selinux-policy/refpolicy/policy/modules/admin/su.if

## <summary>Run shells with substitute user and group</summary>

#######################################
## <summary>
##	Restricted su domain template.
## </summary>
## <desc>
##	<p>
##	This template creates a derived domain which is allowed
##	to change the linux user id, to run shells as a different
##	user.
##	</p>
## </desc>
## <param name="userdomain_prefix">
##	<summary>
##	The prefix of the user domain (e.g., user
##	is the prefix for user_t).
##	</summary>
## </param>
## <param name="user_domain">
##	<summary>
##	The type of the user domain.
##	</summary>
## </param>
## <param name="user_role">
##	<summary>
##	The role associated with the user domain.
##	</summary>
## </param>
#
template(`su_restricted_domain_template', `
	gen_require(`
		type su_exec_t;
	')

	type $1_su_t;
	domain_entry_file($1_su_t,su_exec_t)
	domain_type($1_su_t)
	domain_interactive_fd($1_su_t)
	role $3 types $1_su_t;

	allow $2 $1_su_t:process signal;

	allow $1_su_t self:capability { audit_control audit_write setuid setgid net_bind_service chown dac_override fowner sys_nice sys_resource };
	dontaudit $1_su_t self:capability sys_tty_config;
	allow $1_su_t self:process { setexec setsched setrlimit };
	allow $1_su_t self:fifo_file rw_file_perms;
	allow $1_su_t self:netlink_audit_socket { nlmsg_relay create_netlink_socket_perms };
	allow $1_su_t self:unix_stream_socket create_stream_socket_perms;

	# Transition from the user domain to this domain.
	domain_auto_trans($2, su_exec_t, $1_su_t)
	allow $1_su_t $2:fd use;
	allow $1_su_t $2:fifo_file rw_file_perms;
	allow $1_su_t $2:process sigchld;

	# By default, revert to the calling domain when a shell is executed.
	corecmd_shell_domtrans($1_su_t,$2)
	allow $2 $1_su_t:fd use;
	allow $2 $1_su_t:fifo_file rw_file_perms;
	allow $2 $1_su_t:process sigchld;

	kernel_read_system_state($1_su_t)
	kernel_read_kernel_sysctls($1_su_t)

	# for SSP
	dev_read_urand($1_su_t)

	files_read_etc_files($1_su_t)
	files_read_etc_runtime_files($1_su_t)
	files_search_var_lib($1_su_t)
	files_dontaudit_getattr_tmp_dirs($1_su_t)

	auth_domtrans_chk_passwd($1_su_t)
	auth_dontaudit_read_shadow($1_su_t)
	auth_use_nsswitch($1_su_t)

	domain_use_interactive_fds($1_su_t)

	init_dontaudit_use_fds($1_su_t)
	init_dontaudit_use_script_ptys($1_su_t)
	# Write to utmp.
	init_rw_utmp($1_su_t)

	libs_use_ld_so($1_su_t)
	libs_use_shared_libs($1_su_t)

	logging_send_syslog_msg($1_su_t)

	miscfiles_read_localization($1_su_t)

	ifdef(`distro_rhel4',`
		domain_role_change_exemption($1_su_t)
		domain_subj_id_change_exemption($1_su_t)
		domain_obj_id_change_exemption($1_su_t)

		selinux_get_fs_mount($1_su_t)
		selinux_validate_context($1_su_t)
		selinux_compute_access_vector($1_su_t)
		selinux_compute_create_context($1_su_t)
		selinux_compute_relabel_context($1_su_t)
		selinux_compute_user_contexts($1_su_t)

		seutil_read_config($1_su_t)
		seutil_read_default_contexts($1_su_t)

		# Only allow transitions to unprivileged user domains.
		userdom_spec_domtrans_unpriv_users($1_su_t)
	')

	optional_policy(`
		cron_read_pipes($1_su_t)
	')

	optional_policy(`
		kerberos_use($1_su_t)
	')

	optional_policy(`
		nscd_socket_use($1_su_t)
	')

	ifdef(`TODO',`
	# Caused by su - init scripts
	dontaudit $1_su_t initrc_devpts_t:chr_file { getattr ioctl };
	') dnl end TODO
')

#######################################
## <summary>
##	The per user domain template for the su module.
## </summary>
## <desc>
##	<p>
##	This template creates a derived domain which is allowed
##	to change the linux user id, to run shells as a different
##	user.
##	</p>
##	<p>
##	This template is invoked automatically for each user, and
##	generally does not need to be invoked directly
##	by policy writers.
##	</p>
## </desc>
## <param name="userdomain_prefix">
##	<summary>
##	The prefix of the user domain (e.g., user
##	is the prefix for user_t).
##	</summary>
## </param>
## <param name="user_domain">
##	<summary>
##	The type of the user domain.
##	</summary>
## </param>
## <param name="user_role">
##	<summary>
##	The role associated with the user domain.
##	</summary>
## </param>
#
template(`su_per_userdomain_template',`
	gen_require(`
		type su_exec_t;
		bool secure_mode;
	')

	type $1_su_t;
	domain_entry_file($1_su_t,su_exec_t)
	domain_type($1_su_t)
	domain_interactive_fd($1_su_t)
	role $3 types $1_su_t;

	allow $2 $1_su_t:process signal;

	allow $1_su_t self:capability { audit_control audit_write setuid setgid net_bind_service chown dac_override fowner sys_nice sys_resource };
	dontaudit $1_su_t self:capability sys_tty_config;
	allow $1_su_t self:process { setexec setsched setrlimit };
	allow $1_su_t self:fifo_file rw_file_perms;
	allow $1_su_t self:netlink_audit_socket { nlmsg_relay create_netlink_socket_perms };

