Re: [PATCH net-next] ip, ip6: Fix splice to raw and ping sockets

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

On Fri, Jun 16, 2023 at 7:23 AM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Wed, 14 Jun 2023 09:04:16 +0100 David Howells wrote:
> > Splicing to SOCK_RAW sockets may set MSG_SPLICE_PAGES, but in such a case,
> > __ip_append_data() will call skb_splice_from_iter() to access the 'from'
> > data, assuming it to point to a msghdr struct with an iter, instead of
> > using the provided getfrag function to access it.
> >
> > In the case of raw_sendmsg(), however, this is not the case and 'from' will
> > point to a raw_frag_vec struct and raw_getfrag() will be the frag-getting
> > function.  A similar issue may occur with rawv6_sendmsg().
> >
> > Fix this by ignoring MSG_SPLICE_PAGES if getfrag != ip_generic_getfrag as
> > ip_generic_getfrag() expects "from" to be a msghdr*, but the other getfrags
> > don't.  Note that this will prevent MSG_SPLICE_PAGES from being effective
> > for udplite.
> >
> > This likely affects ping sockets too.  udplite looks like it should be okay
> > as it expects "from" to be a msghdr.
>
> Willem, looks good?

Reviewed-by: Willem de Bruijn <willemb@google.com>

Disabling splicing if not ip_generic_getfrag sounds great to me.