netdev - Re: [PATCH] Signed-off-by: Peter Kosyh <p.kosyh@...il.com>

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Date:   Thu, 18 Jul 2019 08:02:45 -0600
From:   David Ahern <dsa@...ulusnetworks.com>
To:     Peter Kosyh <p.kosyh@...il.com>
Cc:     davem@...emloft.net, Shrijeet Mukherjee <shrijeet@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Signed-off-by: Peter Kosyh <p.kosyh@...il.com>

your subject line needs a proper Subject - a one-line summary of the
change starting with 'vrf:'. See examples from 'git log drivers/net/vrf.c'


On 7/18/19 3:41 AM, Peter Kosyh wrote:
> vrf_process_v4_outbound() and vrf_process_v6_outbound() do routing
> using ip/ipv6 addresses, but don't make sure the header is available in
> skb->data[] (skb_headlen() is less then header size).
> 
> The situation may occures while forwarding from MPLS layer to vrf, for
> example.

so the use case is a label pop with the nexthop as the VRF device?

> 
> So, this patch adds pskb_may_pull() calls in is_ip_tx_frame(), just before
> call to vrf_process_... functions.
> 
> Signed-off-by: Peter Kosyh <p.kosyh@...il.com>
> ---
>  drivers/net/vrf.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
> index 54edf8956a25..d552f29a58d1 100644
> --- a/drivers/net/vrf.c
> +++ b/drivers/net/vrf.c
> @@ -292,13 +292,16 @@ static netdev_tx_t is_ip_tx_frame(struct sk_buff *skb, struct net_device *dev)
>  {
>  	switch (skb->protocol) {
>  	case htons(ETH_P_IP):
> +		if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct iphdr))
> +			break;

that check goes in vrf_process_v4_outbound.

>  		return vrf_process_v4_outbound(skb, dev);
>  	case htons(ETH_P_IPV6):
> +		if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct ipv6hdr))
> +			break;

that check goes in vrf_process_v6_outbound

leave this higher level sorter untouched.

>  		return vrf_process_v6_outbound(skb, dev);
> -	default:
> -		vrf_tx_error(dev, skb);
> -		return NET_XMIT_DROP;
>  	}
> +	vrf_tx_error(dev, skb);
> +	return NET_XMIT_DROP;
>  }
>  
>  static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
>