lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 01 Oct 2014 20:28:18 +0400 From: Andrey Ryabinin <a.ryabinin@...sung.com> To: "H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org Cc: Dmitry Vyukov <dvyukov@...gle.com>, Konstantin Serebryany <kcc@...gle.com>, Dmitry Chernenkov <dmitryc@...gle.com>, Andrey Konovalov <adech.fo@...il.com>, Yuri Gribov <tetra2005@...il.com>, Konstantin Khlebnikov <koct9i@...il.com>, Sasha Levin <sasha.levin@...cle.com>, Christoph Lameter <cl@...ux.com>, Joonsoo Kim <iamjoonsoo.kim@....com>, Andrew Morton <akpm@...ux-foundation.org>, Dave Hansen <dave.hansen@...el.com>, Andi Kleen <andi@...stfloor.org>, Vegard Nossum <vegard.nossum@...il.com>, x86@...nel.org, linux-mm@...ck.org, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com> Subject: Re: [RFC/PATCH v2 02/10] x86_64: add KASan support On 10/01/2014 07:31 PM, H. Peter Anvin wrote: > On 09/10/2014 10:31 PM, Andrey Ryabinin wrote: >> On 09/11/2014 08:01 AM, H. Peter Anvin wrote: >>> On 09/10/2014 07:31 AM, Andrey Ryabinin wrote: >>>> This patch add arch specific code for kernel address sanitizer. >>>> >>>> 16TB of virtual addressed used for shadow memory. >>>> It's located in range [0xffff800000000000 - 0xffff900000000000] >>>> Therefore PAGE_OFFSET has to be changed from 0xffff880000000000 >>>> to 0xffff900000000000. >>> >>> NAK on this. >>> >>> 0xffff880000000000 is the lowest usable address because we have agreed >>> to leave 0xffff800000000000-0xffff880000000000 for the hypervisor or >>> other non-OS uses. >>> >>> Bumping PAGE_OFFSET seems needlessly messy, why not just designate a >>> zone higher up in memory? >>> >> >> I already answered to Dave why I choose to place shadow bellow PAGE_OFFSET (answer copied bellow). >> In short - yes, shadow could be higher. But for some sort of kernel bugs we could have confusing oopses in kasan kernel. >> > > Confusing how? I presume you are talking about something trying to > touch a non-canonical address, which is usually a very blatant type of bug. > > -hpa > For those kinds of bugs we normally get general protection fault. With inline instrumented kasan we could get either general protection fault, or unhandled page fault on "kasan_mem_to_shadow(non_canonical_address)" address. I assume that the last case could be a bit confusing. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists