android10/system/sepolicy/private/apexd.te

typeattribute apexd coredomain;

init_daemon_domain(apexd)

# 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 creating, reading and writing of APEX files/dirs in the APEX metadata dir
allow apexd metadata_file:dir search;
allow apexd apex_metadata_file:dir create_dir_perms;
allow apexd apex_metadata_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 unlink apex files in /data/apex/active
# note that apexd won't be able to unlink files in /data/app-staging/session_XXXX,
# because it doesn't have write permission for staging_data_file object.
allow apexd staging_data_file:file unlink;

# allow apexd to read files from /data/app-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 };

# /sys directory tree traversal
allow apexd sysfs_type:dir search;
# 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;

# Allow apexd to reboot device. Required for rollbacks of apexes that are
# not covered by rollback manager.
set_prop(apexd, powerctl_prop)

# Find the vold service, and call into vold to manage FS checkpoints
allow apexd vold_service:service_manager find;
binder_call(apexd, vold)

# Apex pre- & post-install permission.

# Allow self-execute for the fork mount helper.
allow apexd apexd_exec:file execute_no_trans;

# Unshare and make / private so that hooks cannot influence the
# running system.
allow apexd rootfs:dir mounton;

# Allow to execute shell for pre- and postinstall scripts. A transition
# rule is required, thus restricted to execute and not execute_no_trans.
allow apexd shell_exec:file { r_file_perms execute };

# apexd is using bootstrap bionic
allow apexd system_bootstrap_lib_file:dir r_dir_perms;
allow apexd system_bootstrap_lib_file:file { execute read open getattr map };

# Allow transition to ART APEX preinstall domain.
domain_auto_trans(apexd, art_apex_preinstall_exec, art_apex_preinstall)
# Allow transition to ART APEX postinstall domain.
domain_auto_trans(apexd, art_apex_postinstall_exec, art_apex_postinstall)

# Allow transition to test APEX preinstall domain.
userdebug_or_eng(`
  domain_auto_trans(apexd, apex_test_prepostinstall_exec, apex_test_prepostinstall)
')

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