Re: [PATCH v2] riscv: define ILLEGAL_POINTER_VALUE for 64bit

[Palmer Dabbelt]

On Fri, 05 Jul 2024 17:50:10 PDT (-0700), jszhang@xxxxxxxxxx wrote:
> On Sat, Jul 06, 2024 at 01:02:10AM +0800, Jisheng Zhang wrote:
> > This is used in poison.h for poison pointer offset. Based on current
> > SV39, SV48 and SV57 vm layout, 0xdead000000000000 is a proper value
> > that is not mappable, this can avoid potentially turning an oops to
> > an expolit.
>
> Maybe I also need to cc stable? This is a secure hole fix patch.

Ya, and I guess it's just been broken forever?  I stuck a

Fixes: fbe934d69eb7 ("RISC-V: Build Infrastructure")

it should show up on for-next, assuming the tests pass...

> > Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
> > ---
> >
> > Since v1:
> >  - fix typo:s/SV59/SV57
> >
> >  arch/riscv/Kconfig | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index c51b32a8ddff..c992eabbd002 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -313,6 +313,11 @@ config GENERIC_HWEIGHT
> >  config FIX_EARLYCON_MEM
> >  	def_bool MMU
> >
> > +config ILLEGAL_POINTER_VALUE
> > +	hex
> > +	default 0 if 32BIT
> > +	default 0xdead000000000000 if 64BIT
> > +
> >  config PGTABLE_LEVELS
> >  	int
> >  	default 5 if 64BIT
> > --
> > 2.43.0
> >
> >
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