microdroid/system/private/microdroid_manager.te

# microdroid_manager is a daemon running in the microdroid.

type microdroid_manager, domain, coredomain;
type microdroid_manager_exec, exec_type, file_type, system_file_type;

# allow domain transition from init
init_daemon_domain(microdroid_manager)

# Allow microdroid_manager to set boot status
set_prop(microdroid_manager, boot_status_prop)

# microdroid_manager accesses a virtual disk block device to read VM payload
# It needs write access as it updates the instance image
allow microdroid_manager block_device:dir r_dir_perms;
allow microdroid_manager block_device:lnk_file r_file_perms;
allow microdroid_manager vd_device:blk_file rw_file_perms;
# microdroid_manager verifies DM-verity mounted APK payload
allow microdroid_manager dm_device:blk_file r_file_perms;

# microdroid_manager can query AVF flags in the device tree
r_dir_file(microdroid_manager, proc_dt_avf)
r_dir_file(microdroid_manager, sysfs_dt_avf)

# Read config from the open-dice driver.
allow microdroid_manager open_dice_device:chr_file rw_file_perms;

# Block crash dumps to ensure the DICE secrets are not leaked.
typeattribute microdroid_manager no_crash_dump_domain;

# Allow microdroid_manager to do blkflsbuf on instance disk image. The ioctl
# requires sys_admin cap as well.
allowxperm microdroid_manager vd_device:blk_file ioctl BLKFLSBUF;
allow microdroid_manager self:global_capability_class_set sys_admin;

# Allow microdroid_manager to remove capabilities from it's capability bounding set.
allow microdroid_manager self:global_capability_class_set setpcap;

# Allow microdroid_manager to start payload tasks in a different uid/gid.
domain_auto_trans(microdroid_manager, microdroid_app_exec, microdroid_app)
domain_auto_trans(microdroid_manager, compos_exec, compos)
allow microdroid_manager self:global_capability_class_set { setuid setgid };

# Allow microdroid_manager to start apk verity binaries
domain_auto_trans(microdroid_manager, apkdmverity_exec, apkdmverity)
domain_auto_trans(microdroid_manager, zipfuse_exec, zipfuse)

# Allow microdroid_manager to start encryptedstore binary
domain_auto_trans(microdroid_manager, encryptedstore_exec, encryptedstore)

# Microdroid Manager needs read related permission for syncing encrypted storage fs
allow microdroid_manager encryptedstore_file:dir r_dir_perms;

# Allow microdroid_manager to run kexec to load crashkernel
domain_auto_trans(microdroid_manager, kexec_exec, kexec)

# Let microdroid_manager kernel-log.
allow microdroid_manager kmsg_device:chr_file w_file_perms;

# Let microdroid_manager to create a vsock connection back to the host VM
allow microdroid_manager self:vsock_socket { create_socket_perms_no_ioctl };

# Allow microdroid_manager to read the CID of the VM.
allow microdroid_manager vsock_device:chr_file { ioctl open read };

# microdroid_manager is using bootstrap bionic
use_bootstrap_libs(microdroid_manager)

# microdroid_manager create /apex/vm-payload-metadata for apexd
# TODO(b/199371341) create a new label for the file so that only microdroid_manager can create it.
allow microdroid_manager apex_mnt_dir:dir w_dir_perms;
allow microdroid_manager apex_mnt_dir:file create_file_perms;

# Allow microdroid_manager to start various services
set_prop(microdroid_manager, ctl_apexd_vm_prop)
set_prop(microdroid_manager, ctl_apkdmverity_prop)
set_prop(microdroid_manager, ctl_authfs_prop)
set_prop(microdroid_manager, ctl_seriallogging_prop)
set_prop(microdroid_manager, ctl_zipfuse_prop)

# Allow microdroid_manager to wait for linkerconfig to be ready
get_prop(microdroid_manager, apex_config_prop)

# Allow microdroid_manager to wait for zipfuse to be ready
get_prop(microdroid_manager, microdroid_manager_zipfuse_prop)

# Allow microdroid_manager to pass the roothash to apkdmverity
set_prop(microdroid_manager, microdroid_manager_roothash_prop)

# Allow microdroid_manager to set sysprops calculated from the payload config
set_prop(microdroid_manager, microdroid_config_prop)

# Allow microdroid_manager to set sysprops related to microdroid_lifecycle (ex. init_done)
set_prop(microdroid_manager, microdroid_lifecycle_prop)

# Allow microdroid_manager to shutdown the device when verification fails
set_prop(microdroid_manager, powerctl_prop)

# Allow microdroid_manager to read bootconfig so that it can reject a bootconfig
# that is different from what is recorded in the instance.img file.
allow microdroid_manager proc_bootconfig:file r_file_perms;

# microdroid_manager needs to read /proc/cmdline to see if crashkernel= parameter is set
# or not; if set, it executes kexec to load the crashkernel into memory.
allow microdroid_manager proc_cmdline:file r_file_perms;

# microdroid_manager needs to read /proc/stat and /proc_meminfo to collect CPU & memory usage
# for creating atoms used in AVF telemetry metrics
allow microdroid_manager proc_meminfo:file r_file_perms;
allow microdroid_manager proc_stat:file r_file_perms;

# Allow microdroid_manager to set up zram-backed swap:
#  - Read & Write zram properties in sysfs to set/get zram disksize
#  - Read & Write to zram block device needed for mkswap and swapon
allow microdroid_manager sysfs_zram:dir { search };
allow microdroid_manager sysfs_zram:file rw_file_perms;
allow microdroid_manager ram_device:blk_file rw_file_perms;

# Allow microdroid_manager to read/write failure serial device
allow microdroid_manager serial_device:chr_file w_file_perms;

# Allow microdroid_manager to handle extra_apks
allow microdroid_manager extra_apk_file:dir create_dir_perms;

# Allow microdroid_manager to write kmsg_debug (stdio_to_kmsg).
allow microdroid_manager kmsg_debug_device:chr_file w_file_perms;

# Domains other than microdroid can't write extra_apks
neverallow { domain -microdroid_manager -init -vendor_init } extra_apk_file:file no_w_file_perms;
neverallow { domain -microdroid_manager -init -vendor_init } extra_apk_file:dir no_w_dir_perms;

# Only microdroid_payload and a few other critical binaries can be run by microdroid_manager,
# in their own domains.
neverallow microdroid_manager { file_type fs_type }:file execute_no_trans;
neverallow microdroid_manager {
  domain
  -crash_dump
  -microdroid_payload
  -apkdmverity
  -encryptedstore
  -zipfuse
  -kexec
}:process transition;