i40e: potential array underflow in i40e_vc_process_vf_msg()

commit c243e96335c56e56dcf6a00593104554fb06b689 upstream.

If "vf_id" is smaller than hw->func_caps.vf_base_id then it leads to
an array underflow of the pf->vf[] array.  This is unlikely to happen
unless the hardware is bad, but it's a small change and it silences a
static checker warning.

Fixes: 7efa84b7abc1 ('i40e: support VFs on PFs other than 0')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
index b9d1c1c8ca5a69f0d4d801f3cba0e4bc960ab46a..178506a201d530fec3168ce7343fe787c2c4c43a 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
@@ -1776,7 +1776,7 @@ int i40e_vc_process_vf_msg(struct i40e_pf *pf, u16 vf_id, u32 v_opcode,
                           u32 v_retval, u8 *msg, u16 msglen)
 {
        struct i40e_hw *hw = &pf->hw;
-       int local_vf_id = vf_id - hw->func_caps.vf_base_id;
+       unsigned int local_vf_id = vf_id - hw->func_caps.vf_base_id;
        struct i40e_vf *vf;
        int ret;