Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 27 Nov 2015 12:09:23 -0800
From: Andy Lutomirski <>
To: Kees Cook <>
Cc: Linus Torvalds <>, Ingo Molnar <>, 
	PaX Team <>, 
	"" <>, 
	Mathias Krause <>, 
	"" <>, Ingo Molnar <>, 
	Thomas Gleixner <>, "H. Peter Anvin" <>, x86-ml <>, 
	Arnd Bergmann <>, Michael Ellerman <>, 
	linux-arch <>, Emese Revfy <>
Subject: Re: [PATCH 0/2] introduce post-init read-only memory

On Fri, Nov 27, 2015 at 12:03 PM, Kees Cook <> wrote:
> On Fri, Nov 27, 2015 at 10:00 AM, Linus Torvalds
> <> wrote:
>> On Thu, Nov 26, 2015 at 11:59 PM, Ingo Molnar <> wrote:
>>> * Andy Lutomirski <> wrote:
>>>> > Can you see any fragility in such a technique?
>>>> After Linus shot down my rdmsr/rwmsr decoding patch, good luck...
>>> I think that case was entirely different, but I've Cc:-ed Linus to shoot my idea
>>> down if it's crap.
>> Yeah, no, I hate it. I'm with the PaX team on this one - I think there
>> are three valid responses, and I think we might want to have a dynamic
>> config option (kernel command line or proc or whatever) to pick
>> between the two:
>>  - just oops and kill the machine, like for any other unhandled kernel
>> page fault. This is probably what you should have on a server
> This is how the v2 series works now.
>>  - print a warning and a backtrace, and just mark the page read-write
>> so that the machine survives, but we get notified and can fix whatever
>> broken code
> This seems very easy to add. Should I basically reverse the effects of
> mark_rodata_ro(), or should I only make the new ro-after-init section
> as RW? (I think the former would be easier.)

I'd suggest verifying that the page in question is
.data..ro_after_init and, if so, marking that one page RW.


Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.