Re: File operations

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

On Mon, Dec 14, 2020 at 3:03 AM Wedson Almeida Filho
<wedsonaf@google.com> wrote:
>
> But one potential issue that comes immediately to mind is that with a
> builder pattern, the value is created at run time. In our case, this
> is undesirable because this table contains function pointers: if we
> leave them in writable memory, they will become easy targets when
> attackers have write-vulnerabilities that they want to elevate to
> arbitrary execution; leaving the vtable in rdata (i.e., in read-only
> pages) is much preferable. This means that we need const functions,
> but we cannot have them in traits.

That's true, I was assuming the optimizer would realize it is a
compile-time value anyway, so that we could do it that way even
without using `const` etc.

> If we are ok with repeating function names, I have a solution with a
> much simpler macro. Of course, it is simple enough that clients can
> just ignore it and define the const themselves if they want to avoid
> macros at all costs. What do you think of
> https://github.com/Rust-for-Linux/linux/commit/13b2f2c47e62ad5bf824f7e15e14090c90a4ba9e
> ?

That looks quite good to me! It seems easy to use, and the
implementation is also easier to understand.

Cheers,
Miguel