android_system_sepolicy/private/apexd.te

typeattribute apexd coredomain;

init_daemon_domain(apexd)

# Read /system/etc/security/apex_debug_key
allow apexd apex_key_file:dir { search getattr };
allow apexd apex_key_file:file r_file_perms;

# Allow creating, reading and writing of APEX files/dirs in the APEX data dir
allow apexd apex_data_file:dir create_dir_perms;
allow apexd apex_data_file:file create_file_perms;

# allow apexd to create loop devices with /dev/loop-control
allow apexd loop_control_device:chr_file rw_file_perms;
# allow apexd to access loop devices
allow apexd loop_device:blk_file rw_file_perms;
allowxperm apexd loop_device:blk_file ioctl {
  LOOP_GET_STATUS64
  LOOP_SET_STATUS64
  LOOP_SET_FD
  LOOP_SET_BLOCK_SIZE
  LOOP_SET_DIRECT_IO
  LOOP_CLR_FD
  BLKFLSBUF
};
# allow apexd to access /dev/block
allow apexd block_device:dir r_dir_perms;

# allow apexd to access /dev/block/dm-* (device-mapper entries)
allow apexd dm_device:chr_file rw_file_perms;
allow apexd dm_device:blk_file rw_file_perms;

# sys_admin is required to access the device-mapper and mount
allow apexd self:global_capability_class_set sys_admin;

# allow apexd to create a mount point in /apex
allow apexd apex_mnt_dir:dir create_dir_perms;
# allow apexd to mount in /apex
allow apexd apex_mnt_dir:filesystem { mount unmount };
allow apexd apex_mnt_dir:dir mounton;
# allow apexd to create symlinks in /apex
allow apexd apex_mnt_dir:lnk_file create_file_perms;

# allow apexd to relabel apk_tmp_file to apex_data_file.
# TODO(b/112669193) remove this when APEXes are staged via file descriptor
allow apexd apk_tmp_file:file relabelfrom;
allow apexd apex_data_file:file relabelto;

# allow apexd to read files from /data/staging and hardlink them to /data/apex.
allow apexd staging_data_file:dir r_dir_perms;
allow apexd staging_data_file:file { r_file_perms link };

# Unmount and mount filesystems
allow apexd labeledfs:filesystem { mount unmount };

# Configure read-ahead of dm-verity and loop devices
# for dm-X
allow apexd sysfs_dm:dir r_dir_perms;
allow apexd sysfs_dm:file rw_file_perms;
# for loopX
allow apexd sysfs_loop:dir r_dir_perms;
allow apexd sysfs_loop:file rw_file_perms;

# Spawning a libbinder thread results in a dac_override deny,
# /dev/cpuset/tasks is owned by system.
#
# See b/35323867#comment3
dontaudit apexd self:global_capability_class_set { dac_override dac_read_search };

# Allow apexd to log to the kernel.
allow apexd kmsg_device:chr_file w_file_perms;

neverallow { domain -apexd -init } apex_data_file:dir no_w_dir_perms;
neverallow { domain -apexd -init -kernel } apex_data_file:file no_w_file_perms;
neverallow { domain -apexd } apex_mnt_dir:lnk_file no_w_file_perms;