2017-06-08 00:58:25

by Haishuang Yan

Subject: [PATCH v2 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.

CC: Pravin B Shelar <[email protected]>
Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
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

2017-06-08 00:58:20

by Haishuang Yan

Subject: [PATCH v2 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.

CC: Alexei Starovoitov <[email protected]>
Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels")
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

2017-06-08 02:21:24

by Eric Dumazet

Subject: Re: [PATCH v2 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv

On Thu, 2017-06-08 at 08:57 +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.
>
> CC: Pravin B Shelar <[email protected]>
> Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
> Signed-off-by: Haishuang Yan <[email protected]>
> ---

Acked-by: Eric Dumazet <[email protected]>

Thanks a lot.

2017-06-08 02:25:19

by Pravin Shelar

Subject: Re: [PATCH v2 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv

On Wed, Jun 7, 2017 at 5:57 PM, Haishuang Yan
<[email protected]> 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.
>
> CC: Pravin B Shelar <[email protected]>
> Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
> 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);
> +
If dst is set so early, skb_scrub_packet() would remove the tunnel dst
reference.
It is better to call skb_dst_drop() from error code path.

> #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
>
>
>

2017-06-08 02:49:22

by Alexei Starovoitov

Subject: Re: [PATCH v2 2/2] ip6_tunnel: fix potential issue in __ip6_tnl_rcv

On Thu, Jun 08, 2017 at 08:57:56AM +0800, Haishuang Yan wrote:
> 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.
>
> CC: Alexei Starovoitov <[email protected]>
> Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels")
> Signed-off-by: Haishuang Yan <[email protected]>

Good catch. Thanks!
Acked-by: Alexei Starovoitov <[email protected]>

2017-06-08 03:07:59

by Haishuang Yan

Subject: Re: [PATCH v2 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv

> On 8 Jun 2017, at 10:13 AM, Pravin Shelar <[email protected]> wrote:
>
> On Wed, Jun 7, 2017 at 5:57 PM, Haishuang Yan
> <[email protected]> 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.
>>
>> CC: Pravin B Shelar <[email protected]>
>> Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
>> 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);
>> +
> If dst is set so early, skb_scrub_packet() would remove the tunnel dst
> reference.
> It is better to call skb_dst_drop() from error code path.

Yes, I will change it in v3 commit, thanks!

>
>> #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
>>
>>
>>
>

2017-06-08 03:15:17

by Eric Dumazet

Subject: Re: [PATCH v2 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv

On Wed, 2017-06-07 at 19:13 -0700, Pravin Shelar wrote:
> On Wed, Jun 7, 2017 at 5:57 PM, Haishuang Yan
> <[email protected]> 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.
> >
> > CC: Pravin B Shelar <[email protected]>
> > Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
> > 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);
> > +
> If dst is set so early, skb_scrub_packet() would remove the tunnel dst
> reference.
> It is better to call skb_dst_drop() from error code path.

Do we really want to keep a dst from another namespace if
skb_scrub_packet() is called with xnet=true ?

2017-06-08 04:06:50

by Pravin Shelar

Subject: Re: [PATCH v2 1/2] ip_tunnel: fix potential issue in ip_tunnel_rcv

On Wed, Jun 7, 2017 at 8:15 PM, Eric Dumazet <[email protected]> wrote:
> On Wed, 2017-06-07 at 19:13 -0700, Pravin Shelar wrote:
>> On Wed, Jun 7, 2017 at 5:57 PM, Haishuang Yan
>> <[email protected]> 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.
>> >
>> > CC: Pravin B Shelar <[email protected]>
>> > Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
>> > 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);
>> > +
>> If dst is set so early, skb_scrub_packet() would remove the tunnel dst
>> reference.
>> It is better to call skb_dst_drop() from error code path.
>
> Do we really want to keep a dst from another namespace if
> skb_scrub_packet() is called with xnet=true ?
>
tun_dst is allocated in same namespace. It is required for LWT to work.