	# Transition from the user domain to this domain.
	domain_auto_trans($2, su_exec_t, $1_su_t)
	allow $1_su_t $2:fd use;
	allow $1_su_t $2:fifo_file rw_file_perms;
	allow $1_su_t $2:process sigchld;

	# By default, revert to the calling domain when a shell is executed.
	corecmd_shell_domtrans($1_su_t,$2)
	allow $2 $1_su_t:fd use;
	allow $2 $1_su_t:fifo_file rw_file_perms;
	allow $2 $1_su_t:process sigchld;

	kernel_read_system_state($1_su_t)
	kernel_read_kernel_sysctls($1_su_t)

	# for SSP
	dev_read_urand($1_su_t)

	fs_search_auto_mountpoints($1_su_t)

	auth_domtrans_user_chk_passwd($1,$1_su_t)
	auth_dontaudit_read_shadow($1_su_t)
	auth_use_nsswitch($1_su_t)

	corecmd_search_bin($1_su_t)
	corecmd_search_sbin($1_su_t)

	domain_use_interactive_fds($1_su_t)

	files_read_etc_files($1_su_t)
	files_read_etc_runtime_files($1_su_t)
	files_search_var_lib($1_su_t)
	files_dontaudit_getattr_tmp_dirs($1_su_t)

	init_dontaudit_use_fds($1_su_t)
	# Write to utmp.
	init_rw_utmp($1_su_t)

	libs_use_ld_so($1_su_t)
	libs_use_shared_libs($1_su_t)

	logging_send_syslog_msg($1_su_t)

	miscfiles_read_localization($1_su_t)

	userdom_use_user_terminals($1,$1_su_t)
	userdom_search_user_home_dirs($1,$1_su_t)

	ifdef(`distro_rhel4',`
		domain_role_change_exemption($1_su_t)
		domain_subj_id_change_exemption($1_su_t)
		domain_obj_id_change_exemption($1_su_t)

		selinux_get_fs_mount($1_su_t)
		selinux_validate_context($1_su_t)
		selinux_compute_access_vector($1_su_t)
		selinux_compute_create_context($1_su_t)
		selinux_compute_relabel_context($1_su_t)
		selinux_compute_user_contexts($1_su_t)

		# Relabel ttys and ptys.
		term_relabel_all_user_ttys($1_su_t)
		term_relabel_all_user_ptys($1_su_t)
		# Close and re-open ttys and ptys to get the fd into the correct domain.
		term_use_all_user_ttys($1_su_t)
		term_use_all_user_ptys($1_su_t)

		seutil_read_config($1_su_t)
		seutil_read_default_contexts($1_su_t)

		ifdef(`strict_policy',`
			if(secure_mode) {
				# Only allow transitions to unprivileged user domains.
				userdom_spec_domtrans_unpriv_users($1_su_t)
			} else {
				# Allow transitions to all user domains
				userdom_spec_domtrans_all_users($1_su_t)
			}
		')

		ifdef(`targeted_policy',`
			unconfined_domtrans($1_su_t)
			unconfined_signal($1_su_t)
		')
	')

	ifdef(`enable_polyinstantiation',`
		fs_mount_xattr_fs($1_su_t)
		fs_unmount_xattr_fs($1_su_t)
	')

	ifdef(`targeted_policy',`
		# allow user to suspend terminal.
		# does not work in strict since the
		# parent may not be able to use
		# the terminal if we newrole,
		# which relabels the terminal.
		allow $1_su_t self:process sigstop;

		corecmd_exec_bin($1_su_t)
		userdom_manage_all_users_home_content_files($1_su_t)
		userdom_manage_all_users_home_content_symlinks($1_su_t)
	')

	tunable_policy(`use_nfs_home_dirs',`
		fs_search_nfs($1_su_t)
	')

	tunable_policy(`use_samba_home_dirs',`
		fs_search_cifs($1_su_t)
	')

	optional_policy(`
		cron_read_pipes($1_su_t)
	')

	optional_policy(`
		kerberos_use($1_su_t)
	')

	optional_policy(`
		nscd_socket_use($1_su_t)
	')

	# Modify .Xauthority file (via xauth program).
	optional_policy(`
#		file_type_auto_trans($1_su_t, staff_home_dir_t, staff_xauth_home_t, file)
#		file_type_auto_trans($1_su_t, user_home_dir_t, user_xauth_home_t, file)
#		file_type_auto_trans($1_su_t, sysadm_home_dir_t, sysadm_xauth_home_t, file)
		xserver_domtrans_user_xauth($1, $1_su_t)
	')

	ifdef(`TODO',`
	allow $1_su_t $1_home_t:file create_file_perms;

	ifdef(`ssh.te', `
	# Access sshd cookie files.
	allow $1_su_t sshd_tmp_t:file rw_file_perms;
	file_type_auto_trans($1_su_t, sshd_tmp_t, $1_tmp_t)
	')
	') dnl end TODO
')

#######################################
## <summary>
##	Execute su in the caller domain.
## </summary>
## <param name="domain">
##	<summary>
##	Domain allowed access.
##	</summary>
## </param>
#
interface(`su_exec',`
	gen_require(`
		type su_exec_t;
	')

	can_exec($1,su_exec_t)
')