###############################################################################
#
# Copyright (C) 2006, 2010 Red Hat, Inc. All Rights Reserved.
# Written by David Howells (dhowells@redhat.com)
#            Karl MacMillan (kmacmill@redhat.com)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version
# 2 of the License, or (at your option) any later version.
#
###############################################################################

#
# This security policy governs access by the CacheFiles kernel module and
# userspace management daemon to the files and directories in the on-disk
# cache, on behalf of the processes accessing the cache through a network
# filesystem such as NFS
#
policy_module(cachefilesd,1.0.17)

###############################################################################
#
# Declarations
#
require { type kernel_t; }

#
# Files in the cache are created by the cachefiles module with security ID
# cachefiles_var_t
#
type cachefiles_var_t;
files_type(cachefiles_var_t)

#
# The /dev/cachefiles character device has security ID cachefiles_dev_t
#
type cachefiles_dev_t;
dev_node(cachefiles_dev_t)

#
# The cachefilesd daemon normally runs with security ID cachefilesd_t
#
type cachefilesd_t;
type cachefilesd_exec_t;
domain_type(cachefilesd_t)
init_daemon_domain(cachefilesd_t, cachefilesd_exec_t)

#
# The cachefilesd daemon pid file context
#
type cachefilesd_var_run_t;
files_pid_file(cachefilesd_var_run_t)

#
# The CacheFiles kernel module causes processes accessing the cache files to do
# so acting as security ID cachefiles_kernel_t
#
type cachefiles_kernel_t;
domain_type(cachefiles_kernel_t)
domain_obj_id_change_exemption(cachefiles_kernel_t)
role system_r types cachefiles_kernel_t;

###############################################################################
#
# Permit RPM to deal with files in the cache
#
rpm_use_script_fds(cachefilesd_t)

###############################################################################
#
# cachefilesd local policy
#
# These define what cachefilesd is permitted to do.  This doesn't include very
# much: startup stuff, logging, pid file, scanning the cache superstructure and
# deleting files from the cache.  It is not permitted to read/write files in
# the cache.
#
# Check in /usr/share/selinux/devel/include/ for macros to use instead of allow
# rules.
#
allow cachefilesd_t self : capability { setuid setgid sys_admin dac_override };

# Basic access
files_read_etc_files(cachefilesd_t)
libs_use_ld_so(cachefilesd_t)
libs_use_shared_libs(cachefilesd_t)
miscfiles_read_localization(cachefilesd_t)
logging_send_syslog_msg(cachefilesd_t)
init_dontaudit_use_script_ptys(cachefilesd_t)
term_dontaudit_use_generic_ptys(cachefilesd_t)
term_dontaudit_getattr_unallocated_ttys(cachefilesd_t)

# Allow manipulation of pid file
allow cachefilesd_t cachefilesd_var_run_t:file create_file_perms;
manage_files_pattern(cachefilesd_t,cachefilesd_var_run_t, cachefilesd_var_run_t)
manage_dirs_pattern(cachefilesd_t,cachefilesd_var_run_t, cachefilesd_var_run_t)
files_pid_file(cachefilesd_var_run_t)
files_pid_filetrans(cachefilesd_t,cachefilesd_var_run_t,file)

# Allow access to cachefiles device file
allow cachefilesd_t cachefiles_dev_t : chr_file rw_file_perms;

# Allow access to cache superstructure
allow cachefilesd_t cachefiles_var_t : dir { rw_dir_perms rmdir };
allow cachefilesd_t cachefiles_var_t : file { getattr rename unlink };

# Permit statfs on the backing filesystem
fs_getattr_xattr_fs(cachefilesd_t)

###############################################################################
#
# When cachefilesd invokes the kernel module to begin caching, it has to tell
# the kernel module the security context in which it should act, and this
# policy has to approve that.
#
# There are two parts to this:
#
#   (1) the security context used by the module to access files in the cache,
#       as set by the 'secctx' command in /etc/cachefilesd.conf, and
#
allow cachefilesd_t cachefiles_kernel_t : kernel_service { use_as_override };

#
#   (2) the label that will be assigned to new files and directories created in
#       the cache by the module, which will be the same as the label on the
#       directory pointed to by the 'dir' command.
#
allow cachefilesd_t cachefiles_var_t : kernel_service { create_files_as };

###############################################################################
#
# cachefiles kernel module local policy
#
# This governs what the kernel module is allowed to do the contents of the
# cache.
#
allow cachefiles_kernel_t self:capability { dac_override dac_read_search };
allow cachefiles_kernel_t initrc_t:process sigchld;

manage_dirs_pattern(cachefiles_kernel_t,cachefiles_var_t, cachefiles_var_t)
manage_files_pattern(cachefiles_kernel_t,cachefiles_var_t, cachefiles_var_t)

fs_getattr_xattr_fs(cachefiles_kernel_t)

dev_search_sysfs(cachefiles_kernel_t)