From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pablo Neira Ayuso <pablo@netfilter.org>
Subject: Re: [PATCH nf-next 2/4] netfilter: add BUILD_BUG_ON asserts for hook
 array sizes
Date: Wed, 22 Nov 2017 13:54:39 +0100
Message-ID: <20171122125439.GA563@salvia>
References: <20171113164107.11259-1-fw@strlen.de>
 <20171113164107.11259-3-fw@strlen.de>
 <20171122122025.GA29456@salvia>
 <20171122124410.GI24866@breakpoint.cc>
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Cc: netfilter-devel@vger.kernel.org
To: Florian Westphal <fw@strlen.de>
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On Wed, Nov 22, 2017 at 01:44:10PM +0100, Florian Westphal wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > Hi Florian,
> > 
> > On Mon, Nov 13, 2017 at 05:41:05PM +0100, Florian Westphal wrote:
> > > Check that the array hooks are not accessed out-of-bounds.
> > > Next patch will then reduce their sizes to reflect the number
> > > of hooks implemented for each family.
> > 
> > I'm hitting this here.
> > 
> > In file included from ./include/linux/kernel.h:10:0,
> >                  from ./include/linux/uio.h:12,
> >                  from ./include/linux/socket.h:8,
> >                  from net/decnet/dn_route.c:60:
> > In function ‘nf_hook.constprop’,
> >     inlined from ‘NF_HOOK.constprop’ at
> > ./include/linux/netfilter.h:279:6:
> > ./include/linux/compiler.h:319:38: error: call to
> > ‘__compiletime_assert_221’ declared with attribute error: BUILD_BUG_ON
> > failed: hook >= ARRAY_SIZE(net->nf.hooks_decnet)
> >   _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
> 
> Thanks for the report, I guess gcc doesn't follow inline trail
> or argument isn't known at compile time.
> 
> I'll add a contant_p() test as well in v2.

Side note: It's only happening with decnet.