[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <9daf8509e39cd20d9d806afdb425ad43af037f8d.camel@redhat.com>
Date: Tue, 28 Nov 2023 16:51:09 +0100
From: Paolo Abeni <pabeni@...hat.com>
To: Eric Dumazet <edumazet@...gle.com>, Shigeru Yoshida <syoshida@...hat.com>
Cc: davem@...emloft.net, dsahern@...nel.org, kuba@...nel.org,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net] ipv4: ip_gre: Handle skb_pull() failure in
ipgre_xmit()
On Tue, 2023-11-28 at 16:45 +0100, Eric Dumazet wrote:
> On Sun, Nov 26, 2023 at 4:17 PM Shigeru Yoshida <syoshida@...hat.com> wrote:
> >
> > In ipgre_xmit(), skb_pull() may fail even if pskb_inet_may_pull() returns
> > true. For example, applications can create a malformed packet that causes
> > this problem with PF_PACKET.
> >
> > This patch fixes the problem by dropping skb and returning from the
> > function if skb_pull() fails.
> >
> > Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
> > Signed-off-by: Shigeru Yoshida <syoshida@...hat.com>
> > ---
> > net/ipv4/ip_gre.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
> > index 22a26d1d29a0..95efa97cb84b 100644
> > --- a/net/ipv4/ip_gre.c
> > +++ b/net/ipv4/ip_gre.c
> > @@ -643,7 +643,8 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
> > /* Pull skb since ip_tunnel_xmit() needs skb->data pointing
> > * to gre header.
> > */
> > - skb_pull(skb, tunnel->hlen + sizeof(struct iphdr));
> > + if (!skb_pull(skb, tunnel->hlen + sizeof(struct iphdr)))
> > + goto free_skb;
> > skb_reset_mac_header(skb);
> >
> > if (skb->ip_summed == CHECKSUM_PARTIAL &&
> > --
>
>
> I have syszbot reports with an actual repro for this one.
Could you please share them? I could not find easily the reports in
https://syzkaller.appspot.com/upstream
Thanks,
Paolo
Powered by blists - more mailing lists