lkml.org 
[lkml]   [2012]   [Feb]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v10 05/11] seccomp: add system call filtering using BPF
On 02/22/2012 03:51 PM, Andrew Lutomirski wrote:
> On Wed, Feb 22, 2012 at 3:46 PM, Indan Zupancic <indan@nul.nu> wrote:
>> On Wed, February 22, 2012 20:47, Will Drewry wrote:
>>> On Wed, Feb 22, 2012 at 8:23 AM, Ben Hutchings
>>>> I would have thought the way to make sure the architecture is always
>>>> checked is to pack it together with the syscall number.
>>
>> I missed that suggestion, putting the syscall number and arch in one
>> data field would indeed make it harder to not check the arch.
>
> Is there enough room? On x86-64 at least, rax could conceivably be
> extended to 64 bits some day. Bit 30 is already spoken for by x32.
>

No it couldn't, because we mask off the high 32 bits and thus it could
(theoretically) break user space.

-hpa


--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.



\
 
 \ /
  Last update: 2012-02-23 02:11    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site