private/ephemeral_app.te

###
### Ephemeral apps.
###
### This file defines the security policy for apps with the ephemeral
### feature.
###
### The ephemeral_app domain is a reduced permissions sandbox allowing
### ephemeral applications to be safely installed and run. Non ephemeral
### applications may also opt-in to ephemeral to take advantage of the
### additional security features.
###
### PackageManager flags an app as ephemeral at install time.

typeattribute ephemeral_app coredomain;

net_domain(ephemeral_app)
app_domain(ephemeral_app)

# Allow ephemeral apps to read/write files in visible storage if provided fds
allow ephemeral_app { sdcard_type media_rw_data_file }:file {read write getattr ioctl lock append};

# Some apps ship with shared libraries and binaries that they write out
# to their sandbox directory and then execute.
allow ephemeral_app privapp_data_file:file { r_file_perms execute };
allow ephemeral_app app_data_file:file     { r_file_perms execute };

# Allow the renderscript compiler to be run.
domain_auto_trans(ephemeral_app, rs_exec, rs)

# Allow loading and deleting renderscript created shared libraries
# within an application home directory.
allow ephemeral_app rs_data_file:file { r_file_perms execute unlink };

# services
allow ephemeral_app audioserver_service:service_manager find;
allow ephemeral_app cameraserver_service:service_manager find;
allow ephemeral_app mediaserver_service:service_manager find;
allow ephemeral_app mediaextractor_service:service_manager find;
allow ephemeral_app mediacodec_service:service_manager find;
allow ephemeral_app mediametrics_service:service_manager find;
allow ephemeral_app mediadrmserver_service:service_manager find;
allow ephemeral_app drmserver_service:service_manager find;
allow ephemeral_app radio_service:service_manager find;
allow ephemeral_app ephemeral_app_api_service:service_manager find;

# Write app-specific trace data to the Perfetto traced damon. This requires
# connecting to its producer socket and obtaining a (per-process) tmpfs fd.
allow ephemeral_app traced:fd use;
allow ephemeral_app traced_tmpfs:file { read write getattr map };
unix_socket_connect(ephemeral_app, traced_producer, traced)

# allow ephemeral apps to use UDP sockets provided by the system server but not
# modify them other than to connect
allow ephemeral_app system_server:udp_socket {
        connect getattr read recvfrom sendto write getopt setopt };

###
### neverallow rules
###

neverallow ephemeral_app { app_data_file privapp_data_file }:file execute_no_trans;

# Receive or send uevent messages.
neverallow ephemeral_app domain:netlink_kobject_uevent_socket *;

# Receive or send generic netlink messages
neverallow ephemeral_app domain:netlink_socket *;

# Too much leaky information in debugfs. It's a security
# best practice to ensure these files aren't readable.
neverallow ephemeral_app debugfs:file read;

# execute gpu_device
neverallow ephemeral_app gpu_device:chr_file execute;

# access files in /sys with the default sysfs label
neverallow ephemeral_app sysfs:file *;

# Avoid reads from generically labeled /proc files
# Create a more specific label if needed
neverallow ephemeral_app proc:file { no_rw_file_perms no_x_file_perms };

# Directly access external storage
neverallow ephemeral_app { sdcard_type media_rw_data_file }:file {open create};
neverallow ephemeral_app { sdcard_type media_rw_data_file }:dir search;

# Avoid reads to proc_net, it contains too much device wide information about
# ongoing connections.
neverallow ephemeral_app proc_net:file no_rw_file_perms;