CVE-2024-47719 is a vulnerability identified in the Linux kernel's IOMMU (Input-Output Memory Management Unit) subsystem, specifically within the iommufd driver responsible for managing IOVA (Input-Output Virtual Address) allocations. The flaw arises due to an integer overflow in the ALIGN() macro during IOVA allocation when userspace supplies specially crafted iova and uptr values. This overflow causes the alignment calculation to wrap around, resulting in corruption of the allocated memory range. The vulnerability is triggered in the function iopt_alloc_area_pages within the io_pagetable.c source file. The root cause is that the automatic alignment can become excessively large, leading to fragmentation and improper handling of the IOVA space. The patch approach involves capping the automatic alignment to the huge page size, which prevents the overflow and reduces unnecessary fragmentation. Exploitation requires interaction with the iommufd interface, which is typically accessed via ioctl system calls. The vulnerability does not appear to require elevated privileges initially but does require userspace interaction with the vulnerable driver. There are no known exploits in the wild as of the publication date. The vulnerability affects Linux kernel versions around the 6.10.0-rc5 release candidate and likely other versions containing the iommufd driver with the flawed allocation logic. This vulnerability could be leveraged to cause memory corruption within the kernel's IOMMU subsystem, potentially leading to denial of service (kernel panic) or escalation of privileges if combined with other bugs. However, exploitation complexity is moderate due to the need to interact with specific kernel interfaces and supply carefully crafted parameters.

For European organizations, the impact of CVE-2024-47719 depends largely on their deployment of Linux systems utilizing the iommufd driver, which is commonly found in environments leveraging advanced IOMMU features for device virtualization, such as cloud infrastructure, data centers, and high-performance computing clusters. Successful exploitation could lead to kernel memory corruption, causing system instability or crashes, resulting in denial of service. In multi-tenant environments, this could disrupt critical services or virtual machines. Furthermore, if exploited in conjunction with other vulnerabilities, it could enable privilege escalation, threatening confidentiality and integrity of sensitive data. Given the widespread use of Linux in European public sector, financial institutions, and technology providers, any disruption or compromise could have significant operational and reputational consequences. The vulnerability's exploitation requires userspace access to the iommufd interface, which may be restricted in hardened environments, somewhat limiting the attack surface. However, organizations running containerized workloads or cloud platforms with less restrictive access controls may be more exposed. The lack of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits post-disclosure.

European organizations should implement the following specific mitigations: 1) Apply the official Linux kernel patches that cap the automatic alignment to the huge page size, as soon as they become available for their kernel versions. 2) Restrict access to the iommufd interface by enforcing strict permissions and limiting ioctl calls to trusted users and processes only. 3) Employ kernel lockdown features and mandatory access controls (e.g., SELinux, AppArmor) to reduce the ability of unprivileged users to interact with kernel drivers. 4) Monitor kernel logs for warnings related to iommufd allocations, as CONFIG_IOMMUFD_TEST can detect anomalous alignment conditions indicative of exploitation attempts. 5) In virtualized environments, isolate workloads and minimize exposure of IOMMU interfaces to untrusted tenants. 6) Maintain up-to-date inventories of Linux kernel versions in use and prioritize patching of systems running affected versions. 7) Conduct penetration testing focusing on IOMMU interfaces to identify potential exploitation paths. These steps go beyond generic advice by focusing on access control to the vulnerable interface, proactive detection, and environment-specific hardening.