Linux Kernel NFSv4 Delegation StateID Handling Vulnerability

A vulnerability in the Linux kernel's NFS server implementation has been addressed. The issue arose because the NFS server did not properly handle revoked delegation state IDs, leading to incorrect error responses. When a delegation is revoked, it is initially marked as revoked and later as freeable, indicating it is ready to be returned. However, the NFS server's state ID lookup function did not include the freeable status, causing revoked delegations to be nearly impossible to retrieve. This vulnerability affected the NFS server's ability to correctly manage delegation states, particularly in scenarios where a delegation was acquired, allowed to expire, and then revoked.

Impact

The vulnerability could lead to improper handling of NFS delegation state IDs, causing the NFS server to return incorrect error responses when delegated states are revoked.