blob: 43890e4e897313229e47d177764ecfdc3284ca2f [file] [log] [blame]
# Rules for all domains.
# Allow reaping by init.
allow domain init:process sigchld;
# Intra-domain accesses.
allow domain self:process {
fork
sigchld
sigkill
sigstop
signull
signal
getsched
setsched
getsession
getpgid
setpgid
getcap
setcap
getattr
setrlimit
};
allow domain self:fd use;
allow domain proc:dir r_dir_perms;
allow domain proc_net:dir search;
r_dir_file(domain, self)
allow domain self:{ fifo_file file } rw_file_perms;
allow domain self:unix_dgram_socket { create_socket_perms sendto };
allow domain self:unix_stream_socket { create_stream_socket_perms connectto };
# Inherit or receive open files from others.
allow domain init:fd use;
userdebug_or_eng(`
allow domain su:fd use;
allow domain su:unix_stream_socket { connectto getattr getopt read write shutdown };
allow domain su:unix_dgram_socket sendto;
allow { domain -init } su:binder { call transfer };
# Running something like "pm dump com.android.bluetooth" requires
# fifo writes
allow domain su:fifo_file { write getattr };
# allow "gdbserver --attach" to work for su.
allow domain su:process sigchld;
# Allow writing coredumps to /cores/*
allow domain coredump_file:file create_file_perms;
allow domain coredump_file:dir ra_dir_perms;
')
# Root fs.
allow domain rootfs:dir search;
allow domain rootfs:lnk_file { read getattr };
# Device accesses.
allow domain device:dir search;
allow domain dev_type:lnk_file r_file_perms;
allow domain devpts:dir search;
allow domain socket_device:dir r_dir_perms;
allow domain owntty_device:chr_file rw_file_perms;
allow domain null_device:chr_file rw_file_perms;
allow domain zero_device:chr_file rw_file_perms;
allow domain ashmem_device:chr_file rw_file_perms;
# /dev/binder can be accessed by non-vendor domains and by apps
allow {
coredomain
appdomain
binder_in_vendor_violators # TODO(b/35870313): Remove once all violations are gone
-hwservicemanager
} binder_device:chr_file rw_file_perms;
# Devices which are not full TREBLE have fewer restrictions on access to /dev/binder
not_full_treble(`allow { domain -hwservicemanager -vndservicemanager } binder_device:chr_file rw_file_perms;')
allow { domain -servicemanager -vndservicemanager -isolated_app } hwbinder_device:chr_file rw_file_perms;
allow domain ptmx_device:chr_file rw_file_perms;
allow domain alarm_device:chr_file r_file_perms;
allow domain random_device:chr_file rw_file_perms;
allow domain proc_random:dir r_dir_perms;
allow domain proc_random:file r_file_perms;
allow domain properties_device:dir { search getattr };
allow domain properties_serial:file r_file_perms;
allow domain property_info:file r_file_perms;
# For now, everyone can access core property files
# Device specific properties are not granted by default
not_compatible_property(`
get_prop(domain, core_property_type)
get_prop(domain, exported_dalvik_prop)
get_prop(domain, exported_ffs_prop)
get_prop(domain, exported_system_radio_prop)
get_prop(domain, exported2_config_prop)
get_prop(domain, exported2_radio_prop)
get_prop(domain, exported2_system_prop)
get_prop(domain, exported2_vold_prop)
get_prop(domain, exported3_default_prop)
get_prop(domain, exported3_radio_prop)
get_prop(domain, exported3_system_prop)
get_prop(domain, vendor_default_prop)
')
compatible_property_only(`
get_prop({coredomain appdomain shell}, core_property_type)
get_prop({coredomain appdomain shell}, exported_dalvik_prop)
get_prop({coredomain appdomain shell}, exported_ffs_prop)
get_prop({coredomain appdomain shell}, exported_system_radio_prop)
get_prop({coredomain appdomain shell}, exported2_config_prop)
get_prop({coredomain appdomain shell}, exported2_radio_prop)
get_prop({coredomain appdomain shell}, exported2_system_prop)
get_prop({coredomain appdomain shell}, exported2_vold_prop)
get_prop({coredomain appdomain shell}, exported3_default_prop)
get_prop({coredomain appdomain shell}, exported3_radio_prop)
get_prop({coredomain appdomain shell}, exported3_system_prop)
userdebug_or_eng(`
get_prop(su, core_property_type)
get_prop(su, exported_dalvik_prop)
get_prop(su, exported_ffs_prop)
get_prop(su, exported_system_radio_prop)
get_prop(su, exported2_config_prop)
get_prop(su, exported2_radio_prop)
get_prop(su, exported2_system_prop)
get_prop(su, exported2_vold_prop)
get_prop(su, exported3_default_prop)
get_prop(su, exported3_radio_prop)
get_prop(su, exported3_system_prop)
')
get_prop({domain -coredomain -appdomain}, vendor_default_prop)
')
# Public readable properties
get_prop(domain, debug_prop)
get_prop(domain, exported_config_prop)
get_prop(domain, exported_default_prop)
get_prop(domain, exported_dumpstate_prop)
get_prop(domain, exported_fingerprint_prop)
get_prop(domain, exported_radio_prop)
get_prop(domain, exported_secure_prop)
get_prop(domain, exported_system_prop)
get_prop(domain, exported_vold_prop)
get_prop(domain, exported2_default_prop)
get_prop(domain, logd_prop)
# Let everyone read log properties, so that liblog can avoid sending unloggable
# messages to logd.
get_prop(domain, log_property_type)
dontaudit domain property_type:file audit_access;
allow domain property_contexts_file:file r_file_perms;
allow domain init:key search;
allow domain vold:key search;
# logd access
write_logd(domain)
