Re: [PATCH 5.10.y 1/2] arm64: Always load shadow stack pointer directly from the task struct

[Greg KH <gregkh@linuxfoundation.org>]

On Sun, May 07, 2023 at 10:11:32AM +0200, Ard Biesheuvel wrote:
> On Sun, 7 May 2023 at 07:11, Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > On Sat, May 06, 2023 at 02:34:33PM +0200, Ard Biesheuvel wrote:
> > > All occurrences of the scs_load macro load the value of the shadow call
> > > stack pointer from the task which is current at that point. So instead
> > > of taking a task struct register argument in the scs_load macro to
> > > specify the task struct to load from, let's always reference the current
> > > task directly. This should make it much harder to exploit any
> > > instruction sequences reloading the shadow call stack pointer register
> > > from memory.
> > >
> > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> > > Acked-by: Mark Rutland <mark.rutland@arm.com>
> > > Reviewed-by: Kees Cook <keescook@chromium.org>
> > > Link: https://lore.kernel.org/r/20230109174800.3286265-2-ardb@kernel.org
> > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> > > ---
> > >  arch/arm64/include/asm/scs.h | 7 ++++---
> > >  arch/arm64/kernel/entry.S    | 4 ++--
> > >  arch/arm64/kernel/head.S     | 2 +-
> > >  3 files changed, 7 insertions(+), 6 deletions(-)
> >
> > What is the git commit id of this in Linus's tree?
> >
> 
> commit 2198d07c509f1db4a1185d1f65aaada794c6ea59 upstream.

Thanks, both now queued up!

greg k-h