SELinux What is SELinux? SELinux stands for Security-Enhanced Linux. Security-Enhanced Linux (SELinux) is a security architecture for Linux systems that allows administrators to have more control over who can access the system. It was originally developed by the United States National Security Agency (NSA) as a series of patches to the Linux kernel using Linux […]
posts/) SELinux. Audit Logs with SELinux Messags I’m post configuring a new RHEL 8 setup on my old PC and want to share some useful SELinux troubleshooting techniques. How To Check Audit Logs for SELinux. I had a problem with SSH not accepting keys for login. SELinux can operate in any of the 3 modes : 1. Enforced: Actions contrary to the policy are blocked and a corresponding event is logged in the audit log. 2. Permissive: Permissive mode loads the SELinux software, but doesn’t enforce the rules, only logging is performed. 3. Disabled: The SELinux is disabled entirely. gdm and xdm have SELinux awareness built into them, while login and ssh use the pam_selinux. In RHEL4 su and sudo also used pam_selinux. The way this works is the user authenticates to the system using whatever authorization mechanism is used. Linux users are mapped to the SELinux _default_ login by default, which is mapped to the SELinux unconfined_u user. However, SELinux can confine Linux users, to take advantage of the security rules and mechanisms applied to them, by mapping Linux users to SELinux users. Cache of SELinux is called AVC (Access Vector Cache) and Denial Accesses are called "AVC Denials", too. AVC Denial Log is generated via Rsyslog Service or Audit Service , so it needs either of service is running. Security-Enhanced Linux (SELinux) is a security architecture integrated into the 2.6.x kernel using the Linux Security Modules (LSM). It is a project of the United States National Security Agency (NSA) and the SELinux community. SELinux integration into Red Hat Enterprise Linux was a joint effort between the NSA and Red Hat. Troubleshooting SELinux typically involves placing SELinux into permissive mode, rerunning problematic operations, checking for access denial messages in the SELinux audit log, and placing SELinux back into enforcing mode after problems are resolved.
In permissive mode, the system acts as if SELinux is enforcing the loaded security policy, including labeling objects and emitting access denial entries in the logs, but it …
Nov 05, 2018 SELinux entries in /var/log/messages - MoonPoint Apr 24, 2016
gdm and xdm have SELinux awareness built into them, while login and ssh use the pam_selinux. In RHEL4 su and sudo also used pam_selinux. The way this works is the user authenticates to the system using whatever authorization mechanism is used.
Cache of SELinux is called AVC (Access Vector Cache) and Denial Accesses are called "AVC Denials", too. AVC Denial Log is generated via Rsyslog Service or Audit Service , so it needs either of service is running.