CVE-2010-5329 in Linux
Summary
by MITRE
The video_usercopy function in drivers/media/video/v4l2-ioctl.c in the Linux kernel before 2.6.39 relies on the count value of a v4l2_ext_controls data structure to determine a kmalloc size, which might allow local users to cause a denial of service (memory consumption) via a large value.
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Analysis
by VulDB Data Team • 03/04/2025
The vulnerability described in CVE-2010-5329 represents a critical memory management flaw within the Linux kernel's video4linux2 (v4l2) subsystem that affects systems running kernel versions prior to 2.6.39. This issue resides in the video_usercopy function located in drivers/media/video/v4l2-ioctl.c, which handles user-space to kernel-space data transfers for video control operations. The vulnerability stems from improper validation of input parameters, specifically the count field within the v4l2_ext_controls data structure that is used to determine memory allocation sizes during kernel operations.
The technical flaw manifests when a local user executes a malicious ioctl call that manipulates the count parameter within the v4l2_ext_controls structure to an excessively large value. The video_usercopy function processes this count value directly without adequate bounds checking or sanitization, leading to a kmalloc call that attempts to allocate an enormous amount of kernel memory. This improper handling of user-supplied data creates a path for memory exhaustion attacks where the kernel's memory allocator is overwhelmed by requests for massive memory blocks that exceed available system resources.
The operational impact of this vulnerability extends beyond simple denial of service, as it can effectively render the affected system unstable or unresponsive by consuming all available kernel memory. Local attackers can exploit this weakness to exhaust system resources, potentially causing system crashes or making the system unavailable to legitimate users. The vulnerability is particularly concerning because it operates at the kernel level, meaning that successful exploitation can compromise the entire system integrity and availability. This type of vulnerability falls under CWE-129, which addresses improper validation of the length of input data, and can be categorized under ATT&CK technique T1499.1 for resource exhaustion attacks targeting operating systems.
Mitigation strategies for this vulnerability require immediate kernel updates to version 2.6.39 or later, where the problematic code has been patched to properly validate the count parameter before using it in memory allocation calculations. System administrators should also implement monitoring solutions to detect unusual memory allocation patterns and consider implementing kernel hardening measures such as stack canaries and memory protection mechanisms. Additionally, access controls should be strengthened to limit local user privileges that could potentially exploit such kernel-level vulnerabilities, as the attack vector requires local system access but can result in significant system compromise. The patch for this vulnerability specifically addresses the missing input validation by ensuring that the count field in v4l2_ext_controls is properly bounded before being used in kmalloc operations, preventing the allocation of excessive memory blocks that could exhaust system resources.