CVE-2024-40932 in Linux
Summary
by MITRE • 07/12/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/exynos/vidi: fix memory leak in .get_modes()
The duplicated EDID is never freed. Fix it.
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Analysis
by VulDB Data Team • 09/26/2024
The vulnerability CVE-2024-40932 represents a memory leak issue within the Linux kernel's display subsystem, specifically affecting the exynos video interface driver. This flaw exists in the drm/exynos/vidi component where the .get_modes() function fails to properly release duplicated EDID (Extended Display Identification Data) structures. The issue stems from improper memory management practices where allocated memory for EDID data is not correctly deallocated, leading to gradual memory consumption over time. Such memory leaks can occur repeatedly during display mode enumeration operations when the driver processes multiple EDID structures for different display outputs. The vulnerability manifests when the kernel attempts to retrieve display modes from connected monitors through the exynos video interface, particularly in embedded systems utilizing samsung exynos SoCs that rely on this driver for display management. This type of memory leak represents a classic pattern of resource management failure where dynamic memory allocation occurs without corresponding deallocation, creating a persistent memory footprint that can grow over time.
The technical flaw in CVE-2024-40932 can be classified as a memory leak under CWE-401, specifically categorized as an improper management of dynamic memory allocation. The root cause lies in the driver's implementation where duplicate EDID data structures are created during mode enumeration but never freed when the function returns or completes its operation. This creates a scenario where each invocation of the .get_modes() function potentially leaves behind unreferenced memory segments that cannot be reclaimed by the system's memory manager. The issue is particularly concerning in embedded systems where memory resources are limited and continuous operation is expected. The vulnerability affects the kernel's display management subsystem and can be triggered through normal display mode detection operations that occur during system boot, hotplug events, or when switching between different display configurations. The leak occurs in the context of the drm/exynos/vidi driver which handles video interface operations for exynos platform devices, making it relevant to a specific class of embedded and mobile devices that utilize samsung's exynos processor architecture.
From an operational perspective, CVE-2024-40932 can lead to significant system stability issues and resource exhaustion over extended periods of operation. While the individual memory leak may appear minor, repeated occurrences during normal system operation can accumulate to substantial memory consumption that impacts overall system performance. The vulnerability is particularly problematic in embedded systems or devices with limited memory capacity where such leaks can contribute to system instability, reduced responsiveness, or even complete system crashes under extreme conditions. The impact is exacerbated in systems that frequently perform display mode detection or handle multiple display outputs simultaneously. This memory leak can contribute to broader system degradation where the kernel's memory management becomes increasingly fragmented and less efficient over time. Additionally, the vulnerability may be exploited in resource exhaustion attacks where malicious actors could potentially trigger repeated memory leaks to degrade system performance or availability, making this a concern for both general system stability and potential security implications.
Mitigation strategies for CVE-2024-40932 should focus on implementing proper memory management practices within the affected kernel driver. The fix involves ensuring that all duplicated EDID structures created during .get_modes() execution are properly freed when they are no longer needed. System administrators should prioritize applying kernel updates that include the patched version of the drm/exynos/vidi driver to address the memory leak. Organizations using embedded systems or devices based on exynos processors should monitor their kernel versions and apply security patches promptly to prevent accumulation of memory leaks. The fix aligns with standard memory management best practices outlined in various security frameworks including the ATT&CK framework's system hardening categories, where proper resource management and memory deallocation are fundamental defensive measures. Regular system monitoring should include tracking memory usage patterns to identify potential memory leak accumulation, and system administrators should implement routine maintenance procedures that include kernel updates and security patch management to prevent exploitation of such vulnerabilities. The vulnerability serves as a reminder of the critical importance of proper resource management in kernel space code and the potential for seemingly minor memory management flaws to create significant system stability issues over time.