Login startx with user permission not root

Related words for this problem is:

Login startx with user permission
Login startx with user login
Fix startx root login

This also known as "KernelTrap"

I now using BackTrack 4 Final installed a few weeks ago. This is my kernel version:

#uname -a
Linux bt 2.6.30.9 #1 SMP Tue Dec 1 21:51:08 EST 2009 i686 GNU/Linux

But i have a problem with startx to start. It only give permission to root to execute it. An easy way to explain is i need to "sudo -s"/"sudo -i" it first then i insert root password. After that i typed "startx" to start GUI(not in black and white session)

Until today, finally i found a solution to login startx with user permission. In my box,my user is "zer0"(this might different with your box). The problem to login startx with user is it not have right permission to run(This is normal for Linux have 2 layer security/permission).

The name of that file is ".ICEauthority" can be found in your home directory. You can see it by typing "ls -a".

#ls -a
. .gconf .macromedia
.. .gconfd .mcop
.0trace-kL7978 .gnome2 .mcoprc
.0trace-tp7961 .gnome2_private .moc
.adobe .gnupg .mozilla
.bash_history .gtk_qt_engine_rc .profile
.bash_logout .gtkrc-2.0-kde-kde4 .qt
.bashrc .gvfs .subversion
bt.sh home .sudo_as_admin_successful
.config hydra.restore .thumbnails
.dbus .ICEauthority .wireshark
.DCOPserver_bt__0 .kde .Xauthority
.DCOPserver_bt_:0 .kde3 .Xauthority-c
.directory lanmap.dot .Xauthority-l
.dmrc lanmap.png .xinitrc
dsniff.services .leo .xsession-errors
.elinks .liferea_1.4 yersinia.log
.esd_auth .local

NOTE: You will not see it without -a attribute because it is hidden file.

To see the permission of that file,you can type "ls -o".

#ls -o ~/.ICEauthority
-rw------- 1 root 183 2010-02-04 03:01 /home/zer0/.ICEauthority

OK, let do some simple magic to that file(.ICEauthority). First, open your Konsole then login with root. Just insert your root password if it ask you. The POC is like this:

#chown your_user /home/your_user/.ICEauthority

For me(in my box), i type like this:

#chown zer0 /home/zer0/.ICEauthority

To make sure you make it right or not, simply type ls -o again.

Then, i type "exit" to exit as root. Then it will see like this:
NOTE: this might be different on your box

zer0@bt:~$

After that i type startx
It will load into startx session and insert your password into all dialog boxes. Then you're done.