CVE-2022-49021 net: phy: fix null-ptr-deref while probe() failed
A null pointer dereference in the Linux kernel network PHY driver can cause a system crash when device probing fails.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-49021?
CVE-2022-49021 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: phy: fix null-ptr-deref while probe() failed
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().
Weakness: CWE-476
Which versions are affected by CVE-2022-49021?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49021?
Apply the vendor's patch.
Is CVE-2022-49021 being exploited?
There is no known exploitation of CVE-2022-49021 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49021, GHSA-44h7-hpp5-qghj, UBUNTU-CVE-2022-49021.