CVE-2022-48860 in Linux
Summary
by MITRE • 07/16/2024
In the Linux kernel, the following vulnerability has been resolved:
ethernet: Fix error handling in xemaclite_of_probe
This node pointer is returned by of_parse_phandle() with refcount incremented in this function. Calling of_node_put() to avoid the refcount leak. As the remove function do.
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Analysis
by VulDB Data Team • 07/23/2024
The vulnerability CVE-2022-48860 represents a memory management issue within the Linux kernel's ethernet driver subsystem, specifically affecting the xemaclite_of_probe function. This flaw manifests as a reference count leak that occurs during device tree node processing in the ethernet driver initialization sequence. The vulnerability arises from improper handling of device tree node references when the ethernet driver attempts to parse and process device tree properties for hardware configuration.
The technical root cause involves the of_parse_phandle() function which is responsible for parsing device tree phandles and automatically increments the reference count of the returned node pointer to maintain proper memory management. However, in the xemaclite_of_probe function, the code fails to properly decrement this reference count through the standard of_node_put() function call. This creates a situation where the device tree node reference remains allocated in memory even after the driver initialization process should have completed, leading to a gradual accumulation of unreleased memory resources.
This memory leak vulnerability falls under the CWE-401 category of "Improper Release of Memory Before Removing Last Reference" and represents a classic resource management error that can lead to system instability and performance degradation over time. The issue is particularly concerning in embedded systems and network infrastructure devices where the Linux kernel runs continuously and memory resources are constrained. The vulnerability is classified under the ATT&CK technique T1490 "Inhibit System Recovery" as memory leaks can eventually lead to system resource exhaustion and potential denial of service conditions.
The operational impact of this vulnerability extends beyond simple memory consumption issues. While the immediate effect may appear benign, the cumulative nature of reference count leaks can result in progressive system degradation, particularly in systems with frequent device initialization and removal cycles. In production environments running multiple ethernet devices or in high-availability systems, this leak can contribute to memory pressure that affects overall system performance and reliability. The vulnerability affects systems using the xemaclite ethernet driver implementation, which is commonly found in various embedded systems and hardware platforms that utilize device tree configuration for hardware description.
Mitigation strategies for this vulnerability require updating the affected Linux kernel versions to patches that properly implement the of_node_put() function call after processing device tree node references. System administrators should prioritize kernel updates, particularly for embedded systems and network infrastructure devices where the xemaclite driver is in use. The fix involves adding the appropriate reference count decrement operation in the error handling path of the xemaclite_of_probe function, ensuring that all node pointers returned by of_parse_phandle() are properly released regardless of the execution path taken during driver initialization. Additionally, monitoring system memory usage and implementing automated alerting for memory consumption patterns can help detect potential exploitation of this vulnerability in production environments.