untrusted_app.te revision b03831fe58be86cfd94c31b91def6ae53ebd614f 
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, domain_deprecated;
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
32# Third party vpn apps receive an open tun fd from the framework for
33# device traffic. Do not allow untrusted app to directly open tun_device
34allow untrusted_app tun_device:chr_file { read write getattr ioctl append };
35
36# ASEC
37allow untrusted_app asec_apk_file:file r_file_perms;
38# Execute libs in asec containers.
39allow untrusted_app asec_public_file:file { execute execmod };
40
41# Allow the allocation and use of ptys
42# Used by: https://play.google.com/store/apps/details?id=jackpal.androidterm
43create_pty(untrusted_app)
44
45# Used by Finsky / Android "Verify Apps" functionality when
46# running "adb install foo.apk".
47# TODO: Long term, we don't want apps probing into shell data files.
48# Figure out a way to remove these rules.
49allow untrusted_app shell_data_file:file r_file_perms;
50allow untrusted_app shell_data_file:dir r_dir_perms;
51
52# Read and write system app data files passed over Binder.
53# Motivating case was /data/data/com.android.settings/cache/*.jpg for
54# cropping or taking user photos.
55allow untrusted_app system_app_data_file:file { read write getattr };
56
57#
58# Rules migrated from old app domains coalesced into untrusted_app.
59# This includes what used to be media_app, shared_app, and release_app.
60#
61
62# Access /dev/mtp_usb.
63# TODO android.process.media moved to priv_app domain. Does
64# untrusted_app still require these permissions? Can "open"
65# be removed?
66allow untrusted_app mtp_device:chr_file rw_file_perms;
67auditallow untrusted_app mtp_device:chr_file rw_file_perms;
68
69# Access to /data/media.
70allow untrusted_app media_rw_data_file:dir create_dir_perms;
71allow untrusted_app media_rw_data_file:file create_file_perms;
72
73# Traverse into /mnt/media_rw for bypassing FUSE daemon
74# TODO: narrow this to just MediaProvider
75allow untrusted_app mnt_media_rw_file:dir search;
76
77# allow cts to query all services
78allow untrusted_app servicemanager:service_manager list;
79
80allow untrusted_app audioserver_service:service_manager find;
81allow untrusted_app drmserver_service:service_manager find;
82allow untrusted_app healthd_service:service_manager find;
83allow untrusted_app mediaserver_service:service_manager find;
84allow untrusted_app mediaextractor_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# Allow GMS core to access perfprofd output, which is stored
91# in /data/misc/perfprofd/. GMS core will need to list all
92# data stored in that directory to process them one by one.
93userdebug_or_eng(`
94  allow untrusted_app perfprofd_data_file:file r_file_perms;
95  allow untrusted_app perfprofd_data_file:dir r_dir_perms;
96')
97
98# gdbserver for ndk-gdb ptrace attaches to app process.
99allow untrusted_app self:process ptrace;
100
101# Programs routinely attempt to scan through /system, looking
102# for files. Suppress the denials when they occur.
103dontaudit untrusted_app exec_type:file getattr;
104
105###
106### neverallow rules
107###
108
109# Receive or send uevent messages.
110neverallow untrusted_app domain:netlink_kobject_uevent_socket *;
111
112# Receive or send generic netlink messages
113neverallow untrusted_app domain:netlink_socket *;
114
115# Too much leaky information in debugfs. It's a security
116# best practice to ensure these files aren't readable.
117neverallow untrusted_app debugfs:file read;
118
119# Do not allow untrusted apps to register services.
120# Only trusted components of Android should be registering
121# services.
122neverallow untrusted_app service_manager_type:service_manager add;
123
124# Do not allow untrusted_apps to connect to the property service
125# or set properties. b/10243159
126neverallow untrusted_app property_socket:sock_file write;
127neverallow untrusted_app init:unix_stream_socket connectto;
128neverallow untrusted_app property_type:property_service set;
129
130# Do not allow untrusted_app to be assigned mlstrustedsubject.
131# This would undermine the per-user isolation model being
132# enforced via levelFrom=user in seapp_contexts and the mls
133# constraints.  As there is no direct way to specify a neverallow
134# on attribute assignment, this relies on the fact that fork
135# permission only makes sense within a domain (hence should
136# never be granted to any other domain within mlstrustedsubject)
137# and untrusted_app is allowed fork permission to itself.
138neverallow untrusted_app mlstrustedsubject:process fork;
139
140# Do not allow untrusted_app to hard link to any files.
141# In particular, if untrusted_app links to other app data
142# files, installd will not be able to guarantee the deletion
143# of the linked to file. Hard links also contribute to security
144# bugs, so we want to ensure untrusted_app never has this
145# capability.
146neverallow untrusted_app file_type:file link;
147
148# Do not allow untrusted_app to access network MAC address file
149neverallow untrusted_app sysfs_mac_address:file no_rw_file_perms;
150
151# Do not allow untrusted app to directly open tun_device
152neverallow untrusted_app tun_device:chr_file open;
153
154# Do not allow untrusted_app access to /cache
155neverallow untrusted_app cache_file:dir ~{ r_dir_perms };
156neverallow untrusted_app cache_file:file ~{ read getattr };
157