Date: Mon, 15 Apr 2013 14:06:33 -0700 From: Eric Northup <digitaleric@...gle.com> To: "H. Peter Anvin" <hpa@...or.com> Cc: Yinghai Lu <yinghai@...nel.org>, Kees Cook <keescook@...omium.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, "kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "the arch/x86 maintainers" <x86@...nel.org>, Jarkko Sakkinen <jarkko.sakkinen@...el.com>, Matthew Garrett <mjg@...hat.com>, Matt Fleming <matt.fleming@...el.com>, Dan Rosenberg <drosenberg@...curity.com>, Julien Tinnes <jln@...gle.com>, Will Drewry <wad@...omium.org> Subject: Re: [PATCH 6/6] x86: kaslr: relocate base offset at boot On Sat, Apr 13, 2013 at 8:06 PM, H. Peter Anvin <hpa@...or.com> wrote: > On 04/13/2013 05:37 PM, Yinghai Lu wrote: >> >> so decompress code position is changed? >> >> You may push out bss and other data area of run-time kernel of limit >> that boot loader >> chose according to setup_header.init_size. >> aka that make those area overlap with ram hole or other area like >> boot command line or initrd.... >> > > Is there a strong reason to randomize the physical address on 64 bits > (and if so, shouldn't we do it right?) The reason to randomize the physical address is because of the kernel direct mapping range -- a predictable-to-attackers physical address implies a predictable-to-attackers virtual address. It had seemed to me like changing the virtual base of the direct mapping would be much more involved than physically relocating the kernel, but better suggestions would be most welcome :-)
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.