From: Hangbin Liu <liuhangbin@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev@vger.kernel.org, Stefano Brivio <sbrivio@redhat.com>,
wenxu <wenxu@ucloud.cn>, Alexei Starovoitov <ast@fb.com>,
"David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH net] tunnel: fix dev null pointer dereference when send pkg larger than mtu in collect_md mode
Date: Fri, 16 Aug 2019 11:24:18 +0800 [thread overview]
Message-ID: <20190816032418.GX18865@dhcp-12-139.nay.redhat.com> (raw)
In-Reply-To: <cb5b5d82-1239-34a9-23f5-1894a2ec92a2@gmail.com>
Hi Eric,
Thanks for the review.
On Thu, Aug 15, 2019 at 11:16:58AM +0200, Eric Dumazet wrote:
> > diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
> > index 38c02bb62e2c..c6713c7287df 100644
> > --- a/net/ipv4/ip_tunnel.c
> > +++ b/net/ipv4/ip_tunnel.c
> > @@ -597,6 +597,9 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
> > goto tx_error;
> > }
> >
> > + if (skb_dst(skb) && !skb_dst(skb)->dev)
> > + skb_dst(skb)->dev = rt->dst.dev;
> > +
>
>
> IMO this looks wrong.
> This dst seems shared.
If the dst is shared, it may cause some problem. Could you point me where the
dst may be shared possibly?
> Once set, we will reuse the same dev ?
If yes, how about just set the skb dst to rt->dst, as the
iptunnel_xmit would do later.
skb_dst_drop(skb);
skb_dst_set(skb, &rt->dst);
or do you have any other idea?
>
> If intended, why not doing this in __metadata_dst_init() instead of in the fast path ?
I'm afraid we couldn't do this, I didn't find a way to init dev in
__metadata_dst_init(). Do you?
Thanks
Hangbin
next prev parent reply other threads:[~2019-08-16 3:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-15 6:09 [PATCH net] tunnel: fix dev null pointer dereference when send pkg larger than mtu in collect_md mode Hangbin Liu
2019-08-15 9:16 ` Eric Dumazet
2019-08-16 3:24 ` Hangbin Liu [this message]
2019-08-16 4:01 ` Hangbin Liu
2019-08-16 8:23 ` Eric Dumazet
2019-08-16 10:51 ` Hangbin Liu
2019-08-19 7:53 ` [PATCHv2 0/2] " Hangbin Liu
2019-08-19 7:53 ` [PATCH 1/2] ipv4/icmp: fix rt dst dev null pointer dereference Hangbin Liu
2019-08-21 16:11 ` Julian Anastasov
2019-08-19 7:53 ` [PATCH 2/2] xfrm/xfrm_policy: fix dst dev null pointer dereference in collect_md mode Hangbin Liu
2019-08-20 19:20 ` [PATCHv2 0/2] fix dev null pointer dereference when send pkg larger than mtu " David Miller
2019-08-21 2:09 ` [PATCHv3 0/2] fix dev null pointer dereference when send packets " Hangbin Liu
2019-08-21 2:09 ` [PATCHv3 1/2] ipv4/icmp: fix rt dst dev null pointer dereference Hangbin Liu
2019-08-21 2:09 ` [PATCHv3 2/2] xfrm/xfrm_policy: fix dst dev null pointer dereference in collect_md mode Hangbin Liu
2019-08-22 14:19 ` [PATCHv4 0/2] fix dev null pointer dereference when send packets larger than mtu " Hangbin Liu
2019-08-22 14:19 ` [PATCHv4 net 1/2] ipv4/icmp: fix rt dst dev null pointer dereference Hangbin Liu
2019-08-22 18:46 ` Julian Anastasov
2019-08-23 22:32 ` Jonathan Lemon
2019-08-22 14:19 ` [PATCHv4 net 2/2] xfrm/xfrm_policy: fix dst dev null pointer dereference in collect_md mode Hangbin Liu
2019-08-23 22:30 ` Jonathan Lemon
2019-08-24 21:51 ` [PATCHv4 0/2] fix dev null pointer dereference when send packets larger than mtu " David Miller
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