[Libreoffice-commits] core.git: connectivity/source

[Stephan Bergmann (via logerrit)]

 connectivity/source/drivers/jdbc/Class.cxx |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

New commits:
commit 27c6d1dbdb3dcad02a244ab942adb9222a461e44
Author:     Stephan Bergmann <sbergman at redhat.com>
AuthorDate: Wed Apr 24 16:08:06 2019 +0200
Commit:     Stephan Bergmann <sbergman at redhat.com>
CommitDate: Wed Apr 24 17:47:24 2019 +0200

    Avoid calling java.lang.Class.newInstance()
    
    For one, it is deprecated since Java 9, and for another it causes a
    NullPointerException when called from the JNI Invocation API (i.e., without a
    Java caller frame) at least with some Java 12.
    
    (Found when doing a test build with Java 12 and JAVA_SOURCE/TARGET_VER
    explicitly configured as 7 with d365f36331874f94bbd9832fbd19ace90fafefec "Allow
    to pass JAVA_SOURCE/TARGET_VER into configure".)
    
    I have entered information about the NullPointerException at
    <https://bugreport.java.com/bugreport/start_form.do>, but haven't heard back
    yet, so duplicate that information here:
    
    Issue Type:
    > Bug
    
    Component:
    > Core Libraries
    
    Operating System:
    > Linux 64-bit
    
    Java Release:
    > 12
    
    Synopsis:
    > Calling java.lang.Class.newInstance from JNI Invocation API causes NullPointerEx
    
    Description:
    > I can reproduce this with the OpenJDK 12 RPMs on Fedora 30, but from looking at <https://hg.openjdk.java.net/jdk/jdk12/file/06222165c35f/src/java.base/share/classes/java/lang/Class.java> it looks plausible that it is a common issue that Reflection.getCallerClass() returns null when java.lang.Class.newInstance is called from the JNI Invocation API, and that null is propagated to jdk.internal.reflect.Reflection.verifyMemberAccess as parameter currentClass, which dereferences it at <https://hg.openjdk.java.net/jdk/jdk12/file/06222165c35f/src/java.base/share/classes/jdk/internal/reflect/Reflection.java#l130>.
    > This is known to have been working with older OpenJDK (at least 1.8).
    
    Steps to Reproduce:
    > Compile the provided test.cc with `g++ -I/usr/lib/jvm/java-12-openjdk-12.0.0.33-1.ea.1.rolling.fc30.x86_64/include -I/usr/lib/jvm/java-12-openjdk-12.0.0.33-1.ea.1.rolling.fc30.x86_64/include/linux /usr/lib/jvm/java-12-openjdk-12.0.0.33-1.ea.1.rolling.fc30.x86_64/lib/server/libjvm.so test.cc` and run it with `LD_LIBRARY_PATH=/usr/lib/jvm/java-12-openjdk-12.0.0.33-1.ea.1.rolling.fc30.x86_64/lib/server ./a.out`.
    
    Expected Result:
    > exit 0
    
    Actual Result:
    > Exception in thread "main" java.lang.NullPointerException
    >       at java.base/jdk.internal.reflect.Reflection.verifyMemberAccess(Reflection.java:130)
    >       at java.base/java.lang.reflect.AccessibleObject.slowVerifyAccess(AccessibleObject.java:673)
    >       at java.base/java.lang.reflect.AccessibleObject.verifyAccess(AccessibleObject.java:666)
    >       at java.base/java.lang.reflect.AccessibleObject.checkAccess(AccessibleObject.java:638)
    >       at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:490)
    >       at java.base/java.lang.reflect.ReflectAccess.newInstance(ReflectAccess.java:166)
    >       at java.base/jdk.internal.reflect.ReflectionFactory.newInstance(ReflectionFactory.java:404)
    >       at java.base/java.lang.Class.newInstance(Class.java:590)
    > Aborted
    
    Source code for an executable test case:
    > #include <cstdlib>
    >
    > #include "jni.h"
    >
    > void handleError(JNIEnv * env) {
    >     if (env->ExceptionCheck()) {
    >         env->ExceptionDescribe();
    >         std::abort();
    >     }
    > }
    >
    > int main() {
    >     JavaVM * vm;
    >     JNIEnv * env;
    >     JavaVMInitArgs args{JNI_VERSION_1_2, 0, nullptr, true};
    >     if (JNI_CreateJavaVM(&vm, reinterpret_cast<void **>(&env), &args) != JNI_OK) {
    >         std::abort();
    >     }
    >     auto const c1 = env->FindClass("java/lang/Class");
    >     handleError(env);
    >     auto const id = env->GetMethodID(c1, "newInstance", "()Ljava/lang/Object;");
    >     handleError(env);
    >     auto const c2 = env->FindClass("java/lang/Object");
    >     handleError(env);
    >     env->CallObjectMethod(c2, id);
    >     handleError(env);
    > }
    
    Workaround:
    > Call via JNI the suggested replacement of clazz.getDeclaredConstructor().newInstance() instead of the deprecated java.lang.Class.newInstance().
    
    Change-Id: I85ff7102a18b98561f188e609873753546bc050d
    Reviewed-on: https://gerrit.libreoffice.org/71240
    Tested-by: Jenkins
    Reviewed-by: Stephan Bergmann <sbergman at redhat.com>

diff --git a/connectivity/source/drivers/jdbc/Class.cxx b/connectivity/source/drivers/jdbc/Class.cxx
index b41d2f596933..c4dc3f4b5286 100644
--- a/connectivity/source/drivers/jdbc/Class.cxx
+++ b/connectivity/source/drivers/jdbc/Class.cxx
@@ -57,8 +57,15 @@ java_lang_Class * java_lang_Class::forName( const OUString& _par0 )
 jobject java_lang_Class::newInstanceObject()
 {
     SDBThreadAttach t;
-    static jmethodID mID(nullptr);
-    return callObjectMethod(t.pEnv,"newInstance","()Ljava/lang/Object;", mID);
+    auto const id = t.pEnv->GetMethodID(static_cast<jclass>(object), "<init>", "()V");
+    if (id == nullptr) {
+        ThrowSQLException(t.pEnv, nullptr);
+    }
+    auto const obj = t.pEnv->NewObject(static_cast<jclass>(object), id);
+    if (obj == nullptr) {
+        ThrowSQLException(t.pEnv, nullptr);
+    }
+    return obj;
 }
 
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