private/untrusted_app_all.te

###
### Untrusted_app_all.
###
### This file defines the rules shared by all untrusted app domains except
### ephemeral_app for instant apps.
### Apps are labeled based on mac_permissions.xml (maps signer and
### optionally package name to seinfo value) and seapp_contexts (maps UID
### and optionally seinfo value to domain for process and type for data
### directory).  The untrusted_app_all attribute is assigned to all default
### seapp_contexts for any app with UID between APP_AID (10000)
### and AID_ISOLATED_START (99000) if the app has no specific seinfo
### value as determined from mac_permissions.xml.  In current AOSP, this
### attribute is assigned to all non-system apps as well as to any system apps
### that are not signed by the platform key.  To move
### a system app into a specific domain, add a signer entry for it to
### mac_permissions.xml and assign it one of the pre-existing seinfo values
### or define and use a new seinfo value in both mac_permissions.xml and
### seapp_contexts.
###
### Note that rules that should apply to all untrusted apps must be in app.te or also
### added to ephemeral_app.te.

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

# 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 untrusted_app_all app_data_file:file { execute execute_no_trans };

# ASEC
allow untrusted_app_all asec_apk_file:file r_file_perms;
allow untrusted_app_all asec_apk_file:dir r_dir_perms;
# Execute libs in asec containers.
allow untrusted_app_all asec_public_file:file { execute };

# Used by Finsky / Android "Verify Apps" functionality when
# running "adb install foo.apk".
# TODO: Long term, we don't want apps probing into shell data files.
# Figure out a way to remove these rules.
allow untrusted_app_all shell_data_file:file r_file_perms;
allow untrusted_app_all shell_data_file:dir r_dir_perms;

# Allow traceur to pass file descriptors through a content provider to untrusted apps
# for the purpose of sharing files through e.g. gmail
allow untrusted_app_all trace_data_file:file { getattr read };

# untrusted apps should not be able to open trace data files, they should depend
# upon traceur to pass a file descriptor
neverallow untrusted_app_all trace_data_file:dir *;
neverallow untrusted_app_all trace_data_file:file { no_w_file_perms open };

# Allow to read staged apks.
allow untrusted_app_all { apk_tmp_file apk_private_tmp_file }:file {read getattr};

# Read and write system app data files passed over Binder.
# Motivating case was /data/data/com.android.settings/cache/*.jpg for
# cropping or taking user photos.
allow untrusted_app_all system_app_data_file:file { read write getattr };

#
# Rules migrated from old app domains coalesced into untrusted_app.
# This includes what used to be media_app, shared_app, and release_app.
#

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

# Traverse into /mnt/media_rw for bypassing FUSE daemon
# TODO: narrow this to just MediaProvider
allow untrusted_app_all mnt_media_rw_file:dir search;

# allow cts to query all services
allow untrusted_app_all servicemanager:service_manager list;

allow untrusted_app_all audioserver_service:service_manager find;
allow untrusted_app_all cameraserver_service:service_manager find;
allow untrusted_app_all drmserver_service:service_manager find;
allow untrusted_app_all mediaserver_service:service_manager find;
allow untrusted_app_all mediaextractor_service:service_manager find;
allow untrusted_app_all mediacodec_service:service_manager find;
allow untrusted_app_all mediametrics_service:service_manager find;
allow untrusted_app_all mediadrmserver_service:service_manager find;
allow untrusted_app_all nfc_service:service_manager find;
allow untrusted_app_all radio_service:service_manager find;
allow untrusted_app_all app_api_service:service_manager find;
allow untrusted_app_all vr_manager_service:service_manager find;

# 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 untrusted_app_all perfprofd_data_file:file r_file_perms;
  allow untrusted_app_all perfprofd_data_file:dir r_dir_perms;
')

# gdbserver for ndk-gdb ptrace attaches to app process.
allow untrusted_app_all self:process ptrace;

# Cts: HwRngTest
allow untrusted_app_all sysfs_hwrandom:dir search;
allow untrusted_app_all sysfs_hwrandom:file r_file_perms;

# Allow apps to view preloaded media content
allow untrusted_app_all preloads_media_file:dir r_dir_perms;
allow untrusted_app_all preloads_media_file:file r_file_perms;
allow untrusted_app_all preloads_data_file:dir search;

# Allow untrusted apps read / execute access to /vendor/app for there can
# be pre-installed vendor apps that package a library within themselves.
# TODO (b/37784178) Consider creating  a special type for /vendor/app installed
# apps.
allow untrusted_app_all vendor_app_file:dir { open getattr read search };
allow untrusted_app_all vendor_app_file:file { open getattr read execute };
allow untrusted_app_all vendor_app_file:lnk_file { open getattr read };

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

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

# This is allowed for targetSdkVersion <= 25 but disallowed on newer versions.
dontaudit untrusted_app_all net_dns_prop:file read;

# These have been disallowed since Android O.
# For P, we assume that apps are safely handling the denial.
dontaudit untrusted_app_all proc_stat:file read;
dontaudit untrusted_app_all proc_vmstat:file read;
dontaudit untrusted_app_all proc_uptime:file read;

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

# /proc/net access.
# TODO(b/9496886) Audit access for removal.
# VPN apps require access to /proc/net/{tcp,udp} so access will need to be
# limited through a mechanism other than SELinux.
r_dir_file(untrusted_app_all, proc_net_type)
userdebug_or_eng(`
  auditallow untrusted_app_all {
    proc_net_type
    -proc_net_vpn
  }:{ dir file lnk_file } { getattr open read };
')

# 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 third party apps from spamming the logs.
dontaudit untrusted_app_all system_data_file:dir write;