net/fm10k/base: improve VF multi-bit VLAN update requests

The VF uses a multi-bit update request to clear unused VLANs whenever it
resets. However, an accident in a previous refactor broke multi-bit
updates for VFs, due to misreading a comment in fm10k_vf.c and
attempting to reduce code duplication. The problem occurs because
a multi-bit request has a non-zero length, and the PF would simply drop
any request with the upper 16 bits set. In addition, a multi-bit vlan
update does not have a concept for "VLAN 0" as the single bit update
does.

A previous revision of this patch resolved the issue by simply removing
the upper 16 bit check and the iov_select_vid checks. However, this would
remove the checks for default VID and for ensuring no other VLANs can be
enabled except pf_vid when it has been set. To resolve that issue, this
revision uses the iov_select_vid when we have a single-bit update, and
denies any multi-bit update when the VLAN was administratively set by
the PF. This should be ok since the PF properly updates VLAN_TABLE when
it assigns the PF vid. This ensures that requests to add or "remove" the
PF vid work as expected, but a rogue VF could not use the multi-bit
update as a loophole to attempt receiving traffic on other VLANs.

Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>

diff --git a/drivers/net/fm10k/base/fm10k_pf.c b/drivers/net/fm10k/base/fm10k_pf.c
index 878d46e..4c075b6 100644 (file)
--- a/drivers/net/fm10k/base/fm10k_pf.c
+++ b/drivers/net/fm10k/base/fm10k_pf.c
@@ -1271,18 +1271,32 @@ s32 fm10k_iov_msg_mac_vlan_pf(struct fm10k_hw *hw, u32 **results,
                if (err)
                        return err;
 
-               /* verify upper 16 bits are zero */
-               if (vid >> 16)
-                       return FM10K_ERR_PARAM;
-
                set = !(vid & FM10K_VLAN_CLEAR);
                vid &= ~FM10K_VLAN_CLEAR;
 
-               err = fm10k_iov_select_vid(vf_info, (u16)vid);
-               if (err < 0)
-                       return err;
+               /* if the length field has been set, this is a multi-bit
+                * update request. For multi-bit requests, simply disallow
+                * them when the pf_vid has been set. In this case, the PF
+                * should have already cleared the VLAN_TABLE, and if we
+                * allowed them, it could allow a rogue VF to receive traffic
+                * on a VLAN it was not assigned. In the single-bit case, we
+                * need to modify requests for VLAN 0 to use the default PF or
+                * SW vid when assigned.
+                */
 
-               vid = err;
+               if (vid >> 16) {
+                       /* prevent multi-bit requests when PF has
+                        * administratively set the VLAN for this VF
+                        */
+                       if (vf_info->pf_vid)
+                               return FM10K_ERR_PARAM;
+               } else {
+                       err = fm10k_iov_select_vid(vf_info, (u16)vid);
+                       if (err < 0)
+                               return err;
+
+                       vid = err;
+               }
 
                /* update VSI info for VF in regards to VLAN table */
                err = hw->mac.ops.update_vlan(hw, vid, vf_info->vsi, set);