diff --git a/media/libmediaplayerservice/Drm.cpp b/media/libmediaplayerservice/Drm.cpp
index e68d4cd..d50037f 100644
--- a/media/libmediaplayerservice/Drm.cpp
+++ b/media/libmediaplayerservice/Drm.cpp
@@ -28,9 +28,21 @@
 #include <media/stagefright/foundation/AString.h>
 #include <media/stagefright/foundation/hexdump.h>
 #include <media/stagefright/MediaErrors.h>
+#include <binder/IServiceManager.h>
+#include <binder/IPCThreadState.h>
 
 namespace android {
 
+static bool checkPermission(const char* permissionString) {
+#ifndef HAVE_ANDROID_OS
+    return true;
+#endif
+    if (getpid() == IPCThreadState::self()->getCallingPid()) return true;
+    bool ok = checkCallingPermission(String16(permissionString));
+    if (!ok) ALOGE("Request requires %s", permissionString);
+    return ok;
+}
+
 KeyedVector<Vector<uint8_t>, String8> Drm::mUUIDToLibraryPathMap;
 KeyedVector<String8, wp<SharedLibrary> > Drm::mLibraryPathToOpenLibraryMap;
 Mutex Drm::mMapLock;
@@ -608,6 +620,10 @@
         return -EINVAL;
     }
 
+    if (!checkPermission("android.permission.ACCESS_DRM_CERTIFICATES")) {
+        return -EPERM;
+    }
+
     return mPlugin->signRSA(sessionId, algorithm, message, wrappedKey, signature);
 }