# System file accesses.
allow domain system_file:dir { search getattr };
allow domain system_file:file { execute read open getattr map };
allow domain system_file:lnk_file { getattr read };
# Make sure system/vendor split doesn not affect non-treble
# devices
not_full_treble(`
allow domain vendor_file_type:dir { search getattr };
allow domain vendor_file_type:file { execute read open getattr map };
allow domain vendor_file_type:lnk_file { getattr read };
')
# All domains are allowed to open and read directories
# that contain HAL implementations (e.g. passthrough
# HALs require clients to have these permissions)
allow domain vendor_hal_file:dir r_dir_perms;
# Everyone can read and execute all same process HALs
allow domain same_process_hal_file:dir r_dir_perms;
allow domain same_process_hal_file:file { execute read open getattr map };
# Any process can load vndk-sp libraries, which are system libraries
# used by same process HALs
allow domain vndk_sp_file:dir r_dir_perms;
allow domain vndk_sp_file:file { execute read open getattr map };
# All domains get access to /vendor/etc
allow domain vendor_configs_file:dir r_dir_perms;
allow domain vendor_configs_file:file { read open getattr };
full_treble_only(`
# Allow all domains to be able to follow /system/vendor and/or
# /vendor/odm symlinks.
allow domain vendor_file_type:lnk_file { getattr open read };
# This is required to be able to search & read /vendor/lib64
# in order to lookup vendor libraries. The execute permission
# for coredomains is granted *only* for same process HALs
allow domain vendor_file:dir { getattr search };
# Allow reading and executing out of /vendor to all vendor domains
allow { domain -coredomain } vendor_file_type:dir r_dir_perms;
allow { domain -coredomain } vendor_file_type:file { read open getattr execute map };
allow { domain -coredomain } vendor_file_type:lnk_file { getattr read };
')
# read and stat any sysfs symlinks
allow domain sysfs:lnk_file { getattr read };
# libc references /data/misc/zoneinfo for timezone related information
# This directory is considered to be a VNDK-stable
allow domain zoneinfo_data_file:file r_file_perms;
allow domain zoneinfo_data_file:dir r_dir_perms;
# Lots of processes access current CPU information
r_dir_file(domain, sysfs_devices_system_cpu)
r_dir_file(domain, sysfs_usb);
# files under /data.
not_full_treble(`
allow domain system_data_file:dir getattr;
')
allow { coredomain appdomain } system_data_file:dir getattr;
# /data has the label system_data_file. Vendor components need the search
# permission on system_data_file for path traversal to /data/vendor.
allow domain system_data_file:dir search;
# TODO restrict this to non-coredomain
allow domain vendor_data_file:dir { getattr search };
# required by the dynamic linker
allow domain proc:lnk_file { getattr read };
# /proc/cpuinfo
allow domain proc_cpuinfo:file r_file_perms;
# jemalloc needs to read /proc/sys/vm/overcommit_memory
allow domain proc_overcommit_memory:file r_file_perms;
# profiling needs to read /proc/sys/kernel/perf_event_max_sample_rate
allow domain proc_perf:file r_file_perms;
# toybox loads libselinux which stats /sys/fs/selinux/
allow domain selinuxfs:dir search;
allow domain selinuxfs:file getattr;
allow domain sysfs:dir search;
allow domain selinuxfs:filesystem getattr;
# For /acct/uid/*/tasks.
allow domain cgroup:dir { search write };
allow domain cgroup:file w_file_perms;
# Almost all processes log tracing information to
# /sys/kernel/debug/tracing/trace_marker
# The reason behind this is documented in b/6513400
allow domain debugfs:dir search;
allow domain debugfs_tracing:dir search;
allow domain debugfs_tracing_debug:dir search;
allow domain debugfs_trace_marker:file w_file_perms;
# Filesystem access.
allow domain fs_type:filesystem getattr;
allow domain fs_type:dir getattr;
# Restrict all domains to a whitelist for common socket types. Additional
# ioctl commands may be added to individual domains, but this sets safe
# defaults for all processes. Note that granting this whitelist to domain does
# not grant the ioctl permission on these socket types. That must be granted
# separately.
allowxperm domain domain:{ rawip_socket tcp_socket udp_socket }
ioctl { unpriv_sock_ioctls unpriv_tty_ioctls };
# default whitelist for unix sockets.
allowxperm domain domain:{ unix_dgram_socket unix_stream_socket }
ioctl unpriv_unix_sock_ioctls;
# Restrict PTYs to only whitelisted ioctls.
# Note that granting this whitelist to domain does
# not grant the wider ioctl permission. That must be granted
# separately.
allowxperm domain devpts:chr_file ioctl unpriv_tty_ioctls;
# Workaround for policy compiler being too aggressive and removing hwservice_manager_type
# when it's not explicitly used in allow rules
allow { domain -domain } hwservice_manager_type:hwservice_manager { add find };
# Workaround for policy compiler being too aggressive and removing vndservice_manager_type
# when it's not explicitly used in allow rules
allow { domain -domain } vndservice_manager_type:service_manager { add find };
# Under ASAN, processes will try to read /data, as the sanitized libraries are there.
with_asan(`allow domain system_data_file:dir getattr;')
###
### neverallow rules
###
# All socket ioctls must be restricted to a whitelist.
neverallowxperm domain domain:socket_class_set ioctl { 0 };
# b/68014825 and https://android-review.googlesource.com/516535
# rfc6093 says that processes should not use the TCP urgent mechanism
neverallowxperm domain domain:socket_class_set ioctl { SIOCATMARK };
