[PATCH 4.9 141/223] vrf: make sure skb->data contains ip header to make routing

Greg Kroah-Hartman
2019-08-02T09:46:18Z

From: Peter Kosyh <p.kosyh@gmail.com>

[ Upstream commit 107e47cc80ec37cb332bd41b22b1c7779e22e018 ]

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).

Case:

1) igb driver from intel.
2) Packet size is greater then 255.
3) MPLS forwards to VRF device.

So, patch adds pskb_may_pull() calls in vrf_process_v4/v6_outbound()
functions.

Signed-off-by: Peter Kosyh <p.kosyh@gmail.com>
Reviewed-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/vrf.c | 58 ++++++++++++++++++++++++++++++++----------------------
1 file changed, 35 insertions(+), 23 deletions(-)

--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -153,23 +153,29 @@ static int vrf_ip6_local_out(struct net
static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
struct net_device *dev)
{
- const struct ipv6hdr *iph = ipv6_hdr(skb);
+ const struct ipv6hdr *iph;
struct net *net = dev_net(skb->dev);
- struct flowi6 fl6 = {
- /* needed to match OIF rule */
- .flowi6_oif = dev->ifindex,
- .flowi6_iif = LOOPBACK_IFINDEX,
- .daddr = iph->daddr,
- .saddr = iph->saddr,
- .flowlabel = ip6_flowinfo(iph),
- .flowi6_mark = skb->mark,
- .flowi6_proto = iph->nexthdr,
- .flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF,
- };
+ struct flowi6 fl6;
int ret = NET_XMIT_DROP;
struct dst_entry *dst;
struct dst_entry *dst_null = &net->ipv6.ip6_null_entry->dst;

+ if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct ipv6hdr)))
+ goto err;
+
+ iph = ipv6_hdr(skb);
+
+ memset(&fl6, 0, sizeof(fl6));
+ /* needed to match OIF rule */
+ fl6.flowi6_oif = dev->ifindex;
+ fl6.flowi6_iif = LOOPBACK_IFINDEX;
+ fl6.daddr = iph->daddr;
+ fl6.saddr = iph->saddr;
+ fl6.flowlabel = ip6_flowinfo(iph);
+ fl6.flowi6_mark = skb->mark;
+ fl6.flowi6_proto = iph->nexthdr;
+ fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;
+
dst = ip6_route_output(net, NULL, &fl6);
if (dst == dst_null)
goto err;
@@ -257,21 +263,27 @@ static int vrf_ip_local_out(struct net *
static netdev_tx_t vrf_process_v4_outbound(struct sk_buff *skb,
struct net_device *vrf_dev)
{
- struct iphdr *ip4h = ip_hdr(skb);
+ struct iphdr *ip4h;
int ret = NET_XMIT_DROP;
- struct flowi4 fl4 = {
- /* needed to match OIF rule */
- .flowi4_oif = vrf_dev->ifindex,
- .flowi4_iif = LOOPBACK_IFINDEX,
- .flowi4_tos = RT_TOS(ip4h->tos),
- .flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_SKIP_NH_OIF,
- .flowi4_proto = ip4h->protocol,
- .daddr = ip4h->daddr,
- .saddr = ip4h->saddr,
- };
+ struct flowi4 fl4;
struct net *net = dev_net(vrf_dev);
struct rtable *rt;

+ if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct iphdr)))
+ goto err;
+
+ ip4h = ip_hdr(skb);
+
+ memset(&fl4, 0, sizeof(fl4));
+ /* needed to match OIF rule */
+ fl4.flowi4_oif = vrf_dev->ifindex;
+ fl4.flowi4_iif = LOOPBACK_IFINDEX;
+ fl4.flowi4_tos = RT_TOS(ip4h->tos);
+ fl4.flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_SKIP_NH_OIF;
+ fl4.flowi4_proto = ip4h->protocol;
+ fl4.daddr = ip4h->daddr;
+ fl4.saddr = ip4h->saddr;
+
rt = ip_route_output_flow(net, &fl4, NULL);
if (IS_ERR(rt))
goto err;