microdroid/sepolicy/system/private/zygote.te

# zygote
typeattribute zygote coredomain;
typeattribute zygote mlstrustedsubject;

init_daemon_domain(zygote)
tmpfs_domain(zygote)

read_runtime_log_tags(zygote)

# Override DAC on files and switch uid/gid.
allow zygote self:global_capability_class_set { dac_override dac_read_search setgid setuid fowner chown };

# Drop capabilities from bounding set.
allow zygote self:global_capability_class_set setpcap;

# Switch SELinux context to app domains.
allow zygote self:process setcurrent;
allow zygote system_server_startup:process dyntransition;
allow zygote appdomain:process dyntransition;
allow zygote webview_zygote:process dyntransition;
allow zygote app_zygote:process dyntransition;

# Allow zygote to read app /proc/pid dirs (b/10455872).
allow zygote appdomain:dir { getattr search };
allow zygote appdomain:file { r_file_perms };

userfaultfd_use(zygote)

# Move children into the peer process group.
allow zygote system_server:process { getpgid setpgid };
allow zygote appdomain:process { getpgid setpgid };
allow zygote webview_zygote:process { getpgid setpgid };
allow zygote app_zygote:process { getpgid setpgid };

# Read system data.
allow zygote system_data_file:dir r_dir_perms;
allow zygote system_data_file:file r_file_perms;

# Write to /data/dalvik-cache.
allow zygote dalvikcache_data_file:dir create_dir_perms;
allow zygote dalvikcache_data_file:file create_file_perms;

# Create symlinks in /data/dalvik-cache.
allow zygote dalvikcache_data_file:lnk_file create_file_perms;

# Write to /data/resource-cache.
allow zygote resourcecache_data_file:dir rw_dir_perms;
allow zygote resourcecache_data_file:file create_file_perms;

# For updateability, the zygote may fetch the current boot
# classpath from the dalvik cache. Integrity of the files
# is ensured by fsverity protection (checked in art_apex_boot_integrity).
allow zygote dalvikcache_data_file:file execute;

# Allow zygote to find files in APEX data directories.
allow zygote apex_module_data_file:dir search;

# Allow zygote to find and map files created by on device signing.
allow zygote apex_art_data_file:dir { getattr search };
allow zygote apex_art_data_file:file { r_file_perms execute };

# Bind mount on /data/data and mounted volumes
allow zygote { system_data_file mnt_expand_file }:dir mounton;

# Relabel /data/user /data/user_de and /data/data
allow zygote tmpfs:{ dir lnk_file } relabelfrom;
allow zygote system_data_file:{ dir lnk_file } relabelto;

# Zygote opens /mnt/expand to mount CE DE storage on each vol
allow zygote mnt_expand_file:dir { open read search relabelto };

# Bind mount subdirectories on /data/misc/profiles/cur
allow zygote user_profile_root_file:dir { mounton search };

# Create and bind dirs on /data/data
allow zygote tmpfs:dir { create_dir_perms mounton };

# Goes into media directory and bind mount obb directory
allow zygote media_rw_data_file:dir { getattr search };

# Bind mount on top of existing mounted obb and data directory
allow zygote media_rw_data_file:dir { mounton };

# Read if sdcardfs is supported
allow zygote proc_filesystems:file r_file_perms;

# Create symlink for /data/user/0
allow zygote tmpfs:lnk_file create;

allow zygote mirror_data_file:dir r_dir_perms;

# Get inode of directories for app data isolation
allow zygote {
  app_data_file_type
  system_data_file
  mnt_expand_file
}:dir getattr;

# Allow zygote to create JIT memory.
allow zygote self:process execmem;
allow zygote zygote_tmpfs:file execute;
allow zygote ashmem_libcutils_device:chr_file execute;

# Execute idmap and dex2oat within zygote's own domain.
# TODO:  Should either of these be transitioned to the same domain
# used by installd or stay in-domain for zygote?
allow zygote idmap_exec:file rx_file_perms;
allow zygote dex2oat_exec:file rx_file_perms;

# Allow apps access to /vendor/overlay
r_dir_file(zygote, vendor_overlay_file)

# Control cgroups.
allow zygote cgroup:dir create_dir_perms;
allow zygote cgroup:{ file lnk_file } r_file_perms;
allow zygote cgroup_v2:dir create_dir_perms;
allow zygote cgroup_v2:{ file lnk_file } { r_file_perms setattr };
allow zygote self:global_capability_class_set sys_admin;

# Allow zygote to stat the files that it opens. The zygote must
# be able to inspect them so that it can reopen them on fork
# if necessary: b/30963384.
allow zygote pmsg_device:chr_file getattr;
allow zygote debugfs_trace_marker:file getattr;

# Get seapp_contexts
allow zygote seapp_contexts_file:file r_file_perms;
# Check validity of SELinux context before use.
selinux_check_context(zygote)
# Check SELinux permissions.
selinux_check_access(zygote)

