i40evf: dereference vsi after vsi has been null checked

Message ID 20170320120303.32284-1-colin.king@canonical.com
State Accepted
Delegated to: Jeff Kirsher
Headers show

Commit Message

Colin King March 20, 2017, 12:03 p.m.
From: Colin Ian King <colin.king@canonical.com>

vsi is being dereferenced before the vsi null check; if vsi is
null we end up with a null pointer dereference.  Fix this by
performing vsi deference after the vsi null check.  Also remove
the need for using adapter by using vsi->back->cinst.

Detected by CoverityScan, CID#1419696, CID#1419697
("Dereference before null check")

Fixes: ed0e894de7c133 ("i40evf: add client interface")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/ethernet/intel/i40evf/i40evf_client.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Comments

Bowers, AndrewX March 21, 2017, 11:31 p.m. | #1
> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@lists.osuosl.org] On
> Behalf Of Colin King
> Sent: Monday, March 20, 2017 5:03 AM
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com>; intel-wired-
> lan@lists.osuosl.org; netdev@vger.kernel.org
> Cc: kernel-janitors@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: [Intel-wired-lan] [PATCH] i40evf: dereference vsi after vsi has been
> null checked
> 
> From: Colin Ian King <colin.king@canonical.com>
> 
> vsi is being dereferenced before the vsi null check; if vsi is null we end up
> with a null pointer dereference.  Fix this by performing vsi deference after
> the vsi null check.  Also remove the need for using adapter by using vsi-
> >back->cinst.
> 
> Detected by CoverityScan, CID#1419696, CID#1419697 ("Dereference before
> null check")
> 
> Fixes: ed0e894de7c133 ("i40evf: add client interface")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/net/ethernet/intel/i40evf/i40evf_client.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>

Patch

diff --git a/drivers/net/ethernet/intel/i40evf/i40evf_client.c b/drivers/net/ethernet/intel/i40evf/i40evf_client.c
index 5b43e5b6e2eb..a579b2a5bd37 100644
--- a/drivers/net/ethernet/intel/i40evf/i40evf_client.c
+++ b/drivers/net/ethernet/intel/i40evf/i40evf_client.c
@@ -34,12 +34,12 @@  static struct i40e_ops i40evf_lan_ops = {
  **/
 void i40evf_notify_client_message(struct i40e_vsi *vsi, u8 *msg, u16 len)
 {
-	struct i40evf_adapter *adapter = vsi->back;
-	struct i40e_client_instance *cinst = adapter->cinst;
+	struct i40e_client_instance *cinst;
 
 	if (!vsi)
 		return;
 
+	cinst = vsi->back->cinst;
 	if (!cinst || !cinst->client || !cinst->client->ops ||
 	    !cinst->client->ops->virtchnl_receive) {
 		dev_dbg(&vsi->back->pdev->dev,
@@ -58,12 +58,13 @@  void i40evf_notify_client_message(struct i40e_vsi *vsi, u8 *msg, u16 len)
  **/
 void i40evf_notify_client_l2_params(struct i40e_vsi *vsi)
 {
-	struct i40evf_adapter *adapter = vsi->back;
-	struct i40e_client_instance *cinst = adapter->cinst;
+	struct i40e_client_instance *cinst;
 	struct i40e_params params;
 
 	if (!vsi)
 		return;
+
+	cinst = vsi->back->cinst;
 	memset(&params, 0, sizeof(params));
 	params.mtu = vsi->netdev->mtu;
 	params.link_up = vsi->back->link_up;