lkml.org 
[lkml]   [2012]   [Feb]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v8 3/8] seccomp: add system call filtering using BPF
On 02/16/2012 01:51 PM, Will Drewry wrote:
>>
>> Put the bloody bit in there and let the pattern program make that decision.
>
> Easy enough to add a bit for the mode: 32-bit or 64-bit. It seemed
> like a waste of cycles for every 32-bit program or every 64-bit
> program to check to see that its calling convention hadn't changed,
> but it does take away a valid decision the pattern program should be
> making.
>
> I'll add a flag for 32bit/64bit while cleaning up seccomp_data. I
> think that will properly encapsulate the is_compat_task() behavior in
> a way that is stable for compat and non-compat tasks to use. If
> there's a more obvious way, I'm all ears.
>

is_compat_task() is not going to be the right thing for x86 going
forward, as we're introducing the x32 ABI (which uses the normal x86-64
entry point, but with different eax numbers, and bit 30 set.)

The actual state is the TS_COMPAT flag in the thread_info structure,
which currently matches is_compat_task(), but perhaps we should add a
new helper function syscall_namespace() or something like that...

Either that or we can just use another bit in the syscall number field...

-hpa

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



\
 
 \ /
  Last update: 2012-02-16 23:09    [W:0.088 / U:0.300 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site