untrusted_app: policy versioning based on targetSdkVersion
Motivation:
Provide the ability to phase in new security policies by
applying them to apps with a minimum targetSdkVersion.
Place untrusted apps with targetSdkVersion<=25 into the
untrustd_app_25 domain. Apps with targetSdkVersion>=26 are placed
into the untrusted_app domain. Common rules are included in the
untrusted_app_all attribute. Apps with a more recent targetSdkVersion
are granted fewer permissions.
Test: Marlin builds and boots. Apps targeting targetSdkVersion<=25
run in untrusted_app_25 domain. Apps targeting the current development
build >=26 run in the untrusted_app domain with fewer permissions. No
new denials observed during testing.
Bug: 34115651
Bug: 35323421
Change-Id: Ie6a015566fac07c44ea06c963c40793fcdc9a083
diff --git a/private/app_neverallows.te b/private/app_neverallows.te
index 33670aa..a881d52 100644
--- a/private/app_neverallows.te
+++ b/private/app_neverallows.te
@@ -2,26 +2,33 @@
### neverallow rules for untrusted app domains
###
+# Only allow domains in AOSP to use the untrusted_app_all attribute.
+neverallow { untrusted_app_all -untrusted_app -untrusted_app_25 } domain:process fork;
+
# Receive or send uevent messages.
-neverallow { untrusted_app ephemeral_app isolated_app } domain:netlink_kobject_uevent_socket *;
+neverallow { untrusted_app_all ephemeral_app isolated_app } domain:netlink_kobject_uevent_socket *;
# Receive or send generic netlink messages
-neverallow { untrusted_app ephemeral_app isolated_app } domain:netlink_socket *;
+neverallow { untrusted_app_all ephemeral_app isolated_app } domain:netlink_socket *;
# Too much leaky information in debugfs. It's a security
# best practice to ensure these files aren't readable.
-neverallow { untrusted_app ephemeral_app isolated_app } debugfs_type:file read;
+neverallow { untrusted_app_all ephemeral_app isolated_app } debugfs_type:file read;
# Do not allow untrusted apps to register services.
# Only trusted components of Android should be registering
# services.
-neverallow { untrusted_app ephemeral_app isolated_app } service_manager_type:service_manager add;
+neverallow { untrusted_app_all ephemeral_app isolated_app } service_manager_type:service_manager add;
# Do not allow untrusted apps to connect to the property service
# or set properties. b/10243159
-neverallow { untrusted_app ephemeral_app isolated_app } property_socket:sock_file write;
-neverallow { untrusted_app ephemeral_app isolated_app } init:unix_stream_socket connectto;
-neverallow { untrusted_app ephemeral_app isolated_app } property_type:property_service set;
+neverallow { untrusted_app_all ephemeral_app isolated_app } property_socket:sock_file write;
+neverallow { untrusted_app_all ephemeral_app isolated_app } init:unix_stream_socket connectto;
+neverallow { untrusted_app_all ephemeral_app isolated_app } property_type:property_service set;
+
+# b/34115651 - net.dns* properties read
+# This will go away in a future Android release
+neverallow { appdomain -untrusted_app_25 } net_dns_prop:file r_file_perms;
# Do not allow untrusted apps to be assigned mlstrustedsubject.
# This would undermine the per-user isolation model being
@@ -31,7 +38,7 @@
# permission only makes sense within a domain (hence should
# never be granted to any other domain within mlstrustedsubject)
# and an untrusted app is allowed fork permission to itself.
-neverallow { untrusted_app ephemeral_app isolated_app } mlstrustedsubject:process fork;
+neverallow { untrusted_app_all ephemeral_app isolated_app } mlstrustedsubject:process fork;
