lkml.org 
[lkml]   [2015]   [Nov]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [kernel-hardening] [PATCH 0/2] introduce post-init read-only memory
On Fri, Nov 27, 2015 at 12:03 PM, Kees Cook <keescook@chromium.org> wrote:
> On Fri, Nov 27, 2015 at 10:00 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>> On Thu, Nov 26, 2015 at 11:59 PM, Ingo Molnar <mingo@kernel.org> wrote:
>>>
>>> * Andy Lutomirski <luto@amacapital.net> 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.

--Andy


\
 
 \ /
  Last update: 2015-11-27 22:01    [W:0.065 / U:0.552 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site