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useradd w/o write permission on /etc/passwd

 
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Operating Systems Linux Red Hat useradd w/o write permission on /etc/passwd
# 1  
Old 01-25-2012
useradd w/o write permission on /etc/passwd

Hi
root user creates a user using the useradd command. This command creates an entry in the /etc/passwd file. /etc/passwd file has rw permission for the root user. Now, if I happen to remove the w permission for the root user, useradd command still is successfully creating entry in the /etc/passwd file. I understand there is nothing related to suid here.

Please advice how this works?
# 2  
Old 01-25-2012
simply put, root gets to break the rules.
This User Gave Thanks to Corona688 For This Post:
# 3  
Old 01-25-2012
/etc/passwd should have permissions 444 .
The "passwd" command has SUID permissions as root which is how users can update their password.
# 4  
Old 01-25-2012
Quote:
Originally Posted by arran
i want to know why you want to take w permission from root?? root is your supper user and you will take back permission from root then which superuser can add user???
Quote:
Originally Posted by Corona688
root gets to break the rules.
As long as it's not asking for something physically impossible, root can do it.
Code:
# as root
$ touch /tmp/asdf
$ chmod 000 /tmp/asdf
$ echo asdf > /tmp/asdf
$ cat /tmp/asdf
asdf
$ ls -l /tmp/asdf
---------- 1 root root 5 Jan 25 14:16 /tmp/asdf
$


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