4.9-stable review patch. If anyone has any objections, please let me know. ------------------ 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> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/qlogic/qlcnic/qlcnic_sriov_common.c | 2 ++ 1 file changed, 2 insertions(+) --- 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 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);