From: Jakub Kicinski <kuba@kernel.org>
To: Kuniyuki Iwashima <kuniyu@google.com>
Cc: Eric Dumazet <edumazet@google.com>,
"David S . Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Willem de Bruijn <willemb@google.com>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Damiano Melotti <melotti@google.com>
Subject: Re: [PATCH net] tunnels: do not assume transport header in iptunnel_pmtud_check_icmp()
Date: Mon, 25 May 2026 11:20:11 -0700 [thread overview]
Message-ID: <20260525112011.38a93f49@kernel.org> (raw)
In-Reply-To: <CAAVpQUA=kJ-Ne0zDniRehpebv51MuBnvKcAL5DpT2ofk8Ad12A@mail.gmail.com>
On Sun, 24 May 2026 19:55:50 -0700 Kuniyuki Iwashima wrote:
> On Fri, May 22, 2026 at 4:55 AM Eric Dumazet <edumazet@google.com> wrote:
> >
> > In some cases, iptunnel_pmtud_check_icmp() can be called while
> > skb transport header is not set.
> >
> > This triggers an out-of-bound access, because
> > (typeof(skb->transport_header))~0U is 65535.
> >
> > Access the icmp header based on IPv4 network header,
> > after making sure icmp->type is present in skb linear part.
> >
> > Note that iptunnel_pmtud_check_icmpv6()) is fine.
> >
> > Fixes: 4cb47a8644cc ("tunnels: PMTU discovery support for directly bridged IP packets")
> > Reported-by: Damiano Melotti <melotti@google.com>
> > Signed-off-by: Eric Dumazet <edumazet@google.com>
>
> Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Are we okay with what sashiko is reporting?
If it's legit it may be better to fix in one series
next prev parent reply other threads:[~2026-05-25 18:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-22 11:55 [PATCH net] tunnels: do not assume transport header in iptunnel_pmtud_check_icmp() Eric Dumazet
2026-05-25 2:55 ` Kuniyuki Iwashima
2026-05-25 18:20 ` Jakub Kicinski [this message]
2026-05-25 18:41 ` Eric Dumazet
2026-05-25 18:54 ` Jakub Kicinski
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