# Do not allow untrusted apps to hard link to any files.
# In particular, if an untrusted app links to other app data
@@ -39,16 +46,16 @@
# of the linked to file. Hard links also contribute to security
# bugs, so we want to ensure untrusted apps never have this
# capability.
-neverallow { untrusted_app ephemeral_app isolated_app } file_type:file link;
+neverallow { untrusted_app_all ephemeral_app isolated_app } file_type:file link;
# Do not allow untrusted apps to access network MAC address file
-neverallow { untrusted_app ephemeral_app isolated_app } sysfs_mac_address:file no_rw_file_perms;
+neverallow { untrusted_app_all ephemeral_app isolated_app } sysfs_mac_address:file no_rw_file_perms;
# Restrict socket ioctls. Either 1. disallow privileged ioctls, 2. disallow the
# ioctl permission, or 3. disallow the socket class.
-neverallowxperm { untrusted_app ephemeral_app isolated_app } domain:{ rawip_socket tcp_socket udp_socket } ioctl priv_sock_ioctls;
-neverallow { untrusted_app ephemeral_app isolated_app } *:{ netlink_route_socket netlink_selinux_socket } ioctl;
-neverallow { untrusted_app ephemeral_app isolated_app } *:{
+neverallowxperm { untrusted_app_all ephemeral_app isolated_app } domain:{ rawip_socket tcp_socket udp_socket } ioctl priv_sock_ioctls;
+neverallow { untrusted_app_all ephemeral_app isolated_app } *:{ netlink_route_socket netlink_selinux_socket } ioctl;
+neverallow { untrusted_app_all ephemeral_app isolated_app } *:{
socket netlink_socket packet_socket key_socket appletalk_socket
netlink_tcpdiag_socket netlink_nflog_socket
netlink_xfrm_socket netlink_audit_socket
@@ -59,15 +66,15 @@
} *;
# Do not allow untrusted apps access to /cache
-neverallow { untrusted_app ephemeral_app isolated_app } { cache_file cache_recovery_file }:dir ~{ r_dir_perms };
-neverallow { untrusted_app ephemeral_app isolated_app } { cache_file cache_recovery_file }:file ~{ read getattr };
+neverallow { untrusted_app_all ephemeral_app isolated_app } { cache_file cache_recovery_file }:dir ~{ r_dir_perms };
+neverallow { untrusted_app_all ephemeral_app isolated_app } { cache_file cache_recovery_file }:file ~{ read getattr };
# Do not allow untrusted apps to create/unlink files outside of its sandbox,
# internal storage or sdcard.
# World accessible data locations allow application to fill the device
# with unaccounted for data. This data will not get removed during
# application un-installation.
-neverallow { untrusted_app ephemeral_app isolated_app } {
+neverallow { untrusted_app_all ephemeral_app isolated_app } {
fs_type
-fuse # sdcard
-sdcardfs # sdcard
@@ -85,12 +92,12 @@
}:dir_file_class_set { create unlink };
# Do not allow untrusted apps to directly open tun_device
-neverallow { untrusted_app ephemeral_app isolated_app } tun_device:chr_file open;
+neverallow { untrusted_app_all ephemeral_app isolated_app } tun_device:chr_file open;
# Only allow appending to /data/anr/traces.txt (b/27853304, b/18340553)
-neverallow { untrusted_app ephemeral_app isolated_app } anr_data_file:file ~{ open append };
-neverallow { untrusted_app ephemeral_app isolated_app } anr_data_file:dir ~search;
+neverallow { untrusted_app_all ephemeral_app isolated_app } anr_data_file:file ~{ open append };
+neverallow { untrusted_app_all ephemeral_app isolated_app } anr_data_file:dir ~search;
# Avoid reads from generically labeled /proc files
# Create a more specific label if needed
-neverallow { untrusted_app ephemeral_app isolated_app } proc:file { no_rw_file_perms no_x_file_perms };
+neverallow { untrusted_app_all ephemeral_app isolated_app } proc:file { no_rw_file_perms no_x_file_perms };
