Open file using sudo

abhinav4 · 08-23-2012, 10:23 AM

I have a file "abc" which has 700 permission.
I want to set something in sudoers file so that a user "somename" have full privilege to it.

*What are the best practices to perform the above task.

byannoni · 08-23-2012, 10:26 AM

I don't think you can do that in sudoers, but you can do this:

Code:

chown somename abc

abhinav4 · 08-23-2012, 10:36 AM

Wee it seems that sudoers file is used only to gain access to some commands. but it cannot be used to give permission to a user to modify the contents of a file

TB0ne · 08-23-2012, 11:45 AM

Quote:

Originally Posted by abhinav4

Wee it seems that sudoers file is used only to gain access to some commands. but it cannot be used to give permission to a user to modify the contents of a file

Right...so why can't you do what you want, since you just (essentially) said that sudo can do it?

Give ONE user permission to use ONE command. That command can be "vi <some file name>". Change the ownership of the file to only allow root to access it, so then either root or that one user (via "sudo vi <some file name>") can edit it.

jefro · 08-23-2012, 04:09 PM

I think I'd have changed the group or owner to this user so that they could do some task before I gave them sudo.

TB0ne · 08-23-2012, 04:18 PM

Quote:

Originally Posted by jefro

I think I'd have changed the group or owner to this user so that they could do some task before I gave them sudo.

That's another way to do it, which will work just fine, too. However, I tend to lean towards sudo for things just like this, mainly because of the auditing purposes. A user can modify/delete their shell history, but (if you only give them sudo rights for ONE COMMAND), can't edit the sudo logs, and you can see what they did, and when.

The same thing can be accomplished either way, though, but the OP did ask about sudo specifically.

chrism01 · 08-23-2012, 06:58 PM

Unfortunately, tools like vi enable you to escape to the shell, then all bets are off ...
I'd go with user or group ownership & set the perms as needed or (more fine-grained) use an ACL.

byannoni · 08-23-2012, 07:04 PM

Quote:

Originally Posted by chrism01

Unfortunately, tools like vi enable you to escape to the shell, then all bets are off ...
I'd go with user or group ownership & set the perms as needed or (more fine-grained) use an ACL.

That is a good point, but:

Quote:

Originally Posted by TB0ne

if you only give them sudo rights for ONE COMMAND

Don't give them a command that will let them escape to the shell. Be careful, but if you know what you're doing, you won't have that problem.

chrism01 · 08-23-2012, 07:16 PM

Quote:

I want to set something in sudoers file so that a user "somename" have full privilege to it.

Need the OP to define 'full privilege'.

In any case my point stand; sudo is designed to control what cmds/tools you can run.
It cannot protect files and many cmds have a way to break out into the shell, even if its just ctrl-C or similar.
See the Security Notes here http://linux.die.net/man/8/sudo

abhinav4 · 08-24-2012, 07:02 AM

Quote:

somename ALL=/root/abc

Putting above line in sudoers file made me achieve what i was trying, and I do not think it is a security hole.

iamwilliam · 08-24-2012, 08:39 AM

I think you need to use FACL (File Access Lists) to achieve what you want.

You need to make sure that the filesystem has been mounted with the acl option.

Code:

[root@docserver ~]# cat /etc/fstab
/dev/VolGroup00/LogVol00 /                       ext3    defaults,acl        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2

Remount the filesystem

Code:

mount -o remount /

Verify the options have been applied

Code:

[root@server ~]# mount -l
/dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw,acl)

Now user2 has "full control" over secretfile

Code:

 setfacl -m u:user2:x /home/user1/
 setfacl -m u:user2:rwx /home/user1/secretfile

abhinav4 · 08-24-2012, 09:43 AM

Quote:

Originally Posted by iamwilliam

I think you need to use FACL (File Access Lists) to achieve what you want.

You need to make sure that the filesystem has been mounted with the acl option.

Code:

[root@docserver ~]# cat /etc/fstab
/dev/VolGroup00/LogVol00 /                       ext3    defaults,acl        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2

Remount the filesystem

Code:

mount -o remount /

Verify the options have been applied

Code:

[root@server ~]# mount -l
/dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw,acl)

Now user2 has "full control" over secretfile

Code:

 setfacl -m u:user2:x /home/user1/
 setfacl -m u:user2:rwx /home/user1/secretfile

Thanks but the whole question was to do it from sudoers file