I've been looking for a way to force usermod to modify the password/group/... files despite the user being in use.
What I do get now is this:
!! Failed to execute 'usermod --home '...' --password '...' --shell '/bin/false' 'zabbix' 2>&1':
usermod: user zabbix is currently used by process 518
I know that for being secure I need to restart the service. But this is done within a setup script. I am restarting all services at the end.
Is there any way to say --force? (well, except for modifying all necessary files.)
Thanks
If you can get root rights via sudo and are confident enough to change system files using vi then I would change the files manually.
Only a few things need to be changed in
- /etc/passwd
here you could change UID, GID, Homedirectory, Shell ...
- /etc/group
here you might need to change UID/GID as well for the username if there was a change
The File /etc/shadow will be changed automatically when using passwd to set a new password. This you can directly perform if you are root: "passwd username"
You can run usermod in a separate user namespace (with a recent enough linux), but you need to map the root user to root (otherwise you won't have permissions to modify /etc/passwd).
I.e. something like this:
unshare --user --map-root-user usermod ...
Now usermod won't find the processes running with the uid of user you are modifying.
You probably won't be able to modify the root user itself with this.
Related
I'm running a bash command on mac that moves a file to private/etc/app_name/.
sudo cp my_file.cpp private/etc/app_name/
Every time the I want to run the bash file, the OS asks for my system password.
> ./run_copy.sh
Password: *******
Is there a way to by-pass this or configure in such way that I only have to enter the password once.
Apparently, on my Macbook, I see /etc directory having symlinks with the /private/etc directory which is owned by the wheel group & root is part of that group. So, you would need to use sudo to copy to that directory.
With that said on a Linux machine, you can work around this by adding your group to a new file in the /etc/sudoers.d/<group-name> path.
<grp-name> ALL=(ALL) NOPASSWD:ALL
I've just tried this on my mac, I could copy files onto /private/etc directory without entering the sudo password prompt.
Unfortunately, this comes up with some risks as users of your group get privileged access without entering any password prompt. You might accidentally delete important system files etc.,
A more niche approach could be to allow selectively like <group> ALL = (ALL) NOPASSWD: /usr/local/bin/copy-script. This way, they can't run all scripts/commands with sudo privileges.
I have a post-commit hook in my subversion that will export a copy of my repo to a desired location for deployment. That part works fine, but it comes in with apache:apache. I need this to be changed to prod_user:prod_user. If I try to add a chown statement in my script, it will fail. If I try to use sudo, it will ask for a password that I cant give because this happening in a post-commit script. I'd like this to be as automated as possible.
My question is: How can I make this work? I need to export the contents of my repo to the production folder and convert the users/groups to match existing production users/groups.
Is there a way to pass my password as an argument to a sudo command?
Thank you for your help!
Is there a way to pass my password as an argument to a sudo command?
Don't do it, if at all possible. This will leak your password to anyone that can read the script.
But if you can't avoid it, use echo <password> | sudo -S <command> - -S makes sudo read from stdin so you can give it the password from there
Don't do any of sudo, chown, chgrp. It is not the responsibility of the uploader to fix permissions on the remote server.
Have the server administrator properly setup these, so that pushing production files from the repository works straight without messing with sudo permission at the server.
If you are the one same person, then take the time to fix the server side to avoid having a remote user elevate its privileges (even temporarily with sudo) for the sake of fixing uploaded files permissions.
Use crontab -e as root user, then you can change ownership without escalation of privileges.
Or run as prod_user and make it check out the code ...then it is already the owner of the files.
Keeping a file with the last deployment timestamp can be used to compare to HEAD timestamp.
Background
I have a long bash script which setup a large environment of interconnected software, taking several hours to complete. A few of the tasks it performs need to be run as root, for which I use sudo .... The whole process is then paused until the user notices and types in the root password. I seek some way for the user to type in the root password only at the beginning of the script, and then automatically supply it when required by sudo later.
My thoughts on possible (bad) solutions
I could store the password directly in a variable and then supply it using
echo "${root_password}" | sudo -S ...
but something tells me that this is bad practice.
