CVE-2012-2384 in Linux
Summary
by MITRE
Integer overflow in the i915_gem_do_execbuffer function in drivers/gpu/drm/i915/i915_gem_execbuffer.c in the Direct Rendering Manager (DRM) subsystem in the Linux kernel before 3.3.5 on 32-bit platforms allows local users to cause a denial of service (out-of-bounds write) or possibly have unspecified other impact via a crafted ioctl call.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/03/2021
The vulnerability identified as CVE-2012-2384 represents a critical integer overflow flaw within the Linux kernel's Direct Rendering Manager subsystem, specifically affecting 32-bit platforms. This issue resides in the i915_gem_do_execbuffer function located in drivers/gpu/drm/i915/i915_gem_execbuffer.c, which handles graphics command buffer execution for Intel graphics hardware. The flaw manifests when processing crafted ioctl calls that manipulate the graphics execution buffer parameters, creating conditions where integer arithmetic operations exceed their maximum representable values.
The technical implementation of this vulnerability stems from inadequate input validation and overflow checking within the graphics command buffer processing logic. When a local user submits a specially crafted ioctl request, the function fails to properly validate the size parameters of graphics command buffers, leading to a scenario where integer overflow occurs during buffer size calculations. This overflow results in a subsequent out-of-bounds write operation that can corrupt kernel memory structures, potentially leading to system instability or complete denial of service conditions. The vulnerability's impact extends beyond simple denial of service as it may enable arbitrary code execution under certain conditions, making it particularly dangerous for systems with graphics-intensive workloads.
From an operational perspective, this vulnerability affects all Linux systems running kernel versions prior to 3.3.5 on 32-bit architectures, including desktops, servers, and embedded systems utilizing Intel graphics hardware. The local privilege escalation aspect means that any user with access to the system can potentially exploit this vulnerability without requiring elevated privileges. The attack vector through ioctl calls makes it particularly insidious as it can be triggered through standard graphics application interfaces, making detection and prevention challenging. The vulnerability directly maps to CWE-190, Integer Overflow or Wraparound, and aligns with ATT&CK technique T1059.003 for executing commands through the graphics subsystem. Systems utilizing Intel graphics drivers such as i915 are particularly vulnerable, with the issue affecting various Intel GPU generations including those in the 2nd and 3rd generation Core processors.
Mitigation strategies for CVE-2012-2384 primarily focus on kernel version updates, with the most effective solution being the upgrade to Linux kernel 3.3.5 or later, which includes proper integer overflow protections. System administrators should also implement kernel lockdown mechanisms and restrict user access to graphics ioctl interfaces where possible. Additional defensive measures include monitoring for unusual graphics command buffer operations and implementing runtime integrity checks for graphics subsystem components. The vulnerability demonstrates the importance of proper input validation in kernel space operations and highlights the need for comprehensive security testing of graphics drivers, particularly those handling user-supplied data through ioctl interfaces. Organizations should also consider implementing network segmentation to limit exposure and ensure that graphics-intensive applications are properly sandboxed to minimize potential exploitation impact.