io_uring: fix missing msg_name assignment

Ensure to set msg.msg_name for the async portion of send/recvmsg,
as the header copy will copy to/from it.

Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -3553,6 +3553,7 @@ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (req->flags & REQ_F_NEED_CLEANUP)
 		return 0;
 
+	io->msg.msg.msg_name = &io->msg.addr;
 	io->msg.iov = io->msg.fast_iov;
 	ret = sendmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags,
 					&io->msg.iov);
@@ -3734,6 +3735,7 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
 
 static int io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_ctx *io)
 {
+	io->msg.msg.msg_name = &io->msg.addr;
 	io->msg.iov = io->msg.fast_iov;
 
 #ifdef CONFIG_COMPAT