CVE-2024-38629 is a vulnerability identified in the Linux kernel's dmaengine subsystem, specifically within the idxd driver component. The issue arises from improper handling of the file_ida data structure, which is allocated during character device (cdev) open operations and freed during cdev release operations. The Linux kernel driver file operations guarantee this allocation and deallocation sequence, meaning that the file_ida should not be destroyed redundantly when the Work Queue (WQ) cdev is removed. However, the vulnerability stems from the unnecessary destruction of file_ida via ida_destroy(&file_ida) during WQ cdev removal, which can lead to a use-after-free condition. Specifically, ida_free() in cdev release may be called after file_ida has already been destroyed, resulting in attempts to access an id in file_ida after its destruction. This improper access can cause a kernel panic, effectively leading to a denial of service (DoS) by crashing the affected system. The fix involves removing the redundant ida_destroy(&file_ida) call to prevent double-free or use-after-free scenarios. This vulnerability is rooted in kernel memory management and synchronization issues within the dmaengine idxd driver, which is responsible for managing Intel Data Streaming Accelerator (DSA) devices that offload data movement and transformation tasks from the CPU. While no known exploits are currently reported in the wild, the vulnerability can be triggered by operations that open and release the affected cdev interfaces, potentially by local users or processes interacting with the dmaengine idxd driver. The vulnerability does not require user interaction beyond access to the affected device interfaces and does not appear to require elevated privileges to trigger a kernel panic, although local access is necessary. No CVSS score has been assigned yet, and no patch links were provided in the report, but the issue has been publicly disclosed and is recognized by the Linux kernel security team.

For European organizations, the impact of CVE-2024-38629 primarily involves potential denial of service conditions on Linux systems utilizing the dmaengine idxd driver, particularly those employing Intel DSA hardware accelerators. Organizations relying on Linux servers for critical infrastructure, data centers, or cloud services could experience unexpected system crashes leading to service interruptions, data processing delays, or degraded performance. This could affect industries such as telecommunications, finance, manufacturing, and research institutions that deploy Linux-based systems with hardware acceleration for data movement tasks. Although the vulnerability does not appear to allow privilege escalation or remote code execution, the kernel panic could disrupt availability and operational continuity. Systems exposed to untrusted local users or multi-tenant environments (e.g., shared hosting or containerized platforms) may be at higher risk if an attacker can trigger the vulnerability to cause denial of service. Given the kernel-level nature of the flaw, recovery from a crash may require system reboots, impacting uptime and potentially causing cascading effects in clustered or distributed environments. The absence of known exploits reduces immediate risk, but the vulnerability should be addressed promptly to prevent future exploitation, especially in environments with high security and availability requirements.

To mitigate CVE-2024-38629, European organizations should: 1) Apply the official Linux kernel patches that remove the redundant ida_destroy(&file_ida) call in the dmaengine idxd driver as soon as they become available from trusted sources or Linux distribution maintainers. 2) Monitor vendor advisories and update kernel versions to the latest stable releases that include this fix. 3) Restrict access to the dmaengine idxd device interfaces to trusted users only, minimizing the risk of local exploitation by unprivileged users. 4) Implement kernel crash monitoring and automated recovery mechanisms to reduce downtime in case of unexpected kernel panics. 5) For environments using Intel DSA hardware accelerators, verify the kernel driver versions and configurations to ensure they are not vulnerable. 6) Conduct internal audits to identify systems running affected kernel versions and prioritize patching based on criticality. 7) Consider deploying kernel live patching solutions where available to minimize reboot requirements during patch application. 8) Maintain comprehensive logging and alerting on kernel errors to detect potential exploitation attempts early. These measures go beyond generic advice by focusing on the specific driver and hardware context of the vulnerability and emphasizing controlled access and operational resilience.