[PATCH 5.15 048/120] net: phy: fix null-ptr-deref while probe() failed

Greg Kroah-Hartman
2022-12-05T19:39:14Z

From: Yang Yingliang <yangyingliang@huawei.com>

[ Upstream commit 369eb2c9f1f72adbe91e0ea8efb130f0a2ba11a6 ]

I got a null-ptr-deref report as following when doing fault injection test:

BUG: kernel NULL pointer dereference, address: 0000000000000058
Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 253 Comm: 507-spi-dm9051 Tainted: G B N 6.1.0-rc3+
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:klist_put+0x2d/0xd0
Call Trace:
<TASK>
klist_remove+0xf1/0x1c0
device_release_driver_internal+0x23e/0x2d0
bus_remove_device+0x1bd/0x240
device_del+0x357/0x770
phy_device_remove+0x11/0x30
mdiobus_unregister+0xa5/0x140
release_nodes+0x6a/0xa0
devres_release_all+0xf8/0x150
device_unbind_cleanup+0x19/0xd0

//probe path:
phy_device_register()
device_add()

phy_connect
phy_attach_direct() //set device driver
probe() //it's failed, driver is not bound
device_bind_driver() // probe failed, it's not called

//remove path:
phy_device_remove()
device_del()
device_release_driver_internal()
__device_release_driver() //dev->drv is not NULL
klist_remove() <- knode_driver is not added yet, cause null-ptr-deref

In phy_attach_direct(), after setting the 'dev->driver', probe() fails,
device_bind_driver() is not called, so the knode_driver->n_klist is not
set, then it causes null-ptr-deref in __device_release_driver() while
deleting device. Fix this by setting dev->driver to NULL in the error
path in phy_attach_direct().

Fixes: e13934563db0 ("[PATCH] PHY Layer fixup")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/phy/phy_device.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index c5b92ffaffb9..1dd521c99725 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1518,6 +1518,7 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,

error_module_put:
module_put(d->driver->owner);
+ d->driver = NULL;
error_put_device:
put_device(d);
if (ndev_owner != bus->owner)
--
2.35.1