From: Florian Westphal <fw@strlen.de>
To: Eric Dumazet <edumazet@google.com>
Cc: Florian Westphal <fw@strlen.de>,
"David S . Miller" <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
syzbot <syzkaller@googlegroups.com>
Subject: Re: [PATCH net] ipv6: drop incoming packets having a v4mapped source address
Date: Wed, 2 Oct 2019 23:54:17 +0200 [thread overview]
Message-ID: <20191002215417.GB13866@breakpoint.cc> (raw)
In-Reply-To: <CANn89iLsrAm80Snk9YzEASWtrskqWFpEU11Y253pt1S=75B4wA@mail.gmail.com>
Eric Dumazet <edumazet@google.com> wrote:
> > > @@ -223,6 +223,16 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
> > > if (ipv6_addr_is_multicast(&hdr->saddr))
> > > goto err;
> > >
> > > + /* While RFC4291 is not explicit about v4mapped addresses
> > > + * in IPv6 headers, it seems clear linux dual-stack
> > > + * model can not deal properly with these.
> > > + * Security models could be fooled by ::ffff:127.0.0.1 for example.
> > > + *
> > > + * https://tools.ietf.org/html/draft-itojun-v6ops-v4mapped-harmful-02
> > > + */
> > > + if (ipv6_addr_v4mapped(&hdr->saddr))
> > > + goto err;
> > > +
> >
> > Any reason to only consider ->saddr instead of checking daddr as well?
>
> I do not see reasons the packet should be accepted for sane configurations ?
Fair enough, thanks for explaining.
next prev parent reply other threads:[~2019-10-02 21:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-02 16:38 [PATCH net] ipv6: drop incoming packets having a v4mapped source address Eric Dumazet
2019-10-02 18:38 ` Florian Westphal
2019-10-02 18:47 ` Eric Dumazet
2019-10-02 21:54 ` Florian Westphal [this message]
2019-10-03 15:42 ` David Miller
2021-03-05 17:57 ` Jakub Kicinski
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