Another workaround would be to force the user to run the entire script as root, but wouldn't that lead to different permissions for all of the files generated without the use of sudo?
You can prompt it at the start of your script, so it is not plain text hard saved.
Example:
#!/bin/bash
read -s -p "[sudo] sudo password for $(whoami): " pass
echo $pass | sudo -S apt-get update
help read:
-r do not allow backslashes to escape any characters
-s do not echo input coming from a terminal
I suggest you figure out all of the commands you need the script to run using SUDO, ensure the script is run by a special unprivileged user (e.g. scriptuser), and then edit /etc/sudoers to permit scriptuser to run those commands with NOPASSWD
As an example:
scriptuser ALL = NOPASSWD: /bin/kill, /usr/bin/othercommand, etc.
If you know the complete commands, including arguments, that's ideal (it means that an attacker that compromises the scriptuser account can only run those specific commands as root)
Sudo has a lot of options configurable in /etc/sudoers. If you man sudoers , you should see all of them. Forewarning: This man page is very hard to understand. Find examples. Test them. Ask on StackExchange.
Was trying to figure out how to execute a sudo command with the password as a parameter.
echo mypassword | sudo -S command
was using this reference Use sudo with password as parameter
However, on OS X it keeps say "sudo: incorrect password attempt" however that passwords is correct.
what am i doing wrong?
As pointed out in the comments already, what you're doing is a very bad idea because it leaves the password of an account laying around. Instead, if you need to run a specific command with sudo from a script, you could -- and you should -- define that single command for one specific user in such a way that its execution is allowed without having to type in the password.
So, you should edit /etc/sudoers to include an entry for your specific user for that one, single, specific command with the tag NOPASSWD:
youruser yourhostname = (root) NOPASSWD: /some/path/your/command
Or if you really don't feel like typing in the hostname of your computer, then go for:
youruser ALL = (root) NOPASSWD: /some/path/your/command
That way you will possibly leak the ability of executing that one, single command as root instead of leaking your password and with it the possibility of running any commands as root.
I'm trying to write a bash script that sets up my web development environment in ubuntu. As part of the process of setting up the script, it needs to edit files that are owned by root. It also needs to create fields in the public_html directory of the user that runs the script.
Should I therefore require that the script be run as the superuser? If it should, then how do I get it to access the current user's username? I would normally use the $USER variable, but I can't do that if the script is being run as the superuser. If I'm not the superuser, how can I get the script to request super user privileges for certain operations, while not requiring the user to type in a password for every operation that requires super user privileges.
Thanks
You can use the -E flag for sudo to preserve the environment variables, or, you can set up sudoers to preserve the environment on a per-command basis.
You can also set up the sudoers file to not ask for a password on a per-command basis, for example, to allow user xy to use smbmount without asking for a password:
xy ALL=NOPASSWD: /usr/bin/smbmount
In your case, it would be enough to just store the current user in a variable before invoking sudo, and use the already saved username:
CURRENT_USER=$USER
sudo yourscript.sh $CURRENT_USER
Then read the username from $1.
You can also use the SUDO_USER env variable, which is set to the user who is invoking sudo.
Insert a check at the top of the script:
# Make sure only root can run this script
if [[ $EUID -ne 0 ]]; then
echo "This script must be run as root" 1>&2
exit 1
fi
In this way when you run it without the root privileges you will be prompted, then you can simply rerun it the right way with:
sudo yourscript.sh
More infos at http://www.cyberciti.biz/tips/shell-root-user-check-script.html
There's a command named sudo for this purpose. It lets you specify that certain users can run certain commands as root (or another user).
If your users have root access anyway, you could just write a script that must be run as root and takes an username as parameter, instead of picking up the username.
Alternatively, one way of picking up the login username in an interactive shell is:
stat -Lc %U /proc/self/fd/0
This retrieves the ovner of the tty associated with stdin.
Just make it a setuid file. Or use sudo which is probably safer, since you can limit who gets to run it.
chmod 4755 script.sh
In Ubuntu, there's the SUDO_USER environment variable.
So, you can just run your script sudo somescript.sh and have it pull the invoking user's username $SUDO_USER.
Not sure on other dists, though.