CVE-2012-0044 in Linux
Summary
by MITRE • 01/25/2023
Integer overflow in the drm_mode_dirtyfb_ioctl function in drivers/gpu/drm/drm_crtc.c in the Direct Rendering Manager (DRM) subsystem in the Linux kernel before 3.1.5 allows local users to gain privileges or cause a denial of service (memory corruption) via a crafted ioctl call.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2012-0044 represents a critical integer overflow flaw within the Direct Rendering Manager subsystem of the Linux kernel, specifically affecting the drm_mode_dirtyfb_ioctl function located in drivers/gpu/drm/drm_crtc.c. This issue exists in kernel versions prior to 3.1.5 and demonstrates how seemingly benign ioctl operations can be exploited to achieve privilege escalation or system instability. The vulnerability stems from improper input validation and arithmetic handling within the graphics subsystem, which is responsible for managing display hardware resources and coordinating graphics operations between user space and kernel space.
The technical exploitation of this vulnerability occurs when a local user crafts a malicious ioctl call that triggers an integer overflow condition during the processing of framebuffer dirty rectangle information. When the drm_mode_dirtyfb_ioctl function processes the user-supplied parameters, it fails to properly validate the size calculations or bounds checking for the dirty rectangle coordinates, leading to a situation where arithmetic operations produce values that exceed the maximum representable integer limits. This overflow condition results in memory corruption that can be leveraged to manipulate kernel memory structures, potentially allowing attackers to execute arbitrary code with kernel privileges or cause system crashes through memory corruption.
From an operational perspective, this vulnerability presents significant security implications for systems running affected kernel versions, particularly those with graphics-intensive applications or multi-user environments where local privilege escalation could lead to complete system compromise. The attack vector is relatively straightforward as it requires only local access to the system, making it accessible to users with basic system permissions. The potential impact includes both privilege escalation and denial of service scenarios, with the former allowing attackers to elevate their privileges to root level and the latter potentially causing system instability or complete system crashes. This vulnerability directly maps to CWE-190, which identifies integer overflow conditions, and aligns with ATT&CK technique T1068, which covers privilege escalation through local exploits.
Mitigation strategies for CVE-2012-0044 primarily focus on kernel version updates to 3.1.5 or later, which contain the necessary patches to address the integer overflow condition in the drm_mode_dirtyfb_ioctl function. System administrators should prioritize patching affected systems, particularly those running graphics-intensive workloads or serving multiple users. Additional protective measures include implementing proper input validation mechanisms, employing kernel hardening techniques such as stack canaries and address space layout randomization, and monitoring for suspicious ioctl activity patterns. Organizations should also consider restricting local user access to graphics subsystem interfaces where possible and implementing least privilege principles to minimize potential exploitation impact. The vulnerability underscores the importance of proper integer arithmetic handling in kernel space operations and demonstrates how graphics subsystems can serve as attack vectors for privilege escalation attacks.