MediaTranscodingService: Add sepolicy for MediaTranscodingService.

Bug:145233472
Test: Build and flash the phone.
"adb shell dumpsys -l | grep media" shows media.transcoding service.

Change-Id: I48a42e7b595754989c92a8469eb91360ab6db7c6

private/compat/29.0/29.0.ignore.cil

@@ -26,6 +26,10 @@
     iorap_prefetcherd_data_file
     iorap_prefetcherd_exec
     iorap_prefetcherd_tmpfs
+    mediatranscoding_service
+    mediatranscoding
+    mediatranscoding_exec
+    mediatranscoding_tmpfs
     linker_prop
     mock_ota_prop
     ota_metadata_file

private/file_contexts

@@ -239,6 +239,7 @@
 /system/bin/cameraserver	u:object_r:cameraserver_exec:s0
 /system/bin/mediaextractor	u:object_r:mediaextractor_exec:s0
 /system/bin/mediaswcodec	u:object_r:mediaswcodec_exec:s0
+/system/bin/mediatranscoding	u:object_r:mediatranscoding_exec:s0
 /system/bin/mdnsd	u:object_r:mdnsd_exec:s0
 /system/bin/installd	u:object_r:installd_exec:s0
 /system/bin/otapreopt_chroot   u:object_r:otapreopt_chroot_exec:s0

private/mediaserver.te

@@ -10,3 +10,4 @@ hal_client_domain(mediaserver, hal_drm)
 hal_client_domain(mediaserver, hal_omx)
 hal_client_domain(mediaserver, hal_codec2)
 
+allow mediaserver mediatranscoding_service:service_manager find;

private/mediatranscoding.te

@@ -0,0 +1,3 @@
+typeattribute mediatranscoding coredomain;
+
+init_daemon_domain(mediatranscoding)

private/service_contexts

@@ -118,6 +118,7 @@ media.log                                 u:object_r:audioserver_service:s0
 media.player                              u:object_r:mediaserver_service:s0
 media.metrics                             u:object_r:mediametrics_service:s0
 media.extractor                           u:object_r:mediaextractor_service:s0
+media.transcoding                         u:object_r:mediatranscoding_service:s0
 media.resource_manager                    u:object_r:mediaserver_service:s0
 media.sound_trigger_hw                    u:object_r:audioserver_service:s0
 media.drm                                 u:object_r:mediadrmserver_service:s0

public/mediatranscoding.te

@@ -0,0 +1,26 @@
+# mediatranscoding - daemon for transcoding video and image.
+type mediatranscoding, domain;
+type mediatranscoding_exec, system_file_type, exec_type, file_type;
+
+binder_use(mediatranscoding)
+binder_service(mediatranscoding)
+
+add_service(mediatranscoding, mediatranscoding_service)
+
+allow mediatranscoding system_server:fd use;
+
+# mediatranscoding should never execute any executable without a
+# domain transition
+neverallow mediatranscoding { file_type fs_type }:file execute_no_trans;
+
+# The goal of the mediaserver split is to place media processing code into
+# restrictive sandboxes with limited responsibilities and thus limited
+# permissions. Example: Audioserver is only responsible for controlling audio
+# hardware and processing audio content. Cameraserver does the same for camera
+# hardware/content. Etc.
+#
+# Media processing code is inherently risky and thus should have limited
+# permissions and be isolated from the rest of the system and network.
+# Lengthier explanation here:
+# https://android-developers.googleblog.com/2016/05/hardening-media-stack.html
+neverallow mediatranscoding domain:{ tcp_socket udp_socket rawip_socket } *;

public/service.te

@@ -21,6 +21,7 @@ type mediaserver_service,       service_manager_type;
 type mediametrics_service,      service_manager_type;
 type mediaextractor_service,    service_manager_type;
 type mediadrmserver_service,    service_manager_type;
+type mediatranscoding_service,  app_api_service, service_manager_type;
 type netd_service,              service_manager_type;
 type nfc_service,               service_manager_type;
 type radio_service,             service_manager_type;