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;

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 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 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 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;

# 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)

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

# 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)

# Write app-specific trace data to the Perfetto traced damon. This requires
# connecting to its producer socket and obtaining a (per-process) tmpfs fd.
perfetto_producer(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 profiling if the app opts in by being marked profileable/debuggable.
can_profile_heap(priv_app)
can_profile_perf(priv_app)

# Allow priv_apps to check whether Dynamic System Update is enabled
get_prop(priv_app, dynamic_system_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_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 };

# Access the IncFS list of features
r_dir_file(priv_app, sysfs_fs_incfs_features)

# 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
allowxperm priv_app apk_data_file:file ioctl {
  INCFS_IOCTL_READ_SIGNATURE
  INCFS_IOCTL_FILL_BLOCKS
  INCFS_IOCTL_GET_BLOCK_COUNT
};

# 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;

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

###
### 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: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 };