An in-depth discussion of the three working modes of SELinux

Detailed explanation of the three working modes of SELinux

SELinux is a mandatory access control (MAC) technology designed to enhance the security of Linux systems. It uses tags to mark resources in the system (such as files, processes, and ports) and defines policies to control process access to these resources. In SELinux, there are three main working modes: forced mode, elastic mode and harmless mode. This article will introduce these three working modes in detail and provide specific code examples.

1. Enforcing Mode

In enforcing mode, SELinux will enforce the predefined access policy. If the process attempts to access unauthorized resources, the access will be blocked. is rejected and logged in the audit log. In this mode, the SELinux protection mechanism cannot be bypassed even if the system administrator wishes. Administrators need to configure and customize policies based on actual needs.

Code example:
In enforcement mode, you can check the status of SELinux through the following command:

sestatus

2. Permissive Mode

In elastic mode, SELinux will also execute the predefined access policy, but will not deny any access and will not record it in the audit log. This mode can be used to test policies to understand which access will be denied in order to adjust the SELinux configuration. Administrators can make policy adjustments while keeping the system running.

Code example:
In elastic mode, you can check the status of SELinux through the following command:

sestatus

3. Harmless Mode (Disabled Mode)

In harmless mode, SELinux will be completely disabled and the system will return to the traditional Unix permission control mode. Access control in the system relies entirely on file permissions and user permissions and is no longer protected by SELinux. This mode is suitable for environments with low system security requirements, but is not recommended for use in production environments.

Code example:
In harmless mode, you can check the status of SELinux through the following command:

sestatus

Summary:

In actual applications, according to the system Requirements and security level, you can choose the appropriate SELinux working mode. Enforcement mode provides the highest level of security, but requires careful configuration of policies; elastic mode can help administrators understand system access and adjust policies; harmless mode simplifies the complexity of system management to the greatest extent, but sacrifices certain security. Administrators should choose the appropriate working mode based on the actual situation and perform necessary configuration and monitoring to ensure system safety and reliability.

The above is a detailed explanation of the three working modes of SELinux. I hope it will be helpful to readers.

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