linux-kernel - Re: [Xen-devel] kasan_map_early

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 3 Mar 2015 10:06:53 +0000
From:	David Vrabel <david.vrabel@...rix.com>
To:	"Luis R. Rodriguez" <mcgrof@...e.com>,
	Andrey Ryabinin <a.ryabinin@...sung.com>
CC:	Jeremy Fitzhardinge <jeremy@...p.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andy Lutomirski <luto@...capital.net>,
	Chris Wright <chrisw@...s-sol.org>,
	<xen-devel@...ts.xenproject.org>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	<virtualization@...ts.linux-foundation.org>,
	Alok Kataria <akataria@...are.com>
Subject: Re: [Xen-devel] kasan_map_early_shadow() on Xen

On 03/03/15 09:40, Luis R. Rodriguez wrote:
> Andrey,
> 
> I believe that on Xen we should disable kasan, would like confirmation

Why?  This is the first of heard of this.

> from someone on xen-devel though. Here's the thing though -- if true
> -- I'd like to do it *properly*, where *properly* means addressing a
> bit of architecture. A simple Kconfig slap seems rather reactive. I'd
> like to address a way to properly ensure we don't run into this and
> other similar issues in the future. The CR4 shadow issue was another
> recent example issue, also introduced via v4.0 [0]. We can't keep
> doing this reactively.
> 
> Let's go down the rabbit hole for a bit. HAVE_ARCH_KASAN will be
> selected on x86 when:
> 
> if X86_64 && SPARSEMEM_VMEMMAP
> 
> Now Xen should not have SPARSEMEM_VMEMMAP but PVOPs' goal is to enable

Why?  Again, this is the first I've heard of this as well.  FWIW, all
the Xen configs we use have SPARSEMEM_VMEMMAP enabled.

David

> distributions to be able to have a single binary kernels and let the
> rest be figured out, so we can't just disable SPARSEMEM_VMEMMAP for
> Xen alone, we want to build Xen.. or part of Xen and perhaps keep
> SPARSEMEM_VMEMMAP, and only later figure things out.
> 
> How do we do this cleanly and avoid future reactive measures? If the
> answer is not upon us, I'd like to at least highlight the issue so
> that in case we do come up with something its no surprise PVOPs is
> falling short for that single binary pipe dream right now.
> 
> [0] https://lkml.org/lkml/2015/2/23/328
> 
>  Luis
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@...ts.xen.org
> http://lists.xen.org/xen-devel
> 

--
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/