2017-06-07 14:16:30

by Haishuang Yan

Subject: [PATCH 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv

When ip_tunnel_rcv fails, the tun_dst won't be freed, so move
skb_dst_set to begin and tun_dst would be freed by kfree_skb.

Signed-off-by: Haishuang Yan <[email protected]>
---
net/ipv4/ip_tunnel.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index b878ecb..27fc20f 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -386,6 +386,9 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
const struct iphdr *iph = ip_hdr(skb);
int err;

+ if (tun_dst)
+ skb_dst_set(skb, (struct dst_entry *)tun_dst);
+
#ifdef CONFIG_NET_IPGRE_BROADCAST
if (ipv4_is_multicast(iph->daddr)) {
tunnel->dev->stats.multicast++;
@@ -439,9 +442,6 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
skb->dev = tunnel->dev;
}

- if (tun_dst)
- skb_dst_set(skb, (struct dst_entry *)tun_dst);
-
gro_cells_receive(&tunnel->gro_cells, skb);
return 0;

--
1.8.3.1

2017-06-07 14:16:40

by Haishuang Yan

Subject: [PATCH 2/2] ip6_tunnel: fix potential issue in __ip6_tnl_rcv

When __ip6_tnl_rcv fails, the tun_dst won't be freed, so move
skb_dst_set to begin and tun_dst would be freed by kfree_skb.

Signed-off-by: Haishuang Yan <[email protected]>
---
net/ipv6/ip6_tunnel.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 9b37f97..bf45f1b 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -789,6 +789,9 @@ static int __ip6_tnl_rcv(struct ip6_tnl *tunnel, struct sk_buff *skb,
const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
int err;

+ if (tun_dst)
+ skb_dst_set(skb, (struct dst_entry *)tun_dst);
+
if ((!(tpi->flags & TUNNEL_CSUM) &&
(tunnel->parms.i_flags & TUNNEL_CSUM)) ||
((tpi->flags & TUNNEL_CSUM) &&
@@ -852,9 +855,6 @@ static int __ip6_tnl_rcv(struct ip6_tnl *tunnel, struct sk_buff *skb,

skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(tunnel->dev)));

- if (tun_dst)
- skb_dst_set(skb, (struct dst_entry *)tun_dst);
-
gro_cells_receive(&tunnel->gro_cells, skb);
return 0;

--
1.8.3.1

2017-06-07 14:50:01

by Eric Dumazet

Subject: Re: [PATCH 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv

On Wed, 2017-06-07 at 22:16 +0800, Haishuang Yan wrote:
> When ip_tunnel_rcv fails, the tun_dst won't be freed, so move
> skb_dst_set to begin and tun_dst would be freed by kfree_skb.
>
> Signed-off-by: Haishuang Yan <[email protected]>
> ---

Please add the missing Fixes: tag and CC author of the patch that added
this bug, so that he has a chance to comment and avoid future similar
bugs.

Thanks.

2017-06-08 00:10:17

by Haishuang Yan

Subject: Re: [PATCH 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv

> On 7 Jun 2017, at 10:48 PM, Eric Dumazet <[email protected]> wrote:
>
> On Wed, 2017-06-07 at 22:16 +0800, Haishuang Yan wrote:
>> When ip_tunnel_rcv fails, the tun_dst won't be freed, so move
>> skb_dst_set to begin and tun_dst would be freed by kfree_skb.
>>
>> Signed-off-by: Haishuang Yan <[email protected]>
>> ---
>
> Please add the missing Fixes: tag and CC author of the patch that added
> this bug, so that he has a chance to comment and avoid future similar
> bugs.
>
> Thanks.
>
>
>

Ok, I will add these information in v2 commit.
Thanks.