CVE-2024-50068 in Linux
Summary
by MITRE • 10/29/2024
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/tests/sysfs-kunit.h: fix memory leak in damon_sysfs_test_add_targets()
The sysfs_target->regions allocated in damon_sysfs_regions_alloc() is not freed in damon_sysfs_test_add_targets(), which cause the following memory leak, free it to fix it.
unreferenced object 0xffffff80c2a8db80 (size 96): comm "kunit_try_catch", pid 187, jiffies 4294894363 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 0): [] kmemleak_alloc+0x34/0x40
[] __kmalloc_cache_noprof+0x26c/0x2f4
[] damon_sysfs_test_add_targets+0x1cc/0x738
[] kunit_try_run_case+0x13c/0x3ac
[] kunit_generic_run_threadfn_adapter+0x80/0xec
[] kthread+0x2e8/0x374
[] ret_from_fork+0x10/0x20
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/02/2025
The vulnerability identified as CVE-2024-50068 represents a memory leak within the Linux kernel's DAMON (Dynamic Address Monitoring) subsystem, specifically within the sysfs interface implementation. This issue occurs in the damon_sysfs_test_add_targets() function where allocated memory for sysfs_target->regions is not properly freed, creating a persistent memory leak that can accumulate over time and potentially impact system stability and performance. The DAMON subsystem is designed for monitoring memory access patterns and is commonly used for memory management optimization and security analysis. The memory leak manifests when the damon_sysfs_regions_alloc() function allocates memory for region tracking structures but fails to release this memory in the test function, creating unreferenced objects that remain in kernel memory. This type of memory management error falls under the category of improper deallocation as defined by CWE-415, which specifically addresses the issue of freeing memory twice or failing to free allocated memory. The vulnerability is particularly concerning because it occurs within kernel space testing infrastructure, meaning it could potentially be exploited to consume system resources or create instability during kernel testing phases.
The technical flaw stems from a missing memory cleanup operation within the kernel's testing framework for DAMON functionality. When damon_sysfs_test_add_targets() executes, it calls damon_sysfs_regions_alloc() to allocate memory structures for tracking memory regions, but the subsequent deallocation step is omitted. This creates a scenario where each invocation of the test function results in a memory leak of 96 bytes, as indicated by the memory dump showing the unreferenced object size. The backtrace analysis reveals the execution path leading to the leak, showing the allocation occurring within kmemleak_alloc and the specific function damon_sysfs_test_add_targets being the source of the problem. The kunit_try_catch framework, which is used for kernel unit testing, executes this function during test cases, making the memory leak potentially recurring during normal kernel testing operations. The issue is particularly relevant in environments where kernel testing is frequent or automated, as the accumulation of these small memory leaks can lead to significant memory consumption over time.
The operational impact of this memory leak extends beyond simple resource consumption, potentially affecting system performance and stability in production environments. While the leak occurs in a test function context, the implications are significant because kernel testing infrastructure is often part of continuous integration and deployment pipelines, meaning the leak could accumulate during regular system maintenance or development cycles. The 96-byte leak per function invocation, though seemingly small, can compound over time and potentially lead to memory pressure conditions that affect other kernel subsystems. The vulnerability is particularly concerning in security-sensitive environments where kernel memory management is critical, as memory leaks can create potential attack vectors or reduce system resilience. The leak could also mask other memory-related issues during kernel debugging and testing, making it more difficult to identify genuine problems within the system. This aligns with ATT&CK technique T1070.004 which addresses the use of memory dumps and kernel memory analysis for reconnaissance and exploitation purposes.
Mitigation strategies for this vulnerability focus on implementing proper memory management practices within the kernel codebase. The immediate solution requires modifying the damon_sysfs_test_add_targets() function to include the missing deallocation call for sysfs_target->regions that was allocated by damon_sysfs_regions_alloc(). This fix should follow established kernel memory management practices and ensure that all allocated resources are properly freed in all execution paths. System administrators should ensure that kernel updates containing this fix are applied promptly, particularly in environments where kernel testing is frequent or automated. Monitoring for memory leaks in kernel testing environments should be enhanced to detect similar issues in other subsystems, as this vulnerability demonstrates the importance of thorough memory management in kernel code. The fix should also be validated through comprehensive kernel testing to ensure that no regressions are introduced, and that the memory management patterns align with the kernel's memory allocation frameworks. Additionally, developers should conduct code reviews focusing on memory allocation and deallocation patterns to prevent similar issues from being introduced in future kernel modifications.