| Message ID | 20230531124528.699123-3-dhowells@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | splice, net: Handle MSG_SPLICE_PAGES in AF_TLS | expand |
On Wed, May 31, 2023 at 01:45:24PM +0100, David Howells wrote: > It is necessary to allow MSG_SENDPAGE_* to be passed into ->sendmsg() to > allow sendmsg(MSG_SPLICE_PAGES) to replace ->sendpage(). Unblocking them > in the network protocol, however, allows these flags to be passed in by > userspace too[1]. > > Fix this by marking MSG_SENDPAGE_NOPOLICY, MSG_SENDPAGE_NOTLAST and > MSG_SENDPAGE_DECRYPTED as internal flags, which causes sendmsg() to object > if they are passed to sendmsg() by userspace. Network protocol ->sendmsg() > implementations can then allow them through. > > Note that it should be possible to remove MSG_SENDPAGE_NOTLAST once > sendpage is removed as a whole slew of pages will be passed in in one go by Hi David, on the off-chance that you need to respin for some other reason: s/in in/in/ > splice through sendmsg, with MSG_MORE being set if it has more data waiting > in the pipe. ...
diff --git a/include/linux/socket.h b/include/linux/socket.h index bd1cc3238851..3fd3436bc09f 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -339,7 +339,9 @@ struct ucred { #endif /* Flags to be cleared on entry by sendmsg and sendmmsg syscalls */ -#define MSG_INTERNAL_SENDMSG_FLAGS (MSG_SPLICE_PAGES) +#define MSG_INTERNAL_SENDMSG_FLAGS \ + (MSG_SPLICE_PAGES | MSG_SENDPAGE_NOPOLICY | MSG_SENDPAGE_NOTLAST | \ + MSG_SENDPAGE_DECRYPTED) /* Setsockoptions(2) level. Thanks to BSD these must match IPPROTO_xxx */ #define SOL_IP 0
It is necessary to allow MSG_SENDPAGE_* to be passed into ->sendmsg() to allow sendmsg(MSG_SPLICE_PAGES) to replace ->sendpage(). Unblocking them in the network protocol, however, allows these flags to be passed in by userspace too[1]. Fix this by marking MSG_SENDPAGE_NOPOLICY, MSG_SENDPAGE_NOTLAST and MSG_SENDPAGE_DECRYPTED as internal flags, which causes sendmsg() to object if they are passed to sendmsg() by userspace. Network protocol ->sendmsg() implementations can then allow them through. Note that it should be possible to remove MSG_SENDPAGE_NOTLAST once sendpage is removed as a whole slew of pages will be passed in in one go by splice through sendmsg, with MSG_MORE being set if it has more data waiting in the pipe. Signed-off-by: David Howells <dhowells@redhat.com> cc: Jakub Kicinski <kuba@kernel.org> cc: Chuck Lever <chuck.lever@oracle.com> cc: Boris Pismenny <borisp@nvidia.com> cc: John Fastabend <john.fastabend@gmail.com> cc: Eric Dumazet <edumazet@google.com> cc: "David S. Miller" <davem@davemloft.net> cc: Paolo Abeni <pabeni@redhat.com> cc: Jens Axboe <axboe@kernel.dk> cc: Matthew Wilcox <willy@infradead.org> cc: netdev@vger.kernel.org Link: https://lore.kernel.org/r/20230526181338.03a99016@kernel.org/ [1] --- include/linux/socket.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)