CVE-2024-43909 in Linux
Summary
by MITRE • 08/26/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/pm: Fix the null pointer dereference for smu7
optimize the code to avoid pass a null pointer (hwmgr->backend) to function smu7_update_edc_leakage_table.
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Analysis
by VulDB Data Team • 10/13/2024
The vulnerability identified as CVE-2024-43909 represents a critical null pointer dereference issue within the Linux kernel's amdgpu display driver subsystem specifically affecting the smu7 power management component. This flaw resides in the drm/amdgpu/pm module where the kernel's graphics power management functionality interacts with AMD GPU hardware through the smu7 (System Management Unit version 7) interface. The vulnerability occurs when the system attempts to pass a null pointer reference to the smu7_update_edc_leakage_table function, which is part of the hardware management backend operations.
The technical root cause of this vulnerability stems from inadequate pointer validation within the power management code path. When the hwmgr->backend pointer fails to be properly initialized or becomes null during runtime operations, the system continues to attempt function calls using this invalid reference. This type of error falls under the CWE-476 category of Null Pointer Dereference, which represents a fundamental programming error where code assumes a pointer will always contain a valid address without proper validation checks. The specific function smu7_update_edc_leakage_table expects a valid backend pointer to operate correctly, but when this pointer is null, the kernel will crash with a segmentation fault or similar memory access violation.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise system stability and availability in environments running Linux kernels with AMD GPU support. When triggered, the null pointer dereference causes the kernel to panic and terminate the graphics subsystem, which may result in complete system lockup or forced reboot. This issue is particularly concerning in server environments or embedded systems where continuous operation is critical, as the power management subsystem failure could prevent proper GPU resource handling and thermal regulation. The vulnerability affects systems using AMD GPU hardware that rely on the smu7 power management interface, making it relevant to a wide range of desktop, workstation, and server configurations.
The mitigation for this vulnerability requires kernel-level patches that implement proper null pointer validation before passing the hwmgr->backend pointer to the smu7_update_edc_leakage_table function. Security teams should prioritize applying the official kernel updates from the Linux kernel security team that contain the specific fix for this null pointer dereference issue. Organizations running affected systems should conduct thorough testing of kernel updates in non-production environments before deployment to ensure compatibility with existing hardware configurations. Additionally, monitoring systems should be configured to detect kernel panic events or system instability patterns that may indicate exploitation attempts. The fix aligns with ATT&CK technique T1059.001 for command and script interpreter usage, as the vulnerability could potentially be exploited through kernel-level manipulation, though the primary concern remains system stability rather than direct remote code execution. System administrators should also consider implementing hardware monitoring solutions that can detect unusual power management behavior as an early warning indicator of potential exploitation attempts.