Gl.ib.ly

As mentioned in other articles I sometimes like to output data in CSV format and redirect to a file and then open that file with my favourite spread sheet application to create pretty charts instead of using awk to create command line graphs or gnuplot. However I recently found out that Microsoft Excel doesn't do Gantt charts by default, so what follows is an explanation of what I was trying to do and how I simulated a Gantt chart in Excel.

Continue reading "Gantt charts in Microsoft Excel"

Sometimes Moodle introduces some nice new configuration variables and I like to make sure that I know what they are and where they are. So to begin my investigation without heading off to the web I use the following command to get me a sorted list of the $CFG variables.

Continue reading "All configuration variables in Moodle code?"

Today I am adding a malicious system call to the Linux kernel which will allow the caller to do something they cannot normally do in user mode. When attacking a Linux box our goal is usually to become root; as root we can do anything we like, so the system call I will add to the Linux kernel gives the caller real and effective user ids of zero.

There are relatively few tutorials out there on how to do this, unfortunately there a little differences between versions of Linux that can easily stump beginners, so this tutorial tries to give you an environment which you can easily replicate using a virtual machine and go through the tutorial.

Continue reading "Adding a malicious system call to the Linux kernel"

Once upon a time I was comparing some Java files. Now one way to find plagiarism among students who share program code is to look at the white space traces in a file. Students typically try and edit the source code: changing variable names and function names; however, they usually fail to conceal the original author's white space patterns. White space consists of characters which don't appear on screen such as spaces, tabs, and new line characters. Anyway you can catch lots of cheaters by looking at the white space patterns in files ... maybe that's another blog entry, so back to this one.

Continue reading "Creating an HTML file with white space traces"

I generally hate to update things which work just fine. There is usually very little reason to: the application is in use because the stability and feature set of the current version are good. Now I have used Skype for years (probably only using 20% of the available feature set) and I always loathed upgrading because it'll try and install a bunch of stuff I don't need. Which is bad, but installing utter crap now that's just not on. Take a look at what Skype's FireFox addon does to my links below.

Continue reading "Skype: And the crappy browser addon"

Today I got the urge to see how many logins we had on some of our Apache servers in November. We host more than one moodle site on one server and so I wanted the total number of logins we handled. As usual this ended up becoming an awkward but useful one liner.

Continue reading "Getting logins per day in Moodle"

Hello and welcome to my blog. I'll post on about pretty much everything, but mainly you can expect a raft of posts about Moodle, MySQL. Postgres, Debian, SLES 10 (probably rants), high performance stuff and a peppering of security related goodness. If you've just stumbled across this blog come back soon and I might have something worthwhile for you to read.