[Devel] [PATCH vz7] drivers/net/i40e: define proper net_device::neigh_priv_len

[Konstantin Khorenko]

Reported by KASan.

i40iw_net_event() unconditionally reads 16 bytes from
neighbour::priv_key on neigh entry update, but memory evaluated
for arp entry on allocation at neigh_event_ns() is evaluated as

	tbl->entry_size + dev->neigh_priv_len

and neigh_priv_len is not inited by the driver.

Fix that.

net_device allocation stack:

alloc_netdev_mqs
 alloc_etherdev_mqs_rh
  i40e_vsi_setup
   i40e_setup_pf_switch
    i40e_probe

neigh entry allocation stack:

__kmalloc
 __neigh_create
  neigh_event_ns
   arp_process
    arp_rcv
     __netif_receive_skb_core
      __netif_receive_skb
       netif_receive_skb_internal
        napi_gro_receive
         i40e_clean_rx_irq
          i40e_napi_poll
           net_rx_action
            __do_softirq

reading 16 bytes from neighbour::priv_key stack:

i40iw_copy_ip_ntohl
 i40iw_net_event
  notifier_call_chain
   atomic_notifier_call_chain
    call_netevent_notifiers
     neigh_update
      neigh_event_ns
       arp_process
        arp_rcv
         __netif_receive_skb_core
          __netif_receive_skb
           netif_receive_skb_internal
            napi_gro_receive
             i40e_clean_rx_irq
              i40e_napi_poll
               net_rx_action
                __do_softirq

https://pmc.acronis.com/browse/VSTOR-17918

Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 6596fb22ab7c..1a3df2eaf7dd 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -9606,6 +9606,9 @@ static int i40e_config_netdev(struct i40e_vsi *vsi)
 	ether_addr_copy(netdev->dev_addr, mac_addr);
 	ether_addr_copy(netdev->perm_addr, mac_addr);
 
+	/* i40iw_net_event() reads 16 bytes from neigh->primary_key */
+	netdev->neigh_priv_len = sizeof(u32) * 4;
+
 	netdev->priv_flags |= IFF_UNICAST_FLT;
 	netdev->priv_flags |= IFF_SUPP_NOFCS;
 	/* Setup netdev TC information */
-- 
2.15.1