[PATCH net] vrf: Reset IPCB/IP6CB when processing outbound pkts in vrf dev xmit

[PATCH net] vrf: Reset IPCB/IP6CB when processing outbound pkts in vrf dev xmit

[Stephen Suryaputra]

IPCB/IP6CB need to be initialized when processing outbound v4 or v6 pkts
in the codepath of vrf device xmit function so that leftover garbage
doesn't cause futher code that uses the CB to incorrectly process the
pkt.

One occasion of the issue might occur when MPLS route uses the vrf
device as the outgoing device such as when the route is added using "ip
-f mpls route add <label> dev <vrf>" command.

The problems seems to exist since day one. Hence I put the day one
commits on the Fixes tags.

Fixes: 193125dbd8eb ("net: Introduce VRF device driver")
Fixes: 35402e313663 ("net: Add IPv6 support to VRF device")
Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
---
 drivers/net/vrf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index ccf677015d5b..131c745dc701 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -497,6 +497,7 @@ static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
 	/* strip the ethernet header added for pass through VRF device */
 	__skb_pull(skb, skb_network_offset(skb));
 
+	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 	ret = vrf_ip6_local_out(net, skb->sk, skb);
 	if (unlikely(net_xmit_eval(ret)))
 		dev->stats.tx_errors++;
@@ -579,6 +580,7 @@ static netdev_tx_t vrf_process_v4_outbound(struct sk_buff *skb,
 					       RT_SCOPE_LINK);
 	}
 
+	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 	ret = vrf_ip_local_out(dev_net(skb_dst(skb)->dev), skb->sk, skb);
 	if (unlikely(net_xmit_eval(ret)))
 		vrf_dev->stats.tx_errors++;
-- 
2.25.1

Re: [PATCH net] vrf: Reset IPCB/IP6CB when processing outbound pkts in vrf dev xmit

[David Ahern]

On 11/30/21 9:26 AM, Stephen Suryaputra wrote:
> IPCB/IP6CB need to be initialized when processing outbound v4 or v6 pkts
> in the codepath of vrf device xmit function so that leftover garbage
> doesn't cause futher code that uses the CB to incorrectly process the
> pkt.
> 
> One occasion of the issue might occur when MPLS route uses the vrf
> device as the outgoing device such as when the route is added using "ip
> -f mpls route add <label> dev <vrf>" command.
> 
> The problems seems to exist since day one. Hence I put the day one
> commits on the Fixes tags.
> 
> Fixes: 193125dbd8eb ("net: Introduce VRF device driver")
> Fixes: 35402e313663 ("net: Add IPv6 support to VRF device")
> Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
> ---
>  drivers/net/vrf.c | 2 ++
>  1 file changed, 2 insertions(+)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>

Re: [PATCH net] vrf: Reset IPCB/IP6CB when processing outbound pkts in vrf dev xmit

[Nicolas Dichtel]

Le 30/11/2021 à 17:26, Stephen Suryaputra a écrit :
> IPCB/IP6CB need to be initialized when processing outbound v4 or v6 pkts
> in the codepath of vrf device xmit function so that leftover garbage
> doesn't cause futher code that uses the CB to incorrectly process the
> pkt.
> 
> One occasion of the issue might occur when MPLS route uses the vrf
> device as the outgoing device such as when the route is added using "ip
> -f mpls route add <label> dev <vrf>" command.
> 
> The problems seems to exist since day one. Hence I put the day one
> commits on the Fixes tags.
> 
> Fixes: 193125dbd8eb ("net: Introduce VRF device driver")
> Fixes: 35402e313663 ("net: Add IPv6 support to VRF device")
> Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Cc: stable@vger.kernel.org

Thanks,
Nicolas

Re: [PATCH net] vrf: Reset IPCB/IP6CB when processing outbound pkts in vrf dev xmit

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 30 Nov 2021 11:26:37 -0500 you wrote:
> IPCB/IP6CB need to be initialized when processing outbound v4 or v6 pkts
> in the codepath of vrf device xmit function so that leftover garbage
> doesn't cause futher code that uses the CB to incorrectly process the
> pkt.
> 
> One occasion of the issue might occur when MPLS route uses the vrf
> device as the outgoing device such as when the route is added using "ip
> -f mpls route add <label> dev <vrf>" command.
> 
> [...]

Here is the summary with links:
  - [net] vrf: Reset IPCB/IP6CB when processing outbound pkts in vrf dev xmit
    https://git.kernel.org/netdev/net/c/ee201011c1e1

You are awesome, thank you!
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