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

From: Peter Kosyh <p.kosyh@gmail.com>
To: p.kosyh@gmail.com
Cc: davem@davemloft.net, David Ahern <dsa@cumulusnetworks.com>,
	Shrijeet Mukherjee <shrijeet@gmail.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] Signed-off-by: Peter Kosyh <p.kosyh@gmail.com>
Date: Thu, 18 Jul 2019 13:26:55 +0300	[thread overview]
Message-ID: <20190718102655.17619-1-p.kosyh@gmail.com> (raw)

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, 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@gmail.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..7c0200bc46f9 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;
 		return vrf_process_v4_outbound(skb, dev);
 	case htons(ETH_P_IPV6):
+		if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct ipv6hdr)))
+			break;
 		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)
-- 
2.11.0