# TIOCSTI is only ever used for exploits. Block it.
# b/33073072, b/7530569
# http://www.openwall.com/lists/oss-security/2016/09/26/14
neverallowxperm * devpts:chr_file ioctl TIOCSTI;
# Do not allow any domain other than init to create unlabeled files.
neverallow { domain -init -recovery } unlabeled:dir_file_class_set create;
# Limit device node creation to these whitelisted domains.
neverallow {
domain
-kernel
-init
-ueventd
-vold
} self:global_capability_class_set mknod;
# Limit raw I/O to these whitelisted domains. Do not apply to debug builds.
neverallow {
domain
userdebug_or_eng(`-domain')
-kernel
-init
-recovery
-ueventd
-healthd
-uncrypt
-tee
} self:global_capability_class_set sys_rawio;
# No process can map low memory (< CONFIG_LSM_MMAP_MIN_ADDR).
neverallow * self:memprotect mmap_zero;
# No domain needs mac_override as it is unused by SELinux.
neverallow * self:global_capability2_class_set mac_override;
# Disallow attempts to set contexts not defined in current policy
# This helps guarantee that unknown or dangerous contents will not ever
# be set.
neverallow * self:global_capability2_class_set mac_admin;
# Once the policy has been loaded there shall be none to modify the policy.
# It is sealed.
neverallow * kernel:security load_policy;
# Only init prior to switching context should be able to set enforcing mode.
# init starts in kernel domain and switches to init domain via setcon in
# the init.rc, so the setenforce occurs while still in kernel. After
# switching domains, there is never any need to setenforce again by init.
neverallow * kernel:security setenforce;
neverallow { domain -kernel } kernel:security setcheckreqprot;
# No booleans in AOSP policy, so no need to ever set them.
neverallow * kernel:security setbool;
# Adjusting the AVC cache threshold.
# Not presently allowed to anything in policy, but possibly something
# that could be set from init.rc.
neverallow { domain -init } kernel:security setsecparam;
# Only init, ueventd, shell and system_server should be able to access HW RNG
neverallow {
domain
-init
-shell # For CTS and is restricted to getattr in shell.te
-system_server
-ueventd
} hw_random_device:chr_file *;
# b/78174219 b/64114943
neverallow {
domain
-init
-shell # stat of /dev, getattr only
-vendor_init
-ueventd
} keychord_device:chr_file *;
# Ensure that all entrypoint executables are in exec_type or postinstall_file.
neverallow * { file_type -exec_type -postinstall_file }:file entrypoint;
# Ensure that nothing in userspace can access /dev/mem or /dev/kmem
neverallow {
domain
-shell # For CTS and is restricted to getattr in shell.te
-ueventd # Further restricted in ueventd.te
} kmem_device:chr_file *;
neverallow * kmem_device:chr_file ~{ create relabelto unlink setattr getattr };
#Ensure that nothing in userspace can access /dev/port
neverallow {
domain
-shell # Shell user should not have any abilities outside of getattr
-ueventd
} port_device:chr_file *;
neverallow * port_device:chr_file ~{ create relabelto unlink setattr getattr };
# Only init should be able to configure kernel usermodehelpers or
# security-sensitive proc settings.
neverallow { domain -init } usermodehelper:file { append write };
neverallow { domain -init -ueventd } sysfs_usermodehelper:file { append write };
neverallow { domain -init -vendor_init } proc_security:file { append open read write };
# No domain should be allowed to ptrace init.
neverallow * init:process ptrace;
# Init can't do anything with binder calls. If this neverallow rule is being
# triggered, it's probably due to a service with no SELinux domain.
neverallow * init:binder *;
neverallow * vendor_init:binder *;
# Don't allow raw read/write/open access to block_device
# Rather force a relabel to a more specific type
neverallow { domain -kernel -init -recovery } block_device:blk_file { open read write };
# Do not allow renaming of block files or character files
# Ability to do so can lead to possible use in an exploit chain
# e.g. https://googleprojectzero.blogspot.com/2016/12/chrome-os-exploit-one-byte-overflow-and.html
neverallow * *:{ blk_file chr_file } rename;
# Don't allow raw read/write/open access to generic devices.
# Rather force a relabel to a more specific type.
neverallow domain device:chr_file { open read write };
# Limit what domains can mount filesystems or change their mount flags.
# sdcard_type / vfat is exempt as a larger set of domains need
# this capability, including device-specific domains.
neverallow { domain -kernel -init -recovery -vold -zygote -update_engine -otapreopt_chroot } { fs_type -sdcard_type }:filesystem { mount remount relabelfrom relabelto };
#
# Assert that, to the extent possible, we're not loading executable content from
# outside the rootfs or /system partition except for a few whitelisted domains.
#
neverallow {
domain
-appdomain
with_asan(`-asan_extract')
-dumpstate
-shell
userdebug_or_eng(`-su')
-webview_zygote
-zygote
userdebug_or_eng(`-mediaextractor')
} {
file_type
-system_file
-vendor_file_type
-exec_type
-postinstall_file
}:file execute;
neverallow {
domain
-appdomain # for oemfs
-bootanim # for oemfs
-recovery # for /tmp/update_binary in tmpfs
} { fs_type -rootfs }:file execute;
# Files from cache should never be executed
neverallow domain { cache_file cache_backup_file cache_private_backup_file cache_recovery_file }:file execute;
