io_uring/net: save msghdr->msg_control for retries
commit cac9e4418f
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>
This commit is contained in:
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@ -65,6 +65,7 @@ struct io_sr_msg {
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u16 addr_len;
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u16 addr_len;
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u16 buf_group;
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u16 buf_group;
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void __user *addr;
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void __user *addr;
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void __user *msg_control;
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/* used only for send zerocopy */
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/* used only for send zerocopy */
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struct io_kiocb *notif;
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struct io_kiocb *notif;
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};
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};
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@ -182,11 +183,15 @@ static int io_sendmsg_copy_hdr(struct io_kiocb *req,
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struct io_async_msghdr *iomsg)
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struct io_async_msghdr *iomsg)
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{
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{
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struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
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struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
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int ret;
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iomsg->msg.msg_name = &iomsg->addr;
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iomsg->msg.msg_name = &iomsg->addr;
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iomsg->free_iov = iomsg->fast_iov;
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iomsg->free_iov = iomsg->fast_iov;
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return sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags,
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ret = sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags,
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&iomsg->free_iov);
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&iomsg->free_iov);
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/* save msg_control as sys_sendmsg() overwrites it */
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sr->msg_control = iomsg->msg.msg_control;
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return ret;
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}
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}
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int io_send_prep_async(struct io_kiocb *req)
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int io_send_prep_async(struct io_kiocb *req)
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@ -284,6 +289,7 @@ int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
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if (req_has_async_data(req)) {
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if (req_has_async_data(req)) {
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kmsg = req->async_data;
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kmsg = req->async_data;
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kmsg->msg.msg_control = sr->msg_control;
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} else {
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} else {
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ret = io_sendmsg_copy_hdr(req, &iomsg);
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ret = io_sendmsg_copy_hdr(req, &iomsg);
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if (ret)
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if (ret)
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