Re: [PATCH] usb: mon: make mmapped memory read only

[Dmitry Vyukov]

On Mon, 19 Sept 2022 at 06:25, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
>
> Hi Tadeusz,
>
> Looking at places like these:
> https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/infiniband/hw/qib/qib_file_ops.c#L736
> https://elixir.bootlin.com/linux/v6.0-rc5/source/drivers/infiniband/hw/mlx5/main.c#L2088
> I think we also need to remove VM_MAYWRITE, otherwise it's still
> possible to turn it into a writable mapping with mprotect.
>
> It's also probably better to return an error if VM_WRITE (or VM_EXEC?) is set
> rather than silently fix it up.


The credit for the VM_MAYWRITE suggestion goes to the PaX Team.

Suggested-by: PaX Team <pageexec@xxxxxxxxxxx>