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From: Jiri Kosina <jikos@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Paul Turner <pjt@google.com>,
	Greg Kroah-Hartman <gregkh@linux-foundation.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Ingo Molnar <mingo@kernel.org>, Rik van Riel <riel@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andi Kleen <ak@linux.intel.com>, Kees Cook <keescook@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/pti] x86/retpoline: Fill return stack buffer on vmexit
Date: Thu, 25 Jan 2018 19:41:03 +0100 (CET)	[thread overview]
Message-ID: <nycvar.YFH.7.76.1801251937380.11852@cbobk.fhfr.pm> (raw)
In-Reply-To: <CALCETrWHJZXqDC-PUStHAJrNVMO_QEC0PG0PKAEHD+8TB-eqqQ@mail.gmail.com>

On Thu, 25 Jan 2018, Andy Lutomirski wrote:

> Distros that use retpolines need their driver vendors to recompile no 
> matter what.  

Absolutely. Tainting a kernel, issuing a warning, or even voluntarily 
deciding to not load modules loaded without retpolines, that all sounds 
like reasonable aproaches.

Artificially introducing kernel ABI breakage which is not there (as 
retpolines are fully compatible when it comes to ABI between modules and 
kernel ... the fact that it potentially brings non-retpolined indirect 
jump into the kernel is a security concent, but not ABI issue) sounds like 
a bad idea.

Those two things (ABI and security concerns) are independent.

> Distros that use IBRS and refuse to use retpolines should get put on a 
> list of "didn't actually adequately mitigate spectre".

Oh absolutely, especially on archs where there is no IBRS. But how is this 
relevant to ABI?

Thanks,

-- 
Jiri Kosina
SUSE Labs

  parent reply	other threads:[~2018-01-25 18:41 UTC|newest]

Thread overview: 85+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-11 21:46 [PATCH v8 00/12] Retpoline: Avoid speculative indirect calls in kernel David Woodhouse
2018-01-11 21:46 ` [PATCH v8 01/12] objtool: Detect jumps to retpoline thunks David Woodhouse
2018-01-11 23:22   ` [tip:x86/pti] " tip-bot for Josh Poimboeuf
2018-01-11 21:46 ` [PATCH v8 02/12] objtool: Allow alternatives to be ignored David Woodhouse
2018-01-11 23:22   ` [tip:x86/pti] " tip-bot for Josh Poimboeuf
2018-01-18 19:09   ` [v8,02/12] " Guenter Roeck
2018-01-18 19:33     ` Josh Poimboeuf
2018-01-18 19:41       ` Guenter Roeck
2018-01-22 19:34         ` David Woodhouse
2018-01-22 20:25           ` Guenter Roeck
2018-01-22 20:27             ` David Woodhouse
2018-01-28 21:06             ` Josh Poimboeuf
2018-01-29  1:26               ` Guenter Roeck
2018-01-29 17:15               ` Guenter Roeck
2018-01-29 17:30                 ` Josh Poimboeuf
2018-01-22 19:27       ` Guenter Roeck
2018-01-11 21:46 ` [PATCH v8 03/12] x86/retpoline: Add initial retpoline support David Woodhouse
2018-01-11 23:23   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 23:58   ` [PATCH v8 03/12] " Tom Lendacky
2018-01-12 10:28     ` David Woodhouse
2018-01-12 14:02       ` Tom Lendacky
2018-01-14 15:02   ` Borislav Petkov
2018-01-14 15:53     ` Josh Poimboeuf
2018-01-14 15:59       ` Borislav Petkov
2018-01-11 21:46 ` [PATCH v8 04/12] x86/spectre: Add boot time option to select Spectre v2 mitigation David Woodhouse
2018-01-11 23:23   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-23 22:40   ` [PATCH v8 04/12] " Borislav Petkov
2018-01-23 22:53     ` David Woodhouse
2018-01-23 23:05       ` Andi Kleen
2018-01-23 22:55     ` Jiri Kosina
2018-01-23 23:05       ` Borislav Petkov
2018-01-24  0:32         ` Kees Cook
2018-01-24  9:58           ` Borislav Petkov
2018-01-23 23:06       ` Jiri Kosina
2018-01-23 23:21       ` Andi Kleen
2018-01-23 23:24         ` Jiri Kosina
2018-01-23 23:45           ` Andi Kleen
2018-01-23 23:49             ` Jiri Kosina
2018-01-24  4:26               ` Greg Kroah-Hartman
2018-01-24  9:56                 ` Jiri Kosina
2018-01-24 13:58                   ` Greg Kroah-Hartman
2018-01-24 14:03                     ` Jiri Kosina
2018-01-24 14:22                       ` Greg Kroah-Hartman
2018-01-11 21:46 ` [PATCH v8 05/12] x86/retpoline/crypto: Convert crypto assembler indirect jumps David Woodhouse
2018-01-11 23:24   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 06/12] x86/retpoline/entry: Convert entry " David Woodhouse
2018-01-11 23:24   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 07/12] x86/retpoline/ftrace: Convert ftrace " David Woodhouse
2018-01-11 23:25   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 08/12] x86/retpoline/hyperv: Convert " David Woodhouse
2018-01-11 23:25   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 09/12] x86/retpoline/xen: Convert Xen hypercall " David Woodhouse
2018-01-11 23:25   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 10/12] x86/retpoline/checksum32: Convert assembler " David Woodhouse
2018-01-11 23:26   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 21:46 ` [PATCH v8 11/12] x86/retpoline/irq32: " David Woodhouse
2018-01-11 23:26   ` [tip:x86/pti] " tip-bot for Andi Kleen
2018-01-11 21:46 ` [PATCH v8 12/12] x86/retpoline: Fill return stack buffer on vmexit David Woodhouse
2018-01-11 23:27   ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-11 23:51   ` [PATCH v8 12/12] " Andi Kleen
2018-01-12 11:11     ` [PATCH v8.1 " David Woodhouse
2018-01-12 11:15       ` Thomas Gleixner
2018-01-12 11:21         ` Woodhouse, David
2018-01-12 11:37       ` [tip:x86/pti] " tip-bot for David Woodhouse
2018-01-14 14:50         ` Borislav Petkov
2018-01-14 15:28           ` Thomas Gleixner
2018-01-14 15:35         ` Borislav Petkov
2018-01-25 12:07         ` Borislav Petkov
2018-01-25 12:20           ` David Woodhouse
2018-01-25 12:45             ` Borislav Petkov
2018-01-25 15:10               ` Josh Poimboeuf
2018-01-25 15:51                 ` Borislav Petkov
2018-01-25 16:03                   ` David Woodhouse
2018-01-25 16:56                     ` Josh Poimboeuf
2018-01-25 17:00                       ` David Woodhouse
2018-01-25 17:05                         ` Andy Lutomirski
2018-01-25 17:44                           ` Josh Poimboeuf
2018-01-25 18:41                           ` Jiri Kosina [this message]
2018-01-25 17:10                         ` Thomas Gleixner
2018-01-25 17:32                         ` Josh Poimboeuf
2018-01-25 17:53                         ` Borislav Petkov
2018-01-25 18:04                           ` David Woodhouse
2018-01-25 18:32                             ` Josh Poimboeuf
2018-01-25 19:07                             ` Borislav Petkov
2018-01-25 19:10                               ` Borislav Petkov

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