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Date: Tue, 6 Sep 2016 12:41:14 -0700
From: Andi Kleen <andi@firstfloor.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>, Jiri Olsa <jolsa@redhat.com>,
        Andi Kleen <andi@firstfloor.org>, Jiri Olsa <jolsa@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH] fs/proc/kcore.c: Omit kernel text area for hardened
 usercopy feature
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On Tue, Sep 06, 2016 at 11:34:28AM -0700, Linus Torvalds wrote:
> On Tue, Sep 6, 2016 at 10:56 AM, Kees Cook <keescook@chromium.org> wrote:
> >
> > In the meantime, how about continuing to use a bounce buffer like
> > already done in the vmalloc_or_module_addr() case immediately above?
> 
> Yes please. Let's not make up even more of the user access functions
> with magical properties, for some special-case code in /proc/kcore.

I suspect it's more than just /proc/kcore, there could be also 
legitimate cases to read kernel text from /dev/mem or /dev/kmem

I suppose could add bounce buffers everywhere.

-Andi