In this article, we will discuss how to map SELinux users to Linux users on AlmaLinux OS, following the latest Red Hat guide for SELinux (RHEL 9). The focus is on creating a Linux user named "imran" and an SELinux user named "secman\_u" and giving them the appropriate mappings.
What is SELinux?
SELinux (Security-Enhanced Linux) is a mandatory access control (MAC) framework for Linux operating systems that allows administrators to have more precise control over who can access the system and what they can do.
SELinux Users and Linux Users
In SELinux, a user is an entity that can log in and perform operations on a system. SELinux users are different from Linux users and are used for access control. By default, SELinux users are mapped to Linux users. These mappings can be viewed using the semanage command.
SELinux User Types
SELinux user types define the set of SELinux permissions assigned to an SELinux user. The SELinux user type determines what processes an SELinux user can run and what resources they can access.
Mapping SELinux Users to Linux Users
To map an SELinux user to a Linux user, you can use the semanage command. The syntax for adding a mapping is:
semanage user -a -R "role_name" -S "type_name" -r "user_name"
Example: Mapping SELinux User "secman\_u" to Linux User "imran"
Let's create a Linux user named "imran" and an SELinux user named "secman\_u" and map them together:
# useradd -r imran
# semanage user -a -R "secman\_r" -S "secman\_t" -r "imran"
Verifying the Mapping
You can verify the mapping between a Linux user and an SELinux user using the id command:
# id -Z imran
user=imran;role=secman\_r;type=secman\_t
Removing a Mapping
To remove a mapping between a Linux user and an SELinux user, you can use the semanage command:
semanage user -d -r "user_name"
Example: Removing the Mapping for SELinux User "secman\_u"
To remove the mapping for the SELinux user "secman\_u", use the following command:
# semanage user -d -r "imran"
In this article, we discussed mapping SELinux users to Linux users in AlmaLinux OS following the latest Red Hat guide for SELinux (RHEL 9). We covered the key concepts related to SELinux users and Linux users, SELinux user types, and mapping SELinux users to Linux users. We also provided examples for adding, verifying, and removing mappings.
References
- Red Hat Enterprise Linux 9: User and Role Management
- Red Hat Enterprise Linux 9: SELinux Users and Roles
- AlmaLinux OS: User and Group Management