CVE-2022-49384 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
md: fix double free of io_acct_set bioset
Now io_acct_set is alloc and free in personality. Remove the codes that free io_acct_set in md_free and md_stop.
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Analysis
by VulDB Data Team • 02/26/2025
The vulnerability identified as CVE-2022-49384 represents a critical double free error within the Linux kernel's md (multiple device) subsystem, specifically affecting the management of io_acct_set bioset structures. This issue occurs in the context of software RAID implementations where the md driver handles multiple storage devices to create redundant storage arrays. The flaw manifests when the kernel attempts to free the same memory allocation twice, which can lead to unpredictable behavior and potential system instability. The vulnerability is particularly concerning because it affects the core storage management functionality of Linux systems, potentially compromising data integrity and system reliability.
The technical root cause of this vulnerability stems from improper memory management within the md driver's cleanup routines. The io_acct_set bioset structure, which tracks I/O accounting information for the md subsystem, is being allocated in the personality layer but is being freed in multiple locations throughout the md driver's lifecycle. Specifically, the md_free and md_stop functions contain code that attempts to free the same io_acct_set bioset structure that was already freed elsewhere in the personality layer. This violates fundamental memory management principles and creates a classic double free vulnerability pattern that can be exploited to corrupt kernel memory structures.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling privilege escalation and denial of service conditions within Linux environments. When the double free occurs, it can corrupt the kernel's memory allocator's internal data structures, leading to memory corruption that attackers might leverage to execute arbitrary code with kernel privileges. This represents a significant security risk for systems running Linux kernels that incorporate the md subsystem, particularly in enterprise environments where RAID configurations are commonly used for data redundancy and performance. The vulnerability affects systems where multiple device drivers are actively managing storage arrays, making it particularly relevant for servers, storage appliances, and high-performance computing environments.
This vulnerability aligns with CWE-415, which specifically addresses double free conditions in memory management, and demonstrates the critical importance of proper resource cleanup in kernel space operations. The remediation approach taken by the Linux kernel developers involves removing the redundant free operations from the md_free and md_stop functions, ensuring that the io_acct_set bioset is freed exactly once by the personality layer. This fix follows established best practices for kernel memory management and aligns with ATT&CK technique T1068, which covers the exploitation of local privilege escalation vulnerabilities. Organizations should prioritize applying this kernel update to mitigate the risk of exploitation, particularly in environments where the md subsystem is actively utilized for storage management. The fix represents a straightforward but critical correction to prevent memory corruption that could otherwise lead to system compromise or data loss.