platform_system_sepolicy/init.te

# init switches to init domain (via init.rc).
type init, domain;
# init is unconfined.
unconfined_domain(init)
tmpfs_domain(init)

allow init self:capability { sys_rawio mknod };

# Mounting filesystems from block devices.
allow init dev_type:blk_file r_file_perms;

# Mounting filesystems.
# Only allow relabelto for types used in context= mount options,
# which should all be assigned the contextmount_type attribute.
# This can be done in device-specific policy via type or typeattribute
# declarations.
allow init fs_type:filesystem ~relabelto;
allow init unlabeled:filesystem ~relabelto;
allow init contextmount_type:filesystem relabelto;

# Allow read-only access to context= mounted filesystems.
allow init contextmount_type:dir r_dir_perms;
allow init contextmount_type:notdevfile_class_set r_file_perms;

# restorecon /adb_keys or any other rootfs files to a more specific type.
allow init rootfs:file relabelfrom;

# restorecon and restorecon_recursive calls from init.rc files.
# system/core/init.rc requires at least cache_file and data_file_type.
# init.<board>.rc files often include device-specific types, so
# we just allow all file types except /system files here.
allow init {file_type -system_file -exec_type}:dir_file_class_set relabelto;
allow init sysfs_type:{ dir file lnk_file } relabelto;

# Unlabeled file access for upgrades from 4.2.
allow init unlabeled:dir { create_dir_perms relabelfrom };
allow init unlabeled:notdevfile_class_set { create_file_perms relabelfrom };

# Create /data/security from init.rc post-fs-data.
allow init security_file:dir { create setattr };

# setprop selinux.reload_policy 1 from init.rc post-fs-data.
allow init security_prop:property_service set;

# Reload policy upon setprop selinux.reload_policy 1.
r_dir_file(init, security_file)
allow init kernel:security load_policy;

# Any operation that can modify the kernel ring buffer, e.g. clear
# or a read that consumes the messages that were read.
allow init kernel:system syslog_mod;

# Set usermodehelpers and /proc security settings.
allow init usermodehelper:file rw_file_perms;
allow init proc_security:file rw_file_perms;

# Transitions to seclabel processes in init.rc
domain_trans(init, rootfs, adbd)
domain_trans(init, rootfs, healthd)
recovery_only(`
  domain_trans(init, rootfs, recovery)
')
domain_trans(init, shell_exec, shell)
domain_trans(init, rootfs, ueventd)
domain_trans(init, rootfs, watchdogd)

# Certain domains need LD_PRELOAD passed from init.
# https://android-review.googlesource.com/94851
# For now, allow it to most domains.
# TODO: scope this down.
allow init { domain -lmkd }:process noatsecure;

# Support "adb shell stop"
allow init domain:process sigkill;

# Init creates keystore's directory on boot, and walks through
# the directory as part of a recursive restorecon.
allow init keystore_data_file:dir { open create read getattr setattr search };
allow init keystore_data_file:file { getattr };

# Init creates /data/local/tmp at boot
allow init shell_data_file:dir { open create read getattr setattr search };
allow init shell_data_file:file { getattr };

# Use setexeccon(), setfscreatecon(), and setsockcreatecon().
# setexec is for services with seclabel options.
# setfscreate is for labeling directories and socket files.
# setsockcreate is for labeling local/unix domain sockets.
allow init self:process { setexec setfscreate setsockcreate };

# Create /data/property and files within it.
allow init property_data_file:dir create_dir_perms;
allow init property_data_file:file create_file_perms;

# Set any property.
allow init property_type:property_service set;

# Run "ifup lo" to bring up the localhost interface
allow init self:udp_socket { create ioctl };

# This line seems suspect, as it should not really need to
# set scheduling parameters for a kernel domain task.
allow init kernel:process setsched;

# swapon() needs write access to swap device
# system/core/fs_mgr/fs_mgr.c - fs_mgr_swapon_all
allow init swap_block_device:blk_file rw_file_perms;

# Read from /dev/hw_random if present.
# system/core/init/init.c - mix_hwrng_into_linux_rng_action
allow init hw_random_device:chr_file r_file_perms;

# Create and access /dev files without a specific type,
# e.g. /dev/.coldboot_done.
# TODO:  Move these files into their own type unless they are
# only ever accessed by init.
allow init device:file create_file_perms;
auditallow init device:file create_file_perms;

# Access character devices without a specific type,
# e.g. /dev/keychord.
# TODO: Move these devices into their own type unless they
# are only ever accessed by init.
allow init device:chr_file { rw_file_perms setattr };
auditallow init device:chr_file { rw_file_perms setattr };

###
### neverallow rules
###

# The init domain is only entered via setcon from the kernel domain,
# never via an exec-based transition.
neverallow { domain -kernel} init:process dyntransition;
neverallow domain init:process transition;
neverallow init { file_type fs_type }:file entrypoint;

# Never read/follow symlinks created by shell or untrusted apps.
neverallow init shell_data_file:lnk_file read;
neverallow init app_data_file:lnk_file read;

# init should never execute a program without changing to another domain.
neverallow init { file_type fs_type }:file execute_no_trans;