challenge entirely. One of the complications of this is that there is no Debian package for Lenny (it seems that there will be one in Squeeze – Lenny+1).

I found David Goodwin’s tutorial on installing Postfixadmin and lots of other things on Debian/Etch [2] to be a very useful resource. I look forward to seeing a Lenny version of that document.

Please let me know if you can think of any way to improve this.

Employment Packages

Paul Wayper has said that he only wants to work for companies that will send him too LCA [1]. While that criteria is quite reasonable it seems overly specific. Among other things the varying location of LCA will result in the expense for the employer varying slightly year by year – which employers generally don’t like.

I believe that a better option is to have an employment package that specifies a certain amount of money (related to the gross income of the employee) should be set aside for training, hardware, or other expenses that help the employee (or their colleagues) do their job. Such an option would probably only be available to senior employees who are most able to determine the most effective way of spending the money.

For example an employee who earns $100,000 per annum might be permitted to assign 10% of their income ($10,000) to training or hardware that assists their job. Modern PCs are so cheap that any reasonable hardware requirements could fit within that budget with ease.

There are several benefits to such a scheme. On many occasions I have had colleagues who had inadequate hardware to do their work, slow PCs with small screens really impacted their productivity, in such situations buying a $400 PC and a $400 monitor for each person in the team could make a significant direct improvement to productivity before the impact on moralle kicked in!

Some years ago Lenovo ran some adverts for Thinkpads which said “demand one at the interview”. That made sense when a Thinkpad was an expensive piece of hardware. While there are still some expensive Thinkpads, there is a good range of cheap models, two which cost less than $1200AU and another eight which cost between $1200 and $1800. Now it makes more sense to allow each employee to choose their own hardware (both desktop and portable) and not even bother about issues such as whether the IT department blesses them. As Tom Limoncelli suggested in his LCA keynote, users are going to take more control over their environment whether the IT department like it or not, so it’s best to work with them rather than fighting them.

For training a common problem is that management can’t correctly determine which conferences are worthy of the expense of sending their technical staff. Then when a conference is selected they send everyone. It seems to me that when there are a number of conferences in a region (EG AUUG, LCA, OSDC, and SAGE-AU in Australia) there is a benefit in having someone from your team attend each one. Planning at the start of the year which conferences will be attended by each team member is something that appears to be beyond the ability of most managers as it requires knowing the technical interests and skill areas of most staff. If each employee was granted one week of paid time per year to attend conferences and they could determine their own budget allocation then they would be able to work it out themselves in a more effective manner.

Voting and Linux Australia

Dhanapalan writes about the small number of voters for Linux Australia elections [1]. I guess that blacklist-voting is partly to blame for my inactivity in this regard. Linux Australia is running pretty well so I don’t think there’s a great need for me to go out of my way to vote.

One thing that could be done given that LCA is an LA event is to give a voting session keynote status at LCA. Have it happen just after a keynote speech and have some prize given away to a random person who attends – the free laptops that were given away one year are not required, a free lunch voucher would be more than enough to increase the attendance.

A final factor that needs to be considered is the number of elections that we may vote in. I vote in Australian elections (state and federal), Debian votes (General Resolutions and DPL elections), and sometimes my local LUG. The amount of attention that I can focus on political issues is limited and divided with other elections that are more important.

Status of SE Linux in Debian LCA 2009

This morning I gave a talk at the Security mini-conf of LCA about the status of SE Linux in Debian. Here is a summary of the issues I covered:

General Status

In Lenny (the new release of Debian that will come out in a month or two) SE Linux is working well. Considerably better than in Debian/Etch. There is an installation document on my documents blog [1], it’s very easy, only two scripts need to be run with no parameters to do most of the work (5 commands in total). There is more detail on installing SE Linux in Lenny (and other issues) in the Debian Wiki [2].

The default configuration of SE Linux is “targeted”. Previously we had separate policy packages for “targeted” and “strict”, now they are configuration options for selinux-policy-default. It is also possible to have some users in the unconfined_t domain (like the “targeted” policy) and some in confined domains such as user_t. Changing to strict can be done one user at a time, this needs further documentation.


