[CentOS] can non-owner change file group setup?

[NiftyCluster Tom Mitchell]

2009/5/12 mcclnx mcc <mcclnx at yahoo.com.tw>:
>
> We are tried to count how many files belong to certain group. Our system administrator told us "non-owner" can easy change file group name to another.  I have been tried several combination and never successful (only ROOT can change file group to other name).
>
> Does anyone know how "no-owner" can change file group name?

In general this is disallowed!

The reason is that in a system with quotas the common abuse tactic
was to give files away to someone else yet hide them down inside
your own directory.  By giving files away you might never go over quota.
Worse the poor other guy cannot find out why he is over quota.
Some things may be possible with very open directory permissions.

If directory permissions are wide open (777) is possible to take
ownership of a file
indirectly by making a copy then deleting the original.   This is not
possible on dirs
where the T bit is set.
$ ls -ld /tmp
drwxrwxrwt 39 root root 4096 2009-05-15 21:48 /tmp

Also if you are in a multi group situation you can move files between
groups that you are a member of.  This multi group case makes sense
from the accounting point of view.



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