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

policy_module(mta,1.0)

########################################
#
# Declarations
#

type etc_aliases_t;
files_type(etc_aliases_t)

type etc_mail_t;
files_type(etc_mail_t)

attribute mailserver_domain;

type mqueue_spool_t;
files_type(mqueue_spool_t)

type mail_spool_t;
files_type(mail_spool_t)

type sendmail_exec_t;
files_type(sendmail_exec_t)

type system_mail_t; #, user_mail_domain
domain_type(system_mail_t)
role system_r types system_mail_t;

ifdef(`targeted_policy',`',`
	optional_policy(`sendmail.te',`
		domain_entry_file(system_mail_t,sendmail_exec_t)
	',`
		init_system_domain(system_mail_t,sendmail_exec_t)
	')
')

########################################
#
# System mail local policy
#

allow system_mail_t self:capability { setuid setgid chown };
allow system_mail_t self:process { signal_perms setrlimit };

allow system_mail_t self:tcp_socket create_socket_perms;

# re-exec itself
can_exec(system_mail_t, sendmail_exec_t)
allow system_mail_t sendmail_exec_t:lnk_file r_file_perms;

kernel_read_kernel_sysctl(system_mail_t)
kernel_read_system_state(system_mail_t)
kernel_read_network_state(system_mail_t)

corenet_tcp_sendrecv_all_if(system_mail_t)
corenet_raw_sendrecv_all_if(system_mail_t)
corenet_tcp_sendrecv_all_nodes(system_mail_t)
corenet_raw_sendrecv_all_nodes(system_mail_t)
corenet_tcp_bind_all_nodes(system_mail_t)
corenet_tcp_sendrecv_all_ports(system_mail_t)

dev_read_urand(system_mail_t)

fs_getattr_xattr_fs(system_mail_t)

init_use_script_pty(system_mail_t)

files_read_etc_runtime_files(system_mail_t)
files_read_etc_files(system_mail_t)
# It wants to check for nscd
files_dontaudit_search_pids(system_mail_t)

corecmd_exec_bin(system_mail_t)

libs_use_ld_so(system_mail_t)
libs_use_shared_libs(system_mail_t)

logging_send_syslog_msg(system_mail_t)

miscfiles_read_localization(system_mail_t)

sysnet_read_config(system_mail_t)

tunable_policy(`use_dns',`
	allow system_mail_t self:udp_socket create_socket_perms;
	corenet_udp_sendrecv_all_if(system_mail_t)
	corenet_udp_sendrecv_all_nodes(system_mail_t)
	corenet_udp_bind_all_nodes(system_mail_t)
	corenet_udp_sendrecv_dns_port(system_mail_t)
')

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

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

optional_policy(`procmail.te',`
	procmail_exec(system_mail_t)
')

ifdef(`TODO',`

optional_policy(`sendmail.te',`
	allow system_mail_t etc_mail_t:dir { getattr search };

	kernel_read_system_state(system_mail_t)

	fs_getattr_xattr_fs(system_mail_t)

	files_read_etc_runtime_files(system_mail_t)

	dontaudit system_mail_t proc_net_t:dir search;

	allow system_mail_t var_t:dir getattr;
	allow system_mail_t var_spool_t:dir getattr;
	dontaudit system_mail_t userpty_type:chr_file { getattr read write };

	# sendmail -q 
	allow system_mail_t mqueue_spool_t:dir rw_dir_perms;
	allow system_mail_t mqueue_spool_t:file create_file_perms;

	optional_policy(`crond.te', `
		dontaudit system_mail_t system_crond_tmp_t:file append;
	')
')

allow system_mail_t device_t:dir search;
allow system_mail_t { var_t var_spool_t }:dir search;
allow system_mail_t sbin_t:dir search;

