# 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_type: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; ') with_native_coverage(` # Allow writing coverage information to /data/misc/trace allow domain method_trace_data_file:dir create_dir_perms; allow domain method_trace_data_file:file create_file_perms; ') # Root fs. allow domain tmpfs:dir { getattr search }; 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 # TODO(b/113362644): route coredomain to ashmemd #-coredomain -mediaprovider -ephemeral_app -isolated_app -untrusted_app_all } ashmem_device:chr_file rw_file_perms; # Allow using fds to /dev/ashmem. allow domain ashmemd:fd use; # /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 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; # 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) # Directory/link file access for path resolution. allow domain { system_file system_lib_file system_seccomp_policy_file system_security_cacerts_file }:dir r_dir_perms; allow domain system_file:lnk_file { getattr read }; # Global access to /system/etc/security/cacerts/*, /system/etc/seccomp_policy/*, /system/lib[64]/*, # linker and its config. allow domain system_seccomp_policy_file:file r_file_perms; # cacerts are accessible from public Java API. allow domain system_security_cacerts_file:file r_file_perms; allow domain system_linker_exec:file { execute read open getattr map }; allow domain system_linker_config_file:file r_file_perms; allow domain system_lib_file:file { execute read open getattr map }; # To allow following symlinks at /system/bin/linker, /system/lib/libc.so, etc. allow domain system_linker_exec:lnk_file { read open getattr }; allow domain system_lib_file:lnk_file { read open getattr }; allow domain system_event_log_tags_file:file r_file_perms; allow { appdomain coredomain } system_file:file { execute read open getattr map }; # Make sure system/vendor split doesn not affect non-treble # devices not_full_treble(` allow domain system_file:file { execute read open getattr map }; 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 -coredomain # access is explicitly granted to individual coredomains } 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 map }; 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 and /system/usr/share/zoneinfo for # timezone related information. # This directory is considered to be a VNDK-stable allow domain { system_zoneinfo_file zoneinfo_data_file }:file r_file_perms; allow domain { system_zoneinfo_file 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); # If kernel CONFIG_TRANSPARENT_HUGEPAGE is enabled, libjemalloc5 (statically # included by libc) reads /sys/kernel/mm/transparent_hugepage/enabled. allow domain sysfs_transparent_hugepage:dir search; allow domain sysfs_transparent_hugepage:file r_file_perms; # 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; # /dev/cpu_variant:.* allow domain dev_cpu_variant: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; # 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:{ icmp_socket rawip_socket tcp_socket udp_socket } ioctl { unpriv_sock_ioctls unpriv_tty_ioctls }; # default whitelist for unix sockets. allowxperm domain { domain pdx_channel_socket_type }:{ 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; # All domains must clearly enumerate what ioctls they use # on filesystem objects (plain files, directories, symbolic links, # named pipes, and named sockets). We start off with a safe set. allowxperm domain { file_type fs_type domain dev_type }:{ dir notdevfile_class_set blk_file } ioctl { FIOCLEX FIONCLEX }; # If a domain has ioctl access to tun_device, it must clearly enumerate the # ioctls used. Safe defaults are listed below. allowxperm domain tun_device:chr_file ioctl { FIOCLEX FIONCLEX }; # Allow a process to make a determination whether a file descriptor # for a plain file or pipe (fifo_file) is a tty. Note that granting # this whitelist to domain does not grant the ioctl permission to # these files. That must be granted separately. allowxperm domain { file_type fs_type }:file ioctl { TCGETS }; allowxperm domain domain:fifo_file ioctl { TCGETS }; # If a domain has access to perform an ioctl on a block device, allow these # very common, benign ioctls allowxperm domain dev_type:blk_file ioctl { BLKGETSIZE64 BLKSSZGET }; # Support sqlite F2FS specific optimizations # ioctl permission on the specific file type is still required # TODO: consider only compiling these rules if we know the # /data partition is F2FS allowxperm domain { file_type sdcard_type }:file ioctl { F2FS_IOC_ABORT_VOLATILE_WRITE F2FS_IOC_COMMIT_ATOMIC_WRITE F2FS_IOC_GET_FEATURES F2FS_IOC_GET_PIN_FILE F2FS_IOC_SET_PIN_FILE F2FS_IOC_START_ATOMIC_WRITE }; # 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;') # Under ASAN, /system/asan.options needs to be globally accessible. with_asan(`allow domain system_asan_options_file:file r_file_perms;') # read APEX dir and stat any symlink pointing to APEXs. allow domain apex_mnt_dir:dir { getattr search }; allow domain apex_mnt_dir:lnk_file r_file_perms; ### ### neverallow rules ### # All ioctls on file-like objects (except chr_file and blk_file) and # sockets must be restricted to a whitelist. neverallowxperm * *:{ dir notdevfile_class_set socket_class_set blk_file } 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; # 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 -shell # stat of /dev, getattr only -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; # The dynamic linker always calls access(2) on the path. Don't generate SElinux # denials since the linker does not actually access the path in case the path # does not exist or isn't accessible for the process. dontaudit domain postinstall_mnt_dir:dir audit_access; #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 }; # Nobody is allowed to make binder calls into init. # Only servicemanager may transfer binder references to init # vendor_init shouldn't use binder at all. neverallow * init:binder ~{ transfer }; neverallow { domain -servicemanager } init:binder { transfer }; 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 }; # 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 userdebug_or_eng(`-kernel') } 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') recovery_only(`userdebug_or_eng(`-fastbootd')') } { system_file_type 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_type 