We are using sudo users with limited commands to execute and assigned default home directory /home/sudouser but if that particular sudo user is running command cd \ its changing the directory to the main root directory /. This behaviour is totally insecure for us.
We need it such that if the sudo user is entering cd / or cd it changes directory to their home directory /home/sudouser
Please let us know how we can implement this?
Don't ever try to restrict a sudo user to only a directory or a command, a sudo user can by definition do what he wants.
In your case, having a script that assigns the home directory is I think a better idea. To solve the trouble of permissions look for the suid bit in permissions: http://www.linuxnix.com/suid-set-suid-linuxunix/
For example: create a sh file that has the following permissions: "-rwsr--r--" that is owned by root and as a group that can be accessed by the user whom you want to use the script.
Then in the file you create a simple script to execute the command to change default directory with let's say two parameters (username and directory)
Is it possible avoid sudo word while executing the higher privileged commands to a non-root user via a sudo policy such non-root users should not be able to know that he is executing higher privileged commands and also the usage of sudo might be complex.
Example:
Normal Execution of Sudo Command.
$ sudo -u root /usr/bin/tcpdump
non-root users should execute tcpdump like below.
$ tcpdump
Thanks in advance.
Note: I have defined a Sudo Policy for non-root users. So, when a non-root user executes tcpdump, in the backend it should execute as
sudo -u root tcpdump.
Yes. It is possible.
You should:
1- Create a new specific new group where some users would belong:
groupadd nonroot
2- Add your privileged users to that group:
2.1- Edit /etc/group:
vim /etc/group
2.2- Find the line of new created group. It should look like that:
nonroot:x:127:
2.3- At the end, add your privilaged users:
nonroot:x:127:user1,user2
3- Change the group of your binary:
chgrp nonroot /usr/bin/tcpdump
4- Give group execution permissions to the binary:
chmod g+x /usr/bin/tcpdump
You have to have in count that if the binary reads, writes or executes files which user1 has no permissions, you'll have modify them in the same way.
If you cannot change the group of the binary, check the right answer of post bellow, which is a similar way:
Allow users of a certain group to run a command without sudo
Hope it helps.
NOTE: Commands may differ between different linux/unix distros.
I can see at least two possibilities:
Wrap it in a script (an alias is also possible, but if users can use different shells or just start them manually, it can turn into a maintenence hell)
Set the suid bit on tcpdump, but that means everyone who can invoke tcpdump always does so as the owner.
You might want to explore using sudoers file.
Using CentOS as an example (should be similar for Debian), create a file within sudoers.d with the relevant name, e.g. tcpdump and include the following:
user ALL=NOPASSWD: /usr/bin/tcpdump command
Replace the user and command to suit your purpose. You can find out more here.
This coupled with a alias tcpdump='sudo tcpdump for the user should fit your use case.
I have a script that runs iftop in text mode, cuts down the output to what I'm concerned in, and saves it to a text file along with the output of the date command (I am monitoring network usage on various interfaces over time). Only problem I'm having is I'm trying to run my script every 15 minutes via the crontab, and in order to run the iftop command I need sudo permissions. Does anyone know some way to change the permissions of iftop to make it so I don't need sudo permissions?
Alternatively if I can give the script the ability to run the command with sudo that would be fine by me as well. I tried adding the script to the sudoers file via sudo visudo and adding the line:
user ALL=(ALL) NOPASSWD: /home/user/network_usage.sh
but that didn't work...perhaps a result of executing from the crontab?
Thanks,
-Eric
A more granular approach would be to use:
# setcap cap_net_raw=eip $(which iftop)
This lets iftop capture packets but does not give the process full root privileges. In case of a security problem or bug with "iftop" its side effects would be much more limited.
Related: https://unix.stackexchange.com/questions/189750/how-can-i-run-script-without-root-to-sniff-network-libpcap
If you have root access on the machine the quick and dirty way:
chmod +s $(which iftop)
This will make it run w/ root privileges no matter who invokes it.
But I still think your sudo like should work.
You may use root's crontab to run the script.
If instead of crontab -e you use sudo crontab -e you will edit root's crontab. Tasks specified in that file will run under root's account and privileges.
Alternatively, you can set the setuid access flag for your script file. To do so first change the owner of the file to root, then enable setuid like this:
sudo chown root /home/user/network_usage.sh
sudo chmod +s-w /home/user/network_usage.sh
The setuid bit makes an executable file run with the effective UID of its owner.
Regardless of what approach you take, be very careful.
Make your script owned by root and don't let any other user write to it, otherwise it could ease a privilege escalation.
Be aware of the side effects of your setuid programs. If the script has setuid and may create or modify files, it might be used by someone else to modify or create files they aren't supposed to. Always check the manual before giving setuid to any program you haven't written.
For some reason I need, as user, to run without sudo a script script.sh which needs root privileges to work.
I saw as the only solution to put sudo INSIDE script.sh. Let's take an example :
script.sh :
#!/bin/sh
sudo apt-get update
Of course, if I execute this script, I get a prompt asking me for a password. Then I added to my sudoers file (at the end to override everything else) :
user ALL=(ALL:ALL) NOPASSWD:/path/to/script.sh
By the way, I also tried the line :
user ALL=(ALL) NOPASSWD:/path/to/script.sh
(I think I didn't fully understand the difference)
But this doesn't solve my problem if I don't use sudo to execute this script :
# ./script.sh
[sudo] password for user:
# sudo ./script.sh
Starts updating...
Well, so I say to myself "Ok, that means that if I have a file refered in sudoers as I did, it will work without prompt only if I call him with sudo, what is not what I want".