# Native bridge functionality requires that zygote replaces
# /proc/cpuinfo with /system/lib/<ISA>/cpuinfo using a bind mount
allow zygote proc_cpuinfo:file mounton;

# Allow remounting rootfs as MS_SLAVE.
allow zygote rootfs:dir mounton;
allow zygote tmpfs:filesystem { mount unmount };
allow zygote fuse:filesystem { unmount };
allow zygote sdcardfs:filesystem { unmount };

# Allow creating user-specific storage source if started before vold.
allow zygote mnt_user_file:dir { create_dir_perms mounton };
allow zygote mnt_user_file:lnk_file create_file_perms;
allow zygote mnt_user_file:file create_file_perms;

# Allow mounting user-specific storage source if started before vold.
allow zygote mnt_pass_through_file:dir { create_dir_perms mounton };

# Allowed to mount user-specific storage into place
allow zygote storage_file:dir { search mounton };

# Allow mounting and creating files, dirs on sdcardfs.
allow zygote { sdcard_type }:dir { create_dir_perms mounton };
allow zygote { sdcard_type }:file { create_file_perms };

# Handle --invoke-with command when launching Zygote with a wrapper command.
allow zygote zygote_exec:file rx_file_perms;

# Allow zygote to write to statsd.
unix_socket_send(zygote, statsdw, statsd)

# Root fs.
r_dir_file(zygote, rootfs)

# System file accesses.
r_dir_file(zygote, system_file)

# /oem accesses.
allow zygote oemfs:dir search;

userdebug_or_eng(`
  # Allow zygote to create and write method traces in /data/misc/trace.
  allow zygote method_trace_data_file:dir w_dir_perms;
  allow zygote method_trace_data_file:file { create w_file_perms };
')

allow zygote ion_device:chr_file r_file_perms;
allow zygote tmpfs:dir r_dir_perms;

allow zygote same_process_hal_file:file { execute read open getattr map };

# Allow the zygote to access storage properties to check if sdcardfs is enabled.
get_prop(zygote, storage_config_prop);

# Let the zygote access overlays so it can initialize the AssetManager.
get_prop(zygote, overlay_prop)
get_prop(zygote, exported_overlay_prop)

# Allow the zygote to access the runtime feature flag properties.
get_prop(zygote, device_config_runtime_native_prop)
get_prop(zygote, device_config_runtime_native_boot_prop)

# Allow the zygote to access window manager native boot feature flags
# to initialize WindowManager static properties.
get_prop(zygote, device_config_window_manager_native_boot_prop)

# ingore spurious denials
# fsetid can be checked as a consequence of chmod when using cgroup v2 uid/pid hierarchy. This is
# done to determine if the file should inherit setgid. In this case, setgid on the file is
# undesirable, so suppress the denial.
dontaudit zygote self:global_capability_class_set { sys_resource fsetid };

# Ignore spurious denials calling access() on fuse.
# Also ignore read and open as sdcardfs may read and open dir when app tries to access a dir that
# doesn't exist.
# TODO(b/151316657): avoid the denials
dontaudit zygote media_rw_data_file:dir  { read open setattr };

# Allow zygote to use ashmem fds from system_server.
allow zygote system_server:fd use;

# Send unsolicited message to system_server
unix_socket_send(zygote, system_unsolzygote, system_server)

# Allow zygote to access media_variant_prop for static initialization
get_prop(zygote, media_variant_prop)

# Allow zygote to read ro.control_privapp_permissions and ro.cp_system_other_odex
get_prop(zygote, packagemanager_config_prop)

# Allow zygote to read qemu.sf.lcd_density
get_prop(zygote, qemu_sf_lcd_density_prop)

# Allow zygote to read /apex/apex-info-list.xml
allow zygote apex_info_file:file r_file_perms;

###
### neverallow rules
###

# Ensure that all types assigned to app processes are included
# in the appdomain attribute, so that all allow and neverallow rules
# written on appdomain are applied to all app processes.
# This is achieved by ensuring that it is impossible for zygote to
# setcon (dyntransition) to any types other than those associated
# with appdomain plus system_server_startup, webview_zygote and
# app_zygote.
neverallow zygote ~{
  appdomain
  system_server_startup
  webview_zygote
  app_zygote
}:process dyntransition;

# Zygote should never execute anything from /data except for
# /data/dalvik-cache files or files generated during on-device
# signing under /data/misc/apexdata/com.android.art/.
neverallow zygote {
  data_file_type
  -apex_art_data_file # map PROT_EXEC
  -dalvikcache_data_file # map PROT_EXEC
}:file no_x_file_perms;

# Do not allow access to Bluetooth-related system properties and files
neverallow zygote {
  bluetooth_a2dp_offload_prop
  bluetooth_audio_hal_prop
  bluetooth_prop
  exported_bluetooth_prop
}:file create_file_perms;

# Zygote should not be able to access app private data.
neverallow zygote app_data_file_type:dir ~getattr;