# Protect most domains from executing arbitrary content from /data.
neverallow {
domain
-appdomain
} {
data_file_type
-dalvikcache_data_file
-system_data_file # shared libs in apks
-apk_data_file
}:file no_x_file_perms;
# The test files and executables MUST not be accessible to any domain
neverallow domain nativetest_data_file:file_class_set no_w_file_perms;
neverallow domain nativetest_data_file:dir no_w_dir_perms;
neverallow { domain userdebug_or_eng(`-shell') } nativetest_data_file:file no_x_file_perms;
# Only the init property service should write to /data/property and /dev/__properties__
neverallow { domain -init } property_data_file:dir no_w_dir_perms;
neverallow { domain -init } property_data_file:file { no_w_file_perms no_x_file_perms };
neverallow { domain -init } property_type:file { no_w_file_perms no_x_file_perms };
neverallow { domain -init } properties_device:file { no_w_file_perms no_x_file_perms };
neverallow { domain -init } properties_serial:file { no_w_file_perms no_x_file_perms };
# Nobody should be doing writes to /system & /vendor
# These partitions are intended to be read-only and must never be
# modified. Doing so would violate important Android security guarantees
# and invalidate dm-verity signatures.
neverallow {
domain
with_asan(`-asan_extract')
} {
system_file
vendor_file_type
exec_type
}:dir_file_class_set { create write setattr relabelfrom append unlink link rename };
neverallow { domain -kernel with_asan(`-asan_extract') } { system_file vendor_file_type exec_type }:dir_file_class_set relabelto;
# Don't allow mounting on top of /system files or directories
neverallow * exec_type:dir_file_class_set mounton;
neverallow { domain -init } { system_file vendor_file_type }:dir_file_class_set mounton;
# Nothing should be writing to files in the rootfs.
neverallow * rootfs:file { create write setattr relabelto append unlink link rename };
# Restrict context mounts to specific types marked with
# the contextmount_type attribute.
neverallow * {fs_type -contextmount_type}:filesystem relabelto;
# Ensure that context mount types are not writable, to ensure that
# the write to /system restriction above is not bypassed via context=
# mount to another type.
neverallow * contextmount_type:dir_file_class_set
{ create write setattr relabelfrom relabelto append unlink link rename };
# Do not allow service_manager add for default service labels.
# Instead domains should use a more specific type such as
# system_app_service rather than the generic type.
# New service_types are defined in {,hw,vnd}service.te and new mappings
# from service name to service_type are defined in {,hw,vnd}service_contexts.
neverallow * default_android_service:service_manager add;
neverallow * default_android_vndservice:service_manager { add find };
neverallow * default_android_hwservice:hwservice_manager { add find };
# Looking up the base class/interface of all HwBinder services is a bad idea.
# hwservicemanager currently offer such lookups only to make it so that security
# decisions are expressed in SELinux policy. However, it's unclear whether this
# lookup has security implications. If it doesn't, hwservicemanager should be
# modified to not offer this lookup.
# This rule can be removed if hwservicemanager is modified to not permit these
# lookups.
neverallow * hidl_base_hwservice:hwservice_manager find;
# Require that domains explicitly label unknown properties, and do not allow
# anyone but init to modify unknown properties.
neverallow { domain -init -vendor_init } default_prop:property_service set;
neverallow { domain -init -vendor_init } mmc_prop:property_service set;
compatible_property_only(`
neverallow { domain -init } default_prop:property_service set;
neverallow { domain -init } mmc_prop:property_service set;
neverallow { domain -init -vendor_init } exported_default_prop:property_service set;
neverallow { domain -init } exported_secure_prop:property_service set;
neverallow { domain -init } exported2_default_prop:property_service set;
neverallow { domain -init -vendor_init } exported3_default_prop:property_service set;
neverallow { domain -init -vendor_init } vendor_default_prop:property_service set;
')
# Only core domains are allowed to access package_manager properties
neverallow { domain -init -system_server } pm_prop:property_service set;
neverallow { domain -coredomain } pm_prop:file no_rw_file_perms;
compatible_property_only(`
neverallow { domain -init -system_server -vendor_init } exported_pm_prop:property_service set;
neverallow { domain -coredomain -vendor_init } exported_pm_prop:file no_rw_file_perms;
')
# Do not allow reading device's serial number from system properties except form
# a few whitelisted domains.
neverallow {
domain
-adbd
-dumpstate
-hal_drm_server
-hal_cas_server
-init
-mediadrmserver
-recovery
-shell
-system_server
-vendor_init
} serialno_prop:file r_file_perms;
# Do not allow reading the last boot timestamp from system properties
neverallow { domain -init -system_server -dumpstate } firstboot_prop:file r_file_perms;
neverallow {
domain
-init
-recovery
-system_server
-shell # Shell is further restricted in shell.te
-ueventd # Further restricted in ueventd.te
} frp_block_device:blk_file no_rw_file_perms;
# The metadata block device is set aside for device encryption and
# verified boot metadata. It may be reset at will and should not
# be used by other domains.
neverallow {
domain
-init
-recovery
-vold
-e2fs
-fsck
} metadata_block_device:blk_file { append link rename write open read ioctl lock };
# No domain other than recovery and update_engine can write to system partition(s).
neverallow { domain -recovery -update_engine } system_block_device:blk_file { write append };
# No domains other than install_recovery or recovery can write to recovery.
neverallow { domain -install_recovery -recovery } recovery_block_device:blk_file { write append };
