Re: [PATCH 2/5] x86, KASLR: Drop CONFIG_RANDOMIZE_BASE_MAX_OFFSET

2016-04-22 Thread Borislav Petkov
On Fri, Apr 22, 2016 at 09:16:12AM +0200, Ingo Molnar wrote: > > * Kees Cook wrote: > > > >> + Since the kernel is built using 2GB addressing, > > > > > > Does that try to refer to the 1G kernel and 1G fixmap pagetable > > > mappings? I.e., level2_kernel_pgt and level2_fixmap_pgt in > > >

Re: [PATCH 2/5] x86, KASLR: Drop CONFIG_RANDOMIZE_BASE_MAX_OFFSET

2016-04-22 Thread Ingo Molnar
* Kees Cook wrote: > >> + Since the kernel is built using 2GB addressing, > > > > Does that try to refer to the 1G kernel and 1G fixmap pagetable > > mappings? I.e., level2_kernel_pgt and level2_fixmap_pgt in > > arch/x86/kernel/head_64.S? > > The "2GB addressing" part is in reference to:

Re: [PATCH 2/5] x86, KASLR: Drop CONFIG_RANDOMIZE_BASE_MAX_OFFSET

2016-04-21 Thread Kees Cook
On Thu, Apr 21, 2016 at 10:44 AM, Borislav Petkov wrote: > On Wed, Apr 20, 2016 at 01:55:43PM -0700, Kees Cook wrote: >> From: Baoquan He >> >> Currently CONFIG_RANDOMIZE_BASE_MAX_OFFSET is used to limit the maximum >> offset for kernel randomization. This limit doesn't need to be a CONFIG >> sin

Re: [PATCH 2/5] x86, KASLR: Drop CONFIG_RANDOMIZE_BASE_MAX_OFFSET

2016-04-21 Thread Borislav Petkov
On Wed, Apr 20, 2016 at 01:55:43PM -0700, Kees Cook wrote: > From: Baoquan He > > Currently CONFIG_RANDOMIZE_BASE_MAX_OFFSET is used to limit the maximum > offset for kernel randomization. This limit doesn't need to be a CONFIG > since it is tied completely to KERNEL_IMAGE_SIZE, and will make no

[PATCH 2/5] x86, KASLR: Drop CONFIG_RANDOMIZE_BASE_MAX_OFFSET

2016-04-20 Thread Kees Cook
From: Baoquan He Currently CONFIG_RANDOMIZE_BASE_MAX_OFFSET is used to limit the maximum offset for kernel randomization. This limit doesn't need to be a CONFIG since it is tied completely to KERNEL_IMAGE_SIZE, and will make no sense once physical and virtual offsets are randomized separately. Th