On Sat, 2017-04-08 at 20:36 +0200, Steffen Klassert wrote:
> All available gso_type flags are currently in use, so
> extend gso_type from 'unsigned short' to 'unsigned int'
> to be able to add further flags.
>
> We reorder the struct skb_shared_info to use
> two bytes of the four byte hole before dataref.
> All fields before dataref are cleared, i.e.
> four bytes more than before the change.
>
> The remaining two byte hole is moved to the
> beginning of the structure, this protects us
> from immediate overwites on out of bound writes
> to the sk_buff head.
> Signed-off-by: Steffen Klassert <steffen.klass...@secunet.com>
> ---
> include/linux/skbuff.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index c776abd..741d75c 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -413,14 +413,15 @@ struct ubuf_info {
> * the end of the header data, ie. at skb->end.
> */
> struct skb_shared_info {
> + unsigned short _unused;
> unsigned char nr_frags;
> __u8 tx_flags;
> unsigned short gso_size;
> /* Warning: this field is not always filled in (UFO)! */
> unsigned short gso_segs;
> - unsigned short gso_type;
> struct sk_buff *frag_list;
> struct skb_shared_hwtstamps hwtstamps;
> + unsigned int gso_type;
> u32 tskey;
> __be32 ip6_frag_id;
>
This looks much better, thanks Steffen.
Acked-by: Eric Dumazet <eduma...@google.com>