# No domains other than a select few can access the misc_block_device. This
# block device is reserved for OTA use.
# Do not assert this rule on userdebug/eng builds, due to some devices using
# this partition for testing purposes.
neverallow {
domain
userdebug_or_eng(`-domain') # exclude debuggable builds
-hal_bootctl_server
-init
-uncrypt
-update_engine
-vendor_init
-vold
-recovery
-ueventd
} misc_block_device:blk_file { append link relabelfrom rename write open read ioctl lock };
# Only (hw|vnd|)servicemanager should be able to register with binder as the context manager
neverallow { domain -servicemanager -hwservicemanager -vndservicemanager } *:binder set_context_mgr;
# The service managers are only allowed to access their own device node
neverallow servicemanager hwbinder_device:chr_file no_rw_file_perms;
neverallow servicemanager vndbinder_device:chr_file no_rw_file_perms;
neverallow hwservicemanager binder_device:chr_file no_rw_file_perms;
neverallow hwservicemanager vndbinder_device:chr_file no_rw_file_perms;
neverallow vndservicemanager binder_device:chr_file no_rw_file_perms;
neverallow vndservicemanager hwbinder_device:chr_file no_rw_file_perms;
# On full TREBLE devices, only core components and apps can use Binder and servicemanager. Non-core
# domain apps need this because Android framework offers many of its services to apps as Binder
# services.
full_treble_only(`
neverallow {
domain
-coredomain
-appdomain
-binder_in_vendor_violators # TODO(b/35870313): Remove once all violations are gone
} binder_device:chr_file rw_file_perms;
')
full_treble_only(`
neverallow {
domain
-coredomain
-appdomain # restrictions for vendor apps are declared lower down
-binder_in_vendor_violators # TODO(b/35870313): Remove once all violations are gone
} service_manager_type:service_manager find;
')
full_treble_only(`
# Vendor apps are permited to use only stable public services. If they were to use arbitrary
# services which can change any time framework/core is updated, breakage is likely.
neverallow {
appdomain
-coredomain
} {
service_manager_type
-app_api_service
-ephemeral_app_api_service
-audioserver_service # TODO(b/36783122) remove exemptions below once app_api_service is fixed
-cameraserver_service
-drmserver_service
-keystore_service
-mediadrmserver_service
-mediaextractor_service
-mediametrics_service
-mediaserver_service
-nfc_service
-radio_service
-virtual_touchpad_service
-vr_hwc_service
-vr_manager_service
}:service_manager find;
')
full_treble_only(`
neverallow {
domain
-coredomain
-appdomain
-binder_in_vendor_violators # TODO(b/35870313): Remove once all violations are gone
} servicemanager:binder { call transfer };
')
# On full TREBLE devices, only vendor components, shell, and su can use VendorBinder.
full_treble_only(`
neverallow {
coredomain
-shell
userdebug_or_eng(`-su')
-ueventd # uevent is granted create for this device, but we still neverallow I/O below
} vndbinder_device:chr_file rw_file_perms;
')
full_treble_only(`
neverallow ueventd vndbinder_device:chr_file { read write append ioctl };
')
full_treble_only(`
neverallow {
coredomain
-shell
userdebug_or_eng(`-su')
} vndservice_manager_type:service_manager *;
')
full_treble_only(`
neverallow {
coredomain
-shell
userdebug_or_eng(`-su')
} vndservicemanager:binder *;
')
# On full TREBLE devices, socket communications between core components and vendor components are
# not permitted.
# Most general rules first, more specific rules below.
# Core domains are not permitted to initiate communications to vendor domain sockets.
# We are not restricting the use of already established sockets because it is fine for a process
# to obtain an already established socket via some public/official/stable API and then exchange
# data with its peer over that socket. The wire format in this scenario is dicatated by the API
# and thus does not break the core-vendor separation.
full_treble_only(`
neverallow_establish_socket_comms({
coredomain
-init
-adbd
}, {
domain
-coredomain
-socket_between_core_and_vendor_violators
});
')
# Vendor domains are not permitted to initiate communications to core domain sockets
full_treble_only(`
neverallow_establish_socket_comms({
domain
-coredomain
-appdomain
-socket_between_core_and_vendor_violators
}, {
coredomain
-logd # Logging by writing to logd Unix domain socket is public API
-netd # netdomain needs this
-mdnsd # netdomain needs this
userdebug_or_eng(`-su') # communications with su are permitted only on userdebug or eng builds
-init
-incidentd # TODO(b/35870313): Remove incidentd from this list once vendor domains no longer declare Binder services
-tombstoned # TODO(b/36604251): Remove tombstoned from this list once mediacodec (OMX HAL) no longer declares Binder services
});
')
# Vendor domains (except netdomain) are not permitted to initiate communications to netd sockets
full_treble_only(`
neverallow_establish_socket_comms({
domain
-coredomain
-netdomain
-socket_between_core_and_vendor_violators
}, netd);
')
# Vendor domains are not permitted to initiate create/open sockets owned by core domains
full_treble_only(`
neverallow {
domain
-coredomain
-appdomain # appdomain restrictions below
-data_between_core_and_vendor_violators # b/70393317
-socket_between_core_and_vendor_violators
-vendor_init
} {
coredomain_socket
core_data_file_type
unlabeled # used only by core domains
}:sock_file ~{ append getattr ioctl read write };
')
full_treble_only(`
neverallow {
appdomain
-coredomain
} {
coredomain_socket
unlabeled # used only by core domains
core_data_file_type
-app_data_file
-pdx_endpoint_socket_type # used by VR layer
-pdx_channel_socket_type # used by VR layer
}:sock_file ~{ append getattr ioctl read write };
')
# Core domains are not permitted to create/open sockets owned by vendor domains
full_treble_only(`
neverallow {
coredomain
-init
-ueventd
-socket_between_core_and_vendor_violators
} {
file_type
dev_type
-coredomain_socket
-core_data_file_type
-unlabeled
}:sock_file ~{ append getattr ioctl read write };
')
