RE: [PATCH v3 net] ixgbe: check adapter->vfinfo before dereference

["Tantilov, Emil S" <emil.s.tantilov@intel.com>]

>-----Original Message-----
>From: Thierry Herbelot [mailto:thierry.herbelot@6wind.com]
>Sent: Wednesday, October 15, 2014 2:58 AM
>To: Kirsher, Jeffrey T; Brandeburg, Jesse; Allan, Bruce W;
>netdev@vger.kernel.org; Tantilov, Emil S
>Cc: Thierry Herbelot
>Subject: [PATCH v3 net] ixgbe: check adapter->vfinfo before dereference
>
>this protects against the following panic:
>(before a VF was actually created on p96p1 PF Ethernet port)
>
>ip link set p96p1 vf 0 spoofchk off
>BUG: unable to handle kernel NULL pointer dereference at 0000000000000052
>IP: [<ffffffffa044a1c1>]
>ixgbe_ndo_set_vf_spoofchk+0x51/0x150 [ixgbe]
>
>Signed-off-by: Thierry Herbelot <thierry.herbelot@6wind.com>
>---
>
>v2:
>  compilation fixes
>
>v3:
>  remove checks in functions where vfinfo is known not to be NULL
>  return -EINVAL as error code
>
> drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c |   42
>++++++++++++++++++++++--
> 1 file changed, 40 insertions(+), 2 deletions(-)

Actually looking into this a bit more, the check for vfinfo is not sufficient
because it does not protect against specifying vf that is outside of sriov_num_vfs range.

All of the ndo functions have a check for it except for ixgbevf_ndo_set_spoofcheck().

The following patch should be all we need to protect against this panic:

This patch adds a check to return -EINVAL when setting spoofcheck on
VF that is not configured.

Reported-by: Thierry Herbelot <thierry.herbelot@6wind.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
index 706fc69..97c85b8 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
@@ -1261,6 +1261,9 @@ int ixgbe_ndo_set_vf_spoofchk(struct net_device *netdev, int vf, bool setting)
 	struct ixgbe_hw *hw = &adapter->hw;
 	u32 regval;
 
+	if (vf >= adapter->num_vfs)
+		return -EINVAL;
+
 	adapter->vfinfo[vf].spoofchk_enabled = setting;
 
 	regval = IXGBE_READ_REG(hw, IXGBE_PFVFSPOOF(vf_target_reg));