I maintain an APT repository of i386 and AMD64 packages for better SE Linux support. This includes libraries built to not need an executable stack (see my previous blog post for details [3]). It also includes i386 libraries that don’t need text relocations AKA execmod (see my blog post about why i386 must die for details [4]).

My Lenny repository includes policy packages before they appear in Testing as well as the packages that are modified to fix the execmod and executable stacks issues. I plan to maintain this repository for some time, at least as long as I am actively using Lenny, but the content will change.

I might back-port the newer upstream policy to Lenny at some later date. If I do this it will be near the time that Lenny+1 is released and I will put it in a different location to my current Lenny repository.

I am currently deciding what to do with packages from external repositories such as debian-multimedia (see my previous post for the background) [5]. I may have to create a separate repository for non-standard Debian packages which I then modify to better support SE Linux.

I also plan to build packages of Security Enhanced PostgreSQL [7] for Lenny and Lenny+1. After demonstrating it’s capabilities I will suggest that it be considered for Lenny+1.

Play Machine

I have been running a Play Machine (open root machine) [6] for most of the last seven years. In the near future (probably the week after LCA) I will upgrade it to Lenny. One thing that I didn’t mention is the fact that I plan to demonstrate other things such as SE-PostgreSQL in Play Machines.


I have a Xen server that is used for my Play Machine, I will run it as a SE Linux training machine and grant temporary ownership of a DomU to anyone who wants to learn and have a document with a list of tasks to complete to learn about SE Linux. I might be able to get it online this week. If so then I’ll make it available first to LCA delegates.

I will also set up a Bittorrent server for a Xen image for anyone who wants to go through the same SE Linux training program on their own machine – this will allow them a greater time limit and also avoid contention for my server. Unfortunately I have some problems with BitTorrent, I would appreciate any advice about running a torrent tracker.

Post Lenny

SE PostgreSQL is an exciting new development that I want to get in Debian. Initially I will create my own APT repository for it and include it in my Lenny repository. Hopefully it will become a standard feature in Lenny+1.

Security Enhanced X (the X window access controls) is a significant security feature. I hope to have that in Lenny+1, but it might not be possible.

Security Lessons from a Ferry

On Saturday I traveled from Victoria to Tasmania via the ferry (to attend LCA), they grossly failed in their security measures and provide three lessons for others:

  1. Make it possible for people to read security relevant documents .
  2. Make obeying the rules not be a cost and make the fact known.
  3. Don’t be lazy.

Here is the detail:

  1. When driving towards the ferry in a queue that lasted about 30 minutes just around the last corner there was a sign notifying me of the security rules. As soon as it was visible I started reading it but the security guard started frantically waving at me, the time taken to read it was holding up the queue. Therefore I never discovered the full list of things that I’m not supposed to do.
  2. One rule was that cylinders of gas (such as propane) were apparently banned and should be surrendered – presumably to prevent a gas leak in the confined space of the ship’s hold from risking an explosion. Anyone who did have such a gas cylinder would probably not want to have it stolen by the security people and would be inclined to lie and hope that the security people wouldn’t find it. If they had made it well known that such gas cylinders would be stored in safe keeping for the duration of the voyage and then returned then they would have been more successful.
  3. They wanted to check the luggage compartments of all vehicles. To check the tail-gate of the Kia Carnival van I was driving first required that all the bags which had been put over the back seat be removed (they were resting against the tail-gate and would fall out if it was opened). When the guard realised that they would have to wait for me to empty a lot of luggage out they decided to just trust me that I didn’t have any bad things on board (even though due to point #1 I didn’t know what bad things were). This problem happened a second time when I reached Tasmania and the guards wanted to search for fruit.

Security Enhanced PostgreSQL

Today was the first day of Linux Conf Au 2009 [1]. KaiGai Kohei was unable to attend the conference and give a database mini-conf presentation about his work on Security Enhanced PostgreSQL [2], so I gave the presentation in his place. It was a fairly difficult presentation and required that I learn a lot about PostgreSQL in a small amount of time. But the result seemed OK, the audience seemed reasonably interested and the questions indicated that there was no extreme negative reaction to it.

After the main presentation I gave a live demo using a Fedora 10 machine image that KaiGai provided. That ended about four minutes after the specified time, which was pretty good considering that I started about seven minutes late to allow the audience time to return from the lunch break.

