selinux-policy/refpolicy/policy/modules/services/cron.te

policy_module(cron, 1.0)

########################################
#
# Declarations
#
attribute cron_spool_type;

type anacron_exec_t;
files_type(anacron_exec_t)

type cron_spool_t;
files_type(cron_spool_t)

type crond_t; #, privmail
type crond_exec_t;
init_daemon_domain(crond_t,crond_exec_t)
domain_wide_inherit_fd(crond_t)

type crond_log_t;
logging_log_file(crond_log_t)

type crond_tmp_t;
files_tmp_file(crond_tmp_t)

type crond_var_run_t;
files_pid_file(crond_var_run_t)

type crontab_exec_t;
files_type(crontab_exec_t)

type system_cron_spool_t;
type system_crond_t; #, privmail
init_daemon_domain(system_crond_t,anacron_exec_t)
corecmd_shell_entry_type(system_crond_t)
role system_r types system_crond_t;

type system_crond_lock_t;
files_lock_file(system_crond_lock_t)

type system_crond_tmp_t;
files_tmp_file(system_crond_tmp_t)

########################################
#
# Cron Local policy
#

allow crond_t self:capability { dac_override setgid setuid net_bind_service sys_nice };
dontaudit crond_t self:capability { sys_resource sys_tty_config };
allow crond_t self:process ~{ ptrace setcurrent setexec setfscreate setrlimit execmem dyntransition };
allow crond_t self:process setexec;
allow crond_t self:fd use;
allow crond_t self:fifo_file rw_file_perms;
allow crond_t self:unix_dgram_socket create_socket_perms;
allow crond_t self:unix_stream_socket create_stream_socket_perms;
allow crond_t self:unix_dgram_socket sendto;
allow crond_t self:unix_stream_socket connectto;
allow crond_t self:shm create_shm_perms;
allow crond_t self:sem create_sem_perms;
allow crond_t self:msgq create_msgq_perms;
allow crond_t self:msg { send receive };

allow crond_t crond_log_t:file create_file_perms;

allow crond_t crond_var_run_t:file create_file_perms;
files_create_pid(crond_t,crond_var_run_t)

allow crond_t crond_tmp_t:dir create_dir_perms;
allow crond_t crond_tmp_t:file create_file_perms;
files_create_tmp_files(crond_t, crond_tmp_t, { file dir })

allow crond_t cron_spool_t:dir r_dir_perms;
allow crond_t cron_spool_t:file r_file_perms;
allow crond_t system_cron_spool_t:dir r_dir_perms;
allow crond_t system_cron_spool_t:file r_file_perms;

kernel_read_kernel_sysctl(crond_t)
dev_read_sysfs(crond_t)
selinux_get_fs_mount(crond_t)
selinux_validate_context(crond_t)
selinux_compute_access_vector(crond_t)
selinux_compute_create_context(crond_t)
selinux_compute_relabel_context(crond_t)
selinux_compute_user_contexts(crond_t)

dev_read_urand(crond_t)

fs_getattr_all_fs(crond_t)
fs_search_auto_mountpoints(crond_t)

term_dontaudit_use_console(crond_t)

# need auth_chkpwd to check for locked accounts.
auth_domtrans_chk_passwd(crond_t)

corecmd_exec_shell(crond_t)
corecmd_list_sbin(crond_t)

domain_use_wide_inherit_fd(crond_t)

files_read_etc_files(crond_t)
files_read_generic_spools(crond_t)

init_use_fd(crond_t)
init_use_script_pty(crond_t)

libs_use_ld_so(crond_t)
libs_use_shared_libs(crond_t)

logging_send_syslog_msg(crond_t)

seutil_read_config(crond_t)
seutil_read_default_contexts(crond_t)
seutil_sigchld_newrole(crond_t)

miscfiles_read_localization(crond_t)

userdom_use_unpriv_users_fd(crond_t)

ifdef(`distro_redhat', `
	# Run the rpm program in the rpm_t domain. Allow creation of RPM log files
	# via redirection of standard out.
	optional_policy(`rpm.te', `
		rpm_manage_log(crond_t)
	')
')

