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From: Jeremy Sowden <jeremy@azazel.net>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Netfilter Devel <netfilter-devel@vger.kernel.org>
Subject: Re: [PATCH nft] evaluate: don't eval unary arguments.
Date: Mon, 27 Jan 2020 11:13:43 +0000	[thread overview]
Message-ID: <20200127111343.GB377617@azazel.net> (raw)
In-Reply-To: <20200127093304.pqqvrxgyzveemert@salvia>

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On 2020-01-27, at 10:33:04 +0100, Pablo Neira Ayuso wrote:
> On Sun, Jan 19, 2020 at 06:12:03PM +0000, Jeremy Sowden wrote:
> > When a unary expression is inserted to implement a byte-order
> > conversion, the expression being converted has already been
> > evaluated and so expr_evaluate_unary doesn't need to do so.  For
> > most types of expression, the double evaluation doesn't matter since
> > evaluation is idempotent.  However, in the case of payload
> > expressions which are munged during evaluation, it can cause
> > unexpected errors:
> >
> >   # nft add table ip t
> >   # nft add chain ip t c '{ type filter hook input priority filter; }'
> >   # nft add rule ip t c ip dscp set 'ip dscp | 0x10'
> >   Error: Value 252 exceeds valid range 0-63
> >   add rule ip t c ip dscp set ip dscp | 0x10
> >                               ^^^^^^^
>
> I'm still hitting this after applying this patch.
>
> nft add rule ip t c ip dscp set ip dscp or 0x10
> Error: Value 252 exceeds valid range 0-63
> add rule ip t c ip dscp set ip dscp or 0x10
>                             ^^^^^^
> Probably problem is somewhere else? I'm not sure why we can assume
> here that the argument of the unary expression should not be
> evaluated.

I'll take another look.

J.

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  reply	other threads:[~2020-01-27 11:57 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-19 18:12 [PATCH nft] evaluate: don't eval unary arguments Jeremy Sowden
2020-01-27  9:33 ` Pablo Neira Ayuso
2020-01-27 11:13   ` Jeremy Sowden [this message]
2020-01-28 18:49     ` Pablo Neira Ayuso
2020-02-04 11:02       ` Jeremy Sowden
2020-02-23 22:14       ` Jeremy Sowden
2020-02-23 22:23         ` Pablo Neira Ayuso
2020-02-23 22:34           ` Florian Westphal
2020-02-23 22:38             ` Pablo Neira Ayuso
2020-02-23 23:12               ` Florian Westphal
2020-02-24 12:36           ` Jeremy Sowden

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