[PATCH v3 net-next 1/2] net: ethernet: mtk_wed: fix some possible NULL pointer dereferences

[Lorenzo Bianconi]

Fix possible NULL pointer dereference in mtk_wed_detach routine checking
wo pointer is properly allocated before running mtk_wed_wo_reset() and
mtk_wed_wo_deinit().
Even if it is just a theoretical issue at the moment check wo pointer is
not NULL in mtk_wed_mcu_msg_update.
Moreover, honor mtk_wed_mcu_send_msg return value in mtk_wed_wo_reset()

Fixes: 799684448e3e ("net: ethernet: mtk_wed: introduce wed wo support")
Fixes: 4c5de09eb0d0 ("net: ethernet: mtk_wed: add configure wed wo support")
Signed-off-by: Lorenzo Bianconi <lorenzo at kernel.org>
---
 drivers/net/ethernet/mediatek/mtk_wed.c     | 13 ++++++++-----
 drivers/net/ethernet/mediatek/mtk_wed_mcu.c |  3 +++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_wed.c b/drivers/net/ethernet/mediatek/mtk_wed.c
index 06b6cc53fa02..4ef23eadd69e 100644
--- a/drivers/net/ethernet/mediatek/mtk_wed.c
+++ b/drivers/net/ethernet/mediatek/mtk_wed.c
@@ -174,9 +174,10 @@ mtk_wed_wo_reset(struct mtk_wed_device *dev)
 	mtk_wdma_tx_reset(dev);
 	mtk_wed_reset(dev, MTK_WED_RESET_WED);
 
-	mtk_wed_mcu_send_msg(wo, MTK_WED_MODULE_ID_WO,
-			     MTK_WED_WO_CMD_CHANGE_STATE, &state,
-			     sizeof(state), false);
+	if (mtk_wed_mcu_send_msg(wo, MTK_WED_MODULE_ID_WO,
+				 MTK_WED_WO_CMD_CHANGE_STATE, &state,
+				 sizeof(state), false))
+		return;
 
 	if (readx_poll_timeout(mtk_wed_wo_read_status, dev, val,
 			       val == MTK_WED_WOIF_DISABLE_DONE,
@@ -590,9 +591,11 @@ mtk_wed_detach(struct mtk_wed_device *dev)
 	mtk_wed_free_tx_rings(dev);
 
 	if (mtk_wed_get_rx_capa(dev)) {
-		mtk_wed_wo_reset(dev);
+		if (hw->wed_wo)
+			mtk_wed_wo_reset(dev);
 		mtk_wed_free_rx_rings(dev);
-		mtk_wed_wo_deinit(hw);
+		if (hw->wed_wo)
+			mtk_wed_wo_deinit(hw);
 	}
 
 	if (dev->wlan.bus_type == MTK_WED_BUS_PCIE) {
diff --git a/drivers/net/ethernet/mediatek/mtk_wed_mcu.c b/drivers/net/ethernet/mediatek/mtk_wed_mcu.c
index f9539e6233c9..6bad0d262f28 100644
--- a/drivers/net/ethernet/mediatek/mtk_wed_mcu.c
+++ b/drivers/net/ethernet/mediatek/mtk_wed_mcu.c
@@ -207,6 +207,9 @@ int mtk_wed_mcu_msg_update(struct mtk_wed_device *dev, int id, void *data,
 	if (dev->hw->version == 1)
 		return 0;
 
+	if (WARN_ON(!wo))
+		return -ENODEV;
+
 	return mtk_wed_mcu_send_msg(wo, MTK_WED_MODULE_ID_WO, id, data, len,
 				    true);
 }
-- 
2.38.1