platform_system_sepolicy/private/priv_app.te

###
### A domain for further sandboxing privileged apps.
###

typeattribute priv_app coredomain;
app_domain(priv_app)

# Access the network.
net_domain(priv_app)
# Access bluetooth.
bluetooth_domain(priv_app)

# Allow the allocation and use of ptys
# Used by: https://play.privileged.com/store/apps/details?id=jackpal.androidterm
create_pty(priv_app)

# webview crash handling depends on self ptrace (b/27697529, b/20150694, b/19277529#comment7)
allow priv_app self:process ptrace;

# Allow loading executable code from writable priv-app home
# directories. This is a W^X violation, however, it needs
# to be supported for now for the following reasons.
# * /data/user_*/0/*/code_cache/* POSSIBLE uses (b/117841367)
#   1) com.android.opengl.shaders_cache
#   2) com.android.skia.shaders_cache
#   3) com.android.renderscript.cache
# * /data/user_de/0/com.google.android.gms/app_chimera
# TODO: Tighten (b/112357170)
allow priv_app privapp_data_file:file execute;

allow priv_app privapp_data_file:lnk_file create_file_perms;

allow priv_app app_api_service:service_manager find;
allow priv_app audioserver_service:service_manager find;
allow priv_app cameraserver_service:service_manager find;
allow priv_app drmserver_service:service_manager find;
allow priv_app mediacodec_service:service_manager find;
allow priv_app mediadrmserver_service:service_manager find;
allow priv_app mediaextractor_service:service_manager find;
allow priv_app mediametrics_service:service_manager find;
allow priv_app mediaserver_service:service_manager find;
allow priv_app network_watchlist_service:service_manager find;
allow priv_app nfc_service:service_manager find;
allow priv_app oem_lock_service:service_manager find;
allow priv_app persistent_data_block_service:service_manager find;
allow priv_app radio_service:service_manager find;
allow priv_app recovery_service:service_manager find;
allow priv_app stats_service:service_manager find;
allow priv_app system_api_service:service_manager find;

# Write to /cache.
allow priv_app { cache_file cache_recovery_file }:dir create_dir_perms;
allow priv_app { cache_file cache_recovery_file }:file create_file_perms;
# /cache is a symlink to /data/cache on some devices. Allow reading the link.
allow priv_app cache_file:lnk_file r_file_perms;

# Write to /data/ota_package for OTA packages.
allow priv_app ota_package_file:dir rw_dir_perms;
allow priv_app ota_package_file:file create_file_perms;

# Access to /data/media.
allow priv_app media_rw_data_file:dir create_dir_perms;
allow priv_app media_rw_data_file:file create_file_perms;

# Used by Finsky / Android "Verify Apps" functionality when
# running "adb install foo.apk".
allow priv_app shell_data_file:file r_file_perms;
allow priv_app shell_data_file:dir r_dir_perms;

# Allow traceur to pass file descriptors through a content provider to betterbug
allow priv_app trace_data_file:file { getattr read };

# Allow verifier to access staged apks.
allow priv_app { apk_tmp_file apk_private_tmp_file }:dir r_dir_perms;
allow priv_app { apk_tmp_file apk_private_tmp_file }:file r_file_perms;

# b/18504118: Allow reads from /data/anr/traces.txt
allow priv_app anr_data_file:file r_file_perms;

# Allow GMS core to access perfprofd output, which is stored
# in /data/misc/perfprofd/. GMS core will need to list all
# data stored in that directory to process them one by one.
userdebug_or_eng(`
  allow priv_app perfprofd_data_file:file r_file_perms;
  allow priv_app perfprofd_data_file:dir r_dir_perms;
')

# For AppFuse.
allow priv_app vold:fd use;
allow priv_app fuse_device:chr_file { read write };

# /proc access
allow priv_app {
  proc_vmstat
}:file r_file_perms;

allow priv_app sysfs_type:dir search;
# Read access to /sys/class/net/wlan*/address
r_dir_file(priv_app, sysfs_net)
# Read access to /sys/block/zram*/mm_stat
r_dir_file(priv_app, sysfs_zram)

r_dir_file(priv_app, rootfs)

# Allow GMS core to open kernel config for OTA matching through libvintf
allow priv_app config_gz:file { open read getattr };

