RFR 8017271: Crash may occur in java.net.DualStackPlainSocketImpl::initIDs due to unchecked values returned from JNI functions

[Alan Bateman]

On 21/06/2013 14:50, Chris Hegarty wrote:
> There is a remote possibility that FindClass can return NULL, for a 
> class we expect to exist, OOM, etc. Best practice is to check the 
> return value before attempting to use it.
>
> CHECK_NULL [1] is a macro used in other places in the networking 
> native code for such checks. There will be a pending exception on the 
> stack if FindClass fails.
>
> diff -r 4503e04141f7 
> src/windows/native/java/net/DualStackPlainSocketImpl.c
> --- a/src/windows/native/java/net/DualStackPlainSocketImpl.c    Fri 
> Jun 21 18:26:13 2013 +0800
> +++ b/src/windows/native/java/net/DualStackPlainSocketImpl.c    Fri 
> Jun 21 14:39:52 2013 +0100
> @@ -43,6 +43,7 @@ JNIEXPORT void JNICALL Java_java_net_Dua
>    (JNIEnv *env, jclass clazz) {
>
>      jclass cls = (*env)->FindClass(env, "java/net/InetSocketAddress");
> +    CHECK_NULL(cls);
>      isa_class = (*env)->NewGlobalRef(env, cls);
>      isa_ctorID = (*env)->GetMethodID(env, cls, "<init>",
>                                       "(Ljava/net/InetAddress;I)V");
>
> -Chris.
>
> [1] #define CHECK_NULL(x) if ((x) == NULL) return;
>
I can only assume that memory is at exhaustion point for this to happen 
but what you have is fine (we should be checking it everywhere).

-Alan