From: Willy Tarreau <w@1wt.eu>
To: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@kernel.org>, Andy Lutomirski <luto@kernel.org>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [RFC PATCH v2 2/6] x86/arch_prctl: add ARCH_GET_NOPTI and ARCH_SET_NOPTI to enable/disable PTI
Date: Wed, 10 Jan 2018 16:43:18 +0100 [thread overview]
Message-ID: <20180110154318.GC14178@1wt.eu> (raw)
In-Reply-To: <20180110144506.mh7kvqnjyk5b4dvx@pd.tnic>
On Wed, Jan 10, 2018 at 03:45:06PM +0100, Borislav Petkov wrote:
> On Wed, Jan 10, 2018 at 08:25:08AM +0100, Ingo Molnar wrote:
> > We could taint the kernel and warn prominently in the syslog when PTI is disabled
> > globally on the boot line though, if running on affected CPUs.
> >
> > Something like:
> >
> > "x86/intel: Page Table Isolation (PTI) is disabled globally. This allows unprivileged, untrusted code to exploit the Meltdown CPU bug to read kernel data."
> >
>
> I think we should warn in the per-mm disabling case too. Not the same
> text but a similar blurb about the trusted process becoming a high-value
> target.
Well, we don't warn when /dev/mem is opened read-only, even not when
it's opened R/W, and it exposes the contents much better. Tainting is
first a support help so that developers don't waste time debugging
something that might have been altered. In this case nothing got
altered. At best(worst?) things might have been disclosed. That said
I'm all for at least tainting when running with pti=off at least to
educate users.
Willy
next prev parent reply other threads:[~2018-01-10 15:44 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-09 12:56 [RFC PATCH v2 0/6] Per process PTI activation Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 1/6] x86/mm: add a pti_disable entry in mm_context_t Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 2/6] x86/arch_prctl: add ARCH_GET_NOPTI and ARCH_SET_NOPTI to enable/disable PTI Willy Tarreau
2018-01-09 14:17 ` Borislav Petkov
2018-01-09 14:36 ` Willy Tarreau
2018-01-09 14:51 ` Borislav Petkov
2018-01-09 14:54 ` Willy Tarreau
2018-01-09 21:26 ` Andy Lutomirski
2018-01-09 21:29 ` Borislav Petkov
2018-01-09 21:32 ` Willy Tarreau
2018-01-09 21:46 ` Borislav Petkov
2018-01-09 22:06 ` Willy Tarreau
2018-01-09 22:20 ` Borislav Petkov
2018-01-09 22:29 ` Dave Hansen
2018-01-09 22:40 ` Willy Tarreau
2018-01-10 14:42 ` Borislav Petkov
2018-01-10 15:39 ` Willy Tarreau
2018-01-10 16:09 ` Borislav Petkov
2018-01-10 16:19 ` Willy Tarreau
2018-01-10 17:28 ` Borislav Petkov
2018-01-10 7:31 ` Ingo Molnar
2018-01-10 7:37 ` Willy Tarreau
2018-01-10 7:59 ` Ingo Molnar
2018-01-09 23:53 ` Andy Lutomirski
2018-01-10 4:25 ` Willy Tarreau
2018-01-10 7:25 ` Ingo Molnar
2018-01-10 14:45 ` Borislav Petkov
2018-01-10 15:43 ` Willy Tarreau [this message]
2018-01-10 15:45 ` Ingo Molnar
2018-01-09 21:34 ` Kees Cook
2018-01-09 21:41 ` Willy Tarreau
2018-01-09 21:50 ` Kees Cook
2018-01-09 22:03 ` Willy Tarreau
2018-01-10 7:13 ` Ingo Molnar
2018-01-12 15:03 ` David Laight
2018-01-12 15:06 ` Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 3/6] x86/pti: add a per-cpu variable pti_disable Willy Tarreau
2018-01-10 7:19 ` Ingo Molnar
2018-01-10 7:29 ` Willy Tarreau
2018-01-10 8:01 ` Ingo Molnar
2018-01-10 8:50 ` Willy Tarreau
2018-01-10 8:59 ` Ingo Molnar
2018-01-10 9:00 ` Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 4/6] x86/pti: don't mark the user PGD with _PAGE_NX Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 5/6] x86/entry/pti: avoid setting CR3 when it's already correct Willy Tarreau
2018-01-10 7:16 ` Ingo Molnar
2018-01-10 7:18 ` Willy Tarreau
2018-01-10 20:29 ` Dave Hansen
2018-01-11 6:46 ` Willy Tarreau
2018-01-09 12:56 ` [RFC PATCH v2 6/6] x86/entry/pti: don't switch PGD on when pti_disable is set Willy Tarreau
2018-01-10 7:15 ` Ingo Molnar
2018-01-10 7:23 ` Willy Tarreau
2018-01-10 8:22 ` Peter Zijlstra
2018-01-10 9:11 ` Willy Tarreau
2018-01-10 19:21 ` Andy Lutomirski
2018-01-10 19:39 ` Willy Tarreau
2018-01-10 19:44 ` Andy Lutomirski
2018-01-10 19:50 ` Linus Torvalds
2018-01-10 20:04 ` Andy Lutomirski
2018-01-11 6:42 ` Willy Tarreau
2018-01-11 15:29 ` Dave Hansen
2018-01-11 15:44 ` Willy Tarreau
2018-01-11 15:51 ` Dave Hansen
2018-01-11 17:02 ` Andy Lutomirski
2018-01-11 18:21 ` Alexei Starovoitov
2018-01-11 18:30 ` Dave Hansen
2018-01-11 18:32 ` Josh Poimboeuf
2018-01-11 18:36 ` Linus Torvalds
2018-01-11 18:38 ` Dave Hansen
2018-01-11 18:51 ` Linus Torvalds
2018-01-11 18:57 ` Dave Hansen
2018-01-11 19:05 ` Josh Poimboeuf
2018-01-11 19:07 ` Borislav Petkov
2018-01-11 19:17 ` Dave Hansen
2018-01-11 19:19 ` Olivier Galibert
2018-01-11 19:26 ` Josh Poimboeuf
2018-01-11 19:34 ` Alan Cox
2018-01-11 21:23 ` Willy Tarreau
2018-01-11 21:28 ` Linus Torvalds
2018-01-11 22:06 ` Willy Tarreau
2018-01-12 16:37 ` David Laight
2018-01-11 19:12 ` Linus Torvalds
2018-01-11 19:38 ` Alexei Starovoitov
2018-01-11 19:11 ` Willy Tarreau
2018-01-11 20:00 ` Dave Hansen
2018-01-11 17:09 ` Andy Lutomirski
2018-01-11 17:40 ` Willy Tarreau
2018-01-11 17:53 ` Andy Lutomirski
2018-01-11 18:05 ` Willy Tarreau
2018-01-11 18:15 ` Dave Hansen
2018-01-11 18:31 ` Linus Torvalds
2018-01-11 18:25 ` Linus Torvalds
2018-01-11 18:26 ` Linus Torvalds
2018-01-11 19:33 ` Andy Lutomirski
2018-01-12 20:22 ` Ingo Molnar
2018-01-12 21:18 ` Andy Lutomirski
2018-01-12 21:54 ` Willy Tarreau
2018-01-11 21:59 ` Willy Tarreau
2018-01-12 16:27 ` David Laight
2018-01-12 17:55 ` Linus Torvalds
2018-01-12 19:36 ` Willy Tarreau
2018-01-11 18:35 ` Dave Hansen
2018-01-11 21:49 ` Willy Tarreau
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