# On TREBLE devices, vendor and system components are only allowed to share
# files by passing open FDs over hwbinder. Ban all directory access and all file
# accesses other than what can be applied to an open FD such as
# ioctl/stat/read/write/append. This is enforced by segregating /data.
# Vendor domains may directly access file in /data/vendor by path, but may only
# access files outside of /data/vendor via an open FD passed over hwbinder.
# Likewise, core domains may only directly access files outside /data/vendor by
# path and files in /data/vendor by open FD.
full_treble_only(`
# only coredomains may only access core_data_file_type, particularly not
# /data/vendor
neverallow {
coredomain
-appdomain # TODO(b/34980020) remove exemption for appdomain
-data_between_core_and_vendor_violators
-init
} {
data_file_type
-core_data_file_type
}:file_class_set ~{ append getattr ioctl read write };
')
full_treble_only(`
neverallow {
coredomain
-appdomain # TODO(b/34980020) remove exemption for appdomain
-data_between_core_and_vendor_violators
-init
} {
data_file_type
-core_data_file_type
# TODO(b/72998741) Remove exemption. Further restricted in a subsequent
# neverallow. Currently only getattr and search are allowed.
-vendor_data_file
}:dir *;
')
full_treble_only(`
# vendor domains may only access files in /data/vendor, never core_data_file_types
neverallow {
domain
-appdomain # TODO(b/34980020) remove exemption for appdomain
-coredomain
-data_between_core_and_vendor_violators # TODO(b/34980020) Remove once all violators have been cleaned up
-vendor_init
} {
core_data_file_type
# libc includes functions like mktime and localtime which attempt to access
# files in /data/misc/zoneinfo/tzdata file. These functions are considered
# vndk-stable and thus must be allowed for all processes.
-zoneinfo_data_file
}:file_class_set ~{ append getattr ioctl read write };
neverallow {
vendor_init
-data_between_core_and_vendor_violators
} {
core_data_file_type
-unencrypted_data_file
-zoneinfo_data_file
}:file_class_set ~{ append getattr ioctl read write };
# vendor init needs to be able to read unencrypted_data_file to create directories with FBE.
# The vendor init binary lives on the system partition so there is not a concern with stability.
neverallow vendor_init unencrypted_data_file:file ~r_file_perms;
')
full_treble_only(`
# vendor domains may only access dirs in /data/vendor, never core_data_file_types
neverallow {
domain
-appdomain # TODO(b/34980020) remove exemption for appdomain
-coredomain
-data_between_core_and_vendor_violators
-vendor_init
} {
core_data_file_type
-system_data_file # default label for files on /data. Covered below...
-vendor_data_file
-zoneinfo_data_file
}:dir *;
neverallow {
vendor_init
-data_between_core_and_vendor_violators
} {
core_data_file_type
-unencrypted_data_file
-system_data_file
-vendor_data_file
-zoneinfo_data_file
}:dir *;
# vendor init needs to be able to read unencrypted_data_file to create directories with FBE.
# The vendor init binary lives on the system partition so there is not a concern with stability.
neverallow vendor_init unencrypted_data_file:dir ~search;
')
full_treble_only(`
# vendor domains may only access dirs in /data/vendor, never core_data_file_types
neverallow {
domain
-appdomain # TODO(b/34980020) remove exemption for appdomain
-coredomain
-data_between_core_and_vendor_violators # TODO(b/34980020) Remove once all violators have been cleaned up
} {
system_data_file # default label for files on /data. Covered below
}:dir ~{ getattr search };
')
full_treble_only(`
# coredomains may not access dirs in /data/vendor.
neverallow {
coredomain
-data_between_core_and_vendor_violators # TODO(b/34980020) Remove once all violators have been cleaned up
-init
-vold # vold creates per-user storage for both system and vendor
-vold_prepare_subdirs
} {
vendor_data_file # default label for files on /data. Covered below
}:dir ~{ getattr search };
')
full_treble_only(`
# coredomains may not access dirs in /data/vendor.
neverallow {
coredomain
-data_between_core_and_vendor_violators # TODO(b/34980020) Remove once all violators have been cleaned up
-init
} {
vendor_data_file # default label for files on /data/vendor{,_ce,_de}.
}:file_class_set ~{ append getattr ioctl read write };
')
# On TREBLE devices, a limited set of files in /vendor are accessible to
# only a few whitelisted coredomains to keep system/vendor separation.
full_treble_only(`
# Limit access to /vendor/app
neverallow {
coredomain
-appdomain
-dex2oat
-idmap
-init
-installd
userdebug_or_eng(`-perfprofd')
-postinstall_dexopt
-system_server
} vendor_app_file:dir { open read getattr search };
')
full_treble_only(`
neverallow {
coredomain
-appdomain
-dex2oat
-idmap
-init
-installd
userdebug_or_eng(`-perfprofd')
-postinstall_dexopt
-system_server
-mediaserver
} vendor_app_file:file r_file_perms;
')
full_treble_only(`
# Limit access to /vendor/overlay
neverallow {
coredomain
-appdomain
-idmap
-init
-installd
-system_server
-webview_zygote
-zygote
} vendor_overlay_file:dir { getattr open read search };
')
full_treble_only(`
neverallow {
coredomain
-appdomain
-idmap
-init
-installd
-system_server
-webview_zygote
-zygote
} vendor_overlay_file:file r_file_perms;
')
full_treble_only(`
# Non-vendor domains are not allowed to file execute shell
# from vendor
neverallow {
coredomain
-init
-shell
} vendor_shell_exec:file { execute execute_no_trans };
')
full_treble_only(`
# Do not allow vendor components to execute files from system
# except for the ones whitelist here.
neverallow {
domain
-coredomain
-appdomain
-vendor_executes_system_violators
-vendor_init
} {
exec_type
-vendor_file_type
-crash_dump_exec
-netutils_wrapper_exec
}:file { entrypoint execute execute_no_trans };
')
