linux-kernel - Re: [PATCHv2 2/6] x86, mpx: do not set ->vm

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] [day] [month] [year] [list]

Message-ID: <20150723210856.GA26354@node.dhcp.inet.fi>
Date:	Fri, 24 Jul 2015 00:08:56 +0300
From:	"Kirill A. Shutemov" <kirill@...temov.name>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Oleg Nesterov <oleg@...hat.com>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Andy Lutomirski <luto@...capital.net>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCHv2 2/6] x86, mpx: do not set ->vm_ops on mpx VMAs

On Thu, Jul 23, 2015 at 01:59:11PM -0700, Andrew Morton wrote:
> On Fri, 17 Jul 2015 14:53:09 +0300 "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> wrote:
> 
> > MPX setups private anonymous mapping, but uses vma->vm_ops too.
> > This can confuse core VM, as it relies on vm->vm_ops to distinguish
> > file VMAs from anonymous.
> > 
> > As result we will get SIGBUS, because handle_pte_fault() thinks it's
> > file VMA without vm_ops->fault and it doesn't know how to handle the
> > situation properly.
> > 
> > Let's fix that by not setting ->vm_ops.
> > 
> > We don't really need ->vm_ops here: MPX VMA can be detected with VM_MPX
> > flag. And vma_merge() will not merge MPX VMA with non-MPX VMA, because
> > ->vm_flags won't match.
> > 
> > The only thing left is name of VMA. I'm not sure if it's part of ABI, or
> > we can just drop it. The patch keep it by providing arch_vma_name() on x86.
> > 
> > Build tested only.
> 
> mpx.c has changed.
> 
> arch/x86/mm/mpx.c: In function 'try_unmap_single_bt':
> arch/x86/mm/mpx.c:930: error: implicit declaration of function 'is_mpx_vma'
> 
> I'll drop this patch and see what happens.

Ingo has applied an updated version to x86/urgent:

https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?h=x86/urgent&id=a89652769470d12cd484ee3d3f7bde0742be8d96

-- 
 Kirill A. Shutemov
--
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/