CVE-2022-49021 Information

Nov 01, 2024 cve

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: 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().

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5

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