Re: [PATCH net-next] modules: allow modprobe load regular elf binaries

[Kees Cook]

On Fri, Mar 9, 2018 at 10:35 AM, David Miller <davem@xxxxxxxxxxxxx> wrote:
> From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Date: Fri, 9 Mar 2018 10:17:42 -0800
>
>>  - use deny_write_access() to make sure that we don't have active
>> writers and cannot get them during the execve.
>
> I agree that this is necessary for image validation purposes.

Module loading (via kernel_read_file()) already uses
deny_write_access(), and so does do_open_execat(). As long as module
loading doesn't call allow_write_access() before the execve() has
started in the new implementation, I think we'd be covered here.

-Kees

-- 
Kees Cook
Pixel Security