phylib: fix potential use-after-free

[ Upstream commit cbda1b1668 ]

Commit bafbdd527d ("phylib: Add device reset GPIO support") added call
to phy_device_reset(phydev) after the put_device() call in phy_detach().

The comment before the put_device() call says that the phydev might go
away with put_device().

Fix potential use-after-free by calling phy_device_reset() before
put_device().

Fixes: bafbdd527d ("phylib: Add device reset GPIO support")
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20220119162748.32418-1-kabel@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Marek Behún 2022-01-19 17:27:48 +01:00 committed by Greg Kroah-Hartman
parent 218cccb521
commit f39027cbad

View file

@ -1433,6 +1433,9 @@ void phy_detach(struct phy_device *phydev)
phy_driver_is_genphy_10g(phydev))
device_release_driver(&phydev->mdio.dev);
/* Assert the reset signal */
phy_device_reset(phydev, 1);
/*
* The phydev might go away on the put_device() below, so avoid
* a use-after-free bug by reading the underlying bus first.
@ -1444,9 +1447,6 @@ void phy_detach(struct phy_device *phydev)
ndev_owner = dev->dev.parent->driver->owner;
if (ndev_owner != bus->owner)
module_put(bus->owner);
/* Assert the reset signal */
phy_device_reset(phydev, 1);
}
EXPORT_SYMBOL(phy_detach);