So, ok, I create another script script2.sh as following :
script2.sh
#!/bin/sh
sudo /path/to/script.sh
In fact it works. But I am not truly satisfied of this solution, particularly by the fact that I have to use 2 scripts for every command.
This post is then for helping people having this problem and searching for the same solution (I didn't find a good post on it), and perhaps have better solutions coming from you guys.
Feel free to share your ideas !
EDIT 1 :
I want to insist on the fact that this "apt-get update" was just an example FAR from whhat my script actually is. My script has a lot of commands (with some cd to root-access-only config files), and the solution can't be "Well, just do it directly with apt-get".
The principle of an example is to help the understanding, not to be excuse to simplify the answer of the general problem.
From my blog: IDMRockstar.com:
The kicker is that sometimes, I need to run commands as root. Here's the quick and dirty way I accomplish that without divulging the passwords:
#! /bin/bash
read -s -p "Enter Password for sudo: " sudoPW
echo $sudoPW | sudo -S yum update
This way the user is prompted for the password (and hidden from terminal) and then passed into commands as needed, so I'm not running the entire script as root =)
If you have a better, way, I'd love to hear it! I'm not a shell scripting expert by any means.
Cheers!
.: Adam
If you want to run sudo /usr/bin/apt-get update without a password, you need to have the sudoers entry:
user ALL=(ALL:ALL) NOPASSWD:/usr/bin/apt-get update
For the larger issue of the script as a whole, there are two possible approaches:
Approach 1
For each command in the script that needs sudo, create a line in sudoers specifically for that command. In this case, the script can be called normally:
./script1.sh
Approach 2
Place a line in sudoers for the script as a whole. When this is done, the individual commands do not need sudo. However, sudo must be used to start the script as in:
sudo ./script.sh
If your password isn't something you want to be very secure about, (maybe some testing server in the company etc.) you can elevate to sudo in the script via echo like:
echo YourPasswordHere | sudo -S Command
The prompt still prints the "enter password" text to output though. So don't expect it to be neat.
See this Askubuntu post
As you noted, the file that must appear in the sudoers configuration is the one that is launched by sudo, and not the one that runs sudo.
That being said, what we often do, is having something like
user ALL=(ALL:ALL) NOPASSWD:/path/to/script.sh
in the sudo configuration, where script.sh has all the commands that the script has to do.
Then we define either a Bash function or an alias so that script.sh is actually
sudo /path/to/script.sh
The only issue is if some commands must not be run as root, you need to insert some su - user -c "command" commands in the script.
In new /etc/sudoers.d/apt-get file, put single line:
user ALL=(ALL:ALL) NOPASSWD:/usr/bin/apt-get update
Fully qualified path to executable is required here.
Then use following in your script:
sudo apt-get update
Here, fully specified name is not required. Sudo uses PATH environment variable for executable resolution.
While changing and checking sudoers configuration, be sure to keep another root session open for error recovery.
I suggest you look at the sudo environment variables - specifically you can use (and check for) $SUDO_USER. Call your script with sudo (1 entry in sudoers), then do user stuff as SUDO_USER and root stuff as root.
As mentioned by Basilevs you need to add your user to the sudoers file in order to avoid that sudo commands in the script get stuck awaiting the password.
On Ubuntu 16, there is a simpler way: just add the user to the sudo group, like this:
sudo usermod -aG sudo *username*
From then on, it should work like a charm.
Note:
This works only on the condition that the following line is in file /etc/sudoers:
%sudo ALL=NOPASSWD: ALL
(such line gives passwordless sudo privileges at group level, in this case to the sudo group)
(if this line is not present and you want to add it, make sure you use visudo)
Simply, in order to execute commands as root you must use su (even sudo uses su)
As long as you execute sudo ./script2.sh successfully just instead :
sudo su
"#" //commands as root here
"#" exit
//commands as use here
you can make it a shell function with the name sudo, but no other better way i think,however it's the case with scripts inti,rc android ..etc
must be tidy ;)
however this requires you to put NOPASSWD: su wich is totaly secure indeed
any way here just lacks POISX permissions principle which is filtering so dont enable something to all users or vice versa
simply, call sudo as much as you want with no additional thing then:
chown root script.sh
chmod 0755 script.sh
chgrp sudo script.sh
"make root owner of .sh"
"make it read only and exec for others"
"and put it in sudo group"
of course under sudo
that's it
I am not sure whether this is a Sphinx question or a Linux question.
Anyway, I am running Sphinx on my CentOS server box.
I successfully managed to change the ownership of some Sphinx-related files and directories as I want only root and the Apache group to be able to read those information:
chown root.apache /etc/sphinx/sphinx.conf
chmod 640 /etc/sphinx/sphinx.conf
chown -R root.apache /var/lib/sphinx
chmod -R 750 /var/lib/sphinx
My problem is when Sphinx generates the files containing the index in the directory /var/lib/sphinx, they have ownership
root:root
How can I make them have permission
root:apache
?
The Sphinx documentation doesn't mention about that.
Thanks.
Set SETGID for directory /var/lib/sphinx/:
root#centos:~# chmod g+s /var/lib/sphinx/
This way, all created file in directory /var/lib/sphinx/ will inherit group from parent.
If sphinx is not messing with ownership by it self (I guess it't not) then this will work.
You can read more here about SETGID on directories.
Or you can run the cron job as the user sphinx rather than as root, either by adding sudo -u sphinx in the existing crontab entry, or by removing it from root's crontab and adding it to the appropriate user's crontab. (Perhaps you should report this as a bug against the package, if you are using a packaged version.)