Re: [RFC PATCH v1 0/5] Add support for O_MAYEXEC

From: Matthew Wilcox
Date: Wed Dec 12 2018 - 22:02:36 EST

On Wed, Dec 12, 2018 at 09:17:07AM +0100, Mickaël Salaün wrote:
> The goal of this patch series is to control script interpretation. A
> new O_MAYEXEC flag used by sys_open() is added to enable userland script
> interpreter to delegate to the kernel (and thus the system security
> policy) the permission to interpret scripts or other files containing
> what can be seen as commands.

I don't have a problem with the concept, but we're running low on O_ bits.
Does this have to be done before the process gets a file descriptor,
or could we have a new syscall? Since we're going to be changing the
interpreters anyway, it doesn't seem like too much of an imposition to
ask them to use:

int verify_for_exec(int fd)

instead of adding an O_MAYEXEC.