From: Willy Tarreau <w@1wt.eu>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
Andy Lutomirski <luto@kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@kernel.org>,
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: Tue, 9 Jan 2018 15:54:22 +0100 [thread overview]
Message-ID: <20180109145422.GD12976@1wt.eu> (raw)
In-Reply-To: <20180109145157.5ltqbz4o5sqkcggb@pd.tnic>
On Tue, Jan 09, 2018 at 03:51:57PM +0100, Borislav Petkov wrote:
> On Tue, Jan 09, 2018 at 03:36:53PM +0100, Willy Tarreau wrote:
> > I see and am not particularly against this, but what use case do you
> > have in mind precisely ? I doubt it's just saving a few tens of bytes,
> > so probably you're more concerned about the potential risks this opens ?
> > But given we only allow this for CAP_SYS_RAWIO and these ones already
> > have access to /dev/mem and many other things, don't you think there
> > are much easier ways to dump kernel memory in this case than trying to
> > inject some meltdown code into the victim process ? Or maybe you have
> > other cases in mind that I'm not seeing.
>
> I'd like this to be config-controllable so that distros can make the
> decision whether/if they want to support the whole per-mm thing.
OK.
> Also, if CAP_SYS_RAWIO is going to protect, please make the
> ARCH_GET_NOPTI variant check it too.
Interestingly I removed the check consecutive to the discussions. But
I think I'll simply remove the whole ARCH_GET_NOPTI as it has no real
value beyond initial development.
Willy
next prev parent reply other threads:[~2018-01-09 14:54 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 [this message]
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
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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