sepolicy: fix support for lmkd

Allow lmkd to access /dev/memcg once again.

Test: lmkd can access memcg
bug 36588803

Change-Id: I47b4e79260bcd2967d85d8151c83e624d432f409
diff --git a/private/file_contexts b/private/file_contexts
index c17a39d..678a705 100644
--- a/private/file_contexts
+++ b/private/file_contexts
@@ -78,6 +78,7 @@
 /dev/cam		u:object_r:camera_device:s0
 /dev/console		u:object_r:console_device:s0
 /dev/cpuctl(/.*)?	u:object_r:cpuctl_device:s0
+/dev/memcg(/.*)?        u:object_r:memcg_device:s0
 /dev/device-mapper	u:object_r:dm_device:s0
 /dev/eac		u:object_r:audio_device:s0
 /dev/event-log-tags     u:object_r:runtime_event_log_tags_file:s0
diff --git a/public/device.te b/public/device.te
index 4a3bec9..15799b8 100644
--- a/public/device.te
+++ b/public/device.te
@@ -21,6 +21,7 @@
 type vold_device, dev_type;
 type console_device, dev_type;
 type cpuctl_device, dev_type;
+type memcg_device, dev_type;
 type fscklogs, dev_type;
 type full_device, dev_type;
 # GPU (used by most UI apps)
diff --git a/public/domain.te b/public/domain.te
index ea63d1c..6b59d6a 100644
--- a/public/domain.te
+++ b/public/domain.te
@@ -226,6 +226,10 @@
 ### neverallow rules
 ###
 
+# Don't allow others to access memcg.
+neverallow { domain -init -lmkd -shell -ueventd } memcg_device:dir *;
+neverallow { domain -init -lmkd -ueventd } memcg_device:file *;
+
 # All socket ioctls must be restricted to a whitelist.
 neverallowxperm domain domain:socket_class_set ioctl { 0 };
 
diff --git a/public/init.te b/public/init.te
index b21c4d0..cf9488f 100644
--- a/public/init.te
+++ b/public/init.te
@@ -77,6 +77,7 @@
 allow init cgroup:dir create_dir_perms;
 r_dir_file(init, cgroup)
 allow init cpuctl_device:dir { create mounton };
+allow init memcg_device:dir { create mounton };
 
 # /config
 allow init configfs:dir mounton;
diff --git a/public/lmkd.te b/public/lmkd.te
index f4e6c2d..c2dcadd 100644
--- a/public/lmkd.te
+++ b/public/lmkd.te
@@ -21,6 +21,9 @@
 r_dir_file(lmkd, sysfs_type)
 allow lmkd sysfs_lowmemorykiller:file w_file_perms;
 
+allow lmkd memcg_device:dir search;
+allow lmkd memcg_device:file rw_file_perms;
+
 # Send kill signals
 allow lmkd appdomain:process sigkill;
 
@@ -32,6 +35,8 @@
 
 allow lmkd proc_zoneinfo:file r_file_perms;
 
+r_dir_file(lmkd, cgroup)
+
 ### neverallow rules
 
 # never honor LD_PRELOAD