The list iterator in a list_for_each_entry() loop can never be NULL.
If the loop exits without hitting a break then the iterator points
to an offset off the list head and dereferencing it is an out of
bounds access.
Before we transitioned to using list_for_each_entry() loops, then
it was possible for "entry" to be NULL and the comments mention
this. I have updated the comments to match the new code.
Fixes: c1fec890458a ("ethernet/intel: Use list_for_each_entry() helper")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
.../net/ethernet/intel/ixgbe/ixgbe_sriov.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
index 4c6e2a485d8e..a703ba975205 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
@@ -639,6 +639,7 @@ static int ixgbe_set_vf_macvlan(struct ixgbe_adapter *adapter,
int vf, int index, unsigned char *mac_addr)
{
struct vf_macvlans *entry;
+ bool found = false;
int retval = 0;
if (index <= 1) {
@@ -660,22 +661,22 @@ static int ixgbe_set_vf_macvlan(struct ixgbe_adapter *adapter,
if (!index)
return 0;
- entry = NULL;
-
list_for_each_entry(entry, &adapter->vf_mvs.l, l) {
- if (entry->free)
+ if (entry->free) {
+ found = true;
break;
+ }
}
/*
* If we traversed the entire list and didn't find a free entry
- * then we're out of space on the RAR table. Also entry may
- * be NULL because the original memory allocation for the list
- * failed, which is not fatal but does mean we can't support
- * VF requests for MACVLAN because we couldn't allocate
- * memory for the list management required.
+ * then we're out of space on the RAR table. It's also possible
+ * for the &adapter->vf_mvs.l list to be empty because the original
+ * memory allocation for the list failed, which is not fatal but does
+ * mean we can't support VF requests for MACVLAN because we couldn't
+ * allocate memory for the list management required.
*/
- if (!entry || !entry->free)
+ if (!found)
return -ENOSPC;
retval = ixgbe_add_mac_filter(adapter, mac_addr, vf);
--
2.39.2
