CVE-2024-36959 in Linux
Summary
by MITRE • 05/30/2024
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: devicetree: fix refcount leak in pinctrl_dt_to_map()
If we fail to allocate propname buffer, we need to drop the reference count we just took. Because the pinctrl_dt_free_maps() includes the droping operation, here we call it directly.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 10/29/2024
The vulnerability identified as CVE-2024-36959 represents a memory management issue within the Linux kernel's pinctrl subsystem, specifically affecting the device tree parsing functionality. This flaw manifests in the pinctrl_dt_to_map() function where improper reference counting handling leads to resource leakage. The pinctrl subsystem is responsible for managing pin configurations and multiplexing in embedded systems, making it a critical component for hardware abstraction and device management. When device tree nodes are processed to map pin configurations, the kernel must maintain proper reference counts to ensure memory is correctly managed throughout the allocation and deallocation cycles.
The technical flaw occurs when the function attempts to allocate a property name buffer but fails during this allocation process. In such failure scenarios, the kernel code incorrectly fails to decrement the reference count that was previously incremented when acquiring the resource. This reference count leak represents a classic memory management vulnerability where allocated resources remain in use even though the allocation has failed. The issue is particularly concerning because it operates within the kernel's device tree parsing mechanism, which is invoked frequently during system boot and device initialization processes, potentially leading to gradual memory exhaustion over time.
The operational impact of this vulnerability extends beyond simple memory leakage, as it can contribute to system instability and performance degradation. When reference count leaks accumulate over time, they can lead to memory pressure conditions that affect the overall system responsiveness and potentially cause system crashes or hangs. The vulnerability affects systems that rely heavily on device tree parsing for pin configuration management, which includes a wide range of embedded devices, single-board computers, and mobile platforms. The issue is particularly relevant in resource-constrained environments where memory management efficiency is critical for system operation and reliability.
The fix implemented for CVE-2024-36959 addresses the root cause by ensuring that when buffer allocation fails, the appropriate cleanup mechanism is invoked immediately. The solution leverages the existing pinctrl_dt_free_maps() function which already contains the necessary reference count dropping operations, thereby eliminating the need for duplicate cleanup logic. This approach follows established kernel programming practices for resource management and error handling, ensuring that all acquired resources are properly released regardless of the execution path taken. The fix demonstrates proper adherence to the principle of resource acquisition is initialization where resources are properly managed through their entire lifecycle. This vulnerability aligns with CWE-404, which categorizes improper resource release or cleanup as a common software weakness, and may map to ATT&CK technique T1490 for resource exhaustion attacks that could be leveraged through memory leaks. The resolution ensures that the kernel maintains proper reference counting semantics and prevents potential denial of service conditions that could arise from uncontrolled memory consumption.