CVE-2022-49486 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
ASoC: fsl: Fix refcount leak in imx_sgtl5000_probe
of_find_i2c_device_by_node() takes a reference, In error paths, we should call put_device() to drop the reference to aviod refount leak.
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Analysis
by VulDB Data Team • 02/26/2025
The vulnerability CVE-2022-49486 represents a reference counting issue within the Freescale SoC audio subsystem of the Linux kernel specifically affecting the imx_sgtl5000_probe function. This flaw exists in the audio driver component responsible for managing the SGTL5000 audio codec on i.MX platforms. The issue manifests as a resource management error where the kernel fails to properly release references to I2C devices during error handling paths, creating a potential for resource exhaustion and system instability.
The technical root cause stems from the improper handling of device references within the audio subsystem's probe function. When of_find_i2c_device_by_node() is invoked, it increments the reference count of the I2C device to ensure the device remains accessible during the probe operation. However, in error conditions or failure paths, the code fails to call put_device() to decrement the reference count, leading to a reference leak. This pattern violates fundamental resource management principles and creates a situation where device references accumulate without being properly released, ultimately consuming kernel memory resources and potentially leading to system resource exhaustion.
From an operational impact perspective, this vulnerability affects systems running Linux kernels with the Freescale i.MX audio subsystem, particularly embedded devices and automotive systems that rely on the SGTL5000 codec for audio functionality. The reference leak may not immediately cause system crashes but can lead to gradual resource degradation over time, potentially resulting in system instability, audio subsystem failures, or complete system hangs. The vulnerability is classified as a resource leak under CWE-404, specifically related to improper resource management in kernel space drivers. This type of flaw can be exploited by malicious actors to perform resource exhaustion attacks, particularly in embedded systems where memory resources are constrained.
The mitigation strategy involves applying the kernel patch that ensures proper reference counting by adding the missing put_device() call in error paths of the imx_sgtl5000_probe function. This fix aligns with the ATT&CK framework's defensive techniques for kernel-level exploitation prevention, specifically addressing the T1547.006 technique related to kernel module manipulation and resource management. System administrators should prioritize updating affected kernel versions, particularly those running on embedded devices, automotive platforms, and industrial control systems. The fix demonstrates proper kernel development practices and follows the Linux kernel's established patterns for reference counting in device drivers, ensuring that all device references are properly balanced regardless of execution paths. Organizations should conduct vulnerability assessments on their embedded audio systems and ensure timely kernel updates to prevent potential exploitation of this reference counting flaw.