Resolving SELinux Boot Error
SELinux (Security-Enhanced Linux) is the feature included in Linux that offers several security policies using LSM (Linux Security Modules) in Linux Kernel. In other words, it is the set of security modifications that you can apply to your Linux system. The policies applied allow you to set your system as per desired configuration. SELinux should not be misinterpreted as a different Linux distribution.
At times, you encounter errors with a SELinux using system preventing it from boot. Such behavior could occur due to file system inconsistencies. Thus, to resolve the issue, you might need to reformat the hard disk, which requires data restoration at a later stage. However, if you find that present data backup is not valid enough that it could give required results, it is recommended to immediately use advanced Linux Recovery applications.
As an example, while using your system, you receive an unexpected SELinux notification and the system hangs. Upon next restart, you encounter the similar error message displaying on screen and the system fails to boot:
'SELinux: policydb magic number <number1> does not match the expected magic number <number2'
Further, when you forcefully shut down the system, you get a report that the file system is being checked.
In Debian system, policies are placed in /etc/selinux/ and in red Hat the location is /etc/security/selinux/src/policy
Cause
Under Linux, system identifies different files to be executed by their corresponding magic number. The above error occurs if it could not find expected magic number for the particular policy.
Solution
To fix such errors, you need to follow these steps:
' Try running fsck-y to manually repair the file system. To execute the command, login as root in single user mode.
' If problem continues, reinstall Linux and restore from backup (if present and valid)
You might face backup unavailability and damage issues. In such situations, you are recommended to use advanced Data Recovery Linux applications. Such software employ powerful scanning procedures to locate the missing data and restore it at a safe location. Linux Recovery utilities provide you interactive user interface and several advanced features to assist recovery.
Stellar Phoenix Linux Data Recovery is a full-fledged data recovery tool for Linux-based system. It supports Data Recovery Linux for Ext2, Ext3, and ReiserFS file systems. The application empowers you with features such as, RAW File Recovery, File Filter, Append File Header etc. It is compatible with almost all Linux distributions including Gentoo, SlackWare, Debian, Mandrake, Ubuntu, SUSE etc.
About the Author:
Allen a student of Mass Communication doing research on data recovery software. He is also a freelancer for http://www.stellarinfo.com