Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 037/108] net: phy: Fix PHY module checks and NULL deref in phy_attach_direct() | Date | Thu, 15 Jun 2017 19:52:43 +0200 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Florian Fainelli <f.fainelli@gmail.com>
[ Upstream commit 6d9f66ac7fec2a6ccd649e5909806dfe36f1fc25 ]
The Generic PHY drivers gets assigned after we checked that the current PHY driver is NULL, so we need to check a few things before we can safely dereference d->driver. This would be causing a NULL deference to occur when a system binds to the Generic PHY driver. Update phy_attach_direct() to do the following:
- grab the driver module reference after we have assigned the Generic PHY drivers accordingly, and remember we came from the generic PHY path
- update the error path to clean up the module reference in case the Generic PHY probe function fails
- split the error path involving phy_detacht() to avoid double free/put since phy_detach() does all the clean up
- finally, have phy_detach() drop the module reference count before we call device_release_driver() for the Generic PHY driver case
Fixes: cafe8df8b9bc ("net: phy: Fix lack of reference count on PHY driver") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/net/phy/phy_device.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)
--- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -860,6 +860,7 @@ int phy_attach_direct(struct net_device struct module *ndev_owner = dev->dev.parent->driver->owner; struct mii_bus *bus = phydev->mdio.bus; struct device *d = &phydev->mdio.dev; + bool using_genphy = false; int err; /* For Ethernet device drivers that register their own MDIO bus, we @@ -872,11 +873,6 @@ int phy_attach_direct(struct net_device return -EIO; } - if (!try_module_get(d->driver->owner)) { - dev_err(&dev->dev, "failed to get the device driver module\n"); - return -EIO; - } - get_device(d); /* Assume that if there is no driver, that it doesn't @@ -890,12 +886,22 @@ int phy_attach_direct(struct net_device d->driver = &genphy_driver[GENPHY_DRV_1G].mdiodrv.driver; + using_genphy = true; + } + + if (!try_module_get(d->driver->owner)) { + dev_err(&dev->dev, "failed to get the device driver module\n"); + err = -EIO; + goto error_put_device; + } + + if (using_genphy) { err = d->driver->probe(d); if (err >= 0) err = device_bind_driver(d); if (err) - goto error; + goto error_module_put; } if (phydev->attached_dev) { @@ -931,8 +937,14 @@ int phy_attach_direct(struct net_device return err; error: - put_device(d); + /* phy_detach() does all of the cleanup below */ + phy_detach(phydev); + return err; + +error_module_put: module_put(d->driver->owner); +error_put_device: + put_device(d); if (ndev_owner != bus->owner) module_put(bus->owner); return err; @@ -993,6 +1005,8 @@ void phy_detach(struct phy_device *phyde phydev->attached_dev = NULL; phy_suspend(phydev); + module_put(phydev->mdio.dev.driver->owner); + /* If the device had no specific driver before (i.e. - it * was using the generic driver), we unbind the device * from the generic driver so that there's a chance a @@ -1013,7 +1027,6 @@ void phy_detach(struct phy_device *phyde bus = phydev->mdio.bus; put_device(&phydev->mdio.dev); - module_put(phydev->mdio.dev.driver->owner); if (ndev_owner != bus->owner) module_put(bus->owner); }
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