CVE-2022-48772

What it actually does

Null pointer dereference in lgdt3306a_probe when client platform_data is absent, resulting in KASAN-detected invalid read during kmemdup in the Linux kernel media driver.

Why it matters to the business

Kernel crashes or denial of service on systems initializing the lgdt3306a hardware, potentially disrupting media capture or device bring-up in affected Linux deployments; low prevalence reduces overall exposure.

How an attack unfolds

An attacker supplies or registers an I2C client lacking platform_data to the lgdt3306a driver; during i2c_device_probe the missing check leads directly to null dereference inside kmemdup, crashing the kernel. No named threat actors are associated with exploitation.

How to fix it

Apply the upstream kernel fix adding the platform_data null check; for mailcow/mailcow-dockerized update to commit 36b5cccd186090d726de62b6b00d1e842e67aacd.

How to confirm the fix worked

Confirm the source contains an explicit platform_data validity test before kmemdup in lgdt3306a_probe and that the driver initializes without null dereference under the same conditions.

Typical attack path

1. Locate or configure a system exposing the lgdt3306a I2C driver
2. Register a client device without valid platform_data
3. Trigger device probe via i2c_device_probe
4. Execute kmemdup on null pointer causing kernel fault

How to detect it

Search kernel logs for KASAN null-ptr-deref reports referencing kmemdup and lgdt3306a_probe or i2c_device_probe call traces.

• BUG: KASAN: null-ptr-deref in kmemdup
• lgdt3306a_probe+0x52/0x310
• Read of size 40 at addr 0000000000000000
• i2c_device_probe

What your security team should do

• Patch affected kernels or containers to the listed fixed commit
• Audit I2C device trees and probe paths for missing platform_data
• Enable KASAN or similar kernel sanitizers in test environments to surface similar issues