Subject: [PATCH 1/3] net: dsa: lantiq_gswip: fix use-after-free on failed probe

From: Johan Hovold <[email-masked]>
Date: Wed, 16 Jan 2019 11:23:33 +0100

Make sure to disable and deregister the switch on late probe errors to
avoid use-after-free when the device-resource-managed switch is freed.

Fixes: 14fceff4771e ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")
Cc: stable <[email-masked]>	# 4.20
Cc: Hauke Mehrtens <[email-masked]>
Signed-off-by: Johan Hovold <[email-masked]>
---
 drivers/net/dsa/lantiq_gswip.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c
index 693a67f45bef..b06c41c98de9 100644
--- a/drivers/net/dsa/lantiq_gswip.c
+++ b/drivers/net/dsa/lantiq_gswip.c
@@ -1099,7 +1099,7 @@ static int gswip_probe(struct platform_device *pdev)
 		dev_err(dev, "wrong CPU port defined, HW only supports port: %i",
 			priv->hw_info->cpu_port);
 		err = -EINVAL;
-		goto mdio_bus;
+		goto disable_switch;
 	}
 
 	platform_set_drvdata(pdev, priv);
@@ -1109,6 +1109,9 @@ static int gswip_probe(struct platform_device *pdev)
 		 (version & GSWIP_VERSION_MOD_MASK) >> GSWIP_VERSION_MOD_SHIFT);
 	return 0;
 
+disable_switch:
+	gswip_mdio_mask(priv, GSWIP_MDIO_GLOB_ENABLE, 0, GSWIP_MDIO_GLOB);
+	dsa_unregister_switch(priv->ds);
 mdio_bus:
 	if (mdio_np)
 		mdiobus_unregister(priv->ds->slave_mii_bus);
-- 
2.20.1