sepolicy/private/artd.te

# ART service daemon.
typeattribute artd coredomain;
typeattribute artd mlstrustedsubject;
type artd_exec, system_file_type, exec_type, file_type;
type artd_tmpfs, file_type;

# All types of artd subprocesses, which artd can kill.
attribute artd_subprocess_type;

# Allow artd to publish a binder service and make binder calls.
binder_use(artd)
add_service(artd, artd_service)
add_service(artd, artd_pre_reboot_service)
allow artd dumpstate:fifo_file { getattr write };
allow artd dumpstate:fd use;

init_daemon_domain(artd)

# Allow query ART device config properties
get_prop(artd, device_config_runtime_native_prop)
get_prop(artd, device_config_runtime_native_boot_prop)

# Access to "odsign.verification.success" for deciding whether to deny files in
# the ART APEX data directory.
get_prop(artd, odsign_prop)

# Reading an APK opens a ZipArchive, which unpack to tmpfs.
# Use tmpfs_domain() which will give tmpfs files created by artd their
# own label, which differs from other labels created by other processes.
# This allows to distinguish in policy files created by artd vs other
# processes.
tmpfs_domain(artd)

# Allow testing userfaultfd support.
userfaultfd_use(artd)

# Read access to primary dex'es on writable partitions
# ({/data,/mnt/expand/<volume-uuid>}/app/...).
# Also allow creating the "oat" directory before restorecon.
allow artd mnt_expand_file:dir { getattr search };
allow artd apk_data_file:dir { rw_dir_perms create setattr relabelfrom };
allow artd apk_data_file:file r_file_perms;
allow artd apk_tmp_file:dir { rw_dir_perms create setattr relabelfrom };
allow artd apk_tmp_file:file r_file_perms;

# Read access to vendor APKs ({/vendor,/odm}/{app,priv-app}/...).
r_dir_file(artd, vendor_app_file)

# Read access to vendor overlay APKs ({/vendor,/odm,/oem,/apex/*}/overlay/...).
allow artd oemfs:dir { getattr search };
r_dir_file(artd, vendor_overlay_file)
# Vendor overlay can be found in vendor apex
allow artd vendor_apex_metadata_file:dir { getattr search };

# Read access to vendor shared libraries ({/vendor,/odm}/framework/...).
r_dir_file(artd, vendor_framework_file)

# Read/write access to all compilation artifacts generated on device for apps'
# primary dex'es. (/data/dalvik-cache/..., /data/app/.../oat/..., etc.)
allow artd dalvikcache_data_file:dir { create_dir_perms relabelto };
allow artd dalvikcache_data_file:file { create_file_perms relabelto };

# Read access to the ART APEX data directory.
# Needed for reading the boot image generated on device.
allow artd apex_module_data_file:dir { getattr search };
r_dir_file(artd, apex_art_data_file)

# Read access to /apex/apex-info-list.xml
# Needed for getting APEX versions.
allow artd apex_info_file:file r_file_perms;

# Allow getting root capabilities to bypass permission checks.
# - "dac_override" and "dac_read_search" are for
#   - reading secondary dex'es in app data directories (reading primary dex'es
#     doesn't need root capabilities)
#   - managing (CRUD) compilation artifacts in both APK directories for primary
#     dex'es and in app data directories for secondary dex'es
#   - managing (CRUD) profile files for both primary dex'es and secondary dex'es
# - "fowner" is for adjusting the file permissions of compilation artifacts and
#   profile files based on whether they include user data or not.
# - "chown" is for transferring the ownership of compilation artifacts and
#   profile files to the system or apps.
allow artd self:global_capability_class_set { dac_override dac_read_search fowner chown };

# Read/write access to profiles (/data/misc/profiles/{ref,cur}/...). Also allow
# scanning /data/misc/profiles/cur, for cleaning up obsolete managed files.
allow artd user_profile_root_file:dir r_dir_perms;
allow artd user_profile_data_file:dir rw_dir_perms;
allow artd user_profile_data_file:file create_file_perms;

# Read/write access to secondary dex files, their profiles, and their
# compilation artifacts
# ({/data,/mnt/expand/<volume-uuid>}/{user,user_de}/<user-id>/<package-name>/...).
allow artd app_data_file_type:dir { create_dir_perms relabelfrom relabelto };
allow artd app_data_file_type:file { create_file_perms relabelfrom relabelto };

# Allow symlinks for secondary dex files. This has be to restricted because
# symlinks can cause various security issues. We allow "privapp_data_file" just
# for GMS because so far we only see GMS using symlinks.
allow artd privapp_data_file:lnk_file { getattr read };

