From bc0e610a6eb0d46e4123fafdbe5e6141d9fff3be Mon Sep 17 00:00:00 2001 From: Jianglei Nie Date: Wed, 9 Mar 2022 20:18:24 +0800 Subject: [PATCH] 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: 95b5fc03c189 ("net: arc_emac: Make use of the helper function dev_err_probe()") Signed-off-by: Jianglei Nie Link: https://lore.kernel.org/r/20220309121824.36529-1-niejianglei2021@163.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/arc/emac_mdio.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/arc/emac_mdio.c b/drivers/net/ethernet/arc/emac_mdio.c index 9acf589..87f40c2 100644 --- a/drivers/net/ethernet/arc/emac_mdio.c +++ b/drivers/net/ethernet/arc/emac_mdio.c @@ -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; -- 2.7.4