private/otapreopt_chroot.te

# otapreopt_chroot executable
typeattribute otapreopt_chroot coredomain;
type otapreopt_chroot_exec, exec_type, file_type, system_file_type;

# Chroot preparation and execution.
# We need to create an unshared mount namespace, and then mount /data.
allow otapreopt_chroot postinstall_file:dir { search mounton };
allow otapreopt_chroot apex_mnt_dir:dir mounton;
allow otapreopt_chroot device:dir mounton;
allow otapreopt_chroot linkerconfig_file:dir mounton;
allow otapreopt_chroot rootfs:dir mounton;
allow otapreopt_chroot sysfs:dir mounton;
allow otapreopt_chroot system_data_root_file:dir mounton;
allow otapreopt_chroot system_file:dir mounton;
allow otapreopt_chroot vendor_file:dir mounton;
allow otapreopt_chroot self:global_capability_class_set { sys_admin sys_chroot };

# This is required to mount /vendor and mount/unmount ext4 images from
# APEX packages in /postinstall/apex.
allow otapreopt_chroot block_device:dir search;
allow otapreopt_chroot labeledfs:filesystem { mount unmount };
# This is required for dynamic partitions.
allow otapreopt_chroot dm_device:chr_file rw_file_perms;

# This is required to unmount flattened APEX packages under
# /postinstall/system/apex (which are bind-mounted in /postinstall/apex).
allow otapreopt_chroot postinstall_file:filesystem unmount;
# Mounting /vendor can have this side-effect. Ignore denial.
dontaudit otapreopt_chroot kernel:process setsched;

# Allow otapreopt_chroot to read SELinux policy files.
allow otapreopt_chroot file_contexts_file:file r_file_perms;

# Allow otapreopt_chroot to open and read the contents of /postinstall/system/apex.
allow otapreopt_chroot postinstall_file:dir r_dir_perms;
# Allow otapreopt_chroot to read the persist.apexd.verity_on_system system property.
get_prop(otapreopt_chroot, apexd_prop)

# Allow otapreopt to use file descriptors from update-engine and the postinstall
# script. It will read dexopt commands from stdin and write progress to stdout.
allow otapreopt_chroot postinstall:fd use;
allow otapreopt_chroot postinstall:fifo_file { read write getattr };
allow otapreopt_chroot update_engine:fd use;
allow otapreopt_chroot update_engine:fifo_file write;

# Allow to transition to postinstall_dexopt, to run otapreopt in its own sandbox.
domain_auto_trans(otapreopt_chroot, postinstall_dexopt_exec, postinstall_dexopt)
domain_auto_trans(otapreopt_chroot, linkerconfig_exec, linkerconfig)
domain_auto_trans(otapreopt_chroot, apexd_exec, apexd)

# Allow otapreopt_chroot to control linkerconfig
allow otapreopt_chroot linkerconfig_file:dir { create_dir_perms relabelto };
allow otapreopt_chroot linkerconfig_file:file create_file_perms;

# Allow otapreopt_chroot to create loop devices with /dev/loop-control.
allow otapreopt_chroot loop_control_device:chr_file rw_file_perms;
# Allow otapreopt_chroot to access loop devices.
allow otapreopt_chroot loop_device:blk_file rw_file_perms;
allowxperm otapreopt_chroot loop_device:blk_file ioctl {
  LOOP_CONFIGURE
  LOOP_GET_STATUS64
  LOOP_SET_STATUS64
  LOOP_SET_FD
  LOOP_SET_BLOCK_SIZE
  LOOP_SET_DIRECT_IO
  LOOP_CLR_FD
  BLKFLSBUF
};

# Allow otapreopt_chroot to configure read-ahead of loop devices.
allow otapreopt_chroot sysfs_loop:dir r_dir_perms;
allow otapreopt_chroot sysfs_loop:file rw_file_perms;

# Allow otapreopt_chroot to mount a tmpfs filesystem in /postinstall/apex.
allow otapreopt_chroot tmpfs:filesystem mount;
# Allow otapreopt_chroot to restore the security context of /postinstall/apex.
allow otapreopt_chroot tmpfs:dir relabelfrom;
allow otapreopt_chroot postinstall_apex_mnt_dir:dir relabelto;

# Allow otapreopt_chroot to manipulate directory /postinstall/apex.
allow otapreopt_chroot postinstall_apex_mnt_dir:dir create_dir_perms;
allow otapreopt_chroot postinstall_apex_mnt_dir:file create_file_perms;
# Allow otapreopt_chroot to mount APEX packages in /postinstall/apex.
allow otapreopt_chroot postinstall_apex_mnt_dir:dir mounton;

# Allow otapreopt_chroot to access /dev/block (needed to detach loop
# devices used by ext4 images from APEX packages).
allow otapreopt_chroot block_device:dir r_dir_perms;

# Allow to access the linker through the symlink.
allow otapreopt_chroot postinstall_file:lnk_file r_file_perms;

# Allow otapreopt_chroot to read ro.cold_boot_done prop.
# This is a temporary solution to make sure that otapreopt_chroot doesn't block indefinetelly.
# TODO(b/165948777): remove this once otapreopt_chroot is migrated to libapexmount.
get_prop(otapreopt_chroot, cold_boot_done_prop)

# allow otapreopt_chroot to run the linkerconfig from the new image.
allow otapreopt_chroot linkerconfig_exec:file rx_file_perms;