init: Weaken property override security for the init extension

Sometimes we need to override ro.* properties by using our vendor init
extension.

Previously there was a security check which was blocking that.
To resolve the issue, we need to weaken the security check during the
execution of our vendor init extension.

This is safe because the vendor init extension gets executed as part of init
construction and it is considered a trusted system component.

Change-Id: I6198b453745cb92c65d3e3d49e3262354cddd2a2
Signed-off-by: Alex Naidis <alex.naidis@linux.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>

init/property_service.cpp

@@ -132,6 +132,8 @@ struct PropertyAuditData {
     const char* name;
 };
 
+static bool weaken_prop_override_security = false;
+
 static int PropertyAuditCallback(void* data, security_class_t /*cls*/, char* buf, size_t len) {
     auto* d = reinterpret_cast<PropertyAuditData*>(data);
 
@@ -406,8 +408,8 @@ static std::optional<uint32_t> PropertySet(const std::string& name, const std::s
     } else {
         prop_info* pi = (prop_info*)__system_property_find(name.c_str());
         if (pi != nullptr) {
-            // ro.* properties are actually "write-once".
+            // ro.* properties are actually "write-once", unless the system decides to
-            if (StartsWith(name, "ro.")) {
+            if (StartsWith(name, "ro.") && !weaken_prop_override_security) {
                 *error = "Read-only property was already set";
                 return {PROP_ERROR_READ_ONLY_PROPERTY};
             }
@@ -1242,6 +1244,9 @@ void PropertyLoadBootDefaults() {
         }
     }
 
+    // Weaken property override security during execution of the vendor init extension
+    weaken_prop_override_security = true;
+
     // Update with vendor-specific property runtime overrides
     vendor_load_properties();
 
@@ -1252,6 +1257,9 @@ void PropertyLoadBootDefaults() {
     property_initialize_ro_cpu_abilist();
     property_initialize_ro_vendor_api_level();
 
+    // Restore the normal property override security after init extension is executed
+    weaken_prop_override_security = false;
+
     update_sys_usb_config();
 }