CVE-2019-16229 in Linux
Summary
by MITRE
drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c in the Linux kernel 5.2.14 does not check the alloc_workqueue return value, leading to a NULL pointer dereference. NOTE: The security community disputes this issues as not being serious enough to be deserving a CVE id
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Analysis
by VulDB Data Team • 08/05/2024
The vulnerability identified as CVE-2019-16229 resides within the AMD Kernel Mode Driver Framework component of the Linux kernel version 5.2.14 specifically in the file drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c. This issue represents a classic null pointer dereference vulnerability that occurs when the kernel fails to properly validate the return value from the alloc_workqueue function call. The flaw manifests during the initialization process of interrupt handling mechanisms for AMD GPU devices, where the system attempts to allocate a workqueue for asynchronous processing but does not verify whether this allocation succeeds before proceeding with subsequent operations.
From a technical perspective, the vulnerability stems from inadequate error handling within the kernel's GPU interrupt management subsystem. When alloc_workqueue fails to allocate the required workqueue structure, it returns a NULL pointer which is then subsequently dereferenced without proper validation. This null pointer dereference represents a fundamental violation of memory safety principles and can lead to immediate system instability or crash conditions. The issue falls under CWE-476 which specifically addresses NULL pointer dereference vulnerabilities, where a null pointer is used in a context that requires a valid object reference. The vulnerability is particularly concerning because it occurs within kernel space code that handles critical GPU interrupt processing, potentially affecting system stability during normal GPU operations.
The operational impact of this vulnerability extends beyond simple system crashes to potentially affect system availability and reliability in production environments. When the null pointer dereference occurs, it typically results in a kernel panic or system crash that requires manual intervention to recover. This can be particularly problematic in server environments or embedded systems where uninterrupted operation is critical. The vulnerability affects systems running Linux kernel versions up to and including 5.2.14, making it relevant to a significant portion of the Linux kernel ecosystem. Attackers who can trigger this condition may be able to cause denial of service scenarios by forcing system crashes, though the vulnerability does not appear to provide direct privilege escalation capabilities or data exposure.
Security researchers within the community have expressed significant skepticism regarding the severity classification of this vulnerability, with the security community disputing whether it merits a CVE identifier given its limited impact and the fact that it requires specific conditions to be triggered. The vulnerability is classified as a local denial of service issue that does not provide access to sensitive system resources or enable remote exploitation. However, from an operational standpoint, the vulnerability remains relevant due to its potential to cause system instability, particularly in environments where GPU functionality is heavily utilized. The issue demonstrates the importance of proper error handling in kernel space code, where even seemingly minor oversight in validation can lead to system-wide failures. Mitigation strategies include upgrading to kernel versions where this issue has been resolved, typically kernel versions 5.3 and later, where the return value validation has been properly implemented. Additionally, system administrators should monitor for any kernel panic events related to GPU interrupt handling and consider implementing robust system monitoring to detect potential trigger conditions. The vulnerability serves as a reminder of the critical importance of comprehensive error handling in kernel space components and aligns with ATT&CK technique T1499.004 which addresses network denial of service attacks through system resource exhaustion, though in this case the resource exhaustion manifests through kernel memory management failures rather than network resources.