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From: Peter Zijlstra <peterz@infradead.org>
To: David Windsor <dave@progbits.org>
Cc: kernel-hardening@lists.openwall.com,
	Will Deacon <will.deacon@arm.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	Elena Reshetova <elena.reshetova@intel.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	"H. Peter Anvin" <h.peter.anvin@intel.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [kernel-hardening] Re: [RFC v4 PATCH 00/13] HARDENED_ATOMIC
Date: Thu, 10 Nov 2016 22:39:52 +0100	[thread overview]
Message-ID: <20161110213952.GB3117@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAEXv5_i3Ju5JNs6g-jA-WkMR38g43Aj5we0+GXeHcuUAM3nziQ@mail.gmail.com>

On Thu, Nov 10, 2016 at 04:23:08PM -0500, David Windsor wrote:
> Discussions have been occurring since KSPP has begun: do we need a

Note that I was not included in any of that. If you hide in a corner on
the intartubes don't be surprised people have no clue what you're on
about.

> specialized type for reference counters?  Oh, wait, we do: kref.
> Wait!  kref is implemented with atomic_t.
> 
> So, what?  We obviously need an atomicity for a reference counter
> type.  So, do we simply implement the HARDENED_ATOMIC protected
> version of atomic_t "inside" of kref and leave atomic_t alone?

But you could provide a small subset of the atomic_t API for that, under
a different type.

That way you don't get utter shite like atomic_cmpxchg_wrap() for
instance.

>From what I can see only all the add/sub variants have overflow checks,
but all the operations get _wrap() prefixes, even where it doesn't make
any bloody sense. _wrap() on bitops?, _wrap() on cmpxchg(). You must be
bloody joking right?

  parent reply	other threads:[~2016-11-10 21:40 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1478809488-18303-1-git-send-email-elena.reshetova@intel.com>
2016-11-10 20:37 ` Peter Zijlstra
2016-11-10 20:48   ` Will Deacon
2016-11-10 21:01     ` Kees Cook
2016-11-10 21:23       ` [kernel-hardening] " David Windsor
2016-11-10 21:27         ` Kees Cook
2016-11-10 21:39           ` David Windsor
2016-11-10 21:39         ` Peter Zijlstra [this message]
2016-11-10 21:13     ` Peter Zijlstra
2016-11-10 21:23       ` Kees Cook
2016-11-11  4:25         ` [kernel-hardening] " Rik van Riel
2016-11-10 22:27       ` Greg KH
2016-11-10 23:15         ` Kees Cook
2016-11-10 23:38           ` Greg KH
2016-11-10 23:57           ` Peter Zijlstra
2016-11-11  0:29             ` Colin Vidal
2016-11-11 12:41               ` Mark Rutland
2016-11-11 12:47                 ` Peter Zijlstra
2016-11-11 13:00                   ` Peter Zijlstra
2016-11-11 14:39                     ` Thomas Gleixner
2016-11-11 14:48                       ` Peter Zijlstra
2016-11-11 23:07                     ` Peter Zijlstra
2016-11-13 11:03             ` Greg KH
2016-11-10 20:56   ` Kees Cook
2016-11-11  3:20     ` [kernel-hardening] " David Windsor

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