# Transition from a system domain to the derived domain.
domain_auto_trans(privmail, sendmail_exec_t, system_mail_t)
allow privmail sendmail_exec_t:lnk_file { getattr read };

optional_policy(`crond.te',`
	# Read cron temporary files.
	allow system_mail_t system_crond_tmp_t:file r_file_perms;
	allow mta_user_agent system_crond_tmp_t:file r_file_perms;
')

ifdef(`qmail.te', `
	allow system_mail_t qmail_etc_t:dir search;
	allow system_mail_t qmail_etc_t:{ file lnk_file } read;
')

ifdef(`targeted_policy', `
	allow system_mail_t { var_t var_spool_t }:dir getattr;

	allow system_mail_t etc_mail_t:file r_file_perms;

	allow system_mail_t mail_spool_t:dir create_dir_perms;
	allow system_mail_t mail_spool_t:file create_file_perms;
	allow system_mail_t mail_spool_t:lnk_file create_lnk_perms;
	allow system_mail_t mail_spool_t:fifo_file rw_file_perms;

	allow system_mail_t mqueue_spool_t:dir create_dir_perms;
	allow system_mail_t mqueue_spool_t:file create_file_perms;
	allow system_mail_t mqueue_spool_t:lnk_file create_lnk_perms;

	optional_policy(`postfix.te',`',`
		corecmd_exec_bin(system_mail_t)
		corecmd_exec_sbin(system_mail_t)

		domain_exec_all_entry_files(system_mail_t)

		files_exec_etc_files(system_mail_t)

		libs_use_ld_so(system_mail_t)
		libs_use_shared_libs(system_mail_t)
		libs_exec_ld_so(system_mail_t)
		libs_exec_lib_files(system_mail_t)
	')
',`
	optional_policy(`sendmail.te', `
		# sendmail has an ugly design, the one process parses input from the user and
		# then does system things with it.
		domain_auto_trans(initrc_t, sendmail_exec_t, sendmail_t)
	')

	# allow the sysadmin to do "mail someone < /home/user/whatever"
	allow sysadm_mail_t user_home_dir_type:dir search;
	r_dir_file(sysadm_mail_t, user_home_type)
')

# for a mail server process that does things in response to a user command
allow mta_user_agent userdomain:process sigchld;
allow mta_user_agent { userdomain privfd }:fd use;
ifdef(`crond.te', `
allow mta_user_agent crond_t:process sigchld;
')
allow mta_user_agent sysadm_t:fifo_file { read write };

allow { system_mail_t mta_user_agent } privmail:fd use;
allow { system_mail_t mta_user_agent } privmail:process sigchld;
allow { system_mail_t mta_user_agent } privmail:fifo_file { read write };
allow { system_mail_t mta_user_agent } admin_tty_type:chr_file { read write };

ifdef(`arpwatch.te', `
# why is mail delivered to a directory of type arpwatch_data_t?
allow mta_delivery_agent arpwatch_data_t:dir search;
allow { system_mail_t mta_user_agent } arpwatch_tmp_t:file rw_file_perms;
ifdef(`hide_broken_symptoms', `
dontaudit { system_mail_t mta_user_agent } arpwatch_t:packet_socket { read write };
')
')dnl end if arpwatch.te

allow mta_delivery_agent home_root_t:dir { getattr search };

# for /var/spool/mail
ra_dir_create_file(mta_delivery_agent, mail_spool_t)

# for piping mail to a command
can_exec(mta_delivery_agent, shell_exec_t)
allow mta_delivery_agent bin_t:dir search;
allow mta_delivery_agent bin_t:lnk_file read;
allow mta_delivery_agent { etc_runtime_t proc_t }:file r_file_perms;

# Transition from a system domain to the derived domain.
domain_auto_trans(privmail, sendmail_exec_t, system_mail_t)
allow privmail sendmail_exec_t:lnk_file r_file_perms;

ifdef(`crond.te', `
# Read cron temporary files.
allow system_mail_t system_crond_tmp_t:file r_file_perms;
allow mta_user_agent system_crond_tmp_t:file r_file_perms;
')

optional_policy(`logrotate.te', `
	allow { system_mail_t mta_user_agent } logrotate_tmp_t:file r_file_perms;
')

') dnl end TODO