[lkml]   [2012]   [Feb]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v10 05/11] seccomp: add system call filtering using BPF
On 02/22/2012 11:47 AM, Will Drewry wrote:
>> I highly disagree with every filter having to check the mode: Filters that
>> don't check the arch on e.g. x86 are buggy, so they have to check it, even
>> if it's a 32-bit or 64-bit only system, the filters can't know that and
>> needs to check the arch at every syscall entry. All other info in the data
>> depends on the arch, because of this there isn't much code to share between
>> the two archs, so you can as well have one filter for each arch.
>> Alternative approach: Tell the arch at filter install time and only run the
>> filters with the same arch as the current system call. If no filters are run,
>> deny the systemcall.
> This was roughly how I first implemented compat and non-compat
> support. It causes some implicit behavior across inheritance that is
> not nice though.

This is trivially doable at the BPF level, right? Just make this the
first instruction in the program (either deny or jump to a separate
program branch)... and then there is still "one program" without any
weird inheritance issues?


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

 \ /
  Last update: 2012-02-22 20:57    [W:0.089 / U:0.960 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site