diff --git a/private/seapp_contexts b/private/seapp_contexts
index 098ee66..ee2740a 100644
--- a/private/seapp_contexts
+++ b/private/seapp_contexts
@@ -102,4 +102,5 @@
user=_app seinfo=platform domain=platform_app type=app_data_file levelFrom=user
user=_app isEphemeralApp=true domain=ephemeral_app type=app_data_file levelFrom=all
user=_app isPrivApp=true domain=priv_app type=app_data_file levelFrom=user
-user=_app domain=untrusted_app type=app_data_file levelFrom=user
+user=_app minTargetSdkVersion=26 domain=untrusted_app type=app_data_file levelFrom=user
+user=_app domain=untrusted_app_25 type=app_data_file levelFrom=user
diff --git a/private/untrusted_app.te b/private/untrusted_app.te
index 50d79ee..ead9a16 100644
--- a/private/untrusted_app.te
+++ b/private/untrusted_app.te
@@ -18,93 +18,6 @@
###
app_domain(untrusted_app)
+untrusted_app_domain(untrusted_app)
net_domain(untrusted_app)
bluetooth_domain(untrusted_app)
-
-# b/34115651 - net.dns* properties read
-# This will go away in a future Android release
-get_prop(untrusted_app, net_dns_prop)
-
-# Allow the allocation and use of ptys
-# Used by: https://play.google.com/store/apps/details?id=jackpal.androidterm
-create_pty(untrusted_app)
-
-# Legacy text relocations
-allow untrusted_app apk_data_file:file execmod;
-
-# Some apps ship with shared libraries and binaries that they write out
-# to their sandbox directory and then execute.
-allow untrusted_app app_data_file:file { rx_file_perms execmod };
-
-# ASEC
-allow untrusted_app asec_apk_file:file r_file_perms;
-allow untrusted_app asec_apk_file:dir r_dir_perms;
-# Execute libs in asec containers.
-allow untrusted_app asec_public_file:file { execute execmod };
-
-# 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 shell_data_file:file r_file_perms;
-allow untrusted_app shell_data_file:dir r_dir_perms;
-
-# 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 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 media_rw_data_file:dir create_dir_perms;
-allow untrusted_app 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 mnt_media_rw_file:dir search;
-
-# allow cts to query all services
-allow untrusted_app servicemanager:service_manager list;
-
-allow untrusted_app audioserver_service:service_manager find;
-allow untrusted_app cameraserver_service:service_manager find;
-allow untrusted_app drmserver_service:service_manager find;
-allow untrusted_app mediaserver_service:service_manager find;
-allow untrusted_app mediaextractor_service:service_manager find;
-allow untrusted_app mediacodec_service:service_manager find;
-allow untrusted_app mediametrics_service:service_manager find;
-allow untrusted_app mediadrmserver_service:service_manager find;
-allow untrusted_app nfc_service:service_manager find;
-allow untrusted_app radio_service:service_manager find;
-allow untrusted_app surfaceflinger_service:service_manager find;
-allow untrusted_app app_api_service:service_manager find;
-allow untrusted_app 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 perfprofd_data_file:file r_file_perms;
- allow untrusted_app perfprofd_data_file:dir r_dir_perms;
-')
-
-# gdbserver for ndk-gdb ptrace attaches to app process.
-allow untrusted_app self:process ptrace;
-
-# Cts: HwRngTest
-allow untrusted_app sysfs_hwrandom:dir search;
-allow untrusted_app sysfs_hwrandom:file r_file_perms;
-
-# Allow apps to view preloaded content
-allow untrusted_app preloads_data_file:dir r_dir_perms;
-allow untrusted_app preloads_data_file:file r_file_perms;
-
-# Access to /proc/tty/drivers, to allow apps to determine if they
-# are running in an emulated environment.
