4738b93db2
Executing files from an application home directory violates W^X (https://en.wikipedia.org/wiki/W%5EX) constraints (loading executable code from a writable file) and is an unsafe application behavior. Test to see if we can get rid of it and establish some baseline metrics. Test: device boots and no obvious problems. Change-Id: I756c281fcbf750821307327642cc0d06605951b0
87 lines
3.5 KiB
Text
87 lines
3.5 KiB
Text
###
|
|
### 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 { app_data_file privapp_data_file }:file {r_file_perms execute};
|
|
|
|
# Executing files from an application home directory violates
|
|
# W^X (https://en.wikipedia.org/wiki/W%5EX) constraints (loading executable code
|
|
# from a writable file) and is an unsafe application behavior. Test to see if we
|
|
# can get rid of it.
|
|
auditallow ephemeral_app app_data_file:file execute;
|
|
|
|
# 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;
|