From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Florian Westphal <fw@strlen.de>
Cc: netfilter-devel@vger.kernel.org,
"Maciej Żenczykowski" <zenczykowski@gmail.com>
Subject: Re: [PATCH v2 nft] parser: tcpopt: fix tcp option parsing with NUM + length field
Date: Tue, 5 Dec 2023 15:10:02 +0100 [thread overview]
Message-ID: <ZW8vOk8C3zTR3R8K@calendula> (raw)
In-Reply-To: <20231205131448.GB13832@breakpoint.cc>
On Tue, Dec 05, 2023 at 02:14:48PM +0100, Florian Westphal wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > On Tue, Dec 05, 2023 at 01:20:26PM +0100, Florian Westphal wrote:
> > > Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > > > > if (!desc) {
> > > > > - if (field != TCPOPT_COMMON_KIND || kind > 255)
> > > > > + if (kind > 255)
> > > > > return NULL;
> > > >
> > > > Another suggestion: Remove this NULL, it leaves lhs as NULL in the
> > > > relational. kind > 255 cannot ever happen, parser rejects numbers over
> > > > 255.
> > >
> > > We can also feed this via input from udata (typeof).
> > > So I'd rather not assert() or rely on bison checks.
> >
> > OK, but then NULL does not help either, that will crash on evaluation too.
> >
> > You could narrow down kind and field in tcpopt_expr_alloc() to uint8_t.
>
> Unfortunately, no. 'kind' is overloaded, SACK blocks 1/2/3/4 use values
> gt 255, see TCPOPT_KIND_SACK3 at end of enum tcpopt_kind.
OK, patch is fine then.
next prev parent reply other threads:[~2023-12-05 14:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-05 11:56 [PATCH v2 nft] parser: tcpopt: fix tcp option parsing with NUM + length field Florian Westphal
2023-12-05 12:07 ` Pablo Neira Ayuso
2023-12-05 12:20 ` Florian Westphal
2023-12-05 12:50 ` Pablo Neira Ayuso
2023-12-05 13:14 ` Florian Westphal
2023-12-05 14:10 ` Pablo Neira Ayuso [this message]
2023-12-06 7:58 ` Thomas Haller
2023-12-06 11:38 ` Florian Westphal
2023-12-06 11:50 ` Thomas Haller
2023-12-06 11:59 ` Florian Westphal
2023-12-06 12:04 ` Florian Westphal
2023-12-06 12:09 ` Thomas Haller
2023-12-06 12:16 ` Florian Westphal
2023-12-06 13:22 ` Thomas Haller
2023-12-06 13:24 ` Florian Westphal
2023-12-06 14:56 ` Thomas Haller
2023-12-06 14:19 ` Phil Sutter
2023-12-06 15:12 ` Thomas Haller
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