platform_system_sepolicy/private/app_neverallows.te
Michael Butler ea331aa7b8 Allow applications to use NN API HAL services
The NeuralNetworks runtime is a library that communicates with
NeuralNetworks HIDL services and is linked by applications. To enable
the NN runtime to use these services, applications must have explicit
sepolicy permissions to find the NN services and communicate across
binder.

This CL relaxes neverallow rules for hal_neuralnetworks_*.

Because it is affecting pre-existing neverallow rules, this CL requires
a CTS rebuild.

Bug: 70340780
Test: mm
Test: ran neuralnetworks vts and cts binaries
Change-Id: I84f73ac77486681f91d1f8687268c0fa22a7ba0b
(cherry picked from commit 598870bebc4bb34542df81799b46f3cdcfb6723b)
2018-01-16 13:50:37 -08:00

245 lines
9.6 KiB
Text

###
### neverallow rules for untrusted app domains
###
define(`all_untrusted_apps',`{
ephemeral_app
isolated_app
mediaprovider
untrusted_app
untrusted_app_25
untrusted_app_all
untrusted_v2_app
}')
# Receive or send uevent messages.
neverallow all_untrusted_apps domain:netlink_kobject_uevent_socket *;
# Receive or send generic netlink messages
neverallow all_untrusted_apps domain:netlink_socket *;
# Too much leaky information in debugfs. It's a security
# best practice to ensure these files aren't readable.
neverallow all_untrusted_apps debugfs_type:file read;
# Do not allow untrusted apps to register services.
# Only trusted components of Android should be registering
# services.
neverallow all_untrusted_apps service_manager_type:service_manager add;
# Do not allow untrusted apps to use VendorBinder
neverallow all_untrusted_apps vndbinder_device:chr_file *;
neverallow all_untrusted_apps vndservice_manager_type:service_manager *;
# Do not allow untrusted apps to connect to the property service
# or set properties. b/10243159
neverallow { all_untrusted_apps -mediaprovider } property_socket:sock_file write;
neverallow { all_untrusted_apps -mediaprovider } init:unix_stream_socket connectto;
neverallow { all_untrusted_apps -mediaprovider } property_type:property_service set;
# Do not allow untrusted apps to be assigned mlstrustedsubject.
# This would undermine the per-user isolation model being
# enforced via levelFrom=user in seapp_contexts and the mls
# constraints. As there is no direct way to specify a neverallow
# on attribute assignment, this relies on the fact that fork
# 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 all_untrusted_apps 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
# files, installd will not be able to guarantee the deletion
# of the linked to file. Hard links also contribute to security
# bugs, so we want to ensure untrusted apps never have this
# capability.
neverallow all_untrusted_apps file_type:file link;
# Do not allow untrusted apps to access network MAC address file
neverallow all_untrusted_apps sysfs_mac_address:file no_rw_file_perms;
# Do not allow any write access to files in /sys
neverallow all_untrusted_apps sysfs_type:file no_w_file_perms;
# Restrict socket ioctls. Either 1. disallow privileged ioctls, 2. disallow the
# ioctl permission, or 3. disallow the socket class.
neverallowxperm all_untrusted_apps domain:{ rawip_socket tcp_socket udp_socket } ioctl priv_sock_ioctls;
neverallow all_untrusted_apps *:{ netlink_route_socket netlink_selinux_socket } ioctl;
neverallow all_untrusted_apps *:{
socket netlink_socket packet_socket key_socket appletalk_socket
netlink_tcpdiag_socket netlink_nflog_socket
netlink_xfrm_socket netlink_audit_socket
netlink_dnrt_socket netlink_kobject_uevent_socket tun_socket
netlink_iscsi_socket netlink_fib_lookup_socket netlink_connector_socket
netlink_netfilter_socket netlink_generic_socket netlink_scsitransport_socket
netlink_rdma_socket netlink_crypto_socket
} *;
# Do not allow untrusted apps access to /cache
neverallow { all_untrusted_apps -mediaprovider } { cache_file cache_recovery_file }:dir ~{ r_dir_perms };
neverallow { all_untrusted_apps -mediaprovider } { 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 { all_untrusted_apps -mediaprovider } {
fs_type
-fuse # sdcard
-sdcardfs # sdcard
-vfat
file_type
-app_data_file # The apps sandbox itself
-media_rw_data_file # Internal storage. Known that apps can
# leave artfacts here after uninstall.
-user_profile_data_file # Access to profile files
userdebug_or_eng(`
-method_trace_data_file # only on ro.debuggable=1
-coredump_file # userdebug/eng only
')
}:dir_file_class_set { create unlink };
# No untrusted component should be touching /dev/fuse
neverallow all_untrusted_apps fuse_device:chr_file *;
# Do not allow untrusted apps to directly open tun_device
neverallow all_untrusted_apps tun_device:chr_file open;
# Only allow appending to /data/anr/traces.txt (b/27853304, b/18340553)
neverallow all_untrusted_apps anr_data_file:file ~{ open append };