-# b/33214085 b/33814662 b/33791054 b/33211769
-# https://github.com/strazzere/anti-emulator/blob/master/AntiEmulator/src/diff/strazzere/anti/emulator/FindEmulator.java
-allow untrusted_app proc_tty_drivers:file r_file_perms;
diff --git a/private/untrusted_app_25.te b/private/untrusted_app_25.te
new file mode 100644
index 0000000..4f92649
--- /dev/null
+++ b/private/untrusted_app_25.te
@@ -0,0 +1,29 @@
+###
+### Untrusted_app_25
+###
+### This file defines the rules for untrusted apps running with
+### targetSdkVersion <= 25.
+###
+### 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 domain is the default assignment in
+### 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
+### domain 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.
+###
+
+app_domain(untrusted_app_25)
+untrusted_app_domain(untrusted_app_25)
+net_domain(untrusted_app_25)
+bluetooth_domain(untrusted_app_25)
+
+# b/34115651 - net.dns* properties read
+# This will go away in a future Android release
+get_prop(untrusted_app_25, net_dns_prop)
diff --git a/private/untrusted_app_all.te b/private/untrusted_app_all.te
new file mode 100644
index 0000000..7d6bee5
--- /dev/null
+++ b/private/untrusted_app_all.te
@@ -0,0 +1,102 @@
+###
+### Untrusted_app_all.
+###
+### This file defines the rules shared by all untrusted app domains.
+### 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.
+###
+
+# Allow the allocation and use of ptys
+# Used by: https://play.google.com/store/apps/details?id=jackpal.androidterm
+create_pty(untrusted_app)
+
+# Legacy text relocations
+allow untrusted_app_all apk_data_file:file execmod;
+
+# 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:file { rx_file_perms execmod };
+
+# 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 execmod };
+
+# 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;
+
+# 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 surfaceflinger_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 content
+allow untrusted_app_all preloads_data_file:dir r_dir_perms;
+allow untrusted_app_all preloads_data_file:file r_file_perms;
+
+# Access to /proc/tty/drivers, to allow apps to determine if they
+# are running in an emulated environment.
+# b/33214085 b/33814662 b/33791054 b/33211769
+# https://github.com/strazzere/anti-emulator/blob/master/AntiEmulator/src/diff/strazzere/anti/emulator/FindEmulator.java
+allow untrusted_app_all proc_tty_drivers:file r_file_perms;
diff --git a/public/attributes b/public/attributes
index 75db022..d9212fc 100644
--- a/public/attributes
+++ b/public/attributes
@@ -95,6 +95,9 @@
# All domains used for apps.
attribute appdomain;
+# All third party apps.
+attribute untrusted_app_all;
+
# All domains used for apps with network access.
attribute netdomain;
diff --git a/public/domain.te b/public/domain.te
index e2ffb88..9993f2f 100644
--- a/public/domain.te
+++ b/public/domain.te
@@ -499,7 +499,7 @@
# prohibit non-zygote spawned processes from using shared libraries
# with text relocations. b/20013628 .
-neverallow { domain -untrusted_app } file_type:file execmod;
+neverallow { domain -untrusted_app_all } file_type:file execmod;
neverallow { domain -init } proc:{ file dir } mounton;
diff --git a/public/te_macros b/public/te_macros
index 7a9eeb6..4e33427 100644
--- a/public/te_macros
+++ b/public/te_macros
@@ -128,6 +128,13 @@
')
#####################################
+# untrusted_app_domain(domain)
+# Allow a base set of permissions required for all untrusted apps.
+define(`untrusted_app_domain', `
+typeattribute $1 untrusted_app_all;
+')
+
+#####################################
# net_domain(domain)
# Allow a base set of permissions required for network access.
define(`net_domain', `
diff --git a/public/untrusted_app_25.te b/public/untrusted_app_25.te
new file mode 100644
index 0000000..4ca6e31
--- /dev/null
+++ b/public/untrusted_app_25.te
@@ -0,0 +1,20 @@
+###
+### Untrusted 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 domain is the default assignment in
+### 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
+### domain 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.
+###
+
+type untrusted_app_25, domain;
+