platform_system_sepolicy/public/fastbootd.te

# fastbootd (used in recovery init.rc for /sbin/fastbootd)

# Declare the domain unconditionally so we can always reference it
# in neverallow rules.
type fastbootd, domain;

# But the allow rules are only included in the recovery policy.
# Otherwise fastbootd is only allowed the domain rules.
recovery_only(`
  # fastbootd can only use HALs in passthrough mode
  passthrough_hal_client_domain(fastbootd, hal_bootctl)

  # Access /dev/usb-ffs/fastbootd/ep0
  allow fastbootd functionfs:dir search;
  allow fastbootd functionfs:file rw_file_perms;

  allowxperm fastbootd functionfs:file ioctl { FUNCTIONFS_ENDPOINT_DESC };
  # Log to serial
  allow fastbootd kmsg_device:chr_file { open write };

  # battery info
  allow fastbootd sysfs_batteryinfo:file r_file_perms;

  allow fastbootd device:dir r_dir_perms;

  # Reboot the device
  set_prop(fastbootd, powerctl_prop)

  # Read serial number of the device from system properties
  get_prop(fastbootd, serialno_prop)

  # Set sys.usb.ffs.ready.
  set_prop(fastbootd, ffs_prop)
  set_prop(fastbootd, exported_ffs_prop)

  unix_socket_connect(fastbootd, recovery, recovery)

  # Required for flashing
  allow fastbootd dm_device:chr_file rw_file_perms;
  allow fastbootd dm_device:blk_file rw_file_perms;

  allow fastbootd super_block_device:blk_file rw_file_perms;
  allow fastbootd {
    boot_block_device
    metadata_block_device
    system_block_device
    userdata_block_device
  }:blk_file { w_file_perms getattr ioctl };

  allowxperm fastbootd {
    system_block_device
    super_block_device
  }:blk_file ioctl { BLKIOMIN BLKALIGNOFF };

  allowxperm fastbootd {
    metadata_block_device
    userdata_block_device
  }:blk_file ioctl { BLKSECDISCARD BLKDISCARD };

  allow fastbootd misc_block_device:blk_file rw_file_perms;

  allow fastbootd proc_cmdline:file r_file_perms;
  allow fastbootd rootfs:dir r_dir_perms;

  # Needed to read fstab node from device tree.
  allow fastbootd sysfs_dt_firmware_android:file r_file_perms;
  allow fastbootd sysfs_dt_firmware_android:dir r_dir_perms;

  # Needed for realpath() call to resolve symlinks.
  allow fastbootd block_device:dir getattr;
  userdebug_or_eng(`
    # Refined manipulation of /mnt/scratch, without these perms resorts
    # to deleting scratch partition when partition(s) are flashed.
    allow fastbootd self:process setfscreate;
    allow fastbootd overlayfs_file:dir { create_dir_perms mounton };
    allow fastbootd {
      system_file_type
      unlabeled
      vendor_file_type
    }:dir { remove_name rmdir search write };
    allow fastbootd {
      overlayfs_file
      system_file_type
      unlabeled
      vendor_file_type
    }:{ file lnk_file } unlink;
    allow fastbootd tmpfs:dir rw_dir_perms;
    allow fastbootd labeledfs:filesystem { mount unmount };
    get_prop(fastbootd, persistent_properties_ready_prop)
  ')
')

###
### neverallow rules
###

# Write permission is required to wipe userdata
# until recovery supports vold.
neverallow fastbootd {
   data_file_type
}:file { no_x_file_perms };