platform_system_sepolicy/private/audioserver.te

# audioserver - audio services daemon

typeattribute audioserver coredomain;

type audioserver_exec, exec_type, file_type;
init_daemon_domain(audioserver)

r_dir_file(audioserver, sdcard_type)

binder_use(audioserver)
binder_call(audioserver, binderservicedomain)
binder_call(audioserver, appdomain)
binder_service(audioserver)

hal_client_domain(audioserver, hal_allocator)
# /system/lib64/hw for always-passthrough Allocator HAL ashmem / mapper .so
r_dir_file(audioserver, system_file)

hal_client_domain(audioserver, hal_audio)

userdebug_or_eng(`
  # used for TEE sink - pcm capture for debug.
  allow audioserver media_data_file:dir create_dir_perms;
  allow audioserver audioserver_data_file:dir create_dir_perms;
  allow audioserver audioserver_data_file:file create_file_perms;

  # ptrace to processes in the same domain for memory leak detection
  allow audioserver self:process ptrace;
')

add_service(audioserver, audioserver_service)
allow audioserver activity_service:service_manager find;
allow audioserver appops_service:service_manager find;
allow audioserver batterystats_service:service_manager find;
allow audioserver permission_service:service_manager find;
allow audioserver power_service:service_manager find;
allow audioserver scheduling_policy_service:service_manager find;

# Allow read/write access to bluetooth-specific properties
set_prop(audioserver, bluetooth_prop)

# Grant access to audio files to audioserver
allow audioserver audio_data_file:dir ra_dir_perms;
allow audioserver audio_data_file:file create_file_perms;

# allow access to ALSA MMAP FDs for AAudio API
allow audioserver audio_device:chr_file { read write };

not_full_treble(`allow audioserver audio_device:dir r_dir_perms;')
not_full_treble(`allow audioserver audio_device:chr_file rw_file_perms;')

# For A2DP bridge which is loaded directly into audioserver
unix_socket_connect(audioserver, bluetooth, bluetooth)

# Allow shell commands from ADB and shell for CTS testing/dumping
allow audioserver adbd:fd use;
allow audioserver adbd:unix_stream_socket { read write };
allow audioserver shell:fifo_file { read write };

# Allow shell commands from ADB for CTS testing/dumping
userdebug_or_eng(`
  allow audioserver su:fd use;
  allow audioserver su:fifo_file { read write };
  allow audioserver su:unix_stream_socket { read write };
')

###
### neverallow rules
###

# audioserver should never execute any executable without a
# domain transition
neverallow audioserver { 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 audioserver domain:{ tcp_socket udp_socket rawip_socket } *;