untrusted_app.te revision 3a0ce49b8623299ac7458306b30bda6adda12383 
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 drmserver_service:service_manager find;
81allow untrusted_app healthd_service:service_manager find;
82allow untrusted_app mediaserver_service:service_manager find;
83allow untrusted_app mediaextractor_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# only allow unprivileged socket ioctl commands
91allowxperm untrusted_app self:{ rawip_socket tcp_socket udp_socket } ioctl unpriv_sock_ioctls;
92
93# Allow GMS core to access perfprofd output, which is stored
94# in /data/misc/perfprofd/. GMS core will need to list all
95# data stored in that directory to process them one by one.
96userdebug_or_eng(`
97  allow untrusted_app perfprofd_data_file:file r_file_perms;
98  allow untrusted_app perfprofd_data_file:dir r_dir_perms;
99')
100
101# gdbserver for ndk-gdb ptrace attaches to app process.
102allow untrusted_app self:process ptrace;
103
104# Programs routinely attempt to scan through /system, looking
105# for files. Suppress the denials when they occur.
106dontaudit untrusted_app exec_type:file getattr;
107
108###
109### neverallow rules
110###
111
112# Receive or send uevent messages.
113neverallow untrusted_app domain:netlink_kobject_uevent_socket *;
114
115# Receive or send generic netlink messages
116neverallow untrusted_app domain:netlink_socket *;
117
118# Too much leaky information in debugfs. It's a security
119# best practice to ensure these files aren't readable.
120neverallow untrusted_app debugfs:file read;
121
122# Do not allow untrusted apps to register services.
123# Only trusted components of Android should be registering
124# services.
125neverallow untrusted_app service_manager_type:service_manager add;
126
127# Do not allow untrusted_apps to connect to the property service
128# or set properties. b/10243159
129neverallow untrusted_app property_socket:sock_file write;
130neverallow untrusted_app init:unix_stream_socket connectto;
131neverallow untrusted_app property_type:property_service set;
132
133# Do not allow untrusted_app to be assigned mlstrustedsubject.
134# This would undermine the per-user isolation model being
135# enforced via levelFrom=user in seapp_contexts and the mls
136# constraints.  As there is no direct way to specify a neverallow
137# on attribute assignment, this relies on the fact that fork
138# permission only makes sense within a domain (hence should
139# never be granted to any other domain within mlstrustedsubject)
140# and untrusted_app is allowed fork permission to itself.
141neverallow untrusted_app mlstrustedsubject:process fork;
142
143# Do not allow untrusted_app to hard link to any files.
144# In particular, if untrusted_app links to other app data
145# files, installd will not be able to guarantee the deletion
146# of the linked to file. Hard links also contribute to security
147# bugs, so we want to ensure untrusted_app never has this
148# capability.
149neverallow untrusted_app file_type:file link;
150
151# Do not allow untrusted_app to access network MAC address file
152neverallow untrusted_app sysfs_mac_address:file no_rw_file_perms;
153
154# do not allow privileged socket ioctl commands
155neverallowxperm untrusted_app self:{ rawip_socket tcp_socket udp_socket } ioctl priv_sock_ioctls;
156
157# Do not allow untrusted_app access to /cache
158neverallow untrusted_app cache_file:dir ~{ r_dir_perms };
159neverallow untrusted_app cache_file:file ~{ read getattr };
160