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| author | Jens Axboe <axboe@kernel.dk> | 2023-06-12 13:51:36 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-06-21 16:00:55 +0200 |
| commit | c9c3163c7ab901fb1f184a821285851534ba46e2 (patch) | |
| tree | 8fb1f568f56aa412b9f76161db5fbc1ae36fd6c5 /io_uring | |
| parent | cffaa97ffb672f41cf27e328479c52a2a32ad683 (diff) | |
| download | linux-c9c3163c7ab901fb1f184a821285851534ba46e2.tar.gz | |
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/net.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/io_uring/net.c b/io_uring/net.c index f6d8b02387a9..05792a689994 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; }; @@ -182,11 +183,15 @@ 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) @@ -284,6 +289,7 @@ 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) |