Changed File Permissions On /Bin - Now Kubuntu Is Frozen [RESOLVED]

[mechanism]

I was trying to set file permissions and directory permissions and managed to lock myself out of Kubuntu. Actually, Kubuntu will not even boot up other than in safe mode. I'm pretty sure it all happened when I changed the permissions on the /bin and /usr directories from what ever they were to "700".

The affect was immediate. The computer just locked up. I have rebooted the machine into safe mode and tried running the command "sudo chmod bin 755" but was returned this error:

root@closet:/# sudo chmod bin 755
sudo: can't open /etc/sudoers: permission denied
rot@closet;/# Exim configuration error in line 622 of /var/lib/exim4/config.autogenerated:
user mail was not found

How do I undo what I did?

Thanks and errrrr....lesson learned.

[Snowhog]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

Don't use sudo with the command. In Recovery Mode (Single User) you are already running as root. That's what the # at the end of the prompt denotes.

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

This is what I get without "sudo"

root@closet:/# chmod bin 755
chmod: invalid mode: 'bin"
try chmod --help for more information

Thanks!

[kubicle]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

It's:

chmod 755 bin

not:

chmod bin 755

'bin' is not a valid format for permissions mode -> error

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

Well, that's what happens when you try to type before coffee. Okay, I'll give this a try when I get home tonight.

Thanks!

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

I executed the commands using the above syntax and they executed without error. However, I'm still locked out. If I wait long enough I finally get to the Kubuntu login screen. I put in my credentials then got a pop up error box saying:

bash: /etc/bash.bashrc: Permission denied
I have no name!@closet:~$

I can not recall which folders I initially changed so there may be another folder or file whose permission in screwed up. >
Two questions:

(1) I used chmod 755 bin on /bin and /usr and /etc. I then went back again and used "chmod -R 755 bin" and also the same on /usr. This took a few minutes to complete but did complete without errors. Did I do this correctly?

(2) What should the /bin, /usr, /etc, /<any_other_folder_that_may_be_causing_problems> permissions be set to? Is 755 correct?

Thanks!

[kubicle]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

Changing permissions (or ownerships) recursively (with -R option) on system directories is dangerous and can lead to severe headaches, as although most of the directories should be 755, subdirectories and files often are something else entirely (some executables need to be set SUID, for example, and some directories and files have limited permissions for security reasons).

You may have mangled the system beyond 'easy' repair, but of course you *may* get the system up by repairing file permissions manually (but reinstalling is probably the way of least resistance).

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen


Ouch! I was afraid of that. I'll try changing all the directories to 755 and see if that helps. I may have already mangled everything. As a last ditch effort, I'll change everything to 766 and see what that does.

You know, Kubuntu should not let critical permissions be changed without some type of warning! I had no idea that I was about to screw up my system. I know, I know...I was under "sudo" but even then, I should have gotten a warning stating that harm could be done. Somethng. Anything.

Someone could easily write malicious code to change folder permissions which would disable a computer. Ok....I'll try a few more things before a fresh install.

I'll post back the results.

Mike

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

Okay, I'm making a little progress here. I booted into safe mode and typed

cd /

to get to the top level of the directory. Then typing

ls -l

showed the bin, usr, etc, home, and other directories. I then changed the permissions to 755 for every directory located under "/".

I rebooted and got all the way to the login screen and typed in my credentials. This time I did not get an error. Actually, I did not get anything at all. I typed in my username and password, the screen went blank for about a second then returned to the login page. I typed in my credentials again and the same thing happened. No errors. It seems like Kubuntu can't find what it is looking for.

So, what file is Kubuntu hunting for when I login and what should the permissions be set to on that file?

Thanks!

Mike

[dibl]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

I typed in my username and password, the screen went blank for about a second then returned to the login page. I typed in my credentials again and the same thing happened.

This "login loop" phenomenon has been found to be caused by several different conditions:

1. Full filesystem

2. Root permissions on some part(s) of the /home settings files/folders

3. Broken video driver (has to be re-installed)

4. Recently, a bug in language-pack-kde-en.

I'll speculate that your most likely problem is #2. If, in text mode, you can change directory to your /home directory, and delete the hidden ".kde" folder, that is often the culprit, and then restart the system and try a normal login. So that would be:

cd /home
rm -rf .kde
sudo shutdown now -r

Doing this will cost you your existing desktop settings -- a new .kde folder will be created at your next successful login and you'll have to configure the desktop and KDE behavior again. Good luck with it.

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

Thank you. I'll give that a try tonight when I get home.

Mike

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

Well, that did not work. I still have that cycling login screen. I sign in, screen goes blank for about one second, then back to the login screen. I have three users setup at login and no matter which one I pick, the same thing happens.

Can you think of anything else I should try before I go for the reinstall?

Mike

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

Just in case of a situation just like the one I am in, I did make an image of my sda2 partition just last week so I have the full install already backed up. I used Partimage to make a file. Because my storage device is FAT32 the max file size is 4.0 Gigs so the Partimage backup is actually several different files listed as below

[quote]sda2.pmg.gz.000
sda2.pmg.gz.001
sda2.pmg.gz.002
etc.../quote]

Do I just select the ".000" file first? Will Partimage understand that the total file is broken up and retrieve each file in order?

Thanks!

Mike

[maestrobwh1]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

I did this for kde4 and actually deleted .kde4 from home (logged into kde3) and I still got the issue. I assume that I should not delete .kde if I am only having the issue with kde4. I did a sudo chmod 777 -R command on the .kde4 folder as well. Perhaps an update will fix it soon.

I typed in my username and password, the screen went blank for about a second then returned to the login page. I typed in my credentials again and the same thing happened.

This "login loop" phenomenon has been found to be caused by several different conditions:

1. Full filesystem

2. Root permissions on some part(s) of the /home settings files/folders

3. Broken video driver (has to be re-installed)

4. Recently, a bug in language-pack-kde-en.

I'll speculate that your most likely problem is #2. If, in text mode, you can change directory to your /home directory, and delete the hidden ".kde" folder, that is often the culprit, and then restart the system and try a normal login. So that would be:

cd /home
rm -rf .kde
sudo shutdown now -r

Doing this will cost you your existing desktop settings -- a new .kde folder will be created at your next successful login and you'll have to configure the desktop and KDE behavior again. Good luck with it.

[mechanism]

Re: Changed File Permissions On /Bin - Now Kubuntu Is Frozen

Just to update the thread - I never did recover from the permission issue. Thankfully, I had made a backup image of my Linux partition which I restored in just a couple of hours and was back online. Thank the Lord for Partimage!

Take my advice, If you've not made a backup image yet then do so now. Do it now! Now! Why are you still reading this? What are you waiting on? Now! Get moving! Now, now, now!

Thanks!

Mike