ifdef(`targeted_policy', `
	term_dontaudit_use_unallocated_tty(crond_t)
	term_dontaudit_use_generic_pty(crond_t)
	files_dontaudit_read_root_file(crond_t)
')

tunable_policy(`fcron_crond', `
	allow crond_t system_cron_spool_t:file create_file_perms;
')

optional_policy(`nis.te',`
	nis_use_ypbind(crond_t)
')

optional_policy(`nscd.te',`
	nscd_use_socket(crond_t)
')

optional_policy(`rpm.te',`
	# Commonly used from postinst scripts
	rpm_read_pipe(crond_t)
')

optional_policy(`udev.te', `
	udev_read_db(crond_t)
')

ifdef(`TODO',`
# NB The constraints file has some entries for crond_t, this makes it
# different from all other domains...

optional_policy(`rhgb.te', `
rhgb_domain(crond_t)
')

# Read from /var/spool/cron.
allow crond_t var_lib_t:dir search;
allow crond_t default_t:dir search;

# crond tries to search /root.  Not sure why.
allow crond_t sysadm_home_dir_t:dir r_dir_perms;

# to search /home
allow crond_t user_home_dir_type:dir r_dir_perms;
') dnl endif TODO

########################################
#
# System cron process domain
#

allow system_crond_t self:capability { dac_override dac_read_search chown setgid setuid fowner net_bind_service fsetid };
allow system_crond_t self:process { signal_perms setsched };
allow system_crond_t self:fifo_file rw_file_perms;
allow system_crond_t self:passwd rootok;

# The entrypoint interface is not used as this is not
# a regular entrypoint.  Since crontab files are
# not directly executed, crond must ensure that
# the crontab file has a type that is appropriate
# for the domain of the user cron job.  It
# performs an entrypoint permission check
# for this purpose.
allow system_crond_t system_cron_spool_t:file entrypoint;

allow system_crond_t system_cron_spool_t:file r_file_perms;

# Permit a transition from the crond_t domain to this domain.
# The transition is requested explicitly by the modified crond 
# via setexeccon.  There is no way to set up an automatic
# transition, since crontabs are configuration files, not executables.
allow crond_t system_crond_t:process transition;
dontaudit crond_t system_crond_t:process { noatsecure siginh rlimitinh };
allow crond_t system_crond_t:fd use;
allow system_crond_t crond_t:fd use;
allow system_crond_t crond_t:fifo_file rw_file_perms;
allow system_crond_t crond_t:process sigchld;

# Write /var/lock/makewhatis.lock.
allow system_crond_t system_crond_lock_t:file create_file_perms;
files_create_lock(system_crond_t,system_crond_lock_t)

# write temporary files
allow system_crond_t system_crond_tmp_t:file create_file_perms;
files_create_tmp_files(system_crond_t,system_crond_tmp_t)

# write temporary files in crond tmp dir:
allow system_crond_t crond_tmp_t:dir rw_dir_perms;
type_transition system_crond_t crond_tmp_t:file system_crond_tmp_t;

# Read from /var/spool/cron.
allow system_crond_t cron_spool_t:dir r_dir_perms;
allow system_crond_t cron_spool_t:file r_file_perms;

# Access crond log files
allow system_crond_t crond_log_t:file create_file_perms;
logging_create_log(system_crond_t,crond_log_t)

kernel_read_kernel_sysctl(system_crond_t)
kernel_read_system_state(system_crond_t)
kernel_read_software_raid_state(system_crond_t)

# ps does not need to access /boot when run from cron
bootloader_dontaudit_search_boot(system_crond_t)

corenet_tcp_sendrecv_all_if(system_crond_t)
corenet_raw_sendrecv_all_if(system_crond_t)
corenet_udp_sendrecv_all_if(system_crond_t)
corenet_tcp_sendrecv_all_nodes(system_crond_t)
corenet_raw_sendrecv_all_nodes(system_crond_t)
corenet_udp_sendrecv_all_nodes(system_crond_t)
corenet_tcp_sendrecv_all_ports(system_crond_t)
corenet_udp_sendrecv_all_ports(system_crond_t)
corenet_tcp_bind_all_nodes(system_crond_t)
corenet_udp_bind_all_nodes(system_crond_t)

