Commit bc0e610a authored by Jianglei Nie's avatar Jianglei Nie Committed by Jakub Kicinski
Browse files

net: arc_emac: Fix use after free in arc_mdio_probe() 



If bus->state is equal to MDIOBUS_ALLOCATED, mdiobus_free(bus) will free
the "bus". But bus->name is still used in the next line, which will lead
to a use after free.

We can fix it by putting the name in a local variable and make the
bus->name point to the rodata section "name",then use the name in the
error message without referring to bus to avoid the uaf.

Fixes: 95b5fc03 ("net: arc_emac: Make use of the helper function dev_err_probe()")
Signed-off-by: default avatarJianglei Nie <niejianglei2021@163.com>
Link: https://lore.kernel.org/r/20220309121824.36529-1-niejianglei2021@163.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 633593a8

drivers/net/ethernet/arc/emac_mdio.c

+3 −2
Original line number Diff line number Diff line
@@ -132,6 +132,7 @@ int arc_mdio_probe(struct arc_emac_priv *priv) 
{

	struct arc_emac_mdio_bus_data *data = &priv->bus_data;

	struct device_node *np = priv->dev->of_node;

	const char *name = "Synopsys MII Bus";

	struct mii_bus *bus;

	int error;
@@ -142,7 +143,7 @@ int arc_mdio_probe(struct arc_emac_priv *priv) 
	priv->bus = bus;

	bus->priv = priv;

	bus->parent = priv->dev;

	bus->name = "Synopsys MII Bus";

	bus->name = name;

	bus->read = &arc_mdio_read;

	bus->write = &arc_mdio_write;

	bus->reset = &arc_mdio_reset;
@@ -167,7 +168,7 @@ int arc_mdio_probe(struct arc_emac_priv *priv) 
	if (error) {

		mdiobus_free(bus);

		return dev_err_probe(priv->dev, error,

				     "cannot register MDIO bus %s\n", bus->name);

				     "cannot register MDIO bus %s\n", name);

	}



	return 0;