No text in Flash with libflashplayer in Linux

13 04 2008

It seems that Macromedia/Adobe finally managed to produce a Flash plugin which doesn’t crash your browser on every second Youtube video you want to see. Although the FreeBSD patches that I have seen and some reports might even indicate that this was a Kernel problem. No idea, but – you might be suffering from the same problem as I did and have invisible fonts on some Flash pages that you visit. For me, this was the case after a reinstallation. Looking for clues on Google, I’ve seen mentions of this from as early as 2004, with some tips about fixing the configuration for the X Font server xfs, which must have been so broken that it isn’t in use any more. I’ve found a minimal example to see if you’re affected or not, too: If you don’t see the text next to the checkboxes on this political cartoon on CNN, then your problem will be that the Arial font is missing on your system. For other things like web sites, there are usually fallbacks to fonts which look about the same, but Flash is picky with this: If you don’t have the font installed, then you see nothing.

What you’ll have to do to fix this is to install the Microsoft Core Fonts package. If you are using Debian, run apt-get install msttcorefonts (or apt-get install msttcorfonts for earlier distributions) as root. If you are using Gentoo, run emerge corefonts as root. For other Linux systems, visit the Corefonts home page for instructions. Restart your browser after that. Now you should have the Arial font and be able to read the text in the Flash movies, too.

MathMap plugin and the Droste Effect

13 04 2008

Found a very cool tool today which allows you to produce self-referential images, like you know it from fractals. It’s called MathMap and can do tons of other things as well – it even gives you the ability to write new plugins in a simple way yourself. There’s a GIMP plugin and a standalone Mac OS X program of it. The filter that’s particularly interesting is called the “Droste effect”. Josh Sommers has a collection of images produced with it on flickr and a tutorial there as well.

Here are some of the pictures created with it:

Damn, what floor are we on?  Droste Cubed Step 2  Eternal Scream 2 (Alpha Blended)  Obligatory Droste Self Portrait

Moving a Linux installation to a bigger drive

7 02 2008

I recently wanted to move my Gentoo installation from one notebook HDD to another, a bigger one. Moving the data over the network was fairly easy: Boot up two laptops with live CDs, in my case I happened to have two Ubuntu 7.10 CDs flying around, then start up netcat as root on one of them and using it on the other to copy the data:
nc -l -p 3333 > /dev/hdX on the receiving part and dd if=/dev/hdX | nc -q1 <target IP> 3333 on the sending one. You can use any other port, 3333 was the example that I used, and remember to replace hdX with your actual device. Alternatively, and a lot easier, is to use a mobile HD case to connect one of the drives to an USB port and then do the same as above without using netcat. If you do it this way, with dd, then you will retain everything, including the MBR so even your boot manager will be preserved. The next thing is to resize (expand) your data partition so that it can grow to make use of the additional storage space on your drive.

At first I tried using Partition Magic and similar tools from Acronis, which were always helping me out during my Windows days. Granted, the software was already a little dated, but the ext3 partitions wouldn’t have been any trouble for them. But nada, Partition Magic refused to do anything as it reported that the disk geometry of the target drive didn’t match the physical disk geometry present, which could lead to data loss and corruption. I was afraid that this was a real problem that was induced through my transfer solution, but it actually reported the same on the original drive as well. I popped in the Ubuntu live CDs again and was delighted to see that the Partition Manager parted had no trouble to fulfill the task, and with the graphical version GParted which can be accessed through System > Administration > Partition Editor, you have a nice GUI which is reminiscent of Partition Magic itself. The Qt version QtParted strangely wasn’t able to do this task, so give the Gnome version a try if you run into trouble.
GParted in action

Making digital videos by means of a Bluescreen effect

1 11 2007

As you might know when you take a look at my very first posts to the blog, I have been interested in hacking around with Blizzard’s World of Warcraft game. Back when Blizzhackers was still up and the very first private servers popped up after a game server got hacked and people reverse engineered the server software, projects like WoWmapview (a program which could display ingame terrain) and the WoW Model viewer (a program which displayed models from the game, PC, NPC and monsters alike) popped up, too. The very first version of the WoW Model viewer was done by a smart chinese guy, but he released his sources (which I was the first to report on the Blizzhackers forum) and it seems that others have now taken up the project. Even more interesting: Some people are using this program to create their own videos by means of a Blue-/Greenscreen effect.

Very nice! WoW has definitely inspired lots of third party creations. Somebody even started to build a real time strategy game around it.

How to get meaningful backtraces

1 11 2007

The Gentoo people have a very good guide online which explains how to get meaningful backtraces in Gentoo and gives a general introduction to gdb, the GNU debugger, too. In case one of your applications continues to crash and you want to submit a helpful bug report, take a look at the guide to find out how you can contribute a backtrace with your report.

Educational videos on Reverse Engineering

30 10 2007

You have to debug a program. How can this be done? Two very good resources show you how to do it in video:

Lena’s “Reversing for Newbies” shows you how to use the free debugger OllyDbg. Just watching the very first video already teaches you much about using the debugger.

The Reverse Code Engineering Video Website uses the IDA debugger on the same example programs as above, showing how this graph based debugger can help to understand a program. There’s another video on IDA usage on the official website, too.

par2cmdline with Intel Thread Building Blocks

25 10 2007

Somebody took the sources for the par2 software, added multi-threading support for it with Intel’s Threading Building Blocks and promptly received an award for it. The minimal changes to the original code have been documented. Since the recovery blocks can be calculated independently from each other, parallelizing this process was obvious. Nice to see that somebody did this for a software which I love both for its application of mathematics and practical use.