dev_getattr_all_blk_files(system_crond_t)
dev_getattr_all_chr_files(system_crond_t)
dev_read_urand(system_crond_t)

fs_getattr_all_fs(system_crond_t)
fs_getattr_all_files(system_crond_t)

corecmd_exec_bin(system_crond_t)
corecmd_exec_sbin(system_crond_t)

domain_exec_all_entry_files(system_crond_t)

files_exec_etc_files(system_crond_t)
files_read_etc_files(system_crond_t)
files_read_etc_runtime_files(system_crond_t)
files_list_all_dirs(system_crond_t)
files_getattr_all_files(system_crond_t)
files_read_usr_files(system_crond_t)
files_read_var_files(system_crond_t)
# for nscd:
files_dontaudit_search_pids(system_crond_t)
# Access other spool directories like
# /var/spool/anacron and /var/spool/slrnpull.
files_manage_generic_spools(system_crond_t)

init_use_fd(system_crond_t)
init_use_script_fd(system_crond_t)
init_use_script_pty(system_crond_t)
init_read_script_pid(system_crond_t)
init_dontaudit_rw_script_pid(system_crond_t)
# prelink tells init to restart it self, we either need to allow or dontaudit
init_write_initctl(system_crond_t)

libs_use_ld_so(system_crond_t)
libs_use_shared_libs(system_crond_t)
libs_exec_lib_files(system_crond_t)
libs_exec_ld_so(system_crond_t)

logging_read_generic_logs(system_crond_t)
logging_send_syslog_msg(system_crond_t)

miscfiles_read_localization(system_crond_t)
miscfiles_read_man_pages(system_crond_t)
miscfiles_rw_man_cache(system_crond_t)

seutil_read_config(system_crond_t)

ifdef(`distro_redhat', `
	# Run the rpm program in the rpm_t domain. Allow creation of RPM log files
	# via redirection of standard out.
	optional_policy(`rpm.te', `
		rpm_manage_log(system_crond_t)
	')
')

tunable_policy(`cron_can_relabel',`
	seutil_domtrans_setfiles(system_crond_t)
',`
	selinux_get_fs_mount(system_crond_t)
	selinux_validate_context(system_crond_t)
	selinux_compute_access_vector(system_crond_t)
	selinux_compute_create_context(system_crond_t)
	selinux_compute_relabel_context(system_crond_t)
	selinux_compute_user_contexts(system_crond_t)
	seutil_read_file_contexts(system_crond_t)
')

optional_policy(`nis.te',`
	nis_use_ypbind(system_crond_t)
')

optional_policy(`nscd.te',`
	nscd_use_socket(system_crond_t)
')

ifdef(`TODO',`
dontaudit userdomain system_crond_t:fd use;

# quiet other ps operations
dontaudit system_crond_t domain:dir { getattr search };

# Do not audit attempts to search unlabeled directories (e.g. slocate).
dontaudit system_crond_t unlabeled_t:dir r_dir_perms;
dontaudit system_crond_t unlabeled_t:file r_file_perms;

allow system_crond_t { sysfs_t rpc_pipefs_t }:dir getattr;

# Write to /var/lib/slocate.db.
allow system_crond_t var_lib_t:dir rw_dir_perms;
allow system_crond_t var_lib_t:file create_file_perms;

# for if /var/mail is a symlink
allow system_crond_t mail_spool_t:lnk_file read;

#
#  These rules are here to allow system cron jobs to su
#
ifdef(`su.te', `
su_restricted_domain(system_crond,system)
role system_r types system_crond_su_t;
allow system_crond_su_t crond_t:fifo_file ioctl;
')

#
# Required for webalizer
#
ifdef(`apache.te', `
allow system_crond_t httpd_log_t:file r_file_perms;
')

ifdef(`mta.te', `
mta_send_mail_transition(system_crond_t)

# system_mail_t should only be reading from the cron fifo not needing to write
dontaudit system_mail_t crond_t:fifo_file write;
allow mta_user_agent system_crond_t:fd use;
r_dir_file(system_mail_t, crond_tmp_t)
')

# for daemon re-start
allow system_crond_t syslogd_t:lnk_file read;

') dnl end TODO