/etc/shadow

Linux has a file for almost everything.

There is a place for users: /etc/passwd

A place for password hashes: /etc/shadow

A place for configuration: /etc/

A place for logs: /var/log/

A place for devices: /dev/

A place for processes: /proc/

Even the running system has a filesystem-shaped view of itself.

Linux has always had an interesting philosophy:
If you understand the system, you understand where things live.

But security makes the picture more complicated.

Knowing where something lives doesn't mean you can touch it.

You may know the file exists.

You may even know exactly what is inside it.

But chmod, ownership, capabilities, namespaces, SELinux, and the kernel itself may all answer the same question:
“Are you allowed?”

That is what makes Linux security fascinating.

The real boundary isn't the file.

It isn't the password.

It isn't even the command.

The boundary is privilege.

And once you start looking at Linux this way, the entire operating system begins to look like a map of permissions:

Who are you?
What can you see?
What can you execute?
What can you change?

And, perhaps most importantly...
What happens when you become root?

Welcome to /etc/shadow.

Where the interesting things are usually hidden just one permission away.

Ubuntu Tweak

Finally got rid of the stupid pink login screen using Ubuntu Tweak. What a pain!

Mandriva 2010

Although Mandriva 2010 was released a long time ago, I haven't had the time to upgrade until now.

Just like the last time, I received the message that "the system could not be safely upgraded to Mandriva Linux 2009" (yes, it did say 2009, probably someone overlooked that trivial bit). Nevertheless, as a professional penguin tamer, I decided to take the risk and continued. This time the estimated upgrade time was 5 hours. But in the end it only took about 1 hour and a half.

Brilliantly, the new system booted smoothly without any problems. Time to see what this great new system has to offer ;)

Ubuntu 10.04 LTS

Ubuntu 10.04 LTS was finally released last week, and I just managed to upgrade it today. Unlike Mandriva, to upgrade Ubuntu, I needed to use the alternate CD image instead of the normal one.
The upgrade took about an hour, which was actually quite long for such a newly installed system. However, on the bright side, it could be done while the system was running.

The Ubuntu guys boasted about the 10 second startup time. And in fact, my new system booted really fast. I doubt if it's as fast as 10 seconds though :P

There's a very annoying problem with the new Gnome button layout: the minimize, maximize, and close button are moved to the top left of the windows, whichever theme you use. A guide to fixing that problem is available here: http://www.howtogeek.com/howto/13535/move-window-buttons-back-to-the-right-in-ubuntu-10.04/

Ubuntu

So I got a new laptop, and of course I installed another Linux distro on it. Ubuntu seems to be a very popular one now, so I decided to give it a try.

Gnome seems to have improved a lot since the last time I tried it on Fedora. After some modding it looks quite awesome now ;)

Another thing I like about Ubuntu is the free 2GB Ubuntu One space I can use to synchronize and share my data.

Is cloud computing really the way to go?

Some updates

So I updated my kernel to 2.6.29.1, however the computer failed to boot. Probably there were some changes in the system structure. I guess I'll stick with 2.6.27 for a little more.

On the bright side, I have finally managed to find a way to connect to vpn from my Linux box. At first I went through the trouble of installing the Cisco VPN client for Linux, but no matter how hard I tried it couldn't connect to the gateway. Next I tried OpenVPN, but it didn't seem to be compatible either. In the end I tried vpnc. It was impossible to get it to work using certificate authentication, however group authentication worked fine ;)

Now probably there'll be no big changes until Mandriva Linux 2010 comes out!

2009.1

So Mandriva 2009 Spring Edition (2009.1) has been out for a few months, but I'm too lazy to update it. To be honest, I was quite satisfied with 2009, until recently when Yahoo changed their protocol and my old version Pidgin couldn't connect to their server anymore. A lame reason I know but that was the thing that helped me defeat my laziness and download the new image.

This time, instead of burning the image to dvd, I have decided to mount it locally and use it as an update media. Here's the command to add it to urpmi database:

$ urpmi.addmedia --distrib cdrom /mnt/2009.1/i586/
adding medium ""Mandriva Linux - 2009 Spring (Free) - main" (cdrom1)" before remote medium "Mandriva Linux - 2009.0 (Free) - Installer"
adding medium ""Mandriva Linux - 2009 Spring (Free) - contrib" (cdrom2)" beforeremote medium "Mandriva Linux - 2009.0 (Free) - Installer"

Then the pidgin update:

$ urpmi pidgin
To satisfy dependencies, the following packages are going to be installed:
 Package                        Version      Release       Arch
(medium ""Mandriva Linux - 2009 Spring (Free) - main" (cdrom1)")
libpurple0                     2.5.5        5mdv2009.1    i586
pidgin                         2.5.5        5mdv2009.1    i586
pidgin-i18n                    2.5.5        5mdv2009.1    i586
pidgin-plugins                 2.5.5        5mdv2009.1    i586
1.2MB of additional disk space will be used.
4.9MB of packages will be retrieved.
Proceed with the installation of the 4 packages? (Y/n) y

installing pidgin-i18n-2.5.5-5mdv2009.1.i586.rpm pidgin-plugins-2.5.5-5mdv2009.1.i586.rpm libpurple0-2.5.5-5mdv2009.1.i586.rpm pidgin-2.5.5-5mdv2009.1.i586.rpmfrom /mnt/2009.1/i586/media/main
Preparing...                     #############################################
    1/4: libpurple0            #############################################
    2/4: pidgin-plugins        #############################################
    3/4: pidgin-i18n           #############################################
    4/4: pidgin                #############################################

Unfortunately, the problem with pidgin was only fixed in version 2.5.7. So in the end I had to grab the latest version 2.5.8 off the Internet to get it done.

Maybe tomorrow I'll try updating the kernel next.