Messages in this thread Patch in this message | | | Date | Thu, 20 Jan 2011 21:32:00 +0100 | From | matthieu castet <> | Subject | Re: [PATCH 3/3 V13] RO/NX protection for loadable kernel |
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Xiaotian Feng a écrit : > On Thu, Dec 23, 2010 at 5:35 AM, <Valdis.Kletnieks@vt.edu> wrote: >> On Wed, 22 Dec 2010 13:40:19 +0100, Ingo Molnar said: >>> * mat <castet.matthieu@free.fr> wrote: >>> >>>> Le Wed, 8 Dec 2010 14:19:51 -0800, >>>> Kees Cook <kees.cook@canonical.com> a écrit : >>>> >>>>> On Fri, Nov 26, 2010 at 06:23:55PM +0100, mat wrote: >>>>>> could you try the attached patch ? >>>>>> >>>>>> on module load, we sort the __jump_table section. So we should make >>>>>> it writable. >>>>>> >>>>>> >>>>>> Matthieu >>>>>> diff --git a/arch/x86/include/asm/jump_label.h >>>>>> b/arch/x86/include/asm/jump_label.h index f52d42e..574dbc2 100644 >>>>>> --- a/arch/x86/include/asm/jump_label.h >>>>>> +++ b/arch/x86/include/asm/jump_label.h >>>>>> @@ -14,7 +14,7 @@ >>>>>> do >>>>>> { \ asm >>>>>> goto("1:" \ >>>>>> JUMP_LABEL_INITIAL_NOP \ >>>>>> - ".pushsection __jump_table, \"a\" \n\t"\ >>>>>> + ".pushsection __jump_table, \"aw\" \n\t"\ >>>>>> _ASM_PTR "1b, %l[" #label "], %c0 \n\t" \ >>>>>> ".popsection \n\t" \ >>>>>> : : "i" (key) : : label); >>>>>> \ >>>>> Acked-by: Kees Cook <kees.cook@canonical.com> >>>>> >>>>> Can this please get committed to tip? >>>> I think it is not need anymore with Steven Rostedt patch [1] >>>> >>>> Matthieu >>>> >>>> [1] >>>>>> Here we set the text read only before we call the notifiers. The >>>>>> function tracer changes the calls to mcount into nops via a notifier >>>>>> call so this must be done after the module notifiers. >>> What's the status of this bug? >>> >>> If we still need the patch then please submit it standalone with a proper subject >>> line, with acks/signoffs added, etc. >> Steve Rostedt's patch that moves the setting of the page permissions seems to >> make this patch no longer necessary. I tripped over this same issue, but the >> version in the latest -mmotm does not need it, as it includes Steve's fix. >> > > I'm facing a boot failure (panic'ed on remove_jump_label_module_init) > on 2.6.37 (latest commit 3c0cb7c), which is 100% reproducible. > With this patch applied, I can boot my machine successfully, so I do > think this patch is needed. > Could you confirm that this patch fix the problem ?
Matthieu From 0eeba453aaba0ebff86f0a7ad9bfb8afbde0c0dc Mon Sep 17 00:00:00 2001 From: Matthieu CASTET <castet.matthieu@free.fr> Date: Thu, 20 Jan 2011 21:25:03 +0100 Subject: [PATCH] Fix jump table in module init section
If we use jump table in module init, there are marked as removed in __jump_table section after init is done.
But we already applied ro permissions on the module, so we can't modify a read only section (crash in remove_jump_label_module_init).
Make the __jump_table section rw.
Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr> --- arch/x86/include/asm/jump_label.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h index f52d42e..574dbc2 100644 --- a/arch/x86/include/asm/jump_label.h +++ b/arch/x86/include/asm/jump_label.h @@ -14,7 +14,7 @@ do { \ asm goto("1:" \ JUMP_LABEL_INITIAL_NOP \ - ".pushsection __jump_table, \"a\" \n\t"\ + ".pushsection __jump_table, \"aw\" \n\t"\ _ASM_PTR "1b, %l[" #label "], %c0 \n\t" \ ".popsection \n\t" \ : : "i" (key) : : label); \ -- 1.7.2.3
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