Aventures in stupidity with chmod and chattr [SOLVED]

underpenguin · 2008-01-16 19:45:22

Well, I somehow managed chmod my /etc/resolv.conf so that not even when su-ing root can I delete / chmod / chown it. Any ideas?

Last edited by underpenguin (2008-01-17 19:19:02)

Cerebral · 2008-01-16 19:47:40

who owns it? ls -l /etc/resolv.conf

underpenguin · 2008-01-16 20:00:53

4 -rw-r--r-- 1 root root 68 2008-01-04 21:23 /etc/resolv.conf

Last edited by underpenguin (2008-01-16 20:01:42)

Cerebral · 2008-01-16 20:06:08

Those perms are fine - what about /etc? ls -ld /etc

Are you using ACLs?

underpenguin · 2008-01-16 20:14:00

drwxr-xr-x 61 root root 4096 2008-01-16 13:42 /etc

(my problem is that my internet is super slow, issues with dorm 'net, so it takes me like 5 min to refresh/google etc)

acl is a filesystem? I'm not that I know of.

Cerebral · 2008-01-16 21:19:11

ACLs are access control lists - it's another way to specify permissions. You're probably not using them if you don't know what they are.

What's the exact output trying to chmod /etc/resolv.conf as root?

underpenguin · 2008-01-16 23:31:34

$ su
Password:
# chmod 777 resolv.conf
chmod: changing permissions of `resolv.conf': Operation not permitted

_adam_ · 2008-01-17 02:25:42

can you edit the file?
the perms are fine, why do you want to change them? but the fact that you cant change them as root is quite strange.

underpenguin · 2008-01-17 15:04:11

I know, its really wierd, I have no idea how I did it. I can open/read the file but I can't write to it. And a touch'ed a test file in /etc/ just to make sure it would work, and it did.

Cerebral · 2008-01-17 15:14:00

can you chmod the touch'ed file? What're the perms on chmod?

underpenguin · 2008-01-17 15:37:09

[ben@hoth ~]$ ls -la `which chmod`
-rwxr-xr-x 1 root root 39376 2007-11-15 10:13 /bin/chmod
[ben@hoth ~]$ touch /etc/test
touch: cannot touch `/etc/test': Permission denied
[ben@hoth ~]$ sudo touch /etc/test
[ben@hoth ~]$ sudo chmod 777 /etc/test

[ben@hoth ~]$ ls -la /etc/test
-rwxrwxrwx 1 root root 0 2008-01-17 09:35 /etc/test

[ben@hoth ~]$ ls -la /etc/resolv.conf
-rw-r--r-- 1 root root 68 2008-01-04 21:23 /etc/resolv.conf

Cerebral · 2008-01-17 15:46:10

... well I'm totally baffled.

underpenguin · 2008-01-17 15:49:06

Ha, well, thank you for your help. Maybe another l33t hax0r will come by and help

mr.MikyMaus · 2008-01-17 18:24:36

Just a quickshot: make sure the file /etc/resolv.conf is not opened by any program/process. You can use the lsof utility (pacman -S lsof) to see all opened files. Just run lsof | grep /etc/resolv.conf to see whether the file is opened by some program or not..

-m.

phrakture · 2008-01-17 18:55:01

Woah. What filesystem do you have? I can think of two possible things here.

a) Your FS is mounted read only
b) You set file attributes to block you from deleting it (such as ext2/3's immutable bit)

codemac · 2008-01-17 19:01:34

Can you try the following commands as root??

lsattr /etc/resolv.conf # will show you what special attributes are set.

If you see an i or an a surrounded by hyphens, run the respective command:

chattr -i /etc/resolv.conf
chattr -a /etc/resolv.conf

Thank you, and please come again.

underpenguin · 2008-01-17 19:18:18

Wow. Phrakture was right (and thanks for saving me the googlin' to find out how to fix it codemac). I probably did that while trying to get various programs from editing it (wanted to use static dns). Thank you very much everyone.

Cerebral · 2008-01-17 19:31:02

Huh - cool. I wasn't even aware of chattr. I fail.

dmartins · 2008-01-17 21:41:39

Well, I guess you do learn something new every day. And by you I mean me and Cerebral.

phrakture · 2008-01-17 21:50:16

underpenguin wrote:

Wow. Phrakture was right

Pff, this surprises you?!

Hah, kidding!

Misfit138 · 2008-01-18 02:03:01

phrakture wrote:

underpenguin wrote:
Wow. Phrakture was right
Pff, this surprises you?!
Hah, kidding!

LMAO!

Allan · 2008-01-18 03:38:22

Cerebral wrote:

Huh - cool. I wasn't even aware of chattr. I fail.

I didn't know about this either. And thanks to this thread, I can now fix what I am about to break playing around with it!

phrakture · 2008-01-18 06:56:53

Allan wrote:

Cerebral wrote:
Huh - cool. I wasn't even aware of chattr. I fail.
I didn't know about this either. And thanks to this thread, I can now fix what I am about to break playing around with it!

There's a long standing pacman bug regarding "immutable files". It's a chattr thing. I can't recall all the details, but basically the only way to change an immutable file (even as root) is to get rid of the immutable bit first. It's scary

Arch Linux

#1 2008-01-16 19:45:22

Aventures in stupidity with chmod and chattr [SOLVED]

#2 2008-01-16 19:47:40

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#3 2008-01-16 20:00:53

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#4 2008-01-16 20:06:08

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#5 2008-01-16 20:14:00

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#6 2008-01-16 21:19:11

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#7 2008-01-16 23:31:34

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#8 2008-01-17 02:25:42

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#9 2008-01-17 15:04:11

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#10 2008-01-17 15:14:00

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#11 2008-01-17 15:37:09

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#12 2008-01-17 15:46:10

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#13 2008-01-17 15:49:06

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#14 2008-01-17 18:24:36

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#15 2008-01-17 18:55:01

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#16 2008-01-17 19:01:34

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#17 2008-01-17 19:18:18

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#18 2008-01-17 19:31:02

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#19 2008-01-17 21:41:39

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#20 2008-01-17 21:50:16

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#21 2008-01-18 02:03:01

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#22 2008-01-18 03:38:22

Re: Aventures in stupidity with chmod and chattr [SOLVED]

#23 2008-01-18 06:56:53

Re: Aventures in stupidity with chmod and chattr [SOLVED]

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