8214583: AccessController.getContext may return wrong value after JDK-8212605

Reviewed-by: mchung, redestad

src/hotspot/share/include/jvm.h

@@ -625,6 +625,15 @@ JVM_GetMethodParameters(JNIEnv *env, jobject method);
 JNIEXPORT jobject JNICALL
 JVM_GetInheritedAccessControlContext(JNIEnv *env, jclass cls);
 
+/*
+ * Ensure that code doing a stackwalk and using javaVFrame::locals() to
+ * get the value will see a materialized value and not a scalar-replaced
+ * null value.
+ */
+#define JVM_EnsureMaterializedForStackWalk(env, value) \
+    do {} while(0) // Nothing to do.  The fact that the value escaped
+                   // through a native method is enough.
+
 JNIEXPORT jobject JNICALL
 JVM_GetStackAccessControlContext(JNIEnv *env, jclass cls);
 

src/hotspot/share/prims/jvm.cpp

@@ -61,6 +61,7 @@
 #include "runtime/handles.inline.hpp"
 #include "runtime/init.hpp"
 #include "runtime/interfaceSupport.inline.hpp"
+#include "runtime/deoptimization.hpp"
 #include "runtime/java.hpp"
 #include "runtime/javaCalls.hpp"
 #include "runtime/jfieldIDWorkaround.hpp"
@@ -1245,8 +1246,12 @@ JVM_ENTRY(jobject, JVM_GetStackAccessControlContext(JNIEnv *env, jclass cls))
       javaVFrame *priv = vfst.asJavaVFrame();       // executePrivileged
 
       StackValueCollection* locals = priv->locals();
-      privileged_context = locals->obj_at(1);
-      Handle caller      = locals->obj_at(2);
+      StackValue* ctx_sv = locals->at(1); // AccessControlContext context
+      StackValue* clr_sv = locals->at(2); // Class<?> caller
+      assert(!ctx_sv->obj_is_scalar_replaced(), "found scalar-replaced object");
+      assert(!clr_sv->obj_is_scalar_replaced(), "found scalar-replaced object");
+      privileged_context    = ctx_sv->get_obj();
+      Handle caller         = clr_sv->get_obj();
 
       Klass *caller_klass = java_lang_Class::as_Klass(caller());
       protection_domain  = caller_klass->protection_domain();

src/java.base/share/classes/java/security/AccessController.java

@@ -709,6 +709,13 @@ public final class AccessController {
         return context;
     }
 
+    /**
+     * The value needs to be physically located in the frame, so that it
+     * can be found by a stack walk.
+     */
+    @Hidden
+    private static native void ensureMaterializedForStackWalk(Object o);
+
     /**
      * Sanity check that the caller context is indeed privileged.
      *
@@ -734,6 +741,11 @@ public final class AccessController {
                           AccessControlContext context,
                           Class<?> caller)
     {
+        // Ensure context has a physical value in the frame
+        if (context != null) {
+            ensureMaterializedForStackWalk(context);
+        }
+
         assert isPrivileged(); // sanity check invariant
         T result = action.run();
         assert isPrivileged(); // sanity check invariant
@@ -742,7 +754,6 @@ public final class AccessController {
         // retrieved by getStackAccessControlContext().
         Reference.reachabilityFence(context);
         Reference.reachabilityFence(caller);
-        Reference.reachabilityFence(action);
         return result;
     }
 
@@ -761,6 +772,11 @@ public final class AccessController {
                           Class<?> caller)
         throws Exception
     {
+        // Ensure context has a physical value in the frame
+        if (context != null) {
+            ensureMaterializedForStackWalk(context);
+        }
+
         assert isPrivileged(); // sanity check invariant
         T result = action.run();
         assert isPrivileged(); // sanity check invariant
@@ -769,7 +785,6 @@ public final class AccessController {
         // retrieved by getStackAccessControlContext().
         Reference.reachabilityFence(context);
         Reference.reachabilityFence(caller);
-        Reference.reachabilityFence(action);
         return result;
     }
 

src/java.base/share/native/libjava/AccessController.c

@@ -59,3 +59,12 @@ Java_java_security_AccessController_getInheritedAccessControlContext(
 {
     return JVM_GetInheritedAccessControlContext(env, this);
 }
+
+JNIEXPORT void JNICALL
+Java_java_security_AccessController_ensureMaterializedForStackWalk(
+                                                              JNIEnv *env,
+                                                              jclass cls,
+                                                              jobject value)
+{
+    JVM_EnsureMaterializedForStackWalk(env, value);
+}

test/jdk/java/security/AccessController/DoPriv.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8214583
+ * @summary Check that getContext works after JIT compiler escape analysis.
+ */
+import java.security.AccessControlContext;
+import java.security.AccessController;
+import java.security.DomainCombiner;
+import java.security.ProtectionDomain;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+import java.net.URL;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+public class DoPriv {
+
+    static void go(final DomainCombiner dc0, final AccessControlContext co, final int index) throws Exception {
+        final AccessControlContext ci = new AccessControlContext(co, dc0);
+        AccessController.doPrivileged((PrivilegedExceptionAction<Integer>)() -> {
+            AccessControlContext c1 = AccessController.getContext();
+            DomainCombiner dc = c1.getDomainCombiner();
+            if (dc != dc0 || dc == null) {
+                throw new AssertionError("iteration " + index + " " + dc + " != " + dc0);
+            }
+            return 0;
+        }, ci);
+    }
+
+    public static void main(String[] args) throws Exception {
+        final DomainCombiner dc0 = new DomainCombiner() {
+            public ProtectionDomain[] combine(ProtectionDomain[] currentDomains,
+                                            ProtectionDomain[] assignedDomains) {
+                return null;
+            }
+        };
+
+        final AccessControlContext co = AccessController.getContext();
+
+        for (int i = 0; i < 500_000; ++i) {
+            go(dc0, co, i);
+        }
+    }
+}

test/jdk/javax/security/auth/Subject/DoAs.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8214583
+ * @summary Check that getSubject works after JIT compiler escape analysis.
+ */
+import java.security.AccessControlContext;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.security.PrivilegedExceptionAction;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import javax.security.auth.Subject;
+
+public class DoAs {
+
+    public static void main(String[] args) throws Exception {
+        final Set<String> outer = new HashSet<>(Arrays.asList("Outer"));
+        final Subject subject = new Subject(true, Collections.EMPTY_SET, outer, Collections.EMPTY_SET);
+
+        for (int i = 0; i < 100_000; ++i) {
+            final int index = i;
+            Subject.doAs(subject, (PrivilegedExceptionAction<Integer>)() -> {
+                AccessControlContext c1 = AccessController.getContext();
+                Subject s = Subject.getSubject(c1);
+                if (s != subject) {
+                    throw new AssertionError("outer Oops! " + "iteration " + index + " " + s + " != " + subject);
+                }
+                return 0;
+            });
+        }
+    }
+}