[PATCH AUTOSEL for 4.9 081/190] qlcnic: fix unchecked return value

[Sasha Levin]

From: Pan Bian <bianpan2016@xxxxxxx>

[ Upstream commit 91ec701a553cb3de470fd471c6fefe3ad1125455 ]

Function pci_find_ext_capability() may return 0, which is an invalid
address. In function qlcnic_sriov_virtid_fn(), its return value is used
without validation. This may result in invalid memory access bugs. This
patch fixes the bug.

Signed-off-by: Pan Bian <bianpan2016@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c
index d7107055ec60..2f656f395f39 100644
--- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c
+++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c
@@ -128,6 +128,8 @@ static int qlcnic_sriov_virtid_fn(struct qlcnic_adapter *adapter, int vf_id)
 		return 0;
 
 	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
+	if (!pos)
+		return 0;
 	pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
 	pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
 
-- 
2.14.1