Tomorrow I will give another talk for KaiGai on the topic of the Security Enhanced LAPP (Linux, Apache, PostgreSQL, and PHP) stack. I will also give a talk about the status of SE Linux in Debian/Lenny.

For both talks I have a separate laptop for the demos, so after tomorrow I will only take one laptop to LCA – which will probably be an EeePC (on some days at least).

Giving Away Hardware

For the last few years I have been actively seeking free hardware to give to members of my local LUG. Whenever a friend or business associate mentions that they are upgrading or replacing computers I enquire what they plan to do with the old ones and request that the old gear be given to me if there are no other plans for it. There is a moderate amount of hardware that I use for my own purposes, but the free hardware that is available is often in excess of my requirements and also sometimes just unsuitable for my use (I am happy to install a second-hand IBM or HP machine for a client but I won’t install a white-box machine).

One organisation that I sometimes give computers to is Computerbank [1]. The purpose of Computerbank is to take donations of old machines, fix them and install Linux, and then sell them for extremely low prices to people who can’t afford new machines. It’s been a while since I gave them any computers because for a long time the minimum specs on machines that they were willing to accept were higher than the machines that I obtained.

Generally I offer my old hardware to the mailing list of Linux Users of Victoria [2]. I offer not only working systems but also broken systems and other things that might be useless to most people – but are greatly desired by the small minority who can use them. One member of that list wants PC power supplies for repairing other electronic devices, so I collect batches of machines that are broken but appear to have working PSUs and give them to him. I once received a box of free two-button mice. I offered them to LUV members expecting that many people would want one or two for test machines. No-one wanted them for use as mice but one guy wanted all of them to use their sensors in robotics projects.

One thing that impresses me is the community spirit demonstrated. Often I will offer some free machines and the first response will be something like “I’d like to take that machine apart for the bits, but if someone wants a complete system please give it to them instead”. There aren’t many occasions when you see someone suggesting that they may not be the most deserving recipient for something that is free!

My aims in this effort are to help random Linux users in my area, and to help the environment by reducing the amount of land-fill. My efforts aren’t going to make a significant impact on the environmental situation, but they do make a significant impact on the availability of hardware for members of the Linux community – which seems to be of particular interest to people who want cheap machines for their children or grand-children.

I encourage other people to do similar things.

One thing that impressed me was the organisation of used hardware gifts at LCA. Near the start of the conference hardware was given away to anyone who put their hand up. At the end of the conference more hardware was given away (I expect it was mostly by delegates who lived locally). It would be good if this idea (which worked so well) was spread to other conferences.

Oracle Unbreakable Linux

Matt Bottrell writes about the Oracle Linux offerings presented at LCA 2008 [1]

The one thing that Oracle does which I really object to is the “unbreakable” part of their advertising. They have pictures of penguins in armour and the only reasonable assumption is that their system is more secure in some way. As far as I am aware they offer no security features other than those which are available in Red Hat Enterprise Linux, CentOS, and Fedora. The unbreakable claims were also made before Oracle even had their own Linux distribution, which gave them even less reason for the claims.

If someone is going to be given credit for making Linux unbreakable then the contributors list for the SE Linux project [2] is one possible starting point. Another possibility is that credit could be given to Red Hat for introducing so many security features to the mainstream Linux users before any other distribution.

In terms of improving the security of databases it’s probably best to give credit to Kaigai Kohei and the PostgreSQL team for Security Enhanced PostgreSQL [3]. I believe that NEC also deserves some credit for sponsoring Kaigai’s work, I am not sure whether NEC directly sponsored his recent work on SE-PostgreSQL but they certainly sponsored his past work (and are credited on the NSA web site for this).

Oracle’s Linux distribution is based on CentOS and/or Red Hat Enterprise Linux (RHEL). The situation with RHEL is that the source is freely available to everyone but binaries are only available to people who pay for support. CentOS is a free recompile of RHEL and a good choice of a distribution if you want a server with long-term support and don’t want to pay Red Hat (I run many servers on CentOS).

