io_uring/net: disable partial retries for recvmsg with cmsg

Commit 78d0d2063b upstream.

We cannot sanely handle partial retries for recvmsg if we have cmsg
attached. If we don't, then we'd just be overwriting the initial cmsg
header on retries. Alternatively we could increment and handle this
appropriately, but it doesn't seem worth the complication.

Move the MSG_WAITALL check into the non-multishot case while at it,
since MSG_WAITALL is explicitly disabled for multishot anyway.

Link: https://lore.kernel.org/io-uring/0b0d4411-c8fd-4272-770b-e030af6919a0@kernel.dk/
Cc: stable@vger.kernel.org # 5.10+
Reported-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jens Axboe 2023-06-23 07:41:10 -06:00 committed by Justin Hammond
parent e514c1a06a
commit 1655c46e96

View file

@ -5201,7 +5201,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
flags = req->sr_msg.msg_flags;
if (force_nonblock)
flags |= MSG_DONTWAIT;
if (flags & MSG_WAITALL)
if (flags & MSG_WAITALL && !kmsg->msg.msg_controllen)
min_ret = iov_iter_count(&kmsg->msg.msg_iter);
ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg,