1### 2### Untrusted apps. 3### 4### This file defines the rules for untrusted apps. 5### Apps are labeled based on mac_permissions.xml (maps signer and 6### optionally package name to seinfo value) and seapp_contexts (maps UID 7### and optionally seinfo value to domain for process and type for data 8### directory). The untrusted_app domain is the default assignment in 9### seapp_contexts for any app with UID between APP_AID (10000) 10### and AID_ISOLATED_START (99000) if the app has no specific seinfo 11### value as determined from mac_permissions.xml. In current AOSP, this 12### domain is assigned to all non-system apps as well as to any system apps 13### that are not signed by the platform key. To move 14### a system app into a specific domain, add a signer entry for it to 15### mac_permissions.xml and assign it one of the pre-existing seinfo values 16### or define and use a new seinfo value in both mac_permissions.xml and 17### seapp_contexts. 18### 19### untrusted_app includes all the appdomain rules, plus the 20### additional following rules: 21### 22 23type untrusted_app, domain; 24app_domain(untrusted_app) 25net_domain(untrusted_app) 26bluetooth_domain(untrusted_app) 27 28# Some apps ship with shared libraries and binaries that they write out 29# to their sandbox directory and then execute. 30allow untrusted_app app_data_file:file { rx_file_perms execmod }; 31 32allow untrusted_app tun_device:chr_file rw_file_perms; 33 34# ASEC 35allow untrusted_app asec_apk_file:file r_file_perms; 36# Execute libs in asec containers. 37allow untrusted_app asec_public_file:file { execute execmod }; 38 39# Allow the allocation and use of ptys 40# Used by: https://play.google.com/store/apps/details?id=jackpal.androidterm 41create_pty(untrusted_app) 42 43# Used by Finsky / Android "Verify Apps" functionality when 44# running "adb install foo.apk". 45# TODO: Long term, we don't want apps probing into shell data files. 46# Figure out a way to remove these rules. 47allow untrusted_app shell_data_file:file r_file_perms; 48allow untrusted_app shell_data_file:dir r_dir_perms; 49 50# b/18504118: Allow reads from /data/anr/traces.txt 51# TODO: We shouldn't be allowing all untrusted_apps to read 52# this file. This is only needed for the GMS feedback agent. 53# See also b/18340553. GMS runs as untrusted_app, and 54# it's too late to change the domain it runs in. 55# This line needs to be deleted. 56allow untrusted_app anr_data_file:file r_file_perms; 57 58# Read and write system app data files passed over Binder. 59# Motivating case was /data/data/com.android.settings/cache/*.jpg for 60# cropping or taking user photos. 61allow untrusted_app system_app_data_file:file { read write getattr }; 62 63# 64# Rules migrated from old app domains coalesced into untrusted_app. 65# This includes what used to be media_app, shared_app, and release_app. 66# 67 68# Access /dev/mtp_usb. 69allow untrusted_app mtp_device:chr_file rw_file_perms; 70 71# Access to /data/media. 72allow untrusted_app media_rw_data_file:dir create_dir_perms; 73allow untrusted_app media_rw_data_file:file create_file_perms; 74 75# Traverse into /mnt/media_rw for bypassing FUSE daemon 76# TODO: narrow this to just MediaProvider 77allow untrusted_app mnt_media_rw_file:dir search; 78 79# Write to /cache. 80allow untrusted_app cache_file:dir create_dir_perms; 81allow untrusted_app cache_file:file create_file_perms; 82 83allow untrusted_app drmserver_service:service_manager find; 84allow untrusted_app mediaserver_service:service_manager find; 85allow untrusted_app nfc_service:service_manager find; 86allow untrusted_app radio_service:service_manager find; 87allow untrusted_app surfaceflinger_service:service_manager find; 88allow untrusted_app app_api_service:service_manager find; 89 90# TODO: remove this once priv-apps are no longer running in untrusted_app 91allow untrusted_app system_api_service:service_manager find; 92 93# TODO: remove and replace with specific package that accesses this 94allow untrusted_app persistent_data_block_service:service_manager find; 95 96# Allow verifier to access staged apks. 97allow untrusted_app { apk_tmp_file apk_private_tmp_file }:dir r_dir_perms; 98allow untrusted_app { apk_tmp_file apk_private_tmp_file }:file r_file_perms; 99 100# only allow unprivileged socket ioctl commands 101allow untrusted_app self:{ rawip_socket tcp_socket udp_socket } unpriv_sock_ioctls; 102 103# Allow GMS core to access perfprofd output, which is stored 104# in /data/misc/perfprofd/. GMS core will need to list all 105# data stored in that directory to process them one by one. 106userdebug_or_eng(` 107 allow untrusted_app perfprofd_data_file:file r_file_perms; 108 allow untrusted_app perfprofd_data_file:dir r_dir_perms; 109') 110 111# Programs routinely attempt to scan through /system, looking 112# for files. Suppress the denials when they occur. 113dontaudit untrusted_app exec_type:file getattr; 114 115### 116### neverallow rules 117### 118 119# Receive or send uevent messages. 120neverallow untrusted_app domain:netlink_kobject_uevent_socket *; 121 122# Receive or send generic netlink messages 123neverallow untrusted_app domain:netlink_socket *; 124 125# Too much leaky information in debugfs. It's a security 126# best practice to ensure these files aren't readable. 127neverallow untrusted_app debugfs:file read; 128 129# Do not allow untrusted apps to register services. 130# Only trusted components of Android should be registering 131# services. 132neverallow untrusted_app service_manager_type:service_manager add; 133 134# Do not allow untrusted_apps to connect to the property service 135# or set properties. b/10243159 136neverallow untrusted_app property_socket:sock_file write; 137neverallow untrusted_app init:unix_stream_socket connectto; 138neverallow untrusted_app property_type:property_service set; 139 140# Do not allow untrusted_app to be assigned mlstrustedsubject. 141# This would undermine the per-user isolation model being 142# enforced via levelFrom=user in seapp_contexts and the mls 143# constraints. As there is no direct way to specify a neverallow 144# on attribute assignment, this relies on the fact that fork 145# permission only makes sense within a domain (hence should 146# never be granted to any other domain within mlstrustedsubject) 147# and untrusted_app is allowed fork permission to itself. 148neverallow untrusted_app mlstrustedsubject:process fork; 149 150# Do not allow untrusted_app to hard link to any files. 151# In particular, if untrusted_app links to other app data 152# files, installd will not be able to guarantee the deletion 153# of the linked to file. Hard links also contribute to security 154# bugs, so we want to ensure untrusted_app never has this 155# capability. 156neverallow untrusted_app file_type:file link; 157