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* [RFC PATCH 0/4] net/io_uring: pass a kernel pointer via optlen_t to proto[_ops].getsockopt()
@ 2025-03-31 20:10 Stefan Metzmacher
  2025-03-31 20:10 ` [RFC PATCH 1/4] net: introduce get_optlen() and put_optlen() helpers Stefan Metzmacher
                   ` (5 more replies)
  0 siblings, 6 replies; 28+ messages in thread
From: Stefan Metzmacher @ 2025-03-31 20:10 UTC (permalink / raw)
  To: Linus Torvalds, Jens Axboe
  Cc: Stefan Metzmacher, Pavel Begunkov, Breno Leitao, Jakub Kicinski,
	Christoph Hellwig, Karsten Keil, Ayush Sawal, Andrew Lunn,
	David S. Miller, Eric Dumazet, Paolo Abeni, Simon Horman,
	Kuniyuki Iwashima, Willem de Bruijn, David Ahern,
	Marcelo Ricardo Leitner, Xin Long, Neal Cardwell, Joerg Reuter,
	Marcel Holtmann, Johan Hedberg, Luiz Augusto von Dentz,
	Oliver Hartkopp, Marc Kleine-Budde, Robin van der Gracht,
	Oleksij Rempel, kernel, Alexander Aring, Stefan Schmidt,
	Miquel Raynal, Alexandra Winter, Thorsten Winkler, James Chapman,
	Jeremy Kerr, Matt Johnston, Matthieu Baerts, Mat Martineau,
	Geliang Tang, Krzysztof Kozlowski, Remi Denis-Courmont,
	Allison Henderson, David Howells, Marc Dionne, Wenjia Zhang,
	Jan Karcher, D. Wythe, Tony Lu, Wen Gu, Jon Maloy, Boris Pismenny,
	John Fastabend, Stefano Garzarella, Martin Schiller,
	Björn Töpel, Magnus Karlsson, Maciej Fijalkowski,
	Jonathan Lemon, Alexei Starovoitov, Daniel Borkmann,
	Jesper Dangaard Brouer, netdev, linux-kernel, linux-sctp,
	linux-hams, linux-bluetooth, linux-can, dccp, linux-wpan,
	linux-s390, mptcp, linux-rdma, rds-devel, linux-afs,
	tipc-discussion, virtualization, linux-x25, bpf, isdn4linux,
	io-uring

The motivation for this is to remove the SOL_SOCKET limitation
from io_uring_cmd_getsockopt().

The reason for this limitation is that io_uring_cmd_getsockopt()
passes a kernel pointer as optlen to do_sock_getsockopt()
and can't reach the ops->getsockopt() path.

The first idea would be to change the optval and optlen arguments
to the protocol specific hooks also to sockptr_t, as that
is already used for setsockopt() and also by do_sock_getsockopt()
sk_getsockopt() and BPF_CGROUP_RUN_PROG_GETSOCKOPT().

But as Linus don't like 'sockptr_t' I used a different approach.

@Linus, would that optlen_t approach fit better for you?

Instead of passing the optlen as user or kernel pointer,
we only ever pass a kernel pointer and do the
translation from/to userspace in do_sock_getsockopt().

The simple solution would be to just remove the
'__user' from the int *optlen argument, but it
seems the compiler doesn't complain about
'__user' vs. without it, so instead I used
a helper struct in order to make sure everything
compiles with a typesafe change.

The patchset does the transformation in 3
easy to review steps:

1/4: introduces get_optlen(len, optlen) and put_optlen(len, optlen) helpers
     on top of the existing get_user(len, optlen) and put_user(len, optlen)
     usages.

2/4: introduces a simple optlen_t that just contains 'int __user *up;'
     that makes sure get_optlen and put_optlen get a typesafe optlen argument
     and they are the only functions looking at optlen.
     (The existing sockptr_t optlen code gets OPTLEN_SOCKPTR(optlen) passed)

3/4: The changes do_sock_getsockopt() to pass a kernel pointer instead
     of a __user pointer via optlen_t. This is a bit tricky as
     directly failing the copy_from_sockptr(&koptlen, optlen, sizeof(koptlen)
     with -EFAULT might change the uapi, as some getsockopt() hooks
     doesn't even touch optlen at all. And userspace could do something
     like this:

        feature_x_supported = true;
        ret = getsockopt(fd, level, optname, NULL, NULL);
        if (ret == -1 && errno == ENOTSUPP) {
            feature_x_supported = false;
        }

     And this should not give -EFAULT after the changes,
     so optlen.kp is passed down as NULL, so that -EFAULT is
     deferred to get_optlen() and put_optlen().

