Permissions question

sammckee · 09-23-2003, 09:59 AM

Can root always do anything with any file? Is it possible for the root user to lock himself out of a file, unable to access it or change its permissions back?

DrOzz · 09-23-2003, 10:11 AM

i had a somewhat similiar question a few months back, but it was related to editing the /etc/passwd file and resetting the roots password....and i thought it was a major flaw, so i asked how can this be avoided and here is the answer i got :

Quote:

There are ways to keep anyone from overwritting current files or even appending to them, one way:
chattr +i
On the file. Root cannot even append to the file if this is applied. You will have to:
chattr -i
To remove that restriction to actually change the files. It's a quick and easy thing to do to:
/etc/passwd
/etc/group
/etc/shadow

Just remember you did it should you choose to. This is obviously un-doable should one gain root access, but this will keep them from gaining root access an easier way.

so i would assume chattr +i would stop the root and anyone else from doing anything to a file, and in turn lock them out...

david_ross · 09-23-2003, 10:16 AM

Root will always have permission to change permissions so this should never happen. It is possible to write protect a fiel to the root user but you will be able to change the permissions back.

RolledOat · 09-23-2003, 10:55 AM

You can make it so that root can't accidentally delete or update a file, which is what I have done for some files, however, in vi, when I really want to
Esc:w! will override the current permissions.

RO

P.S. But accidentally hosing your system is the #1 reason not to run as root. Well, maybe tied for #1 with security risk if you are on the internet. See Mr Ross' sig, well, don't try that as root unless you really want to re-install your OS or want to see just how long it takes your box to die.
Six simple characters on the command line. Now that is power!