diff options
| author | Jens Axboe <axboe@kernel.dk> | 2023-06-12 13:51:36 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-06-13 19:26:42 -0600 |
| commit | cac9e4418f4cbd548ccb065b3adcafe073f7f7d2 (patch) | |
| tree | ef49d2c9a2399b2b577b11261cfd3618a588e345 | |
| parent | b6dad5178ceaf23f369c3711062ce1f2afc33644 (diff) | |
| download | linux-cac9e4418f4cbd548ccb065b3adcafe073f7f7d2.tar.gz | |
io_uring/net: save msghdr->msg_control for retries
If the application sets ->msg_control and we have to later retry this
command, or if it got queued with IOSQE_ASYNC to begin with, then we
need to retain the original msg_control value. This is due to the net
stack overwriting this field with an in-kernel pointer, to copy it
in. Hitting that path for the second time will now fail the copy from
user, as it's attempting to copy from a non-user address.
Cc: stable@vger.kernel.org # 5.10+
Link: https://github.com/axboe/liburing/issues/880
Reported-and-tested-by: Marek Majkowski <marek@cloudflare.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | io_uring/net.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/io_uring/net.c b/io_uring/net.c index 89e839013837ff..51b0f7fbb4f542 100644 --- a/io_uring/net.c +++ b/io_uring/net.c @@ -65,6 +65,7 @@ struct io_sr_msg { u16 addr_len; u16 buf_group; void __user *addr; + void __user *msg_control; /* used only for send zerocopy */ struct io_kiocb *notif; }; @@ -195,11 +196,15 @@ static int io_sendmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg); + int ret; iomsg->msg.msg_name = &iomsg->addr; iomsg->free_iov = iomsg->fast_iov; - return sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags, + ret = sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags, &iomsg->free_iov); + /* save msg_control as sys_sendmsg() overwrites it */ + sr->msg_control = iomsg->msg.msg_control; + return ret; } int io_send_prep_async(struct io_kiocb *req) @@ -297,6 +302,7 @@ int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags) if (req_has_async_data(req)) { kmsg = req->async_data; + kmsg->msg.msg_control = sr->msg_control; } else { ret = io_sendmsg_copy_hdr(req, &iomsg); if (ret) |