diff options
| author | Jens Axboe <axboe@kernel.dk> | 2023-06-23 16:38:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-06-28 11:28:09 +0300 |
| commit | 5fdea4468f57db3fc304e366d03d7214ca3a209e (patch) | |
| tree | e24ca5003db169d4ded12f1b5b21f23aaa8e8e64 /io_uring | |
| parent | 5a7101d8faab97fb1e258b134c2afc1ccad9c2d9 (diff) | |
| download | linux-5fdea4468f57db3fc304e366d03d7214ca3a209e.tar.xz | |
io_uring/net: save msghdr->msg_control for retries
Commit cac9e4418f4cbd548ccb065b3adcafe073f7f7d2 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 58e063114398..1a76659659cf 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -581,6 +581,7 @@ struct io_sr_msg { size_t len; size_t done_io; struct io_buffer *kbuf; + void __user *msg_control; }; struct io_open { @@ -4718,10 +4719,16 @@ static int io_setup_async_msg(struct io_kiocb *req, static int io_sendmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { + struct io_sr_msg *sr = &req->sr_msg; + int ret; + iomsg->msg.msg_name = &iomsg->addr; iomsg->free_iov = iomsg->fast_iov; - return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg, + ret = sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg, req->sr_msg.msg_flags, &iomsg->free_iov); + /* save msg_control as sys_sendmsg() overwrites it */ + sr->msg_control = iomsg->msg.msg_control; + return ret; } static int io_sendmsg_prep_async(struct io_kiocb *req) @@ -4778,6 +4785,8 @@ static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags) if (ret) return ret; kmsg = &iomsg; + } else { + kmsg->msg.msg_control = sr->msg_control; } flags = req->sr_msg.msg_flags; |