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)

# 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;

# Chrome Crashpad uses the the dynamic linker to load native executables
# from an APK (b/112050209, crbug.com/928422)
allow priv_app system_linker_exec:file execute_no_trans;

allow priv_app privapp_data_file:lnk_file create_file_perms;

# Priv apps can find services that expose both @SystemAPI and normal APIs.
allow priv_app app_api_service:service_manager find;
allow priv_app system_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 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 music_recognition_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;

# 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;

# 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 betterbug to read profile reports generated by profcollect.
userdebug_or_eng(`
  allow priv_app profcollectd_data_file:file r_file_perms;
')

# Allow the bug reporting frontend to read the presence and timestamp of the
# trace attached to the bugreport (but not its contents, which will go in the
# usual bugreport .zip file). This is used by the bug reporting UI to tell if
# the bugreport will contain a system trace or not while the bugreport is still
# in progress.
allow priv_app wm_trace_data_file:dir r_dir_perms;
allow priv_app wm_trace_data_file:file getattr;
allow priv_app perfetto_traces_bugreport_data_file:dir r_dir_perms;
allow priv_app perfetto_traces_bugreport_data_file:file { getattr };
# Required to traverse the parent dir (/data/misc/perfetto-traces).
allow priv_app perfetto_traces_data_file:dir { search };

# Allow priv apps (e.g. BetterBug) to receive Perfetto traces through
# the framework (i.e. TracingServiceProxy) and sendfile them into their private
# directories for reporting when network and battery conditions are
# appropriate.
allow priv_app perfetto:fd use;
allow priv_app perfetto_traces_data_file:file { read getattr };

# 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;
allowxperm priv_app { apk_tmp_file apk_private_tmp_file }:file ioctl FS_IOC_MEASURE_VERITY;

# 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/block/zram*/mm_stat
r_dir_file(priv_app, sysfs_zram)

r_dir_file(priv_app, rootfs)

# Allow com.android.vending 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;

read_runtime_log_tags(priv_app)

# Allow priv_apps to request and collect incident reports.
# (Also requires DUMP and PACKAGE_USAGE_STATS permissions)
allow priv_app incident_service:service_manager find;
binder_call(priv_app, incidentd)
allow priv_app incidentd:fifo_file { read write };

# Allow priv_apps to check whether Dynamic System Update is enabled
get_prop(priv_app, dynamic_system_prop)

# Allow privileged apps to read trade in mode property
get_prop(priv_app, adbd_tradeinmode_prop)

# 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_net: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 sysfs_dm:file r_file_perms;
dontaudit priv_app { wifi_prop wifi_config_prop wifi_hal_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 };

# allow apps like Phonesky to check the file signature of an apk installed on
# the Incremental File System, fill missing blocks and get the app status and loading progress
allowxperm priv_app apk_data_file:file ioctl {
  INCFS_IOCTL_READ_SIGNATURE
  INCFS_IOCTL_FILL_BLOCKS
  INCFS_IOCTL_GET_BLOCK_COUNT
  INCFS_IOCTL_GET_FILLED_BLOCKS
};

# allow privileged data loader apps (e.g. com.android.vending) to read logs from Incremental File System
allow priv_app incremental_control_file:file { read getattr ioctl };

# allow apps like Phonesky to request permission to fill blocks of an apk file
# on the Incremental File System.
allowxperm priv_app incremental_control_file:file ioctl INCFS_IOCTL_PERMIT_FILL;

# allow privileged apps to read the vendor property that indicates if Incremental File System is enabled
get_prop(priv_app, incremental_prop)

# allow privileged apps to read the device config flags.
get_prop(priv_app, device_config_aconfig_flags_prop)

# allow privileged apps to read boot reason property
get_prop(priv_app, system_boot_reason_prop)

# Required for Phonesky to be able to read APEX files under /data/apex/active/.
allow priv_app apex_data_file:dir search;
allow priv_app staging_data_file:file r_file_perms;
# Required for Phonesky to be able to read staged files under /data/app-staging.
allow priv_app staging_data_file:dir r_dir_perms;

# Allow com.android.vending to access files under vendor/apex as well as system apex files.
# This is required for com.android.vending to handle APEXes for e.g. delta patch optimization.
allow priv_app vendor_apex_file:dir r_dir_perms;
allow priv_app vendor_apex_file:file r_file_perms;

# allow priv app to access the system app data files for ContentProvider case.
allow priv_app system_app_data_file:file { read getattr };

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

# Allow loading and deleting executable shared libraries
# within an application home directory. Such shared libraries would be
# created by things like renderscript or via other mechanisms.
allow priv_app app_exec_data_file:file { r_file_perms execute unlink };

# Allow privileged apps to create a VM. Note that access is still
# guarded with the `android.permission.MANAGE_VIRTUAL_MACHINE`
# permission.
virtualizationservice_use(priv_app)

###
### 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 *;

# Read or write kernel printk buffer
neverallow priv_app kmsg_device:chr_file no_rw_file_perms;

# Too much leaky information in debugfs. It's a security
# best practice to ensure these files aren't readable.
neverallow priv_app debugfs_type: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 *;
neverallow priv_app cgroup_v2: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_type -privapp_data_file }:file no_x_file_perms;

# Do not follow any app provided symlinks
neverallow priv_app { app_data_file_type -privapp_data_file }:lnk_file { open read getattr };

# Do not allow getting permission-protected network information from sysfs.
neverallow priv_app sysfs_net:file *;

# Restrict socket ioctls. Either 1. disallow privileged ioctls, 2. disallow the
# ioctl permission, or 3. disallow the socket class.
neverallowxperm priv_app domain:{ icmp_socket rawip_socket tcp_socket udp_socket } ioctl priv_sock_ioctls;
neverallow priv_app *:{ netlink_route_socket netlink_selinux_socket } ioctl;
neverallow priv_app *:{
  socket netlink_socket packet_socket key_socket appletalk_socket
  netlink_tcpdiag_socket netlink_nflog_socket
  netlink_xfrm_socket netlink_audit_socket
  netlink_dnrt_socket netlink_kobject_uevent_socket tun_socket
  netlink_iscsi_socket netlink_fib_lookup_socket netlink_connector_socket
  netlink_netfilter_socket netlink_generic_socket netlink_scsitransport_socket
  netlink_rdma_socket netlink_crypto_socket sctp_socket
  ax25_socket ipx_socket netrom_socket atmpvc_socket x25_socket rose_socket decnet_socket
  atmsvc_socket rds_socket irda_socket pppox_socket llc_socket can_socket tipc_socket
  bluetooth_socket iucv_socket rxrpc_socket isdn_socket phonet_socket ieee802154_socket caif_socket
  alg_socket nfc_socket kcm_socket qipcrtr_socket smc_socket xdp_socket
} *;