CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's RDMA subsystem, specifically in the handling of completion queues (CQs) during their destruction process. It allows for a potential use-after-free condition, where resources associated with a CQ may be accessed after they have been freed, potentially leading to system instability or exploitation. Organizations utilizing Linux systems with RDMA capabilities should prioritize this fix to ensure the integrity and security of their network operations.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Fix potential use after free in ib_destroy_cq_user() When accessing a CQ via the netlink path the only synchronization mechanism for the said CQ is rdma_restrack_get(). Currently, rdma_restrack_del() is invoked at the end of ib_destroy_cq_user(), which is too late, since by that point vendor-specific resources associated with the CQ might already be freed. This can leave a short window where the CQ remains accessible through restrack, leading to a potential use-after-free. Fix this by moving the rdma_restrack_begin_del() call to the start of ib_destroy_cq_user(), ensuring that the CQ is removed from restrack before its internal resources are released. This guarantees that no new users hold references to a CQ that is in the process of destruction. In addition, this change preserves the intended inverted order between create and destroy routines: resources are added to restrack at the end of successful creation, and hence shall be removed from the restrack first thing during the destruction flow, which keeps the lifecycle management consistent and predictable.