[PATCH] proc: allow restricting /proc/pid/mem writes

[Kees Cook]

On Mon, Feb 26, 2024 at 02:37:29PM -0800, Doug Anderson wrote:
> Hi,
> 
> On Mon, Feb 26, 2024 at 2:33 PM Adrian Ratiu <adrian.ratiu at collabora.com> wrote:
> >
> > > > [...]
> > > > +config SECURITY_PROC_MEM_RESTRICT_WRITES
> > >
> > > Instead of a build-time CONFIG, I'd prefer a boot-time config (or a
> > > sysctl, but that's be harder given the perms). That this is selectable
> > > by distro users, etc, and they don't need to rebuild their kernel to
> > > benefit from it.
> >
> > Ack, I'll implement a cmdline arg in v2.
> 
> Any objections to doing both? Have a CONFIG option for a default and a
> cmdline to override it? This way if a distro wants to restrict writes
> by default then don't need to jam more stuff into the kernel command
> line.

For an example, take a look at randomize_kstack_offset and
CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT.

-- 
Kees Cook