# Read access to SELinux context files, for restorecon.
allow artd file_contexts_file:file r_file_perms;
allow artd seapp_contexts_file:file r_file_perms;

# Check validity of SELinux context, for restorecon.
selinux_check_context(artd)

# Allow scanning /, for cleaning up obsolete managed files.
allow artd rootfs:dir r_dir_perms;

# Allow scanning /data, for cleaning up obsolete managed files.
allow artd system_data_root_file:dir r_dir_perms;

# Allow scanning /mnt, for cleaning up obsolete managed files.
allow artd tmpfs:dir r_dir_perms;

# Allow scanning /mnt/expand, for cleaning up obsolete managed files.
allow artd mnt_expand_file:dir r_dir_perms;

# Allow scanning {/data,/mnt/expand/<volume-uuid>}/{user,user_de}, for cleaning
# up obsolete managed files.
allow artd system_userdir_file:dir r_dir_perms;

# Allow scanning {/data,/mnt/expand/<volume-uuid>}/{user,user_de}/<user-id> and
# /mnt/expand/<volume-uuid>, for cleaning up obsolete managed files.
allow artd system_data_file:dir r_dir_perms;

# Allow art_exec_exec to use the artd domain because it is a thin wrapper that
# executes other binaries on behalf of artd. Domain transition will take place
# as soon as art_exec_exec executes other binaries.
allow artd art_exec_exec:file rx_file_perms;

# Allow running other binaries in their own domains.
domain_auto_trans(artd, profman_exec, profman)
domain_auto_trans(artd, dex2oat_exec, dex2oat)

# Allow sending sigkill to subprocesses.
allow artd artd_subprocess_type:process sigkill;

# Allow reading process info (/proc/<pid>/...).
# This is needed for getting CPU time and wall time spent on subprocesses.
r_dir_file(artd, profman);
r_dir_file(artd, dex2oat);

# Allow artd to reopen its own memfd.
# artd needs to reopen a memfd with readonly in order to pass it to subprocesses
# that don't have write permissions on memfds.
allow artd artd_tmpfs:file open;

# For Pre-reboot Dexopt.

# Allow init to execute artd through art_exec.
allow artd art_exec:fd use;

# During Pre-reboot Dexopt, artd needs one more capability:
# - "sys_admin" is for bind-mounting temp dirs at
#   /data/misc/apexdata/com.android.art and /data/misc/odrefresh, to run
#   odrefresh innocuously (in a way that doesn't affect the real boot images,
#   metrics, etc.).
allow artd self:global_capability_class_set sys_admin;

# Allow running other binaries in their own domains.
domain_auto_trans(artd, derive_classpath_exec, derive_classpath)
domain_auto_trans(artd, odrefresh_exec, odrefresh)

# Allow accessing Pre-reboot Dexopt files.
allow artd pre_reboot_dexopt_file:dir { getattr search };

# Allow reading /init.environ.rc in chroot, to extract env vars from it.
allow artd rootfs:file { read open getattr };

# Allow managing Pre-reboot Dexopt temp files.
# The root of the temp dir that artd uses during Pre-reboot Dexopt is labeled
# pre_reboot_dexopt_artd_file. Inside the temp dir, we create files and dirs and
# relabel them after creation, so we need relabelfrom.
allow artd pre_reboot_dexopt_artd_file:dir { create_dir_perms relabelfrom };
allow artd pre_reboot_dexopt_artd_file:file { create_file_perms relabelfrom };

# Allow bind-mounting at /data/misc/apexdata/com.android.art and
# /data/misc/odrefresh and restorecon, to run odrefresh innocuously.
allow artd { apex_art_data_file odrefresh_data_file }:dir relabelto;
allow artd { apex_art_data_file odrefresh_data_file pre_reboot_dexopt_artd_file }:dir mounton;

# Neverallow rules.

# Never allow running other binaries without a domain transition.
# The exception for art_exec_exec is explained above.
neverallow artd ~{art_exec_exec}:file execute_no_trans;

# Make sure artd_subprocess_type is complete, in a sense that it includes all
# types of artd subprocesses.
neverallow artd ~{artd_subprocess_type crash_dump}:process transition;

# artd uses process groups to manage subprocesses and kill them. To ensure
# successful kill, we need to prevent subprocesses from changing their
# process groups or transitioning to other domains.
# Transitioning crash_dump is allowed because it is transient and is only used
# upon crashes.
neverallow artd_subprocess_type self:process setpgid;
neverallow artd_subprocess_type ~{artd_subprocess_type crash_dump}:process transition;