neverallow all_untrusted_apps anr_data_file:dir ~search;
# Avoid reads from generically labeled /proc files
# Create a more specific label if needed
neverallow all_untrusted_apps {
proc
proc_asound
proc_filesystems
proc_kmsg
proc_loadavg
proc_mounts
proc_pagetypeinfo
proc_swaps
proc_version
proc_vmallocinfo
}:file { no_rw_file_perms no_x_file_perms };
# Avoid all access to kernel configuration
neverallow all_untrusted_apps config_gz:file { no_rw_file_perms no_x_file_perms };
# Do not allow untrusted apps access to preloads data files
neverallow all_untrusted_apps preloads_data_file:file no_rw_file_perms;
# Locking of files on /system could lead to denial of service attacks
# against privileged system components
neverallow all_untrusted_apps system_file:file lock;
# Do not permit untrusted apps to perform actions on HwBinder service_manager
# other than find actions for services listed below
neverallow all_untrusted_apps *:hwservice_manager ~find;
# Do not permit access from apps which host arbitrary code to HwBinder services,
# except those considered sufficiently safe for access from such apps.
# The two main reasons for this are:
# 1. HwBinder servers do not perform client authentication because HIDL
# currently does not expose caller UID information and, even if it did, many
# HwBinder services either operate at a level below that of apps (e.g., HALs)
# or must not rely on app identity for authorization. Thus, to be safe, the
# default assumption is that every HwBinder service treats all its clients as
# equally authorized to perform operations offered by the service.
# 2. HAL servers (a subset of HwBinder services) contain code with higher
# incidence rate of security issues than system/core components and have
# access to lower layes of the stack (all the way down to hardware) thus
# increasing opportunities for bypassing the Android security model.
#
# Safe services include:
# - same process services: because they by definition run in the process
# of the client and thus have the same access as the client domain in which
# the process runs
# - coredomain_hwservice: are considered safe because they do not pose risks
# associated with reason #2 above.
# - hal_configstore_ISurfaceFlingerConfigs: becuase it has specifically been
# designed for use by any domain.
# - hal_graphics_allocator_hwservice: because these operations are also offered
# by surfaceflinger Binder service, which apps are permitted to access
# - hal_omx_hwservice: because this is a HwBinder version of the mediacodec
# Binder service which apps were permitted to access.
neverallow all_untrusted_apps {
hwservice_manager_type
-same_process_hwservice
-coredomain_hwservice
-hal_configstore_ISurfaceFlingerConfigs
-hal_graphics_allocator_hwservice
-hal_omx_hwservice
-hal_cas_hwservice
-hal_neuralnetworks_hwservice
-untrusted_app_visible_hwservice
}:hwservice_manager find;
# Make sure that the following services are never accessible by untrusted_apps
neverallow all_untrusted_apps {
default_android_hwservice
hal_audio_hwservice
hal_bluetooth_hwservice
hal_bootctl_hwservice
hal_camera_hwservice
hal_contexthub_hwservice
hal_drm_hwservice
hal_dumpstate_hwservice
hal_fingerprint_hwservice
hal_gatekeeper_hwservice
hal_gnss_hwservice
hal_graphics_composer_hwservice
hal_health_hwservice
hal_ir_hwservice
hal_keymaster_hwservice
hal_light_hwservice
hal_memtrack_hwservice
hal_nfc_hwservice
hal_oemlock_hwservice
hal_power_hwservice
hal_sensors_hwservice
hal_telephony_hwservice
hal_thermal_hwservice
hal_tv_cec_hwservice
hal_tv_input_hwservice
hal_usb_hwservice
hal_vibrator_hwservice
hal_vr_hwservice
hal_weaver_hwservice
hal_wifi_hwservice
hal_wifi_offload_hwservice
hal_wifi_supplicant_hwservice
hidl_base_hwservice
system_net_netd_hwservice
thermalcallback_hwservice
}:hwservice_manager find;
# HwBinder services offered by core components (as opposed to vendor components)
# are considered somewhat safer due to point #2 above.
neverallow all_untrusted_apps {
coredomain_hwservice
-same_process_hwservice
-hidl_allocator_hwservice # Designed for use by any domain
-hidl_manager_hwservice # Designed for use by any domain
-hidl_memory_hwservice # Designed for use by any domain
-hidl_token_hwservice # Designed for use by any domain
}:hwservice_manager find;
# SELinux is not an API for untrusted apps to use
neverallow all_untrusted_apps selinuxfs:file no_rw_file_perms;
# Restrict *Binder access from apps to HAL domains. We can only do this on full
# Treble devices where *Binder communications between apps and HALs are tightly
# restricted.
full_treble_only(`
neverallow all_untrusted_apps {
halserverdomain
-coredomain
-hal_configstore_server
-hal_graphics_allocator_server
-hal_cas_server
-hal_neuralnetworks_server
-binder_in_vendor_violators # TODO(b/35870313): Remove once all violations are gone
-untrusted_app_visible_halserver
}:binder { call transfer };
')