Subject: [PATCH AUTOSEL 4.20 247/304] i40e: define proper net_device::neigh_priv_len

From: Sasha Levin <[email-masked]>
Date: Mon, 28 Jan 2019 10:42:44 -0500

From: Konstantin Khorenko <[email-masked]>

[ Upstream commit 31389b53b3e0b535867af9090a5d19ec64768d55 ]

Out of bound read reported by KASan.

i40iw_net_event() reads unconditionally 16 bytes from
neigh->primary_key while the memory allocated for
"neighbour" struct is evaluated in neigh_alloc() as

  tbl->entry_size + dev->neigh_priv_len

where "dev" is a net_device.

But the driver does not setup dev->neigh_priv_len and
we read beyond the neigh entry allocated memory,
so the patch in the next mail fixes this.

Signed-off-by: Konstantin Khorenko <[email-masked]>
Tested-by: Andrew Bowers <[email-masked]>
Signed-off-by: Jeff Kirsher <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 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 419cf3faada6..f97c3d5ab884 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -12339,6 +12339,9 @@ 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 */
-- 
2.19.1