Re: [libseccomp-discuss] allowing select() fails in i686

[Paul M. <pm...@re...>]

On Tuesday, January 27, 2015 12:13:15 PM Nikos Mavrogiannopoulos wrote:
> ----- Original Message -----
> 
> > On Tuesday, January 27, 2015 04:45:52 PM Nikos Mavrogiannopoulos wrote:
> > > Hello,
> > > 
> > > The attached program as far as I understand creates a filter which
> > > 
> > > allows select(). That works well on my x86-64:
> > > $ gcc test.c -lseccomp;./a.out
> > > all ok
> > > 
> > > However, if I run the same thing under i686 emulation, I have:
> > > $ gcc -m32 test.c -lseccomp;./a.out
> > > select is blocked!
> > 
> > Since you are running on an x86_64 system, you probably want to explicitly
> > add support for the x86 ABI if you are interested in creating a filter
> > that works on both x86_64 and x86.  This is probably not strictly
> > necessary if you are certain that you are linking to a properly build
> > native x86 library, but I can't be certain based on what you've posted.
> 
> Yes, I'm linking using the Fedora's i686 library. I should have mentioned
> that this is a reproducer for an issue reported to me:
> http://lists.infradead.org/pipermail/openconnect-devel/2015-January/002640.
> html I have no i686 available to me, that's why I reproduce that way.
> 
> > > Note that allow others calls (e.g., write) are properly executed as
> > > expected.
> > 
> > Have you verified this via strace, or similar?
> 
> I see the output on my screen so write worked :) Running it with strace
> shows the expected result.

Yes, of course.  Sorry about that :)

Did you try adding the x86 ABI to the filter?  I'm curious if that resolves 
the problem.

-- 
paul moore
security @ redhat