
Fedora Linux System Administration
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SELinux is a labeling system, which tells us that each file, directory, or object in the system has a corresponding label. Each file, process, directory, and port has a special security label called an SELinux context. A context is a tag name used by the SELinux policy to determine whether a process can access a file, directory, or port. Policies control the interaction between these elements. By default, the policy does not allow any interaction unless an explicit rule grants access. If no permission rule exists, access is not allowed. The Linux kernel enforces these rules.
SELinux contexts have different labels in their format, separated by colons: user, role, type, and sensitivity level. They are formed as follows:
user:role:type:level (optional)
Note
The sensitivity level is the part that is optional.
The targeted policy bases its rules on the third context component: the type context. Type context names usually end with _t
.
Let’...