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From: Greg KH <gregkh@linuxfoundation.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arch@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	kernel-hardening@lists.openwall.com,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Netdev <netdev@vger.kernel.org>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"David S. Miller" <davem@davemloft.net>,
	Elena Reshetova <elena.reshetova@intel.com>,
	Alan Cox <alan@linux.intel.com>
Subject: Re: [PATCH v2 10/19] ipv4: prevent bounds-check bypass via speculative execution
Date: Sat, 13 Jan 2018 09:56:35 +0100	[thread overview]
Message-ID: <20180113085635.GA11640@kroah.com> (raw)
In-Reply-To: <CAPcyv4js=KTb+eJjoc4_hjiJsiHr4EApJfxTjFfRBYx_CtuBKA@mail.gmail.com>

On Fri, Jan 12, 2018 at 10:47:44AM -0800, Dan Williams wrote:
> On Thu, Jan 11, 2018 at 11:59 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> >> Cc: "David S. Miller" <davem@davemloft.net>
> >> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
> >> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
> >> Cc: netdev@vger.kernel.org
> >> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
> >> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> >> ---
> >>  net/ipv4/raw.c |   10 ++++++----
> >>  1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > Ugh, what is this, the 4th time I've said "I don't think this is an
> > issue, so why are you changing this code." to this patch.  To be
> > followed by a "oh yeah, you are right, I'll drop it", only to see it
> > show back up in the next time this patch series is sent out?
> >
> > Same for the other patches in this series that I have reviewed 4, maybe
> > 5, times already.  The "v2" is not very true here...
> 
> The theme of the review feedback on v1 was 'don't put ifence in any
> net/ code', and that was addressed.
> 
> I honestly thought the new definition of array_ptr() changed the
> calculus on this patch. Given the same pattern appears in the ipv6
> case, and I have yet to hear that we should drop the ipv6 patch, make
> the code symmetric just for readability purposes. Otherwise we need a
> comment saying why this is safe for ipv4, but maybe not safe for ipv6,
> I think 'array_ptr' is effectively that comment. I.e. 'array_ptr()' is
> designed to be low impact for instrumenting false positives. If that
> new argument does not hold water I will definitely drop this patch.

I also argued, again in an older review of this same patch series, that
the ipv6 patch should be dropped as well for this same exact reason.

I didn't think you wanted to hear me rant about the same thing on both
patches :)

greg k-h

  parent reply	other threads:[~2018-01-13  8:56 UTC|newest]

