CVE-2022-49813 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
net: ena: Fix error handling in ena_init()
The ena_init() won't destroy workqueue created by create_singlethread_workqueue() when pci_register_driver() failed. Call destroy_workqueue() when pci_register_driver() failed to prevent the resource leak.
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Analysis
by VulDB Data Team • 11/07/2025
The vulnerability identified as CVE-2022-49813 represents a resource management flaw within the Linux kernel's Elastic Network Adapter (ENA) driver implementation. This issue specifically affects the ena_init() function which is responsible for initializing the network adapter driver components. The flaw occurs during the driver registration process where the system attempts to register the PCI driver using pci_register_driver() function. When this registration fails, the driver initialization process does not properly clean up all allocated resources, creating a persistent resource leak that can accumulate over time and potentially impact system stability.
The technical root cause of this vulnerability lies in the improper error handling within the driver initialization sequence. The ENA driver utilizes create_singlethread_workqueue() to establish a workqueue for handling asynchronous network operations, which is a standard practice for managing kernel threads in network driver contexts. However, when pci_register_driver() encounters an error during driver registration, the subsequent cleanup logic fails to invoke destroy_workqueue() to properly dispose of the workqueue that was previously allocated. This creates a memory leak where the workqueue resources remain allocated even though the driver initialization has failed, violating fundamental resource management principles that are essential for maintaining system integrity.
This vulnerability operates at the kernel level and specifically impacts systems utilizing Elastic Network Adapter hardware, which is commonly found in Amazon EC2 instances and other cloud computing environments. The operational impact of this resource leak manifests as gradual memory consumption increases within the kernel space, potentially leading to system performance degradation, reduced available memory for other processes, and in severe cases, system instability or crashes. The issue is particularly concerning in high-availability environments where continuous driver operations are expected, as the accumulation of leaked resources can compound over time and create unpredictable system behavior.
From a cybersecurity perspective, this vulnerability aligns with CWE-404, which addresses improper resource cleanup or release, and can be categorized under ATT&CK technique T1547.001 for system service modification and T1068 for exploit for privilege escalation. The resource leak could potentially be exploited by malicious actors to consume system resources progressively, leading to denial of service conditions. The fix implemented addresses this by ensuring that when pci_register_driver() fails, the corresponding destroy_workqueue() call is executed to properly release the allocated workqueue resources, thereby preventing the accumulation of leaked memory and maintaining proper resource accounting within the kernel's memory management subsystem.
The mitigation strategy for this vulnerability involves applying the appropriate kernel security updates that contain the patched ena_init() function with corrected error handling logic. System administrators should prioritize patching affected systems, particularly in production environments where continuous operation and resource efficiency are critical. Additionally, monitoring systems for unusual memory consumption patterns or resource leaks can help identify potential exploitation attempts. The fix demonstrates proper defensive programming practices by ensuring that all allocated resources are properly released regardless of the execution path taken during initialization, which aligns with the principle of resource acquisition is initialization and proper error handling in kernel space operations.