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

[Jakub Kicinski]

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?