Thread overview: 103+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-12  0:46 [PATCH v2 00/19] prevent bounds-check bypass via speculative execution Dan Williams
2018-01-12  0:46 ` Dan Williams
2018-01-12  0:46 ` [PATCH v2 01/19] Documentation: document array_ptr Dan Williams
2018-01-12  0:46   ` Dan Williams
2018-01-12 10:38   ` Geert Uytterhoeven
2018-01-12 10:38     ` Geert Uytterhoeven
2018-01-16 21:01   ` Kees Cook
2018-01-16 21:01     ` Kees Cook
2018-01-12  0:46 ` [PATCH v2 02/19] arm64: implement ifence_array_ptr() Dan Williams
2018-01-12  0:46   ` Dan Williams
2018-01-12  0:46 ` [PATCH v2 03/19] arm: " Dan Williams
2018-01-12  0:46 ` [PATCH v2 04/19] x86: implement ifence() Dan Williams
2018-01-12  0:46   ` Dan Williams
2018-01-12  2:27   ` Eric W. Biederman
2018-01-12  2:27     ` Eric W. Biederman
2018-01-12  3:39     ` Dan Williams
2018-01-12  0:46 ` [PATCH v2 05/19] x86: implement ifence_array_ptr() and array_ptr_mask() Dan Williams
2018-01-12  0:46   ` Dan Williams
2018-01-12  0:46 ` [PATCH v2 06/19] asm-generic/barrier: mask speculative execution flows Dan Williams
2018-01-12  2:42   ` Eric W. Biederman
2018-01-12  9:12   ` Peter Zijlstra
2018-01-13  0:41     ` Dan Williams
2018-01-15  8:46       ` Peter Zijlstra
2018-01-12  0:47 ` [PATCH v2 07/19] x86: introduce __uaccess_begin_nospec and ASM_IFENCE Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-12 17:51   ` Josh Poimboeuf
2018-01-12 18:21     ` Dan Williams
2018-01-12 18:58       ` Josh Poimboeuf
2018-01-12 18:58         ` Josh Poimboeuf
2018-01-12 19:26         ` Dan Williams
2018-01-12 19:26           ` Dan Williams
2018-01-12 20:01           ` Linus Torvalds
2018-01-12 20:01             ` Linus Torvalds
2018-01-12 20:41             ` Josh Poimboeuf
2018-01-12 20:41               ` Josh Poimboeuf
2018-01-12  0:47 ` [PATCH v2 08/19] x86: use __uaccess_begin_nospec and ASM_IFENCE in get_user paths Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-12  1:11   ` Linus Torvalds
2018-01-12  1:14     ` Dan Williams
2018-01-12  1:14       ` Dan Williams
2018-01-12  0:47 ` [PATCH v2 09/19] ipv6: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-12  0:47 ` [PATCH v2 10/19] ipv4: " Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-12  7:59   ` Greg KH
2018-01-12  7:59     ` Greg KH
2018-01-12 18:47     ` Dan Williams
2018-01-12 18:47       ` Dan Williams
2018-01-13  8:56       ` Greg KH [this message]
2018-01-13  8:56         ` Greg KH
2018-01-12  0:47 ` [PATCH v2 11/19] vfs, fdtable: " Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-12  0:47 ` [PATCH v2 12/19] userns: " Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-12  0:47 ` [PATCH v2 13/19] udf: " Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-15 10:32   ` Jan Kara
2018-01-15 17:49     ` Dan Williams
2018-01-12  0:47 ` [PATCH v2 14/19] [media] uvcvideo: " Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-08-06 21:40   ` Laurent Pinchart
2018-08-06 21:40     ` Laurent Pinchart
2018-01-12  0:47 ` [PATCH v2 15/19] carl9170: " Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-12 14:42   ` Christian Lamparter
2018-01-12 14:42     ` Christian Lamparter
2018-01-12 18:39     ` Dan Williams
2018-01-12 20:01       ` Christian Lamparter
2018-01-12 20:01         ` Christian Lamparter
2018-01-12 23:05         ` Dan Williams
2018-01-12 23:05           ` Dan Williams
2018-01-12  0:47 ` [PATCH v2 16/19] p54: " Dan Williams
2018-01-12  0:47 ` [PATCH v2 17/19] qla2xxx: " Dan Williams
2018-01-12  0:47   ` Dan Williams
2018-01-12  1:19   ` James Bottomley
2018-01-12  1:19     ` James Bottomley
2018-01-12  5:38     ` Dan Williams
2018-01-12  5:38       ` Dan Williams
2018-01-12  6:05       ` James Bottomley
2018-01-12  0:48 ` [PATCH v2 18/19] cw1200: " Dan Williams
2018-01-12  0:48   ` Dan Williams
2018-01-12  0:48 ` [PATCH v2 19/19] net: mpls: " Dan Williams
2018-01-12  0:48   ` Dan Williams
2018-01-12  1:19 ` [PATCH v2 00/19] " Linus Torvalds
2018-01-12  1:19   ` Linus Torvalds
2018-01-12  1:41   ` Dan Williams
2018-01-12  1:41     ` Dan Williams
2018-01-18 13:18     ` Will Deacon
2018-01-18 13:18       ` Will Deacon
2018-01-18 16:58       ` Dan Williams
2018-01-18 16:58         ` Dan Williams
2018-01-18 17:05         ` Will Deacon
2018-01-18 17:05           ` Will Deacon
2018-01-18 21:41           ` Laurent Pinchart
2018-01-18 21:41             ` Laurent Pinchart
2018-01-13  0:15   ` Tony Luck
2018-01-13  0:15     ` Tony Luck
2018-01-13 18:51     ` Linus Torvalds
2018-01-13 18:51       ` Linus Torvalds
2018-01-16 19:21       ` Tony Luck
2018-01-16 19:21         ` Tony Luck
2018-01-12 10:02 ` Russell King - ARM Linux
2018-01-12 10:02   ` Russell King - ARM Linux

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