4/4: Removes the SOL_SOCKET restriction for io-uring.

This patchset doesn't touch any existing getsockopt() that
was already converted to sockptr_t optlen, that's something
for a later cleanup.

Link: https://lore.kernel.org/io-uring/86b1dce5-4bb4-4a0b-9cff-e72f488bf57d@samba.org/T/#t
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: Ayush Sawal <ayush.sawal@chelsio.com>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: David Ahern <dsahern@kernel.org>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Joerg Reuter <jreuter@yaina.de>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Robin van der Gracht <robin@protonic.nl>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: kernel@pengutronix.de
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Alexandra Winter <wintera@linux.ibm.com>
Cc: Thorsten Winkler <twinkler@linux.ibm.com>
Cc: James Chapman <jchapman@katalix.com>
Cc: Jeremy Kerr <jk@codeconstruct.com.au>
Cc: Matt Johnston <matt@codeconstruct.com.au>
Cc: Matthieu Baerts <matttbe@kernel.org>
Cc: Mat Martineau <martineau@kernel.org>
Cc: Geliang Tang <geliang@kernel.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Remi Denis-Courmont <courmisch@gmail.com>
Cc: Allison Henderson <allison.henderson@oracle.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Wenjia Zhang <wenjia@linux.ibm.com>
Cc: Jan Karcher <jaka@linux.ibm.com>
Cc: "D. Wythe" <alibuda@linux.alibaba.com>
Cc: Tony Lu <tonylu@linux.alibaba.com>
Cc: Wen Gu <guwen@linux.alibaba.com>
Cc: Jon Maloy <jmaloy@redhat.com>
Cc: Boris Pismenny <borisp@nvidia.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Stefano Garzarella <sgarzare@redhat.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Cc: "Björn Töpel" <bjorn@kernel.org>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>
Cc: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Cc: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
CC: Stefan Metzmacher <metze@samba.org>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-sctp@vger.kernel.org
Cc: linux-hams@vger.kernel.org
Cc: linux-bluetooth@vger.kernel.org
Cc: linux-can@vger.kernel.org
Cc: dccp@vger.kernel.org
Cc: linux-wpan@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: mptcp@lists.linux.dev
Cc: linux-rdma@vger.kernel.org
Cc: rds-devel@oss.oracle.com
Cc: linux-afs@lists.infradead.org
Cc: tipc-discussion@lists.sourceforge.net
Cc: virtualization@lists.linux.dev
Cc: linux-x25@vger.kernel.org
Cc: bpf@vger.kernel.org
Cc: isdn4linux@listserv.isdn4linux.de
Cc: io-uring@vger.kernel.org

Stefan Metzmacher (4):
  net: introduce get_optlen() and put_optlen() helpers
  net: pass 'optlen_t' to proto[ops].getsockopt() hooks
  net: pass a kernel pointer via 'optlen_t' to proto[ops].getsockopt()
    hooks
  io_uring: let io_uring_cmd_getsockopt() allow level other than
    SOL_SOCKET

