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Date: Tue, 9 Aug 2016 09:00:04 -0700
From: Thomas Garnier <thgarnie@...gle.com>
To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...e.de>, Joerg Roedel <jroedel@...e.de>,
Dave Young <dyoung@...hat.com>, "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
Lv Zheng <lv.zheng@...el.com>, Thomas Garnier <thgarnie@...gle.com>, Baoquan He <bhe@...hat.com>,
Dave Hansen <dave.hansen@...ux.intel.com>, Mark Salter <msalter@...hat.com>,
Aleksey Makarov <aleksey.makarov@...aro.org>, Kees Cook <keescook@...omium.org>,
Andrew Morton <akpm@...ux-foundation.org>, Christian Borntraeger <borntraeger@...ibm.com>,
Fabian Frederick <fabf@...net.be>, Toshi Kani <toshi.kani@...com>,
Dan Williams <dan.j.williams@...el.com>
Cc: "the arch/x86 maintainers" <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
Kernel Hardening <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH v1 1/2] x86/KASLR: Fix physical memory calculation on
KASLR memory randomization
On Mon, Aug 8, 2016 at 11:40 AM, Thomas Garnier <thgarnie@...gle.com> wrote:
> Initialize KASLR memory randomization after max_pfn is initialized. Also
> ensure the size is rounded up. Could have create problems on machines
> with more than 1Tb of memory on certain random addresses.
>
> Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
I will send a new version of this PATCH soon. The test bot found
places where virtual addresses were computed before PAGE_OFFSET was
set. I will investigate that.
> ---
> Based on next-20160805
> ---
> arch/x86/kernel/setup.c | 4 ++--
> arch/x86/mm/kaslr.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index bcabb88..8dda0ce 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -936,8 +936,6 @@ void __init setup_arch(char **cmdline_p)
>
> x86_init.oem.arch_setup();
>
> - kernel_randomize_memory();
> -
> iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
> setup_memory_map();
> parse_setup_data();
> @@ -1071,6 +1069,8 @@ void __init setup_arch(char **cmdline_p)
> high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
> #endif
>
> + kernel_randomize_memory();
> +
> /*
> * Find and reserve possible boot-time SMP configuration:
> */
> diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
> index 26dccd6..ec8654f 100644
> --- a/arch/x86/mm/kaslr.c
> +++ b/arch/x86/mm/kaslr.c
> @@ -97,7 +97,7 @@ void __init kernel_randomize_memory(void)
> * add padding if needed (especially for memory hotplug support).
> */
> BUG_ON(kaslr_regions[0].base != &page_offset_base);
> - memory_tb = ((max_pfn << PAGE_SHIFT) >> TB_SHIFT) +
> + memory_tb = DIV_ROUND_UP(max_pfn << PAGE_SHIFT, 1UL << TB_SHIFT) +
> CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING;
>
> /* Adapt phyiscal memory region size based on available memory */
> --
> 2.8.0.rc3.226.g39d4020
>
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