full_treble_only(`
# Do not allow system components to execute files from vendor
# except for the ones whitelisted here.
neverallow {
coredomain
-init
-shell
-system_executes_vendor_violators
} {
vendor_file_type
-same_process_hal_file
-vndk_sp_file
-vendor_app_file
-vendor_public_lib_file
}:file execute;
')
full_treble_only(`
neverallow {
coredomain
-shell
-system_executes_vendor_violators
} vendor_file_type:file execute_no_trans;
')
# Only authorized processes should be writing to files in /data/dalvik-cache
neverallow {
domain
-init # TODO: limit init to relabelfrom for files
-zygote
-installd
-postinstall_dexopt
-cppreopts
-dex2oat
-otapreopt_slot
} dalvikcache_data_file:file no_w_file_perms;
neverallow {
domain
-init
-installd
-postinstall_dexopt
-cppreopts
-dex2oat
-zygote
-otapreopt_slot
} dalvikcache_data_file:dir no_w_dir_perms;
# Only system_server should be able to send commands via the zygote socket
neverallow { domain -zygote -system_server } zygote:unix_stream_socket connectto;
neverallow { domain -system_server } zygote_socket:sock_file write;
neverallow { domain -system_server -webview_zygote } webview_zygote:unix_stream_socket connectto;
neverallow { domain -system_server } webview_zygote:sock_file write;
neverallow {
domain
-tombstoned
-crash_dump
-dumpstate
-incidentd
-system_server
# Processes that can't exec crash_dump
-mediacodec
-mediaextractor
} tombstoned_crash_socket:unix_stream_socket connectto;
# Never allow anyone except dumpstate, incidentd, or the system server to connect or write to
# the tombstoned intercept socket.
neverallow { domain -dumpstate -incidentd -system_server } tombstoned_intercept_socket:sock_file write;
neverallow { domain -dumpstate -incidentd -system_server } tombstoned_intercept_socket:unix_stream_socket connectto;
# Android does not support System V IPCs.
#
# The reason for this is due to the fact that, by design, they lead to global
# kernel resource leakage.
#
# For example, there is no way to automatically release a SysV semaphore
# allocated in the kernel when:
#
# - a buggy or malicious process exits
# - a non-buggy and non-malicious process crashes or is explicitly killed.
#
# Killing processes automatically to make room for new ones is an
# important part of Android's application lifecycle implementation. This means
# that, even assuming only non-buggy and non-malicious code, it is very likely
# that over time, the kernel global tables used to implement SysV IPCs will fill
# up.
neverallow * *:{ shm sem msg msgq } *;
# Do not mount on top of symlinks, fifos, or sockets.
# Feature parity with Chromium LSM.
neverallow * { file_type fs_type dev_type }:{ lnk_file fifo_file sock_file } mounton;
# Nobody should be able to execute su on user builds.
# On userdebug/eng builds, only dumpstate, shell, and
# su itself execute su.
neverallow { domain userdebug_or_eng(`-dumpstate -shell -su') } su_exec:file no_x_file_perms;
# Do not allow the introduction of new execmod rules. Text relocations
# and modification of executable pages are unsafe.
# The only exceptions are for NDK text relocations associated with
# https://code.google.com/p/android/issues/detail?id=23203
# which, long term, need to go away.
neverallow * {
file_type
-apk_data_file
-app_data_file
-asec_public_file
}:file execmod;
# Do not allow making the stack or heap executable.
# We would also like to minimize execmem but it seems to be
# required by some device-specific service domains.
neverallow * self:process { execstack execheap };
# prohibit non-zygote spawned processes from using shared libraries
# with text relocations. b/20013628 .
neverallow { domain -untrusted_app_all } file_type:file execmod;
neverallow { domain -init } proc:{ file dir } mounton;
# Ensure that all types assigned to processes are included
# in the domain attribute, so that all allow and neverallow rules
# written on domain are applied to all processes.
# This is achieved by ensuring that it is impossible to transition
# from a domain to a non-domain type and vice versa.
# TODO - rework this: neverallow domain ~domain:process { transition dyntransition };
neverallow ~domain domain:process { transition dyntransition };
#
# Only system_app and system_server should be creating or writing
# their files. The proper way to share files is to setup
# type transitions to a more specific type or assigning a type
# to its parent directory via a file_contexts entry.
# Example type transition:
# mydomain.te:file_type_auto_trans(mydomain, system_data_file, new_file_type)
#
neverallow {
domain
-system_server
-system_app
-init
-installd # for relabelfrom and unlink, check for this in explicit neverallow
-vold_prepare_subdirs # For unlink
with_asan(`-asan_extract')
} system_data_file:file no_w_file_perms;
# do not grant anything greater than r_file_perms and relabelfrom unlink
# to installd
neverallow installd system_data_file:file ~{ r_file_perms relabelfrom unlink };
# respect system_app sandboxes
neverallow {
domain
-appdomain # finer-grained rules for appdomain are listed below
-system_server #populate com.android.providers.settings/databases/settings.db.
-installd # creation of app sandbox
-traced_probes # resolve inodes for i/o tracing.
# only needs open and read, the rest is neverallow in
# traced_probes.te.
} system_app_data_file:dir_file_class_set { create unlink open };
neverallow {
isolated_app
untrusted_app_all # finer-grained rules for appdomain are listed below
ephemeral_app
priv_app
} system_app_data_file:dir_file_class_set { create unlink open };
# Services should respect app sandboxes
neverallow {
domain
-appdomain
-installd # creation of sandbox
} app_data_file:dir_file_class_set { create unlink };
neverallow {
domain
-init
-installd
} app_data_file:dir_file_class_set { relabelfrom relabelto };
#
# Only these domains should transition to shell domain. This domain is
# permissible for the "shell user". If you need a process to exec a shell
# script with differing privilege, define a domain and set up a transition.
#
neverallow {
domain
-adbd
-init
-runas
-zygote
} shell:process { transition dyntransition };
# Only domains spawned from zygote and runas may have the appdomain attribute.
neverallow { domain -runas -webview_zygote -zygote } {
appdomain -shell userdebug_or_eng(`-su')
}:process { transition dyntransition };
