io_uring/net: don't update msg_name if not provided

io_sendmsg_copy_hdr() may clear msg->msg_name if the userspace didn't
provide it, we should retain NULL in this case.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/97d49f61b5ec76d0900df658cfde3aa59ff22121.1664486545.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/net.c b/io_uring/net.c
index 9ada9da..604eac5 100644 (file)
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -164,7 +164,8 @@ static int io_setup_async_msg(struct io_kiocb *req,
        }
        req->flags |= REQ_F_NEED_CLEANUP;
        memcpy(async_msg, kmsg, sizeof(*kmsg));
-       async_msg->msg.msg_name = &async_msg->addr;
+       if (async_msg->msg.msg_name)
+               async_msg->msg.msg_name = &async_msg->addr;
        /* if were using fast_iov, set it to the new one */
        if (!kmsg->free_iov) {
                size_t fast_idx = kmsg->msg.msg_iter.iov - kmsg->fast_iov;