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Content Specification
Security-Enhanced Linux Preface
On Linux operating systems, everything is represented as a file. For example, a hard disk can be represented as the /dev/hda file, and processes, such as Mozilla Firefox, are represented as files in the proc file system (/proc). These files are called objects. Linux operating systems use a Discretionary Access Control (DAC) system, that defines access to these objects. Users have access to change permissions for files and directories that they own. They could, for example, make their home directory world-readable, potentially allowing access to privileged information from other users, or giving processes, such as a Web server, access to serve these files.