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# Transition to crash_dump when /system/bin/crash_dump* is executed.
# This occurs when the process crashes.
# We do not apply this to the su domain to avoid interfering with
# tests (b/114136122)
domain_auto_trans({ domain userdebug_or_eng(`-su') }, crash_dump_exec, crash_dump);
allow domain crash_dump:process sigchld;
# Allow every process to check the heapprofd.enable properties to determine
# whether to load the heap profiling library. This does not necessarily enable
# heap profiling, as initialization will fail if it does not have the
# necessary SELinux permissions.
get_prop(domain, heapprofd_prop);
# Allow heap profiling on debug builds.
userdebug_or_eng(`can_profile_heap_userdebug_or_eng({
domain
-bpfloader
-init
-kernel
-keystore
-llkd
-logd
-logpersist
-recovery
-recovery_persist
-recovery_refresh
-ueventd
-vendor_init
-vold
})')
# Path resolution access in cgroups.
allow domain cgroup:dir search;
allow { domain -appdomain -rs } cgroup:dir w_dir_perms;
allow { domain -appdomain -rs } cgroup:file w_file_perms;
allow domain cgroup_rc_file:dir search;
allow domain cgroup_rc_file:file r_file_perms;
allow domain task_profiles_file:file r_file_perms;
allow domain vendor_task_profiles_file:file r_file_perms;
# Allow all domains to read sys.use_memfd to determine
# if memfd support can be used if device supports it
get_prop(domain, use_memfd_prop);
# 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)
get_prop({domain -coredomain -appdomain}, vendor_default_prop)
')
# Allow access to fsverity keyring.
allow domain kernel:key search;
# Allow access to keys in the fsverity keyring that were installed at boot.
allow domain fsverity_init:key search;
# For testing purposes, allow access to keys installed with su.
userdebug_or_eng(`
allow domain su:key search;
')
# Limit ability to ptrace or read sensitive /proc/pid files of processes
# with other UIDs to these allowlisted domains.
neverallow {
domain
-vold
userdebug_or_eng(`-llkd')
-dumpstate
userdebug_or_eng(`-incidentd')
-storaged
-system_server
userdebug_or_eng(`-perfprofd')
} self:global_capability_class_set sys_ptrace;
# Limit ability to generate hardware unique device ID attestations to priv_apps
neverallow { domain -priv_app } *:keystore_key gen_unique_id;
neverallow {
domain
-init
-vendor_init
userdebug_or_eng(`-domain')
} debugfs_tracing_debug:file no_rw_file_perms;
# System_server owns dropbox data, and init creates/restorecons the directory
# Disallow direct access by other processes.
neverallow { domain -init -system_server } dropbox_data_file:dir *;
neverallow { domain -init -system_server } dropbox_data_file:file ~{ getattr read };
###
# Services should respect app sandboxes
neverallow {
domain
-appdomain
-installd # creation of sandbox
} { privapp_data_file app_data_file }:dir_file_class_set { create unlink };
# Only the following processes should be directly accessing private app
# directories.
neverallow {
domain
-adbd
-appdomain
-app_zygote
-dexoptanalyzer
-installd
userdebug_or_eng(`-perfprofd')
-profman
-rs # spawned by appdomain, so carryover the exception above
-runas
-system_server
-viewcompiler
} { privapp_data_file app_data_file }:dir *;
# Only apps should be modifying app data. installd is exempted for
# restorecon and package install/uninstall.
neverallow {
domain
-appdomain
-installd
-rs # spawned by appdomain, so carryover the exception above
} { privapp_data_file app_data_file }:dir ~r_dir_perms;
neverallow {
domain
-appdomain
-app_zygote
-installd
userdebug_or_eng(`-perfprofd')
-rs # spawned by appdomain, so carryover the exception above
} { privapp_data_file app_data_file }:file_class_set open;
neverallow {
domain
-appdomain
-installd # creation of sandbox
} { privapp_data_file app_data_file }:dir_file_class_set { create unlink };
neverallow {
domain
-installd
} { privapp_data_file app_data_file }:dir_file_class_set { relabelfrom relabelto };
# The staging directory contains APEX and APK files. It is important to ensure
# that these files cannot be accessed by other domains to ensure that the files
# do not change between system_server staging the files and apexd processing
# the files.
neverallow { domain -init -system_server -apexd -installd} staging_data_file:dir *;
neverallow { domain -init -system_app -system_server -apexd -kernel -installd } staging_data_file:file *;
neverallow { domain -init -system_server -installd} staging_data_file:dir no_w_dir_perms;
# apexd needs the link and unlink permissions, so list every `no_w_file_perms`
# except for `link` and `unlink`.
neverallow { domain -init -system_server } staging_data_file:file
{ append create relabelfrom rename setattr write no_x_file_perms };
neverallow {
domain
-appdomain # for oemfs
-bootanim # for oemfs
-recovery # for /tmp/update_binary in tmpfs
} { fs_type -rootfs }:file execute;
#
# Assert that, to the extent possible, we're not loading executable content from
# outside the rootfs or /system partition except for a few allowlisted domains.
# Executable files loaded from /data is a persistence vector
# we want to avoid. See
# https://bugs.chromium.org/p/project-zero/issues/detail?id=955 for example.
#
neverallow {
domain
-appdomain
with_asan(`-asan_extract')
-shell
userdebug_or_eng(`-su')
-system_server_startup # for memfd backed executable regions
-app_zygote
-webview_zygote
-zygote
userdebug_or_eng(`-mediaextractor')
userdebug_or_eng(`-mediaswcodec')
} {
file_type
-system_file_type
-system_lib_file
-system_linker_exec
-vendor_file_type
-exec_type
-postinstall_file
}:file execute;
# Only init is allowed to write cgroup.rc file
neverallow {
domain
-init
-vendor_init
} cgroup_rc_file:file no_w_file_perms;
# 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
-art_apex_postinstall
-art_apex_boot_integrity
} dalvikcache_data_file:file no_w_file_perms;
neverallow {
domain
-init
-installd
-postinstall_dexopt
-cppreopts
-dex2oat
-zygote
-otapreopt_slot
-art_apex_boot_integrity
-art_apex_postinstall
} dalvikcache_data_file:dir no_w_dir_perms;
# 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.
define(`dac_override_allowed', `{
dnsmasq
dumpstate
init
installd
install_recovery
userdebug_or_eng(`llkd')
lmkd
migrate_legacy_obb_data
netd
perfprofd
postinstall_dexopt
recovery
rss_hwm_reset
sdcardd
tee
ueventd
uncrypt
vendor_init
vold
vold_prepare_subdirs
zygote
}')
neverallow ~dac_override_allowed self:global_capability_class_set dac_override;
# Since the kernel checks dac_read_search before dac_override, domains that
# have dac_override should also have dac_read_search to eliminate spurious
# denials. Some domains have dac_read_search without having dac_override, so
# this list should be a superset of the one above.
neverallow ~{
dac_override_allowed
traced_probes
userdebug_or_eng(`heapprofd')
} self:global_capability_class_set dac_read_search;
# 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
-apexd
recovery_only(`userdebug_or_eng(`-fastbootd')')
-init
-kernel
-otapreopt_chroot
-recovery
-update_engine
-vold
-zygote
} { fs_type -sdcard_type }:filesystem { mount remount relabelfrom relabelto };
# Limit raw I/O to these allowlisted domains. Do not apply to debug builds.
neverallow {
domain
userdebug_or_eng(`-domain')
-kernel
-gsid
-init
-recovery
-ueventd
-healthd
-uncrypt
-tee
-hal_bootctl_server
} self:global_capability_class_set sys_rawio;