Allow CompOS to read VM config properties

We want to allow both the VM and ART to contribute to the VM config
(e.g. memory size), so define labels for 2 sets of properties and
grant the necessary access.

Bug: 274102209
Test: builds
Change-Id: Iaca1e0704301c9155f44e1859fc5a36198917568
diff --git a/private/composd.te b/private/composd.te
index 96991c6..68dd993 100644
--- a/private/composd.te
+++ b/private/composd.te
@@ -30,9 +30,16 @@
 domain_auto_trans(composd, fd_server_exec, compos_fd_server)
 allow composd compos_fd_server:process signal;
 
+# Read properties used to configure the CompOS VM
+get_prop(composd, composd_vm_art_prop)
+get_prop(composd, composd_vm_vendor_prop)
+
 # Read ART's properties
 get_prop(composd, dalvik_config_prop)
 get_prop(composd, device_config_runtime_native_boot_prop)
 
 # We never create any artifact files directly
 neverallow composd apex_art_data_file:file create;
+
+# ART sets these properties via init script, nothing else should
+neverallow { domain -init } composd_vm_art_prop:property_service set;