This adds neverallow rules which enforce the prohibition on
communication between framework and vendor components over VendorBinder.
This prohibition is similar in spirit to the one for Binder
communications.

Most changes consist of adding neverallow rules, which do not affect
runtime behavior. The only change which does affect runtime behavior
is the change which takes away the right of servicemanager domain to
transfer Binder tokens to hwservicemanager and vndservicemanager. This
grant was there by accident (because it was overly broad) and is not
expected to be needed: servicemanager, hwservicemanager, and
vndservicemanager are not supposed to be communicating with each
other.

P. S. The new neverallow rules in app_neverallows.te are covered by
the new rules in domain.te. The rules were nevertheless added to
app_neverallows.te for consistency with other *Binder rules there.

Test: mmm system/sepolicy
Bug: 37663632
Change-Id: I7c2ae23924bf0f2fed3f1e3a8d4d603129286329

This adds a neverallow rules which checks that SELinux app domains
which host arbitrary code are not allowed to access hwservicemanager
operations other than "find" operation for which there already are
strict neverallow rules in the policy.

Test: mmm system/sepolicy -- neverallow-only change
Bug: 34454312
Change-Id: I3b80c6ae2c254495704e0409e0c5c88f6ce3a6a7

App domains which host arbitrary code must not have access to
arbitrary HwBinder services. Such access unnecessarily increases the
attack surface. The reason is twofold:
1. HwBinder servers do not perform client authentication because HIDL
   currently does not expose caller UID information and, even if it
   did, many HwBinder services either operate at a layer below that of
   apps (e.g., HALs) or must not rely on app identity for
   authorization. Thus, to be safe, the default assumption is that
   a HwBinder service treats all its clients as equally authorized to
   perform operations offered by the service.
2. HAL servers (a subset of HwBinder services) contain code with
   higher incidence rate of security issues than system/core
   components and have access to lower layes of the stack (all the way
   down to hardware) thus increasing opportunities for bypassing the
   Android security model.

HwBinder services offered by core components (as opposed to vendor
components) are considered safer because of point #2 above.

Always same-process aka always-passthrough HwBinder services are
considered safe for access by these apps. This is because these HALs
by definition do not offer any additional access beyond what its
client already as, because these services run in the process of the
client.

This commit thus introduces these two categories of HwBinder services
in neverallow rules.

Test: mmm system/sepolicy -- this does not change on-device policy
Bug: 34454312
Change-Id: I4f5f4dd10b3fc3bb9d262dda532d4a23dcdf061d

Bug: 37541374
Test: Build and boot sailfish

Change-Id: I8afe9463070cca45b3f1029cc168a3bf00ed7cdc
Signed-off-by: Sandeep Patil <sspatil@google.com>

Prevent app domains (processes spawned by zygote) from acquiring
locks on files in /system. In particular, /system/etc/xtables.lock
must never be lockable by applications, as it will block future
iptables commands from running.

Test: device boots and no obvious problems.
Change-Id: Ifd8dc7b117cf4a622b30fd4fffbcab1b76c4421b

Untrusted apps should only access /data/preloads/media and demo directory.

Bug: 36197686
Test: Verified retail mode.
      Checked non-privileged APK cannot access /data/preloads
Change-Id: I8e9c21ff6aba799aa31bf06893cdf60dafc04446

We simplified the way we track whether or not a dex file is used by
other apps. DexManager in the framework keeps track of the data and we
no longer need file markers on disk.

Test: device boots, foreign dex markers are not created anymore

Bug: 32871170
Change-Id: I464ed6b09439cf0342020ee07596f9aa8ae53b62

untrusted_v2_app is basically a refinement of untrusted_app with legacy
capabilities removed and potentially backwards incompatible changes.

This is not currently hooked up to anything.

Bug: 33350220
Test: builds
Change-Id: Ic9fad57476bc2b6022b1eaca8667bf6d844753c2

Motivation:
Provide the ability to phase in new security policies by
applying them to apps with a minimum targetSdkVersion.

Place untrusted apps with targetSdkVersion<=25 into the
untrustd_app_25 domain. Apps with targetSdkVersion>=26 are placed
into the untrusted_app domain. Common rules are included in the
untrusted_app_all attribute. Apps with a more recent targetSdkVersion
are granted fewer permissions.

Test: Marlin builds and boots. Apps targeting targetSdkVersion<=25
run in untrusted_app_25 domain. Apps targeting the current development
build >=26 run in the untrusted_app domain with fewer permissions. No
new denials observed during testing.
Bug: 34115651
Bug: 35323421
Change-Id: Ie6a015566fac07c44ea06c963c40793fcdc9a083

The implementation for NETLINK_FIREWALL and NETLINK_IP6_FW protocols
was removed from the kernel in commit
d16cf20e2f2f13411eece7f7fb72c17d141c4a84 ("netfilter: remove ip_queue
support") circa Linux 3.5.  Unless we need to retain compatibility
for kernels < 3.5, we can drop these classes from the policy altogether.

Possibly the neverallow rule in app.te should be augmented to include
the newer netlink security classes, similar to webview_zygote, but
that can be a separate change.

Test: policy builds

Change-Id: Iab9389eb59c96772e5fa87c71d0afc86fe99bb6b
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

The neverallows in untrusted_app will all apply equally to ephemeral app
and any other untrusted app domains we may add, so this moves them to a
dedicated separate file.

This also removes the duplicate rules from isolated_app.te and ensures
that all the untrusted_app neverallows also apply to isolated_app.

Test: builds
Change-Id: Ib38e136216ccbe5c94daab732b7ee6acfad25d0b