net: sparx5: Fix use after free inside sparx5_del_mact_entry

[ Upstream commit 89d72d4125e94aa3c2140fedd97ce07ba9e37674 ]

Based on the static analyzis of the code it looks like when an entry
from the MAC table was removed, the entry was still used after being
freed. More precise the vid of the mac_entry was used after calling
devm_kfree on the mac_entry.
The fix consists in first using the vid of the mac_entry to delete the
entry from the HW and after that to free it.

Fixes: b37a1bae742f ("net: sparx5: add mactable support")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240301080608.3053468-1-horatiu.vultur@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c b/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c
index 9a8e4f201eb1f7d3663c0c9a4be314d7bda2f334..6ba93fa984f26323e4bece09acc846acf69ca76f 100644 (file)
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_mactable.c
@@ -344,10 +344,10 @@ int sparx5_del_mact_entry(struct sparx5 *sparx5,
                                 list) {
                if ((vid == 0 || mact_entry->vid == vid) &&
                    ether_addr_equal(addr, mact_entry->mac)) {
+                       sparx5_mact_forget(sparx5, addr, mact_entry->vid);
+
                        list_del(&mact_entry->list);
                        devm_kfree(sparx5->dev, mact_entry);
-
-                       sparx5_mact_forget(sparx5, addr, mact_entry->vid);
                }
        }
        mutex_unlock(&sparx5->mact_lock);