Messages in this thread | | | From | Alex Ghiti <> | Subject | Re: [PATCH v3 04/11] arm64, mm: Move generic mmap layout functions to mm | Date | Fri, 19 Apr 2019 09:20:36 +0200 |
| |
On 4/18/19 10:19 AM, Kees Cook wrote: > On Thu, Apr 18, 2019 at 12:55 AM Alex Ghiti <alex@ghiti.fr> wrote: >> Regarding the help text, I agree that it does not seem to be frequent to >> place >> comment above config like that, I'll let Christoph and you decide what's >> best. And I'll >> add the possibility for the arch to define its own STACK_RND_MASK. > Yeah, I think it's very helpful to spell out the requirements for new > architectures with these kinds of features in the help text (see > SECCOMP_FILTER for example). > >>> I think CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT should select >>> CONFIG_ARCH_HAS_ELF_RANDOMIZE. It would mean moving >> >> I don't think we should link those 2 features together: an architecture >> may want >> topdown mmap and don't care about randomization right ? > Given that the mmap randomization and stack randomization are already > coming along for the ride, it seems weird to make brk randomization an > optional feature (especially since all the of the architectures you're > converting include it). I'd also like these kinds of security features > to be available by default. So, I think one patch to adjust the MIPS > brk randomization entropy and then you can just include it in this > move.
Ok that makes sense, and that would bring support for randomization to riscv at the same time, so I'll look into it, thanks.
>> Actually, I had to add those ifdefs for mmap_rnd_compat_bits, not >> is_compat_task. > Oh! In that case, use CONFIG_HAVE_ARCH_MMAP_RND_BITS. :) Actually, > what would be maybe cleaner would be to add mmap_rnd_bits_min/max > consts set to 0 for the non-CONFIG_HAVE_ARCH_MMAP_RND_BITS case at the > top of mm/mmap.c.
Ok I'll do that.
> > I really like this clean-up! I think we can move x86 to it too without > too much pain. :) >
Yeah I think too, I will do that too.
Thanks again,
Alex
| |