Re: [PATCH 2/3] [RFC] seccomp: give BPF x32 bit when restoring x32 filter

From: H. Peter Anvin
Date: Fri Jul 11 2014 - 12:14:26 EST

On 07/11/2014 09:11 AM, Paul Moore wrote:
> On Thursday, July 10, 2014 09:06:02 PM H. Peter Anvin wrote:
>> Incidentally: do seccomp users know that on an x86-64 system you can
>> recevie system calls from any of the x86 architectures, regardless of
>> how the program is invoked? (This is unusual, so normally denying those
>> "alien" calls is the right thing to do.)
> I obviously can't speak for all seccomp users, but libseccomp handles this by
> checking the seccomp_data->arch value at the start of the filter and killing
> (by default) any non-native architectures. If you want, you can change this
> default behavior or add support for other architectures (e.g. create a filter
> that allows both x86-64 and x32 but disallows x86, or any combination of the
> three for that matter).

OK, that seems reasonable.


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