platform_system_sepolicy/private/odsign.te
Alan Stokes 766caba5de Modify sepolicy for compos key changes
Add the compos_key_helper domain for the process which has access to
the signing key, make sure it can't be crashdumped. Also extend that
protection to diced & its HAL.

Rename compos_verify_key to compos_verify, because it doesn't verify
keys any more.

Move exec types used by Microdroid to file.te in the host rather than
their own dedicated files.

Bug: 218494522
Test: atest CompOsSigningHostTest CompOsDenialHostTest
Change-Id: I942667355d8ce29b3a9eb093e0b9c4f6ee0df6c1
2022-02-17 12:14:40 +00:00

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# 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;
# 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 };
# For CompOS instance & key files
allow odsign apex_compos_data_file:dir { getattr search };
allow odsign apex_compos_data_file:file r_file_perms;
# 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 *;
neverallow { domain -odsign -init -fsverity_init } odsign_data_file:file *;