CVE-2019-19067 in Linux
Summary
by MITRE
Four memory leaks in the acp_hw_init() function in drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c in the Linux kernel before 5.3.8 allow attackers to cause a denial of service (memory consumption) by triggering mfd_add_hotplug_devices() or pm_genpd_add_device() failures, aka CID-57be09c6e874.
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability identified as CVE-2019-19067 represents a critical memory management flaw within the Linux kernel's AMDGPU driver component, specifically affecting systems running kernel versions prior to 5.3.8. This issue resides in the acp_hw_init() function located within drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c, where four distinct memory leaks have been discovered that can be exploited to cause significant system instability. The vulnerability stems from inadequate memory cleanup procedures during hardware initialization processes, particularly when the system attempts to add hotplug devices through mfd_add_hotplug_devices() or when power management generic power domains are configured via pm_genpd_add_device().
The technical implementation of this vulnerability involves improper memory allocation and deallocation sequences within the AMDGPU driver's audio component initialization routine. When the acp_hw_init() function encounters failures during device registration or power domain configuration, it fails to properly release previously allocated memory resources, resulting in persistent memory leaks that accumulate over time. These memory leaks directly relate to CWE-401, which classifies improper handling of memory allocation failures, and can be categorized under ATT&CK technique T1499.004 for resource exhaustion attacks. The flaw manifests when the system attempts to initialize audio components for AMDGPU hardware, particularly in configurations involving multi-device systems or when hotplug events occur during system operation.
The operational impact of CVE-2019-19067 extends beyond simple performance degradation to potentially causing complete system instability or denial of service conditions. Attackers can exploit this vulnerability by triggering repeated failures in the device initialization process, causing the system to consume increasing amounts of memory until system resources are exhausted. This memory exhaustion can lead to system crashes, application failures, or complete system lockups, particularly in embedded systems or servers where memory resources are constrained. The vulnerability is particularly concerning in production environments where continuous system uptime is critical, as the memory leaks can accumulate over time without immediate detection, making the system increasingly vulnerable to resource exhaustion attacks.
Mitigation strategies for CVE-2019-19067 primarily focus on kernel version upgrades to 5.3.8 or later, where the memory leak issues have been addressed through proper memory management procedures. System administrators should prioritize patching affected systems, particularly in enterprise environments where AMDGPU hardware is deployed. Additionally, implementing monitoring solutions to track memory consumption patterns can help detect potential exploitation attempts before they cause system instability. The fix implemented in the patched kernel versions addresses the root cause by ensuring proper error handling and memory cleanup during device initialization failures, aligning with security best practices outlined in the Linux kernel security documentation and following established protocols for preventing memory leak vulnerabilities in kernel drivers.