[Entitlements] Add file read entitlement check to library load functions elastic#122494

Author: ldematte

libs/entitlement/qa/entitlement-test-plugin/src/main/java/org/elasticsearch/entitlement/qa/test/LoadNativeLibrariesCheckActions.java

@@ -12,15 +12,15 @@
 class LoadNativeLibrariesCheckActions {
     static void runtimeLoad() {
         try {
-            Runtime.getRuntime().load("libSomeLibFile.so");
+            Runtime.getRuntime().load(FileCheckActions.readDir().resolve("libSomeLibFile.so").toString());
         } catch (UnsatisfiedLinkError ignored) {
             // The library does not exist, so we expect to fail loading it
         }
     }
 
     static void systemLoad() {
         try {
-            System.load("libSomeLibFile.so");
+            System.load(FileCheckActions.readDir().resolve("libSomeLibFile.so").toString());
         } catch (UnsatisfiedLinkError ignored) {
             // The library does not exist, so we expect to fail loading it
         }

libs/entitlement/src/main/java/org/elasticsearch/entitlement/runtime/api/ElasticsearchEntitlementChecker.java

@@ -828,7 +828,7 @@ public void checkSelectorProviderInheritedChannel(Class<?> callerClass, Selector
 
     @Override
     public void check$java_lang_Runtime$load(Class<?> callerClass, Runtime that, String filename) {
-        // TODO: check filesystem entitlement READ
+        policyManager.checkFileRead(callerClass, Path.of(filename));
         policyManager.checkLoadingNativeLibraries(callerClass);
     }
 
@@ -839,7 +839,7 @@ public void checkSelectorProviderInheritedChannel(Class<?> callerClass, Selector
 
     @Override
     public void check$java_lang_System$$load(Class<?> callerClass, String filename) {
-        // TODO: check filesystem entitlement READ
+        policyManager.checkFileRead(callerClass, Path.of(filename));
         policyManager.checkLoadingNativeLibraries(callerClass);
     }