While Matt gets most things right in his post there is one statement that I believe to be wrong, he writes “One of the craziest statements I heard during the talk was that Oracle will only support their products running under a VM if it’s within Oracle VM“. My knowledge of Xen causes me to have great concerns about reliability. My conversations with MySQL people about how intensive database servers are and how they can reveal bugs in the OS and hardware are backed up by my own experience in benchmarking systems. Therefore I think it’s quite reasonable to decline to support software running under someone else’s Xen build in the same way as you might refuse to support software running under a different kernel version (for exactly the same reasons).

Matt however goes on to make some very reasonable requests of Oracle. The demand for native packages of Oracle is significant, I can’t imagine official Debian package support appearing in the near future, but RPM support for RHEL etc would make things easier for everyone (including Oracle).

A better installation process for Oracle would also be a good thing. My observation is that most Oracle installations are not used for intensive work and use database features that are a sub-set of what MySQL offers. I’ve seen a few Oracle installations which have no more than three tables! The installation and management of Oracle is a significant cost factor. For example I used to work for a company that employed a full-time Oracle DBA for a database with only a few tables and very small amounts of access (he spent most of his time watching videos of fights and car crashes that he downloaded from the net). Adding one extra salary for a database is a significant expense (although the huge Oracle license fees may make it seem insignificant).

The Failure of my Security Blogging Contest

On the 20th of January (8 days before the start of linux.conf.au) I advertised contest to write blog posts related to computer security for the conference Planet [1].

The aim of the contest was to encourage (by money prizes) people who had no prior experience in computer security to get involved by writing blog posts. The rules permitted security professionals to enter but only for an honourable mention, the money was reserved for people without prior experience.

The money that I initially advertised was a fraction of what was reserved for prizes, the idea being that if the contest went well then the prize pool could be easily increased but that if it didn’t go well then there would only be one small prize for someone to win by default. At the time I considered a single entry winning by default to be the worst case scenario.

The eventual result was that there was only one entry, this was from Martin Krafft on the point of keysigning [2]. Martin has prior experience in the computer security field which excludes him from a money prize, but he gets the only honourable mention. From a quick conversation with him it seems that his desire from entering the contest was to get his ideas about weaknesses in the keysigning process spread more widely, so this seems like a fairly ideal result for him. I agree with Martin that there are significant issues related to the keysigning process, but my ideas about them are a little different (I’ll blog about it later). His point about people merely checking that the picture matches on the ID and not verifying what the ID means is significant, the fact is that the vast majority of people are not capable of recognising ID from other countries. Other than requiring passports (which differ little between countries) I can’t think of a good solution to this problem.

Congratulations Martin! It is a good post and a worthy entry.

Now as to why the contest failed. I spoke to some people at the end of the conference about this. One delegate (who I know has the skills needed to produce a winning entry) said that I advertised it too soon before the conference and didn’t give delegates time to write entries. While I can’t dispute his own reasons for not entering I find it difficult to believe that more than a small proportion of delegates had that motivation. The LCA Planet had some lengthy posts by other delegates, and the guy who won second prize in the hack-fest spent something like 20 hours coding on his entry during the conference time (I suspect that my contest had the potential for a better ratio of work to prize money). Also the 8 days before the conference started was a good time to write entries for the contest.

One suggestion was that I propose that the conference organisers run such a contest next year. The problem with this is that it’s difficult to say “I tried this and failed, could you please try it too”. If nothing else I would need some significant reasons to believe that the contest has the potential to be more successful before attempting it on a larger scale. If the contest had been backed by the LCA organisers then it might have been more successful, but that possibility seems unlikely (and there is scope for an event to be more successful than mine while still being a failure). The reason that I consider it unlikely that official support would make it more successful is that I first advertised the event on my blog (syndicated to the conference Planet). Everyone who has a blog and attends the conference can be expected to have read about it. I then advertised it on the conference mailing list which I believe had as subscribers a large portion of the people who have enough spare time to create a blog specifically for the purpose of entering such a contest.

A blogging contest related to a conference but which had a wider scope (IE not limited to one field but instead covering anything related to the conference) might be successful. If someone wants to run such a contest next year then it’s probably worth doing.

Of course I have not given up on the plan of getting more people involved in computer security, expect to see some blog posts from me in the near future with other approaches to this. Suggestions would be appreciated.