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From: Ingo Molnar <mingo@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>,
	"x86@kernel.org" <x86@kernel.org>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: rwx mapping between ex_table and rodata
Date: Fri, 25 Sep 2015 09:25:33 +0200	[thread overview]
Message-ID: <20150925072533.GA17731@gmail.com> (raw)
In-Reply-To: <CAGXu5j+tTR=x9RTOFvqQP7+W7DFR6N+GUP__uvAicrfTBU1B7w@mail.gmail.com>


* Kees Cook <keescook@chromium.org> wrote:

> On Thu, Sep 24, 2015 at 1:26 PM, Stephen Smalley <sds@tycho.nsa.gov> wrote:
> > Hi,
> >
> > With the attached config and 4.3-rc2 on x86_64, I see the following in /sys/kernel/debug/kernel_page_tables:
> > ...
> > ---[ High Kernel Mapping ]---
> > 0xffffffff80000000-0xffffffff81000000          16M                               pmd
> > 0xffffffff81000000-0xffffffff81600000           6M     ro         PSE     GLB x  pmd
> > 0xffffffff81600000-0xffffffff81775000        1492K     ro                 GLB x  pte
> > 0xffffffff81775000-0xffffffff81800000         556K     RW                 GLB x  pte
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Btw., I think we should run this lookup automatically in late bootup, if 
CONFIG_X86_PTDUMP=y, and print a WARN()ing if there's any RWX permissions in the 
mappings.

That makes sure automated testing picks new bugs up.

Thanks,

	Ingo

  parent reply	other threads:[~2015-09-25  7:25 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-24 20:23 rwx mapping between ex_table and rodata Stephen Smalley
2015-09-24 20:26 ` Fwd: " Stephen Smalley
2015-09-24 22:25   ` Kees Cook
2015-09-25  7:22     ` Ingo Molnar
2015-09-26 16:49       ` Kees Cook
2015-09-28 21:16       ` H. Peter Anvin
2015-09-28 22:05         ` Kees Cook
2015-09-28 22:20           ` H. Peter Anvin
2015-09-25  7:25     ` Ingo Molnar [this message]
2015-09-28 14:11     ` Stephen Smalley
2015-09-28 18:27       ` Kees Cook
2015-10-01  7:09         ` Ingo Molnar
2015-10-01  9:03         ` Thomas Gleixner
2015-10-01  9:12           ` Ingo Molnar
2015-10-01 17:45             ` Kees Cook
2015-10-02  7:19               ` Ingo Molnar

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