CVE-2017-5576 in Linux
Summary
by MITRE
Integer overflow in the vc4_get_bcl function in drivers/gpu/drm/vc4/vc4_gem.c in the VideoCore DRM driver in the Linux kernel before 4.9.7 allows local users to cause a denial of service or possibly have unspecified other impact via a crafted size value in a VC4_SUBMIT_CL ioctl call.
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Analysis
by VulDB Data Team • 11/11/2022
The vulnerability identified as CVE-2017-5576 represents a critical integer overflow flaw within the VideoCore DRM driver component of the Linux kernel. This issue specifically affects the vc4_get_bcl function located in drivers/gpu/drm/vc4/vc4_gem.c and impacts kernel versions prior to 4.9.7. The vulnerability arises from insufficient input validation during the processing of graphics command submission operations, creating a potential pathway for malicious exploitation that could compromise system stability and security.
The technical implementation of this vulnerability stems from an integer overflow condition that occurs when processing size parameters within the VC4_SUBMIT_CL ioctl call mechanism. When a local user crafts a malicious size value and submits it through the graphics command interface, the kernel's vc4_get_bcl function fails to properly validate or sanitize this input before performing arithmetic operations. This overflow condition can cause the system to allocate insufficient memory resources or trigger unexpected behavior in the graphics processing subsystem, ultimately leading to system instability.
From an operational perspective, this vulnerability presents significant risks to system availability and potentially confidentiality. Local users can leverage this flaw to induce denial of service conditions that may crash the graphics subsystem or cause the entire system to become unresponsive. The unspecified nature of potential additional impacts suggests that under certain conditions, this vulnerability could potentially be exploited to escalate privileges or access sensitive system resources, though this remains speculative without further evidence of exploitation vectors. The impact is particularly concerning in embedded systems or devices where graphics processing is critical to overall system operation.
The vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and demonstrates characteristics consistent with the ATT&CK technique T1068, which involves exploiting legitimate credentials to gain access to privileged functions. The flaw represents a classic case of inadequate input validation in kernel space code, where user-supplied parameters are not properly bounded or checked before being used in memory allocation or arithmetic operations. Organizations should prioritize immediate patching of affected kernel versions to address this vulnerability and prevent potential exploitation by malicious actors.
Mitigation strategies should include applying the kernel patch released in version 4.9.7 which addresses the integer overflow condition through proper input validation and size parameter checking. System administrators should also implement monitoring solutions to detect unusual graphics command submission patterns that might indicate exploitation attempts. Additionally, maintaining up-to-date kernel versions and implementing proper access controls to limit local user privileges can reduce the attack surface. The vulnerability underscores the importance of rigorous input validation in kernel space drivers and highlights the need for comprehensive security testing of graphics subsystems to prevent similar issues in the future.