Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Wed, 18 Apr 2018 11:33:05 -0700
From: Laura Abbott <labbott@...hat.com>
To: Kees Cook <keescook@...omium.org>, Alexander Popov
 <alex.popov@...ux.com>, Dave Hansen <dave.hansen@...ux.intel.com>,
 Ingo Molnar <mingo@...nel.org>,
 Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Kernel Hardening <kernel-hardening@...ts.openwall.com>,
 PaX Team <pageexec@...email.hu>, Brad Spengler <spender@...ecurity.net>,
 Andy Lutomirski <luto@...nel.org>, Tycho Andersen <tycho@...ho.ws>,
 Mark Rutland <mark.rutland@....com>,
 Ard Biesheuvel <ard.biesheuvel@...aro.org>, Borislav Petkov <bp@...en8.de>,
 Richard Sandiford <richard.sandiford@....com>,
 Thomas Gleixner <tglx@...utronix.de>, "H . Peter Anvin" <hpa@...or.com>,
 Peter Zijlstra <a.p.zijlstra@...llo.nl>, "Dmitry V . Levin"
 <ldv@...linux.org>, Emese Revfy <re.emese@...il.com>,
 Jonathan Corbet <corbet@....net>, Andrey Ryabinin <aryabinin@...tuozzo.com>,
 "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
 Thomas Garnier <thgarnie@...gle.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 Alexei Starovoitov <ast@...nel.org>, Josef Bacik <jbacik@...com>,
 Masami Hiramatsu <mhiramat@...nel.org>, Nicholas Piggin <npiggin@...il.com>,
 Al Viro <viro@...iv.linux.org.uk>, "David S . Miller" <davem@...emloft.net>,
 Ding Tianhong <dingtianhong@...wei.com>, David Woodhouse
 <dwmw@...zon.co.uk>, Josh Poimboeuf <jpoimboe@...hat.com>,
 Steven Rostedt <rostedt@...dmis.org>,
 Dominik Brodowski <linux@...inikbrodowski.net>,
 Juergen Gross <jgross@...e.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Dan Williams <dan.j.williams@...el.com>,
 Mathias Krause <minipli@...glemail.com>,
 Vikas Shivappa <vikas.shivappa@...ux.intel.com>, Kyle Huey
 <me@...ehuey.com>, Dmitry Safonov <dsafonov@...tuozzo.com>,
 Will Deacon <will.deacon@....com>, Arnd Bergmann <arnd@...db.de>,
 Florian Weimer <fweimer@...hat.com>,
 Boris Lukashev <blukashev@...pervictus.com>, X86 ML <x86@...nel.org>,
 LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v11 2/6] x86/entry: Add STACKLEAK erasing the kernel stack
 at the end of syscalls

On 04/16/2018 11:29 AM, Kees Cook wrote:
> On Fri, Apr 6, 2018 at 7:22 AM, Alexander Popov <alex.popov@...ux.com> wrote:
>> This commit introduces the architecture-specific code filling the used
>> part of the kernel stack with a poison value before returning to the
>> userspace. Full STACKLEAK feature also contains the gcc plugin which
>> comes in a separate commit.
> 
> Thanks for sending this again! And thanks for the updated reasoning
> for why this remains a valuable addition:
> 
> https://lkml.kernel.org/r/1523024546-6150-1-git-send-email-alex.popov@linux.com
> 
> I, too, remain convinced this is a good protection to have, even as we
> slowly remove VLAs and try to improve the compiler's initialization of
> stack variables.
> 
> Dave, Ingo, Linus: how does this look? With the assembly rewritten
> into C, the entry changes are very small:
> 
>>   arch/x86/entry/entry_32.S        |  7 ++++++
>>   arch/x86/entry/entry_64.S        |  3 +++
>>   arch/x86/entry/entry_64_compat.S |  5 ++++
>>   arch/x86/entry/erase.c           | 54 ++++++++++++++++++++++++++++++++++++++++
> 
> I'd really like to get people's Ack/Review. :)
> 
> Laura, can this C version work for arm64 as well?
> 
> Thanks,
> 
> -Kees
> 

I did a quick port and it seems to work on a minimal system
(passes LKDTM tests). I'll clean it up and do a few more
tests to send out and see about give this series another
review.

Thanks,
Laura

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.