Re: [Qemu-devel] [PATCH] include/hw: field 'offset' in struct Property should be ptrdiff_t as int causes overflow

[Markus Armbruster <armbru@redhat.com>]

Stumbled over this while throwing away old mail.  Andreas, what do you
think?

Ildar Isaev <ild@inbox.ru> writes:

> 'offset' field in struct Property is calculated as a diff between two pointers (hw/core/qdev-properties.c:802)
>
> arrayprop->prop.offset = eltptr - (void *)dev;
>
> If offset is declared as int, this subtraction can cause type overflow
> thus leading to the fall of the subsequent assert (hw/core/qdev-properties.c:803)
>
> assert(qdev_get_prop_ptr(dev, &arrayprop->prop) == eltptr);
>
> So ptrdiff_t should be used instead
>
> Signed-off-by: Ildar Isaev <ild@inbox.ru>
> ---
>  include/hw/qdev-core.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index 4e673f9..f0e2a73 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -224,7 +224,7 @@ struct BusState {
>  struct Property {
>      const char   *name;
>      PropertyInfo *info;
> -    int          offset;
> +    ptrdiff_t    offset;
>      uint8_t      bitnr;
>      uint8_t      qtype;
>      int64_t      defval;