diff --git a/modules/libjar/nsZipArchive.cpp b/modules/libjar/nsZipArchive.cpp
index 684129a2895..57ffc85c8df 100644
--- a/modules/libjar/nsZipArchive.cpp
+++ b/modules/libjar/nsZipArchive.cpp
@@ -124,10 +124,10 @@ static void *
 zlibAlloc(void *opaque, uInt items, uInt size)
 {
   nsRecyclingAllocator *zallocator = (nsRecyclingAllocator *)opaque;
-  if (gZlibAllocator) {
-    return gZlibAllocator->Calloc(items, size);
+  if (zallocator) {
+    return gZlibAllocator->Malloc(items * size);
   }
-  return calloc(items, size);
+  return malloc(items * size);
 }
 
 static void