From 51a04ebf21122d5c76a716ecd9bfc33ea44b2b39 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Thu, 10 Feb 2022 19:40:17 +0200 Subject: [PATCH] net: dsa: mv88e6xxx: fix use-after-free in mv88e6xxx_mdios_unregister Since struct mv88e6xxx_mdio_bus *mdio_bus is the bus->priv of something allocated with mdiobus_alloc_size(), this means that mdiobus_free(bus) will free the memory backing the mdio_bus as well. Therefore, the mdio_bus->list element is freed memory, but we continue to iterate through the list of MDIO buses using that list element. To fix this, use the proper list iterator that handles element deletion by keeping a copy of the list element next pointer. Fixes: f53a2ce893b2 ("net: dsa: mv88e6xxx: don't use devres for mdiobus") Reported-by: Rafael Richter Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20220210174017.3271099-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski --- drivers/net/dsa/mv88e6xxx/chip.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index 659f295824069..8530dbe403f4d 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -3449,10 +3449,10 @@ out: static void mv88e6xxx_mdios_unregister(struct mv88e6xxx_chip *chip) { - struct mv88e6xxx_mdio_bus *mdio_bus; + struct mv88e6xxx_mdio_bus *mdio_bus, *p; struct mii_bus *bus; - list_for_each_entry(mdio_bus, &chip->mdios, list) { + list_for_each_entry_safe(mdio_bus, p, &chip->mdios, list) { bus = mdio_bus->bus; if (!mdio_bus->external) -- 2.39.5