Re: [kernel-hardening] [PATCH 00/18] Introduce struct layout randomization plugin

From: Laura Abbott <labbott@redhat.com>
To: Kees Cook <keescook@chromium.org>
Cc: "kernel-hardening@lists.openwall.com"
	<kernel-hardening@lists.openwall.com>,
	Michael Leibowitz <michael.leibowitz@intel.com>
Subject: Re: [kernel-hardening] [PATCH 00/18] Introduce struct layout randomization plugin
Date: Tue, 18 Apr 2017 10:15:20 -0700	[thread overview]
Message-ID: <1d5ceac4-b841-7924-bc31-1eef3c9acb43@redhat.com> (raw)
In-Reply-To: <CAGXu5jJyoDiOeih5QMKYTSL+1Lg1yXFEJ38MLYrAnGMy5wRqQA@mail.gmail.com>

On 04/15/2017 11:50 AM, Kees Cook wrote:
> On Thu, Apr 13, 2017 at 4:39 PM, Laura Abbott <labbott@redhat.com> wrote:
>> I gave this a quick spin on my aarch64 Rawhide machine. I needed to
>> change the following to work with gcc7
>>
>> diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
>> index a2d7e933c33f..8dd5134f161a 100644
>> --- a/scripts/gcc-plugins/randomize_layout_plugin.c
>> +++ b/scripts/gcc-plugins/randomize_layout_plugin.c
>> @@ -529,8 +529,8 @@ static void randomize_layout_finish_decl(void *event_data, void *data)
>>
>>         DECL_SIZE(decl) = 0;
>>         DECL_SIZE_UNIT(decl) = 0;
>> -       DECL_ALIGN(decl) = 0;
>> -       DECL_MODE (decl) = VOIDmode;
>> +       SET_DECL_ALIGN(decl, 0);
>> +       SET_DECL_MODE(decl, VOIDmode);
>>         SET_DECL_RTL(decl, 0);
>>         update_decl_size(decl);
>>         layout_decl(decl, 0);
> 
> Very cool, thanks! I'll adjust the common header file to provide these
> macros for gcc pre-7 builds and update the series.
> 
>> It boots but dies with a bunch of kernel faults somewhere after reaching
>> userspace. I'll pick up the debugging next week.
> 
> I've been thinking about splitting up the structure marking patch into
> per-structure markings to make failure bisection easier. I assume
> there's a specific structure that is misbehaving on aarch64 (my first
> guess is always task_struct).
> 
> -Kees
> 

I think this was a build error on my side. I thought I tested with your
-next branch but it was apparently based on -rc2. Several builds with
your -next branch work fine. I'll test again with your v2 and see
what happens.

Thanks,
Laura