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_type 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 setattr relabelfrom relabelto append link rename }; neverallow { domain recovery_only(`userdebug_or_eng(`-fastbootd')') } contextmount_type:dir_file_class_set { write unlink }; # 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 -fastbootd -hal_camera_server -hal_cas_server -hal_drm_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 -fastbootd } metadata_block_device:blk_file { append link rename write open read ioctl lock }; # No domain other than recovery, update_engine and fastbootd can write to system partition(s). neverallow { domain -fastbootd userdebug_or_eng(`-fsck') userdebug_or_eng(`-init') -recovery -update_engine } system_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 -fastbootd -hal_bootctl_server -init -uncrypt -update_engine -vendor_init -vendor_misc_writer -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; ') # libcutils can probe for /dev/binder permissions with access(). Ignore # generated denials. See b/129073672 for details. dontaudit domain binder_device:chr_file audit_access; 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 -tombstoned # linker to tombstoned userdebug_or_eng('-heapprofd`) }); ') # 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 -privapp_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 -vold_prepare_subdirs } { data_file_type -core_data_file_type }:file_class_set ~{ append getattr ioctl read write map }; ') full_treble_only(` neverallow { coredomain -appdomain # TODO(b/34980020) remove exemption for appdomain -data_between_core_and_vendor_violators -init -vold_prepare_subdirs } { 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 and /system/usr/share/zoneinfo/tzdata. # These functions are considered vndk-stable and thus must be allowed for # all processes. -zoneinfo_data_file with_native_coverage(`-method_trace_data_file') }:file_class_set ~{ append getattr ioctl read write map }; neverallow { vendor_init -data_between_core_and_vendor_violators } { core_data_file_type -unencrypted_data_file -zoneinfo_data_file with_native_coverage(`-method_trace_data_file') }:file_class_set ~{ append getattr ioctl read write map }; # 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 with_native_coverage(`-method_trace_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 with_native_coverage(`-method_trace_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 map }; ') 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 } { system_file_type -system_lib_file -system_linker_exec -crash_dump_exec -netutils_wrapper_exec userdebug_or_eng(`-tcpdump_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 -same_process_hal_file }:file execute_no_trans; ') full_treble_only(` # Do not allow system components access to /vendor files except for the # ones whitelisted here. neverallow { coredomain # TODO(b/37168747): clean up fwk access to /vendor -crash_dump -init # starts vendor executables -kernel # loads /vendor/firmware userdebug_or_eng(`-perfprofd') userdebug_or_eng(`-heapprofd') -shell -system_executes_vendor_violators -ueventd # reads /vendor/ueventd.rc } { vendor_file_type -same_process_hal_file -vendor_app_file -vendor_configs_file -vendor_framework_file -vendor_idc_file -vendor_keychars_file -vendor_keylayout_file -vendor_overlay_file -vendor_public_lib_file -vendor_task_profiles_file -vndk_sp_file }:file *; ') full_treble_only(` # Do not allow vendor components access to /system files except for the # ones whitelisted here. neverallow { domain -appdomain -coredomain -vendor_executes_system_violators # vendor_init needs access to init_exec for domain transition. vendor_init # neverallows are covered in public/vendor_init.te -vendor_init } { system_file_type -crash_dump_exec -file_contexts_file -netutils_wrapper_exec -property_contexts_file -system_event_log_tags_file -system_lib_file with_asan(`-system_asan_options_file') -system_linker_exec -system_linker_config_file -system_seccomp_policy_file -system_security_cacerts_file -system_zoneinfo_file -task_profiles_file userdebug_or_eng(`-tcpdump_exec') }:file *; ') # 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 -app_zygote } webview_zygote:unix_stream_socket connectto; neverallow { domain -system_server } webview_zygote:sock_file write; neverallow { domain -system_server } app_zygote:sock_file write; neverallow { domain -tombstoned -crash_dump -dumpstate -incidentd -system_server # Processes that can't exec crash_dump -hal_codec2_server -hal_omx_server -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 }; # Do not allow the introduction of new execmod rules. Text relocations # and modification of executable pages are unsafe. neverallow { domain -untrusted_app_25 -untrusted_app_27 } 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 }; # # 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, runas and simpleperf_app_runner may have the appdomain # attribute. neverallow { domain -simpleperf_app_runner -runas -app_zygote -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 } { app_data_file privapp_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 -simpleperf_app_runner -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 dumpstate neverallow { domain -init -vendor_init -dumpstate } debugfs:{ file lnk_file } no_rw_file_perms; # Do not allow executable files in debugfs. neverallow domain debugfs_type:file { execute execute_no_trans }; # 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 -heapprofd -ueventd } vendor_file:file { no_w_file_perms no_x_file_perms open }; ') # 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 -ueventd -vold -system_writes_mnt_vendor_violators } 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 }; ') # Vendor domian must not have access to /mnt/product. neverallow { domain -coredomain } mnt_product_file:dir *; # Platform must not have access to sysfs_batteryinfo, but should do it via health HAL and healthd full_treble_only(` neverallow { coredomain -healthd -shell # Generate uevents for health info -ueventd # Recovery uses health HAL passthrough implementation. -recovery # Charger uses health HAL passthrough implementation. -charger # TODO(b/110891300): remove this exception -incidentd } sysfs_batteryinfo:file { open read }; ') neverallow { domain -hal_codec2_server -hal_omx_server } hal_codec2_hwservice:hwservice_manager add;