# Minimize read access to shell- or app-writable symlinks.
# This is to prevent malicious symlink attacks.
neverallow {
domain
-appdomain
-installd
-uncrypt # TODO: see if we can remove
} app_data_file:lnk_file read;
neverallow {
domain
-shell
userdebug_or_eng(`-uncrypt')
-installd
} shell_data_file:lnk_file read;
# In addition to the symlink reading restrictions above, restrict
# write access to shell owned directories. The /data/local/tmp
# directory is untrustworthy, and non-whitelisted domains should
# not be trusting any content in those directories.
neverallow {
domain
-adbd
-dumpstate
-installd
-init
-shell
-vold
} shell_data_file:dir no_w_dir_perms;
neverallow {
domain
-adbd
-appdomain
-dumpstate
-init
-installd
-system_server # why?
userdebug_or_eng(`-uncrypt')
} shell_data_file:dir { open search };
# Same as above for /data/local/tmp files. We allow shell files
# to be passed around by file descriptor, but not directly opened.
neverallow {
domain
-adbd
-appdomain
-dumpstate
-installd
userdebug_or_eng(`-uncrypt')
} shell_data_file:file open;
# servicemanager and vndservicemanager are the only processes which handle the
# service_manager list request
neverallow * ~{
servicemanager
vndservicemanager
}:service_manager list;
# hwservicemanager is the only process which handles hw list requests
neverallow * ~{
hwservicemanager
}:hwservice_manager list;
# only service_manager_types can be added to service_manager
# TODO - rework this: neverallow * ~service_manager_type:service_manager { add find };
# Prevent assigning non property types to properties
# TODO - rework this: neverallow * ~property_type:property_service set;
# Domain types should never be assigned to any files other
# than the /proc/pid files associated with a process. The
# executable file used to enter a domain should be labeled
# with its own _exec type, not with the domain type.
# Conventionally, this looks something like:
# $ cat mydaemon.te
# type mydaemon, domain;
# type mydaemon_exec, exec_type, file_type;
# init_daemon_domain(mydaemon)
# $ grep mydaemon file_contexts
# /system/bin/mydaemon -- u:object_r:mydaemon_exec:s0
neverallow * domain:file { execute execute_no_trans entrypoint };
# Do not allow access to the generic debugfs label. This is too broad.
# Instead, if access to part of debugfs is desired, it should have a
# more specific label.
# TODO: fix system_server and dumpstate
neverallow { domain -init -vendor_init -system_server -dumpstate } debugfs:file no_rw_file_perms;
# Profiles contain untrusted data and profman parses that. We should only run
# in from installd forked processes.
neverallow {
domain
-installd
-profman
} profman_exec:file no_x_file_perms;
# Enforce restrictions on kernel module origin.
# Do not allow kernel module loading except from system,
# vendor, and boot partitions.
neverallow * ~{ system_file vendor_file rootfs }:system module_load;
# Only allow filesystem caps to be set at build time. Runtime changes
# to filesystem capabilities are not permitted.
neverallow * self:global_capability_class_set setfcap;
# Enforce AT_SECURE for executing crash_dump.
neverallow domain crash_dump:process noatsecure;
# Do not permit non-core domains to register HwBinder services which are
# guaranteed to be provided by core domains only.
neverallow ~coredomain coredomain_hwservice:hwservice_manager add;
# Do not permit the registeration of HwBinder services which are guaranteed to
# be passthrough only (i.e., run in the process of their clients instead of a
# separate server process).
neverallow * same_process_hwservice:hwservice_manager add;
# On TREBLE devices, most coredomains should not access vendor_files.
# TODO(b/71553434): Remove exceptions here.
full_treble_only(`
neverallow {
coredomain
-appdomain
-bootanim
-crash_dump
-init
-kernel
-perfprofd
-ueventd
} vendor_file:file { no_w_file_perms no_x_file_perms open };
')
# Minimize dac_override and dac_read_search.
# Instead of granting them it is usually better to add the domain to
# a Unix group or change the permissions of a file.
neverallow {
domain
-dnsmasq
-dumpstate
-init
-installd
-install_recovery
-lmkd
-netd
-perfprofd
-postinstall_dexopt
-recovery
-sdcardd
-tee
-ueventd
-uncrypt
-vendor_init
-vold
-vold_prepare_subdirs
-zygote
} self:capability dac_override;
neverallow { domain -traced_probes } self:capability dac_read_search;
# If an already existing file is opened with O_CREAT, the kernel might generate
# a false report of a create denial. Silence these denials and make sure that
# inappropriate permissions are not granted.
# These filesystems don't allow files or directories to be created, so the permission
# to do so should never be granted.
neverallow domain {
proc_type
sysfs_type
}:dir { add_name create link remove_name rename reparent rmdir write };
# cgroupfs directories can be created, but not files within them.
neverallow domain cgroup:file create;
dontaudit domain proc_type:dir write;
dontaudit domain sysfs_type:dir write;
dontaudit domain cgroup:file create;
# These are only needed in permissive mode - in enforcing mode the
# directory write check fails and so these are never attempted.
userdebug_or_eng(`
dontaudit domain proc_type:dir add_name;
dontaudit domain sysfs_type:dir add_name;
dontaudit domain proc_type:file create;
dontaudit domain sysfs_type:file create;
')
# Platform must not have access to /mnt/vendor.
neverallow {
coredomain
-init
} mnt_vendor_file:dir *;
# Only apps are allowed access to vendor public libraries.
full_treble_only(`
neverallow {
coredomain
-appdomain
} vendor_public_lib_file:file { execute execute_no_trans };
')