On Tue, 4 Dec 2023, Juergen Gross wrote:
> Update the Xen PV-device interface headers in order to avoid undefined
> behavior with flexible arrays being defined with one array element.
>
> Reported-by: Pry Mar <[email protected]>
> Signed-off-by: Juergen Gross <[email protected]>
Acked-by: Stefano Stabellini <[email protected]>
> ---
> include/xen/interface/io/displif.h | 2 +-
> include/xen/interface/io/ring.h | 2 +-
> include/xen/interface/io/sndif.h | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/xen/interface/io/displif.h b/include/xen/interface/io/displif.h
> index 18417b017869..60e42d3b760e 100644
> --- a/include/xen/interface/io/displif.h
> +++ b/include/xen/interface/io/displif.h
> @@ -537,7 +537,7 @@ struct xendispl_dbuf_create_req {
>
> struct xendispl_page_directory {
> grant_ref_t gref_dir_next_page;
> - grant_ref_t gref[1]; /* Variable length */
> + grant_ref_t gref[];
> };
>
> /*
> diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h
> index ba4c4274b714..4fef1efcdcab 100644
> --- a/include/xen/interface/io/ring.h
> +++ b/include/xen/interface/io/ring.h
> @@ -95,7 +95,7 @@ struct __name##_sring { \
> RING_IDX req_prod, req_event; \
> RING_IDX rsp_prod, rsp_event; \
> uint8_t __pad[48]; \
> - union __name##_sring_entry ring[1]; /* variable-length */ \
> + union __name##_sring_entry ring[]; \
> }; \
> \
> /* "Front" end's private variables */ \
> diff --git a/include/xen/interface/io/sndif.h b/include/xen/interface/io/sndif.h
> index 445657cdb1de..b818517588b5 100644
> --- a/include/xen/interface/io/sndif.h
> +++ b/include/xen/interface/io/sndif.h
> @@ -659,7 +659,7 @@ struct xensnd_open_req {
>
> struct xensnd_page_directory {
> grant_ref_t gref_dir_next_page;
> - grant_ref_t gref[1]; /* Variable length */
> + grant_ref_t gref[];
> };
>
> /*
> --
> 2.35.3
>