Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Programming
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Databases
Mail Systems
openSolaris
Eclipse Documentation
Techotopia.com
Virtuatopia.com

How To Guides
Virtualization
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Windows
Problem Solutions

  




 

 

7.3. Fixing Problems

The following sections help troubleshoot issues. They go over: checking Linux permissions, which are checked before SELinux rules; possible causes of SELinux denying access, but no denials being logged; manual pages for services, which contain information about labeling and Booleans; permissive domains, for allowing one process to run permissive, rather than the whole system; how to search for and view denial messages; analyzing denials; and creating custom policy modules with audit2allow.

7.3.1. Linux Permissions

When access is denied, check standard Linux permissions. As mentioned in Chapter 2, Introduction , most operating systems use a Discretionary Access Control (DAC) system to control access, allowing users to control the permissions of files that they own. SELinux policy rules are checked after DAC rules. SELinux policy rules are not used if DAC rules deny access first.
If access is denied and no SELinux denials are logged, use the ls -l command to view the standard Linux permissions:
$ ls -l /var/www/html/index.html
-rw-r----- 1 root root 0 2009-05-07 11:06 index.html
In this example, index.html is owned by the root user and group. The root user has read and write permissions (-rw), and members of the root group have read permissions (-r-). Everyone else has no access (---). By default, such permissions do not allow httpd to read this file. To resolve this issue, use the chown command to change the owner and group. This command must be run as the Linux root user:
# chown apache:apache /var/www/html/index.html
This assumes the default configuration, in which httpd runs as the Linux apache user. If you run httpd with a different user, replace apache:apache with that user.
Refer to the Fedora Documentation Project "Permissions" draft for information about managing Linux permissions.

 
 
  Published under the terms of the GNU General Public License Design by Interspire