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From: Kees Cook <keescook@chromium.org>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Alexander Potapenko" <glider@google.com>,
	"Joe Perches" <joe@perches.com>,
	"open list:ANDROID DRIVERS" <devel@driverdev.osuosl.org>,
	"Jann Horn" <jannh@google.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Arve Hjønnevåg" <arve@android.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Dmitriy Vyukov" <dvyukov@google.com>,
	"Todd Kjos" <tkjos@google.com>
Subject: Re: [PATCH v2 2/3] binder: do not initialize locals passed to copy_from_user()
Date: Wed, 4 Mar 2020 10:13:40 -0800	[thread overview]
Message-ID: <202003040951.7857DFD936@keescook> (raw)
In-Reply-To: <20200303093832.GD24372@kadam>

On Tue, Mar 03, 2020 at 12:38:32PM +0300, Dan Carpenter wrote:
> The real fix is to initialize everything manually, the automated
> initialization is a hardenning feature which many people will disable.

I cannot disagree more with this sentiment. Linus has specifically said he
wants this initialization on by default[1], and the major thing holding
that back from happening is that no one working on GCC has had time to
add this feature there. All the kernels I know of that are built with
Clang (Android, Chrome OS, OpenMandriva) either already have this turned
on or have plans to do so shortly.

> So I don't think the hardenning needs to be perfect, it needs to simple
> and fast.

I think it should be able to be intelligently optimized, so I'm all for
finding ways to mark function arguments as "will be initialized" in some
fashion.

-Kees

[1] "Oh, I love that patch." https://lore.kernel.org/lkml/CA+55aFykZL+cSBJjBBts7ebEFfyGPdMzTmLSxKnT_29=j942dA@mail.gmail.com/

-- 
Kees Cook

  parent reply	other threads:[~2020-03-04 18:13 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-02 13:04 [PATCH v2 1/3] compiler.h: define __no_initialize glider
2020-03-02 13:04 ` [PATCH v2 2/3] binder: do not initialize locals passed to copy_from_user() glider
2020-03-02 13:09   ` Joe Perches
2020-03-02 13:25     ` Alexander Potapenko
2020-03-02 13:52       ` Dan Carpenter
2020-03-02 13:58       ` Joe Perches
2020-03-02 18:17         ` Alexander Potapenko
2020-03-02 18:31           ` Jann Horn
2020-03-05  9:03             ` Rasmus Villemoes
2020-03-05 12:45               ` Jann Horn
2020-03-06  2:29               ` Al Viro
2020-03-02 18:50           ` Joe Perches
2020-03-03  9:14             ` Alexander Potapenko
2020-03-03  9:38               ` Dan Carpenter
2020-03-03 13:56                 ` Joe Perches
2020-03-03 14:15                   ` Dan Carpenter
2020-03-04 18:13                 ` Kees Cook [this message]
2020-03-05  8:07                   ` Dan Carpenter
2020-03-05  8:26                     ` Kees Cook
2020-03-05  8:33                       ` Alexander Potapenko
2020-03-02 17:38   ` Greg KH
2020-03-02 18:28     ` Alexander Potapenko
2020-03-02 13:04 ` [PATCH v2 3/3] sched/wait: avoid double initialization in ___wait_event() glider
2020-03-02 16:56   ` Todd Kjos
2020-03-02 18:03     ` Alexander Potapenko
2020-03-02 18:39       ` Greg Kroah-Hartman

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