CVE-2024-42139 in Linux
Summary
by MITRE • 07/30/2024
In the Linux kernel, the following vulnerability has been resolved:
ice: Fix improper extts handling
Extts events are disabled and enabled by the application ts2phc. However, in case where the driver is removed when the application is running, a specific extts event remains enabled and can cause a kernel crash. As a side effect, when the driver is reloaded and application is started again, remaining extts event for the channel from a previous run will keep firing and the message "extts on unexpected channel" might be printed to the user.
To avoid that, extts events shall be disabled when PTP is released.
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Analysis
by VulDB Data Team • 07/19/2025
The vulnerability identified as CVE-2024-42139 affects the Linux kernel's handling of external time stamping (extts) operations within the ice network driver component. This issue specifically manifests in the context of Precision Time Protocol (PTP) implementations where the ice driver manages hardware time stamping capabilities for network traffic. The flaw occurs when applications interact with the ts2phc utility to control extts events, creating a scenario where proper cleanup of time stamping resources fails during driver removal operations. The vulnerability represents a classic resource management issue that can lead to both system instability and operational disruptions in time-sensitive network applications.
The technical flaw stems from improper cleanup procedures during driver lifecycle management within the ice network driver implementation. When a PTP application utilizing extts events is running and the driver is subsequently removed, the system fails to properly disable extts events that were active during the application's operation. This results in orphaned time stamping operations that continue to trigger events even after the driver has been unloaded. The kernel crash occurs because these lingering extts events attempt to access freed or invalid memory structures, leading to memory corruption and system instability. The vulnerability is classified under CWE-459 as "Inadequate Cleanup" and represents a failure in proper resource deallocation during system shutdown or driver reload scenarios.
The operational impact of this vulnerability extends beyond simple system crashes to encompass service disruption and data integrity concerns in time-critical applications. When the driver is reloaded and the application restarted, the residual extts events from the previous session continue to fire, generating misleading "extts on unexpected channel" messages that confuse system administrators and application developers. This behavior can lead to false positive alerts, incorrect time synchronization data, and potential denial of service conditions in network infrastructure that relies on precise timing. The vulnerability particularly affects industrial network applications, telecommunications equipment, and any system where accurate time stamping is essential for network operations and protocol compliance. Attackers could potentially exploit this vulnerability to cause persistent service degradation or to disrupt time-sensitive network operations through controlled driver removal and reload cycles.
Mitigation strategies for CVE-2024-42139 involve implementing proper resource cleanup procedures during driver release operations, ensuring that all extts events are explicitly disabled before the PTP subsystem is released. System administrators should apply the latest kernel updates that contain the patched ice driver implementation, which correctly handles extts event cleanup during driver removal. Additionally, monitoring systems should be configured to detect and alert on "extts on unexpected channel" messages as potential indicators of resource leaks. The fix aligns with ATT&CK technique T1490 for "Inhibit System Recovery" by preventing the kernel from maintaining invalid state information after driver unloading. Organizations should also implement proper driver lifecycle management protocols, including graceful shutdown procedures for PTP applications and regular kernel patching schedules to maintain system security and stability. The vulnerability demonstrates the critical importance of proper resource management in kernel drivers and highlights the need for comprehensive testing of driver removal and reload scenarios to prevent similar issues in other network driver implementations.