CVE-2023-52474 is a vulnerability in the Linux kernel's hfi1 driver, specifically affecting the handling of user SDMA (Shared Direct Memory Access) requests with multiple payload iovecs (input/output vectors) that do not end at the PAGE_SIZE boundary. The vulnerability arises from two primary bugs in the user_sdma_txadd() and user_sdma_send_pkts() functions. First, user_sdma_txadd() incorrectly copies up to PAGE_SIZE bytes from an iovec without respecting the actual length specified by iov.iov_len, potentially including unintended data in the packet. Second, these functions fail to properly advance to the next iovec when the current iovec is shorter than PAGE_SIZE and insufficient to complete the packet, causing data corruption by transmitting incorrect data from the iovec pages. These bugs were not previously an issue with hfi1 Verbs or PSM2 SDMA packets because they only produce iovecs that end short of PAGE_SIZE as the tail iovec. Fixing these bugs revealed additional issues in the SDMA pin cache management, specifically in the mmu_rb_handler component responsible for managing pinned memory ranges. The identified mmu_rb_handler bugs include duplicate pinnings due to overlapping memory ranges, race conditions during extension of mmu_rb_node entries leading to insertion failures and improper unpinning of pages, unsafe reference count incrementing outside of locks causing potential eviction of nodes in use, and failure to check reference counts before freeing mmu_rb_node objects. These issues can result in use-after-free conditions where SDMA requests dereference freed memory, potentially leading to memory corruption or kernel crashes. Overall, this vulnerability involves complex memory management and data handling bugs in the Linux kernel's hfi1 driver that can cause data corruption, memory safety violations, and instability when processing user SDMA requests with multi-iovec payloads that do not align with page boundaries. Although no known exploits are reported in the wild, the nature of the bugs suggests potential for denial of service or data integrity attacks in affected environments.

For European organizations, the impact of CVE-2023-52474 depends largely on the deployment of Linux systems utilizing the hfi1 driver, which is typically associated with high-performance computing (HPC) environments and InfiniBand hardware. Organizations in sectors such as research institutions, universities, scientific computing centers, and industries relying on HPC clusters (e.g., automotive, aerospace, pharmaceuticals) may be affected if their infrastructure uses affected Linux kernel versions with hfi1 support. The vulnerability can lead to data corruption during SDMA operations, undermining the integrity of data transfers critical in HPC workloads. Additionally, the memory management bugs can cause kernel instability or crashes, resulting in denial of service conditions that disrupt computational tasks and services. Such disruptions could delay research, production processes, or critical simulations. While exploitation requires crafted multi-iovec SDMA requests and likely local access or privileged user capabilities, the risk remains significant in multi-tenant HPC clusters or environments where untrusted users have some level of access. The absence of known exploits reduces immediate threat but does not eliminate the risk, especially as patches are not yet widely deployed. European organizations should prioritize patching to maintain HPC system reliability and data integrity.

1. Apply official Linux kernel patches that address CVE-2023-52474 as soon as they become available from trusted sources or Linux distribution vendors. Monitor vendor advisories for updated kernel packages. 2. For HPC environments using InfiniBand hardware with hfi1 drivers, validate that kernel versions are updated and that SDMA request handling is secure. 3. Restrict user access to systems running affected kernels, especially limiting unprivileged users from submitting crafted multi-iovec SDMA requests. 4. Implement strict access controls and monitoring on HPC clusters to detect anomalous SDMA usage patterns that could indicate exploitation attempts. 5. Conduct thorough testing of HPC workloads after patching to ensure stability and data integrity. 6. Consider disabling or restricting hfi1 driver usage if not required, as a temporary mitigation until patches are applied. 7. Maintain up-to-date backups and system snapshots to recover from potential kernel crashes or data corruption incidents. 8. Engage with hardware and software vendors to confirm compatibility and support for patched kernel versions in HPC environments.