platform_system_sepolicy/private/odsign.te

# odsign - on-device signing.
type odsign, domain;

# odsign - Binary for signing ART artifacts.
typeattribute odsign coredomain;

type odsign_exec, exec_type, file_type, system_file_type;

# Allow init to start odsign
init_daemon_domain(odsign)

# Allow using persistent storage in /data/odsign
allow odsign odsign_data_file:dir create_dir_perms;
allow odsign odsign_data_file:file create_file_perms;

# Allow using persistent storage in /data/odsign/metrics - to add metrics related files
allow odsign odsign_metrics_file:dir rw_dir_perms;
allow odsign odsign_metrics_file:file create_file_perms;

# Create and use pty created by android_fork_execvp().
create_pty(odsign)

# FS_IOC_ENABLE_VERITY and FS_IOC_MEASURE_VERITY on ART data files
allowxperm odsign apex_art_data_file:file ioctl {
  FS_IOC_ENABLE_VERITY FS_IOC_MEASURE_VERITY FS_IOC_GETFLAGS
};

# talk to binder services (for keystore)
binder_use(odsign);

# talk to keystore specifically
use_keystore(odsign);

# Use our dedicated keystore key
allow odsign odsign_key:keystore2_key {
    delete
    get_info
    rebind
    use
};

# talk to keymaster
hal_client_domain(odsign, hal_keymaster)

# For ART apex data dir access
allow odsign apex_module_data_file:dir { getattr search };

allow odsign apex_art_data_file:dir { rw_dir_perms rmdir rename };
allow odsign apex_art_data_file:file { rw_file_perms unlink };

# Run odrefresh to refresh ART artifacts
domain_auto_trans(odsign, odrefresh_exec, odrefresh)

# Run fsverity_init to add key to fsverity keyring
domain_auto_trans(odsign, fsverity_init_exec, fsverity_init)

# Run compos_verify to verify CompOs signatures
domain_auto_trans(odsign, compos_verify_exec, compos_verify)

# only odsign can set odsign sysprop
set_prop(odsign, odsign_prop)
neverallow { domain -odsign -init } odsign_prop:property_service set;

# Allow odsign to stop itself
set_prop(odsign, ctl_odsign_prop)

# Neverallows
neverallow { domain -odsign -init -fsverity_init} odsign_data_file:dir ~search;
neverallow { domain -odsign -init -fsverity_init} odsign_data_file:file *;