There are two components to the policy, the binary tree and the source
tree. The binary tree comes from the
selinux-policy-<policyname>
package and supplies the binary policy file. Alternately, the binary
policy can be built from source when the
selinux-policy-<policyname>-sources
package is installed. For Red Hat Enterprise Linux 4 the
<policyname> is targeted. Directory conventions
for this guide are explained in Section 3 Conventions for SELinux Directories and Files.
/etc/selinux/targeted/ — this is the root folder
for the targeted policy, and contains both the binary and source
trees.
/etc/selinux/targeted/policy/ — the binary policy file
policy.<XY> is here. In
this guide, the variable $SELINUX_POLICY/ is used for this directory.
/etc/selinux/targeted/src/policy/ — this is the location of
the policy source tree. For details about these sub-directories, read
Section 3.2 Files and Directories of the Targeted Policy. In this guide, the
variable $SELINUX_SRC/ is used for this directory.
/etc/selinux/targeted/contexts/ — location of the
security context information and configuration files, which are used
during runtime by various applications. This directory contains:
*_context* and
default_type — various contexts used by
applications, such as the userhelper_context
used by userhelper.
files/* — the file
file_contexts contains the default contexts
for the whole file system. This is what
restorecon references when relabeling. The
file media contains the default contexts for
media devices such as the CD-ROM and floppy disk.
users/* — in the targeted policy,
only the file root is in this directory.
These files are used for determining context on login, which is
system_r:unconfined_t for root.
booleans — this is where the runtime
Booleans are configured. This is the canonical configuration file
when Boolean values are changed.
To help applications that need the various SELinux paths,
libselinux has a number of functions that return the
paths to the different configuration files and directories. This keeps
applications from having to hard code the paths, especially since the active
policy location is dependent on the setting in
/etc/selinux/config. The list of functions is
available from the manual page which you can view with the command
man 3 selinux_binary_policy_path.
