platform_system_sepolicy/private/apexd.te

typeattribute apexd coredomain;

init_daemon_domain(apexd)

binder_use(apexd)
add_service(apexd, apex_service)

# 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 relabeling file created in /data/apex/decompressed
allow apexd apex_data_file:file relabelfrom;

# 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 reserving space on /data/apex/ota_reserved for apex decompression
allow apexd apex_ota_reserved_file:dir create_dir_perms;
allow apexd apex_ota_reserved_file:file create_file_perms;

# Allow apexd to create files and directories for snapshots of apex data
allow apexd apex_data_file_type:dir { create_dir_perms relabelto };
allow apexd apex_data_file_type:file { create_file_perms relabelto };
allow apexd apex_module_data_file:dir { create_dir_perms relabelfrom };
allow apexd apex_module_data_file:file { create_file_perms relabelfrom };
allow apexd apex_rollback_data_file:dir create_dir_perms;
allow apexd apex_rollback_data_file:file create_file_perms;

# Allow apexd to read /data/misc_de and the directories under it, in order to
# snapshot and restore apex data for all users.
allow apexd {
    system_userdir_file
    system_data_file
}:dir r_dir_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
  LOOP_CONFIGURE
};
# Allow apexd to access /dev/block
allow apexd dev_type:dir r_dir_perms;
allow apexd dev_type:blk_file getattr;

#allow apexd to access virtual disks
allow apexd vd_device:blk_file r_file_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
# dac_override, chown, and fowner are needed for snapshot and restore
allow apexd self:global_capability_class_set { sys_admin chown dac_override dac_read_search fowner };

# Note: fsetid is deliberately not included above. fsetid checks are
# triggered by chmod on a directory or file owned by a group other
# than one of the groups assigned to the current process to see if
# the setgid bit should be cleared, regardless of whether the setgid
# bit was even set.  We do not appear to truly need this capability
# for apexd to operate.
dontaudit apexd self:global_capability_class_set fsetid;

# 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 create /apex/apex-info-list.xml and relabel to apex_info_file
allow apexd apex_mnt_dir:file { create_file_perms relabelfrom mounton };
allow apexd apex_info_file:file relabelto;
# apexd needs to update /apex/apex-info-list.xml after non-staged APEX update.
allow apexd apex_info_file:file rw_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 };
# # Allow relabeling file created in /data/apex/decompressed
allow apexd staging_data_file:file relabelto;

# allow apexd to read files from /vendor/apex
r_dir_file(apexd, vendor_apex_file)
r_dir_file(apexd, vendor_apex_metadata_file)

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

# /sys directory tree traversal
allow apexd sysfs_type:dir search;
# Access to /sys/class/block
allow apexd sysfs_type:dir r_dir_perms;
allow apexd sysfs_type:file r_file_perms;
# 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;

# 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)

# Allow apexd to stop itself
set_prop(apexd, ctl_apexd_prop)

# Allow apexd to send control messages to load/unload apex from init
set_prop(apexd, ctl_apex_load_prop)

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

# apexd is using bootstrap bionic
use_bootstrap_libs(apexd)

# Allow apexd to be invoked with logwrapper from init during userspace reboot.
allow apexd devpts:chr_file { read write };

# Allow apexd to create pts files via logwrap_fork_exec for its own use, to pass to
# other processes
create_pty(apexd)

# Allow apexd to read file contexts when performing restorecon of snapshots.
allow apexd file_contexts_file:file r_file_perms;

# Allow apexd to execute toybox for snapshot & restore
allow apexd toolbox_exec:file rx_file_perms;

# Allow apexd to release compressed blocks in case /data is f2fs-compressed fs.
allowxperm apexd staging_data_file:file ioctl {
  FS_IOC_GETFLAGS
  F2FS_IOC_RELEASE_COMPRESS_BLOCKS
};

# Allow apexd to read ro.cold_boot_done prop.
# apexd uses it to decide whether it needs to keep retrying polling for loop device.
get_prop(apexd, cold_boot_done_prop)

# Allow apexd to read per-device configuration properties.
get_prop(apexd, apexd_config_prop)

# Allow apexd to read apex selection properties.
# These are used to choose between multi-installed APEXes at activation time.
get_prop(apexd, apexd_select_prop)
#
# Allow apexd to read apexd_payload_metadata_prop
get_prop(apexd, apexd_payload_metadata_prop)

set_prop(apexd, apexd_prop)

# Allow for use in postinstall
allow apexd otapreopt_chroot:fd use;
allow apexd postinstall_apex_mnt_dir:dir { create_dir_perms mounton };
allow apexd postinstall_apex_mnt_dir:file { create_file_perms relabelfrom };
allow apexd postinstall_apex_mnt_dir:lnk_file create;
allow apexd proc_filesystems:file r_file_perms;

# Allow for use in Pre-reboot Dexopt.
allow apexd dexopt_chroot_setup:fd use;

# Allow calling derive_classpath to gather BCP information for staged sessions
domain_auto_trans(apexd, derive_classpath_exec, apexd_derive_classpath);

# Allow set apex ready property
set_prop(apexd, apex_ready_prop)

# Allow apexd to write to statsd.
unix_socket_send(apexd, statsdw, statsd)

###
### Neverallow rules
###

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;

neverallow { domain -apexd -init -vold_prepare_subdirs } apex_module_data_file:dir no_w_dir_perms;
neverallow { domain -apexd -init -vold_prepare_subdirs } apex_module_data_file:file no_w_file_perms;

neverallow { domain -apexd -init -vold_prepare_subdirs } apex_rollback_data_file:dir no_w_dir_perms;
neverallow { domain -apexd -init -vold_prepare_subdirs } apex_rollback_data_file:file no_w_file_perms;

# only apexd can set apexd sysprop
neverallow { domain -apexd -init } apexd_prop:property_service set;

# only apexd can write apex-info-list.xml
neverallow { domain -apexd } apex_info_file:file no_w_file_perms;

# Only apexd and init should be allowed to manage /apex mounts
# A note on otapreopt_chroot. It used to mount APEXes during postainstall stage of A/B OTAs,
# but starting from S it just calls into apexd to prepare /apex for otapreoprt. Once the sepolicies
# around otapreopt_chroot are cleaned up we should be able to remove it from the lists below.
# dexopt_chroot_setup calls apexd to prepare /apex for Pre-reboot Dexopt, but it
# needs to mount a tmpfs on /apex for apexd to work on.
neverallow { domain -apexd -init -otapreopt_chroot } apex_mnt_dir:filesystem { mount unmount };
neverallow { domain -apexd -dexopt_chroot_setup -init -otapreopt_chroot } apex_mnt_dir:dir mounton;

neverallow { domain -init -apexd -system_server -update_engine } apex_service:service_manager find;
neverallow { domain -init -apexd -system_server -servicemanager -update_engine } apexd:binder call;

neverallow { domain userdebug_or_eng(`-crash_dump') } apexd:process ptrace;