Add a sysprop-as-API for Trusty Android properties
This provides access to the Android system properties that Trusty
defines. It does not grant any access to these properties from within
Trusty itself.
Bug: 382335252
Test: Use libtrustyproperties_rust in a rust_binary, call
Test: `trustyproperties::trustproperties::vm_cid()`
Change-Id: I7426eeaf6bee5cdb1eb644044a50953063440906
diff --git a/trusty/sysprops/Android.bp b/trusty/sysprops/Android.bp
new file mode 100644
index 0000000..ec27f51
--- /dev/null
+++ b/trusty/sysprops/Android.bp
@@ -0,0 +1,15 @@
+sysprop_library {
+ name: "trusty-properties",
+ srcs: ["android/sysprop/trusty/security_vm.sysprop"],
+ property_owner: "Platform",
+ api_packages: ["android.sysprop.trusty"],
+ apex_available: [
+ "//apex_available:platform",
+ ],
+}
+
+rust_binary {
+ name: "trusty-properties-example",
+ srcs: ["example.rs"],
+ rustlibs: ["libtrusty_properties_rust"],
+}
diff --git a/trusty/sysprops/android/sysprop/trusty/security_vm.sysprop b/trusty/sysprops/android/sysprop/trusty/security_vm.sysprop
new file mode 100644
index 0000000..a079ecf
--- /dev/null
+++ b/trusty/sysprops/android/sysprop/trusty/security_vm.sysprop
@@ -0,0 +1,67 @@
+# Copyright (C) 2025 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This module accesses properties regarding the Trusty VM that runs apps
+# used to provide security for the system, such as Keymint or Gatekeeper.
+
+module: "android.sysprop.trusty.security_vm"
+owner: Platform
+
+# The default Context Identifier to connect to Trusty over vsock.
+prop {
+ api_name: "vm_cid"
+ prop_name: "trusty.security_vm.vm_cid"
+ type: Integer
+ scope: Internal
+ access: Readonly
+}
+
+# Signals when a nonsecure VM is ready.
+#
+# This is used to launch dependent HALs.
+#
+# Trusty security VMs come in two flavors: non-secure and secure.
+#
+# 1. Non-secure VMs run on emulated environments like Cuttlefish, which lack
+# pVM firmware and TEE support. Consequently, KeyMint's root-of-trust data
+# is passed into the VM from the host's HAL, and an RPMB proxy provides
+# secure storage.
+# 2. Secure VMs run on physical devices. Here, pVM firmware handles the
+# transfer of root-of-trust data via DeviceTree, and a TEE provides secure
+# storage.
+prop {
+ api_name: "nonsecure_vm_ready"
+ prop_name: "trusty.security_vm.nonsecure_vm_ready"
+ type: Boolean
+ scope: Internal
+ access: Readonly
+}
+
+# The Trusty Security VM is enabled.
+prop {
+ api_name: "enabled"
+ prop_name: "trusty.security_vm.enabled"
+ type: Boolean
+ scope: Public
+ access: Readonly
+}
+
+# KeyMint is enabled in the Trusty Security VM.
+prop {
+ api_name: "keymint_enabled"
+ prop_name: "trusty.security_vm.keymint.enabled"
+ type: Boolean
+ scope: Public
+ access: Readonly
+}
diff --git a/trusty/sysprops/api/trusty-properties-current.txt b/trusty/sysprops/api/trusty-properties-current.txt
new file mode 100644
index 0000000..aa792fc
--- /dev/null
+++ b/trusty/sysprops/api/trusty-properties-current.txt
@@ -0,0 +1,11 @@
+props {
+ module: "android.sysprop.trusty.security_vm"
+ prop {
+ api_name: "enabled"
+ prop_name: "trusty.security_vm.enabled"
+ }
+ prop {
+ api_name: "keymint_enabled"
+ prop_name: "trusty.security_vm.keymint.enabled"
+ }
+}
diff --git a/trusty/sysprops/api/trusty-properties-latest.txt b/trusty/sysprops/api/trusty-properties-latest.txt
new file mode 100644
index 0000000..aa792fc
--- /dev/null
+++ b/trusty/sysprops/api/trusty-properties-latest.txt
@@ -0,0 +1,11 @@
+props {
+ module: "android.sysprop.trusty.security_vm"
+ prop {
+ api_name: "enabled"
+ prop_name: "trusty.security_vm.enabled"
+ }
+ prop {
+ api_name: "keymint_enabled"
+ prop_name: "trusty.security_vm.keymint.enabled"
+ }
+}
diff --git a/trusty/sysprops/example.rs b/trusty/sysprops/example.rs
new file mode 100644
index 0000000..f21e779
--- /dev/null
+++ b/trusty/sysprops/example.rs
@@ -0,0 +1,11 @@
+//! Example showing how to access the `trusty.security_vm.vm_cid` system property with Rust.
+
+use trusty_properties::security_vm;
+
+fn main() {
+ match security_vm::vm_cid() {
+ Ok(Some(cid)) => println!("CID: {cid}"),
+ Ok(None) => println!("CID property not set"),
+ Err(e) => println!("Error: {e:?}"),
+ }
+}