 drivers/isdn/mISDN/socket.c                   |   4 +-
 .../chelsio/inline_crypto/chtls/chtls_main.c  |   4 +-
 include/linux/net.h                           |   2 +-
 include/linux/sockptr.h                       |  41 ++++
 include/net/inet_connection_sock.h            |   2 +-
 include/net/ip.h                              |   2 +-
 include/net/ipv6.h                            |   2 +-
 include/net/sctp/structs.h                    |   2 +-
 include/net/sock.h                            |   4 +-
 include/net/tcp.h                             |   2 +-
 include/net/udp.h                             |   2 +-
 io_uring/uring_cmd.c                          |   3 -
 net/atm/common.c                              |   4 +-
 net/atm/common.h                              |   2 +-
 net/atm/pvc.c                                 |   2 +-
 net/atm/svc.c                                 |   4 +-
 net/ax25/af_ax25.c                            |   6 +-
 net/bluetooth/hci_sock.c                      |   6 +-
 net/bluetooth/iso.c                           |   6 +-
 net/bluetooth/l2cap_sock.c                    |   8 +-
 net/bluetooth/rfcomm/sock.c                   |   8 +-
 net/bluetooth/sco.c                           |  10 +-
 net/can/isotp.c                               |   6 +-
 net/can/j1939/socket.c                        |   6 +-
 net/can/raw.c                                 |  14 +-
 net/core/sock.c                               |   2 +-
 net/dccp/ccid.c                               |   4 +-
 net/dccp/ccid.h                               |  10 +-
 net/dccp/ccids/ccid3.c                        |   8 +-
 net/dccp/dccp.h                               |   2 +-
 net/dccp/proto.c                              |  12 +-
 net/ieee802154/socket.c                       |   8 +-
 net/ipv4/ip_sockglue.c                        |   8 +-
 net/ipv4/raw.c                                |  10 +-
 net/ipv4/tcp.c                                |   4 +-
 net/ipv4/udp.c                                |   8 +-
 net/ipv4/udp_impl.h                           |   2 +-
 net/ipv6/ipv6_sockglue.c                      |   8 +-
 net/ipv6/raw.c                                |  14 +-
 net/ipv6/udp.c                                |   2 +-
 net/ipv6/udp_impl.h                           |   2 +-
 net/iucv/af_iucv.c                            |   6 +-
 net/kcm/kcmsock.c                             |   6 +-
 net/l2tp/l2tp_ppp.c                           |   6 +-
 net/llc/af_llc.c                              |   6 +-
 net/mctp/af_mctp.c                            |   4 +-
 net/mptcp/protocol.h                          |   2 +-
 net/mptcp/sockopt.c                           |  48 ++--
 net/netlink/af_netlink.c                      |   8 +-
 net/netrom/af_netrom.c                        |   6 +-
 net/nfc/llcp_sock.c                           |   6 +-
 net/packet/af_packet.c                        |   6 +-
 net/phonet/pep.c                              |   6 +-
 net/rds/af_rds.c                              |   8 +-
 net/rds/info.c                                |   6 +-
 net/rds/info.h                                |   2 +-
 net/rose/af_rose.c                            |   6 +-
 net/rxrpc/af_rxrpc.c                          |   6 +-
 net/sctp/socket.c                             | 220 +++++++++---------
 net/smc/af_smc.c                              |   8 +-
 net/smc/smc.h                                 |   2 +-
 net/socket.c                                  |  34 ++-
 net/tipc/socket.c                             |   8 +-
 net/tls/tls_main.c                            |  18 +-
 net/vmw_vsock/af_vsock.c                      |   6 +-
 net/x25/af_x25.c                              |   6 +-
 net/xdp/xsk.c                                 |  10 +-
 67 files changed, 387 insertions(+), 319 deletions(-)

-- 
2.34.1


^ permalink raw reply	[flat|nested] 28+ messages in thread
end of thread, other threads:[~2025-04-02 23:39 UTC | newest]

Thread overview: 28+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-03-31 20:10 [RFC PATCH 0/4] net/io_uring: pass a kernel pointer via optlen_t to proto[_ops].getsockopt() Stefan Metzmacher
2025-03-31 20:10 ` [RFC PATCH 1/4] net: introduce get_optlen() and put_optlen() helpers Stefan Metzmacher
2025-04-01 12:17   ` Breno Leitao
2025-04-01 12:22     ` Stefan Metzmacher
2025-03-31 20:10 ` [RFC PATCH 2/4] net: pass 'optlen_t' to proto[ops].getsockopt() hooks Stefan Metzmacher
2025-03-31 20:27   ` Stefan Metzmacher
2025-03-31 20:10 ` [RFC PATCH 3/4] net: pass a kernel pointer via " Stefan Metzmacher
2025-03-31 21:49   ` David Laight
2025-04-01  8:24     ` Stefan Metzmacher
2025-03-31 20:10 ` [RFC PATCH 4/4] io_uring: let io_uring_cmd_getsockopt() allow level other than SOL_SOCKET Stefan Metzmacher
2025-03-31 21:04 ` [RFC PATCH 0/4] net/io_uring: pass a kernel pointer via optlen_t to proto[_ops].getsockopt() Stanislav Fomichev
2025-04-01  8:19   ` Stefan Metzmacher
2025-04-01 13:37     ` Stefan Metzmacher
2025-04-01 13:48       ` Stefan Metzmacher
2025-04-01 15:35         ` Breno Leitao
2025-04-01 15:45           ` Stanislav Fomichev
2025-04-01 21:20             ` Stefan Metzmacher
2025-04-01 22:04               ` Stanislav Fomichev
2025-04-01 22:53                 ` Stefan Metzmacher
2025-04-02 12:29                   ` David Laight
2025-04-02 14:19                     ` Stanislav Fomichev
2025-04-02 20:46                       ` David Laight
2025-04-02 21:07                         ` Linus Torvalds
2025-04-02 21:21                         ` Stanislav Fomichev
2025-04-02 22:38                           ` David Laight
2025-04-02 23:39                             ` Stanislav Fomichev
2025-04-02  0:40 ` Linus Torvalds
2025-04-02 12:35   ` David Laight

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