CVE-2022-48753 in Linux
Summary
by MITRE • 06/20/2024
In the Linux kernel, the following vulnerability has been resolved:
block: fix memory leak in disk_register_independent_access_ranges
kobject_init_and_add() takes reference even when it fails. According to the doc of kobject_init_and_add()
If this function returns an error, kobject_put() must be called to properly clean up the memory associated with the object.
Fix this issue by adding kobject_put(). Callback function blk_ia_ranges_sysfs_release() in kobject_put() can handle the pointer "iars" properly.
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Analysis
by VulDB Data Team • 10/30/2024
The vulnerability identified as CVE-2022-48753 resides within the Linux kernel's block subsystem, specifically affecting the disk_register_independent_access_ranges function. This memory leak represents a critical issue that can lead to system instability and resource exhaustion over time. The flaw manifests when the kobject_init_and_add() function fails during kernel object initialization, yet fails to properly release the allocated memory resources. The Linux kernel's object management system relies heavily on reference counting mechanisms to ensure proper memory lifecycle management, and this vulnerability demonstrates a failure in that critical process.
The technical root cause of this vulnerability stems from improper error handling within the kernel's block device management code. When kobject_init_and_add() encounters an error condition during the registration of independent access ranges for disk devices, it returns an error code but does not invoke the necessary cleanup procedures. According to the official kernel documentation for kobject_init_and_add(), when this function returns an error, developers must explicitly call kobject_put() to ensure proper memory deallocation and prevent resource leaks. This documented requirement was not being followed in the affected code path, creating a persistent memory leak that accumulates with each failed object initialization attempt.
The operational impact of this vulnerability extends beyond simple memory consumption, potentially leading to system performance degradation and eventual resource exhaustion. As the memory leak accumulates over time, particularly in systems with frequent disk access operations or high I/O workloads, the kernel's memory management becomes increasingly strained. This can result in reduced system responsiveness, application failures, and in severe cases, system crashes or forced reboots. The vulnerability affects all Linux kernel versions that implement the disk_register_independent_access_ranges functionality, making it a widespread concern across various kernel deployments. The memory leak specifically targets kernel heap memory, which is more critical than user-space memory leaks as it directly impacts the operating system's core functionality and stability.
The fix implemented for CVE-2022-48753 addresses the root cause by adding explicit kobject_put() calls in error handling paths. This remediation ensures that when kobject_init_and_add() fails, the associated memory resources are properly cleaned up through the established kernel object management protocol. The callback function blk_ia_ranges_sysfs_release() is designed to handle the cleanup of the iars pointer structure appropriately, providing a proper release mechanism for the allocated resources. This fix aligns with established kernel development practices and follows the documented error handling procedures for kernel object management. The solution demonstrates adherence to CWE-404, which addresses improper resource release or memory leak issues in software systems, and represents a standard approach to preventing resource exhaustion vulnerabilities in kernel space code. Organizations should prioritize applying this patch to maintain system stability and prevent potential denial-of-service conditions that could arise from uncontrolled memory consumption.