lkml.org 
[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
From
Date
On Wed, 2012-02-22 at 09:19 +0100, Indan Zupancic wrote:
[...]
> 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.
>
> Advantages:
>
> - Filters don't have to check the arch every syscall entry.
>
> - Secure by default. Filters don't have to do anything arch specific to
> be secure, no surprises possible.
>
> - If a new arch comes into existence, there is no chance of old filters
> becoming buggy and insecure. This is especially true for archs that
> had only one mode, but added another one later on: Old filters had no
> need to check the mode at all.
[...]

What about when there are multiple layers of restrictions? So long as
any one layer covers the new architecture, there is no default-deny even
though the other layers might not cover it.

I would have thought the way to make sure the architecture is always
checked is to pack it together with the syscall number.

Ben.

--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.



\
 
 \ /
  Last update: 2012-02-22 15:27    [from the cache]
©2003-2011 Jasper Spaans