system/core commit 331cf2fb7c16b5b25064f8d2f00284105a9b413f created a
number of new properties of the form:

  [ro.boottime.init]: [5294587604]
  [ro.boottime.InputEventFind]: [10278767840]
  [ro.boottime.adbd]: [8359267180]
  ...

These properties were assigned the default_prop SELinux label because a
better label did not exist. Properties labeled with the default_prop
label are readable to any SELinux domain, which is overly broad.

  bullhead:/ $ getprop -Z ro.boottime.adbd
  u:object_r:default_prop:s0

Instead, create a new label for the ro.boottime.* properties so we can
apply more fine grain read access control to these properties.

  bullhead:/ $ getprop -Z ro.boottime.adbd
  u:object_r:boottime_prop:s0

New SELinux property labels have minimal permissions by default. As a
result, after this change, ro.boottime.* properties will only be
readable to system_server, bootstat, init (because it manages the property
space), and "adb root" (because no SELinux permissions are enforced there).

Additional read access can be granted as-needed.

This is part of a larger effort to implement fine-grain access control
on the properties managed by init.

Test: Device boots and no SELinux denials on boot.
Change-Id: Ibf981cb81898f4356fdc5c1b6f15dd93c0d6d84d

Because I'm nitpicky.

Test: policy compiles
Change-Id: I4d886d0d6182d29d7b260cf1f142c47cd32eda29

Divide policy into public and private components.  This is the first
step in splitting the policy creation for platform and non-platform
policies.  The policy in the public directory will be exported for use
in non-platform policy creation.  Backwards compatibility with it will
be achieved by converting the exported policy into attribute-based
policy when included as part of the non-platform policy and a mapping
file will be maintained to be included with the platform policy that
maps exported attributes of previous versions to the current platform
version.

Eventually we would like to create a clear interface between the
platform and non-platform device components so that the exported policy,
and the need for attributes is minimal.  For now, almost all types and
avrules are left in public.

Test: Tested by building policy and running on device.

Change-Id: Idef796c9ec169259787c3f9d8f423edf4ce27f8c

* Allow reading /proc.

type=1400 audit(1453834004.239:7): avc: denied { read } for pid=1305
comm="bootstat" name="uptime" dev="proc" ino=4026536600
scontext=u:r:bootstat:s0 tcontext=u:object_r:proc:s0 tclass=file
permissive=0

* Define domain for the /system/bin/bootstat file.

init: Service exec 4 (/system/bin/bootstat) does not have a SELinux
domain defined.

Bug: 21724738
Change-Id: I4baa2fa7466ac35a1ced79776943c07635ec9804

/data/misc/bootstat.

BUG: 21724738
Change-Id: I2789f57cc8182af1a7c33672ef82297f32f54e2e