CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's handling of zerocopy operations in the vsock/virtio subsystem, specifically when large messages are fragmented into multiple skbs. This flaw can lead to the leakage of pinned user pages without proper completion tracking, potentially allowing for resource exhaustion or denial of service. Organizations using Linux in environments that utilize vsock/virtio should prioritize applying the patch to mitigate this risk.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: fix zerocopy completion for multi-skb sends When a large message is fragmented into multiple skbs, the zerocopy uarg is only allocated and attached to the last skb in the loop. Non-final skbs carry pinned user pages with no completion tracking, so the kernel has no way to notify userspace when those pages are safe to reuse. If the loop breaks early the uarg is never allocated at all, leaking pinned pages with no completion notification. Fix this by following the approach used by TCP: allocate the zerocopy uarg (if not provided by the caller) before the send loop and attach it to every skb via skb_zcopy_set(), which takes a reference per skb. Each skb's completion properly decrements the refcount, and the notification only fires after the last skb is freed. On failure, if no data was sent, the uarg is cleanly aborted via net_zcopy_put_abort(). This issue was initially discovered by sashiko while reviewing commit 1cb36e252211 ("vsock/virtio: fix MSG_ZEROCOPY pinned-pages accounting") but was pre-existing.
Related CVEs
Other vulnerabilities affecting the same vendor(s)