selinux rules for apk files installed with Incremental

Apk files installed with Incremental are actually stored under the
/data/incremental directory.

Since files under /data/incremental are labeled as apk_file_data, we
need additional permissions to enable an apk installation.

Denial messages:

=== vold ===
02-04 14:22:45.756   599   599 I Binder:599_3: type=1400 audit(0.0:607): avc: denied { read } for name="mount" dev="dm-5" ino=894 scontext=u:r:vold:s0 tcontext=u:object_r:apk_data_file:s0 tclass=dir permissive=1
02-04 14:22:45.756   599   599 I Binder:599_3: type=1400 audit(0.0:608): avc: denied { open } for path="/data/incremental/data_incremental_tmp_792314038/mount" dev="dm-5" ino=894 scontext=u:r:vold:s0 tcontext=u:object_r:apk_data_file:s0 tclass=dir permissive=1
02-04 14:22:45.760   599   599 I Binder:599_3: type=1400 audit(0.0:609): avc: denied { mounton } for path="/data/incremental/data_incremental_tmp_792314038/mount" dev="dm-5" ino=894 scontext=u:r:vold:s0 tcontext=u:object_r:apk_data_file:s0 tclass=dir permissive=1
02-04 14:22:45.766  1431  1431 I PackageInstalle: type=1400 audit(0.0:620): avc: denied { read write open } for path="/data/incremental/data_incremental_tmp_792314038/backing_store/.index/f5c14952f6dde3b4a77a94e45388c012" dev="dm-5" ino=897 scontext=u:r:vold:s0
02-04 14:22:45.923  1431  1431 I PackageManager: type=1400 audit(0.0:637): avc: denied { write } for path="/data/incremental/data_incremental_tmp_792314038/backing_store/st_5_0" dev="dm-5" ino=896 scontext=u:r:vold:s0 tcontext=u:object_r:apk_data_file:s0 tclass=dir permissive=1
02-04 14:22:47.326  8839  8839 I android.vending: type=1400 audit(0.0:658): avc: denied { read write open } for path="/data/incremental/data_incremental_tmp_792314038/backing_store/st_6_1/flipboard.app-KPIT2MBSpQYWG-USITOftw==/base.apk" dev="dm-5" ino=899 scontext=u:r:vold:s0 tcontext=u:object_r:apk_data_file:s0 tclass=file permissive=1 app=com.android.vending
02-04 14:22:45.780   599   599 I Binder:599_3: type=1400 audit(0.0:623): avc: denied { getattr } for path="/data/app/vmdl1155417082.tmp" dev="dm-5" ino=888 scontext=u:r:vold:s0 tcontext=u:object_r:apk_tmp_file:s0 tclass=dir permissive=1
02-04 14:22:45.780   599   599 I Binder:599_3: type=1400 audit(0.0:624): avc: denied { read } for name="vmdl1155417082.tmp" dev="dm-5" ino=888 scontext=u:r:vold:s0 tcontext=u:object_r:apk_tmp_file:s0 tclass=dir permissive=1
02-04 14:22:45.780   599   599 I Binder:599_3: type=1400 audit(0.0:625): avc: denied { open } for path="/data/app/vmdl1155417082.tmp" dev="dm-5" ino=888 scontext=u:r:vold:s0 tcontext=u:object_r:apk_tmp_file:s0 tclass=dir permissive=1
02-04 14:22:45.780   599   599 I Binder:599_3: type=1400 audit(0.0:627): avc: denied { mounton } for path="/data/app/vmdl1155417082.tmp" dev="dm-5" ino=888 scontext=u:r:vold:s0 tcontext=u:object_r:apk_tmp_file:s0 tclass=dir permissive=1

02-04 15:32:02.386   591   591 I Binder:591_4: type=1400 audit(0.0:537): avc: denied { search } for name="incremental" dev="dm-5" ino=120 scontext=u:r:vold:s0 tcontext=u:object_r:apk_data_file:s0 tclass=dir permissive=1

=== system_app ===
02-04 14:22:45.793  5064  5064 I Binder:5064_1: type=1400 audit(0.0:633): avc: denied { write } for path="/data/incremental/data_incremental_tmp_792314038/backing_store/st_5_0/base.apk" dev="dm-5" ino=899 scontext=u:r:system_app:s0 tcontext=u:object_r:apk_data_file:s0 tclass=file permissive=1

Test: manual
BUG: 133435829
Change-Id: I70f25a6e63dd2be87ccbe9fb9e9d50fa64d88c36
diff --git a/private/system_app.te b/private/system_app.te
index e5d7d18..1432017 100644
--- a/private/system_app.te
+++ b/private/system_app.te
@@ -69,6 +69,9 @@
 # Settings need to access app name and icon from asec
 allow system_app asec_apk_file:file r_file_perms;
 
+# Allow system_app (adb data loader) to write data to /data/incremental
+allow system_app apk_data_file:file write;
+
 # Allow system apps (like Settings) to interact with statsd
 binder_call(system_app, statsd)