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From: Andrew Morton <akpm@linux-foundation.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>,
	Andi Kleen <ak@linux.intel.com>,
	Markus T Metzger <markus.t.metzger@intel.com>,
	Ravi Shankar <ravi.v.shankar@intel.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 01/13] taint: Introduce a new taint flag (insecure)
Date: Tue, 5 Feb 2019 13:21:46 -0800	[thread overview]
Message-ID: <20190205132146.2e61b3df9e7be49e22b7d903@linux-foundation.org> (raw)
In-Reply-To: <CALCETrXi=PEOXCQYkCO9BLL+oaoJonRohWoxvUqxZdiWURc3=Q@mail.gmail.com>

On Fri, 1 Feb 2019 18:42:29 -0800 Andy Lutomirski <luto@kernel.org> wrote:

> On Fri, Feb 1, 2019 at 12:54 PM Chang S. Bae <chang.seok.bae@intel.com> wrote:
> >
> > For testing (or root-only) purposes, the new flag will serve to tag the
> > kernel taint accurately.
> >
> > When adding a new feature support, patches need to be incrementally
> > applied and tested with temporal parameters. Currently, there is no flag
> > for this usage.
> 
> I think this should be reviewed by someone like akpm.  akpm, for
> background, this is part of an x86 patch series.  If only part of the
> series is applied, the kernel will be blatantly insecure (but still
> functional and useful for testing and bisection), and this taint flag
> will be set if this kernel is booted.  With the whole series applied,
> there are no users of the taint flag in the kernel.
> 
> Do you think this is a good idea?

What does "temporal parameters" mean?  A complete description of this
testing process would help.

I sounds a bit strange.  You mean it assumes that people will partially
apply the series to test its functionality?  That would be inconvenient.

- Can the new and now-unused taint flag be removed again at
  end-of-series?

- It would be a lot more convenient if we had some means of testing
  after the whole series is applied, on a permanent basis - some
  debugfs flag, perhaps?

  reply	other threads:[~2019-02-05 21:21 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-01 20:53 [PATCH v5 00/13] x86: Enable FSGSBASE instructions Chang S. Bae
2019-02-01 20:53 ` [PATCH v5 01/13] taint: Introduce a new taint flag (insecure) Chang S. Bae
2019-02-02  2:42   ` Andy Lutomirski
2019-02-05 21:21     ` Andrew Morton [this message]
2019-02-05 22:46       ` Randy Dunlap
2019-02-05 23:07         ` hpa
2019-02-01 20:53 ` [PATCH v5 02/13] x86/fsgsbase/64: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE Chang S. Bae
2019-02-01 20:53 ` [PATCH v5 03/13] kbuild: Raise the minimum required binutils version to 2.21 Chang S. Bae
2019-02-02  2:45   ` Andy Lutomirski
2019-02-05  0:08     ` Andrew Morton
2019-02-01 20:53 ` [PATCH v5 04/13] x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions Chang S. Bae
2019-02-02  2:52   ` Andy Lutomirski
2019-02-01 20:53 ` [PATCH v5 04/13] x86/fsgsbase/64: Add intrinsics/macros " Chang S. Bae
2019-02-01 20:53 ` [PATCH v5 05/13] x86/fsgsbase/64: Enable FSGSBASE instructions in the helper functions Chang S. Bae
2019-02-02  2:57   ` Andy Lutomirski
2019-02-01 20:53 ` [PATCH v5 06/13] x86/fsgsbase/64: Preserve FS/GS state in __switch_to() if FSGSBASE is on Chang S. Bae
2019-02-01 20:53 ` [PATCH v5 07/13] x86/fsgsbase/64: When copying a thread, use the FSGSBASE instructions if available Chang S. Bae
2019-02-02 17:28   ` Andy Lutomirski
2019-02-01 20:53 ` [PATCH v5 08/13] x86/fsgsbase/64: Introduce the FIND_PERCPU_BASE macro Chang S. Bae
2019-02-02 17:17   ` Andy Lutomirski
2019-02-13 18:46     ` Bae, Chang Seok
2019-02-01 20:53 ` [PATCH v5 09/13] x86/fsgsbase/64: Use the per-CPU base as GSBASE at the paranoid_entry Chang S. Bae
2019-02-01 20:53 ` [PATCH v5 10/13] selftests/x86/fsgsbase: Test WRGSBASE Chang S. Bae
2019-02-01 20:53 ` [PATCH v5 11/13] x86/fsgsbase/64: Enable FSGSBASE by default and add a chicken bit Chang S. Bae
2019-02-01 20:53 ` [PATCH v5 12/13] x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 Chang S. Bae
2019-02-01 20:53 ` [PATCH v5 13/13] x86/fsgsbase/64: Add documentation for FSGSBASE Chang S. Bae
2019-02-01 23:02 ` [PATCH v5 00/13] x86: Enable FSGSBASE instructions Andi Kleen
2019-02-02  2:43 ` Andy Lutomirski
2019-02-05  6:26   ` hpa

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