init: if vendor_init can read a property, let it be a trigger too
There is a list of 'stable_properties' that vendor_init can use as
property triggers for Treble property compliance. This list came about
since init parses init scripts before all partitions are mounted and
therefore before all property context files are available, such that
init cannot use the normal SELinux mechanisms for determining if a
given property is vendor_init readable.
Currently though, we require all partitions that would contain
property context files to be mounted during first stage mount, so we
can use the normal SELinux mechanisms here, so this change deprecates
the stable_properties list and moves init to use SELinux to determine
if a property can be a trigger.
Bug: 71814576
Test: vendor_init fails to use non-readable properties as a trigger
Test: vendor_init successfully uses readable properties as a trigger
Change-Id: I6a914e8c212a3418cbf4a8a07215056aad2e0162
diff --git a/init/property_service.cpp b/init/property_service.cpp
index 6aed0a3..5328869 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -111,6 +111,22 @@
LOG(FATAL) << "Failed to load serialized property info file";
}
}
+
+bool CanReadProperty(const std::string& source_context, const std::string& name) {
+ const char* target_context = nullptr;
+ property_info_area->GetPropertyInfo(name.c_str(), &target_context, nullptr);
+
+ PropertyAuditData audit_data;
+
+ audit_data.name = name.c_str();
+
+ ucred cr = {.pid = 0, .uid = 0, .gid = 0};
+ audit_data.cr = &cr;
+
+ return selinux_check_access(source_context.c_str(), target_context, "file", "read",
+ &audit_data) == 0;
+}
+
static bool CheckMacPerms(const std::string& name, const char* target_context,
const char* source_context, const ucred& cr) {
if (!target_context || !source_context) {