Hi Dmitry, On 9/18/22 21:25, Dmitry Vyukov 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.
Yes, I think that returning an error will make more sense here. I don't think we need to worry about VM_EXEC. Even if userspace will try to execute from the mmaped location it won't work. It will probably crash the application without causing any harm to the kernel. I will update the patch and send a v2 soon. -- Thanks, Tadeusz
