Re: [PATCH v13 0/2] arm64: Enable BTI for the executable as well as the interpreter

Kees Cook
2022-04-20T16:49:01Z

On Wed, Apr 20, 2022 at 10:36:13AM +0100, Will Deacon wrote:
> On Tue, Apr 19, 2022 at 10:33:06PM -0700, Kees Cook wrote:
> > On Tue, 19 Apr 2022 11:51:54 +0100, Mark Brown wrote:
> > > Deployments of BTI on arm64 have run into issues interacting with
> > > systemd's MemoryDenyWriteExecute feature. Currently for dynamically
> > > linked executables the kernel will only handle architecture specific
> > > properties like BTI for the interpreter, the expectation is that the
> > > interpreter will then handle any properties on the main executable.
> > > For BTI this means remapping the executable segments PROT_EXEC |
> > > PROT_BTI.
> > >
> > > [...]
> >
> > Applied to for-next/execve, thanks!
> >
> > [1/2] elf: Allow architectures to parse properties on the main executable
> > https://git.kernel.org/kees/c/b2f2553c8e89
> > [2/2] arm64: Enable BTI for main executable as well as the interpreter
> > https://git.kernel.org/kees/c/b65c760600e2
>
> Kees, please can you drop this series while Catalin's alternative solution
> is under discussion (his Reviewed-by preceded the other patches)?
>
> https://lore.kernel.org/r/20220413134946.2732468-1-catalin.marinas@arm.com
>
> Both series expose new behaviours to userspace and we don't need both.

Ah-ha! I wasn't sure if they were solving the same problem or not.

--
Kees Cook