wininet: Handle NULL input for FindCloseUrlCache.

dlls/wininet/tests/urlcache.c

@@ -166,7 +166,18 @@ static void test_urlcacheA(void)
     ok(!ret && GetLastError() == ERROR_FILE_NOT_FOUND, "local file should no longer exist\n");
 }
 
+static void test_FindCloseUrlCache(void)
+{
+    BOOL r;
+    DWORD err;
+    r = FindCloseUrlCache(NULL);
+    err = GetLastError();
+    ok(0 == r, "expected 0, got %d\n", r);
+    ok(ERROR_INVALID_HANDLE == err, "expected %d, got %d\n", ERROR_INVALID_HANDLE, err);
+}
+
 START_TEST(urlcache)
 {
     test_urlcacheA();
+    test_FindCloseUrlCache();
 }

dlls/wininet/urlcache.c

@@ -3127,7 +3127,7 @@ BOOL WINAPI FindCloseUrlCache(HANDLE hEnumHandle)
 
     TRACE("(%p)\n", hEnumHandle);
 
-    if (pEntryHandle->dwMagic != URLCACHE_FIND_ENTRY_HANDLE_MAGIC)
+    if (!pEntryHandle || pEntryHandle->dwMagic != URLCACHE_FIND_ENTRY_HANDLE_MAGIC)
     {
         SetLastError(ERROR_INVALID_HANDLE);
         return FALSE;