CVE-2024-43906 in Linux
Summary
by MITRE • 08/26/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/admgpu: fix dereferencing null pointer context
When user space sets an invalid ta type, the pointer context will be empty. So it need to check the pointer context before using it
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 12/13/2024
The vulnerability identified as CVE-2024-43906 represents a critical null pointer dereference issue within the Linux kernel's display subsystem, specifically affecting the amdgpu driver component. This flaw exists in the direct rendering manager framework that handles graphics processing unit operations for AMD hardware. The vulnerability stems from inadequate input validation when user space applications attempt to configure certain trusted application types within the graphics driver context. When an invalid trusted application type is specified by user space, the driver fails to properly initialize or validate the context pointer, resulting in a scenario where subsequent operations attempt to dereference a null pointer reference. This represents a fundamental failure in defensive programming practices that violates core security principles for kernel space operations.
The technical implementation of this vulnerability occurs within the drm/admgpu subsystem where the driver processes requests from user space applications to configure trusted application contexts. The flaw manifests when user space applications provide invalid or malformed ta type parameters during graphics context initialization or configuration operations. The driver code does not perform proper null pointer validation before attempting to access the context structure, leading to immediate kernel panic or system crash when the invalid parameter is processed. This type of vulnerability falls under CWE-476 which specifically addresses null pointer dereference conditions in software implementations. The flaw demonstrates poor input validation and error handling mechanisms that should have been implemented to prevent such dangerous operations in kernel space.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable privilege escalation or denial of service attacks against systems running affected kernel versions. An attacker could exploit this vulnerability by crafting malicious user space applications that deliberately set invalid ta types, thereby triggering the null pointer dereference condition. This could result in complete system crashes, requiring manual reboot to restore normal operation, or in more sophisticated attack scenarios could potentially be leveraged to gain elevated privileges within the kernel space. The vulnerability affects systems utilizing AMD graphics hardware through the amdgpu driver, which is widely deployed across various Linux distributions and embedded systems. This makes the impact particularly concerning given the broad adoption of AMD graphics solutions in both enterprise and consumer environments.
Mitigation strategies for CVE-2024-43906 should prioritize immediate kernel updates from vendors that include the patched version of the amdgpu driver. System administrators should ensure all affected systems receive the latest security patches that implement proper null pointer validation before any context pointer is accessed. The fix typically involves adding a simple validation check that verifies the pointer context is not null before proceeding with any operations on the structure. Additional defensive measures include implementing proper input sanitization at the user space level to prevent malformed parameters from reaching the kernel driver, monitoring system logs for potential exploitation attempts, and maintaining comprehensive system integrity checks. From an ATT&CK framework perspective, this vulnerability could be categorized under privilege escalation techniques and system resource hijacking, as it enables attackers to disrupt normal system operations and potentially gain unauthorized access to kernel resources. Organizations should also consider implementing kernel module hardening measures and monitoring for unusual kernel panic events that might indicate exploitation attempts.