# access the mac address
allowxperm priv_app self:udp_socket ioctl SIOCGIFHWADDR;

# Allow GMS core to communicate with update_engine for A/B update.
binder_call(priv_app, update_engine)
allow priv_app update_engine_service:service_manager find;

# Allow GMS core to communicate with dumpsys storaged.
binder_call(priv_app, storaged)
allow priv_app storaged_service:service_manager find;

# Allow GMS core to access system_update_service (e.g. to publish pending
# system update info).
allow priv_app system_update_service:service_manager find;

# Allow GMS core to communicate with statsd.
binder_call(priv_app, statsd)

# Allow Phone to read/write cached ringtones (opened by system).
allow priv_app ringtone_file:file { getattr read write };

# Access to /data/preloads
allow priv_app preloads_data_file:file r_file_perms;
allow priv_app preloads_data_file:dir r_dir_perms;
allow priv_app preloads_media_file:file r_file_perms;
allow priv_app preloads_media_file:dir r_dir_perms;

# Allow privileged apps (e.g. GMS core) to generate unique hardware IDs
allow priv_app keystore:keystore_key gen_unique_id;

# Allow GMS core to access /sys/fs/selinux/policyvers for compatibility check
allow priv_app selinuxfs:file r_file_perms;

read_runtime_log_tags(priv_app)

# 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 priv_app traced:fd use;
allow priv_app traced_tmpfs:file { read write getattr map };
unix_socket_connect(priv_app, traced_producer, traced)

# Allow heap profiling if the app opts in by being marked
# profileable/debuggable.
can_profile_heap(priv_app)

# suppress denials for non-API accesses.
dontaudit priv_app exec_type:file getattr;
dontaudit priv_app device:dir read;
dontaudit priv_app fs_bpf:dir search;
dontaudit priv_app net_dns_prop:file read;
dontaudit priv_app proc:file read;
dontaudit priv_app proc_interrupts:file read;
dontaudit priv_app proc_modules:file read;
dontaudit priv_app proc_stat:file read;
dontaudit priv_app proc_version:file read;
dontaudit priv_app sysfs:dir read;
dontaudit priv_app sysfs:file read;
dontaudit priv_app sysfs_android_usb:file read;
dontaudit priv_app wifi_prop:file read;
dontaudit priv_app { wifi_prop exported_wifi_prop }:file read;

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

# Attempts to write to system_data_file is generally a sign
# that apps are attempting to access encrypted storage before
# the ACTION_USER_UNLOCKED intent is delivered. Suppress this
# denial to prevent apps from spamming the logs.
dontaudit priv_app system_data_file:dir write;

###
### neverallow rules
###

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

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

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

# Do not allow privileged apps to register services.
# Only trusted components of Android should be registering
# services.
neverallow priv_app service_manager_type:service_manager add;

# Do not allow privileged apps to connect to the property service
# or set properties. b/10243159
neverallow priv_app property_socket:sock_file write;
neverallow priv_app init:unix_stream_socket connectto;
neverallow priv_app property_type:property_service set;

# Do not allow priv_app to be assigned mlstrustedsubject.
# This would undermine the per-user isolation model being
# enforced via levelFrom=user in seapp_contexts and the mls
# constraints.  As there is no direct way to specify a neverallow
# on attribute assignment, this relies on the fact that fork
# permission only makes sense within a domain (hence should
# never be granted to any other domain within mlstrustedsubject)
# and priv_app is allowed fork permission to itself.
neverallow priv_app mlstrustedsubject:process fork;

# Do not allow priv_app to hard link to any files.
# In particular, if priv_app links to other app data
# files, installd will not be able to guarantee the deletion
# of the linked to file. Hard links also contribute to security
# bugs, so we want to ensure priv_app never has this
# capability.
neverallow priv_app file_type:file link;

# priv apps should not be able to open trace data files, they should depend
# upon traceur to pass a file descriptor which they can then read
neverallow priv_app trace_data_file:dir *;
neverallow priv_app trace_data_file:file { no_w_file_perms open };

# Do not allow priv_app access to cgroups.
neverallow priv_app cgroup:file *;

# Do not allow loading executable code from non-privileged
# application home directories. Code loading across a security boundary
# is dangerous and allows a full compromise of a privileged process
# by an unprivileged process. b/112357170
neverallow priv_app app_data_file:file no_x_file_perms;

# Do not follow untrusted app provided symlinks
neverallow priv_app app_data_file:lnk_file { open read getattr };