Android: fix null array when requesting available providers

When requesting available positioning providers, the Java side can

  return new int[0];

in some cases. This is a perfectly valid way to return a zero-length
array in Java.
However, according to the linked bugreport, some JNI implementations
seem to convert it into nullptr, which later causes a crash when
passing a nullptr to GetIntArrayElements() JNI method.

Guard against it by explicitly checking that the array received from
the Java side is not nullptr.

Fixes: QTBUG-116645
Pick-to: 6.2
Change-Id: I657570ec5b0c62b994ed7d56c8142ab8992339b7
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 6148ae00cabca48def860970b48b2cb5dccdfff0)
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
(cherry picked from commit b6789681496d7716cc8cf1b2cca8d6a4dd410800)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/plugins/position/android/src/jnipositioning.cpp b/src/plugins/position/android/src/jnipositioning.cpp
index 9c2a7c7c..8025c2ff 100644
--- a/src/plugins/position/android/src/jnipositioning.cpp
+++ b/src/plugins/position/android/src/jnipositioning.cpp
@@ -191,6 +191,11 @@ namespace AndroidPositioning {
         QJniObject jniProvidersObj =
                 QJniObject::callStaticMethod<jobject>(positioningClass(), providerListMethodId);
         jintArray jProviders = jniProvidersObj.object<jintArray>();
+        if (!jProviders) {
+            // Work-around for QTBUG-116645
+            __android_log_print(ANDROID_LOG_INFO, logTag, "Got null providers array!");
+            return ret;
+        }
         jint *providers = env->GetIntArrayElements(jProviders, nullptr);
         const int size = env->GetArrayLength(jProviders);
         for (int i = 0; i < size; i++) {