1# Life begins with the kernel.
2type kernel, domain;
3
4# Run /init before we have switched domains.
5allow kernel rootfs:file execute_no_trans;
6
7# setcon to init domain.
8allow kernel self:process setcurrent;
9allow kernel init:process dyntransition;
10
11# The kernel is unconfined.
12unconfined_domain(kernel)
13
14# cgroup filesystem initialization prior to setting the cgroup root directory label.
15allow kernel unlabeled:dir search;
16
17# Mount usbfs.
18allow kernel usbfs:filesystem mount;
19
20# init direct restorecon calls prior to switching to init domain
21# /dev and /dev/socket
22allow kernel { device socket_device }:dir relabelto;
23# /dev/__properties__
24allow kernel properties_device:file relabelto;
25# /sys
26allow kernel sysfs:{ dir file lnk_file } relabelfrom;
27allow kernel sysfs_type:{ dir file lnk_file } relabelto;
28
29# Initial setenforce by init prior to switching to init domain.
30# We use dontaudit instead of allow to prevent a kernel spawned userspace
31# process from turning off SELinux once enabled.
32dontaudit kernel self:security setenforce;
33
34# Set checkreqprot by init.rc prior to switching to init domain.
35allow kernel self:security setcheckreqprot;
36
37# MTP sync (b/15835289)
38# kernel thread "loop0", used by the loop block device, for ASECs (b/17158723)
39allow kernel sdcard_type:file { read write };
40
41# Allow the kernel to read OBB files from app directories. (b/17428116)
42# Kernel thread "loop0" reads a vold supplied file descriptor.
43# Fixes CTS tests:
44#  * android.os.storage.cts.StorageManagerTest#testMountAndUnmountObbNormal
45#  * android.os.storage.cts.StorageManagerTest#testMountAndUnmountTwoObbs
46allow kernel app_data_file:file read;
47
48###
49### neverallow rules
50###
51
52# The initial task starts in the kernel domain (assigned via
53# initial_sid_contexts), but nothing ever transitions to it.
54neverallow domain kernel:process { transition dyntransition };
55
56# The kernel domain is never entered via an exec, nor should it
57# ever execute a program outside the rootfs without changing to another domain.
58# If you encounter an execute_no_trans denial on the kernel domain, then
59# possible causes include:
60# - The program is a kernel usermodehelper.  In this case, define a domain
61#   for the program and domain_auto_trans() to it.
62# - You failed to setcon u:r:init:s0 in your init.rc and thus your init
63#   program was left in the kernel domain and is now trying to execute
64#   some other program.  Fix your init.rc file.
65# - You are running an exploit which switched to the init task credentials
66#   and is then trying to exec a shell or other program.  You lose!
67neverallow kernel { file_type fs_type -rootfs }:file { entrypoint execute_no_trans };
68